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Synthesizing ring structure aviation fuels from biomass-derived platform molecules is challenging, especially for bridged ring structure aviation fuels which are typically achieved from fossil-derived chemicals. Herein, we report the synthesis of a series of ring structure biofuels in two steps by a combination of a solvent-free Michael-cyclization reaction and a hydrodeoxygenation (HDO) reaction from lignocellulose-derived 5,5-dimethyl-1,3-cyclohexanedione. These biofuels are obtained with high overall yields up to 90%, which exhibit high densities of 0.81 g cm−3-0.88 g cm−3 and high volumetric neat heat of combustion (VNHOC) values of 36.0 MJ L−1-38.6 MJ L−1. More importantly, bridged-ring structure hydrocarbons can also be achieved in two steps by a combination of a Robinson annulation reaction and an HDO reaction to afford the final products at high overall yields up to 90%. The bridged-ring structure products have comparable high densities and high VNHOC values to the best artificial fuel JP-10 (0.94 g cm−3 and 39.6 MJ L−1). The results demonstrate a promising way for the synthesis of high-density aviation fuels with different fuel properties at high yields.

Torrefaction is a pretreatment method that converts biomass to a fuel-like substance that can replace coal for sustainable power generation. In this work, a thermodynamic-based process simulation model was developed to simulate the gasification of empty fruit bunch (EFB), with torrefaction as pretreatment, to determine the optimum conditions; equivalence ratio, reactor temperature, torrefaction medium concentration, steam-to-biomass (S/B) ratio and system configuration were studied to determine their influence on hydrogen concentration, higher heating value (HHV), syngas ratio and cold gas efficiency (CGE). The highest hydrogen yield was obtained at an S/B ratio of 1.3 at 800 °C, with a syngas ratio of 2.5 and a CGE of 84%. Concentration of torrefaction medium showed no effect on hydrogen concentration due to the simplicity of the model used, but work is in progress in this direction. Therefore, steam gasification is more suitable than air gasification in hydrogen production.

Boron is a very promising and highly attractive fuel because of high calorific value. However, the practical applications in explosives and propellants of boron have been limited by long ignition delay time and low combustion efficiency. Herein, nano-Al and graphene fluoride (GF) as surface activated materials are employed to coat boron (B) particles to improve ignition and combustion performance. The reaction heat of nano-Al coated B/KNO3 and GF coated B/KNO3 are 1116.83 J/g and 862.69 J/g, respectively, which are higher than that of pure B/KNO3 (823.39 J/g). The ignition delay time of B/KNO3 could be reduced through nano-Al coating. The shortest ignition delay time is only 75 ms for B coated with nano-Al of 8 wt%, which is much shorter than that of pure B/KNO3 (109 ms). However, the ignition delay time of B/KNO3 coated with GF has been increased from 109 to 187 ms. B coated with GF and nano-Al shown significantly influence on the pressure output and flame structure of B/KNO3. Furthermore, the effects of B/O ratios on the pressure output and ignition delay time have been further fully studied. For B/KNO3 coated with nano-Al and GF, the highest pressures are 88 KPa and 59 KPa for B/O ratio of 4:6, and the minimum ignition delay time are 94 ms and 148 ms for B/O ratio of 7:3. Based on the above results, the reaction process of boron coated with GF and nano-Al has been proposed to understand combustion mechanism.

A facile and economical approach was developed for the large-scale production of powdered core-shell structured PTFE/Al (CS-PA) energetic materials through ultrasonic-assisted mixing. The low-cost micrometer-sized PTFE and Al particles were used as starting materials. Under high-power ultrasonic waves, the PTFE powder was dispersed into nano-to sub-micrometer-sized particles and then encapsulated the Al microparticles to form the core-shell structure. The heat of combustion, burning rate, and pressurization rate of the powdered CS-PA were measured. The thermal-initiated reaction behavior was further evaluated using thermogravimetry-differential scanning calorimetry. Subsequently, the bulk CS-PA with a uniform microstructure was obtained via cold isostatic pressing of the powdered CS-PA followed by vacuum sintering. For the bulk CS-PA, the quasi-static compression behavior was characterized, and the impact-initiated reaction processes were conducted using the Split Hopkinson Pressure Bar (SHPB) and evaluated by a high-speed camera. Compared to physically mixed PTFE/Al materials, the powdered and bulk CS-PA demonstrated enhanced thermal- and impact-initiated reaction characteristics respectively, proving the effectiveness of our approach for constructing core-shell structures.

In order to reduce the emission of carbon dioxide, gas turbine power station will expect to use more clean fuels in the future, especially those like hydrogen. Hydrogen-rich fuel(syngas) combustion characteristics of the novel counter dual-swirl gas turbine combustor under fixed calorific value input were studied by experiment and numerical simulation. PIV and temperature rake were used respectively to obtain the velocity and temperature distribution in the combustion chamber. The turbulence model of Reynolds stress and the kinetic model of detailed chemical syngas combustion were used simultaneously in the computational simulations. Based on the obtained results, it was found that there is a reasonable agreement between the numerical results and the experimental data. The analysis shows that the flow field and temperature field of the combustor were almost unaffected by the change of hydrogen content and shows a nearly identical distribution structure under all conditions with hydrogen content below 90%; but when the H 2 content reaches 90%, the above characteristic plots were significantly changed. As the H 2 content in the fuel increases, on the center line of the combustor, the jet velocity of the fuel decreased, the temperature of the gas flow increased, the recovery coefficient of total pressure decreased, and the temperature distribution at the combustor outlet became more uniform. In addition, it is also found that the syngas turbine with the same output power consumed less fuel than the gas turbine with hydrocarbon fuel. This paper provides reference for the study of hydrogen-rich syngas turbine and the application of hydrogen-rich fuel in combustor of energy system.

The low density of mass and energy are the main reason for the underutilization of great potential of Empty Fruit Bunch (EFB) as a raw material of alternative and renewable fuels. The using of bintaro fruit as co-firing and treatment of torrefaction – densification processes were believed to increase the density of mass and energy of the EFB biopellet. This study aims to determine the effect of residence time, compaction pressure, and addition of bintaro fruit to the characteristics of EFB biopellet according to ISO 17225-6 standards. Biopellet manufacture was carried out two processes sequence, namely the torrefaction process and the densification process. The torrefaction process was carried out at 275oC with residence time variations 30, 45, and 60 minutes. The densification process was carried out without binder with compaction pressure variations 30, 40, and 50 bar. The addition of bintaro fruit was intended as co-firing of EFB at a ratio 70:30. The best characteristics of biopellet were obtained under conditions of 60 minutes residence time and 50 bar compaction pressures with 3.00% of moisture content, 7.90% of ash content, 8.70% of volatile content, 80.40% of fixed carbon content, 4719.59 cal/gr of heating value, and 1.28 gr/cm3 of density. Characteristics of moisture content and volatile content decreased while ash content, fixed carbon content, and heating value increased with increasing residence time. Characteristics of density increased with increasing compaction pressure. Characteristics of proximate and heating value increased while density properties of biopellet decreased with the addition of bintaro fruit as co-firing.

The heating furnace is a sizeable energy-consuming device in iron and steel industry. In compact strip production (CSP), the size of the heating furnace is large and the working conditions are complicated. Furthermore, the large fluctuation of furnace temperature leads to large loss of billet combustion and energy consumption. This paper deals with the design of hybrid intelligent control based on condition identification for the combustion process of the CSP heating furnace. By analyzing the process of the heating furnace and existing problems, the structure of a hybrid intelligent control system is proposed, and the working conditions are divided into two categories: stable and fluctuating. A fuzzy controller is designed to improve the control accuracy of furnace temperature under the stable working condition, and an expert controller is used to adjust the temperature rapidly under the fluctuating working condition. Besides, calorific value compensation is introduced to reduce the influence of calorific value of gas fluctuation on temperature. After verifying the effectiveness, the proposed method has been used in a steel plant and achieved a good control result. The intelligent control system improves the control precision of the furnace temperature and reduces energy consumption compared with the traditional control system.

The outstanding advantages of methanol such as low pollutant emissions of nitrogen oxides (NOx) and carbon monoxide (CO) make it a promising clean-burning fuel. Despite, the latent heat of vaporization of methanol is 3.70 times that of gasoline, the low heating value of methanol is one of the most critical barriers to its effective utilization in industrial applications. Thus, the methanol burner needs to be effectively designed to determine the desired combustion characteristics and the optimal design of this type of clean burner. Hence, this study presents a computational fluid dynamic analysis on the combustion characteristics of a methanol swirling burner with two layers of swirling blades. A particular focus of this study is emphasized on the effects of different swirling blade angles (45°+45°, 60°+60°, and 45°+60°) and various equivalence ratios (0.5, 0.75, 1.0, 1.25, and 1.75) on the combustion characteristics and pollutants formation of the swirl burner. The velocity and temperature profiles, combustion characteristics, and concentrations of major combustion species are analyzed in detail. The results show that the blade angle arrangement of 45°+60° exhibits the best combustion characteristics in comparison with the other blade angle arrangements. It is also found that the BA3 with an equivalent ratio in the range of 1.0~1.25 shows the best performance in the emissions of NOx and CO compared with other combinations of swirling blade arrangements and equivalence ratios. More specifically, the optimal equivalence ratio ranges from 1.0 to 1.25 at which the NOx and CO emissions are measured to be 27.0 and 11.0 mg/m3, respectively.

This study presents a sustainable method for the production of hydrogen gas without adding any catalyst from the hydrolysis of black Al dross. A pilot-scale experimental setup consisting of a reactor, a condenser, and control and measurement devices was constructed to perform chemical reactions and physical measurements. The dross used in experiments was not activated by any process and can be found in facilities (Al production plants or die casting factories) with a grain size lower than 400 μm. The chemical composition revealed by XRF showed that the black dross contained 41.96% Al. Major and minor crystalline phases present in the sample were detected by XRD. A set of experiments was performed to investigate the effects of gravimetric dross to water ratio, pH value, initial water temperature, the pressure of the reaction mixture in time for H2 synthesis. 120 L of gas were maximally produced after reacting 1 kg of Al dross with 2 kg of hot tap water at 100 °C. The H2 purity of the gas mixture and the calorific value of the mixture were respectively measured by gas chromatography and gas calorimeter as 93.24% and 2375 kcal/m3. After hydrolysis of the Al dross, XRD, SEM, and EDX analyses revealed the formation of hydrolysis products and their morphology. This showed that the resultant mixture tends to become harmless and can be used for various fields of the industry as a by-product.

Plasma gasification is a novel gasification technology that offers a promising treatment of kitchen waste (KW) and other types of waste (e.g., medical waste). By considering the dried flour and dried rice, a high power (∼35 kW) plasma gasification system for these two raw materials was achieved in this work. Then, the effects of particle sizes and plasma energy ratio (PER, the ratio of plasma energy and the low heat value of the feedstocks) for the dried rice are investigated and discussed. The particles size (

Efficient production of high purity hydrogen from reforming of natural or synthetic hydrocarbons is an enabling technology for the competitiveness of hydrogen-based systems. Specifically, fuel processors based on membrane-integrated reformers are one of the most promising technologies being potentially more efficient than state-of-the-art fuel processors. The effects of the operating parameters on the performance of the complete membrane-integrated fuel processor are relevant and have not been properly investigated, especially in terms of mutual interactions. Therefore, we analyze the effects of the pressure and temperature of the steam reforming reactor as well as of the steam to fuel and air to fuel ratios, on the system efficiency. To this aim, we use a steady state model developed in Aspen Plus® that implements a hybrid lumped-distributed parameter approach. To generalize our results to diverse system sizes and fuel compositions we conduct a dimensional analysis to express all the parameters in non-dimensional form. The results show that the fuel processor efficiency based on lower heating value varies between 75% and 84% as a function of the operating parameters. Notably, it always exceeds 75% that is the reference value for a state-of-the-art fuel processor based on pressure swing adsorption purification. We also note that the retentate composition has a relevant impact on the fuel processor operation. Specifically, when the retentate is rich in fuel content the fuel processor can turn in exothermic regime or can suffer oxygen starvation in the catalytic oxidation reaction. However, when the fuel processor operates in regular conditions the only relevant mutual interaction is between the steam to fuel and air to fuel ratios. Also, the fuel processor efficiency is mostly sensitive to the operating temperature and to the steam to fuel ratio. The 770 °C optimal temperature implies that only dense ceramic membranes can be used to build a fuel processor that operates at the maximum possible efficiency. Finally, leveraging on such results we evaluate the preliminary design of an innovative tubular plug flow reactor with layer catalysts.

T he co -co mbustion characteristics and kinetics of torrefied sugarcane bagasse (TB) , lignite (L) , and their blended samples were experimentally investigated using thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG) based on the Coat s- Redfern method for kinetic estimatio n. Their physicochemical properties were also investigate d. Raw bagasse was thermally treated in a laboratory - scale torrefactor at 275 °C with a torrefaction time of 60 min under an inert nitrogen environmen t. Then, the torrefied bagasse was blended with Thai lignite as a co-f uel at ratios of 5 0: 50 (TB50L50) , 7 0;30 (T B70L3 0) , and 9 0:10 (T B90L1 0) , respectivel y. Torrefaction improved the fuel properties and heating value of the raw bagasse as well as reducing the O / C and H/C ratio s. In addition, the blending of torrefied bagasse with lignite improved the combustion behavio r. The TGA and DTG results indicated that the ignition and burnout temperatures stepped downwards with different increasing ratios of torrefied bagass e. The co - combustion behavior at the maximum burning rate showed that the burnout temperatures of TB50L50, TB70L30, and TB90L10 were 532, 529, and 528 °C, respectively, indicating a slight decrease with an increasing torrefied bagasse blending rati o. These results were sufficient to provide comprehensive guidelines in terms of the design and operation of the combustion system for adding torrefied bagasse into the co-f iring proces s.

Beet pulp is an extremely very wet organic waste derived from sugar production. It can be utilized for energy purposes, e.g. biogas production or as very valuable fodder for animals, mainly horses. The high moisture content (80%) in beet pulp makes it an adequate feedstock for the hydrothermal carbonization process. Therefore, this study is focussed on the hydrothermal carbonization of beet pulp. The following parameters were studied: temperatures of 180, 200, and 220 °C through 1, 2, 3, and 4 h of residence time. The optimal conditions of the process were determined (220 °C and 1 h), based on the physical and chemical properties of solid product hydrochar. The ultimate and proximate analyses, high heating value, energy and mass yields, and energy densification ratio were investigated. The obtained hydrochars were of a coal-like solid biofuel, with high heating values much higher than raw feedstock (c.a. 150% higher). The combustion performance and kinetics of hydrochar based on TGA were determined, indicating better combustion. Moreover, the fibre analysis of hydrochar, supported by infrared spectra and scanning microscope analysis confirmed the changes in its structure. Concluding, organic waste, beet pulp, is of great potential as an energy source using the hydrothermal pretreatment process.

Recycling is the need of time and tyre pyrolysis is a process of recycling waste tyre to yield oil. A lot of research has been conducted on blending of diesel to produce oil but due to higher sulphur content and higher exhaust emission limits, use of tyre pyrolysis oil can be very beneficial. In the present study, our focus is on hybrid blends of oil generated, karanja biodiesel and diesel. One of the major problems with biofuel is the lower calorific value, but pyrolysis oil has higher calorific value. Hence the decision was made to blend karanja biodiesel and pyrolysis oil. The blends prepared are tyre pyrolysis (TP) 10%, karanja biodiesel (KB) 20% and diesel 70% called as TP10KB20. Similarly, TP20KB10 was also done. Further, equivalent blends of individual fuel source (TPO30 and KB30) are done and compared. Experimental investigation of hybrid blends (TP10KB20, TP20KB10) and equivalent source blend (TPO30, KBD30 and diesel) fuel are done on single cylinder CI engine. It was observed that performance and combustion of TP10KB20 and TP20KB10 were superior than any other individual blend and diesel. However, emission of TP20KB10 limits it use. Further, TP10KB20 has given superior performance, combustion and emissions characteristics compared to diesel and other blends.

In this work, it was shown that low-temperature plasma initiated in liquid-phase media in the discharge gap between the electrodes is capable of efficiently decomposing hydrogen-containing molecules of various organic compounds and their mixtures with the formation of gaseous products in which the proportion of hydrogen is more than 90% according to gas chromatography data. In the course of work, an experimental setup for hydrogen production was designed and manufactured, which includes a steel reaction chamber with a cooling jacket, a power supply with adjustable parameters, an ultrasonic generator and transducer, and a gas extraction system. Optimal conditions for the production of hydrogen (yield and selectivity) have been found, and principles have been developed for the automation of the process and the design of a semi-continuous pilot plant in order to increase productivity. The reaction products and the purity of the obtained hydrogen are characterized by a set of instrumental methods of physicochemical analysis, including gas and liquid chromatography, microscopy, calorimetry, and other methods. Preliminary estimates of the energy efficiency, calculated taking into account the heat of combustion of hydrogen and the initial substances, as well as the consumption of electricity, showed an efficiency level of about 60–70%, depending on the composition of the initial mixture. Theoretical calculations of the voltage and current of the discharge were also carried out during the simulation of the process, which are consistent with the experimental data. A by-product of hydrogen production by the acoustoplasma discharge method during the decomposition of organic liquids is carbon, which is formed in the form of agglomerates of nanoparticles of various structures and is deposited during the reaction at the bottom of the reaction chamber. As shown by the results of analyzes and stoichiometric calculations, the formation of these by-products consumes most of the carbon and oxygen contained in the molecules of the initial liquid, thereby the resulting gaseous mixture is significantly enriched in hydrogen. The resulting nanoparticles and their agglomerates can also be used as fillers, dyes, components of composite materials.

Due to strengthened emission regulations, it is difficult to continuously use fuels for internal combustion engines such as gasoline and diesel. Emulsion fuel is a technology that can simultaneously reduce NOx and PM, the biggest problems of existing compression ignition engines. Since conventional emulsification technology involve various limitations. An emulsion fuel was prepared using a porous membrane emulsification method that maximizes stability and production efficiency. The kinematic viscosity of the emulsion fuel according to the water content and temperature was evaluated. And various basic properties (sulfur content, flash point, kinematic viscosity, density, ultimate analysis, net calorific value, and gross calorific value) of the prepared fuel was requested from an external institute for validation. The density and kinematic viscosity increased as the water content used in the manufacture of emulsion fuel increased, and the density and kinematic viscosity decreased as the temperature of the fuel increased. Based on the measurement results, an empirical equation according to temperature and water content was proposed. The error rate of the derived empirical equation is mostly less than 5%. And in most cases, the adjusted R-square value exceeded 0.95, so the proposed empirical equation was considered reliable. The proposed empirical equation can be utilized for obtaining the basic data for the emulsion fuel or water blended fuel.

A novel comb-shaped polydimethylsiloxane derivative (DSCFT) was synthesized to endow the flame retardancy and antibacterial properties of cotton fabrics. The main functional group of DSCFT were tested by Fourier-transform infrared spectroscopy. The vertical combustion test and limiting oxygen index (LOI) were used to measure the flame retardancy of the samples. The cotton samples treated with 300 g/L DSCFT acquired LOI value of 28.2% without the after-flame and after-glow. The DSCFT successfully reacted with the cotton fabrics via the process of treatment were shown by scanning electron microscopy and energy dispersive spectrometer observation. Cone calorimetry and thermogravimetric test were used to evaluate the combustion behavior and thermal stability of treated cotton fabrics. The effective heat combustion and total heat release of treated sample were significantly reduced in comparison with blank fabrics, and 42.74% of the char residue was retained at 800 °C. In addition, the antibacterial radios of treated cotton specimens against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were 96.8%, and 97.1% in contrast to untreated samples. The tensile strength of cotton fabrics reduced within acceptable range. Thus DSCFT-treated cotton fabrics had the multiple functions of flame retardancy and antibacterial.

The widely used alkyd resin suffers not only the flammability but also the autoignition of resin waste. Its autoignition should result from the air-drying exothermic effect due to autoxidation and conversion of double bond. However, the air-drying exothermic effect is seldom studied. In this study, five soybean oil-based alkyd resins were synthesized. The content of double bond measured by the titration method increased linearly with increasing the molar fraction of maleic anhydride. After air-drying, the infrared spectroscopy absorption peak for the double bond disappeared. Considering that the curing originated from the conversion of chemical bonds, the exothermic effect was theoretically analyzed to be 1163–1455 kJ mol−1 double bond based on the air-drying mechanisms and the differences among chemical bond energies. According to thermodynamics principles, the air-drying exothermic effect was also derived from the measured heat of combustion. When the content of double bond increased from 2.19 mol kg−1 resin to 2.56 mol kg−1 resin, the exothermic effect linearly increased from 1352 kJ mol−1 double bond or 2.96 kJ g−1 resin to 2508 kJ mol−1 double bond or 6.42 kJ g−1 resin. The steady and unsteady autoignition theoretical analyses implied that due to the air-drying exothermic effect the alkyd resin waste with a certain thickness would catch fire within one working day.

The purpose of this work was to obtain single-sided tapes with different concentrations of kaolin and to check its impact on the self-adhesive properties of commercial adhesives. The most important self-adhesive properties were examined, such as tack, peel adhesion, shear strength, shrinkage, and thermal resistance. Tapes based on silicone PSAs with kaolin can be used in many branches of industry to bond elements operating at elevated temperatures, i.e., in aeronautics, aerospace including solar cells for satellites and space stations. There are few reports on one-sided adhesive tapes based on silicones with the addition of kaolin. However, taking into account the number of their potential applications, we did self-adhesive tests and explained how kaolin affects them. In addition, the reactivity of the crosslinking compound and silicone adhesive during the crosslinking process and the thermal effects of this process were also examined. In connection with the various applications of the obtained tapes, also the flammability and heat of combustion were tested, in accordance with applicable standards. As a result of the tests, one-sided self-adhesive tapes with new properties (increased temperature resistance, less shrinkage, and increased resistance to flammability) were obtained.

The catalytic gasification of Yuyang coal for the production of hydrogen-rich syngas has been performed in a novel decoupled dual loop gasification system using alkali-feldspar as an in-situ catalytic bed material. This experimental setup is comprised of a fluidized bed gasifier (FBG), a moving bed reformer (MBR), a riser combustor (RC) and a particle grading cyclone (PGC). By the PGC, two loops, i.e. a gasification loop with quartz sand as circulating bed material between the FBG and the RC and a reforming loop with alkali-feldspar as circulating bed material between the MBR and the RC, are formed. The effects of process parameters such as reformer temperature (700–850 °C), steam/coal ratio (S/C) (0.6–1.5) and air equivalence ratio (ER) (0.15–0.30) on the composition of product gas, lower heating value (LHV), tar content, yield of product gas, the carbon and water conversions and the cold gas efficiency were investigated. At the reformer temperature of 850 °C, the lowest tar content 5.8 g/Nm3 and the maximum yield of product gas 1.0 Nm3/kg daf were obtained. The addition of steam increased the H2 yield. The maximum hydrogen concentration of 65.1 vol% in product gas was attained at the S/C ratio of 1.5. Oxygen as a part of gasification agent led to the rise of CO2 concentration from 24.3 to 46.3 vol% and the reduction of H2 concentration from 54.4 to 33.0 vol% with the increase of ER from 0.15 to 0.30.

Natural gas with H2 is widely used for lean-burn combustion, which leads to NOx emission as the main problem for it. For decreasing NOx emission and increasing thermal efficiency, the investigation on seeking the influence of H2 fractions on the mixture of CH4 and CO2 was conducted. Firstly, the ignition timing was decided through thermal efficiency and brake mean effective pressure (BMEP) for CH4 only. Then, combustion characteristics of CH4, CH4+CO2 and CH4+CO2+H2 were compared with volume percentage of H2 changing from 5% to 30%. Finally, the H2 injection strategy was checked between closed and open valve injections. Among these discussions, thermal efficiency, power output, BMEP and fuel consumption were evaluated. Results show that CO2 addition decreases power output and BMEP, leading to much more fuel consumption and lower thermal efficiency. When H2 is added, at the rich mixture conditions (λ＜1.0), power output and thermal efficiency decrease sharply as the mixture is enriched. However, at the lean-burn conditions (λ＞1.0), the decrease in flow rate of lower heating value (LHV) and increase in power output finally result in the higher efficiency with H2 addition. Moreover, when λ＞1.0, both low fuel consumption and high efficiency can be obtained with H2 addition to achieve the high BMEP. Furthermore, the open valve injection could obtain higher thermal efficiency, power output and BMEP with lower fuel consumption, suggesting that the H2 injection strategy should be well controlled with the ignition timing.

Biofuels in the form of bio-oil and biochar have been produced by microwave heating of corn stover. Different adsorbents such as silicon carbide (SiC) and activated carbon (AC) with different ratios (10%, 20%, and 30%) to corn stover are investigated with the aims of enhancing the absorption of the microwave, maximizing the yields of the desirable products i.e. bio-oil followed by biochar as well as improving their qualities. Use of both the adsorbents improved the heating performance through increase in the maximal temperature and heating rate by 170 °C and 36 °C/min respectively compared to without adsorbent. Use of AC increased the yield of bio-oil up to 45 wt% while SiC increased the gas yields up to a maximum value of 48 wt%. The better physical properties such as 37%, 5.3, 2.9 mPa s, and 1 g/mL for water content, pH, viscosity and density respectively of bio-oil were obtained when using AC as an adsorbent. Also, use of AC helped in producing bio-oils which contained higher carbon and hydrogen contents as well as high calorific value (17 MJ/kg). Similarly, use of AC increased the contents of hydrocarbons and phenols in the bio-oil up to 36% and 28% respectively with low oxygen-containing compounds (2%). Also, use of AC produced the biochar having cleanest pores that were almost free of carbon-like impurities with a higher surface area of the pore (105.2 m2/g). In addition, biochar having low ash content, high carbon content, and calorific value (28 MJ/kg) were achieved. The net energy recovery with respect to raw corn stover was calculated to be of maximum value i.e., 55% when using AC. The AC and SiC were reused for further runs of the experiments (5 times) with few changes in the heating behavior and the yields of the pyrolytic products.

The tar formed within the producer gas is a major problem in the biomass gasification process. The catalytic cracking of tar is the best method to avoid tar production. In this work, heterogeneous tar cracking of rice straw was performed in a two-stage downdraft gasifier for the enhancement of syngas production using a catalyst such as red brick granules, copper wire turning, aluminium wire turning, and mild steel (MS) turning. The influence of operating conditions such as gasification temperature and packed volume of catalyst was examined for the maximum tar removal and high-quality syngas generation. Among all the catalysts, MS turning was recorded as the superior catalyst giving 59.58 vol% hydrogen productions, 97.81% tar conversion efficiency, and 2.11 of H2/CO ratio. The highest higher heating value (HHV) of 13.76 MJ/m3 was obtained for the copper wire catalyst. The elemental composition of the catalyst was analyzed using XRF analysis. Reaction kinetics was calculated using the distributed activation energy model (DAEM) for each gasification product. DAEM model provides the best match between the simulated values and experimental values for tar and each syngas component obtained from both homogeneous and heterogeneous runs.

Agro-industries, leveraged by the high demand of acai products, promote environmental impact through the generation of wastes in several locals in Amazon. The use with bioenergetic purposes has capacity to mitigate these scenario. Thus, the aim of the study was to characterize the biomass of acai seeds and establish the technical parameters of temperature and pressure of work to the production of briquettes of physical, mechanical and thermal quality. Temperatures of 120, 140 and 160 °C; and pressures of 15, 20 and 25 MPa were studied. We analyzed the briquettes mechanical compressive strength, rate of water absorption, rate of volumetric expansion and energy and apparent density. To the characterization of in natura seeds, the proximate analysis, chemical composition (extractives, holocellulose and lignin contents), higher, lower and useful heating value were determined. The proximate analysis indicated biomass thermal resistance, potential to direct burning and conversion by thermochemical processes. The lignin content may increase briquettes compressive strength produced in high temperatures. It was observed that the temperature had more influence in the evaluated briquettes characteristics than the pressure. The compressive strength was greater in 160 °C and 15 MPa briquettes, indicating that the lignin works as binder in this temperature, however, with pressure improvement the resistance is not favored due to the limit of resistance to compaction. The rate of water absorption decreased with the pressure increase and the temperature statistically affected in 140 °C briquettes. We observed volumetric expansion values in consonance to other found in dense biofuels of the literature. Further, the apparent density and energy density were favored by pressure improvement and the temperature helped in the increase of the apparent density. Moreover, the produced briquettes presented gain in the apparent density regarding the in natura biomass and had energy density comparable to coal and adequate to co-firing in boilers.

Lignite is easily oxidized, and spontaneous combustion occurs during its storage, which greatly reduces its calorific value and affects its quality and economic benefits. The surface properties of ...

To solve the poor fireproof performance of plant fibers, one of the technical difficulties, and use more straw fibers as construction materials, wheat straw fibers (WSFs) have been subject to flame-retardant modification. Then, tests and analysis over the modified WSFs per the burning behavior and pyrolysis performance have been made. The physical and mechanical, and thermal insulation properties of wheat straw fiber cement-based composites (WSFCC) at high temperatures were characterized. The results are as follows: Ammonium polyphosphate (APP), magnesium hydroxide (MH), and aluminum hydroxide (ATH), three fire retardants, all affect the chemical structure of WSFs. P, Mg, and Al elements of the three retardants are successfully adsorbed onto the fibers' surface subject to modification. Flame-retardant WSFs significantly outperforms the non-flame-retardant ones per thermostability and flame retardancy. The heat release rate (HRR), total heat release (THR), effective heat of combustion (EHC), and mass loss rate (MLR) of most flame-retardant WSFs are obviously lower than those of non-flame-retardant ones. The APP-modified WSFs demonstrate higher total smoke production (TSP), while WSFs modified with composite flame retardants perform better in flame retardancy and smoke suppression. The MLR of WSFCC at high-temperature increases as the temperature goes higher. The compressive and flexural strengths of WSFCC decrease with the increase of temperature and the decrease mitigates after 350 °C. In terms of thermal conductivity, composite-flame-retardant fiber WSFCC are much higher than non-flame-retardant fiber and APP-modified fiber WSFCC. As the temperature rises, the thermal conductivity of composite-flame-retardant fiber WSFCC tends to decrease.

Fuel-film cooling is necessary to mitigate heat transfer in high-pressure oxygen-rich staged combustion engines. A 4.8 MPa (700 psia) axisymmetric kerosene–H2O2 combustor used fuel-film cooling to ...

With the rapid development of aerospace industry, it is significantly necessary to develop advanced rocket fuels with high density, high specific impulse and good combustion performance. In this work, we report the synthesis of cyclopropanated pinanes through cyclopropanation of pinene. The reaction conditions including reaction time, solvent type, halohydrocarbon and molar ratio of zinc carbenoid to pinene were optimized. The basic physical properties of fuel, including density, kinematic viscosity, freezing point, calorific value, and combustion performance were tested, and the specific impulses of cyclopropanated pinanes were also calculated. Importantly, the cyclopropanated α- and β-pinane possess high density of 0.90 and 0.91 g/mL, specific impulse of 330.58 and 330.39 s, which results in higher volumetric specific impulse than reported rocket fuels. They also show good low-temperature performance and better ignition and combustion performance than JP-10. These excellent performances indicate that the cyclopropanated α- and β-pinane have great application prospect as high-energy rocket fuel.

This work aims to present the thermal behaviour and pyrolytic kinetics of coconut shell (CS) at various heating rates of 10–50 °C/min to explore the potential of co-gasification with palm kernel shells (PKS) at varying proportions of 10–50%. The degradation profiles have been observed, and the activation energy (Ea) for CS (91.47–50.79 kJ/mol) was found to vary with the increase in heating rate. Ea for the blends of PKS-CS was ranged from 53.35 to 72.21 kJ/mol. The syngas produced through co-gasification had a calorific value of 2.6–3.2 MJ/Nm3 for various PKS-CS blending ratios. This study with predicted possible synergistic effect could propose the appropriate blending ratio of PKS with CS for co-gasification and promote the agro industry process waste PKS as a suitable single feed and multi-feed fuel source for gasification. Moreover, it also helps offset the concerns of fuel feedstock availability due to demand, seasonal variation and transportation cost for the continuous operation of biomass gasifier plants in remote areas.

At present, there is a shortage of experimental and simulation studies on fire spread in medium- and large-scale compartments while the existing models of the fire spread are limited for typical engineering applications. This paper proposes a new model for large-scale fire spread on medium density fibreboard (MDF) panels. Validating the model with single burning item (SBI) experiments, it is found that the numerical simulation closely predicts the experimental heat release rate (HRR) with some error near the peak. The predicted heat flux and distance of lateral flame spread are consistent with the experiments and an existing model. The effects of kinetic properties and heat of combustion are identified through a sensitivity analysis. The decrease of activation energy and increase of pre-exponential factor make the MDF easier to pyrolyze and the increase of heat of combustion enhances the flame temperature and thus provide more heat feedback to the sample surface. The low activation energy (71.9 kJ/mol) and high heat of combustion (46.5 MJ/kg) of the model ensure the occurrence of flame spread. Furthermore, the model was validated using medium-scale compartment fire experiments and the results showed that the model can accurately predict the HRR after flashover (the error is within 7%). While the burner is ignited, the predictions of in-compartment gas temperature and heat flux are more accurate. However, when the burner is extinguished, the modelled in-compartment gas temperature is lower than the experimental values, resulting in a lower heat flux prediction. The model leads to easier flame spread; therefore, the modelled flame spreads faster in the compartment compared to the experiment, and thus the HRR increases more rapidly.

Thermal pretreatment by torrefaction is known to produce improved properties in biomass fuels, but the role of pellet size on key properties in commercially available hardwood derived fuel has not been investigated to date. In this study, densified Australian woody biomass was torrefied over different temperatures (250–300 °C), time (30 and 60 min) and mean pellet size (7 ± 0.5 mm and 15 ± 0.5 mm). Benchmarking, relative to raw fuel properties, is reported in terms of proximate analysis, high heating value (HHV) and water immersion tests as well as FTIR and thermal stability (TGA). Significant differences of 23.55% in mass loss (ML) and 10% in hygroscopic behaviour were observed at varied pellet size. FTIR analysis of the samples identified reduction of polar species such as the hydroxyl (-OH) functional group during torrefaction. This increased the hydrophobicity of torrefied pellets. Torrefaction of larger sized pellets was also accompanied with lower hemicellulose and cellulose degradation. A correlation predicted the HHV of the torrefied pellets which fits well with the actual HHV’s of the wide body of literature with an average difference of less than 1 MJ/kg. Pellet sizing was found to impact the fuel properties only at milder torrefaction conditions. As such, with the increase in torrefaction severity, the effect of pellet size became insignificant. The outcomes emphasise the need to describe pellet size distributions when reporting torrefaction performance indicators, particularly if commercial scale torrefaction is used at higher temperatures and longer times.

MgH2, TiH2, and ZrH2 are three typical metal hydrides that have been gradually applied to composite explosives and propellants as additives in recent years. To evaluate ignition sensitivity and explosion severity, the Hartmann device and spherical pressure vessel were used to test ignition energy and explosion pressure, respectively. The results showed that the ignition sensitivity of ZrH2, TiH2 and MgH2 gradually increased. When the concentration of MgH2 is 83.0 g/m3 in Hartmann device, the ignition energy attained a minimum of 10.0 mJ. The explosion pressure of MgH2 were 1.44 times and 1.76 times that of TiH2 and ZrH2, respectively, and the explosion pressure rising rate were 3.97 times and 9.96 times that of TiH2 and ZrH2, respectively, through the spherical pressure vessel. It indicated that the reaction reactivity and reaction rate of MgH2 were higher than that of TiH2 and ZrH2. In addition, to conduct in–depth theoretical analysis of ignition sensitivity and explosion severity, gas production and combustion heat per unit mass of ZrH2, TiH2 and MgH2 were tested by mercury manometer and oxygen bomb calorimetry. The experimental results revealed that MgH2 had a relatively high gas production per unit mass (5.15 mL/g), while TiH2 and ZrH2 both had a gas production of less than 2.0 mL/g. Their thermal stability gradually increased, leading to a gradual increase in ignition energy. Furthermore, compared with theoretical combustion heat, the combustion ratio of MgH2, TiH2 and ZrH2 was more than 96.0 %, with combustion heat value of 29.96, 20.94 and 12.22 MJ/kg, respectively, which was consistent with the explosion pressure and explosion severity test results.

This experimental study has confirmed that during thermal decomposition of polymeric waste samples at a temperature of 850°C, without oxygen access, there is a 90% drop in the mass of this waste with the release of a large volume of gaseous products. This feature should be taken into consideration in the engineering calculations of reaction chambers, reactors, and connecting gas pipelines. The analytical study was carried out by a method of thermodynamic analysis using the universal estimation system Astra (TERRA). It has been shown that with an increase in reaction temperature there is a change in the composition of the products of thermal destruction of polymeric waste by reducing the mole fraction of СН4and increasing the proportion of Н2. The calorific value was calculated according to Mendeleev’s empirical formula. The experimental study (a pyrolysis-gas chromatography method) has confirmed the calculation results regarding an increase in the proportion of hydrogen in the gaseous products of destruction with an increase in process temperature. As a result, due to the lower volumetric heat of hydrogen combustion, the total caloric content of the synthesis gas obtained is significantly reduced. For the experiments, a laboratory installation of low-temperature pyrolysis of polymers with external supply of thermal energy was built, and synthesis gas was used as an energy carrier. At the experimental-industrial installation, by a low-temperature pyrolysis method, the synthesis gas of a stable composition with a lower heat of combustion of 24.8kJ/m3was obtained. The reliability of the results of the proposed estimation method to the results of instrumental measurements has been shown. Promising areas of further studies have been determined, including the optimization of processes of thermal destruction of chlorine-containing polymer waste; the effective use of hydrogen from the composition of the synthesis gas obtained.

Algae biomass has been recognized as one of the most suitable, efficient, and reliable feedstocks for bio-oil production. Among the different processes, hydrothermal liquefaction (HTL) is emerging as an effective technology for the valorization of various types of wet or dry biomass. Several factors, including temperature, retention time, and catalyst, significantly influence the overall efficiency of HTL products. The temperature ∼280 ± 40 °C is reported to be the most suitable range to achieve maximum bio-oil. Both homogeneous and heterogeneous catalysts have been used to improve bio-oil yield. For several advantages, heterogeneous catalysts are the preferred choice due to improved bio-oil generation, easy recovery, and uses. The eco-friendly approach and the reduction of heteroatoms in bio-oils make heterogeneous catalysts an ideal choice to be fortified. Alkaline catalysts have been considered most suitable to improve HTL yield. Variations in temperature and catalysts not only influence the yield of the bio-oil but also influence the characteristics of the bio-oil (e.g. high heating value, oxidative stability, gaseous emission, etc.) simultaneously. This review reveals interesting features including HTL temperature vs. yield, catalysts vs. yield, and the effect of wet and dry biomass on bio-oil properties, and finally, observations, remarks/limitations are presented for future studies.

The use of gasoline for primary energy consumption can reduce crude oil, contained in the earth. The development of alternative fuels such as biogas and biofuel is very critical to overcoming this problem. Biogas requires purification to remove some contaminant particles that interfere with the combustion process. The packed column is generally applied to absorb and separate gas and liquid mixture. It is more efficient due to the liquid flows down the column of steam naturally without the supply of energy from outside the system. This study focuses on determining the effect of the packed column biogas purification process. Biogas is applied as an alternative fuel in spark-ignition engines (SIE). The test is carried out using a chassis dynamometer to obtain power and torque data. The use of the packed column for biogas fuel purification can produce higher performance compared to unrefined biogas. The unrefined biogas still contains impurities that can interfere with the combustion process. This condition is proven by measuring the power and torque of the vehicle on the chassis dynamometer, where the filtered biogas produces higher power and torque. Tests were carried out both using the packed column and without the packed column. Variations from speed to torque, to power, to SFC and BMEP are considered. In this study, validation is in good agreement with previous studies. Overall, the results show that the average error between using the packed column and without the packed column for torque, power, SFC and BMEP is increased by approximately 7 %. Purification of biogas using the packed column using Ca(OH)2 can bind CO2 and obtain pure methane gas with a higher heating value. In conclusion, the packed column for biogas purification as fuel for motorcycle injection systems can be applied, Использование бензина для потребления первичной энергии может привести к уменьшению количества сырой нефти, содержащейся в земле. Для решения этой проблемы крайне важное значение имеет разработка альтернативных видов топлива, таких как биогаз и биотопливо. Биогаз требует очистки для удаления загрязняющих веществ, которые мешают процессу горения. Для поглощения и разделения газожидкостной смеси обычно применяется насадочная колонна. Это более эффективно, поскольку жидкость стекает по столбу пара естественным путем без подачи энергии извне. Данное исследование направлено на определение результатов очистки биогаза в насадочной колонне. Биогаз применяется в качестве альтернативного топлива в двигателях с искровым зажиганием. Проводится испытание с использованием динамометрического стенда для получения данных о мощности и крутящем моменте. Использование насадочной колонны для очистки биогазового топлива может обеспечить более высокую производительность по сравнению с неочищенным биогазом. Неочищенный биогаз содержит примеси, которые могут помешать процессу сгорания. Это условие подтверждается измерением мощности и крутящего момента транспортного средства на динамометрическом стенде, где отфильтрованный биогаз обеспечивает более высокую мощность и крутящий момент. Испытания проводились как с использованием насадочной колонны, так и без. Рассматриваются изменения скорости, крутящего момента, мощности, удельного расхода топлива и среднего эффективного тормозного давления. Данное исследование согласуется с предыдущими исследованиями. В целом, результаты показывают, что средняя погрешность при использовании насадочной колонны и без насадочной колонны для крутящего момента, мощности, удельного расхода топлива и среднего эффективного тормозного давления увеличивается примерно на 7 %. Очистка биогаза с помощью насадочной колонны с использованием Ca(OH)2 может связывать CO2 и позволяет получать чистый газ метан с более высокой теплотворной способностью. В заключение можно отметить возможность применения насадочной колонны для очистки биогаза в качестве топлива для систем впрыска мотоциклов, Використання бензину для споживання первинної енергії може призвести до зменшення кількості сирої нафти, що міститься в землі. Для вирішення цієї проблеми вкрай важливе значення має розробка альтернативних видів палива, таких як біогаз і біопаливо. Біогаз вимагає очищення для видалення забруднюючих речовин, які заважають процесу горіння. Для поглинання і розділення газорідинної суміші зазвичай застосовується насадкова колона. Це більш ефективно, оскільки рідина стікає по стовпу пари природним шляхом без подачі енергії ззовні. Дане дослідження спрямоване на визначення результатів очищення біогазу в насадковій колоні. Біогаз застосовується в якості альтернативного палива в двигунах з іскровим запалюванням. Проводиться випробування з використанням динамометричного стенду для отримання даних про потужність і крутний момент. Використання насадкової колони для очищення біогазового палива може забезпечити більш високу продуктивність в порівнянні з неочищеним біогазом. Неочищений біогаз містить домішки, які можуть перешкодити процесу згоряння. Ця умова підтверджується вимірюванням потужності і крутного моменту транспортного засобу на динамометричному стенді, де відфільтрований біогаз забезпечує більш високу потужність і крутний момент. Випробування проводилися як з використанням насадкової колони, так і без. Розглядаються зміни швидкості, крутного моменту, потужності, питомої витрати палива і середнього ефективного гальмівного тиску. Дане дослідження узгоджується з попередніми дослідженнями. В цілому, результати показують, що середня похибка при використанні насадкової колони і без насадкової колони для крутного моменту, потужності, питомої витрати палива і середнього ефективного гальмівного тиску збільшується приблизно на 7 %. Очищення біогазу за допомогою насадкової колони з використанням Ca(OH)2 може зв'язувати CO2 і дозволяє отримувати чистий газ метан з більш високою теплотворною здатністю. На закінчення можна відзначити можливість застосування насадкової колони для очищення біогазу в якості палива для систем упорскування мотоциклів

Understanding optimal process conditions is an essential step in providing high-quality fuel for energy production, efficient energy generation, and plant development. Thus, the effect of process conditions such as the temperature, time, nitrogen-to-solid ratio (NSR), and liquid-to-solid ratio (LSR) on pretreated waste pine sawdust (PSD) via torrefaction and solvolysis is presented. The desirability function approach and genetic algorithm (GA) were used to optimize the processes. The response surface methodology (RSM) based on Box–Behnken design (BBD) was used to determine the effect of the process conditions mentioned above on the higher heating value (HHV), mass yield (MY), and energy enhancement factor (EEF) of biochar/hydrochar obtained from waste PSD. Seventeen experiments were designed each for torrefaction and solvolysis processes. The benchmarked process conditions were as follows: temperature, 200–300 °C; time, 30–120 min; NSR/LSR, 4–5. In this study, the operating temperature was the most influential variable that affected the pretreated fuel’s properties, with the NSR and LSR having the least effect. The oxygen-to-carbon content ratio and the HHV of the pretreated fuel sample were compared between the two pretreatment methods investigated. Solvolysis pretreatment showed a higher reduction in the oxygen-to-carbon content ratio of 47%, while 44% reduction was accounted for the torrefaction process. A higher mass loss and energy content were also obtained from solvolysis than the torrefaction process. From the optimization process results, the accuracy of the optimal process conditions was higher for GA (299 °C, 30.07 min, and 4.12 NSR for torrefaction and 295.10 °C, 50.85 min, and 4.55 LSR for solvolysis) than that of the desirability function based on RSM. The models developed were reliable for evaluating the operating process conditions of the methods studied.

A number of significant parameters such as gasification temperature, dimensions of gasifier, nature of feedstock, position of the components, particle size of feedstock, inlet air temperature, equivalence ratio, and type of gasifier highly influence the yield and characteristics of producer gas (PG). However, structural design of the air nozzle and temperature of the inlet air have received significant attention in enhancing the composition of producer gas and its gasification efficiency. In this study, species transport model of the numerical simulation had been selected to analyze the performance parameters of a gasifier for the air nozzle’s angle and inlet air temperature from 0 to 60° and 27 to 627 °C, respectively. Rice husk was used as the feedstock. For the accuracy of simulation, the results were compared with an experimental study. The combustible gas composition, higher heating value of PG was analyzed in both numerical and experimental studies; furthermore, the prevailing temperature inside the gasifier was also keenly observed and recorded. Among the various nozzle positions, the composition of CO, H2, and CH4 in the producer gas was better at 45° nozzle inclination with 627 °C inlet air temperature; moreover, the composition of the gaseous compounds in the PG were found as 19 to 23%, 13 to 15%, and 2 to 3% respectively. For the above-mentioned conditions of nozzle inclination and inlet air temperature, the calorific value of producer gas was in the range of 4–6 MJ/Nm3. The temperature distribution in the combustion, reduction, pyrolysis, and drying zones was in the range of 1000–1200 °C, 600–700 °C, 300–420 °C, and 200–300 °C, respectively.

Emission amount of blast furnace gas (BFG) is huge per year and it cannot be directly combusted due to its low heat value. Separating and Enriching CO from blast furnace gas provides an effective w...

In recent years, with the rise of global environmental protection activities, it is becoming necessary to reduce CO2 emissions in social activities. In the field of power generation, it is very important to capture CO2 emissions and increase the conversion efficiency from chemical energy to electrical energy. Because the increased electrical efficiency can lead to the increased power, it is likely to reduce the consumption of fossil fuels for power generation, resulting in reduced CO2 emissions. In our previous report, the effect of a fuel regenerator in a two-stage solid oxide fuel cell (SOFC) module on the electrical efficiency was studied. The results showed that the electrical efficiency was considerably improved by removing H2O and CO2 from the anode off-gas by the fuel regenerator. The highest electrical efficiency was obtained when 100% of H2O and CO2 were removed from the anode off-gas, and it was estimated to be a net alternating current (AC) of 71.8% (lower heating value (LHV)). Although it is necessary to maintain the module at a high temperature in order to realize the system, a 4.8 kW two-stage SOFC module with a fuel regenerator was developed and confirmed to have the electrical efficiency equivalent to a net AC of 66.0% (LHV) with the thermal self-sustainability. In 2020, a demonstration test using a highly efficient two-stage SOFC system has started. In this study, we focused on an anode off-gas recycling SOFC module with a fuel regenerator. The reason why we studied the module is that it can generate highly efficient power and capture a large amount of CO2 at the fuel regenerator. Therefore, the effect of the fuel regeneration on both the electrical efficiency and capture of CO2 was examined. The authors are presently not aware of any reports of examining the effect of the fuel regenerator, which removes CO2 and/or H2O extensively from the anode off-gas, on the electrical efficiency and CO2 capture in an anode off-gas recycling SOFC module. The calculation was carried out under the following conditions. CH4 was used as a fuel, and the ratio of steam to carbon of the inlet fuel was 2.5 or more in order to avoid the carbon deposition. The temperature of both the reformer and SOFC stack was set at 700°C. The area specific resistance and current density of the SOFC stack were assumed to be 0.383 ohm cm2 and 0.25 A cm–2, respectively. The lowest available fuel concentration, which is assumed to be the ratio of the partial pressure of hydrogen to water vapor (= p(H2) / p(H2O)), was set by calculating the outlet fuel concentration when operating a single-pass SOFC stack with a maximum fuel utilization rate of 80%. For estimating the system performance, the inverter efficiency and auxiliary device loss rate were assumed to be 95% and 6%, respectively. The Nernst voltage was determined from the inlet and outlet gas composition of the stack which is calculated by a process simulation software. The electrical efficiency was estimated from the cell voltage and fuel utilization rate. The highest electrical efficiency was obtained when both the fuel utilization rate and recycle rate were 100%, and the removal rates of CO2 and H2O at the fuel regenerator were 100% and 44.4%, respectively. The reason to remove only 44.4% of H2O from the anode off-gas is to keep the ratio of steam to carbon of the inlet fuel at 2.5. The electrical efficiency was a net AC of approximately 75.5% (LHV) with 100% of CO2 capture at the fuel regenerator. In addition, the CO2 removal rate was studied to reduce to 63.9% because there is a margin in the fuel concentration of the SOFC stack. Even if the removal rates of CO2 and H2O at the fuel regenerator were 63.9% and 44.4%, respectively, the electrical efficiency was estimated to be a net AC of approximately 74.9% (LHV), and the CO2 capture at the fuel regenerator was 100%. These results show that the anode off-gas recycling SOFC module can generate highly efficient power as well as the two-stage SOFC module when using the fuel regenerator. Furthermore, the anode off-gas recycling SOFC module has advantage of capturing CO2 at the fuel regenerator. Although it is not easy to generate highly efficient power with the thermal self-sustainability, it is expected that the anode off-gas recycling SOFC module with the fuel regenerator is developed and put into practical use in the future.

The possibility of using a thermochemical detector to determine the heat of combustion of natural gas has been theoretically substantiated. It was found that the degree of combustion of combustible gases in thermochemical gas analyzers based on measuring the temperature of combustion products depends on the volume and type of catalyst, the flow rate of the analyzed gas and the concentration of combustible gases in it, as well as on the temperature, determines the need to ensure a greater degree of combustion of combustible substances. selection of the catalyst layer thickness, its activity, temperature and determination of the permissible concentrations of the components in the gas stream. The use of a pulse mode of operation in gas analyzers with thermocatalytic converters will ensure the constancy of the volumetric flow rate of the analyzed gas into the detector, is a decisive factor in ensuring the accuracy of measuring the thermal effect of catalytic combustion; carry out the process of catalytic combustion at low concentrations of combustible components in the flow of the carrier gas (air) by selecting the sample volume, is introduced into the analyzer, which can ensure the stability of the catalyst properties for a long time.

In this study, the simulation of a newly designed wind-sifter separator for dry beneficiation was deployed to upgrade -6.7 + 3.36, -3.36 + 1, and -1 mm coal. The wind-sifter principle is very effective for particle separation as it is based on the separation of lighter particles from heavier ones. First, the study entails computer simulations by utilizing the Lagrangian particle tracking method to observe the effectiveness of the wind sifting principle in separating particles based on their density in an air stream. From the three particle size fractions used, the simulation test results show that at a cut-point of 1.5 RD, yields of 29.1, 54.3, and 99.4% were attained at different optimum velocities for -6.7 + 3.36, -3.36 + 1, and -1 mm, respectively. The effect of operating parameters such as the mass flowrate and air velocity on yield, ash content, and calorific value were determined using the fabricated separator. A preliminary experimental study showed that the separator was effective in upgrading the feed coal with 30.28% ash content and 21 MJ/kg calorific value to clean coal with 18.94% ash content and 26.8 MJ/kg calorific value. A laboratory-scale wind-sifter separator was fabricated based on the results from the simulation test, which served as the first applied prototype in the field of dry coal beneficiation.

The main aim of this study is to investigate the thermal behaviour of the different parts of almond shells produced in an almond industry as a waste biomass. For this purpose, several experiments have been conducted under laboratory conditions. After removing the mature almonds, the waste raw materials subject of this study were treated with distilled water (10 min) and separated in several parts. Taking into account their physical characteristics, they were: (a) complete shells: exocarp, mesocarp and endocarp without grinding (Sample C); (b) ground samples of complete shells, sieved under 0.2 mm (Sample M); (c) hard layers of the endocarp (Sample E); (d) internal layers of the endocarp (Sample I); and (e) mature drupes (Sample P) or skin, being constituted by the flexible part of green colour (fresh form) or yellow (after drying). The thermal behaviour of all these sample materials has been investigated using a laboratory furnace, with determination of ash contents and mass loss by progressive heating (120 min of holding time). Elemental and DTA-TG/DTG analyses of selected sample materials have been carried out. Although a complete study can be very complex, a first approach has been performed in this investigation. Results on thermal decomposition of this biomass waste have been presented to emphasize the main differences between sample materials of almond shells. These results have demonstrated the influence of several parameters, such as the particle size, and previous treatments in the thermal behaviour of the different parts of the almond shells, as showed in this investigation. Structural analysis of almond shells allowed to determine lignin, cellulose and hemicellulose. From the lignin content, it has been predicted the higher heating value (18.24 MJkg−1) of this waste as by-product of industrial interest. Other linear correlations to calculate this parameter have been applied with similar results in all these samples.

Rotary engine is an ideal electric vehicle range extender. However, the combustion chamber of rotary engine is very narrow and long at the top dead center, which is detrimental to fuel combustion performance. In order to improve its economic and emission performance, this paper built an ethanol/gasoline dual-fuel rotary engine test bench, and the combustion and emission performance of gasoline rotary engine under five ethanol blending ratios were studied. The experimental results showed that, when the fuel pulse width is not adjusted, since the calorific value of ethanol is lower than that of gasoline and the latent heat of vaporization of ethanol is higher than that of gasoline, the addition of ethanol in gasoline lowers the peak pressure. When the ethanol blending ratio reaches 30 vol%, the pressure curve shows a distinct double peak. Under the theoretical air-fuel ratio condition, mixing ethanol in gasoline increases the heat release rate, shortens the combustion duration while prolonging delay period. After blending ethanol, HC, CO and NOx emissions have been reduced under various operating conditions. Excessive ethanol blending ratio increases NOx emissions and increases cycle variation coefficient. When the ethanol blending ratio is 15 vol%, it has better power ability while maintaining low cycle variation coefficient and emissions.

High-energy-density liquid hydrocarbon fuels are generally synthesized using various chemical reactions to improve the performance (e.g., range, load, speed) of aerospace vehicles. Compared with conventional fuels, such as aviation kerosene and rocket kerosene, these liquid hydrocarbon fuels possess the advantages of high-energy-density and high volumetric calorific value; therefore, the fuels have important application value. The photocatalytic process has shown great potential for the synthesis of a diverse range of fuels on account of its unique properties, which include good efficiency, clean atomic economy, and low energy consumption. These characteristics have led to the emergence of the photocatalytic process as a promising complement and alternative to traditional thermocatalytic reactions for fuel synthesis. Extensive effort has been made toward the construction of catalysts for the multiple photocatalytic syntheses of high-energy-density fuels. In this review, we aim to summarize the research progress on the photocatalytic synthesis of high-energy-density fuel by using homogeneous and heterogeneous catalytic reactions. Specifically, the synthesis routes, catalysts, mechanistic features, and future challenges for the photocatalytic synthesis of high-energy-density fuel are described in detail. The highlights of this review not only promote the development of the photocatalytic synthesis of high-energy-density fuel but also expand the applications of photocatalysis to other fields. Graphic abstract

Drop tube furnace is a high-efficiency pyrolysis reactor, which is helpful for fundamental research of coal base poly-generation technology. In this paper, the characteristics of coal pyrolysis product at various temperature using drop tube furnace were investigated. A typical Chinese lignite Pingzhuang coal was used in current research, pyrolysis temperature ranged from 600 to 1000 °C with a step of 100 °C. The compositions of pyrolysis gas, coal tar and char were characterized and discussed in detail. Results showed that volatiles and moisture content decreased after pyrolysis, hydrophilic functional groups like carboxyl and hydroxyl also decreased, pyrolysis was a dehydration upgrading process for lignite. Specific surface area and total pore volume increased from 1.65 m2/g and 11.57 mm3/g in raw coal to 199.10 m2/g and 191.95 mm3/g in 1000 °C char, respectively. As for pyrolysis gas, when temperature increased, H2 and CO increased obviously, other compositions like CO2, CH4 and C2~C3 hydrocarbons decreased, consequently, the gross heating value of pyrolysis gas decreased from 22.5 MJ/m3 at 600 °C to 13.1 MJ/m3 at 1000 °C. High temperature pyrolysis had a high content of syngas (H2+CO), which can be utilized as raw material in synthetic chemical industry. There were high content of toluene in low temperature coal tar. There were more polycyclic aromatic hydrocarbons and less aliphatic chain hydrocarbons in high temperature coal tar.

Melina wood torrefied at 260 °C for 60 min was agglomerated with lean grade coal fines into composite briquettes using pitch as binder. Torrefied biomass (3%–20%) and coal fines (80%–97%) were blended together to produce the composite briquettes under a hydraulic press (28 MPa). The briquettes were cured at 300 °C. Density, water resistance, drop to fracture, impact resistance, and cold crushing strength were evaluated for the composite briquettes. The proximate, ultimate, and calorific value analyses were carried out according to different ASTM standards. Microstructural studies were carried out using scanning electron microscope and electron probe microanalyzer equipped with energy dispersive x-ray. Fourier Transform Infrared Spectrophotometer (FTIR) was used to obtain the functional groups in the raw materials and briquettes. The density of the composite briquettes ranged from 0.92 to 1.31 g/cm3 after curing. Briquettes with 95%). The highest cold crushing strength of 4 MPa was obtained for briquettes produced from 97% coal fines and 3% torrefied biomass. The highest drop to fracture (54 times/2 m) and impact resistance index (1350) were obtained for the sample produced from 97% coal and 3% torrefied biomass. The fixed and elemental carbons of the briquettes showed a mild improvement compared to the raw coal. The peaks from FTIR spectra for the briquettes shows the presence of aromatic C=C bonds and phenolic OH group. The composite briquettes with up to 20% torrefied biomass can all be useful as fuel for various applications.

Sawdust specimens of two Paulownia species, namely Paulownia tomentosa and Paulownia elongata, were evaluated in order to obtain briquettes and pellets. Briquettes and pellets were manufactured from the sawdust, and their physical properties (density), mechanical properties (the resistance of the briquettes to breaking, and the shear resistance of the pellets), and energetic properties (caloric value, black ash content, and calcined ash content) were determined. The densities of the P. elongata and P. tomentosa briquettes were 790 kg/m3 and 934 kg/m3, respectively, while the pellets had densities of 1268 kg/m3 and 1266 kg/m3, respectively. These values were within the standardized limits, and the ash content had good values. The high calorific value of 16815 kJ/kg and the low calorific value of 16669 kJ/kg was acceptable, since they were greater than other vegetable resources. In conclusion, it was found that the two types of wood biomass are suitable for the production of briquettes and pellets, due to their good physical, mechanical, and energetic properties.

In this paper, the carbonization of multilayer PET containing an oxygen barrier layer was investigated. The oxygen barrier layer was identified as MXD6 nylon, which is widely used in the beverage industry due to its excellent barrier properties but is difficult to be mechanically separated and unsuitable for recycling. Carbonization experiment was conducted using a 2.0-L batch reactor at 400–480 °C and residence time 2 h to investigate the effects of multilayer PET on carbonization product. Char, wax, and gas were obtained and evaluated in terms of calorific value, elemental analysis, surface analysis and compound identification. Data testify that char yield was approximately 20 wt% and char obtained from all runs had high carbon content with minimal effects from oxygen barrier layer. The results showed that oxygen barrier layer had no apparent effect in the char composition and characteristics, but produced more aromatic hydrocarbons such as biphenyl and fluorene in wax and more CO2 in gaseous product.

Thermal processing (torrefaction, pyrolysis, and gasification), as a technology can provide environmentally friendly use of plastic waste. However, it faces a problem with respect to its by-products. Pyrolysis oil obtained using this technology is seen as a substance that is extremely harmful for living creatures and that needs to be neutralized. Due to its relatively high calorific value, it can be considered as a potential fuel for internal combustion spark-ignition engines. In order make the combustion process effective, pyrolysis oil is blended with ethanol, which is commonly used as a fuel for flexible fuel cars. This article presents results from combustion tests conducted on a single-cylinder research engine at full load working at 600 rpm at a compression ratio of 9.5:1, and an equivalence ratio of 1. The analysis showed improvements in combustion and engine performance. It was found that, due to the higher calorific value of the blend, the engine possessed a higher indicated mean effective pressure. It was also found that optimal spark timing for this ethanol-pyrolysis oil blend was improved at a crank angle of 2–3° at 600 rpm. In summary, ethanol-pyrolysis oil blends at a volumetric ratio of 3:1 (25% pyrolysis oil) can successfully substitute ethanol in spark-ignition engines, particularly for vehicles with flexible fuel type.