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Development of sorbent compositions from industrial waste is a promising and economically feasible method for solving environmental problems. Power industry enterprises experience an acute need for the development of new environmentally friendly and cheap sorbents for gaseous fuel desulfurization purposes. Owing to removal of sulfur compounds from the fuel, the latter becomes less corrosive in nature, due to which it becomes possible to increase the equipment's service life and also to decrease the deposits of sulfides on the surfaces of power installations. Based on a review of literature sources, the most important developments for sorbents consisting of industrial waste were determined. The waste of a thermal power plant (TPP) water-treatment facility (WTF) in the form of sludge water is of the greatest interest for removing sulfur compounds from fuel. Sludge water has a complex composition, which depends directly on the source water quality and water-treatment technology. Sludge water is produced at the natural water pretreatment stage, during which suspended matter is removed from source water by adding coagulants, flocculants, and other chemical agents that are specified by the process regulation. The article presents the composition of a sorbent produced from the WTF sludge at one of the Kazan combined heat and power plants (CHPP) for gaseous fuel desulfurization. Laboratory experiments were carried out with this sorbent, as a result of which the sulfur compound absorption efficiency and the strength characteristics of the prepared and formed sorbent were determined. A new method for indicating the extent to which the adsorbent absorption efficiency is decreased by using an indicating sorbent is also proposed. It is very difficult to monitor the level of sulfur compounds in purified gas by means of automatic sensors in view of a high measurement error, due to which an inaccurate result is obtained. An indicating sorbent composition that makes it possible to detect nonadsorbed sulfuric compositions by showing a color change from light to deep yellow is proposed. A method for using this indicating sorbent is described, and experimental data on its ability to absorb sulfur compounds are given. [ABSTRACT FROM AUTHOR]

Topics related to fuel combustion and its impact on the environment will never lose their relevance, as the issues of efficient combustion and emission reduction are key in power generation and environmental protection. The countries of the European Union are massively abandoning the use of natural gas as a fuel for thermal power stations. However, in Asian countries, the ease of using natural gas as the main fuel and its environmental friendliness compared to coal made it possible to widely use natural gas in industry and energy sector. Comparing natural gas with alternative combustible gases (generator, blast furnace, mine, biogas), the main conclusion that it has the most attractive characteristics for its use in industry, including energy facilities, can be drawn. Therefore, it is impossible to replace it with alternative fuels in the chemical, heavy industry and energy sector in the near future. The paper is devoted to CFD modeling of stabilized combustion without premixing in a burner with low swirl for two operating modes of the boiler unit - nominal one and at 60% capacity. The study was carried out using numerical methods with the ANSYS-Fluent application program package. The object of the study is a burner built according to the technology based on the use of jet-niche systems with gas distribution of fuel by circular jets fed perpendicularly into the flow of the oxidizer through a single-row system of holes. Hydrodynamics and heat exchange processes were chosen as the subject of research, based on the analysis of which a model of NOx generation in jet-niche systems was obtained. The authors of the paper believe that replacing the regular burners of the DKVR-10-13 water heating boiler with a jet-niche ones can contribute to better mixing of fuel and air and ensure more complete combustion. In this paper, two types of burners are considered. In one of the burners, fuel is supplied through rectangular slits, in the other – through round holes arranged in a row. Air is supplied to both burners through rectangular slits. It was determined that gas distribution through round holes increases the spraying of the mixture and increases the area of combustion products spraying. Visualization of the distribution of pressure, temperature, kinetic energy profiles of turbulent pulsations and vorticity was carried out. The obtained results indicate that there are no changes in the flow regime, flame displacement or its instability. It was determined that both the axial velocity and the tangential velocity of the flow affect the distribution of combustion products and harmful impurities such as NOx. Gas distribution in circular jets stabilizes combustion and reduces flame expansion.

Methane Number (MN) is a fuel rating technique for gaseous fuels analogous to Octane Number. This study establishes and shares a repeatable and reproducible method for MN determination of a gaseous fuel using a modified Cooperative Fuel Research Engine (CFR). Adaptations required to convert a CFR engine for use in the MN test procedure are identified. The investigation includes allowable environmental parameters and operating variation limits. An essential aspect of the MN method involves identifying and quantifying Knock Intensity (KI) during engine operation. CFR engines, originally designed for gasoline testing, come equipped with their own knock measurement systems utilizing a capacitive detonation sensor. The original system is compared with a Fast Fourier Transform (FFT) approach that uses a piezoelectric pressure transducer. Quantification of methane number requires an accurate assessment of the reference fuel blend (CH4 + H2). A comparison is carried out between dynamic blending using mass flow meters and bracketing using certified gas bottles containing various CH4/H2 blends from a gas supplier. [ABSTRACT FROM AUTHOR]

This paper presents the results of laboratory experiments to study the effect of the consumption of gaseous fuel (natural gas) supplied into a sintered charge layer on sintering process indicators and sinter quality under the charge conditions of the Ural Steel Company at charge layer heights of 350 to 500 mm. It was established that an increase in the consumption of natural gas supplied to the sintered charge layer in the range from 3 m3/t to 7 m3/t of sinter increases the vertical sintering rate, yield, specific productivity, and strength properties of the sinter. The benefit of supplying gaseous fuel to the layer is due to improvement in the temperature-time conditions of sintering, which increases the degree of involvement of the charge ore in the processes of melt formation and ensures a more complete use of solid fuel at lower consumption. The efficiency of supplying gaseous fuel to the sintered charge layer increases substantially with increasing sintered layer height because of a decrease in the proportion of the upper part of the sinter, which is formed under less favorable thermal conditions. According to the totality of indicators, considering the cost of natural gas, its optimal consumption in the charge conditions of the Ural Steel Company is 3.0 m3/t of sinter, which ensures the maximum increase in sintering indicators and sinter quality compared with traditional sintering technology. [ABSTRACT FROM AUTHOR]

• Catalyst-free approach for a technologically advantageous pyrolysis. • Two-stage plant to optimize gas yield (∼65 % w/w) and calorific value (∼41 MJ/kg). • Pyrolytic gas has potential for replacing fossil fuel in combustion engine. • Integration with combustion engine is promising for electricity and thermal power. In response to the escalating global challenge of mounting plastic waste and the imperative to adopt more sustainable practices for resource utilization, our study focuses on the utilization of plastic solid waste (PSW) through a two-stage thermal pyrolysis process. This aims to demonstrate its potential as a high-performance alternative to existing two-stage catalytic pyrolysis methods. The experimentation involved processing real scrap PSW material in a lab-scale batch set-up, emphasizing optimizing residence time in the cracking reactor to maximize gas yield and its lower heating value (LHV). The study underscores the advantages of the employed two-stage thermal pyrolysis apparatus through a comparative analysis with established set-up dedicated to maximizing gas yield. Once the operative conditions were explored, resulting pyrolysis products underwent detailed characterization to assess their suitability as a sustainable fuel source. The study also presents a practical application of the produced gaseous fuel, envisioning its combustion in an internal combustion engine (ICE), known for its flexibility regarding fuel properties. This application is demonstrated through a simulation conducted in Unisim Design©. The successful processing of real PSW material in the two-stage lab-scale experimental set-up showcased optimal gas yield achievements (>65 % w/w) with an LHV (∼41 MJ/kg), comparable to that of natural gas. This emphasizes the potential of these sustainable alternatives to replace fossil fuels, especially in the context of ICE applications. The integration of the pyrolysis plant with an ICE demonstrated promising prospects for generating electricity in the transportation sector and facilitating thermal power for heat integration in pyrolysis reactors. [ABSTRACT FROM AUTHOR]

Chemical looping combustion (CLC) is a promising combustion technology due to its low-energy penalty and the ability for 100% CO2 capture. CLC at nanoscale is emerging as a favorable option for the gas-fired power plants in recent times because of the inherent advantages of the nanostructured oxygen carriers (OCs). However, the cyclic stability at high transition metal oxide loadings of OCs is crucial in the successful adoption of this technology. At high temperatures, severe sintering is a major concern for these nanostructured OCs. In this work, Fe2O3/Al2O3 (60:40) composite nanostructured OCs with fibrous morphology are synthesized using electrospinning technique. These synthesized OCs are tested for their redox cyclic stability at 900 °C under CLC atmosphere with CO as fuel in tubular fixed-bed reactor. The morphological changes of these OCs are evaluated after 10 and 20 redox cycles. The analysis of the characterization results revealed that the synthesized nanofibrous OCs even with high transition metal oxide loading exhibited remarkable sintering resistance compared to the composite nanoparticles under similar conditions. [ABSTRACT FROM AUTHOR]

Hydrogen and methane as secondary fuels in diesel engines can be promising solutions to meet energy demand. The current study investigated the effect of the specialty gases of different compositions on diesel engine performance and exhaust gases. Four gases with various compositions of exhaust gas recirculation (Carbon monoxide, Carbon dioxide, and Nitrogen) and fuels (Hydrogen and Methane) were used at various mass flow rates of 10, 20, and 25 LPM (liter per minute), and various engine speeds of 2000, 2500, 3000, and 3500 rpm (revolutions per minute). The procured results revealed that adding specialty gases improved brake thermal efficiency and power. Similarly, the brake-specific fuel consumption was also massively retarded compared to diesel due to the influence of the hydrogen and methane composition. However, the fuel with the higher nitrogen reported less BTE (brake thermal efficiency) and comparatively higher exhaust gas temperature owing to the higher presence of nitrogen in their composition. Regarding emissions, including exhaust gas recirculation dropped the formation of pollutants efficiently compared to diesel. Among various fuels, Case 1 (30 % H2, 5 % CH4, 5 CO2, and 60 % CO) reported the lowest emission of NOx, and Case 2 (25 % H2, 5 % CH4, 5 CO2, 30 % CO, and 35 % N2) of CO and CO2 emissions. Generally, specialty gases with a variable composition of exhaust gas recirculation gases can be a promising sustainable replacement for existing fossil fuels.

This work experimentally investigates the flame interaction (flame merging and flame height), gas temperature distribution, and radiative heat flux from two rectangular propane burners by varying total heat release rate (80–360 kW) and burner spacing (0–1.28 m). The results show that the dominant mechanism of air entrainment rate changes from spacing to heat release rate with increasing spacing, making two flames from fully merging to non-merging. A method for predicting the flame height is proposed in terms of air entrainment mechanism, which is proportional to the 2/3 power of the group dimensionless parameter (Q˙total*,Q˙total*=Q˙totalρ0CpT0g1/2LP3/2). With the decrease of spacing, gas temperature in the additional region is distributed in an inverted U-shaped manner in the horizontal direction, reaching its extreme value at the center of the two burners. The vertical gas temperature can be employed to estimate the critical flame merging, which depends on the dimensionless parameters of Q˙total* and S/W. When S/W

Conventional fossil fuels are being substituted with alternative green fuels because of their greenhouse gas emissions and pollution problems, which pose a severe threat to the environment. Several studies have reported the usage of biodiesel and gaseous fuels in both single and dual-fuel modes. Gaseous fuels such as producer gas, biogas, syngas, and hydrogen produced from renewable biomass could potentially be used along with biodiesel in dual-fuel engines. Still, these are the least investigated in terms of their use as potential energy carriers. This review article encapsulates the viability as well as the impact of various gaseous fuels, including producer gas, biogas, compressed natural gas, liquefied petroleum gas, syngas, and hydrogen, in dual-fuel mode diesel engines with the aim of evaluating the performance, emission, and combustion behavior at various induction as well as operational parameters. Considering emission behaviors of diesel engines fueled with producer gas, biogas, compressed natural gas, and hydrogen, it is found that hydrocarbon and carbon monoxide emissions increase in the range 17.5–31.4% and 11.73–23.6%, respectively. On the contrary, oxide of nitrogen and smoke opacity tend to reduce from 14.3 to 18.2% and 21.4%36.5–63.7%, respectively. Moreover, there is a slight deterioration in performance characteristics for diesel engines fueled with producer gas, biogas, compressed natural gas, and hydrogen in the range of 2.1–8.84% for brake thermal efficiency, and 3.1–7.3% for brake-specific energy consumption. In addition, the combustion characteristics of gaseous fuels is also discussed in detail. Moreover, a SWOT analysis has been carried out with an emphasis on possibilities for usage of gaseous fuels in dual-fuel diesel engines. Finally, the limitations and perspectives of using gaseous fuels are also critically presented. • Key applications of gaseous fuels to dual-fuel engines were critically presented. • Performance and emission of engines running on gaseous fuels were scrutinized. • Engines powered by gaseous fuels could increase global energy consumption. • NOx and greenhouse gas emissions could be remarkably reduced by using gaseous fuels. • SWOT analysis for gaseous fuels was discussed in detail. [ABSTRACT FROM AUTHOR]

The paper considers the conversion of an aircraft combustion chamber with a two-level arrangement of injectors to natural gas. The design features of the aircraft combustion chamber and the combustion chamber using the natural gas are considered. The structural elements that have been modified are given. A design changes for ensuring operation on natural gas are rationalized. [ABSTRACT FROM AUTHOR]

Mixing of fuel and air is important for improving combustion performance and reducing pollution emissions. To improve the mixing performance of gaseous methane and air, the typical flame stabilizer was modified. A numerical study was conducted to compare the mixing and combustion performance of the mixing-enhanced flame stabilizer with the original one, and the mixing enhancement mechanism was clarified. The results show that the mixing performance of the mixing-enhanced flame stabilizer is improved in two ways. On the one hand, the disturbance of the gas fuel jet in the recirculation zone promotes the mixing of fuel and air. On the other hand, the velocity gradient between the recirculation zone downstream the bluff body and the mainstream decreases, which allows more fuel to enter the recirculation zone downstream the bluff body. This study is expected to promote the rapid mixing of gaseous fuel jets and the flame stability of the combustion chamber based on bluff body stabilizers.

The results devoted to the issues of energy-ecological assessment of industrial boiler equipment with jet-niche combustion technology are given in the paper. The basic principles underlying this technology include: rational distribution of fuel in the oxidant stream; stable adjustable structure of fuel, oxidant and combustion products; self-regulation of the fuel mixture composition in the zone of the torch stabilization when the unit load changes. As of today, a large number of industrial gas-burning equipment has been modernized by jet-niche technology, including: boilers, furnaces, dryers, metallurgical facilities, etc. The results of industrial implementation of the technology allowed to accumulate a significant amount of technical information and gave the possibility of preliminary environmental assessment during the modernization of gas combustion equipment. As practice shows, at the present stage the main direction of the technology improvement is to enhance its environmental performance. The influence of the main regime and technical parameters of fire equipment on its emission indicators is established in the paper. Possibilities for reducing nitrogen oxides by primary technological methods, the simplest and most effective of which is the introduction of recirculation gases into the furnace space, have been identified. According to the results of the analysis of emission indicators of the modernized fire equipment with a capacity of 0.5–60 MW, data to estimate the emission indicators of low and medium power boilers depending on the main influencing factors, namely, unit size, excess air ratio and boiler load were obtained. The influence of the introduction of recirculation gases into the furnace space on the level of nitrogen oxides concentration is also taken into account. The efficiency of application of the recirculation gases introduction scheme into the primary air flow in comparison with combustion technologies based on vortex burners is shown. According to the results of the industrial experiment, the energy efficiency of the proposed measures was established on the example of the dependences of efficiency on the load of boilers PTVM-50 and KVGM-20.

The greenhouse problem has a significant effect on our communities, health, and climate. So, the capturing techniques for CO2 remain the focus of attention these days. In this work, a Chemical Looping Combustor (CLC) was designed and fabricated with the major geometric sizes at the Faculty of Engineering, Suez Canal University. The system involves two interconnected fluidized beds. Nickel powder with 150 µm diameter as well as brown coal and liquefied petroleum gas were used as oxygen carrier, solid fuel, and gaseous fuel, respectively. The temperature distributions along the fuel reactor for LPG flow rates of 11 and 18 LPM with and without using nickel powder as well as using preheated reactor were discussed and evaluated. The effects of brown coal diameter change with and without using nickel powder were studied. The CO and CO2 concentrations at combustion gases with and without using nickel powder were conducted for LPG and brown coal fuels. A mathematical model was used to simulate the combustion in CLC using combustion and energy code. The obtained results showed that using nickel powder improved the combustion process and in case of using LPG, the flame color changed to blue which is the color of the complete combustion flame. The CO was reduced by 48.4 % and CO2 was augmented by 66.5 %. In case of using brown coal as solid fuel, CO was reduced by 53.7 % and CO2 was increased by 71.9 %. Finally, there is good agreement between the experimental and numerical results based on the determination coefficient.

Nowadays, there is a global trend towards the use of alternative fuels in order to reduce environmental pollution. For example, Compressed Natural Gas (CNG) has become more widely used around the world. The use of different fuels in engines affects the combustion process and efficiency, with the latter potentially being reduced by such means as, for example, the use of gaseous fuels in conventional diesel engines. Therefore, it is also important to know how CNG combusts in a diesel engine and how the combustion process can be improved. Consequently, the aim of the study is to give an overview of the effect of divided Diesel Fuel (DF) pilot injection on the combustion process of a naturally aspirated diesel engine using dual-fuel mode, with one fuel being DF and the other CNG. The focus of the article is on the commonly used engines on which the diesel injection system works regularly, and CNG fuel is injected into the intake manifold as an additional fuel. The engine DF quantity and injection timing are regulated by the acceleration pedal. The article provides an overview of the diesel and dual-fuel combustion process, and compare the DF and dual-fuel combustion processes. For this purpose, a test was carried out in order to measure the various involved parameters, such as the combustion pressure, torque, and fuel consumption. The results demonstrated that ignition delay does not significantly vary with the use of gas as a fuel source, and the maximum combustion pressure is actually higher with gas. The combustion is more rapid in dual-fuel mode and results indicate that when using dual-fuel mode on regular engines, it would be necessary to regulate the pre- and main-injection timing.

Nowadays, there is a global trend towards the use of alternative fuels in order to reduce environmental pollution. For example, Compressed Natural Gas (CNG) has become more widely used around the world. The use of different fuels in engines affects the combustion process and efficiency, with the latter potentially being reduced by such means as, for example, the use of gaseous fuels in conventional diesel engines. Therefore, it is also important to know how CNG combusts in a diesel engine and how the combustion process can be improved. Consequently, the aim of the study is to give an overview of the effect of divided Diesel Fuel (DF) pilot injection on the combustion process of a naturally aspirated diesel engine using dual-fuel mode, with one fuel being DF and the other CNG. The focus of the article is on the commonly used engines on which the diesel injection system works regularly, and CNG fuel is injected into the intake manifold as an additional fuel. The engine DF quantity and injection timing are regulated by the acceleration pedal. The article provides an overview of the diesel and dual-fuel combustion process, and compare the DF and dual-fuel combustion processes. For this purpose, a test was carried out in order to measure the various involved parameters, such as the combustion pressure, torque, and fuel consumption. The results demonstrated that ignition delay does not significantly vary with the use of gas as a fuel source, and the maximum combustion pressure is actually higher with gas. The combustion is more rapid in dualfuel mode and results indicate that when using dual-fuel mode on regular engines, it would be necessary to regulate the pre- and main-injection timing. [ABSTRACT FROM AUTHOR]

• Higher ammonia concentrations lead to a notable increase in in-cylinder pressure, enhancing combustion efficiency. • Use of ammonia enhances the engine smoothness across various load conditions. • Direct correlation between increased ammonia concentration and HRR is noted. • Highest BTE was observed mainly due to increased ammonia concentration. • Increase in ammonia content also leads to higher NOx emissions. This study investigates the potential of ammonia as a secondary fuel in diesel engines, amidst the rising interest in alternative fuels and the growth of electric vehicles. Unlike hydrogen, with its higher flammability and safety concerns, ammonia offers a viable, sustainable fuel source. A single-cylinder diesel engine was utilized to assess engine performance and combustion characteristics using ammonia gaseous blends. Ammonia was combined with biogas to mitigate its corrosive effects and compensate for its lower heating value. Th entire best conducted with constant ammonia flow rate of 30 LPM. Diesel was mixed with biogas in compositions of 10 LPM, 20 LPM and 30 LPM, and tested under engine loads of 25%, 50%, 75%, and 100%. The blend with the highest ammonia concentration (B30B3) exhibited the largest heat release rate, highlighting a strong correlation between ammonia content and heat release levels. This is attributed to the premixed combustion phase and the accelerated flame speed associated with ammonia. An increase in ammonia content resulted in higher brake thermal efficiency and reduced brake specific fuel consumption. All ammonia-inclusive blends showed a decrease in hydrocarbon and carbon monoxide emissions, with the lowest emissions observed in the B30B3 blend. However, the high flammability of biogas in the B30B3 blend, compared to diesel, and enhanced fuel atomization, led to increased nitrogen Oxides formation. The results clearly indicate that combination of ammonia along with the biogas enhances the combustion and reduces greenhouse gas emissions. Findings of this study provides valuable insights into the use of ammonia as a sustainable alternative in diesel engines, offering a improved balance between combustion efficiency and environmental impact. [ABSTRACT FROM AUTHOR]

The paper presents results of SI engine tests, carried on for different gaseous fuels. The analysis carried out made it possible to define the correlation between fuel composition and engine operating parameters. Tests cover various gaseous mixtures: methane with hydrogen and LPG with DME. The first group, considered as low carbon content fuels, can be characterized by low CO2 emissions. The flammability of hydrogen added in those mixtures realizes the function of combustion process activator and improves the energy conversion. The second group of fuels is constituted by LPG and DME mixtures. DME mixes perfectly with LPG and differently than in the case of other hydrocarbon fuels also consisting of oxygen, which makes the stoichiometric mixture less oxygen demanding. In the case of this fuel, improvement in engine volumetric and overall engine efficiency has been noticed, compared to LPG. During the tests, standard CNG/LPG feeding systems have been used, which underlines the utility value of the research.

During the past decades, the diesel engine has been through times of upheaval, boom and bust. At the beginning of the century, almost 50% of the new vehicle registrations in the European market were diesel-powered. However, the news of deadly diesel NO x emissions supported by the diesel emission scandals caused a shock to the diesel engine market, and the sustainability of the diesel engine is currently in dispute. Recently major automotive manufacturers announced the development of diesel-powered vehicles with negligible NO x emissions. Moreover, the NO x emissions production is of lower concern for heavy-duty, marine or power generations applications where the implementation of advanced aftertreatment systems is feasible. However, despite the tackle of NO x emissions, the decarbonisation of the automotive, marine and power generation markets is mandatory for meeting greenhouse gas emissions targets and limiting global warming. The decarbonisation of the diesel engine can be achieved by the implementation of a carbon-free fuel such as ammonia. This paper provides a detailed overview of ammonia as a fuel for compression ignition engines. Ammonia can be combusted with diesel or any other lower autoignition temperature fuel in dual-fuel mode and lead to a significant reduction of carbon-based emissions. The development of advanced injection strategies can contribute to enhanced performance and overall emissions improvement. However, ammonia dual-fuel combustion currently suffers from relatively high unburned ammonia and NO x emissions because of the fuel-bound nitrogen. Therefore, the implementation of aftertreatment systems is required. Hence, ammonia as a compression ignition fuel can be currently seen as a feasible solution only for marine, power generation and possibly heavy-duty applications where no significant space constraints exist. • A comprehensive review of ammonia for compression ignition engines. • Ammonia dual-fuel combustion can contribute to significant CO and CO 2 reduction. • Ammonia CI engines suffer of high unburned NH 3 and NO x emissions. • Advanced injection strategies can improve engine performance and emissions. • Aftertreatment systems are mandatory for the adaptation of this technology. [ABSTRACT FROM AUTHOR]

Polyethylene dust and polypropene dust were selected to measure the minimum explosion concentration in three kinds of gaseous fuel environments. The results show that the MEC of polyethylene dust with higher apparent activation energy decreased more significantly, and the plastic dust showed higher explosion sensitivity for the gaseous fuel with high combustion heat. The explosion mechanism for plastic dust in gaseous fuel environments was proposed with the global reaction kinetics of plastic pyrolysis, and it suggests that the gaseous fuels reduce the apparent activation energy of plastic dust and provide additional heat for the plastic dust explosion. A corresponding prediction model for the minimum explosion concentration of plastic dust was established. The new model has good applicability for the data obtained in this work and the data in the previous reference. [Display omitted] [ABSTRACT FROM AUTHOR]

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Abstract Chemical looping combustion (CLC) is an advanced oxyfuel process that enables CO 2 capture with low efficiency penalty. CLC of gaseous fuels has successfully been demonstrated in several pilots up to 150 kW th. Numerous oxygen carriers have been tested regarding fuel conversion performance and lifetime. This work is a scale-up study of gaseous fuel CLC to MW th scale. A Ca-Mn-based oxygen carrier has been developed and manufactured in ton-scale prior to the present test. Investigations were conducted in a 1 MW th CLC unit that was adapted to utilize natural gas as fuel. Stable CLC conditions were reached during tests with Ca-Mn-based material, and the transition to operation with ilmenite was studied. The fuel conversion was in the range of 80%. During operation, 99% of the unburned methane was converted in the post oxidation chamber. The solids circulation rate and the lifetime of solids were determined by means of solids samples from the process, which were investigated in terms of attrition and degree of oxidation. The solids circulation rate was 17 tons h−1 MW−1 which is higher than in former tests but lower compared to other units. The most important limiting factors of the fuel conversion are the low solids inventory of the fuel reactor and the oxygen carrier to fuel ratio that corresponds to the solids circulation. [ABSTRACT FROM AUTHOR]

The exploitation of fossil fuels has led to the emerging of gaseous fuel for the automobile engines. The researchers are in the search of producer gas from forest woods. In the process of bio gasification, tar is the major obstacle to produce high efficiency gaseous fuel. In this research work, a catalytic tar mitigation process is framed with nickel (Ni) based catalyst. The Ni based nano Si and Ti catalysts are synthesized using deposition-precipitation method. The synthesized Ni-Si and Ni-Ti catalysts are characterized using scanning electron microscope (SEM) and transmission electron microscope(TEM). The surface area and pore volume are calculated by Brunauer-Emmett-Teller and Barrett-Joyner- Halenda methods to justify the catalytic active surface. A design of experiments (DoE) is framed with L12 design table for the 2 level factors (catalyst, catalyst weight, bed temperature and gas feed rate) for the tar concentration response. The signal to noise (SN) ratio and mean of the factors are analysed to identify the significance. As the outcome of the statistical analysis, it is concluded that the minimum tar concentration of 0.47(mg/Nm³) is attained for the 10% of Ni-Si catalyst with the bed temperature of 800°C and gas feed rate of 0.01 l/s. [ABSTRACT FROM AUTHOR]

Multiple fires burning in a windy environment is a special fire phenomenon when multiple flames from separate fuel sources burn simultaneously within a certain space range. It is commonly observed in urban, industrial fires and wildland. To improve the fire safety and achieve optimum energy management, it is important to study the combustion characteristics of multiple fires in wind. This paper investigates the characteristics of flame merging and tilt angle. Twin propane burners aligned parallel to the cross wind with the same energy (heat) release rate were used as energy sources. The experimental results show that with increasing spacing there are three categories of flame merging characteristics, i.e., continuous merging, intermittent merging and non-merging. A new mathematical methodology is introduced to quantify the flame merging possibility in the presence and absence of wind, in counteracting the limitation and uncertainty in traditional method due to the fact of extensive vibration nature of the flames in a wind. Based on the momentum-balance equation, a piecewise function of the flame tilt angles is established in different merging states. Finally, the proposed formulae of flame tilt angles are validated using the literature and experimental data, which show the broad applicability. • Experiments were conducted for two propane fires aligned parallel to cross wind. • A new methodology is introduced to quantify the flame merging possibility. • A piecewise function of the flame tilt angle is established. [ABSTRACT FROM AUTHOR]

The processes of burning a gaseous fuel in the furnace of the DE-10/14 steam water-tube boiler have been investigated numerically. The temperature and velocity distributions of the gases in the furnace space of the boiler, as well as the concentrations of combustion components have been determined. It has been shown that placing a secondary radiator along the horizontal axis of the burner in the furnace space of the boiler promotes the formation of a uniform temperature field along the length of the furnace and a decrease in the temperature in its space, and the reverse flow of combustion products to the combustion front provides a decrease in the concentration of nitrogen oxides to 123–125 mg/m3 at the furnace outlet. [ABSTRACT FROM AUTHOR]

The paper presents results of SI engine tests, carried on for different gaseous fuels. The analysis carried out made it possible to define the correlation between fuel composition and engine operating parameters. Tests cover various gaseous mixtures: methane with hydrogen and LPG with DME. The first group, considered as low carbon content fuels, can be characterized by low CO2 emissions. The flammability of hydrogen added in those mixtures realizes the function of combustion process activator and improves the energy conversion. The second group of fuels is constituted by LPG and DME mixtures. DME mixes perfectly with LPG and differently than in the case of other hydrocarbon fuels also consisting of oxygen, which makes the stoichiometric mixture less oxygen demanding. In the case of this fuel, improvement in engine volumetric and overall engine efficiency has been noticed, compared to LPG. During the tests, standard CNG/LPG feeding systems have been used, which underlines the utility value of the research. [ABSTRACT FROM AUTHOR]

• Sustainable production methods for hydrogen and ammonia were reviewed. • Hydrogen storage need massive development before its commercialization. • Gaseous fuels such as hydrogen and ammonia on compression ignition engines has been examined. • Hydrogen and ammonia enhance both engine performance and combustion characteristics. • Significant raise in the NOx reported due to cylinder temperatures. Renewable energy resources have been recognized as one of the promising sources of energy to meet the current energy demand without affecting the environment. Hydrogen and ammonia fuels are being explored as sustainable energy sources to replace fossil fuels. Green fuels have gained profound attention due to their environmentally friendly nature and human health concerns. Although these fuels are sustainable on a laboratory scale, implementing them on a commercial scale is still in the early stages of development. Numerous studies have reported the effectiveness of hydrogen and ammonia in diesel engines as efficient energy carriers. However, although previous research shed light on these fuels, their economic viability is still a concern. This review provides an in-depth analysis of hydrogen and ammonia production methods. Additionally, the effect of blends on diesel engines was determined by comparing the obtained data through performance, combustion, and emission characteristics. Parameters such as brake thermal efficiency, brake-specific fuel consumption, exhaust gas temperature, heat release rate, in-cylinder pressure, carbon monoxide, carbon dioxide, hydrocarbon, nitrogen oxides, and particulate matter were observed. The effects of noise and vibration resulting from the addition of hydrogen, ammonia, and biodiesel blends were also discussed in detail. Increasing the concentration of hydrogen and ammonia increases the formation of pollutants and reduces brake thermal efficiency. On the other hand, increasing the concentration of biodiesel decreases pollutants such as CO, HC, and CO 2 , but there is an increase in NOx. Based on the findings, it is evident that hydrogen and ammonia can be effective sources of energy to replace fossil fuels, and their production methods and usage need to be further optimized to achieve economic and societal benefits. [ABSTRACT FROM AUTHOR]

There are many ways of recycling wood and its waste into energy. But one of the most perspective is gasification. Therefore, the technology of thermal recycling of wood fuel in gaseous fuel is an urgent problem to be solved. Consequently, our objective is to find the dependence of net calorific value of synthesis gas from the amount of air, humidity and particle size of chopped wood, which is fed into the gasifier. For the experimental research and development process of gasification of wood in gaseous fuel a gasifier with a continuous layer is designed. In the process of of experimental research the author used a mix of wood (willow (Salix alba L.) in the amount of 1/3 of the total weight of the mixture, Pine (Pinus sylvestris) – 1/3 of the total weight of the mixture, birch (Betula pendula Roth.) – 1 / 3 of the total weight of the mixture). From experimental data we have evaluated the most optimal parameters gasification process of mixes wood, when net calorific value of synthesis gas reaches its maximum. We also obtained mathematical description of the object in a second order polynomial. To conclude, completed rationalization derived dependence to determine the values of the factors that ensure the maximum Q = 10.4 MJ / nm3, namely the size of the particles of wood l = 36 mm, the amount of air G = 68 nm3 / h, a mixture of wood humidity W = 34 %. The experimental data show that the experimental gasifier enables gasifying wood, at low and high humidity (50 %); while the gas generators for the industrial impact of humidity on the process of gasification is significant. Therefore, the results of theoretical and experimental researches should determine the technical parameters of the gas generator installation with the definition of rational parameters of the process: particle size and humidity of chopped wood, the amount of air that is fed into the gasification chamber and to develop practical recommendations for thermal recycling of wood.

In this study, we focused on premixed charge compression ignition (PCCI) combustion with dual fuel of carbon monoxide (CO) and diesel fuel. The effects of CO as fuel on PCCI combustion characteristics were investigated based on engine tests and numerical simulations. As a result, it was found that the combustion became mild and combustion phase was retarded with increasing amount of CO supply. The results suggest that the combustion phase can be controlled by optimizing amount of CO supply, and moreover that the operating regions of PCCI combustion will be extended. In addition, it became clear that the supply of CO on PCCI combustion could be an alternative method for introducing large amount of EGR and lowering the compression ratio. On the other hand, the supply of CO led to an increase in unburnt CO emission and a deterioration in thermal efficiency. The numerical simulation results showed that it is effective to simultaneously increase the effective compression ratio and the EGR ratio in order to overcome these disadvantages without increasing NOx emission. Therefore, there is a possibility that PCCI combustion with dual fuel of CO and diesel fuel will possibly achieve high thermal efficiency.

The existing structure of the fuel balance in Ukraine does largely determine high prices of such energy products as the electricity and the heat. The main reason lies in the fact that approximately 40% of the fuel balance represents the expensive imported liquid and gaseous fuels. Of course, such balance structure significantly affects the energy security of Ukraine. The article analyzes the three main directions of this situation possible normalization: replacing the imported gas with relatively inexpensive domestic coal burned at boilers and innovative coal-fired burner systems, especially in the low-temperature boilers with fluidized bed furnaces; replacement of imported fuel with respectively cheap pyrolysis gas obtained from the domestic low-grade brown coal; organization of domestic production of shale gas, which industrial production is scheduled for 2020. These promising directions of the national energetics’ fuel balance development can be considered as a priority part of the national tasks of increasing the country’s energy independence.

In a Chemical Looping Combustion system, the fuel and air reactors are strongly coupled because of chemical reactions in both and the circulation of solid oxygen carrier between them. To capture the effects inside the system, a novel dynamic flowsheet simulation environment for solids processes is applied to Chemical Looping Combustion of methane. Flowsheet simulation is a tool for process analysis and optimization covering multiple process units and flows in a system. An experimental 25 kW th pilot plant is operated, and all of its process units are modeled. The modeling comprises three fluidized bed reactors, two operating in bubbling fluidized bed condition and one as a circulating fluidized bed riser. A cyclone is used for gas-solid separation after the air reactor. The loop seals ensure gas sealing between the reactors. Fluid mechanics inside the systems are modeled with empirical and semi-empirical correlations, to enable fast calculations. This approach becomes handy when long-term dynamic effects like abrasion, start-up, or shut-down procedures as well as load changes are to be modeled. Chemical reactions for a gaseous fuel and their implications on gas flows were implemented. In addition, oxidation and reduction of the solid oxygen carrier in the three reactors were part of the simulation. To validate the simulation results, the pilot plant was operated with methane as fuel. Gas measurements were taken after both stages of the fuel reactor. Additionally, solid samples were drawn from the hot facility to examine the oxidation state of the carrier, when fuel is introduced. A transient simulation of plant operation over a total runtime of 40 min reveals that the solids inventories of the fluidized bed reactors in the system need only 30 s in the present case to reach a new steady state after a load change. If the oxidation and reduction reactions of the oxygen carrier are taken into account, however, this response time extends dramatically to several hundreds of seconds, which can also be seen in the experimental campaigns. The simulation of such a system behavior requires a powerful simulation tool for flowsheeting, which has been found here in the dynamic simulation framework. [ABSTRACT FROM AUTHOR]

In this paper we formulate a model for the emission of Carbon Dioxide from gaseous fuel in Nigeria. We considered a third degree polynomial model using a least square method using the actual data set of twenty one years on State level Carbon Dioxide emissions in Nigeria from 1994-2014. The residual analysis was used to predict the short and medium term total Carbon Dioxide emissions trend. From the results the state of affairs of Carbon Dioxide Emission for subsequent years was forecast and this will help the Government to take control measures in curtailing the emission of Carbon Dioxide in the country. Keywords: Gaseous fuel, Automobile, Fossil fuels, Pollutants, Carbon Dioxide, Emissions

Biogas as a respected source of renewable energy is used in various areas for heating or in power cogeneration units. It is produced by anaerobic fermentation of biodegradable materials. The utilization of biogas is wide - from process of combustion in order to obtain thermal energy, combined heat and power production, gas combustion engines, micro turbines or fuel cells up to trigeneration. Biogas composition depends on the raw material. The aim of this paper was to develop a new methodology; according to this methodology, by means of gas mixture thermodynamics and tabular exact parameters of individual gaseous components, all the necessary thermodynamic and operating values of biogas composition were calculated. The mathematical model of biogas combustion was elaborated. For an accurate realization of calculation, a computing program was designed.

In this paper we formulate a model for the emission of Carbon Dioxide from gaseous fuel in Nigeria. We considered a third degree polynomial model using a least square method using the actual data set of twenty one years on State level Carbon Dioxide emissions in Nigeria from 1994-2014. The residual analysis was used to predict the short and medium term total Carbon Dioxide emissions trend. From the results the state of affairs of Carbon Dioxide Emission for subsequent years was forecast and this will help the Government to take control measures in curtailing the emission of Carbon Dioxide in the country. [ABSTRACT FROM AUTHOR]

Natural gas is employed to reduce coke consumption in cupola furnaces with an open or closed top. The usual approach here is combustion of the natural gas by means of burners in external chambers at the perimeter of the furnace housing. Depending on their design, the burners ensure partial or complete preliminary mixing of the gas and air, with an air excess of 1.2-1.5. Then the combustion products are sent directly to the batch bed. In this system, the coke consumption amounts to 8-9% of the metal charge, while the consumption of gaseous fuel is 30-40 m3/t of melt. In these conditions, the melt temperature rises slightly (by 10-20°C); the productivity is increased by 15-20%; and the harmful gas emissions (mainly CO) are reduced by 20-25%. The gas dynamics of the cupola furnace is periodically disrupted, with suspension of the batch bed, cooling of the melt produced, less complete chemical combustion, and damage to the furnace lining. When using this method, the gas-air mixture is supplied to the hot bed with an air excess no lower than 2.5-3.0. A high-temperature zone (1350-1380°C) of width 60-70 mm is formed and moves through the bed at a speed of 15-20 mm/min. This calls for uniform mixing of the gas and air, specific gas-dynamic conditions, and the creation of the required gas-air ratio, with an air excess of more than 2.5-3.0. If cold gas-air mixture is supplied to the furnace bed through a tuyere, the combustion zone divides the whole bed into two stages: the initial and final stages. The high temperature of the combustion zone ensures fast cooling of the material at ignition of the gas-air mixture. That prevents ignition in the space above the bed. The lack of direct contact between the high-temperature zone and the furnace's working space improves the reliability and economic indices of this process (no heat losses). Bed combustion of natural gas in the heating of such cupola furnaces increases the productivity from 10 to 13.6 t/h (by 36%), with reduction in coke consumption by 80 kg/t (33.3%) and decrease in heat consumption by 25 kW (18.78%). The heat losses with the exhaust gases are reduced by 25.32 kW (16.2%). The total thermal efficiency of the system is increased from 35.58 to 42.26% (by 15.81%, rel.). [ABSTRACT FROM AUTHOR]

Chemical looping combustion experiments have been conducted in the 150 kW CLC reactor at SINTEF Energy Research in Trondheim with good results. Methane was used as fuel and porous copper oxide based particles, with a bulk density of 800 kg/m 3 were, used as oxygen carrier. At a fuel power of 140 kW the methane conversion was limited to about 90%, but at 100 kW a methane conversion of up to about 98% was achieved with an oxygen deficit of about 3% compared to the stoichiometric amount. At the same time, the specific fuel reactor inventory was just above 120 kg/MW, which is low compared to data found in the literature. The total active inventory in both reactors together was then 44 kg and the overall excess air ratio was about 1.2. [ABSTRACT FROM AUTHOR]

Different CH4 and CO2 mixtures were used as fuel in this work; they were fed into a spark-ignited engine equipped with devices allowing spark advance, gas delivery and gas consumption to be measured. Engine bench-tests re-vealed changes in the main operation parameters and emissions. The results showed that increasing CO2 percen-tage in the mixture increased the spark angle, reduced maximum power and torque and reduced exhaust emissions (by 90% in some cases) when DAMA resolution 1015/2005 was applied. The main components to be considered when an engine of this type operates with gas fuel were also recognised.

We examine the results of the industrial implementation and operational experience of small ignition furnaces in sinter machines of various domestic and foreign enterprises. The furnaces are equipped with automatic thermal management systems. We assess the use of hot air both as input into the burners, as well as blown into the cake layer beyond the furnace. It is shown that the sintering gas recirculation, recovered after the vacuum chamber, can significantly reduce emissions into the atmosphere, reduce the consumption of solid fuels and the mass fraction of minutiae in the final agglomerate. We study different variants of organizing the recycling of sintering gas. [ABSTRACT FROM AUTHOR]

Biogas as a respected source of renewable energy is used in various areas for heating or in power cogeneration units. It is produced by anaerobic fermentation of biodegradable materials. The utilization of biogas is wide - from process of combustion in order to obtain thermal energy, combined heat and power production, gas combustion engines, micro turbines or fuel cells up to trigeneration. Biogas composition depends on the raw material. The aim of this paper was to develop a new methodology; according to this methodology, by means of gas mixture thermodynamics and tabular exact parameters of individual gaseous components, all the necessary thermodynamic and operating values of biogas composition were calculated. The mathematical model of biogas combustion was elaborated. For an accurate realization of calculation, a computing program was designed. [ABSTRACT FROM AUTHOR]

The gas leakage from a gaseous fuel pipeline usually leads to a jet fire, which causes both enormous loss of energy and thermal threat to the surrounding objects. The potential wild fire risk is a significant issue and need to be paid sufficient attention. This paper investigates the vertical flame height, horizontal flame length and provides a new mathematical method to quantify the trajectory of the flame produced by a linear buoyant turbulent jet fire, which can be resulted in due to pipeline fuel leakage, in cross air flows. Experiments are carried out by a 2 mm (width) ∗ 142.5 mm (length) line-source nozzle employing propane as fuel. The velocities of cross air flows are ranged from 0 m/s to 2.5 m/s. It is found that the vertical flame height and horizontal flame length can be well predicted by initial momentum ratio ( r ) and Froude number ( Fr ). A simple and easily applied explicit mathematical method is proposed to predict the trajectory length based on circumference approximation. All these findings can contribute to both combustion science and providing guidance for the wild jet fire risk assessment. [ABSTRACT FROM AUTHOR]