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The exhaust gas recirculation (EGR) valve regulates the exhaust gas flow between the engine exhaust manifold and the inlet one. This allows the inlet air to warm up, improving fuel evaporation and reducing the combustion temperature of the charge. Such a valve reduces the number of harmful substances in the exhaust gases. The valve tends to stick when too much sediment builds on the walls of the exhaust system, especially during driving in urban conditions or when leaks in the vacuum or exhaust pipes occur. A faulty valve causes the engine to run unevenly at idle speed and under light loads. The defective EGR valve weakens the inlet manifold capacity, increases combustion, causes clogging of the particulate filter and damage to the lambda probe. Blocked EGR valve may lead to engine immobilization as a result of its computerized control system operations. A model of an EGR valve for a selected diesel engine was developed to determine velocity distribution of the load flowing in it for different values of the degree of valve opening and the volume of deposits on the valve walls. The volume of accumulated carbon deposits on the walls of the EGR valve was measured using a real engine. Based on the recorded mileage of the vehicle, the assumed average speed of the car and the driving style of the driver and the intensity of deposition of carbon particles on the walls was estimated. [ABSTRACT FROM AUTHOR]

Biomass is an alternative and promising source for the sustainable production of energy and commodities such as hydrogen. For this, biomass can be converted into bioethanol through fermentation/hydrolysis that is reliably converted into hydrogen through steam reforming (SRE), and the performance of the most used catalysts for this process (Ni-based) is determined by the support components and preparation methods. In this work, three Ni-based catalysts have been compared for the SRE at 500 °C, steam/ethanol molar ratio of 3 and a low space-time of 0.025 h-1 in a fluidized-bed reactor: The catalysts tested were obtained upon reduction at 850 °C of a NiO/Al2O3 obtained by wetness impregnation (Ni-WI) and two spinel precursors (NiAl2O4 and NiMgAl2O4) prepared by co-precipitation (Ni-S and NiMg-S, respectively). The Ni-S and Ni-WI catalysts have similar performances with high ethanol conversion but unstable H2 yield over time on stream, whereas the NiMg-S catalyst has a higher and more stable H2 yield even with lower ethanol conversion, which proves differences in the prevailing reaction routes for the catalysts. The NiS and Ni-WI catalysts prompt the ethanol dehydration to ethylene (C2H4) on acid sites (which increases ethanol conversion) followed by its decomposition to carbon and H2, which are prevailing routes over SR reactions, thus producing significant amount of carbon deposits, although both carbon and H2 yield decrease suddenly after certain time on stream (TOS) due to deactivation of the C2H4 decomposition reaction. Conversely, the presence of MgO in the support of the NiMg-S catalyst neutralizes the acid sites and favors the ethanol steam reforming and ethanol dehydration to acetaldehyde (C2H4O), that is decomposed into CH4 and CO. An overall significant amount of carbon is also deposited upon NiMg-S catalyst (from CO and CH4 precursors) but it allows a stable behavior of the catalyst due to its filamentous nature. [ABSTRACT FROM AUTHOR]

• Hexamethylenediamine is a crucial intermediate for the production of polyamides. • HMDA was synthesized by 6-hydroxyhexanenitrile catalyzed amination reaction. • Catalyst Co 10 Ru 1 /MgO-γ-Al 2 O 3(0.3:1) was found to be good in the amination reaction. • The conversion of 6-HHN reached up to 100 %, with a HMDA yield of 38.14 %. • The total selectivity of HMDA, AHO and HMI of 86.92 %. Hexamethylenediamine (HMDA), which is a crucial intermediate for the production of polyamides and other chemical products, was synthesized from the reductive amination of 6-hydroxycapronitrile (6-HHN) derived from ε‑caprolactone (ε‑CPL) with aqueous ammonia as the ammonia source. A bimetallic catalyst Co 10 Ru 1 /MgO-γ-Al 2 O 3(0.3:1) -500 was found to be effective in the reaction. Over this catalyst the conversion of 6-HHN reached up to 100 %, with a HMDA selectivity of 38.14 %, corresponding to a yield of 38.14 %, and the total selectivity of HMDA, 6-amino-1-hexanol (AHO) and hexamethyleneimine (HMI) of 86.92 %. Characterization results disclosed that Co and Ru uniformly disperse on the surface of the MgO-Al 2 O 3 mixed-oxide support, and respectively acts as the dehydrogenation-hydrogenation active species in the reaction with seldom agglomeration either in catalytic run or regeneration process. It was also found that some nonvolatile carbonaceous substances deposited on the surfaces of the catalyst during a catalytic run, leading to the deactivation of the catalyst. The catalysis of the catalyst could be largely recovered by high temperature calcination to remove the carbon deposits, followed by reduction with H 2. [Display omitted] [ABSTRACT FROM AUTHOR]

The innovative system, which was developed for analysis and correction of motor management, is determined for the solution of practical problems concerning the operation of the piston combustion engines. Programming of the ignition curves and fuel maps without relevant feedback, namely, without information obtained from the engine operation, increases the risk of detonation combustion, which can destroy the combustion engine. However, the main application area of this system is the development of an algorithm, which is specified for control of the combustion process based on the HCCI technology (Homogenous Charge Compression Ignition). Nowadays, the functional principle of the HCCI engine is one of the most effective possibilities on how to reach higher operational efficiency of the gasoline engine, that is, closer to the efficiency level of the diesel driving units. [ABSTRACT FROM AUTHOR]

Methane is decomposed to carbon and hydrogen over Raney nickel catalyst in controlled manner in order to deposit carbon; and thereby NiC composite catalysts have been prepared. The catalysts have been analyzed by atomic emission spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The NiC catalysts are comprised of metallic nickel with superficial oxide and carbon. Electron density of Ni in the NiC catalysts is observed to be higher than that in the parent Raney nickel; this indicate partial charge transfer from carbon to nickel in the NiC catalysts. The NiC catalysts exhibite much better performance than the original Raney nickel catalyst in the selective hydrogenation of cinnamaldehyde to hydrocinnamaldehyde. They also exhibite stable performance in multiple reaction runs. [ABSTRACT FROM AUTHOR]

Highlights • Innovative carbon removal and performance restoring approaches. • Optimization of the regeneration methods. • Suggestions about commercial application of individual methods. • Lifetime extension proposal for SOFCs. Abstract Carbon deposition is one of the major degradation sources, which reduces the activity of solid oxide fuel cells (SOFC) and it can even cause irreversible cell degradation. In order to counteract this phenomenon and thus to extend the SOFC lifetime, development of effective cell-protecting strategies for carbon re-gasification and restoring of the cell performance is of crucial importance, since other methods considering prevention of this degradation phenomenon can mean an increased system complexity or reduced system performance. In the literature there is very limited data relating to the performance of SOFCs after the carbon removal process has been executed. This study aims to analyze carbon removal techniques and moreover their effect on the SOFC performance as well as possibilities for industrial application. Various innovative approaches for carbon re-gasification are scrutinized and detailed explained within this study on 20 samples, which further help to provide potential carbon removal procedures relevant for industrial SOFC systems. [ABSTRACT FROM AUTHOR]

One of the most frequently implemented processes in the water treatment technology is filtration through a biosorption bed. The techniques based on biochemical processes involving bacteria result in obtaining high quality of water. There are a number of different materials used as the filler material for biological filters. Carbon deposits are the most popular, due to their high effectiveness. The problem with the use of this process is the leaching of microorganisms from the biofilm and the biological stability of water thus obtained. There is a need to develop quick methods to assess the microbiological quality of this water. Modern techniques for determining the amount of microorganisms, such as flow cytometry and luminometry may be the right tools. The water collected for testing came from the Water Treatment Station located in the Podkarpackie voivodeship. The microbiological tests carried out in the analyzed water samples collected after the filtration process on granular activated carbon. Both traditional culture method and modern techniques used to determine the number of microorganisms (flow cytometry, luminometric ATP assay) demonstrated an increase in the number of microorganisms in the examined waters (in the water after the filtration process and in the water introduced into the water supply network) after the incubation process for 3 and 7 days at 15 and 22°C. [ABSTRACT FROM AUTHOR]

Injection strategies and fuel properties have significant effect on the mixing process of fuel and air in the cylinder, which further affects the combustion and emissions. Three types of gasoline surrogate fuels were tested on a gasoline direct injection (GDI) engine in this paper. The effects of different injection pressures and injection timings on the combustion and emissions of the surrogate fuels were investigated, and the results were compared with those of a commercial gasoline with an octane number of 95. Also, the experiments were conducted at a stoichiometric air-fuel ratio with the engine speed of 2000 rpm and a load of 6 bar. The results show that injection pressure and injection timing have certain effects on the combustion and emissions of the surrogate fuels, which indicates clear differences with the commercial gasoline. In addition, the combustion and emissions of the surrogates are also different due to different compositions. The surrogates have higher in-cylinder pressure and temperature and more advanced combustion phase than commercial gasoline. The surrogates have advantages in NOx emissions and PM emissions under all the testing conditions. Nevertheless, gasoline has much lower CO emissions, THC emissions and most irregular emissions. Generally, low injection pressure and retarded injection timing can be applied to obtain higher thermal efficiency of the surrogate fuels, whereas for gasoline, the injection timing need to be kept at around 300 o CA BTDC. To obtain low CO and THC emissions, gasoline should be applied with low injection pressure and the injection timing should be postponed. On the other hand, for low PM and NOx emissions, the surrogate fuels should be utilized with high injection pressure and the injection timing should be around 300 o CA BTDC. [ABSTRACT FROM AUTHOR]

Solid oxide electrochemical cells (SOCs) can store electrical energy in the form of chemical fuels with high efficiency by electrolysis of CO 2 and H 2 O . However, achieving commercially relevant lifetime is hindered by degradation mechanisms such as carbon deposition, which can even destroy the cell especially during electrolysis where carbon formation is electrochemically driven at the electrode-electrolyte interface. Here we used a three-dimensional multiphysics model to simulate a SOC performing CO 2 electrolysis and determine the operating conditions and locations in the porous nickel-based electrodes where carbon deposition is expected based on local conditions (gas composition, temperature and overpotential) crossing local thermodynamic thresholds. It is found that CO/ CO 2 gas diffusion gradients and cooling from the endothermic electrolysis reaction are important driving forces for carbon deposition to occur locally when it is not expected based on the outlet CO concentration. Furthermore, correlation with a set of experimentally determined threshold operating points indicates that carbon deposition occurs primarily by the Boudouard reaction rather than by direct electrochemical reduction of CO or CO 2 to carbon for the studied cell type. Variation of fuel electrode porosity and thickness shows that these methods of reducing gas diffusion limitations widen the operating window that avoids carbon deposition. [ABSTRACT FROM AUTHOR]

The elevated operating temperatures of solid oxide fuel cells (SOFC) create favorable kinetics for the oxidation of carboncontaining gas mixtures, which may include carbon monoxide and light organic compounds. The presence of carbon-based components in the fuel might result in the formation and deposition of soot on the surface of the anode in a fuel cell. This process depends on and is driven by the prevailing thermodynamic, kinetic and electrochemical conditions. The present study was premised on the following: in addition to the aforementioned parameters providing for the operating conditions, gas velocity also affects the formation of deposits on the anode. The role of fuel gas velocity in the process was studied experimentally using 5 cm x 5 cm anode supported solid oxide fuel cells (AS-SOFC) at 750°C at velocities in the range 0.1 to 0.9 m/s. It was found that carbon deposition was clearly observable approximately 24 hours after the necessary conditions were attained. An intense stage of performance degradation typically lasts for a period of up to 60 hours. An increase in fuel flow velocity leads to an acceleration in the carbon deposition process. The correlation between velocity and cell degradation due to this phenomenon was determined and the corresponding function was proposed. [ABSTRACT FROM AUTHOR]

Ni-based catalysts are very effective and largely used for the steam reforming of heavy hydrocarbons (tars) generated from biomass gasification, even if Ni suffers from deactivation issues mainly due to carbon deposition, sintering and sulphur poisoning. Mayenite (Ca 12 Al 14 O 33 ), as support for Ni, has been previously studied and has shown excellent oxidation properties that increase the resistance of the catalyst to carbon deposits. Nevertheless Ni/Mayenite catalyst still suffers from sulphur poisoning. Ceria (CeO 2 ) is well known to be an effective promoter that can bring several advantages to catalysts, such as enhancing the resistance to carbon deposits and increasing the sulphur tolerance of nickel. Here CeO 2 is added to Ni/Mayenite catalysts to evaluate its promoting features and resistance to deactivation. In this study Ni/Mayenite and Ce/Ni/Mayenite catalysts were synthesized, characterized and tested in the steam reforming of tar model compounds. The catalytic tests were carried out under different operating parameters (temperature, space velocity and nature of tar compounds) and in the presence of sulphur, and the used samples were characterized to identify the reasons of deactivation. [ABSTRACT FROM AUTHOR]

In order to investigate the influence of initial regeneration temperatures on diesel particulate filter (DPF) regeneration, an experimental study of DPF regeneration was implemented using a dielectric barrier discharge (DBD) reactor, aided by exhaust waste heat after engine flameout. DPF trapping characteristics and carbon deposit mass were discussed to facilitate further data analysis and calculation. DPF regeneration was then investigated by comparison analysis of deposit removal mass, backpressure drop, and internal temperature change. The results revealed that a large amount of particulate matter (PM) was deposited in DPF with a high filtration efficiency of about 90 %. The deposit removal rate and percentage drop of the backpressure both maximized at the initial temperature of 100 °C. During DPF regeneration, the sharp rise of internal temperature indicated vigorous PM incineration and high CO2 emission. The results successfully demonstrated DPF regeneration using non-thermal plasma injection during engine flameout, and prominent heat durability was achieved in this method. [ABSTRACT FROM AUTHOR]

One of the important energy saving tools used in solid oxide fuel cell (SOFC) system is the anode off-gas recycling (AGR) via an ejector which allows the recirculation of the unused fuels in the anode exhaust gas including hot steam which is essential for the elimination of the carbon deposition and the initiation of the reactions in the reformer. In an ejector system developed for the SOFCs, the steam to carbon ratio (STCR) and entrainment ratio are the crucial parameters for the determination of the ejector performance. These parameters can be engineered by modifying the geometric dimensions and operation conditions. This study focuses on the determination of the maximum STCR value and entrainment ratio via numerical geometric analyses for a micro combined heat and power (μ-CHP) system based on 4 kW SOFC, utilizing methane. A detailed numerical procedure for designing an ejector is provided and the ejector performance is investigated for different critical dimensions (throat diameter, nozzle exit angle and nozzle position etc.). The results show that the nozzle position and the nozzle exit angle significantly affect STCR and the entrainment ratio. When the nozzle position increases and nozzle exit angle decreases, the entrainment ratio and STCR is found to increase. The entrainment ratio and STCR are determined as around 7.3 and 2.7, respectively for a specific design created in the study. [ABSTRACT FROM AUTHOR]

A rising concern on the depletion of fossil fuel and its growing demand for global energy has promoted research on alternative renewable biofuel. Vegetable oil is marked to be a potential source of energy that can substitute fossil fuels because of its comparable properties to diesel fuel, it is renewable and it is readily available. However, the high viscosity of straight vegetable oil (SVO) limits its application in diesel engines. The high viscosity of SVO can lead to incomplete combustion and carbon deposit in the combustion chamber of an engine. Thus, the blending of SVO with other fuels is seen as an essential and feasible solution in mitigating the issue. In this review, the effects of SVO and its blends on engine performance and emissions are comprehensively studied. Research on the direct use of SVO and several blends such as vegetable oil-diesel blend, vegetable oil-alcohol blend and vegetable oil-alcohol-diesel blend on diesel engine over the last decade are discussed. From these studies, it is found that brake specific fuel consumption (BSFC) for all blends fall between that of SVO and diesel. SVO-diesel blends containing less than 50% SVO have comparable brake thermal efficiency (BTE) to that of diesel fuel. Generally, NO X emitted by SVO, SVO-diesel and SVO-alcohol blends are lower or comparable to that of diesel fuel. Meanwhile, ternary blends of SVO-diesel-alcohol are found to reduce smoke, especially at high load. It is found that CO and unburn HC emissions are vary depending on engine specification, dynamometer operating condition and types of vegetable oil used. Overall, SVO blends are found as potential sources of renewable energy to partially or fully replace diesel fuel. [ABSTRACT FROM AUTHOR]

The paper deals with design of a simple device for the detection of this disorder. In the beginning of the paper the effect of the undesirable detonation combustion in internal combustion engines is described. An engine control unit monitors these detonations using piezoelectric knock sensors. With the control of these sensors the detonations can be objectively measured just outside the car on the test panels. If this component provides small amplitude of the output voltage it could happen that it would have been in the areas of the engine ignition combustion. [ABSTRACT FROM AUTHOR]

Little is known about the effects of using emulsion fuel for extended operation hours. Emulsion fuels comprise of water, low grade diesel fuel (D2) and surfactant in the ratio of 10:89:1 v/v% (E10) and 20:79:1 v/v% (E20). The characteristics of carbon deposits from an engine after a run of 200 h were examined. The carbon deposit analysis performed were macroscopic/microscopic photographs, thermogravimetric analysis (TGA), metal element analysis (MEA) and Fourier transform infrared (FTIR). Increasing water in emulsion fuel decreased particulate matter (PM) and nitrogen oxides (NO x ) altogether. TGA results observed that carbon deposit of E10 engine differed from E20 and D2 engines in terms of its characteristics, which includes darker colour of carbon deposit and the higher volatile content, while the MEA results observed that the elemental metal concentration in the carbon deposit was reduced with increasing water content. The intensity of the spectrum from C H group for the carbon deposit E10 engine was higher compared to carbon deposit D2 and E20 engine respectively due to a complete combustion. Therefore, it was observed that 10% or less water content delivered better fuel consumption, emissions, and carbon deposit. [ABSTRACT FROM AUTHOR]

In this paper, the fractal dimension of carbon deposits from coke oven chamber is defined. The surface of the carbon deposit has been examined using a scanning electron microscopy. The images of surfaces of the carbon deposit are given. The analysis and measurements of fractal clusters images have been presented. The data on the actual density of the deposit and its electrical resistance is given. The sphere-like clusters of the fractal structures are layered bodies. The fractal dimension D of the carbon deposit that is formed in the cells of coke ovens is 2.925. [ABSTRACT FROM AUTHOR]

The pollution of environment and the changes of climate are caused directly by the CO2 emission in combustion process of coal. Chemical looping combustion could easily concentrate CO2 in combustion processes by efficient and energy-saving ways. A new compound oxygen carrier with calcium sulfate and metal oxides is prepared by impregnation method in this paper. The reaction in thermal gravimetric analyzer between the compound oxygen carrier and some gaseous fuels such as CO and some solid fuels such as coal char is investigated. The reaction rate between the compound oxygen carrier impregnated with trace Fe2O3 and NiO and solid fuels is much faster than that between CaSO4 oxygen carrier and solid fuels. Fe2O3 addition improves the reaction performance of oxygen carrier with solid fuels more than NiO. Furthermore, different influencing factors, including pressure, fuel reactor temperature, and oxygen excess number, on the formation of carbon deposits and sulfur evolution are investigated. It can be predicted that the temperatures in the range from 900 to 1050 °C, the pressure form 1 to 5 bar and the excess oxygen number from 0.9 to 1.1 can be regarded as the optimum operation conditions. [ABSTRACT FROM AUTHOR]

While dual fuel low temperature combustion (LTC) has been studied before, a detailed second law analysis of dual fuel LTC is not yet available in the open literature. To address this gap, a previously validated, closed-cycle, multi-zone, simulation of diesel-natural gas dual fuel LTC was used to perform a second law analysis. For the present study, a 2.4-l single-cylinder research engine operating at a nominal load of 6 bar BMEP and 1700 rpm was used. Zone-wise thermodynamic irreversibilities as well as total cumulative entropy generated and lost available work over the closed cycle were quantified. Subsequently, two convenient second-law parameters were defined: (1) the “lost available indicated mean effective pressure” (LAIMEP), which can be interpreted as an engine-size-normalized measure of available work that is lost due to thermodynamic irreversibilities (analogous to the relationship between indicated mean effective pressure and indicated work); (2) fuel conversion irreversibility (FCI), which is defined as the ratio of lost available work to total fuel chemical energy input. Finally, parametric studies were performed to quantify the effects of diesel start of injection, intake manifold temperature, and intake boost pressure on LAIMEP and FCI. The results show that significant entropy generation occurred in the flame zone (52–61 percent) and the burned zone (31–39 percent) while packets account for less than 6 percent of the overall irreversibilities. Parametric studies showed LAIMEPs in the range of 645–768 kPa and FCIs in the range of 32.8–39.2 percent at different engine operating conditions. Although the present study focused on dual fuel LTC, the conceptual definitions of LAIMEP and FCI are generally applicable for comparing the thermodynamic irreversibilities of IC engines of any size and operating on any combustion strategy. [ABSTRACT FROM AUTHOR]

The performance of a Ni-SDC anode-supported cell operating with a dry CH 4 feed stream and the effectiveness of exposing the anode to H 2 as a method of removing carbon deposits are evaluated. This has involved the continuous monitoring of the outlet gas composition during CH 4 operation and H 2 exposure. A degradation rate in the cell voltage (∼1.33 mV h −1 ) is observed during 100 h operation with dry CH 4 . Carbon is detected in the Ni-SDC anode after the stability test but only in the portion of the anode closest to the fuel channel. No carbon is detected at the electrolyte-anode interface, which is the likely reason that the cell performance remains relatively stable. The information obtained from SEM and gas outlet composition analyses can be explained by a process whereby most of the CH 4 that reacts decomposes into H 2 and C in the Ni-SDC anode near the fuel channel. H 2 then makes its way to the anode-electrolyte interface where it is electrochemically oxidized to H 2 O which can also react with any C that may have formed, leaving behind C primarily at the fuel channel. When an aged cell is exposed to H 2 , carbon-containing gases (CO, CH 4 and CO 2 ) are released, indicating that some carbon has been removed from the anode. Examination of the anode after the test shows that some carbon still remains after this treatment. [ABSTRACT FROM AUTHOR]

Ni-based catalysts are prone to be deactivated by carbon deposition. This study aims to investigate the influence mechanism of different types of carbon deposition on the activity of Ni/α-Al 2 O 3 catalyst at various steam-to-carbon (S/C) ratios during steam reforming of toluene for hydrogen production. At a low S/C ratio of 1, the catalytic activity of Ni/α-Al 2 O 3 was inhibited due to the covering and blocking of Ni active sites by the formation of amorphous carbon on the Ni surface. While at a high S/C ratio of 3, more than 80 wt% of carbon deposition was found to be self-growth carbon nanotubes (CNTs) with an average diameter of around 15 nm. The activity of Ni/α-Al 2 O 3 in steam reforming of toluene was unusually promoted, which can be attributed to the tip-growth mechanism of CNTs, whereby the Ni particles migrated to the tip or the surface of CNTs, resulting in the improved active site dispersion. [ABSTRACT FROM AUTHOR]

Water table depth (WTD) effects on net ecosystem CO2 exchange of boreal peatlands are largely mediated by hydrological effects on peat biogeochemistry, and eco-physiology of peatland vegetation. Lack of representation of these effects in carbon models currently limits our predictive capacity for changes in boreal peatland carbon deposits under future drier and warmer climates. We therefore tested whether the effects of WTD variation on net ecosystem CO2 exchange of a Western Canadian boreal fen peatland could be modelled through a process-level coupling of a prognostic WTD dynamic, which arises from equilibrium between vertical and lateral water fluxes, with oxygen transport, which controls energy yields from microbial and root oxidation-reduction reactions, and vascular and non-vascular plant water relations in an ecosystem model ecosys. Ecosys successfully simulated a May-October WTD drawdown by ~ 0.25 m measured in the fen from 2004 to 2008, which was attributed to reduced precipitation relative to evapotranspiration, and reduced lateral recharge relative to discharge. This WTD drawdown hastened oxygen transport to microbial and root surfaces, enabling greater microbial and root energy yields, and peat and litter decomposition, which raised modelled ecosystem respiration (Re) by ~ 0.26 Āmol CO2 m-2 s-1 per 0.1 m of WTD drawdown. It also augmented nutrient mineralization, and hence root nutrient availability and uptake, which resulted in improved leaf nutrient (nitrogen) status that facilitated carboxylation, and raised modelled vascular gross primary productivity (GPP). This increase in modelled vascular GPP exceeded declines in modelled non-vascular (moss) GPP due to greater shading from increased vascular plant growth, and moss drying from near surface peat desiccation, thereby causing a net increase in modelled growing season GPP by ~ 0.39 Āmol CO2 m-2 s-1 per 0.1 m of WTD drawdown. Similar increases in GPP and Re left no significant WTD effects on modelled variations of net ecosystem productivity (NEP). These modelled trends were corroborated against eddy covariance hourly net CO2 fluxes (modelled vs. measured: R2 ~ 0.8, slopes ~ 1 ± 0.1, intercepts ~ 0.05 Āmol m-2 s-1), and against other automated chamber, biometric, and laboratory measurements. Modelled drainage as an analog for climate change showed that this boreal peatland would switch from a large carbon sink (NEP ~ 160 g C m-2 yr-1) to carbon neutrality (NEP ~ 10 g C m-2 yr-1) should water table deepened by a further ~ 0.5 m. Therefore, representing interactions among hydrology, biogeochemistry and plant physiological ecology on carbon, water, and nutrient cycling in global carbon models would improve our predictive capacity for changes in boreal peatland carbon sequestration under changing climates. [ABSTRACT FROM AUTHOR]

The use of dielectric property assessment to gauge the catalytic activity and rate of deactivation of heterogeneous catalysts is reported. Four supported catalysts containing a combination of Fe and Ni active sites and γ-Al2O3, ZSM-5, MCM-41, and SBA-15 supports were synthesized, characterized, and utilized to catalyze a Fischer-Tropsch process over a temperature range of 250-400 °C that was specifically directed toward the production of lower olefins. While the highest conversion was obtained from ZSM-5 and MCM-41 supports containing Fe and Ni as active sites at 350 °C, all these catalysts were observed to be deactivated by the formation of carbon on their surface. The dielectric properties of the fresh, used catalysts and supports were evaluated and correlated with their catalytic activity and structural/textural properties. It was clearly shown that the dielectric property measurement could demonstrate both the presence and magnitude of carbon deposits on the catalyst via the differences in the values of fresh and used catalysts. Furthermore, the ability to differentiate between the levels of the carbon deposition observed was shown to be independent of the morphology exhibited by the carbon deposit demonstrating that this is a method that can be generally applied. [ABSTRACT FROM AUTHOR]

This study has completed the preliminary test of the “automotive hydrogen gas release controller with low pressure hydrogen storage module” in the carbon removal of cars engine, this product has integrated (1) a low pressure hydrogen storage cylinder (metal hydride) and (2) a solenoid valve controller with flow meter. Under normal temperature and pressure settings, this system is able to transfer hydrogen gas to the vehicle's intake air system and mixing with the air, entering the engine chamber. The solenoid valve controller and flow meter can control the optimized hydrogen gas output flow rate, activating the carbon deposit removal. The results of this study show that in the example for a 1,600 cc vehicle, 1690 USD may be saved for gasoline in a year with reducing 164.8 ton of CO 2 emission (The enhancing of fuel utilization 11.6%). For a 2,000 cc vehicle, 3070 USD may be saved for gasoline in a year with reducing 291 ton of CO 2 emission (The enhancing of fuel utilization 20.6%). A set of low pressure hydrogen storage system has been developed in this research, it is safe and convenient for consumers, the Solenoid Valve Controller and Flow meter allows for optimized use of hydrogen gas, reducing the waste of excess hydrogen gas. [ABSTRACT FROM AUTHOR]

• The N-MP-P catalyst exhibited the best stability performance and resistance to carbon deposition than that of the N-M-C catalyst. • The decreased Si-OH groups on the support surface would promote to prevent the agglomeration of Ni species and enhance the dispersion of Ni species. • The catalyst precursor was modified by RF plasma, obtaining smaller particle sizes and highly dispersed of Ni species and more surface adsorbed oxygen. The radio frequency plasma was used to decorate the MCM-41 support or to treat the catalyst precursor. The structures and CO 2 CH 4 reforming performances of nickel-based catalysts prepared by different plasma treated modes were compared. The catalysts were characterized by XRD, FT-IR, H 2 -TPR, XPS, TEM, TG and contact angle. Comparing with the calcined catalyst supported on common MCM-41 (N-M-C), the plasma treated catalyst supported on plasma decorated MCM-41(N-MP-P) showed highest activity and best stability because of less Si-OH groups on support, smaller nickel particle size and more homogeneously dispersion as well as stronger interaction between nickel-MCM-41. The average CH 4 and CO 2 conversions were increased by 24.0% and 19.3%, respectively. After 30 h reaction, there was a little loss of the conversions, and the carbon deposition was decreased from 35.8% on N-M-C to 0.8% on N-MP-P; additionally, the Ni particle size was reduced from 20.9 to 8.5 nm, which proved that the coke resistance was apparently promoted. Comparing with the effect of plasma decorating the support, that of plasma treating the catalyst precursor played a more important role in the structure and catalytic performance of the Ni-based catalyst. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study it is theoretically analyzed how flue gas recirculation at the hydrogen electrode of solid oxide cells (SOC) systems effects fuel utilization and carbon formation. Interdepence between cell fuel utilization, system fuel utilization and gas recirculation is investigated numerically. Tendency towards carbon deposits is evaluated via thermodynamic equilibrium calculations. It is quantified which gas recirculation rates are necessary to achieve high values of system fuel utilization even if the cell fuel utilization is kept at a moderate level. Furthermore, tendency towards carbon deposition strongly depends on temperature, pressure and feed gas composition and can be reduced by adequate recirculation rates. The presented results can be used for the configuration of gas recirculation in SOC systems. [ABSTRACT FROM AUTHOR]

Understanding the formation of carbon deposits in zeolites is vital to developing new, superior materials for various applications, including oil and gas conversion processes. Herein, atom probe tomography (APT) has been used to spatially resolve the 3D compositional changes at the sub-nm length scale in a single zeolite ZSM-5 crystal, which has been partially deactivated by the methanol-to-hydrocarbons reaction using 13C-labeled methanol. The results reveal the formation of coke in agglomerates that span length scales from tens of nanometers to atomic clusters with a median size of 30-60 13C atoms. These clusters correlate with local increases in Brønsted acid site density, demonstrating that the formation of the first deactivating coke precursor molecules occurs in nanoscopic regions enriched in aluminum. This nanoscale correlation underscores the importance of carefully engineering materials to suppress detrimental coke formation. [ABSTRACT FROM AUTHOR]

The properties, performance, and exhaust emissions of a four-cylinder indirect injection diesel engine fueled by FAME from waste coconut oil was evaluated in this study. Polymerization and carbon deposits on fuel-injector nozzles were also monitored. Ordinary diesel (OD) oil was used as a benchmark for comparison purposes. Tests included measuring high heating value, kinematic viscosity, specific density, cetane index, pour point, flash point, and Conradson carbon residue. Results showed that, the high calorific value decreased with increased coconut oil in coconut-oil blends. On average, the calorific value of all coconut-oil blends were about 6% lower than that of OD fuel. Density increased with increased coconut oil in coconut-oil blends because of the higher amount of carbon atoms in coconut-oil molecules. As a result, viscosity also increased with increased coconut oil in blends. Other properties of blended fuels varied according to their physicochemical properties. Results also showed that the brake power output of engine increased by about 5% when fueled by 30% coconut-oil-blended fuel. The average specific fuel consumption of coconut-oil-blended fuels increased by 7–10% compared with OD oil. The exhaust emissions of blended fuel were found to be much cleaner, containing less CO, HC, NO x, and smoke and benzene concentration. The coconut-oil-blended fuel also produced low particulate emission and carbon deposit on injector nozzles. For each coconut-oil-blended fuel, the engine did not have any starting difficulty and combustion noise at >25 °C. The coconut-oil-based fuel also did not pose a severe environmental threat because of its low sulfur content. [ABSTRACT FROM AUTHOR]

In this contribution we present the results of a parallel high-throughput screening (HTS), which was carried out to identify new catalysts for the total oxidation of methane, a chemical compound that shows a significantly higher global warming potential compared to carbon dioxide. An interesting application for these materials is the abatement of unburned methane in exhaust gases from biogas fueled lean burn engines. After the synthesis of a high variety of different materials by a sol-gel procedure and their evaluation by infrared thermography under simplified reaction conditions, the activity of the most promising candidates was validated under a complex exhaust gas composition in a conventional plug flow reactor. The aging behavior of the best catalysts from the HTS was studied in a tenfold parallel reactor setup. Only a small number of the studied materials exhibited an interesting long term stability during the aging procedure. With this approach a high number of potential materials can be rapidly reduced to only a few catalysts which are promising for a possible industrial application. [ABSTRACT FROM AUTHOR]

A biomass oil/diesel blend was prepared using an emulsion method and combusted in a diesel engine. An injector was then removed and the morphology, composition, and structure of the carbonaceous deposits on the pintle-type nozzle were characterized using a combination of HRTEM, SEM/EDAX, Raman and XRD. Results showed that the carbon deposition of the emulsified fuel with high crystallinity was greater than that of diesel. The agglomerated particulate diameters of the deposited carbon from diesel and emulsified fuel were approximately 10–30 μm and 50 μm, respectively. The carbon deposition mechanism from the emulsified fuel was attributed to the high oxygen content of the groups leading to increased polymerization and subsequent condensation on the nozzle surfaces that was then carbonised. [ABSTRACT FROM AUTHOR]

Inland navigation is of increasing economic and ecological interest, however its contribution to environmental quality is hardly known. We hypothesized that i) inland navigation emits considerable amounts of soot-Black Carbon (BC) as a product of incomplete combustion of diesel fuel, which is then deposited on soils along river valleys, that ii) improvement of fuel quality by sulfur reduction in 2011 decreased BC inputs to soil, and that iii) this provides a tracer for the spatial impact of inland navigation emissions. The spatial and temporal patterns of soil BC deposits from inland navigation were investigated yearly (2010–2013) working within transects perpendicular to the rivers Rhine, Moselle and Ahr, Germany (the Ahr Valley is free of shipping and served as a reference). In rural areas at inland waterways navigation likely represented the dominant BC emitter. Topsoils (0–10 cm depth) were sampled in vineyards. Their BC content and composition was determined via oxidation of bulk soil organic matter to benzene polycarboxylic acids (BPCAs). The highly trafficked Rhine Valley yielded only little more BC (64.7 ± 12 g BC kg −1 soil organic carbon (SOC) compared to 51.7 ± 9 at the Moselle, and 53.6 ± 6 at the reference Ahr Valley). At both inland waterways soil BC increased towards the river, following the simulated dispersal of ship-derived BC using a Lagrangian model. In the course of ship fuel regulation, soil BC deposits at the Rhine and Moselle waterways decreased significantly from 70.2 ± 3.2 to 47.9 ± 1.1 and 57.6 ± 1.3 to 41.7 ± 0.9 g BC kg −1 SOC within 3 years. Even more pronounced was the change in BC composition, i.e., the ratio of pentacarboxylated to mellitic acid increased from 0.75 to 1.3 (Rhine) and 1 to 1.4 (Moselle) during this time span. From this we calculated that ∼30% less BC was deposited by inland navigation likely due to reduced BC emissions after sulfur regulation in ship diesel. [ABSTRACT FROM AUTHOR]

The emissions from the Compression ignition (CI) engines introduce toxicity to the atmosphere. The undesirable carbon deposits from these engines are realized in the nearby static or dynamic systems such as vehicles, inhabitants, etc. The objective of this research work is to improve the performance and emission characteristics of a diesel engine in the modified re-entrant combustion chamber using a diesel and Jatropha methyl ester blend (J20) at three different injection pressures. From the literature, it is revealed that the shape of the combustion chamber and the fuel injection pressure have an impact on the performance and emission parameters of the CI engine. In this work, a re-entrant combustion chamber with three different fuel injection pressures (200, 220 and 240 bars) has been used in the place of the conventional hemispherical combustion chamber for diesel and J20. From the experimental results, it is found that the re-entrant chamber improves the brake thermal efficiency of diesel and J20 in all the tested conditions. It is also found that the 20% blend of Jatropha methyl ester showed 4% improvement in the brake thermal efficiency in the re-entrant chamber at the maximum injection pressure. Environmental safety directly relates to the reduction in the undesirable effects on both living and non-living things. Currently environmental pollution is of major concern. Even with the stringent emission norms new methods are required to reduce the harmful effects from automobiles. The toxicity of carbon monoxide (CO) is well known. In the re-entrant combustion chamber, the amount of CO emission is reduced by 26% when compared with the conventional fuel operation of the engine. Moreover, the amount of smoke is reduced by 24% and hydrocarbons (HC) emission by 24%. Thus, the modified re-entrant combustion chamber reduces harmful pollutants such as unburned HC and CO as well as toxic smoke emissions. [ABSTRACT FROM AUTHOR]

When Jet fuels are exposed to high temperatures and pressures, carbon deposits are formed, and cause a number of performance issues in aircraft systems. One method for reducing the amount of carbon deposits is by the addition of dispersants to jet fuels. In this study, we investigated the effectiveness of polyisobutenyl succinimide (PIBSI) type dispersants in reducing the carbon deposits formed by thermal oxidative decomposition of Jet A-1. PIBSI type dispersants have amphiphilic structures consisting of a polar head and a nonpolar tail. The polar head adsorbs onto the carbon deposit precursors and the nonpolar tail prevents the aggregation of the precursors. An important factor governing the extent of adsorption is the polarity of the head, which is dependent on the polar surface area and the orbital electronegativity. Diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), and pentaethylenehexamine (PEHA) were used as the head groups of alkyleneamines in this study. It was found that the dispersants that had head groups with a large polar surface area and orbital electronegativity strongly adsorbed onto the carbon deposit precursors and exhibited high efficiency with carbon deposit reduction. Based on these results, we propose dispersants containing amino ether groups in the head, as they showed improved carbon deposit reduction efficiencies compared to typical dispersants containing alkyleneamines in the head group. [ABSTRACT FROM AUTHOR]

Anodes for Solid Oxide Fuel Cell that is capable of directly using hydrocarbon without external reforming have been of great interest recently. In this paper, a three-layer structure anode running on methane is fabricated by tape casting and screen printing method. The slurry of catalyst layer Cu-LSCM-CeO2 (with weight ratios of 1.5:7.0:1.5, 2.0:7.0:1.0, 2.15:7.0:0.85 and 2.25:7.0:0.75, weight ratios of Cu/CeO2 is 1:1, 2:1, 2.5:1 and 3:1, respectively) is screen-printed on LSCM-YSZ support layer and Ni-ScSZ active layer. Thus, LSCM-YSZ/Ni-ScSZ anodes with Cu-LSCM-CeO2 catalyst layer (denoted as LSCM-YSZ1010, LSCM-YSZ2010, LSCM-YSZ2510 and LSCM-YSZ3010, respectively) are obtained. Single cells with three-layer structure anode are also fabricated and measured, of which the maximum power density reaches 491 and 670 mW cm−2 for the cell with LSCM-YSZ2510 anode running on methane at 750 °C and 800 °C, respectively. No significant degradation in performance has been observed after 240h of cell testing when LSCM-YSZ2510 anode is exposed to methane at 750 °C. Very little carbon deposition is detected on the anode, suggesting that carbon deposition is limited during cell operation. Consequently, Cu-LSCM-CeO2 catalyst layer on the surface of LSCM-YSZ support layer makes it possible to have good stability for long-term operation in methane due to very little carbon deposition. [ABSTRACT FROM AUTHOR]

The three-dimensional structures of carbon deposits on piston surfaces in a large-scale two-stroke marine diesel engine have been nondestructively investigated using synchrotron X-ray microtomography. The results indicate that the piston carbon deposit (PCD) has a flat bottom surface where many irregular structures accumulate. Based on the microtomography, cross sections of the carbon deposit sample can be obtained in the direction perpendicular to the piston surface. A uniform deposition is found on the bottom surface of piston, where many tiny pores appear, which implies that a liquid film first forms on the piston surface and subsequent nucleation boiling occurs due to the high surface temperature. A significant decrease in the PCD density is observed when the PCD thickness is below a threshold of approximately 150 μm. However, the PCD density remains almost unchanged from 150 to 1800 μm. This result suggests that there should be different dominant formation mechanisms at these two stages. The local morphology, especially the approximately circular structure and the smooth boundary on the PCD surface, indicates that condensation should be the major factor controlling the formation of the PCD surface. However, the internal pores and minimal swelling on the surface could result from other mechanisms. [ABSTRACT FROM AUTHOR]

A multi-phase mixed proton-oxide ion-electron conducting composite is employed as a new anode material for a coking-resistant solid oxide fuel cell (SOFC) based on oxide ion conducting electrolyte, operated in methane and ethanol. The formation of BaO/Ni interfaces can effectively readily adsorb water and facilitate water-mediated carbon removal. The fast oxygen ions flux and formed steam at anode side are also found to be favorable for hydrocarbon reformation to promote the cell performance and long term stability. At 700 °C, maximum power densities of 580 and 368 mW cm −2 are achieved in methane and ethanol, respectively. The resistance against carbon deposition is significantly improved, showing stable voltage in 120 h durability test. [ABSTRACT FROM AUTHOR]

Hydrogen and methane are widely used as fuel for solid oxide fuel cells (SOFCs) and have been extensively researched. The usage of high-temperature SOFCs for mobile applications such as auxiliary power units will be a seminal field of application. The biggest advantage of currently used liquid fuels for combustion engines is their high volumetric energy density. Diesel can be used as fuel for SOFCs when it is reformed. In this study a CFD simulation model of a planar industrial-sized 100 × 100  mm 2 SOFC fed with diesel reformat was examined. Its size and geometry as well as the fuel are suitable for future applications and therefore investigation is of special interest. The electrochemical and thermal performance was investigated and validated with in-house experimentally determined data. In order to identify the influence of radiative heat transfer, the Surface-to-Surface and the Discrete Ordinates Model were used for radiation modeling. A very high degree of consensus of simulated and experimentally designated data was reached for the entire temperature range and different fuel compositions. The created CFD model will be used as a base model for future simulations of carbon deposition on the cell's anode. [ABSTRACT FROM AUTHOR]

Burning off is the main method of carbon deposit removal from coke oven chambers. The heterogeneous reaction must be considered when the air blowing eliminates wall polycarbonate in the coke oven. In the three-dimensional problem of the burning off in the coke oven, the turbulent flow is induced by the interaction of the forced convection form the air inlet and natural convection from the high temperatures on the wall. This paper intends to show that the models can be generated by the solution of equations of conservation of mass, energy and spices in the boundary layer while lumping at the surface all the intraparticle effects. In order to understand the Sorect effect, there were three cases comparison. From the results, the Sorect effect is not clear, and P1 model has highly nonphysical behavior together with numerical instabilities inherent to the model. [ABSTRACT FROM AUTHOR]

For large-scale and reliable implementation of biodiesel in transportation engines, its effects on engine wear and engine durability upon prolonged usage needs to be experimentally investigated. Therefore effects of 20% Karanja biodiesel blend (KOME20) on engine wear and durability was studied vis-à-vis mineral diesel in 250 h long endurance test on a direct injection compression ignition (DICI) engine. Visual inspection of engine components for deposits indicted higher carbon deposits on piston top, cylinder head and injector tip for biodiesel fuelled engine. Relatively lower wear of valves, pistons, piston rings, liners and small end bearings of the connecting rods was observed for biodiesel fuelled engine. Wear of big end bearing of the connecting rods, main bearings and crank pins was found to be higher for biodiesel fuelled engine. Surface texture of cylinder liners remained in acceptable condition after the endurance test for mineral diesel as well as Karanja biodiesel blend. Despite higher carbon deposits and higher wear of some vital engine components, no operational problems were observed during the long-term endurance test for the biodiesel fueled engine. [ABSTRACT FROM AUTHOR]

Prospects for mitigating climate change require decarbonisation of the energy sector over relatively short time periods, coupled with significant changes to the way we consume energy. This is particularly true in the transport sector given the current levels of transport-related greenhouse gas emissions, the heavy dependence on fossil fuels, and the uncertainty surrounding transition pathways to ultra-low carbon vehicles. There are policy responses aiming to reduce carbon emissions by changing travel behaviour, but prominent approaches share a common theme of seeking to change behaviour by focusing on the individual and their choices. These are the object of critics who maintain that effective change requires collective action at the social, economic and cultural levels. This paper questions whether decision-makers are relying on these choice-based approaches to change travel behaviour and, if so, how effective they expect them to be. We address this through analysis of over 50 interviews with policy stakeholders in England and Scotland. We find dominant policy approaches do focus on individual choices, but significantly it is not because decision-makers have faith in their effectiveness. These approaches persist in policy on carbon reduction for two reasons. One is appeal to a politically powerful, but incoherent, discourse of individualism. The second is that decision-makers do not want significant behavioural change. There is an imperative of economic growth and a firm belief that a strong economy is linked to higher traffic levels, and that to reduce the demand for travel is to risk economic damage. We argue that these beliefs about the relation between travel demand and prosperity are narrowly defined and contestable for empirical and normative reasons. If there is to be a significant change in the approach to intervening in travel demand there is an urgency to engage in the politics of behaviour change - a meta-level behaviour change challenge. [ABSTRACT FROM AUTHOR]

The article explores the challenges on the shortage of petroleum production among foreign energy industries. Topics discussed include the federal government's efforts to developed infinite carbon programs, the trends in discovering techniques in producing alternative fuels and the business opportunities of hydrocarbon producer countries. Also mentioned is the efforts of the U.S. Energy Information Administration to monitor the supply of petroleum and shale gas products in the country.

Highlights: [•] A novel anodic alumina monolith was applied for DME hydrolysis. [•] The product distributions on different acidic catalysts were studied. [•] The novel monolith has an excellent resistance to carbon deposition. [ABSTRACT FROM AUTHOR]

Abstract: The effect of ignition location on the effectiveness of combustion deposit removal from the reverse side of an optical window in a laser ignition system for use in gas turbines is presented. Such deposits consist of carbon and other by-products which accumulate on the walls of the chamber as a result of incomplete combustion. In laser based ignition systems this accumulation of combustion deposits has the potential to reduce the transmissive properties of the output window required for transmission of the laser radiation into the combustion chamber, adversely affecting the likelihood of successful ignition. In this work, a full empirical study into the in-process removal of combustion deposits from the reverse side of the optical window in a laser ignition system using a Q-switched Nd:YAG laser is presented, with an emphasis on the effect of ignition location on the effectiveness of combustion deposit removal. In addition, the mechanism of deposit removal is discussed. [Copyright &y& Elsevier]