Chenchen Geng, Yingjuan Shao, Wenqi Zhong, Xuejiao Liu
Closed supercritical carbon dioxide (S-CO2) Brayton cycle is a promising alternative to steam Rankine cycle due to higher cycle efficiency at equivalent turbine inlet conditions, which has been explored to apply to nuclear, solar power, waste heat recovery, and coal-fired power plant. This study establishes 300MW S-CO2 power system based on modified recompression Brayton cycle integrated with coal-fired circulating fluidized bed (CFB) boiler. The influences of two stages split flow on system performance have been investigated in detail. In addition, thermodynamic analysis of critical operating parameters has been carried out, including terminal temperature difference, turbine inlet pressure/temperature, reheat stages, and parameters as well as compressor inlet pressure/temperature. The results show that rational distribution of split ratio to the recompressor (SR1) achieves maximal cycle efficiency where heat capacities of both sides in the low temperature recuperator (LTR) realize an excellent matching. The optimal SR1 decreases in the approximately linear proportion to high pressure turbine (HPT) inlet pressure due to gradually narrowing specific heat differences in the LTR. Secondary split ratio to the economizer of CFB boiler (SR2) can recover moderate flue gas heat caused by narrow temperature range and improve boiler efficiency. Smaller terminal temperature difference corresponds to higher efficiency and brings about larger cost and pressure drops of the recuperators, which probably decrease efficiency conversely. Single reheat improves cycle efficiency by 1.5% under the condition of 600°C/600°C/25Mpa while efficiency improvement for double reheat is less obvious compared to steam Rankine cycle largely due to much lower pressure ratio. Reheat pressure and main compressor (MC) inlet pressure have corresponding optimal values. HPT and low pressure turbine (LPT) inlet temperature both have positive influences on system performance.
{"title":"Thermodynamic Analysis of Supercritical CO2 Power Cycle with Fluidized Bed Coal Combustion","authors":"Chenchen Geng, Yingjuan Shao, Wenqi Zhong, Xuejiao Liu","doi":"10.1155/2018/6963292","DOIUrl":"https://doi.org/10.1155/2018/6963292","url":null,"abstract":"Closed supercritical carbon dioxide (S-CO2) Brayton cycle is a promising alternative to steam Rankine cycle due to higher cycle efficiency at equivalent turbine inlet conditions, which has been explored to apply to nuclear, solar power, waste heat recovery, and coal-fired power plant. This study establishes 300MW S-CO2 power system based on modified recompression Brayton cycle integrated with coal-fired circulating fluidized bed (CFB) boiler. The influences of two stages split flow on system performance have been investigated in detail. In addition, thermodynamic analysis of critical operating parameters has been carried out, including terminal temperature difference, turbine inlet pressure/temperature, reheat stages, and parameters as well as compressor inlet pressure/temperature. The results show that rational distribution of split ratio to the recompressor (SR1) achieves maximal cycle efficiency where heat capacities of both sides in the low temperature recuperator (LTR) realize an excellent matching. The optimal SR1 decreases in the approximately linear proportion to high pressure turbine (HPT) inlet pressure due to gradually narrowing specific heat differences in the LTR. Secondary split ratio to the economizer of CFB boiler (SR2) can recover moderate flue gas heat caused by narrow temperature range and improve boiler efficiency. Smaller terminal temperature difference corresponds to higher efficiency and brings about larger cost and pressure drops of the recuperators, which probably decrease efficiency conversely. Single reheat improves cycle efficiency by 1.5% under the condition of 600°C/600°C/25Mpa while efficiency improvement for double reheat is less obvious compared to steam Rankine cycle largely due to much lower pressure ratio. Reheat pressure and main compressor (MC) inlet pressure have corresponding optimal values. HPT and low pressure turbine (LPT) inlet temperature both have positive influences on system performance.","PeriodicalId":44364,"journal":{"name":"Journal of Combustion","volume":"43 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2018-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89794167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Bade, N. Clark, Matthew C. Robinson, P. Famouri
An Oscillating Linear Engine Alternator (OLEA) has the potential to overcome the thermal, mechanical, and combustion inadequacies encountered by the conventional slider-crank engines. The linear engines convert the reciprocating piston motion into electricity, thereby eliminating needless crankshaft linkages and rotational motion. As the dead center positions are not explicitly identified unlike crankshaft engines, the linear engine exhibits different stroke and compression ratio every cycle and should manage the unfavorable events like misfire, rapid load changes, and overfueling without the energy storage of a flywheel. Further, the apparatus control and management strategy is difficult for OLEA when compared to conventional engines and depends on the combustion event influencing the translator dynamics. In this research paper, the MATLAB®/Simulink numerical model of a single cylinder, mechanical spring assisted, 2-stroke natural gas fueled, spark-ignited OLEA was investigated to enhance the perception of the coupled system. The effect of combustion and heat transfer characteristics on translator dynamics and performance of OLEA were analyzed by using Wiebe form factors, combustion duration, and heat transfer correlations. Variation in the Wiebe form factors revealed interesting insights into the translator dynamics and in-cylinder thermodynamics of a coupled system. High translator velocity, acceleration, and higher heat transfer rate were favored by low combustion duration.
{"title":"Parametric Investigation of Combustion and Heat Transfer Characteristics of Oscillating Linear Engine Alternator","authors":"M. Bade, N. Clark, Matthew C. Robinson, P. Famouri","doi":"10.1155/2018/2907572","DOIUrl":"https://doi.org/10.1155/2018/2907572","url":null,"abstract":"An Oscillating Linear Engine Alternator (OLEA) has the potential to overcome the thermal, mechanical, and combustion inadequacies encountered by the conventional slider-crank engines. The linear engines convert the reciprocating piston motion into electricity, thereby eliminating needless crankshaft linkages and rotational motion. As the dead center positions are not explicitly identified unlike crankshaft engines, the linear engine exhibits different stroke and compression ratio every cycle and should manage the unfavorable events like misfire, rapid load changes, and overfueling without the energy storage of a flywheel. Further, the apparatus control and management strategy is difficult for OLEA when compared to conventional engines and depends on the combustion event influencing the translator dynamics. In this research paper, the MATLAB®/Simulink numerical model of a single cylinder, mechanical spring assisted, 2-stroke natural gas fueled, spark-ignited OLEA was investigated to enhance the perception of the coupled system. The effect of combustion and heat transfer characteristics on translator dynamics and performance of OLEA were analyzed by using Wiebe form factors, combustion duration, and heat transfer correlations. Variation in the Wiebe form factors revealed interesting insights into the translator dynamics and in-cylinder thermodynamics of a coupled system. High translator velocity, acceleration, and higher heat transfer rate were favored by low combustion duration.","PeriodicalId":44364,"journal":{"name":"Journal of Combustion","volume":"8 1","pages":"1-16"},"PeriodicalIF":0.7,"publicationDate":"2018-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80929101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present research work is comprised of three main parts. The first part is about the enrichment of lignite coal by the utilization of dense medium separation called float and sink method. The second part deals with the investigation of the thermal behaviour for the coals enriched while the last part is concerned with the kinetic analysis of the coal combustion. The float and sink method is the mostly used technique for low-rank coal beneficiation in coal preparation plants of Turkey. In order to realize this process, the coal samples were, at first, fractioned to five different sizes which were -32+25 mm, -25+16 mm, -16+8 mm, -8+4.75 mm, and -4.75+2 mm. Each fraction was, then, processed in the dense mediums with the specific gravities of 1.20, 1.30, 1.40, 1.50, and 1.60 g/cm3, respectively. The thermal behaviour of the floated materials from the float and sink process was investigated in detail with the thermogravimetric analysis (TG) and the differential thermogravimetric analysis (DTG). The ignition and peak temperatures for the samples were also ascertained and correlated with the float and sink test results. In the final part of the study, the kinetic analysis of the coal samples was carried out by the Coats–Redfern method and the activation energies of the enriched coals were determined. The activation energies of the raw and the enriched coals were assessed and compared. The calculated activation energy values for the combustion reactions of the coal samples ranged were found to be between 15.17 kJ/mol and 97.45 kJ/mol. The strong correlation was obtained between the float and sink test results especially with the ash content of the coal samples and the combustible characteristic of the floated materials such as ignition temperatures, peak temperatures, and activation energies. The combustion characteristics of the coal samples were resultantly ascertained to be very dependent on the coal structure.
{"title":"Investigation of the Thermal Improvement and the Kinetic Analysis of the Enriched Coal","authors":"S. Duzyol, C. Sensogut","doi":"10.1155/2018/1761023","DOIUrl":"https://doi.org/10.1155/2018/1761023","url":null,"abstract":"The present research work is comprised of three main parts. The first part is about the enrichment of lignite coal by the utilization of dense medium separation called float and sink method. The second part deals with the investigation of the thermal behaviour for the coals enriched while the last part is concerned with the kinetic analysis of the coal combustion. The float and sink method is the mostly used technique for low-rank coal beneficiation in coal preparation plants of Turkey. In order to realize this process, the coal samples were, at first, fractioned to five different sizes which were -32+25 mm, -25+16 mm, -16+8 mm, -8+4.75 mm, and -4.75+2 mm. Each fraction was, then, processed in the dense mediums with the specific gravities of 1.20, 1.30, 1.40, 1.50, and 1.60 g/cm3, respectively. The thermal behaviour of the floated materials from the float and sink process was investigated in detail with the thermogravimetric analysis (TG) and the differential thermogravimetric analysis (DTG). The ignition and peak temperatures for the samples were also ascertained and correlated with the float and sink test results. In the final part of the study, the kinetic analysis of the coal samples was carried out by the Coats–Redfern method and the activation energies of the enriched coals were determined. The activation energies of the raw and the enriched coals were assessed and compared. The calculated activation energy values for the combustion reactions of the coal samples ranged were found to be between 15.17 kJ/mol and 97.45 kJ/mol. The strong correlation was obtained between the float and sink test results especially with the ash content of the coal samples and the combustible characteristic of the floated materials such as ignition temperatures, peak temperatures, and activation energies. The combustion characteristics of the coal samples were resultantly ascertained to be very dependent on the coal structure.","PeriodicalId":44364,"journal":{"name":"Journal of Combustion","volume":"22 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2018-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87193152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The purpose of this paper is to conduct an experimental research on the impact of mixing ratio of biodiesel from waste cooking oil and an innovative diesel fuel (in which a renewable component is contained) on the emissions of an up-to-date light and compact small engine that has a leading role in city cars and urban vehicles. Two blends’ mixing ratios (20% and 40% by volume) were tested and the results were compared to those obtained when the engine was operated with low sulfur diesel (ULSD) and ULSD blended with 15% by volume of renewable diesel. The results indicate that diesel+ enhances CO and HC emissions in the exhaust as regards ULSD. Blending diesel+ with WCO causes a further reduction for most of the engine operative field. Concerning particulate emission, accumulation mode dominates for all fuels. Diesel+ is always characterized by lower mean diameters as regards ULSD. The addition of WCO further reduces the court mean diameter. Particle number concentration obtained by fuelling the engine with B40 is the lowest as regards all the other tested fuels. Concerning , a moderate increase of the emission was observed when fuelling the engine with diesel+, net or in blends.
{"title":"Emission Performance of a Diesel Engine Fuelled with Petrol Diesel, Green Diesel, and Waste Cooking Oil Blends","authors":"O. Chiavola, Erasmo Recco","doi":"10.1155/2018/4819175","DOIUrl":"https://doi.org/10.1155/2018/4819175","url":null,"abstract":"The purpose of this paper is to conduct an experimental research on the impact of mixing ratio of biodiesel from waste cooking oil and an innovative diesel fuel (in which a renewable component is contained) on the emissions of an up-to-date light and compact small engine that has a leading role in city cars and urban vehicles. Two blends’ mixing ratios (20% and 40% by volume) were tested and the results were compared to those obtained when the engine was operated with low sulfur diesel (ULSD) and ULSD blended with 15% by volume of renewable diesel. The results indicate that diesel+ enhances CO and HC emissions in the exhaust as regards ULSD. Blending diesel+ with WCO causes a further reduction for most of the engine operative field. Concerning particulate emission, accumulation mode dominates for all fuels. Diesel+ is always characterized by lower mean diameters as regards ULSD. The addition of WCO further reduces the court mean diameter. Particle number concentration obtained by fuelling the engine with B40 is the lowest as regards all the other tested fuels. Concerning , a moderate increase of the emission was observed when fuelling the engine with diesel+, net or in blends.","PeriodicalId":44364,"journal":{"name":"Journal of Combustion","volume":"27 1","pages":"1-9"},"PeriodicalIF":0.7,"publicationDate":"2018-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79305050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Initial conditions of the working fluid (air-fuel mixture) within an engine cylinder, namely, mixture composition and temperature, greatly affect the combustion characteristics and emissions of an engine. In particular, the percentage of residual gas fraction (RGF) in the engine cylinder can significantly alter the temperature and composition of the working fluid as compared with the air-fuel mixture inducted into the engine, thus affecting engine-out emissions. Accurate measurement of the RGF is cumbersome and expensive, thus making it hard to accurately characterize the initial mixture composition and temperature in any given engine cycle. This uncertainty can lead to challenges in accurately interpreting experimental emissions data and in implementing real-time control strategies. Quantifying the effects of the RGF can have important implications for the diagnostics and control of internal combustion engines. This paper reports on the use of a well-validated, two-zone quasi-dimensional model to compute the engine-out NO and CO emission in a gasoline engine. The effect of varying the RGF on the emissions under lean, near-stoichiometric, and rich engine conditions was investigated. Numerical results show that small uncertainties (~2–4%) in the measured/computed values of the RGF can significantly affect the engine-out NO/CO emissions.
{"title":"Sensitivity of Emissions to Uncertainties in Residual Gas Fraction Measurements in Automotive Engines: A Numerical Study","authors":"S. Aithal","doi":"10.1155/2018/7237849","DOIUrl":"https://doi.org/10.1155/2018/7237849","url":null,"abstract":"Initial conditions of the working fluid (air-fuel mixture) within an engine cylinder, namely, mixture composition and temperature, greatly affect the combustion characteristics and emissions of an engine. In particular, the percentage of residual gas fraction (RGF) in the engine cylinder can significantly alter the temperature and composition of the working fluid as compared with the air-fuel mixture inducted into the engine, thus affecting engine-out emissions. Accurate measurement of the RGF is cumbersome and expensive, thus making it hard to accurately characterize the initial mixture composition and temperature in any given engine cycle. This uncertainty can lead to challenges in accurately interpreting experimental emissions data and in implementing real-time control strategies. Quantifying the effects of the RGF can have important implications for the diagnostics and control of internal combustion engines. This paper reports on the use of a well-validated, two-zone quasi-dimensional model to compute the engine-out NO and CO emission in a gasoline engine. The effect of varying the RGF on the emissions under lean, near-stoichiometric, and rich engine conditions was investigated. Numerical results show that small uncertainties (~2–4%) in the measured/computed values of the RGF can significantly affect the engine-out NO/CO emissions.","PeriodicalId":44364,"journal":{"name":"Journal of Combustion","volume":"11 1","pages":"1-13"},"PeriodicalIF":0.7,"publicationDate":"2018-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76218827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The work is dedicated to the numerical study of detonation wave initiation and propagation in the variable cross-section axisymmetric channel filled with the model hydrogen-air mixture. The channel models the large-scale device for the utilization of worn-out tires. Mathematical model is based on two-dimensional axisymmetric Euler equations supplemented by global chemical kinetics model. The finite volume computational algorithm of the second approximation order for the calculation of two-dimensional flows with detonation waves on fully unstructured grids with triangular cells is developed. Three geometrical configurations of the channel are investigated, each with its own degree of the divergence of the conical part of the channel from the point of view of the pressure from the detonation wave on the end wall of the channel. The problem in consideration relates to the problem of waste recycling in the devices based on the detonation combustion of the fuel.
{"title":"Numerical Study of Detonation Wave Propagation in the Variable Cross-Section Channel Using Unstructured Computational Grids","authors":"A. Lopato, P. Utkin","doi":"10.1155/2018/3635797","DOIUrl":"https://doi.org/10.1155/2018/3635797","url":null,"abstract":"The work is dedicated to the numerical study of detonation wave initiation and propagation in the variable cross-section axisymmetric channel filled with the model hydrogen-air mixture. The channel models the large-scale device for the utilization of worn-out tires. Mathematical model is based on two-dimensional axisymmetric Euler equations supplemented by global chemical kinetics model. The finite volume computational algorithm of the second approximation order for the calculation of two-dimensional flows with detonation waves on fully unstructured grids with triangular cells is developed. Three geometrical configurations of the channel are investigated, each with its own degree of the divergence of the conical part of the channel from the point of view of the pressure from the detonation wave on the end wall of the channel. The problem in consideration relates to the problem of waste recycling in the devices based on the detonation combustion of the fuel.","PeriodicalId":44364,"journal":{"name":"Journal of Combustion","volume":"34 1","pages":"1-8"},"PeriodicalIF":0.7,"publicationDate":"2018-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73315222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carbon dioxide (CO2) is one of the greenhouse gases which cause global warming. The amount of fossil fuels consumed to meet the demands in the areas of power and transportation is projected to increase in the upcoming years. Depending on carbon content, each power plant fuel has its own potential to produce carbon dioxide. Similarly, the humans consume food containing carbohydrates (CH), fat, and protein which emit CO2 due to metabolism. The biology literature uses respiratory quotient (RQ), defined as the ratio of CO2 moles exhausted per mole of O2 consumed within the body, to estimate CO2 loading in the blood stream and CO2 in nasal exhaust. Here, we apply that principle in the field of combustion to relate the RQ to CO2 emitted in tons per GJ of energy released when a fuel is combusted. The RQ value of a fuel can be determined either from fuel chemical formulae (from ultimate analyses for most liquid and solid fuels of known composition) or from exhaust gas analyses. RQ ranges from 0.5 for methane (CH4) to 1 for pure carbon. Based on the results obtained, the lesser the value of “RQ” of a fuel, the lower its global warming potential. This methodology can be further extended for an “online instantaneous measurement of CO2” in automobiles based on actual fuel use irrespective of fuel composition.
{"title":"Ranking Renewable and Fossil Fuels on Global Warming Potential Using Respiratory Quotient Concept","authors":"K. Annamalai, S. Thanapal, Devesh Ranjan","doi":"10.1155/2018/1270708","DOIUrl":"https://doi.org/10.1155/2018/1270708","url":null,"abstract":"Carbon dioxide (CO2) is one of the greenhouse gases which cause global warming. The amount of fossil fuels consumed to meet the demands in the areas of power and transportation is projected to increase in the upcoming years. Depending on carbon content, each power plant fuel has its own potential to produce carbon dioxide. Similarly, the humans consume food containing carbohydrates (CH), fat, and protein which emit CO2 due to metabolism. The biology literature uses respiratory quotient (RQ), defined as the ratio of CO2 moles exhausted per mole of O2 consumed within the body, to estimate CO2 loading in the blood stream and CO2 in nasal exhaust. Here, we apply that principle in the field of combustion to relate the RQ to CO2 emitted in tons per GJ of energy released when a fuel is combusted. The RQ value of a fuel can be determined either from fuel chemical formulae (from ultimate analyses for most liquid and solid fuels of known composition) or from exhaust gas analyses. RQ ranges from 0.5 for methane (CH4) to 1 for pure carbon. Based on the results obtained, the lesser the value of “RQ” of a fuel, the lower its global warming potential. This methodology can be further extended for an “online instantaneous measurement of CO2” in automobiles based on actual fuel use irrespective of fuel composition.","PeriodicalId":44364,"journal":{"name":"Journal of Combustion","volume":"21 1","pages":"1-16"},"PeriodicalIF":0.7,"publicationDate":"2018-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77858943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The increasing energy consumption, mostly supplied by fossil fuels, has motivated the research and development of alternative fuel technologies to decrease the humanity’s dependence on fossil fuels, which leads to pollution of natural sources. Small-scale biomass gasification, using air-steam blends for partial oxidation, is a good alternative since biomass is a neutral carbon feedstock for sustainable energy generation. This research presents results obtained from an experimental study on coffee husk (CH) gasification, using air-steam blends for partial oxidation in a 10 kW fixed-bed gasifier. Parametric studies on equivalence ratio (ER) (1.53 < ER < 6.11) and steam-fuel (SF) ratio (0.23 < SF < 0.89) were carried out. The results show that increasing both SF and ER results in a syngas rich in CH4 and H2 but poor in CO. Also, decreased SF and ER decrease the peak temperature at the gasifier combustion zone. The syngas high heating value (HHV) ranged from 3112 kJ/SATPm3 to 5085 kJ/SATPm3 and its maximum value was obtained at SF = 0.87 and ER = 4.09. The dry basis molar concentrations of the species, produced under those operating conditions (1.53 < ER < 6.11 and 0.23 < SF < 0.89), were between 1.12 and 4.1% for CH4, between 7.77 and 13.49% for CO, and between 7.54 and 19.07% for H2. Other species were in trace amount.
以化石燃料为主的能源消费日益增长，促使替代燃料技术的研究和开发，以减少人类对化石燃料的依赖，从而导致自然资源的污染。使用空气-蒸汽混合物进行部分氧化的小规模生物质气化是一个很好的替代方案，因为生物质是可持续能源生产的中性碳原料。本研究提出了从咖啡壳(CH)气化的实验研究中获得的结果，在10kw固定床气化炉中使用空气-蒸汽混合物进行部分氧化。对等效比(ER) (1.53 < ER < 6.11)和蒸汽燃料比(SF) (0.23 < SF < 0.89)进行了参数化研究。结果表明:增加顺丰度和ER可生成富CH4和H2、低CO的合成气;减小顺丰度和ER可降低气化炉燃烧区峰值温度;合成气高热值(HHV)范围为3112 ~ 5085 kJ/SATPm3，在SF = 0.87、ER = 4.09时达到最大值。在这些操作条件下(1.53 < ER < 6.11和0.23 < SF < 0.89)， CH4的干基摩尔浓度为1.12 ~ 4.1%，CO为7.77 ~ 13.49%，H2为7.54 ~ 19.07%。其他物种则是微量的。
{"title":"Adiabatic Fixed-Bed Gasification of Colombian Coffee Husk Using Air-Steam Blends for Partial Oxidation","authors":"J. Bonilla, G. Gordillo","doi":"10.1155/2017/3576509","DOIUrl":"https://doi.org/10.1155/2017/3576509","url":null,"abstract":"The increasing energy consumption, mostly supplied by fossil fuels, has motivated the research and development of alternative fuel technologies to decrease the humanity’s dependence on fossil fuels, which leads to pollution of natural sources. Small-scale biomass gasification, using air-steam blends for partial oxidation, is a good alternative since biomass is a neutral carbon feedstock for sustainable energy generation. This research presents results obtained from an experimental study on coffee husk (CH) gasification, using air-steam blends for partial oxidation in a 10 kW fixed-bed gasifier. Parametric studies on equivalence ratio (ER) (1.53 < ER < 6.11) and steam-fuel (SF) ratio (0.23 < SF < 0.89) were carried out. The results show that increasing both SF and ER results in a syngas rich in CH4 and H2 but poor in CO. Also, decreased SF and ER decrease the peak temperature at the gasifier combustion zone. The syngas high heating value (HHV) ranged from 3112 kJ/SATPm3 to 5085 kJ/SATPm3 and its maximum value was obtained at SF = 0.87 and ER = 4.09. The dry basis molar concentrations of the species, produced under those operating conditions (1.53 < ER < 6.11 and 0.23 < SF < 0.89), were between 1.12 and 4.1% for CH4, between 7.77 and 13.49% for CO, and between 7.54 and 19.07% for H2. Other species were in trace amount.","PeriodicalId":44364,"journal":{"name":"Journal of Combustion","volume":"1 1","pages":"1-10"},"PeriodicalIF":0.7,"publicationDate":"2017-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2017/3576509","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72402479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Z. Peng, T. Megaritis, C. Sung, M. Yaga, P. Hellier, G. Tian
The transport sector accounts for a significant part of carbon emissions worldwide, and so the need to mitigate the greenhouse effect of CO 2 from fossil fuel combustion, and to reduce vehicle exhaust emissions has been the primary driver for developing cleaner and more efficient vehicle powertrains, and environmentally friendly fuels.
{"title":"Advanced engine flows and combustion","authors":"Z. Peng, T. Megaritis, C. Sung, M. Yaga, P. Hellier, G. Tian","doi":"10.1155/2017/9285097","DOIUrl":"https://doi.org/10.1155/2017/9285097","url":null,"abstract":"The transport sector accounts for a significant part of carbon emissions worldwide, and so the need to mitigate the greenhouse effect of CO 2 from fossil fuel combustion, and to reduce vehicle exhaust emissions has been the primary driver for developing cleaner and more efficient vehicle powertrains, and environmentally friendly fuels.","PeriodicalId":44364,"journal":{"name":"Journal of Combustion","volume":"59 1","pages":"1-3"},"PeriodicalIF":0.7,"publicationDate":"2017-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80479690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Bai, Zuowei Zhang, Yongchen Du, Fan Zhang, Zhijun Peng
When multi-injection is implemented in diesel engine via high pressure common rail injection system, changed interval between injection pulses can induce variation of injection rate profile for sequential injection pulse, though other control parameters are the same. Variations of injection rate shape which influence the air-fuel mixing and combustion process will be important for designing injection strategy. In this research, CFD numerical simulations using KIVA-3V were conducted for examining the effects of injection rate shape on diesel combustion and emissions. After the model was validated by experimental results, five different shapes (including rectangle, slope, triangle, trapezoid, and wedge) of injection rate profiles were investigated. Modeling results demonstrate that injection rate shape can have obvious influence on heat release process and heat release traces which cause different combustion process and emissions. It is observed that the baseline, rectangle (flat), shape of injection rate can have better balance between NOx and soot emissions than the other investigated shapes. As wedge shape brings about the lowest NOx emissions due to retarded heat release, it produces the highest soot emissions among the five shapes. Trapezoid shape has the lowest soot emissions, while its NOx is not the highest one. The highest NOx emissions were produced by triangle shape due to higher peak injection rate.
{"title":"Effects of Injection Rate Profile on Combustion Process and Emissions in a Diesel Engine","authors":"F. Bai, Zuowei Zhang, Yongchen Du, Fan Zhang, Zhijun Peng","doi":"10.1155/2017/9702625","DOIUrl":"https://doi.org/10.1155/2017/9702625","url":null,"abstract":"When multi-injection is implemented in diesel engine via high pressure common rail injection system, changed interval between injection pulses can induce variation of injection rate profile for sequential injection pulse, though other control parameters are the same. Variations of injection rate shape which influence the air-fuel mixing and combustion process will be important for designing injection strategy. In this research, CFD numerical simulations using KIVA-3V were conducted for examining the effects of injection rate shape on diesel combustion and emissions. After the model was validated by experimental results, five different shapes (including rectangle, slope, triangle, trapezoid, and wedge) of injection rate profiles were investigated. Modeling results demonstrate that injection rate shape can have obvious influence on heat release process and heat release traces which cause different combustion process and emissions. It is observed that the baseline, rectangle (flat), shape of injection rate can have better balance between NOx and soot emissions than the other investigated shapes. As wedge shape brings about the lowest NOx emissions due to retarded heat release, it produces the highest soot emissions among the five shapes. Trapezoid shape has the lowest soot emissions, while its NOx is not the highest one. The highest NOx emissions were produced by triangle shape due to higher peak injection rate.","PeriodicalId":44364,"journal":{"name":"Journal of Combustion","volume":"1 1","pages":"1-8"},"PeriodicalIF":0.7,"publicationDate":"2017-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83731474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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