An artificial neural network framework for gasification of liquid fuels under oxy-fuel conditions

Gasification is a clean thermochemical process which converts carbon-based fuels into syngas. In this work, an artificial neural network model of heavy oil gasification under different gasifying agents was developed. Model was validated with the experimental data from literature. Effect of important parameters such as equivalence ratio and oxygen ratio (OR) on the higher heating value (HHV) of the produced syngas, gasification efficiency (GE), carbon conversion efficiency (CCE) was studied. With OR increasing from 0.366 to 0.41, GE and syngas HHV decreased, but CCE increased.     

Effects of residence time and heating rate on gasification of petroleum residue

Gasification of petroleum residue has been considered as the potential technology due to the advantages of converting the liquid fuels into syngas using partial oxidation. In this paper, we developed a one-dimensional kinetic model to simulate the effects of residence time and heating rate on the gasification characteristics. Results showed that gasification under higher heating rate improves the hydrogen yield and carbon conversion efficiency. It was also found that the residence time plays a major role in the process; higher residence time improves the hydrogen yield and gasification efficiency. The model was validated against the reported data and found to be in good agreement.     

A Comprehensive Study on Gasification of Petroleum Wastes Based on a Mathematical Model

Gasification is a thermochemical process that produces useful and environmentally friendly by-products. Here the effects of various parameters such as equivalence ratio, pressure, and steam gasifying on the gasification process of waste lubricant oil are investigated based on Gibbs free energy minimization approach. The model is validated by reported data and found to be in good agreement. Various gasification performance parameters such as cold gas efficiency, carbon conversion efficiency, gasification temperature, pressure, and heating value of produced gas were determined based on a parametric study. The use of CaO catalyst has also been investigated for the production of hydrogen-rich gas with in situ CO₂ capture in steam gasification of waste oil. The results indicate that an appropriate steam/fuel ratio and more catalyst are favorable for getting a higher H₂ ratio and a lower CO₂ output.     

Computer-based model of crude oil gasification in a fluidized bed

Gasification is a high-temperature, low-cost, and environmentally friendly process with uses as an alternative method to convert the carbon-based fuels into a clean syngas for engineering applications. In this work, the authors developed a mathematical model of crude oil for evaluating the crude oil potential to produce a clean and high caloric value syngas. The influence of some critical parameters during crude oil gasification including equivalence ratio, excess oxygen ratio (EOR), and residence time on tar yield, syngas caloric value, and char conversion was investigated. Results showed that with increasing the EOR, the char was converted continuously due to a significant improvement in the nature of endothermic reactions involved. It is also found that when the EOR increases from 0.2 to 0.8, gas caloric value improves, slightly.     

A computational fluid dynamic model for evaluating the performance of crude oil gasification

Gasification is a clean technology which converts the liquid or solid fuels into a high caloric value syngas for power generation. In this research work, we developed a computational fluid dynamic model of crude oil gasification for hydrogen production; the accuracy of the model was approved in our previous work. Effects of some important factors such as residence time, steam/fuel ratio and equivalence ratio on hydrogen yield, and char conversion were explored. Results showed that the residence time and steam/fuel ratio play a major role in the process. It was also found that the equivalence ratio has a negative effect on the hydrogen yield and a positive effect on the char conversion.     

A parametric study for gasification of liquid fuels

Gasification is a clean technology for production of high caloric value syngas. In this study, a kinetic model of gasification of heavy oil is developed to investigate the influence of oxygen ratio and pressure on the quality of syngas and performance parameters. Results showed that the oxygen ratio improves the caloric value of syngas and gasification efficiency, and also found that the pressure has a minor effect on the process. The model was validated against experimental data and found to be in good agreement.     

Aspen plus simulation of heavy oil gasification in a fluidized bed gasifier

Gasification is a clean technology to convert fuels to high-quality syngas in presence of a gasifying agent. In this study, an Aspen Plus model of heavy oil gasification was developed to produce the hydrogen rich syngas. Effect of some parameters such as gasification temperature and steam/fuel ratio on the hydrogen yield and was investigated. Results showed that the temperature plays a major role in the process; higher temperatures produce the higher hydrogen content. It was also found that the operation under high steam/fuel ratio can cause a significant increase in the hydrogen yield. The modeling results were compared with the experimental data available in the literature and found to be in good agreement.     

Aspen Plus simulation of steam-gasification of different crude oils: A detailed comparison

The gasification process is being developed to obtain environmentally clean and efficient syngas from solid (coal, biomass, and municipal solid waste) or liquid (heavy oil and waste lubricant oil) fuels for power generation. An Aspen Plus model of crude oil gasification in presence of steam as a gasifying agent that can predict syngas yield, tar concentration, and performance parameters was developed. Effects of some critical parameters such as gasification temperature, steam-fuel-ratio on hydrogen yield, tar content, and char conversion of three different crude oils were explored. Results showed that the hydrogen yield increases by increasing steam/fuel ratio from 0.5 to 0.7 (wt/wt), and then reduces smoothly due to the endothermic behavior of methane reforming reaction, which releases three hydrogen moles. It also found that as the temperature increases within the range, hydrogen yield increases dramatically, which can be explained according to the Le Chatelier's principle on the endothermic reforming reactions of methane and tar cracking. Modeling results validated against the experimental measurements and found to be in a good agreement.     

Hydrogen production from co-gasification of asphaltene and plastic

At present, due to the environmental considerations and world energy crisis, there is a growing trend towards using gasification instead of combustion as a thermochemical route for power generation. The purpose of this work was to provide a computer-based model to predict the potential of gasification process for syngas production. The influence of the most important operational conditions namely asphaltene/plastic mass ratio (A/P), steam/fuel ratio (S/F), gasification temperature (T_gas), and equivalence ratio (ER) on gas composition and tar concentration was evaluated. With the asphaltene/plastic ratio (A/P) increasing from 0.2 (wt/wt) to 0.6 (wt/wt), the carbon conversion efficiency (CCE) initially increases from 47.88% to 54.61% for S/F = 0.25, from 49.80% to 54.11% for S/F = 0.5, from 51.83% to 58.36% for S/F = 0.75, and from 52.69% to 60.57% for S/F = 1.0, then steadily decreased. The gas yield also increased from 45.12 (%) to 92.08 (%) with increasing ER from 0.1 to 0.8, while the tar yield decreased from 12.24 (%) to 00.14 (%).     

基于铁基载氧体的市政污泥气化特性模拟及实验研究

基于Aspen Plus软件中的模拟及流化床反应器中的部分实验,研究了铁基载氧体在市政污泥化学链气化中对碳转化效率、合成气组分、硫氮污染物排放等特性的影响。结果表明：燃料反应器中氧/碳摩尔比(n(O)/n(C))的增加提高了污泥的碳转化率,但却降低了CO、H2的浓度,碳转化率趋于平稳时明显减少了羰基硫(COS)和H2S的排放;燃料反应器中温度的提升利于合成气热值和污泥气化率的提高,降低H2S排放量的同时增加SO2的生成;随着水蒸气与污泥质量流量比的增加,H2的摩尔分数明显上升,在其质量流量比超过12时,变化不再明显;空气反应器中空气与载氧体摩尔流量比(空载比)的增加会使载氧体再生程度提高,但空载比增加到1.3时,开始有大量NOx的生成;空气反应器中反应温度的升高对载氧体的再生影响不大,但会导致热力型NOx的产生。     

低阶煤固定流化床热解及半焦气化实验研究

采用固定流化床研究了三种低阶煤的常压热解及其热解半焦的气化特性,探究了样品粒度、反应温度、反应时间及流化气中O2含量对上述过程的影响,确定了循环流化床热解-气化耦合工艺适宜的反应条件。结果表明,在实验选择范围内,样品的粒度基本不会影响热解过程,在水蒸气气氛下,温度越高,热解气体产率越高,半焦产率越低;600 ℃和20 min时能获得最高的焦油产率。循环流化床热解-气化耦合工艺碳的有效利用率率高于原煤固定流化床气化工艺,同时副产煤焦油;温度越高,有效气产率和有效碳转化率越高;实验范围内,O2含量对合成气产率的影响较小,但可以调节H2和CO的相对含量;900 ℃、半焦气化15 min即可获得较理想的合成气产率及有效碳转化率。     

Thermodynamic evaluation of mazut gasification for using in power generation

In this study, gasification of mazut, as a heavy fuel oil with high sulfur content, is studied by an equilibrium model. Effects of equivalence ratio and adding steam as a gasifying agent on gasifier performance are studied. It was found that for highest cold gas efficiency, equivalence ratio and H₂O/fuel ratio are 0.3 and 0.2, respectively. Based on these findings, it was estimated that using 31 kg/sec mazut, 445 MW electricity can be produced in an integrated gasification combined cycle. It also conclude that all produced mazut in Iran's refineries has the potential of 11000 MW power generation.     

基于Aspen Plus的生物质化学链气化耦合CO2裂解模拟研究

生物质化学链气化耦合CO₂裂解技术能够在产生高品质合成气的同时将CO₂转化为CO,是可以同步实现CO₂增量降低和存量减少的有效手段之一。使用Aspen Plus软件,建立了生物质化学链气化耦合CO₂裂解过程的模型,研究了温度、压力和生物质与氧载体质量比(m(Biomass)/m(Oxygen carrier),简称m_B/m_O)对反应产出合成气组分、气化特性参数和系统热负荷的影响。结果表明：随着温度的升高,反应产出的合成气中CO、H₂含量呈现上升趋势,CO₂、CH₄含量下降,产气热值增大,且在高于800 ℃时趋于稳定,反应温度在1000 ℃以下时,系统产热可以满足反应需要;当反应压力由0.1 MPa提高至0.5 MPa时,H₂、CO含量下降,CO₂含量提高,合成气热值下降,系统整体放热量增大;当m_B/m_O增大时,生物质进料量逐渐增多,氧载体还原产物中Fe含量增大,FeO含量降低,合成气热值上升;当m_B/m_O在0.3~1.3区间内时,系统产热可以满足系统反应所需。耦合CO₂裂解反应器后碳转化率有较大提升,并且在m_B/m_O为0.7时提升最为显著。     

Mathematical modeling of unsteady-state gasification of petroleum residue

Gasification is a thermochemical process which converts organic fuels into a high caloric value syngas and other chemicals in the presence of a gasification agent. Tar generation represents the strongest barrier for the use of fixed-bed reactors for liquid fuel gasification, whereas sufficing is only possible with catalytic activities and expensive physical processing. In this work, a kinetic model of waste oil gasification was proposed which can be used a flexible model to provide a quantitative prediction of product yield of other fuels. Results were validated against the experimental measurements and showed a good agreement. In accordance with the modeling results, it was found that the greenhouse gas emission (GGE) of waste oil is higher than that of biomass materials, but the caloric value of the syngas generated is higher. The residence time was also recognized as an important design parameter to improve the syngas volume fraction.     

喷嘴结构对粉煤气化过程影响的数值模拟

为研究气化喷嘴对气流床干煤粉气化炉气化过程的影响规律,并对喷嘴结构进行优化,针对具有不同煤粉通道旋转角θ和旋流叶片安装角度α值气化喷嘴的气化炉建立三维模型并进行数值模拟。通过冷态模拟发现：气化室内流体的速度场主要受α值的影响,而θ值对气化室内煤粉颗粒的质量浓度影响更加明显。当θ=60°、α=30°时,煤粉颗粒的弥散性最好,气化室内流体的速度分布、煤粉颗粒的质量浓度以及气化剂分布更加均匀,有利于气化炉气化效率的提高。取喷嘴结构参数θ=60°、α=30°的模型进行气化过程热态模拟,辐射传热采用P-1模型、湍流-化学反应过程采用EDC模型、脱挥发分采用Two-Competing Rates模型。模拟结果显示,该喷射条件下气化室内的流场分布好,气化效率高,合成气有效气组分CO+H₂总摩尔分数达到91.6%,碳转化率达到98.11%。     

A kinetic model for gasification of heavy oil with in situ CO2 capture

Gasification process is being developed to obtain environmentally clean and efficient syngas from solid (coal, biomass, and municipal solid waste) or liquid (heavy oil and waste lubricant oil) fuels for power generation. A gasification kinetic model of heavy oil in the presence of CaO that can predict syngas yield, tar concentration, and performance parameters has been developed. Results showed that the CaO plays a major role for a significant reduction in carbon dioxide during the process. Based on the operating conditions, it was also found that there is an optimum condition for tar yield. Modeling results were validated against experimental data and found to be in good agreement.     

化学链气化过程中昭通褐煤灰对锰矿石载氧体的影响

为探究化学链气化过程中煤灰及其组分对锰矿石载氧体的影响及作用机理,制备了昭通褐煤煤灰,以煤灰中主要组分Fe₂O₃、CaO和MgO等氧化物颗粒配制单一及混合组分的模拟煤灰,在高温流化床反应器中以水蒸气为气化剂进行了系列研究。结果表明：添加5%(质量分数)褐煤煤灰后,合成气产量升高而碳转化率降低,且随着煤灰添加量的继续增多,合成气产量呈先降低后升高趋势,而碳转化率则呈现先升高后降低趋势,在煤灰添加质量分数为15%时,出现最高的碳转化率79.7%和最低的合成气产量0.702 L。Fe₂O₃组分明显提高了碳转化率和合成气产量;CaO与Mn₂O₃高温反应生成了Ca₂Mn₂O₅,提高了载氧体选择性,使得合成气产量增大;MgO显著降低了碳转化率和合成气产量。双组分及MgO-Fe₂O₃-CaO三组分模拟煤灰的研究发现,MgO对气化反应进程抑制作用强于Fe₂O₃和CaO的促进作用,相比于Fe₂O₃-MgO双组分模拟煤灰,CaO-MgO模拟煤灰对载氧体气化活性的抑制作用影响最大。     

Modeling Steam Gasification of Orimulsion in the Presence of KOH: A Strategy for High-Yield Hydrogen Production

Production of hydrogen rich gases from heavy oils via potassium-catalyzed steam gasification is a promising approach toward cleaner fuel production, suitable for fuel cell applications. The authors developed a zero-dimensional mathematical model to simulate the steam gasification of Orimulsion with KOH as a catalyst, based on an equilibrium model. The model is compared with the numerical results and data from an experimental study, showing a good agreement with it. This research activity presents a large number of predicted data of catalytic gasification, aiming to survey the effects of reaction temperature, gasification pressure, steam/fuel ratio, and KOH/fuel ratio on gas product compositions. It also provides useful indications for its optimal choice. Results illustrate that the pressurized operation slightly increases methane concentration as well as the production of higher heating value gas, while decreasing the hydrogen concentration.     

1 MWth 煤化学链气化过程模拟

基于Aspen Plus建立了1 MWth煤化学链气化模型,探讨了气化过程中不同煤种(宁夏煤、新疆煤、云南煤)、不同载氧体(赤铁矿、锰矿)、温度、氧/碳摩尔比、压力、水蒸气/煤质量比对合成气组分的影响及实现系统自热平衡运行的条件。结果表明：在700~1200 ℃范围内,随着反应温度升高,3种煤合成气产率及冷煤气效率先增加后趋于平缓;水蒸气/煤质量比在0.5~1.5范围内增大、压力在0.1~3.0 MPa范围内增加都会使合成气产率降低;随氧/碳摩尔比在0.1~1.7范围内增大,合成气产率显著降低,系统由外部供热变为向外放热;当系统实现自热平衡运行时,赤铁矿和天然锰矿载氧体的氧/碳摩尔比分别为1.1和1.5;在保证反应速率和经济成本的前提下,优先选择天然锰矿石作为载氧体。     

Effect of equivalence ratio on gas distribution and performance parameters in air-gasification of asphaltene: A model based on Artificial Neural Network (ANN)

Air-gasification of asphaltene was carried out in a bench scale fluidized bed. A neural network model was also developed to study the influence of equivalence ratio (ER) on gas distribution, lower caloric value (LHV) of producer gas, and performance indicators (char conversion and cold gas efficiencies). The contents of CO and H₂ were initially increased from 53.2 to 55.4?vol% and 35.4 to 37.6?vol% as ER increased to 0.35, and then decreased to 43.3?vol% and 27.7?vol% at ER of 0.5, respectively. The results also indicated that the LHV of the produced syngas was significantly decreased with ER increasing because of more oxidation reactions at higher ERs.