A BIOMASS PYROLYSIS GASIFIER APPLICABLE TO RURAL CHINA

Abstract

A pyrolsis gasifier was developed to make use of indigenous biomass to help solve the problem of rural energy shortage particularly in engine fuel shortage and to reduce pollution. First, (low diagram of pyrolysis gasification system was designed and the sketch of gasifier was drawn. Second, the gasifier thus drawn was made. It was successfully operated with corncob feeding. Its performance parameters were measured in an experimental scheme designed according to an orthogonal test table. A variance analysis was taken of the results were taken to sort out the best experimental condition. A run on such conditions gave a heating value of the gas as high as 12.4MJ/nm³ and without tar, a conversion rate about 60.2%, and a total energy efficiency about 59.3%. Regressive analysis of the data that shows the flow rate of the gas is an exponential function of time. Finally, explanations to the analysis results of the data and what problems of the gasiSSfier to be tackled were given.     

低阶煤流化床热解气化新工艺

针对低阶煤流化床热解气化所遇到的问题,对热解炉供热模式、原料煤粒径与颗粒分级、热解气初级冷却与除尘、排灰方式等问题进行探讨,优化工艺过程。新工艺中选择高温半焦为热解炉提供热量,将原料煤磨制成亚毫米级粉粒,磨煤产生的少量粒径小于0.1 mm的细颗粒被分离出来,送往配套的气流床气化炉,与流化床气化炉气体带出的细粉一起进行熔渣气化,提高碳转化率。大量粒径为0.1~1.0 mm的颗粒进热解炉,热解炉出来的气体经适当馏分煤焦油冷却、捕集颗粒物,使温度降至350 ℃左右,采用间接换热模式进一步降温,由此将有机废水产量降至近零水平,实现清洁高效热解气化。以低阶煤4 600 t/d规模的流化床热解气化新工艺为例,干基煤粗粉进热解炉,干燥单元取水约480 kt/a,热解单元不产生有机废水,可产有效气体（氢气和一氧化碳）约1.09×10⁹ m³/a,产煤焦油约81 kt/a,系统碳转化率大于95%,煤焦油、煤气、半焦的产率分别为8.97%,110 m³/t,67.5%,半焦气化产物气中有效气体积分数大于80%。     

Hydrogen production by catalytic gasification of petroleum residue

The liquid fuel gasification to obtain a clean flue gas for power generation and produce chemicals such as methanol is a most promising attempt to reduce the greenhouse gas emissions and air pollutants. In this paper, an equilibrium model of liquid fuel gasification was developed by the method of Gibbs free energy minimization. Two kinds of catalysts: Ni/CeO₂/Al₂O₃ and Ni/Al₂O₃ were used to explore the influence of catalysts and operating conditions on hydrogen yield and char conversion. Over the ranges of operating conditions studied, the maximum hydrogen yield reached 52.47 vol%, whereas the char conversion varied between 45.2% and 98.5%. The results indicated that an appropriate reaction temperature is favorable for higher hydrogen production and char conversion. The model was validated with experimental data obtained from a fluidized bed gasifier.     

对甲酚氧化合成对羟基苯甲醛

研究了对甲酚经空气氧化合成对羟基苯甲醛反应过程。研究发现，在试验条件下对甲酚氧化反应是受氧传质控制的反应。通过使用特制的气体分布器，可以有效地强化传氧速度，提高总反应速度。从拟一级反应模型出发，提出该氧化反应的宏观动力学方程，计算了反应的表观活化能。     

甲烷在活性炭上的吸附平衡及充气试验

为探索缓解家庭用ANG储罐在使用过程中受热效应影响的热管理措施,在温度区间263.15K～313.15K、压力范围0MPa～8MPa,测试了甲烷在比表面积为2074m2.g-1的SAC-02椰壳活性炭上的吸附平衡数据,并由Toth方程确定了相应的绝对吸附等温线。其次,在室温、3.5MPa、5L.min-1～25L.min-1的甲烷流率下,对装填有390g活性炭、中心区域布置U型换热管的储罐进行充气试验。结果表明,Toth方程在试验范围内的预测相对误差小于3.25%;储罐吸附床压力的上升速率是影响实际充气流率、吸附床温度变化和充气总量的关键因素;在试验范围内,U型管内循环30℃的冷却水可降低吸附床的平均温度和最大温升约3.6℃和7.3℃,但仅能提高约6.5%的总充气量。Toth方程可用于分析甲烷在活性炭上的吸附平衡,延长储罐吸附床压力上升至充气压力的时间可改善ANG储罐的充气性能。     

天然气非催化部分氧化制合成气过程的研究

以多通道喷嘴为射流源,在1m×6m的大型冷模装置中测定了天然气非催化部分氧化气化炉内的流体流动过程、冷态浓度分布和停留时间分布。分析了气化炉内各流动区域的化学反应过程,以工业操作数据为基础对天然气非催化部分氧化过程进行了分析和模拟,探讨了工艺条件对转化反应结果的影响。模拟研究结果表明,在射流区主要为燃烧反应,在管流区主要为转化反应;合成气的产量随氧气和天然气体积比的变化会出现最大值,随天然气组成的不同,对大型气炉适宜的氧气和天然气体积比为0.66~0.68,对小型气炉适宜的氧气和天然气体积比为0.68~0.70。当氧气与天然气体积比达到0.67之后,蒸汽的加入对合成气产量和气化炉出口气体中CH4的含量几乎无影响。     

煤气发生炉出口余热回收

为有效降低煤气发生炉出口的煤气温度（500～600℃）,节约能源,减少其对环境的污染并利用这部分热量,在煤气发生炉出口设置余热回收热交换器,利用高温煤气来加热给水产生低压水蒸气,供生活使用。在热交换器负荷改变的情况下进行了不同工况的设计计算。结果表明,对于给定的结构参数,煤气处理量增加时,热交换器的传热性能提高。在煤气发生炉出口设置热交换器后,煤气出口温度显著降低,减少了热量浪费,并且减少了对环境的污染破坏。     

保压岩心油气水饱和度分析及脱气校正方法研究

本文了保压岩心油气水饱和度分析技术、实验条件与数据处理方法，研究并建立了岩心准备、气体收集、全直径岩心饱和度分析、洗油等系统流。据大庆长垣２口保压密闭取心井油气水饱和度资料，绘制了不同油层油水饱和度脱气校正图版，经过比，油水饱和度由常规的８８％，提高到９６％以上，平均提高８％。     

气井连续携液机理

平行气流中的液滴趋于椭球状,而低黏度液滴临界韦伯数 We_crit 相差较大,在2.2~60变化,而已有的携液模型未综合考虑液滴变形和液滴尺寸差异对气井临界携液气量的影响。根据液滴质点力平衡理论,笔者导出了气井临界携液气量预测新模型。新模型引入的特征参数 C_k,Wecrit 综合考虑了液滴变形和最大液滴尺寸差异对携液气量的影响。根据一般能量守恒原理,推导出了液滴变形程度与临界韦伯数的函数关系,计算结果与实验数据和DDB模型预测结果一致,误差小于6%。新模型的关系式系数 C_k,Wecrit 在2.14～4.79变化,而根据文献数据和国内气田临界气流量反算的系数 C_k,Wecrit 在1.86~5.0变化。新模型从机理上解释了各气田临界携液气量相差较大和个别气田临界携液气量较低的原因,并以大牛地气田为例介绍了该模型的应用。     

以太阳能为高温热源的LNG卫星站冷能发电系统

如何高效合理利用LNG所携带的冷能一直是人们关注的话题。为此,对LNG卫星站中LNG冷能利用方式及工艺流程进行了研究。以山东淄博LNG卫星站为例,建立了一种以太阳能加热的水为高温热源,LNG储罐输出的LNG液态工质为低温热源的热力循环发电系统。设计了该系统的工艺参数,计算了该系统日均净发电量和能量利用效率,分析了该系统的经济性和环保效益。结果表明：在日供气量为12×10⁴ m³的山东淄博LNG卫星站中建立该热力循环系统,能量利用效率可超过30%且符合工程实际,年可发电27×10⁴ kW·h,每年带来约30万元的经济效益;同时,还可以节约气化LNG所需的燃料费用6～8万元/a,减少因燃烧煤炭和天然气而带来的400～1 000 kg/a的SO₂排放量和56～146 t/a的CO₂排放量,实现了节能、环保、增效三赢。     

CATALYTIC CRACKING OF TARS FROM COAL DEVOLATILIZATION

A set of runs were performed on the catalytic and thermal cracking of the tars present fn the gasifier off-gas stream; the cracking referred to here Js essentially hydrocracking, in view of the considerable amount of hydrogen being present in the gas stream. The catalyst evaluated for tar cracking was a commercial cobalt-molybdenum catalyst, suppported on γ-Al₂O₃(Katalco-477). It was observed that there was a decrease in the amount of tar obtained with the cracking unit on-line with the gasifier; the tars were cracked to gaseous products in the presence of catalyst. Furthermore, it appeared that higher ring structures were transformed to less heavier components; thus cracking could become beneficial in downstream processing of the gas stream coming out of a gasifier.     

热管式生物质气化炉的研究

将高温热管技术引入生物质气化中,开发了一种间接供热的热管式生物质气化炉,对高温热管的传热性能和4种生物质原料(木屑、玉米秆、稻壳和稻草)的水蒸气气化特性进行了研究。实验结果表明,气化炉内床层轴向和径向温度的变化趋势与高温热管启动温度的变化趋势基本一致。反应温度和原料种类影响气体产物的组成。在反应温度为650～950℃时,4种原料的气体产物中H2体积分数均为50%～60%,且随反应温度的升高而增加,H2含量增长率的大小顺序为:木屑>玉米秆>稻壳>稻草;CO2体积分数为15%～30%,且随反应温度的升高而减少,木屑和玉米秆的气体产物中CO2含量高于稻壳和稻草;CO和CH4含量随反应温度的升高变化较小,原料种类对CH4含量影响较小,稻壳和稻草的气体产物中CO含量比木屑和玉米秆高。     

A MODEL OF A PYROLYSIS GASIFIER FOR PREDICTION COMPOSITIONS AND FLOU RATE OF PRODUCED GAS

A model of pyrolysis gasifier, which is mainly composed of a pyrolysis, a cracking and a combustion chamber, it developed to predict its performance parameters and to simulate its operation. Toe model consists of a pyrolysis-cracking sub-model, a secondary gasification sub-model and a combustion sub- model, of which the pyrolysis-cracking sub-model is modified to predict components of tbe pyrolysis gas. Then, It with the other two sub-models can predict components, heating value and flow rate of the produced gas, thermal efficiency and total energy efficiency of the gasifier as ell. Crank-Nicolson Scheme (half implicit difference formulation) in which the time step is not confined by stability and the cutting error is small, is applied to solving the model whose differential equations are nonlinear and have no analytic solution. Theo, the nonlinear difference algebraic equations are solved by interalions, which requires less storage of computer. Underrelaxation is applied to avoiding divergence of Causs-Seidel interations. Finally, the simulated results are input to Software Lotus 1-2-3, by which the results are printed and graphed so as to compare with the experimental ooes, and it shots acceptable agreement, thus validate the model.     

A MODEL OF A PYROLYSIS GASIFIER FOR PREDICTION COMPOSITIONS AND FLOU RATE OF PRODUCED GAS

ABSTRACT

A model of pyrolysis gasifier, which is mainly composed of a pyrolysis, a cracking and a combustion chamber, it developed to predict its performance parameters and to simulate its operation. Toe model consists of a pyrolysis-cracking sub-model, a secondary gasification sub-model and a combustion sub- model, of which the pyrolysis-cracking sub-model is modified to predict components of tbe pyrolysis gas. Then, It with the other two sub-models can predict components, heating value and flow rate of the produced gas, thermal efficiency and total energy efficiency of the gasifier as ell. Crank-Nicolson Scheme (half implicit difference formulation) in which the time step is not confined by stability and the cutting error is small, is applied to solving the model whose differential equations are nonlinear and have no analytic solution. Theo, the nonlinear difference algebraic equations are solved by interalions, which requires less storage of computer. Underrelaxation is applied to avoiding divergence of Causs-Seidel interations. Finally, the simulated results are input to Software Lotus 1-2-3, by which the results are printed and graphed so as to compare with the experimental ooes, and it shots acceptable agreement, thus validate the model.     

天然气能量计量体系在中国的建设和发展

天然气贸易交接中的计量方式通常有三种,即体积计量、质量计量和能量计量。由于能量计量反映的是天然气的热能,作为最能反映其燃料特点的一种合理和科学的计量方式,在天然气国际贸易中被广泛采用。然而,中国目前尚普遍采用以体积流量作为贸易结算的依据。2008年12月31日,中国国家标准化管理委员会发布GB／T22723—2008《天然气能量的测定》国家标准,并于2009年8月1日起正式实施。依据GB／T22723—2008在实施范围和对象、能量计量方法、标准参比条件和能量计量体系方面的要求,深入分析中国天然气能量计量体系在天然气能量计量标准体系、能量计量相关设备的配置和性能评价、体积流量和发热量量值溯源链、标准参比条件和结算单位等方面的建设现状,并通过3个天然气长输管道A级计量站天然气能量计量技术的应用实例,（该3个A级计量站发热量测定均达到了GB／T18603—2001《天然气计量系统技术要求》对A级计量站0．5％的不确定度水平要求）,表明中国已具备实施天然气能量计量的基础条件。为了进一步推动中国天然气能量计量体系的发展,本文还讨论了全面实施能量计量还存在的一些不足,提出当前最重要的是应尽快形成甲烷不确定度0．05％、其它少量组分不确定度0．5％的国家一级天然气分析用多组分（九元）气体标准物质,建立不确定度为0．25％的发热量直接9n,4定装置,达到ISO15971：2008〈天然气性质测定发热量和沃泊指数》规定的一级水平,完善天然气体积流量和发热量量值溯源链,制定天然气溯源标准和能量测定系统性能评价标准,促进天然气能量计量技术在中国的全面实施。     

Hot-brine Injection for the Dissociation of Natural Gas Hydrates

A new one-dimensional experimental system for natural gas hydrate (NGH) exploitation is designed, which is used to study the formation and dissociation processes of NGH. NGH is formed in the sand-packing tube, and then hot-brine is injected into the tube to study the thermal dissociation characteristics. The injection parameters that influence gas production rate and energy efficiency are analyzed. The results show that the higher the injection temperature and injection rate are, the higher the gas production rate is. In addition, the most sensitive parameter, which influences the energy efficiency of thermal stimulation is the hot-brine temperature, followed by the hot-brine injection rate and injection time. This study provides an experimental basis for further study on NGH exploitation in the future.     

减压渣油热转化集总动力学的建模研究

以洛阳减压渣油为例,研究了减压渣油热转化集总动力学模型.对洛阳减压渣油分别在410、420、430和440℃下进行的热转化反应,通过数学分析建立了6集总动力学反应模型.减压渣油热转化反应生成裂化气、汽油、轻瓦斯油、重瓦斯油与焦炭,其反应均为2级反应;轻、重瓦斯油将继续发生2次反应,生成焦炭;动力学参数中缩合反应的活化能大于裂化生成馏分油的活化能,表明缩合反应对反应温度的变化更为敏感.计算结果表明,所建模型可以用来预测减压渣油热转化反应产物分布,预测值与实验值吻合较好.     

中美天然气现行价格水平及走势比较分析

近几年,随着气荒现象的频繁出现,天然气供需和价格问题成为社会各界普遍关注的焦点。随着美国页岩气大规模的开发,美国天然气价格出现了大幅度跳水,由2008年的约2200元/103m3下降到2009年的约980元/103m3;而我国在经历了2010年天然气价格改革后,目前天然气井口基准价由之前大大低于美国到目前高出美国约30%。在对大量最新数据的研究和分析的基础上,以中美两国天然气市场的供需现状分析为重点,从天然气资源供给、需求、受周边市场影响程度、市场发展阶段等方面探索中美两国天然气价格水平及走势差异的原因。     

异常高压定容气藏生产特征及开采措施探讨

东海深层气井易发生停喷现象,井筒压力损耗大与流程压力过高均为停喷的重要原因。落实东海异常高压气藏生产特征以及动储量采收率,可为该类型气藏动态分析及后期措施潜力提供依据,此文以X气井为例,分析了异常高压定容气藏的开采特征,并对停喷后现场措施效果进行了分析与探讨。分析结果表明:东海某异常高压定容气藏岩石孔隙膨胀能为开采前期的主要能量来源,占比约70%,地层能量相对常压气藏较为充足,采收率较常规气藏高。当气井无法自喷时,采取放喷或压降等措施来提高采收率,应用效果良好,可为类似气藏开发提供依据。     

Auto-Design of Neural Network–Based GAs for Manipulating the Khangiran Gas Refinery Sweetening Absorption Column Outputs

Abstract

In this work, a new approach for the auto-design of neural network-based genetic algorithm (GA) has been adopted to manipulate the products of an absorption column in the Khangiran gas refinery located in northeastern Iran. The experimental input data included gas flow rate, gas pressure, gas temperature, amine temperature, amine flow rate. In order to construct a GA–artificial neural network (ANN)-based model, the H₂S flow rate and dirty amine flow rate were selected for the output. The proposed method was assessed by the data taken from a case study in the Khangiran gas refinery. Design of topology and parameters of the neural networks as decision variables was first achieved by a trial-and-error procedure followed by genetic algorithms, which enhances the effectiveness of the forecasting scheme. The results reveal that the testing results from the model were in good agreement with the experimental data.