鲁奇FBDB煤气化技术及其最新进展

上世纪30年代,德国鲁奇公司开发出碎煤固定床加压气化技术,应用于煤气化项目,其关键设备为FBDB(固定床干底)气化炉,俗称鲁奇炉.几十年来,先后开发出四代鲁奇炉；同时,为实现气体和废水的达标排放,相继开发出煤气化的尾气处理和废水处理新技术.鲁奇FBDB煤气化技术成熟可靠,在无任何备用的情况下,单台气化炉年运转率超过93％,气化岛年运转率大于98％.由于采用碎煤进料方式,相对气流床干粉或水煤浆进料方式,备煤系统简单,投资及运行费用大为降低,同等规模下,气化岛加上配套空分的投资,约比水煤浆气化低20％.煤种适应范围广,除强黏结性焦煤外,从褐煤到无烟煤均可气化,包括水分、灰分较高的劣质煤；可副产焦油、轻质油及酚等多种高价值产品.新一代Mk+鲁奇气化炉,具有高产低耗、合成气中CH4含量高等特点,且环境友好,可以实现废水的零排放.     

现代煤气化制合成气的工艺

叙述了国内外先进的Texaco气化工艺,Shell气化工艺,GSP气化工艺等3种气流床气化工艺及从气化压力,气化温度及产出合成气组分等方面进行比较的结果,指出,若是煤种适合制浆选择Texaco气化技术性价比较高;Shell气化炉适合用于发电,用于煤化工存在风险;GSP在煤化工领域有很大的发展前景。     

新型撞击流气流床水煤浆气化炉

在对气流床特性及炉内煤气化过程分析的基础上研究开发了具有自主知识产权的新型撞击流气流床水煤浆气化炉。通过优化炉体结构与喷嘴设置强化了热质传递，提出了气化效率，气化炉中试装置的各项技术指标均超过引进技术的技术指标。     

基于旋风渣膜气化炉的潞安烟煤煤气化特性实验研究

气流床气化技术是当前主流的煤气化技术,而已有的气流床气化炉一般采用悬浮气化,气化强度难以继续提高。通过在自主设计的旋风渣膜气化炉实验系统上,对潞安烟煤的旋风渣膜气化特性进行了实验研究,主要研究了运行负荷、蒸汽煤比对气化炉的气化温度、冷煤气效率、碳转化率等气化特性参数的影响规律。实验结果表明:潞安烟煤在旋风渣膜气化炉中具有良好的煤气化效果。     

Second generation gasification combined-cycle power plants for US utilities—Detailed performance and cost estimates

Studies of integrated coal gasification combined-cycle power plants carried out by four US manufactures and process firms are summarised and their results compared on an equivalent basis. The results of these studies indicate that integrated gasification combined-cycle power plants based on the oxygen-blown Texaco entrained flow gasifier and employing current technology gas turbines have the potential for providing substantial performance improvements over conventional coal-fired steam stations with flue gas desulphurisation.     

煤气化联合循环发电工艺评价

介绍了煤气化联合循环发电的工作原理,以及气流床、流化床、固定床三种煤气化工艺的比较,分析了IGCC工艺操作条件对系统效率的影响,及对煤气化联合循环发电工艺的评价。     

煤质对水煤浆气化性能的影响研究

煤质与气流床气化炉的匹配性至关重要,其不但影响气化炉的运行条件,也影响气化性能。本文选择了10种来自新疆和陕西北部的煤样进行了工业分析、元素分析、灰组成分析、灰熔点分析以及成浆性测试,并筛选出适合水煤浆气化的煤样。同时借助Aspen Plus软件对适合水煤浆气化的煤样在相同的煤浆浓度、碳转化率及操作压力条件下开展煤质对水煤浆气化性能影响的模拟分析。结果表明煤中灰含量越高,冷煤气效率和有效气含量越低,比氧耗和比煤耗越高;煤中O/C质量比和H/C质量比的增加也会导致冷煤气效率和有效气含量降低,比氧耗和比煤耗增加。因此从水煤浆气化经济性考虑,建议水煤浆气化煤质灰含量小于9.0wt%,煤中O/C质量比小于0.173,H/C质量比小于0.065。     

Texaco气化炉混合过程及化学反应过程中的控制因素分析

气流床煤气化炉内的湍流流动和反应过程存在强烈耦合作用,为确定气化炉不同区域中起主导作用的控制因素,通过对Texaco气化炉进行三维数值模拟以及对计算结果进行分析,详细列出了气化炉中与流动、反应相关的主要长度尺度和时间尺度.通过对这些特征尺度进行比较,发现在火焰区不能忽略因气体组分脉动而对焦炭异相反应产生的影响;在非火焰区,尽管慢反应控制气相反应过程,但总体来说,同相反应的时间尺度远小于宏观混合过程的时间尺度,这说明采用快反应假定对气化炉内的化学机理进行简化能够合理预测气化炉的运行特性.     

煤焦气化反应动力学研究

气流床气化技术是煤炭清洁、高效转化的重要途径和发展方向之一。利用热天平,采用等温热重法对抽样选出的煤种在800℃～1 400℃温度范围内进行了煤焦CO2气化反应动力学特性研究。研究结果表明:高温下煤焦的气化反应特性不同于低温时的反应特性,在900℃～1 000℃时气化反应逐步由化学反应控制过渡到过渡区控制,在1 100℃～1 300℃时气化从反应过渡区控制逐步到扩散区控制;不同粒径的煤粉气化反应,在相同的时间内,1 000℃时的碳转化率、气化反应速率比950℃时的碳转化率、气化反应速率高很多,950℃时的碳转化率、气化反应速率比900℃时的碳转化率、气化反应速率高。     

An Eulerian model for the simulation of an entrained flow coal gasifier

A numerical model is used to simulate the gasification of coal inside an entrained flow gasifier. The model is based on the Eulerian–Eulerian concept. Both gas and particulate phases conservation Eulerian equations are solved. The model used includes the coal particle processes, such as drying, volatilization, heterogeneous reactions of combustion and gasification, particle drag and turbulent dispersion, as well as heat-up.The model is applied to the investigation of the gasification of coal in a commercial entrained flow gasifier, from which experimental data is available. The results obtained show good agreement for both the main and minor species, and temperature.     

气化炉中生物质——煤共同气化的模拟研究

在气化炉内采用煤粉和生物质共气化可解决生物质不易稳定流化和生成焦油两大难题,采用流程模拟软件PROⅡ对炉内的气化过程进行了模拟计算,得到了汽氧比和氧碳比和生物质／煤比对气化过程的影响。气化炉内优化的反应条件为：反应温度1350℃,[H2O]／[O2]=0．32,[O][C]=1．05,气化得到的合成气的高位热值Qgr=7150kJ／Nm3,有效气产率为1．59Nm3／kg。     

Towards the improvement of thermal efficiency in lignite‐fired power generation: Concerning the utilization of Polish lignite deposits in state‐of‐the‐art IGCC technology

Integrated coal Gasification Combined Cycle (IGCC) is the most advanced technology for coal‐fired power generation. The two‐stage entrained flow gasification process allows for the use of a wide range of coal, as long as the gasification temperature is above the ash melting point of a used fuel. In this gasification technology, lignite, which often has a low ash melting point, can be preferably utilized. However, ash fluidity is also another importance, because the behaviour of molten slag can diminish a stable ash discharge from a gasifier. As the eligibility of coal ash properties is a considerable factor, water physically and chemically kept in lignite (30 – 60% in mass) attributes to deteriorating gasification efficiency, because it causes significant heat loss and increasing oxygen consumption. Developing a thermal evaporative lignite drying method will be a necessary attempt to apply lignite to the coal gasification process. For those preceded objectives, coal and ash properties and drying characteristics of several grades of Polish lignite, extracted from Belchatow and Turow deposits, have been experimentally investigated in a preliminary study evaluating the applicability and consideration for its utilization in state‐of‐the‐art clean coal technology, IGCC. This paper particularly discusses the eligibility of Polish lignite from the perspective of the fusibility and fluidity of ash melts and the fundamental drying kinetics of lignite in superheated steam in the light of water removal. The viscosity of ash melts is measured at high temperature up to 1700 °C. In the drying tests, the significant influence of structural issues, because of the provenance and origin of lignite on the drying characteristics, was found by applying the method of sensitivity analysis of physical propensity. This paper concludes that the investigated Polish lignite has characteristics favourable for utilization in IGCC technology, once the precautions related to its high moisture have been carefully addressed. Copyright © 2016 John Wiley & Sons, Ltd.     

Gasification of a pulverized sub-bituminous coal in CO2 at atmospheric pressure in an entrained flow reactor

Char gasification by CO₂ may play an important role in oxy-fuel applications and affect particle temperature histories and overall reaction rates during combustion. This paper presents the results of a complete set of experiments of char gasification in CO₂ performed with a pulverized Indonesian sub-bituminous coal in an entrained flow reactor under realistic conditions; series of burnout curves at different reactor temperatures (1040–1300 °C) and CO₂ concentrations (0.7–100%) reveal consistent trends in the gasification rates. The study included also devolatilization and oxidation tests with this coal in the same experimental facility. The data are used to derive apparent kinetics for the three processes, in a manner similar to that followed in a previous work for the oxidation of a pulverized coal. The gasification kinetic parameters and reaction rates measured are then compared with values taken or derived from previous works by others, obtained by thermogravimetric analysis or experiments in entrained flow reactors. Finally, the relevance of char gasification in the overall reaction rate under conditions representative of those in an industrial boiler is explored, in particular for the case of oxy-coal combustion.     

煤制天然气产业发展前景分析

我国天然气供不应求的局面将长期存在,而利用煤炭资源相对丰富的特点发展煤制天然气产业,是缓解我国天然气供求矛盾的一条有效途径。煤制天然气产品的低热值比国家天然气质量标准规定的低热值高17.8%～21%,能量转化效率高。当石油价格为80美元/bbl时,与进口天然气、进口LNG相比,煤制天然气价格具有竞争力。固定床鲁奇炉加压气化技术是煤制天然气较好的选择,而耐硫变换、低温甲醇洗、硫回收、丙烯制冷、压缩干燥等工艺单元不存在技术问题。如果我国企业开发的低温甲烷化技术获得成功,那么煤制天然气项目就可以完全实现国产化,使我国煤制天然气技术居于世界前列。利用低品质的褐煤、采用碎煤固定床鲁奇炉加压气化技术,粗煤气中含有8%～12%的甲烷,气化单元投资仅为气流床气化技术的一半,电耗低,同时可实现焦油、轻油、酚、硫磺、硫酸铵等多联产。但对于排出的"黑水"问题,应采取积极措施尽快予以解决。煤制天然气项目最好在示范装置取得圆满成果之后,特别是环境保护问题解决之后,再进行项目的研究和建设。厂址最好设在坑口或煤炭产地附近,并且要考虑输送问题。     

煤的气化技术及其应用

煤气化技术是环境友好的现代煤化丁的关键技术。介绍了当今世界主要的煤气化技术,着重介绍了已工业化生产的鲁奇、Transport、壳牌、德士古、康菲气化炉及我国自主开发的华东理工大学气化炉等技术,并且介绍了煤气化技术在煤气化联合循环发电和在煤化丁的合成油、合成氨、合成甲醇、合成烯烃等方面的应用。重点介绍了我国煤化工发展的具体情况。     

Gasification of preheated coal: Experiment and thermodynamic equilibrium calculation

A new process integrating a circulating fluidized bed (CFB) reactor and an entrained bed reactor was proposed for gasification of preheated coal. The CFB reactor as a preheater was successfully used in clean coal combustion. In this study, gasification of preheated coal was tested in a bench-scale test rig, which consisted of a CFB preheater and a down flow bed (DFB) gasifier. The effects of operating parameters of the preheater and gasifier were revealed via thermodynamic equilibrium calculations. A stable preheating process was obtained in the CFB preheater at the O₂/C molar ratio of 0.31 and higher gasification reactivity was gained in preheated char owing to the improvement in intrinsic reactivity, specific surface area and total pore volume. Effective gasification of preheated char was achieved in the DFB gasifier at 1100 °C and the total O₂/C molar ratio of 0.67, meanwhile the CO + H₂ yield and carbon conversion increased. Thermodynamic equilibrium calculations revealed when the gasification reaction rates varied little above 1100 °C and the same carbon conversion was achieve in gasifier, lowering the temperature would lead to an increase in cold gas efficiency and a decrease in O₂ demand.     

Production of hydrogen-rich syngas from novel processes for gasification of petroleum cokes and coals

This paper investigates the effects of various gasification parameters on the composition of the syngas produced from the co-gasification of petcoke and coal for improved applications. Two types of coal and one type of petcoke are considered to form four different mixtures for study in order to analyze the system operating conditions and assess the system performance. The gasifier is modeled and simulated in Aspen Plus based on Gibbs free energy minimization approach of an entrained flow gasifier with oxygen being the gasification oxidant generated by a cryogenic air separation unit. The energy efficiency assessment of the four feed mixture shows that the maximum energy efficiency of the gasification is improved for higher grade coals when co-gasifying them with petcoke in contrast to the lower grade coal. The four mixtures require higher steam and lower oxygen to achieve the maximum energy efficiency compared to the gasification of coal only, which appears to be true for mixtures of both considered coal types.     

Coal gasification development and commercialization of the texaco coal gasification process

The development of the Texaco coal gasification process utilizing an entrained bed downflow slagging gasifier is discussed. the advantages of the process including its simplicity and lack of formation of environmentally unacceptable and undesirable by-products are emphasized. Treatment of the crude gasification product gas to produce a clean gas for use as fuel or as feed stock for chemical manufacture is also covered. Status of the commercialization of the process is included.     

Numerical Simulation of Pressure Effects on the Gasification of Australian and Indian Coals in a Tubular Gasifier

This article presents a numerical study on the effect of pressure on the gasification performance of an entrained flow tubular gasifier for Australian and Indian coals. Gasification using a substoichiometric amount of air, with or without steam addition, is considered. The model takes into account phenomena such as devolatilization, combustion of volatiles, char combustion, and gasification. Continuous-phase conservation equations are solved in an Eulerian frame and those of the particle phase are solved in a Lagrangian frame, with coupling between the two phases carried out through interactive source terms. The numerical results obtained show that the gasification performance increases for both types of coal when the pressure is increased. Locations of devolatilization, combustion, and gasification zones inside the gasifier are analyzed using the temperature plots, devolatilization plots, and mass depletion histories of coal particles. With increase in pressure, the temperature inside the gasifier increases and also the position of maximum temperature shifts upstream. For the high-ash Indian coal, the combustion of volatiles and char and the gasification process are relatively slower than those for the low-ash Australian coal. The mole fractions of CO and H₂ are found to increase with increase in pressure, in all the cases considered. Further, the effects of pressure on overall gasification performance parameters such as carbon conversion, product gas heating value, and cold gas efficiency are also discussed for both types of coals.