Performance of a coal gasification pilot plant with hot fuel gas desulfurization

A coal gasification pilot plant operation with hot fuel gas desulfurization (HGD) was performed taking two coals (Indonesian ABK and MSJ) that differ in their carbon and sulfur contents. A dry-feeding entrained-bed type gasifier was used for gasification with oxygen and capable of operating at 30 bar pressure and 1,550 °C. The HGD unit consisted of a transport desulfurizer, a bubbling regenerator and a multi-cyclone. Attention was focused on attaining high carbon conversion and cold gas efficiency in the entrained bed reactor and the sulfur removal efficiency of the hot fuel gas desulfurization unit. The optimum conditions for achieving high performance of the operation are reported.     

Φ3.6m两段炉煤气站模拟设计

根据设计依据中原料煤和所需煤气参数,经过计算和对气化、净化以及脱硫工艺的分析,确定采用5台Φ3.6 m两段炉为气源,经除尘、除焦油、脱硫得到净化煤气后,送往用气点。核算分析表明,煤气站气化炉选型合理,工艺路线确定合适,净化煤气等参数满足用气点要求,模拟设计达到设计要求。     

发生炉煤气中的NH3及其对煤气站系统的影响

发生炉煤气中NH3的形成过程较为复杂,煤的热解温度、气化温度、气化煤中氮的含量、煤化程度及惰质组含量的高低等因素直接影响煤气发生炉中NH3的生成。就NH3的含量而言,一段炉煤气要大于两段炉和干馏炉煤气。同时分析并指出煤气中的NH3与CO2和煤气冲洗水反应生成NH4HCO3,NH4HCO3的存在给酚水浓缩蒸发系统带来一定的安全隐患,需要采取有效措施,从源头杜绝其危害及安全隐患;发生炉煤气中的NH3在煤气湿法脱硫中可以部分或全部替代纯碱作为脱硫吸收剂,从而节约脱硫成本。     

Numerical simulation of coal gasification in entrained flow coal gasifier

This paper presents modeling of a coal gasification reaction, and prediction of gasification performance for an entrained flow coal gasifier. The purposes of this study are to develop an evaluation technique for design and performance optimization of coal gasifiers using a numerical simulation technique, and to confirm the validity of the model. The coal gasification model suggested in this paper is composed of a pyrolysis model, char gasification model, and gas phase reaction model. A numerical simulation with the coal gasification model is performed on the CRIEPI 2 tons/day (T/D) research scale coal gasifier. Influence of the air ratio on gasification performance, such as a per pass carbon conversion efficiency, amount of product char, a heating value of the product gas, and cold gas efficiency is presented with regard to the 2 T/D gasifier. Gas temperature distribution and product gas composition are also presented. A comparison between the calculation and experimental data shows that most features of the gasification performance were identified accurately by the numerical simulation, confirming the validity of the current model.     

Desulfurization matching with coal poly-generation system based on dual gas resources

The coal poly-generation system for the production of alcohol and ether fuels as well as power is one of advanced coal utilization techniques. The team leaded by Professor Xie Kechang is carrying out the research on the poly-generation system to produce the syngas from the combination of gasified and pyrolyzed coal gas (dual gas resources) for the alcohol ether synthesis. Gas desulfurization is one of the key technologies for this system. The desulfurization matching with dual gas resources based poly-generation system for the production of alcohol and ether fuels as well as power is presented according to gas components, sulfur content, sulfur species and desulfurization accuracy in this technology. This matching desulfurization is classified into hot gas desulfurization, normal gas desulfurization, warm gas desulfurization and organic sulfur catalytic conversion. The preparation of H₂S removal sorbents, organic sulfur hydrolysis catalyst and the evaluation of their activities involved in the system were investigated. The H₂S removal efficiencies of the crude and fine desulfurization sorbents prepared for hot gas desulfurization are 90% and 99% at 500 °C in simulating coal gas, and their sulfur capacities are 21.85 wt.% and 24.91 wt.%, respectively. The organic sulfur catalyst shows the high hydrolysis activity, and the hydrolysis conversion of COS is more than that of CS₂ on the same catalyst. The research will provide necessary information for the matching desulfurization technology in the demonstration project on dual gas resources coal poly-generation system.     

干煤粉加压气化技术的现状和进展

干法进料的气流床煤气化技术是当今国际上最先进的煤气化技术之一,与水煤浆气化技术相比,具有煤种适应性广、原料消耗低、碳转化率高、冷煤气效率高等优势,有更强的市场竞争力。为了加强对干煤粉加压气化技术的基础研究和应用推广,研究了干煤粉气化炉、气流输送过程、合成气净化系统及其配套工艺,分析了干煤粉气化炉在应用中存在的问题,并针对这些问题提出了解决的思路。概述了国内外大型粉煤气流床气化技术发展的主要情况,分析了干法进料气流床煤气化技术中存在的问题与采取的技术途径。     

Shell气化炉的结构特点及操作维修

详细介绍了Shell气化炉的主要组成(按工艺功能分):气化反应段、急冷段、输气管段、气体返回段、气体冷却段、辅助设备等,总结了气化炉的结构特点:结构复杂、控制点多、操作难度大、制粉系统故障率高等,并对气化炉的安装、操作维修进行了说明,以期对引进技术的消化吸收工作起指导作用。     

The comparison study on the operating condition of gasification power plant with various feedstocks

Gasification technology, which converts fossil fuels into either combustible gas or synthesis gas (syngas) for subsequent utilization, offers the potential of both clean power and chemicals. Especially, IGCC is recognized as next power generation technology which can replace conventional coal power plants in the near future. It produces not only power but also chemical energy sources such as H₂, DME and other chemicals with simultaneous reduction of CO₂. This study is focused on the determination of operating conditions for a 300 MW scale IGCC plant with various feedstocks through ASPEN plus simulator. The input materials of gasification are chosen as 4 representative cases of pulverized dry coal (Illinois#6), coal water slurry, bunker-C and naphtha. The gasifier model reflects on the reactivity among the components of syngas in the gasification process through the comparison of syngas composition from a real gasifier. For evaluating the performance of a gasification plant from developed models, simulation results were compared with a real commercial plant through approximation of relative error between real operating data and simulation results. The results were then checked for operating characteristics of each unit process such as gasification, ash removal, acid gas (CO₂, H₂S) removal and power islands. To evaluate the performance of the developed model, evaluated parameters are chosen as cold gas efficiency and carbon conversion for the gasifier, power output and efficiency of combined cycle. According to simulation results, pulverized dry coal which has 40.93% of plant net efficiency has relatively superiority over the other cases such as 33.45% of coal water slurry, 35.43% of bunker-C and 30.81% of naphtha for generating power in the range of equivalent 300 MW.     

对置式四喷嘴气化炉生产甲醇工艺

对兖矿国泰化工有限公司煤处理能力1 000 t/d的对置式四喷嘴新型气化炉及配套工程进行了详细介绍,分析了甲醇合成工艺的经济效益。该工艺采用新型对置式四喷嘴气化炉加压气化、部分气量通过部分冷凝变换、聚乙二醇二甲醚脱硫、三塔精馏等,能显著提高生产能力,缩短流程,节省投资,简化操作,已成功用于甲醇的生产,取得很好的经济效益。     

低热稳定性低阶煤在碎煤加压气化工艺中的应用

为提高低热稳定性低阶煤的碎煤加压气化效果,采用新疆、河南等地碎煤加压气化工艺,研究低阶煤热稳定性对碎煤加压气化效果的影响。结果表明:低热稳定性低阶煤的单台气化炉氧负荷仅达到设计的70%左右,比高热稳定性低阶煤低40%。煤的热稳定性越低,粗煤气中煤粉含量越高,影响煤气水分离、变换等后续工艺。最后提出可通过研究不同粒度煤的热稳定性、确定最小入炉煤粒度、测定碎煤加压气化煤粉的粒度、改进碎煤加压气化除尘系统、选择合理的气化压力、采用气化工艺组合等提高低热稳定性低阶煤碎煤加压气化效果。     

Experiment and mathematical modeling of a bench-scale circulating fluidized bed gasifier

The gasification of two different coals and chars with CO₂ and CO₂/O₂ mixture in a 48-mm-i.d. circulating fluidized bed (CFB) gasifier is investigated. The effects of operation condition on gas composition, carbon conversion and gasification efficiency were studied. A simple CFB coal gasification district mathematical model has been set up. The effects of coal type and CFB operating conditions on CFB coal gasification are discussed based on the CFB gasification test and model simulation. The main operation parameters in CFB gasification system are coal type, gas superficial velocity, circulating rate of solids and reaction temperature. It is found that CO concentration and carbon conversion increase with increasing solids circulating rate and decreasing gas velocity due to the increase in gas residence time and solids holdup in the CFB. The carbon conversion increases with increasing temperature and O₂ concentration in the inlet gas. The experimental results prove that the CFB gasifier works well for high volatile, high reactivity coal.     

Operation characteristics of 1 ton/day-scale coal gasifier with additional stage

A one-stage coal gasifier was modified to accommodate the two stages of coal feeding. Operating characteristics were compared between the one-stage and two-stage gasification in terms of syngas composition, carbon conversion, shape and inner structure of produced slags, characteristics of particle size distribution in entrained fines, and effects on particulate removal facilities. Temperature at the second stage of the gasifier resulted in lower values, which confirms the performance of the second stage as a reduction area by endothermic reactions. The results suggest that the 10–20% increase in coal feeding to the second stage might not cause much loss in carbon conversion. Produced slag and the performance of metal filters and water scrubber were similar with the earlier results from one-stage gasification tests. The two-stage gasification appears to help in increasing the cold gas efficiency for the certain operating range. Two-stage gasification had an impact on the 0.1–1 μm size of entrained fines, which appear to be cenospheres that occur during the rapid quenching in temperature.     

煤气化工艺的发展趋势之一：—两段气化法

如果仔细观察近年来国外开发的和正在开发的各种煤气化工艺,不难发现采用两段气化工艺的愈来愈多,这种气化方法既保持了气流床气化的碳效率高、生产能力大的特点,又吸取了逆流气化的优点,将高温煤气显热用于煤气化反应,使煤气出口温度下降,煤气夹带的熔融液渣固化,因此使气流床气化工艺更趋完善。     

煤气化技术的发展与应用

综述了煤气化技术的现状及发展趋势,对煤气化技术的原理进行了阐述,概括介绍了固定床、流化床和气流床三种不同煤气化技术的特点,并对鲁奇炉、德士古炉、壳牌炉、恩德炉等几种常用气化炉的性能做了比较,重点介绍了恩德粉煤气化炉的发展历史、特点及应用现状,认为恩德粉煤气化技术具有自己独特的优势,是国内实力比较薄弱的合成氨企业进行技术改造的适宜技术.     

Effects of operating factors in the coal gasification reaction

The effects of operating factors on a gasification system were reviewed by comparing a computational simulation and real operation results. Notable operation conditions include a conveying gas/coal ratio of 0.44, an oxygen/coal ratio of 0.715, a reaction temperature of 1,000 °C, and reaction pressure of 5bar in the case of Adaro coal; based on this, the cold gas efficiency was estimated as 82.19%. At the point of the reaction temperature effect, because the cold gas efficiencies are more than 80% when the reaction temperatures are higher than 900 °C, the gasifier inner temperature must remain over 900 °C. At high reaction temperature such as 1,400 °C, the reaction pressure shows little effect on the cold gas efficiency. The addition of steam into the gasifier causes an endothermic reaction, and then lowers the gasifier outlet temperature. This is regarded as a positive effect that can reduce the capacity of the syngas cooler located immediately after the gasifier. The most significant factor influencing the cold gas efficiency and the gasifier outlet temperature is the O₂/coal ratio. As the O₂/coal ratio is lower, the cold gas efficiency is improved, as long as the gasifier inner temperature remains over 1,000 °C. With respect to the calorific value (based on the lower heating value, LHV) of produced gas per unit volume, as the N₂/coal ratio is increased, the calorific value per syngas unit volume is lowered. Decreasing the amount of nitrogen for transporting coal is thus a useful route to obtain higher calorific syngas. This phenomenon was also confirmed by the operation results.     

加压流化床煤气化炉衬里材料的选择与烘制

加压流化床煤气化技术是近年来随着洁净煤技术的兴起而发展起来的新一代大型、先进煤气化技术。就加压流化床煤气化炉耐火衬里的特殊要求进行了耐火材料的选型,并根据所选耐火材料特性制定了烘炉工作曲线,并比较了烘炉所需实际燃料气量和估算值,结果表明计算值与实际值吻合较好,并为大型流化床反应器的烘炉工艺制定和实施提供一种理论参考和估算方法。     

干法进料加压粉煤气化制合成气

干法进料加压粉煤气化工艺具有氧耗低、煤种适应广、冷煤气效率高等优点，国内宜先从中间试验起步进行工艺和工程开发。在气化炉结构方面，立式炉（与ＧＳＰ炉相似）结构简单，国内工作基础较好，宜作为干粉气化的基本炉型。     

烟煤水煤气气化炉运行的可行性分析

烟煤水煤气气化炉是将双火层煤气发生炉的气化原理用于水煤气气化的一种炉型。介绍了双火层气化炉的炉型规格、供气形式和半水煤气组成;从煤气中CO2和CH4含量、气化炉反应温度、蒸汽量的调整等方面分析了烟煤水煤气气化炉生产运行的可行性;介绍了烟煤水煤气气化炉的结构形式和工艺流程;计算了原料煤成本的经济效益,结果表明,4万t/a合成氨装置每年可节约原料煤费用1160万元,20万t/a甲醇装置每年可节约原料煤费用6960万元。     

型煤富氧气化运行总结

介绍福建本地型煤的特点及型煤间歇气化存在的问题。通过富氧气化攻关,证明福建本地型煤采用富氧气化比间歇气化更具优势,富氧气化可有效解决劣质煤的气化问题。经实际运行证实:富氧气化本地型煤具有炉况相对稳定、产气量大、煤耗低、炉渣残碳含量低等优点,但也存在炉上温度高、煤气中CO2含量高等问题,有待进一步解决。     

The feasibility of a coal gasifier combined with a high-temperature fuel cell

The purpose of the study presented in this paper was to find out the feasibility of integrating a 50 MW fuel cell system, fed by gas from a coal gasifier, with an existing network for distribution of heat and power. The work presented is the results of the technical evaluation of a 50 MW coal fired high-temperature fuel cell power plant. The overall system can be divided into four subsystems including: coal gasification, gas cleaning, power generation and heat recovery.

The final system, a entrained flow gasifier combined with standard low-temperature gas cleanup and SOFC, resulted in an overall electrical efficiency of about 47%, and an overall efficiency close to 85%.