气化参数对IGCC系统中气化炉性能的影响

首先单独对气化炉出口合成气成分含量进行核算,计算结果与文献基本吻合.然后建立200 MW级整体煤气化联合循环(IGCC)系统模型,对基本参数下的IGCC系统进行计算,得出整个系统的性能参数.最后对不同气化参数温度、水煤浆浓度、氧气浓度、O/C比的气化炉性能及其整个IGCC系统效率进行比较,分析不同气化条件下的合成气成分体积含量、冷煤气效率、有效气(CO+H2)体积含量、比氧耗、比煤耗及整个IGCC系统效率的变化.结果表明:提高水煤浆的浓度,有利于提高气化炉的冷煤气效率;气化温度对IGCC系统性能影响较大;提高氧气浓度有利于提高气化冷气效率和系统的效率,本系统对应的最佳O/C比为1.02左右.     

Texac0煤气化炉数学模型研究(2) --计算结果及分析

利用论文第一部分建立的能够反映Texaco气化炉内部质量和能量平衡、并考虑了多种化学反应动力学的数学模型,详细计算了气化炉的主要运行参数(如水煤浆质量配比,氧气纯度,氧煤比,煤粉粒径,气化温度以及气化压力等)对气化炉性能的影响.在展现各种参数对最终气化产物成分的影响的同时,分析和揭示了这些影响的内在机理和规律.分析结果表明:气化温度是影响气化反应速度和最终产物成分的最关键因素.表7参2     

Texac0煤气化炉数学模型研究——计算结果及分析

利用论文第一部分(见《动力工程》2001年No.2期)建立的能够反映Texaco气化炉内部质量和能量平衡,并考虑了多种化学反应动力学的数学模型,详细计算了气化炉的主要运行参数(如水煤浆质量配比、氧气纯度、氧煤比、煤粉粒径、气化温度以及气化压力等)对气化炉性能的影响.在展现各种参数对最终气化产物成分的影响的同时,分析和揭示了这些影响的内在机理和规律.分析结果表明:气化温度是影响气化反应速度和最终产物成分的关键因素.表7.     

石油焦水煤浆在新型气化炉内气化过程的数值计算

对石油焦水煤浆(PCCWS)在多喷嘴新型水煤浆气化炉内的气化过程进行了数值计算,考察了气化炉内的温度分布、各种气化产物浓度分布规律.结果表明:同浓度的石油焦水煤浆气化与普通水煤浆气化相比,气化炉内平均温度略有上升,碳转化率提高,气化炉出口粗煤气中有效气(CO H2)含量提高7.91%,CO2和H2O浓度大幅下降,水分解率大大提高;石油焦水煤浆气化可以节约氧气约6%,气化效果明显优于普通水煤浆.     

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煤气化炉数学模型研究（2）—计算结果及分析

利用论文第一部分建立的能够反映Texaco气化炉内部质量和能量平衡,并考虑了多种化学反应动力学的数学模型,详细计算了气化炉的主要运动参数（如水煤浆质量配比,氧气纯度,氧煤比,煤粉粒径,气化温度以及气化压力等）对气化炉性能的影响,在展现各种参数对最终气化产物成分的影响的同时,分析了揭示了这些影响的内在机理和规律,分析结果表明：气化工是影响气化反应速度和最终产物成分的最关键因素,表7参2。     

水煤浆气化合成气显热回收对IGCC电站性能的影响

利用Thermoflex热力系统软件分别建立了基于GE-Texaco和E-Gas水煤浆气化的400MW级IGCC电站模型,通过设置的5种合成气显热回收方案,分析了水煤浆气化炉型、废热锅炉配置和废热锅炉出口合成气温度3个因素对IGCC电站性能的影响.结果表明:与GE-Texaco全热回收气化技术相比,采用E-Gas全热回收气化技术时蒸汽轮机的发电量和净发电量较低,供电效率提高、厂用电耗率降低;与合成气激冷方案相比,增设辐射废锅和对流废锅可以提高GE-Texaco气化合成气显热回收过程的蒸汽质量流量,进而提高IGCC电站的蒸汽轮机发电量、净发电量和供电效率;降低废热锅炉出口合成气的温度可以改善IGCC电站的整体性能.     

气流床煤气化装置稳态模拟及优化分析

煤气化过程是煤中有机质在一定温度、压力及气化剂(如蒸汽、空气或氧气等)等条件下发生一系列复杂化学反应,将固体煤转化成粗合成气,同时副产蒸汽、焦油、灰渣等产品的过程。以工业化运行气流床粉煤气化及水煤浆气化装置为研究对象,采用Aspen Plus流程模拟软件,建立与实际工况吻合的气化装置稳态模拟模型。通过使用该模型,研究了氧煤比、加入烧嘴水蒸气量、煤浆浓度、激冷水量、气化压力等工艺参数对煤气化反应性能的影响,结果表明:水煤浆气化有效气含量随氧煤比降低先增加后减少,随煤浆浓度增加而增加;粉煤气化有效气含量随氧煤比降低而增加,H2含量随蒸汽量增加而增加;气化压力对煤气化合成气组成影响较小;降低激冷水量有利于提高合成气水汽比及变换装置副产蒸汽量,并可降低激冷水泵和洗涤塔低压灰水泵功率。运用稳态模拟模型指导生产装置操作优化,每年可实现经济效益507.51万元。     

大型海藻生物质气化的建模与计算

采用Aspen Plus流程模拟软件对以条浒苔为代表的大型海藻的气化进行数值模拟.研究了海藻气化炉的重要相关参数(即条浒苔含水量、氧气条浒苔比、气化温度、氧气浓度)对气化结果的影响.结果显示:随着条浒苔含水量的增加,合成气的有效成分(H2+CO)总含量减少;当氧气条浒苔比为0.56时,气化温度增大到800℃,合成气中(H2 +CO)的摩尔比例达到最大值;氧气的纯度提高,有利于合成气中有效成分的增加.     

焦油对生物质气化再燃还原NO的影响

采用配制含焦油模型化合物的生物质气的方法,实验研究了焦油的加入对生物质气化再燃还原NO的影响.模拟的生物质气化气由H2、CH4、CO、CO2、N2构成,并选择了苯、甲苯、苯酚和苯乙烯作为焦油模型化合物.实验在电加热的刚玉管流反应器中进行,实验温度在900～1,400,℃之间.研究了反应器入口焦油含量、氧气浓度、NO初始浓度、反应停留时间及反应温度等因素对还原NO的影响,分析了含焦油的生物质气化再燃特性.证实了焦油有助于提高生物质气化气还原NO的效率;含焦油的生物质气化再燃的最佳当量比在1.20～1.65之间,并且随着NO初始浓度的增加及停留时间的延长,NO还原效率逐渐增加;高温下,焦油含量较高时,有炭黑生成.     

生物质化学链气化联合燃气轮机发电系统模拟

使用Aspen Plus软件对以Fe_2O_3为载氧体的生物质化学链气化系统进行模拟,分析温度、压力、载氧体与生物质摩尔比、水蒸气与生物质摩尔比等因素对合成气制备的影响;对不同生物质的气化条件进行优化;将气化制得的合成气通入M701F燃气轮机中发电,考察系统的发电效率。结果表明:常压下,不同生物质气化的优化温度均在740℃左右,此时制备的合成气冷煤气效率较高;提高反应压力有利于系统热量自平衡,但合成气的冷煤气效率降低;载氧体与生物质摩尔比的优化值与生物质中氧碳摩尔比呈负相关,且达到优化值时,气化环境中氧碳摩尔比在1.25左右;水蒸气通入气化系统后冷煤气效率可提高15.00%～20.00%,主要原因为H_2的产量显著增加,通入水蒸气后的气化环境的氧碳比在1.4左右时,制备合成气的冷煤气效率较高;系统的发电效率在30.00%～37.00%,高于生物质发电效率。     

燃气轮机调节方式对IGCC系统变工况性能的影响

为选择合理的燃气轮机调节方式,采用Thermoflex软件建立了200 MW级IGCC系统模型,从系统的角度出发比较研究了燃气轮机的调节方式对燃气顶循环系统、蒸汽底循环系统和整个IGCC系统变工况性能的影响.研究表明:与压气机可转导叶(IGV)不调相比,IGV可调时更有利于提高系统的变工况性能.等燃气透平初温(T3)调...     

Simulation of a new biomass integrated gasification combined cycle (BIGCC) power generation system using Aspen Plus: Performance analysis and energetic assessment

A new biomass integrated gasification combined cycle (BIGCC), which featured an innovative two-stage enriched air gasification system coupling a fluidized bed with a swirl-melting furnace, was proposed and built for clean and efficient biomass utilization. The performance of biomass gasification and power generation under various operating conditions was assessed using a comprehensive Aspen Plus model for system optimization. The model was validated by pilot-scale experimental data and gas turbine regulations, showing good agreement. Parameters including oxygen percentage of enriched air (OP), gasification temperature, excess air ratio and compressor pressure ratio were studied for BIGCC optimization. Results showed that increase OP could effectively improve syngas quality and two-stage gasification efficiency, enhancing the gas turbine inlet and outlet temperature. The maximum BIGCC fuel utilization efficiency could be obtained at OP of 40%. Increasing gasification temperature showed a negative effect on the two-stage gasification performance. For efficient BIGCC operation, the excess air ratio should be below 3.5 to maintain a designed gas turbine inlet temperature. Modest increase of compressor pressure ratio favored the power generation. Finally, the BIGCC energy analysis further proved the rationality of system design and sufficient utilization of biomass energy.     

Process simulation and integration of IGCC systems with novel mixed ionic and electronic conducting membrane-based water gas shift membrane reactors for CO2 capture

A mixed ionic and electronic conducting (MIEC) membrane provides an alternative to the palladium alloy membrane for water gas shift membrane reactor. It exhibits much better sulfur resistance performance than the palladium alloy membrane. In this paper, the thermodynamic performance of the integrated gasification combined cycle (IGCC) system with MIEC membrane reactor is predicted for the first time. The effects of reactor operation parameters on system flowsheet and performance are investigated and illustrated by sensitive analysis. When the reactor operation temperature is 900 °C and the H₂O decomposition ratio is 0.5, the system net efficiency is about 38.90%, which is 2.6% points higher than that of the IGCC with Selexol. The system net efficiency increases with the decrease of operation temperature. With the net efficiency of the conventional system as the reference, the minimum H₂O decomposition ratios at different operating temperatures are provided.     

Performance analysis of a syngas-fed gas turbine considering the operating limitations of its components

As the need for clean coal technology grows, research and development efforts for integrated gasification combined cycle (IGCC) plants have increased worldwide. An IGCC plant couples a gas turbine with a gasification block. Various technical issues exist in designing the entire system. Among these issues, the matching between the gas turbine and the air separation unit is especially important. In particular, the operating condition of a gas turbine in an IGCC plant may be very different from that of its original design. In this study, we analyzed the impact of the use of syngas on operating conditions of the gas turbine in an IGCC plant. We evaluated the performance of a gas turbine under operating limitations in terms of compressor surge and turbine metal temperature. Although a lower degree of integration may theoretically allow higher gas turbine power output and efficiency, it causes a reduction in compressor surge margin and overheating of the turbine metal. The turbine overheating problem may be solved using several methods, such as a reduction in the firing temperature or an increase in the turbine cooling air. The latter yields a much smaller performance penalty. To achieve an acceptable margin for the compressor surge, either further reduction in the firing temperature or further increase in the coolant is required. Ventilation of some of the nitrogen generated by the air separation unit, i.e., a reduction of the nitrogen supply to the combustor, is another option. Coolant modulation yields the lowest performance penalty. Reduction of the nitrogen supply provides much greater system power output than control of the firing temperature. For nitrogen flow and firing temperature controls, there are optimal levels of integration degrees in terms of net system power output and efficiency.     

换热器压降对ORC发电系统的影响

在考虑换热器压降及散热损失的情况下建立中低温地热驱动的有机朗肯循环(ORC)发电系统模型并通过500 kW示范工程进行验证。模型选取5种有机工质,研究换热器压降在不同热源温度、蒸发温度和冷凝温度下对系统性能的影响。研究结果表明随着热源温度以及蒸发温度的升高,压降对系统净发电量以及净发电效率的影响逐渐降低,但随着冷凝温度的升高,压降对系统净发电量的影响逐渐升高。其中,采用R227ea的系统受换热器压降影响最小,采用R123的系统受影响最大。     

整体煤气化联合循环系统中采用独立或整体化空气分离装置的探讨

目前采用氧气气化技术的整体煤气化联合循环(IGCC)系统对空气分离装置的配置主要有独立(低压)空气分离装置和整体化(中压)空气分离装置.从基本的热力学过程入手,研究对比了独立和整体化空气分离装置的优劣.结果表明:在一定压比范围内,整体化空气分离装置在各方面都劣于独立空气分离装置,同时也不会带来IGCC系统效率的提高.     

生物质费托合成制取液体燃料的仿真及分析

以生物质费托合成制取液体燃料工艺为基础,利用Aspen Plus软件建立其流程的仿真模型,研究各单元操作参数变化对航空煤油产量的影响,并在最优工况下对系统进行能量分析.结果表明:生物质气化单元对航油产量的影响主要来自产物合成气中H2与CO物质的量之比(H2/CO),最优操作条件为T=750℃,P=0.1 MPa,进口水...     

中国燃煤发电节能技术的发展及前景

我国一次能源结构决定了发电以煤电为主的基本格局,当前国内火力发电行业需要解决的两大突出问题是高能耗和严重的环境污染。2009年全国发电机组平均供电煤耗341g/(kW.h),高于330g/(kW.h)的国际平均水平。大力发展新型高效节能性火力发电技术,对进一步提高我国火力发电机组的发电效率,减少燃煤大气污染物排放具有十分重要的意义。发达国家正积极发展更高参数的超超临界火力发电技术(600℃/700℃),我国也把"超(超)临界燃煤发电技术"列入"863计划"。可以预见,在我国近中期电力事业的发展中,会把发展更高参数的超临界技术作为火电建设的主要方向。IGCC发电技术是未来煤炭能源系统的基础,被公认为是世界上最清洁的燃煤发电技术。随着煤气化技术和燃气轮机技术的不断发展和进步,IGCC将朝着大容量、高效率、低排放的方向发展。大型直接空冷发电技术是解决我国西北部富煤贫水地区火力发电的有效手段,以2×600MW机组为例,空冷机组比湿冷机组节水约80%左右。通过对火力发电机组各系统的集成与优化,可在现有超超临界机组技术不变的情况下,最大限度地利用余热回收,提高整个机组的发电效率,从而降低煤耗,实现机组在运行过程中的节能。     

Effect of supplementary firing options on cycle performance and CO2 emissions of an IGCC power generation system

Supplementary firing is adopted in combined‐cycle power plants to reheat low‐temperature gas turbine exhaust before entering into the heat recovery steam generator. In an effort to identify suitable supplementary firing options in an integrated gasification combined‐cycle (IGCC) power plant configuration, so as to use coal effectively, the performance is compared for three different supplementary firing options. The comparison identifies the better of the supplementary firing options based on higher efficiency and work output per unit mass of coal and lower CO₂ emissions. The three supplementary firing options with the corresponding fuel used for the supplementary firing are: (i) partial gasification with char, (ii) full gasification with coal and (iii) full gasification with syngas. The performance of the IGCC system with these three options is compared with an option of the IGCC system without supplementary firing. Each supplementary firing option also involves pre‐heating of the air entering the gas turbine combustion chamber in the gas cycle and reheating of the low‐pressure steam in the steam cycle. The effects on coal consumption and CO₂ emissions are analysed by varying the operating conditions such as pressure ratio, gas turbine inlet temperature, air pre‐heat and supplementary firing temperature. The results indicate that more work output is produced per unit mass of coal when there is no supplementary firing. Among the supplementary firing options, the full gasification with syngas option produces the highest work output per unit mass of coal, and the partial gasification with char option emits the lowest amount of CO₂ per unit mass of coal. Based on the analysis, the most advantageous option for low specific coal consumption and CO₂ emissions is the supplementary firing case having full gasification with syngas as the fuel. Copyright © 2008 John Wiley & Sons, Ltd.