温度和压力对加压喷动流化床煤部分气化的影响

在热输入0.1MW的加压喷动流化床煤部分气化炉上以空气和水蒸气为气化剂,进行徐州烟煤的加压部分气化试验。考察了气化温度、压力等因素对煤气成分、煤气热值、干煤气产气率、碳转化率等指标的影响。气化温度是通过调整空气系数来实现的。试验结果表明:气化温度对煤气化过程影响显著,气化温度升高,煤气热值先增大后减小,产气率增加,碳转化率提高。而增大压力,床内气体速度变慢,延长了气化剂在床内的停留时间,另外压力增加改善了床内的流化质量,从而提高了气化效率,改善了煤气质量。     

煤粉加压气化炉操作参数对气化特性的影响

采用基于平衡态模型的气流床气化炉煤气组分预测程序,分析研究了气化压力、氧煤比以及蒸汽煤比等操作参数对气化温度、煤气组分、碳转化率和气化效率的影响规律。研究结果表明:气化压力对气化特性指标影响甚微,而氧煤比和蒸汽煤比的影响较为显著。随氧煤比的增加,气化温度升高,碳转化率升高,气化效率先升高再降低,CO浓度先增加后降低。CH_4的体积浓度可用于预测气化温度。在蒸汽煤比较低时,提高蒸汽煤比可增加H_2的浓度,提高碳转换率和气化效率,但进一步提高蒸汽煤比仅会降低气化炉内的气化温度,提高H_2O和CO_2浓度。对于所研究的煤种,合理的氧煤比应在0.7左右,合理的蒸汽煤比在0.1左右。     

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...     

油水煤浆在新型气化炉内气化过程的数值模拟

在多喷嘴入口新型水煤浆气化炉内对油水煤浆(COW)的气化过程进行了数值模拟计算研究,分析了气化炉内的温度分布、各种气化产物浓度分布规律。数值模拟计算结果证明,同浓度的油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1.81%,气化炉出口粗煤气中有效气(CO H2)含量提高10.58%,CO2和H2O浓度大幅下降,水分解率大大提高,气化效果明显优于普通水煤浆。     

下吸式生物质气化炉气化性能研究

生物质固定床气化技术具有运行稳定、可提供清洁能源等优点,但也存在气化效率差,燃气热值低的问题.以采用炉膛集中供风技术和还原区热量包裹技术的下吸式气化炉为研究对象,研究护膛温度、空气当量比(ER)对燃气成分、燃气热值、气化效率等气化性能的影响,并与以往研究结果进行对比分析.实验表明,该气化炉能保证在较低ER内(0.1～0...     

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.     

氧煤比对气流床煤气化过程的影响

为研究氧煤比对气流床煤气化炉气化过程的影响,对某厂运行的Texaco气化炉进行了数值模拟研究。利用所建立的数学模型,分析了Texaco气化炉内的气化过程,以及氧煤比对炉内温度、气相成分及炉膛出口合成气成分的影响规律。结果表明:Texaco气化炉内下行火焰的长度约占气化炉高度的1/3,炉膛上部火焰高度区域内气相温度及主要成分浓度的变化梯度最大,而在炉膛下部气相成分及温度的变化均不明显;随着氧煤比的增大(0.95~1.10),气化炉出口合成气有效成分(H2+CO)浓度逐渐降低,CO2和H2O的浓度及气化炉内气相温度逐渐升高;在保证顺利排渣和合适的出口合成气成分的条件下,存在一个最佳氧煤比。     

废轮胎整胎与生物质共气化实验研究

以树枝秸秆及废轮胎整胎为原料,在"反烧"式固定床气化炉中以空气为气化剂进行气化实验研究。结果表明,随着空气当量比ER的增加,炉内气化温度升高,气化效率提升,当ER为0.30时,炉内温度达到750℃,气化效率为56.45%,气体热值为4.68 MJ/m3;随着原料中废轮胎比例的增加,气化效率有所提高,燃气热值升高,当废轮胎质量含量为44%时,气化效率达到60.21%,气体热值为5.34 MJ/m3;气化温度是影响气化效率和气体热值的最重要因素,提高空气当量比可以使炉内温度升高,强化气化效果;同时原料中废轮胎比例也对气化效率及气体热值有较大影响,废轮胎质量含量为40%~50%较为适宜。废轮胎以整胎形式与生物质共气化是废轮胎处置与资源化利用的有效方式。     

上吸式固定床生物质气化炉模拟优化

为了提高上吸式固定床生物质气化炉的燃气产物产量和品质,通过模拟试验对气化炉进行优化设计,使生物质气化炉装置的流场分布均匀,氧化层和还原层反应充分。通过热态试验分析生物质气化炉炉内床层温度分布、燃气产物成分、气化强度、产气率与入炉空气量的关系,得到该上吸式固定床生物质气化炉的最佳入炉空气量条件。结果显示：优化设计后的气化炉气化效率达到70%以上,有效提高了生物质炉的气化能力。     

氧气纯度对两段式煤粉气化炉气化特性的影响

降低氧气纯度可以显著地降低空分能耗,对于提高IGCC电厂整体效率有着积极的意义.不过氧气纯度过低(低于95％),偏离设计工况参数,会对IGCC两段式干煤粉气化炉内温度、合成气组分以及气化效率造成一定的影响.为了探究氧气纯度对于IGCC两段式干煤粉气化炉内气化特性的影响,采用流程仿真软件Aspen Plus和数值模拟软件...     

Pressurized drop tube furnace tests of global coal gasification characteristics

Pressurized drop tube furnace (PDTF) tests were performed with an Indonesian sub‐bituminous coal while temperature, oxygen/coal ratio, steam/coal ratio and pressure were systematically varied. The tests were designed to investigate the effects of these experimental parameters on the pulverized coal gasification characteristics at elevated pressure. The results showed that the gasification at elevated pressure is more productive than that at atmospheric pressure, considering the carbon conversion and cold gas efficiency. The oxygen/coal ratio at the maximum cold gas efficiency ranged between 0.5 and 0.7 g/g. Only when the temperature was sufficiently high, did the increase of steam/coal ratio result in the improvement of cold gas efficiency. As the pressure increased, the contribution of carbon conversion by heterogeneous reactions increased while the conversion by pyrolysis decreased. Copyright © 2000 John Wiley & Sons, Ltd.     

两段式水煤浆气化炉气化参数对IGCC系统性能的影响

采用Thermo Flex软件建立了基于两段式水煤浆气化技术的200MW级IGCC系统模型,研究了气化温度、水煤浆浓度、气化压力、氧气纯度等气化参数对系统性能的影响.结果表明：提高反应温度和气化压力,系统的供电效率和发电效率降低;氧气纯度增加,供电效率上升;在相同气化温度（或气化压力、氧气纯度）的情况下,提高二段给煤比γsc,系统性能可以得到有效改善;当水煤浆浓度变化时,氧煤质量比随γsc改变进行调整才能达到设计值碳转化率的要求.     

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.     

Experimental study on coal multi-generation in dual fluidized beds

An atmospheric test system of dual fluidized beds for coal multi-generation was built.One bubbling fluidized bedis for gasification and a circulating fluidized bed for combustion.The two beds are combined with two valves:one valve to send high temperature ash from combustion bed to the gasification bed and another valve to sendchar and ash from gasification bed to combustion bed.Experiments on Shenhua coal multi-generation were madeat temperatures from 1112 K to 1191 K in the dual fluidized beds.The temperatures of the combustor are stableand the char combustion efficiency is about 98%.Increasing air/coal ratio to the fluidized bed leads to theincrease of temperature and gasification efficiency.The maximum gasification efficiency is 36.7% and thecalorific value of fuel gas is 10.7 MJ/Nm3.The tar yield in this work is 1.5%,much lower than that of pyrolysis.Carbon conversion efficiency to fuel gas and flue gas is about 90%.     

高温快速加热条件下压力对煤气化反应特性的影响

建立了一套能同时实现高温高压和快速加热的实验设备和研究方法,使煤气化反应动力学基础研究能在与实际气流床煤气化炉相近的条件下进行.研究表明,当CO2体积分数相同时,最大CO生成速度随压力的升高而升高;煤焦的气化反应速度随全压的升高而升高.即使全压和CO2体积分数不同,只要CO2的分压、温度等其他条件相同,煤焦的气化反应速度就基本上一致.说明全压和CO2体积分数对煤焦气化反应速度的影响可以归纳为CO2分压的影响.高温快速加热条件下,除了温度以外,CO2分压是影响煤气化特性的重要因素.     

Study on pulverized coal gasification using waste heat from high temperature blast furnace slag particles

A combined species transport and reaction-discrete phase model was established to numerically study pulverized coal gasification using waste heat from high temperature slag particles. The effects of slag particles temperature, coal/gasification agent mass ratio and water content in gasification agent on the gasification characteristics were discussed. The results indicate that higher particle temperature leads to better gasification reaction efficiency. Compared to the maximum syngas productivity (67.9%) and carbon conversion efficiency (91.7%) at 1500 K, they are respectively reduced to about 45% and 60% when temperature drops to 1000 K. Excessive or insufficient pulverized coal would have a negative effect on the syngas production for a specific flow rate of gasification agent, and the appropriate proportion range is 0.8–0.84. The CO yield declines with the increase of particles diameter, while H₂ firstly increases and then declines attributing to the lower gasification agent temperature and higher flow velocity gained at larger diameter. The raise of water content in gasification agent is beneficial to H₂ production, but CO yield continues to decline after the water content exceeds 5% for the reason that the incomplete combustion of volatiles and the gasification reaction of coke are inhibited. The diameter of slag particles and the water content suitable for coal gasification reaction are 2.0–2.5 mm and 5%–10%, respectively.     

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。     

燃煤气的闭式STIG循环中气化系统能量转化效率的研究

针对燃煤气的闭式ＳＴＩＧ循环,给出气化系统能量转化效率的计算式,计算三种典型气化炉分别采用高温干法和常温湿法净化系统的能量转化效率,同时分析能量转化效率对整个循环系统效率的影响。     

800MWe超临界循环流化床锅炉概念设计

常压循环流化床 (ACFB)燃烧技术是已经为国际上公认的商业化程度最好的洁净煤技术 ,但在达到较高的供电效率方面并未具有明显的优越性。超临界CFB作为下一代CFB技术 ,综合了超临界蒸汽循环高效率和循环流化床低成本 2方面的优势 ,而循环流化床条件下的热负荷分布规律使得超临界压力下水冷壁的安全性更为可靠 ,脱硫、脱硝投资及运行成本比烟气脱硫和催化还原NOx 低 ,受到人们的高度关注。总结了国内外超临界CFB锅炉研究工作的一些进展 ,详细介绍了 80 0MWe超临界CFB锅炉的概念设计。     

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。