新型固定床气化模拟及验证

为探究新型固定床气化炉工艺操作条件。选用低阶煤,煤颗粒平均粒径10 mm,加煤量35 kg/h,氧气量10 m³/h,运行压力设定为0.1 MPa进行试烧试验。分别进行Fluent动力学数值模拟与Aspen Plus热力学数值模拟,与实际试烧数据对比。结果表明,Fluent模拟的上出气口CO、H₂、CH₄、CO₂体积分数与试烧的绝对误差分别为0.027、0.010、0.020、-0.057,下出气口CO、H₂、CH₄、CO₂模拟体积分数与试烧绝对误差分别为-0.038、0.007、0.003、0.037,而Aspen Plus上出气口CO、H₂、CH₄、CO₂模拟体积分数与试烧的绝对误差分别为0.025、-0.028、0.012、-0.009,下出气口CO、H₂、CH₄、CO₂模拟体积分数与试烧数值的绝对...     

不同反应器中氧化反应与水蒸气气化反应协同作用差异性

在?80mm×3000mm气流床和?40mm×200mm流化床中进行了O₂、H₂O、H₂O+O₂气氛下800℃胜利褐煤气化实验，同时在流化床中进行了O₂、H₂O、H₂O+O₂气氛下半焦原位气化实验和H₂O气氛下半焦完全气化实验。比较了2种反应器中氧化反应与水蒸气气化反应协同作用的大小（强弱）；结合实验条件利用缩核模型分别推导了2种反应器中协同作用影响下水蒸气气化反应速率方程；同时，从传质（扩散）速率、动力学、半焦-挥发分相互作用3方面探讨了2种反应器中协同作用存在显著差异的原因。结果发现，气流床中H₂O+O₂气氛下褐煤转化率明显大于H₂O和O₂单独气氛下褐煤转化率之和，其差值稳定在2.11%～4.01%，而在流化床中差值仅为0～0.75%，相对流化床，气流床中协同作用更明显。这是由于，在流化床中水蒸气向炭粒表面扩散的传质速率约为气流床的11%～25%，水蒸气气化过程受气膜扩散控制，炭粒表面水蒸气全部参与气化反应，炭粒表面无“多余”水分子，氧气开孔/扩孔作用提供的活性位“闲置”，而气流床中气化反应为速控步，炭粒表面有“富裕”水分子，可充分利用氧气开孔/扩孔作用提供的活性位，促进作用显著；挥发分-半焦相互作用不是流化床反应器中协同作用不显著的原因。     

胜利褐煤水蒸气气化制富氢合成气及其固有矿物质的催化作用

利用微型固定床反应装置,研究了内蒙古胜利褐煤水蒸气气化过程中H₂、CO₂、CO和CH₄生成规律及其固有矿物质的催化效应。原煤(SL-raw)、盐酸洗脱(SL-HCl)、氢氟酸洗脱(SL-HF)及盐酸洗脱液回添煤样(SL-HCl-Re)在水蒸气气化反应过程中,H₂、CO₂和CO生成速率存在明显差异,充分说明胜利褐煤中某些固有的矿物质对其水蒸气气化反应具有显著的催化作用,可大幅度提高其气化反应速率,并使其起始气化温度降低96℃,气化反应主体温度降低150℃以上,同时促进了合成气中H₂生成,抑制了CO的生成,使胜利褐煤水蒸气气化反应过程中一直维持着较高的H₂/CO摩尔比,SL-raw、SL-HCl-Re水蒸气气化所得合成气中H₂/CO摩尔比分别为17.3和4.3,而SL-HCl和SL-HF水蒸气气化所得合成气中H₂/CO摩尔比均只有1.22。SL-HCl和SL-HF水蒸气气化生成H₂、CO₂和CO的规律基本相同,说明起催化作用的物质是可溶解在盐酸洗脱液中的矿物质。经过分析,发现矿物质对胜利褐煤水蒸气气化反应的催化作用主要是通过提高水煤气变换反应(WGSR)速度实现的。最后结合文献报道提出了胜利褐煤水蒸气气化反应过程中矿物质的原位催化机理。     

褐煤热解-气化-制油系统的CO2减排策略

褐煤热解-气化-制油系统是现代煤化工发展的一个重要研究内容。来自系统多个单元产生的CH₄和CO₂如果发生重整反应,将重整得到H₂/CO比值较高的合成气添加到制油流程中,可实现更多的C被固定到产品中而减少CO₂的直接排放量。对CH₄-CO₂和CH₄-H₂O两种重整反应方式、来自煤热解和费托合成两股甲烷气和典型的干粉气化和水煤浆气化两种流程进行了组合研究。分析结果显示,来自热解和费托合成的甲烷重整后不足以提供调节合成气H₂/CO比例所需的氢气,水煤气变换反应对于褐煤制油系统来说是必需的。从C转化成油的角度来看,采用干粉气化和CH₄-H₂O重整的方案是较好的选择。     

淖毛湖煤加氢热解产物特性及半焦气化反应性

在加压固定床反应器中进行淖毛湖煤在常压和1.5 MPa氢气和氮气中的热解试验,利用多种表征方法对比研究了氢气和氮气下的热解产物产率和组成及半焦结构的变化,并利用热重分析研究热解半焦的CO₂气化反应性。结果表明：与常压N₂中热解相比,煤在加压的H₂中热解可有效提高热解气体中CH₄和C₂～C₃的产率,在800℃热解CH₄和C₂～C₃的体积产率分别由53.5和16.6 mL/g增至345.6和20.8 mL/g。焦油和轻质焦油产率也有效提升,在600℃下,与常压N₂中热解相比,1.5 MPa H₂中煤热解的焦油产率由19.3%升至22.8%,焦油中脂肪烃含量由35.5%降至14.8%,单环芳烃含量由8.3%增至28.9%,轻质焦油质量分数和产率分别升至95.0%和21.8%。半焦的N₂吸附和拉曼光谱分析结果表明,煤在加压H_...     

木屑炭水蒸气气化制备合成气

以木屑炭为原料,在上吸式固定床气化炉中进行水蒸气气化制备合成气,考察了温度和水蒸气流量对木屑炭水蒸气气化的产物分布、炭转化率、产气率、组成含量和H₂/CO值的影响。结果表明：升高温度有助于木屑炭气化,炭转化率和产气率分别在950 ℃下达到最大值99.2%和4.16 L/g,但温度升高会导致H₂从65.8%降至61.2%,同时H₂/CO也呈下降趋势,从10.3降至3.35;水蒸气流量的增加可提升H₂,从59.8%升至62%,但流量升至0.6 g/min时气化结果趋于稳定。水蒸气气化的最佳操作条件为900 ℃,水蒸气流量0.6 g/min,此条件下炭转化率、产气率和热值分别达到93.3%、4.06 L/g和9.04 MJ/m³,H₂/CO值为4.11,适合于合成甲烷。     

水蒸气/氧流化床两段煤气化制备低焦油合成气工艺实验

由下行床热解和提升管（或输送床）气化组合形成的流化床两段气化将煤气化反应过程解耦为煤热解和半焦气化两个反应阶段,热解产物完全进入气化反应器,利用其中的高温环境和输送的半焦催化作用分别实现焦油的热裂解与催化裂解,完成低焦油气化。利用该流化床两段气化的10 kg/h级实验室工艺实验装置,以榆林烟煤为原料、水蒸气/氧气作为气化剂,变化过量氧气系数ER、蒸汽炭比S/C、热解及气化温度等参数,研究水蒸气/氧流化床两段煤气化制备低焦油合成气的特性。结果表明,流化床两段气化系统可实现稳定运行（实验3 h以上）,在ER=0.36和S/C=0.15时,热解和气化的代表温度分别稳定在735℃和877℃,合成气的CO、CO₂、H₂、CH₄、C _n H _m 和N₂含量分别为14.33%、10.07%、18.39%、9.89%、1.82%和45.50%,相应的合成气产量达到1.8 m³/kg,低位热值8.99 MJ/m³,焦油含量0.437 g/m³,展示了制备低焦油合成气的技术特征。对于实际的长时间连续运行,更高的气化温度将使流化床两段气化具有更好的低焦油特性。     

水蒸气/氧流化床两段煤气化制备低焦油合成气工艺实验

由下行床热解和提升管（或输送床）气化组合形成的流化床两段气化将煤气化反应过程解耦为煤热解和半焦气化两个反应阶段,热解产物完全进入气化反应器,利用其中的高温环境和输送的半焦催化作用分别实现焦油的热裂解与催化裂解,完成低焦油气化。利用该流化床两段气化的10 kg/h级实验室工艺实验装置,以榆林烟煤为原料、水蒸气/氧气作为气化剂,变化过量氧气系数ER、蒸汽炭比S/C、热解及气化温度等参数,研究水蒸气/氧流化床两段煤气化制备低焦油合成气的特性。结果表明,流化床两段气化系统可实现稳定运行（实验3 h以上）,在ER=0.36和S/C=0.15时,热解和气化的代表温度分别稳定在735℃和877℃,合成气的CO、CO₂、H₂、CH₄、C _n H _m 和N₂含量分别为14.33%、10.07%、18.39%、9.89%、1.82%和45.50%,相应的合成气产量达到1.8 m³/kg,低位热值8.99 MJ/m³,焦油含量0.437 g/m³,展示了制备低焦油合成气的技术特征。对于实际的长时间连续运行,更高的气化温度将使流化床两段气化具有更好的低焦油特性。     

市政污泥中低温气化及重金属迁移转化特性

利用管式炉进行了污泥CO₂气化实验,并与N₂热解实验进行对比,系统研究了污泥中低温气化及重金属迁移转化特性。研究发现：热解过程中各可燃气体释放速率峰值出现的时间顺序为CO峰 < H₂次峰 < CH₄峰≈C_nH_m峰 < H₂主峰,气化过程中为CO主峰 < CH₄峰≈C_nH_m峰 < H₂主峰 < CO次峰。在450~550℃的区间内,气化和热解的冷煤气效率、样品失重率及残渣含碳量均相近,温度超过550℃冷煤气效率差距逐渐增大,温度超过700℃,样品失重率及残渣含碳量差距逐渐增大。气化温度为850℃时,冷煤气效率达87%。在450~700℃的区间内,气化残渣中Cr、Ni、Cu、Zn、As、Pb的残留率均随温度增加呈缓慢降低的趋势,在700~850℃区间,上述重金属的残留率下降较快。Cd的残留率在450~550℃区间缓慢下降,550~700℃区间快速降低,700~850℃区间缓慢降低。气化残渣中Cr、Ni、Zn、As、Cd的稳定形态所占比例相较于污泥原样明显提高,而Pb、Cu的稳定形态所占比例与污泥原样相近。污泥中温（700℃）气化时,冷煤气效率约为50%,气化残渣中Cr、Ni、Cu、Zn、As的残留率约为高温（850℃）下的1.2倍,Pb约为2.7倍,Cd为7.5倍,残渣中各重金属的稳定形态比例与高温时接近,环境危害性小。     

高温煤焦气化反应的Langmuir-Hinshelwood动力学模型

应用基于吸附和脱附原理的Langmuir-Hinshelwood （L-H） 动力学模型来描述煤焦在H₂O和CO₂混合气氛下的气化反应时,存在单独活性位和相同活性位两个相互矛盾的假设。在管式炉实验装置内考察了在不同气化温度和气化剂分压的条件下,内蒙煤焦（NMJ）与H₂O和CO₂的气化反应特性,获得了NMJ-H₂O 和NMJ-CO₂反应的L-H动力学模型,同时考察了H₂、CO对煤焦气化反应的抑制作用,并探究了NMJ在H₂O和CO₂混合气氛下的气化反应机理。研究结果表明：NMJ-H₂O以及NMJ-CO₂反应的活化能分别为214.78 kJ·mol^-1和145.96 kJ·mol^-1。H₂对NMJ-H₂O以及CO对NMJ-CO₂的反应存在明显的抑制作用,且CO的抑制作用随反应温度的降低而愈加明显。基于L-H动力学模型计算得到的反应速率曲线与实验结果十分吻合。对于NMJ在H₂O和CO₂混合气氛下的气化反应,基于相同活性位假设的L-H模型的反应速率预测值与实验结果吻合,更加适用于NMJ在混合气氛下的气化反应机理。     

Gasification of lignite and hard coal with air and oxygen enriched air in a pilot scale ex situ reactor for underground gasification

The main goal of the study presented in the paper was an experimental comparison of the underground lignite and hard coal seams air gasification simulated in the ex situ reactor. In the study lignite and hard coal were gasified with oxygen, air and oxygen enriched air as gasification agents in the 50- and 30-h experiments, respectively, with an intrinsic coal and strata moisture content as a steam source. Application of air as a sole gasification agent was problematic for a resulting rapid decrease in temperatures, deterioration of gas quality and, finally, cessation of gasification reactions. Use of oxygen/air mixture of an optimum ratio led to valuable gas production. In lignite seam gasification with oxygen/air (of 4:2 volume ratio) the average H₂ and CO contents in product gas were 23.1 vol.% and 6.3 vol.%, respectively, and the calorific value was 4.18 MJ/m³, whereas in hard coal gasification with the oxygen/air ratio (of 2:3 volume ratio) the average H₂ and CO contents in produced gas were 18.7 vol.% and 17.3 vol.%, respectively, and product gas calorific value equaled 5.74 MJ/m³.     

Effect of operating parameters on methanation reaction for the production of synthetic natural gas

Concerns about the depletion and increasing price of natural gas are generating interest in the technology of synthetic natural gas (SNG) production. SNG can be produced by the methanation reaction of synthesis gas obtained from coal gasification; this methanation reaction is the crucial procedure for economical production of SNG. We investigated the effect of operating parameters such as the reaction temperature, pressure, and feed compositions (H₂/CO and CO₂/CO ratios) on the performance of the methanation reaction by equilibrium model calculations and dynamic numerical model simulations. The performance of the methanation reaction was estimated from the CO conversion, CO to CH₄ conversion, and CH₄ mole fraction in the product gas. In general, a lower temperature and/or higher pressure are favorable for the enhancement of the methanation reaction performance. However, the performance becomes poor at low temperatures below 300 °C and high pressures above 15 atm because of limitations in the reaction kinetics. The smaller the amount of CO₂ in the feed, the better the performance, and an additional H₂ supply is essential to increase the methanation reaction performance fully.     

基于固定床气化废水的褐煤水热提浓制浆

针对煤化工产业存在的"煤头水尾"制约难题,提出采用水煤浆气化技术耦合消纳褐煤（末煤）和废水的思路。对某代表性煤制合成天然气示范项目（SNG）固定床气化装置的5组褐煤及8组废水（W1~W8）、参照组去离子水（W0）进行了组分分析和直接制浆试验,并开展了水热处理制浆试验。研究结果表明：褐煤固定床气化废水有机质和盐含量总体较高,W8固含量达35.1%。褐煤直接制浆时,W1~W7所制水煤浆浓度介于46%~53%,与W0的制浆效果相当,W8所制水煤浆的浓度低于45%;褐煤经300℃水热处理后,分别采用W0和W4的制浆浓度总体超过58%、56%,比直接制浆浓度提高5.5%~11.7%（绝对值）,满足水煤浆气化需求。本研究思路有利于耦合利用褐煤与废水,进而拓宽褐煤（末煤）的应用范围和促进废水的资源化、减量化。     

移动床煤与天然气共气化制备合成气的工艺技术

煤与天然气共气化是基于天然气蒸汽转化和煤气化工艺耦合的一种新工艺.阐述了煤与天然气共气化制合成气的技术原理.实验研究表明合成气最佳出口温度为1000 ℃,氧气、水蒸气和天然气在同一位置进入反应器能有效降低火焰区温度;理论计算得到的合成气有效气体浓度（CO+H₂）大于95%.实验研究和理论计算结果都表明,煤与天然气共气化可以直接得到H₂/CO在1.0～1.5之间可以调节的合成气.     

Potassium-catalyzed steam gasification of petroleum coke for H2 production: Reactivity, selectivity and gas release

Potassium-catalyzed steam gasification of petroleum coke for H₂ production was performed using a laboratory fixed-bed reaction system with an on-line quadruple mass spectrometer. The gasification reactivity, gasification selectivity and gas release for the catalytic gasification were investigated, compared with the non-catalytic gasification. The catalytic gasification could not only effectively promote these reactions (the water-carbon reaction, the water-gas shift reaction and the methane-steam reforming reaction), but also elevate greatly the gasification selectivity towards CO₂ (a high gasification selectivity towards CO₂ meant a high H₂ production). A quantitative calculation method for the gasification selectivity towards CO and CO₂ was proposed to further understand the catalytic behaviors of catalysts. In the case of catalytic gasification, the gasification temperature had opposite effects on the gasification reactivity and the gasification selectivity towards CO₂, suggesting that there existed an optimum gasification temperature (about 750 °C) for H₂ production from the potassium-catalyzed steam gasification of petroleum coke. In addition, petroleum coke could be feasibly utilized as the feedstocks for the catalytic steam gasification to produce gases with high H₂ (55.5-60.4%) and virtually no CH₄ (below 0.1%).     

Catalysis of gasification of coal-derived cokes and chars

Calcium is the most important in-situ catalyst for gasification of US coal chars in O₂, CO₂ and H₂O. It is a poor catalyst for gasification of chars by H₂. Potassium and sodium added to low-rank coals by ion exchange and high-rank coals by impregnation are excellent catalysts for char gasification in O₂, CO₂ and H₂O. Carbon monoxide inhibits catalysis of the CH₂O reaction by calcium, potassium and sodium; H₂ inhibits catalysis by calcium. Thus injection of synthesis gas into the gasifier will inhibit the CH₂O reaction. Iron is not an important catalyst for the gasification of chars in O₂, CO₂ and H₂O, because it is invariably in the oxidized state. Carbon monoxide disproportionates to deposit carbon from a dry synthesis gas mixture (3 vol H₂ + 1 vol CO) over potassium-, sodium- and iron-loaded lignite char and a raw bituminous coal char, high in pyrite, at 1123 K and 0.1 MPa pressure. The carbon is highly reactive, with the injection of 2.7 kPa H₂O to the synthesis gas resulting in net carbon gasification. The effect of traces of sulphur in the gas stream on catalysis of gasification or carbon-forming reactions by calcium, potassium, or sodium is not well understood at present. Traces of sulphur do, however, inhibit catalysis by iron.     

现代煤气化技术发展趋势及应用综述

现代煤气化技术是现代煤化工装置中的重要一环,涉及整个煤化工装置的正常运行。本文分别介绍了中国市场各种现代煤气化工艺应用现状,叙述汇总了其工艺特点、应用参数、市场数据等。包括第一类气流床加压气化工艺,又可分为干法煤粉加压气化工艺和湿法水煤浆加压气化工艺。干法气化代表性工艺包括Shell炉干煤粉气化、GSP炉干煤粉气化、HT-LZ航天炉干煤粉气化、五环炉(宁煤炉)干煤粉气化、二段加压气流床粉煤气化、科林炉(CCG)干煤粉气化、东方炉干煤粉气化。湿法气化代表性工艺包括 GE水煤浆加压气化、四喷嘴水煤浆加压气化、多元料浆加压气化、熔渣-非熔渣分级加压气化(改进型为清华炉)、E-gas(Destec)水煤浆气化。第二类流化床粉煤加压气化工艺,主要有代表性工艺包括U-gas灰熔聚流化床粉煤气化、SES褐煤流化床气化、灰熔聚常压气化(CAGG).第三类固定床碎煤加压气化,主要有代表性工艺包括鲁奇褐煤加压气化、碎煤移动床加压气化和BGL碎煤加压气化等。文章指出应认识到煤气化技术的重要性,把引进国外先进煤气化技术理念与具有自主知识产权的现代煤化工气化技术有机结合起来。     

Gasification of coal and PET in fluidized bed reactor

Blended fuel comprising 23 wt.% polyethyleneterephthalate (PET) and 77 wt.% brown coal was gasified in an atmospheric fluidized bed gasifier of laboratory-scale. The gasification agent was composed of 10 vol.% O₂ in bulk of nitrogen. Thermal and texture analyses were carried out to determine the basic properties of the fuel components. The influence of experimental conditions, such as the fluidized bed and freeboard temperatures on major and minor gas components and tar content, as well as features of the blended fuel gasification in comparison with the single coal gasification, were studied. In the case of coal with PET gasification, only the fluidized bed temperature showed significant influence on CO, CO₂, CH₄ and H₂ content in the producer gas, whereas the effect of the freeboard temperature was insignificant. In single coal gasification both temperatures had considerable and almost the same influence. The content of minor components, such as ethane, ethylene, acetylene and benzene, was found to be more dependent on the freeboard temperature than on the fluidized bed temperature. It was observed that the higher the freeboard temperatures get, the lower is the concentration of the minor components, with the exception of acetylene. The absolute contents of almost all minor and tar components were approximately three times higher in blended fuel gasification than that in single coal gasification. Finally, partition of carbon (char) and selected metals into bottom and cyclone ash in gasification of both fuels is discussed.     

Plastic waste elimination by co-gasification with coal and biomass in fluidized bed with air in pilot plant

Treatment of plastic waste by gasification in fluidized bed with air using dolomite as tar cracking catalyst has been studied. The gasifier has a 1 m high bed zone (diameter of 9.2 cm) followed by a 1 m high freeboard (diameter of 15.4 cm). The feedstock is composed of blends of plastic waste with pine wood sawdust and coal at flow rates of 1–4 kg/h. Operating variables studied were gasifier bed temperature (750–880 °C), equivalence ratio (0.30–0.46), feedstock composition and the influence of secondary air insertion in freeboard. Product distribution includes gas and char yields, gas composition (H₂, CO, CO₂, CH₄, light hydrocarbons), heating value and tar content in the flue gas. As a result, a gas with a medium hydrogen content (up to 15% dry basis) and low tar content (less than 0.5 g/m_n³) is obtained.     

Kinetic studies of char gasification by steam and CO2 in the presence of H2 and CO

Char-CO₂ gasification reactions in the presence of CO and char-steam gasification reactions in the presence of H₂ were studied at the atmospheric condition using a thermogravimetric apparatus (TGA) at various reactant partial pressures and within a temperature range of 1123 K-1223 K. The char was prepared from a lignite coal. The partial pressure of H₂ and CO varied from 0.05 to 0.3 atm. The experimental results showed that Langmuir-Hinshelwood (L-H) kinetic equation was applicable to describe the inhibition effects of CO and H₂. The kinetic parameters in L-H equations were obtained. Interactions of char gasification by steam and CO₂ in the presence of H₂ and CO were discussed. It was found that the kinetic parameters determined from pure or binary gas mixtures can be used to predict multi-component gasification rates. The results confirmed that the char-steam and char-CO₂ reactions proceed on separate active sites rather than common active sites.