热解气催化活化促进石河子烟煤热解的研究

采用等体积浸渍法制备了Fe/MgO,Co/MgO和Ni/MgO催化剂,利用固定床反应器对石河子烟煤在热解气气氛下的催化热解行为进行了研究,考察热解气在催化剂作用下对煤热解焦油产率、半焦产率、轻重油比例以及焦油族组成的影响,并与相同条件下N2气氛和热解气气氛热解特性进行了对比分析.结果表明,三种催化剂对煤在热解气中的热解都有促进作用,其中Ni/MgO催化剂对提高焦油产率最明显.在气体流量为400mL/min,热解温度为550℃,Ni/MgO为催化剂的条件下,焦油产率为7.33%,与相同条件下在N2气氛和热解气气氛下热解相比,焦油产率分别提高了78%和42%.而Co/MgO催化剂对提高轻油的作用较明显.这表明热解气催化活化对煤热解有较好的促进作用,可抑制缩聚反应,提高焦油的产率和改善焦油的品质.     

基于NiO载氧体的煤化学链燃烧实验

采用流化床反应器并以水蒸气作为气化-流化介质,研究了以NiO为载氧体在800～960℃内的煤化学链燃烧反应特性。实验结果表明,载氧体与煤气化产物在反应器温度高于900℃体现了高的反应活性。随着流化床反应器温度的提高,气体产物中CO₂的体积浓度(干基)呈单调递增;CO、H₂、CH₄的体积浓度(干基)呈单调递减;煤中碳转化为CO₂的比率逐渐递增,碳的残余率逐渐递减。反应器出口气体CO₂、CO、H₂、CH₄的生成率随反应时间呈单峰特性,H₂生成率的峰值远小于CO的峰值;且随反应器温度升高,CO₂生成率升高,CO、H₂、CH₄的生成率降低。反应温度高于900℃时,流化床反应器NiO载氧体煤化学链燃烧在9 min之内就基本完成,CO₂含量高于92%。     

反应气氛对平朔煤热解反应性能的影响

在固定床反应器上研究了平朔煤在N2,H2,CH4/CO2和CH4/CO2(catalyst)不同热解气氛下的煤热解性能.主要考察了不同热解气氛下的热解温度和升温速率对焦油、水、半焦产率以及脱硫率的影响.结果表明,甲烷在催化剂的作用下能够产生大量的CHx基团,CHx基团能使煤热解产生的自由基更稳定,从而提高焦油产率.平朔煤在CH4/CO2(catalyst)气氛下热解的焦油产率最高,在600℃的热解温度下,焦油、水、半焦产率和脱硫率分别为33.5%,25.8%,69.5%和25.3%(质量分数),其中焦油产率为相同条件下H2和N2气氛下热解的1.6和1.8倍.     

新疆伊犁南台子煤热解耦合CO变换反应的研究

为探索提高焦油产率的新途径,以新疆伊犁南台子煤为研究对象,考察了CO变换反应与煤热解反应耦合对焦油产率的影响。采用常压固定床反应器,B205为变换催化剂,分别考察了热解气氛、反应温度对南台子煤热解反应的影响。结果表明,CO变换反应与煤热解反应耦合条件下,热解温度在450℃~650℃范围,焦油产率随温度的升高而增大;650℃之后,焦油产率保持稳定。在热解温度650℃、其他反应条件完全一致、CO变换反应与煤热解反应耦合条件下,焦油产率分别为N2、H2气氛中焦油产率的1.62倍和1.43倍。半焦和焦油的红外分析表明,CO变换反应生成的活性氢参与了芳烃的加成反应,使氢数量增多,提高了焦油产率。     

热解温度和反应气氛对输送床煤快速热解的影响

在连续进料量为1.2 kg·h^-1的输送床反应器中考察了热解温度和反应气氛对不连沟次烟煤快速热解的影响。N₂气氛下,随着煤热解温度升高,焦油产率先增加后减小,600℃时达到最大值10.3%;对应的半焦产率下降,气体产率以及气油比增加。高温促进了煤挥发分的释放以及挥发分在气相中的二次反应,部分产物从固相和液相产品转化为气相产品,氢气、甲烷和乙烯等气体组分的产率明显增加。700℃下,H₂气氛能够抑制挥发分二次反应的发生,起到稳定自由基和加氢的作用,显著提高焦油产率和油品品质,同时有利于甲烷的生成。CO气氛在一定程度上同时提高了轻质和重质焦油产率。CO₂和水蒸气能够促进焦油的二次反应,特别是重质焦油的裂解,具有一定的提质作用,但会导致焦油产率下降。CH₄气氛促进了重质焦油组分的生成,使得热解焦油产率提高。     

流化床粉煤热解气化一体化工业试验研究

为了验证流化床热解气化一体化反应器一步法提取焦油与合成气的效果，在处理量为36 t/d的工业试验装置对0～300μm西湾煤进行连续运行试验，考察了热解及气化反应的产物产率及性质。结果表明，在热解温度580℃、气化温度990℃、压力1.0 MPa下，通过加氢气氛、短接触时间与固体颗粒高倍率循环的协同影响，强化床层传热传质和减少产物的二次反应，焦油产率为15.91%,格金焦油产率达到136.57%;焦油密度1.06 kg/m³,含尘量0.87%(质量分数，下同),含水率2.58%,焦油中轻质组分含量57.14%;半焦和灰渣的挥发分降低，硫元素含量减少；合成气中H₂含量(体积分数，下同)29.53%～33.79%,CO含量26.88%～30.05%,热值9 471.03～10 069.09 kJ/m³;标定期间的每小时物料平衡偏差1.27%,热量损失6.90%,碳转化率94.27%,能源转化效率82.75%。工业化试验证明，流化床热解气化一体化反应器可以有效耦合粉煤热解与半焦气化，实现了连续稳定运行，以较高产率制取了高品质焦油...     

气氛对依兰低阶煤流化床快速热解产物分布的影响

利用流化床快速热解反应器对依兰次烟煤快速热解进行了试验研究,分析了气氛条件对热解产物分布的影响。试验结果表明:热解气体产率随热解温度的升高而增加;热解焦油存在最大产率温度,在N_2,H_2,CO和CO_2气氛下对应的最大产率温度分别为670,650,720和700℃;与N_2气氛相比,H_2和CO气氛可提高焦油产率50%以上,CO_2气氛则仅在较高热解温度(650℃)下显著影响焦油产率;通过元素分析,热解气氛中H_2,CO_2和CO的存在可提高焦油的氢碳比,同时降低S和N元素的含量。     

移动床中内构件对煤热解反应过程调控作用

在外热式内构件（多级折流板和多段集气管）移动床反应器内研究了淖毛湖煤的热解特性,并与常规固定床反应器中煤热解行为进行对比,考察了两反应器内的传热速率以及热解温度对产物分布、热解气组成、焦油组成和品质等影响规律。结果表明：在450℃低温热解时,煤颗粒在内构件移动床内的升温时间比固定床缩短了60%以上,内构件具有显著提高反应器内颗粒间传热速率的作用。随着热解温度的升高,热解气中的C₂H₄/C₂H₆和C₃H₆/C₃H₈的比值变大,挥发分的二次反应程度加大,但裂解程度低于固定床。内构件移动床中的焦油产率随温度的升高先增加后降低,在550℃时达到最高为10.8%（质量分数）,比固定床增高约28.6%。当热解温度越高时,移动床所产焦油中的沥青质组分含量越低,在750℃时焦油中轻质组分质量分数达到85.17%,脂肪烃含量降低到了28.00%。通过与固定床对比,揭示了内构件（多级折流板和集气管）调控淖毛湖煤热解反应并提高热解焦油产率和品质的作用。     

磷改性Mo/Al_2O_3-SiO_2催化剂对神府煤催化热解产物的影响

在常压固定床反应器及温度为750℃的氢气气氛下开展了神府煤催化热解研究,讨论了磷改性催化剂对热解气组成和焦油产率的影响。结果表明:10%-Mo/3%-P-Al_2O_3-SiO_2催化剂使得煤热解焦油的收率提升了9.6%,热解气热值提高,催化剂对热解气体产物组成影响较小,其中CH_4的相对含量占到50%以上。焦油的GC-MS分析表明,催化热解可以使焦油中各组分的相对含量有不同程度的变化,证明磷改性催化剂能在一定程度上调整加氢热解产物的分布。     

天然气-煤共气化制备合成气热态模拟

天然气-煤共气化制备通用合成气技术是基于天然气蒸汽转化法和煤气化过程开发的新工艺，通过技术原理分析，可以直接制备出H₂/CO在1.0～2.0之间可调的粗合成气.应用移动床反应器进行热态模拟实验，主要研究了不同操作参数对火焰区温度及合成气有效成分(H₂＋CO)和H₂/CO的影响.结果表明：天然气与氧气在同一位置喷入反应器，控制喷吹参数H₂O/CH₄/O₂以及流量，在气化炉炉温不低于1000 ℃的条件下，煤或焦炭中挥发分基本裂解，可以直接制备出H₂/CO在1.0～2.0之间，有效成分大于90.0%，残留的CH₄小于2.0%的粗合成气.     

Fundamentals of coal topping gasification: Characterization of pyrolysis topping in a fluidized bed reactor

Coal topping gasification refers to a process that extracts the volatiles contained in coal into gas and tar rich in chemical structures in advance of gasification. The technology can be implemented in a reactor system coupling a fluidized bed pyrolyzer and a transport bed gasifier in which coal is first pyrolyzed in the fluidized bed before being forwarded into the transport bed for gasification. The present article is devoted to investigating the pyrolysis of lignite and bituminite in a fluidized bed reactor. The results showed that the highest tar yield appeared at 823 to 923 K for both coals. When coal ash from CFB boiler was used as the bed material, obvious decreases in the yields of tar and pyrolysis gas were observed. Pyrolysis in a reaction atmosphere simulating the pyrolysis gas composition of coal resulted in a higher production of tar. Under the conditions of using CFB boiler ash as the bed material and the simulated pyrolysis gas as the reaction atmosphere, the tar yields for pyrolytic topping in a fluidized bed reactor was about 11.4 wt.% for bituminite and 6.5 wt.% for lignite in dry ash-free coal base.     

Fluidized bed pyrolysis of distilled spirits lees for adapting to its circulating fluidized bed decoupling combustion

Distilled spirits Lees, rich in cellulose, water and N element, are difficult to burn efficiently and cleanly in grate chain stock boiler. The circulating fluidized bed decoupling combustion (CFBDC) was therefore proposed to burn the distilled spirits lees efficiently and with low-NOx emission. The pyrolysis behavior of the distilled spirits lees was investigated in a fluidized bed reactor for optimizing the pyrolysis conditions of the pyrolyzer in CFBDC. The results showed that the distilled spirits lees began to devolatize at 250 °C and at 350–450 °C the tar yield reached its maximum of about 16.3 wt.% (dry base). The chemical oxygen demand (COD) value of the condensed liquid reached its maximum of about 50,000 mg/L at 450 °C. With raising temperature the pyrolysis gas tended to contain more CO and H₂ and less CO₂. The functional groups H-O, aliphatic C-H, aromatic ring, C=O and C-O were all presented in the char generated at low-temperatures, while only the C-O group was identified for the char from the pyrolysis at 650 °C. The article suggested that the pyrolysis for the CFBDC was better around 500 °C so that certain volatiles could remain in the char to sustain stable combustion.     

Pilot Development of Polygeneration Process of Circulating Fluidized Bed Combustion combined with Coal Pyrolysis

A pilot polygeneration process of a 75 t h^–1 circulating fluidized bed (CFB) boiler combined with a moving bed coal pyrolyzer was developed based on laboratory‐scale experimental results. The process operation showed good consistency and integration between boiler and pyrolyzer. Some critical operating parameters such as hot ash split flow from the CFB boiler to the pyrolyzer, mixing of hot ash and coal particles, control of pyrolysis temperature and solid inventory in the pyrolyzer, and pyrolysis gas clean‐up were investigated. Yields of 6.0 wt‐% tar and 8.0 wt‐% gas with a heating value of about 26 MJ m^–3 at 600 °C were obtained. Particulate content in tar was restrained less than 4.0 wt‐% by using a granular filter of the moving bed. Operation results showed that this pilot polygeneration process was successfully scaled up.     

Flash pyrolysis of coals. Devolatilization of bituminous coals in a small fluidized-bed reactor

The devolatilization behaviour of ten bituminous coals was investigated under rapid heating conditions using a small-scale fluidized-bed pyrolyser. The pyrolyser operated continuously, coal particles being injected at a rate of 1–3 g h^?1 directly into a heated bed of sand fluidized by nitrogen. Yields of tar, C₁–C₃ hydrocarbon gases, and total volatile-matter and an agglomeration index are reported for all coals. Maximum tar yields were obtained at about 600 °C and were always substantially higher than those from the Gray-King assay. Total volatile-matter yields were also substantially higher than the proximate analysis values. The maximum tar yields appear to be directly proportional to the coal atomic $\text{H}\text{C}$ ratio. The elemental analysis of the tar is strongly dependent on pyrolysis temperature. The tar atomic $\text{H}\text{C}$ ratio is proportional to that of the parent coal. The effect on the devolatilization behaviour of two coals produced by changes in the pyrolyser atmosphere and the nature of the fluidized-bed material were also investigated. Substituting an atmosphere of hydrogen, helium, carbon dioxide or steam for nitrogen, has no effect on tar yield and, with one exception, little effect on the hydrocarbon gas yields. In the presence of hydrogen the yield of methane was increased at temperatures above 600 °C. Tar yields were significantly reduced on substituting petroleum coke for sand as the fluid-bed material. A fluidized bed of active char virtually eliminated the tar yield.     

流化床稀相段对焦油裂解的影响

为降低煤在热解过程中的焦油产率 ,在一流化床稀相段考察了温度和停留时间对焦油裂解的影响 .结果表明 :焦油转化率随着温度和停留时间的增加而明显提高 ,但其增长幅度却逐渐变小 ,说明继续升高温度和停留时间对降低焦油产率的作用在逐渐减小 .同时温度或停留时间的增加也促进了 H2 ,CO和 CO2 产率的增长 ,对脂肪烃类的影响比较复杂 .在不同温度下 ,气体热值随停留时间的增加均呈下降趋势 .     

不同热解方式下长焰煤的热解特性研究比较

为提高长焰煤热解转化率,研究其热解过程和机理,采用格金干馏设备、固定床和间歇蒸气流化床3种不同热解装置,分别进行长焰煤的低温热解实验。研究结果表明,格金干馏实验中液体产率较高;在固定床低温热解装置中,煤颗粒达到完全热解需要的时间长,热解气体产物中氢气的产率高;在间歇蒸气流化床中,煤颗粒的热解反应速度快,但受热解过程中流化气吹损的影响,半焦产率低;热解气体的组成和分布也随热解气氛而改变,在水蒸气气氛条件下,水蒸气可能参与大分子烃类物质的部分反应,热解气体中CH4和C2以上小分子烃类物质CmHn总含量降低,CO2和CO含量增高。     

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.     

Simulation of coal pyrolysis by solid heat carrier in a moving-bed pyrolyzer

A one-dimensional, steady state, numerical model for coal pyrolysis by solid heat carrier in moving-bed has been developed. The multiple-reaction model of coal pyrolysis and the gas–solid–solid three phases heat transfer theory in packed bed have been applied to account for the pyrolysis process. The results show that the axial temperature distribution of the coal particles increase with a heating rate more than 600 K/min. Coal particle size has significant influence on the heating rate, while blending ratio is the determinant factor of pyrolysis temperature. Given the main operating parameters, product distributions (H₂, CO, CH₄, tar, etc) are calculated by the model. The modeling results are found to agree the experimental data using a moving-bed pyrolyzer with processing capacity 10 kg h^?1 of coal.     

页岩灰和FCC催化剂调控油页岩热解产物二次反应特性

采用两段反应器对油页岩热解初级挥发分进行二次催化反应特性研究,考察了第2段反应器内不同的催化载体、反应气氛与停留时间对油气收率及品质的影响。结果表明,在考察的停留时间范围内页岩灰具有相对适中的催化活性来调控热解挥发分产物的二次反应,水蒸气气氛能够进一步提高热解油收率约5%,并能够在一定程度上抑制裂解气体中C₂~C₃组分的生成。页岩灰作为催化载体能够转化热解油中VGO（馏程>350℃）等重质组分,随停留时间增加油品馏程向轻组分转移。油品组分GC-MS结果表明,较短停留时间内（<3 s）,水蒸气添加能够有效抑制热解油中脂肪烃类的过度裂解,与氮气相比提高汽柴油馏分含量20%以上。过长的停留时间（3~5 s）会造成VGO等馏分缩聚生成焦炭,从而大幅降低热解油收率。