焦化焦油脱水新技术

焦化焦油脱水新技术镇江焦化厂研制成功焦化焦油脱水新技术，填补了国内空白，产生良好的经济效益。焦化焦是以石油焦为主要原料生产的一种特种焦炭，由于其工艺和炼焦原料的特殊性，在炼焦过程中产生的焦化焦油．常规脱水装置无法处理，只能作为燃料，经济价值很低，一直...     

首钢预处理煤炼焦的产物特性研究

以首钢焦化厂常规炼焦配煤和预处理加工后炼焦用煤为实验原料,利用200kg焦炉和2kg焦炉进行对比炼焦实验研究。其中,首钢预处理炼焦煤增大了堆密度,减小了含水率。通过实验研究可得出如下结论:预处理煤炼焦的焦炭质量明显改善;采用首钢预处理煤炼焦,能提高生产能力,减少焦化废水;预处理煤炼焦的副产品中,焦油中芳香烃含量增加,煤气中氢气含量增加,甲烷含量减少;在工艺条件允许的情况下,尽量提高炼焦煤的堆密度和降低炼焦煤的含水率,有益于提高焦炭质量、提高炼焦产能和减少焦化废水。     

焦炉煤气干法冷却新工艺的试验研究

分析了常规焦炉煤气净化工艺存在的问题，提出了一种新型的焦炉煤气干法冷却工艺，并在外热式固定床上，以炼焦配煤为原料，就焦炉煤气焦油干法冷却分离进行了试验研究。试验结果表明，焦炉煤气干法冷却工艺中焦油分阶段冷凝分离收集的效果很明显，绝大部分焦油馏分能在系统设计的冷凝温度段内实现冷凝分离。     

生物质焦油/柴油超声乳化工艺及其燃烧特性研究

文章利用超声波乳化技术将焦油与柴油进行乳化提质,分别从焦油含量、HLB值、乳化剂添加量、助乳剂种类4个乳化参数以及超声功率密度、超声作用时间两个超声参数对生物质焦油/柴油乳化体系进行优化工艺研究,并利用热重方法对乳化油进行燃烧特性分析。研究结果表明:当焦油体积含量为7%,HLB值为5,乳化剂的体积含量为5%,助乳剂为甲醇,超声功率密度为0.96 W/mL,超声作用时间为20 min时,乳化油的稳定性最好,稳定时间达到104 min,浊度值为226.08;对生物质焦油、柴油、乳化油进行燃烧特性分析,发现乳化油与柴油具有相似的燃烧特性。     

关于山西煤炭转化发展的探讨

对山西煤炭转化提出建议。发展炼焦、焦油加工、炭素、型煤、煤矸石加工等产业 ,使其尽快成为山西新的支柱产业、新的经济增长点。以促进山西经济的可持续发展     

生物质气化过程中焦油形成机理的研究

以谷壳气化过程中产生焦油为研究对象,考查了在不同温度情况下的焦油组成变化。实验结果表明:温度的不同,气化过程中产生的焦油组成也不同,且随温度的升高,低温中形成的焦油组成会发生热裂解进行二次反应,生成新的焦油组成。通过对焦油的GC-MS分析说明,随温度升高,焦油组分的变化是一个脱氧且芳香化程度增大过程,当达到800℃以上时,焦油中的主要组份以多环芳烃为主,从而为生物质气化过程中焦油催化裂解催化剂的开发指明方向。     

生物质气化发电燃气焦油脱除方法的探讨

生物质气化发电技术的最大难点之一就是如何除去燃气中含有的焦油等污染物,这些成分会对燃气轮机或内燃机等设备造成一定的影响.因此生物质气化发电过程中燃气焦油的脱除是目前国内外重点研究和解决的课题之一.文章在研究国内外大量有关文献资料的基础上,深入阐述了气化过程中焦油产生的机理、影响焦油生成的因素以及焦油的脱除方法,重点探讨了目前较为有效的焦油热化学脱除方法,即焦油的热裂解和催化裂解方法,以期为生物质气化发电燃气焦油的脱除提供一些思路和参考.     

生物质气化焦油脱除过程参数优化方法

焦油是生物质气化过程中的有害产物,它会降低燃气品质,对气化设备及后续用气设备产生危害.本文通过对生物质气化过程中影响焦油生成量的因素进行分析,依据最小二乘曲线拟合原理和目标规划理论建立了生物质料木屑气化过程焦油脱除的参数优化模型,在此基础上采用遗传算法对焦油脱除过程优化模型进行参数寻优.计算结果表明,当气化温度为796.6℃、当量比为0.203时,木屑气化的焦油生成量最小.     

煤液化残渣在配煤炼焦领域的高附加值应用研究

为实现对煤液化后的残渣进行高附加值利用,结合炼焦配煤相关原理和对残渣提纯物进行研究分析,采用替代对比的试验方法,对残渣萃取后的不同灰分提纯物进行配煤炼焦试验,分析各组分含量和质量指标对炼焦过程的影响,研究表明煤液化残渣的低灰提纯物在炼焦过程中配入5％左右后可以改善煤在热解过程中形成胶质体的数量、粘度和强度等性能指标,起...     

谷壳热解/水蒸气气化焦油析出特性研究

在固定床上开展谷壳热解和水蒸气气化实验,通过使用冷捕集法收集实验过程中形成的焦油,并对其进行GC/MS成分和重量分析,从而研究热解和水蒸气气化过程中焦油析出的不同特性并考察温度、水蒸气和催化剂等因素对水蒸气气化焦油析出的影响。研究表明:在实验工况下,焦油组分主要为芳香族化合物和含氧化合物;升高温度、加入水蒸气或催化剂均能降低焦油产量,使焦油芳香性增大;加入水蒸气更有利于焦油重整;催化剂可使焦油组分趋于单一化,3种催化剂的焦油裂解性能依次为Fe2O3CaOMgO。     

焦化废水处理中的脱氮过程

叙述了焦化生产过程中由于装煤时一般采用喷氨工艺,导致废水中的NH3-N非常高,而又不进行硝化、反硝化的处理的情况,指出,为保证处理后出水水质能够达到回用于熄焦的标准,避免腐蚀接焦车,脱氮是非常必要的.     

Study on solid waste pyrolysis coke catalyst for catalytic cracking of coal tar

Low value solid waste pyrolysis coke was used as a catalyst to catalytically crack gas-phase tar to improve tar yield and gas production. Pyrolysis coke with different pyrolysis final temperature and pyrolysis time were prepared, the effect of tar cracking products was studied, and the optimal pyrolysis coke were screened. The pyrolysis coke catalyst was characterized by BET, FTIR, SEM. The results show that the optimal preparation final temperature of pyrolysis coke is 750 °C, and the optimal preparation pyrolysis time is 2 h. Compared with the pyrolysis of raw coal, the tar cracking rate increased by 9.3%, after added the pyrolysis coke catalyst, the gas increased by 23.2%, and the light component increased to 36.6%. And the OH, C–N and C–O–C functional groups present on coke are the factors that affect the catalytic cracking.     

Roles of AAEMs in catalytic reforming of biomass pyrolysis tar and coke accumulation characteristics over biochar surface for H2 production

Coke formation is a significant challenge in catalytic tar reforming. AAEMs are essential in the conversion and decomposition of tar catalyzed by biochar. In this paper, four biochar catalysts with different K and Ca contents were prepared by acid washing and loading, and the coke accumulation characteristics in catalytic tar reforming at 650 °C were investigated using a single-stage reaction system. The gas-liquid-solid products were characterized by GC-MS, Raman, N₂ adsorption, FTIR and TG. The results suggest that K-loaded biochar has a maximum tar reforming capacity of 94.9%, while H-form biochar has a tar removal efficiency of only 27.8%. The micropore area in biochar is considerably reduced and the average pore size is increased after coke deposition. While K-loaded biochar retains the highest micropore area, it also exhibits a smaller increase in average pore size. The loading of K/Ca affects the growth structure of the coke, resulting in an increased number of O-containing structures in it. The coke on the Raw biochar surface is mainly small aromatic ring structures and aliphatic structures, thus increasing the intensity of the vibrational peaks corresponding to aromatic = C–H and aliphatic C–H on it. The coke on K-loaded biochar has a large proportion of aliphatic structures, which also contributes to the reduced graphitization of it after reforming. The AAEMs-free biochar surface preferentially removes tar components carrying O-containing groups. K-loaded biochar preferentially catalyzes the reforming of mono-aromatic ring components in tar. Ca-loaded biochar preferentially removes the mono-aromatic ring components, while being less selective for the removal of tar components containing hydroxyl groups and polyaromatic ring components. The loading of K/Ca promotes the dehydrogenation of the tar fraction during reforming, while only K catalyzes the deoxygenation of tar components. H-form biochar has no appreciable catalytic activity on CH₄ cracking. AAEMs have a catalytic activity on CH₄ cracking. K is particularly effective in improving tar conversion and hydrogen production of biochar.     

焦炉煤气的余热利用

通过对焦炉煤气初冷过程的理论分析，指出焦化厂现行的单靠循环氨水喷洒集气管加初冷器的冷却过程中，能量利用的不合理，着重介绍了一项值得推广的煤气初冷余热利用系统。     

Steam co-gasification of Japanese cedarwood and its commercial biochar for hydrogen-rich gas production

In this study, steam gasification and co-gasification of Japanese cedarwood and its commercial biochar were performed in a lab-scale fixed-bed reactor to investigate the feasibility for producing H₂-rich syngas. Ultimate analysis, proximate analysis, Brunauer-Emmett-Teller (BET) surface area analysis, and scanning electron microscopy (SEM) were conducted to understand the changes caused by the carbonization process. The effects of gasification temperature and steam flow rate on gas production yield from the steam gasification of the individual samples were investigated at first, which showed larger gas production yield and less tar yield for the steam gasification of the commercial biochar than that of raw cedarwood, indicating that the commercial biochar obtained from the carbonization process was more beneficial for the gasification. The co-gasification of raw Japanese cedarwood and its commercial biochar with different mixing ratios was conducted at different reaction temperatures. The synergistic effect was obviously observed. Especially, the commercial biochar with the highly porous structure and high content of alkali and alkaline earth metal (AAEM) species might provide the catalytic effect on cracking and reforming of tar derived from the raw cedarwood, resulting in a larger H₂ yield. However, the catalytic effect and gasification reactivity of biochar would decrease by increasing the amount of raw-cedarwood in the blends due to the coke deposition on the surface of biochar.     

Fuel saving, carbon dioxide emission avoidance, and syngas production by tri-reforming of flue gases from coal- and gas-fired power stations, and by the carbothermic reduction of iron oxide

Flue gases from coal, gas, or oil-fired power stations, as well as from several heavy industries, such as the production of iron, lime and cement, are major anthropogenic sources of global CO₂ emissions. The newly proposed process for syngas production based on the tri-reforming of such flue gases with natural gas could be an important route for CO₂ emission avoidance. In addition, by combining the carbothermic reduction of iron oxide with the partial oxidation of the carbon source, an overall thermoneutral process can be designed for the co-production of iron and syngas rich in CO. Water-gas shift (WGS) of CO to H₂ enables the production of useful syngas. The reaction process heat, or the conditions for thermoneutrality, are derived by thermochemical equilibrium calculations. The thermodynamic constraints are determined for the production of syngas suitable for methanol, hydrogen, or ammonia synthesis. The environmental and economic consequences are assessed for large-scale commercial production of these chemical commodities. Preliminary evaluations with natural gas, coke, or coal as carbon source indicate that such combined processes should be economically competitive, as well as promising significant fuel saving and CO₂ emission avoidance. The production of ammonia in the above processes seems particularly attractive, as it consumes the nitrogen in the flue gases.     

Energy and environmental analysis of an entire coke production plant using ECLIPSE

In the present work the sequential code ECLIPSE is used to perform an energy analysis of an entire industrial process—a coke production plant—aiming its characterization and optimization in terms of energy requirements and environmental impact. The code is validated by comparing its results against existing experimental data acquired at the above‐referred plant, for the present operating conditions. Agreement is observed to be rather good, as the maximum relative errors between the ECLIPSE predictions and the actual values are 9.2, 9.7 and 8.7 per cent, respectively, for mass flows, temperatures and pressures. Moreover, those errors occur only once and at different streams, the vast majority of the relative errors for the remaining streams being below 1.0 per cent. In order to optimize the process both as far as energy and environmental aspects are concerned, alternative or new unit operations are suggested and are included in the production flow sheet or added to it and the entire new processes are simulated. More specifically, the better sealing of the coke ovens doors eliminating 80 per cent of the volatiles escape, the recovery of the lost sensible heat in the coke extinction operation and the restart of the 10 non‐productive coke ovens would yield remarkable energy savings—losses would reduce from 46 440 to 9260 kW, apart from the environmental benefits emerging from the elimination of the volatiles escape to the atmosphere. In addition, for the coke gas cleansing sub‐process, the substitution of the stripping process in the column distillation by a separation process, making recourse to a reverse osmosis installation, together with the operation setting of the ammonium destruction oven at a more convenient temperature, would allow both for energy savings of 66 per cent and a substantial reduction in both gaseous and liquid emissions, namely naphthalene, ammonia, nitric oxides and sulphur oxides. The improvements attained are noticeable and encouraging. Therefore, ECLIPSE proved to be an adequate tool for global industrial processes simulation, analysis and optimization, in spite of some limitations exhibited by the code in simulating detailed complex physical phenomena, such as combustion or coal distillation. Copyright © 2001 John Wiley & Sons, Ltd.     

Experimental study on catalytic effect of biomass pyrolysis volatile over nickel catalyst supported by waste iron slag

The study aims to analyze catalytic tar destruction, evaluate the activity of the Ni‐based catalyst supported by waste iron slag, and obtain clean pyrolysis syngas. The effects of different nickel loadings, catalytic temperatures, and catalyst calcination temperatures on volatile were investigated in order to determine the optimal process condition. The analysis results showed that the iron slag Ni‐based catalyst had a relatively low specific surface area. However, it showed an excellent resistance performance to the coke deposition and displayed the high tar removal ability. Moreover, the tar conversion and the yield of syngas were significantly affected by nickel loadings. When the nickel loading reached 3%, the tar dew point was decreased by nearly 100 °C and the tar conversion reached 94.84%. The favorable reaction temperature was about 800 °C based on the consideration of energy consumption and the catalytic performance. Calcination temperature affected tar yield and syngas yield. The application of iron slag in nickel catalyst realized the reutilization of waste materials, indicating significant practical values. Copyright © 2017 John Wiley & Sons, Ltd.     

Evolution characteristics of different types of coke deposition during catalytic removal of biomass tar

The evolutions of different types of coke deposition, including amorphous carbon, carbon networks (CNWs) and carbon nanotubes (CNTs), were clarified on Ni-based catalyst during catalytic cracking and reforming of biomass tar. Different from the changing of total coke, the amount of amorphous carbon gradually increased at the decreasing rate, while the amount of graphite carbon (CNWs and CNTs) firstly increased and then decreased after 60min reactions. The formation of amorphous carbon was prior to that of graphite carbon, and it was proved that a part of amorphous carbon converted to graphite carbon. After the 60min reaction, the proportion of graphite carbon and graphitization degree of coke decreased. The graphite carbon underwent the aging process in which the graphite structure would be destroyed to amorphous carbon. In cracking reaction, CNWs was the main type of graphite carbon which encapsulated the Ni particles with graphitic layers. After the addition of steam, the toluene conversion and coke amount remarkably increased in reforming reaction. Plenty of CNTs grew on the surface of catalysts and the amount of CNTs reached the maximum of about 200mg/g-cata at 60min. These research results are important for understanding the formation mechanism of coke and optimization the produced CNTs.     

Numerical simulation on biomass-pyrolysis and thermal cracking of condensable volatile component

We studied the physical and chemical properties of the condensable volatiles of biomass pyrolysis products. We redefine the liquid product and divide the condensable volatiles into two categories, biomass oil and tar, the latter of which comes from the secondary pyrolysis or cracking reaction of the former. We further establish a kinetic model of biomass pyrolysis and secondary cracking. The chemical reaction kinetics equation and heat transfer equation are coupled to simulate the biomass pyrolysis process. For biomass solid particles, the model not only considers the initial reaction of biomass and secondary cleavage reaction of condensable gas, but also introduces a reaction mode in which biomass oil is converted into tar. When the pyrolysis temperature is below 500 °C, the pyrolysis products are essentially biomass oil. However, when the pyrolysis temperature exceeds 500 °C, the biomass oil gradually converts into tar. The model also considers characteristics of the reaction medium (porosity, intrinsic permeability, thermal conductivity) and the unsteady gas phase process based on Darcy's law of velocity and pressure, heat convection, diffusion, and radiation transfer. We analyze the relationships among the internal temperature of the particles, particle size and position, mass fraction of the reactants and products, the gas mixture, the production share of tar and biomass oil, and the relationship between gas pressure and time. The results show that the effects of the secondary cracking reaction and internal convective flow in the biomass pyrolysis process are coupled because the flow field in the porous medium determines the volatile residence time and thus species that affect the secondary cracking reaction. The rate of volatile formation in the initial and secondary cracking reactions affects the pressure gradient and gas diffusion. Additionally, the endothermic effect influences the temperature field of the pyrolysis reaction but has no apparent effect on small particles whose chemical reaction is the control mechanism. For large particles, heat transfer inside the particles is the diffusion control mechanism and the chemical reaction on the particle surface is the speed control mechanism. Two peaks are observed in the pyrolysis gas mass proportion curve, which result from the consumption of biomass oil and tar as they flow toward hot surfaces. The first peak is the decomposition of biomass oil into non-condensable volatile matter and tar, and the second peak is the further cracking of tar into gas and coke at high temperature.