生物质焦与煤共气化特性研究

本文利用非等温热重分析法研究了生物质焦与煤的共气化特性,探讨了生物质焦与煤共气化反应特征温度的变化情况,并分别运用Doyle和Coats-Redfern近似函数计算了反应动力学参数.采用Doyle法计算时,相关系数R2值比Coats-Redfern法更大,因此Doyle法计算结果更合理.采用Doyle法计算出：生物质焦的气化反应活化能为134.97 kJ/mol,烟煤和无烟煤分别是197.85 kJ/mol和171.36 kJ/mol.随着无烟煤、烟煤中生物质焦掺混的比例增加,反应活化能不断下降.研究结果表明：生物质焦可以促进两种煤的气化反应,降低煤的最终反应温度和气化反应活化能.     

一种新型共气化工艺的开发

As one of promising clean coal technologies used to reduce pollutant emission and CO2 discharge, cogasification has been extensively investigated. In this paper, a new co-gasification technology using coal and natural gas was developed. The distinct advantages of this technology are the excellent fuel flexibility and the availability to establish the gasifler by reconstructing the blast furnace or similar shaft furnace. Based on the concept of the new co-gasification technology, lab-scale experiments and modeling study were carried out. The obtained results indicate that gasification is undertaken at ideal thermodynamic environment where quasi-equilibrium could be reached without catalysts. The modeling results are in agreement with experimental data, demonstrating the validity of the model and that Aspen Plus is a useful tool for the analysis of the co-gasification process. Furthermore,the effect of major operation parameters, including oxygen flow rate and steam flow rate, on co-gasification process was investigated using the developed model.     

水煤浆与天然气共气化热力学模拟

为了降低生产成本,减少CO_2排放,实现n(H_2)/n(CO)可调,将水煤浆与天然气进行联合转化。从热力学角度对共气化过程各反应的竞争能力进行了分析。利用Aspen Plus软件对该过程进行了模拟,分析了氧气进料流量、天然气进料流量对气化炉出口温度、气体摩尔组成、合成气摩尔分数、n(H_2)/n(CO)的影响。计算了多种不同进料流量下的出口参数,通过对这些数据进行筛选,得到气化室出口温度在1 340~1 360℃之间,n(H_2)/n(CO)大于1.15,合成气摩尔分数大于0.72时的天然气和氧气的进料流量。     

生物质与煤（共）热解/气化过程中挥发分-半焦交互作用研究与进展

生物质和煤协同热化学转化是实现非化石能源和化石能源耦合高效利用的技术手段,对实现“双碳”目标具有重要现实意义。基于生物质等含碳燃料高挥发分组成和富氧特性,热化学转化过程不可避免地发生挥发分-半焦交互作用并影响原料性质和设备过程参数。综述了生物质与煤（共）热解/气化过程中挥发分-半焦交互作用的研究进展,总结了交互作用对挥发分的催化裂解规律、对半焦结构与性质的影响及生物质和煤协同热化学转化下的解耦研究思路三方面具体内容。针对目前挥发分-半焦交互作用机制解析过程所采用的研究方法及思路,提出了新的见解并对未来交互作用的重点研究方向进行了展望,以期为进一步认识交互作用的物理化学本质提供理论指导。     

煤焦与水蒸气及CO2共气化反应性研究

采用常压热天平实验装置,在温度为1 173～1 323 K条件下,研究了3种煤焦与水蒸气、CO₂及二者不同配比混合气体的气化特性.结果表明：气化反应温度越高,煤焦的气化反应性越好;气化剂配比中水蒸气的含量越高,煤焦的反应性越好.3种煤焦与水蒸气及CO₂共气化反应性顺序为：神东>宝一>王坡;同一气化剂配比下,3种煤焦的平均比气化速率随温度的升高而增大,同一气化温度下,3种煤焦的平均比气化速率随气化剂中水蒸气含量的增加而增大;3种煤焦在与水蒸气及CO₂混合气体共气化过程中表现出的交互作用不同.     

Crystallization and viscosity-temperature characteristics during co-gasification of industrial sludge and coal

Co-gasification of industrial sludge (IS) and coal was an effective approach to achieve harmless and sustainable utilization of IS. The long-term and stable operation of a co-gasification largely depends on fluidity of coal-ash slag. Herein, the effects of IS addition on the crystallization and viscosity of Shuangmazao (SMZ) coal were investigated by means of high temperature stage coupled with an optical microscope (HTSOM), a scanning electron microscopy coupled with an energy dispersive X-ray spectrometry (SEM-EDS), X-ray diffraction (XRD), a Fourier transform infrared spectrometer (FTIR), and FactSage software. The results showed that when the proportion of IS was less than 60%, with the addition of IS, the slag existed in an amorphous form. This was due to the high content of SiO₂ and Al₂O₃ in SMZ ash and blended ash, which had a high glass-forming ability (GFA). The slag formed at a high temperature had a higher polymerization degree and viscosity, which led to a decrease in the migration ability between ions, and ultimately made the slag difficult to crystallize during the cooling. When the proportion of IS was higher than 60%, the addition of IS increased the CaO and FeO content in the system. As network modifiers, CaO and FeO could provide O²⁻ at a high temperature, which reacted with silicate network structure and continuously destroyed the complexity of network structure, thus reducing the polymerization degree and viscosity of slag. At this time, the migration ability between ions was enhanced, and needle-shaped/rod-shaped crystals were precipitated during the cooling process. Finally, the viscosity calculated by simulation and Einstein-Roscoe empirical formula demonstrated that the addition of IS could significantly improve the fluidity of coal ash and meet the requirements of the liquid slag-tapping gasifier. The purpose of this work was to provide theoretical support for slag flow mechanisms during the gasifier slagging-tapping process and the resource treatment of industrial solid waste.     

煤与重质油共气化可行性研究

分析了煤与重质油共气化过程和热力学特点,应用流程模拟软件Aspen Plus对焦炭和渣油系统进行了热力学能量和物料平衡计算,从热力学角度进行了可行性研究。结果表明,煤与重质油共气化技术可以制备低碳烯烃并联产合成气,低碳烯烃(C2H4 C3H6)含量大于15%,合成气(H2 CO)含量大于60%,CO2含量小于1.5%,且能有效地解决重质油裂解造成的结焦问题。     

恒温下生物质与煤共气化特性研究

煤和生物质进行共气化不仅拥有煤和生物质单独气化的优点,还能够消除弥补煤与生物质分别气化时的缺点。在自行搭建的热重分析仪上进行了煤与生物质的共气化实验研究,研究了焦样粒径、CO2流量对气化反应的影响。研究了煤与生物质单独气化的特性,结果显示生物质的气化活性要高于煤;研究了煤与生物质共气化特性,发现在气化反应前期存在一定的抑制作用,气化反应后期存在协同作用。     

Hydrothermal co-gasification of sorghum biomass and çan lignite in mild conditions: An optimization study for high yield hydrogen production

In this study, response surface methodology (RSM) combined with a 3–factor and 3–level Box–Behnken design (BBD) was performed to obtain high yield hydrogen production from hydrothermal co–gasification of sorghum biomass and low rank Çan lignite in a batch type reactor at 500 °C. The individual and the combined effects of the process parameters of coal amount (%) of the coal/biomass mixtures, initial water volume (mL) of the reactor and amount of the coal/biomass mixtures (kg) on system pressure, total gas yield, hydrogen production and product distribution were determined. Water volume directly affected the system pressure and the reaction medium was supercritical water medium above 48.2 mL with a pressure of 22.06 MPa. The highest values of both total gas volume and hydrogen gas volume were reached by gasification of 5.0 g of feedstock. It has been observed that total gas volume and hydrogen volume were directly affected by the water volume in the reactor and the coal ratio of the coal-biomass mixtures. The highest total gas and hydrogen volumes can be achieved under the conditions where the higher levels of water volume of the reactor and lower levels of coal percentage of the coal/biomass mixture were combined. Optimum conditions for maximum hydrogen production with 5.0 g of coal/biomass mixture were determined with numerical optimization as coal percentage of 25.6% and initial water volume of 68.5 mL. By combining the impregnated K₂CO₃ (3%, (w/w)) and CaO catalysts an excellent hydrogen selectivity was achieved. The hydrogen selectivity was drastically increased from 32.0% to 70.8% by capturing more than 99% of CO₂ with a H₂/CO₂ mol ratio of 88.5.     

掺混比例对生物质和煤流化床共气化特性影响的试验研究

采用新型床料在鼓泡流化床中进行了2种典型的木本和草本生物质与烟煤的空气-水蒸气气化试验,研究了生物质掺混比例对燃气组分和热值、气化效率及碳转化率等参数的影响规律.结果表明:当松木屑的掺混比例从0%增大到100%时,H2和CO的体积含量分别增加了4.6%和4.4%,CO2的体积含量减少了3%,CH4和CnHm的含量也有所增加;当稻秸的掺混比例从0%增大到100%时,CO的体积含量先从25.8%上升至27.5%,再下降至25.3%,其他燃气组分的变化趋势与松木屑和煤气化的相类似;随着生物质掺混比例的增加,2种生物质和煤共气化的气化效率和碳转化率均有所提高,且在共气化过程中存在协同效应.