Abstract:

The chemical reaction engineering nowadays is facing the new challenge from the degraded feedstocks of heavy fossil resources and low-value intermediate chemical products. Thermal plasma technique operated at extreme conditions (e.g., ultra-high temperature) is proposed as a potential means to realize the clean and efficient conversion of materials that are difficult to be handled using the conventional technologies. This work aims to study the pyrolysis performances of representative coal, coal tar and asphaltene materials in thermal plasmas. Experimental investigations were carried out on a lab-scale device to evaluate the pyrolysis characteristics of the feedstocks. The results showed that higher conversion and acetylene yield than coal can be achieved by using coal tar and asphaltene as the feeds. A model to describe the material and energy balances was established based on thermodynamics and the thermal effects in the thermal plasma process. The simulations on 2 MW pilot-plant scales were performed to compare the pyrolysis performances of these feedstocks, and the material and energy flows for these system operated under the same conditions were presented. Furthermore, analysis of pyrolysis with mixed materials showed an improved performance when adding coal tar or asphaltene into the coal pyrolysis system. It is anticipated that this work would provide scientific basis for feedstock selection and feedstock blending in the applications of thermal plasma pyrolysis.

Key words: multiphase reactor, plasma, thermodynamics, hydrocarbons, acetylene

摘要：

针对化石资源劣质化和大宗低价值化工中间产品的反应工程新问题,提出利用热等离子体超高温特性实现极端条件下难利用原料的高效清洁转化,重点探讨并比较了煤化工中的原煤、煤焦油和石油化工中的沥青质的热等离子体裂解特性。通过热等离子体裂解实验室小试装置考察了3种典型原料的裂解行为,结果表明,煤焦油和沥青质具有高于煤的转化率和乙炔收率;建立了基于热力学的热等离子体裂解反应过程的能量平衡分析方法,模拟计算了不同操作条件下各原料在兆瓦级中试装置上的裂解结果,给出了相同等离子体能量注入的条件下不同原料裂解过程的物流和能流关系;并进一步模拟分析了原料间混合裂解的混料配比对裂解气的影响,为热等离子体裂解过程的工业原料筛选和原料混合裂解提供了科学依据。

关键词: 多相反应器, 热等离子体, 热力学, 碳氢化合物, 乙炔