气流床煤气化高位热能分级回收技术研究

Study on Staged Recovery Technology of High Level Heat Energy from Entrained Flow Coal Gasification

针对气流床煤气化高温气化产物的显热回收系统进行了研究,利用系统能量平衡和3D数值模拟方法,以日处理煤2000 t级干煤粉下行式气化炉为例,针对气化后全废锅系统进行了物料平衡、热平衡和辐射废锅结构优化设计。研究结果表明:下行式干煤粉气化炉的气化后产物与水煤浆气化产物存在明显差异,干煤粉气化合成气辐射传热系数较低,需要采用低温合成气激冷进行快速降温,可有效达到熔渣颗粒的快速降温凝结,激冷气量约为气化炉产出气体总量的28%;针对全废锅系统,该当量气化炉的废锅系统可副产100 t以上中高压过热蒸汽以及20 t以上中低压饱和蒸汽,可以使气化系统的能量利用效率提高10个百分点以上。

In this paper,the sensible heat recovery system of high-temperature gasification products of entrained flow coal gasification was studied.Using the system energy balance and 3D numerical simulation method,the mass balance,heat balance and radiative syngas cooler structure optimization design were carried out for the whole heat recovery system of a dry pulverized coal gasifier with daily capacity of 2000 tons.The results show that there are obvious differences between the gasification products in the dry pulverized coal gasifier and the coal water slurry gasification products.The radiative heat transfer coefficient of dry pulverized coal gasification gas is low,so it is necessary to use low temperature synthesis gas to quench the high temperature syngas and molten slag particle,which can effectively achieve the rapid temperature reduction and condensation of molten slag particles,and the quenching gas consumption is about 28%of the total syngas produced by the gasifier.For the whole heat recovery system,this gasifier can produce more than 100 tons of medium and high pressure superheated steam and more than 20 tons of medium and low pressure saturated steam,which can increase the energy utilization efficiency of the gasification system by more than 10%.