The Units Integration Simulation Of Gasification And Water Gas Shift In The System Of Coal (Coke) Water Slurry Gasification For Hydrogen

The effects of integration between gasification unit and water gas shift unit on the system of coal (coke) water slurry gasification for hydrogen are investigated. In order to evaluate quantitatively the effects of syngas cooling ways on the entrained-flow bed gasification for hydrogen system, two schemes of gasification for hydrogen are developed in this work, which are total quench+high water/dry gas(W/G) and radiant syngas cooler+quench+low W/G, named by case1and case2, respectively. The two processes are simulated by using Aspen Plus. The results show that the energy conversion efficiency of case1and case2are the same, which are74.16%and74.14%, respectively. The exergy efficiency of case2is higher than that of the case1, which are61.88%and61.07%, respectively. The proportion of high quality steam produced in the case2is higher and the quantity of high quality steam is larger than that of the case1. The system profit of the case2is better than that of the case1. Thus, the case2is better than the case1and is more suitable for petcoke gasification for hydrogen taking the gasification performance, energy utilization and system performance yield analysis into account.In order to utilize the low-grade energy properly, obtain the purpose of energy cascade utilization and improve performance of the coal water slurry gasification system, the heat integration between water gas shift unit and gasification unit is put forward in this work. The process utilizes low-pressure steam in the water gas shift unit to preheat the feedstock(coal water slurry and oxygen) in the gasification unit. The feasibility of heat integration scheme is analyzed in this work. The effects of feedstock temperature change on the system performance are investigated. The results show that the specific coal consumption and the specific oxygen consumption decrease by2.7%and6.5%, respectively, as the feedstock is preheated up to the temperature of150. The energy conversion efficiency of HIS and NHIS are nearly the same. The exergy efficiency of HIS (62.66%) is better than that of NHIS (62.02%). The carbon dioxide emission reduction rate of the heat-integration scheme is2.7%compared with the non-heat-integration scheme. It is economical to conduct the heat integration between the gasification unit and the water gas shift unit.