Hydrogen production by steam-gasification of petroleum coke using concentrated solar power—I. Thermodynamic and kinetic analyses
- 作者：Trommer ; D. ; Noembrini ; F. ; Fasciana ; M. ; Rodriguez ; D. ; Morales ; A. ; Romero ; M. ; Steinfeld ; A.
- 关键词：Petroleum ; Coke ; Hydrogen ; Syngas ; Solar ; Gasification ; Fluidized bed
- 刊名：International Journal of Hydrogen Energy
- 出版年：2005
- 期刊代码：42_03603199
- 类别：ch
- 出版时间：May, 2005
- 卷：30
- 期：6
- 页码：605-618
- 文件大小：540 K
摘要
The steam-gasification of petroleum coke using concentrated solar radiation as the source of high-temperature process heat is proposed as a viable transition path towards solar hydrogen production. The advantages are three-fold: (1) the calorific value of the feedstock is upgraded; (2) the gaseous products are not contaminated by the byproducts of combustion; and (3) the discharge of pollutants to the environment is avoided. The thermodynamics and kinetics of the pertinent reactions are analyzed for two types of petroleum coke: Flexicoke and Petrozuata Delayed coke. The net process is endothermic by about 50%of the feedstock's LHV, and proceeds at above 1300K to produce, in equilibrium, an equimolar mixture of Formula Not Shown and CO. A Second-Law analysis on the processing of this syngas to Formula Not Shown (by water–gas shift followed by Formula Not Shown separation) for power generation in a fuel cell indicates the possibility of doubling the specific electrical output and, consequently, halving the specific Formula Not Shown emissions, vis-à-vis conventional coke-fired power plants. Kinetic rate laws are formulated based on elementary reaction mechanisms describing reversible adsorption/desorption processes and irreversible surface chemistry. The kinetic parameters and their Arrhenius-type temperature dependence are experimentally determined using a quartz tubular reactor containing a fluidized bed of petroleum coke in steam and directly exposed to concentrated thermal radiation. Syngas containing approximately an equimolar mixture of Formula Not Shown and CO and with a relative Formula Not Shown content of less than 5%was produced at above 1350 and 1550K for Flexicoke and Petrozuata Delayed coke, respectively.