压力对原油裂解成气影响的对比模拟实验

Comparative simulation experiments regarding influence of pressure on crude oil cracking into gas

通过在不同的实验体系(常压和20 MPa)进行的原油裂解成气模拟实验,对原油裂解成气过程和裂解气产率进行研究。结果表明:低速率长时升温相对高速率短时升温对原油裂解成气更有利;压力对原油裂解有抑制或延迟作用,压力条件下原油初始裂解时间滞后,原油裂解温度门限较高;压力可能抑制了重烃气C2-5向甲烷的二次裂解,20MPa下在高温阶(600～650℃)较常压有显著高的C2-5产率和低的干燥系数;加压环境下水参与了原油裂解反应,加压水体环境下原油转化率降低而总产气率、重烃气C2-5产率和二氧化碳产率升高;二氧化碳和重烃气C2-5质量产率变化规律和形成机制比较接近;总裂解气主生气期在425～650℃,对应Ro约为1.5%～2.4%。

Two different pressure systems （normal pressure system and 20 MPa pressure system） were used to conduct the com-parative simulation experiments in order to study the effect of pressure on the oil cracking into gas and the gas production. The results show that low heating rate in long time is more favorable for oil cracking than high heating rate in short time. Pressure has suppression on the oil cracking into gas. The initial oil cracking is retarded and the temperature threshold for oil cracking is higher at high pressure. The 20 MPa pressure system shows much higher C2-5 production rate and lower dry coefficient compared with normal pressure system, which indicates that the heavy hydrocarbon gas C2-5 cracking into methane at high temperature （600-650 ℃ ） was inhibited by pressure. Water is likely to involve in the oil cracking reaction in the overpressure system, re-flected by the lower oil transformation rate and higher production rate of carbon dioxide, C2-5 gas and total cracking gas in the o-verpressured-system with more water. The formation mechanisms of the carbon dioxide and heavy hydrocarbon gas C2-5 are close indicated by the similar changes of production rates during the crude oil cracking into gas. The main gas genaration period for total cracking gas is 425-650 ℃ in the experiment, and corresponding Ro is 1.5%-2. 4%.