摘要
以煤为原料的甲醇产品中普遍存在着因乙醇质量分数高而影响产品质量等级的问题。通过流程模拟软件分析其关键的影响因素,可以为改善产品质量的研究指明方向。文中以某甲醇厂精馏工段现场工艺流程为依据,建立了甲醇四塔精馏过程的计算机模拟模型,综合考虑气液二相逸度计算方法的差异,模拟时采用的物性方法为Wilson-RK。模拟结果与现场采集数据误差较小,说明该模型与实际工艺吻合良好。分别从合成与精馏的角度分析了粗甲醇中乙醇质量分数高的原因。运用软件的灵敏度分析功能,研究了预塔萃取水量、加压塔和常压塔的进料位置以及常压塔侧线采出位置对产品中乙醇质量分数的影响。分析结果表明:在现有条件下控制粗甲醇中乙醇质量分数低于4×10-4时,可制得约为一半产量的双A级精甲醇,同时依据温度分布选择常压塔最优侧线采出位置,可有效地降低产品中乙醇的质量分数。
The quality level of coal-based methanol product is often influenced greatly by the high mass fraction of ethanol. The research direction for improving the product quality can be shown by analyzing the key factors with the process simulation software. On the basis of the flowsheet of the methanol rectifying section on site, a four-tower simulation model was built for methanol distillation process, considering the difference for the fugacity computation of vapor and gas phase, the suitable property method for simulation was Wilson-RK. The errors between the simulation results and collected data are small, indicating that this simulation model is identical with the real producing process. The reasons why a high ethanol mass fraction in the crude methanol were analyzed from two aspects. By using the sensitivity function of the software, the effects of the extraction water, feed stage of the pressurized and atmospheric column and side-draw stage of the atmospheric column on the ethanol mass fraction in the products were studied. The simulation results indicate that controlling the ethanol mass fraction in the crude methanol lower then 4 × 10-4 can get almost half yield of double A grade methanol under the current condition. Choosing the optimal side-draw stage of the atmospheric column based on the temperature distribution is an effective way for lowering ethanol mass fraction.
出处
《化学工程》
CAS
CSCD
北大核心
2014年第4期68-72,共5页
Chemical Engineering(China)
关键词
甲醇
乙醇
流程模拟
质量控制
methanol
ethanol
process simulation
quality control
