Abstract:

In view of the poor deoxygenation and low safety for CH₄/N₂/O₂ mixture a two-bed vacuum pressure swing adsorption (VPSA) process for separating 25% CH₄/59% N₂/16% O₂ mixture was developed by numerical simulation and experiment based on the laboratory-made activated carbon adsorbent. The VPSA mathematical models were validated by comparing the influences of feed and replacement flowrates variations on experimental and simulative results, respectively. On the basis, safety analysis of entire VPSA process was performed systematically to seek for the steps in presence of potential safety hazard. On the basis of analysis, a more safe VPSA process was proposed to achieve safe separation operations. The research results showed that the two-bed VPSA process can obtain a rich-methane product with 51.36% methane purity and 85.65% recovery. The adsorption, pressure-equalization and pressurization were the dominating steps in the presence of potential safety hazard, which can be sought for a solution to realize the safe operations of VPSA process by feed gas inserting.

Key words: CH₄/N₂/O₂, vacuum pressure swing adsorption, simulation and experiment, safety analysis

摘要：

针对CH₄/N₂/O₂混合物脱氧效果差以及安全性低等问题，采用实验室自制活性炭为吸附剂，通过数值模拟和实验进行了双塔真空变压吸附（VPSA）分离25% CH₄/59% N₂/16% O₂混合物的工艺研究。通过考察进料流量和置换流量对甲烷产品纯度和回收率的影响，实验验证了数值模型的准确性。在模拟和实验的基础上，对VPSA工艺全流程进行了系统的安全性分析，并针对存在安全隐患的过程，提出一种更为安全的VPSA工艺流程。研究结果表明，通过双塔VPSA可以获得甲烷纯度为51.36%的产品气，甲烷回收率可达85.65%，存在安全隐患的过程主要集中在吸附、均压和终升压步骤，通过原料气的惰化过程，可以实现VPSA工艺的安全操作。

关键词: CH₄/N₂/O₂, 真空变压吸附, 模拟和实验, 安全性分析