Abstract:

The research conducted the experiments for N₂/CH₄ separation using the vacuum pressure swing adsorption (VPSA) process based on the two-bed experimental set-up and the laboratory-made activated carbon as adsorbent. The mathematical models were built in gPROMS and the accuracy of models was verified by comparison of simulations and experiments. The simulation results showed that the two-bed VPSA process can obtain a rich-methane product with 80% methane purity and 83% methane recovery. But in the actual operation, disturbances of system state are inevitable and influenced the technical indexes such as purity. The studies of disturbance and control are performed and the controller is designed for the VPSA system. The results demonstrate by introducing the controller, the purity of product can be promised under various disturbances.

Key words: nitrogen/methane, VPSA, simulation, activated carbon, control

摘要：

采用实验室自制的活性炭为吸附剂，进行了真空变压吸附（VPSA）分离氮气/甲烷的实验、模拟和控制研究。建立了一套双塔VPSA实验装置，并将其数学模型建立在gPROMS软件中，通过改变进料气流量做多组对比实验，通过模拟数据和实验数据的对比，验证了数学模型的准确性。通过双塔VPSA的模拟调试，可以将甲烷的纯度由30%提升到80%，同时保证83%的回收率。随后，针对实际生产中不可避免的状态干扰因素，选取了3种常见的扰动状况，以产品气纯度快速回归至80%为控制目标，根据本文所采用的VPSA系统设计了PID控制器，进行了模拟和控制的研究。研究结果表明，引入PID控制器可以使纯度受到扰动影响时较快速地回归至合格纯度，同时保证装置较为稳定的运行。

关键词: 氮气/甲烷, VPSA, 模拟, 活性炭, 控制