CIESC Journal ›› 2023, Vol. 74 ›› Issue (2): 784-795.DOI: 10.11949/0438-1157.20221488

• Separation engineering • Previous Articles     Next Articles

Modeling and simulation of CH4/N2 separation process with two absorption-adsorption columns using ZIF-8 slurry

Xiaowan PENG(), Xiaonan GUO, Chun DENG(), Bei LIU, Changyu SUN, Guangjin CHEN   

  1. State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum, Beijing 102249, China
  • Received:2022-11-15 Revised:2023-01-14 Online:2023-03-21 Published:2023-02-05
  • Contact: Chun DENG

ZIF-8浆液法分离CH4/N2的双吸收-吸附塔工艺流程建模与模拟

彭晓婉(), 郭笑楠, 邓春(), 刘蓓, 孙长宇, 陈光进   

  1. 重质油国家重点实验室,中国石油大学(北京)化学工程与环境学院,北京 102249
  • 通讯作者: 邓春
  • 作者简介:彭晓婉(1995—),女,博士研究生,1836160461@qq.com
  • 基金资助:
    国家自然科学基金项目(22278429)

Abstract:

Due to the unique flowability of ZIF-8 slurry, the traditional absorption-desorption process can be used for reference to realize the multi-stage continuous high-efficiency enrichment of methane in coalbed methane. In this paper, based on the single absorption-adsorption column process, a new process with two absorption-adsorption columns operated at high and low pressures is proposed aiming to reduce the energy consumption. The whole process modeling and simulation of the process was conducted. Using the equilibrium stage method, the mathematical model of each mass transfer unit in the process was established, including absorption-adsorption column, flash tank, and desorption column. Moreover, sensitivity analysis was carried out to explore the effects of equilibrium stages, feed stage, gas-slurry ratio, and desorption pressure on process performance, such as methane concentration in product gas and recovery ratio. The simulation results show that the recovery rate is 90.25% when the methane concentration reaches 90.13%(mol). In addition, the energy consumption per unit feed is 0.445 kW·h·m-3 (feed gas), which is lower than the energy consumption of the process with a single column (0.510 kW·h·m-3). The results show that compared with the single-column process, the improved double-column process can further reduce energy consumption while fulfilling the requirements of methane purity and recovery ratio.

Key words: ZIF-8, coalbed methane, methane, nitrogen, adsorption

摘要:

由于ZIF-8浆液独特的可流动性,可以借鉴传统的吸收-解吸工艺,实现煤层气中甲烷的多级连续高效富集。在单吸收-吸附塔工艺的基础上,为了进一步降低能耗,提出了高低压双吸收-吸附塔新型分离工艺,并对该工艺进行了全流程建模及模拟。采用平衡级法,建立了工艺流程中各单元传质设备的数学模型,包括吸收-吸附塔、闪蒸罐、解吸塔。此外,还进行了灵敏度分析,探究了平衡级数、进料位置、气液比、解吸压力等因素对产品气中甲烷浓度以及回收率等工艺性能的影响。模拟结果表明,当产品气中甲烷浓度达到90.13%(mol)时,回收率为90.25%。并且单位原料气能耗为0.445 kW·h∙m-3(原料气),低于单塔能耗(0.510 kW·h∙m-3)。由此,改进的双塔工艺在满足甲烷纯度和回收率的同时,相较于单塔工艺进一步降低了能耗。

关键词: ZIF-8, 煤层气, 甲烷, 氮气, 吸附

CLC Number: