(24f) Simulation and Energy Assessment of Ammonia-Containing Gas Separation and Recovery Process with Ionic Liquids

Simulation and energy assessment of
ammonia-containing gas separation and recovery process with ionic liquids

Guoxiong Zhan^1,2,3,
Fei Chang^1,2, Shaojuan Zeng¹, Zengxi Li², Xiangping
Zhang^1,2*

¹Institute of Process Engineering, Chinese Academy of
Sciences, 100190, Beijing, China

²School of Chemical Engineering, University of Chinese
Academy of Sciences, Beijing, 100049, China

³Sino-Danish College, University of Chinese Academy of
Sciences, Beijing, 100049, China

*Corresponding author email:
xpzhang@ipe.ac.cn

Abstract: Huge
amounts of toxic gases (e.g. NH₃) and greenhouse gases (e.g. CO₂)
emission have caused serious environment problems. Besides, more strict laws
and standards have been proposed to reduce emissions and punish the action of
excess emissions in recent years. Therefore, NH₃ and CO₂
separation from industrial gas is considered as a significant and essential
technology to reduce atmospheric pollution. The traditional water method is used
to separate NH₃ and CO₂ from industrial gas, but it led
to a lot of ammonia-nitrogen wastewater, high energy consumption, low NH₃/CO₂
separation efficiency and NH₃ recovery ratio. Therefore, there is
still a great challenge to get an effective way to separate and recover NH₃
and CO₂ from tail gas. Ionic liquids (ILs) has already been applied
in industrial tail separation due to extremely low volatility and good affinity
with gas molecule ^[1]. In this work, novel ILs with good selectivity
towards NH₃/CO₂ and high NH₃ absorption
capacity were designed and synthesized. The thermodynamic data between NH₃/CO₂
and ILs were measured and regressed by the NRTL equation ^[2]. Based
on those results, the separation process of ammonia/carbon dioxide-containing
gas with ionic liquid has been simulated and optimized. The result indicates
that the designed IL can reduce NH₃ concentration under 1000 ppm in
tail gas, and the removal efficiency and recovery purity are 70% and over 97%,
respectively. Then, based on the former results, the assessment of energy,
economy and green degree for separation system has been calculated to figure
out the integrated performance of the system under varied situations. The
results can provide guidelines for developing new absorption process to meet
lower NH₃ concentration emission, higher NH₃ purity and
recovery ratio along with lower energy consumption.

Keywords: Ionic
liquids; gas separation; NH₃; CO₂; process simulation;
energy assessment

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