Process Simulation and Optimization of Ammonia-Containing Gas Separation and Ammonia Recovery with Ionic Liquids

Abstract

Ionic liquids (ILs) have been experimentally proved to be effective for ammonia-containing gas separation and recovery. A systematic strategy including thermodynamic models, process simulation, multiobjective genetic algorithm, and assessment for novel IL-based separation of ammonia-containing tail gas and ammonia recovery process was proposed. The conventional IL ([C4Mim]­[NTf2]) and the functional IL ([C4im]­[NTf2]) were selected, and their NH3 removal performance was investigated. Physical properties of models of IL systems were established with temperature-dependent equations, and gas–liquid phase equilibria of the NH3-IL system were molded with the nonrandom two liquid model equation. Total purification cost (TPC), total process CO2 emission (TPCOE), and thermodynamic efficiency (ηeff) were selected as the objective functions to be optimized. Process simulation results indicated that under same operational parameters, using functional ILs results in lower NH3 concentration in purified gas and higher removal efficiency than that of conventional ILs. After optimization, a series of solutions satisfying the constraints was provided by the Pareto front. The lowest objective functions can achieve 0.0211 $/N m3 (TPC), 265.67 kg CO2/h (TPCOE), and 48.05% (ηeff). Moreover, using functional ILs could greatly decrease purification cost and energy consumption and avoid wastewater discharge, which is an inevitable environmental problem in the water scrubbing process.

Process Simulation and Optimization on Ionic Liquids

“…The first study reported the NH 3 absorption process simulation and optimization using two [NTf 2 ]-based ILs compared with traditional water scrubbing. 136 The authors use a multiobjetive optimization with three different objective functions (TAC, CO 2 emissions and NH 3 recovery). A genetic algorithm (NSGA-II) is used along several decision variables (theoretical column stages, feed stage, solvent flow, pressure and temperature of flash regeneration).…”

A Mini-Review on NH3 Separation Technologies: Recent Advances and Future Directions

“…Table summarizes the functional types and NH 3 absorption capacities of representative ILs reported in the literature. − The process simulations performed by Zhan et al and Liu et al demonstrated that the IL-based NH 3 separation process exhibits significantly reduced energy consumption, operation cost, and net CO 2 emission than an aqueous-based process. , However, it should be pointed out that most ILs are expensive because they are normally synthesized from expensive reactants or through complicated routes. In addition, most ILs are with high viscosity due to the strong electrostatic attraction between cations and anions .…”

TiO2 Nanoparticles Dual-Modified with Ionic Liquid and Acetic Acid for Use as Electrorheological Materials to Achieve Ultrahigh and Stable Electroresponsive Performances

“…ILs are of flexible designability in structures by adjusting the type of anion and cation, changing the length of the alkyl chain, or grafting functional groups on the cationic chain . The unique chemical structure makes ILs have low melting points, good thermal and chemical stability, high ionic conductivity, and adjustable polarity. , ILs have shown unique advantages in chemical synthesis, separation and extraction, and as electrolyte materials . In the synthesis of materials, ILs can be limited to the inorganic matrix to form the interpenetration of two continuous three-dimensional (3D) network structures, namely, an inorganic ionogel .…”