Sustainable design and multi-objective optimization of eco-efficient extractive distillation with single and double entrainer(s) for separating the ternary azeotropic mixture tetrahydrofuran/ethanol/methanol

Comprehensive evaluation of an ionic liquid based deep purification process for NH3-containing industrial gas

Ammonia (NH3) emission has caused serious environment issues and aroused worldwide concern. The emerging ionic liquid (IL) provides a greener way to efficiently capture NH3. This paper provides rigorous process simulation, optimization and assessment for a novel NH3 deep purification process using IL. The process was designed and investigated by simulation and optimization using ionic liquid [C4im][NTF2] as absorbent. Three objective functions, total purification cost (TPC), total process CO2 emission (TPCOE) and thermal efficiency (ηeff) were employed to optimize the absorption process. Process simulation and optimization results indicate that at same purification standard and recovery rate, the novel process can achieve lower cost and CO2 emission compared to benchmark process. After process optimization, the optimal functions can achieve 0.02726 $/Nm3 (TPC), 311.27 kg CO2/hr (TPCOE), and 52.21% (ηeff) for enhanced process. Moreover, compared with conventional process, novel process could decrease over $ 3 million of purification cost and 10000 tons of CO2 emission during the life cycle. The results provide a novel strategy and guidance for deep purification of NH3 capture.

A novel reactive-extractive distillation process for separation of water/methanol/tetrahydrofuran mixtures

The design of separation systems for the purification of azeotropic mixtures is of great importance in the chemical industries from economic and environmental points of view. Two novel reactive-extractive distillation (RED) processes, new design (I) and new design (II), were proposed for separating the azeotropic mixture of water/methanol/tetrahydrofuran (THF). These processes were compared to a conventional extractive distillation (ED) process. New design (I) employs dimethyl sulfoxide as a solvent, while new design (II) utilizes ethylene glycol. Ethylene oxide was introduced to the first column in both designs, enabling the in-situ production of ethylene glycol, a valuable byproduct. This is a novel solution to separate water from the azeotropic mixture by reaction between ethylene oxide and water. Aspen Plus software was used to simulate and design the processes. Both suggested designs were compared economically with the base design which is an ED process. According to the results, the new design (I) is more cost-effective and environmentally friendly alternative to the base design and the new design (II). It has a lower total capital cost and produces less carbon dioxide. Additionally, it generates a valuable by-product, ethylene glycol, which can be sold for substantial revenue. As a result, the new design (I) is the preferred choice for replacing the conventional extractive distillation method.