Separation and purification of syngas-derived hydrogen: A comparative evaluation of membrane- and cryogenic-assisted approaches.

Hydrogen (H2) separation and purification is challenging because of the high purity and recovery requirements in particular applications, as well as the critical properties of H2 and its associated components. Unlike pressure swing adsorption, cryogenic- and membrane-based technologies are currently employed for H2 separation. Membrane-assisted (case-I) and cryogenic-assisted (case-II) separation and purification of H2 were evaluated in this study in terms of the energy, exergy, and economic aspects of the processes. In case-I and case-II, H2 was first produced from synthesis gas via the water-gas shift reaction and was then separated from other components using membrane and cryogenic systems, respectively. Additionally, an organic Rankine cycle was integrated with the water-gas shift reactors to recover the waste heat. A well-known commercial process simulation software, Aspen Hysys® v11, was employed to simulate both processes. Energy analysis revealed that case-I has a lower energy consumption (0.50 kWh/kg) than case-II (2.01 kWh/kg). However, low H2 purity and recovery rates are the main limitations of case-I. In terms of exergy, the H2 separation section in case-I exhibited a higher efficiency (28.4%) than case-II (14.7%). Furthermore, the economic evaluation showed that case-I was more expensive ($17.7 M) than case-II ($10.2 M) because of the high cost of the compressors required. In conclusion, this study could assist industry practitioners and academic researchers in selecting optimal H2 separation and purification technologies for improving the overall H2 economy.

Exploitation of distillation for energy-efficient and cost-effective environmentally benign process of waste solvents recovery from semiconductor industry.

The waste solvent is unavoidably generated from the high solvent dependable processes. One of them is the semiconductor industry. The waste solvent is frequently incinerated to eliminate hazardous waste and this practice raises the issue of environmental and treatment costs. Thus, recovery of waste solvent is a substantial environmental mitigation option. This study explores the recovery of multicomponent waste solvents from the semiconductor industry. To achieve a greener and energy-efficient process, the recovery process is proposed through investigation of mixture thermodynamic behavior, process design, optimization, economics, and integration of renewable energy for environmental advantages. Herein, Distillation, a practical technology option for solvent recovery, with green solvent for extractive distillation and a new approach using renewable energy in waste solvent recovery are explored. As the result, waste solvent recovery by distillation with conventional energy exhibits bold advantages to cost and lower carbon process compared to waste disposal. The integration of renewable energy with about 37 % share of conventional energy as the backup indicates the highest annual cost-saving and reduces about 89.4 % of annual carbon emission compared to carbon emission from waste disposal.