Energy saving in NMP (N-methyl-2-pyrrolidone) recovery process by numerical modeling

Abstract

N-methyl-2-pyrrolidone (NMP) is a solvent widely used in many industries, such as electronics, petroleum, paint, textile, rubber, chemical, and polymer industries, etc. Therefore, NMP would become waste, and the production of NMP is important. Recycling and reusing NMP waste is one of the ways to reduce production costs. Distillation is one of the technologies used for extracting mixtures waste NMP/water/PR (praseodymium) to be pure NMP However, it requires a lot of energy, and heat integration is proposed to reduce the energy required. In addition to reducing operational costs, hot steam waste from neighboring companies is proposed as a fuel for reboilers and preheating. This study simulated distillation using Aspen Plus v10 and analyzed the total energy consumption, the total annual cost, and gas emissions. The heat-integrated system in the single-column distillation process shows the best performance in the NMP/water/PR separation processes. This scenario produced 658.025 kg/h with 99.99% NMP. Compared with conventional design, this scenario could save 61.83% of energy, 58% of TAC, and reduce 61.84% of gas emissions and emissions costs.