Process design for energy efficient, economically feasible, environmentally safe methyl chloride production process plant: Chlorination of methane route

Abstract

Methyl chloride is the starting raw material for chloromethanes and the demand for chloromethane is increasing steadily in the world market. Continuous improvement in product quality, reducing the product cost, improving the operation efficiency, minimizing the environmental emissions, and enhancing the process plant safety are some of the challenges or constraints facing by the chloromethane industry. In this research work, an attempt has been made to address these challenges using process systems engineering. As a first step, a process simulation model is designed conceptually using the Aspen HYSYS V11 for the production of 99.9 % pure methyl chloride from the methane chlorination route. Energy analysis is performed for the effective utilization of the utilities by adding one new heat exchanger. This modification reduced the utility cost by 31.17 % and recovered the 13028 kW of energy from the process with a payback period of 0.8759 years. Energy savings reduced the product cost by 3.26 %. Heat integration reduced greenhouse gas emissions by 16.5 %. Process plant safety is improved by using depressurization studies. Safety calculations are performed for the storage tank protection and the tank is used for the storage of methyl chloride product. Sizing calculations are performed for safety valves to vent off excess vapor through pressure safety valves to protect the equipment against overpressure scenarios. Process design engineers and process safety engineers can use the methodology developed in this study to design energy-efficient, economically feasible, and environmentally safe chemical process plants.