Economic and Environmental Comparison of Integrated Processes to Produce Chloromethanes from Brine Waste and CO2

Thiswork provides an economic and environmental comparison oftwo processes (direct chlorination of methane and hydrochlorinationof methanol) to produce chloromethanes from waste brine and CO2. Both processes are modeled using an equation-based approach.This allows for determining the optimal operating conditions of allof the units involved in the process. In particular, those relatedto the reactors. The optimization determines that hydrochlorinationof methanol is a more profitable process (a minimum selling priceof $1.8/kgmethyl chloride) than direct chlorination(& SIM;$5/kgmethyl chloride) since the conversionachieved in hydrochlorination is approximately 5 times greater, althoughthe desired product among all of the chloromethanes in direct chlorinationis also methyl chloride. Furthermore, direct hydrochlorination alsohas higher emissions, 16.2 kgCO2 /kgmethyl chloride vs 4.6 kgCO2 /kgmethyl chloride, for hydrochlorination of methanol. These emissions are mainly dueto the electricity required in the electrolyzer and could be reducedto -0.5 kgCO2 /kgmethyl chloride (CO2 is absorbed) if the electricity source is fullyrenewable. The renewable energy alternativesand processing routesevaluated in this work for the production of chloromethanes.