Demand oriented planning of methanol-dimethyl ether co-production system for CO2 reduction

Abstract

This work addresses an optimal design method for a methanol-dimethyl ether co-production system with the fluctuations in supply and demand, aiming to utilize the CO2 from point sources as much as possible in actual industries. In the proposed method, a design and optimization model of the chemical co-production system is established with the aim of the lowest total annualized cost, and rigorous simulations are conducted to determine the cost flows of the operation units in the system. The optimal design, operation, and scheduling schemes of the co-production system can thus be determined by solving the proposed model. The application of the method is finally verified via an actual case study where a 330 MW off-design thermal power plant is taken as the carbon source and the product demand and price are determined according to the market. Results showed that the renewable chemical co-production system features the advantages of coping with supply and demand fluctuations by flexibly adjusting the production, storage and sale capacities of the products, thus achieving the maximum economic benefits and carbon reduction efficiency of 94.7%. The electricity consumption for electrolysis is the main contributor to the total annual cost of the system, accounting for more than 70%. Besides, expanding the capacity adjustment range of the dimethyl ether synthesis process can not only improve the ability of the system to deal with economic fluctuations but also help to reduce the capacity of storage tanks. It is foreseeable that the proposed system can be competitive in the near future with the formulation of new policies and the development of advanced technologies.