Multi-objective Optimization on Driving Options for Rotating Equipment in Process Industries to Make Trade-offs between Economy and Environmental Impacts

Abstract

In process industries, steam turbines and electric motors are usually selected to be the choice of drivers for pumps and compressors. The economy of the drivers is usually one of the critical factors when the decisions of drives for pumps and compressors are made. In this work, we proposed a multi-objective optimization model to simultaneously minimize the total annual costs and environmental impacts. In the proposed model, the capital and operational costs for the drivers were included in the economic objective and the environmental impacts was measured by the indexes of Eco-indicator 99. The driving system in a diesel hydrotreating unit was taken as a case study to exemplify the proposed method. Under the circumstances of fixed and variable prices of electricity and steam, the influences on Pareto fronts and trade-off points were obtained and discussed. Results show that the steam turbines are favorable in the driving system when the environmental impacts are mainly considered. The drives option schemes are sensitive to the change of electricity and steam prices, and the environmental impacts of the drives option should not be ignored.