Optimization of energy efficiency in natural gas liquefaction process using plantwide control method

Abstract

The use of hydrocarbon energy is still very dominant, where the most efficient hydrocarbon energy is natural gas. In the process of distribution, natural gas must be cooled first to become liquid or commonly referred to as LNG. The natural gas liquefaction process consists of three parts, namely the propane cooling cycle by sea water, the MCR cooling cycle by propane, and the natural gas liquefaction cycle by MCR. The design of PWC on LNG aims to increase the efficiency of energy consumed so that the maximum profit can be obtained and to increase the plant stability when given disturbances. The results of the PWC design on a 5% increase in feed is able to reduce the energy use by 85,867,151 kJ / hour and increase the profit by 2,010,321,775 rupiah / day. While the 5% decrease in feed can reduce energy use by 96,297,243 kJ / hour and increase the profit by 2,254,511,068 rupiah / day. The application of PWC is able to produce a stable system response when a disturbance test is done, proven by the decrease of settling time and overshoot, also eliminating the steady state errors compared to PID control before using the PWC design.