Improvement in Grs Compressor System to Increase Reliability of Combined Cycle Power Plant PT. PJB UP Muara Tawar

Abstract

Fuel gas is the main fuel used in PT PJB UP Muara Tawar combined cycle power plant. Reliability of combinend cycle power plant can be affected with fluctuative supply of fuel gas. Fuel gas supplied by PGN with pressure range 24-26 barG. Because of fluctuative pressure from supplier, pressure of gas must be adjusted by using Gas Receiving Station (GRS) system. There are HMI local panel in GRS as interface. HMI local panel consist of bypass system and fuel gas compressor system. Bypass system used to decrease gas pressure when gas pressure above the upper limit while compressor used to increase gas pressure when gas pressure under lower limit. GRS have an important role in operational Block 5 PT PJB UP Muara Tawar. In 9 December 2011-26 Januari 2015 period, Block 5 can not be operated because of mechanical seal failure in fuel gas compressor in GRS. Ordering new seal has take a long time. GRS can not be operated when compressor gas fail due to fluctuatif pressure of supplied gas. Moreover, GRS has far distance from main control room (MCR). It will be difficult to monitor GRS parameter from control room. By this problem, research and improvement in GRS should be done so that performance of GRS can be improved. Improvement in low limit fuel gas pressure was performed. By this changing, inlet pressure GT operation has wider range. In addition, making 1K changeover can increase GRS performance. The addition of overview, parameters, alarm indicators on Alspa HMI can improve the reliability of the operation of Gas Turbine because the operator can respond faster when there is a change of parameters in GRS.