Design of an ideal gas regulating and metering station for gas supply to A 50 MW power plant

Abstract

In gas transmission and distribution system, the gas pressure and flow rate are controlled by using CGS, TBS, DRS and RMS. It is important to supply uninterrupted gas at a desired pressure and flow rate to the customer premises. The Regulating and Metering Station (RMS) is generally used for controlling the gas pressure and measuring the gas volume for fiscal purpose. It is apparent that proper design of RMS is very important for a customer for supplying desired amount of gas at a required pressure as well as measuring the supplied gas accurately which is very much crucial for gas supplier in fiscal context. A large number of RMS’s are used for gas supply to different customers in the Titas franchise area. The major objective of this project is to design an ideal gas Regulating and Metering Station for uninterrupted gas supply to a 50 MW power plant. In this project work, fluid characteristics, process data, gas safety rules, International codes and standards (ASTM, ASME ANSI, API) have been followed for the proposed RMS design. Design considerations, selection criteria and installation of RMS equipments are incorporated. Safety and Environmental issues have been considered in designing the gas facilities for the power plant. The negative effects on environment are negligible. The gas load of the power plant is calculated around 12 MMSCFD at minimum outlet pressure of 50 psig. Design has been checked allowing variation of some related variables such as inlet pressure, specific density, specific heat, compressibility factor and heating value. Variation of these parameters needs no change in the design. Instrumentation and piping diagrams of the proposed RMS are also shown in the report. Some recommendations have been made for improvement of the RMS design. Finally, cost estimation is performed for the project. The cost estimation of the project have been calculated on the basis of preconstruction expenditure, construction cost and material cost. The total cost of the project is estimated as Tk. 494.463 Lakh.