Thermo-Hydraulic Design and Analysis of Heat Exchanger for Reciprocating Gas Compressor System

Abstract

Dresser-Rand India Private Limited manufactures Reciprocating gas compressor systems. Heat exchangers are used in the system for cooling of gas, compressor jacketing water and lubricating oil. In reciprocating compressors, isothermal cooling is preferred for minimum work input and hence higher thermal efficiency. Also, gas cooling is required to achieve specific temperature for different stages in gas compressor system. To achieve this, Shell and tube and Air cooled heat exchangers are used as an inter-cooler or after-cooler for cooling of gas in gas compressor system. Depending on the service and operating conditions, both single acting and double acting compressors require water jacketing. The primary reason for water jacketing is to keep the cylinder wall and piston rings far from getting too hot. Lubricating oil is used for lubrication as well as for cooling of bearings and connecting rods. For the cooling of jacketing water and lubricating oil, Shell and tube and Air cooled heat exchangers are used in the reciprocating gas compressor system. In the present study, fundamentals of heat exchangers are discussed. Literature review pertaining to Shell and tube and Air cooled heat exchangers are presented. Analytical designs of Shell and tube heat exchanger, used for gas cooling, as well as Air cooled heat exchangers, used for cooling of jacketing water and lubricating oil, are presented. The design is verified with HTRI software for few of the heat exchangers as different case studies, data for which was provided by the company. CFD analysis of Shell and tube heat exchanger is presented. Effects of various modifications like unequal baffle cuts and number of baffles on pressure drop were numerically simulated.