Determine compressor settling-out conditions for recycle gas loop design

S. Katkar, Foster Wheeler Asia Pacific, Singapore The recycle gas compressor (RGC) is one of the most important pieces of equipment in hydrotreaters, hydrocrackers and catalytic reformer units. A typical reactor recycle gas loop used in a hydrotreater unit is shown in Fig. 1. This loop consists of a reactor, a fired heater, a feed/effluent exchanger, a product cooler, a separator drum and interconnecting piping. Fig. 1. Process flow of a typical recycle reactor gas loop. Design conditions of RGC loop equipment are not only based on maximum operating conditions, but also on settle-out conditions, which can be defined as the equilibrium pressure and temperature when th