Hot and Dry Char Letdown System for the Synthane Pilot Plant. Phase II Report

摘要

The SYNTHANE process demonstration plant is designed to process three tons per hour of any type coal and convert it to high Btu gas. In the gasification process a carbonaceous combustible char having a heating value of 9000 to 10,000 Btu/lb is produced as a by-product: Approximately 0.3 pound of char per pound of coal feed. To render the SYNTHANE process energy effective it is important that the energy available in this char be recovered since it represents a significant proportion of the available energy in the coal. The char exits the gasifier at temperatures up to 1800 exp 0 F and pressures to 1000 psig. At these conditions the char contains a substantial amount of energy as fuel and as sensible heat. In the demonstration plant no attempt is presently made to recover either the heating value or the sensible heat of the char. In a commercial plant means for recovering this energy must be provided. Initial planning indicated the most expedient method of heat recovery is dry depressurization of the char stream to essentially atmospheric pressure followind by combustion in a conventional boiler. To maximize the heat recovery and to assist combustion it is desirable to maintain the char temperature entering the boiler as high as possible. The Lummus Company was awarded a contract to provide the design, simulation testing, and fabrication of a commercially scaleable system to discharge hot dry char from the Bruceton demonstration plant and be compatible with the downstream heat recovery boiler. Phase I consisted of the conceptual design and analysis of a cascade of restrictive nozzles arranged in series to stepwise reduce the pressure of the char laden gas stream leaving the gasifier to the boiler firebox conditions. This report covers Phase II which included the design, construction, and cold flow testing of a pilot plant to verify the theoretical predictions made in the Phase I effort. (ERA citation 03:046238)