Conceptual Design of an Ultra-Dense Phase Injector and Feed System

Pratt & Whitney Rocketdyne (PWR) has developed an innovative gasifier concept that uses rocket engine technology to significantly improve gasifier performance, life, and cost compared to current state-of-the-art systems. One key feature of the PWR concept is the use of an ultra-dense phase feed system to provide dry coal to the multi-element injector. This report describes the design of an ultra-dense phase multi-element injector and feed system for use on PWR gasifiers operating at pressures to 1,000 psia. For the design of this injector and feed system, the pulverized coal's Bingham fluid yield stress is approximately 11 Pascals (Pa) with a coefficient of rigidity of 10 centipoise (cp). These values are typical of earlier experimental testing conducted with dried pulverized coal below 18 wt% moisture -- see, e.g., Sprouse and Schuman (1983, 1986). Each individual injector element is designed for a coal flow rate between 3 and 4 tons/hr (0.76 to 1.0 kg/sec) at full flow conditions. Hence, a small 400 to 500 tons/day (4.2 to 5.25 kg/sec) gasifier will require a 6-element injector, a 1,500 tons/day (15.7 kg/sec) gasifier will require an 18-element injector and a 3,000 tons/day (31.5 kg/sec) gasifier will require a 36-element injector. These injectors and feed systems are capable of 'turn-down' below 50% of full-flow operation