CCS and Power Systems

Advanced Energy Systems - Advanced Combustion Systems

Optimization of Pressurized Oxy-Combustion with Flameless Reactor

Performer: Unity Power Alliance, LLC

Project No: FE0009478

Project Description

Unity Power Alliance, in collaboration with their partners, will examine a novel pressurized oxy-combustion technology with potential for increasing process efficiency and reducing emissions and costs associated with CO2 capture and compression. This project will advance the state of the art in oxy-combustion technology by laying the groundwork for development of a pilot-scale oxy-combustion facility operating at very high pressure (up to 70 bar) with a heat recovery steam generator (HRSG) inlet temperature of 700 °C (current technology is at 605 °C) using a flameless combustion reactor. The system is expected to achieve an approximately 10 percent efficiency improvement over oxy-combustion at atmospheric pressure, reduce costs associated with CO2 compression, and avoid the need for costly and energy-intensive flue gas treatment.

The use of high pressure is expected to reduce the cost of electricity (COE) by improving generation efficiency through higher heat transfer rates, recycling of high temperature condensate, and by reducing capital and operating expenses associated with pressurizing the emitted CO2. In addition to the efficiency benefits, the capture of CO2 at higher pressure would enable nearly 100 percent CO2 capture and would cause the power cycle to generate more water than it consumes (the system would be "net water positive"). Condensate could be recycled for use in preparation of the coal-slurry feedstock, significantly reducing the water demands of the system.

In contrast to a conventional coal combustion furnace, flameless combustion approximates the conditions of an isothermal chemical reactor in which temperatures remain uniform and constant throughout the reaction process. This highly-efficient, carefully controlled reaction promotes complete combustion of coal at high temperatures with negligible generation of airborne particulates or hazardous pollutants. The majority of the pollutants that are normally released in flue gas are instead permanently entrained in a vitrified or glass-like slag. As a result, the use of a flameless reactor mitigates the need for costly and energy intensive flue gas treatment.

In Phase I, the project will encompass two independent research efforts: (1) computer modeling and optimization of pressurized oxy-combustion with a flameless reactor, and (2) design, construction, and testing of a 100 kilowatt (kW) bench-scale flameless reactor.

Project Details