Under these projects, researchers from the National Energy Technology Laboratory’s (NETL) Office of Research and Development will investigate two advanced concepts for coal combustion integrated with carbon dioxide (CO₂) removal: oxy-combustion and chemical looping combustion (CLC).

Pulverized coal oxy-combustion power plants are designed to utilize high-purity oxygen (O₂) mixed with recycled flue gas (primarily CO₂) to combust coal and produce a highly concentrated CO₂ stream (greater than 60 percent by volume). The CO₂ is further purified by condensing the water (H₂O) vapor and potentially additional treatment to reduce other gas constituents, depending on the end-use and pipeline specification. NETL will commission a lab-scale burner suitable to study basic features of oxy-combustion. Test data, coupled with computer modeling results, will be utilized to evaluate flame characteristics, burner and coal-feed design, and the interaction of oxy-combustion products with boiler materials to ensure the development of low-cost and efficient oxy-combustion power plant systems.

An advanced coal oxy-combustion technology, CLC, involves the use of a metal oxide or other compound as an “oxygen carrier” to transfer O₂ from the combustion air to the fuel. Since direct contact between fuel and combustion air is avoided, the products from combustion (CO₂ and H₂O) will be kept separate from the rest of the flue gases. CLC splits combustion into separate oxidation and reduction reactions. NETL will combine laboratory studies of “oxygen carriers” with computer models to refine and optimize the CLC process.

Process Flow Diagram for Oxy-Combustion with Flue Gas Recycle