APPARATUS FOR THE COMBUSTION OF COMMINUTED SOLID CARBONACEOUS FUEL AND SEPARATION OF THE NON-COMBUSTIBLES PRESENT IN THE FUEL FROM THE GASEOUS PRODUCTS OF COMBUSTION

摘要

pDescribed is a slagging coal combustion system suitable for retrofitting boilers, furnaces and industrial-process heat generators originally designed to burn oil or gas. It comprises a fluid-cooled primary combustion chamber into which oxidizer and fuel are injected to provide high-velocity rotational flow combustion zones such that the fuel is burned substoichiometrically, while in flight, with up to 90% of the ash being removed as molten ash. A swirling mixture of combustion products passes from the primary chamber to an expansion chamber where more slag is removed and the gaseous products are passed upwardly and thence to an end-use equipment, such as a boiler or industrial furnace. As the gaseous combustion products arrive at the interface with the end-use equipment additional air is mixed with the hot, relatively clean, gaseous products from the combustion system. Final combustion takes place, therefore, in the end-use furnace, boiler or kiln. Subsystems for injecting fuel and oxidizer into the primary combustion chamber are independently controllable so that the substoichiometric combustion conditions may be regulated to simultaneously minimize nitrogen oxides (NOx), maximize separation of noncombustibles as molten slag, avoid carryover of soot and assure durability and combustion stability. The apparatus is constructed and arranged for injection of sulfur sorbents into a fuel-rich portion of the combustion zone thereby enhancing capture of sulfur compounds in the slag. A coal-fired precombustor subsystem feeds partially vitiated air to the primary combustion chamber, as its sole supply of oxidizer, at any selected temperature within the range from about 1200.degree.F to about 2000.degree.F. The stoichiometry of this precombustor and the velocity and mass-flow rates of its output stream are independently controllable./p[CA1262839A]