Compact Coal Combustor with Integral Dry Ash Removal. Annual Report, October 1, 1983-September 30, 1984

摘要

A promising approach for conversion to coal of existing oil and gas-fired boilers is to retrofit with a combustor that removes most of the ash before the boiler. The present project has resulted in the design and preliminary proof-of-concept testing of such a combustor. The outstanding characteristics of this non-slagging, dry ash removal combustor are listed: (1) Combustion and dry ash removal in one compact unit confines deleterious ash effects (corrosion-erosion) to this stage. (2) Dry ash operation throughout allows use of lower temperature and less costly materials or, with the best available materials, longer life and high reliability. Corrosion by slag, slag tap plugging and the difficulties of handling molten ash are avoided. Low temperature operation is more compatible with pre-cleaned coal water mixture as the fuel. (3) Simple inertial ash separation can be independently controlled to give reliable and effective ash removal even under turndown conditions. (4) The dry ash operation and the independent control of ash separation assures stable and good performance under turndown while the need to maintain a thin mobile slag layer, in the case of the slagging cyclones, would make it sensitive to turndown. (5) Dry ash combustion of moderately loaded CWM's (50% coal) without support fuel and external air preheat has been demonstrated on the test unit. (6) Excellent carbon conversions (greater than 90%) have been attained over a wide range of thermal inputs, combustion intensities and air-fuel ratios. (7) The potential for dry ash removal has been shown with removal efficiencies greater than 60% overall. The next logical step toward commercialization of this technology, requires generation of a data base by testing a larger size, more representative unit. 11 figs., 8 tabs. (ERA citation 11:025314)