Battelle Development Corporation

Herman Nack

Ke-Tien Liu

Robert E Maringer

Richard Razgaitis

William J Huffman

Billy R Allen

A recirculating fiber filter (1) and method is provided for removing particulates from moving fluid streams. High aspect ratio fibers (2) are used which readily nest with each other to form the high voidage fiber filter bed. In the method, fibers are continuously removed from the bottom of the bed regenerated to remove particulates and recycled back to the top of the bed and distributed thereon. Dirty fluid is passed from the top to the bottom of the filter. Dendrites of the particulate impurity appear to buildup in a thin section (A) at the top of the filter and provide the primary mechanism for further particulate entrapment. Recirculation of fibers offers a continuously fresh volume of fibers at the top for capture of particulates.

Nested, recirculating-fiber filter

Nitrogen oxide pollutants are substantially reduced and sulfur dioxide minimized in multisolid fluidized beds by staged combustion of the fuel. The lower combustion region is operated at substoichiometric conditions such that NO.sub.x is reduced by carbon and carbon monoxide to nitrogen gas. The upper combustion region is operated at excess oxygen conditions to complete the combustion of char and carbon monoxide. Elevated temperature excursions in the upper region which deter sulfur capture are prevented by recycling cool entrained bed particles therethrough.

NO.sub.X reduction in multisolid fluidized bed combustors

Continuous chemical and biological reactions may be carried out in a liquid fluidized reactor (1). Improved mixing and mass transport between gas/liquid/solid phases is provided by fluidizing large particles (2) with a liquid in a dense bed in the bottom of the reactor (1) while recirculating small entrained particles (3) and the liquid through the reactor (1), particle separator (9), external regenerator (10) and conduits (7) and (8) back through the dense bed of large particles (2).

Liquid multisolid fluidized bed processing

A method of operating a fluidized bed system in a single vessel, typically as a combustor system for power or steam generation burning high-sulfur coal or as a gasifier for high-sulfur coal, which comprises forming an entrained fluidized bed in a first space region containing a first solid bed particle component, such as sand or hematite ore containing over 90% Fe.sub.2 O.sub.3, forming in a limited space region partially within the first region a dense fluidized bed containing a second solid bed particle component, such as larger particles of the hematite, both first and second component particles essentially comprising a material having long-term physical and chemical stability in the fluidized bed system so as to be substantially nonagglomerating and not subject to substantial attrition therein, effecting division of the dense fluidized bed into upper and lower zones, providing a recirculation path such as through a cyclone separator and particle reservoir for the first particle component from the first space region through the upper zone of the dense fluidized bed in the more limited space region, operating the fluidized bed system at a velocity such that the second component particles are effectively retained in the dense fluidized bed in the more limited space region, whereas the first component particles recirculate and interpenetrate through the upper zone thereof commingling with the second component particles, and maintaining different temperatures in the upper and lower zones of the dense fluidized bed. Typically, the temperature of the upper zone of the dense fluidized bed is conducive to capture of sulfur gases by a sorbent while a high temperature in the lower zone of the dense fluidized bed is maintained to be conducive to combustion of fuel and calcination of sorbent (for combustors) or gasification of fuel (for gasifiers).

Two-zone fluid bed combustion or gasification process

A method of operating a fluidized bed system, typically as a combustor system for power or steam generation by burning high-sulfur coal, which comprises forming an entrained fluidized bed in a first space region containg a first solid bed particle component, such as a hematite ore containing over 90% Fe.sub.2 O.sub.3, or limestone, forming in a more limited space region within the first region a dense fluidized bed containing a second solid bed particle component, such as larger particles of the hematite, essentially comprising a material having long-term physical and chemical stability in the fluidized bed system so as to be substantially non-agglomerating and not subject to substantial attrition therein, providing a recirculation path such as through a cyclone separator and particle reservoir for the first particle component from the first space region through the dense fluidized bed in the more limited space region, and operating the fluidized bed system at a velocity such that the second component particles are effectively retained in the dense fluidized bed in the more limited space region, whereas the first component particles recirculate and interpenetrate therethrough, commingling with the second component particles.

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Columbus, OH, United States of America

Herman Nack