Combustion Engineering, Inc.

Henry J Blaskowski

Arun K Mehta

David Palchik

A method for restoring slagging conditions in a substoichiometric slagging combustor first requires the establishment of a threshold condition below which an unacceptable risk of slag outlet pluggage exists. Upon observation of current slagging conditions below the threshold conditions, substantially pure oxygen is injected into the combustion reaction zone to increase both zone temperature and reaction rate, leading to improved slagging conditions within the slagging combustor.

Method for preventing plugging of a slag outlet in a substoichiometric

A coal and char burner (10) is formed of three concentric cylinders (14,16,18). The central passage (32) conveys char particles into the interior (20) of a coal gasifier. Fresh coal and secondary air enter the gasifier through concentric passageways (24,27) surrounding the central passageway (32). The coal and air form a high temperature reaction envelope (30) which surrounds the char stream (22) and rapidly heats the char particles.

Coal and char burner

A process for producing pressurized pipeline gas wherein coal is gasified in oxygen at a relatively low pressure, typically less than 5 atmospheres, to produce a raw gas containing carbon monoxide, hydrogen, carbon dioxide, gaseous sulfur compounds and particulates. A major portion of the raw gas is cooled, cleaned and methanated to produce a pipeline quality product gas consisting essentially of methane. The remaining portion of the raw gas is cleaned, compressed and combusted to produce a high temperature, high pressure flue gas which is used to power a gas turbine and generate steam to power a steam turbine. The gas turbine and steam turbine each drive compressors for compressing the low pressure product gas to pipeline pressure.

Production of pipeline gas from coal

A fluidized bed call (10) having a static ignition bed (18) of inert heat storage particles (50) disposed immediately beneath and adjacent to a fluidizing region (44) wherein fuel particles are combusted, characterized in that the heat storage particles (50) are generally spherical in shape, each particle having a plurality of protuberances (52) extending outwardly from the surface of the particle a preselected length thereby maintaining a minimum spacing, equal to the preselected length of the protuberances, between neighboring spherical particles within the static ignition bed thereby ensuring that sufficient void space (54) exists within the static ignition bed for the fluidizing air to flow upward through the static ignition bed into the fluidizing region without an excessive pressure drop and for the fuel particles to laterally penetrate the static ignition bed.

Fluidized boiler

A method for rapidly changing the amount of pulverized coal supplied to a coal-fired furnace (10) equipped with a coal pulverizer (20) from a first steady-state level to a second steady-state level in response to a change in operating load demand. The amount of pulverized coal supplied to the furnace is instantaneously increased by providing pulverized coal to the furnace from a source (42) independent of the pulverizer or instantaneously decreased by diverting away from the furnace a portion of the pulverized coal being supplied by the pulverizer.

Method of improving load response on coal-fired boilers

Apparatus for obtaining complete mixing of char with coal prior to the introduction of the mixture into the combustor (30) of a coal gasifier (10). The coal is carried in one air stream (22), and the char in another air stream (54), to a riffle plate arrangement (26), where the streams of solid are intimately mixed or blended.

Apparatus for mixing char-ash into coal stream

A segmented ring header is disposed between and welded to two pressure containment vessels. The segmented ring header comprises a first hemi-toroidal shell having a plurality of openings around its inner circumference shaped to mate with heat transfer tubes lining the first pressure containment vessel, a second hemi-toroidal shell having a plurality of openings around its inner circumference shaped to mate with heat transfer tubes lining the second pressure containment vessel, and a flat ring-shaped plate disposed between the first and second hemi-toroidal shells and welded therebetween. Both the first and second hemi-toroidal shells also have a plurality of openings along their outer circumference for directing the cooling fluid to a collection drum located outside of the pressure containment vessels. The hemi-toroidal shells are circumferentially welded to their respective pressure vessels along a locus located radially between the plurality of openings along the inner circumference of the shell and the plurality of openings along the outer circumference of the shell.

Segmented ring header

A heat exchanger having a shell lined with a plurality of heat transfer tubes, heat exchange surface disposed within the shell and submerged in a first heat transfer fluid, and a tube manifold penetrating through the shell and directing a second heat transfer fluid to and from the heat exchange surface. The tube manifold has an elongated L-shaped outer enclosure which has one leg disposed within the shell and the other leg penetrating through the shell, and an elongated L-shaped inner tube which passes through the outer enclosure. A first fluid flow path through the tube manifold is established through the inner tube and a second fluid flow path through the tube manifold is established between the inner tube and the outer enclosure.

Superheater inlet/outlet header

A steam generating heat exchanger of modular design for cooling a high pressure, hot combustible gas laden with molten ash particles comprising a first convective cooler having a vertically orientated U-shaped gas pass housing a superheater and an evaporator, a radiant cooler disposed upstream of the first convective cooler and a second convective cooler housing an economizer disposed downstream of the first convective cooler. In-line tube bundles form the superheater, evaporator, and the economizer thereby minimizing ash deposition upon the heat transfer surface. The gas velocity within the radiant cooler is maintained low enough to permit molten ash particles entrained in the gas to coalesce and precipitate out of the gas stream, while the gas velocity within the convective coolers is maintained high enough to discourage ash deposition upon the heat transfer surface.

Steam generating heat exchanger

An individual cell of a fluidized bed includes a static bed disposed immediately below the fluidization region with a coal feed system, which incorporates means for igniting the coal, embedded within the static bed. Coal is fed to the static bed through a coal pipe which extends vertically upward through the bed support plate into said bed and which terminates therein in a coal distributor having a series of openings around its circumference. The coal is swirled as it flows upward through the coal pipe with resultant centrifugal force imparted to the coal ensuring that the coal will be propelled out of the openings in the distributor head and evenly distributed over the cell area.

Coal feed system for a fluidized bed boiler

A combined cycle electric power generating plant having a steam generator and a gas turbine in which low Btu gas from a coal gasifier is the fuel. The gas turbine drives the compressors for both the air and low Btu gas used to generate the hot combustion gases therein. In addition, the oxygen-containing exhaust gases from the gas turbine are used to support combustion of the fuel in the steam generator.

Combined cycle power plant using low Btu gas

A reciprocable soot blower that is adapted to extend laterally through an outer wall to remove deposits of slag that collect on the walls of a pressurized furnace, gasifier or other reactor. The soot blower is telescopically mounted in a conduit attached to an outside wall of the furnace to permit its complete withdrawal from the furnace when not in use. A steam seal is adapted to be activated in the conduit when the soot blower is extended to increase pressure in the conduit to thus prevent entry of foreign material from said furnace into the space between the conduit and the soot blower.

Soot blower for pressurized furnace

An individual cell of a fluidized bed includes a static bed disposed immediately below the fluidization region. The static bed contains heavy ores or other suitable dense material that can be heated to a temperature above the ignition temperature of the fuel used in the fluid bed. Should the fluidized-bed temperature fall below the ignition temperature of the fuel, the lower thermal conductivity of the static bed permits it to maintain the ignition temperature and to ignite the fuel until the fluidized bed has been rekindled.

Fluidized bed boiler

A soot blower for use in a tubular heat exchanger, gasifier or reactor that is installed in parallel alignment with a bundle of elongate tubes therein. The soot blower is adapted to eject a jet of steam radially over the outer surface of said tubes to remove deposits therefrom. The steam jet may be moved axially to progressively clean the length of the tubes and the operation of the soot blower may be activated or terminated without interfering with fluid flow over or through said tubes.

Soot blower for tube bundle in pressurized enclosure

A method of operating an entrained flow coal gasifier which comprises the steps of firing coal at two levels in a combustion zone with near stoichiometric air, removing molten ash from the combustion zone, conveying combustion products upwardly from the combustion zone through a reduction zone, injecting additional coal into the combustion products in the reduction zone and gasifying at least a portion of the coal to form low BTU gas, conveying the gas to a point of use, including also reducing gasifier output by modifying the ratio of air to coal supplied to the upper level of the combustion zone so that the ratio becomes increasingly substoichiometric thereby extending the gasification of coal from the reduction zone into the upper level of the combustion zone, and maintaining the lower level of coal in the combustion zone at near stoichiometric conditions so as to provide sufficient heat to maintain effective slagging conditions.

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West Simsbury, CT, United States of America

Henry J Blaskowski