JPH0433992A - Coal-gasifying device - Google Patents

Abstract

PURPOSE:To provide the subject device capable of being employed for many kinds of coal without requiring a desulfurizing device, a dust collector, etc., at a low cost by composing a coal gasification furnace main body, hoppers for dry-desulfurizing raw coal and lime stone fed therein, an ammonia water- spraying device for denitration, etc. CONSTITUTION:Raw coal and lime stone are fed on a grid 2 disposed in the main body 1 of a coal gasification furnace from a raw coal hopper 3 and a lime stone 4 through control valves 18, 17, and air for combustion is fed from an air duct 5. The furnace is heated with a auxiliary combustion burner 14 and the raw coal is burnt to start the gasification combustion. Ammonia water is simultaneously fed from an ammonia water tank 11, raised through a heat exchanger 10 in a clinker hopper 8 and sprayed from an ammonia nozzle 13 to denitrate the produced gas. The produced gas is subjected to a dust-removing treatment with a classifier 7 disposed at the upper portion of the gasification furnace main body 1, guided in the burner 16 of a boiler flame furnace 15 from a produced gas-discharging dust 6 and burnt in the furnace 16.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a coal gasifier.

[Conventional technology]

Conventionally, pulverized coal direct combustion and fluidized bed combustion have been used to burn coal and generate steam using the heat of combustion. However, the ash content in the coal causes wear of the heat exchanger and slagging in the combustion chamber, and the steam generator (boiler) becomes larger and requires an ash treatment device, so coal-fired had limited use. Therefore, a coal gasifier is installed to incompletely burn the coal, and the combustion chamber of the boiler itself uses the coal gas generated in the gasifier to burn gas. In this way, contamination and abrasion of the heat transfer surface in the heat exchanger section of the boiler can be minimized, and slagging of the combustion chamber due to ash can also be prevented.

[Problem to be solved by the invention]

Coal gasifiers are currently under development, but the main types are fluidized bed and spouted bed types. These systems supply coal in the form of fine powder, so in addition to air for oxygen for combustion, high-pressure air is required to fluidize the fine coal particles. It also required a high-performance mill to supply fine-sized coal particles and equipment to circulate the char.

In addition, in the past, SOX, NO! , denitrification equipment, desulfurization equipment when using coal gas containing a large amount of dust, etc.

It was necessary to install dust collectors, etc., and the investment amount was substantial. For this reason, there has been a demand for the development of a coal gasifier that processes all harmful components before inputting them into the steam generator.

(l [Means for Solving the Problems] In order to solve the above-mentioned 11 conventional problems, the present invention provides a gasifier body, a lattice provided in the gasifier body, and an original on the lattice. A raw coal hopper and a limestone hopper for supplying coal and limestone respectively, a means for supplying air below the grate, a produced gas discharge duct connected to the upper part of the gasifier main body, and a produced gas discharge duct connected to the upper part of the gasifier main body. A classifier installed at the inlet, a clinker hopper installed below the gasifier main body, a heat exchanger installed inside the clinker hopper, and ammonia water that has passed through the heat exchanger are transferred to the lattice. The present invention proposes a coal gasification and combustion apparatus characterized by comprising means for injecting the coal downward.

[For production]

In the coal gasification apparatus of the present invention, since fixed bed combustion is performed, raw coal having a relatively large coal particle size can be input. Therefore, the generation of soot and dust is suppressed and the gasification temperature is kept low to reduce NOx.

The generation of SOx can be reduced. At the bottom, the temperature rises to a certain degree to discharge the cinders after combustion, producing NOx.
, SOx is generated, but SOx is desulfurized in a dry manner by filling limestone with coal. NO
x is decomposed and denitrified by adding ammonia.

〔Example〕

The attached drawing is a conceptual diagram showing one embodiment of the present invention. In the drawing, (1) is a vertical cylindrical gasifier main body, and (2) is a gasifier provided in the gasifier main body (1). It is a lattice. (3) and (4) are a raw coal hopper and a limestone hopper that respectively supply raw coal and limestone onto the same grid (2).

(5) is an air duct connected below the grid (2).

(6) is a produced gas duct connected to the upper end of the gasifier main body (1), and (7) is a classifier provided at the entrance of the produced gas duct (6). CB) is a slag hopper provided below the gasifier main body (1), and QO) is a heat exchanger provided within the slag hopper (8). The inlet of the heat exchanger aω is connected to an ammonia water tank OD via an ammonia pump, and the outlet is connected to an ammonia nozzle provided in an air duct (5). In the figure, (b) is the auxiliary burner, (+5) is the boiler furnace, aω is the boiler furnace burner, 08), (FD
is a control valve.

In such a device, raw coal and limestone are fed onto the grid (2) from a raw coal hopper (3) and a limestone hopper (4). Further, combustion air is supplied from an air duct (5) to the bottom of the gasifier below the grid (2). Before starting gasification, the temperature inside the furnace is raised using an auxiliary burner ring. When stable gasification begins, this auxiliary burner (b) is extinguished.

The generated high-temperature coal gas is taken out from the upper end of the gasifier main body (1) and guided to the burner 051 of the boiler furnace 05) through the generated gas duct (6), where it is subjected to combustion.

In order to reduce the dust in the coal gas that carries over to the produced gas duct (6) and exits, the flow velocity at the top of the gasifier body is kept low, and the classifier (0 classifier (7) that feeds dust with a sword) is installed in the cone section. This applies centrifugal force to the gas flow as it turns.

After completion of combustion, the slag falls through the grate (2) into the slag hopper (8), where it is cooled with water and coarsely crushed by rapid cooling. The crusher (9) installed at the bottom of the slag hopper crushes the slag into finer particles, making it easier to process. The temperature of the water in the slag hopper (8) gradually rises due to the amount of heat from the high-temperature falling ash, and eventually reaches a boiling state. Using this amount of heat, heat exchange is performed in the heat exchanger 00).

The fuel (coal) near the grid (2) is undergoing oxidative combustion, and it is expected that SO and NOx will be produced in this area. SOx is removed by dry method by adding limestone together with coal. Regarding NOx, high-temperature non-catalytic denitrification is performed by adding ammonia. In other words, ammonia water is supplied by the ammonia pump α force from the JD, and is heated in the heat exchanger 00 above, so that the ammonia evaporates easily. become. Since the ammonia that is blown into the air duct (5) from the ammonia nozzle 0 needs only a pp- concentration, it needs to be sufficiently diffused and mixed with the combustion air. Therefore, in this embodiment, an ammonia nozzle 031 of a pressure spray type or an air or steam spray type is provided in the air duct (5) to achieve rapid evaporation and diffusion, thereby shortening the distance required for diffusion with the air. I am hiding it. Conventionally, ammonia was supplied in a liquefied state, so the storage tank was treated as a dangerous substance and could not be installed near the boiler, but in this example, ammonia water is used, so it is safe.

The feature of the coal gasification combustion in this example is that the gasification is performed using the heat generated by partially oxidized combustion, and the coal and limestone packed bed in the gasifier plays an important role. Control of the internal coal seam is performed by detecting pressure loss within the bed. 0'7) is the intralayer pressure loss line,
The control pulp for coal 08) and the control pulp for limestone 09) are supplied with a signal with a value set so as to obtain the optimum condition.
The ratio of limestone to coal is determined by the sulfur content in the coal.

In this example, raw coal having a relatively large coal particle size is used as the raw material. When raw coal is used in the conventional gasification method, the coal lumps fall into the water in the slag hopper below without finishing burning, and gasification is not completed. In this example, a fixed bed was used. Therefore, raw coal with a large particle size can be used, so the generation of soot and dust is suppressed, the gasification temperature is kept low, and the amount of NOx and SOx generated is also reduced.

〔Effect of the invention〕

According to the present invention, all kinds of coal from anthracite to lignite can be used as fuel, and existing heavy oil-fired or gas-fired boilers can be easily converted into coal-fired boilers. Moreover, as a low-pollution coal-fired boiler, the flue gas desulfurization equipment, desulfurization equipment, and dust collection equipment that were always installed in conventional coal-fired boilers are no longer necessary or the capacity has been reduced, achieving a significant cost reduction. can do.

[Brief explanation of the drawing]

The accompanying drawings are conceptual diagrams illustrating one embodiment of the present invention. (1)...Gasifier body, (2)...Grate. (3) Raw coal hopper, (4) Limestone hopper. (5)...air duct), (6)...generated gas duct. (7)...Classifier, (8)...Slag hopper (9)
...Crusher, 0[D...Heat exchanger. 01)...Ammonia water tank. Side...Ammonia pump. 03)...Ammonia nozzle, (2)...Auxiliary burner 05)...Boiler furnace, 06)...Burner 07)...Intralayer pressure loss lines 010, 09)...Control pulp. 4 limestone hopper

Claims (1)

[Claims] A gasifier main body, a grid provided in the gasifier main body, a raw coal hopper and a limestone hopper that respectively supply raw coal and limestone onto the grid, and means for supplying air below the grid. , a produced gas discharge duct connected to the upper part of the gasifier main body, a classifier provided at the entrance of the produced gas discharge duct, a clinker hopper provided below the gasifier main body, and the clinker hopper provided below the gasifier main body. A coal gasification apparatus comprising: a heat exchanger provided in a hopper; and means for injecting ammonia water that has passed through the heat exchanger below the grid.