RU2415337C1 - Operating method of boiler in bottom-ash removal mode - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: in boiler operating method in bottom-ash removal mode, which involves combustion of solid fuel in high-temperature circulating fluidised bed, the bottom ash is removed from combustion zone to slag receiving zone, combustion products are removed and heat the primary air, slag contacting with the coil installed in slag receiving zone heats the ambient air moving in the coil and directed to combustion zone as secondary air.

EFFECT: improving reliability and economy by simplifying the slag removal at available ash hopper and utilisation of heat of slag during steam generation in case of combustion of solid fuel in high-temperature circulating fluidised bed and removal of slag in solid form.

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Description

The invention relates to a power system and can be used in steam boilers burning solid fuel in a high-temperature circulating fluidized bed while removing solid slag.

A known method of organizing a furnace process, including the burning of solid fuel, the removal of solid slag from the combustion zone to the reception zone of solid slag and removal of combustion products from the combustion zone (Reznikov MI, Lipov Yu.M. Boiler plants of power plants. - M.: Energoatomizdat , 1987, p. 108, fig. 8.13).

The disadvantage of this method is the deterioration of slag removal due to sintering of slag particles at low heat loads (less than 70%). Another disadvantage is the high losses with the physical heat of the slag output at a high temperature, which reduces the efficiency of the firing process under conditions of steam generation and increases the consumption of combustible fuel.

Thus, the lack of heat recovery of the output slag reduces the efficiency of the combustion process carried out by this method.

The technical result of the proposed method is to increase reliability and efficiency by facilitating the removal of slag by increasing the effect of a cold funnel and utilizing the heat of slag during steam production in the case of burning solid fuel in a high-temperature circulating fluidized bed and removing slag in solid form.

The specified technical result is achieved by the fact that in the method of operation of the boiler in solid slag removal mode, including burning solid fuel in a high-temperature circulating fluidized bed, removing slag from the combustion zone to the slag receiving zone, removing combustion products and heating the primary blast air with them, in the solid receiving zone a slag is installed in a coil in which atmospheric air is directed to the combustion zone as a secondary blast.

The presence of a cold funnel in the lower part of the furnace volume of the boiler, formed by converging the screens or the walls of the furnace with a large slope, can reduce the temperature in the lower part of the furnace. Falling molten slag particles falling into this zone quickly solidify from the outside and slide into the slag receiving zone.

Slag particles have a temperature of up to 1000 ° C, in contact with a coil installed in the slag receiving zone, heat the atmospheric air moving along the coil to 200-260 ° C. Then, heated air is supplied as a secondary blast to the combustion zone of the boiler.

The temperature in the combustion zone when burning solid fuel in a high-temperature layer reaches 1600-1800 ° C. At the injection site of the secondary blast, the layer temperature is maximum.

Upon contact with the coil, the temperature of the slag decreases significantly, increasing the effect of the cold funnel, therefore, the possibility of sintering and sticking of particles of slag to the boiler elements is minimized, which increases the reliability of the boiler according to the claimed method.

The high temperature of the exhaust gases formed during the combustion of solid fuel after superheaters reaches 750 ° C and is used to heat the primary blast air, which is fed under the grate with a temperature of up to 260-300 ° C. In the presence of an economizer, the temperature of the exhaust gases after it reaches 350-400 ° C, in this case, the air heater will provide air heating to 180-260 ° C.

The essence of the proposed method is illustrated in the drawing.

Fuel 1, combustion zone 2, slag stream 3, slag receiving zone 4, coil 5, secondary blast nozzles 6, combustion products stream 7, grate 8.

The method is as follows.

When fuel 1 is burned in the combustion zone 2, slag 3 is formed. From the combustion zone, the slag stream enters the reception zone of slag 4. In the reception zone of slag, secondary blast air moves along the coil 5, taking heat from the slag. Next, the heated air is fed into the furnace through the nozzles of the secondary blast 6. The flow of combustion products 7 heats the primary blast air supplied under the grate 8.

Thus, the proposed method, in comparison with the known method, can improve reliability and economy by installing a coil in the slag receiving zone, increasing the effect of a cold funnel, which improves the conditions for the solidification of slag particles and removal of slag from the combustion zone, as well as utilizing slag heat in the inventive method burning solid fuel in a high temperature circulating fluidized bed and removing solid slag.

Claims (1)

The method of operation of the boiler in solid slag removal mode by burning solid fuel, withdrawing solid slag from the combustion zone to the slag receiving zone, removing combustion products and heating the air sent to the combustion zone as an oxidizing agent, characterized in that the slag is in contact with the slag installed in the zone receiving slag by the coil heats the atmospheric air moving along the coil and sent to the combustion zone as a secondary blast.

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