RU2006739C1 - Heat recovery device - Google Patents

Abstract

FIELD: power engineering. SUBSTANCE: combustion products enter gas flue 7 where they pass in succession through surface heat exchanger 5, contact chamber 10 with water spraying device 16 and filtering checker 9 and condensing surface 6. Arranged inside checker 9 is sprinkler 15. Water receiver 4 is located under above-mentioned members. Side walls of water receiver and heat-exchange elements of condensing surface 6 are inclined to horizontal plane. Ash separated from gas flow settles in water receiver 4 and is carried to ash discharge branch pipe by means of screw conveyer 2. Water receiver 4 is connected to sprinkler 15 of checker 9 and to water spraying device 16. EFFECT: enhanced efficiency. 1 dwg

Description

 The invention relates to boiler equipment, where solid fuel is burned.

 A device for heat recovery of exhaust gases, consisting of several parallel-connected heat exchangers, the lower part of which is designed to discharge and sludge condensate, and the upper one to remove exhaust gas and supply water of an intermediate liquid medium to the irrigation device, as well as from a smoke exhauster and chimney [1] .

 A known installation of heat recovery of combustion products, containing a flue with sequentially installed in it along the gas evaporator, combined with a sprinkler, condenser and aftercooler, additionally connected to the chimney [2].

 A known heat exchanger having sprinklers in the duct located at the bottom and top of the heat exchange surface, a moisture collector connected to these sprinklers through a surface heat exchanger, cooled by part of the water entering the heat exchange surface [3].

 Known utilization installation, including in the direction of the combustion products, an overheat heat exchanger, an evaporation chamber, a condensation heat exchanger, water inlet and outlet pipelines, a separation grid connected to the gas duct through the overheat heat exchanger with a chimney [4].

The products of combustion temperature approximately equal to 250 ^{° C} is heated in the heat exchanger superheat waste gases after recovering apparatus. This overheating eliminates moisture condensation on the surfaces of the duct and chimney.

 After the heat exchanger overheats, the combustion products enter the evaporator, in which they are saturated and cooled by condensate falling from the condensation part of the heat exchanger. Condensation of water vapor from a gas-vapor mixture is accompanied by the release of latent heat of vaporization due to the use of cold water as a heated medium. Then, the cooled flue gases pass through the separator and enter the overheating heat exchanger. The normal operation of the considered heat recovery installation when burning solid fuel is difficult. The fly ash, which is part of the combustion products, in contact with the condensate in the volume, on the heat exchange surface and the wall is moistened and gradually sticks. As a result, after a certain period of time there is a sharp deterioration in the heat transfer process, as well as a decrease in the cross section for the passage of combustion products between the heat exchange elements and in the separator. In addition, an increase in aerodynamic drag entails an increased energy consumption for driving a smoke exhaust.

 The technical result is achieved by the fact that the heat recovery device is equipped with a water spray device, a filter nozzle with a sprinkler inside, a screw, a circulation pipe with a pump and an ash outlet, and the water spray device and filter nozzle are sequentially placed along the gases in the contact chamber, the side walls of the water collector and heat exchange elements inclined to the horizontal plane, the screw is located in the bottom of the catchment basin, the next one is connected via a pipeline to the sprinkler th filter nozzle and water spray device, and the ash outlet pipe is connected to the bottom.

 The drawing shows a heat recovery device.

 It contains a boiler unit furnace 1, a screw feeder 2, a gas tight loop 3, a pallet 4, convective and condensation stages 5, 6, a housing 7, an interstage partition 8, nozzles 9, an evaporation chamber 10, a blower fan 11, a smoke exhauster 12, a pump 13, a smoke pipe 14, washer and irrigation apparatus 15, 16, overflow 17, inclined wall 18, make-up pipe 19, axis of the heat exchange element, 20, fittings, 21, 22, 23.

 The type of combustion chamber is determined by the specific type of boiler.

 The screw feeder 2 is selected depending on the required capacity and the required pressure for transporting the ash emulsion through the gas tight loop 3 to the combustion chamber.

 Pallet 4 is made of sheet iron. It has an inclined side wall 18, which in its lower part passes into the pit necessary to accommodate the screw feeder 2. In addition, the pump intake device 13 and overflow 17 are placed in it.

The surface area of the heat exchanger, the number of rows, the number of pipes in a row and other indicators of the convective and condensation stages are determined by the heat engineering calculation. In the condensation stage, the axes of the heat exchange elements 20 are inclined at an angle α, which is approximately equal to 5-8 ^about , to the axis of the horizontal plane.

 The housing 7 of the heat recovery device is sheathed with steel sheet, and is also insulated from the outside (thermal insulation is not shown in the drawing). The convective 5 and condensation 6 steps located in it are separated by an interstage partition 8. It is in the lower part that is joined with the nozzle 9, which consists of a layer of Raschig rings in which the washer 15 is installed.

 The volume limited by the convective step 5, the interstage partition 8 and the upper water level in the pan relates to the evaporation chamber 10. At the top there is an irrigation device 16. The irrigation 16 and the washing device 16 are equipped with devices (not shown) that spray water into the surrounding space of the evaporation chamber 10 and the nozzle 9. The flushing 15 irrigation 16 devices are connected by pipelines to the water intake from the tray 4 and the make-up pipe 19. Water is supplied by the pump 13. Water flow, required Irrigation in the evaporation chamber 10 and the flushing nozzle 9 is determined on the basis of calculations for cleaning the combustion products from the ash component.

 The proposed heat recovery device operates as follows.

The combustion products coming from a temperature approximately equal to 250 ^{° C,} cooled in a convection stage to a temperature of the dew point of sulfuric acid, which corresponds to approximately 110 ^C. In the vaporization chamber 10 the exhaust gases pass through the water curtain created by irrigation device 16. Gold ash is wetted and it is washed off in the pallet 4. The cleared, moistened and cooled to about 70.. . 80 ^C. products of combustion pass through the orifice 9. It occurs more filtering exhaust gases from the ash component which is periodically washed with the washing apparatus 15. In the steam-gas mixture at a volume between nozzle passage 9 and the condensation stage 6 embryos condensation formed that grow as they approach to the last. On the heat exchange elements of the condensation stage, water vapor is condensed from the vapor-gas mixture. The condensate flows downhill at an angle α = 5.. . 8 ^{about the} heat exchange elements on the vertical wall of the housing, and then into the tray 4 through nozzles 9. Chilled to about 20.. . 30 ^° C at the exit of the condensation stage 6 are removed into the chimney 14 with a moisture content lower than at the entrance to the convective stage 5, since the air pumped by the fan 11 has an ambient temperature.

 The wetted ash flows down the inclined wall 18 into the screw feeder 2, which transports the waterlogged ash through a gas tight loop to the furnace of the boiler unit. Water is supplied to the flushing 15 and irrigation 16 devices by the pump 13. The excess water in the sump 4 is removed through the overflow 17, and its deficiency is filled up from the make-up pipe 19.

 Thanks to the use of the proposed heat recovery device: 1. The emission of ash, unburned fuel and sulfuric acid into the atmosphere is eliminated; 2. increases the efficiency of the boiler plant due to the return to the afterburning of the mechanical entrainment of fuel and the beneficial use of low-grade heat of combustion products; 3. The aerodynamic drag of the condensation stage is reduced, since condensate flows down the body wall; 4. increases the heat transfer coefficient of the condensation stage by reducing the thickness of the condensate water film on the heat exchange surface. (56) Patent GDR N 156197, cl. F 28 D 3/00, 1982.

 USSR author's certificate N 989232, cl. F 22 B 1/18, 1983.

 USSR author's certificate N 135719, cl. F 22 B 1/18, 1987.

 USSR author's certificate N 1615453, cl. F 22 B 1/18, 1990.

Claims (1)

 HEAT RECOVERY DEVICE containing a surface heat exchanger sequentially placed in the gas duct, a contact chamber and a condensation surface in the form of heat exchange elements with side walls adjacent to the bottom formed by adjoining bottoms, characterized in that it is equipped with a water-spraying device, a filter nozzle with an irrigator inside, a screw a circulation pipe with a pump and an ash outlet, the water spray device and filter nozzle therefore placed along the gas in the contact chamber, the side walls sump and the heat exchange elements are inclined to the horizontal plane, the screw is placed in the bottom of the sump and the latter by means of said conduit is connected to sprinkler nozzles and vodorazbrazgivayuschemu filtering device and ash discharge conduit connected to the bottom.