RU182137U1 - Fluidized bed solid fuel boiler - Google Patents

Abstract

The claimed technical device relates to the field of power engineering. The technical result of the claimed utility model is to improve the characteristics of combustion processes. The boiler unit consists of a mechanical furnace device in the form of a movable grate (1) inclined to the horizon for burning solid fuel in a high-temperature fluidized bed, heating surfaces, feeder fuel ejector. Fuel is supplied by a screw type feeder (8) to an inclined plate (7) and then to the furnace of the boiler unit. Screen heating surfaces are steel, gas-tight, water-tube screens. Convective heating surfaces made in the form of two water-tube sections (5) and (9), which provide a turn of gases in a vertical plane and the deposition of unburned fuel particles and fly ash contained in gases in an ablation recovery hopper with an ejector. Two-stage air supply is provided: under the grate through the blast zones of the primary blast (2) and into the superlayer space through the slotted nozzles of the secondary blast (3). Using the ejector, the ablation (12) is returned to the combustion chamber for afterburning. Air in the primary blast zones is supplied under the grill through a bent pipe in the vertical direction. Air into the secondary blast zone is supplied through slotted nozzles arranged in a checkerboard pattern. The exhaust gas from the pressure line of the exhaust fan is mixed into the suction line of the blower fan of the boiler unit. An additional tube section (4) is included in the superlattice heating surface. The installation on the side wall of the lining of the combustion device of the starting burner (15) on diesel fuel was applied, directed towards the zone of active combustion of fuel in a fluidized bed above the grate. A telescopic device (16) is installed in the rear wall of the boiler for knocking slag from the grate over the zones of primary air. 3 ill.

Description

The utility model relates to the field of heat power engineering.

The prototype is a boiler for burning coal [Smirnov A.V. and others. A boiler unit for the combustion of coal in a fluidized bed. Utility Model Patent. Registered in the State Register of Utility Models of the Russian Federation on May 20, 2004 No. 38041, bull. No. 14] [1], consisting of a mechanical furnace device in the form of a narrow movable grate for inclination of fuel to the horizon in a high-temperature fluidized bed, heating surfaces, fuel feeder, ejector. The heating surfaces have gas tight screens that provide a gas turn to organize the ablation return system. Air is supplied under the grate and into the superlayer space, in the combustion chamber along the grate there is an additional heating surface included in the boiler circulation circuit.

This analogue has several disadvantages:

1. The unevenness (portioning) of the fuel supply with a scraper feeder, which violates the stability of combustion and temperature conditions in static mode and the quality of transients in dynamic modes;

2. The combustion regime is violated with increasing temperature and subsequent slagging of the lattice. In particular, when the coefficient of excess air increases, the temperature in the furnace increases, and as a result, favorable conditions are created for slagging of the boiler grate;

3. The air supply under the grate does not ensure its movement in a direction strictly perpendicular to the grate. With the existing air supply scheme, the flow is shifted towards the furnace wall opposite to the side of the duct inlet ducts. The above circumstance leads to crater burning of fuel in a fluidized bed and uneven thermal stress of the volume of the combustion chamber;

4. The underestimated area of the superlattice (submersible) heating surfaces does not provide optimal heat removal from the fluidized bed, which reduces the efficiency of the boiler;

5. The supply of secondary air to the superlayer space through nozzles of circular cross section does not effectively reduce the entrainment of small fractions of fuel from the fluidized bed into the superlayer space.

An analogue is a boiler for burning coal [Smirnov A.V. and others. A boiler unit for the combustion of coal in a fluidized bed. Utility Model Patent. Registered in the State Register of Utility Models of the Russian Federation 05.05.2017, No. 170747, bull. No. 13] [2], consisting of a mechanical furnace device in the form of a movable grate for tilting the solid fuel in a high-temperature fluidized bed with air supply under the grate and into the allotment space, heating surfaces in the form of gas-tight screens, providing gas reversal for organizing ablation return system, fuel feeder, ejector, additional heating surface along the grate included in the circulation circuit of the boiler, characterized in that the fuel feeder is made in the form Nek, primary air duct in the area under the grate blast is bent to a vertical position, the secondary duct in the zones of the blast is in the form of slotted nozzles, boiler blow fan suction passage is connected to the pressure line exhauster for admixing flue gas into the additional heating surface is enabled nadreshetochnuyu tubular section.

This analogue has several disadvantages:

1. In some modes, with increasing layer temperature, the combustion mode is violated, and conditions are created for slagging the grate of the boiler unit;

2. The supply of secondary air occurs on the same plane opposite each other in the superlayer space of the furnace, which leads to the entrainment of small fractions of fuel from the fluidized bed into the superlayer space;

3. The lack of automatic kindling of the furnace after the complete cessation of its operation in the event of a long stop and cooling for repair or preservation of the boiler, or during a short stop and cooling during a temporary shutdown of thermal energy consumers;

4. There is no possibility of switching to a reserve type of fuel in the absence of the main one, which reduces the reliability of heat supply to consumers;

The disadvantages of the prototype set the task of the utility model:

- maintaining the stability and temperature of combustion in static modes, improving the quality of transients in dynamic modes, increasing the automation level of the boiler and increasing the reliability of heat supply to consumers of thermal energy.

The essence of the claimed utility model consists in the fact that a boiler for burning solid fuel in a fluidized bed, consisting of a mechanical furnace device in the form of a movable grate, inclined to the horizon, for burning solid fuel in a high temperature fluidized bed with air supply under the grill and in the superlayer space, surfaces heating in the form of gas tight screens, providing a gas turn for the organization of the ablation return system, a fuel feeder made in the form of a screw, ejector, additional heating surface along the grate included in the circulation circuit of the boiler, the duct located under the grate in the primary blast zone bent to a vertical position, the duct in the secondary blast zones made in the form of slotted nozzles, the suction line of the blower fan of the boiler, connected to the discharge line of the smoke exhauster for mixing the exhaust gases , an additional pipe section included in the superlattice heating surface, characterized in that the slotted nozzles of the secondary blast are located in a staggered oryadke, in the combustion device on the side wall brickwork launcher installed on diesel fuel burner directed towards the active zone of fuel combustion in a fluidized bed above the grate in the rear wall of the boiler installed telescopic device for knocking down slag from grate zones of primary air.

The technical result of the claimed utility model is to improve the characteristics of combustion processes.

Improving the characteristics of the combustion processes of the boiler for burning solid fuel in a fluidized bed is achieved due to the fact that:

1. The use of slotted nozzles in the secondary blasting zone, arranged in a checkerboard pattern, allows you to create a denser curtain of small fractions of fuel, which leads to a decrease in fuel losses, and as a result, heat losses from mechanical incompleteness of combustion with entrainment;

2. The use of a telescopic device located in the furnace allows slag churning over the first blast zone of the grate. This solution reduces the slagging of the grate and prevents the formation of crater burning.

3. Installing the start-up burner device from the side provides the kindling of the boiler unit in automatic mode and provides the possibility of the boiler unit operating on liquid and solid fuel. Allows installation of a starting burner on diesel fuel, without changing the design decisions of the boiler.

The proposed design of the boiler is illustrated by drawings. In FIG. 1 shows a section of a boiler unit - side view. In FIG. 2 section of the boiler - front view. In FIG. 3 shows a section of a boiler unit - top view.

The boiler unit includes a mechanical furnace device, heating surfaces, a screw type fuel feeder, an ablation return hopper and an ejector. The main technological element of the furnace is a movable, grated forward grate (1). This device also includes a frame with an air box located inside it, divided into primary zones of blasting (2), as well as side and transverse (interzone) seals. The air duct in the secondary blast zones is made in the form of slotted nozzles arranged in a checkerboard pattern (3). To control the temperature level in the fluidized bed along the grate, a heating surface is installed, included in the circulation circuit of the boiler with an additional pipe section (4), which is a cooling panel.

The furnace is bounded on the sides and top by steel gas-tight water-tube sections (5). Fuel is supplied to the forward grate from the fuel hopper (6) via an inclined plate (7) using a screw type fuel feeder (8). The boiler unit also contains a water pipe section (9), a heat-resistant steel partition (10) between the water pipe sections (5) and (9), an ablation return hopper (I) with an ablation return ejector (12), a flue gas recirculation line (13), a rotary circular gate (14), starting torch (15), telescopic device (16).

The claimed device works as follows:

Part of the air is directed under the grate (1) through the primary air blast zones (2), and the other into the superlayer space through the slotted nozzles of the secondary blast (3), staggered.

The following scheme of gas movement is organized in the boiler unit. Gases rise from the straight-through grate to the upper part of the furnace, pass down a series of parallel pipes of the water pipe section (5), turn 180 ° and, passing up the water pipe section (9), are removed from the boiler unit. To ensure the flue gas turn between the water tube sections (5) and (9), a partition made of heat-resistant steel (10) is installed. A sharp turn of the gases allows the unburnt particles of fuel and fly ash removed from the furnace to be deposited in the ablation recovery hopper (11) and returned to the afterburning furnace using the ejector (12).

When slag is formed in the gaps of the grate, the telescopic device (16) is activated, which, when moving along the grate to the first blast zone, knocks the slag.

When the boiler unit starts up, the start-up burner (15) is switched on for diesel fuel directed at an angle to the side of active fuel combustion in a fluidized bed above the grate. After igniting the boiler, the burner shuts off.

The proposed design of the boiler unit is not identified from the existing level of development of technology, namely:

- reduces the formation of slag;

- prevents the formation of crater burning;

- reduction of fuel losses with the entrainment of fuel particles;

- reduction of heat loss from mechanical incompleteness of combustion;

- the ability to kindle the boiler in automatic mode;

- operation of the boiler on liquid and solid fuels.

This allows us to conclude that it meets the criterion of "novelty."

The implementation of the claimed device does not present any technological, structural and technical difficulties, hence the compliance with the criterion of "industrial applicability".

List of sources used

1. Smirnov A.V. and others. A boiler unit for the combustion of coal in a fluidized bed. Utility Model Patent. Registered in the State Register of Utility Models of the Russian Federation on May 20, 2004 No. 38041, bull. No. 14 is a prototype.

2. Smirnov A.V. and others. A boiler unit for the combustion of coal in a fluidized bed. Utility Model Patent. Registered in the State Register of Utility Models of the Russian Federation 05.05.2017, No. 170747, bull. No. 13 is an analogue.

Claims (1)

A boiler for burning solid fuel in a fluidized bed, consisting of a mechanical furnace device in the form of a movable grate for tilting solid fuel, inclined to the horizon, for burning solid fuel in a high temperature fluidized bed with air supply under the grill and in the superlayer space, heating surfaces in the form of gas-tight screens providing a gas turn for organizing an ablation return system, a fuel feeder made in the form of a screw, an ejector, an additional heating surface along a grate included in the circuit the boiler duct, the duct located under the grill in the primary blast zone bent to a vertical position, the duct in the secondary blast zones made in the form of slotted nozzles, the suction line of the blower fan of the boiler, connected to the discharge line of the smoke exhauster for mixing the exhaust gases, with an additional pipe section included in the superlattice heating surface, characterized in that the slotted nozzles of the secondary blasting are staggered in the furnace device on the side wall of the fouling A diesel-fired start-up burner was installed, directed towards the zone of active fuel combustion in a fluidized bed above the grate; a telescopic device was installed in the rear wall of the boiler to knock slag from the grate above the primary air zones.

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