RU170747U1 - Fluidized bed solid fuel boiler - Google Patents

Abstract

The utility model relates to the field of heat power engineering. The boiler unit consists of a mechanical furnace device in the form of a narrow, mobile, grate-mounted grate for burning solid fuel in a high-temperature fluidized bed, heating surfaces, fuel feeder, ejector, with heating surfaces in the form of gas-tight screens. Fuel is supplied by a screw type feeder onto an inclined plate and further into the boiler furnace. Screen heating surfaces are steel gas-tight water-tube screens. Convective heating surfaces are made in the form of two gas pipe sections, which provide a turn of the gases in a vertical plane and the deposition of unburned particles of fuel and fly ash in the gases in the flyback hopper with an ejector. A two-stage air supply was used: under the grate through the blast zones of primary air and into the superlayer space through nozzles of the secondary blast. Using the ejector, the ablation is returned to the furnace for afterburning. Air in the primary blast zones is supplied under the grill through a bent pipe in the vertical direction. Secondary air is supplied to the superlayer space through slotted nozzles, exhaust gases from the pressure line of the smoke exhauster are mixed into the suction line of the boiler blower fan. An additional tube section is included in the additional superlattice heating surface.

Description

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

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

Known 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], consisting of a mechanical furnace device in the form of a narrow movable grate for inclining the horizon to burn fuel 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.

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

- maintaining the stability and temperature of combustion in static modes and improving the quality of transients in dynamic modes.

The essence of the claimed utility model consists in the fact that the boiler for burning solid fuel in a fluidized bed, consisting of a mechanical furnace device in the form of a movable grate, which is inclined to the horizon, further, a grate 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 turn of gases for organizing an ablation return system, fuel feeder, ejector, additional surface on roar along the lattice included in the boiler circuit. The fuel feeder is made in the form of a screw. The duct in the primary blast zone under the grill is bent to a vertical position, the duct in the secondary blast zones is made in the form of slotted nozzles. The suction line of the blower fan of the boiler is connected to the pressure line of the exhaust fan to mix the flue gases. An additional superlattice heating surface includes a tube section.

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 fuel feeder is made in the form of a screw, which provides a uniform (non-proportional) feed and does not violate the stability of combustion and temperature conditions in static modes and the quality of transients in dynamic modes.

2. The use on the suction line of the blower fan of the boiler, connected to the pressure line of the exhaust fan, allows the flue gas to be mixed. This decision is due to the fact that in some cases, for example, with a decrease in fuel consumption, the coefficient of excess air sharply increases, which leads to an increase in temperature in the furnace and slagging of the grate. To prevent the temperature increase in the furnace and further slagging, the flue gases are mixed with the air going to combustion. This leads to a decrease in the concentration of oxygen in the mixture and the establishment of the optimum temperature at which slagging does not occur.

3. The use of a duct bent to a vertical position in the primary blast zone under the movable grate prevents the air flow from moving to the side and crater burning;

4. An additional tube section has been added to the superlattice heating surface. This allows you to achieve optimal heat removal from the fluidized bed.

5. The use of the duct in the secondary blast zones, made in the form of slotted nozzles, allows you to create a denser curtain of small fractions of fuel, compared with nozzles of circular cross section. This solution leads to a decrease in fuel losses and, as a consequence, heat losses from mechanical incompleteness of combustion with entrainment.

The proposed boiler design is not identified from the existing level of technology. 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".

The proposed design of the boiler is illustrated by drawings. In FIG. 1 shows a section through the boiler, a side view. In FIG. 2 section of the boiler - front view. The boiler 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 (3). To control the temperature level in the fluidized bed along the grate, a heating surface is installed, which is included in the boiler circuit 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 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 (11) with an ablation return ejector (12), a flue gas recirculation line (13), a rotary round gate (14).

The claimed device operates 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 secondary blast slotted nozzles (3).

The following gas movement pattern is organized in the boiler. Gases rise from the straight-through grate to the top of the furnace, pass down a series of parallel pipes of the water tube section (5), turn 180 ° and, passing up the water tube section (9), are removed from the boiler. 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).

Shown in FIG. 2 section of the boiler, front view, made from the side of the fuel feeder. In the boiler, the flue gas is mixed to the suction line of the blower fan from the pressure line of the exhaust fan. In the exhaust gas recirculation system (13), a shut-off and regulating body is provided - a rotary gate of circular cross-section (14).

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. It is registered in the State register of utility models of the Russian Federation on May 20, 2004, No. 38041, bull. Number 14.

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, an ejector, an additional heating surface along the grate included in the boiler circulation circuit, distinguishing I mean that the fuel feeder is made in the form of a screw, the air duct in the primary blast zone under the grill is bent to a vertical position, the air duct in the secondary blast zones is made in the form of slotted nozzles, the suction line of the boiler blower fan is connected to the pressure line of the exhaust fan to mix the exhaust gases, An additional superlattice heating surface is included in the tube section.

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