RU51177U1 - SOLID FUEL COMBUSTION DEVICE - Google Patents

Abstract

A device for burning solid fuel relates to a power system, and can be used in the manufacture of steam and hot water boilers. The device includes a firebox, laterally bounded by water-tube heat exchanger screens connected to the corresponding horizontal upper and lower collectors, a fuel hopper with a conical (in plan) bottom and an outlet made therein, a fuel dispenser, an inclined feeder connected to one side of the fuel hopper, an inclined a grill with transverse air gaps formed by metal plates mounted with overlap, a chamber for burning volatile substances in communication with the furnace, the primary duct o blast connected to the fan and ash trap located at the bottom of the furnace. In order to simplify the design, increase the service life and improve the environmental safety of the device, the rear wall and the upper part of the front wall of the furnace are also formed by water tube heat exchanger screens connected from the bottom and top to the corresponding horizontal collectors, the fuel hopper is placed above the inclined feeder in front of the front screen so that it the conical bottom is located under the lower edge of the latter, the beveled bottom wall faces the furnace space and is tightly connected to the front screen with an image the lower part of the front wall of the furnace, and the space between the sloping wall of the bottom of the hopper and the working surface of the inclined feeder is the base of the chamber for burning volatile substances, the inclined feeder, grate, and ash collector are made up of water-cooled pipes installed with a gap relative to each other and connected, respectively, to the additional horizontal collector and the lower rear screen collector, while the gaps between the water-cooled pipes of the inclined feeder and the side wall ash and slag trays are tightly sealed with spacers, metal plates to the water-cooled tubes of the grate are welded at an angle of 35-40 ° to the horizontal plane at a distance of 5-10 mm from each other with the formation of slit-like nozzles facing the lower (along the fuel) part of the grate, the angle of the feeder and the lattice to the horizontal plane is 45-55 °, an additional horizontal collector is connected bypass

a pipe with a lower horizontal collector of the front screen, and the furnace is additionally equipped with pipelines of secondary and additional blasting, respectively, located above the inclined grate in the combustion zone and under the grate of the ash and slag trap and connected to the fan.

Description

The utility model relates to a power system, namely, to devices for burning solid fuel and can be used in hot water and steam boilers.

A device for burning solid fuel is known, including a furnace limited by water-tube heat-exchange panels in communication with the corresponding upper and lower collectors, a fuel hopper, an inclined feeder, and a grate equipped with vibrators. See SU, No. 1592667, 04/03/87.

In the known device, the grate is an expensive bulky cast iron construction, laborious to manufacture. In addition, due to the constant exposure to high temperatures during the combustion of coal on it, the life of the grate is short. It should also be noted that in order to avoid sintering of coal and slagging of the grate, as well as to move fuel along it, the grate is equipped with vibrators, which complicates the device. In addition, the presence of moving mechanisms always reduces the reliability of the device.

The disadvantage of this device is also the high content of harmful volatile substances in flue gases.

Also known is a device for burning solid fuel, closest to the claimed technical essence (prototype). See RU, 2202733 C2, 07.27.2000.

The known device includes a furnace, limited laterally by water-tube heat exchanger screens connected to the corresponding upper and lower collectors, a fuel hopper with a conical bottom and an outlet made therein, an inclined feeder mated on one side with the fuel hopper, an inclined grate with transverse air gaps formed metal plates installed with overlap, a chamber for burning volatile substances in communication with the furnace, a primary air duct connected to the valve a torus and an ash trap located in the lower (along the course of the fuel) part of the furnace.

In the known device there is a chamber for burning volatile substances, connected to the housing of the screw feeder, which allows burnout of chemical volatile substances before feeding the fuel to the grate, thereby eliminating chemical underburning. However, the said chamber is made in the form of a confuser facing the center of the furnace with slots for supplying combustion air, which occurs between the pieces of fuel in the space enclosed by the walls of the confuser. Moreover, the temperature in the chamber reaches up to 1600 ° C. At this temperature, nitrogen oxides NO _x are intensively formed, which enter the atmosphere with flue gases, which is, in essence, more harmful than chemical underburning.

In the known device, the inclined grate is made of steel plates and is much simpler than the cast iron grate and more durable, however, without a special cooling system, its service life is insufficient. In addition, the angle of inclination of the lattice is 2-20 °, which is significantly lower than the angle of repose of the fuel, and vibrators with a drive are additionally installed to ensure the movement of fuel on the lattice and prevent its slagging. This complicates the device and reduces the reliability of its operation, due to the presence of additional moving mechanisms. It should also be noted that in the known device, the fuel hopper is located below the level of the grate under the feeder, and a screw conveyor with a drive is used as a feeder and fuel dispenser. This complicates and increases the cost of the device. In addition, as noted above, the presence of moving nodes reduces the reliability of the device.

The objective of the utility model is to create a simple in design, durable and environmentally friendly device.

This problem is solved by the fact that in the known device, including a furnace, laterally bounded by water tube heat exchanger screens connected to the respective horizontal upper and lower headers, a fuel hopper with a conical bottom and an outlet made therein, a fuel dispenser, an inclined feeder connected to one side with a fuel hopper, an inclined grate with transverse air gaps formed by metal plates installed with overlap, a chamber for burning out volatile substances, with generalized with the furnace, the primary blast duct connected to the fan and ash collector located at the bottom of the furnace,

according to a utility model, the rear wall and the upper part of the front wall of the furnace are also formed by water tube heat exchanger screens connected from the bottom and top to the corresponding horizontal collectors, the fuel hopper is placed above the inclined feeder in front of the front screen so that its conical bottom is under the lower edge of the latter, the beveled wall the bottom faces the furnace space and is tightly connected to the front screen to form the lower part of the front wall of the furnace, and the space between the beveled wall the bottom of the hopper and the working surface of the inclined feeder is the base of the chamber for burning out volatile substances, the inclined feeder, grate and ash trap are made up of water-cooled pipes installed with a gap relative to each other and connected, respectively, to the additional horizontal collector and lower collector of the rear screen the gaps between the water-cooled pipes of the inclined feeder and the side wall of the ash and slag trap are tightly covered by spacers, metal plates s to the water-cooled tubes of the grate are welded at an angle to the horizontal plane with the formation of slit-like nozzles facing the lower (along the fuel) side of the grate, the angle of inclination of the feeder and grate to the horizontal plane is 45-55 °, an additional horizontal collector is connected to the lower horizontal bypass pipe a front screen collector, and the furnace is additionally equipped with secondary and additional blast pipelines located, respectively, above the inclined grate in the combustion zone and under the grate koulovitelya and connected to the fan. Wherein:

- the angle of inclination of the rectangular plates to the horizontal plane is 35-40 °;

- plates to the water-cooled tubes of the grate are welded at a distance of 5-10 mm from each other;

- the ash and slag collector is formed by the lower (along the fuel) side of the grate, bent in the form of a pocket;

- the fuel hopper is installed close to the front screen of the furnace, and the upper edge of the conical bottom is tightly connected to the lower edge of the latter;

- the gate is used as a fuel dispenser.

In the future, the utility model is illustrated by a brief description of an example of its specific implementation and drawings, where Fig. 1 schematically shows a general view of the proposed device (vertical section), and Fig. 2 shows an inclined lattice (side view). A device for burning solid fuel contains a furnace 1, bounded on all sides by water tube screens 2, in communication with the respective upper and lower manifolds 3, a fuel hopper 4, is placed in front of the screen 2 of the furnace 1 above the level of the grill 5, installed at an angle α 45-55 ° to horizontally. The fuel hopper 4 has a conical (in plan) bottom 6 with an outlet 7 in which a fuel dispenser is arranged, made in the form of a slide 8 under the bottom 6 of the fuel hopper 4, an inclined feeder 9 is installed to supply fuel to the inclined grate 5. The angle of inclination of the feeder 9 is the same with an angle of inclination of the lattice 5 and is 45-55 °, which corresponds to the angle of repose for different types of fuels. When α <45 °, the movement of fuel along the feeder 9 and the grid 5 by gravity will be difficult. At α> 45 °, the speed of movement of fuel along the feeder 9 and the grill 5 will be excessively high, which will lead to its (fuel) incomplete combustion. The inclined feeder 9 and the grill 5 and ash collector 10 are made at the same time from water-cooled pipes connected by the upper end to the additional horizontal collector 11, and the lower end to the lower horizontal collector 3 of the rear screen of the furnace 1. The additional horizontal collector 11 is connected by a bypass pipe (not shown) to the lower horizontal collector 3 of the front screen 2 of the furnace 1. Water-cooled pipes of the inclined feeder 9 and the grill 5 and ash collector 10 are installed with a gap relative to each other. In this case, the gaps between the pipes of the inclined feeder 9 are tightly covered by spacers (not shown), and the transverse metal plates 12 are welded to the water-cooled pipes of the inclined grating 5 with overlap at a distance of L = 5-10 mm 12. The said plates 12 are welded to the pipes at an angle β to the horizontal plane of 35-40 °, with the formation of slit-like nozzles facing the lower (along the fuel) part of the inclined grate 5, which allows, firstly, to blow ash from the lumps of fuel, and secondly, facilitates the movement of fuel Dole lattice, excluding its slagging. The limiting values of dimensions L and inclination angles β are determined by calculation and experimentally.

At β <35 °, the nozzle cross-sectional area will be larger, and the air flow velocity (at constant pressure), respectively

less than the calculated limiting lower value. Reducing the speed of air flow will cause a decrease in the speed of movement of fuel along the inclined grate 5, below the permissible limit, which can lead to its (grating 5) slagging.

At β> 40 °, the passage area of the air nozzles decreases, which, at a constant pressure, will lead to an unnecessary increase in the speed of air flows, and, consequently, to an increase in the speed of movement of fuel and its incomplete combustion. In addition, as established experimentally, at β> 40 ° and at L <5 mm, it is difficult to weld metal plates 12 to the pipes, and the quality of the joints is deteriorated.

At L> 10 mm, the lumps of fuel can fall into the nozzles; moreover, their (nozzle) cross-sectional area will be larger than necessary to maintain the required air velocity.

In the best embodiment of the device, the fuel hopper 4 is mounted close to the front screen 2 of the furnace 1, the upper edge of its conical bottom 6 is tightly connected to the lower edge of the front screen 2 of the furnace 1, and the top is adjacent to the inclined feeder 9, so that the inclined surface facing the furnace 1 of the side of the conical bottom 6 and the working surface of the inclined feeder 9 form the base of the chamber for burning volatile substances 13, the space of which is partially combined with the space of the furnace 1, and is not closed by the side walls, as in estno prior art device.

The length of the feeder 9 and the grate 5 is calculated in a known manner and according to known dependencies based on the size of the furnace and the amount of fuel burned during the working cycle.

Ash and slag collector 10 is made at the same time with an inclined grate 5 of water-cooled pipes, which are bent from the plane of the grate 5 with the formation of a pocket. Its dimensions are calculated in a known manner, and depend on the amount of slag formed during the working cycle.

The execution of the inclined feeder 9 and the lattice 5 and the slag collector 10 at the same time from water-cooled pipes significantly, many times, increases their service life and simplifies the device.

The primary blast pipe 14 is brought under the inclined grate 5, the secondary blast pipe 15 is placed above the grate, to ensure fuel combustion.

The pipe 16 of the additional blast is led under the grate of an ash and slag trap for burning off the coke residue.

All pipelines 14, 15, 16 are connected to a fan (not shown).

The device operates as follows:

In the initial state, the gate 8 closes the outlet 7, there is no fuel supply, the fan (not shown) is turned off. Before starting work, a fan (not shown) is turned on, air begins to flow through the primary blast pipe 14 under the inclined grate 5, and through the secondary and additional blast pipes 15, 16, respectively, into the combustion chamber and under the grate of the ash and slag collector.

The gate 8 is shifted by the required amount and solid fuel flows by gravity to the inclined feeder 9 and, with a calculated speed determined by the angle of inclination of the feeder and the flowability of fuel, begins to move along the feeder 9 and ignites due to ignition. The air entering through the pipes 14, 15 provides combustion. Moreover, at the base of the chamber 13, intense emission of volatile substances and their burning out begins under the influence of temperature.

Volatile substances that do not have time to burn out burn out in the furnace 1. the inclined feeder 9 is one of the base walls of the above-mentioned burn-out chamber 13 and is made integral with the inclined grate 5, then the space of the burn-out chamber is combined for the most part with the space of the furnace 1 without additional walls restricting the volume of the burn-out chamber, and therefore, in it, as in the furnace 1, the temperature during fuel combustion does not exceed 1100-1200 ° C, which prevents (in contrast to the prototype) the formation of nitrogen oxides - one of the most harmful components of flue gases, thereby ensuring environmental safety ystva.

Further, under the action of its own weight, solid fuel, moving along the feeder 9, enters the inclined grate 5, where it continues to (fuel) combustion.

At the same time, the air entering through the slit-shaped nozzles formed by the metal plates 12, due to their inclination, blows the ash, thereby intensifying the combustion process, facilitates the movement of fuel along the grate, and prevents its slagging. The resulting slag by gravity, due to the inclination of the lattice 5, enters the ash pan 13, where the air entering

through the pipeline 16 additional blasting, provides the afterburning of coke residue.

Thus, the implementation of an inclined feeder and grate, as well as an ash and slag collector at the same time from water-cooled pipes, can significantly simplify the design of the device, increase its durability and reliability.

Placing the fuel hopper above the feeder, making the feeder and grate inclined at an angle of 45-55 °, and tilting the plates at an angle of 35-40 ° to the horizontal ensure the movement of fuel by gravity without slagging the grate, which also simplifies the device.

The use of the working surface of the inclined feeder and its conjugate facing the furnace of the wall of the conical bottom of the fuel hopper as the base of the combustion chamber and the partial combination of its space with the space of the furnace limited by screens makes it possible to simplify and cheapen the device and ensure the burning of volatile substances without the emission of nitrogen oxides, thereby increasing the environmental safety of the device.

Claims (6)

1. A device for burning solid fuel, including a furnace, laterally bounded by water-tube heat exchanger screens connected to the corresponding upper and lower collectors, a fuel hopper with a conical (in plan) bottom and an outlet made therein, a fuel dispenser, an inclined feeder, paired with one side with the fuel hopper, an inclined grate with transverse air gaps formed by metal plates installed with overlap, the chamber for burning volatile substances in communication with the furnace, primary air duct connected to the fan and ash trap located in the lower part of the furnace, characterized in that the rear wall and the upper part of the front wall of the furnace are also formed by water tube heat exchangers connected from the bottom and top to the respective horizontal headers, the fuel hopper is located above the feeder in front of the front the screen so that its bottom is located under the lower edge of the latter, the beveled wall of the bottom faces the furnace space and is tightly connected to the front screen with the development of the lower part of the front wall of the furnace, while the beveled bottom wall of the hopper and the working surface of the inclined feeder are the base of the chamber for burning volatile substances, the inclined feeder, grate, and ash collector are made up of water-cooled pipes installed with a gap relative to each other and connected, respectively, to additional horizontal collector and lower rear screen collector, while the gaps between the water-cooled pipes of the inclined feeder and the ash side wall the gas trap is sealed with gas spacers, metal plates to the water-cooled tubes of the grate are welded at an angle to the horizontal plane with the formation of slit-like nozzles facing the lower (along the fuel path) part of the grate, the angle of inclination of the feeder and grate to the horizontal plane is 45-55 °, an additional horizontal collector connected by the bypass pipe to the lower horizontal collector of the front screen, and the furnace is equipped with pipelines of the secondary and additional blast, located, respectively, above inclined grate in the combustion zone and under the grate of the ash and slag collector and connected to the fan. 2. The device according to claim 1, characterized in that the angle of inclination of the rectangular plates to the horizontal plane is 35-40 °. 3. The device according to claim 1, characterized in that the plates to the water-cooled tubes of the lattice are welded at a distance of 5-10 mm from each other. 4. The device according to claim 1, characterized in that the ash and slag collector is formed by the lower (along the fuel) part of the grate, bent in the form of a pocket. 5. The device according to claim 1, characterized in that the fuel hopper is installed close to the front screen of the furnace, and the upper edge of the conical bottom is tightly connected to the lower edge of the latter. 6. The device according to claim 1, characterized in that the gate is used as a fuel dispenser.