RU2702069C1 - Vertical fire grate of boiler furnace - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: invention relates to the field of power engineering. Boiler furnace vertical fire grate forms vertical cavity over fuel-free furnace height, at that vertical fire grate comprises hollow vertically oriented grates, which cavities are communicated hydraulically at the top and bottom of the furnace with water jacket of boiler. Grates of fire grate are made parallel and rectilinear. Gap between grates of fire grate is 12–20 mm. Vertical cavities are formed in amount of at least two. Fire grate is made flat.

EFFECT: invention provides higher efficiency of heat extraction from combustion of solid fuel loaded into boiler.

5 cl, 3 dwg

Description

The invention relates to the field of energy, in particular to heat engineering, and can be used in long-burning boilers of small and medium capacity, operating on solid fuel.

Known grate, consisting of steel pipes of rectangular cross-section, laid in parallel at a distance of 20 mm from each other, welded from one end to the inlet manifold, and from the other - into the outlet manifold at an angle that allows the coolant to circulate inside these pipes of rectangular cross-section, through which the pipes cooled inside. Sections of a steel bar are welded between steel pipes at a distance of 15-20 mm from each other, which are compensators, which together with the plane of rectangular pipes form the working surface of the device (see RU No. 2382944, F23H 3/02, F24H 1/12).

The disadvantages of this design include the irrational cross-section of the grate pipes, which leads to jamming of the grate and the formation of slag crust and sintered slag on the grate, while the welded sections of the steel bar - expansion joints - worsen the passage of air into the fuel combustion zone, thereby complicating the natural ash passage into the ash pan of the boiler.

Also known is the vertical grate of the furnace of the boiler, forming a vertical cavity along the height of the furnace of the boiler, free of fuel (see RU No. 2092746, F24H 1/36, 1991).

The disadvantage of this solution is the insufficient heat removal from the combustion of solid fuel, since the vertical grate is formed in the middle of the boiler coaxially with its vertical axis and is not hollow, therefore, the process of fuel combustion occurs in the lower part of the furnace (above the horizontal grate) and around the vertical channel, while the heat from the combustion of fuel does not go to the walls of the furnace (and heating the water in the boiler’s water jacket), since the latter are covered by a layer of fuel.

An object of the invention is to increase the efficiency of heat removal from the combustion of solid fuel loaded into the boiler.

The technical result obtained by solving the problem of the invention is to ensure the transfer of heat from fuel combustion in vertical cavities to the walls of the furnace and the transfer of heated water to the water jacket from the vertical and horizontal grate.

The technical problem is solved due to the fact that the vertical grate of the furnace of the boiler, forming a vertical cavity along the height of the furnace free of fuel, differs in that the vertical grate of the furnace contains hollow, vertically oriented grates, the cavities of which are hydraulically at the top and bottom of the furnace with the water jacket of the boiler . In addition, the grate of the grate is made parallel and rectilinear. In addition, the gap between the grates of the grate is 12-20 mm. In addition, the vertical cavities are formed in an amount of at least two. In addition, the grate is made flat.

A comparative analysis of the features of the claimed solution with the features of the prototype and analogues indicates the conformity of the claimed solution to the criterion of "novelty."

Moreover, the set of features of the distinctive part of the claims provides an increase in the efficiency of heat removal from burning solid fuel loaded into the boiler.

Moreover, the hallmarks of the distinctive part of the claims provide a solution to the following complex of functional tasks.

Signs indicating that the vertical grate of the long-burning boiler "contains hollow, vertically oriented grates" provides the possibility of "isolation" of the volume of the furnace adjacent to its wall by the grid and, thus, direct transfer of heat to the furnace walls (forming the second wall of the boiler water jacket) from burning fuel in contact with vertical cavities.

Signs indicating that the grate cavities are "hydraulically, at the top and bottom of the furnace connected to the boiler water jacket" ensure the transfer of heated water to the water jacket from the vertical grate and protect the grate from destruction when burning coal with high calorific value.

Signs indicating that "the grid-irons of the grate are parallel and rectilinear" simplify the process of manufacturing vertical grates and make it possible to ensure a high density of the heat-removing surface. Signs indicating that "half of the surface area of each grate, facing the fuel, is larger than the surface area of their rear half" contribute to increasing the efficiency of heat removal by grate.

Signs indicating that the “gap between the grid-irons of the grate is 12–20 mm” sets the design parameters of the grate grids providing the possibility of “automatic” downward displacement (due to gravity) of the loading of solid fuel as it burns out in contact with the grate, excluding it filling with pieces of fuel.

Signs indicating that “vertical cavities are formed in an amount of at least two” set the conditions under which it is possible to form a fuel volume that is optimal in width from the perspective of its preliminary preparation for burning (in which the volume dries and warms up and is sufficiently gasified for subsequent efficient combustion .

Signs indicating that "the grate is made flat" can minimize the number of grate grates with equal areas of the gratings in the plan.

In FIG. 1 schematically shows a fragment of a cross section of a boiler (bottom view); in FIG. 2 schematically shows a vertical section of the boiler (option - in the presence of upper collectors); in FIG. Figure 3 schematically shows a vertical section of the boiler (option - in the absence of upper collectors).

The drawings show a vertical grate of the furnace 1 of the boiler, containing vertically oriented grates 2, a water jacket 3 of the boiler, upper 4 and lower 5 headers, center 6 of the furnace 1, waterproof housing 7, exhaust pipe 8, gas outlet 9, vertical cavity 10, upper loading hatch 11. In addition, arrows show the movement of coolant (water) flows during its heating.

The grates 2 of the vertical grate are hollow, parallel and rectilinear. The gap between the grates 2 of the grate is 12-20 mm. The grate is flat as shown in FIG. 1. It is possible to make the lattice convex, with the vertical axes of the grid-irons being placed on an arc of a circle or on a broken line, convex to the center 6 of the furnace 1 or on a circle parallel to the furnace wall.

The water jacket 3 of the boiler is formed as a tight gap between the wall of the waterproof housing 7 and the wall of the furnace 1. The waterproof housing 1 (preferably provided with a heat-insulating layer is not shown in the drawings) is equipped with an exhaust pipe 8, which is connected through one of the vertical cavities 10 from one of the vertical cavities 10 , the perimeter of which is formed by the wall section of the furnace 1 and the grate.

For example, a boiler is shown in the cavity of which there are two vertical grates, placed symmetrically relative to the center 6 of the furnace 1.

To communicate the cavities of vertically oriented grates 2 with a water jacket 3 of the boiler, their lower ends are hermetically connected to the lower manifolds 5, the cavities of which, in turn, are hermetically connected to the lower section of the water jacket 3, and the upper ends are hermetically connected to the upper manifolds 4. When the presence of several vertical grates, the task of communicating with a water jacket 3 is solved in a similar way - by means of the upper and lower collectors.

It is possible that the lower ends of the rectilinear grid-irons 2 are also hermetically connected with the lower collectors, and their upper ends are not hermetically connected with the upper collectors 4, but directly with the upper part of the boiler water jacket 3 (in this case, the upper collectors 4 are absent).

Vertical cavities 10 (if there are several) or one (if it is circular or sector) are located on the periphery of the furnace, aerodynamically communicated from below with a blowing cavity (not shown in the drawing), and above with a gas outlet 9 connected to the exhaust pipe 8.

The work of the proposed vertical grate is as follows.

Water is poured into the cavity of the water jacket 3 through the inlet pipe (not shown in the drawing) until it is completely filled, including the grate cavities, after which it is connected to the heating system by means of a discharge pipe (not shown in the drawing). Then, a layer of wood pulp is laid on the horizontal grate of the furnace (not shown) for subsequent ignition of coal, after which through the upper loading hatch 11 the remaining volume of furnace 1 (except for the volumes of vertical cavities 10) is filled with solid fuel (coal) and ignited, for example, household gas burner (through the blower) a layer of wood pulp. After the ignition of coal in contact with wood pulp, the combustion process is in the "automatic mode". In this case, the combustion products together with the air flow coming through the blower and then through the cracks between the grates of the horizontal grate, interact with the lower layer of coal, and also fall into the vertical cavities 10 where they interact (through the gaps between the parallel rectilinear grates 2 of the vertical grate) with a vertical layer of coal adjacent to the grate.

With appropriate control of the volumes of air supplied, direct heat transfer (from burning fuel on the horizontal grate) to the vertical surface of coal in contact with the vertical grate leads to pyrolysis of this part of the fuel. In addition, there is an intensive direct transfer to the walls of the furnace of heat from burning fuel on a horizontal grate.

Further, along the vertical cavities 10, the combustion products flow upward, so that the hottest volume of gases accumulates at the top in the thermal dome (formed due to the displacement of the exhaust pipe 9 downward from the upper end of the boiler), while water is “cooling this volume” in the boiler’s water jacket and forcing it out with new portions of hot gas, gradually the lower boundary of the thermal dome falls to the exhaust pipe 9 through which the cooled gases fall into the exhaust pipe 8 and are removed into the atmosphere.

Under the action of heat from burning fuel, the water in the cavity of the water jacket heats up and is supplied for circulation through a heating system (not shown) and, thereby, heats the premises.

As the fuel burns in the furnace 1, ash and slag through a horizontal grate go by gravity to the blower from the bottom of the furnace 1, and a layer of coal is pressed in their place (under their own weight) adjacent to the burnt out one. In this case, air freely enters the combustion zone from the bottom of the fuel column and onto its vertical surfaces in contact with the vertical cavities 10. As the fuel burns, slag and ash are removed from the blower, and the next portion of coal is poured into the furnace, and the process continues.

The use of the invention will improve the operational quality of the heating boiler and provide a guaranteed continuous combustion process during long-term operation of the boiler without constant monitoring and maintenance of the combustion process.

Claims (5)

1. The vertical grate of the furnace of the boiler, forming a vertical cavity along the height of the furnace, free of fuel, characterized in that the vertical grate of the furnace contains hollow vertically oriented grates, the cavities of which are hydraulically at the top and bottom of the furnace connected to the water jacket of the boiler. 2. The grate according to claim 1, characterized in that the grate of the grate is made parallel and rectilinear. 3. The grate according to claim 1, characterized in that the gap between the grates of the grate is 12-20 mm. 4. The grate according to claim 1, characterized in that the vertical cavities are formed in an amount of at least two. 5. The grate according to claim 1, characterized in that the grate is made flat.

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