RU2319065C1 - Method of burning and dry distillation of solid fuel - Google Patents

Abstract

FIELD: heat power engineering.

SUBSTANCE: method comprises setting a sample of fuel to the chamber, heating it up to a temperature of extracting of violet fractions, separating vapor phase from the solid phase, and burning the solid phase in the furnace.

EFFECT: enhanced combustion efficiency.

4 cl, 3 dwg

Description

The invention relates to a power system and can be used to burn fuel and produce energy (technological) gas.

A known method of burning solid fuel by feeding it with a screw through a retort into the burning layer of the combustion chamber, followed by afterburning on slowly rotating drums and removing slag [1].

The disadvantages of this method are:

- incomplete combustion of fuel, due to the fact that large pieces of fuel that have already partially burnt onto the drum and do not have time to completely burn out before falling into the slag collector. If you try to rotate the drum more slowly, these pieces will be filled with slag from the small-sized fuel that has passed through the retort and has already burned. Moreover, since the pieces of fuel falling on the drum are scattered and are removed from the high-temperature combustion zone during its rotation, the burning intensity decreases, which does not allow them to burn completely. If to intensify the combustion of pieces on the drum, place the latter closer to the high-temperature zone, then the slag removed later will have a high temperature, which will lead to an increase in heat loss and, ultimately, to a decrease in the efficiency of the furnace;

- a device that implements this method requires significant energy costs for driving screws and drums, which also reduces the overall efficiency of the installation.

There is a method of burning solid fuels, including the supply of fuel to the combustion zone, its ignition and combustion with the crushing of large pieces, the removal of small fractions of slag through the slit grate, which is periodically expanded to remove larger fractions from the combustion zone [2].

The disadvantages of this method are:

- incomplete combustion of fuel, due to the fact that its pieces, commensurate with the size of the slit of the grate, fall together with the slag into the dump. If the gap is made very small, the resulting slag will be poorly removed from the combustion zone and prevent the latter;

- crushing pieces of fuel involves additional energy costs, which reduces the efficiency of the installation;

- instability of the combustion process over time (especially when small amounts of fuel are burned) due to a partial or complete cessation of combustion when the remaining portion of the previous portion is filled with fresh fuel.

The prototype is a method of burning and dry distillation of solid fuel, which includes placing the fuel in a chamber, heating it to a volatile exit temperature, separating the vapor and solid phases and burning the latter in the furnace [3].

The disadvantages of the prototype are:

- incomplete combustion of fuel associated with mechanical entrainment of coal dust, which, ultimately, reduces the efficiency of the furnace;

- the complexity of the design of the installation that implements the method;

- a narrow range of the degree of thermal decomposition of solid fuels.

The objective of the invention is to remedy these disadvantages, namely increasing the completeness of combustion of fuel, simplifying the design of the furnace and increasing its efficiency, as well as increasing the range of thermal decomposition of fuel and obtaining high-quality energy gas. The problem is solved in that in the method of burning and dry distillation of solid fuel, which includes placing fuel in a chamber, heating it to a volatile exit temperature, separating the vapor and solid phases and burning the latter in the furnace, it is heated from the inside above the temperature before placing the fuel in the chamber, at which the bulk of the volatiles exit, and the placement of fuel in the chamber is accompanied by its impact on the chamber walls.

Fuel is burned in portions. Before heating the chamber from the inside, the separation of vapor and solid phases is stopped. The heating of the chamber from the inside is combined with the beginning of the combustion of the solid phase of the fuel. The vapor and solid phases are separated in the process of heating, which is carried out in the furnace.

The prior art does not reveal solutions that have signs that match the distinctive features of the claimed invention and have the same effect as they, on the technical result, consisting in increasing the completeness of combustion of fuel, simplifying the design of the furnace and increasing its efficiency, as well as increasing the range thermal decomposition of fuel and obtaining high-quality energy gas.

The invention is reflected in the operations:

- before placing the fuel in the chamber, it is heated from the inside above the temperature at which the bulk of the volatile matter is released;

- the placement of fuel in the chamber is accompanied by its impact on the walls of the chamber;

- fuel is burned in portions;

- before heating the chamber from the inside, the separation of vapor and solid phases is stopped;

- heating the chamber from the inside is combined with the beginning of the combustion of the solid phase of the fuel;

- vapor and solid phases are separated in the process of heating, which is carried out in the furnace.

These operations allow you to achieve the following advantages compared with the prototype.

Heating the chamber from the inside above the temperature at which the bulk of the volatiles exit, before placing the fuel in it reduces the mechanical entrainment of coal dust, which, touching the heated walls of the chamber, passes into a plastic state and adheres to the walls. Moreover, heating is carried out, for example, by flue gases, directing them directly to the inner surface of the chamber. As a result of this, the completeness of fuel combustion and efficiency increase.

The impact of fuel on the walls of the chamber when it is placed in the chamber also reduces the mechanical entrainment of coal dust, which flies from the solid phase (pieces) of fuel upon impact and adheres to the heated walls. Pieces of fuel are cleaned up and, getting into the furnace, no longer create clouds of dust that are carried away by the flue gases. The impact is produced, for example, by throwing coal from a certain height.

Combustion of fuel in batches allows you to quickly manage the processes of thermal decomposition of fuel and combustion, and also contributes to better cleaning of pieces of fuel from coal dust. All this increases the efficiency and increases the completeness of fuel combustion.

The cessation of the separation of vapor and solid phases before heating the chamber from the inside makes it possible to exclude the ingress of air or combustion products into the gas obtained during thermal decomposition of the fuel, which increases its quality.

The combination of heating the chamber from the inside with the beginning of the combustion of the solid phase of the fuel does not allow it to cool down significantly after completion of the process of thermal decomposition of fuel in it, which reduces the heat loss from heating its walls from the inside above the temperature at which the bulk of the volatiles exit. This increases the efficiency of the furnace.

The separation of vapor and solid phases during the heating process, which is carried out in the furnace, allows to simplify the design of the device that implements the method, and to provide an increase in the range of thermal decomposition of fuel.

The invention is illustrated by drawings.

Figure 1 shows a device for burning and dry distillation of solid fuel.

Figure 2 shows a device for burning and dry distillation of solid fuel in the process of thermal decomposition of a portion of fuel.

Figure 3 shows a device for burning and dry distillation of solid fuel after the process of thermal decomposition of a portion of fuel.

A device for burning and dry distillation of solid fuel contains a boiler 1 with water 2 and a furnace 3, in which a chamber 4 with a reclining bottom 5 and a cover 6 is placed. The chamber is connected to a box 7 for loading fuel 8 and through a valve 9 to a heat exchanger 10 having thermal contact with water.

The device operates as follows.

Before loading the next portion of the fuel 8, the cover 6 and the bottom 5 of the chamber 4, as well as the valve 9 are closed (figure 1). Open the lid 6 and fill the entire internal volume of the chamber 4 with fuel 8 (for example, coal). In this case, the placement of fuel in the chamber is accompanied by its impact on the walls of the chamber, which occurs as a result of a collision with the walls of the fuel moving along the inclined box 7.

Then close the lid of the chamber, open the valve 9, heat the chamber to the outlet temperature of the volatile and at the same time separate the vapor and solid phases by suctioning gas released during thermal decomposition through the heat exchanger 10 (Fig. 2). Passing through the heat exchanger, the gas gives its heat to water, as a result of which it is cooled, and the efficiency of the boiler furnace increases. The resulting gas can be used for domestic purposes.

After separation of the bulk of the volatiles, the separation of the vapor and solid phases is stopped (by closing the valve 9 and opening the bottom 5 of the chamber) and the solid phase of the fuel is burned directly in the furnace 3 (Fig. 3). Note that depending on the heating temperature of the chamber, it is possible to obtain coke or semi-coke, i.e. placing the chamber in the appropriate temperature zone of the furnace (bertination - t = 180 ÷ 350 ° C, semi-coking - t = 550 ° C, coking = 900 ÷ 1100 ° C), the required quality of the solid phase and gas is obtained. At the same time, the chamber is heated from the inside above the temperature at which the bulk of the volatile matter is released. Heating is produced, for example, by incandescent combustion products, directing them directly to the inner surface of the chamber (Fig. 3). Upon reaching the desired temperature, close the bottom 5 of the chamber, open the lid 6 and fill the internal volume of the chamber with another portion of fuel. Then repeat the process. Note that the resulting gas can also be used for combustion in the furnace.

The implementation of the invention will significantly increase the efficiency of combustion devices by reducing the mechanical entrainment of fuel, reduce the pollution of the atmosphere of cities and towns, and also make it possible to obtain gas for domestic needs.

Information sources

1. A.S. USSR No. 1281814, F23В 1/32, 1987 - analogue.

2. A.S. USSR No. 1165849, F23H 9/00, 1980 - analogue.

3. A.S. USSR No. 87639, class C10J 3/46, 1950 - prototype.

Claims (5)

1. A method of burning and dry distillation of solid fuel, comprising placing fuel in a chamber, heating it to a volatile exit temperature, separating the vapor and solid phases and burning the latter in the furnace, characterized in that it is heated from the inside above the temperature before placing the fuel in the chamber, which the bulk of the volatiles exit, and the placement of fuel in the chamber is accompanied by its impact on the chamber walls. 2. The method according to claim 1, characterized in that the fuel is burned in portions. 3. The method according to claim 1, characterized in that before heating the chamber from the inside, the separation of vapor and solid phases is stopped. 4. The method according to claim 1 or 2, characterized in that the heating of the chamber from the inside is combined with the beginning of the combustion of the solid phase of the fuel. 5. The method according to claim 1, characterized in that the vapor and solid phases are separated in the process of heating, which is carried out in the furnace.

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