CN100570215C - Storehouse type coal-burning boiler few-oil ignition combustion system - Google Patents

Abstract

The invention discloses a storage-type coal-fired boiler oil-less ignition combustion system. The output port of the main coal mill is connected with a fine powder separator. The fine powder separator communicates with the primary air main pipe. The outer primary air pipe is connected; the ultrafine powder separator is arranged side by side with the fine powder separator to communicate with the primary air secondary pipe, and the primary air secondary pipe is connected to the inner primary air pipe of the burner; the outlet section of the inner primary air pipe is internally fixed There is an oil gun, a pipeline is connected between the primary air main pipe and the primary air secondary pipe, a pipeline valve is installed on the pipeline, and a secondary air pipe valve is installed on the primary air secondary pipe in front of the pipeline valve. The invention has a simple structure, realizes separate combustion of coarse and fine coal powder, greatly improves the stability of boiler ignition and low-load operation, saves fuel, reduces power generation costs, and also has the advantages of anti-coking and wide adaptability of coal types.

Description

Oil-less ignition and combustion system for storage coal-fired boilers

technical field

The invention belongs to the technical field of ignition and combustion devices for thermal power generation, in particular to a storage-type coal-fired boiler low-oil ignition and combustion system used for igniting boilers in thermal power plants.

Background technique

As a large consumer of fuel oil, thermal power plants consume a large amount of fuel oil for boiler ignition and stable combustion every year. According to the data from the Development and Reform Commission, the annual fuel consumption of my country's generator sets is as high as 7.6 million tons, equivalent to 41.8 billion yuan. my country is an oil-poor country. In 2004, the oil consumption was 317 million tons, the domestic production was 176 million tons, the net import was 151 million tons, and the foreign dependence reached 47.3%. Therefore, reducing the fuel consumption of power generation is of great significance for reducing the cost of power generation, improving the economic benefits of power generation enterprises and my country's energy security strategy.

In 2005, the country launched the "Medium and Long-term Special Plan for Energy Conservation", and put forward the goal of saving and replacing 38 million tons of oil during the "Eleventh Five-Year Plan" period. In order to reduce the cost of power generation and achieve the goal of saving fuel, it is the most urgent demand for power plants to develop and install new ignition combustion technology for fuel-saving boilers. At present, the ignition and combustion devices of most coal-fired power plants in my country mainly include a coal mill, a primary air duct, a burner and a furnace. Connected with the burner, the burner is located at the lower part of the furnace, the burner is composed of an outer primary air pipe and an oil gun, wherein the oil gun is located on the main axis of the outer primary air pipe, and the nozzle of the oil gun is close to the outer primary air The outlet of the pipe; and on the inner wall of the outlet section of the outer primary air pipe near the nozzle of the oil gun, a ring of bosses is set as a pulverized coal concentrator. At the initial stage of ignition, the oil gun sprays a large amount of fuel oil into the furnace, and after the oil is heated for a period of time, the pulverized coal is sprayed out through the primary air pipe and the outlet of the primary air pipe outside the burner, and the pulverized coal is burned outside the outlet. After the combustion is stable, turn off the oil passage of the oil gun.

However, the quality of coal fired by power stations in my country generally deviates and fluctuates greatly. If the pulverized coal is too coarse, it will be difficult to achieve full combustion at the initial stage of ignition, and a large amount of fuel oil will be consumed, which will greatly increase the fuel consumption; Tube explosion on the heating surface affects the safe operation of the power plant.

Disadvantages of the existing storage-type coal-fired boiler with low oil ignition and combustion system: in the initial stage of ignition and combustion of the boiler in the power plant and during low-load operation, the combustion is unstable and the oil consumption is large; Easy to coke.

Contents of the invention

Aiming at the problems existing in the prior art, the object of the present invention is to provide a low-oil ignition and combustion system for storage-type coal-fired boilers, which can not only save fuel oil at the initial stage of ignition and combustion and during low-load operation, but also prevent coking when the boiler is running stably , A low-oil ignition combustion device for a once-through boiler that reduces the cost of thermal power generation.

In order to achieve the above object, the technical solution of the present invention is as follows: a storage type coal-fired boiler oil-less ignition combustion system, including a coal mill, a primary air main pipe, a burner and a furnace, wherein the burner is located at the lower part of the furnace, and its The key is: the burner is composed of an outer primary air duct, an inner primary air duct and an oil gun, wherein the oil gun is located on the main axis of the inner primary air duct, and the nozzle of the oil gun is close to the outlet of the inner primary air duct; The air duct is located on the main axis of the outer primary air duct, and the outlet of the inner primary air duct is close to the outlet of the outer primary air duct;

The output port of the coal mill is connected with a fine powder separator, and the output port of the fine powder separator is connected with a fine powder storage bin through a pipeline, and the fine powder storage bin communicates with the primary air main pipe, and the primary air main pipe The outlet communicates with the inlet of the outer primary air duct; an ultrafine powder separator is arranged side by side with the fine powder separator, and the output port of the ultrafine powder separator is connected to an ultrafine powder storage bin through a pipeline. The powder storage bin communicates with the secondary air pipe, and the outlet of the secondary air pipe communicates with the inlet of the inner primary air pipe; the oil gun passes through the inner primary air pipe and the outer primary air pipe, and the tail of the oil gun is connected with an oil pipe ;

A pipe is connected between the primary air main pipe and the primary air auxiliary pipe, and a pipe valve is installed on the pipe, and an auxiliary air pipe valve is installed on the primary air auxiliary pipe in front of the pipe valve.

A branch pipe is installed on the primary air secondary pipe in front of the secondary air pipe valve, the outlet of the branch pipe extends into the furnace, and is located above the outlet of the primary air main pipe, and a branch pipe valve is installed on the branch pipe.

The fine powder separator and the ultrafine powder separator separate coal powders of different fineness, and store them in the fine powder storage bin and the ultrafine powder storage bin respectively, and send them to the furnace and boiler through the primary air main pipe and the primary air secondary pipe When ignition starts, low-load operation, and coal quality deviation, ultra-fine coal powder enters the furnace for combustion through the primary air secondary pipe and the primary air pipe in the burner, which is conducive to ignition and stable combustion, effectively reducing the oil used for ignition and stable combustion. Fuel is saved; after the boiler combustion is stable, the fine coal powder enters the primary air duct and the outer primary air duct of the burner through the primary air main pipe to burn at the same time, and the ultra-fine coal powder is sprayed from the upper part of the primary air nozzle of the furnace through the primary air secondary pipe and branch pipe , thereby delaying the ignition of pulverized coal, preventing coking of the burner and nearby heating surfaces, ensuring the safe and efficient operation of the power plant, and reducing NO _X emissions.

The furnace is also connected with a secondary air pipe, and the outlet of the secondary air pipe is located above the outlet of the primary air main pipe.

Fans are installed at the inlets of the primary air main pipe, primary air secondary pipe and secondary air pipe to communicate with the atmosphere. The fan sends oxygen into the furnace to promote the full combustion of pulverized coal in the furnace.

A ring of bosses is arranged on the inner wall near the outlet of the inner primary air pipe near the nozzle of the oil gun.

As a pulverized coal concentrator, the boss separates the pulverized coal in the inner primary air duct from thick to thin, so that the concentrated pulverized coal burns in the central area of the outlet of the outer primary air duct, which is easy for the pulverized coal to ignite and burn stably.

Both the fine powder separator and the ultrafine powder separator are cyclone separators, and the air outlet pipe of the fine powder separator communicates with the ultrafine powder separator, and the air outlet pipe of the ultrafine powder separator communicates with the furnace, A fan is installed on the air outlet pipe of the superfine powder separator.

The fine powder separator separates the fine coal powder, if the coal powder is anthracite, the R ₉₀ of the fine coal powder is 6-10%; if the coal powder is lean coal, the R ₉₀ of the fine coal powder is 12-14%; If the pulverized coal is bituminous coal, the R ₉₀ of the fine coal powder is 15-35%; if the pulverized coal is lignite, the R ₉₀ of the fine coal powder is 40-60%; The fineness of fine coal powder is 1/2-1/3 of that of fine coal powder.

Beneficial effects: the structure of the present invention is simple, can realize the separate combustion of coarse and fine coal powder, greatly improves the stability of boiler ignition and low-load operation, saves fuel at the initial stage of ignition and combustion and low-load operation, and prevents coking when the boiler is in stable operation , reduce the cost of thermal power generation, and also reduce the emission of boiler NO _X. Compared with traditional technology, it is more environmentally friendly and has the characteristics of wide adaptability to coal types. It can realize fuel-saving ignition, stable combustion, and optimized combustion according to coal types and operating conditions. , can self-adaptive less oil ignition and stable combustion.

Description of drawings

Fig. 1 is a schematic diagram of the system of the present invention;

Figure 2 is a schematic structural view of the burner.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

As shown in Figures 1 and 2, a storage-type coal-fired boiler with less oil ignition combustion system consists of a coal mill 1, a primary air main pipe 2, a primary air secondary pipe 2', a burner 11, a furnace 4, and a fine powder separator 5. Composed of ultrafine powder separator 5', fine powder storage bin 6, ultrafine powder storage bin 6' and pipeline 7, wherein the burner 11 is located at the lower part of the furnace 4, and the burner 11 is connected by an outer primary air duct 12 , the inner primary air duct 12' and the oil gun 3, wherein the oil gun 3 is located on the main axis inside the inner primary air duct 12', and the nozzle of the oil gun 3 is close to the outlet of the inner primary air duct 12'; the inner primary air duct 12' is located on the main axis of the outer primary air duct 12, and the outlet of the inner primary air duct 12' is close to the outlet of the outer primary air duct 12;

The output port of the coal mill 1 is connected with a fine powder separator 5, and the output port of the fine powder separator 5 is connected with a fine powder storage bin 6 through a pipeline, and the fine powder storage bin 6 communicates with the primary air main pipe 2 , the outlet of the primary air main pipe 2 communicates with the inlet of the outer primary air pipe 12; an ultrafine powder separator 5' is arranged side by side with the fine powder separator 5, and the output port of the ultrafine powder separator 5' The superfine powder storage bin 6' is connected through the pipeline, and the ultrafine powder storage bin 6' communicates with the secondary air pipe 2', and the outlet of the secondary air pipe 2' communicates with the inlet of the inner primary air pipe 12' ; The oil gun 3 passes through the inner primary air duct 12' and the outer primary air duct 12, and the tail of the oil gun 3 is connected with an oil pipe 13;

A pipe 7 is connected between the primary air main pipe 2 and the primary air auxiliary pipe 2', and a pipe valve a is installed on the pipe 7, and an auxiliary air pipe valve b is installed on the primary air auxiliary pipe 2' in front of the pipe valve a. .

A branch pipe 8 is installed on the primary air secondary pipe 2' in front of the secondary air pipe valve b. The outlet of the branch pipe 8 extends into the furnace 4 and is located above the outlet of the primary air main pipe 2. A branch valve c is installed.

The fine powder separator 5 and the ultrafine powder separator 5' separate coal powders of different fineness respectively, and store them in the fine powder storage bin 6 and the ultrafine powder storage bin 6' respectively, and pass through the primary air main pipe 2 and the primary air The auxiliary pipe 2' is sent to the furnace 4. When the boiler is ignited, operated at low load, and the coal quality is deviated, the ultra-fine coal powder enters the furnace through the primary air auxiliary pipe 2' and the primary air pipe 12' in the burner, which helps Ignition and stable combustion can effectively reduce the fuel consumption for ignition and stable combustion, and save fuel; after the boiler burns stably, the fine coal powder enters the primary air duct 12' and the outer primary air duct 12 of the burner through the primary air main pipe 2 to burn at the same time. Fine coal powder is sprayed from the upper part of the primary air nozzle of the furnace 4 through the primary air pipe 2' and the branch pipe 8, thereby delaying the ignition of the coal powder, preventing the burner and nearby heating surfaces from coking, ensuring the safe and efficient operation of the power plant, and reducing _NOx at the same time emissions.

The furnace 4 is also connected with a secondary air pipe 9 , and the outlet of the secondary air pipe 9 is located above the outlet of the primary air main pipe 2 .

The inlet of described primary air main pipe 2, primary air secondary pipe 2 ' and secondary air pipe 9 is equipped with blower fan and communicates with atmosphere. The fan sends oxygen into the furnace 4 to promote the full combustion of pulverized coal in the furnace 4 .

A circle of bosses 10 are arranged on the inner wall near the outlet of the inner primary air pipe 12 ' of the nozzle of the oil gun 3 .

The boss 10, as a pulverized coal concentrator, separates the pulverized coal in the inner primary air duct 12' from thick and thin, so that the thick pulverized coal is concentrated in the central area of the outlet of the outer primary air duct 12 for combustion, which is easy for the pulverized coal to ignite and burn stably.

Described fine powder separator 5 and ultrafine powder separator 5 ' are all cyclone separators, and the air outlet pipe of fine powder separator 5 communicates with ultrafine powder separator 5 ', and the outlet of ultrafine powder separator 5 ' The air duct communicates with the furnace 4, and a fan 14 is installed on the air outlet duct of the superfine powder separator 5'.

The fine powder separator 5 separates the fine coal powder, if the coal powder is anthracite, the R ₉₀ of the fine coal powder is 6-10%; if the coal powder is lean coal, the R ₉₀ of the fine coal powder is 12-14%; If the pulverized coal is bituminous coal, the R ₉₀ of the fine coal powder is 15-35%; if the pulverized coal is lignite, the R ₉₀ of the fine coal powder is 40-60%; the ultra-fine powder separator 5' separates the ultra-fine coal The fineness of superfine coal powder is 1/2-1/3 of that of fine coal powder.

Its working principle is:

The pulverized coal produced by the main pulverizer 1 is sent to the fine powder separator 5, and the fine powder separator 5 and the superfine powder separator 5' separate coal powders of different fineness and store them in the fine powder storage bin respectively 6 and ultra-fine powder storage bin 6', it is sent to the furnace 4 through the primary air main pipe 2, primary air auxiliary pipe 2' and burner. The pipe 12' is sent into the furnace, and the fine coal powder enters through the primary air main pipe 2 and the primary air pipe 12 outside the burner. After the combustion is stable, the ultra-fine pulverized coal is sprayed into the furnace 4 through the primary air secondary pipe 2 ', the branch pipe valve c, and the branch pipe 8 outlet.

When the boiler is ignited, operated at low load, and the coal quality deviates, close pipe valve a, branch pipe valve c, open auxiliary air pipe valve b, and ultra-fine coal powder enters through primary air auxiliary pipe 2' and primary air pipe 12' in the burner Combustion in the furnace is helpful for ignition and stable combustion, effectively reducing the oil consumption for ignition and stable combustion;

After the boiler combustion is stable, open the pipe valve a and the branch pipe valve c, close the auxiliary air pipe valve b, and the superfine coal powder is injected from the branch pipe 8, and the fine coal powder enters the inner primary air pipe 12' of the burner through the primary air pipe 2 at the same time , Outer primary air duct 12, which delays the ignition of pulverized coal and prevents coking of the burner and nearby heating surfaces; it has the characteristics of fuel saving, coking prevention, safety, and wide adaptability to coal types, and can be realized according to coal types and operating conditions Fuel-saving ignition, stable combustion, optimized combustion, etc., can realize adaptive low-fuel ignition and stable combustion.

Claims (5)

1. A storage type coal-fired boiler oil-less ignition combustion system, comprising a coal mill (1), a primary air main pipe (2), a burner (11) and a furnace (4), wherein the burner (11) is located in the The lower part of the furnace (4), characterized in that: the burner (11) is composed of an outer primary air duct (12), an inner primary air duct (12') and an oil gun (3), wherein the oil gun (3) is located at On the main axis in the inner primary air duct (12'), and the nozzle of the oil gun (3) is close to the outlet of the inner primary air duct (12'); the inner primary air duct (12') is located in the outer primary air duct (12) On the inner main axis, the outlet of the inner primary air duct (12') is close to the outlet of the outer primary air duct (12); The output port of the coal mill (1) is connected with a fine powder separator (5), and the output port of the fine powder separator (5) is connected with a fine powder storage bin (6) through a pipeline, and the fine powder storage bin ( 6) communicate with the primary air main pipe (2), the outlet of the primary air main pipe (2) communicates with the inlet of the outer primary air pipe (12); Fine powder separator (5'), the output port of the superfine powder separator (5') is connected with a superfine powder storage bin (6') through a pipeline, and the superfine powder storage bin (6') is connected with the primary air pair The pipe (2') communicates, and the outlet of the secondary air pipe (2') communicates with the inlet of the inner primary air pipe (12'); the oil gun (3) passes through the inner primary air pipe (12') And the outer primary air pipe (12), oil gun (3) tail is connected with oil pipe (13); A pipe (7) is connected between the primary air main pipe (2) and the secondary air pipe (2'), and a pipe valve (a) is installed on the pipe (7). The primary air in front of the pipe valve (a) A secondary air pipe valve (b) is installed on the secondary pipe (2'). 2. According to claim 1, the oil-less ignition and combustion system of storage-type coal-fired boiler is characterized in that: a branch pipe (8) is installed on the primary air secondary pipe (2') in front of the secondary air pipe valve (b) , the outlet of the branch pipe (8) extends into the furnace (4), and is located above the outlet of the primary air main pipe (2), and a branch valve (c) is installed on the branch pipe (8). 3. According to claim 1, the oil-less ignition and combustion system of storage-type coal-fired boiler is characterized in that: the furnace (4) is also connected with a secondary air pipe (9), and the outlet of the secondary air pipe (9) Located above the outlet of the primary air main pipe (2). 4. According to claim 1, the oil-less ignition and combustion system of storage-type coal-fired boiler is characterized in that: a ring is arranged on the inner wall near the outlet of the inner primary air pipe (12') near the nozzle of the oil gun (3) Boss (10). 5. According to claim 1, the oil-less ignition and combustion system of storage-type coal-fired boiler is characterized in that: the fine powder separator (5) and the ultrafine powder separator (5') are both cyclone separators, and the fine powder The air outlet pipe of the powder separator (5) communicates with the ultrafine powder separator (5 '), and the air outlet pipe of the ultrafine powder separator (5 ') communicates with the furnace (4), and the ultrafine powder separator Fan (14) is installed on the air outlet pipe of (5 ').

Images