CN107559819A - A kind of spiral-flow powdered coal burning mechanism that gradually expanded form precombustion chamber is carried for Industrial Boiler - Google Patents

Abstract

A kind of spiral-flow powdered coal burning mechanism that gradually expanded form precombustion chamber is carried for Industrial Boiler, the present invention relates to a kind of spiral-flow powdered coal burning mechanism, the present invention is limited to solve the mediumand smallscale industrial boilers of coal dust burning in the prior art by size of burner hearth and combustion system, and NOx discharge is high, the problem of precombustion chamber easy slagging, it includes vortex burner and precombustion chamber, the madial wall of precombustion chamber is set by arrival end to the port of export in gradually expanded form, the port of export of vortex burner and the arrival end of precombustion chamber connect, and the port of export of vortex burner is concordant with the entrance of precombustion chamber is correspondingly arranged, the industrial field of boilers of the present invention.

Description

A swirl pulverized coal combustion mechanism with expanding pre-combustion chamber for industrial boilers

technical field

The invention relates to an industrial boiler pulverized coal combustion mechanism, in particular to a swirling pulverized coal combustion mechanism with a gradually expanding pre-combustion chamber for an industrial boiler.

Background technique

In my country, coal-fired industrial boilers are the main coal-consuming equipment except power plant boilers, with a total of nearly 600,000 units and an annual coal consumption of nearly 640 million tons. In recent years, with the development of pulverized coal processing, transportation and storage technology, and the continuous maturity of pulverized coal combustion technology, small and medium-sized industrial boilers using pulverized coal have been continuously developed. However, limited by the size of the furnace and the combustion method, the existing small and medium-sized industrial pulverized coal boilers have problems such as high NOx emissions and easy slagging in the pre-combustion chamber. With the increasingly severe environmental protection problems in our country, it will be difficult to meet the increasingly stringent environmental protection standards if effective solutions are not taken to the existing problems of industrial pulverized coal boilers.

The pulverized coal combustion device with pre-combustion chamber currently used in our country, such as the utility model patent "An Inferior Coal Pre-combustion Chamber Burner with Anti-Slagging" (Chinese Patent No. ZL201320145975.4, authorized announcement date is March 2014 On February 26, the application publication number is CN203501168U, hereinafter referred to as "Document 1"), the wall of the pre-combustion chamber is divided into four sections, the first section is gradually expanding, the last three sections are straight, and the secondary air flows from the wall The gap between them is sprayed in three sections, the first two sections are sprayed against the wall, and the third section is sprayed obliquely. Utility model patent "A burner for pulverized coal pre-combustion chamber with extended section" (Chinese patent number is ZL201320724053.9, date of authorization announcement is September 24, 2014, application publication number is CN203848280U, hereinafter referred to as "Document 2 ”), the pre-chamber body is divided into an inlet end and an outlet end, the inlet end of the pre-chamber body is cylindrical and is used for installing the main burner, and the outlet end of the pre-chamber body is gradually expanding . The pre-combustion chamber proposed in "Document 1" adopts the form of the front section gradually expanding and the rear section straight cylinder; the "Document 2" proposes the pre-chamber adopting the form of the front section straight cylinder and the rear section gradually expanding.

Contents of the invention

The present invention aims to solve the problems that the small and medium-sized industrial boilers using pulverized coal in the prior art are limited by the size of the furnace and the combustion method, as well as the problems of high NOx emissions and easy slagging in the pre-combustion chamber, and further provides a belt boiler for industrial boilers. A swirling pulverized coal combustion mechanism with a gradually expanding pre-combustion chamber.

The technical scheme that the present invention adopts for solving the above problems is:

It includes a swirl pulverized coal burner and a pre-combustion chamber, the inner wall of the pre-combustion chamber is gradually expanded from the inlet end to the outlet end, the outlet end of the swirl pulverized coal burner is connected with the inlet end of the pre-combustion chamber, and The outlet end of the swirl pulverized coal burner is flush with the inlet of the pre-combustion chamber and arranged correspondingly.

The beneficial effects of the present invention are:

(1) The present invention is conducive to reducing the amount of NOx generation

① The burner described in "Document 2" adopts a pre-combustion chamber with a straight cylinder at the front and a gradual expansion at the rear. The straight cylinder at the front restricts the full development of the airflow, which is not conducive to the formation of the recirculation zone. Compared with the comparison "Document 2", the device of the present invention adopts a gradually expanding pre-combustion chamber, which is beneficial to the formation of the central recirculation zone, and sprays high-concentration pulverized coal from the center of the burner into the high-temperature central recirculation zone of a low-oxygen and strong reducing atmosphere. Combustion of pulverized coal in a fuel-rich and low-oxygen atmosphere for a long time is beneficial to suppress the formation of NOx.

②The burner described in "Document 1" adopts a pre-combustion chamber in the form of a straight cylinder in the front section that gradually expands in the rear section, and the straight cylinder section at the rear end is not conducive to the full development of the airflow. Compared with the comparison "Document 1", the pre-combustion chamber of the device of the present invention is gradually expanded, which is conducive to the development of the swirling airflow, delays the mixing of the internal and external secondary air, strengthens the air staged combustion degree of the burner, and delays the secondary airflow. The mixing of secondary air and pulverized coal airflow is beneficial to reduce the formation of fuel-type NOx. At the same time, the use of a gradually expanding pre-combustion chamber is conducive to the formation of the central recirculation zone. The stable central recirculation zone keeps the pulverized coal in a reducing atmosphere for a long time, which is beneficial to suppress the formation of NOx.

(2) The present invention is beneficial to avoid slagging in the pre-combustion chamber

① The burner described in "Document 1" adopts a pre-combustion chamber in the form of a straight cylinder in the front section gradually expanding and a rear section. The straight cylinder section at the rear end is not conducive to the airflow to bring ash and slag out of the pre-combustion chamber. Other measures need to be taken to solve the ash accumulation in the pre-combustion chamber and the problem of slagging. Compared with the comparison "Document 1", all the pre-combustion chambers of the device of the present invention are gradually expanded, and driven by the rotating jet, the ash on the wall can be effectively blown out of the pre-combustion chamber. Simultaneously, the length of the pre-combustion chamber of the device of the present invention is only set as 0.8 to 2 times of the external diameter of the secondary air pipe outside the swirling flow, and the length of the pre-combustion chamber is short, which is conducive to blowing out the pre-combustion chamber by the pulverized coal flue gas flow in the pre-combustion chamber, avoiding Slagging in pre-chamber.

②The device of the present invention concentrates the particles into the center of the burner and injects them to prevent pulverized coal from being thrown onto the wall of the pre-combustion chamber by the secondary air, thereby effectively avoiding the occurrence of slagging and high-temperature corrosion in the pre-combustion chamber.

(3) The present invention is beneficial to the ignition and stable combustion of pulverized coal

① The device of the present invention is provided with a pre-combustion chamber so that the stable ignition and combustion of the pulverized coal airflow can be maintained even when the load is low or the coal quality is deteriorating. At the same time, the pre-combustion chamber of the device of the present invention is gradually expanded, which is beneficial to the formation of the central recirculation zone, where the high-temperature flue gas in the entrainment furnace in the central recirculation zone heats the pulverized coal airflow, and the stable central recirculation zone ensures the ignition of the pulverized coal and stable combustion.

②The device of the present invention feeds the high-concentration pulverized coal airflow from the center of the burner, so that all the pulverized coal injected into the furnace is concentrated in the high-temperature central recirculation zone, forming a high-temperature and high-concentration zone in the central recirculation zone, prolonging the life of the pulverized coal in the furnace. The residence time in the high temperature zone strengthens the ignition and stable combustion performance of the pulverized coal flow, enabling the boiler to operate at a lower load, and the combustion stability can also be fully guaranteed.

Description of drawings

FIG. 1 is a schematic diagram of the device of the present invention arranged on the front wall 3 of a horizontal boiler, and the central recirculation area 5 is located at the entrance of the pre-combustion chamber 2 .

FIG. 2 is a schematic diagram of the arrangement of the device of the present invention on the roof 4 of the vertical boiler, and the central recirculation area 5 is located at the entrance of the pre-combustion chamber 2 .

detailed description

Specific Embodiment 1: This embodiment is described in conjunction with Fig. 1-Fig. 2. The swirl pulverized coal combustion mechanism for an industrial boiler with a gradually expanding pre-combustion chamber described in this embodiment includes a swirl pulverized coal combustion mechanism. Device 1 and pre-combustion chamber 2, the inner wall of pre-combustion chamber 2 is gradually expanded from the inlet end to the outlet end, the outlet end of swirl pulverized coal burner 1 is connected with the inlet end of pre-combustion chamber 2, and the swirl flow The outlet end of the pulverized coal burner 1 is arranged flush with the inlet of the pre-combustion chamber 2 .

Specific embodiment two: This embodiment is described in conjunction with Fig. 1-Fig. 2, a swirl pulverized coal combustion mechanism for an industrial boiler with a gradually expanding pre-combustion chamber described in this embodiment, a swirl pulverized coal burner 1 Including the primary air duct 1-1, the secondary air duct 1-2 in the swirl flow, the secondary air duct 1-3 outside the swirl flow, the first axial swirl blade 1-4 and the second axial swirl blade 1- 5. The secondary air pipe 1-3 outside the swirl flow and the secondary air pipe 1-2 inside the swirl flow are set on the primary air pipe 1-1 in turn from the outside to the inside, and the primary air pipe 1-1, the second air pipe inside the swirl flow The secondary air duct 1-2 and the secondary air duct 1-3 outside the swirl flow are coaxially arranged, and the first axial swirl blade 1-4 is arranged on the primary air duct 1-1 and the secondary air duct 1-2 inside the swirl flow Between them, the second axial swirl vanes 1-5 are arranged between the inner swirl secondary air duct 1-2 and the swirl outer secondary air duct 1-3, and the others are the same as in the first embodiment.

The pulverized coal airflow is sprayed out through the primary air duct 1-1 in the center of the swirling pulverized coal burner 1, and the secondary airflow forms a rotating jet under the action of the axial swirling blades and enters the pre-combustion chamber 2, and the rotating jet is formed in the center of the airflow In the reflow zone, the high-temperature flue gas in the entrainment furnace heats up and ignites the pulverized coal flow.

Specific embodiment three: this embodiment is described in conjunction with Fig. 1-Fig. 2, a kind of swirl pulverized coal combustion mechanism that is used for industrial boiler with expanding pre-combustion chamber described in this embodiment, the inlet end of pre-combustion chamber 2 There is an expansion angle to the exit end, and the angle of the expansion angle is α, and the value range of α is 0-10. Others are the same as in the first embodiment.

Specific embodiment four: This embodiment is described in conjunction with Fig. 1-Fig. 2, a kind of swirl pulverized coal combustion mechanism that is used for industrial boiler with expanding pre-combustion chamber described in this embodiment, pre-combustion chamber 2 is made of high-strength The refractory material is poured into the pre-combustion chamber. Others are the same as in the first embodiment.

Specific embodiment five: This embodiment is described in conjunction with Fig. 1-Fig. 2, a kind of swirl pulverized coal combustion mechanism that is used for industrial boilers with a gradually expanding pre-combustion chamber described in this embodiment, the diameter of the inlet end of the pre-combustion chamber 2 It is 1.5 times to 3 times the outer diameter of the secondary air pipe 1-3 outside the swirling flow, and the length of the pre-combustion chamber 2 is 0.8 times to 2 times the outer diameter of the secondary air pipe 1-3 outside the swirling flow. Others are the same as the specific embodiment one, two, three or four.

Claims (5)

1. A kind of swirl pulverized coal burning mechanism that is used for industrial boiler with gradually expanding pre-combustion chamber, it is characterized in that: it comprises swirl pulverized coal burner (1) and pre-combustion chamber (2), pre-combustion chamber The inner wall of (2) is gradually expanded from the inlet end to the outlet end, and the outlet end of the swirl pulverized coal burner (1) is connected with the inlet end of the pre-combustion chamber (2), and the swirl pulverized coal burner ( The outlet end of 1) is flush with the inlet of the pre-chamber (2) and correspondingly arranged. 2. A kind of swirl pulverized coal combustion mechanism that is used for industrial boilers with a gradually expanding pre-combustion chamber according to claim 1, characterized in that: the swirl pulverized coal burner (1) includes a primary air duct (1- 1), the secondary air duct (1-2) in the swirl flow, the secondary air duct (1-3) outside the swirl flow, the first axial swirl blade (1-4) and the second axial swirl blade ( 1-5); the secondary air pipe (1-3) outside the swirl flow and the secondary air pipe (1-2) inside the swirl flow are sleeved on the primary air pipe (1-1) from outside to inside in turn, and the primary air The pipe (1-1), the secondary air pipe (1-2) inside the swirl flow and the secondary air pipe (1-3) outside the swirl flow are coaxially arranged, and the first axial swirl blade (1-4) is arranged on Between the primary air duct (1-1) and the secondary air duct (1-2) in the swirl flow, the second axial swirl vane (1-5) is arranged in the secondary air duct (1-2) in the swirl flow And between the secondary air pipe (1-3) outside the swirling flow. 3. according to claim 1, a kind of swirl pulverized coal combustion mechanism that is used for industrial boilers with a gradually expanding pre-combustion chamber is characterized in that: the inlet end of the pre-combustion chamber (2) has an expansion angle to the outlet end, The spread angle is α, and the range of α is 0-10°. 4. According to claim 1, a kind of swirling pulverized coal combustion mechanism for industrial boilers with a gradually expanding pre-combustion chamber is characterized in that: the pre-combustion chamber (2) is formed by casting high-strength refractory materials. combustion chamber. 5. according to claim 1, 2, 3 or 4 described a kind of swirling flow pulverized coal combustion mechanism that is used for industrial boiler with gradually expanding pre-combustion chamber, it is characterized in that: the diameter of pre-combustion chamber (2) inlet end is 1.5 to 3 times the outer diameter of the secondary air pipe (1-3) outside the swirling flow, and the length of the pre-combustion chamber (2) is 0.8 to 2 times the outer diameter of the secondary air pipe (1-3) outside the swirling flow .