CN202915349U - Water-coal-slurry burning liquid-state deslagging cyclone furnace capable of achieving low ash burning - Google Patents

Abstract

The utility model relates to low _NOx combustion technology, and aims to provide a water-fired coal slurry liquid slag discharge cyclone furnace for realizing low-ash combustion. The equipment includes a columnar furnace body, and the coal-water slurry burner on the top of the furnace body has a hollow pre-combustion zone; the coal-water slurry inlet and the primary air inlet are arranged above the pre-combustion zone, and the wall of the coal-water slurry burner Secondary air nozzles are set; the furnace in the furnace body is divided into main combustion zone, reburning zone and burnout zone from top to bottom, upper tangential secondary air nozzles are set in the middle and upper part of the main combustion zone, and lower cutting nozzles are set in the lower part of the main combustion zone. To the secondary air nozzle, the reburning fuel nozzle is provided in the reburning area, and the burnout air nozzle is provided in the burnout area; the flue gas outlet is provided on the bottom side of the furnace, and the slag outlet is provided at the bottom of the furnace. The equipment operates graded air distribution and reburning technology during the combustion process, which can reduce 60% of NOx emissions; the setting of each air distribution nozzle enables the combustion of coal-water slurry to be carried out in the simplest and most economical way, which is in the industry The above application has a good application prospect.

Description

Water-fired coal slurry liquid slagging cyclone furnace for low ash combustion

technical background

The utility model relates to a low _NOx combustion technology, in particular to a water-fired coal slurry liquid slag discharge cyclone furnace for realizing low ash combustion.

Background technique

With the rapid development of the economy, people's demand for energy is also increasing. Coal, oil and natural gas are the three pillars of the world's primary energy. As a strategic resource, oil plays an important role in national defense and security. With the development of industrialization, the domestic demand for oil is gradually increasing. Although my country is a big oil-producing country, most of our oil still depends on imports. Internationally, rising fluctuations in international oil prices will make countries all over the world compete for oil, and as oil is gradually consumed, this worldwide competition will become more intense. However, my country's natural gas resources are relatively poor, and natural gas accounts for only 3% of primary energy consumption. However, the demand for natural gas will increase day by day, and the price of natural gas will also continue to rise. Industrial gas-fired boilers are facing tremendous pressure from rising costs. At the same time, the "Eleventh Five-Year Plan" clearly pointed out that during the "Eleventh Five-Year Plan" period, the energy consumption per unit of GDP will be reduced by about 20%, which makes industrial gas-fired boilers face transformation. my country is a big coal country with abundant coal resources. When oil and natural gas prices continue to rise, coal-water slurry is a low-sulfur, low-ash clean fuel with high combustion efficiency. The thermal efficiency of coal-water slurry boilers is higher than that of coal-fired boilers. height of. The development of coal water slurry to replace oil and gas has good economic value.

Pollutants emitted by fuel combustion are the main part of air pollutants, and NOx produced by combustion is one of the main components that cause acid rain. China's economic development is very rapid, but at the cost of huge energy consumption, the ensuing environmental problems are not optimistic. China's total NOx emissions ranged from 12.1*10 ⁶ t in 2000 to 19.1*10 ⁶ t in 2005 , with an annual growth rate of 10%, so it is imperative to reduce NOx emissions. The "Twelfth Five-Year Plan" also regards reducing the emission of nitrogen oxides as the top priority of improving the quality of the atmospheric environment.

Utility model content

The technical problem to be solved by the utility model is to overcome the deficiencies in the prior art, and provide a water-fired coal slurry liquid slagging cyclone furnace that realizes low-ash combustion.

For solving technical problems, the solution of the utility model is:

A coal-water slurry liquid slagging cyclone furnace for realizing low-ash combustion is provided, which includes a columnar furnace body; a coal-water slurry burner is arranged on the top of the furnace body, and its main body has horizontally extending edges and a convex center , forming a hollow pre-combustion zone; above the pre-combustion zone, there are coal-water slurry inlets and primary air inlets, and secondary air nozzles are set on the wall of the coal-water slurry burner; the furnace in the furnace body is divided into main combustion chambers from top to bottom. zone, reburning zone and burnout zone, upper tangential secondary air nozzles are set in the middle and upper part of the main combustion zone, lower tangential secondary air nozzles are set in the lower part of the main combustion zone, reburning fuel nozzles are set in the reburning zone, and combustion air nozzles are set in the burnout zone. Air-exhausting nozzles; flue gas outlets are set on the side of the bottom of the furnace, and slag outlets are set on the bottom of the furnace.

As an improvement, there are 10 secondary air nozzles, which are arranged at intervals in a clockwise direction on the wall of the pre-combustion zone at preset angles.

As an improvement, the upper tangential secondary air nozzles are arranged on the inner wall of the furnace in two layers, two in each layer.

As an improvement, the lower tangential secondary air nozzles are arranged on the inner wall of the furnace in two layers, with 2 to 8 nozzles in each layer.

The beneficial effects of the utility model are:

The liquid slagging cyclone furnace in the utility model can reduce 60% of NOx emissions by running the graded air distribution and reburning technology in the combustion process; the setting of each air distribution nozzle makes the combustion of coal water slurry the simplest and It is carried out in the most economical way, which has a good application prospect in industrial application.

Description of drawings

Fig. 1 is a schematic structural diagram of a cyclone furnace for liquid slag removal by burning coal-water slurry.

Reference signs: 1 coal water slurry inlet, 2 primary air inlet, 3 secondary air nozzle, 4 upper tangential secondary air nozzle, 5 lower tangential secondary air nozzle, 6 reburning fuel nozzle, 7 burnout air nozzle, 8 Slag outlet, 9 pre-combustion zone, 10 main combustion zone, 11 reburning zone, 12 burnout zone.

Detailed ways

Embodiments of the utility model are described below in conjunction with the accompanying drawings.

In this embodiment, the coal-water slurry liquid slagging cyclone furnace for low-ash combustion includes a columnar furnace body; a coal-water slurry burner is arranged on the top of the furnace body, and its main body has horizontally extending edges and a raised center shape, forming a hollow pre-combustion zone 9; a coal-water slurry inlet 1 and a primary air inlet 2 are provided above the pre-combustion zone 9, and a secondary air spout 3 is established on the wall of the coal-water slurry burner; Divided into the main combustion zone 10, the reburning zone 11 and the burnout zone 12 from the bottom, the upper tangential secondary air nozzle 4 is set in the middle and upper part of the main combustion zone 10, and the lower tangential secondary air nozzle 5 is set in the lower part of the main combustion zone 10 , the reburning zone 11 is provided with a reburning fuel nozzle 6 (the reburning fuel uses natural gas), the burnout zone 12 is provided with an overburning air nozzle 7;

There are 10 secondary air nozzles 3, which are arranged on the wall of the coal-water slurry burner at intervals in a clockwise direction at preset angles. There are 4 upper tangential secondary air nozzles 4, which are arranged in two layers on the inner wall of the furnace, and each layer has two air outlets. The lower tangential secondary air nozzles 5 are arranged on the inner wall of the furnace in two layers, with 2 to 8 nozzles in each layer. In this combustion system, coal-water slurry is sprayed into the furnace at a certain speed to form atomized particles. The primary air enters the furnace at a certain tangential velocity through the cyclone device.

There are three formation mechanisms of NOx: temperature-type NOx, fuel-type NOx, and rapid temperature-type NOx.

(1) Temperature-type NOx. It means that the nitrogen in the air undergoes an oxidation reaction at a high temperature exceeding 1500C. The higher the temperature, the more NOx is produced. If the flame temperature in the local area is very high, a large amount of NOx will be produced, and this part of NOx accounts for 10%~20% of the total NOx. To reduce the temperature-type NOx, the combustion is required to be at a lower combustion level. The temperature distribution of the flame is uniform. The graded air distribution proposed by the utility model can distribute and feed air in an appropriate amount along the flame stroke, and can effectively suppress the generation of NOx.

(2) Fuel-type NOx. It refers to the thermal decomposition and oxidation of nitrogen in fuel to generate NOx. Furthermore, it is mainly to direct the nitrogen compounds in the exhaust to generate NOx, which accounts for 80% to 90% of the total NOx, and this part of NOx is produced in the flame center at the outlet of the burner. To control the amount of NOx produced in this area, the excess air ratio at the initial stage of fuel ignition should be controlled. The pulverized coal is in an oxygen-deficient state at the beginning of ignition, and part of the volatile NOx is reduced. The amount of air introduced in the pre-combustion chamber 9 proposed in the utility model is 20% of the total amount, so that the excess air coefficient of the fuel is far less than 1 at the initial stage of ignition.

(3) Rapid temperature NOx. It means that the nitrogen in the air and the hydrocarbon fuel react at high temperature to generate intermediate products N, NCH, CN, etc., and then quickly react with oxygen, and the generated NOx accounts for 5% of the total.

The specific implementation process:

CWS has certain requirements on fire conditions. When the coal-water slurry is on fire, high-temperature flue gas is needed to quickly gasify the water in the coal-water slurry, and the dry coal powder is heated. Therefore, a pre-combustion zone 9 is set on the upper part of the furnace to ensure that the coal-water slurry and air can be fully mixed. At the same time, in the pre-combustion zone 9, both the primary air and the secondary air of the pre-combustion chamber are small, and the excess air coefficient is less than 1.

The atomized coal-water slurry particles and air are mixed into the main combustion zone 10, and most of them are burned in this zone, because the combustion temperature and combustion intensity of the liquid slagging cyclone furnace are high, and the volatile matter in the pulverized coal volatilizes quickly and quickly The released volatiles can reduce the formation of NOx. Through the graded air distribution technology, the upper and lower tangential secondary air nozzles 4 and 5 are arranged on the upper and lower sides of the furnace to delay the mixing of fuel and air, so that oxygen is gradually added to the combustion, and the high temperature and low oxygen environment can suppress the generation of NOx .

When pulverized coal entered the reburning zone 11, most of the fuel had been burned. At this time, a certain amount of natural gas is injected into the reburning fuel nozzle in the lower part of the furnace, so that the fuel can be completely burned in this area, and the injected natural gas consumes the remaining oxygen from the main combustion area 10 to form a reducing area. The NOx in the combustion zone 10 is reduced, and the high temperature environment is conducive to the discharge of liquid slag.

When the high-temperature flue gas enters the burnout zone 12, a certain amount of burnout air is introduced to make the combustion complete.

Claims (3)

1. realize the low grey combusting coal water slurry slag tap cyclone furnace that burns for one kind, comprise the body of heater of column, it is characterized in that, be provided with water coal slurry burner on the top of body of heater, the water coal slurry burner main body has horizontally extending edge and the center is convex, forms the preignition zone of hollow; Above preignition zone, be provided with water-coal-slurry entrance and a wind entrance, establish overfire air port on the wall of water coal slurry burner; Burner hearth in the body of heater is divided into primary zone, reburning zone and burning-out zone from top to bottom, establishes tangential overfire air port in the middle and upper part in primary zone, and tangential overfire air port is set in the bottom in primary zone, and the reburning fuel spout is established in the reburning zone, and burning-out zone is established the after-flame wind snout; Exhanst gas outlet is established in the burner hearth bottom side, and burner hearth bottom sets out cinder notch.

2. combusting coal water slurry slag tap cyclone furnace according to claim 1 is characterized in that, described tangential overfire air port divides two-layer layout to be arranged on the inboard wall of burner hearth, 2 every layer.

3. combusting coal water slurry slag tap cyclone furnace according to claim 1 is characterized in that, described lower tangential overfire air port divides two-layer layout to be arranged on the inboard wall of burner hearth, 2～8 every layer.

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