JPH04108131U - Combustion gas mixing structure in garbage incinerator - Google Patents

Abstract

(57) [Summary] [Configuration] A grate-type waste incinerator equipped with a primary combustion chamber (1) equipped with a grate (7) and a secondary combustion chamber (2) connected above it. , the secondary combustion chamber (2) has been enlarged,
This combustion gas mixing structure in a waste incinerator is characterized in that the secondary combustion chamber outlet (14) is provided biased toward the rear. [Effect] A vortex is formed near the entrance of the secondary combustion chamber, and at the exit of the secondary combustion chamber, the combustion gas flow along the front wall and the combustion gas flow along the rear wall collide, and as a result, the combustion gas Since the mixture is well-mixed, the flame, unburned components, and surplus air are efficiently mixed, and complete combustion is promoted. Therefore, the unburned content in the exhaust gas containing dioxin precursors such as hydrocarbons is drastically reduced, the generation of dioxin is prevented, and the exhaust gas containing very little or no dioxin can be released into the atmosphere.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This idea relates to garbage incinerators used for incinerating municipal waste, industrial waste, etc. More specifically, we are developing a new structure for combustion furnaces that effectively mixes the combustion gas inside the furnace. It is related to

0002 In this specification, the hopper side refers to the front and the gas discharge path side refers to the front and back. The rear, that is, the left side in FIG. 1 will be referred to as the front, and the right side will be referred to as the rear.

0003

[Conventional technology]

A conventional grate-type waste incinerator has a primary combustion chamber equipped with a grate (7), as shown in Figure 4. An inverted U-shape is formed by a partition wall (9) above the combustion chamber (1) and the primary combustion chamber (1). A secondary combustion chamber (2) and a gas exhaust system that guides the combustion gas generated in the secondary combustion chamber (2) to the flue (3). Exhaust heat recovery device installed near the flue (3) in the exit path (4) and the gas exhaust path (4) (5) and an exhaust gas cooling heat exchanger (6). At the entrance of the secondary combustion chamber (2) is equipped with a secondary air supply nozzle (8).

0004 The garbage (R) in the hopper (10) is placed on the grate (7) and is fed from below the grate (7). The combustion is carried out by the supplied primary air, and the secondary combustion chamber (2) has a secondary air supply nozzle. Secondary air is supplied from the nozzle (8).

[0005] The combustion gas generated by incinerating the garbage (R) is shown by the solid line and the solid line in Figure 4. As shown by the dotted lines, the secondary combustion rises from the primary combustion chamber (1) and goes almost straight. Enter the chamber (2), pass through the gas exhaust path (4), and pass through the exhaust heat recovery device (5) and heat exchanger (6). After being cooled, it is discharged from the flue (3) and sent to an exhaust gas treatment device (not shown). It looks like this.

[0006]

[Problem that the idea aims to solve] However, when incinerating waste using the above-mentioned incinerator, the following problems arise. There is.

[0007] In other words, the secondary combustion chamber (2) is formed into an inverted U-shape by the partition wall (9) as described above. Therefore, the combustion gas from the primary combustion chamber (1) flows through the ascending path of the secondary combustion chamber (2). Climb along the wall and then descend from the top down the path. Meanwhile, the temperature of the combustion gas The degree decreases as the flow moves from upflow to downflow. In addition, the outlet temperature of the primary combustion chamber (1) The effects are clinker formation due to ash melting, shortened refractory life, grate burnout, N Due to problems such as the generation of Ox, it is not possible to raise the temperature to over 1000℃, which is suitable for combustion. Flaws are usually kept below 900°C.

[0008] Therefore, the secondary combustion chamber (2) has a residence time of 2 seconds or more for the purpose of complete combustion. However, the gas temperature decreases as it moves downstream. By nozzle (8) Even if secondary air is supplied to the inlet of the secondary combustion chamber (2), this air will not mix with the combustion gas. When reaching the oxidation region, the oxidation reaction slows down because the gas temperature has decreased as described above. complete combustion is difficult to achieve. As a result, carbon monoxide, hydrocarbons, and soot The unburned components such as these will be emitted as is along with the combustion exhaust gas.

[0009] Additionally, the gas flow in the secondary combustion chamber (2) is close to the so-called piston flow. , the combustion of garbage changes depending on the amount of input garbage, fluctuations in calorific value, changes in the form of garbage, etc. It fluctuates suddenly, often resulting in a momentary air shortage, and in this case too. Unburned substances such as carbon monoxide, hydrocarbons, and soot are emitted along with the exhaust gas. this field The reason is that in piston flow gas flow, the upstream combustion gas and downstream combustion gas mix. This is due to the fact that the above-mentioned momentary air shortage condition occurs because the air conditioner is not maintained.

0010 Hydrocarbons contained in large amounts in exhaust gas are so-called dioxin precursors. A substance that reacts with chlorides such as hydrogen chloride gas in the wake, producing highly toxic dioxin. There is a problem in generating .

[0011] The purpose of this invention was to solve the above problems and to dispose of municipal waste and industrial waste in waste incinerators. To provide a garbage incinerator that can prevent the generation of unburned materials when incinerating waste, etc. There are many things.

0012

[Means to solve the problem]

This idea was devised to achieve the above objective, and the secondary combustion chamber was specially designed. Based on the knowledge that combustion gas can be mixed effectively by having a certain structure. It was completed by

[0013] In other words, this idea consists of a primary combustion chamber equipped with a grate and a combustion chamber connected above it. In a grate-type waste incinerator equipped with a secondary combustion chamber, the secondary combustion chamber is expanded. and the outlet of the secondary combustion chamber is biased toward the rear. This is the combustion gas mixing structure in an incinerator.

[0014] In a preferred embodiment of this invention, in the structure of the above configuration, the outlet of the secondary combustion chamber is In the mouth, the anterior wall slopes downward relative to the horizontal plane and the posterior wall slopes forward relative to the vertical plane. It is slanted in the direction. Here, the front wall is covered with water at the outlet of the secondary combustion chamber. The angle of inclination with the plane is preferably 0 to 60 degrees, and the rear wall at the outlet of the secondary combustion chamber is The angle of inclination between the front wall and the vertical plane is preferably 0 to 60 degrees, and more preferably the front wall The flow direction of combustion gas flowing along the rear wall and the flow direction of combustion gas flowing along the rear wall. are in opposite directions and their respective inclination angles are set so that the combustion gas flows collide in opposite directions. It can be decided. Further, secondary air is supplied to at least one of the inlet and outlet of the secondary combustion chamber. A supply nozzle is provided.

[0015] The gas temperature at the inlet of the secondary combustion chamber is preferably 1150-850°C, more preferably Preferably, the temperature is in the range of 1000 to 900°C.

[0016]

[Effect]

In the waste incinerator of this invention, the secondary combustion chamber is enlarged, and the secondary combustion chamber is enlarged. Since the combustion chamber outlet is biased toward the rear, combustion gas rising from the primary combustion chamber The gas flow is separated into a straight upward flow and a flow along the front and rear walls of the secondary combustion chamber. , a vortex is formed near the inlet of the secondary combustion chamber. Straight up in the secondary combustion chamber The combustion gas collides with the front wall of the secondary combustion chamber, changes its flow direction, and becomes the secondary combustion chamber. At the exit of the grilling chamber, a collision occurs between the combustion gas flow along the front wall and the combustion gas flow along the rear wall. This results in better mixing of the combustion gases.

[0017]

【Example】

Next, this invention will be specifically explained with reference to illustrated embodiments.

[0018] In Figure 1, the waste incinerator according to this invention has a primary combustion chamber equipped with a grate (7). (1), a secondary combustion chamber (2) connected above the primary combustion chamber (1), and a primary combustion chamber (1). hopper (10) that leads to the hopper (10), and a gas exhaust passage (4) that leads combustion gas from the secondary combustion chamber (2) to the flue. It is equipped with

[0019] The secondary combustion chamber (2) is enlarged, and the secondary combustion chamber outlet (14) is biased toward the rear. It is provided.

[0020] The front wall (11) and rear wall (12) of the secondary combustion chamber (2) each have an arc-shaped vertical cross section, and At the outlet of the next combustion chamber (14), the front wall (11) is inclined downward with respect to the horizontal plane, and the rear wall (12) is inclined forward with respect to the vertical plane.

[0021] In addition, secondary air supply nozzles are installed at the inlet (13) and outlet (14) of the secondary combustion chamber (2). (8) is provided.

[0022] The garbage (R) in the hopper (10) is placed on the grate (7) provided in the combustion chamber (1). It is burned using primary air supplied from below the grate (7). secondary combustion Secondary air is supplied to the baking chamber (2) from a secondary air supply nozzle (8).

[0023] In the above configuration, the combustion gas flow rising from the primary combustion chamber (1) is The flow is divided into a flow rising toward the top and a flow along the front wall (11) and rear wall (12) of the secondary combustion chamber (2). They are separated, and a vortex is formed near the secondary combustion chamber inlet (13). Stroke inside the secondary combustion chamber (2) The combustion gas that has risen to a high rate collides with the front wall (11) of the secondary combustion chamber and changes its flow direction. At the secondary combustion chamber outlet (14), the combustion gas flow along the front wall (11) and the rear wall (1 2) Collision of the combustion gas flows occurs, resulting in good mixing of the combustion gases.

[0024] The secondary air supply nozzle (8) is installed at the inlet (13) and outlet (14) of the secondary combustion chamber (2). Since it is possible to supply secondary air to the combustion gas mixing section, the combustion gas mixing is promoted.

[0025] When the combustion gases are well mixed in this way, carbon monoxide, hydrocarbons, soot, etc. The fuel is completely combusted in the vortex, and combustion is completed extremely quickly.

[0026] Also, carbon monoxide and hydrocarbons coming from the momentary air shortage caused by piston flow. Emissions of unburned substances such as soot and soot are caused by the mixture of upstream combustion gas and downstream combustion gas. As a result, it has been drastically reduced.

[0027] 2 and 3 show a modification of the secondary combustion chamber of this invention.

[0028] First, in the example of Fig. 2, the front wall (15) and rear wall (16) of the secondary combustion chamber (2) are respectively The vertical cross section is approximately arcuate, and the front wall (15) is asymmetrically larger than the rear wall (16). At the outlet of the next combustion chamber (14), the front wall (15) is inclined downward with respect to the horizontal plane, and the rear wall (16) is inclined forward with respect to the vertical plane. In this way, the first order Combustion gas rising from the combustion chamber (1) has a straight upward flow and secondary combustion. The flow is separated into the flow along the front wall (15) and the rear wall (16) of the chamber (2), and the flow is separated into the flow along the front wall (15) and the rear wall (16) of the chamber (2). A vortex is formed nearby. The combustion gas that rises straight inside the secondary combustion chamber (2) , collides with the front wall (15) of the secondary combustion chamber and changes its flow direction, causing the secondary combustion chamber outlet (15) to change its flow direction. In 4), the combustion gas flow is made to make a large turn along the front wall (15) and the flow is made along the rear wall (16). Impingement of the combustion gas streams takes place, resulting in good mixing of the combustion gases.

[0029] In the example in Figure 3, the front wall (17) and rear wall (18) of the secondary combustion chamber (2) each have a vertical section. It has a polygonal shape with an asymmetrical shape in which the front wall (17) is larger than the rear wall (18), and the secondary combustion At the chamber exit (14), the front wall (17) is inclined downward with respect to the horizontal plane, and the rear wall (18) is vertical. It is tilted forward with respect to the surface. In this way, the primary combustion chamber The combustion gas rising from (1) flows straight upward and into the secondary combustion chamber (2). The flow is separated into the flow along the front wall (17) and the rear wall (18), and the flow near the secondary combustion chamber entrance (13). A vortex is formed. The combustion gas that rises straight inside the secondary combustion chamber (2) is It collides with the front wall of the combustion chamber (17), changes its flow direction, and flows into the secondary combustion chamber outlet (14). The combustion gas flow is largely detoured along the front wall (17) and the combustion gas flow is routed along the rear wall (18). Impingement of the gas streams takes place, resulting in good mixing of the combustion gases.

[0030] CO concentration at each point in the incinerator with and without supplying secondary air The results of the measurements are shown in Table 1 below. However, the secondary The combustion chamber inlet temperature is maintained in the range of 950-900°C.

[0031]

[Table 1]

[0032] Incidentally, the inclination angle A that the front wall makes with the horizontal plane at the outlet of the secondary combustion chamber is preferably The angle of inclination B that the rear wall makes with the vertical plane at the outlet of the secondary combustion chamber is preferably between 0 and 60 degrees. preferably 0 to 60 degrees, more preferably the flow of combustion gas flowing along the front wall The combustion gas flow direction is opposite to the flow direction of the combustion gas flowing along the rear wall. The inclination angles of each are determined so that the two collide oppositely.

[0033]

[Effect of the idea]

According to the waste incinerator of this invention, when a vortex is formed near the entrance of the secondary combustion chamber, In both cases, at the exit of the secondary combustion chamber, combustion gas flows along the front wall and combustion gas flows along the rear wall. Flow impingement occurs, resulting in good mixing of the combustion gases, so that the flame and unburnt The mixture of air and surplus air is efficiently carried out, promoting complete combustion. therefore , the amount of unburned matter in exhaust gas containing dioxin precursors such as hydrocarbons is drastically reduced. Prevents the generation of dioxin and contains only trace amounts of dioxin or no dioxin Exhaust gas can be released into the atmosphere.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing one specific example of a garbage incinerator according to the invention.

FIG. 2 is a vertical cross-sectional view showing the main parts of a specific example of the garbage incinerator according to the invention.

FIG. 3 is a vertical cross-sectional view showing the main parts of one specific example of the garbage incinerator according to the invention.

FIG. 4 is a vertical sectional view showing a conventional garbage incinerator.

[Explanation of symbols]

(1)…Primary combustion chamber (2) …Secondary combustion chamber (14)...Secondary combustion chamber outlet

Continuation of front page (72) Creator Kohei Hamabe Hitachi, 5-3-28 Nishikujo, Konohana-ku, Osaka Within Shipbuilding Co., Ltd. (72) Creator Kazuo Ieyama Hitachi, 5-3-28 Nishikujo, Konohana-ku, Osaka Within Shipbuilding Co., Ltd. (72) Creator Mamoru Kondo Hitachi, 5-3-28 Nishikujo, Konohana-ku, Osaka Within Shipbuilding Co., Ltd.

Claims (1)

[Scope of utility model registration request] [Claim 1] A primary combustion chamber (1) equipped with a grate (7);
In a grate-type waste incinerator equipped with a secondary combustion chamber (2) connected above the incinerator, the secondary combustion chamber (2) is enlarged, and the secondary combustion chamber outlet (14) is located at the rear. A combustion gas mixing structure in a garbage incinerator characterized by being installed unevenly in the