JPH0219372B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention is capable of drying sludge generated from sewage treatment plants, garbage treatment plants, etc., and thermally efficiently melting and converting powdered raw materials such as the obtained dried sludge into slag. This invention relates to a sludge treatment device using a swirling flow combustion melting furnace. (Prior technology) Powder raw materials such as dried sludge, which is made by drying sewage sludge, etc., are placed inside an inclined cylindrical furnace body and are injected in the tangential direction with hot air for combustion, and burned while swirling inside the furnace body. Swirling flow type combustion melting furnaces have been known in the past, in which combustion ash is melted and flowed out from the furnace outlet at the base of the furnace body. Sludge treatment is already being carried out. (Problem to be Solved by the Invention) However, in the conventional swirling flow combustion melting furnace as described above, when the average particle diameter of the powder raw material is less than 50% of the 105μ path, the combustion time becomes longer. The incinerated ash is not completely melted in the furnace and scatters to the flue, causing a blockage of the flue.On the other hand, if the 105μ pass becomes more than 50% fine, it tends to burn in a suspended state, so the incinerated ash becomes a smoke. There was a problem that it could easily spread to the road and cause blockages. Additionally, if the throughput is increased, unburned material is likely to be generated, and conversely, if the throughput is too small, the amount of heat generated inside the furnace decreases, making it impossible to maintain a stable high temperature inside the furnace. Ta. Furthermore, the sludge drying equipment used in combination with the swirl-flow combustion melting furnace emitted a foul odor, which, along with the incinerated ash and unburned materials mentioned above, caused a nuisance to nearby residents. (Means for Solving the Problems) The present invention was completed in order to solve the above-mentioned conventional problems, and provides a sludge treatment device that combines a sludge drying device and a swirling flow combustion melting furnace. In a swirl-flow combustion melting furnace, a raw material injection tube is installed at the front end of an inclined cylindrical furnace body with a burner at the tip to inject the powdered raw material onto hot combustion air in a tangential direction into the inside of the furnace body. In addition, a hot air injection pipe for injecting hot air for combustion in the same direction as the swirling flow generated by the injection is provided at a position near the furnace outlet at the base of the furnace body, and a hot air injection pipe for combustion is provided at the base of the furnace body. This method is characterized in that air containing dry air generated from a sludge drying device is used as the hot air, and the air volume is set to be less than the air volume of the combustion hot air from the raw material injection pipe. Next, the present invention will be explained in detail with reference to examples. (Example) Fig. 1 is a partially cutaway perspective view showing a swirling flow type combustion melting furnace used in the present invention, in which 1 is a slanted cylindrical furnace body, 2 is a furnace body 1 provided at its tip. The burner 2 is equipped with an oil supply pipe 3, a compressed air supply pipe 4 for pressure-feeding oil, and a compressed air supply pipe 5 for oil combustion. 1 into the inside of the furnace body 1. Reference numeral 6 denotes a raw material injection pipe installed in a tangential direction to the inner wall of the furnace body 1 at the front end of the furnace body 1 near the burner 2, and is used to inject powder raw materials such as dried sludge obtained by drying sewage sludge etc. into the fan. The furnace is equipped with a raw material supply pipe 7 for supplying raw material through a combustion chamber and a hot air supply pipe 8 for supplying hot air for combustion, and the powder raw material is carried on the hot air for combustion and is injected into the interior of the furnace body 1 in a tangential direction. The powder raw material and hot air for combustion injected in this way are burned by the heat of the burner 2 while swirling inside the furnace body 1, and the incineration ash is melted and turned into slag, and the furnace body has a reduced cross section. It will flow downward from the furnace outlet 9 at the base, and at a position close to the furnace outlet 9, about 30 mm to 250 mm, hot combustion air with a high temperature of about 300 to 500°C is generated by the swirling air generated by the above injection. A hot air injection pipe 10 is provided which sprays in the same direction as the flow. This hot air injection pipe 10 is used to form an air curtain of hot air in a portion of the furnace body 1 near the furnace outlet 9 to prevent unburned materials and unmelted incineration ash from flowing out of the furnace. The wind speed is set to be the same as or higher than the combustion hot air blown from the hot air supply pipe 8 to counter the swirling flow, and the air volume is set to be equal to or higher than the combustion hot air blown from the hot air supply pipe 8 so as not to disturb the swirling flow. Use the same amount to half the amount of hot air. In addition, 11 is a flue for exhaust gas, and 12 is a molten slag discharge port formed below the furnace outlet part 9. Fig. 2 shows a sludge treatment device that combines the above-mentioned swirl flow type combustion melting furnace and sludge drying device, in which 20 is a dehydrated sludge storage tank, 21 is a dehydrated sludge feeder, and 22 is a hot air pulverized drying type sludge. Drying device, 23
24 is a crushing hammer, 24 is a classifier, 25 is a bag filter, 26 is a dehumidifying tower, 27 is a heat exchanger, and 28 is a molten slag crystallization device. As will be described later, air containing dry air generated from the sludge drying device 22 is used as the combustion hot air ejected from the hot air injection pipe 10 of the swirling flow combustion melting furnace. (Function) In the device configured as described above, the dehydrated sludge stored in the dehydrated sludge storage tank 20 is dried, crushed, and classified by the sludge drying device 22, and the powder raw material, which is the classified dry sludge, is transferred to the bag filter 25. The dried air is collected by a blower 29 and sent to the raw material supply pipe 7, and the dried air separated by a bag filter 25 is sent to a dehumidifying tower 26 and a heat exchanger 27 by a blower 30, where it is heated to 400 to 500°C by exhaust gas. A part of it goes to the hot air supply pipe 8, the other part goes to the hot air injection pipe 10, and the rest goes to the hot air crushing type sludge dryer 22.
It is sent to. The powder raw material is then tangentially injected into the furnace body 1 from the raw material injection pipe 6 at the front end of the slanted cylindrical furnace body 1 on hot air for combustion, forming a swirling flow inside the furnace body 1. While rotating, the incinerated ash is burned by the heat of the burner 2 at the tip of the furnace body 1, and the incinerated ash is also melted by the high temperature inside the furnace, becoming molten slag, and heading toward the furnace outlet 9 at the base of the furnace body 1. Move and go. However, in the present invention, a hot air injection pipe 1 that injects combustion hot air less than the amount of combustion hot air from the hot air supply pipe 8 in the same direction as the swirling flow at a position close to the furnace outlet 9.
0 is provided to form a high-temperature air curtain without interfering with the swirling flow, so even if the particle size of the powder raw material is coarse or when you want to increase the throughput, unburned and unmelted materials can be removed. Incineration ash is captured by this air curtain and burned and melted, and is not discharged to the flue 11 as it is. In addition, even when the particle size of the powder raw material is fine, the incineration ash floating in the swirling flow is similarly captured by this air curtain, and even when the throughput is small and the amount of heat generated in the furnace is small, the incineration ash inside the furnace is Since the temperature is maintained at a stable high temperature by the combustion hot air injected from the hot air injection pipe 10, the powder raw material is completely turned into molten slag and flows out to the molten slag discharge port 12. Furthermore, in the present invention, since air containing dry air generated from the sludge drying device 22 is used as the hot air for combustion in the hot air injection pipe 10, malodorous components in this dry air are decomposed in the furnace. , the exhaust gas released into the atmosphere from the swirl-flow combustion melting furnace is odorless. In order to measure the effects of the present invention, the following experiment was conducted. First, moisture 76-80%, ignition reduction 60%, calorific value
A dehydrated cake of 3000 Kcal/Kg of sewage sludge was put into a hot air pulverization drying type sludge dryer at a rate of 170 Kg/H, and was dried and pulverized to obtain a powder material with an average moisture content of 5%. This is 500φ× which is preheated at 1000℃.
700 into the furnace body at a rate of 50 to 80 kg/H,
The slag collection rate was measured by changing conditions such as the amount of combustion hot air injected from the hot air injection pipe and the temperature inside the furnace. The results are shown in the table below. In the table, the air volume ratio is the air volume from the hot air injection pipe 10/the air volume from the raw material injection pipe 6 in Nm ³ /H, and the average particle size in Table 2 is the ratio of the 105 μ path in %. It is something.

【table】

[Table] (Effects of the Invention) As is clear from the above explanation, the present invention can always perform stable melting regardless of the particle size of the powder raw material or the increase or decrease in the throughput, and it can eliminate unburned materials and It is extremely effective in preventing pollution because it can prevent clogging of the flue due to incineration ash scattering into the flue, and it can also thermally decompose the air containing malodorous components generated from the sludge drying equipment. Therefore, the present invention greatly contributes to the development of industry by eliminating the problems of conventional sludge treatment equipment using a swirling flow type combustion melting furnace.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing a swirling flow type combustion melting furnace used in the present invention, and FIG. 2 is a layout explanatory diagram of a sludge treatment apparatus using the swirling flow type combustion melting furnace of the present invention. 1: Furnace body, 2: Burner, 6: Raw material injection pipe,
9: Furnace outlet section, 10: Hot air injection pipe, 22: Sludge drying device.

Claims (1)

[Claims] 1 In a sludge treatment device that combines a sludge drying device and a swirling flow combustion melting furnace, the swirling flow combustion melting furnace supplies powder raw material to the front part of an inclined cylindrical furnace body 1 equipped with a burner 2 at the tip. A raw material injection pipe 6 that injects tangentially into the inside of the furnace body 1 on hot air for combustion
It has a structure in which a hot air injection pipe 10 for injecting hot air for combustion in the same direction as the swirling flow generated by the above injection is provided at a position near the furnace outlet part 9 at the base of the furnace body 1, and Air containing dry air generated from the sludge drying device 22 is used as hot air for combustion in the pipe 10, and the air volume is adjusted to the raw material injection pipe 6.
A sludge treatment device using a swirling flow combustion melting furnace, characterized in that the amount of hot air for combustion is less than or equal to the amount of hot air for combustion.