CN111981449A - Waste heat boiler for burning high-sulfur and high-halogen hazardous wastes - Google Patents

Abstract

The invention discloses a waste heat boiler for the incineration of high-sulfur and high-halogen hazardous waste, comprising: a furnace body, the furnace body includes a first temperature region and a second temperature region, and the temperature of the first temperature region is higher than temperature in the second temperature region; water cooling walls, a plurality of the water cooling walls are provided in the furnace body, wherein one or more of the water cooling walls are located in the first temperature region, and one or more of the water cooling walls are located in the first temperature region. is located in the second temperature region; wherein, the water-cooled wall is composed of pipes and a connecting mechanism between pipes, and a cladding layer is provided on the flue gas side of the water-cooled wall located in the first temperature region. According to the waste heat boiler for the incineration of high-sulfur and high-halogen hazardous wastes provided by the present invention, by setting a cladding layer on the flue gas side of the water-cooled wall in the high-temperature area of the waste heat boiler, the flue gas generated by the incineration of high-sulfur and high-halogen hazardous wastes is avoided. Corrosion of water wall by medium alkaline salts.

Description

A waste heat boiler for incineration of high-sulfur and high-halogen hazardous waste

technical field

The invention relates to the field of hazardous waste treatment, in particular to a waste heat boiler used for the incineration of high-sulfur and high-halogen hazardous wastes.

Background technique

Hazardous waste is corrosive and infectious, and the harmful substances contained in it will cause damage to the ecological environment such as air, soil, and water sources. With the development of science and technology, the disposal methods of hazardous waste have gradually increased, including physical disposal, solidification disposal, incineration disposal, landfill disposal, etc. However, no matter what disposal method is adopted, in the process of disposal, we must always adhere to the The principle of reduction, harmlessness and resource utilization”.

At present, incineration is the most commonly used hazardous waste disposal method in my country. With the rapid development of the national economy, high-sulfur and high-halogen hazardous wastes have increased. During the incineration process of high-sulfur and high-halogen hazardous wastes, alkaline salts (such as NaCl and KCl) will be partially vaporized. In the waste heat boiler, according to the vapor pressure at high temperature And deposited on the water wall, causing the water wall to corrode. Especially when the chlorine content of the hazardous waste is greater than 5%, the corrosion degree of the water cooling wall increases rapidly, and the higher the temperature of the pipe wall, the more serious the corrosion.

Therefore, it is necessary to propose a new waste heat boiler for the incineration of high-sulfur and high-halogen hazardous wastes to solve the above problems.

SUMMARY OF THE INVENTION

A series of concepts in simplified form have been introduced in the Summary section, which are described in further detail in the Detailed Description section. The Summary of the Invention section of the present invention is not intended to attempt to limit the key features and essential technical features of the claimed technical solution, nor is it intended to attempt to determine the protection scope of the claimed technical solution.

The invention provides a waste heat boiler for incineration of high-sulfur and high-halogen hazardous waste, comprising:

a furnace body, the furnace body includes a first temperature zone and a second temperature zone, the temperature of the first temperature zone is higher than the temperature of the second temperature zone;

a water-cooling wall, wherein a plurality of the water-cooling walls are arranged in the furnace body, wherein one or more of the water-cooling walls are located in the first temperature region, and one or more of the water-cooling walls are located in the second temperature region;

Wherein, the water-cooling wall is composed of pipes and a connecting mechanism between pipes, and a cladding layer is provided on the flue gas side of the water-cooling wall in the first temperature region.

Further, the cladding layer is made of high-temperature and anti-corrosion materials.

Further, the deposited layer includes a nickel-cobalt-chromium-silicon alloy.

Further, the cladding layer is formed by a coaxial powder feeding laser cladding process.

Further, the dilution rate for forming the cladding layer is less than or equal to 3%.

Further, the thickness of the cladding layer is greater than or equal to 1 mm.

Further, the temperature of the first temperature region is higher than 650°C, and the temperature of the second temperature region is lower than 650°C.

Further, the side wall of the furnace body is provided with a flue gas inlet and a flue gas outlet, the first temperature area is close to the flue gas inlet, and the second temperature area is close to the flue gas outlet.

Further, a plurality of the water cooling walls are staggered in the furnace body to form a serpentine-curved flue between the flue inlet and the flue outlet.

According to the waste heat boiler for the incineration of high-sulfur and high-halogen hazardous wastes provided by the present invention, by setting a cladding layer on the flue gas side of the water-cooled wall in the high-temperature area of the waste heat boiler, the flue gas generated by the incineration of high-sulfur and high-halogen hazardous wastes is avoided. Corrosion of water walls by vaporized alkaline salts.

Description of drawings

The following drawings of the present invention are incorporated herein as a part of the present invention for understanding of the present invention. The accompanying drawings illustrate embodiments of the present invention and their description, which serve to explain the principles of the present invention.

In the attached picture:

FIG. 1 is a schematic structural diagram of a waste heat boiler for incineration of high-sulfur and high-halogen hazardous wastes according to an embodiment of the present invention.

2 is a cross-sectional view of a water wall according to one embodiment of the present invention.

100 furnace bodies

101 Flue gas inlet

102 Flue gas outlet

200 Water Wall

201 Pipes

202 Connection mechanism

Detailed ways

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without one or more of these details. In other instances, some technical features known in the art have not been described in order to avoid obscuring the present invention.

For a thorough understanding of the present invention, a detailed description will be presented in the following description to illustrate the waste heat boiler for the incineration of high-sulfur and high-halogen hazardous wastes of the present invention. Obviously, the practice of the present invention is not limited to specific details familiar to those skilled in the art of hazardous waste treatment. Preferred embodiments of the present invention are described in detail below, however, the present invention may have other embodiments in addition to these detailed descriptions.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments in accordance with the present invention. As used herein, the singular forms are also intended to include the plural forms unless the context clearly dictates otherwise. Furthermore, it should also be understood that when the terms "comprising" and/or "comprising" are used in this specification, they indicate the presence of stated features, integers, steps, operations, elements and/or components, but do not exclude the presence or Addition of one or more other features, integers, steps, operations, elements, components and/or combinations thereof.

Now, exemplary embodiments according to the present invention will be described in more detail with reference to the accompanying drawings. These exemplary embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of these exemplary embodiments to those skilled in the art. In the drawings, the thicknesses of layers and regions are exaggerated for clarity, and the same reference numerals are used to denote the same elements, and thus their descriptions will be omitted.

The hazardous waste incineration treatment system generally includes a pretreatment unit, an incineration unit, a waste heat recovery unit, a flue gas purification unit, and the like. Among them, in the pretreatment unit, liquid, mud-like solids and solid wastes in containers are analyzed, processed, mixed according to their calorific value, whether they contain halide, water content and other indicators, and then put into the incineration unit in a controlled manner. Incineration units are used to incinerate hazardous waste to minimize organic compounds and the resulting ash and gas residues. The incineration unit generally includes a rotary kiln and a secondary combustion chamber, wherein the rotary kiln is mainly used to vaporize, decompose and burn most of the organic substances, and the secondary combustion chamber is mainly used to oxidize all organic substances and waste gas, and the waste gas includes the rotary kiln burning hazardous waste. flammable gases produced. The waste heat recovery unit mainly recovers the heat in the flue gas through the waste heat boiler, and can further utilize the heat to generate economic benefits (such as power generation). The flue gas purification unit is mainly used to purify the flue gas through various devices, so that the discharged flue gas meets the domestic and foreign emission standards.

In view of the high sulfur and high halogen hazardous waste in the prior art, the alkaline salt is easily vaporized during the incineration process and then deposited on the water wall in the waste heat boiler, causing corrosion of the water wall, and with the increase of the halogen content in the hazardous waste and the temperature of the water wall. If the increase is higher, the more serious the corrosion is, the present invention proposes a waste heat boiler for the incineration of high-sulfur and high-halogen hazardous wastes, as shown in Figure 1, including:

A furnace body 100, the furnace body 100 includes a first temperature region and a second temperature region, and the temperature of the first temperature region is higher than the temperature of the second temperature region;

A water cooling wall 200, a plurality of the water cooling walls 200 are arranged in the furnace body 100, wherein one or more of the water cooling walls 200 are located in the first temperature region, and one or more of the water cooling walls 200 are located in the the second temperature region

Wherein, the water-cooling wall 200 is composed of pipes and a connecting mechanism between pipes, and a cladding layer is provided on the flue gas side of the water-cooling wall 200 located in the first temperature region.

Exemplarily, the furnace body 100 is constructed of refractory masonry. Further, the surface of the furnace body 100 is provided with heat insulating material to reduce heat loss.

As shown in FIG. 1 , the side wall of the furnace body 100 is provided with a flue gas inlet 101 and a flue gas outlet 102 . In one embodiment, the flue gas inlet 101 and the flue gas outlet 102 are both arranged on the upper part of the furnace body 100, and the flue gas generated by the incineration of high-sulfur and high-halogen hazardous waste in the incineration unit passes through the flue gas The inlet 101 enters the waste heat boiler. At this time, the temperature of the flue gas is very high, about 1100°C. The flue gas flows through the flue formed by the water-cooled wall 200. As the flue gas exchanges heat with the cold fluid in the water-cooled wall, the flue gas flows continuously. The temperature is gradually lowered and then discharged from the flue gas outlet 102 .

According to the temperature change of the flue gas in the waste heat boiler, the furnace body 100 can be divided into a first temperature area and a second temperature area, wherein the first temperature area is close to the flue gas inlet 101, and the second temperature area Close to the flue gas outlet 102, therefore, the temperature of the first temperature region is higher than the temperature of the second temperature region. As an example, the temperature of the first temperature zone is higher than 650°C, and the temperature of the second temperature zone is lower than 650°C.

Exemplarily, the furnace body 100 is provided with a plurality of water cooling walls 200 .

In one embodiment, as shown in FIG. 1 , a plurality of the water cooling walls 200 are staggered in the furnace body 100 , wherein one end of one or more water cooling walls 200 is fixed on the top of the furnace body 100 , and one One end of one or more water cooling walls 200 is fixed on the bottom of the furnace body 100 to form a serpentine curved flue between the flue inlet 101 and the flue outlet 102 .

By forming a serpentine curved flue between the flue inlet 101 and the flue outlet 102, the distance and time of the flue gas flowing in the waste heat boiler are prolonged, so that the flue gas and the cold fluid in the water wall can fully exchange heat , reducing the volume of the waste heat boiler and improving the heat exchange efficiency of the waste heat boiler.

As shown in FIG. 2 , the water cooling wall 200 is composed of pipes 201 and a connecting mechanism 202 between pipes, and the material of the water cooling wall 200 is iron-carbon alloy (eg, carbon steel).

Exemplarily, the pipe 201 is a hollow pipe. In one embodiment, the flue gas flows through the flue gas side (eg, the outer side) of the water wall 200, and the cold fluid (eg, water) flows through the cold fluid side (eg, the inner side) of the water wall 200, through Heat exchange recovers the heat in the flue gas and then uses it.

Exemplarily, the inter-pipe connection mechanism 202 is a flat steel, so as to connect the multiple pipes 201 constituting the water-cooling wall 200 without gaps, so as to prevent the flue gas from passing through between the pipes of the water-cooling wall 200, so that the smoke The gas flows along the serpentine curved flue formed by the staggered arrangement of the water walls.

Exemplarily, a cladding layer is provided on the flue gas side of the water cooling wall 200 located in the first temperature region.

Exemplarily, the cladding layer is made of high-temperature and anti-corrosion materials.

Further, the deposited layer includes a nickel-cobalt-chromium-silicon alloy. As an example, the average contents of nickel, cobalt, chromium, and silicon in the nickel-cobalt-chromium-silicon alloy are 37%, 29%, 27%, and 2.8%, respectively.

In one embodiment, the cladding layer adopts HAYNES HR-160 alloy, HR-160 alloy is a solid solution strengthened nickel-cobalt-chromium-silicon alloy, which has excellent resistance to various high-temperature corrosion damages and has excellent reducibility Resistant to sulfidation and chloride attack in oxidizing atmospheres. HR-160 alloy can withstand high temperature of 1205℃, and shows high strength and good anti-oxidation and corrosion resistance at high temperature of 650℃-1100℃.

Due to the high content of vaporized alkaline salts (such as NaCl and KCl) in the flue gas generated from the incineration of high-sulfur and high-halogen hazardous wastes, and the temperature in the first temperature region is relatively high, through all the processes in the first temperature region The cladding layer provided on the flue gas side of the water cooling wall 200 can prevent the low melting point chloride salt deposited on the water cooling wall 200 from converting iron into highly volatile ferric chloride, thereby avoiding corrosion of the water cooling wall 200 .

Exemplarily, the cladding layer is formed by a coaxial powder feeding laser cladding process.

In one embodiment, the dilution rate for forming the cladding layer is less than or equal to 3%, and the thickness of the cladding layer formed is greater than or equal to 1 mm.

The coaxial powder feeding laser cladding process usually adopts a semiconductor fiber output laser and a disc-type air-borne powder feeder. Special protective gas channel, powder beam, light beam and protective airflow intersect at one point. During the cladding work, a molten pool will be formed at the focal point, and with the relative movement of the cladding head and the workpiece, a cladding layer will be formed on the surface of the workpiece.

The coaxial powder feeding laser cladding process has the following advantages: (1) High degree of freedom and easy automation. Due to the use of axisymmetric powder feeding head, it can move to any direction during welding to obtain a deposited layer with the same morphology and the same quality, and the welding direction is not limited. The height of the deposition can also be adjusted by adjusting the focal length of the light spot and the height of the powder aggregation focus. (2) The protection effect of inert gas in the molten pool is good. Because the powder feeding method is airborne powder feeding and a special inert gas flow channel is arranged on the welding head, the molten pool is in a good local inert gas atmosphere during the welding process, the molten pool and the welding layer are less oxidized, and the welding There are fewer oxide inclusions in the layer. (3) The molten pool is small, the powder is heated evenly, and the cladding layer has good crack resistance. The spot size of coaxial powder feeding laser cladding is generally ∮1mm-∮5mm, the powder is in uniform contact with the beam, and the heat transfer during the cladding process is more uniform, so the cladding layer has good crack resistance. (4) Small penetration and low heat input. Coaxial powder-feeding laser cladding has a small spot diameter and high cladding line speed. Compared with wide-spot lateral powder-feeding laser cladding and arc welding, the cladding heat input is low, with moderate dilution rate and less thermal influence. The depth of the zone, the deposition performance is excellent, and the influence on the performance of the base metal is small.

According to the waste heat boiler for the incineration of high-sulfur and high-halogen hazardous wastes provided by the present invention, by setting a cladding layer on the flue gas side of the water-cooled wall in the high-temperature area of the waste heat boiler, the flue gas generated by the incineration of high-sulfur and high-halogen hazardous wastes is avoided. Corrosion of water walls by vaporized alkaline salts.

The present invention has been described by the above-mentioned embodiments, but it should be understood that the above-mentioned embodiments are only for the purpose of illustration and description, and are not intended to limit the present invention to the scope of the described embodiments. In addition, those skilled in the art can understand that the present invention is not limited to the above-mentioned embodiments, and more variations and modifications can also be made according to the teachings of the present invention, and these variations and modifications all fall within the protection claimed in the present invention. within the range. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (9)

1. A waste heat boiler for incineration of high sulfur and high halogen hazardous waste, comprising:

the furnace body comprises a first temperature area and a second temperature area, and the temperature of the first temperature area is higher than that of the second temperature area;

the furnace body is internally provided with a plurality of water-cooled walls, wherein one or more water-cooled walls are positioned in the first temperature area, and one or more water-cooled walls are positioned in the second temperature area;

the water-cooled wall is composed of pipelines and a connecting mechanism between the pipelines, and a fusion coating layer is arranged on the smoke side of the water-cooled wall in the first temperature area.

2. The exhaust-heat boiler as recited in claim 1, characterized in that the cladding layer is made of a high-temperature resistant and corrosion-resistant material.

3. The exhaust-heat boiler of claim 2, wherein the cladding layer comprises a nickel-cobalt-chromium-silicon alloy.

4. The exhaust-heat boiler according to claim 3, characterized in that the cladding layer is formed by a coaxial powder-feeding laser cladding process.

5. The exhaust-heat boiler according to claim 4, characterized in that the dilution ratio for forming the cladding layer is less than or equal to 3%.

6. The exhaust-heat boiler according to claim 1, characterized in that the thickness of the cladding layer is greater than or equal to 1 mm.

7. A waste heat boiler as claimed in claim 1, characterized in that the temperature of the first temperature zone is above 650 ℃ and the temperature of the second temperature zone is below 650 ℃.

8. The exhaust-heat boiler according to claim 7, characterized in that a flue gas inlet and a flue gas outlet are arranged on the side wall of the furnace body, the first temperature zone is close to the flue gas inlet, and the second temperature zone is close to the flue gas outlet.

9. The waste heat boiler as claimed in claim 8, wherein a plurality of said water walls are staggered within said furnace body to form a serpentine flue between said flue inlet to said flue outlet.

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