A high-halogen hazardous waste incineration treatment process

Abstract

The present application relates to hazardous waste incineration processing technical field, specifically relates to a kind of high halogen hazardous waste incineration processing technology, comprising the following steps: (1) according to the total amount of halogen molecular of high halogen hazardous waste 65%~90% addition base earth metal oxide powder is mixed to be treated material;(2) select and match the remaining residue rate is 5%~13%, and the ash melting point is 1000~1100 DEG C, and the thermal value is complementary with high halogen hazardous waste, and the treated material is mixed to obtain compatible material;(3) the compatible material is put into rotary kiln incineration, and moisture and flue gas are diffused from rotary kiln to continue burning in secondary combustion chamber;(4) burnout flue gas enters waste heat boiler to recover heat and denitrate, and after tail purification device, it is discharged up to standard.The present application is combined into salt by using base earth metal ion and halogen ion, improves the disposal efficiency of high halogen hazardous waste, avoids halogen ion to form hydrogen halide acid gas under high temperature, and the problems caused by it, such as flue corrosion, tail gas exceeds acid removal load and even tail gas over discharge.

Description

Technical Field

[0001] This invention relates to the field of hazardous waste incineration technology, specifically to an incineration process for high-halogen hazardous waste. Background Technology

[0002] With the development of industrialization, hazardous waste treatment has received increasing attention. Hazardous waste refers to solid and liquid waste that possesses one or more hazardous characteristics, such as corrosivity, toxicity, flammability, reactivity, or infectivity, or may possess hazardous characteristics, and may have harmful effects on the environment or human health, and therefore needs to be managed as hazardous waste.

[0003] Currently, incineration is the primary method for hazardous waste treatment. This method utilizes the oxidation and pyrolysis of toxic and harmful substances in the waste at high temperatures to destroy them, achieving a significant degree of harmlessness and volume reduction, while also recovering waste heat. The conventional process for hazardous waste incineration is as follows: after mixing and blending, the waste enters a rotary kiln for combustion to obtain primary flue gas. This primary flue gas then enters a secondary combustion chamber for combustion to obtain secondary flue gas. The secondary flue gas then passes through a waste heat boiler for heat recovery, is cooled by a rapid cooling deacidification tower, and then passes through a dry reaction unit for the adsorption of dioxins and heavy metals by slaked lime and activated carbon. A bag filter removes dust, a wet deacidification tower removes waste acid, and a flue gas heater raises the temperature before finally discharging through a chimney.

[0004] To ensure compliance with exhaust emission standards, equipment lifespan, and normal system operation, strict requirements are placed on the halogen content, especially the fluorine and chlorine content, during material formulation. Excessive fluorine and chlorine content can easily lead to system flue corrosion and shorten service life. Furthermore, incineration will generate large amounts of hydrogen fluoride, hydrogen chloride, and chlorine, causing dioxins and acidic gases to exceed standards in the exhaust gas. Chinese patent CN112212335A discloses a hazardous waste incineration process and system, requiring that the halogen mass fraction per kilogram of hazardous waste be below 2%, preferably below 1%. However, the fluorine and chlorine content in hazardous waste from the pesticide and chemical industries is constantly increasing, with halogen content reaching up to 10%, making conventional processes insufficient to meet treatment requirements. Summary of the Invention

[0005] To address the problems of flue corrosion, exceeding the deacidification load, and even excessive emissions of exhaust gas when incinerating hazardous waste with high halogen content using existing treatment processes, this invention provides an incineration treatment process for high-halogen hazardous waste, the specific technical solution of which includes the following steps:

[0006] (1) Add alkaline earth metal oxide powder to the high-halogen hazardous waste at 65% to 90% of the total halogen molecules and mix well to obtain the material to be treated; (2) Select a batching material with a residual slag rate of 5% to 13%, a slag ash melting point of 1000 to 1100℃, and a calorific value that is complementary to that of the high-halogen hazardous waste, and mix it with the material to be treated to obtain a batching material; (3) Put the batching material into a rotary kiln for incineration, and the moisture and flue gas diffuse from the rotary kiln to the secondary combustion chamber for continued combustion; (4) The flue gas after combustion enters the waste heat boiler to recover heat and denitrify, and passes through a quench tower, a dry reaction device, a bag filter, a two-stage wet desulfurization system and an electrostatic precipitator in sequence before being discharged in compliance with standards.

[0007] Adding alkaline earth metal oxide powder ensures that there are sufficient alkaline ions in the incinerated material to replace hydrogen ions and combine with halide ions, producing solid salts. This reduces the generation of chlorine, hydrogen chloride, and hydrogen fluoride, thereby alleviating the corrosive effect on the flue and the deacidification burden on subsequent processes.

[0008] Furthermore, in step (1), the halogen content of the high-halogen hazardous waste is 10% to 25%.

[0009] Furthermore, in step (1), the alkaline earth metal oxide is calcium oxide or magnesium oxide.

[0010] Furthermore, in step (2), liquid hazardous waste is added and stirred until evenly mixed.

[0011] Furthermore, in step (2), the amount of ingredients used is 1 to 3 times the total amount of high-halogen hazardous waste.

[0012] Furthermore, in step (3), the temperature of the kiln head area of ​​the rotary kiln is 850-880℃, and the temperature of the kiln tail area is 950-980℃.

[0013] Furthermore, observe the condition of the material at the kiln tail through the kiln tail observation port and slag remover. If there is molten bottom salt or coking, raise the kiln tail temperature to 1000℃ and put foamed bricks or compressed iron drums with a diameter of 15-25cm into the rotary kiln.

[0014] Furthermore, in step (3), the temperature of the secondary combustion chamber is 1100-1150℃.

[0015] Furthermore, the pH of the alkaline solution in the two-stage wet deacidification system is maintained at 7.5–8.5, and 1%–2% reducing agent is added to the alkaline solution. The addition of a reducing agent to the alkaline solution can dissolve water-insoluble BrO₂. X It is converted to HBr, which enhances the debromination ability.

[0016] Furthermore, in step (4), the pH, salt content and reducing power of the two-stage wet deacidification system are checked every 3 to 4 hours. When the salt content exceeds 5%, 10% of the total amount of alkali solution in the system needs to be replaced.

[0017] The beneficial effects of this invention are as follows:

[0018] The incineration process for high-halogen hazardous waste provided by this invention improves the disposal efficiency of high-halogen hazardous waste by utilizing the combination of alkaline earth metal ions and halogen ions to form salts, and avoids the formation of hydrogen halide acidic gas by halogen ions at high temperatures, as well as the resulting problems of flue corrosion, tail gas exceeding the deacidification load, and even tail gas over-emission. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0020] Example 1

[0021] An incineration process for treating high-halogen hazardous waste includes the following steps:

[0022] (1) The hazardous waste generated by a certain unit has a total halogen content of 10% by mass fraction, a residual slag rate of 3%, a TDS of 10%, a calorific value of 20000kJ / kg, and a slag ash melting point of 900℃. It is a high-halogen hazardous waste. Calcium oxide powder is added at 65% of the total halogen molecules and mixed evenly using a mixing equipment to obtain the material to be treated.

[0023] (2) Select materials and liquid hazardous waste with a residue rate of 5% to 13%, a slag ash melting point of 1000 to 1100℃, and a calorific value complementary to that of high-halogen hazardous waste, including activated carbon filter residue, activated sludge, distillation residue, cation exchange resin, sludge, rubber hoses, paint residue, oil sludge, etc. The amount of materials used is 1.5 times the total amount of high-halogen hazardous waste. Mix them with the material to be treated to obtain a compatibility material. The calorific value of the compatibility material is 15000kJ / kg, the total halogen molecule content is 3%, and the TDS is 20%.

[0024] (3) The mixed materials are fed into the rotary kiln for combustion via the crane grab bucket-chain conveyor-feeding port. As the kiln rotates, the bottom material slowly moves from the kiln head area at 850°C to the kiln tail area at 950°C. Moisture and flue gas diffuse from the rotary kiln to the secondary combustion chamber and continue to burn at 1100°C. The condition of the material at the kiln tail is observed through the kiln tail observation port and the slag remover. The molten bottom salt or coking is normal.

[0025] (4) The flue gas after combustion enters the waste heat boiler to recover heat and remove nitrate. After passing through the quench tower, dry reaction device, bag filter, two-stage wet desulfurization system and electrostatic precipitator in sequence, it meets the emission standards. The pH of the alkaline solution in the two-stage wet desulfurization system is maintained at 7.5, and 1.5% reducing agent is added to the alkaline solution. The pH, salt content and reducing power of the two-stage wet desulfurization system are checked every 3 hours. When the salt content exceeds 5%, 10% of the total amount of alkaline solution in the system is replaced.

[0026] Comparative Example 1

[0027] (1) The same batch of residual hazardous waste from Example 1 was mixed with chlorine-free hazardous waste. The amount of chlorine-free hazardous waste was 1.5 times the total amount of high-halogen hazardous waste. The mixture was then mixed to obtain the blended material.

[0028] (2) The mixed materials are fed into the rotary kiln for combustion via the crane grab bucket-chain conveyor-feed port. As the kiln rotates, the bottom material slowly moves from the kiln head area at 850°C to the kiln tail area at 950°C. Moisture and flue gas diffuse from the rotary kiln to the secondary combustion chamber and continue to burn at 1100°C.

[0029] (3) The flue gas after combustion enters the waste heat boiler to recover heat and remove nitrate. After passing through the quench tower, dry reaction device, bag filter, two-stage wet desulfurization system and electrostatic precipitator in sequence, it meets the emission standards.

[0030] Compared with Comparative Example 1, Example 1 showed a 30% reduction in alkali consumption in the quench deacidification tower, a 10% reduction in total ash output, a 3% increase in total slag output, and a 5% shortening of the TDS growth cycle in the slag remover water. In the laboratory, the residues from both Example 1 and Comparative Example 1 were found to be loose and lumpy after combustion. No hydrogen chloride was detected in the exhaust gas from either Example 1 or Comparative Example 1.

[0031] Example 2

[0032] An incineration process for treating high-halogen hazardous waste includes the following steps:

[0033] (1) The hazardous waste generated by a certain unit has a total halogen content of 25% by mass fraction, a residual slag rate of 3%, a TDS of 10%, a calorific value of 20000kJ / kg, and a slag ash melting point of 900℃. It is a high-halogen hazardous waste. Calcium oxide powder is added according to 90% of the total halogen molecules, and the mixture is mixed with a mixing device to obtain the material to be treated.

[0034] (2) Select ingredients and liquid hazardous waste with a residue rate of 5% to 13%, a slag ash melting point of 1000 to 1100℃, and a calorific value that complements that of high-halogen hazardous waste, including activated carbon filter residue, activated sludge, distillation residue, cation exchange resin, sludge, rubber hoses, paint residue, oil sludge, etc. The amount of ingredients used is 3 times the total amount of high-halogen hazardous waste. Mix them with the material to be treated to obtain a compatibility material. The calorific value of the compatibility material is 15000kJ / kg, the total halogen molecule content is 3%, and the TDS is 20%.

[0035] (3) The mixed materials are fed into the rotary kiln for combustion via the crane grab bucket-chain conveyor-feeding port. As the kiln rotates, the bottom material slowly moves from the kiln head area at 880°C to the kiln tail area at 980°C. Moisture and flue gas diffuse from the rotary kiln to the secondary combustion chamber and continue to burn at 1150°C. The kiln tail material is observed through the kiln tail observation port and the slag remover. If there is a lot of molten bottom salt or coking, the kiln tail temperature is increased to 1000°C. Foamed bricks or compressed iron drums with a diameter of 15-25cm are added to the rotary kiln to remove the excess bottom salt.

[0036] (4) The flue gas after combustion enters the waste heat boiler to recover heat and remove nitrate. After passing through the quench tower, dry reaction device, bag filter, two-stage wet desulfurization system and electrostatic precipitator in sequence, it meets the emission standards. The pH of the alkaline solution in the two-stage wet desulfurization system is maintained at 8.5, and 2% reducing agent is added to the alkaline solution. The pH, salt content and reducing power of the two-stage wet desulfurization system are checked every 3 hours. When the salt content exceeds 5%, 10% of the total amount of alkaline solution in the system is replaced.

[0037] Compared with Comparative Example 1, Example 2 showed that the alkali consumption of the quench deacidification tower was basically the same. However, Example 2 showed that the total ash output increased by 4%, the total slag output increased by 10%, the TDS growth cycle of the slag remover water was shortened by 12%, and no hydrogen chloride was detected in the exhaust gas discharged from Example 2.

[0038] When the residue from Example 2 was burned in the laboratory, slight clumping occurred, but it did not react violently with water at high temperatures.

[0039] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention.

Claims

1. A process for incineration of high-halogen hazardous waste, characterized in that, It comprises the following steps: (1) adding 65-90% of alkali earth metal oxide powder according to the total amount of halogen molecules in the high-halogen hazardous waste, and mixing to obtain a to-be-treated material; (2) selecting a proportioning material with a residue rate of 5-13%, a residue ash melting point of 1000-1100 DEG C, and a heat value complementary to that of the high-halogen hazardous waste, and mixing with the to-be-treated material to obtain a compatible material; (3) putting the compatible material into a rotary kiln for incineration, the temperature at the kiln head region of the rotary kiln is 850-880 DEG C, and the temperature at the kiln tail region is 950-980 DEG C; observing the material at the kiln tail through the kiln tail observation port and the slag grab, if there is molten bottom salt or coking, increasing the temperature at the kiln tail to 1000 DEG C, and putting foamed bricks or compressed iron skin barrels with a block diameter of 15-25 cm into the rotary kiln, and the moisture and flue gas diffuse from the rotary kiln to the secondary combustion chamber for continued combustion; (4) the burned-out flue gas enters a waste heat boiler to recover heat and denitrate, and is discharged after sequentially passing through a quenching tower, a dry reaction device, a bag-type dust removal device, a two-stage wet acid removal system, and an electrostatic dust removal device; the pH of the lye in the two-stage wet acid removal system is maintained at 7.5-8.5, and 1-2% of a reducing agent is added to the lye, the pH, salt content, and reducing property of the two-stage wet acid removal system are checked every 3-4 h, and when the salt content exceeds 5%, 10% of the total amount of lye in the system is replaced.

2. The incineration process of claim 1, wherein, In step (1), the halogen content of the high-halogen hazardous waste is 10-25%.

3. The incineration process of claim 1 wherein, In step (1), the alkali earth metal oxide is calcium oxide or magnesium oxide.

4. The incineration process of claim 1 wherein, In step (2), a liquid hazardous waste is also added, and the mixture is stirred and mixed uniformly.

5. The incineration process of claim 1 wherein, In step (2), the amount of the proportioning material is 1-3 times the total amount of the high-halogen hazardous waste.

6. The incineration process of claim 1 wherein, In step (3), the temperature of the secondary combustion chamber is 1100-1150 DEG C.