Agricultural and forestry waste and municipal sludge coupling pyrolysis treatment system and treatment method

Abstract

The invention belongs to the field of scientific treatment and utilization of wastes, and discloses a coupling pyrolysis treatment system for agricultural and forestry wastes and municipal sludge, which is characterized in that (1) the municipal sludge is subjected to heat drying and pyrolysis carbonization to be converted into sludge carbon, (2) the agricultural and forestry wastes are subjected to crushing, drying and granulation pretreatment and pyrolysis in-situ activation to be converted into biomass activated carbon, and (3) the biomass activated carbon is subjected to pyrolysis in-situ activation to be converted into biomass activated carbon. (3) heat released by combustion of pyrolysis gas in the pyrolysis in-situ activation treatment process of the agricultural and forestry waste is provided for an agricultural and forestry waste and sludge drying system, and (4) biomass activated carbon is used for a flue gas purification system and sold, and sludge carbon is used as a soil conditioner to be applied to agricultural and forestry waste producing areas. Through coupling pyrolysis of the sludge and the agricultural and forestry waste, the energy supplement problem in the sludge drying pyrolysis process and the energy outlet problem in the agricultural and forestry waste pyrolysis process can be solved, and coupling scientific treatment of the sludge and the agricultural and forestry waste and product recycling are achieved.

Description

Technical Field

[0001] The invention relates to resource processing of agricultural and forestry wastes and municipal sludge, and to a coupled pyrolysis treatment system and a treatment method for agricultural and forestry wastes and municipal sludge. Background Art

[0002] With the increase of organic matter content in sewage sludge and the requirements for harmless, resource-based and low-carbon treatment of sludge, pyrolysis carbonization technology suitable for distributed miniaturization, harmless, resource-based and low-carbon treatment of sludge has gradually received attention and engineering promotion in China. At present, the treatment capacity of sewage plants is mainly small and medium-sized with a capacity of less than 100,000 m3 / d, and the sludge output is basically less than 100 tons (80% water content). However, this distributed small-scale sludge drying-pyrolysis treatment has problems such as insufficient energy, large investment per ton of sludge, and high operating costs per ton, making it difficult to implement the project.

[0003] Agricultural and forestry wastes with high C content and high calorific value, especially woody wastes, are suitable as raw materials for energy and charcoal products. Due to their dispersion and low density, their resource utilization rate is less than 10%, and they currently need scientific disposal and resource utilization. Agricultural and forestry wastes with high C content and dispersion are suitable for distributed pyrolysis carbonization heat-carbon cogeneration technology, which can obtain heat (steam or hot water) and charcoal products, and can be processed and utilized locally, so as to achieve high-quality resource utilization of agricultural and forestry wastes and avoid long-distance transportation. However, the distributed pyrolysis carbonization heat-carbon cogeneration of agricultural and forestry wastes has the disadvantages of large ton investment and high operating costs due to small-scale distribution. At the same time, it is also difficult to utilize the heat (steam or hot water) of the heat-carbon cogeneration locally, resulting in low profits and uneconomical engineering projects, and it is also difficult to implement and promote large-scale projects.

[0004] In summary, sludge pyrolysis faces problems such as insufficient heat for sludge drying and high investment and operating costs due to the lack of utilization of sludge charcoal products. Pyrolysis of agricultural and forestry waste faces problems such as excessive heat production that cannot be fully utilized and poor economic benefits. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a coupled pyrolysis disposal system and method for agricultural and forestry waste and municipal sludge.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A coupled pyrolysis treatment system and method for agricultural and forestry waste and municipal sludge, characterized in that: the whole system comprises two main components: municipal sludge treatment and agricultural and forestry waste treatment;

[0008] The municipal sludge treatment part includes a sludge receiving and storage system, a sludge drying system, a sludge internal heat pyrolysis treatment device, a sludge waste heat utilization system and a flue gas purification system, and each system is connected in sequence;

[0009] The agricultural and forestry waste treatment part includes a biomass receiving and storing system, a biomass crushing system, a biomass drying system, a biomass homogenizing and granulating system, a biomass internal heat pyrolysis and activation treatment device, a biomass waste heat utilization system and a flue gas purification system, and each system is connected in sequence.

[0010] The municipal sludge treatment part consists of the following steps:

[0011] a. The sludge enters from the sludge receiving and storage system and passes through the sludge drying system to reduce the moisture content to below 15%;

[0012] b. After drying, the sludge enters the internal heat pyrolysis treatment device for pyrolysis to produce sludge charcoal;

[0013] c. The high-temperature flue gas generated by the combustion of pyrolysis gas is recycled through the waste heat utilization system to generate steam as the energy source for sludge drying;

[0014] d. The flue gas is discharged through the flue gas purification system after being purified.

[0015] The agricultural and forestry waste treatment part is composed of the following steps:

[0016] a. Agricultural and forestry waste is crushed into debris with a particle size of less than 5mm in the biomass crushing system;

[0017] b. Then enter the biomass drying system to reduce the moisture content to below 15%;

[0018] c. The dried biomass debris enters the uniform granulation system and is made into biomass particles with a particle size of 5 to 8 mm and a length of 3 to 5 cm;

[0019] d. The dried particles enter the internal heat pyrolysis and activation treatment device for pyrolysis and activation to produce biological activated carbon;

[0020] e. The high-temperature flue gas generated by the combustion of pyrolysis gas is recycled through the waste heat utilization system to generate steam as the energy source for biomass drying;

[0021] f. After being purified, the flue gas is discharged through the flue gas purification system.

[0022] The sludge-based biochar produced by drying and pyrolysis of municipal sludge in the municipal sludge treatment part is provided to the agricultural and forestry waste production area for soil improvement and carbon fixation.

[0023] The heat (steam) from the combustion of pyrolysis gas generated by pyrolysis and activation of agricultural and forestry wastes in the agricultural and forestry waste treatment section is provided to the sludge drying system, and the biomass charcoal is used in the flue gas purification system and sold as a charcoal product.

[0024] The beneficial effects of the present invention are:

[0025] In view of the drawbacks of small-scale distributed pyrolysis carbonization of sludge and agricultural and forestry waste, the small-scale municipal sludge pyrolysis carbonization is coupled with the pyrolysis activation of agricultural and forestry waste to make up for the problem of high investment per ton and high operating costs caused by the small scale of separate treatment of sludge and agricultural and forestry waste. The heat of the agricultural and forestry waste heat-carbon cogeneration is used on-site for sludge drying, solving the problem of insufficient energy in the sludge drying pyrolysis system and the problem of the outlet of heat (steam or hot water) in the agricultural and forestry waste heat-carbon cogeneration. In addition, the sludge-based charcoal produced by sludge pyrolysis can be used for soil improvement in agricultural and forestry land, breaking the bottleneck of the application outlet of sludge pyrolysis charcoal, and simultaneously achieving carbon fixation and sink increase. The charcoal products of the agricultural and forestry waste heat-carbon cogeneration can be used on-site for the original system flue gas purification and sold as charcoal products. The present invention can realize the scientific disposal and resource product application of miniaturized sludge and agricultural and forestry waste, and has the effects of reducing pollution, reducing carbon, improving quality, and expanding greening. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The simplified flow chart of one embodiment of the agricultural and forestry waste and municipal sludge coupled pyrolysis system of the present invention. DETAILED DESCRIPTION

[0027] In order to solve the problems existing in the prior art, the present invention provides a coupled pyrolysis disposal system and method for agricultural and forestry waste and municipal sludge, which will be further explained with reference to specific embodiments.

[0028] Example 1

[0029] Taking a municipal sludge and agricultural and forestry waste coordinated treatment project as an example,

[0030] After 50 tons of municipal sludge is dehydrated in the sewage treatment plant, it is transported to the project site for storage and then pumped to the sludge dryer for drying until the moisture content is less than 20%. The dried 12 tons of sludge particles are supplied to farmland for soil improvement. The sludge particles are sent to the pyrolysis device through a quantitative feeding device. The 6 to 7 tons of sludge charcoal produced after pyrolysis enters the farmland for soil improvement. The high-temperature flue gas generated by the combustion of combustible gas produced by pyrolysis enters the steam boiler through the secondary combustion chamber to generate 0.5 to 1 t / h of high-temperature steam. The steam is used as a heat source for sludge drying.

[0031] 40t of agricultural and forestry waste enters the biomass crushing system, then is dried and compressed into about 24t of biomass pellets. These pellets enter the storage bin, and then are sent to the pyrolysis activation device for treatment through a feeding and quantitative feeding device. The generated bioactivated carbon is sold outside, with an output of about 4-5t / h. The high-temperature flue gas generated by the combustion of combustible gas produced by pyrolysis enters the steam boiler through the secondary combustion chamber to generate high-temperature steam, with a steam output of about 2-3t / h, of which about 0.4-0.5t is used for biochar activation reaction, and the rest of the high-temperature steam is used as a heat source for biomass and sludge drying. The tail gas is combined with the sludge tail gas and purified for discharge.

[0032] The products of this system are heat (high-temperature steam) and charcoal (sludge charcoal, biological activated carbon). The heat generated by the system can be consumed internally, and the main product is charcoal. The sludge charcoal is sold to farmers and fruit growers as a soil conditioner. Part of the biomass activated carbon is used in the flue gas treatment system, and the rest is sold as general wood activated carbon.

Claims

1. A coupled pyrolysis treatment system and method for agricultural and forestry waste and municipal sludge, characterized in that: The whole system consists of two main components: municipal sludge treatment and agricultural and forestry waste treatment; The municipal sludge treatment part includes a sludge receiving and storage system, a sludge drying system, a sludge internal heat pyrolysis treatment device, a sludge waste heat utilization system and a flue gas purification system, and each system is connected in sequence; The agricultural and forestry waste treatment part includes a biomass receiving and storing system, a biomass crushing system, a biomass drying system, a biomass homogenizing and granulating system, a biomass internal heat pyrolysis and activation treatment device, a biomass waste heat utilization system and a flue gas purification system, and each system is connected in sequence.

2. The municipal sludge treatment section according to claim 1, characterized in that: The steps include: a. The sludge enters from the sludge receiving and storage system and passes through the sludge drying system to reduce the moisture content to below 15%; b. After drying, the sludge enters the internal heat pyrolysis treatment device for pyrolysis to produce sludge charcoal; c. The high-temperature flue gas generated by the combustion of pyrolysis gas is recycled through the waste heat utilization system to generate steam as the energy source for sludge drying; d. The flue gas is discharged through the flue gas purification system after being purified.

3. The agricultural and forestry waste treatment part according to claim 1 is characterized in that: And includes the following steps; a. Agricultural and forestry waste is crushed into debris with a particle size of less than 5mm in the biomass crushing system; b. Then enter the biomass drying system to reduce the moisture content to below 15%; c. The dried biomass debris enters the uniform granulation system and is made into biomass particles with a particle size of 5 to 8 mm and a length of 3 to 5 cm; d. The dried particles enter the internal heat pyrolysis and activation treatment device for pyrolysis and activation to produce biological activated carbon; e. The high-temperature flue gas generated by the combustion of pyrolysis gas is recycled through the waste heat utilization system to generate steam as the energy source for biomass drying; f. After being purified, the flue gas is discharged through the flue gas purification system.

4. The municipal sludge treatment section according to claim 1, characterized in that: The sludge-based biochar produced by municipal sludge drying and pyrolysis is provided to agricultural and forestry waste production areas for soil improvement and carbon fixation.

5. The agricultural and forestry waste treatment part according to claim 1 is characterized in that: The heat (steam) from the combustion of pyrolysis gas generated by pyrolysis and activation of agricultural and forestry waste is provided to the sludge drying system, and the biochar is used in the flue gas purification system and sold as a charcoal product.

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