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CN-121990745-A - Sludge low-temperature oxidation treatment system and method

CN121990745ACN 121990745 ACN121990745 ACN 121990745ACN-121990745-A

Abstract

The invention discloses a sludge low-temperature oxidation treatment system and a method thereof, the system comprises a pretreatment unit, a feeding lifting mechanism, a low-temperature oxidation furnace, a flue gas purification unit and an automatic control unit. The low-temperature oxidation furnace is divided into a feeding area, a low-temperature oxidation area and a wind distribution slag discharging area from top to bottom, the wind distribution plate is provided with uniform array air outlets, the temperature of the low-temperature oxidation area is controlled to be 420-480 ℃, and the generation of dioxin is inhibited from the source. The method comprises the steps of material mixing, continuous feed oxidation, temperature closed-loop regulation and control, flue gas purification and ash treatment, the method can stably treat municipal sludge with high water content, has low energy consumption and low dioxin generation, meets the flue gas emission standard, and the ash can be recycled and is suitable for harmless treatment of large-scale municipal sludge.

Inventors

  • MAO KEFENG
  • Zeng Yushu
  • SHI MINGXUAN
  • Mao Shangyuan
  • SHEN SHANSHAN

Assignees

  • 象山德曼机械有限公司

Dates

Publication Date
20260508
Application Date
20260409

Claims (10)

  1. 1. The sludge low-temperature oxidation treatment system is characterized by comprising a pretreatment unit, a feeding lifting mechanism, a low-temperature oxidation furnace (4), a flue gas purification unit and an automatic control unit (9) which are connected in sequence; the pretreatment unit comprises a sludge storage tank (1), a biomass storage tank (2) and a mixer (3), wherein the mixer (3) is used for mixing sludge, biomass and quartz sand to form a loose and breathable mixed material, the inner space of the low-temperature oxidation furnace (4) is divided into a feeding area (41), a low-temperature oxidation area (42) and an air distribution deslagging area (43) which are mutually communicated from top to bottom, a heat-resistant lining is arranged on the furnace wall of the low-temperature oxidation area (42), the air distribution deslagging area (43) comprises an air distribution plate (431), a plurality of air outlets (432) are formed in the air distribution plate (431), an air chamber (44) located below the air distribution plate (431) and an air supply device communicated with the air chamber (44), the flue gas purification unit is connected with a flue gas outlet of the low-temperature oxidation furnace (4), and the automatic control unit (9) is in signal connection with a monitoring instrument and an executing mechanism in the system.
  2. 2. The sludge low-temperature oxidation treatment system according to claim 1, wherein a plurality of temperature monitoring points are arranged on the furnace wall of the low-temperature oxidation zone (42) along the height direction of the furnace wall, and the air outlets (432) are uniformly distributed on the air distribution plate (431) in an array mode.
  3. 3. The sludge low-temperature oxidation treatment system according to claim 1, wherein the pretreatment unit further comprises a drier (5), a feed inlet of the drier (5) is connected with the sludge storage tank (1), a discharge outlet of the drier is connected with the mixer (3), and an outlet of the sludge storage tank (1) is configured to be selectively communicated with the feed inlet of the mixer (3) or the drier (5) through a pipeline.
  4. 4. The sludge low-temperature oxidation treatment system according to claim 1, wherein the flue gas purification unit comprises a waste heat recovery device, a cyclone separator (6), a dust remover (7), a desulfurization device (8) and a denitration device which are sequentially arranged along the flue gas flowing direction, a solid outlet of the cyclone separator (6) is connected with a reburning furnace (12) through a pipeline, and the reburning furnace (12) is connected to a flue gas pipeline of the low-temperature oxidation furnace (4).
  5. 5. The sludge low-temperature oxidation treatment system according to claim 1, wherein the automatic control unit (9) comprises a temperature sensor (91) arranged in the low-temperature oxidation zone (42), a flue gas automatic monitoring system (92) arranged at a discharge port of the flue gas purification unit, and a controller (93), wherein the controller (93) is in signal connection with the temperature sensor (91), the flue gas automatic monitoring system (92) and the air supply device, and is configured to adjust the air supply quantity of the air supply device according to the signal of the temperature sensor (91).
  6. 6. The sludge cryogenic oxidation treatment system of claim 5 wherein the controller (93) controls the temperature of the cryogenic oxidation zone (42) to be in the range of 420 ℃ to 480 ℃.
  7. 7. A sludge low-temperature oxidation treatment system according to claim 1, wherein the air supply device comprises a fluidization fan (10) and a preheating furnace (11), and the preheating furnace (11) is used for preheating combustion air provided by the fluidization fan (10) by utilizing system flue gas waste heat.
  8. 8. A sludge cryogenic oxidation treatment system according to claim 1, further comprising screening means (16) for screening ash discharged from the wind distribution slag discharge zone (43), the separated quartz sand being returned to the mixer (3).
  9. 9. A method of low temperature oxidation treatment of sludge using the system of any one of claims 1-8, comprising the steps of: S1, preparing materials, namely mixing municipal dewatered sludge with the water content of 60-80% with biomass and quartz sand in proportion to obtain loose and breathable mixed materials; S2, continuously feeding and reacting, namely continuously feeding the mixed material into a low-temperature oxidation furnace (4), enabling the material to move from top to bottom in the furnace, sequentially passing through a feeding region (41), a low-temperature oxidation region (42) and a wind distribution slag discharging region (43), and enabling the material to undergo low-temperature oxidation reaction in a temperature range of 420-480 ℃ in the low-temperature oxidation region (42) through preheated air supplied by a wind distribution plate (431) and a wind chamber (44); S3, process control, namely monitoring the temperature through a temperature sensor (91) arranged in the low-temperature oxidation zone (42), and automatically adjusting the air supply quantity according to the temperature, so that the temperature of the low-temperature oxidation zone (42) is stably maintained in a preset temperature range; S4, product treatment, namely discharging ash generated by the reaction from the furnace bottom, and discharging the flue gas generated by the reaction after waste heat recovery, dust removal, desulfurization and denitrification purification to reach the standard.
  10. 10. The method for low-temperature oxidation treatment of sludge according to claim 9, wherein in the step S1, the biomass is wood chips or rice hulls, the mixing weight ratio of the biomass to the sludge is 6:4-7:3 on a dry basis, the particle size of quartz sand is 1-3 mm, the sludge content is 60-80%, the biomass content is 15-30% and the quartz sand content is 5-15% based on the total weight of the mixed materials, and in the step S3, the preset temperature range is 420-480 ℃.

Description

Sludge low-temperature oxidation treatment system and method Technical Field The invention relates to the technical field of solid waste treatment, in particular to a sludge low-temperature oxidation treatment system and a method thereof. Background Currently, the main disposal modes of sludge, such as landfill, composting and incineration, have limitations. Landfill occupies a large amount of land resources and has the risk of long-term environmental pollution, and has long composting period and limited stabilizing effect on pollutants such as heavy metals. While the traditional incineration technology can realize sludge reduction, two inherent defects are that firstly, the sludge needs to be subjected to deep dehydration (the water content is required to be lower than 50 percent generally), the energy consumption in the pretreatment process is extremely high, and secondly, in order to ensure complete decomposition of pollutants, the incinerator needs to operate at a high temperature of above 850 ℃, so that the energy consumption and the operation cost of the system are high, and the high-temperature environment is easy to promote the generation of extremely toxic pollutants such as dioxin, so that the difficulty and the cost of subsequent flue gas purification are greatly increased. In recent years, low-temperature oxidation technology has been attracting attention because of its potential for treating low-heating value organic waste at a relatively low temperature (400-550 ℃), and the technology has the advantages of low energy consumption, low smoke amount, low risk of dioxin production, and the like in theory. However, the existing low-temperature oxidation technology still has obvious bottlenecks when municipal sludge with high water content is treated, namely, firstly, the heat value of the sludge with high water content is low, stable self-sustaining reaction is difficult to maintain, secondly, the sludge is easy to soften, adhere and harden due to heating, the air permeability of a material layer is poor, oxidation reaction is uneven, furthermore, the control precision of reaction temperature is insufficient, local overtemperature is easy to occur, the generation risk of dioxin still exists, and finally, a full-flow automatic integrated system from material pretreatment, accurate temperature control reaction and deep purification of flue gas to ash recycling is lacked, so that the requirement of industrialized continuous stable operation is difficult to meet. Due to the lack of an effective hardening prevention means, the optimal low-temperature oxidation temperature region of 400-500 ℃ is generally subjected to a aversion to a difficult emotion in the industry, so that the related technology is difficult to industrially land. Disclosure of Invention The invention aims to provide a sludge low-temperature oxidation treatment system and a method thereof, which construct a totally-enclosed continuous treatment process from sludge receiving, conditioning, conveying, low-temperature oxidation reaction to ash discharge and flue gas purification, ensure that the sludge forms a stable and uniform low-temperature oxidation reaction zone in a furnace through a three-section structure of a furnace body and a unique uniform air distribution design, fundamentally prevent materials from hardening, realize accurate closed-loop control on the temperature of a reaction core, strictly stabilize the temperature below 500 ℃, prevent dioxin from generating from a thermodynamic source, integrate a waste heat recovery and high-efficiency multi-stage flue gas purification device, improve the overall energy efficiency of the system and ensure ultralow emission of tail gas, and finally realize safe, stable and high-efficiency operation of the system through high-automation control. The technical aim of the invention is realized by the following technical scheme: A sludge low-temperature oxidation treatment system comprises a pretreatment unit, a feeding lifting mechanism, a low-temperature oxidation furnace, a flue gas purification unit and an automatic control unit which are connected in sequence; The pretreatment unit comprises a sludge storage tank, a biomass storage tank and a mixer, wherein the mixer is used for mixing sludge, biomass and quartz sand to form a loose and breathable mixed material, the inner space of the low-temperature oxidation furnace is divided into a feeding area, a low-temperature oxidation area and an air distribution deslagging area which are mutually communicated from top to bottom, a heat-resistant lining is arranged on the furnace wall of the low-temperature oxidation area, the air distribution deslagging area comprises an air distribution plate, a plurality of air outlets arranged on the air distribution plate, an air chamber below the air distribution plate and an air supply device communicated with the air chamber, the flue gas purification unit is connected with a flue gas outlet of the lo