Comprehensive treatment method for preparing bricks by synergy of high-water-content general solid waste sludge

Abstract

The invention discloses a comprehensive treatment method for preparing bricks through synergy of high-water-content general solid waste sludge. The comprehensive treatment method comprises the steps of pyrohydrolysis pretreatment and anaerobic digestion deep dehydration, rotary kiln coking deep dehydration and stabilization, multi-source solid waste synergy mixing, brick making and the like. According to the method, deep dehydration, stabilization and harmlessness of the high-water-content sludge are achieved through the combined process of'thermal hydrolysis, anaerobic digestion and rotary kiln coking ', meanwhile, the sludge residues subjected to deep treatment and multiple solid wastes such as shale, construction waste and coal gangue are synergistically used as brick making raw materials, resource utilization of the multiple solid wastes is achieved, and the method is suitable for large-scale production. The method has the advantages of high deep dehydration efficiency, thorough sludge stabilization, energy recovery and utilization, solid waste synergetic recycling, remarkable environmental benefits, improvement of economic benefits and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste treatment, and in particular to a comprehensive treatment method for high-water-content general solid waste sludge in synergistic brick making. Background Art

[0002] In recent years, with the acceleration of urbanization and the continuous increase in sewage treatment volume in my country, sludge production has also increased. Sludge has a complex composition, containing large amounts of harmful substances such as organic matter, heavy metals, and pathogens. It also has high moisture content and unstable properties. This makes sludge reduction, stabilization, and harmless treatment and disposal a huge challenge.

[0003] Currently, traditional sludge treatment and disposal methods primarily include landfilling, incineration, and composting. However, these methods have numerous drawbacks. For example, landfilling not only consumes significant land resources but can also lead to soil and groundwater pollution. While incineration can reduce sludge volume and render it harmless, it is energy-intensive and requires significant investment, and can produce hazardous substances such as dioxins. Composting, on the other hand, has a long treatment cycle, requires significant land, and produces unstable product quality, making it difficult to recycle the waste.

[0004] Furthermore, with the country's increasing emphasis on environmental protection and the proposed "dual carbon" goals, traditional sludge treatment and disposal methods are no longer able to meet the new environmental protection requirements and resource utilization needs. Therefore, this invention proposes a highly efficient, economical, and environmentally friendly comprehensive sludge disposal method that achieves deep dehydration, stabilization, harmlessness, and resource utilization of sludge. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a comprehensive treatment method for general solid waste sludge with high moisture content for collaborative brick making, which has a reasonable structural design and is easy to promote.

[0006] A comprehensive treatment method for high-water content general solid waste sludge in synergistic brick making comprises the following steps:

[0007] S1. Thermal hydrolysis pretreatment and anaerobic digestion deep dehydration

[0008] General solid waste sludge with a moisture content higher than 80% is fed into a thermal hydrolysis reactor and treated at a specific temperature and pressure for a period of time to break the sludge cell walls, release bound water, and improve the sludge's biodegradability and dehydration performance. The thermally hydrolyzed sludge is then fed into an anaerobic digester and subjected to anaerobic digestion at an appropriate temperature and residence time to reduce the sludge moisture content to below 60%, while achieving degradation and stabilization of organic matter.

[0009] S2. Deep dehydration and stabilization of rotary kiln coking

[0010] The digested sludge obtained in step S1 with a moisture content of less than 60% is fed into a rotary kiln. Under anoxic or micro-oxic conditions, the temperature in the kiln is controlled within the coking temperature range for coking treatment, so that the moisture content of the sludge is further reduced to below 30%, achieving stabilization and harmlessness, and obtaining coking sludge residue.

[0011] S3. Coordinated mixing of multi-source solid waste and brick making

[0012] The coking sludge residue with a moisture content of less than 30% obtained in step S2 is fully and evenly mixed with other solid waste raw materials such as shale powder, crushed and screened construction waste, crushed and screened coal gangue powder, etc. in a mixing device in a predetermined proportion, and an appropriate amount of binder and water are added to adjust the moisture content of the mixture to a level suitable for brick making. The evenly mixed materials are then fed into a brick making machine to be formed into brick blanks. After the brick blanks are dried, they are fed into a tunnel kiln for sintering and finally fired into building bricks.

[0013] Preferably, the treatment temperature of the thermal hydrolysis reactor is 150-180° C., the pressure is the corresponding saturated steam pressure, and the treatment time is 30-60 minutes.

[0014] Preferably, the temperature of the anaerobic digester is a medium temperature of 35-38°C or a high temperature of 50-55°C, and the residence time is 15-25 days.

[0015] Preferably, the coking temperature range of the rotary kiln is 300-600°C.

[0016] Preferably, the coking sludge residue accounts for 10%-40% of the total dry basis mass.

[0017] Preferably, the moisture content of the mixture is adjusted to 12%-18%.

[0018] Preferably, the sintering temperature of the tunnel kiln is 900-1100°C.

[0019] The beneficial effects of the present invention are:

[0020] 1. High efficiency of deep dehydration: The first stage of deep dehydration (>80%-><60%) is achieved through the combination of "thermal hydrolysis + anaerobic digestion", and the second stage of deep dehydration (<60%-><30%) is achieved through "rotary kiln coking", which solves the bottleneck problem of high-moisture sludge dehydration and significantly reduces the volume.

[0021] 2. Sludge stabilization is thorough: anaerobic digestion degrades easily degradable organic matter, while the coking process treats difficult-to-degrade organic matter and kills pathogens. The final product is stable and harmless.

[0022] 3. Energy recovery and utilization: The biogas produced by anaerobic digestion can be recycled; the residual carbon in the coking sludge residue can provide part of the heat energy during the sintering process, reducing the energy consumption of brick making.

[0023] 4. Collaborative resource utilization of solid waste: Innovatively combine deeply treated sludge residue with shale, construction waste, coal gangue and other solid wastes as raw materials for brick making, achieving the "full utilization" and efficient resource utilization of various solid wastes.

[0024] 5. Significant environmental benefits: It avoids the land occupation and pollution risks of sludge landfill, reduces the energy consumption and emissions of incineration, and reduces the environmental pressure of other solid waste disposal, with an overall significant carbon emission reduction effect.

[0025] 6. Improved economic benefits: The income from resource-based products (bricks, biogas) can significantly reduce the comprehensive disposal costs of high-moisture sludge and mixed solid waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 The present invention is a flow chart of a comprehensive disposal method for high-water-content general solid waste sludge in collaborative brick making. DETAILED DESCRIPTION

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0029] A comprehensive treatment method for high-water content general solid waste sludge in synergistic brick making comprises the following steps:

[0030] S1: Thermal hydrolysis pretreatment and anaerobic digestion deep dehydration

[0031] General solid waste sludge with a moisture content above 80% is fed into a thermal hydrolysis reactor. It is treated at a specific temperature (preferably 150-180°C) and pressure (preferably corresponding to saturated steam pressure) for a period of time (preferably 30-60 minutes) to break down the sludge cell walls, release bound water, and significantly improve the sludge's biodegradability and dewatering properties.

[0032] After thermal hydrolysis, the sludge enters the anaerobic digester, where it undergoes anaerobic digestion at an appropriate temperature (35-38°C for medium temperature or 50-55°C for high temperature) and a residence time (preferably 15-25 days). The anaerobic digestion process not only produces biogas (recoverable energy), but more importantly, further decomposes organic matter and releases water through the action of microorganisms.

[0033] After this step, the moisture content of the sludge is significantly reduced to below 60% (preferably to the range of 50%-58%), while the degradation and stabilization of organic matter are achieved.

[0034] S2: Deep dehydration and stabilization of rotary kiln coking

[0035] The digested sludge obtained in step S1 with a moisture content of less than 60% is fed into a rotary kiln for coking under anoxic or micro-oxic conditions, with the temperature in the kiln controlled within the coking temperature range (preferably 300-600° C.).

[0036] The water in the sludge is rapidly evaporated and removed, while some organic matter undergoes pyrolysis and carbonization. This step further reduces the sludge moisture content to below 30% (preferably to a range of 15%-25%), significantly reducing the volume and achieving more thorough stabilization and harmlessness (killing pathogens and degrading difficult-to-degrade organic matter).

[0037] The product is coking sludge residue, which has a certain calorific value.

[0038] S3: Co-mixing of multi-source solid waste and brick making

[0039] The coking sludge residue with a moisture content of less than 30% obtained in step S2 is fully and evenly mixed with other solid waste raw materials such as shale powder, crushed and screened construction waste, crushed and screened coal gangue powder, etc. in a mixing device according to a predetermined proportion (preferably the coking sludge residue accounts for 10%-40% of the total dry basis mass).

[0040] Add appropriate amount of binder and water as needed to adjust the moisture content of the mixture to a level suitable for brick making (usually 12%-18%).

[0041] The evenly mixed materials are fed into a brick making machine (such as a vacuum extruder or brick press) to be formed into bricks.

[0042] After drying (natural or artificial), the bricks are sent to the tunnel kiln for sintering (sintering temperature 900-1100℃). During the sintering process, the residual carbon in the coking sludge residue can be used as part of the fuel. Its ash is melted and combined with the silicon and aluminum components in shale, construction waste, and coal gangue to form a stable silicate structure. Finally, it is fired into building bricks that meet national standards.

[0043] Example 1

[0044] Thermal hydrolysis pretreatment and anaerobic digestion deep dehydration: 10 tons of general solid waste sludge with an 85% moisture content was fed into a 15-cubic-meter thermal hydrolysis reactor. The reactor temperature was raised to 160°C and the pressure reached the corresponding saturated vapor pressure, maintaining these conditions for 45 minutes. The hydrolyzed sludge then entered a 50-cubic-meter anaerobic digester, maintained at a controlled temperature of 37°C, and held for 20 days. Testing showed that the sludge moisture content had dropped to 55% after anaerobic digestion.

[0045] Rotary Kiln Coking Deep Dehydration and Stabilization: The digested sludge from step 1 is fed into a rotary kiln. A micro-aerobic environment is maintained in the rotary kiln, with the temperature controlled at 650°C for two hours. Testing indicates that the moisture content of the sludge residue after coking has dropped to 20%.

[0046] Synergistic mixing and brick making of multi-source solid waste: 2 tons of coking sludge residue from step 2 are mixed with 3 tons of shale powder, 4 tons of crushed and screened construction waste, and 1 ton of crushed and screened coal gangue powder in a forced mixer. An appropriate amount of clay is added as a binder, and water is added to adjust the moisture content of the mixture to 15%. The mixture is formed into bricks using a vacuum extruder. After natural drying, the bricks are sintered in a tunnel kiln at 1000°C. The resulting building bricks meet national standards for all performance indicators after testing.

[0047] Example 2

[0048] Thermal hydrolysis pretreatment and anaerobic digestion deep dehydration: 15 tons of general solid waste sludge with an 83% moisture content was transferred to a thermal hydrolysis reactor and treated at 150°C and saturated steam pressure for 60 minutes. The sludge was then introduced into an anaerobic digester and held at 52°C for 18 days. Measurements showed that the sludge moisture content was reduced to 52%.

[0049] Rotary Kiln Coking Deep Dehydration and Stabilization: The digested sludge from step 1 is fed into a rotary kiln and treated for 1.5 hours under anoxic conditions, maintaining the kiln temperature at 550°C. The resulting coking sludge residue has a moisture content of 18%.

[0050] Coordinated mixing and brick making of multi-source solid waste: Weigh 3 tons of coking sludge residue from step 2 and mix it with 2 tons of shale powder, 5 tons of construction waste, and 0.5 tons of coal gangue powder. An appropriate amount of slag binder is added, and the moisture content is adjusted to 14%. A brick press is used to form the mixture into bricks. After artificial drying, the bricks are sintered in a tunnel kiln at 950°C. The resulting bricks meet construction quality standards.

[0051] Example 3

[0052] Thermal hydrolysis pretreatment and anaerobic digestion deep dehydration: 8 tons of general solid waste sludge with an 88% moisture content was fed into the thermal hydrolysis reactor and treated at 180°C and saturated steam pressure for 30 minutes. The sludge was then introduced into the anaerobic digester, maintained at a medium temperature of 35°C, for 25 days. After treatment, the sludge moisture content dropped to 58%.

[0053] Rotary Kiln Coking Deep Dehydration and Stabilization: The digested sludge from step 1 is fed into a rotary kiln and treated for 2.5 hours at a temperature of 800°C in a micro-aerobic environment. The moisture content of the coking sludge residue is reduced to 15%.

[0054] Coordinated mixing and brick making of multi-source solid waste: 1 ton of coking sludge residue from step 2 is thoroughly mixed with 4 tons of shale powder, 3 tons of construction waste, and 2 tons of coal gangue powder. An appropriate amount of binder is added, and the moisture content is adjusted to 16%. Bricks are formed using a vacuum extruder, dried, and sintered in a tunnel kiln at 1050°C. The resulting building bricks meet quality requirements.

[0055] The present invention achieves deep dehydration, stabilization and harmlessness of general solid waste sludge with high water content through a series of specific treatment steps, and synergizes it with other solid wastes such as shale, construction waste, coal gangue to prepare building bricks, achieving the goals of "reduction, stabilization, harmlessness and resource utilization".

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A comprehensive treatment method for high-water content general solid waste sludge in conjunction with brick making, characterized in that , including the following steps: S1. Thermal hydrolysis pretreatment and anaerobic digestion deep dehydration General solid waste sludge with a moisture content higher than 80% is fed into a thermal hydrolysis reactor and treated at a specific temperature and pressure for a period of time to break the sludge cell walls, release bound water, and improve the sludge's biodegradability and dehydration performance. The thermally hydrolyzed sludge is then fed into an anaerobic digester and subjected to anaerobic digestion at an appropriate temperature and residence time to reduce the sludge moisture content to below 60%, while achieving degradation and stabilization of organic matter. S2. Deep dehydration and stabilization of rotary kiln coking The digested sludge obtained in step S1 with a moisture content of less than 60% is fed into a rotary kiln. Under anoxic or micro-oxic conditions, the temperature in the kiln is controlled within the coking temperature range for coking treatment, so that the moisture content of the sludge is further reduced to below 30%, achieving stabilization and harmlessness, and obtaining coking sludge residue. S3. Coordinated mixing of multi-source solid waste and brick making The coking sludge residue with a moisture content of less than 30% obtained in step S2 is fully and evenly mixed with other solid waste raw materials such as shale powder, crushed and screened construction waste, crushed and screened coal gangue powder, etc. in a mixing device in a predetermined proportion, and an appropriate amount of binder and water are added to adjust the moisture content of the mixture to a level suitable for brick making. The evenly mixed materials are then fed into a brick making machine to be formed into brick blanks. After the brick blanks are dried, they are fed into a tunnel kiln for sintering and finally fired into building bricks.

2. The comprehensive treatment method for high-water content general solid waste sludge in brick making according to claim 1 is characterized by: The treatment temperature of the thermal hydrolysis reactor is 150-180° C., the pressure is the corresponding saturated steam pressure, and the treatment time is 30-60 minutes.

3. The comprehensive treatment method for high-water content general solid waste sludge in brick making according to claim 1 is characterized by: The temperature of the anaerobic digestion tank is a medium temperature of 35-38° C. or a high temperature of 50-55° C., and the residence time is 15-25 days.

4. The comprehensive treatment method for high-water content general solid waste sludge in brick making according to claim 1 is characterized by: The coking temperature range of the rotary kiln is 300-600°C.

5. The comprehensive treatment method for high-water content general solid waste sludge in brick making according to claim 1 is characterized by: The coking sludge residue accounts for 10% to 40% of the total dry basis mass.

6. The comprehensive treatment method for high-water content general solid waste sludge in brick making according to claim 1 is characterized by: The moisture content of the mixture is adjusted to 12%-18%.

7. The comprehensive treatment method for high-water content general solid waste sludge in brick making according to claim 1 is characterized by: The sintering temperature of the tunnel kiln is 900-1100°C.

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