CN112520968B

CN112520968B - Sludge carbonization method

Info

Publication number: CN112520968B
Application number: CN202110179739.3A
Authority: CN
Inventors: 谭果强; 梁嘉琪; 曾武; 张小飞
Original assignee: Hunan Jueming Environmental Protection Co ltd
Current assignee: Hunan Jueming Environmental Protection Co ltd
Priority date: 2021-02-08
Filing date: 2021-02-08
Publication date: 2021-06-01
Anticipated expiration: 2041-02-08
Also published as: CN112520968A

Abstract

The application discloses a sludge carbonization method, which comprises the following steps: 1) first dehydration: reducing the water content of the sludge by 10-20% by using hot air; 2) and (3) low-temperature inactivation: secondly dehydrating and inactivating the sludge subjected to the first dehydration at the temperature of 150-300 ℃ to ensure that the water content of the sludge subjected to the second dehydration is less than 10 percent; 3) oxygen-controlled combustion: under the condition of oxygen control, the sludge after the second dehydration is burnt at the temperature lower than 600 ℃; 4) oxygen deficiency stabilization: and (3) delivering the product obtained by combustion into an anoxic link for carbonization and stabilization, cooling to a temperature lower than 40 ℃, and discharging to obtain a final product. The sludge carbonization method provided by the application has the advantages that the investment is small, the sludge burning can be realized, meanwhile, partial heat value is reserved, the sludge carbonization is stable, the additional value is increased, the waste is changed into the valuable, the sludge is thoroughly treated and is pollution-free, the carrying vehicle is used for carrying the sludge, and the working efficiency is improved.

Description

Sludge carbonization method

Technical Field

The application relates to the technical field of sludge treatment, in particular to a sludge carbonization method.

Background

At present, aiming at general solid waste disposal technologies with high calorific value, the general solid waste disposal technologies mainly comprise modes of landfill, incineration, high-temperature dry distillation and the like, most of the solid waste disposal technologies are used for treating a mixture of domestic garbage and municipal sludge, and the disposal technologies are complex in disposal process, large in investment, large in energy consumption and low in disposal efficiency due to complex disposal components. The incineration process is large in investment, the components of the products obtained by treatment are complex, the final treatment difficulty is large, and the final products such as chimney ash and the like still need to be subjected to landfill treatment. The high-temperature dry distillation process is a method utilizing high-temperature anoxic pyrolysis, and because a passive pyrolysis mode of indirect heat conduction is adopted, the heat energy loss is large, so that the energy consumption is high, the heat energy utilization rate is low, and the productivity is low.

With the rapid development of urbanization and national economy, the treatment rate of municipal sewage and industrial sewage is continuously improved, the generation and the quantity of sludge are rapidly increased, and the continuous stressing of national environmental protection policies, the sludge treatment becomes a new specialized industry. And the sludge is treated independently, the pertinence and the specialty are stronger, a treatment process which is suitable for the sludge treatment needs to be developed, and the sludge solid waste treatment is harmless and is recycled.

Disclosure of Invention

In order to solve the above technical problems, a first object of the present invention is to provide a method for carbonizing sludge; the sludge carbonization method provided by the invention fully utilizes the specific physicochemical characteristics of the sludge, namely utilizes the self heat value of the sludge to achieve the purposes of dehydration, inactivation, combustion and carbonization. The technology is matched with brick and tile sintering enterprises, and the advantages are more obvious: the waste heat of the flue gas of the brick and tile kiln is utilized to dehydrate and reburn the sludge. The purposes of energy conservation and emission reduction, higher heat value reservation and the like and obvious economic benefit increase are achieved on the whole. The process method has the advantages of small implementation investment, high productivity, wide product application, high added value, wide social effect and considerable economic effect.

The technical scheme provided by the invention is as follows:

a sludge carbonization method comprises the following steps:

1) first dehydration: reducing the water content of the sludge by 10-20% by using hot air;

2) and (3) low-temperature inactivation: secondly dehydrating and inactivating the sludge subjected to the first dehydration at the temperature of 150-300 ℃ to ensure that the water content of the sludge subjected to the second dehydration is less than 10 percent;

3) oxygen-controlled combustion: under the condition of oxygen control, the sludge after the second dehydration is burnt at the temperature lower than 600 ℃;

4) oxygen deficiency stabilization: and (3) carbonizing and stabilizing a product obtained by combustion under the anoxic condition, cooling to a temperature lower than 40 ℃, and discharging to obtain a final product.

Preferably, in the first dehydration step, the sludge is subjected to first dehydration by using high-temperature flue gas, the flue gas after heat release is extracted, and after water vapor in the flue gas is removed, all or part of the flue gas is sent to an oxygen-controlled combustion area.

Preferably, before the first dewatering, a step of biologically inactivating the sludge with an agent is further included.

Preferably, the step of biologically inactivating is performed in a negative pressure cabin, and air in the negative pressure cabin is pumped out and sent to an oxygen control combustion area.

Preferably, the air extracted by the negative pressure bin is mixed with the flue gas which releases heat and removes water vapor in the first dehydration step in proportion, and then the mixture is sent to an oxygen-controlled combustion area.

Preferably, the high-temperature flue gas comes from sludge oxygen-controlled combustion or from sludge oxygen-controlled combustion and a tile production line; the final product can be used as raw materials or fuels for producing bricks and tiles, ceramic granules, aerated blocks and concrete.

Preferably, in the oxygen deficiency stabilizing step, a product obtained by combustion is stabilized and cooled in a spraying manner.

Preferably, the anoxic stabilization zone is maintained in a positive pressure anoxic environment.

Preferably, the sludge is carried by a carrier vehicle and moves, and the sludge enters a first dehydration region, a low-temperature inactivation region, an oxygen-controlled combustion region and an oxygen-poor stabilization region in sequence to perform first dehydration, second dehydration inactivation region, oxygen-controlled combustion region and oxygen-poor stabilization region.

Preferably, in the step of oxygen-controlled combustion, the loss on ignition of the final product is 35-45%.

The application provides a sludge carbonization method, has following advantage:

firstly, the treatment process is simple to operate, the production flow is compact, and high-degree automatic production and intelligent management are facilitated.

Secondly, the project occupies small area, and saves the land resources.

And thirdly, the energy conservation and emission reduction and the product upgrading can be achieved by cooperating with traditional production enterprises such as bricks and tiles, ceramic particles, aerated blocks, concrete and the like, so that the transformation and upgrading of the traditional industry are realized.

Fourthly, the investment is small, the disposal efficiency is high, the construction investment is 1500 ten thousand yuan, and the corresponding disposal capacity can reach 300-350 tons of daily treatment capacity.

Fifthly, the advantage of high heat value of the sludge is fully utilized, except for the starting stage, partial heat is released through sludge combustion, the heat requirement in the step of oxygen-controlled combustion can be met, sludge combustion is realized, partial heat value is reserved, the sludge is carbonized stably, and the added value is increased.

And sixthly, changing waste into valuable, wherein a final product (such as carbide such as carbon powder) formed after the sludge is carbonized retains a certain heat value, and can be used as a production raw material of building materials such as sintered bricks, ceramsite products, cement and the like.

And seventh, the treatment of the sludge is thorough, pollution is avoided, discharge treatment and product reutilization can be realized, the leakage of harmful gas can be inhibited, and secondary pollution is avoided.

Eighth, use carrier loader delivery mud, increaseed the mud carbonization treatment capacity, improved the work efficiency of mud carbonization greatly.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic process flow diagram of a sludge carbonization method combined with a matched device in the embodiment of the invention;

FIG. 2 is a schematic structural diagram of a device used in a method for carbonizing sludge in an embodiment of the present invention;

FIG. 3 is a schematic plan view of an apparatus for a sludge carbonization method according to an embodiment of the present invention;

reference numerals: 1-a carbonizer; 11-a first dewatering section; 12-a low temperature inactivation stage; 13-oxygen control combustion section; 14-hypoxia stable segment; 2-carrying vehicle; 3-a flue gas treatment system; 4-a condensing mechanism; 5-a flue gas purification device; 6-a cooling system; 7-a storage bin; and 8-finished product warehouse.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or be indirectly disposed on the other element; when an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, refer to an orientation or positional relationship illustrated in the drawings for convenience in describing the present application and to simplify description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "plurality" or "a plurality" means two or more unless specifically limited otherwise.

It should be understood that the structures, ratios, sizes, and the like shown in the drawings are only used for matching the disclosure of the specification, so as to be understood and read by those skilled in the art, and are not used to limit the practical limit conditions of the present application, so that the modifications of the structures, the changes of the ratio relationships, or the adjustment of the sizes, do not have the technical essence, and the modifications, the changes of the ratio relationships, or the adjustment of the sizes, are all within the scope of the technical contents disclosed in the present application without affecting the efficacy and the achievable purpose of the present application.

The embodiments of the present application are written in a progressive manner.

As shown in fig. 1 to fig. 3, an embodiment of the present invention provides a method for carbonizing sludge, including the following steps:

The application provides a sludge carbonization method aiming at the characteristics of sludge, the sludge is subjected to the steps of first dehydration, low-temperature inactivation, oxygen-controlled combustion and oxygen-poor stabilization in sequence, and the sludge is prepared into carbide, so that the resource utilization of the sludge is realized.

In the first dehydration step, part of interstitial water is removed by hot air to reduce the water content of the sludge by 10-20%; secondly, performing secondary dehydration and inactivation on the sludge subjected to the first dehydration, wherein the temperature of the secondary dehydration is 150-300 ℃, the release of molecular cell water of the sludge can be promoted to achieve the effect of rapid dehydration, meanwhile, germs in the sludge can be killed under the temperature condition, the generation of harmful gas is inhibited, and the water content of the sludge subjected to the dehydration is less than 10%; the sludge after the second dehydration enters an oxygen-controlled combustion process, is combusted under the condition of oxygen deficiency, and the highest combustion temperature is controlled not to exceed 600 ℃, so that the combustion and carbonization efficiency of the sludge is conveniently controlled, and the generation of nitrogen oxides is inhibited; and after the combustion reaches the set target, cooling to be lower than 40 ℃, and preventing the carbide from continuing to combust, so that the obtained carbide is stable, and the carbide with the expected combustion degree and ignition loss rate is obtained.

Because the existing sludge is dehydrated by a sewage treatment plant, the contained organic matter is generally more than 50 percent, the water content is also more than 50 percent, the difficulty of compression molding is higher, even if the molding is improved by reducing the water content, the prepared molding blank is easy to seriously collapse when meeting the high temperature of more than 150 ℃, so that the deep dehydration is difficult to carry out, and the treatment on the sludge is influenced; more than 30% of substances with strong viscosity, such as clay and the like, are added into the sludge to achieve the raw material plasticity required by forming, but the addition of the clay wastes resources, and meanwhile, the heat energy consumption is increased, the ash content is increased and the disposal difficulty is increased in the sludge treatment process because the clay does not have a heat value. And the operation of pressing and forming the sludge increases the compactness of the sludge, leads to increase of the difficulty of deep dehydration of the sludge and more heat loss. Therefore, the sludge carbonization method provided by the application abandons the step of pressing and forming the sludge, removes the moisture in the sludge through first dehydration and low-temperature inactivation, then realizes the sludge carbonization under the condition of not adding other components and reduces the resource and heat energy consumption by controlling the oxygen combustion and stabilizing the sludge in an anoxic manner.

Meanwhile, the sludge treatment method provided by the application burns the sludge with the water content of less than 10% obtained after dehydration under the condition of oxygen control, and after the sludge treatment method works stably, the heat generated by the oxygen control combustion section is enough to support the combustion of the newly entered sludge. Compared with the method for treating the sludge by using the high-temperature dry distillation technology, the method needs to use the pyrolysis gas and the external combustion generated in the carbonization process to provide heat for sludge drying and carbonization, and has the problems of large heat loss and low treatment efficiency.

More preferably, the dehydration step can utilize high-temperature flue gas for heat supply, fully utilize the waste heat of the flue gas, and utilize water vapor generated by evaporation of sludge and moisture to adsorb SO in the flue gas₂And H₂S, the temperature of the flue gas can also be reduced. The smoke is extracted after releasing heat, after the water vapor in the smoke is removed, all or part of the smoke is sent to an oxygen-controlled combustion area, and the control of the oxygen content in the combustion is realized by utilizing the characteristic of low oxygen content of the smoke. Preferably, the flue gas after 50% of heat release and water vapor removal is extracted and sent to an oxygen-controlled combustion area, and the flue gas after 50% of heat release and water vapor removal is discharged after the treatment reaches the standard. The percentage of the extracted and discharged flue gas can be flexibly adjusted according to the process requirement.

The first dehydration step is preferably to continuously feed the flue gas and continuously pump the flue gas after heat release, and the first dehydration step can be realized by the position arrangement of the blast pipe and the exhaust pipe.

Preferably, the sludge is also biologically inactivated with an agent prior to the first dewatering. The medicament is a substance commonly used in the art, such as an alkaline substance and the like. More preferably, the step of biological inactivation is carried out in the negative pressure bin, microorganisms in the sludge are continuously propagated, so that odor and harmful gas can be generated in the sludge in the stacking period, the environment pollution is avoided, and the extracted air is sent into an oxygen-controlled combustion area for high-temperature inactivation.

The air extracted from the negative pressure bin is mixed with the flue gas discharged in the first dehydration step, and the proportion is adjusted as required, so that the oxygen content of the gas fed into the oxygen-controlled combustion area can be flexibly controlled.

More preferably, the production line is used together with a brick and tile production line, high-temperature flue gas of the brick and tile production line is utilized, and simultaneously carbide prepared from sludge can be used as a raw material for brick and tile production and mixed in raw materials such as bricks and the like to replace part of coal, so that resource utilization of the sludge and the high-temperature flue gas is realized. In addition, the obtained final product can also be used as raw materials or fuels for producing ceramsite, aerated block and concrete. The high-temperature flue gas introduced into the brick and tile production line and the high-temperature flue gas generated by oxygen-controlled combustion of the sludge dehydrate the sludge, can also increase the heat value of carbides, and improves the availability of the obtained final product.

In order to quickly stabilize the carbide and prevent the carbide from continuously burning, the carbide is preferably cooled by a spraying mode, and meanwhile, the flying dust can be reduced. More preferably, the temperature reduction is performed in an anoxic environment. Because the air is thermally expanded when the carbide dissipates heat, the control of the oxygen content in the environment can be realized by maintaining that the air in the cold area only flows out but not flows in.

Preferably, the sludge carbonization treatment method provided by the application utilizes a carrier loader to carry sludge to move, enters a first dehydration region, a low-temperature inactivation region, an oxygen-controlled combustion region and an oxygen-poor stabilization region in a carbonization device to carry out dehydration, wall-breaking deep dehydration, oxygen-controlled combustion and stabilization, and realizes automatic operation. And discharging after the carbonization of the sludge in the carrier loader is finished, and recycling the empty vehicle.

The application provides a sludge carbonization method, can set up solitary negative pressure storehouse, dewatering device, broken wall device, accuse oxygen burner, securing device and carry out the carbonization of mud according to above step. More preferably, the production is carried out by using a matched sludge carbonizing device. The matched sludge carbonizing device comprises the following concrete steps:

a sludge carbonizing apparatus comprising:

the carbonizer 1, the carbonizer 1 includes the first dehydration section 11, the low temperature inactivation section 12, the oxygen control combustion section 13, the oxygen deficiency stabilization section 14 sequentially;

the carrier loader 2 is used for carrying sludge to move and enter the carbonizer 1 for treatment;

the flue gas treatment system 3 comprises a first flue gas treatment pipe and a second flue gas treatment pipe, the first dehydration section 11 is also communicated with the condensation mechanism 4, and the first flue gas treatment pipe is communicated with the condensation mechanism 4 and the oxygen-controlled combustion section 13 and is used for returning part or all of condensed flue gas to the oxygen-controlled combustion section 13; the condensing mechanism 4 is also communicated with a flue gas purification device 5; one end of the second flue gas treatment pipe is communicated with the first dehydration section 11, and the other end of the second flue gas treatment pipe is communicated with a high-temperature flue gas outlet of a tile production line;

the cooling system 6 is also arranged, the cooling system 6 comprises a water delivery pipe and a spray pipe, one end of the water delivery pipe is connected with a water source, and the other end of the water delivery pipe is connected with the spray pipe and used for supplying cold water to the anoxic stabilizing section 14;

the sludge storage bin 7 is also arranged for storing sludge, and the carrier vehicle 2 loads the sludge in the sludge storage bin 7 and carries the sludge to enter the carbonizer 1 for treatment; the storage bin 7 is provided with a storage bin air draft system which is communicated with the oxygen-controlled combustion section 13 through a pipeline and sends the pumped gas into the oxygen-controlled combustion section 13;

a finished product bin 8 for storing finished products after the sludge carbonization is also arranged, the carrier loader 2 unloads materials in the finished product bin 8, and the finished product bin 8 is also provided with a dust collecting mechanism;

and a carrier loader circulating line is further arranged, the carrier loader 2 moves to the storage bin 7 through the carrier loader circulating line after being unloaded from the finished product bin 8, is loaded with sludge, and then enters the carbonizer 1 for carbonization treatment.

The matched sludge carbonizing device is shown in figures 2-3.

Example 1

A sludge carbonization method comprises the following steps:

biologically inactivating the sludge in the negative pressure bin by using a medicament, pumping out air in the negative pressure bin, and sending the air into an oxygen-controlled combustion area;

first dehydration: performing first dehydration on the sludge by utilizing a sludge oxygen-controlled combustion area and high-temperature flue gas of a tile production line, and reducing the water content of the sludge by 10-20%; extracting the flue gas after heat release, removing water vapor in the flue gas, sending part of the flue gas into an oxygen-controlled combustion area, and treating the rest flue gas to reach the standard and discharge;

and (3) low-temperature inactivation: secondly dehydrating and inactivating the dehydrated sludge at the temperature of 150-300 ℃ to ensure that the water content of the sludge after the second dehydration is less than 10 percent;

oxygen-controlled combustion: under the condition of oxygen control, the sludge after the second dehydration is burnt at the temperature lower than 600 ℃;

oxygen deficiency stabilization: and (3) cooling the carbide obtained by combustion to be lower than 40 ℃ in a water spraying manner under a positive pressure oxygen-deficient environment, and discharging to obtain a final product.

The final product is used as raw material for brick and tile production.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The sludge carbonization method is characterized by comprising the following steps:

4) oxygen deficiency stabilization: carbonizing and stabilizing a product obtained by combustion under an anoxic condition, cooling to a temperature lower than 40 ℃, and discharging to obtain a final product;

the sludge carbonization treatment method comprises the steps of carrying sludge to move by using a carrier vehicle, and sequentially entering a first dehydration region, a low-temperature inactivation region, an oxygen-controlled combustion region and an oxygen-deficient stabilization region in a carbonization device to carry out first dehydration, second dehydration inactivation, oxygen-controlled combustion and oxygen-deficient stabilization; discharging after the sludge in the carrier loader is carbonized, and recycling empty vehicles;

the sludge carbonizing device comprises a carbonizer (1), wherein the carbonizer (1) sequentially comprises a first dehydrating section (11), a low-temperature inactivating section (12), an oxygen-controlled combustion section (13), an oxygen-deficiency stabilizing section (14) and a flue gas treatment system (3), the flue gas treatment system (3) comprises a first flue gas treatment pipe and a second flue gas treatment pipe, the first dehydrating section (11) is further communicated with a condensing mechanism (4), and the first flue gas treatment pipe is communicated with the condensing mechanism (4) and the oxygen-controlled combustion section (13) and is used for returning part or all of condensed flue gas to the oxygen-controlled combustion section (13); one end of the second flue gas treatment pipe is communicated with the first dehydration section (11), and the other end of the second flue gas treatment pipe is communicated with a high-temperature flue gas outlet of a tile production line;

the anoxic stabilization section (14) is in a positive pressure anoxic environment;

in the first dehydration step, performing first dehydration on the sludge by using high-temperature flue gas, extracting the flue gas after heat release, and after removing water vapor in the flue gas, sending all or part of the flue gas into an oxygen-controlled combustion area; the high-temperature flue gas comes from sludge oxygen-controlled combustion or from sludge oxygen-controlled combustion and a brick and tile production line;

before the first dehydration, the method further comprises a step of biologically inactivating the sludge by using a medicament, wherein the step of biologically inactivating is carried out in the negative pressure bin, air in the negative pressure bin is pumped out, and the air pumped out by the negative pressure bin is mixed with the flue gas which is subjected to heat release in the first dehydration step and water vapor removal in proportion and then is sent to an oxygen control combustion area.

2. The method of sludge carbonization as claimed in claim 1, wherein the final product can be used as raw material or fuel for brick and tile, ceramsite, aerated block, concrete production.

3. The sludge carbonization method according to claim 1, wherein in the anoxic stabilization step, the products obtained by combustion are stabilized and cooled by spraying.

4. The sludge carbonization method as claimed in claim 3, wherein the anoxic robust region is maintained in a positive pressure anoxic environment.

5. The method for carbonizing sludge according to any one of claims 1 and 3 to 4, wherein in the step of oxygen-controlled combustion, the loss on ignition of the final product is 35 to 45%.