CN214400192U - Municipal sludge pyrolysis treatment system - Google Patents

Abstract

The utility model provides a municipal administration sludge pyrolysis treatment system, mud are after the biochemical sludge thermal oxidation treatment of medium temperature middling pressure is as dehydration decrement preliminary treatment, send into the interior pyrolysis carbonization of vertical pyrolysis apparatus of whole airtight pressure-fired, anoxybiotic burning at last. Apart from the sludge-based biochar product output system, the pyrolysis gas of the product enters spray for separation and purification, and the purified combustible gas is sent into a combustor for combustion as a recycling heat source; carrying out secondary pyrolysis on the purified and separated heavy components; the generated non-condensable carbonized tail gas is subjected to deodorization treatment and then is discharged after reaching the standard. The invention changes the property of the sludge through chemical reaction, is the final treatment process of the sludge, has the advantages of simple production process, stable state of the product and no secondary pollution, realizes the reduction, stabilization, harmlessness and reclamation of the sludge treatment, and conforms to the four-way principle of the sludge treatment.

Description

Municipal sludge pyrolysis treatment system

Technical Field

The utility model belongs to the technical field of solid waste handles, especially, relate to a municipal sludge pyrolysis treatment system.

Background

With the development of cities and towns in recent years, the national sewage treatment amount and treatment rate are increased, and the amount of sludge waste generated is increased. In China, the treatment amount of the sludge meeting the safety treatment regulations is not more than 10 percent, which means that more than 3500 million tons of sludge waits for safe treatment and treatment every year on the market.

The complexity of the composition and properties of the sludge determines the difficulty of the disposal of the sludge, and poses a serious challenge to the technology. Although various technologies emerge at home and abroad in recent years, the four basic principles of reduction, stabilization, harmlessness and recycling are used for measurement, and at present, various different treatment technologies are often considered to be different from each other, so that a reasonable technical and economic target is difficult to achieve.

The key goal of sludge treatment disposal is volume reduction, which is to reduce the water content and reduce the sludge volume to the maximum extent in view of the characteristics of the sludge. The choice and degree of implementation of the abatement technology path determines the cost to be paid for the complete treatment disposal of the sludge.

The sludge is treated by different treatment processes at different water contents, and when the water content of the sludge is reduced from more than 90% to 60%, a sludge dewatering process is adopted; and when the concentration is 60 to 10 percent, a drying process is adopted. With respect to the conventional process, sludge dewatering is mainly achieved by mechanical filter pressing; the sludge drying is realized by heat energy no matter what energy source. The drying link is the main link of energy consumption of the sludge treatment system, and is the point of energy conservation and consumption reduction of the sludge treatment system, and the dehydration is the premise of low-cost drying.

At present, sludge dewatering and drying processes commonly adopted at home and abroad mainly have two aspects, namely conditioning sludge by chemical, physical and biological methods, reducing sludge specific resistance and improving sludge dewatering effect, and stripping liquid water contained in the sludge in an evaporation mode by supplying heat. The former representative process technology comprises a belt type dehydrator, a centrifugal dehydrator, a lime conditioning high-pressure plate-and-frame filter press and an integrated process of sludge pyrohydrolysis, sludge anaerobic digestion and plate-and-frame dehydration, and the technologies generally have the problems of high sludge moisture content and poor volume reduction effect after dehydration; the latter includes processes of heating by using a gas boiler, converting electric energy of a heat pump unit and the like, and the processes have the problems of high energy consumption and high operation cost. And the traditional municipal sludge treatment method is easy to cause secondary pollution.

Disclosure of Invention

In order to solve the technical problem, the utility model provides a municipal sludge pyrolysis treatment system. The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed embodiments. This summary is not an extensive overview and is intended to neither identify key/critical elements nor delineate the scope of such embodiments. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

The utility model adopts the following technical scheme:

provided is a municipal sludge pyrolysis treatment system comprising:

the medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem is used for carrying out catalytic oxidation dehydration decrement pretreatment on the slurry to generate a biochar cake;

and the pyrolysis carbonization subsystem is used for carrying out pyrolysis carbonization treatment on the biochar cake to output sludge-based biochar.

In some alternative embodiments, the medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem comprises: the heat exchange device, the gas-liquid separator and the catalytic oxidation reaction kettle; and the slurry is subjected to heat exchange and temperature rise by the heat exchange device and then is conveyed to the catalytic oxidation reaction kettle for catalytic oxidation, the high-temperature oxidation filtrate after catalytic oxidation is conveyed to the gas-liquid separator, and the high-temperature carbonization slurry separated by the gas-liquid separator flows back to the heat exchange device for preheating the slurry.

In some optional embodiments, the heat exchange device comprises: a first-stage exchanger, a second-stage exchanger and a third-stage exchanger; and the slurry is sequentially subjected to heat exchange and temperature rise through the first-stage exchanger, the second-stage exchanger and the third-stage exchanger and then is conveyed to the catalytic oxidation reaction kettle, and the liquid outlet of the gas-liquid separator is connected with the heat medium inlet of the second-stage exchanger.

In some optional embodiments, the medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem further comprises: a heat supply compensation module; the heat supply compensation module includes: a heat conducting oil furnace and an oil pump; and the heat supply compensation module drives a medium in the heat-conducting oil furnace to perform liquid phase circulation by using the oil pump, and returns heat energy to the heat-conducting oil furnace for reheating after the heat energy is conveyed to the third-stage exchanger.

In some optional embodiments, the medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem further comprises a dosing tank, a homogenizer, a middle tank, a heat exchanger and a high-pressure pump which are connected in sequence; the slurry sequentially passes through the proportioning tank, the homogenizer, the heat exchanger and the intermediate tank and is conveyed to a refrigerant inlet of the primary exchanger by the high-pressure pump; a refrigerant inlet of the heat exchanger is connected with a discharge hole of the homogenizer, and a refrigerant outlet of the heat exchanger is connected with a feed inlet of the intermediate tank; and the air outlet of the gas-liquid separator is connected with a heat medium inlet of the heat exchanger.

In some optional embodiments, the medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem further comprises a low-pressure separation tank, a plate-and-frame filter press and a filtrate tank which are connected in sequence; and the carbonized slurry discharged by the gas-liquid separator is sequentially subjected to heat exchange by the secondary exchanger and the primary exchanger and then is conveyed to the low-pressure separation tank, the low-temperature carbonized slurry is injected into the plate-and-frame filter press for solid-liquid separation, and the carbonized filtrate is collected by the filtrate tank.

In some optional embodiments, the medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem further comprises: a tail gas treatment module; the tail gas treatment module comprises: and the biological deodorization device is used for deodorizing noncondensable catalytic tail gas generated by the gas-liquid separator and the low-pressure separation tank and then discharging the tail gas.

In some alternative embodiments, the pyrolytic carbonization sub-system comprises: the first vertical pyrolysis machine and the second vertical pyrolysis machine are connected in series; and the semi-dried biochar cake output by the medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem is stirred in a reaction kettle of the first vertical pyrolysis machine in a high-temperature oxygen-isolated state through a central shaft, is uniformly heated to raise the temperature to perform pyrolysis carbonization, and the generated pyrolysis gas, tar and carbon slag enter the second vertical pyrolysis machine, and are subjected to secondary pyrolysis in the second vertical pyrolysis machine to generate sludge-based biochar.

In some optional embodiments, the pyrolytic carbonization sub-system further comprises: a pyrolysis gas purification module; the pyrolysis gas purification module comprises: the first vertical pyrolysis machine and the second vertical pyrolysis machine generate pyrolysis gas which is conveyed to the spray tower when being pyrolyzed and carbonized, and tar and dust are removed by the spray tower.

In some optional embodiments, the pyrolytic carbonization sub-system further comprises: the flue gas heat supply module is used for heating the first vertical pyrolysis machine and the second vertical pyrolysis machine; the flue gas heat supply module includes: the hot blast stove ablates harmful gas generated by the flue gas heat supply module and simultaneously supplies the generated heat to the first vertical pyrolysis machine; and conveying the pyrolysis gas exhausted by the spray tower to the combustor for secondary ablation.

In some optional embodiments, the pyrolytic carbonization sub-system further comprises: and the air mixing tank is used for mixing air and pyrolysis gas exhausted by the second vertical pyrolysis machine and supplying air to the air blower.

In some optional embodiments, the pyrolytic carbonization sub-system further comprises: the device comprises a storage bin, a screw conveyor, a biomass bin, a feeding sealing machine and a discharging sealing machine; the semi-dried biochar cakes output by the plate-and-frame filter press are conveyed to the storage bin to be stored, and the semi-dried biochar cakes are conveyed to the feeding sealing machine by the spiral conveyor; the feeding sealing machine and the discharging sealing machine are respectively arranged on the feeding side and the discharging side of the first vertical pyrolysis machine and the second vertical pyrolysis machine; the feeding sealing machine and the hopper of the discharging sealing machine rotate continuously to grab materials into and out of the rotary drum for feeding and discharging.

The utility model discloses compare with traditional sludge treatment mode, really realized minimizing, stabilization, innoxious, the resourceization of mud, solved difficult problems such as environmental security, the stage operation shows to have following advantage and positive effect:

1. and (3) reduction: the amount of sludge can be reduced to 1.7-1.8 t of sludge-based biochar by carbonization every 10t of sludge with the water content of 80 percent, and the sludge reduction is more than or equal to 80 percent;

2. and (3) stabilizing: the sludge-based biochar which is a final product of pyrolysis almost does not contain degradable organic matters, and the stabilization is thoroughly realized;

3. harmlessness: because the sludge is subjected to pyrolysis and carbonization in a completely closed device by oxygen separation, heavy metals are solidified at high temperature, and secondary pollution to the environment is avoided to the greatest extent;

4. resource utilization: the sludge is a combination of organic matters, and biomass energy and biochar products generated after harmless treatment can be sold to units such as landscaping units, gardening units and the like as landscaping base fertilizer raw materials and soil improvement materials for landscaping and nursery cultivation, so that the municipal sludge is recycled and is 100 percent recycled;

5. the economic efficiency is as follows: the sludge treatment by the pyrolysis carbonization method is carried out in a fully closed state, so that the heat loss is low and the energy consumption is low;

6. controllability: the pyrolysis process is applied to the treatment of sludge in a sewage treatment plant, and governments and sewage treatment plants have controllability on the whole process of sludge treatment.

Drawings

FIG. 1 is a schematic view of a municipal sludge pyrolysis treatment system of the present invention.

Detailed Description

The following description and the drawings sufficiently illustrate specific embodiments of the invention to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. The examples merely typify possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in or substituted for those of others.

In some illustrative embodiments, as shown in fig. 1, a municipal sludge pyrolysis treatment system is provided, and particularly, a medium-temperature and medium-pressure biochemical sludge thermal oxidation treatment system process of high-water content organic-rich solid waste is used as a dehydration reduction pretreatment device, and a novel vertical catalytic oxidation reaction kettle is used as a core treatment device to achieve a complete set of final treatment process of sludge. The core process comprises the following steps: a medium-temperature medium-pressure hydrothermal catalytic oxidation process and a pyrolysis carbonization process.

The municipal sludge pyrolysis treatment system of the invention comprises: the system comprises a medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem and a pyrolysis carbonization subsystem, wherein the output side of the medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem is connected with the input side of the pyrolysis carbonization subsystem. The medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem is used for carrying out catalytic oxidation dehydration decrement pretreatment on the slurry to generate a biochar cake; and the pyrolysis carbonization subsystem is used for carrying out pyrolysis carbonization treatment on the biochar cake to output sludge-based biochar.

Municipal sludge with the water content of more than or equal to 90 percent and fluidity is firstly put into a reaction kettle of a medium-temperature medium-pressure hydrothermal catalytic oxidation subsystem with the pressure of 2.5-5.0 Mpa and the temperature of 180-280 ℃ for catalytic oxidation dehydration reduction pretreatment. Under the condition of proper catalysis, the molecular structure of biomass in the sludge is broken, the biochar pulp is injected into a plate-frame filter press in batches, the biochar pulp is mechanically dehydrated, and a biochar cake with the water content of about 30 percent is obtained; finally, the sludge is pyrolyzed and carbonized through a pyrolysis and carbonization subsystem to generate sludge-based biochar with the water content of about 3 percent.

The medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem comprises: the system comprises a batching tank 1, a homogenizer 2, a heat exchanger 3, a middle tank 4, a high-pressure pump 5, a heat exchange device, a catalytic oxidation reaction kettle 9, a gas-liquid separator 10, a low-pressure separation tank 11, a plate-and-frame filter press 12, a collection tank 20, a filtrate tank 21, a heat supply compensation module 23 and a tail gas treatment module 26.

Wherein, heat transfer device includes: a primary exchanger 6, a secondary exchanger 7 and a tertiary exchanger 8.

Wherein, heat supply compensation module 23 includes: a heat conducting oil furnace 231 and an oil pump 232.

The proportioning tank 1, the homogenizer 2, the heat exchanger 3, the intermediate tank 4 and the high-pressure pump 5 are connected in sequence; the slurry passes through a proportioning tank 1, a homogenizer 2, a heat exchanger 3 and an intermediate tank 4 in sequence and is conveyed to a refrigerant inlet of a primary exchanger 6 by a high-pressure pump 5; a refrigerant inlet of the heat exchanger 3 is connected with a discharge hole of the homogenizer 2, and a refrigerant outlet of the heat exchanger 3 is connected with a feed inlet of the intermediate tank 4; the gas outlet of the gas-liquid separator 10 is connected with the heating medium inlet of the heat exchanger 3.

Batching jar 1 is the device that is used for buffering, storage, stirring, allotment mud, and the moisture content is about 98% wet mud, stirs at 15 ~ 120r/min constant speed through batching jar 1 and constantly rolls and make mud reach the purpose of misce bene to be furnished with level gauge and weighing equipment, measure the mud volume or the weight in the jar.

The homogenizer 2 is used for homogenizing and dispersing the sludge, and the homogenizer 2 is used for overcoming the non-uniformity of slurry feeding, adjusting the variation of the sludge quality, the sludge quantity and the sludge temperature of the slurry in a balanced manner, storing surplus and supplementing shortage, so that the fed slurry quantity is uniform, and the impact influence of the non-uniformity of the slurry on the subsequent process is reduced.

The heat exchanger 3 is an energy-saving device for realizing heat transfer between materials between two or more fluids with different temperatures. The heat energy of the high-temperature noncondensable carbonized tail gas after the high-temperature oxidation of the filtrate by the gas-liquid separator 10 is used for preheating the slurry by the heat exchanger 3, and the hot fluid with higher temperature, namely part of the heat energy of the noncondensable carbonized tail gas generated in the high-temperature oxidation filtrate, is transferred to the cold fluid with lower temperature, namely the slurry, so that the temperature of the fluid of the slurry is increased, and the gas temperature of the noncondensable carbonized tail gas is reduced, thereby meeting the requirements of process conditions. The slurry is preheated to T1 to become preheated slurry, T1 is 50-60 ℃, preferably 50 ℃, and the slurry is subjected to subsequent treatment. The invention fully utilizes the residual heat energy in the system, realizes the energy saving and high efficiency of the system operation and improves the energy utilization rate.

The intermediate tank 4 is used for storing and transferring preheated slurry.

The high-pressure pump 5 is a device for providing high-pressure power, and the preheated slurry is continuously pumped into the primary exchanger 6 through the high-pressure pump 5, so that the preheated slurry with poor fluidity is continuously and stably pushed to a subsequent treatment system.

The first-stage exchanger 6, the second-stage exchanger 7 and the third-stage exchanger 8 are used in series to transfer part of the heat of the hot fluid to the cold fluid. The medium with high temperature and the medium with low temperature flow in the space separated by the wall surface, and heat conduction and fluid convection through the wall surface exchange heat. The slurry is sequentially subjected to heat exchange and temperature rise through a first-stage exchanger 6, a second-stage exchanger 7 and a third-stage exchanger 8 and then conveyed to a catalytic oxidation reaction kettle 9, and a liquid outlet of a gas-liquid separator 10 is connected with a heat medium inlet of the second-stage exchanger 7.

The primary exchanger 6 receives preheated slurry continuously pumped under the drive of the high-pressure pump 5, and the temperature is raised to T2, wherein the temperature of T2 is 80-120 ℃, and the preferred temperature is 120 ℃; meanwhile, the medium-temperature carbonized slurry after heat exchange from the secondary exchanger 7 is received by the primary exchanger 6 and enters the primary exchanger 6 to exchange heat with the preheated slurry, the temperature of the low-temperature carbonized slurry after the secondary heat exchange is reduced to T7, the temperature of T7 is 50-70 ℃, and 70 ℃ is preferred.

The slurry is changed into medium-temperature slurry in a secondary exchanger 7 after heat exchange by a primary exchanger 6, the temperature is raised to T3, the temperature of T3 is 140-190 ℃, and the optimal temperature is 180 ℃. Meanwhile, the secondary exchanger 7 receives the high-temperature carbonized slurry from the gas-liquid separator 10, returns to the secondary exchanger 7, exchanges heat with the medium-temperature slurry, and reduces the temperature to T8 after heat exchange, wherein the temperature of T8 is 140-170 ℃, and the temperature is preferably 150 ℃.

The obtained medium-temperature slurry is continuously pushed into a third-stage exchanger 8 to be subjected to heat exchange to obtain high-temperature slurry, the temperature is raised to T4, the T4 is 220-280 ℃, and the preferable temperature is 250 ℃. The third-stage exchanger 8 is supplied with heat by a heat supply compensation module 23, compensates for system heat loss, and exchanges heat between slurry and heat-conducting oil by flowing the heat-conducting oil and the slurry in a space separated by a wall surface and by convection of heat-conducting oil and fluid on the wall surface.

The refrigerant outlet of the heat exchange device is connected with the feed inlet of the catalytic oxidation reaction kettle 9, the discharge outlet of the catalytic oxidation reaction kettle 9 is connected with the feed inlet of the gas-liquid separator 10, and the liquid outlet of the gas-liquid separator 10 is connected with the heat medium inlet of the heat exchange device. Therefore, the slurry is heated by heat exchange of the heat exchange device and then is conveyed to the catalytic oxidation reaction kettle 9 for catalytic oxidation, the high-temperature oxidation filtrate after catalytic oxidation is conveyed to the gas-liquid separator 10, and the high-temperature carbonization slurry separated by the gas-liquid separator 10 flows back to the heat exchange device for preheating the slurry.

The catalytic oxidation reaction kettle 9 is the core of the whole process. The high-temperature slurry is preheated and then enters a catalytic oxidation reaction kettle 9, the pH of the high-temperature slurry in the reaction kettle is controlled to be in an acid environment under the action of an additive in an environment with the pressure of 2.5-5.0 Mpa and the temperature of 180-280 ℃, organic matter cells in the high-temperature slurry realize wall breaking under the condition of medium temperature and medium pressure, combined water is converted into free water to be released, meanwhile, carbohydrate substances are converted, and carbon-like substances are formed and combined with high-temperature oxidation filtrate while heat is released, so that the high-temperature slurry is liquefied, wall breaking, decomposition, carbonization and polymerization processes, the physical and chemical shapes of the slurry are changed, and the dehydration performance is greatly improved. The temperature of the high-temperature oxidation liquid is still 250 ℃, and the catalyzed high-temperature oxidation filtrate enters a gas-liquid separator 10 for gas-liquid separation.

The gas-liquid separator 10 slows down the flow rate of the high-temperature oxidation filtrate by changing the rising flow rate, so that bubbles rise in the chamber. When air is gathered at the top, the liquid level is reduced until the lower liquid level sensor detects a low liquid level signal and sends an opening signal to the exhaust valve, and the non-condensable carbonized tail gas is released through the exhaust port. As the uncondensed carbonized tail gas is discharged, the liquid level rises until the upper liquid level sensor detects a high liquid level signal and instructs the valve to close. The high-temperature carbonized slurry separated by the gas-liquid separator 10 returns to the secondary exchanger 7 for heat exchange. The high-temperature carbonized slurry obtained by gas-liquid separation of the high-temperature oxidation liquid subjected to the carbonization reaction by the gas-liquid separator 10 is subjected to heat energy recovery by the secondary exchanger 7 and the primary exchanger 6, and is used for preheating medium-temperature slurry and low-temperature slurry, so that the optimization of the operation energy consumption of the system is realized; the low-temperature carbonized slurry after heat exchange and temperature reduction in sequence enters a low-pressure separation tank 11 after passing through a pressure controller.

The low-pressure separation tank 11, the plate-and-frame filter press 12 and the filtrate tank 21 are sequentially connected, carbonized slurry discharged from the gas-liquid separator 10 is sequentially subjected to heat exchange by the secondary exchanger 7 and the primary exchanger 6 and then is conveyed to the low-pressure separation tank 11, the low-temperature carbonized slurry is injected into the plate-and-frame filter press 12 for solid-liquid separation, and the carbonized filtrate is collected by the filtrate tank 21.

The low-pressure separation tank 11 provides a space for rapid fluid vaporization and vapor-liquid separation, and the specially designed pressure relief system continuously discharges and buffers the low-temperature carbonization slurry to the low-pressure separation tank 11 under the condition of ensuring the operation pressure of the system.

The biochar slurry taken from the low-pressure separation tank 11 is injected into a plate-and-frame filter press 12 in batches for solid-liquid separation, the biochar slurry is mechanically dehydrated, and biochar cakes with the water content of less than or equal to 30% are obtained. And enters the storage bin 13 for storage according to the requirements of subsequent treatment and disposal.

The collection tank 20 is provided for collecting the residue of the gas-liquid separator 10.

After the filtration of the plate-and-frame filter press 12 is finished, the separated carbonized filtrate is collected through a water pipeline below the filter plates and then flows out of a drain valve of the single filter plate to be discharged out of the plate-and-frame filter press 12. The filtrate tank 21 plays a role in collecting carbonized filtrate, and the carbonized filtrate is returned to the front section of the sewage plant for treatment after being collected.

The heating compensation module 23 includes: a heat-conducting oil furnace 231 and an oil pump 232; the heat supply compensation module 23 utilizes the oil pump 232 to drive the medium in the heat conduction oil furnace to perform liquid phase circulation, and the heat energy is conveyed to the third-stage exchanger 8 and then returned to the heat conduction oil furnace for reheating; an oil outlet of the heat conduction oil furnace 231 is connected with a heat medium inlet of the third-stage exchanger 8 through an oil pump 232, and a heat medium outlet of the third-stage exchanger 8 is connected with an oil return port of the heat conduction oil furnace 231.

The exhaust treatment module 26 includes: the biological deodorization device is used for deodorizing noncondensable catalytic tail gas generated by the gas-liquid separator 10 and the low-pressure separation tank 11 and then discharging the tail gas.

The pyrolysis carbonization subsystem comprises: the device comprises a storage bin 13, a biomass bin 14, a screw conveyor 15, a feeding sealing machine 16, a discharging sealing machine 17, a first vertical pyrolysis machine 18, a second vertical pyrolysis machine 19, an air mixing tank 22, a flue gas heat supply module 24 and a pyrolysis gas purification module 25.

The half-dried biochar cakes output by the plate-and-frame filter press 12 are conveyed to a storage bin 13 for storage, the storage bin 13 is used for storing the biochar cakes with the water content of less than or equal to 30% after catalysis, and the functions of buffering and material sealing are achieved before the sludge enters the first vertical pyrolysis machine 18.

The screw conveyor 15 conveys the semi-dried biochar cake to the feed sealer 16. The feeding sealing machine 16 and the discharging sealing machine 17 are respectively arranged on the feeding side and the discharging side of the first vertical pyrolysis machine 18 and the second vertical pyrolysis machine 19. The feeding sealing machine 16 and the discharging sealing machine 17 are used for conveying the biochar cake/outputting the sludge-based biochar, and play a role in sealing so as to prevent air from entering the reaction kettle to influence the pyrolysis reaction. Feeding the semi-dried biochar cake into a hopper, and continuously rotating under the action of external force; a spiral gripper is added at the top of the rotary drum, and the feeding speed can be controlled through the spiral rotating speed; the materials are continuously grabbed into/out of the rotary drum, so that forced feeding and discharging are realized, and the feeding and discharging capacity of the feeding and discharging device is improved.

The pyrolysis process includes the first vertical pyrolysis machine 18 and the vertical pyrolysis machine 19 of second of establishing ties, is provided with pyrolysis carbonization reation kettle heat conduction chamber between vertical pyrolysis machine heat preservation and the axis, is connected with the combustor on the pyrolysis carbonization reation kettle heat conduction chamber.

Semi-dried biochar cakes output by the medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem are stirred in a reaction kettle of the first vertical pyrolysis machine 18 in a high-temperature oxygen-isolated state through a central shaft, then are uniformly heated to raise the temperature for pyrolysis and carbonization, generated pyrolysis gas, tar and carbon slag enter the second vertical pyrolysis machine 19, and the second vertical pyrolysis machine 19 carries out secondary pyrolysis to generate sludge-based biochar.

The first vertical pyrolysis machine 18 and the second vertical pyrolysis machine 19 are always in a micro-positive pressure state.

And finally generating a stable solid product sludge-based biochar mixture in the second vertical pyrolysis machine 19, sintering heavy metals in the sludge in the mixture, discharging the sludge out of the reaction kettle through the discharging sealing machine 17, cooling, collecting and discharging the sludge out of the system to serve as a biochar product for export sales.

The pyrolysis gas purification module 25 includes: the decompression water tank 251 and the spray tower 252, and pyrolysis gas generated when the first vertical pyrolysis machine 18 and the second vertical pyrolysis machine 19 are pyrolyzed and carbonized are conveyed to the spray tower 252, and tar and dust are removed by the spray tower 252.

The flue gas heat supply module 24 is used for heating the first vertical pyrolysis machine 18 and the second vertical pyrolysis machine 19. The first vertical pyrolysis machine 18 and the second vertical pyrolysis machine 19 are both externally heated, and a flue gas heat supply module 24 is arranged outside the reaction kettle to heat the reaction kettle through a burner so as to maintain the temperature in the reaction kettle. The burner uses natural gas as fuel, and the natural gas is decompressed by the decompressor and then is subjected to air distribution combustion by the burner.

The flue gas heating module 24 includes: the burner 241, the hot-blast stove 242 and the blower 243, the hot-blast stove 242 ablates the harmful gas generated by the flue gas heat supply module, and simultaneously supplies the generated heat to the first vertical pyrolysis machine 18; the pyrolysis gas discharged from the spray tower 252 is delivered to the burner 241 for secondary ablation.

In the pyrolysis process, organic components in the sludge generate high-temperature gas, namely pyrolysis gas and a small amount of water vapor, in a high-temperature oxygen isolation state, the high-temperature gas is treated by the pyrolysis gas purification module 25 and then is sent into the flue gas heat supply module 24 through the recycling pipeline to be mixed and combusted with auxiliary fuel, namely liquefied petroleum gas, natural gas or biomass, and the high-temperature flue gas generated by combustion is used for heating the vertical pyrolysis machine and providing a heat source for the pyrolysis machine.

The burner 241 is a combination burner for use with the stove 242. The natural gas and the pyrolysis gas can be used independently or simultaneously: natural gas is used when the temperature of the device is raised; after the pyrolysis gas is generated after feeding, the natural gas and the pyrolysis gas are used simultaneously; or when the amount of the pyrolysis gas is enough, the natural gas is closed, and the pyrolysis gas is used independently. The hot blast stove 242 is used for burning harmful gas generated in the device, and simultaneously, the generated heat is directly supplied to the pyrolysis machine for use, so that pollution is eliminated, and energy is saved. After most of tar and dust are removed from gaseous products generated by pyrolysis in the pyrolysis carbonization procedure through the spray tower 252, the gas is conveyed to the combustor 241 for secondary ablation and then is completely recycled; and (4) collecting and recycling heavy components separated from the gaseous products, and mixing the heavy components with the sludge for secondary pyrolysis.

The air mixing tank 22 is used for mixing air with pyrolysis gas discharged from the second vertical pyrolysis unit 19 and supplying air to the blower 243.

The secondary pollutants generated by the invention are wastewater and waste gas: the waste gas is noncondensable catalytic tail gas discharged by a gas-liquid separator 10 and a low-pressure separation tank 11 in the medium-temperature medium-pressure thermal oxidation pretreatment process, and is discharged after reaching the standard after being deodorized; the wastewater is mainly carbonized filtrate of the plate-and-frame filter press 12 and is discharged into the front end of a sewage treatment plant for treatment.

The intermediate-temperature medium-pressure hydrothermal catalytic oxidation technology of the sludge starts from changing the physical characteristics of the sludge, develops and breaks through the conventional physical and chemical auxiliary process, treats and disposes the sludge by utilizing the high-pressure chemical principle, revolutionarily breaks through the capacity bottleneck of mechanical energy dehydration, completely subverts the technical route that the traditional process needs dehydration firstly and then drying, and generates the sludge with the water content of 90 percent into a charcoal cake with the water content of 30 percent; organic matters and water content in the charcoal cake are further reduced through a pyrolysis process, green sludge-based charcoal is generated, the charcoal can be widely applied to agriculture, gardens, soil remediation, building material manufacturing and the like, and the running cost is moderate.

On the basis of analyzing the inherent problems of the current sludge treatment technology, the invention is contrary to the idea of selecting and developing the route of the traditional sludge treatment technology: the traditional sludge aims at exploring, developing and improving the mechanical energy dehydration effect and improving the mechanical energy dehydration efficiency, and the water content of the sludge is reduced as much as possible; the process utilizes municipal sludge with high water content and rich organic matters, which is more than or equal to 90 percent, as a pretreatment target of the pyrolysis process, controls the temperature of a reaction kettle at 180-280 ℃ and the corresponding pressure at 2.5-5.0 Mpa for wet catalytic oxidation, and reduces or even avoids a novel process route which aims at relying on water evaporation in the sludge pyrolysis drying stage.

And (3) heating and carbonizing the sludge in a vertical pyrolysis furnace, and cooling and collecting the carbonized solid product sludge-based biochar. Pyrolysis gas generated in the sludge pyrolysis carbonization process is treated and then is sent into the flue gas heat supply module through the recycling pipeline, and is mixed and combusted with auxiliary fuel, namely liquefied petroleum gas, natural gas or biomass, and high-temperature flue gas generated by combustion is used for heating the vertical pyrolysis furnace and providing a heat source for the pyrolysis furnace.

The invention treats the flowing biochemical sludge by a special process of sludge medium-temperature medium-pressure oxidation technology: separating mud from water after breaking the wall of microbial cells in the sludge; 100% of microorganisms such as pathogens and the like in the sludge are removed, so that the environmental biotoxicity of the sludge is thoroughly eliminated; organic carbon in the sludge forms a compound structure, and the compound structure is converted into a biochemical organic matter after cracking and oxidative degradation, and part of the biochemical organic matter is deeply mineralized into carbon dioxide to be removed; inorganic pollutants in the sludge are discharged along with the carbonized product and form a solid substance which can be recycled. And then performing dry distillation on 30% of sludge treated by a specific process of a medium-temperature medium-pressure oxidation technology under an anaerobic condition to evaporate moisture of the sludge, carbonizing most organic matters, wherein the carbonized sludge is similar to activated carbon, and pyrolyzing 1t of 80% of sludge to finally obtain 170-180 Kg of carbon slag with stable properties and water content of about 3%. The invention conforms to the principles of sludge treatment reduction, stabilization, harmlessness and recycling, thereby realizing the recycling of municipal sludge and the cyclic development of treating wastes with wastes, having low operation cost, being suitable for the installation beside a treatment facility pool of a sewage plant, and having the characteristics of good continuity, stable operation, small occupied space and the like.

The above embodiment is the preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above embodiment, and any other changes, modifications, replacements, combinations, simplifications, equivalent replacement modes, which are not departed from the spirit and principle of the present invention, should be included in the protection scope of the present invention.

Claims (12)

1. Municipal sludge pyrolysis treatment system, its characterized in that includes:

the medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem is used for carrying out catalytic oxidation dehydration decrement pretreatment on the slurry to generate a biochar cake;

and the pyrolysis carbonization subsystem is used for carrying out pyrolysis carbonization treatment on the biochar cake to output sludge-based biochar.

2. The municipal sludge pyrolysis treatment system of claim 1, wherein the medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem comprises: the device comprises a heat exchange device, a catalytic oxidation reaction kettle and a gas-liquid separator; the output end of the heat exchange device is connected with the input end of the catalytic oxidation reaction kettle; the output end of the catalytic oxidation reaction kettle is connected with the input end of the gas-liquid separator; and the liquid outlet of the gas-liquid separator is connected with the input end of the heat exchange device.

3. The municipal sludge pyrolysis treatment system of claim 2, wherein the heat exchange device comprises: the first-stage exchanger, the second-stage exchanger and the third-stage exchanger are connected in sequence; and the liquid outlet of the gas-liquid separator is connected with the heat medium inlet of the secondary exchanger.

4. The municipal sludge pyrolysis treatment system of claim 3, wherein the medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem further comprises: a heat supply compensation module; the heat supply compensation module includes: a heat conducting oil furnace and an oil pump; the oil pump is connected with the heat-conducting oil furnace and is used for driving a medium in the heat-conducting oil furnace to perform liquid phase circulation; the heat-conducting oil furnace is connected with the third-stage exchanger.

5. The municipal sludge pyrolysis treatment system according to claim 4, wherein the medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem further comprises a dosing tank, a homogenizer, an intermediate tank, a heat exchanger and a high-pressure pump which are connected in sequence; the output end of the high-pressure pump is connected with the refrigerant inlet of the primary exchanger; a refrigerant inlet of the heat exchanger is connected with a discharge hole of the homogenizer, and an exchange medium outlet of the heat exchanger is connected with a feed inlet of the intermediate tank; and the air outlet of the gas-liquid separator is connected with a heat medium inlet of the heat exchanger.

6. The municipal sludge pyrolysis treatment system according to claim 5, wherein the medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem further comprises a low-pressure separation tank, a plate-and-frame filter press and a filtrate tank which are connected in sequence; the outlet of the first-stage exchanger is connected with the low-pressure separation tank, the discharge port of the low-pressure separation tank is connected with the plate-and-frame filter press, and the liquid outlet of the plate-and-frame filter press is connected with the filtrate tank.

7. The municipal sludge pyrolysis treatment system of claim 6, wherein the medium-temperature and medium-pressure hydrothermal catalytic oxidation subsystem further comprises: a tail gas treatment module; the tail gas treatment module comprises: and the biological deodorization device is connected with the gas-liquid separator and the low-pressure separation tank.

8. The municipal sludge pyrolysis treatment system of claim 7, wherein the pyrolysis carbonization subsystem comprises: the first vertical pyrolysis machine and the second vertical pyrolysis machine are connected in series; the first vertical pyrolysis machine is connected with the medium-temperature medium-pressure hydrothermal catalytic oxidation subsystem.

9. The municipal sludge pyrolysis treatment system of claim 8, wherein the pyrolysis carbonization subsystem further comprises: a pyrolysis gas purification module; the pyrolysis gas purification module comprises a pressure relief water tank and a spray tower, and the spray tower is connected with the second vertical pyrolysis machine.

10. The municipal sludge pyrolysis treatment system of claim 9, wherein the pyrolysis carbonization subsystem further comprises a flue gas heating module that heats the first vertical pyrolysis machine and the second vertical pyrolysis machine; the flue gas heat supply module includes: the hot blast stove is connected with the first vertical pyrolysis machine; and the outlet of the spray tower is connected with the combustor.

11. The municipal sludge pyrolysis treatment system of claim 10, wherein the pyrolysis carbonization subsystem further comprises an air mixing tank for mixing air with flue gas discharged from the second vertical pyrolysis unit, the air mixing tank being connected to the blower.

12. The municipal sludge pyrolysis treatment system of claim 11, wherein the pyrolysis carbonization subsystem further comprises a storage bin, a screw conveyor, a biomass bin, a feed sealer, and a discharge sealer; the discharge port of the plate-and-frame filter press is connected with the storage bin; the discharge hole of the spiral conveyor is connected with the feeding sealing machine; the feeding sealing machine and the discharging sealing machine are respectively arranged on the feeding side and the discharging side of the first vertical pyrolysis machine and the second vertical pyrolysis machine.

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