A pretreatment system for organic waste with high water content

Abstract

This invention discloses a pretreatment system for high-moisture organic waste, used in the field of organic waste treatment. It includes: a hydrolysis fluidization device with a hydrolysate outlet, an ammonia outlet, a slurry inlet, and a steam inlet; a pressure relief tower, the inlet of which is connected to the hydrolysate outlet; and a slurry homogenizing device, the output of which is connected to the slurry inlet via a lifting device. This invention utilizes the homogenizing device to treat organic waste into a slurry state, and the hydrolysis fluidization device to convert long-chain organic matter in the slurry into short-chain organic matter. Some substances that are difficult to decompose in traditional anaerobic reactors become biodegradable after hydrolysis fluidization, improving the biodegradability of the slurry. Furthermore, this invention also allows the hydrolysate to flow through the pressure relief tower, providing maintenance time for subsequent processes.

Description

Technical Field

[0001] The invention relates to the field of organic waste treatment, in particular to a pretreatment system for high-water-content organic waste. Background Art

[0002] Highly water-containing organic wastes include medicinal mud, livestock manure, human feces, kitchen waste, municipal sludge, food industry sludge, etc. At present, the common method for treating them is anaerobic biochemical treatment. However, these organic wastes have long molecular chains and are difficult to decompose, making their biodegradability poor, which affects the effect of anaerobic biochemical treatment. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a pretreatment system for organic waste with high water content, which improves the biodegradability of organic matter in the waste.

[0004] The technical solution adopted by the present invention is:

[0005] A pretreatment system for high-water-content organic waste, comprising:

[0006] A hydrolysis fluidization device having a hydrolysis liquid outlet, an ammonia outlet, a slurry inlet and a steam inlet;

[0007] A pressure release tower, the inlet of the pressure release tower is connected to the outlet of the hydrolyzate;

[0008] The homogenizing device has an output end connected to the slurry inlet through a lifting device.

[0009] As a further improvement of the present invention, it also includes an ammonia crystallization device, and the ammonia outlet is connected to the ammonia crystallization device through a pipeline.

[0010] As a further improvement of the present invention, the pressure release tower is provided with a gas outlet, and the gas outlet of the pressure release tower leads to the ammonia crystallization device.

[0011] As a further improvement of the present invention, the pressure release tower is provided with a liquid outlet, and a reflux component is provided between the liquid outlet and the homogenizing device, and the reflux component refluxes the hydrolyzate discharged from the pressure release tower to the homogenizing device.

[0012] As a further improvement of the present invention, the homogenization device includes a homogenization pool and a homogenization tank. The outlet of the homogenization pool is provided with a cutting pump, the outlet of the cutting pump is provided with a feeding pump, the outlet of the feeding pump is connected to the homogenization tank through a pipeline, and the outlet of the homogenization tank is connected to the hydrolysis fluidization device through a pipeline.

[0013] As a further improvement of the present invention, a feed pressurizing component serving as a lifting device is provided on the pipeline connecting the homogenization tank and the slurry inlet.

[0014] As a further improvement of the present invention, it also includes a heat exchanger, which connects the outlet of the hydrolyzate to the inlet of the pressure release tower, and the heat exchanger connects the outlet of the homogenization device to the inlet of the slurry.

[0015] As a further improvement of the present invention, the hydrolysis fluidization device comprises:

[0016] The fluidized bed has an overflow port at the top and a sludge discharge port at the bottom, and the slurry inlet leads to the fluidized bed;

[0017] A shell is sleeved on the outside of the fluidized bed, an overflow cavity is formed between the shell and the fluidized bed, an ammonia outlet is located at the top of the shell and communicates with the overflow cavity, and a hydrolyzate outlet is arranged at the bottom of the shell and leads to the overflow cavity;

[0018] And a steam distributor is arranged at the bottom of the fluidized bed body, and the steam distributor is externally connected to a water vapor input pipe through a steam inlet.

[0019] As a further improvement of the present invention, the steam spraying direction of the steam distributor is upward.

[0020] As a further improvement of the present invention, the homogenizing device is provided with an exhaust port leading to the ammonia crystallization device, and a mud discharge port is provided at the bottom end of the homogenizing device, and the mud discharge port is connected to the mud discharge port through a mud discharge pipe.

[0021] The beneficial effects of the present invention are as follows: the present invention utilizes a homogenizing device to process organic waste into a slurry state, a hydrolysis and fluidization device converts long-molecule-chain organic matter in the slurry into short-molecule-chain organic matter, and some substances that are difficult to decompose in traditional anaerobic reactors are converted into biodegradable substances after hydrolysis and fluidization, thereby improving the biodegradability of the slurry; in addition, the present invention also allows the hydrolyzate to flow through a pressure release tower, thereby providing maintenance time guarantee for subsequent processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention is further described below in conjunction with the accompanying drawings and implementation modes.

[0023] Figure 1 It is a schematic diagram of the present invention;

[0024] Figure 2 It is a schematic diagram of the hydrolysis fluidized bed. DETAILED DESCRIPTION

[0025] like Figure 1 and Figure 2 The pretreatment system of high-water-content organic waste includes a hydrolysis fluidization device, a homogenization device and a pressure release tower 5.

[0026] The homogenizing device is used to disperse the solid matter in the organic waste by stirring, cutting or other means, and mix it with water into a slurry to facilitate subsequent treatment.

[0027] The hydrolysis fluidization device has a hydrolyzate outlet 1, an ammonia outlet 2, a slurry inlet 3 and a steam inlet 4, wherein the slurry inlet 3 is connected to a lifting device to input the external slurry into the hydrolysis fluidization device. In the hydrolysis fluidization device, the hot steam causes the nutrients in the slurry to be hydrolyzed into polysaccharides, organic acids, peptides, enzymes and other substances. When the protein is hydrolyzed, the nitrogen element NH4 + It is decomposed into unstable free ammonia HN3·H2O (hydrated ammonia), which is further converted into ammonia gas under the action of heat and discharged through the ammonia gas outlet 2.

[0028] The inlet of the pressure relief tower 5 is connected to the hydrolyzed liquid outlet 1 through a pipeline to receive the hydrolyzed liquid discharged from the hydrolysis fluidization device. Because the hydrolyzed liquid discharged has a certain pressure, the pressure relief tower 5 can release the pressure in the hydrolyzed liquid, and at the same time play the role of temporarily storing the hydrolyzed liquid, providing buffer time and maintenance time for subsequent processes. Specifically, a nozzle 52 is provided at the top of the pressure relief tower 5, and the hydrolyzed liquid is passed into the nozzle to be sprayed into the inner cavity of the pressure relief tower 5, and the hydrolyzed liquid of the pressure relief tower 5 is discharged from the bottom.

[0029] Further preferably, the pretreatment system further comprises an ammonia crystallization device 6. The ammonia outlet 2 of the hydrolysis fluidized bed device is connected to the ammonia crystallization device 6 through a pipeline, and a valve is also provided on the pipeline for regular discharge. The ammonia crystallization device 6 is in the shape of a container, sulfuric acid is injected into it, and ammonia reacts with sulfuric acid to generate ammonium sulfate, and the chemical reaction formula is as follows:

[0030] 2NH3+H2SO4→(NH4)2SO4.

[0031] The generated ammonium sulfate can be dried and used to make fertilizer after being discharged.

[0032] More preferably, the pressure relief tower 5 is provided with a gas outlet 51 at the top, and the gas outlet 51 of the pressure relief tower 5 leads to the ammonia crystallization device 6. The gas formed after the hydrolyzate is volatilized also contains ammonia, and thus is discharged into the ammonia crystallization device 6 to form a solid state.

[0033] Further preferably, the pressure relief tower 5 is provided with a liquid outlet at the bottom end, and the liquid outlet is connected to a drain pipe, which can be passed into a collecting container not shown in the figure, and a reflux component 7 is provided between the collecting container and the homogenization device, such as a reflux pump, and the reflux component 7 refluxes the hydrolyzate discharged from the pressure relief tower 5 to the homogenization device for diluting the organic waste.

[0034] Further preferably, the homogenizing device includes a homogenizing pool 8 and a homogenizing tank 9. A stirring paddle 81 is provided inside the homogenizing pool 8, a cutting pump 10 is provided at the outlet of the homogenizing pool 8, a feed pump 11 is provided at the outlet of the cutting pump 10, and the homogenizing pool 8 can also be refluxed through a pipeline. The outlet of the feed pump 11 is connected to the homogenizing tank 9 through a pipeline, and the outlet of the homogenizing tank 9 is connected to the hydrolysis fluidization device through a pipeline. The organic waste can be mixed with water in the homogenizing pool 8, pre-mixed by the stirring paddle, and then output and homogenized after being transported and stirred by the cutting pump 10; during the stirring process, the organic waste circulates between the homogenizing pool 8 and the cutting pump 10, and the impurities brought in by the organic waste are crushed under the repeated cutting of the cutting pump 10; the organic waste after stirring and cutting is diluted into slurry, and the slurry is continuously refluxed, circulated, stirred and cut until the homogenizing pool 8 is filled with slurry and the stirring is completed, and the slurry is pumped into the homogenizing tank 9 through the slurry feeding pump 11. A stirrer is also provided in the homogenizing tank 9 to keep the slurry uniform.

[0035] Further preferably, a feed pressurizing component is provided on the pipeline connecting the homogenizing tank 9 and the slurry inlet 3. The feed pressurizing component can input the slurry into the hydrolysis fluidization device and pressurize the slurry to a suitable pressure, so that the slurry and the hydrolysis fluidization device have a suitable pressure value. The preferred feed pressurizing component is a high-pressure plunger pump 20.

[0036] Further preferably, the pretreatment system further includes a heat exchanger 12. The heat exchanger 12 is a plate heat exchanger, which connects the hydrolyzed liquid outlet 1 to the inlet of the pressure relief tower 5, and connects the outlet of the homogenizing device to the slurry inlet 3. The slurry entering the slurry inlet 3 can be heated by the heat in the hydrolyzed liquid, so that the system reasonably utilizes heat and saves costs.

[0037] The hydrolysis fluidization apparatus is described below.

[0038] The hydrolysis fluidization device includes a fluidized bed 13 , a shell 15 and a steam distributor 16 .

[0039] The fluidized bed 13 is container-shaped, and an overflow port 14 is formed at the top thereof in an open shape, and the hydrolyzed liquid overflowing in the fluidized bed 13 can flow out from the overflow port 14. A mud discharge port is provided at the bottom of the fluidized bed 13, and the slurry inlet 3 leads to the fluidized bed 13 and is externally connected to a feed pipe; the feed pipe is higher than the mud discharge port but also close to the bottom of the fluidized bed 13.

[0040] The steam distributor 16 is arranged at the bottom of the fluidized bed 13, and its steam injection direction is preferably upward and leads to the fluidized bed 13, forming water vapor rising from bottom to top. The steam distributor 16 is connected to the water vapor input pipe 17 through the steam inlet 4, which is used to introduce high-pressure and high-temperature water vapor into the fluidized bed 13.

[0041] The shell 15 is sleeved on the outside of the fluidized bed 13 so that the fluidized bed 13 is located in the middle. The top wall of the shell 15 is separated from the overflow port 14 by a distance in the height direction. The outer wall of the shell 15 is separated from the outer wall of the fluidized bed 13 by a distance to form an overflow cavity. The hydrolyzed liquid flowing out of the overflow port 14 can enter the overflow cavity. The bottom of the shell 15 is also provided with a hydrolyzed liquid outlet 1 leading to the overflow cavity, which is used to guide the hydrolyzed liquid in the overflow cavity out of the shell 15. The ammonia outlet 2 is arranged at the top of the shell 15 and connected to the overflow cavity to discharge the ammonia generated during the hydrolysis. The ammonia outlet 2 is connected to a discharge valve 41 for controlling the discharge of ammonia.

[0042] Then the process of hydrolysis fluidization using the device is as follows:

[0043] The slurry is input into the fluidized bed 13, at which time the fluidized bed 13 may be in a high temperature and high pressure state by preheating and pressurizing, or the high temperature and high pressure slurry may be directly input into the closed fluidized bed 13; high temperature water vapor enters the fluidized bed 13 through the steam distributor 16 to further heat the slurry; at this time, the organic matter in the slurry will be decomposed faster, the chemical bonds of the organic matter will be broken, and the long molecular chain organic matter will be turned into short molecular chain organic matter. Some substances that are difficult to decompose in traditional anaerobic reactors will be turned into biodegradable substances after passing through the fluidized bed 13, and the biodegradability of the slurry will be greatly improved. Improvement; part of the decomposed hydrolyzate will pass over the fluidized bed 13 and enter the overflow chamber, and the undecomposed substances will continue to remain in the fluidized bed 13 for decomposition due to their large specific gravity; due to the high temperature and high pressure state, part of the organic matter and ammonia in the hydrolyzate will become ammonia-containing gas, which will be discharged from the ammonia outlet 2, and the ammonia will be discharged to the ammonia crystallization device 6 for crystallization; after running for a period of time, some organic matter (cellulose, etc.) and inorganic matter (fixed carbon, stone powder, etc.) that cannot be decomposed will remain in the fluidized bed 13. In order to ensure the hydrolysis effect, the mud outlet is opened for mud discharge in a certain production cycle.

[0044] The above process can also be simply summarized as follows: the slurry enters the fluidized bed 13, wherein the lighter suspended matter rises upward under the impetus of high-temperature and high-pressure steam, overflows the fluidized bed, and flows to the mud discharge port at the bottom, while the larger and heavier materials descend along the inner cavity wall and are flushed and hydrolyzed by the steam again, and the cycle continues; in the process of the slurry and steam rising, the steam and the slurry undergo heat exchange, and condense into water and mix into the slurry.

[0045] The principle of the above process is as follows: During the fluidization process of the device, due to the effect of heat, the nutrients in the slurry are hydrolyzed into polysaccharides, organic acids, peptides, enzymes and other substances. When the protein is hydrolyzed, the nitrogen element NH4 +It is decomposed into unstable free ammonia HN3·H2O (hydrated ammonia). Under the action of heat, the unstable free ammonia is further converted into ammonia gas and released regularly through the exhaust valve at the top of the tower. The reaction formula related to hydrolysis and deamination is as follows:

[0046] 1) NH4 + +OH - →NH3·H2O

[0047] 2) NH3·H2O→NH3↑+H2O

[0048] The organic matter is hydrolyzed and acidified into a hydrolyzate by high temperature hydrolysis. In this embodiment, the high temperature steam can be used as a solid organic fluidizing gas and a stripping gas for NH3, and is also a medium for providing the hydrolysis temperature. The high temperature steam is also high pressure, which is used to maintain the pressure in the fluidized bed 13 and raise the temperature of the slurry in the fluidized bed 13 to 120-190°C.

[0049] The heat exchanger 12 has a cold inlet and a hot outlet that are interconnected, and a hot inlet and a cold outlet that are interconnected. The hot outlet of the heat exchanger 12 is connected to the slurry inlet 3, and the cold inlet leads to the homogenization tank 9. The hot inlet of the heat exchanger 12 is connected to the hydrolyzate outlet 1 through a pipeline, and the cold outlet leads to the pressure release tower 5.

[0050] The high-pressure plunger pump 20 is used to pressurize the slurry to a suitable pressure value and then input it into the fluidized bed 13, so that the fluidized bed 13 has a "preset" pressure.

[0051] The slurry is pressurized to 0.5-1.5Mpa by a high-pressure plunger pump 20, and then enters the heat exchanger 12, where the high-temperature hydrolyzate after fluidized thermal hydrolysis is used as a heat source to preheat the slurry to 100-150°C; thereafter, the hydrolysis process is carried out according to the above-mentioned process; the hydrolyzed hydrolyzate enters the heat exchanger 121 for cooling (the heat is used to preheat the newly-input slurry), and the temperature drops to 40-60°C and is sent to subsequent processes.

[0052] In the above implementation, refer to the above reaction formula 2: NH4 + +OH - →NH3·H2O, this formula is reversible. In an acidic environment with a pH value of 4.5-5.8, when the hydrolysis temperature decreases, the free ammonia will react again to become ammonium to increase the pH of the hydrolyzate, as shown in the following reaction formula 3:

[0053] 3) NH3·H2O→NH4 + +OH -

[0054] According to reaction equations 1), 2), and 3), the amount of ammonium released from the slurry can be achieved by adjusting the pH value, and the precipitation of ammonia is closely related to the dissolved oxygen content (DO) and hydrolysis temperature of the hydrolyzate. Therefore, by adding sodium hydroxide solution in proportion to the booster plunger pump to change the pH value of the slurry and control the hydrolysis temperature, the ammonia nitrogen in the hydrolyzate can be effectively controlled. The pH value should be adjusted to a weak acidity of 5.8-6.8.

[0055] Further preferably, the top of the homogenizing tank 9 is provided with an exhaust port 19 leading to the ammonia crystallization device 6, so as to discharge the volatilized ammonia and other gases in the homogenizing tank 9. The bottom of the homogenizing tank 9 is provided with a mud discharge port 18 to discharge impurities and residues. The mud discharge port 18 is connected to the mud discharge port through a mud discharge pipe, and the discharged bottom residue can be transported outside or used for drying into fertilizer.

[0056] After the above pretreatment system and process, the BOD of the hydrolyzate will not decrease synchronously with the COD index, and the indicators such as TN and NH3 in the hydrolyzate become adjustable indicators, which greatly enhances the biodegradability of organic waste.

[0057] The above description is only a preferred embodiment of the present invention and does not constitute a limitation on the protection scope of the present invention.

Claims

1. A pretreatment system for high-water organic waste, characterized in that: include: A hydrolysis fluidization device having a hydrolysis liquid outlet (1), an ammonia outlet (2), a slurry inlet (3) and a steam inlet (4); A pressure release tower (5), wherein the inlet of the pressure release tower (5) is connected to the hydrolyzate outlet (1); A homogenizing device, the output end of which is connected to the slurry inlet (3) via a lifting device; It also includes an ammonia crystallization device (6), and the ammonia outlet (2) is connected to the ammonia crystallization device (6) through a pipeline; The pressure release tower (5) is provided with a gas outlet (51), and the gas outlet (51) of the pressure release tower (5) leads to the ammonia crystallization device (6); The pressure relief tower (5) is provided with a liquid outlet, and a reflux component (7) is provided between the liquid outlet and the homogenizing device. The reflux component (7) refluxes the hydrolyzed liquid discharged from the pressure relief tower (5) to the homogenizing device.

2. The pretreatment system for high water content organic waste according to claim 1, characterized in that: The homogenizing device comprises a homogenizing pool (8) and a homogenizing tank (9); a cutting pump (10) is provided at the outlet of the homogenizing pool (8); a feed pump (11) is provided at the outlet of the cutting pump (10); the outlet of the feed pump (11) is connected to the homogenizing tank (9) via a pipeline; and the outlet of the homogenizing tank (9) is connected to a hydrolysis fluidizing device via a pipeline.

3. The pretreatment system for high water content organic waste according to claim 2, characterized in that: A feed pressurizing component serving as a lifting device is provided on the pipeline connecting the homogenizing tank (9) and the slurry inlet (3).

4. The pretreatment system for high water content organic waste according to claim 1, characterized in that: It also includes a heat exchanger (12), wherein the heat exchanger (12) connects the hydrolyzate outlet (1) to the inlet of the pressure release tower (5), and the heat exchanger (12) simultaneously connects the outlet of the homogenization device to the slurry inlet (3).

5. The pretreatment system for high-water organic waste according to any one of claims 1 to 4, characterized in that: The hydrolysis fluidization device comprises: The fluidized bed (13) has an overflow port (14) at the top and a mud discharge port at the bottom, and the slurry inlet (3) leads to the fluidized bed (13); A shell (15) is sleeved on the outside of the fluidized bed (13), an overflow chamber is formed between the shell (15) and the fluidized bed (13), an ammonia outlet (2) is located at the top of the shell (15) and communicates with the overflow chamber, and a hydrolyzate outlet (1) is arranged at the bottom of the shell (15) and leads to the overflow chamber; And a steam distributor (16) is arranged at the bottom of the fluidized bed (13), and the steam distributor (16) is externally connected to a water vapor input pipe (17) through a steam inlet (4).

6. The pretreatment system for high water content organic waste according to claim 5, characterized in that: The steam spraying direction of the steam distributor (16) is upward.

7. The pretreatment system for high water content organic waste according to claim 5, characterized in that: The homogenizing device is provided with an exhaust port (19) leading to the ammonia crystallization device (6), and a mud discharge port (18) is provided at the bottom end of the homogenizing device. The mud discharge port (18) is connected to the mud discharge port through a mud discharge pipe.

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