A method for combined anaerobic digestion of dead livestock and poultry residues and kitchen waste slurry

Abstract

The invention discloses a method for anaerobic digestion of dead livestock and poultry residues and restaurant kitchen waste slurry. The residues of dead livestock and poultry after wet processing are mixed with water for pulping and evenly mixed with restaurant kitchen waste slurry, and then combined with anaerobic fermentation after oil separation to further reduce the residues and make resource utilization. Since the residues of dead livestock and poultry after wet processing have complex components, high organic nitrogen content, and low carbon-nitrogen ratio, which is not conducive to anaerobic digestion process, the invention utilizes the advantages of joint construction and operation of restaurant kitchen waste treatment and harmless disposal of dead livestock and poultry projects, and combines the dead livestock and poultry residues with restaurant kitchen waste slurry for anaerobic digestion. By controlling the mixing ratio of the mixed slurry and adjusting the carbon-nitrogen ratio of the mixed slurry, the carbon-nitrogen ratio requirement of the anaerobic digestion process is met, and the mixed slurry is effectively anaerobically digested for further reduction and resource utilization.

Description

Technical Field

[0001] The invention relates to the technical field of high-temperature anaerobic digestion, and in particular to a method for combined anaerobic digestion of dead livestock and poultry residues and kitchen waste slurry. Background Art

[0002] Death of livestock and poultry due to disease or disaster is a common situation in livestock and poultry breeding. However, if the dead bodies of livestock and poultry are not handled properly or are randomly discarded, it will not only cause the spread of related diseases, but also the long-term latent pathogens of livestock and poultry will cause deep pollution to the livestock and poultry breeding environment. Therefore, how to harmlessly dispose of dead livestock and poultry is a problem that must be solved in today's animal husbandry industry.

[0003] The harmless treatment of dead livestock and poultry refers to the process of safely treating and eliminating harmful biological or chemical substances in dead and diseased animals and related animal products, which is of great significance for reducing environmental pollution and ensuring food safety. The existing methods for harmless treatment of dead livestock and poultry mainly include incineration, chemical treatment, landfill, fermentation, etc. However, none of them are used as resources, and the residue treatment is relatively difficult. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a method for anaerobic digestion of dead livestock and poultry residues and food waste slurry, so as to solve the problem that the existing technology for harmless treatment of dead livestock and poultry cannot achieve resource utilization and the residue treatment is difficult.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0006] A method for combined anaerobic digestion of dead livestock and poultry residues and kitchen waste slurry, using the following process:

[0007] Crushing of dead livestock and poultry materials → Wet chemical treatment of dead livestock and poultry → Mixing of chemical treatment residues with water to make pulp → Mixing with food waste pulp and homogenizing → Degreasing of the mixed pulp, and the obtained oil is used to produce biodiesel → The remaining mixed pulp enters the anaerobic tank for anaerobic digestion process to produce biogas → Biogas purification and utilization.

[0008] Furthermore, the wet treatment method for dead livestock and poultry includes:

[0009] S11, feeding system: feeding dead livestock and poultry materials into the crushing system;

[0010] S12, Crushing system: crushing dead livestock and poultry materials;

[0011] S13, high temperature and high pressure chemical processing process: the crushed dead poultry materials are added into the high temperature and high pressure chemical processing machine through the injection pump for high temperature and high pressure wet chemical processing.

[0012] Further, the combined anaerobic digestion process comprises:

[0013] S21, discharging screw: transports the residue after chemical treatment to the mixing tank;

[0014] S22, mixing tank: mix the residue after chemical treatment with water and mix evenly to form residue slurry; the mass ratio of the slurry of dead livestock and poultry residue to the mass of dead livestock and poultry material is 2-2.5, and the measured TS needs to be less than 10%;

[0015] S23, pulping machine: the residue pulp enters the pulping machine for further crushing and pulping, and the obtained dead livestock and poultry residue pulp and restaurant kitchen waste pulp are fully mixed and evenly mixed; wherein, the mass ratio of dead livestock and poultry pulp to the mixed pulp is less than 7.5%; the mass ratio of the restaurant kitchen waste pulping volume to the restaurant kitchen waste volume is: 1-1.1, and the measured TS is about 10%;

[0016] S24, horizontal separation oil removal: the mixed slurry enters the oil removal system to separate the oil; specific steps: the mixed slurry is heated and enters the horizontal centrifuge to separate the oil phase, and the oil phase enters the butterfly centrifuge to further remove slag and water to obtain animal and plant mixed oil with a purity greater than 97%; the obtained oil is used to produce biodiesel;

[0017] S25, anaerobic tank: the mixed slurry after oil removal enters the anaerobic tank for anaerobic digestion to produce biogas, and the generated biogas is recycled;

[0018] S26. Finally, the produced biogas is purified and recycled.

[0019] Furthermore, the high temperature and high pressure chemical process parameters of step S13 are: the pressure in the chemical machine is ≥ 0.3Mpa, the temperature is ≥ 135°C, and the chemical time is > 30 min; the material is thoroughly disinfected and sterilized under high temperature and high pressure conditions; at the same time, under the action of spiral stirring, the material is dissolved into slag slurry, which is convenient for further disposal at the back end.

[0020] Furthermore, in step S24, the mixed slurry is heated to 65-75°C.

[0021] Furthermore, in step S25, the acidity of the anaerobic tank is not higher than 4500 mg / L, and the acid-base ratio is less than 0.4, and combined feeding can be performed.

[0022] Furthermore, in step S25, the temperature of the anaerobic tank is controlled at 55±0.5°C, which is more suitable for producing methanogens.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention combines the anaerobic process, and the residues after the harmless treatment of dead livestock and poultry and the kitchen waste are mixed with water and pulped respectively. By controlling the mixing ratio of the mixed slurry, the process requirements of the anaerobic digestion process on the carbon-nitrogen ratio of the material can be met, and anaerobic digestion can be carried out to solve the problem of difficult treatment of the residues of dead livestock and poultry; at the same time, the oil recovered by the degreasing treatment in the process and the biogas generated by the anaerobic digestion can be used as energy, realizing resource utilization and creating economic value.

[0025] 2. The present invention combines anaerobic technology to recover about 100 kg of fat for each ton of dead livestock and poultry treated; it can produce about 200 m³ of biogas for each ton of dead livestock and poultry treated; the residue is further reduced in volume, and after anaerobic digestion, the residue can be reduced by more than 85%. This achieves further reduction, resource utilization and harmless disposal of dead livestock and poultry. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments, but the embodiments of the present invention are not limited thereto.

[0028] See also Figure 1 , a method for combined anaerobic digestion of dead livestock and poultry residues and kitchen waste slurry, using the following process:

[0029] Crushing of dead livestock and poultry materials → Wet processing of dead livestock and poultry → Making pulp with water for residues → Mixing and homogenizing with food waste pulp → Degreasing of mixed pulp (oil is used to produce biodiesel) → The remaining mixed pulp enters the anaerobic tank for anaerobic digestion to produce biogas → Biogas purification and utilization.

[0030] The specific steps include:

[0031] (1) Wet treatment of dead livestock and poultry residues:

[0032] S11, feeding system: feeding dead livestock and poultry materials into the crushing system;

[0033] S12, Crushing system: crushing dead livestock and poultry materials;

[0034] S13, high temperature and high pressure chemical processing machine: the crushed dead poultry materials are added to the high temperature and high pressure chemical processing machine through the injection pump for high temperature and high pressure wet chemical processing; chemical processing process parameters: pressure in the chemical processing machine ≥ 0.3Mpa, temperature ≥ 135℃, chemical processing time > 30 min; the materials are thoroughly disinfected and sterilized under high temperature and high pressure conditions; at the same time, under the action of spiral stirring, the materials are dissolved into slag slurry, which is convenient for further disposal at the back end;

[0035] (2) Combined anaerobic digestion process:

[0036] S21, discharging screw: transports the residue after chemical treatment to the mixing tank;

[0037] S22, mixing tank: mix the residue after chemical treatment with water and mix them evenly to form residue slurry; the mass ratio of the slurry of dead livestock and poultry residue to the dead livestock and poultry material is: 2-2.5, and the measured TS must be less than 10%; (TS means "solid content", which refers to the percentage of solid content in a mixture. It is mainly used here to judge the content of organic matter in the slurry, because the solids in this slurry are almost all organic matter)

[0038] S23, pulping machine: the slag pulp enters the pulping machine for further crushing and pulping, and is evenly mixed with the food waste pulp in proportion; the mass ratio of dead livestock and poultry pulp to the mixed pulp is less than 7.5%; the mass ratio of food waste pulp to food waste is 1-1.1, and the measured TS is about 10%;

[0039] S24, horizontal separation oil removal: the mixed slurry enters the oil removal system to separate the oil; specific steps: the mixed slurry is heated to 65-75°C, enters the horizontal centrifuge to separate the oil phase, and the oil phase enters the butterfly centrifuge to further remove slag and water to obtain animal and plant mixed oil with a purity greater than 97%; the obtained oil is used to produce biodiesel;

[0040] S25, anaerobic tank: the mixed slurry after oil removal enters the anaerobic tank for anaerobic digestion to produce biogas, and the generated biogas is recycled. The acidity of the anaerobic tank is not higher than 4500mg / L, and the acid-base ratio is less than 0.4, and combined feeding can be carried out; the temperature is controlled to be 55±0.5℃, which is more suitable for methanogens;

[0041] S26. Finally, the produced biogas is purified and recycled.

[0042] Example 1

[0043] A method for combined anaerobic digestion of dead livestock and poultry residues and kitchen waste slurry, the specific steps comprising:

[0044] (1) Wet treatment of dead livestock and poultry residues:

[0045] S11, feeding system: feeding dead livestock and poultry materials into the crushing system;

[0046] S12, Crushing system: crushing dead livestock and poultry materials;

[0047] S13, high temperature and high pressure chemical processing machine: the crushed dead poultry materials are added to the high temperature and high pressure chemical processing machine through the injection pump for high temperature and high pressure wet chemical processing; chemical processing process parameters: the pressure in the chemical processing machine is 0.3Mpa, the temperature is 135℃, and the chemical processing time is 35min; the materials are thoroughly disinfected and sterilized under high temperature and high pressure conditions; at the same time, under the action of spiral stirring, the materials are dissolved into slag slurry, which is convenient for further disposal at the back end;

[0048] (2) Combined anaerobic digestion process:

[0049] S21, discharging screw: transports the residue after chemical treatment to the mixing tank;

[0050] S22, stirring tank: adding water to the residue after chemical treatment and stirring evenly to form residue slurry; wherein the mass ratio of the slurry amount of the dead livestock and poultry residue to the mass of the dead livestock and poultry material is 2:1;

[0051] S23, pulping machine: the slag pulp enters the pulping machine for further crushing and pulping, and is evenly mixed with the food waste pulp in proportion; the mass ratio of dead livestock and poultry pulp to the mixed pulp is 6.5%; the mass ratio of food waste pulping volume to food waste volume is 1:1; the measured TS is about 10%;

[0052] S24, horizontal separation oil removal: the mixed slurry enters the oil removal system to separate the oil; specific steps: the mixed slurry is heated to 65°C, enters the horizontal centrifuge to separate the oil phase, and the oil phase enters the butterfly centrifuge to further remove slag and water to obtain animal and plant mixed oil with a purity greater than 97%; the obtained oil is used to produce biodiesel;

[0053] S25, anaerobic tank: the mixed slurry after oil removal enters the anaerobic tank for anaerobic digestion to produce biogas, and the generated biogas is recycled. The acidity of the anaerobic tank is 4400mg / L, and the acid-base ratio is 0.3, and combined feeding can be carried out; the temperature is controlled to be 55±0.5℃, which is more suitable for methanogens;

[0054] S26. Finally, the produced biogas is purified and recycled.

[0055] Example 2

[0056] A method for combined anaerobic digestion of dead livestock and poultry residues and kitchen waste slurry, the specific steps comprising:

[0057] (1) Wet treatment of dead livestock and poultry residues:

[0058] S11 feeding system: feeding dead livestock and poultry materials into the crushing system;

[0059] S12, Crushing system: crushing dead livestock and poultry materials;

[0060] S13, high temperature and high pressure chemical processing machine: the crushed dead poultry materials are added to the high temperature and high pressure chemical processing machine through the injection pump for high temperature and high pressure wet chemical processing; chemical processing process parameters: the pressure in the chemical processing machine is 5Mpa, the temperature is 200℃, and the chemical processing time is 60min; the materials are thoroughly disinfected and sterilized under high temperature and high pressure conditions; at the same time, under the action of spiral stirring, the materials are dissolved into slag slurry, which is convenient for further disposal at the back end;

[0061] (2) Combined anaerobic digestion process:

[0062] S21, discharging screw: transports the residue after chemical treatment to the mixing tank;

[0063] S22, stirring tank: adding water to the residue after chemical treatment and stirring evenly to form residue slurry; wherein the mass ratio of the slurry amount of the dead livestock and poultry residue to the mass of the dead livestock and poultry material is 2.2:1;

[0064] S23, pulping machine: the slag pulp enters the pulping machine for further crushing and pulping, and is mixed evenly with the food waste pulp in proportion; the mass ratio of the dead livestock and poultry pulp to the mixed pulp is 7%; the mass ratio of the food waste pulp to the food waste is 1.1:1;

[0065] S24, horizontal separation oil removal: the mixed slurry enters the oil removal system to separate the oil; specific steps: the mixed slurry is heated to 70°C, enters the horizontal centrifuge to separate the oil phase, and the oil phase enters the butterfly centrifuge to further remove slag and water to obtain animal and plant mixed oil with a purity greater than 97%; the obtained oil is used to produce biodiesel;

[0066] S25, anaerobic tank: the mixed slurry after oil removal enters the anaerobic tank for anaerobic digestion to produce biogas, and the generated biogas is recycled. The acidity of the anaerobic tank is 4400mg / L, and the acid-base ratio is 0.3, and combined feeding can be carried out; the temperature is controlled to be 55±0.5℃, which is more suitable for methanogens;

[0067] S26. Finally, the produced biogas is purified and recycled.

[0068] Example 3

[0069] A method for combined anaerobic digestion of dead livestock and poultry residues and kitchen waste slurry, the specific steps comprising:

[0070] (1) Wet treatment of dead livestock and poultry residues:

[0071] S11 feeding system: feeding dead livestock and poultry materials into the crushing system;

[0072] S12, Crushing system: crushing dead livestock and poultry materials;

[0073] S13, high temperature and high pressure chemical processing machine: the crushed dead poultry materials are added to the high temperature and high pressure chemical processing machine through the injection pump for high temperature and high pressure wet chemical processing; chemical processing process parameters: the pressure in the chemical processing machine is 5Mpa, the temperature is 200℃, and the chemical processing time is 60min; the materials are thoroughly disinfected and sterilized under high temperature and high pressure conditions; at the same time, under the action of spiral stirring, the materials are dissolved into slag slurry, which is convenient for further disposal at the back end;

[0074] (2) Combined anaerobic digestion process:

[0075] S21, discharging screw: transports the residue after chemical treatment to the mixing tank;

[0076] S22, stirring tank: adding water to the residue after chemical treatment and stirring evenly to form residue slurry; wherein the mass ratio of the slurry amount of the dead livestock and poultry residue to the mass of the dead livestock and poultry material is 2.5:1;

[0077] S23, pulping machine: the slag pulp enters the pulping machine for further crushing and pulping, and is mixed evenly with the food waste pulp in proportion; the mass ratio of the dead livestock and poultry pulp to the mixed pulp is 7%; the mass ratio of the food waste pulp to the food waste is 1.1:1;

[0078] S24, horizontal separation oil removal: the mixed slurry enters the oil removal system to separate the oil; specific steps: the mixed slurry is heated to 75°C, enters the horizontal centrifuge to separate the oil phase, and the oil phase enters the butterfly centrifuge to further remove slag and water to obtain animal and plant mixed oil with a purity greater than 97%; the obtained oil is used to produce biodiesel;

[0079] S25, anaerobic tank: the mixed slurry after oil removal enters the anaerobic tank for anaerobic digestion to produce biogas, and the generated biogas is recycled. The acidity of the anaerobic tank is 4500mg / L, and the acid-base ratio is 0.35, and combined feeding can be performed; the temperature is controlled to be 55±0.5℃, which is more suitable for methanogens;

[0080] S26. Finally, the produced biogas is purified and recycled.

[0081] In 2021, the applicant adopted the combined anaerobic digestion method of the dead livestock and poultry residue and kitchen waste slurry of the present invention to dispose of 510 tons of dead livestock and poultry materials, 43,600 tons of kitchen waste, recover more than 2,000 tons of oil and fat, and produce 2.49 million cubic meters of biogas. At present, our company's combined anaerobic digestion process is operating normally. The reduction treatment and resource utilization of dead poultry have been successfully achieved, which has high application value and economic value.

[0082] The present invention adopts a wet process and anaerobic digestion process, and the residues after the wet process of dead livestock and poultry are mixed with water for pulping and kitchen waste slurry for uniform mixing, and after oil separation, combined with anaerobic fermentation, the residues are further reduced and resourced. Because the residues after the wet process of dead livestock and poultry are complex in composition, the organic nitrogen content is high, and the carbon-nitrogen ratio is low, it is not conducive to the anaerobic digestion process. The present invention utilizes the advantages of the joint construction and operation of the kitchen waste treatment and the harmless disposal of dead livestock and poultry projects, and combines the dead livestock and poultry chemical residues with the kitchen waste slurry for anaerobic digestion, and controls the mixing ratio of the mixed slurry, adjusts the carbon-nitrogen ratio of the mixed slurry, meets the carbon-nitrogen ratio requirement of the anaerobic digestion process, and effectively digests the mixed slurry for anaerobic digestion, and further realizes the reduction and resource utilization. The obtained oil can be used to produce biodiesel, and the biogas can also be recycled.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A method for combined anaerobic digestion of dead livestock and poultry residues and kitchen waste slurry, characterized in that: The following process is used: Crush dead livestock and poultry materials → wet chemical treatment of dead livestock and poultry → make pulp with water for chemical treatment residue → mix and homogenize with food waste slurry → remove oil from the mixed slurry, and use the obtained oil to produce biodiesel → the remaining mixed slurry enters the anaerobic tank for combined anaerobic digestion process to produce biogas → purify and utilize the biogas; Wherein, the method for wet processing of dead livestock and poultry includes: S11, feeding system: feeding dead livestock and poultry materials into the crushing system; S12, Crushing system: crushing dead livestock and poultry materials; S13, high temperature and high pressure chemical processing process: the crushed dead poultry materials are added to the high temperature and high pressure chemical processing machine through the injection pump for high temperature and high pressure wet chemical processing; The combined anaerobic digestion process comprises: S21, discharging screw: transports the residue after chemical treatment to the mixing tank; S22, stirring tank: adding water to the residue after chemical treatment and stirring evenly to form residue slurry; the mass ratio of the slurry amount of dead livestock and poultry residue to the mass of dead livestock and poultry material is 2-2.5; S23, pulping machine: the residue pulp enters the pulping machine for further crushing and pulping, and the obtained dead livestock and poultry residue pulp and restaurant kitchen waste pulp are fully and evenly mixed; wherein, the mass ratio of the dead livestock and poultry pulp to the mixed pulp is less than 7.5%; the mass ratio of the restaurant kitchen waste pulping amount to the restaurant kitchen waste amount is: 1-1.1; S24, horizontal separation oil removal: the mixed slurry enters the oil removal system to separate the oil; specific steps: the mixed slurry is heated and enters the horizontal centrifuge to separate the oil phase, and the oil phase enters the butterfly centrifuge to further remove slag and water to obtain animal and plant mixed oil with a purity greater than 97%; the obtained oil is used to produce biodiesel; S25, anaerobic tank: the mixed slurry after oil removal enters the anaerobic tank for anaerobic digestion to produce biogas, and the generated biogas is recycled; S26, finally purifying the obtained biogas and recycling it; The process parameters of the high temperature and high pressure chemical treatment in step S13 are: pressure in the chemical treatment machine ≥ 0.3 MPa, temperature ≥ 135° C., and chemical treatment time > 30 min.

2. The method for combined anaerobic digestion of dead livestock and poultry residues and kitchen waste slurry according to claim 1, characterized in that: In step S24, the mixed slurry is heated to 65-75°C.

3. The method for combined anaerobic digestion of dead livestock and poultry residues and kitchen waste slurry according to claim 1, characterized in that: In step S25, the acidity of the anaerobic tank is less than 4500 mg / L, and the acid-base ratio is less than 0.4, and combined feeding is performed.

4. The method for combined anaerobic digestion of dead livestock and poultry residues and kitchen waste slurry according to claim 1, characterized in that: In step S25, the temperature of the anaerobic tank is controlled at 55±0.5°C.

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