阅读说明：本技术 一种餐厨垃圾处理系统和处理方法 (Kitchen waste treatment system and treatment method ) 是由 张景新 崔毓轩 何义亮 于 2020-03-11 设计创作，主要内容包括：本发明公开了一种餐厨垃圾处理系统和处理方法,涉及固体废弃物资源化利用领域,包括预处理装置、消化装置和控温装置,其中,预处理装置包括餐厨垃圾分选设备、餐厨垃圾破碎设备、油水分离设备和储料罐；消化装置包括进料泵和高固体含量厌氧消化反应器；控温装置包括温度表、水泵和循环水箱。本发明的应用方法包括以下步骤：预处理餐厨垃圾；预处理后的餐厨垃圾与高固体含量(总固体含量>15％)的厌氧污泥和生物碳在高固体含量厌氧消化反应器内厌氧消化；收集沼气,排出沼渣。本发明改善了厌氧消化处理餐厨垃圾的产甲烷能力,提高了工艺稳定性,同时还得到含有生物炭的优质有机肥。(The invention discloses a kitchen waste treatment system and a treatment method, which relate to the field of solid waste resource utilization and comprise a pretreatment device, a digestion device and a temperature control device, wherein the pretreatment device comprises kitchen waste sorting equipment, kitchen waste crushing equipment, oil-water separation equipment and a storage tank; the digestion device comprises a feed pump and a high-solid content anaerobic digestion reactor; the temperature control device comprises a thermometer, a water pump and a circulating water tank. The application method of the invention comprises the following steps: pretreating kitchen waste; anaerobic digestion of the pretreated kitchen waste, anaerobic sludge with high solid content (total solid content is more than 15%) and biological carbon in a high solid content anaerobic digestion reactor; collecting the biogas and discharging biogas residues. The invention improves the methane production capability of anaerobic digestion treatment of the kitchen waste, improves the process stability and simultaneously obtains the high-quality organic fertilizer containing the biochar.)

1. A kitchen waste treatment system is characterized by comprising a pretreatment device, a digestion device and a temperature control device, wherein the pretreatment device comprises kitchen waste sorting equipment, kitchen waste crushing equipment, oil-water separation equipment and a storage tank; the digestion device comprises a feed pump, an outer-layer heating water jacket and a high-solid-content anaerobic digestion reactor, wherein the high-solid-content anaerobic digestion reactor is provided with a kitchen waste feed inlet, a methane discharge outlet and a methane residue discharge outlet; the temperature control device comprises a thermometer, a water pump and a circulating water tank; kitchen garbage sorting equipment with even have first pipeline between the kitchen garbage crushing equipment, kitchen garbage crushing equipment with even have the second pipeline between the oil water separating equipment, oil water separating equipment with even have the third pipeline between the storage tank, the storage tank with even have the fourth pipeline between the high solid content anaerobic digestion reactor with the charge pump, outer heating water jacket with even have the fifth pipeline between the circulation tank the thermometer and the water pump.

2. The kitchen waste treatment system of claim 1, wherein said high solids anaerobic digestion reactor is a horizontal cylindrical can structure with circular sides, and the ratio of the length of said can structure to the diameter of said circular sides is not less than 3.

3. The kitchen waste treatment system according to claim 2, wherein the biogas discharge port is provided at an upper portion of the first end of the canning structure, and the biogas residue discharge port is provided at a lower portion of the first end of the canning structure; and the upper part of the second end of the canned structure is provided with the kitchen waste feeding hole.

4. The kitchen waste treatment system according to claim 3, wherein said high-solid anaerobic digestion reactor is provided with said outer heating water jacket, and hot water is fed from said circulating water tank into said outer heating water jacket by said water pump; the water inlet of the outer-layer heating water jacket is arranged on the outer side of the first end of the canning structure, and the water outlet of the outer-layer heating water jacket is arranged on the outer side of the second end of the canning structure; and an eighth valve is arranged at the water inlet of the outer heating water jacket.

5. The kitchen waste treatment system according to claim 4, wherein a stirring paddle is arranged in the high-solid anaerobic digestion reactor, the stirring paddle is a double-helix stirring paddle, the rotating speed is not lower than 900rpm, and the stirring time is not less than 2 min/h.

6. The kitchen waste treatment system according to claim 5, wherein said first pipe is provided with a first valve; a second valve is arranged on the second pipeline; a third valve is arranged on the third pipeline; a fourth valve is arranged on the fourth pipeline; a ninth valve and the thermometer are arranged on the fifth pipeline; a tenth valve is arranged at the kitchen waste feeding hole, and a seventh valve is arranged at the biogas residue discharging hole; and a fifth valve and a pressure gauge are arranged at the methane discharge port.

7. The application method of the kitchen waste treatment system according to any one of claims 1 to 6, characterized in that the method comprises the following steps:

step 1, pretreating kitchen waste, wherein the process is as follows: the kitchen waste is sorted in the kitchen waste sorting equipment, enters the kitchen waste crushing equipment through the first pipeline for crushing, enters the oil-water separation equipment through the second pipeline for separation, and enters the storage tank through the third pipeline for temporary storage;

step 2, anaerobic digestion, comprising the following steps: the kitchen waste after pretreatment passes through the fourth pipeline and is sent into the high-solid-content anaerobic digestion reactor by the feed pump, and anaerobic digestion is carried out on the kitchen waste, anaerobic sludge and biochar in the high-solid-content anaerobic digestion reactor;

step 3, taking materials, wherein the process is as follows: collecting biogas from the biogas discharge port, and discharging biogas residues and biogas slurry from the biogas residue discharge port.

8. The method according to claim 7, wherein in the step 2, the pretreated kitchen waste is a main material, and the main material is put into the kitchen waste every day; the total solid content of the anaerobic sludge is more than 15 percent, the anaerobic sludge is used as an inoculum, the biochar is an auxiliary material, and the inoculum and the auxiliary material are added at one time.

9. The method according to claim 8, wherein the mass of the biogas residues and biogas slurry taken out every day in the step 3 is equal to the mass of the kitchen waste put in every day.

10. The method of claim 9, wherein the reaction conditions of the anaerobic digestion of step 2 are: the working temperature range is 30-40 ℃, the pH value in the high-solid-content anaerobic digestion reactor is not lower than 7.0, and nitrogen is introduced into the high-solid-content anaerobic digestion reactor for not less than 5 minutes after feeding and taking materials are finished every day.

Technical Field

The invention relates to the field of resource utilization of solid wastes, in particular to a kitchen waste treatment system and a kitchen waste treatment method.

Background

The Food and Agricultural Organization (FAO) of the united nations defines kitchen waste as a healthy edible substance that is wasted, discarded and decomposed at any stage in the food supply chain. The kitchen waste in different areas has different components due to the influence of factors such as dietary structure, living habits and the like, but mainly comprises starch, protein, plant fiber, animal fat and the like, and has higher organic matter concentration and biodegradability. Kitchen waste typically has a high water content (75-90%), a high volatile solids content (80-90%) and acidity (pH 4.4-5.8).

With the rapid development of economy in China, the catering industry is rapidly developed, however, the generated kitchen waste is also the key point for treating organic waste at present. For example, the daily kitchen waste production in Shanghai city is about 1000-1200 tons at present. At present, the treatment modes of the kitchen waste mainly comprise incineration, landfill, aerobic composting, anaerobic digestion and the like.

Anaerobic digestion is a good kitchen waste treatment technology because it facilitates the resource utilization of organic wastes. Anaerobic digestion treatment of kitchen waste refers to that under a specific environment, organic matters are decomposed by anaerobic and facultative microorganisms, hydrogen, carbon and oxygen are converted into methane mainly composed of methane and carbon dioxide, and elements such as nitrogen, phosphorus, potassium and the like are retained in biogas residues and biogas slurry.

However, in the anaerobic digestion process of kitchen waste with high solid content (total solid content > 15%) under high organic load, the problems of low methane yield, unstable process and the like are caused by the rapid accumulation of volatile organic acid, and the anaerobic digestion is difficult to be effectively carried out.

Therefore, those skilled in the art are devoted to develop a method and a system for treating kitchen waste, which can effectively treat kitchen waste with high solid content, improve methane yield and improve process stability.

Disclosure of Invention

In view of the above defects in the prior art, the technical problem to be solved by the present invention is to improve the anaerobic digestion treatment technology of the kitchen waste, improve the methane production capability of the kitchen waste and improve the process stability of the kitchen waste aiming at the anaerobic digestion of the kitchen waste with high solid content.

In order to achieve the purpose, the invention provides a system and a method for treating kitchen waste based on the principle of biochar-enhanced anaerobic digestion with high solid content. When the kitchen waste is subjected to anaerobic digestion treatment with high solid content (total solid content is more than 15%), biochar is added as an auxiliary material, the methane production capacity can be effectively improved, the stability of the process is improved, and meanwhile, high-yield methane and high-quality organic fertilizer containing biochar are obtained.

The invention provides a kitchen waste treatment system which comprises a pretreatment device, a digestion device and a temperature control device, wherein the pretreatment device comprises kitchen waste sorting equipment, kitchen waste crushing equipment, oil-water separation equipment and a storage tank; the digestion device comprises a feed pump, an outer-layer heating water jacket and a high-solid-content anaerobic digestion reactor, wherein the high-solid-content anaerobic digestion reactor is provided with a kitchen waste feed inlet, a methane discharge outlet and a methane residue discharge outlet; the temperature control device comprises a thermometer, a water pump and a circulating water tank; even there is first pipeline between kitchen garbage sorting facilities and the kitchen garbage crushing apparatus, kitchen garbage crushing apparatus with even there is the second pipeline between the oil water separating equipment, oil water separating equipment with even there is the third pipeline between the storage tank, the storage tank with even have the fourth pipeline between the high solid content anaerobic digestion reactor with the charge pump, even have the fifth pipeline between outer heating water jacket and the circulating water tank the thermometer table the water pump.

Further, the high-solid anaerobic digestion reactor is a horizontal cylindrical canning structure, two sides of the canning structure are circular, and the diameter ratio of the length of the canning structure to the diameter of the circular side face is not less than 3.

Furthermore, the first end of the canning structure is provided with the methane discharge port at the upper part and the biogas residue discharge port at the lower part; and the upper part of the second end of the canned structure is provided with the kitchen waste feeding hole.

Furthermore, the high-solid-content anaerobic digestion reactor is provided with the outer heating water jacket, and hot water enters the outer heating water jacket from the circulating water tank through the water pump; the water inlet of the outer-layer heating water jacket is arranged on the outer side of the first end of the canning structure, and the water outlet of the outer-layer heating water jacket is arranged on the outer side of the second end of the canning structure; and an eighth valve is arranged at the water inlet of the outer heating water jacket.

Further, a stirring paddle is arranged in the high-solid-content anaerobic digestion reactor, the stirring paddle is a double-helix stirring paddle, the rotating speed is not lower than 900rpm, and the stirring time is not less than 2 min/h.

Furthermore, a first valve is arranged on the first pipeline; a second valve is arranged on the second pipeline; a third valve is arranged on the pipeline; a fourth valve is arranged on the fourth pipeline; a ninth valve and the thermometer are arranged on the fifth pipeline; a tenth valve is arranged at the kitchen waste feeding hole, and a seventh valve is arranged at the biogas residue discharging hole; and a fifth valve and a pressure gauge are arranged at the methane discharge port.

The invention also provides an application method based on the kitchen waste treatment system, which comprises the following steps:

step 1, pretreating kitchen waste, wherein the process is as follows: the kitchen waste is sorted in the kitchen waste sorting equipment, enters the kitchen waste crushing equipment through the first pipeline for crushing, enters the oil-water separation equipment through the second pipeline for separation, and enters the storage tank through the third pipeline for temporary storage;

step 2, anaerobic digestion, comprising the following steps: the kitchen waste after pretreatment passes through the fourth pipeline and is sent into the high-solid-content anaerobic digestion reactor by the feed pump, and anaerobic digestion is carried out on the kitchen waste, anaerobic sludge and biochar in the high-solid-content anaerobic digestion reactor;

step 3, taking materials, wherein the process is as follows: collecting biogas from the biogas discharge port, and discharging biogas residues and biogas slurry from the biogas residue discharge port.

Further, in the step 2, in the high-solid anaerobic digestion reactor, the pretreated kitchen waste is a main material, and the main material is added every day; the total solid content of the anaerobic sludge is more than 15 percent, the anaerobic sludge is used as an inoculum, the biochar is an auxiliary material, and the inoculum and the auxiliary material are added at one time.

Further, the mass of the biogas residues and the biogas slurry taken out every day in the step 3 is equal to the mass of the kitchen waste put in every day.

Further, the reaction conditions of the anaerobic digestion of step 2 are: the working temperature range is 30-40 ℃, the pH value in the reactor is not lower than 7.0, and nitrogen gas with not less than 5 minutes is introduced into the anaerobic digestion reactor with high solid content after the feeding and taking of materials are finished every day.

The invention provides a kitchen waste treatment system and a treatment method, which have the following technical effects:

1. the biochar is alkaline due to surface metal elements (calcium, magnesium, potassium and the like) and functional groups (hydroxyl, carbon-carbon triple bond, amino and the like), and the kitchen waste is acidic (pH is 4.4-5.8), so that the buffering capacity of an anaerobic digestion system can be improved to a certain extent, and the activity of methanogenic flora is improved;

2. when the kitchen waste is subjected to anaerobic digestion treatment with high solid content (the total solid content is more than 15%), carbon-nitrogen ratio is usually low, and biochar is added as an auxiliary material, so that the carbon-nitrogen ratio of an anaerobic digestion system can be effectively adjusted, ammonia nitrogen inhibition is reduced, and methanogenic flora activity is enhanced;

3. the biochar is used as an auxiliary medium for anaerobic digestion with high solid content (total solid content is more than 15%), and plays a role in providing growth sites for microorganisms due to rich pore structures, so that the activity of methanogenic flora is effectively enhanced;

4. the biochar can be used as a soil conditioner, and the biogas residue and biogas slurry obtained by anaerobic digestion can be subjected to post-treatment to obtain a high-quality organic fertilizer containing biochar.

The conception, the specific structure and the technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the objects, the features and the effects of the present invention.

Drawings

FIG. 1 is a system flow diagram of a preferred embodiment of the present invention;

fig. 2 is a graph showing the variation of methane production with time in the first kitchen waste treatment process and the second kitchen waste treatment process according to a preferred embodiment of the present invention.

1-kitchen waste sorting equipment; 2-kitchen waste crushing equipment; 3-oil-water separation equipment; 4-a material storage tank; 5-a feed pump; 6-high solids anaerobic digestion reactor; 7-double helix stirring paddle; 8-a pressure gauge; 9-temperature meter; 10-a water pump; 11-circulating water tank.

Detailed Description

The technical contents of the preferred embodiments of the present invention will be more clearly and easily understood by referring to the drawings attached to the specification. The present invention may be embodied in many different forms of embodiments and the scope of the invention is not limited to the embodiments set forth herein.

In the drawings, structurally identical elements are represented by like reference numerals, and structurally or functionally similar elements are represented by like reference numerals throughout the several views. The size and thickness of each component shown in the drawings are arbitrarily illustrated, and the present invention is not limited to the size and thickness of each component. The thickness of the components may be exaggerated where appropriate in the figures to improve clarity.

As shown in fig. 1, the kitchen waste treatment system of the invention comprises a pretreatment device, a digestion device and a temperature control device, wherein the pretreatment device comprises a kitchen waste sorting device 1, a kitchen waste crushing device 2, an oil-water separation device 3 and a storage tank 4; the digestion device comprises a feed pump 5 and a high-solid anaerobic digestion reactor 6; the temperature control device comprises a thermometer 9, a water pump 10 and a circulating water tank 11.

The kitchen waste is sorted in a kitchen waste sorting device 1, enters a kitchen waste crushing device 2 through a first pipeline for crushing, enters an oil-water separation device 3 through a second pipeline for separation, and enters a storage tank 4 through a third pipeline for temporary storage; then the sewage is sent into a high-solid anaerobic digestion reactor 6 by a feed pump 5 through a fourth pipeline, and is subjected to anaerobic digestion together with anaerobic sludge and biochar in the high-solid anaerobic digestion reactor 6.

The anaerobic digestion reactor 6 with high solid content is a horizontal cylindrical canning structure, the two sides of the reactor are circular, the diameter ratio of the long side face to the circular side face is not less than 3, the upper part of the first end is provided with a methane discharge port, a fifth valve and a pressure gauge 8 are arranged, the lower part of the first end is provided with a methane residue discharge port, and the upper part of the second end of the canning structure is provided with a kitchen waste feed port which is connected with a feed pump 5 through a fourth pipeline; the high-solid content anaerobic digestion reactor 6 is provided with an outer-layer heating water jacket, hot water enters the outer-layer heating water jacket from a circulating water tank 11 through a water pump 10, the inner part of the high-solid content anaerobic digestion reactor 6 is guaranteed to reach a proper reaction temperature of 30-40 ℃, a water inlet of the outer-layer heating water jacket is arranged on the outer side of the first end of the canning structure, a water outlet of the outer-layer heating water jacket is arranged on the outer side of the second end of the canning structure, an eighth valve is arranged on a pipeline of the water inlet of the outer-layer heating water jacket, and a; the double-helix stirring paddle 7 is arranged in the anaerobic digestion reactor 6 with high solid content, the rotating speed is not lower than 900rpm, and the stirring time is not less than 2 min/h.

Anaerobic sludge with high solid content (total solid content is more than 15 percent) as inoculum and biochar as auxiliary materials are put into the high solid content anaerobic digestion reactor 6 at one time, and anaerobic digestion is carried out in the high solid content anaerobic digestion reactor 6 together with the pretreated kitchen waste fed every day; collecting biogas from a biogas discharge port every day, and discharging biogas residues and biogas slurry from a biogas residue discharge port. In order to maintain material balance, the mass of the biogas residues and the biogas slurry taken out every day is equal to the mass of the kitchen waste put in every day.

After feeding and taking materials every day, nitrogen gas is introduced into the high-solid-content anaerobic digestion reactor 6 for not less than 5 minutes so as to maintain the anaerobic environment in the high-solid-content anaerobic digestion reactor 6.

The added auxiliary material biochar is alkaline due to surface metal elements (calcium, magnesium, potassium and the like) and functional groups (hydroxyl, carbon-carbon triple bond, amino and the like), the kitchen waste is acidic (pH is 4.4-5.8), the proportion of the biochar serving as the auxiliary material in the high-solid-content anaerobic digestion reactor 6 and the main material and the treated kitchen waste can adjust the pH value in the reactor to a certain degree, so that the pH value is easy to reach more than 7.0; when the kitchen waste is subjected to anaerobic digestion treatment with high solid content (the total solid content is more than 15%), carbon-nitrogen ratio is usually low, and biochar is added as an auxiliary material, so that the carbon-nitrogen ratio of an anaerobic digestion system can be effectively adjusted, ammonia nitrogen inhibition is reduced, and methanogenic flora activity is enhanced; the biochar is used as an auxiliary medium for anaerobic digestion with high solid content (total solid content is more than 15%), and plays a role in providing growth sites for microorganisms due to rich pore structures, so that the activity of methanogenic flora is effectively enhanced; the biochar can be used as a soil conditioner, and the biogas residue and biogas slurry obtained by anaerobic digestion can be subjected to post-treatment to obtain a high-quality organic fertilizer containing biochar.

In the preferred embodiment of the present invention, under the condition that the anaerobic digestion main material and the inoculum are the same, the first kitchen waste treatment process without adding the biochar and the second kitchen waste treatment process with adding the biochar are respectively carried out in the same high-solid anaerobic digestion reactor 6 under the same feeding and taking operation mode and reaction conditions.

The main materials are as follows: the kitchen waste has a total solid content of 23.5% (water content is 76.5% w/w) and a volatile solid content of 21.2%; the inoculum was anaerobic sludge with a total solids content of 18.9% (water content 81.1% w/w) and a volatile solids content of 11.7%.

The working volume of the high solids anaerobic digestion reactor 6 was 3L.

The feeding mode is as follows: 3000g of anaerobic sludge is added into a reactor, and 80g of kitchen waste is fed every day.

Wherein the digestion reactor of the first kitchen waste treatment process is not added with biochar; 40g of biochar is added into a digestion reactor in the second kitchen waste treatment process as an auxiliary material.

The material taking mode is as follows: the operation is carried out in a mode of taking 80g of biogas residues and biogas slurry every day, namely the mass of the taken biogas residues and biogas slurry is the same as that of the added kitchen waste, and the operation is continuously carried out for 6 days.

Reaction conditions are as follows: a. after the feeding and taking of materials of the anaerobic digestion reactor 6 with high solid content are finished each time, introducing nitrogen into the reactor for five minutes to ensure the anaerobic environment of the reactor;

b. the temperature of the circulating water tank 11 is continuously controlled to be 35 ℃, circulating water is led into the external water jacket by a water pump 10, and the temperature in the reactor is not lower than 30 ℃;

c. the pH of the high solids anaerobic digestion reactor 6 is not less than 7.0;

d. the rotation speed of the double helix stirring paddle 7 is 900rpm, and the stirring time is 2 min/h.

And (3) detection results:

a first kitchen waste treatment process: the total gas yield is 79652ml, the total methane yield is 37830ml, the methane yield is 370.9ml CH4/gVS-FW (namely the amount of methane produced by kitchen waste per g of volatile solid), and the average methane concentration is 47.49%.

And a second kitchen waste treatment process: the total gas yield is 92092ml, the total methane yield is 44029ml, the methane yield is 431.7ml CH4/gVS-FW (namely the amount of methane produced by kitchen waste per g of volatile solid), and the average methane concentration is 47.81%.

As shown in fig. 2, the lower curve in the graph represents the variation of the accumulated methane yield with time in the first kitchen waste treatment process, and the upper curve represents the variation of the accumulated methane yield with time in the second kitchen waste treatment process. It can be seen from the figure that the daily cumulative methane yield in the second kitchen waste treatment process is higher than that in the first kitchen waste treatment process, and the difference between the two increases with the increase of digestion time. The method has the advantages that the auxiliary material biochar added in the second kitchen waste treatment process improves the total output of methane, the methane output rate of unit kitchen waste, effectively solves the problems of low methane yield, unstable process and the like caused by rapid accumulation of volatile organic acid, improves the methane output, and obtains biogas residues containing biochar which is a high-quality organic fertilizer.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.