WO2023024713A1

WO2023024713A1 - System and method for cooperative treatment of garden waste and kitchen waste

Info

Publication number: WO2023024713A1
Application number: PCT/CN2022/103751
Authority: WO
Inventors: 宫建瑞; 王瑾瑾; 刘杰; 徐学骁; 朱菁; 李康杰; 袁建海
Original assignee: 南京万德斯环保科技股份有限公司
Priority date: 2021-08-25
Filing date: 2022-07-04
Publication date: 2023-03-02
Also published as: CN113680798A

Abstract

A system and method for the cooperative treatment of garden waste and kitchen waste. The system comprises a kitchen waste pretreatment system, a garden waste pretreatment system, a mixed inoculation system, a dry anaerobic system and a solid-liquid separation system. The degradation of lignocellulose in garden waste is accelerated by means of a multi-stage mechanical crushing - acetic acid - laccase pretreatment process for the garden waste; moreover, by means of returning a biogas slurry back for inoculation, the anaerobic time is shortened and the biogas yield is increased; and the C/N ratio and the solid content of materials are adjusted by means of recycling biogas residue, such that the problem of material fluctuation of garden waste due to seasonal pruning is effectively solved, and the stability of the system is maintained.

Description

A system and method for collaborative processing of garden waste and kitchen waste

technical field

The invention belongs to the technical field of anaerobic fermentation of organic solid waste, and in particular relates to a system and method for co-processing garden waste and kitchen waste.

Background technique

With the advancement of waste classification and the gradual improvement of the classification level, there are more and more examples of organic solid waste anaerobic fermentation biogas projects. Common organic solid waste includes: kitchen waste, garden waste, fruit and vegetable waste, livestock and poultry manure And crop straw, etc., after anaerobic fermentation, organic solid waste will produce biogas bioenergy, which can effectively alleviate the contradiction between energy supply and demand and improve the energy structure. Therefore, the anaerobic fermentation biogas project is an important way of resource utilization of organic solid waste.

There are two main methods of anaerobic fermentation of organic solid waste, wet anaerobic and dry anaerobic. Wet anaerobic is suitable for organic solid waste with a solid content of 8%-15%. It is widely used in engineering, but it has high requirements for pretreatment capacity, slurry quality, sand and impurity content, and is sensitive to load impact. Dry anaerobic is suitable for organic solid waste with high solid content (15%-40%). It has strong load impact resistance and low requirements for material pretreatment, but the investment cost of dry anaerobic equipment is relatively high.

Affected by economic level, dietary structure, garbage classification level and supporting facilities construction, there are certain differences in the kitchen waste collected and transported in different regions, but the overall solid content of kitchen waste is relatively high at 15%-35%, C/ The N ratio is 15-30. Due to the high solid content of kitchen waste, if the wet anaerobic method is used, a large amount of water is required to reduce the solid content, but it will increase the amount of biogas slurry treatment and cause waste of water resources. Therefore, the dry anaerobic method is used to ferment high-solid kitchen waste. leftover garbage. Garden waste has the characteristics of rich carbon, low nitrogen, and high solid content (TS 40%-60%), especially the C/N ratio of plant branches is as high as 56.5, and garden waste is usually collected by landfill, incineration, pyrolysis, composting and aeration. Oxygen fermentation and other treatment methods, landfill and incineration methods will cause environmental pollution and resource waste, pyrolysis method is easy to produce secondary pollution, and composting method can turn garden waste resources into organic fertilizers, but there are problems such as long time to fully decompose, poor fertilizer efficiency, and organic fertilizers. Therefore, a dry anaerobic system that tolerates high-solid materials can be used to treat garden waste.

The collaborative treatment of kitchen waste and garden waste can not only adjust the solid content and C/N ratio of materials, effectively solve the system instability problems caused by material fluctuations and accumulation of volatile fatty acids, but also significantly improve anaerobic digestion efficiency and biogas production . The patent number is: CN201810140063.5, and the patent name is: a co-processing method of kitchen waste and green waste, using two-phase wet anaerobic method to treat kitchen waste and green waste generated in residential areas, but due to the high solid Containing characteristics, when pulping, it is necessary to add water with a mass ratio of 1:1-3:1 to kitchen waste for dilution, to increase unnecessary water use and biogas slurry treatment, and to use ultrasonic and high-temperature heat-humidity treatment at the same time Garden waste, equipment input and operating costs are high.

Contents of the invention

The purpose of the present invention is to provide a system and method for the coordinated treatment of garden waste and kitchen waste, which realizes the collaborative resource utilization of kitchen waste and garden waste through dry anaerobic, green, efficient and stable, and effectively avoids the impact of material fluctuations. risk of instability.

In order to solve the above problems, the scheme adopted by the present invention is as follows:

A system for the coordinated treatment of garden waste and kitchen waste of the present invention includes a pretreatment system and an anaerobic system;

The pretreatment system includes a kitchen waste pretreatment system and a garden waste pretreatment system;

The kitchen waste pretreatment system is used to sequentially crush, magnetically separate and screen the kitchen waste,

The garden waste pretreatment is used to sequentially perform multi-stage mechanical crushing, acetic acid pretreatment, and laccase joint pretreatment on the garden waste;

The anaerobic system includes a mixed inoculation system, a dry anaerobic system and a solid-liquid separation system;

The mixed inoculation system is used to mix the kitchen waste slurry and the garden garbage slurry treated by the pretreatment system, and heat the kitchen waste slurry and the garden garbage slurry, and adjust the TS range and C/N of the mixed slurry scope;

The slurry treated by the mixed inoculation system is pumped into the dry anaerobic system to ferment the slurry, and the fermented slurry enters the solid-liquid separation system, which is used to separate the slurry into biogas residue and biogas liquid.

Further, the solid-liquid separation system is also used to return part of the biogas slurry to the mixed inoculation system. When the output of garden waste raw materials is insufficient or fluctuates greatly, the solid-liquid separation system is also used to reuse the biogas residue to the mixed inoculation system.

Further, heating equipment is also provided in the mixed inoculation system for heating the mixed slurry.

A method for coordinating treatment of garden waste and kitchen waste according to the present invention comprises the following steps:

Step 1: Kitchen waste and garden waste are collected and transported separately and enter the pretreatment system, kitchen waste enters the kitchen waste pretreatment system, and garden waste enters the garden waste pretreatment system;

Step 2, sequentially crushing, magnetically separating and screening the kitchen waste in the kitchen waste pretreatment system;

After the pretreatment of the kitchen waste, large pieces of plastic, paper, metal and other impurities in the kitchen waste are screened out, and the kitchen waste is crushed into a slurry with a particle size of ≤80mm.

Step 3, performing multi-stage mechanical crushing, acetic acid pretreatment, and laccase combined pretreatment on the garden waste in the garden waste pretreatment system;

After multi-stage crushing, the particle size of garden waste is ≤80mm, and then at 25-30°C, add acetic acid with a concentration of 15%-30%, adjust the solid-liquid ratio to 1:10-1:20, and soak the garden waste for 4-24 hours Enter laccase pretreatment, add industrial grade laccase to the slurry at a ratio of 0.01-0.5‰ at a temperature of 30-35°C, control the pH to 4.5-6.0, and treat for 6-48h.

Step 4, the pretreated kitchen waste and garden waste slurry enters the mixed inoculation system at a ratio of 2:1-6:1, and the slurry is fully mixed under mechanical stirring; the speed of mechanical stirring is 10-30r/min; , using biogas slurry for inoculation, and the mixed slurry is heated to 25-35°C in the mixed inoculation system.

Step 5. After 2-12 hours of mixed inoculation, the slurry is pumped into the dry anaerobic system and fermented in the dry anaerobic system. The fermentation time is 27-30 days. After fermentation, the material enters the solid-liquid separation system, It is separated into biogas residue and biogas slurry.

Step 6: Part of the biogas slurry is returned to the mixed inoculation system, the biogas slurry backflow inoculation ratio is 30%-50%, and the biogas slurry backflow interval is 2-12h.

Furthermore, due to the influence of seasonal pruning, the amount of garden waste produced during spring and autumn pruning is more, and the solid content of litter in autumn and winter is higher. Therefore, there are seasonal fluctuations in the output and nature of garden waste. When the amount of garden waste is insufficient due to seasonal pruning, part of the biogas residue is reused in the mixed inoculation system. The ratio of kitchen waste to biogas residue reuse is 2:1-6:1, and the interval between biogas residue reuse is 2-12h.

Beneficial effect:

(1) The multi-stage mechanical crushing-acetic acid-laccase combined pretreatment method of garden waste provided by the present invention can accelerate the degradation of lignocellulose in garden waste, inoculate through biogas slurry backflow, shorten the fermentation cycle, and increase biogas production.

(2) The system for collaborative processing of garden waste and kitchen waste of the present invention can effectively avoid the stratification of kitchen waste in the dry anaerobic system, adjust the C/N ratio and solid content of raw materials, and improve the operation of the dry anaerobic system Stability and gas production rate.

(3) The present invention adjusts the C/N ratio and solid content of the mixture of kitchen waste and garden waste by recycling biogas residues, effectively coping with the problem of material yield and property fluctuations caused by seasonal pruning of garden waste.

Description of drawings

In order to more clearly illustrate the specific implementation of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the specific implementation or description of the prior art. Obviously, the accompanying drawings in the following description The drawings show some implementations of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative work.

Fig. 1 is a flow chart of the system for co-processing garden waste and kitchen waste of the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Embodiment 1, a system for the coordinated treatment of garden waste and kitchen waste, as shown in Figure 1, includes a pretreatment system and an anaerobic system, and the pretreatment system includes a kitchen waste pretreatment system and a garden waste pretreatment system ;

Anaerobic systems include mixed inoculation systems, dry anaerobic systems and solid-liquid separation systems.

The kitchen waste pretreatment system crushes, magnetically separates and screens the kitchen waste in sequence. After the kitchen waste is pretreated, the material particle size is ≤80mm.

The garden waste pretreatment system adopts a multi-stage mechanical crushing-acetic acid-laccase combined pretreatment process. The garden waste is multi-stage mechanically crushed into particles with a particle size of ≤80mm, and then pretreated with 15%-30% concentration of acetic acid to control solid waste. Liquid ratio 1:10-1:20, soak garden waste at 25-30℃ for 4-24 hours, then enter laccase pretreatment, add industrial grade laccase to slurry at 0.01-0.5‰, control pH 4.5- 6.0, temperature 30-35℃, treatment time 6-48h.

After pretreatment, the kitchen waste and garden waste slurry are mixed and inoculated, the mixing ratio of the two is 2:1-6:1, the TS range of the mixed material is adjusted to 20%-40%, and the C/N is 25-30. The mixed inoculation system uses mechanical stirring to mix the materials, and the stirring rate is 10-30r/min. The mixed inoculation system is equipped with a heating system with a heating temperature of 25-35°C. The materials are mixed for 2-12 hours and then pumped into the dry anaerobic system. The biogas slurry after solid-liquid separation is partly returned to the mixed inoculation system, the biogas slurry reflux inoculation ratio is 30%-50%, and the biogas slurry reflux interval is 2-12h.

Affected by seasonal pruning, the amount of garden waste generated during pruning in spring and autumn is more, and the solid content of litter in autumn and winter is higher. Therefore, there are seasonal fluctuations in the output and nature of garden waste. When the amount of garden waste is insufficient due to seasonal pruning, part of the biogas residue is reused in the mixed inoculation system. The ratio of kitchen waste to biogas residue reuse is 2:1-6:1, and the interval between biogas residue reuse is 2-12h.

Embodiment 2: a kind of method for the cooperative processing of garden waste and kitchen waste of the present invention comprises the following steps:

Step 2: After the kitchen waste is crushed, magnetically separated, screened and other processes, large pieces of plastic, paper, metal and other impurities in the kitchen waste are screened out, and the kitchen waste is crushed into a slurry with a particle size of ≤ 80mm.

Step 3, the garden waste is firstly processed by multi-stage crushing and the particle size is ≤80mm, and then at a temperature of 25-30°C, add acetic acid with a concentration of 15%-30%, adjust the solid-liquid ratio to 1:10-1:20, and soak the garden waste After 4-24 hours, enter laccase pretreatment, add industrial grade laccase to the slurry at a rate of 0.01-0.5‰ at a temperature of 30-35°C, and control the pH to 4.5-6.0 for 6-48 hours.

Step 4, the pretreated kitchen waste and garden waste slurry enters the mixed inoculation system at a ratio of 2:1-6:1, and the slurry is fully mixed under mechanical stirring at 10-30r/min. At the same time, biogas slurry is used for inoculation, and the inoculum amount of the biogas slurry is 30%-50% of the mixed slurry, and the mixed slurry is heated to 25-35° C. in the mixed inoculation system.

Step 5: After 2-12 hours of mixed inoculation, the slurry is pumped into the dry anaerobic system. After 27-30 days of fermentation, the material enters the solid-liquid separation system and is separated into biogas residue and biogas slurry.

Embodiment 3: When the garden waste in summer is mainly grass and leaves, and the amount of collection and transportation is insufficient due to less pruning, at first the kitchen waste (TS about 15%, C/N ratio about 20) is crushed, magnetically separated and screened The treated slurry is pumped into the mixing inoculation system. Due to the low solid content and insufficient output of garden waste at this time, part of the biogas residue can be reused in the mixed inoculation system to supplement the shortage of garden waste. The ratio of biogas residue to the total amount of kitchen waste and garden waste is 1:5, and the solid content of the material is adjusted to 20%-30%, and the C/N is 25-30. Then return the biogas slurry for inoculation at the same time, and the inoculation ratio of biogas slurry to material is 30%. Mix and stir at 15r/min for 2h, heat the slurry to 30°C and pump it into the dry anaerobic system. After about 28 days of anaerobic fermentation, the material is separated into solid and liquid into biogas residue and biogas slurry, which can be further reused as a resource or treated to meet the discharge standards.

The present invention is not limited to the above-mentioned specific embodiments and application fields, and the above-mentioned specific embodiments are only illustrative and instructive, rather than restrictive. Under the enlightenment of this description, those skilled in the art can also make many forms without departing from the protection scope of the claims of the present invention, and these all belong to the protection of the present invention.

Claims

A system for co-processing garden waste and kitchen waste, characterized in that it includes a pretreatment system and an anaerobic system;

The pretreatment system includes a kitchen waste pretreatment system and a garden waste pretreatment system;

The kitchen waste pretreatment system is used to sequentially crush, magnetically separate and screen the kitchen waste,

The garden waste pretreatment is used to sequentially perform multi-stage mechanical crushing, acetic acid pretreatment, and laccase joint pretreatment on the garden waste;

The anaerobic system includes a mixed inoculation system, a dry anaerobic system and a solid-liquid separation system;

The mixed inoculation system is used to mix the kitchen waste slurry and the garden garbage slurry treated by the pretreatment system, and heat the kitchen waste slurry and the garden garbage slurry, and adjust the TS range and C/N of the mixed slurry scope;

The slurry treated by the mixed inoculation system is pumped into the dry anaerobic system to ferment the slurry, and the fermented slurry enters the solid-liquid separation system, which is used to separate the slurry into biogas residue and biogas liquid.
The system for co-processing garden waste and kitchen waste according to claim 1, wherein the solid-liquid separation system is also used to return part of the biogas slurry to the mixed inoculation system.
A system for co-processing garden waste and kitchen waste according to claim 1, characterized in that, when the output of garden waste raw materials is insufficient or fluctuates greatly, the solid-liquid separation system is also used to reuse biogas residues to Mixed inoculation system.
A method for co-processing garden waste and kitchen waste, characterized in that it comprises the following steps:

Step 1: Kitchen waste and garden waste are collected and transported separately and enter the pretreatment system, kitchen waste enters the kitchen waste pretreatment system, and garden waste enters the garden waste pretreatment system;

Step 2, sequentially crushing, magnetically separating and screening the kitchen waste in the kitchen waste pretreatment system;

Step 3, performing multi-stage mechanical crushing, acetic acid pretreatment, and laccase combined pretreatment on the garden waste in the garden waste pretreatment system;

Step 4, the pretreated kitchen waste and garden waste slurry enters the mixed inoculation system at a ratio of 2:1-6:1, and the slurry is fully mixed under mechanical stirring; at the same time, the biogas slurry is used for inoculation, and the mixed inoculation system The mixed slurry is heated to 25-35°C;

Step 5. After 2-12 hours of mixed inoculation, the slurry is pumped into the dry anaerobic system and fermented in the dry anaerobic system. After fermentation, the material enters the solid-liquid separation system and is separated into biogas residue and biogas liquid;

Step 6, part of the biogas slurry is refluxed to the mixed inoculation system, and the interval between biogas slurry reflux is 2-12 hours.
A method for co-processing garden waste and kitchen waste according to claim 4, characterized in that, after the kitchen waste is pretreated in step 2, large pieces of plastic, paper, and metal impurities in the kitchen waste are screened out, The kitchen waste is crushed into a slurry with a particle size of ≤80mm.
A method for co-processing garden waste and kitchen waste according to claim 4, characterized in that in step 3, the garden waste undergoes multi-stage crushing and has a particle size of ≤80mm, and then at a temperature of 25-30°C, a concentration of 15 %-30% acetic acid, adjust the solid-liquid ratio to 1:10-1:20, soak the garden waste for 4-24 hours, then enter the laccase pretreatment, and put industrial-grade laccase at a ratio of 0.01-0.5‰ at a temperature of 30-35°C Add it to the slurry, control the pH to 4.5-6.0, and treat for 6-48h.
The method for co-processing garden waste and kitchen waste according to claim 4, characterized in that the speed of mechanical stirring in step 4 is 10-30r/min.
The method for co-processing garden waste and kitchen waste according to claim 4, wherein the fermentation time in step 5 is 27-30 days.
The method for co-processing garden waste and kitchen waste according to claim 4, characterized in that in step 6, the biogas slurry reflux inoculation ratio is 30%-50%.
A method for co-processing garden waste and kitchen waste according to claim 4, further comprising the following steps: when the output of garden waste raw materials is insufficient or fluctuates greatly, the biogas residue is recycled to the mixed inoculation system, and the kitchen waste The mixing ratio of waste and biogas residue is 2:1-6:1, and the interval of biogas residue reuse is 2-12h.