Closed drying and fresh air fermentation combined type cow dung treatment system

Abstract

The application discloses a closed drying and fresh air fermentation combined type cow dung treatment system, which comprises a cow dung drying device and a cow dung fermentation device, the cow dung drying device is used for drying cow dung through hot air drying, and the wet hot air in the cow dung drying device is circulated through a closed drying system; the closed drying system comprises a dust removal device, a heat exchange device and a heat pump device; the heat exchange device is further connected with a fresh air circulation system, the fresh air circulation system comprises a fresh air supply device, a return air adjusting device and an exhaust air adjusting device; the cow dung fermentation device is used for fermenting cow dung by using fresh air treated through the fresh air circulation system. The cow dung treatment system fully utilizes the energy of each part, and maximally reduces energy input and consumption. The cow dung treated through the system can be used as bedding for cows, which can effectively reduce the incidence of mastitis of the cows and improve the milk yield of the cows.

Description

Technical Field

[0001] This invention relates to a closed-loop drying and fresh air fermentation combined cow manure treatment system, belonging to the field of livestock manure reuse. Background Technology

[0002] In today's large-scale dairy farming, the amount of cow manure produced is increasing daily, causing significant negative impacts on the ecological environment and human health. Reusing cow manure could alleviate these problems. Currently, there are three main directions for the reuse of cow manure: biogas feedstock, organic fertilizer, and cow bedding. However, using it as cow bedding requires drying, and existing drying methods have several issues. For example, patent application CN201710402253.5 discloses a process for drying cow manure for use as bedding, which uses combustion, requiring a large amount of fuel and generating exhaust gases during both combustion and drying processes. Patent application CN202120445878.1 discloses a device suitable for drying cow manure, but it fails to recycle air and consumes a lot of energy. Therefore, there is an urgent need to develop a low-energy-consumption system capable of large-scale cow manure drying. Summary of the Invention

[0003] Purpose of the invention: The purpose of this invention is to provide a closed-loop drying and fresh air fermentation combined cow manure treatment system.

[0004] Technical solution: The present invention provides a closed-loop drying and fresh air fermentation combined cow manure treatment system, wherein the cow manure treatment system includes cow manure drying equipment and cow manure fermentation equipment.

[0005] The cow dung drying equipment dries cow dung using hot air drying, and the hot and humid air inside is circulated through a closed drying system.

[0006] The closed-loop drying system includes a dust removal device, a heat exchange device, and a heat pump device;

[0007] The heat exchange device is also connected to a fresh air circulation system, which includes a fresh air supply device, a return air regulating device, and an exhaust air regulating device.

[0008] The cow dung fermentation equipment uses fresh air treated by a fresh air circulation system to ferment cow dung.

[0009] Furthermore, the circulation route of the hot and humid air in the cow dung drying equipment is as follows: first, it enters the dust removal device for dust removal, then enters the heat exchange device to exchange heat with the fresh air supplied from the fresh air supply device. After cooling and dehydration, it enters the heat pump device for dehydration and heating, becoming dry hot air, which can then re-enter the cow dung drying equipment.

[0010] Furthermore, the air temperature after cooling is 40–80°C, and the relative humidity is 100%–80%.

[0011] Furthermore, the air temperature after dehydration and heating is 70–100°C, and the relative humidity is 10%–1%.

[0012] Furthermore, the airflow path within the fresh air circulation system is as follows: fresh air is delivered into the heat exchange device through the fresh air supply device; after the fresh air and the dust-removed humid and hot air complete the heat exchange, part of it enters the cow manure fermentation equipment, part of it is discharged through the exhaust regulating device, and part of it returns to the fresh air supply device through the return air regulating device.

[0013] The present invention also provides a method for using the above system, comprising the following steps:

[0014] (1) Pre-treat the cow manure. The moisture content of the pre-treated cow manure is 55% to 65%.

[0015] (2) Put the cow manure into the cow manure drying equipment 1 for drying. After the moisture content is lower than 48%, it is put into the cow manure fermentation equipment 8.

[0016] (3) After 5 to 7 days of fresh air fermentation, cow manure can be obtained as qualified manure.

[0017] Furthermore, the pretreatment of cow manure in step (1) includes removing impurities and moisture from the cow manure.

[0018] Furthermore, the specific steps for the pretreatment of cow manure are as follows: remove impurities and other waste from the cow manure with an initial solid content of 5% to 10%, filter the cow manure mixture to retain the solid materials in the cow manure, and finally squeeze and dehydrate the solid materials.

[0019] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: This invention discloses a cow manure treatment system that uses a closed-loop drying process to dry both air and cow manure, followed by fresh air fermentation of the manure. This fully utilizes the energy of each component, minimizing energy input and consumption, and eliminating harmful gas emissions. The cow manure treated by this system has a moisture content below 45% and the content of harmful bacteria such as E. coli is below 100 MPN / g. Using this system as bedding material for cows can effectively reduce the incidence of mastitis in dairy cows and increase milk production. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the system of the present invention. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0022] Example 1

[0023] The present invention includes a cow dung drying device 1 and a cow dung fermentation device 8.

[0024] The cow dung drying equipment 1 dries cow dung by hot air drying, and the hot and humid air inside is circulated through a closed drying system.

[0025] The closed-loop drying system includes a dust removal device 2, a heat exchange device 3, and a heat pump device 4;

[0026] The humid and hot air in the cow dung drying equipment 1 first enters the dust removal device 2 for dust removal, and then enters the heat exchange device 3 to exchange heat with the fresh air supplied from the fresh air supply device 5 (in the heat exchange device, the humid and hot air and the fresh air are in two independent spaces and do not come into contact). After cooling and dehydration, it enters the heat pump device 4 (the air temperature after cooling is 40-80℃, and the relative humidity is 100%-80%). After dehydration and heating, it becomes dry hot air (the air temperature after dehydration and heating is 70-100℃, and the relative humidity is 10%-1%), and can then re-enter the cow dung drying equipment 1, and so on.

[0027] The heat exchange device 3 is also connected to a fresh air circulation system, which includes a fresh air supply device 5, a return air regulating device 6, and an exhaust air regulating device 7.

[0028] Fresh air is delivered into the heat exchanger 3 through the fresh air supply device 5. After the fresh air and the dust-removed humid air complete the heat exchange, part of it enters the cow manure fermentation equipment 8, part of it is discharged through the exhaust regulating device 7, and part of it returns to the fresh air supply device 5 through the return air regulating device 6 for circulation.

[0029] The cow dung fermentation equipment 8 uses fresh air treated by the fresh air circulation system to ferment cow dung, and excess fresh air is discharged from the cow dung fermentation equipment 8.

[0030] Compared to systems without fresh air heat exchange (excluding 3, 6, and 7), the energy consumption of the system in this application is reduced by approximately 9%.

[0031] Example 2

[0032] The initial cow manure in the manure pit, with a solid content of 5%–10%, undergoes pretreatment: impurities and other organic waste are removed from the manure, and the manure mixture is filtered to remove most of the water, retaining the solid material in the manure. The moisture content of the solid material is 70%–80%. Finally, the manure is squeezed to dehydrate it, and the moisture content of the solid material after pretreatment is 55%–65%.

[0033] The pretreated cow manure is placed in the cow manure drying equipment 1 and subjected to mass and heat transfer with the dry hot air delivered by the heat pump device 4. After the moisture content is lower than 48%, it is put into the cow manure fermentation equipment 8 for 5 to 7 days of fresh air fermentation treatment. The solid temperature of the fermented cow manure is 70℃-90℃, and the moisture content of the solid material is 40%-45%.

[0034] E. coli levels in cow manure before and after fermentation were tested. Before fermentation, the E. coli content in the cow manure was greater than 1000 MPN / g, while after fermentation it was less than 100 MPN / g. Using cow manure treated with the process described in this application as bedding material for cows can reduce the incidence of mastitis in dairy cows by at least 0.5%.

Claims

1. A closed drying and fresh air fermentation combined cow dung treatment system for making cow bedding litter, characterized in that, The cattle dung treatment system comprises a cattle dung drying device (1) and a cattle dung fermentation device (8), The cattle dung drying device (1) dries the cattle dung by hot air drying, and the wet hot air in the cattle dung drying device (1) is circulated by a closed drying system. The circulation route of the wet hot air in the cattle dung drying device (1) is: first entering a dust removal device (2) for dust removal, then entering a heat exchange device (3) to exchange heat with fresh air delivered from a fresh air delivery device (5), after completing temperature reduction and water removal, entering a heat pump device (4) to remove water and increase temperature, and then becoming dry hot air, and then entering the cattle dung drying device (1) again. The air temperature after completing temperature reduction is 40-80℃, and the relative humidity is 100%-80%. The air temperature after completing water removal and temperature increase is 70-100℃, and the relative humidity is 10%-1%. The closed drying system comprises the dust removal device (2), the heat exchange device (3) and the heat pump device (4). The heat exchange device (3) is further connected with a fresh air circulation system, and the fresh air circulation system comprises the fresh air delivery device (5), an air return adjusting device (6) and an air exhaust adjusting device (7). The air flow route in the fresh air circulation system is: fresh air is delivered into the heat exchange device (3) by the fresh air delivery device (5), and after completing heat exchange with the wet hot air after dust removal, part of the fresh air enters the cattle dung fermentation device (8), part of the fresh air is exhausted by the air exhaust adjusting device (7), and part of the fresh air returns to the fresh air delivery device (5) by the air return adjusting device (6). The cattle dung fermentation device (8) ferments the cattle dung dried by the cattle dung drying device by using the fresh air treated by the fresh air circulation system.

2. The method of using the closed drying and fresh air fermentation combined type cow dung treatment system according to claim 1, characterized in that, The method comprises the following steps: (1) pretreating the cattle dung, and the water content of the pretreated cattle dung is 55%-65%; (2) putting the cattle dung into the cattle dung drying device (1) for drying, and then putting the cattle dung with a water content lower than 48% into the cattle dung fermentation device (8); (3) performing fresh air fermentation treatment on the cattle dung for 5-7 days, and then obtaining qualified treated cattle dung.

3. The method of using the closed drying and fresh air fermentation combined type cow dung treatment system according to claim 2, characterized in that, The pretreatment of the cattle dung in step (1) comprises impurity removal and water removal of the cattle dung.

4. The method of using the closed type drying and fresh air fermentation combined type cow dung treatment system as claimed in claim 2, wherein, The specific steps of the pretreatment of the cattle dung are: removing impurities and other waste materials from the cattle dung with an initial solid content of 5%-10%, filtering the cattle dung mixture, retaining the solid materials in the cattle dung, and finally extruding and dehydrating the solid materials.

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