An oil extraction system for kitchen waste and food waste

Abstract

The present invention relates to the technical field of kitchen waste and food waste treatment, and provides a non-thermal oil extraction system for kitchen waste and food waste. According to the characteristics that vegetable oil in grease does not solidify, fat solidifies at low temperature, and there is a density difference between grease and water, the hydrolysis and acidification system liquefies the solid organic matter in the centrifuged residue through extracellular enzymes produced by hydrolysis microorganisms, destabilizes and stratifies the fat lacking organic matter nuclei, and then discharges the acidified liquid after hydrolysis and acidification into the secondary centrifugation to achieve the purpose of oil extraction. Microorganisms are used to stratify the grease, instead of the traditional method of heating to stratify the grease. This is the core of this patented invention. It reduces energy consumption and odor concentration, and achieves the purpose of energy conservation and consumption reduction while ensuring the oil extraction rate. Without heating throughout the process while ensuring the oil extraction rate, the composition and properties of the grease are not changed, which is beneficial to the further resource utilization of the grease.

Description

Technical Field

[0001] The present invention relates to the technical field of kitchen waste and food waste treatment, and particularly relates to a heat-free oil extraction system for kitchen waste and food waste. Background Art

[0002] Kitchen waste and food waste contain a certain amount of oil, which can be used as a chemical raw material and has high economic value. This oil consists of vegetable oil and fat. There is a density difference between vegetable oil and water, and they can be naturally separated at room temperature by a three-phase centrifuge; while fat is solid at room temperature, cannot be naturally separated, and cannot be separated by a three-phase centrifuge.

[0003] In the existing process of kitchen waste and food waste treatment, the waste is first drained of water, and then the unusable impurities are sorted out. The remaining organic matter after sorting is made into a slurry, which contains animal fat. To extract the fat and improve the oil extraction rate, the slurry needs to be heated to make the fat layer; there is a density difference between the fat, vegetable oil and the slurry, and finally the hot slurry is pumped into a centrifuge to separate the vegetable oil and fat.

[0004] The existing heat extraction process for kitchen waste and food waste has the following defects:

[0005] First, some of the oil is contained in the sorted impurities, and the oil loss rate is relatively high;

[0006] Second, heating is required during the oil extraction process, consuming a large amount of heat energy;

[0007] Third, during the heating process, local overheating will occur, resulting in emulsification of some oil, mutual fusion with water, inability to generate a density difference, and ultimately inability to be separated by a centrifuge, causing some oil loss and increasing the subsequent sewage treatment cost and poor water treatment effect;

[0008] Fourth, during the heat extraction process, to save energy consumption and reduce the amount of heated slurry, the waste is drained of water and then made into a slurry for heating, but this will result in a high solid content in the slurry; the high-solid-content slurry and high temperature cause problems such as high wear rate of the centrifuge rotor, large equipment maintenance and repair workload;

[0009] Fifth, during the heat extraction process, the high temperature can diffuse the volatile odor in the liquid-phase slurry into the air, increasing the concentration and temperature of the odor, and aggravating the cost and difficulty of odor treatment. Summary of the Invention

[0010] The present invention aims to solve the above technical problems and innovates a heat-free oil extraction system for kitchen waste and food waste.

[0011] The technical solution of the present invention is a heatless oil extraction system for kitchen waste and food waste, which successively includes a receiving tank, a waste pretreatment and sorting system, a slurry pool, a sand removal tower, a primary centrifugation, a hydrolysis and acidification system, and a secondary centrifugation;

[0012] The receiving tank is used for discharging kitchen waste or food waste containing grease, and uses centrifugal slurry to wash the grease adhered to the impurities in the raw materials into the liquid phase, reducing the grease loss rate of the grease adhered to the impurities;

[0013] The waste pretreatment system is used for sorting impurities and making the organic matter into slurry and then discharging it into the slurry pool, reducing the wear, entanglement and blockage of the impurities on the pulping and oil extraction equipment, and improving the stability of the system;

[0014] The slurry pool stores the slurry to adjust the stability of the system, is connected to the receiving tank through a reflux channel driven by a pump, and washes the discharged kitchen waste or food waste through the reflux slurry;

[0015] The sand removal tower is used for removing heavy, hard and fine sand, reducing the wear of the impurities on the centrifuge equipment, and improving the stability of the system;

[0016] The primary centrifuge separates the non-condensable vegetable oil by using the density difference between the oil and the slurry, prevents the inhibition of the oil in the slurry with high oil content on the hydrolysis and acidification system, and pumps the centrifuged residue containing fat and the separated slurry into the hydrolysis and acidification system;

[0017] The hydrolysis and acidification system is used to liquefy the solid organic matter in the centrifuged residue through the extracellular enzymes produced by hydrolysis microorganisms, make the fat lacking organic matter nuclei destabilize and stratify, and then discharge the acidified liquid after hydrolysis and acidification into the secondary centrifugation to achieve the purpose of oil extraction. This is the core of this patented invention. The hydrolysis and acidification system also has the functions of discharging sand and discharging refractory floating slag;

[0018] In the traditional oil extraction of kitchen waste and food waste, heating is used to make the oil stratify and then centrifuge for separation. The innovation of the present invention is that without heating energy consumption and ensuring the oil extraction rate, microorganisms are used to liquefy the oil nuclei to make the oil destabilize and stratify, and multiple measures are taken to prevent oil loss and improve the operation stability of the oil extraction system; using centrifugal slurry to wash the grease adhered to the impurities in the raw materials into the liquid phase, reducing the grease loss rate of the grease adhered to the impurities.

[0019] As an implementation method, the waste pretreatment system is equipped with a first conveying device, and the first conveying device is used to convey the impurities separated by the waste pretreatment and sorting system and then dehydrate them by screw pressing and load them onto a vehicle for external transportation, reducing the grease loss adhered to the impurities.

[0020] As an implementation manner, the sand removal tower is equipped with a second loading device, which is used to collect the fine sand screened out by the sand removal tower for external transportation by truck. It can reduce the moisture content and reduce the loss of organic matter and grease carried away by the sand.

[0021] As an implementation manner, the secondary centrifugation is used to separate the layered solid fat by density difference, and the centrifuged residue is discharged back to the hydrolysis acidification system again for cyclic hydrolysis acidification. The primary three-phase centrifuge and the secondary three-phase centrifuge are jointly equipped with a third loading device, which is used to collect the grease separated by the primary three-phase centrifuge and the secondary three-phase centrifuge for external transportation by truck.

[0022] As an implementation manner, the primary three-phase centrifuge is equipped with a first flow metering unit and a second flow metering unit. The first flow metering unit is used to measure the flow rate of the slurry entering the primary three-phase centrifuge each time, and the second flow metering unit is used to measure the flow rate of the grease separated by the primary three-phase centrifuge each time. The primary three-phase centrifuge generates an oil yield rate according to the flow rate data measured by the first flow metering unit and the flow rate data measured by the second flow metering unit. And when the oil yield rate is greater than the first set value, the primary three-phase centrifuge sends a first control signal, and when the oil yield rate is less than the second set value, it sends a second control signal; the pump is equipped with a power adjustment unit, and the power adjustment unit is communicatively connected to the primary three-phase centrifuge. When receiving the first control signal, the power adjustment unit reduces the operating power of the pump to reduce the slurry return flow rate, and when receiving the second control signal, the power adjustment unit increases the operating power of the pump to increase the slurry return flow rate.

[0023] Detect the oil content rate of the impurities transported out. When the oil content rate of the impurities transported out is higher than the set value, increase the return flow rate of the primary centrifuged slurry until the oil content rate of the impurities is lower than the set value; detect the oil content rate of the secondary centrifuged acidified liquid. When the oil content rate of the acidified liquid is higher than the set value, reduce the feed flow rate of the acidified liquid until the oil content rate of the centrifuged acidified liquid is lower than the set value. The pump is equipped with a power adjustment unit. When receiving the first control signal, the power adjustment unit increases the operating power of the pump to increase the slurry return flow rate, and when receiving the second control signal, the power adjustment unit reduces the operating power of the pump to reduce the feed flow rate of the acidified liquid.

[0024] As an implementation manner, when receiving the first control signal, the power adjustment unit gradually reduces the operating power of the pump, and when receiving the second control signal, the power adjustment unit gradually increases the operating power of the pump.

[0025] As an implementation manner, both the first flow metering unit and the second flow metering unit are arranged outside the primary three-phase centrifuge.

[0026] As an implementation manner, the first flow metering unit is arranged at the inlet where the primary three-phase centrifuge discharges the slurry.

[0027] As an implementation manner, the second flow metering unit is arranged at the outlet where the primary three-phase centrifuge separates the vegetable oil.

[0028] The beneficial effects of the present invention compared with the prior art are as follows:

[0029] First, no water drainage is carried out, and all the oil in the water can be recovered; all the garbage entering the factory has to be rinsed and soaked with the recycled slurry, reducing the oil content carried by the separated impurities, thereby reducing the oil loss.

[0030] Second, through the microbial method, the oil in the slurry is stratified and directly separated by the centrifuge. During the oil extraction process, no heating is carried out, no heat energy is consumed, and the biological method of oil stratification improves the oil quality.

[0031] Third, no heating is carried out during oil extraction, which will not cause local overheating and oil emulsification, reducing the oil loss rate. Moreover, the oil extraction rate of the non-heating oil extraction method can also reach that of the heating oil extraction method, and it also reduces the odor concentration and the difficulty of odor treatment.

[0032] Fourth, because no heating is required, no water drainage is carried out during the whole treatment process. The prepared slurry has a high water content and a low solid content. At the same time, without heating, the material temperature is at room temperature, resulting in less wear of the centrifuge and less maintenance and repair work. Description of the Drawings

[0033] Figure 1 It is a functional block diagram of the oil extraction system for kitchen waste and food waste provided by the implementation manner of the present invention;

[0034] Figure 2 It is a functional block diagram of the primary three-phase centrifuge and the pump provided by the implementation manner of the present invention. Detailed Embodiments

[0035] The following combines the drawings to clearly and completely describe the above and other implementation manners and advantages of the present invention. Obviously, the described implementation manners are only part of the implementation manners of the present invention, rather than all the implementation manners.

[0036] In one implementation manner, as Figure 1 shown.

[0037] The oil extraction system for kitchen waste and food waste provided by this embodiment includes a feeding tank, a waste pretreatment system, a slurry tank, a sand removal tower, a primary three-phase centrifuge, a hydrolysis acidification system, and a secondary three-phase centrifuge connected in sequence. The feeding tank is used for discharging kitchen waste and food waste. The waste pretreatment system is used for sorting impurities, organic matter, and water, and making the organic matter and water into slurry and discharging it into the slurry tank. The slurry tank is connected to the feeding tank through a reflux channel driven by a pump. The sand removal tower is used for removing heavy, hard, and fine sand. The primary three-phase centrifuge is used for separating vegetable oil, mixing the centrifugal residue with the separated slurry, and discharging it into the hydrolysis acidification system. The hydrolysis acidification system is used for liquefying the solid organic matter in the centrifugal residue through extracellular enzymes produced by hydrolysis microorganisms, destabilizing and stratifying the fat lacking organic matter nuclei, and then discharging the acidified liquid after hydrolysis acidification into the secondary three-phase centrifuge. The secondary three-phase centrifuge is used for separating the stratified fat, discharging the centrifugal residue back into the hydrolysis acidification system again, and performing cyclic hydrolysis acidification.

[0038] In this embodiment, the oil extraction system for kitchen waste and food waste consists of a feeding tank, a waste pretreatment system, a slurry tank, a sand removal tower, a primary three-phase centrifuge, a hydrolysis acidification system, and a secondary three-phase centrifuge. The oil extraction process for kitchen waste and food waste is as follows: Kitchen waste and food waste are unloaded into the feeding tank, the slurry tank reflux pump is started, and the slurry refluxes to the feeding tank to soak and wash the waste. At the same time, the plastic bags in the waste are broken to release the waste in the plastic bags, reducing oil loss, and then it enters the waste pretreatment system. After the waste enters the pretreatment system, the unusable impurities are sorted out, and the organic matter and water are made into slurry. After the waste is made into slurry, it enters the slurry tank. Part of the slurry is refluxed to the feeding tank through a pump to continue washing the waste, and the other part of the slurry enters the sand removal tower to remove heavy, hard, and fine sand, reducing the wear of the three-phase centrifuge. The slurry after sand removal enters the primary three-phase centrifuge. Because the density of vegetable oil and water is inconsistent, it can be separated by the three-phase centrifuge. The animal fat in the raw material is solid and is separated into the centrifugal residue. The centrifugal residue is mixed with the separated slurry and enters the hydrolysis acidification system. The slurry after the first oil removal enters the hydrolysis acidification system. In the hydrolysis acidification system, the solid organic matter is liquefied through extracellular enzymes produced by hydrolysis microorganisms, and the fat lacking organic matter nuclei is destabilized and stratified. The acidified liquid after hydrolysis acidification enters the secondary three-phase centrifuge. The density of the oil without nuclei is different from that of water, and it can be separated by the three-phase centrifuge. The animal fat that has not been completely hydrolyzed in the acidified liquid is still separated into the centrifugal residue, and the centrifugal residue is returned to the hydrolysis acidification system again for cyclic hydrolysis acidification. Finally, all the oil in the slurry is extracted. During the whole oil extraction process, the slurry is not heated, and the vegetable oil is directly separated by the three-phase centrifuge. The animal fat is broken by the hydrolysis acidification system, hydrolyzed into liquid oil, and then separated by the three-phase centrifuge. Finally, the process of oil extraction from kitchen waste / food waste without heating is realized.

[0039] In this embodiment, the oil extraction system for kitchen waste and restaurant kitchen waste does not require heating during the oil extraction process, which subverts the traditional characteristic that heating is required for oil extraction and has the following beneficial effects: First, no drainage is required, and all the oil in the water can be recovered; all garbage entering the factory must be rinsed and soaked in the reflux slurry, which reduces the content of oil carried by the separated impurities, thereby reducing oil loss. Second, through microbial methods, the oil in the slurry is separated into layers and directly separated by a centrifuge. The oil extraction process does not require heating and does not consume heat energy. Third, the oil extraction does not require heating, which will not cause local overheating and oil emulsification, thereby reducing the oil loss rate. Fourth, because heating is not required, the entire treatment process does not require drainage, and the resulting slurry has a high water content and a low solid content. At the same time, without heating, the material temperature is kept at room temperature, resulting in less wear on the centrifuge and less maintenance and repair.

[0040] In one embodiment, Figure 1 shown.

[0041] The oil extraction system for kitchen waste and restaurant kitchen waste provided in this embodiment has a waste pretreatment system equipped with a first loading device for collecting impurities separated by the waste pretreatment system for loading onto trucks for transport. Furthermore, the grit removal tower is equipped with a second loading device for collecting fine sand sieved by the grit removal tower for loading onto trucks for transport. Furthermore, the primary and secondary three-phase centrifuges are both equipped with a third loading device for collecting oil separated by the primary and secondary three-phase centrifuges for loading onto trucks for transport.

[0042] In this embodiment, the first, second, and third loading devices are all loading tools. The first loading device is configured in the waste pretreatment system to receive impurities separated by the waste pretreatment system. As previously mentioned, these impurities are unusable and are separated from organic matter and water. The second loading device is configured in the desanding tower to receive fine sand screened out of the desanding tower. Removing the fine sand reduces wear on the primary and secondary three-phase centrifuges. The third loading device is configured in both the primary and secondary three-phase centrifuges, serving as a shared device for receiving vegetable oils and hydrolyzed liquid animal fats.

[0043] In one embodiment, Figure 2 shown.

[0044] The oil extraction system for kitchen waste and food waste provided by this embodiment is equipped with a first flow metering unit and a second flow metering unit on the primary three-phase centrifuge. The first flow metering unit is used to measure the flow rate of the slurry entering the primary three-phase centrifuge for the current time, and the second flow metering unit is used to measure the flow rate of the oil separated by the primary three-phase centrifuge for the current time. The primary three-phase centrifuge generates an oil production rate based on the flow rate data measured by the first flow metering unit and the flow rate data measured by the second flow metering unit. Moreover, the primary three-phase centrifuge sends a first control signal when the oil production rate is greater than the first set value, and sends a second control signal when the oil production rate is less than the second set value. The pump is equipped with a power adjustment unit, and the power adjustment unit is communicatively connected to the primary three-phase centrifuge. The power adjustment unit reduces the operating power of the pump to reduce the slurry return flow rate when receiving the first control signal, and increases the operating power of the pump to increase the slurry return flow rate when receiving the second control signal.

[0045] In this embodiment, the oil extraction system for kitchen waste and food waste is different from the traditional oil extraction system in that the kitchen waste and food waste are unloaded into the receiving tank, and the slurry pool reflux pump is turned on. The slurry flows back to the receiving tank to soak and wash the waste. Through sufficient soaking and washing, the loss of oil from the released waste can be reduced. That is, by enabling a large amount of slurry to flow back, the oil yield rate can be increased. On this basis, for the oil extraction system for kitchen waste and food waste provided in this embodiment, further, by setting the first set value and the second set value as the upper limit value and the lower limit value as the comparison data of the oil yield rate, that is, when the oil yield rate of the primary three-phase centrifuge is greater than the first set value, the power adjustment unit reduces the operating power of the pump to reduce the slurry return flow rate. When the oil yield rate of the primary three-phase centrifuge is less than the second set value, the power adjustment unit increases the operating power of the pump to increase the slurry return flow rate. As mentioned above, to increase the oil yield rate, slurry reflux is required. After sufficient soaking and washing, the loss of oil from the released waste can be reduced, which means that after the slurry flows back and is discharged from the waste pretreatment system, more oil can be carried out. Thus, a higher oil yield rate is obtained after being discharged into the primary three-phase centrifuge. And the oil yield rate is positively correlated with the slurry return flow rate. The problem faced in practice is that increasing the oil yield rate involves slurry reflux for soaking and washing, which will result in a reduction in the slurry discharged into the primary three-phase centrifuge, thus affecting the oil extraction efficiency. Therefore, in this embodiment, by setting the first set value and the second set value, when the oil yield rate of the primary three-phase centrifuge is greater than the first set value, the power adjustment unit reduces the operating power of the pump to reduce the slurry return flow rate. When the oil yield rate of the primary three-phase centrifuge is less than the second set value, the power adjustment unit increases the operating power of the pump to increase the slurry return flow rate, thereby balancing the oil yield rate and the oil extraction efficiency. Preferably, when the power adjustment unit receives the first control signal, it gradually reduces the operating power of the pump. When the power adjustment unit receives the second control signal, it gradually increases the operating power of the pump. In this embodiment, when performing the adjustment task, whether reducing the slurry return flow rate or increasing the slurry return flow rate, it is a gradual adjustment process, that is, gradually reducing the slurry return flow rate or gradually increasing the slurry return flow rate. This means that for any operation of the primary three-phase centrifuge, the oil yield rate is different and gradually increases or gradually decreases. It also means that the slurry flowing back to the receiving tank is not a fixed value, and the slurry used for soaking and washing in the receiving tank also changes dynamically. At each increment, the oil of the waste can be released more fully. Therefore, the oil yield rate and the oil extraction efficiency are dynamically balanced. Also based on such a dynamic balance, a higher overall oil yield rate is achieved.

[0046] In one embodiment, for the oil extraction system of food waste and kitchen waste, both the first flow metering unit and the second flow metering unit are arranged outside the primary three-phase centrifuge. The first flow metering unit is arranged at the inlet where the primary three-phase centrifuge discharges the slurry. The second flow metering unit is arranged at the outlet where the primary three-phase centrifuge separates vegetable oil.

[0047] In this embodiment, an architecture is adopted in which the primary three-phase centrifuge, the first flow metering unit, and the second flow metering unit are separately arranged. Among them, the first flow metering unit is arranged at the inlet where the primary three-phase centrifuge discharges the slurry. The second flow metering unit is arranged at the outlet where the primary three-phase centrifuge separates vegetable oil.

[0048] The above-described specific embodiments further elaborate on the invention purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. It is particularly pointed out that for those skilled in the art, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An oil extraction system for kitchen waste and food waste, which successively includes a feeding tank, a garbage pretreatment and sorting system, a slurry pool, a sand removal tower, a primary centrifuge, a hydrolysis and acidification system, and a secondary centrifuge; The feeding tank is used for discharging kitchen waste or food waste containing grease; The garbage pretreatment system is used for sorting impurities and making organic matter into slurry and then discharging it into the slurry pool; The slurry pool is connected to the feeding tank through a reflux channel driven by a pump, and the kitchen waste or food waste discharged is washed by the reflux slurry; The sand removal tower is used for removing heavy, hard and fine sand; The primary centrifuge separates the non-condensable vegetable oil by using the density difference between oil and slurry, and pumps the centrifugal slag containing fat and the separated slurry into the hydrolysis and acidification system; The hydrolysis and acidification system is used for liquefying the solid organic matter in the centrifugal slag through the extracellular enzymes produced by hydrolysis microorganisms, destabilizing and stratifying the fat lacking organic matter nuclei, and then discharging the acidified liquid after hydrolysis and acidification into the secondary centrifuge; The secondary centrifuge is used for separating the stratified solid fat by using the density difference, and discharging the centrifugal slag back into the hydrolysis and acidification system again for cyclic hydrolysis and acidification; The primary centrifuge and the secondary centrifuge are jointly equipped with a third conveying device, which is used for collecting, temporarily storing and then loading and transporting the oil separated by the primary centrifuge and the secondary centrifuge; The primary centrifuge is equipped with a first flow metering unit and a second flow metering unit. The first flow metering unit is used for measuring the flow rate of the slurry entering the primary centrifuge each time, and the second flow metering unit is used for measuring the flow rate of the oil separated by the primary centrifuge each time. The primary centrifuge generates an oil extraction rate according to the flow rate data measured by the first flow metering unit and the flow rate data measured by the second flow metering unit; and when the oil output rate of the primary three-phase centrifuge is greater than the first set value, it sends a first control signal, and when the oil output rate is less than the second set value, it sends a second control signal; The pump is equipped with a power adjustment unit, and the power adjustment unit is communicatively connected with the primary three-phase centrifuge. When receiving the first control signal, the power adjustment unit reduces the operating power of the pump to reduce the slurry reflux flow rate, and when receiving the second control signal, the power adjustment unit increases the operating power of the pump to increase the slurry reflux flow rate.

2. The oil extraction system for kitchen waste and food waste according to claim 1, wherein The garbage pretreatment system is equipped with a first conveying device, which is used for conveying the impurities separated by the garbage pretreatment and sorting system and then dehydrating them by screw pressing and loading and transporting them out; 3. The oil extraction system for kitchen waste and food waste according to claim 1, characterized in that, The sand removal tower is equipped with a second conveying device, which is used for dehydrating the fine sand discharged from the sand removal tower by screw pressing and loading and transporting them out; 4. The oil extraction system for kitchen waste and food waste according to claim 1, wherein When receiving the first control signal, the power adjustment unit gradually increases the operating power of the pump, and when receiving the second control signal, the power adjustment unit gradually reduces the operating power of the pump.

5. The oil extraction system for kitchen waste and food waste according to claim 1, characterized in that Both the first flow metering unit and the second flow metering unit are arranged outside the primary centrifuge.

6. The oil extraction system for kitchen waste and food waste according to claim 5, characterized in that, The first flow metering unit is arranged at the inlet where the slurry pool pumps into the feeding tank.

7. The oil extraction system for kitchen waste and food waste according to claim 1, characterized in that, The second flow metering unit is arranged at the feed pipe opening of the secondary centrifuge.

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