A multi-stage recovery system and method for usable oil in kitchen waste

Abstract

The present invention relates to the field of kitchen waste treatment, and in particular to a multi-stage recovery system and method for usable oil in kitchen waste. After kitchen waste in a storage tank is crushed, multi-stage hydrothermal reactors are sequentially arranged, so that the multiple reactors can achieve graded treatment of the kitchen waste, and the oil phase in the kitchen waste is completely separated step by step, so that the usable oil in the kitchen waste can be extracted through each stage in turn, and the usable oil extracted at each stage is recycled, thereby greatly improving the recovery rate of the usable oil in the kitchen waste, separating different oil phases step by step through hydrothermal reaction, helping the kitchen waste to completely remove grease, and improving the economic benefits of kitchen waste treatment.

Description

Technical Field

[0001] The invention relates to the field of restaurant kitchen waste treatment, and in particular to a multi-stage recovery system and method for usable oil in restaurant kitchen waste. Background Art

[0002] With the rapid development of my country's social economy and the improvement of people's living standards, the amount of food waste is increasing day by day, and it has become an important source of pollution affecting the living environment. Food waste has a complex composition, which is a mixture of oil, bones, waste tableware, plastic and other substances. It has the characteristics of high oil content, more organic matter and impurities. If it can be effectively and reasonably utilized and treated, it can be turned into treasure and alleviate the pollution pressure caused by it to the environment.

[0003] Generally speaking, bio-oil in restaurant waste can account for 1-3% of the total weight of the waste, and may even be as high as about 10%. The bio-oil contained in restaurant waste is a high-quality raw material for the production of chemical products such as biodiesel, stearic acid and oleic acid. The amount of bio-oil from restaurant waste in urban areas of my country can produce more than 3.98 million tons of biodiesel each year. If it is fully utilized, it can solve the production capacity problem of biodiesel enterprises and eliminate the harm caused by its return to the dining table. It has a high recycling value.

[0004] Since the treatment of food waste in my country started late, there are disadvantages such as simple process, small processing capacity, high equipment failure rate, etc., and the separation of oil in the solid phase of food waste is difficult and the content is high. At present, the theoretical amount of waste oil generated by food waste in my country is more than 11 million tons, but in fact, the waste oil entering the biodiesel industry chain is less than 2 million tons per year. At the same time, the existing oil extraction and treatment method, filtrate heating-centrifugation technology, heats the filtrate through a heater, and then quantitatively and evenly flows into a horizontal centrifuge for solid-liquid separation; the separated high-oil liquid is heated again, and then enters a vertical centrifuge for oil-water separation, and finally obtains oil with higher purity. However, this method has a low oil extraction rate and can only separate the floating oil in food waste. Other dissolved oils in food waste cannot be separated. Moreover, due to the high-speed rotation of the centrifuge, the high flow rate will also cause serious secondary emulsification of oily wastewater. Summary of the invention

[0005] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide a multi-stage recovery system and method for usable oil in food waste, so as to solve the technical problem of low recovery rate of usable oil in food waste in the prior art.

[0006] The present invention is achieved through the following technical solutions:

[0007] A multi-stage recovery system for usable oil in kitchen waste comprises a storage tank, a crushing and sorting device, a primary hydrothermal reactor, a secondary hydrothermal reactor, a tertiary hydrothermal reactor and a tail water treatment device; the output end of the storage tank is connected to the input end of the crushing and sorting device, the output end of the crushing and sorting device is connected to the input end of the primary hydrothermal reactor, the output end of the primary hydrothermal reactor is connected to the input end of the secondary hydrothermal reactor, the output end of the secondary hydrothermal reactor is connected to the input end of the tertiary hydrothermal reactor, and the output end of the tertiary hydrothermal reactor is connected to the tail water treatment device.

[0008] Preferably, a first delivery pump is provided between the output end of the crushing and sorting device and the input end of the primary hydrothermal reactor.

[0009] Preferably, an oil separator and a second delivery pump are sequentially arranged between the output end of the first hydrothermal reactor and the input end of the second hydrothermal reactor.

[0010] Preferably, a gas dissolving device and a third delivery pump are provided in sequence between the output end of the secondary hydrothermal reactor and the input end of the tertiary hydrothermal reactor.

[0011] Preferably, a separation device and a fourth delivery pump are provided in sequence between the tertiary hydrothermal reactor and the tail water treatment device.

[0012] A multi-stage recovery method for usable oil in food waste, based on the multi-stage recovery system for usable oil in food waste described above, comprises the following steps:

[0013] Step 1: The food waste enters the storage tank from the storage tank inlet, and enters the crushing and sorting device through the storage tank to crush and separate the water-insoluble solid phase products in the food waste;

[0014] Step 2, the crushed and sorted food waste enters a primary hydrothermal reactor, where it remains stationary and the floating oil is separated for recycling;

[0015] Step 3, the kitchen waste is subjected to low-temperature hydrolysis in a secondary hydrothermal reactor 7 to separate the oil and fat for recycling;

[0016] Step 4: The kitchen waste is hydrolyzed at high temperature in a three-stage hydrothermal reactor to separate the bio-oil for recycling.

[0017] Preferably, in step 2, the kitchen waste is allowed to stand at a temperature below 80° C. in a primary hydrothermal reactor and then discharged through an oil separator using an oil collecting pipe, skimmed by a skimmer or manually skimmed to separate the floating oil for recycling.

[0018] Preferably, in step 3, the kitchen waste is subjected to low-temperature hot water hydrolysis at 80°C-200°C and 0.5-2MPa in a secondary hydrothermal reactor for 30-60 minutes, and then enters a dissolving gas device, where air is added to increase pressure, a DC electrode is installed for electrolysis, or impeller flotation or jet flotation is used to generate bubbles to adhere to oil with a density similar to that of the bubbles, and the bubbles gradually move upward, and the grease is finally separated for recycling.

[0019] Preferably, in step 4, the food waste is subjected to high temperature hydrolysis at 260°C-320°C and 7-20MPa in a three-stage hydrothermal reactor for 30-80 minutes, and then filtered in a separation device and then extracted with a strong polar solvent to separate the bio-oil for recycling.

[0020] Preferably, the highly polar solvent is toluene or ether.

[0021] Compared with the prior art, the present invention has the following beneficial technical effects:

[0022] The present invention provides a multi-stage recovery system for usable oil in food waste. After food waste in a storage tank is crushed, multi-stage hydrothermal reactors are sequentially arranged, so that the multiple reactors can realize graded treatment of food waste, and the oil phase in the food waste is completely separated step by step, so that the usable oil in the food waste can be extracted through each stage in turn, and the usable oil extracted in each stage is recycled, which greatly improves the recovery rate of the usable oil in the food waste. Different oil phases are separated step by step through hydrothermal reaction, which helps to completely remove grease from the food waste and improves the economic benefits of food waste treatment.

[0023] Furthermore, a first delivery pump is arranged between the output end of the crushing and sorting device and the input end of the primary hydrothermal reactor, so that the food waste passing through the crushing and sorting device can be delivered to the primary hydrothermal reactor through the first delivery pump to extract the primary usable oil from the food waste.

[0024] Furthermore, an oil separator and a second delivery pump are successively arranged between the output end of the first hydrothermal reactor and the input end of the second hydrothermal reactor, so that the food waste passing through the first hydrothermal reactor can be transported to the second hydrothermal reactor through the oil separator and the second delivery pump to extract secondary usable oil from the food waste.

[0025] Furthermore, an air dissolving device and a third delivery pump are provided in sequence between the output end of the secondary hydrothermal reactor and the input end of the tertiary hydrothermal reactor, so that the food waste passing through the secondary hydrothermal reactor can be transported to the tertiary hydrothermal reactor through the air dissolving device and the third delivery pump to extract tertiary usable oil from the food waste.

[0026] The present invention also provides a multi-stage recovery method for usable oil in food waste, wherein usable oil is extracted from food waste through multi-stage hydrothermal reaction, and each hydrothermal reactor is set with different reaction temperatures, reaction pressures and reaction times to separate different oils in multiple stages for recovery and utilization, thereby greatly improving the recovery rate of usable oil in food waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the multi-stage bio-oil recovery system in the present invention.

[0028] In the figure: 1-storage tank; 2-crushing and sorting device; 3-first delivery pump; 4-primary hydrothermal reactor; 5-oil separator; 6-second delivery pump; 7-secondary hydrothermal reactor; 8-gas dissolving device; 9-third delivery pump; 10-third-stage hydrothermal reactor; 11-separation device; 12-fourth delivery pump; 13-tail water treatment device. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0032] The object of the present invention is to provide a multi-stage recovery system and method for usable oil in food waste, so as to solve the technical problem of low recovery rate of usable oil in food waste in the prior art.

[0033] Specifically, according to Figure 1As shown, the multi-stage recovery system of usable oil in kitchen waste comprises a storage tank 1, a crushing and sorting device 2, a primary hydrothermal reactor 4, a secondary hydrothermal reactor 7, a tertiary hydrothermal reactor 10 and a tail water treatment device 13; the output end of the storage tank 1 is connected to the input end of the crushing and sorting device 2, the output end of the crushing and sorting device 2 is connected to the input end of the primary hydrothermal reactor 4, the output end of the primary hydrothermal reactor 4 is connected to the input end of the secondary hydrothermal reactor 7, the output end of the secondary hydrothermal reactor 7 is connected to the input end of the tertiary hydrothermal reactor 10, and the output end of the tertiary hydrothermal reactor 10 is connected to the tail water treatment device 13.

[0034] Specifically, a first delivery pump 3 is provided between the output end of the crushing and sorting device 2 and the input end of the primary hydrothermal reactor 4 .

[0035] Specifically, an oil separator 5 and a second delivery pump 6 are sequentially arranged between the output end of the primary hydrothermal reactor 4 and the input end of the secondary hydrothermal reactor 7 .

[0036] Specifically, a gas dissolving device 8 and a third delivery pump 9 are sequentially provided between the output end of the secondary hydrothermal reactor 7 and the input end of the tertiary hydrothermal reactor 10 .

[0037] Specifically, a separation device 11 and a fourth delivery pump 12 are sequentially provided between the tertiary hydrothermal reactor 10 and the tail water treatment device 13 .

[0038] The present invention also provides a multi-stage recovery method for usable oil in food waste, based on the multi-stage recovery system for usable oil in food waste described above, comprising the following steps:

[0039] Step 1, the food waste enters the storage tank 1 from the inlet of the storage tank 1, and enters the crushing and sorting device 2 through the storage tank 1, and the water-insoluble solid phase products in the food waste are crushed and separated;

[0040] Step 2, the crushed and sorted food waste enters the primary hydrothermal reactor 4, where it remains stationary and the floating oil is separated for recycling;

[0041] Step 3, the kitchen waste is subjected to low-temperature hydrolysis in a secondary hydrothermal reactor 7 to separate the oil and fat for recycling;

[0042] Step 4: The kitchen waste is hydrolyzed at high temperature in a tertiary hydrothermal reactor 10 to separate the bio-oil for recycling.

[0043] Specifically, after the kitchen waste is allowed to stand at a temperature below 80° C. in the primary hydrothermal reactor 4, it is discharged through the oil separator 5 using an oil collecting pipe, skimmed by a skimmer or manually skimmed to separate the floating oil for recycling.

[0044] Specifically, after the food waste is subjected to low-temperature hot water hydrolysis at 80°C-200°C and 0.5-2MPa for 30-60 minutes in the secondary hydrothermal reactor 7, it enters the aeration device 8, where air is added to increase pressure, and DC electrodes are installed for electrolysis, or impeller flotation or jet flotation is used to generate bubbles to adhere to oil with a density similar to that of the bubbles, which gradually moves upward, and finally the grease is separated for recycling.

[0045] Specifically, the kitchen waste is subjected to high temperature hydrolysis at 260°C-320°C and 7-20MPa for 30-80 minutes in the three-stage hydrothermal reactor 10, and then filtered in a separation device and then extracted with a strong polar solvent to separate the bio-oil for recycling.

[0046] Specifically, in the present invention, the oil separator 5 obtains the floatable oil by skimming with special machinery such as an oil collecting pipe or by manual skimming, the gas dissolving device 8 separates the grease by flotation, and the separation device 11 separates the bio-oil by solvent extraction. The oil separator 5 includes but is not limited to a horizontal flow oil separator, etc.; the gas dissolving device 8 includes but is not limited to pressurization, electrolysis or adding jet flotation and other equipment; the solvent added to the separation device 11 includes but is not limited to toluene, ether, etc., and the tail water treatment device 10 includes but is not limited to a wastewater biological treatment device, an anaerobic nitrification device, an MBR device, etc.

[0047] In summary, the present invention provides a multi-stage recovery system for usable oil in food waste, which crushes the food waste in the storage tank and then sequentially arranges multi-stage hydrothermal reactors, so that the multiple reactors can realize graded treatment of the food waste, and the oil phase in the food waste is completely separated step by step, so that the usable oil in the food waste can be extracted through each stage in turn, and the usable oil extracted at each stage is recycled, which greatly improves the recovery rate of the usable oil in the food waste, separates different oil phases step by step through hydrothermal reaction, helps to completely remove grease from the food waste, and improves the economic benefits of food waste treatment.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A multi-stage recovery method for usable oil in food waste, based on a multi-stage recovery system for usable oil in food waste, characterized in that: The invention comprises a storage tank (1), a crushing and sorting device (2), a primary hydrothermal reactor (4), a secondary hydrothermal reactor (7), a tertiary hydrothermal reactor (10) and a tail water treatment device (13); the output end of the storage tank (1) is connected to the input end of the crushing and sorting device (2), the output end of the crushing and sorting device (2) is connected to the input end of the primary hydrothermal reactor (4), the output end of the primary hydrothermal reactor (4) is connected to the input end of the secondary hydrothermal reactor (7), the output end of the secondary hydrothermal reactor (7) is connected to the input end of the tertiary hydrothermal reactor (10), and the output end of the tertiary hydrothermal reactor (10) is connected to the tail water treatment device (13). A first delivery pump (3) is arranged between the output end of the crushing and sorting device (2) and the input end of the first hydrothermal reactor (4), an oil separator (5) and a second delivery pump (6) are arranged in sequence between the output end of the first hydrothermal reactor (4) and the input end of the second hydrothermal reactor (7), a gas dissolving device (8) and a third delivery pump (9) are arranged in sequence between the output end of the second hydrothermal reactor (7) and the input end of the third hydrothermal reactor (10), and a separation device (11) and a fourth delivery pump (12) are arranged in sequence between the third hydrothermal reactor (10) and the tail water treatment device (13); The steps include: Step 1, the food waste enters the storage tank (1) from the inlet of the storage tank (1), and enters the crushing and sorting device (2) through the storage tank (1), so as to crush and separate the water-insoluble solid phase products in the food waste; Step 2, the crushed and sorted food waste enters a primary hydrothermal reactor (4), is kept still, and the floating oil is separated for recycling. After the food waste is kept still at a temperature below 80° C. in the primary hydrothermal reactor (4), it is discharged through an oil separator (5) using an oil collecting pipe, skimmed by a skimmer, or manually skimmed, and the floating oil is separated for recycling; Step 3, the food waste is subjected to low-temperature hydrolysis in a secondary hydrothermal reactor (7) to separate the oil and fat for recycling. After the food waste is subjected to low-temperature hot hydrolysis at 80°C-200°C and 0.5-2MPa in the secondary hydrothermal reactor (7) for 30-60 minutes, it enters the gas dissolving device (8), is pressurized after adding air, and is electrolyzed by installing DC electrodes or using impeller flotation or jet flotation to generate bubbles to adhere to oil with a density similar to that of the bubbles, and gradually moves upward, and finally the oil and fat is separated for recycling; Step 4, the food waste is subjected to high-temperature thermal hydrolysis in a tertiary hydrothermal reactor (10) to separate the bio-oil for recycling. The food waste is subjected to high-temperature thermal hydrolysis at 260° C. to 320° C. and 7 to 20 MPa for 30 to 80 minutes in the tertiary hydrothermal reactor (10), and then filtered in a separation device and then extracted with a strong polar solvent to separate the bio-oil for recycling. The strong polar solvent is toluene or ether.

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