Production method of degreased peanuts

Abstract

The invention discloses a degreased peanut production method, which belongs to the field of food processing, and comprises the following steps: adding water into a reaction tank to submerge peanut kernels, filling CO2 to enable the solution to have acidity, heating the reaction tank, gradually increasing the pressure intensity, gradually reducing the pressure to complete a variable pressure procedure, continuously extracting liquid and gas in the reaction tank in the process, and introducing the liquid and gas into the reaction tank again, the transformation program is continuously repeated for more than two rounds; balancing to atmospheric pressure, discharging liquid, and vacuumizing, heating and dehydrating; and repeating the steps for more than two rounds in sequence to obtain the degreased peanuts. According to the method, CO2 is utilized to enable a solution for soaking peanuts to become acidic, grease in the peanuts is hydrolyzed through heating and pressurizing, the solution can permeate into the peanuts through circulating reflux, deep grease in the peanuts is hydrolyzed, the interiors of the single peanuts at different depths are hydrolyzed through a variable-pressure procedure, and lipid in the peanuts can be fully hydrolyzed. The method does not need to use an organic solvent, the production process is safer, and the obtained degreased peanuts do not have organic solvent residues.

Description

Technical Field

[0001] The invention relates to a method for producing defatted peanuts and belongs to the field of food processing. Background Art

[0002] As consumers' health awareness increases, the demand for low-fat, high-protein foods continues to grow. As a healthy ingredient, defatted peanuts have great potential for application in the food industry, especially in the fields of sports nutrition, functional foods and weight loss foods.

[0003] Defatted peanuts refer to peanuts that have been defatted. The main purpose is to reduce the fat content of peanuts while retaining their nutrients such as protein and cellulose. The traditional method uses mechanical pressing to remove the oil from peanuts, and the final result is defatted peanut powder, which is applicable to a narrow range of products when used in food production.

[0004] The defatted peanuts obtained by removing the oil from the peanuts while retaining the whole peanut kernel have a wide range of uses in food production. They can not only be further ground for baking, beverages, and sauces, but can also be kept intact for making snacks.

[0005] In the prior art, the oil in peanuts is usually extracted with organic solvents. After solid-liquid separation, the organic solvent in the peanuts is further evaporated to obtain complete defatted peanuts. This method may leave solvent residues in the peanuts, which may harm the health of consumers. In addition, organic solvents are volatile. If they are not properly handled during the production process, they will cause volatile organic compounds (VOCs) emissions and pollute the air. Organic solvents are also highly flammable. If the operation is improper or the equipment is poorly managed during the extraction process, there is a risk of causing fire or explosion accidents. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, under the premise of obtaining intact peanut particles, the present invention provides a method for producing defatted peanuts which is safer during production and the resulting product is also safer.

[0007] The technical solution adopted by the present invention to solve its technical problem is: A method for producing defatted peanuts comprises the following steps: Add water to the reaction tank until the peanut kernels placed in the reaction tank are submerged; Filling the reaction tank with carbon dioxide in an amount such that the solution in the reaction tank is always acidic in subsequent steps; The mixture in the reaction tank is heated, the pressure in the reaction tank is gradually increased and then gradually reduced to complete a round of pressure change procedure, during which the liquid and gas in the reaction tank are continuously extracted and re-introduced into the reaction tank to form a continuous circulation reflux, and the pressure change procedure is repeated for more than two rounds; Balancing to atmospheric pressure, discharging the liquid in the reaction tank, evacuating the reaction tank and heating the peanut kernels in the reaction tank to dehydrate the peanut kernels; Repeat the above steps in order for more than two rounds to obtain the defatted peanuts.

[0008] Carbon dioxide dissolves in water to form an acidic solution, which can hydrolyze the oil in peanuts. The circulation of reflux liquid and gas has a cavitation effect, which can make the solution penetrate into the interior of the peanuts for acidic hydrolysis. The pressure change operation allows the solution to penetrate deeper into the peanuts, strengthening the hydrolysis effect in the high-pressure stage. In the decompression stage, gas escape is used to form tiny bubbles that burst, thereby improving the permeability of the solution. No organic solvents are used in the entire process, thus avoiding the problem of organic solvent residues, ensuring product safety, and the operation process is environmentally friendly and pollution-free.

[0009] Furthermore, in the step of heating the mixture in the reaction tank, the heating temperature is above 80°C.

[0010] At temperatures above 80°C, the hydrolysis reaction rate increases significantly, helping to break down the oil in peanuts more quickly, shortening the process time and improving production efficiency.

[0011] Furthermore, the duration of each round of the voltage transformation procedure is 40 minutes to 60 minutes.

[0012] A longer pressure change program is set to make the pressurization and depressurization process change slowly, ensuring that the peanuts have enough time to hydrolyze in each pressure range, and that the circulating liquid and gas have enough time to cavitate on the peanuts in each pressure range, which is conducive to ensuring the uniformity and integrity of the degreasing effect.

[0013] Furthermore, in each round of the pressure change procedure, the time taken to gradually increase the pressure in the reaction tank is 30 minutes to 40 minutes, and the time taken to gradually reduce the pressure is 10 minutes to 20 minutes.

[0014] The pressurization time is beneficial to enhancing the penetration capacity of the acidic solution, and the decompression time is also longer, which is beneficial to the gradual dissolution of the hydrolysis products of the oil in the peanuts.

[0015] Furthermore, in each round of the pressure changing procedure, the end point of gradually increasing the pressure in the reaction tank is to increase the pressure to 10MPa~60MPa, and the end point of gradually reducing the pressure is to reduce the pressure to atmospheric pressure~4MPa.

[0016] The high pressure environment can effectively enhance the penetration of the solution, accelerate the hydrolysis of oil inside the peanuts, and the pressure ensures the integrity of the resulting defatted peanut particles.

[0017] High pressure can create a lower pH environment, making acidic hydrolysis more thorough, accelerating the breaking of fatty acyl bonds and further improving the efficiency of oil hydrolysis. At the same time, carbon dioxide creates acidic conditions and mild reaction conditions, which can reduce the loss of nutrients in peanuts.

[0018] Furthermore, in the pressure changing procedure, the pressurization method is: supplementing the circulating gas with carbon dioxide or a mixture of carbon dioxide and nitrogen; the pressure reduction method is: reducing the circulating gas.

[0019] By supplementing the pressure with carbon dioxide or a mixture of carbon dioxide and nitrogen, it is possible to maintain the acidic environment required for the reaction, flexibly adjust the pressure of the reaction system, and reduce the oxidation of some nutrients in the peanuts in a highly reactive environment; by reducing the circulating gas to reduce the pressure, the operation is simple and the decompression process can be effectively controlled to avoid damage to the peanut structure. At the same time, it facilitates the discharge of oil hydrolysis products from the inside of the peanuts, ensures the smooth progress of the pressure change program, and promotes the degreasing process of the peanuts.

[0020] Furthermore, the requirement for evacuating the reaction tank is that the pressure in the reaction tank is 6kPa~20kPa; the temperature for heating the peanut kernels in the reaction tank is 40℃~70℃, and the heating time is 10min~30min.

[0021] Evacuating the reaction tank to a pressure range of 6kPa~20kPa is beneficial to lowering the boiling point of water in the peanut kernels and accelerating dehydration. The peanut kernels are heated at a temperature of 40℃~70℃. At the same time, the heating time is between 10min~30min to ensure that the peanut kernels are fully dehydrated and retain most of the nutrients.

[0022] Furthermore, in the step of adding water to the reaction tank until the peanut kernels placed in the reaction tank are submerged, salt is dissolved in the added water.

[0023] Dissolving salt in water can form sodium fatty acids with the hydrolyzate, which can enhance the solubility of the hydrolyzate and further promote the hydrolysis and removal of oil. At the same time, it can also preliminarily pickle the peanuts for later storage or downstream food processing.

[0024] Furthermore, in the pressure change procedure, the liquid that is reintroduced into the reaction tank enters the reaction tank from the top of the reaction tank, and the gas that is reintroduced into the reaction tank enters the reaction tank from the bottom of the reaction tank.

[0025] Such a design can strengthen the impact of gas and liquid on peanuts, further promote the flow of solution around and inside the peanut kernels, increase the frequency of cavitation, allow the solution to penetrate more evenly into the peanuts, improve the uniformity and completeness of oil hydrolysis, and help improve the production quality of defatted peanuts.

[0026] The beneficial effects of the present invention are as follows: the defatted peanut production method of the present invention uses carbon dioxide to make the solution for soaking peanuts acidic, hydrolyzes the oil in the peanuts in a heated and pressurized environment, and the gas and liquid in the circulating reflux reaction tank can make the solution penetrate into the interior of the peanuts and hydrolyze the oil deep inside the peanuts. The solution has different penetration degrees into the peanuts under different pressures, and the pressure change procedure can cause acidic hydrolysis inside different depths of a single peanut, which is conducive to fully hydrolyzing the lipids in the peanuts, and finally obtaining complete defatted peanuts through solid-liquid separation and dehydration. The method does not require the use of organic solvents, the production process is safer, and the obtained defatted peanuts will not have organic solvent residues. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] It should be understood that, under the premise of no conflict, any and all embodiments of the present invention can be combined with the technical features in any other embodiment or multiple other embodiments to obtain another embodiment. The present invention includes such a combination to obtain another embodiment.

[0029] Unless otherwise specified, all technical and scientific terms used herein have the standard meaning in the field to which the claimed subject matter belongs. If there are multiple definitions for a term, the definition herein shall prevail.

[0030] The present application embodiment provides a method for producing defatted peanuts, comprising the following steps: S1: Add water to the reaction tank until the peanut kernels placed in the reaction tank are submerged.

[0031] S2: Fill the reaction tank with carbon dioxide in an amount that ensures that the solution in the reaction tank is always acidic in subsequent steps.

[0032] S3: heating the mixture in the reaction tank, gradually increasing the pressure in the reaction tank and then gradually reducing the pressure to complete a round of pressure change procedure. During the pressure change procedure, the liquid and gas in the reaction tank are continuously extracted and reintroduced into the reaction tank to form a continuous circulation reflux. The pressure change procedure is repeated for more than two rounds.

[0033] S4: Balance to atmospheric pressure, discharge the liquid in the reaction tank, evacuate the reaction tank and heat the peanut kernels in the reaction tank to dehydrate the peanut kernels.

[0034] Repeat the above steps in order for two or more rounds to obtain defatted peanuts.

[0035] That is, the actual execution steps may be, for example, S1-S2-S3-S3--S3-S4-S1-S2--S3-S3 -S4-S1-S2-S3-S3-S3-S4-S3-S3-S4 to obtain defatted peanuts.

[0036] Adding water to submerge the peanut kernels provides a reaction environment for the peanut kernels, allowing carbon dioxide to dissolve in water to form an acidic solution, creating conditions for subsequent oil hydrolysis, and reheating to promote the acidic hydrolysis reaction of the oil in the peanuts. Circulation and reflux can cause cavitation, forming cavitation bubbles in the solution. When the cavitation bubbles collapse, huge instantaneous pressure is generated. When the cavitation bubbles collapse near the surface of the peanuts, the huge instantaneous pressure can destroy the peanut epidermis and cell walls, so that the solution can pass through the surface of the peanuts into its interior and hydrolyze the oil contained in the peanuts. The variable pressure program allows the solution to cavitate under different pressures, thereby achieving a better cavitation effect. When the pressure increases, the solution is more likely to penetrate into the peanuts to hydrolyze the oil. When the pressure decreases, the solution is more likely to carry the hydrolysis products out of the peanuts, so that the efficiency of hydrolysis is improved. The degree of penetration of the solution into the peanuts is different under different pressures. The variable pressure program allows the solution to better penetrate into the peanuts under different pressures. Peanut tissues at different depths can fully contact the acidic solution, so that the oil is fully hydrolyzed in an acidic environment, which is beneficial to improving the oil hydrolysis efficiency and degreasing effect.

[0037] Repeating step S3 allows the solution to penetrate thoroughly into the peanuts for acid hydrolysis, thereby reducing the residual oil core inside the peanuts. Preferably, in each round of S1 to S4, S3 is repeated four to eight times. Repeating the pressure change procedure for multiple rounds further ensures that the oil at different positions inside the peanuts can be effectively hydrolyzed.

[0038] Vacuuming and heating to dehydrate after drainage can cause the peanuts to puff up and crack, especially the parts where the oil has been hydrolyzed, which are more likely to puff up and produce deeper cracks than the unhydrolyzed parts.

[0039] In the next round of S1 to S4, the solution of S3 continues to penetrate into the peanuts along the cracks, which is conducive to more thorough hydrolysis of the residual oil in the peanuts. Finally, complete defatted peanuts can be obtained, and the use of organic solvents is avoided, which improves the safety of the production process and prevents the harm of organic solvent residues to consumer health and the pollution of volatile organic compound emissions to the environment. Preferably, S1 to S4 are repeated four to eight times.

[0040] Preferably, in step S4, the pressure in the reaction tank is 6kPa~20kPa (absolute pressure); the temperature for heating the peanut kernels in the reaction tank is 40℃~70℃, and the heating time is 10min~30min, which is conducive to rapid dehydration. Specifically, before the S1-S4 cycle is completed, the heating time of step S4 is shorter, and the heating time of the last step S4 is longer, so that the peanuts are more conducive to storage.

[0041] In step S3, the liquid re-introduced into the reaction tank enters the reaction tank from the top of the reaction tank, and the gas re-introduced into the reaction tank enters the reaction tank from the bottom of the reaction tank. The gas enters from the bottom of the tank and passes through the surface of the peanuts, which can enhance the cavitation effect on the surface of the peanuts. After the liquid flows in from the top, it impacts the peanuts below by gravity, which can form a strong flow and local pressure change below, further strengthening the cavitation effect, ensuring that the fat inside and on the surface of the peanuts can be fully hydrolyzed.

[0042] In step S3, the heating temperature is above 80° C. Setting the heating temperature above 80° C. can accelerate the chemical reaction rate. Under acidic conditions, high temperature helps to accelerate the hydrolysis reaction of oil, so that the oil in peanuts is decomposed into glycerol and fatty acids more quickly, thereby improving production efficiency and shortening the production cycle of defatted peanuts.

[0043] Glycerol is soluble in water and can be easily removed with the solution when the liquid in the reaction tank is discharged in step S4. Some fatty acids have poor solubility, and multiple rounds of S1 to S4 are required to completely remove them. In order to improve production efficiency, the water added in step S1 can be adjusted to brine, such as salt water with a mass fraction of more than 0.1%. After being dissolved in water, table salt can effectively increase the ionic strength of the aqueous solution, generate sodium fatty acids with fatty acids, enhance the solubility of higher fatty acids, and facilitate the separation and removal of higher fatty acids during and after the hydrolysis process. At the same time, table salt can also penetrate into the peanuts during the hydrolysis process, preliminarily pickle the peanuts, and give the defatted peanuts a certain flavor basis, which is convenient for downstream snack processing or directly made into flavored peanut products.

[0044] In step S3, the duration of each round of voltage transformation is 40 minutes to 60 minutes, ensuring that the oil inside and outside the peanuts can fully contact the acid solution and complete a relatively thorough hydrolysis within one voltage transformation cycle. At the same time, it avoids the reduction of efficiency or unnecessary load on the equipment due to too long a time, ensuring the efficiency and stability of the entire process.

[0045] For example, the time for gradually increasing the pressure in the reaction tank is 30 minutes to 40 minutes, and the time for gradually reducing the pressure is 10 minutes to 20 minutes. A longer pressurization time can slowly increase the pressure, so that the solution can gradually penetrate into the peanuts. The decompression time is conducive to the rapid release of the hydrolyzate and its full mixing with the solution.

[0046] Specifically, in each round of pressure change procedure, the end point of gradually increasing the pressure in the reaction tank is to increase the pressure to 10MPa~60MPa. When the pressure is increased to 10MPa~60MPa, the permeability of the solution is greatly improved, and it can effectively penetrate into the deep tissue of the peanuts to complete deep hydrolysis. The end point of gradual decompression is to reduce the pressure to atmospheric pressure~4MPa. This is equivalent to reducing the pressure at a rate of approximately 50kpa / s~1000kpa / s during the decompression process, which helps to promote the separation of oil hydrolysis products and the discharge of the solution from the inside of the peanuts, while helping to promote the forward progress of the reaction and enhancing the cavitation effect, so that the oil deep inside the peanuts can be more fully hydrolyzed, thereby improving the degreasing effect.

[0047] The pH of saturated carbonate solution is 5.6. When more carbon dioxide is added under pressure, more carbonic acid will dissolve in the water according to Henry's law. After dissolving more carbonic acid, more hydrogen ions will be ionized to maintain ionization balance. Therefore, the actual pH is lower, which provides good acidic conditions for the acidic hydrolysis of oils and fats, and can significantly accelerate the hydrolysis reaction of fatty acid glycerides and improve the hydrolysis efficiency. At the same time, the acidic conditions created by carbon dioxide are milder and have fewer impurities, which is conducive to ensuring the nutrition and taste of defatted peanuts, and is suitable for a variety of food processing purposes.

[0048] In the step S3 pressure change procedure, the pressurization method is: adding carbon dioxide or a mixture of carbon dioxide and nitrogen to the circulating gas; the decompression method is: reducing the circulating gas. The combined pressurization method of carbon dioxide and nitrogen can not only maintain the acidic environment continuously, but also prevent oxygen from entering the system through the inert effect of nitrogen, reduce the risk of oxidation, and ensure the stability of the nutritional components of peanuts. Carbon dioxide not only plays a role in regulating acidity, but also is used to regulate pressure, so that the method uses less materials and is not easy to introduce other impurities, making the resulting defatted peanuts safer to eat.

[0049] Embodiment 1 Add tap water to the reaction tank until the peanut kernels placed in the reaction tank are submerged. Fill the reaction tank with carbon dioxide. Perform a pressure change procedure: heat the mixture in the reaction tank at 80°C, increase the pressure in the reaction tank to 30MPa within 30 minutes, and then reduce the pressure in the reaction tank to 4MPa within 10 minutes. Repeat the pressure change procedure for 4 rounds. While performing the pressure change procedure, continuously extract the liquid and gas in the reaction tank and re-introduce them into the reaction tank to form a continuous circulation reflux. Balance to atmospheric pressure, discharge the liquid in the reaction tank, evacuate the reaction tank to an absolute pressure of 10kpa, and heat the peanut kernels in the reaction tank at 60°C for 30 minutes. Repeat the above steps in sequence for 4 rounds to obtain defatted peanuts.

[0050] Embodiment 2 Add tap water to the reaction tank until the peanut kernels placed in the reaction tank are submerged. Fill the reaction tank with carbon dioxide. Perform the first pressure change procedure: heat the mixture in the reaction tank at 80°C, increase the pressure in the reaction tank to 10MPa within 40 minutes, and then reduce the pressure in the reaction tank to atmospheric pressure within 20 minutes. Repeat the first pressure change procedure for 2 rounds. Perform the second pressure change procedure: heat the mixture in the reaction tank at 100°C, increase the pressure in the reaction tank to 60MPa within 30 minutes, and then reduce the pressure in the reaction tank to 2MPa within 10 minutes. Repeat the second pressure change procedure for 2 rounds. While performing the pressure change procedure, continuously extract the liquid and gas in the reaction tank and re-introduce them into the reaction tank to form a continuous circulation reflux. Balance to atmospheric pressure, discharge the liquid in the reaction tank, evacuate the reaction tank to an absolute pressure of 6kpa, and heat the peanut kernels in the reaction tank at 40°C for 20 minutes. Repeat the above steps in sequence for 3 rounds to obtain defatted peanuts.

[0051] Embodiment 3 Add protective salt water to the reaction tank until the peanut kernels placed in the reaction tank are submerged. Fill the reaction tank with carbon dioxide. Execute the third pressure change procedure: heat the mixture in the reaction tank at 90°C, increase the pressure in the reaction tank to 60MPa within 40 minutes, and then reduce the pressure in the reaction tank to 1MPa within 20 minutes. Repeat the third pressure change procedure for 3 rounds. While executing the pressure change procedure, continuously extract the liquid and gas in the reaction tank and re-introduce them into the reaction tank to form a continuous circulation reflux. Balance to atmospheric pressure, discharge the liquid in the reaction tank, evacuate the reaction tank to an absolute pressure of 20kpa, and heat the peanut kernels in the reaction tank at 70°C for 10 minutes.

[0052] Add physiological saline to the reaction tank until the peanut kernels placed in the reaction tank are submerged. Fill the reaction tank with carbon dioxide. Execute the fourth pressure change procedure: heat the mixture in the reaction tank at 110°C, increase the pressure in the reaction tank to 40MPa within 30 minutes, and then reduce the pressure in the reaction tank to 4MPa within 10 minutes. Repeat the fourth pressure change procedure for 2 rounds. While executing the pressure change procedure, continuously extract the liquid and gas in the reaction tank and re-introduce them into the reaction tank to form a continuous circulation reflux. Balance to atmospheric pressure, discharge the liquid in the reaction tank, evacuate the reaction tank to an absolute pressure of 6kpa, and heat the peanut kernels in the reaction tank at 50°C for 30 minutes. Obtain defatted peanuts.

[0053] In the description of this specification, the description with reference to the terms "one embodiment", "certain embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0054] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for producing defatted peanuts, characterized in that: The following steps are involved: Add water to the reaction tank until the peanut kernels placed in the reaction tank are submerged; Filling the reaction tank with carbon dioxide in an amount such that the solution in the reaction tank is always acidic in subsequent steps; The mixture in the reaction tank is heated, the pressure in the reaction tank is gradually increased and then gradually reduced to complete a round of pressure change procedure, during which the liquid and gas in the reaction tank are continuously extracted and re-introduced into the reaction tank to form a continuous circulation reflux, and the pressure change procedure is repeated for more than two rounds; Balancing to atmospheric pressure, discharging the liquid in the reaction tank, evacuating the reaction tank and heating the peanut kernels in the reaction tank to dehydrate the peanut kernels; Repeat the above steps in order for more than two rounds to obtain the defatted peanuts.

2. The method for producing defatted peanuts according to claim 1, characterized in that: In the step of heating the mixture in the reaction tank, the heating temperature is 80° C. or higher.

3. The method for producing defatted peanuts according to claim 1, characterized in that: Each round of the voltage transformation process lasts for 40 minutes to 60 minutes.

4. The method for producing defatted peanuts according to claim 3, characterized in that: In each round of the pressure change procedure, the time taken to gradually increase the pressure in the reaction tank is 30 minutes to 40 minutes, and the time taken to gradually reduce the pressure is 10 minutes to 20 minutes.

5. The method for producing defatted peanuts according to claim 1 or 4, characterized in that: In each round of the pressure change procedure, the end point of gradually increasing the pressure in the reaction tank is to increase the pressure to 10MPa~60MPa, and the end point of gradually reducing the pressure is to reduce the pressure to atmospheric pressure~4MPa.

6. The method for producing defatted peanuts according to claim 1, characterized in that: In the pressure changing procedure, the pressure increasing method is: adding carbon dioxide or a mixture of carbon dioxide and nitrogen into the circulating gas; the pressure reducing method is: reducing the circulating gas.

7. The method for producing defatted peanuts according to claim 1, characterized in that: The requirement for evacuating the reaction tank is that the pressure inside the reaction tank is 6kPa~20kPa; the temperature for heating the peanut kernels in the reaction tank is 40℃~70℃, and the heating time is 10min~30min.

8. The method for producing defatted peanuts according to claim 1, characterized in that: In the step of adding water to the reaction tank until the peanut kernels placed in the reaction tank are submerged, salt is dissolved in the added water.

9. The method for producing defatted peanuts according to claim 1, characterized in that: In the pressure change procedure, the liquid that is reintroduced into the reaction tank enters the reaction tank from the top of the reaction tank, and the gas that is reintroduced into the reaction tank enters the reaction tank from the bottom of the reaction tank.