A method for continuously producing potassium diformate

Abstract

The present invention belongs to the field of feed additive production, and specifically relates to a method for continuously producing potassium diformate. The method is implemented by the following steps: placing potassium carbonate in a reactor, adding 85% formic acid, and conducting a mixing reaction; vacuum crystallization; centrifugal separation; recovering the mother liquor and drying it, then packaging the finished product and treating the generated tail gas. The present invention prepares a novel, green, and efficient feed additive. During the preparation process, formic acid is added in two steps, resulting in a complete reaction, improving the reaction yield, and the potassium diformate has high purity. The present invention improves the conversion rate and yield by controlling the reaction temperature and residence time during the reaction and crystallization process. The present invention uses hexadecyl ester for coating, which can effectively prevent the potassium diformate from absorbing water and decomposing, thereby improving the stability of the product.

Description

Technical Field

[0001] The invention belongs to the field of feed additive production, and particularly relates to a method for continuously producing potassium diformate. Background Art

[0002] As the disadvantages of antibiotics become more and more obvious, in order to ensure production efficiency in the breeding field, feed additives that can promote animal growth and development, reduce animal morbidity, and are non-toxic and have no side effects are receiving more and more attention.

[0003] Potassium diformate can regulate the microecological balance in the digestive tract, effectively inhibiting bacterial growth and reproduction, improving feed digestibility and conversion, and reducing gastrointestinal diseases. It is also non-toxic to animals and leaves no residue in the body. Potassium diformate holds great promise as a new alternative to antibiotic growth promoters. However, current domestic synthesis technology for potassium diformate suffers from low yields and intermittent production, hindering its large-scale production. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention provides a method for continuously producing potassium diformate.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows:

[0006] The present invention provides a method for continuously producing potassium diformate, comprising the following steps:

[0007] (1) Potassium carbonate is placed in a reactor, and 85% formic acid is added to carry out a mixing reaction;

[0008] (2) Vacuum crystallization: When the content of potassium diformate reaches a certain level, vacuum crystallization is performed to precipitate potassium diformate, and 85% formic acid is added to the vacuum crystallization for further reaction;

[0009] (3) Centrifugal separation: After crystallization is completed, the material is sent to the centrifuge, the centrifugally dehydrated material is sent to the fluidized bed dryer for drying, and the mother liquor is sent to the tank-type stirring mixer;

[0010] (4) Mother liquor recovery: After centrifugal separation, the mother liquor is stirred and transported to the reactor and crystallizer to continue the reaction;

[0011] (5) Drying: Dehydrated materials and concentrated materials from the mixer are dried with hot air;

[0012] (6) Finished product packaging: The dried potassium diformate is coated with hexadecane and then sent to the packaging machine. After measurement, it is packed in bags and sent to the finished product warehouse;

[0013] (7) Tail gas treatment: The reaction tail gas, drying tail gas and packaging tail gas are sent to the alkaline washing tower for treatment and then discharged to a safe place at high altitude.

[0014] Furthermore, in step (1), the molar ratio of potassium carbonate to formic acid is 1:2.5.

[0015] Furthermore, in step (1), the reactor is a stirred anti-sticking reactor, and the stirrer speed is controlled at a low speed of 75 rpm; the temperature of the mixing reaction is 55-60° C., and the reaction is carried out for 2 hours.

[0016] Furthermore, in step (2), when the potassium diformate content reaches 60%, it is sent to a vacuum crystallizer; the conditions for the vacuum crystallization are: maintaining a negative pressure of 2 kPa, room temperature, and a residence time of 1 hour; during the vacuum crystallization process, 85% formic acid solution with a molar ratio of 0.5 to potassium carbonate is continuously added.

[0017] Furthermore, in step (4), the stirring speed is 88 rpm.

[0018] Furthermore, in step (5), the hot air drying is performed by using a 1KPa hot air blower to deliver 80°C air heated by 0.8Mpa steam as a heat source.

[0019] Furthermore, in step (6), the content of hexadecyl fat in the finished product is 1-2%.

[0020] The potassium diformate production process provided by the present invention mainly includes a potassium diformate synthesis step, a vacuum crystallization step, a centrifugal separation step, a mother liquor recovery step, a fluidized bed drying step, a product packaging step, and an exhaust gas treatment step. Its main equipment includes a raw material silo, a fan filter, an exhaust gas fan, a reactor, a vacuum crystallizer, a slurry pump, a circulating cooler, a stirring mixer, a mother liquor pump, a dryer spray pump, a fluidized bed dryer, a vibrating screen, a crusher, a coating device, a cooler, an elevator, a product silo, a blast tank, a packaging machine, a fan filter, a fan, an air heater, an alkali washing tower, etc.

[0021] The beneficial effects achieved by the present invention are:

[0022] (1) The present invention prepares a novel, green, and efficient feed additive. During the preparation process, formic acid is added twice, the reaction is complete, the reaction yield is improved, and the purity of potassium diformate is high;

[0023] (2) The present invention improves the conversion rate and yield by controlling the reaction temperature and residence time during the reaction and crystallization process;

[0024] (3) The present invention uses hexadecane for coating, which can effectively prevent the water absorption and decomposition of potassium diformate and improve the stability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1This is a schematic diagram of a potassium diformate process route;

[0026] Among them, 1 is the raw material silo, 2 is the fan filter, 3 is the exhaust fan, 4 is the reactor, 5 is the vacuum crystallizer, 6 is the slurry pump, 7 is the circulating cooler, 8 is the stirring mixer, 9 is the centrifuge, 10 is the tank stirring mixer, 11 is the mother liquor pump, 12 is the dryer spray pump, 13 is the fluidized bed dryer, 14 is the vibrating screen, 15 is the crusher, 16 is the coating device, 17 is the cooler, 18 is the crusher, 19 is the elevator, 20 is the product silo, 21 is the blast tank, 22 is the packaging machine, 23 is the fan filter, 24 is the fan, 25 is the air heater, 26 is the fan filter, 27 is the fan, 28 is the air cooler, 29 is the fan filter, 30 is the fan, and 31 is the alkali washing tower. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further explained and illustrated by means of specific embodiments below.

[0028] Example 1

[0029] (1) Synthesis of potassium diformate: Potassium carbonate is pneumatically conveyed to the raw material silo and released to the reactor through a star valve. 85% formic acid is pumped to the reactor through a pipeline. Potassium carbonate (calculated as potassium) and formic acid are mixed and reacted in the reactor at a molar ratio of 1:2.5 under the action of an agitator. The materials circulate in the reactor for 2 hours. Carbon dioxide is generated during the process, containing a small amount of formic acid waste gas. This tail gas carries away part of the reaction heat and is treated in an alkali liquid tower. The reaction temperature is strictly controlled below 60°C, and the reaction temperature is controlled by the tail gas and the cooling reflux slurry.

[0030] (2) Vacuum crystallization: When the potassium diformate content reaches 60%, it is sent to a vacuum crystallizer to precipitate potassium diformate. The vacuum crystallizer is maintained at a negative pressure of 2KPa and room temperature for 1 hour. 85% formic acid at a molar ratio of 0.5 (to potassium carbonate) is added to the vacuum crystallizer for further reaction. (3) Centrifugal separation: After crystallization is completed, the material is sent to a centrifuge. The centrifugally dehydrated material is sent to a fluidized bed dryer for drying, and the mother liquor is sent to a tank-type stirring mixer.

[0031] (4) Mother liquor recovery: After centrifugal separation, the mother liquor is transported to the reactor and crystallizer through a tank-type stirring mixer at a stirring speed of 88 rpm to continue the reaction.

[0032] (5) Fluidized bed drying: The dehydrated material and the concentrated material of the mixer are dried with hot air in the fluidized bed dryer. The 1KPa hot air blower delivers 80℃ air heated by 0.8Mpa steam as the heat source of the dryer.

[0033] (6) Finished product packaging: The dried potassium diformate is coated with hexadecane and sent to the packaging machine. After measurement, it is packed in bags and sent to the finished product warehouse.

[0034] (7) Tail gas treatment: The reaction tail gas, drying tail gas and packaging tail gas are sent to the alkaline washing tower for treatment and then discharged to a safe place at high altitude.

[0035] The production process of potassium diformate with an annual output of 3,000 tons requires 2,130 tons of 85% formic acid, 1,620 tons of 99% potassium carbonate, 45 tons of cetyl ester, a reactor diameter of 2 meters, a crystallizer diameter of 1.5 meters, and a fluidized bed dryer of 10 tons / hour in the form of spray drying.

[0036] Comparative Example 1

[0037] (1) Synthesis of potassium diformate: Potassium carbonate is pneumatically conveyed to the raw material silo and released to the reactor through a star valve. 85% formic acid is pumped to the reactor through a pipeline. Potassium carbonate (calculated as potassium) and formic acid solution are mixed and reacted in the reactor under the action of a stirrer at a molar ratio of 1:3. The materials circulate in the reactor for 2 hours. Carbon dioxide is generated during the process, containing a small amount of formic acid waste gas. This tail gas carries away part of the reaction heat and is treated in an alkali liquid tower. The reaction temperature is strictly controlled below 60°C, and the reaction temperature is controlled by the tail gas and the cooling reflux slurry.

[0038] (2) Vacuum crystallization: When the potassium diformate content reaches 60%, it is sent to a vacuum crystallizer to precipitate potassium diformate. The vacuum crystallizer is maintained at a negative pressure of 2KPa and room temperature for 1 hour.

[0039] Steps (3) to (7) are the same as in Example 1.

[0040] Comparative Example 2

[0041] (1) Synthesis of potassium diformate: Potassium carbonate is pneumatically conveyed to the raw material silo and released to the reactor through a star valve. 85% formic acid is pumped to the reactor through a pipeline. Potassium carbonate and formic acid solution are mixed and reacted in the reactor at a molar ratio of 1:2.5 under the action of an agitator. The materials circulate in the reactor for 2 hours. Carbon dioxide is generated during the process, containing a small amount of formic acid waste gas. This tail gas carries away part of the reaction heat and is treated in an alkali liquid tower. The reaction temperature is strictly controlled below 60°C, and the reaction temperature is controlled by the tail gas and the cooling reflux slurry.

[0042] (2) Room temperature crystallization: When the potassium diformate content reaches 60%, crystallization is carried out at room temperature under stirring conditions for 25 hours. During the room temperature crystallization process, 85% formic acid with a molar ratio of 0.5 (to potassium carbonate) is continuously added for further reaction.

[0043] (3) Centrifugal separation: After crystallization is completed, the material is sent to the centrifuge. The material after centrifugal dehydration is sent to the fluidized bed dryer for drying, and the mother liquor is sent to the tank stirring mixer.

[0044] (4) Mother liquor recovery: After centrifugal separation, the mother liquor is transported to the reactor and crystallizer through a tank-type stirring mixer at a stirring speed of 88 rpm to continue the reaction.

[0045] (5) Fluidized bed drying: The dehydrated material and the concentrated material of the mixer are dried with hot air in the fluidized bed dryer. The 1KPa hot air blower delivers 80℃ air heated by 0.8Mpa steam as the heat source of the dryer.

[0046] (6) Finished product packaging: The dried potassium diformate is coated with hexadecane and sent to the packaging machine. After measurement, it is packed in bags and sent to the finished product warehouse.

[0047] (7) Tail gas treatment: The reaction tail gas, drying tail gas and packaging tail gas are sent to the alkaline washing tower for treatment and then discharged to a safe place at high altitude.

[0048] Effect embodiment

[0049] The yield, purity, energy consumption and crystal form of the potassium diformate prepared in the examples and comparative examples were calculated and counted. The specific results are shown in Table 1.

[0050] Table 1

[0051]

Claims

1. A method for continuously producing potassium diformate, characterized in that: The following steps are involved: (1) Potassium carbonate is placed in a reactor, and 85% formic acid is added to carry out a mixing reaction; (2) Vacuum crystallization: When the content of potassium diformate reaches a certain level, vacuum crystallization is performed to precipitate potassium diformate, and 85% formic acid is added to the vacuum crystallization for further reaction; (3) Centrifugal separation: After crystallization is completed, the material is sent to the centrifuge, the centrifugally dehydrated material is sent to the fluidized bed dryer for drying, and the mother liquor is sent to the tank-type stirring mixer; (4) Mother liquor recovery: After centrifugal separation, the mother liquor is stirred and transported to the reactor and crystallizer to continue the reaction; (5) Drying: Dehydrated materials and concentrated materials from the mixer are dried with hot air; (6) Finished product packaging: The dried potassium diformate is coated with hexadecane and then sent to the packaging machine. After measurement, it is packed in bags and sent to the finished product warehouse; (7) Tail gas treatment: The reaction tail gas, drying tail gas and packaging tail gas are sent to the alkali washing tower for treatment and then discharged to a safe place at high altitude; In step (1), the molar ratio of potassium carbonate to formic acid is 1:2.5; In step (2), when the potassium diformate content reaches 60%, it is sent to a vacuum crystallizer; the conditions for the vacuum crystallization are: maintaining a negative pressure of 2 kPa, room temperature, and a residence time of 1 hour; during the vacuum crystallization process, 85% formic acid solution with a molar ratio of 0.5 to potassium carbonate is continuously added.

2. The method according to claim 1, characterized in that In step (1), the reactor is a stirred anti-sticking reactor, and the stirrer speed is controlled at a low speed of 75 rpm; the temperature of the mixing reaction is 55-60°C, and the reaction is carried out for 2 hours.

3. The method according to claim 1, characterized in that In step (4), the stirring speed is 88 rpm.

4. The method according to claim 1 or 3, characterized in that In step (5), the hot air drying is carried out by using a 1KPa hot air blower to deliver 80°C air heated by 0.8Mpa steam as a heat source.

5. The method according to claim 1, wherein In step (6), the content of hexadecane in the finished product is 1-2%.

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