A method for producing high-gas velocity sodium dihydrogen pyrophosphate

Abstract

The present application relates to the production of pyrophosphate sodium, and discloses a method for producing high-gas-speed pyrophosphate sodium, comprising the following steps: neutralization, spray drying, polymerization, acid spraying and cooling, crushing, screening and packaging, to obtain high-gas-speed pyrophosphate sodium. The method comprises the following steps: neutralizing food phosphoric acid and alkali to obtain sodium phosphate slurry, controlling the specific gravity to 1.4-1.6 and pH to 4.0-4.3; conveying the neutralized slurry to a spray drying tower for drying, controlling the tower bottom temperature to 145-160 DEG C; drying the powder and then putting it into a dynamic polymerization furnace for polymerization, to form ordinary-gas-speed pyrophosphate sodium. The powder is put into a cooling roller from the polymerization furnace tail, and a phosphoric acid solution is sprayed at the roller inlet, and then the pyrophosphate sodium is cooled, crushed and screened, to obtain high-gas-speed pyrophosphate sodium. The gas speed of the obtained pyrophosphate sodium is 38-42.

Description

Technical Field

[0001] This invention relates to a method for producing sodium dihydrogen pyrophosphate with a high gas evolution rate. Background Technology

[0002] Disodium dihydrogen pyrophosphate is primarily used as an acidic leavening agent in food processing. It reacts with sodium bicarbonate to produce CO2, giving baked goods a specific volume, porosity, and structure. Disodium dihydrogen pyrophosphate is categorized by its gas generation rate into high-speed (ROR40), medium-speed (ROR28), and low-speed (ROR15) grades, with high-gas-generating disodium dihydrogen pyrophosphate seeing increasingly wider applications and demand in baked goods. Current production technologies for high-gas-generating disodium dihydrogen pyrophosphate mainly increase the gas generation rate by adjusting parameters in the neutralization process, such as introducing potassium ions as solubilizing agents and lowering the pH of the neutralization slurry. Pre-hydration treatment of the ROR28 grade product is also used to improve solubility, thereby increasing the gas generation rate. A common problem is that the introduction of potassium salts leads to hygroscopicity, and pre-hydration treatment also increases product humidity, making the disodium dihydrogen pyrophosphate prone to clumping during storage, which is detrimental to its use. Lowering the pH of the neutralization slurry combined with controlling the polymerization temperature has a limited temperature control range, which is not conducive to large-scale industrial production.

[0003] To address the shortcomings of existing technologies, this invention provides a method for producing high-gas-generating disodium dihydrogen pyrophosphate. Using conventional processes, ordinary disodium dihydrogen pyrophosphate is obtained from the polymerization furnace tail. After acid treatment, a layer of phosphate molecules coats the surface of the disodium dihydrogen pyrophosphate molecules, imparting more H+ ions and enhancing its gas-generating activity. This method is simple and easy to operate. Utilizing the high temperature of the material exiting the polymerization furnace tail, excess moisture is dried during the cooling process. Simultaneously, the phosphate molecules coat the disodium dihydrogen pyrophosphate, preventing it from absorbing moisture, which helps maintain stability during storage. The main content, water-insoluble matter, and gas-generating rate of the product remain unaffected. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides the following technical solution: a high-speed method for producing disodium dihydrogen pyrophosphate, comprising the following steps: neutralization, spray drying, polymerization, acid spray cooling, crushing, sieving, and packaging.

[0005] Preferably, the neutralization process involves adding food-grade phosphoric acid, water, and alkali (containing sodium carbonate and / or sodium hydroxide) to a neutralization pot, reacting at a temperature of 90-100°C, controlling the pH of the neutralized solution to 4.0-4.3, and controlling the specific gravity to 1.4-1.6 to obtain a sodium dihydrogen phosphate slurry.

[0006] Preferably, the spray drying process involves: injecting the neutralized liquid into a spray drying tower via a high-pressure pump, with the bottom temperature of the tower being 145℃~160℃, to obtain anhydrous sodium dihydrogen phosphate powder.

[0007] Preferably, the polymerization process involves feeding the dried anhydrous sodium dihydrogen phosphate powder into a polymerization furnace, ensuring the furnace tail temperature is 180℃~210℃, and the powder reacting in the furnace for 30~50 minutes. Samples of the material exiting the polymerization furnace are taken and tested using the silver nitrate method to determine if they meet the requirements, yielding crude disodium dihydrogen pyrophosphate.

[0008] Preferably, in the acid spraying cooling process: the high-temperature material flowing out of the furnace tail enters the cooling drum, and an atomizing nozzle is installed at the head of the drum to spray a room-temperature phosphoric acid solution onto the material, controlling the pH of the disodium dihydrogen pyrophosphate at the tail of the cooling drum to 3.8-3.9. The mass concentration of the phosphoric acid solution is 85-90%, and the acid spraying temperature is 25-30℃.

[0009] Preferably, as notified in the art, the obtained disodium dihydrogen pyrophosphate undergoes a crushing, sieving, and packaging process: the cooled disodium dihydrogen pyrophosphate is crushed, sieved, and then packaged.

[0010] Preferably, the high-gas-emission disodium dihydrogen pyrophosphate has a sampling ROR value between 38 and 42.

[0011] Compared with the prior art, the present invention provides a method for producing disodium dihydrogen pyrophosphate with a high gas evolution rate, comprising the following:

[0012] Beneficial effects:

[0013] The sodium dihydrogen pyrophosphate obtained by this method has a pH of 3.8-3.9 and a gas evolution rate of 38-42. The neutralization, drying, and polymerization processes of this method employ conventional operations, especially since the temperature does not require stringent control, reducing process complexity and facilitating higher yield and stability in large-scale continuous production. Physical acidification is added to the crude sodium dihydrogen pyrophosphate exiting the polymerization furnace, causing some phosphate molecules to coat the surface of the sodium dihydrogen pyrophosphate molecules, resulting in a final product with more H+. + This increases the reaction rate with sodium bicarbonate. In addition, the crude sodium dihydrogen pyrophosphate coming out of the polymerization furnace has a high temperature (about 180°C). After acid spraying, the phosphoric acid solution is evenly coated on the surface of the sodium dihydrogen pyrophosphate, which can dry out excess moisture with its own high temperature. The product is moisture-free and can also solve the problem of moisture absorption and clumping. Detailed Implementation

[0014] The technical solution of the present invention will be described in detail below with reference to the embodiments of the present invention.

[0015] It is worth noting that the following embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention should be determined by the content of the claims. Modifications and equivalent substitutions made by those skilled in the art without creative effort, provided they fully understand the technical solution of the present invention, all fall within the scope of protection of the present invention.

[0016] Example 1

[0017] S1. Neutralization: Add food-grade phosphoric acid, water, and alkali (sodium carbonate and / or sodium hydroxide) to a neutralization vessel and react at a temperature of 90-100℃. Control the endpoint to a pH of 4.1 and a specific gravity of 1.55 to obtain a sodium dihydrogen phosphate slurry.

[0018] S2. Spray drying: The neutralized slurry is pumped into the spray drying tower through a high-pressure pump. The temperature at the bottom of the tower is 145℃~160℃ to obtain anhydrous sodium dihydrogen phosphate powder.

[0019] S3. Polymerization: Anhydrous sodium dihydrogen phosphate powder is fed into a polymerization furnace. The furnace tail temperature is 190℃~210℃, and the powder reacts in the furnace for 40 minutes. Samples of the furnace tail material are taken and the main content is determined by the silver nitrate method to be within acceptable limits, yielding crude disodium dihydrogen pyrophosphate.

[0020] S4. Acid spray cooling: The high-temperature material at the tail of the furnace flows into the cooling drum. The atomizing nozzle at the head of the drum is turned on to spray the material with an 85% phosphoric acid solution, which is 8% of the weight of the crude product disodium dihydrogen pyrophosphate. The pH of the material is controlled at 3.8. The material flows out after being cooled by the cooling drum.

[0021] S5. Crushing, screening and packaging process: The cooled sodium dihydrogen pyrophosphate is crushed, screened and then packaged.

[0022] Final product analysis: main content 96.3%, pH 3.80; water-insoluble matter 0.02%, gas evolution rate 42, moisture content 0.01%, product is stable during storage and does not easily absorb moisture, after one year the moisture content is 0.04%, main content 95.5%, pH 3.75, gas evolution rate 41.

[0023] Example 2

[0024] S1. Neutralization: Add food-grade phosphoric acid, water, and alkali (sodium carbonate and / or sodium hydroxide) to a neutralization vessel and react at a temperature of 90-100℃. Control the endpoint to a pH of 4.1 and a specific gravity of 1.55 to obtain a sodium dihydrogen phosphate slurry.

[0025] S2. Spray drying: The neutralized slurry is pumped into the spray drying tower through a high-pressure pump. The temperature at the bottom of the tower is 145℃~160℃ to obtain anhydrous sodium dihydrogen phosphate powder.

[0026] S3. Polymerization: Anhydrous sodium dihydrogen phosphate powder is fed into a polymerization furnace. The furnace tail temperature is 190℃~210℃, and the powder reacts in the furnace for 40 minutes. Samples of the furnace tail material are taken and the main content is determined by the silver nitrate method to be within acceptable limits, yielding crude disodium dihydrogen pyrophosphate.

[0027] S4. Acid spray cooling: The high-temperature material at the tail of the furnace flows into the cooling drum. The atomizing nozzle at the head of the drum is turned on to spray the material with a 90% phosphoric acid solution, which is 5% of the weight of the crude disodium pyrophosphate. The pH of the material is controlled at 3.9. The material flows out after being cooled by the drum.

[0028] S5. After cooling, the disodium dihydrogen pyrophosphate is crushed, sieved, and then packaged.

[0029] Final product analysis: main content 96.5%, pH 3.93; water-insoluble matter 0.03%, gas evolution rate 39. Moisture content 0.01%, product is relatively stable during storage, after one year moisture content 0.05%, main content 95.2%, pH 3.82, gas evolution rate 40.

[0030] Example 3

[0031] S1. Neutralization: Add food-grade phosphoric acid, water, and alkali (sodium carbonate and / or sodium hydroxide) to a neutralization vessel and react at a temperature of 90-100℃. Control the endpoint to a pH of 4.1 and a specific gravity of 1.55 to obtain a sodium dihydrogen phosphate slurry.

[0032] S2. Spray drying: The neutralized slurry is pumped into the spray drying tower through a high-pressure pump. The temperature at the bottom of the tower is 145℃~160℃ to obtain anhydrous sodium dihydrogen phosphate powder.

[0033] S3. Polymerization: Anhydrous sodium dihydrogen phosphate powder is fed into a polymerization furnace. The furnace tail temperature is 190℃~210℃, and the powder reacts in the furnace for 40 minutes. Samples of the furnace tail material are taken and the main content is determined by the silver nitrate method to be within acceptable limits, yielding crude disodium dihydrogen pyrophosphate.

[0034] S4. Acid spray cooling: The high-temperature material at the tail of the furnace flows into the cooling drum. The atomizing nozzle at the head of the drum is turned on to spray the material with a 75% phosphoric acid solution, which is 8% of the weight of the crude product disodium dihydrogen pyrophosphate. The pH of the material is controlled at 3.95. The material flows out after being cooled by the drum.

[0035] S5. After cooling, the disodium dihydrogen pyrophosphate is crushed, sieved, and then packaged.

[0036] Final product analysis: main content 96.5%, pH 3.95; water-insoluble matter 0.03%, gas evolution rate 36. Moisture content 0.02%, after one year of storage the moisture content is 0.18%, main content 91.62%, pH 4.16, gas evolution rate 38.

[0037] Example 4

[0038] S1. Neutralization: Add food-grade phosphoric acid, water, and alkali (sodium carbonate and / or sodium hydroxide) to a neutralization vessel and react at a temperature of 90-100℃. Control the endpoint to a pH of 4.1 and a specific gravity of 1.55 to obtain a sodium dihydrogen phosphate slurry.

[0039] S2. Spray drying: The neutralized slurry is pumped into the spray drying tower through a high-pressure pump. The temperature at the bottom of the tower is 145℃~160℃ to obtain anhydrous sodium dihydrogen phosphate powder.

[0040] S3. Polymerization: Anhydrous sodium dihydrogen phosphate powder is fed into a polymerization furnace. The furnace tail temperature is 190℃~210℃, and the powder reacts in the furnace for 40 minutes. Samples of the furnace tail material are taken and the main content is determined by the silver nitrate method to be within acceptable limits, yielding crude disodium dihydrogen pyrophosphate.

[0041] S4. Acid spray cooling: The high-temperature material at the tail of the furnace flows into the cooling drum. The atomizing nozzle at the head of the drum is turned on to spray the material with a 40% phosphoric acid solution, which is 8% of the weight of the crude product disodium dihydrogen pyrophosphate. The pH of the material is controlled at 3.95. The material flows out after being cooled by the drum.

[0042] S5. After cooling, the disodium dihydrogen pyrophosphate is crushed, sieved, and then packaged.

[0043] Final product analysis: main content 92.73%, pH 3.90; water-insoluble matter 0.08%, gas evolution rate 37. Moisture content 0.02%, after one year of storage the moisture content is 0.36%, main content 89.95%, pH 4.25, gas evolution rate 38.

[0044] Comparative Example 1

[0045] S1. Neutralization: Add food-grade phosphoric acid, water, and alkali (sodium carbonate and / or sodium hydroxide) to a neutralization vessel and react at a temperature of 90-100℃. Control the endpoint to a pH of 4.1 and a specific gravity of 1.55 to obtain a sodium dihydrogen phosphate slurry.

[0046] S2. Spray drying: The neutralized slurry is pumped into the spray drying tower through a high-pressure pump. The temperature at the bottom of the tower is 145℃~160℃ to obtain anhydrous sodium dihydrogen phosphate powder.

[0047] S3. Polymerization: Anhydrous sodium dihydrogen phosphate powder is fed into a polymerization furnace. The furnace tail temperature is 190℃~210℃, and the powder reacts in the furnace for 40 minutes. Samples of the furnace tail material are taken and the main content is determined by the silver nitrate method to be within acceptable limits, yielding crude disodium dihydrogen pyrophosphate.

[0048] S4. Cooling: The high-temperature material at the tail of the furnace flows into the cooling drum and flows out after being cooled.

[0049] S5. After cooling, the disodium dihydrogen pyrophosphate is crushed, sieved, and then packaged.

[0050] Final product analysis: main content 96.7%, pH 4.09; water-insoluble matter 0.04%, gas evolution rate 28. Moisture content 0.19%, after one year of storage, moisture content 0.45%, main content 86.55%, pH 4.44, gas evolution rate 35, poor stability during storage.

[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for producing disodium dihydrogen pyrophosphate with a high gas evolution rate, characterized in that, Includes the following steps: Neutralization process: Phosphoric acid, water and alkali are mixed and reacted to obtain sodium dihydrogen phosphate slurry, wherein the alkali is sodium carbonate and / or sodium hydroxide; Spray drying process: Sodium dihydrogen phosphate slurry is spray dried to obtain anhydrous sodium dihydrogen phosphate powder; Polymerization process: The dried anhydrous sodium dihydrogen phosphate powder is subjected to a polymerization reaction at 180℃~210℃ to obtain crude disodium dihydrogen pyrophosphate. Acid spray cooling: Crude disodium dihydrogen pyrophosphate flows into a cooling drum. A room-temperature phosphoric acid solution is sprayed onto the material using an atomizing nozzle. The pH of the material at the drum outlet is controlled at 3.8-3.

9. After being cooled by the cooling drum, the material flows out to obtain the product. The mass concentration of the phosphoric acid solution is 85-90%, and the acid spraying temperature is 25-30℃. The resulting disodium dihydrogen pyrophosphate has a pH of 3.8-3.9 and a gas evolution rate of 38-42.

2. The method for producing disodium dihydrogen pyrophosphate with high gas evolution rate according to claim 1, characterized in that: The neutralization reaction occurs at a temperature of 90-100℃, a pH of 4.0-4.3, and a specific gravity of 1.4-1.

6.

3. The method for producing disodium dihydrogen pyrophosphate with high gas evolution rate according to claim 1, characterized in that: During spray drying, the drying temperature is 145-160℃.