An atomizing flash dryer and a solvent removal system for surfactants

Abstract

The present invention discloses an injection flash dryer and a solvent removal system for surfactants; the injection flash dryer includes an injection cylinder body, an upper head is fixed at the upper end of the injection cylinder body, and a first distribution plate, a first injector, a second distribution plate and a second injector are arranged inside the injection cylinder body; the upper head and the first injector are connected by a flange, and the first distribution plate is clamped between the two; the first injector and the second injector are connected by a flange, and the second distribution plate is clamped between the two; small holes are respectively arranged on the first distribution plate and the second distribution plate; injection pipes are respectively arranged inside the first injector and the second injector, and air inlet holes are arranged on the injection pipes; the lower end of the injection cylinder body is connected to a gas-solid separation tank by a flange. The solvent removal system for surfactants of the present invention utilizes the relationship between the boiling point and evaporation pressure of the volatile solvent to prevent the temperature from being too low caused by the endothermic vaporization, which may lead to pipeline blockage.

Description

Technical Field

[0001] The invention relates to a jet flash drier, which is particularly suitable for a process for removing a surfactant in a solid form after drying containing a low-boiling point volatile solvent. Background Art

[0002] The production of pharmaceutical excipients often requires the use of some dangerous solvents, and these solvents must be removed in the final product preparation. At present, the most commonly used removal method is to heat the tower kettle or flash evaporate through a circulating heat exchanger, which is inefficient, takes a long time, and easily causes the finished product to deteriorate. The change in the state of the material during the removal process makes the process impossible to carry out, or the removal is not thorough. Some materials become solid after removal and are not used.

[0003] The current process for the production of solid cetostearyl sulfate is to first produce 20-30% monomers and then perform hot air spray drying. The industrialized production process consumes a lot of energy, has a low yield, and has unstable quality. If the 70% monomer with a lower water content is prepared first and then dried, the material cannot be transported because of its poor fluidity. If some volatile solvents are added during the neutralization of the 70% monomer, the fluidity will improve.

[0004] In the industrial production process of MES, 20-40% methanol needs to be added to prevent the formation of disodium salt; in addition, the addition of methanol can maintain the good fluidity of MES monomer. The final drying process must remove solvents such as ethanol and methanol.

[0005] The drying of the above materials generally uses hot air as a heat source. The relative humidity of the air is very low under high temperature, and the purpose of drying is achieved by transferring the volatiles in the wet materials into the air. However, air and organic solvents are prone to form explosive mixtures, which are highly dangerous. Summary of the invention

[0006] The purpose of the present invention is to address the defects of current manufacturing processes and manufacturing equipment, and to propose a jet flash dryer and a surfactant solvent removal system comprising the jet flash dryer, which utilizes the relationship between the boiling point and evaporation pressure of the volatile solvent to efficiently transfer the energy in the steam to the monomer material, and controls the vaporization rate of the solvent by controlling the jet steam flow rate to prevent the temperature from being too low due to the heat absorption of vaporization, thereby causing pipeline blockage. In addition, high-pressure steam can also be used as a power source to ensure that the mixture of non-volatile matter and volatile gas is in a sulfurized state, thereby achieving the purpose of fast and efficient flash evaporation.

[0007] The technical solution adopted by the present invention is:

[0008] A jet flash dryer comprises a jet cylinder, an upper end of which is fixed with an upper head, on which a feed port is provided; a first distribution plate, a first ejector, a second distribution plate and a second ejector are provided inside the jet cylinder; the upper head and the first ejector are connected by a flange, with the first distribution plate sandwiched therebetween; the first ejector and the second ejector are connected by a flange, with the second distribution plate sandwiched therebetween; small holes are provided on the first distribution plate and the second distribution plate respectively; jet pipes are provided in the first ejector and the second ejector respectively, and air inlet holes are provided on the jet pipes; the lower end of the jet cylinder is connected to a gas-solid separation tank by a flange; and air inlet port 1 and air inlet port 2 are provided on the side surface of the upper end of the jet cylinder.

[0009] The present invention also discloses a surfactant solvent removal system, comprising the aforementioned jet flash dryer, and also comprising a neutralization system, a feed pump, a preheater, a heat circulation pump and a discharge extruder; the discharge port of the neutralization system is connected to the lower feed port of the preheater through the feed pump; the upper discharge port of the preheater is divided into two paths, one path is connected to the lower feed port of the preheater through the heat circulation pump, and a check valve is provided on the pipeline; the other path is connected to the feed port of the jet flash dryer, and a back pressure valve is provided on the pipeline; the lower end of the jet flash dryer is connected to the discharge extruder.

[0010] The sparging gas used can be steam, hot compressed air or nitrogen. This can be varied depending on the hazardousness of the volatile solvent.

[0011] Furthermore, the outlet at the top of the gas-solid separation tank is connected to an exhaust system, and the exhaust system used varies according to the different injection gases. A vacuum pump can be used for steam, and a centrifugal fan can be used for non-condensable gases to maintain a negative pressure state in the gas-solid separator.

[0012] After adopting the above technical solution, the beneficial effects of the present invention are:

[0013] 1. It is suitable for flash drying of volatile solvents, especially for materials with high freezing points, such as cetostearyl sulfate, cetostearyl fatty acid methyl ester sulfonate, cetostearyl olefin sulfonate, and cetostearyl benzene sulfonate.

[0014] 2. Suitable for drying high-concentration materials, energy-saving and environmentally friendly.

[0015] 3. The manufacturing process is highly safe. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a connection schematic diagram of the solvent removal system of the present invention.

[0017] In the figure: 1-neutralization system, 2-feed pump, 3-preheater, 4-heat circulation pump, 5-check valve, 6-back pressure valve, 7-jet flash dryer, 8-discharging extruder, 9-exhaust system.

[0018] Figure 2 It is a structural schematic diagram of the jet flash dryer of the present invention;

[0019] The jet flash dryer includes: 70-feed port, 71-upper head, 72-first distribution plate, 73-first ejector, 731-injection pipe, 732-air inlet, 74-second distribution plate, 75-second ejector, 76-air inlet 1, 77-air inlet 2, 78-discharge port, 79-gas-solid separation tank. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings.

[0021] Example 1

[0022] like Figure 2 As shown: A jet flash dryer comprises a jet cylinder, an upper end of which is fixed with an upper head 71, on which a feed port 70 is provided; a first distribution plate 72, a first ejector 73, a second distribution plate 74 and a second ejector 75 are provided inside the jet cylinder; the upper head 71 and the first ejector 73 are connected by a flange, with the first distribution plate 72 sandwiched therebetween. The first ejector 73 and the second ejector 75 are connected by a flange, with the second distribution plate 74 sandwiched therebetween. Small holes are provided on the first distribution plate and the second distribution plate, respectively; injection pipes 731 are provided in the first ejector and the second ejector, respectively, and air inlet holes 732 are provided on the injection pipes; the lower end of the jet cylinder is connected to a gas-solid separation tank 79 via a flange.

[0023] In the jet flash dryer 7, 70% of the slurry material flows into the upper head 71 from the upper feed port 70. Due to the flow limiting effect of the small holes on the first distribution plate 72, the fluid is evenly distributed through the small holes on the first distribution plate 72 and sprayed into the first injector 73. Each small hole is connected to a spray pipe. Since the small hole has a small cross-sectional area and a fast flow rate, the flow rate of the material drops rapidly after being sprayed into the spray pipe, and the volatile solvent evaporates and absorbs heat, causing the material temperature in the spray pipe to drop sharply. The upper end side of the jet cylinder is provided with an air inlet 1 76 and an air inlet 2 77. There are many vertically arranged injection pipes inside the first injector 73, and there is an air inlet at the top of each injection pipe. Steam enters the air inlet of the injection pipe from the air inlet 1 76, and is mixed and heated with the monomer sprayed from the small holes on the first distribution plate to prevent the material temperature from dropping sharply and clogging the injection pipe. The mixed and heated monomer material moves downward through the small holes on the second distribution plate 74 and is sprayed into the second injector 75.

[0024] The internal structure of the second injector 75 is the same as that of the first injector 73, except that the diameter of the injection pipe and the diameter of the air inlet hole inside the second injector 75 are larger than those of the injection pipe in the first injector 73. After secondary mixing and heating, the monomer and steam flow out to the gas-solid separation tank 79 through the discharge port 78, and the volatile gas and the high-temperature molten material are separated. The second injector 75 and the gas-solid separation tank 79 are tightly connected by a flange. The volatile gas is sucked away by the exhaust system 9 through the outlet at the top of the gas-solid separation tank 79. The high-temperature molten material falls to the bottom of the gas-solid separation tank 79 and is output through the discharge extruder 8 for further processing.

[0025] Example 2

[0026] like Figure 1 As shown, a surfactant solvent removal system comprises the aforementioned jet flash dryer 7, and also comprises a neutralization system 1, a feed pump 2, a preheater 3, a heat circulation pump 4 and a discharge extruder 8; the discharge port of the neutralization system 1 is connected to the lower feed port of the preheater 3 through the feed pump 2; the upper discharge port of the preheater is divided into two paths, one path is connected to the lower feed port of the preheater 3 through the heat circulation pump 4, and a check valve 5 is provided on the pipeline; the other path is connected to the feed port 70 of the jet flash dryer 7, and a back pressure valve 6 is provided on the pipeline; the lower end of the jet flash dryer 7 is connected to the discharge extruder 8.

[0027] The acid ester from sulfonation, liquid alkali and solvent react in the neutralization system 1 to obtain high-concentration monomers. The materials in the neutralization system are transported by the feed pump 2 and mixed with the hot materials transported by the circulation pump 4, and are transported to the lower feed port of the preheater 3 for heating, and flow out from the upper discharge port of the preheater, and are divided into two paths. One path circulates through the heat circulation pump 4 and returns to the feed port of the preheater through the check valve 5; the other path is transported to the feed port 70 of the jet flash dryer 7 after the pressure is controlled by the back pressure valve 6.

[0028] In the material preheating system, the material is circulated and heated through the heat circulation pump 4 and the preheater 3, mainly to prevent uneven distribution of material flow rate, slow flow rate, long residence time and other factors from causing material deterioration, blocking the pipeline, and heat cannot be efficiently transferred to the monomer material. Flow rate of hot circulating material: material delivered by the feed pump = (5-10): 1. The back pressure varies according to the boiling point of the solvent. In principle, the back pressure is higher than the saturated vapor pressure of the heated material. The vapor pressure generally does not exceed 1.0MPa. While ensuring the quality of the material, increasing the heating temperature can effectively prevent the temperature drop caused by the jet flash from clogging the jet pipe.

[0029] The monomer material is dried by two-stage jet flash evaporation. This can prevent the incomplete flash evaporation caused by insufficient heating energy of the preheater, which causes the monomer temperature to be too low and causes pipeline blockage. It can also control the flash pressure by controlling the diameter of the jet pipe to prevent excessive flash evaporation and increase the mixed heating effect of steam and monomer material. The secondary flash evaporation is to continue to supplement energy on the basis of the primary flash evaporation to fully volatilize the volatile solvent in the monomer material and achieve the purpose of drying.

[0030] The sparging gas used can be steam, hot compressed air or nitrogen. This can be varied depending on the hazardousness of the volatile solvent.

[0031] Here’s how it works:

[0032] The first step is to circulate heating back pressure;

[0033] The acid ester, liquid alkali and solvent react in the neutralization system 1 to generate a slurry monomer containing a volatile solvent, which is metered by the feed pump 2 and mixed with the circulating hot material and transported to the preheater 3 for heating. The main purpose of circulating the hot material is to maintain a certain flow rate of the material to prevent the material from having a low flow rate in the preheater and causing deterioration. The material temperature rises during the preheating process, and the volatile solvent must not be vaporized, and the pressure must be kept above the vapor pressure of the solvent after preheating.

[0034] The second step is secondary jet flash drying;

[0035] The preheated monomer is transported to the jet flash dryer 7 through the back pressure valve 6, and is first sprayed into the spray pipe in the first injector 73 through the small hole of the first distribution plate 72. The flow rate and pressure drop sharply, the volatile solvent partially evaporates, absorbs heat, and the material temperature drops. The spray steam enters the spray pipe through the air inlet hole and mixes with the material, and provides heat for the material. The diameter of the spray pipe in the first injector should not be too large. On the one hand, the first flash evaporation should not be controlled too fast, and the heat supply cannot be satisfied. In addition, if the pipe diameter is too large, the mixed heating effect of the material and steam is poor.

[0036] After the first flash evaporation, the material is partially vaporized, and the complete flash evaporation needs to continue to replenish energy. Therefore, after the first flash evaporation, the material is sprayed into the spray pipe in the second injector 75 through the small holes on the second distribution plate 74, and the pressure in the spray pipe continues to drop to a negative pressure state, the volatile solvent continues to evaporate, and the temperature will further drop. The high-pressure steam enters the spray pipe and further mixes and heats the material, and the gas-solid separated material is transported to the gas-solid separation tank 79 in time for separation. If the material is not heated by the spray steam, it is very easy to cause problems such as too low material temperature and poor fluidity. At the same time, because the gas and solid cannot form a good vulcanization state, the separated material cannot be removed in time, which can easily cause pipeline blockage.

[0037] Example 3

[0038] A solvent removal system as described in Example 2 was used.

[0039] MESA acid ester, liquid alkali and methanol generate 65% 16-18 fatty acid methyl ester sulfonate in neutralization system 1, the temperature is about 50℃, and the materials at 130℃ are transported and circulated by feed pump 2 and then mixed and enter preheater 3 for heating. After heating, the temperature is 130℃ and the back pressure is 0.9MPa. The circulation ratio is 5:1, that is, the flow rate in the preheater increases by 5 times.

[0040] The preheated monomer material is transported to the jet flash dryer 7, and the pressure at the feed port drops to 0.4MPa. Then it enters the injection pipe in the first injector 73 through the small holes on the upper head and the first distribution plate 72, and the temperature will drop. The temperature is maintained above 110°C and the pressure is maintained at 0.2MPa by supplementing the injection pipe steam. Then it is transported to the injection pipe in the second injector 75 through the small holes on the second distribution plate 74, and the outlet temperature is maintained above 105°C and the pressure is maintained at -0.085MPa. After leaving the injection pipe, the gas-solid two phases are separated in the gas-solid separation tank 79. The gas at 105°C is condensed and removed by a vacuum pump, and the molten MES is transported to the next process through the discharge extruder 8. The degree of drying is controlled by the flow rate of 16-18 fatty acid methyl ester sulfonate.

Claims

1. A jet flash dryer, Features: The invention comprises an injection cylinder, wherein an upper end cap (71) is fixed at the upper end of the injection cylinder, and a feed port (70) is provided on the upper end cap (71); a first distribution plate (72), a first injector (73), a second distribution plate (74) and a second injector (75) are provided inside the injection cylinder; the upper end cap (71) and the first injector (73) are connected by a flange, and the first distribution plate (72) is sandwiched between the two; the first injector (73) and the second injector (75) are connected by a flange, and the second distribution plate (74) is sandwiched between the two; small holes are provided on the first distribution plate and the second distribution plate respectively; injection pipes are provided in the first injector and the second injector respectively, and air inlet holes are provided on the injection pipes; the lower end of the injection cylinder is connected to a gas-solid separation tank (79) by a flange; and an air inlet port 1 (76) and an air inlet port 2 (77) are provided on the side surface of the upper end of the injection cylinder.

2. The jet flash dryer according to claim 1, Features: The diameter of the injection pipe and the diameter of the air inlet hole inside the second injector (75) are respectively larger than the diameter of the injection pipe and the diameter of the air inlet hole inside the first injector (73).

3. The jet flash dryer according to claim 1, Features: The outlet at the upper portion of the gas-solid separation tank (79) is connected to a gas extraction system (9).

4. A surfactant solvent removal system comprising the jet flash dryer according to any one of claims 1 to 3, Features: It also includes a neutralization system (1), a feed pump (2), a preheater (3), a heat circulation pump (4) and a discharge extruder (8); the discharge port of the neutralization system (1) is connected to the lower feed port of the preheater (3) through the feed pump (2); the upper discharge port of the preheater is divided into two paths, one of which is connected to the lower feed port of the preheater (3) through the heat circulation pump (4), and a check valve (5) is provided on the pipeline; the other of which is connected to the feed port (70) of the jet flash dryer (7), and a back pressure valve (6) is provided on the pipeline; the lower end of the jet flash dryer (7) is connected to the discharge extruder (8).

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