• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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  • 优先权
    • 专利摘要:
    method for continuous preparation of high bulk density methiony crystal. The present invention relates to a method for the continuous preparation of high bulk density methionine crystals. the process of the method is as follows: a hydrolyzate, which is obtained from a reaction of 5-(ß-methylthioethyl)hydantoin and a potassium carbonate solution, is mixed with an externally circulating material from a dtb neutralization crystallizer with a gas phase neutralization section; after the mixture is cooled, the mixture enters a liquid distributor from a neutralizing region at the top of the crystallizer; the mixture is sprayed into droplets or liquid droplets in carbon dioxide gas for the neutralization reaction and then naturally falls into a crystallization region at the bottom to be mixed with a material in the region; the mixture grows into small crystals in a system to form crystals with larger particle diameters and meanwhile new crystal nuclei are formed; in a settling region in the middle part of the crystallization region, crystals with larger particle diameters sink in an elutriation collector, while small crystals circulate with the externally circulating material, and a part of the externally circulating material is used to elutriation of the crystals in the elutriation collector, and another part of this is used to mix with the hydrolyzate; and the crystals in the elutriation collector are separated, washed and dried to obtain high bulk density methionine product.
    公开号:BR112017017246B1
    申请号:R112017017246-1
    申请日:2015-12-23
    公开日:2021-06-01
    发明作者:Zhirong Chen；Zhixuan Wang；Cong Chen；Zhengjiang Wang；Cunchao Wang；Yin Li；Zhixiang ZHANG
    申请人:Shandong Nhu Amino Acid Co.,Ltd.；Zhejiang University；Zhejiang Nhu Co.,Ltd；
    IPC主号:
    专利说明:

    TECHNICAL FIELD
    [0001] The present disclosure belongs to the technical field of chemical processing. Specifically, the present disclosure is concerned with a method for the continuous preparation of high bulk density methionine crystals, and principally, it is concerned with a new method for crystallizing methionine and an improved crystallization device. RELATED TECHNIQUE
    [0002] Methionine is one of the essential amino acids for animal growth and is currently the only sulfur containing amino acid. It is an important food additive. Methionine products come in two forms: solid and liquid. Currently, solid methionine is dominant in the world methionine market.
    [0003] Currently, methionine is mainly synthesized by chemical methods. Depending on the raw material, the methods mainly include malonate method, acrolein method, and amino lactone method and so on. Major methionine manufacturers, such as Adisseo, Soda, Sumimoto and Degussa, adopt the method with acrolein. The method uses acrolein and methyl mercaptan as raw materials to produce methylthiopropanal and additionally performs condensation, hydrolysis and acidification crystallization to produce methionine. However, different manufacturers have different ways of hydrolysis and acidification crystallization. Adisseo uses NaOH for hydrolysis to produce sodium methionine and performs sulfuric acid crystallization to obtain methionine and a sodium sulfate by-product. Soda uses calcium hydroxide for hydrolysis and performs acidification with hydrochloric acid to obtain methionine and by-products of sodium chloride and calcium carbonate. The crystals produced by the acidification hydrolysis and crystallization methods are in powder form due to by-products and impurities. Such crystals cannot be easily separated and will easily generate dust during the drying and packaging process and in use.
    [0004] On the contrary, the acidification hydrolysis and crystallization method adopted by Degussa is more advantageous. The process uses hydrocyanic acid and methylthiopropanal for condensation to produce methylthio ethyl hydantoin and then uses potassium carbonate for hydrolysis and carbon dioxide for acidification crystallization to obtain methionine, and carbon dioxide and potassium bicarbonate as by-products can be recycled. Thus, the amount of solid waste is significantly reduced, making the method a clean production.
    [0005] In the process of preparing methionine using the above methods, the acidification crystallization process has been the focus of the study. Due to the use of carbon dioxide gas in the acidification process, methionine suspension has severe foaming, resulting in excess crystal core and very fine crystals in the crystallization process. In general, crystals are scaly crystals that are extremely fragile. Therefore, the solid-liquid separation is very bad. Severe foaming often interrupts the production process, making production not run normally.
    [0006] Currently, there are several studies that use improved equipment, improved processes or the addition of specific auxiliary substances to prevent foaming.
    [0007] Patent Document 1, as an initial patent, discloses a methionine crystallization process. The process is a hydrolysis process in which 5-(β-methylmercaptoethyl)hydantoin is hydrolyzed in the presence of potassium carbonate, followed by neutralization and crystallization by introducing carbon dioxide into the hydrolyzed solution and separating the precipitated methionine, and the Concentrated filtrate can be applied for the hydrolysis of 5-(β-methylmercaptoethyl)hydantoin. However, the neutralization and crystallization under the condition described by the above patent document has a severe foaming phenomenon. As a result, the finally obtained methionine crystal is flaky and has a low bulk density. If the shape of the methionine crystal is to be improved by recrystallization, additional equipment and energy are required, which are not economical.
    [0008] In order to solve the problem of foaming resulting from neutralization with carbon dioxide gas, Patent Document 2 uses the method of adding defoamer into the aqueous solution of alkali metal salts of methionine until the concentration of defoamer is 1000-10000 ppm. Thus, the obtained methionine crystals are spherical porous crystals with the particle diameters within the range of 100-200 µm. There are sticky substances and mother liquor residues in the micropores. In order to obtain a product that meets market quality requirements, a large amount of water is needed for washing, which increases energy consumption and reduces process economy.
    [0009] Patent Document 3 also uses additives (glutenin, polyvinyl alcohol, methylcellulose and the like) to control foaming. He points out that a portion of methionine dissolved in the mother liquor during the hydrolysis process forms a methionine polymer that affects the crystalline form of crystals precipitated during crystallization and recrystallization. The methionine polymer is decomposed by heating the hydrolyzed solution at 160 to 200 °C for 1 to 5 hours in order to control the amount of polymer. In the methionine crystal method described above, the resulting crystals are in the form of granules or thick plates with a bulk density of 625 kg/m3. In this document, although the methionine polymer is hydrolyzed by heating the hydrolyzed solution, the apparent density of the crystal particles obtained is still not high. Furthermore, heating the hydrolyzed solution for a long time increases energy consumption and reduces the production capacity of the production plant.
    [00010] Patent Document 4 proposes the use of a crystallization vessel with a suction tube to obtain methionine crystals by semi-gradual crystallization. The process includes neutralizing and crystallizing 15 to 40% of the aqueous methionine solution along with a coagulant (sorbitan laurate, polyvinyl alcohol or hydroxypropyl methyl cellulose) in batches for 20 to 40 minutes to make the seed crystals grow, then adding the remaining 60 to 85% of the aqueous methionine solution for continuous neutralization and crystallization for 40-90 minutes to make the crystals grow. The bulk density of the methionine crystal obtained under the conditions described in this document is 550 kg/m3, which is still not high.
    [00011] In Patent Document 5, it is proposed that the amount of by-product methionine polymer in the hydrolyzed solution can be reduced by hydrolysis without stirring in the first reactor and by heating in the second reactor; polyvinyl alcohol is used as the flocculant while the mother liquor for the primary crystallization is applied to the hydrolyzed solution to recycle, thereby obtaining a methionine crystal with a high bulk density. The apparent density of the obtained methionine crystals is 703 kg/m3 at the crystallization temperature of 10 to 30°C and under carbon dioxide pressure of 0.1 to 1 MPa. In this process, by heating the hydrolyzed solution twice, the bulk density of the crystals increases by merely 5% compared to comparative examples, but the necessary equipment and energy consumption increase.
    [00012] Patent Document 6 uses a vacuum crystallization method to recrystallize a crude methionine to increase the apparent density of the crystal. The process includes dissolving the crude methionine with a solvent and an additive at 100 °C, feeding the dissolved matters into a vacuum crystallizer, controlling the crystallizer temperature by means of a degree of vacuum, the temperature for the first crystallization being controlled at 60-70 °C and the temperature for the second crystallization being controlled at 30-50 °C. The methionine crystals finally obtained have a bulk density of 640 kg/m3. However, in the recrystallization step, the crude methionine needs to be reheated to dissolve and cooled, followed by a large amount of liquid circulation which increases energy consumption and reduces process economy.
    [00013] In addition, many other patents use additives to eliminate the phenomenon of foaming during the crystallization of methionine. JP10306071 provides a method for defoaming, in which methionine is crystallized when the potassium salt solution of methionine is neutralized with an acid in the coexistence of glutenin. JPS43-22285 uses a crystallization method in which the methionine salt solution is neutralized and crystallized in the coexistence of soluble cellulose derivatives so as to eliminate foam. JPS43-24890 uses a method in which the methionine salt solution is neutralized and crystallized in the coexistence of alcohols, phenols and ketones in order to eliminate foam. JPS46-19610 uses a method in which the methionine salt solution is neutralized and crystallized into a solution, added with anionic and nonionic surfactants, in order to eliminate foam. JP2921097 discloses a method in which a methionine potassium salt solution is neutralized and crystallized in the coexistence of polyvinyl alcohol by absorbing carbon dioxide gas in order to eliminate the foam.
    [00014] As shown above, when the methionine salt solution is neutralized and crystallized with carbon dioxide, the foaming phenomenon is a significant factor affecting the neutralization and crystallization results during the crystallization process. In order to avoid or reduce the foaming phenomenon, so as to obtain ideal crystals, most prior art add defoamers, flocculants and other additives during the crystallization process. A part of these additives will be bonded to the surface of the crystals and will be presented by the methionine products, while the rest remains in the mother liquor to be recycled along with the mother liquor. Recycling of the additives backside will change in proportion to the additives in the mother liquor or deteriorate to unknown material due to heat, thereby affecting the neutralization and further crystallization process and increasing the instability in the neutralization and crystallization process. Furthermore, high bulk density methionine crystal products cannot be obtained merely by adding additives. Some patent documents describe the use of recrystallization steps to enhance the bulk density of methionine crystals. But the recrystallization process requires additional equipment and energy consumption, which reduces the economics of the production process.
    [00015] Prior art documents: Patent Document 1: JPS54-9174 Patent Document 2: DE19547236 Patent Document 3: CN1589259 Patent Document 4: CN1274717 Patent Document 5: CN101602701 Patent Document 6: WO2013139562 SUMMARY Problem a be solved
    [00016] The present disclosure intends to solve the following technical problem existing in several methods of production of methionine crystal in the state of the art: foams are easily generated, the bulk density is not high and the use of additives affects the crystallization process. When using a DTB neutralization crystallizer with a gas-phase neutralization section, the neutralization in the liquid phase that is easy to generate a foaming phenomenon is transferred to be carried out in a gas-phase, so as to essentially eliminate the problem of foaming in the neutralization process. However, by controlling the supersaturation in the crystallization process, crystal core formation is effectively controlled, thereby obtaining high bulk density methionine products. Solution to solve the problem
    [00017] One of the technical solutions of the present disclosure is about a method for the continuous preparation of high bulk density methionine crystals, the method comprising the following steps: (1) mixing a hydrolyzed solution containing potassium methionine obtained from a reacting 5-(β-methylmercaptoethyl)hydantoin and a potassium carbonate solution with an externally circulating material from a DTB neutralization crystallizer with a gas phase neutralization section to form a mixed material; the mixing material that enters a liquid distributor from a neutralizing region in an upper part of the crystallizer after being cooled and sprayed in the form of liquid droplets or drops to the gas-liquid contact area to carry out a reaction of neutralization with carbon dioxide gas to obtain a neutralizing solution containing methionine; (2) making the neutralizing solution naturally fall into a crystallization region at the bottom of the crystallizer to form crystals in the crystallization region and then causing the crystals to deposit larger particle diameters in an elutriation collector in a deposit area in the middle part of the crystallization region; (3) feed the methionine crystals into the elutriation manifold via a crystal slurry pump inside a rotating cylinder filter to be subjected to separation, washing and drying to obtain methionine products; wherein the externally circulating material is initially a saturated methionine solution.
    [00018] The bulk density of high bulk density methionine crystals is at least 800 kg/m3.
    [00019] Preferably, a hydrolyzed solution containing potassium methionine obtained by a reaction of 5-(β-methylmercaptoethyl)hydantoin with a potassium carbonate solution is pre-cooled and then mixed with an externally circulating material of the same temperature as the neutralizing crystallizer to form a mixed material.
    [00020] In addition, preferably, the formation of crystals includes the following step: the neutralizing solution enters the crystallization region and is stirred in the crystallizer to be mixed with the material in the crystallization region, and fine crystals formed in the system grow to form crystals with a larger particle diameter; however, once the methionine solution is in a supersaturated state, a new crystal core can be formed.
    [00021] In addition, preferably, in the deposit area of the crystallization region, fine crystals and a part of the methionine solution enter into the external circulation tube to be cooled and circulated; a part of the externally circulating material is used to wash the crystals in the elutriation collector, while another part of these is used to be mixed with the hydrolyzed solution containing potassium methionine.
    [00022] In addition, preferably, the DTB neutralization crystallizer with a gas-phase neutralization section has a gas-phase space in an upper part, and a liquid distributor and a gas distributor are provided so that the liquid as a dispersed phase is subjected to a gas-liquid neutralization reaction into a carbon dioxide gas as a continuous phase.
    [00023] The volume ratio of the reaction solution (hydrolyzed solution) containing potassium methionine that enters the external circulation tube of the DTB neutralization crystallizer with a gas phase neutralization section in relation to the external circulation solution is 1:5 -50, preferably 1:10-30, and the temperature of the mixed material is reduced by a cooler at 0.5-5 °C, preferably at 1-3 °C and is stabilized at 20-40 °C after the cycle of cooling.
    [00024] The volume ratio of the externally circulating solution entering the elutriation collector of the DTB neutralization crystallizer with a gas phase neutralization section in relation to the exit volume of the crystal pulp is 1-5:1 and preferably 1.5-4:1.
    [00025] The agitation rate in the crystallization region of the DTB neutralization crystallizer with a gas phase neutralization section is 50-500 rpm, preferably 100-300 rpm.
    [00026] The temperature of the crystallization region of the DTB neutralization crystallizer with a gas-phase neutralization section is from 10 to 40 °C, preferably from 20 to 30 °C.
    [00027] The hydrolyzed solution containing potassium methionine is in the DTB neutralization crystallizer with a gas phase neutralization section 0.3-3 hours, preferably 0.5-2 hours. The flow rate of the hydrolyzed solution containing potassium methionine entering the neutralizing crystallizer is from 0.333 to 3.33 m3/h and preferably from 0.5 to 2 m3/h.
    [00028] The gas phase carbon dioxide pressure in the DTB neutralization crystallizer with a gas phase neutralization section is from 0.3 to 1.2 Mpa and preferably from 0.4 to 1.0 Mpa.
    [00029] The present disclosure further provides a DTB neutralization crystallizer with a gas phase neutralization section for the continuous preparation of high bulk density methionine crystals, comprising: (4) a liquid distributor for forming droplets or drops of mixed distillate liquid containing potassium methionine and a gas distributor for supplying carbon dioxide gas which are provided in a neutralizing region in an upper part, (5) a liquid guiding cover and an agitator provided in the middle part , (6) a crystal deposit area provided in a lower part, which includes an elutriation collector for depositing crystals, (7) an external circulation system, to be partially supplied to the elutriation collector and to be partially mixed with the hydrolyzed solution containing potassium methionine and then circulate the supply to the orientation cover with the baffle at the material inlet of the body. Neutralizing crystallizer.
    [00030] Furthermore, the DTB neutralization crystallizer with a gas-phase neutralization section additionally comprises a rotating cylinder filter for separating and washing the crystal pulp from the elutriation collector.
    [00031] The present application is characterized by: easily transferring the foaming neutralization reaction of the hydrolyzed solution containing potassium methionine and carbon dioxide from the liquid phase to the gaseous phase, the problem of ease of foaming in the neutralization in the liquid phase is fundamentally resolved. However, the supersaturation of methionine in the neutralization solution can be effectively controlled by mixing and diluting the hydrolyzed solution containing potassium methionine and the externally circulating solution and then neutralized with gas-phase carbon dioxide, thereby controlling the amount of new methionine crystal core generated and enabling the methionine crystals to grow to obtain high bulk density methionine crystal products with larger particle diameters. Disclosure effect
    [00032] The present disclosure has the following advantages: the present disclosure uses a reaction solution containing potassium methionine to perform continuous neutralization crystallization in the DTB neutralization crystallizer with a gas phase neutralization section. The production process has good stability and high efficiency. The obtained products have stable quality. Therefore, the present disclosure is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS
    [00033] Fig. 1 is an illustration of an embodiment of the DTB neutralization crystallizer with a gas phase neutralization section according to the present disclosure. Reference signs 1 liquid distributor 2 gas distributor 3 orientation cover 4 agitator arm 5 rotating cylinder filter 6 crystal slurry pump 7 external circulation pump 8 , 9 flowmeter 10 cooling heat exchanger 11 circulation outlet external 12 external circulation outlet 13 CO2 gas inlet 14 mother liquor 15 crystal 16 hydrolyzed solution 17 boiling surface 18 cylindrical baffle 19 elutriation collector A gas-liquid contact neutralization region B clarification region C deposit area crystal D large crystal concentration region
    [00034] The present disclosure is specifically described with reference to non-limiting embodiments as follows. DETAILED DESCRIPTION Example 1
    [00035] The DTB neutralization crystallizer with a gas phase neutralization section of the present disclosure has the following configuration including a liquid phase section with a volume of 1 m3 which is designed according to the conventional DTB structure ratio; a gas phase section with a volume of 0.6 m3 in a shape of a cylindrical body with an elliptical sealed head, whose diameter is 600 mm and the height is 2200 mm; a liquid distributor provided at the top; and a carbon dioxide gas distributor provided at the bottom.
    [00036] In the DTB neutralization crystallizer with a gas phase neutralization section of the present disclosure, 0.9 m3 of saturated solution of methionine is added in advance, followed by 10 kg of seed crystal of methionine ground to have a diameter of no. more than 10 micrometers. Then, the crystallizer starts to stir at 100 rpm. Turn on the external circulation pump and adjust the flow rate of the external circulating solution entering the elutriation collector to 1.6 m3/h and the flow rate of the external circulating solution to be mixed with the hydrolyzed solution containing potassium methionine to 10 m3/h. After the circulation flow is stable, start the circulation cooling to maintain the temperature at 28°C. Carbon dioxide is introduced from the gas distributor until the pressure is up to 0.8 Mpa. At this point, a hydrolyzed solution containing 19% potassium methionine at 28 °C is introduced at a flow rate of 1 m3/h (ie 1 hour retention time). After mixing with externally circulating material, the mixture is cooled by a cooler to 25°C and enters the liquid distributor at the top of the crystallizer. The liquid is sprayed as a droplet onto carbon dioxide gas for the neutralization reaction to become a neutralizing solution and fall onto the liquid surface of the crystallizer. The temperature of the neutralizing solution which fell on the liquid surface of the crystallizer increased to 28°C. After mixing with stirring, seed crystals in the crystallizer grow. At the same time, a certain amount of new seed crystals will be produced due to supersaturation.
    [00037] After the hydrolyzed solution containing potassium methionine has been introduced for 6 minutes, the crystal slurry pump is turned on to feed methionine crystal slurry into the rotating cylinder filter at a flow rate of 1.1 m3/h for filtering and washing. Methionine products will be obtained after continuous fluidizing desiccation of the filter sludge. After the operation has become fully stable (taking about 4 hours), methionine crystal products can be obtained at a yield of 112 kg/h, whose density is 811 kg/m3.
    [00038] The phenomenon of foaming is not observed during the entire process of continuous operation for 24 hours. Example 2
    [00039] In the DTB neutralization crystallizer with a gas phase neutralization section of Example 1, 0.9 m3 of saturated solution of methionine is added in advance, followed by 10 kg of seed crystal of methionine ground to have a diameter of no. more than 10 micrometers. Then, the crystallizer starts to stir at 200 rpm. Turn on the external circulation pump and adjust the flow rate of the external circulating solution entering the elutriation collector to 1.5 m3/h and the flow rate of the external circulating solution to be mixed with the hydrolyzed solution containing potassium methionine to 20 m3/h. After the circulation flow is stable, start the circulation cooling to keep the temperature at 20 °C. Carbon dioxide is introduced from the gas distributor until the pressure is up to 0.4 Mpa. At this point, a hydrolyzed solution containing 19% potassium methionine at 20 °C is introduced at a flow rate of 0.5 m3/h (ie retention time of 2 hours). After mixing with externally circulating material, the mixture is cooled by a cooler to 18°C and enters the liquid distributor at the top of the crystallizer. The liquid is sprayed as a droplet onto carbon dioxide gas for the neutralization reaction to become a neutralizing solution and fall onto the liquid surface of the crystallizer. The temperature of the neutralizing solution which fell on the liquid surface of the crystallizer increased to 20°C. After mixing with stirring, seed crystals in the crystallizer grow. At the same time, a certain amount of new seed crystals will be produced due to supersaturation.
    [00040] After the hydrolyzed solution containing potassium methionine has been introduced for 12 minutes, the crystal slurry pump is turned on to feed methionine crystal slurry into the rotating cylinder filter at a flow rate of 0.55 m3/h for filtering and washing. Methionine products will be obtained after continuous fluidizing desiccation of the filter sludge. After the operation has become fully stable (taking about 8 hours), methionine crystal products can be obtained at a yield of 57 kg/h, whose density is 816 kg/m3.
    [00041] The foaming phenomenon is not observed during the entire 24-hour continuous operation process. Example 3
    [00042] In the DTB neutralization crystallizer with a gas phase neutralization section of Example 1, 0.9 m3 of saturated solution of methionine is added in advance, followed by 10 kg of seed crystal of methionine ground to have a diameter of no. more than 10 micrometers. Then, the crystallizer starts shaking at 400 rpm. Turn on the external circulation pump and adjust the flow rate of the external circulating solution entering the elutriation collector to 4 m3/h and the flow rate of the external circulating solution to be mixed with the hydrolyzed solution containing potassium methionine to 10 m3 /H. After the circulation flow is stable, start the circulation cooling to maintain the temperature at 35 °C. Carbon dioxide is introduced from the gas distributor until the pressure is up to 1.0 Mpa. At this point, a hydrolyzed solution containing 19% potassium methionine at 35 °C is introduced at a flow rate of 2 m3/h (ie, retention time of 0.5 hour). After mixing with externally circulating material, the mixture is cooled by a cooler to 30 °C and enters the liquid distributor at the top of the crystallizer. The liquid is sprayed as a droplet onto carbon dioxide gas for the neutralization reaction to become a neutralizing solution and fall onto the liquid surface of the crystallizer. The temperature of the neutralizing solution which fell on the liquid surface of the crystallizer increased to 35 °C. After mixing with stirring, seed crystals in the crystallizer grow. At the same time, a certain amount of new seed crystals will be produced due to supersaturation.
    [00043] After the hydrolyzed solution containing potassium methionine has been introduced for 3 minutes, the crystal slurry pump is turned on to feed methionine crystal slurry into the rotating cylinder filter at a flow rate of 2.2 m3/h for filtering and washing. Methionine products will be obtained after continuous fluidizing desiccation of the filter sludge. After the operation has become fully stable (taking about 2 hours), methionine crystal products can be obtained at a yield of 221 kg/h, whose density is 802 kg/m3.
    [00044] The phenomenon of foaming is not observed during the entire 24-hour continuous operation process. Example 4
    [00045] In the DTB neutralization crystallizer with a gas-phase neutralization section of Example 1, 0.9 m3 of saturated solution of methionine is added in advance, followed by 10 kg of seed crystal of methionine ground to have a diameter of no. more than 10 micrometers. Then, the crystallizer starts to stir at 50 rpm. Turn on the external circulation pump and adjust the flow rate of the external circulation solution entering the elutriation collector to 1.83 m3/h and the flow rate of the external circulation solution to be mixed with the hydrolyzed solution containing potassium methionine to 16.66 m3/h. After the circulation flow is stable, start the circulation cooling to maintain the temperature at 40 °C. Carbon dioxide is introduced from the gas distributor until the pressure is up to 1.2 Mpa. At this point, a hydrolyzed solution containing 19% potassium methionine at 40 °C is introduced at a flow rate of 0.333 m3/h (ie, retention time of 3 hours). After mixing with externally circulating material, the mixture is cooled by a cooler to 39.5 °C and enters the liquid distributor at the top of the crystallizer. The liquid is sprayed as a droplet onto carbon dioxide gas for the neutralization reaction to become a neutralizing solution and fall onto the liquid surface of the crystallizer. The temperature of the neutralizing solution that fell on the liquid surface of the crystallizer increased to 40°C. After mixing with stirring, seed crystals in the crystallizer grow. At the same time, a certain amount of new seed crystals will be produced due to supersaturation.
    [00046] After the hydrolyzed solution containing potassium methionine has been introduced for 18 minutes, the crystal slurry pump is turned on to feed methionine crystal slurry into the rotating cylinder filter at a flow rate of 0.366 m3/h for filtration and washing. Methionine products will be obtained after continuous fluidizing desiccation of the filter sludge. After the operation has become fully stable (taking about 12 hours), methionine crystal products can be obtained at a yield of 36 kg/h, whose density is 822 kg/m3.
    [00047] The phenomenon of foaming is not observed during the entire 24-hour continuous operation process. Example 5
    [00048] In the DTB neutralization crystallizer with a gas phase neutralization section of Example 1, 0.9 m3 of saturated solution of methionine is added in advance, followed by 10 kg of seed crystal of methionine ground to have a diameter of no. more than 10 micrometers. Then, the crystallizer starts shaking at 500 rpm. Turn on the external circulation pump and adjust the flow rate of the external circulation solution entering the elutriation collector to 3.67 m3/h and the flow rate of the external circulation solution to be mixed with the hydrolyzed solution containing potassium methionine to 16.66 m3/h. After the circulation flow is stable, start the circulation cooling to maintain the temperature at 10 °C. Carbon dioxide is introduced from the gas distributor until the pressure is up to 0.3 Mpa. At this point, a hydrolyzed solution containing 15% potassium methionine at 10 °C is introduced at a flow rate of 3.33 m3/h (ie retention time of 0.3 hours). After mixing with externally circulating material, the mixture is cooled by a cooler to 5 °C and enters the liquid distributor at the top of the crystallizer. The liquid is sprayed as a droplet onto carbon dioxide gas for the neutralization reaction to become a neutralizing solution and fall onto the liquid surface of the crystallizer. The temperature of the neutralizing solution which fell on the liquid surface of the crystallizer increased to 10°C. After mixing with stirring, seed crystals in the crystallizer grow. At the same time, a certain amount of new seed crystals will be produced due to supersaturation.
    [00049] After the hydrolyzed solution containing potassium methionine has been introduced for 1.8 minutes, the crystal slurry pump is turned on to feed methionine crystal slurry into the rotating cylinder filter at a flow rate of 3.67 m3 /h for filtering and washing. Methionine products will be obtained after continuous fluidizing desiccation of the filter sludge. After the operation has become fully stable (taking about 1.2 hours), methionine crystal products can be obtained at a yield of 268 kg/h, whose density is 805 kg/m3.
    [00050] The foaming phenomenon is not observed during the entire 24-hour continuous operation process. Comparative Example
    [00051] The experiment is carried out in the same way as in Example 1, except that gaseous carbon dioxide is introduced into the crystallizer from the liquid phase.
    [00052] In the DTB neutralization crystallizer with a gas-phase neutralization section of Example 1, 0.9 m3 of saturated solution of methionine is added in advance, followed by 10 kg of seed of methionine ground to have a diameter of no more than 10 micrometers. Then, the crystallizer starts to stir at 100 rpm. Turn on the external circulation pump and adjust the flow rate of the external circulating solution entering the elutriation collector to 1.1 m3/h and the flow rate of the external circulating solution to be mixed with the hydrolyzed solution containing potassium methionine to 10 m3/h. After the circulation flow is stable, start the circulation cooling to maintain the temperature at 28°C. Carbon dioxide is introduced from the gas distributor until the pressure is up to 0.5 Mpa. At this point, a hydrolyzed solution containing 19% potassium methionine at 28 °C is introduced at a flow rate of 1 m3/h (ie 1 hour retention time). After mixing with externally circulating material, the mixture is cooled by a cooler to 25°C and enters the liquid distributor at the top of the crystallizer. The liquid falls in drop form on the liquid surface of the crystallizer. After mixing with agitation, the liquid neutralizes with carbon dioxide dissolved in a liquid phase so that the seed crystals in the crystallizer grow. At the same time, a certain amount of new seed crystals will be produced due to supersaturation.
    [00053] After the hydrolyzed solution containing potassium methionine has been introduced for 6 minutes, the crystal slurry pump is turned on to feed methionine crystal slurry into the rotating cylinder filter at a flow rate of 1.1 m3/h for filtering and washing. Methionine products will be obtained after continuous fluidizing desiccation of the filter sludge. After the operation has become fully stable (taking about 4 hours), methionine crystal products can be obtained at a yield of 111 kg/h, whose density is 518 kg/m3.
    [00054] During continuous 24-hour operation, the phenomenon of foaming occurs throughout the process. Defoamer needs to be added continuously to keep the neutralization and crystallization process going. Table 1

    [00055] Referring to Table 1, in the production method of Comparative Example 1, the conditions for operation are substantially the same with the method of the present application. Comparative Example 1 differs from the present application merely by introducing carbon dioxide into the liquid phase, which results in the evident foaming phenomenon. Thus, the methionine crystal product obtained by Comparative Example 1 is affected; and the bulk density cannot meet the requirement of this application. Industrial Applicability
    [00056] By neutralization and continuous crystallization using a reaction solution containing potassium methionine in a DTB neutralization crystallizer with a gas phase neutralization section, the present disclosure transfers the neutralization reaction from the hydrolyzed solution containing potassium methionine and carbon dioxide. carbon, which is easy to generate a foaming phenomenon from the liquid phase to the gas phase. Thus, the production process achieves good stability and high efficiency. The obtained products have a stable quality. Therefore, the method of the present disclosure is suitable for industrial production.
    权利要求:
    Claims (9)
    [0001]
    1. Method for the continuous preparation of high bulk density methionine crystals, characterized in that it comprises the following steps: (1) mixing a hydrolyzed solution containing potassium methionine obtained from a reaction of 5-(β-methylmercaptoethyl ) hydantoin and a potassium carbonate solution with an externally circulating material from a neutralizing crystallizer (DTB) with a gas-phase neutralization section to form a blended material; the mixing material, which enters a liquid distributor (1) from a neutralizing region (A) in an upper part of the crystallizer after being cooled and sprayed in the form of liquid droplets or drops to the contact area of gas-liquid carry out a neutralization reaction with carbon dioxide gas, so as to obtain a neutralizing solution containing methionine; (2) make the neutralizing solution fall naturally into a crystallization region at the bottom of the crystallizer to form crystals in the crystallization region and then cause the crystals to deposit larger particle diameters in an elutriation collector (19 ) in a deposit area in the middle part of the crystallization region; (3) feed the methionine crystals in the elutriation collector (19) through a crystal slurry pump (6) into a rotating cylinder filter (5) to be subjected to separation, washing and drying to obtain products of methionine; wherein the externally circulating material is initially a saturated methionine solution; wherein the DTB neutralization crystallizer with a gas-phase neutralization section has a gas-phase space in an upper part, and a liquid distributor (1) and a gas distributor (2) are provided so that the liquid as a dispersed phase is subjected to a gas-liquid neutralization reaction into a carbon dioxide gas as a continuous phase; and wherein the bulk density of the high bulk density methionine crystals is at least 800kg/m3.
    [0002]
    2. Method for the continuous preparation of high bulk density methionine crystals, according to claim 1, characterized in that the crystallization process comprises cultivating fine crystals already formed in the crystallization region to form crystals with larger particle diameters , by controlling supersaturation to form new crystal nuclei.
    [0003]
    3. Method for the continuous preparation of high bulk density methionine crystals, according to claim 1, characterized in that in the deposit area in the middle part of the crystallization region, fine crystals and a part of the methionine solution enter in an external circulation tube (11) for cooling and circulation; and a part of the externally circulating materials is used for elutriation of the crystals in the elutriation collector (19), while another part of these is used to be mixed with the hydrolyzed solution (16) containing potassium methionine.
    [0004]
    4. Method for the continuous preparation of high bulk density methionine crystals according to claim 1 or 2, characterized in that a proportion by volume of the hydrolyzed solution containing potassium methionine in the external circulation tube of the neutralization crystallizer DTB with a gas phase neutralization section in relation to externally circulating material is 1:5-50, and the temperature of the material after being mixed is reduced by a cooler by 0.5 to 5 °C.
    [0005]
    5. Method for the preparation of high bulk density methionine crystals according to claim 1 or 2, characterized in that the volume ratio of the material circulating externally in the elutriation collector (19) in the lower part of the crystallizer of DTB neutralization with a gas phase neutralization section to crystal pulp output volume is (1-5:1):1.
    [0006]
    6. Method for the continuous preparation of high bulk density methionine crystals according to claim 1 or 2, characterized in that the agitation rate in the crystallization region of the DTB neutralization crystallizer with a phase neutralization section gas is from 50 to 500 rpm.
    [0007]
    7. Method for the continuous preparation of high bulk density methionine crystals according to claim 1 or 2, characterized in that the temperature of the crystallization region of the DTB neutralization crystallizer with a gas phase neutralization section is from 10 to 40°C.
    [0008]
    8. Method for the continuous preparation of high bulk density methionine crystals, according to claim 1 or 2, characterized in that the hydrolyzed solution containing potassium methionine remains in the neutralization crystallizer for 0.3 to 3 hours.
    [0009]
    9. Method for the continuous preparation of high bulk density methionine crystals according to claim 1 or 2, characterized in that the gas phase carbon dioxide pressure in the DTB neutralization crystallizer with a neutralizing section of gas phase is 0.3 to 1.2 Mpa.
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    同族专利:
    公开号 | 公开日
    KR101975189B1|2019-05-07|
    JP6423109B2|2018-11-14|
    CN104744326B|2016-08-10|
    EP3246310A4|2018-01-10|
    JP2018504453A|2018-02-15|
    AU2015382630B2|2018-05-17|
    EP3246310B1|2019-08-07|
    RU2678585C2|2019-01-30|
    CA2974447A1|2016-08-18|
    SG11201705530VA|2017-08-30|
    EP3246310A1|2017-11-22|
    KR20170106400A|2017-09-20|
    WO2016127707A1|2016-08-18|
    BR112017017246A2|2018-04-17|
    CN104744326A|2015-07-01|
    AU2015382630A1|2017-08-24|
    US10293273B2|2019-05-21|
    RU2017121649A|2018-12-21|
    US20180043281A1|2018-02-15|
    RU2017121649A3|2018-12-21|
    ZA201705902B|2018-12-19|
    MX2017010418A|2018-06-07|
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    法律状态:
    2019-10-29| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2021-05-04| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-06-01| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 23/12/2015, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    CN201510078388.1A|CN104744326B|2015-02-12|2015-02-12|A kind of method preparing the crystallization of high-bulk-density methionine continuously|
    CN201510078388.1|2015-02-12|
    PCT/CN2015/098368|WO2016127707A1|2015-02-12|2015-12-23|Method for continuous preparation of high bulk density methionine crystal|
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