CN109438182B - Production system and production process of 99-grade pentaerythritol - Google Patents
Production system and production process of 99-grade pentaerythritol Download PDFInfo
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- CN109438182B CN109438182B CN201811622120.XA CN201811622120A CN109438182B CN 109438182 B CN109438182 B CN 109438182B CN 201811622120 A CN201811622120 A CN 201811622120A CN 109438182 B CN109438182 B CN 109438182B
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Abstract
The invention discloses a production system and a production process of 99-grade pentaerythritol, wherein the production system comprises a feeding unit, a reaction unit, an aldehyde removal unit, an alcohol removal unit, an evaporation unit, a crystallization unit, a centrifugal unit and a drying unit which are sequentially arranged; the invention adopts a sodium method to continuously produce pentaerythritol, wherein the pentaerythritol takes formaldehyde and acetaldehyde as raw materials to carry out condensation reaction under the catalysis of liquid alkali, formic acid is used for neutralization after the reaction is stopped, thereby pentaerythritol and byproduct sodium formate are generated, and then 99-grade pentaerythritol finished products are obtained through the working procedures of aldehyde removal, alcohol removal, evaporation, crystallization, separation, drying and the like. The invention can realize the co-production technology of mono-di-tripentaerythritol and reduce the generation of byproducts, thereby improving the purity and the yield, leading the formaldehyde removal rate to reach 99.9% by removing aldehyde and reducing the residual formaldehyde content in the product. The automatic production line has higher automation degree, less labor intensity and less personnel concentration, improves the production efficiency of pentaerythritol, and reduces the investment of production cost.
Description
Technical Field
The invention belongs to the technical field of pentaerythritol production processes, and particularly relates to a 99-grade pentaerythritol production system and a production process thereof.
Background
Pentaerythritol of formula C5H12O4White crystals or powder, is flammable, is easy to be esterified by common organic acid, and is widely used for producing alkyd resin, synthetic high-grade lubricant, plasticizer, surfactant in the coating industry and used as raw materials of medicines, explosives and the like. Pentaerythritol is used primarily in the paint industry and can be used to make alkyd paints with improved hardness, gloss and durability of the paint film. It is also used as raw material of rosin ester for colour paint, varnish and printing ink, etc. and can be used for preparing drying oil, negative-fire coating and aviation lubricating oil, etc. Fatty acid esters of pentaerythritol are highly effective lubricants and plasticizers for polyvinyl chloride, and epoxy derivatives thereof are the starting materials for the production of nonionic surfactants. Pentaerythritol is prone to forming complexes with metals, is also used as a hard water softener in detergent formulations, and is also used in the production of pharmaceuticals, pesticides, and the like. Pentaerythritol contains four equivalent hydroxymethyl groups in the molecule and has high symmetry, so that the pentaerythritol is often used as a raw material for preparing multifunctional compounds. The pentaerythritol tetranitrate can be prepared by nitration of the mixture, and is a strong explosive; esterification to obtain pentaerythritol triacrylate for paint. Furthermore, pentaerythritol can also be used as a flame retardant of the adhesive, and can be matched with ammonium polyphosphate to obtain an intumescent flame retardant; can also be used as a crosslinker for polyurethanes to provide branching within the polyurethane.
At present, the domestic production of pentaerythritol is mainly based on the principle of condensation reaction, sodium hydroxide is taken as a condensing agent, and the reaction formula is 4CH2O+CH3CHO+NaOH=C(CH2OH)4+ HCOONa produces dipentaerythritol, tripentaerythritol, polypentaerythritol, pentaerythritol cyclic formal, sodium formate and trace methanol, and the common process in the prior art has the disadvantages of great material ratio fluctuation, more byproducts and low pentaerythritol content in the feeding process of the condensation reaction. The continuous production method is adopted in foreign countries, the product quality is good, and the energy consumption is low. In China, except that a continuous production mode is adopted in cloudy weather, 98 grades can be directly produced, other enterprises are interstitial condensation processes, 98 grades are prepared by secondary purification, and the energy consumption is relatively high. In addition, in the application fields of surfactants, antioxidants, medicines, explosives and the like, the domestic pentaerythritol is still insufficient compared with foreign special products and cannot be replaced.
The patent application document with the application number of 201410501653.8 discloses a preparation method of 95-grade pentaerythritol, which mainly comprises the basic steps of condensation, preheating, dealdehyding separation, triple effect evaporation and the like, and also comprises the following steps: heating the mixed solution obtained by the triple-effect evaporator; cooling the mixed solution to 80-90 ℃, centrifuging, and drying to obtain 95-grade pentaerythritol; heating the mother liquor and cooling to obtain 92-grade pentaerythritol. The method for preparing 95-grade pentaerythritol provided in the patent application document has the characteristics of low investment, low energy consumption, simple method, stable product quality and the like. However, the method is accompanied with the production of a large amount of other byproducts in the preparation of pentaerythritol, so that the purity of the pentaerythritol is reduced and the acetal content is high; moreover, the automation degree is low when the pentaerythritol is prepared, the labor intensity and the personnel intensity are high, and the preparation method in the patent not only reduces the production efficiency of the pentaerythritol, but also increases the investment of the production cost.
Disclosure of Invention
The invention provides a production system and a production process of grade 99 pentaerythritol, aiming at overcoming the defects in the prior art and solving the problems in the background technology.
The invention is realized by the following technical scheme: a production system of 99-grade pentaerythritol comprises a feeding unit, a reaction unit, a dealdehyding unit, a dealcoholizing unit, an evaporation unit, a crystallization unit, a centrifugal unit and a drying unit which are sequentially arranged;
the feeding unit comprises a dilute formaldehyde tank, a dilute formaldehyde pump, a concentrated formaldehyde tank, a concentrated formaldehyde pump, a liquid alkali tank, a liquid alkali pump, an acetaldehyde tank, an acetaldehyde pump, a process water tank and a process water pump; the diluted formaldehyde and concentrated formaldehyde are compounded into bottom water, which is fed into condensation kettle together with water diluted liquid alkali and water diluted acetaldehyde.
The reaction unit comprises a first-stage reaction kettle, a first-stage reaction kettle discharge pump, a second-stage reaction kettle discharge pump, a third-stage reaction kettle discharge pump, a fourth-stage reaction kettle discharge pump, a neutralization tank discharge pump and a condensation liquid tank which are sequentially connected in series;
four reaction kettles are connected in series, so that the back mixing degree is reduced on one hand, and the reaction temperatures in different stages need to be controlled on the other hand due to the chemical reaction mechanism, so that the production requirement of products is met. The temperature of the materials in a single reaction kettle is basically consistent, a plurality of reaction kettles are coupled and connected in series, and the reaction temperature of each stage can be accurately controlled by different reaction kettles.
Meanwhile, a plurality of reaction kettles are connected in series and can be regarded as an approximate plug flow reactor, and the conversion rate under the same working condition is higher than that of a single-kettle reactor, so that the conversion rate of the reaction is improved and the production continuity is realized by connecting the four reaction kettles in series.
The aldehyde removal unit comprises an aldehyde removal tower feed pump, a condensation liquid preheating tube nest and an aldehyde removal tower which are sequentially connected in series;
the dealcoholization unit comprises an alcohol-containing dilute formaldehyde tank, a dealcoholization tower feed pump, a dealcoholization tower and a methanol tank which are sequentially connected in series;
the evaporation unit comprises a flash evaporator, a condenser, a vacuum pump set, a primary evaporation discharge pump, a normal pressure evaporator and a secondary evaporation discharge pump which are sequentially connected in series;
the crystallization unit comprises a cooling OSLO crystallizer, a crystallization discharge pump and a centrifugal intermediate tank which are sequentially connected in series;
the cooling OSLO crystallizer cools saturated feed liquid through an external cooler to reach a specific supersaturation degree, then the saturated feed liquid enters a suspension bed through a vertical pipeline to enable crystals to grow, larger particles can quickly contact supersaturated solution, so the crystals can grow faster, and in addition, the particle size classification effect of a special crystallization chamber is added, the crystals produced by the OSLO crystallizer have the characteristics of large crystal size, narrow particle distribution and uniformity, and meanwhile, the continuous operation can be realized, and the labor intensity is reduced.
The centrifugal unit comprises a centrifugal feed pump and a belt type vacuum filter which are sequentially connected in series;
the drying unit includes a tray dryer.
The improved disc type dryer is improved on the basis of an old disc type dryer, a bottom cooling disc is added, the integration of drying and cooling is realized, the possibility of exceeding the standard of moisture and dewing of materials is avoided, and meanwhile, a foundation is laid for subsequent continuous automatic packaging.
The invention also discloses a production process of the 99-grade pentaerythritol, which comprises the following steps:
s1: putting formaldehyde, acetaldehyde and liquid caustic soda into a four-stage series kettle type reactor in a reaction unit through a feeding unit to carry out condensation reaction to obtain a mixed component; the mixed components flow into a neutralization kettle and are adjusted to proper pH value by formic acid to obtain condensation liquid; the feeding proportion and the temperature are automatically controlled by a DCS system;
s2: preheating the condensation liquid, wherein dilute formaldehyde containing alcohol is used as a heat source in the preheating process, then conveying the preheated condensation liquid to an aldehyde removal tower in an aldehyde removal unit, removing most of formaldehyde (the removal rate is 99.4-99.9%) and 52-57% of water in the condensation liquid, and then conveying the condensation liquid to a pentaerythritol negative pressure evaporator; separating the alcohol-containing dilute formaldehyde into methanol and dilute formaldehyde through a dealcoholization tower, and feeding the dilute formaldehyde for recycling;
s3: carrying out negative pressure flash evaporation on pentaerythritol obtained in S2 through an evaporation unit, evaporating a pentaerythritol mixed solution obtained from a tower kettle of the aldehyde removing tower to 88-94 ℃, evaporating through a normal pressure evaporator, taking secondary steam at the tower top of the aldehyde removing tower as a heat source, and finally obtaining an evaporated solution with the specific gravity of 1.3;
s4: conveying the evaporated liquid to a cooling OSLO crystallizer in a crystallization unit, continuously cooling and crystallizing, and transferring the crystallized liquid to a centrifugal intermediate tank;
s5: and continuously centrifuging the crystallized liquid through a belt type vacuum filter in a centrifugal unit, and continuously drying the centrifuged material by using a disc type dryer in a drying unit to obtain a 99-grade pentaerythritol finished product.
Preferably, in step S1: the molar concentration of the liquid caustic soda is 20%, the molar concentration of formaldehyde is 20%, and the molar concentration of acetaldehyde is 25%. The residence time of the mixed components in the first-stage reaction kettle, the second-stage reaction kettle, the third-stage reaction kettle and the fourth-stage reaction kettle is 30-40 min.
Preferably, in step S1: adjusting the pH value of the condensation liquid to 6.4-6.8 by formic acid. The temperatures of the first-stage reaction kettle, the second-stage reaction kettle, the third-stage reaction kettle and the fourth-stage reaction kettle are respectively controlled to be 22-27 ℃, 28-33 ℃, 32-37 ℃ and 38-43 ℃. The formaldehyde, the acetaldehyde and the liquid alkali are fed into a reaction unit according to a feeding ratio of 9.5:1: 1.15.
The invention has the beneficial effects that: the production system and the production process of the 99-grade pentaerythritol adopt a sodium method to continuously produce pentaerythritol, the pentaerythritol takes formaldehyde and acetaldehyde as raw materials to carry out condensation reaction under the catalysis of liquid alkali, the reaction stops in the middle, and is neutralized by formic acid, thus pentaerythritol and byproduct sodium formate are generated, then the 99-grade pentaerythritol finished product is obtained through the working procedures of aldehyde removal, dealcoholization, evaporation, crystallization, separation, drying and the like, and the mother liquor is settled and filtered to remove the sodium formate. By adding formaldehyde, acetaldehyde and liquid alkali into a reaction unit according to a feeding proportion of 9.5:1:1.15, the invention can realize a co-production technology of mono-dipentaerythritol and can reduce the generation of byproducts, thereby improving the purity and yield of the obtained 99-grade pentaerythritol, and the formaldehyde removal rate of the aldehyde removal tower reaches 99%. The alcohol-containing dilute formaldehyde is used as a heat source, so that the utilization rate of heat energy is greatly improved, and the energy is saved. In addition, the invention has higher automation degree when producing the pentaerythritol, has smaller labor intensity and personnel concentration compared with the production process in the prior art, simultaneously improves the production efficiency of the pentaerythritol and reduces the investment of the production cost. The production process disclosed by the invention can produce 99-grade pentaerythritol with the content of 99% by adopting one-step continuous production, and the acetal content of the finished pentaerythritol product is lower, so that the production equipment and the production process of the pentaerythritol belong to advanced levels at home.
Drawings
FIG. 1 is a schematic diagram of a 99-grade pentaerythritol production system according to the present invention;
FIG. 2 is a process flow diagram of a 99-grade pentaerythritol production process according to the present invention;
in fig. 1: 1-feeding unit; 2-a reaction unit; 3-a dealdehyding unit; 4-a dealcoholization unit; 5-an evaporation unit; 6-a crystallization unit; 7-a centrifugal unit; 8-a drying unit; 9-dilute formaldehyde tank; 10-dilute formaldehyde pump; 11-concentrated formaldehyde tank; 12-concentrated formaldehyde pump; 13-liquid caustic bath; 14-liquid caustic pump; a 15-acetaldehyde tank; a 16-acetaldehyde pump; 17-a process water tank; 18-a process water pump; 19-a first-stage reaction kettle; 20-a first-stage reaction kettle discharge pump; 21-a second-stage reaction kettle; 22-a discharge pump of the secondary reaction kettle; 23-a third-stage reaction kettle; 24-a discharge pump of the third-stage reaction kettle; 25-fourth-stage reaction kettle; 26-a fourth-stage reaction kettle discharge pump; 27-a neutralization tank; 28-a neutralization tank discharge pump; 29-a condensation liquid bath; 30-a feed pump of the aldehyde removal tower; 31-preheating the tube array by using the condensation liquid; 32-a formaldehyde removal column; 33-alcohol-containing dilute formaldehyde tank; 34-dealcoholization column feed pump; 35-a dealcoholization tower; 36-methanol tank; 37-a flash evaporator; 38-a condenser; 39-vacuum pump group; 40-first-stage evaporation discharge pump; 41-normal pressure evaporator; 42-a secondary evaporation discharge pump; 43-cooled OSLO crystallizer; 44-a crystallization discharge pump; 45-centrifugal intermediate tank; 46-centrifugal feed pump; 47-belt vacuum filter; 48-tray dryer.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
Example 1: a production process of grade 99 pentaerythritol comprises the following steps:
s1: feeding formaldehyde, acetaldehyde and liquid alkali into a four-stage series kettle type reactor in a reaction unit 2 for condensation reaction through a feeding unit 1 according to a feeding ratio of 9.5:1:1.15 to obtain a mixed component; wherein the temperatures of the first-stage reaction kettle 19, the second-stage reaction kettle 21, the third-stage reaction kettle 23 and the fourth-stage reaction kettle 25 are respectively controlled at 22 ℃, 28 ℃, 32 ℃ and 38 ℃; finally, the mixed components flow into a neutralization kettle and are adjusted to proper pH value by formic acid, so that condensation liquid is obtained; the feeding proportion and the temperature are automatically controlled by a DCS system;
s2: preheating the condensation liquid, using dilute formaldehyde containing alcohol as a heat source, conveying the preheated condensation liquid to an aldehyde removal tower 32 in an aldehyde removal unit 3, removing 99.4% of formaldehyde and 52% of water, and then conveying the condensation liquid to a pentaerythritol negative pressure evaporator; the alcohol-containing dilute formaldehyde passes through a dealcoholization unit 4 and a dealcoholization tower 35, methanol and dilute formaldehyde are separated, and the dilute formaldehyde is fed for recycling;
s3: carrying out negative pressure flash evaporation on pentaerythritol obtained in S2 through an evaporation unit 5, evaporating a pentaerythritol mixed solution obtained from the tower bottom of the aldehyde removing tower 32 to 88 ℃, evaporating the pentaerythritol mixed solution through a normal pressure evaporator 41, taking secondary steam at the tower top of the aldehyde removing tower as a heat source, and finally obtaining an evaporated solution with the specific gravity of 1.3;
s4: the evaporated liquid is conveyed to a cooling OSLO crystallizer 43 in the crystallization unit 6, and after continuous cooling crystallization, the crystallized liquid is transferred to a centrifugal intermediate tank 45;
s5: and continuously centrifuging the crystallized liquid through a belt type vacuum filter 47 in a centrifugal unit 7, and continuously drying the centrifuged material by using a disc type dryer 48 in a drying unit 8 to obtain a finished product of grade 99 pentaerythritol.
In S1, the retention time of the mixed components in the first-stage reaction kettle 19, the second-stage reaction kettle 21, the third-stage reaction kettle 23 and the fourth-stage reaction kettle 25 is 30 min; the pH of the condensation solution was adjusted to 6.4 with formic acid.
Example 1 results: 10m, centrifuging the 99 crystallization liquid to obtain 2.74 tons of finished 99-monopentaerythritol, with 99.4% of single-season content, 0.1% of double-season content, 0.8% of acetal content, 49.46% of hydroxyl groups, and water content: 0.04%, ash: 0.01%, chroma: 40, melting point: 261 ℃.
Example 2: a production process of grade 99 pentaerythritol comprises the following steps:
s1: feeding formaldehyde, acetaldehyde and liquid alkali into a four-stage series kettle type reactor in a reaction unit 2 for condensation reaction through a feeding unit 1 according to a feeding ratio of 9.5:1:1.15 to obtain a mixed component; wherein the temperatures of the first-stage reaction kettle 19, the second-stage reaction kettle 21, the third-stage reaction kettle 23 and the fourth-stage reaction kettle 25 are respectively controlled at 25 ℃, 30 ℃, 35 ℃ and 40 ℃; finally, the mixed components flow into a neutralization kettle and are adjusted to proper pH value by formic acid, so that condensation liquid is obtained; the feeding proportion and the temperature are automatically controlled by a DCS system;
s2: preheating the condensation liquid, using dilute formaldehyde containing alcohol as a heat source, conveying the preheated condensation liquid to a formaldehyde removal tower 32 in a formaldehyde removal unit 3, removing 99.6% of formaldehyde and 54% of water, conveying the solution to a pentaerythritol negative pressure evaporator, passing the dilute formaldehyde containing alcohol through a dealcoholization unit 4 through a dealcoholization tower 35, separating out methanol and dilute formaldehyde, and feeding the dilute formaldehyde for recycling;
s3: carrying out negative pressure flash evaporation on pentaerythritol obtained in S2 through an evaporation unit 5, evaporating a pentaerythritol mixed solution obtained from the tower bottom of an aldehyde removing tower 32 to 90 ℃, evaporating the pentaerythritol mixed solution through a normal pressure evaporator 42, taking secondary steam at the tower top of the aldehyde removing tower as a heat source, and finally obtaining an evaporated solution with the specific gravity of 1.3;
s4: the evaporated liquid is conveyed to a cooling OSLO crystallizer 43 in the crystallization unit 6, and after continuous cooling crystallization, the crystallized liquid is transferred to a centrifugal intermediate tank 45;
s5: and continuously centrifuging the crystallized liquid through a belt type vacuum filter 47 in a centrifugal unit 7, and continuously drying the centrifuged material by using a disc type dryer 48 in a drying unit 8 to obtain a finished product of grade 99 pentaerythritol.
In S1, the residence time of the mixed components in the first-stage reaction kettle 19, the second-stage reaction kettle 21, the third-stage reaction kettle 23 and the fourth-stage reaction kettle 25 is 35 min; the pH of the condensation solution was adjusted to 6.5 with formic acid.
Example 2 results: 10m, centrifuging the 99 crystallization liquid to obtain 2.75 tons of finished 99-monopentaerythritol, with 99.5% of single-season content, 0.1% of double-season content, 0.9% of acetal content, 49.49% of hydroxyl groups, and water content: 0.05%, ash content: 0.02%, chroma: 40, melting point: 261 ℃.
Example 3: a production process of grade 99 pentaerythritol comprises the following steps:
s1: feeding formaldehyde, acetaldehyde and liquid alkali into a four-stage series kettle type reactor in a reaction unit 2 for condensation reaction through a feeding unit 1 according to a feeding ratio of 9.5:1:1.15 to obtain a mixed component; wherein the temperatures of the first-stage reaction kettle 19, the second-stage reaction kettle 21, the third-stage reaction kettle 23 and the fourth-stage reaction kettle 25 are respectively controlled at 26 ℃, 31 ℃, 36 ℃ and 41 ℃; finally, the mixed components flow into a neutralization kettle and are adjusted to proper pH value by formic acid, so that condensation liquid is obtained; the feeding proportion and the temperature are automatically controlled by a DCS system;
s2: preheating the condensation liquid, using dilute formaldehyde containing alcohol as a heat source, conveying the preheated condensation liquid to an aldehyde removal tower in an aldehyde removal unit 3, removing 99.7 percent of formaldehyde and 56 percent of water, and then conveying the condensation liquid to a pentaerythritol negative pressure evaporator; the alcohol-containing dilute formaldehyde passes through a dealcoholization unit 4 and a dealcoholization tower 35, methanol and dilute formaldehyde are separated, and the dilute formaldehyde is fed for recycling;
s3: carrying out negative pressure flash evaporation on pentaerythritol obtained in S2 through an evaporation unit 5, evaporating a pentaerythritol mixed solution obtained from a tower kettle of the aldehyde removing tower to 92 ℃, evaporating the pentaerythritol mixed solution through a normal pressure evaporator 41, taking secondary steam at the tower top of the aldehyde removing tower as a heat source, and finally obtaining an evaporated solution with the specific gravity of 1.3;
s4: the evaporated liquid is conveyed to a cooling OSLO crystallizer 43 in the crystallization unit 6, and after continuous cooling crystallization, the crystallized liquid is transferred to a centrifugal intermediate tank 45;
s5: and continuously centrifuging the crystallized liquid through a belt type vacuum filter 47 in a centrifugal unit 7, and continuously drying the centrifuged material by using a disc type dryer 48 in a drying unit 8 to obtain a finished product of grade 99 pentaerythritol.
In S1, the residence time of the mixed components in the first-stage reaction kettle 19, the second-stage reaction kettle 21, the third-stage reaction kettle 23 and the fourth-stage reaction kettle 25 is 38 min; the pH of the condensation solution was adjusted to 6.7 with formic acid.
Example 3 results: 10m, centrifuging the 99 crystallization liquid to obtain 2.76 tons of finished 99-monopentaerythritol, with 99.5% of single-season content, 0.1% of double-season content, 0.9% of acetal content, 49.52% of hydroxyl groups, and water content: 0.03%, ash: 0.01%, chroma: 40, melting point: 261 ℃.
Example 4: a production process of grade 99 pentaerythritol comprises the following steps:
s1: feeding formaldehyde, acetaldehyde and liquid alkali into a four-stage series kettle type reactor in a reaction unit 2 for condensation reaction through a feeding unit 1 according to a feeding ratio of 9.5:1:1.15 to obtain a mixed component; wherein the temperatures of the first-stage reaction kettle 19, the second-stage reaction kettle 21, the third-stage reaction kettle 23 and the fourth-stage reaction kettle 25 are respectively controlled at 27 ℃, 33 ℃, 37 ℃ and 43 ℃; finally, the mixed components flow into a neutralization kettle and are adjusted to proper pH value by formic acid, so that condensation liquid is obtained; the feeding proportion and the temperature are automatically controlled by a DCS system;
s2: preheating the condensation liquid, using dilute formaldehyde containing alcohol as a heat source, conveying the preheated condensation liquid to an aldehyde removal tower in an aldehyde removal unit 3, removing 99.9% of formaldehyde and 57% of water, and then conveying the condensation liquid to a pentaerythritol negative pressure evaporator; the alcohol-containing dilute formaldehyde passes through a dealcoholization unit 4 and a dealcoholization tower 35, methanol and dilute formaldehyde are separated, and the dilute formaldehyde is fed for recycling;
s3: carrying out negative pressure flash evaporation on pentaerythritol obtained in S2 through an evaporation unit 5, evaporating pentaerythritol mixed solution obtained from a tower kettle of the aldehyde removing tower to 94 ℃, evaporating through a normal pressure evaporator 43, taking secondary steam at the tower top of the aldehyde removing tower as a heat source, and finally obtaining the evaporated liquid with the specific gravity of 1.3;
s4: the evaporated liquid is conveyed to a cooling OSLO crystallizer 43 in the crystallization unit 6, and after continuous cooling crystallization, the crystallized liquid is transferred to a centrifugal intermediate tank 45;
s5: and continuously centrifuging the crystallized liquid through a belt type vacuum filter 47 in a centrifugal unit 7, and continuously drying the centrifuged material by using a disc type dryer 48 in a drying unit 8 to obtain a finished product of grade 99 pentaerythritol.
In S1, the residence time of the mixed components in the first-stage reaction kettle 19, the second-stage reaction kettle 21, the third-stage reaction kettle 23 and the fourth-stage reaction kettle 25 is 40 min; in S1, the pH of the condensation solution was adjusted to 6.8 with formic acid.
Example 4 results: 10m, centrifuging the 99 crystallization liquid to obtain 2.76 tons of finished 99-monopentaerythritol, with 99.4% of single-season content, 0.1% of double-season content, 0.8% of acetal content, 49.56% of hydroxyl groups, and water content: 0.04%, ash: 0.02%, chroma: 40, melting point: 261 ℃.
Finally, it should be noted that the above-mentioned contents are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, and that the simple modifications or equivalent substitutions of the technical solutions of the present invention by those of ordinary skill in the art can be made without departing from the spirit and scope of the technical solutions of the present invention.
Claims (4)
1. A production system of grade 99 pentaerythritol is characterized in that: the production system comprises a feeding unit, a reaction unit, a dealdehyding unit, a dealcoholization unit, an evaporation unit, a crystallization unit, a centrifugal unit and a drying unit which are arranged in sequence;
the feeding unit comprises a dilute formaldehyde tank, a dilute formaldehyde pump, a concentrated formaldehyde tank, a concentrated formaldehyde pump, a liquid alkali tank, a liquid alkali pump, an acetaldehyde tank, an acetaldehyde pump, a process water tank and a process water pump;
the reaction unit comprises a first-stage reaction kettle, a first-stage reaction kettle discharge pump, a second-stage reaction kettle discharge pump, a third-stage reaction kettle discharge pump, a fourth-stage reaction kettle discharge pump, a neutralization tank discharge pump and a condensation liquid tank which are sequentially connected in series;
the aldehyde removing unit comprises an aldehyde removing tower feed pump, a condensation liquid preheating tube nest and an aldehyde removing tower which are sequentially connected in series;
the dealcoholization unit comprises an alcohol-containing dilute formaldehyde tank, a dealcoholization tower feed pump, a dealcoholization tower and a methanol tank which are sequentially connected in series;
the evaporation unit comprises a flash evaporator, a condenser, a vacuum pump set, a primary evaporation discharge pump, a normal pressure evaporator and a secondary evaporation discharge pump which are sequentially connected in series;
the crystallization unit comprises a cooling OSLO crystallizer, a crystallization discharge pump and a centrifugal intermediate tank which are sequentially connected in series;
the centrifugal unit comprises a centrifugal feed pump and a belt type vacuum filter which are sequentially connected in series;
the drying unit includes a tray dryer.
2. A production process for producing grade 99 pentaerythritol by using the grade 99 pentaerythritol production system according to claim 1, characterized in that: the production process specifically comprises the following steps:
s1: putting formaldehyde, acetaldehyde and liquid caustic soda into a four-stage series kettle type reactor in a reaction unit through a feeding unit to carry out condensation reaction to obtain a mixed component; the mixed components flow into a neutralization kettle and are adjusted to proper pH value by formic acid to obtain condensation liquid; the feeding proportion and the temperature are automatically controlled by a DCS (distributed control system);
s2: preheating the condensation liquid, wherein dilute formaldehyde containing alcohol is used as a heat source in the preheating process, then conveying the preheated condensation liquid to an aldehyde removal tower in an aldehyde removal unit, removing most of formaldehyde and 52-57% of water in the condensation liquid, and then conveying the condensation liquid to a pentaerythritol negative pressure evaporator; separating the alcohol-containing dilute formaldehyde into methanol and dilute formaldehyde through a dealcoholization tower, and feeding the dilute formaldehyde for recycling;
s3: carrying out negative pressure flash evaporation on pentaerythritol obtained in S2 through an evaporation unit, evaporating a pentaerythritol mixed solution obtained from a tower kettle of the aldehyde removing tower to 88-94 ℃, evaporating through a normal pressure evaporator, taking secondary steam at the tower top of the aldehyde removing tower as a heat source, and finally obtaining an evaporated solution with the specific gravity of 1.3;
s4: conveying the evaporated liquid to a cooling OSLO crystallizer in a crystallization unit, continuously cooling and crystallizing, and transferring the crystallized liquid to a centrifugal intermediate tank;
s5: continuously centrifuging the crystallized liquid through a belt type vacuum filter in a centrifugal unit, and continuously drying the centrifuged material by using a disc type dryer in a drying unit to obtain a 99-grade pentaerythritol finished product;
in the step S1: the temperatures of the first-stage reaction kettle, the second-stage reaction kettle, the third-stage reaction kettle and the fourth-stage reaction kettle are respectively controlled to be 22-27 ℃, 28-33 ℃, 32-37 ℃ and 38-43 ℃; the formaldehyde, the acetaldehyde and the liquid alkali are fed into a reaction unit according to a feeding ratio of 9.5:1: 1.15.
3. The production process according to claim 2, characterized in that: in the step S1: the residence time of the mixed components in the first-stage reaction kettle, the second-stage reaction kettle, the third-stage reaction kettle and the fourth-stage reaction kettle is 30-40 min.
4. The production process according to claim 2, characterized in that: in the step S1: adjusting the pH value of the condensation liquid to 6.4-6.8 by formic acid.
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| CN111499493A (en) * | 2020-03-31 | 2020-08-07 | 赤峰瑞阳化工有限公司 | Continuous condensation method and device for monopentaerythritol, dipentaerythritol and tripentaerythritol |
| CN112062659B (en) * | 2020-09-09 | 2023-04-07 | 赤峰瑞阳化工有限公司 | Method for producing tripentaerythritol with purity of more than 90 percent |
| CN112479816A (en) * | 2020-11-30 | 2021-03-12 | 安徽金禾实业股份有限公司 | Continuous condensation method of pentaerythritol |
| CN113845403B (en) * | 2021-11-30 | 2023-08-11 | 万华化学集团股份有限公司 | Preparation method for co-production of 2-methyl-1, 3-propanediol and pentaerythritol |
| CN114085127A (en) * | 2021-12-02 | 2022-02-25 | 赤峰瑞阳化工有限公司 | Crystallization separation method of pentaerythritol |
| CN114315517A (en) * | 2021-12-31 | 2022-04-12 | 赤峰瑞阳化工有限公司 | Production method of low-energy-consumption 98-grade pentaerythritol |
| CN115784844A (en) * | 2022-12-08 | 2023-03-14 | 赤峰瑞阳化工有限公司 | Method for recovering formaldehyde and methanol and removing macromolecular impurities by pentaerythritol multi-tower series high-efficiency rectification |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4612389A (en) * | 1981-11-18 | 1986-09-16 | Virginia Chemicals Inc. | Treatment of waste stream from pentaerythritol manufacture |
| CN101265166A (en) * | 2008-04-25 | 2008-09-17 | 江苏瑞阳化工股份有限公司 | Method for producing monopentaerythritol, bipentaerythritol and tripentaerythritol |
| CN102432431A (en) * | 2011-11-07 | 2012-05-02 | 贵州金江化工有限公司 | Method for increasing yield of mono-pentaerythritol |
| CN104230660A (en) * | 2014-09-27 | 2014-12-24 | 安徽金禾实业股份有限公司 | Method for preparing 95 grade pentaerythritol |
| CN105111047A (en) * | 2015-08-28 | 2015-12-02 | 安徽金禾实业股份有限公司 | Production method of Grade-99 pentaerythritol |
| CN105130765A (en) * | 2015-08-28 | 2015-12-09 | 安徽金禾实业股份有限公司 | Production method for 90-level dipentaerythritol |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE528572C2 (en) * | 2006-02-03 | 2006-12-19 | Perstorp Specialty Chem Ab | Preparation of monpentaerythritol comprises reacting formaldehyde with acetaldehyde and dissolving obtained pentaerythritol crystals in aqueous mother liquor and crystallizing |
-
2018
- 2018-12-28 CN CN201811622120.XA patent/CN109438182B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4612389A (en) * | 1981-11-18 | 1986-09-16 | Virginia Chemicals Inc. | Treatment of waste stream from pentaerythritol manufacture |
| CN101265166A (en) * | 2008-04-25 | 2008-09-17 | 江苏瑞阳化工股份有限公司 | Method for producing monopentaerythritol, bipentaerythritol and tripentaerythritol |
| CN102432431A (en) * | 2011-11-07 | 2012-05-02 | 贵州金江化工有限公司 | Method for increasing yield of mono-pentaerythritol |
| CN104230660A (en) * | 2014-09-27 | 2014-12-24 | 安徽金禾实业股份有限公司 | Method for preparing 95 grade pentaerythritol |
| CN105111047A (en) * | 2015-08-28 | 2015-12-02 | 安徽金禾实业股份有限公司 | Production method of Grade-99 pentaerythritol |
| CN105130765A (en) * | 2015-08-28 | 2015-12-09 | 安徽金禾实业股份有限公司 | Production method for 90-level dipentaerythritol |
Non-Patent Citations (1)
| Title |
|---|
| 高品质季戊四醇合成工艺的研究;滕冬成;《精细化工中间体》;20050630;第35卷(第3期);64-66页 * |
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Denomination of invention: A production system of 99 grade pentaerythritol and its production process Effective date of registration: 20220422 Granted publication date: 20210427 Pledgee: Chifeng Branch of China Construction Bank Co.,Ltd. Pledgor: CHIFENG RUIYANG CHEMICAL CO.,LTD. Registration number: Y2022150000032 |