Method for recovering potassium acetate from waste brine in production of isopropyl iononeTechnical Field
The invention relates to a method for recycling potassium acetate in waste brine, in particular to a method for recycling potassium acetate in waste water rich in potassium acetate in a condensation process in the production of isopropyl ionone from citral, and belongs to the technical field of chemical industry.
Technical Field
Potassium acetate is an important chemical agent, can be used in desiccant, transparent glass and pharmaceutical industry, can also be used as an anti-icing agent, is used in high-end snow-melting agents, is mainly used in the fields of highways, airports and the like, and is free of corrosion to infrastructure and environment-friendly.
The existing technology mostly adopts neutralization reaction of acetic acid and potassium hydroxide to prepare potassium acetate, and the recovery method of chemical byproducts is less, the product quality is lower, especially in the fields of essence and spice, the recovery difficulty is high due to objective reasons of small waste brine amount, complex components and the like of the byproducts caused by relatively small yield of single products, the waste brine is generally burnt or entrusted to third party treatment, the treatment cost is high, the resource waste is caused, and the technology is uneconomical and environment-friendly.
In the synthetic spice product, potassium hydroxide with high concentration is used as a catalyst of citral and butanone in the production process of the isomethyl ionone, waste brine of which the byproduct is high in concentration after neutralization of acetic acid is used after the reaction is finished, the waste brine is used as waste liquid incineration treatment cost is high, and potassium element in the waste brine has certain corrosiveness to the material of an incinerator.
Aiming at the problems existing in the prior art, a new process for recycling potassium acetate from waste brine is urgently needed, and the method can be used in the field of snow-melting agents, can be used for producing a high-end snow-melting agent supply market with low cost, and realizes the maximum economic benefit of waste liquid treatment.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to provide a method for recycling potassium acetate in waste brine produced by using the isomethyl ionone, which is suitable for industrial application by recycling high-quality potassium acetate from waste brine by adopting a novel stripping and crystallization phase coupling process, and has the advantages of simple operation, high product yield and the like, compared with the problem of poor treatment economy of the waste brine of the potassium acetate in the prior isomethyl ionone production technology.
In order to achieve the above object, the present invention adopts the following technical scheme:
the invention provides a method for recycling potassium acetate in waste brine from the production of isopropyl ionone, which comprises the following steps:
1) Taking waste salt water containing potassium acetate generated in the condensation process of the isomethyl ionone as a raw material, and removing organic matters through stripping treatment to obtain a potassium acetate aqueous solution with the organic matter content of less than 0.1 wt%;
2) Adding tartaric acid and an auxiliary agent into the potassium acetate aqueous solution in the step 1), heating and stirring until a clear solution is obtained;
3) Evaporating and concentrating the clarified solution in the step 2), standing for crystal growth, then cooling by a program to obtain crystal slurry, and centrifuging and drying to obtain potassium acetate.
In the invention, the waste salt water containing potassium acetate generated in the step 1) of the step of condensing the dimethyl ionone comprises 10-30% of potassium acetate, 0-3% of methanol, 0-5% of butanone and the balance of water, wherein the total mass of the waste salt water is 100%.
In the invention, the waste brine in the step 1) enters from the top of a stripping tower, the stripping treatment temperature is 60-90 ℃, preferably 60-85 ℃, and the organic matters in the waste brine are removed by stripping, wherein the organic matters mainly comprise methanol, butanone and the like, and the total content in the waste brine is usually 0-8wt%;
preferably, the feed volume space velocity of the spent brine is from 0.5 to 20h-1, preferably from 1 to 10h-1;
Discharging the stripped potassium acetate solution from the bottom of the stripping tower, wherein the organic matter content in the potassium acetate solution is reduced to below 0.1wt percent, preferably below 0.01wt percent, and the content of potassium acetate is increased to 40-50wt percent;
Preferably, the carrier gas used in the stripping treatment is water vapor, nitrogen, air, carbon dioxide or tunnel gas, preferably nitrogen, and the carrier gas enters from the bottom of the stripping tower, and the feeding volume space velocity of the carrier gas is 20-60h-1, preferably 20-40h-1.
In the present invention, the concentration of the tartaric acid added to the aqueous potassium acetate solution in the step 2) is 1000-20000ppm, preferably 3000-8000ppm;
In the invention, the auxiliary agent in the step 2) is one or more of povidone, hydroxy cellulose and polyvinyl ester, preferably povidone;
Preferably, the auxiliary agent is povidone, hydroxycellulose and polyvinyl ester with the molecular weight of 3000-60000.
Preferably, the adjuvant is added to the aqueous potassium acetate solution at a concentration of 50 to 500ppm, preferably 50 to 200ppm.
In the present invention, the temperature is 50-80 ℃, preferably 60-70 ℃ in the temperature rising and stirring of the step 2), and the stirring speed is 10-300r/min, preferably 30-100r/min.
In the invention, a crystallization process of evaporation-cooling coupling is adopted in the step 3), wherein the evaporation concentration is carried out in a program decompression mode;
preferably, the pressure of the program is gradually and linearly reduced from 0.1MPaG to 0.01MPaG during the decompression process;
More preferably, the depressurization time is from 0.5 to 3 hours, preferably from 0.8 to 2 hours, and the depressurization rate is from 0.04 to 0.12MPa/h.
Preferably, the concentration by evaporation is terminated at a concentration of potassium acetate in the solution of 50-70wt%, preferably 63-68wt%.
In the invention, in the crystal growing process in the step 3), the stirring is stopped, and then the timing is started, wherein the crystal growing time is 2-5 hours, preferably 3.5-5 hours, and the temperature is 40-65 ℃, preferably 45-50 ℃.
In the invention, the procedure cooling process in the step 3) is realized by a constant temperature bath, and the procedure cooling is realized by linearly cooling the temperature of the crystal growing to 0-15 ℃, preferably 5-10 ℃ and the cooling rate is 3-20 ℃, preferably 5-15 ℃.
In the present invention, the centrifugation in step 3) is carried out at a rotational speed of 2000 to 3000rpm, preferably 2500 to 3000rpm.
In the present invention, the drying in step 3) is performed by spray drying, wherein the inlet temperature is 120-150 ℃, preferably 120-135 ℃, and the outlet temperature is 50-60 ℃, preferably 55-60 ℃.
In the invention, the purity of the potassium acetate recovered by the method is more than 99.9 percent, and the recovery rate is more than 90 percent;
the potassium acetate is colorless diamond crystal, and the bulk density is 1.2-1.3g/mL;
the granularity of the potassium acetate particles is 100-500 meshes, wherein the proportion of 100-200 meshes is more than 92%, preferably more than 95%, and the granularity of the potassium acetate particles is preferably 100-200 meshes.
Compared with the prior art, the invention has the beneficial effects that:
1) The invention solves the problem of difficult treatment of high-concentration waste brine in the existing production technology of the isomethyl ionone, firstly, the invention adopts a steam stripping mode to remove organic matters in the waste brine, improves the crystal purity, and avoids the organic matters in the waste brine entering the ground surface along with rainwater to pollute the ground water when the waste brine is used as a snow-melting agent.
2) The invention also adds tartaric acid and auxiliary agent into the waste brine solution, wherein the tartaric acid can obviously promote the solubility of potassium acetate in water, change the charge distribution near the crystal nucleus in the microemulsion system, further promote and induce the growth of organic salt potassium acetate on the surface of the crystal nucleus, avoid forming clusters or overquick growth in the growth process, and obtain high-quality salt from the waste water through the control of crystal form. Meanwhile, the added auxiliary agent can form a micro-emulsion system with a small amount of residual organic matters in the wastewater under stirring, and the micro-emulsion system enables crystal nuclei in the crystallization process to be more dispersed and uniformly distributed, so that the stable interval of crystallization is widened, and the problems of poor product crystal form, low purity and deep color caused by inclusion of impurities due to unstructured crystallization in the crystallization are avoided. The coordination of tartaric acid and the auxiliary agent influences the nucleation and growth processes of potassium acetate crystals, and the potassium acetate crystals are finally expressed in a crystal form with high purity and a certain form, so that the purpose of recovering high-quality potassium acetate from waste liquid is achieved.
3) The invention adopts two distinct crystallization modes of evaporation and cooling to couple, thereby avoiding the problem of high energy consumption of pure evaporation crystallization, avoiding the problems of clusters and inclusions of salt in the crystallization process and the problem of deep color of the product caused by enrichment of chromogenic substances in crystal forms due to continuous heating of waste liquid.
4) The potassium acetate product recovered by the method has regular crystal form, higher quality purity and relatively higher bulk density, and can effectively prevent melted snow from freezing when being used as a snow-melting agent, and is harmless and environment-friendly to ground infrastructure.
Drawings
FIG. 1 is a scanning electron microscope crystal form diagram of potassium acetate crystals prepared in example 1.
Detailed Description
The present invention will be described in further detail with reference to the following examples, but the scope of the present invention is not limited to these examples.
The analysis and test method adopted by the embodiment of the invention comprises the following steps:
the gas chromatographic analysis conditions comprise Agilent gas chromatograph, RTX-WAX column, 50 deg.C for 5min, 10 deg.C/min for 80 deg.C for 5min, 10 deg.C/min for 100 deg.C for 5min, and 10 deg.C/min for 160 deg.C for 15min.
The ion chromatography analysis method comprises an ion chromatograph, a Wanton 883 type, a separation column IonPacAS-HC (4 mm is 250 mm), a column temperature of 40 ℃, a conductivity monitor, a mobile phase violation sodium carbonate solution of 5.0mmol/L, a flow rate of 1.0mL/min, a mobile phase of an inhibitor of 80mL/min phosphoric acid aqueous solution and a sample injection amount of 20uL.
The electron microscope scanning conditions were that the single crystal X-ray diffractometer (SXRD) was a CD Xcalibur Nova type X-ray single crystal diffractometer (oxford instruments, UK). At room temperature, the sample was scanned with Mo-ka radiation (λ=0.071 nm) over a range of θ=3.13° -26.37 °.
The embodiment of the invention adopts main raw material source information:
The waste brine containing potassium acetate is derived from a Mo Huayi methyl ionone pilot plant, which adopts citral and butanone as raw materials, and prepares the waste brine containing potassium acetate as a byproduct by neutralization of acetic acid after the reaction is finished by adopting a production process of preparing the isopropyl ionone under the catalysis of high-concentration potassium hydroxide;
Povidone, basf Kollidon series, commercially abbreviated as povidone K30 (molecular weight 44000-54000), povidone K25 (molecular weight 28000-34000), povidone K17 (molecular weight 7000-11000);
hydroxycellulose, i.e. Isman, cellulose CAB-553-0.4, molecular weight 20000;
polyvinyl ester, namely denuo polyvinyl ester with molecular weight of 80000;
Tartaric acid, hubei jusheng technology, purity >99%;
The other materials are common commercial materials unless otherwise specified.
Example 1
Recovering potassium acetate from waste brine of the production of the isomethyl ionone:
1) The diameter of the stripping tower is 30mm, a 1m high 5*5 Western-style packing is filled, waste water containing potassium acetate (26 wt% of potassium acetate, 2.6wt% of methanol and 3.7wt% of butanone) generated in the condensation process of the isopropyl ionone is taken as a raw material, the waste water continuously enters the stripping tower from the top of the tower at the volume space velocity of 10h-1, nitrogen enters the tower kettle at the volume space velocity of 20h-1, the operating temperature of the stripping tower is 65 ℃, the flow rate of liquid collected from the top of the tower after the stripping is 8.1mL/min, the composition of the waste water is 9.0% of butanone, 6.5% of methanol and 84.6% of water, and the flow rate of liquid collected from the tower kettle is 11.9mL/min, so that a potassium acetate aqueous solution (43.8 wt% of potassium acetate, 56.1wt% of water, 0.07wt% of butanone and 0.03wt% of methanol in the composition) with the organic content of less than 0.1wt% is obtained.
2) Adding 3500ppm of tartaric acid and 80ppm of povidone K30 into the potassium acetate aqueous solution, heating to 80 ℃ and stirring at the rotating speed of 80 r/min to obtain a clear solution;
3) The clarified solution of step 2) was gradually and linearly reduced from 0.1MPaG to 0.01MPaG over 2h by controlling the system pressure by a diaphragm pump at a rate of 0.045MPa/h, and the system was concentrated by evaporation to 67.2wt% potassium acetate. Stopping stirring, standing at 45deg.C for 3.5 hr, cooling to 12deg.C by constant temperature bath at a speed of 5deg.C/hr to obtain crystal slurry, centrifuging at 2800rpm, and spray drying (inlet temperature 130 deg.C and outlet temperature 55 deg.C) to obtain colorless diamond potassium acetate crystal (as shown in figure 1), with purity of 99.92%, recovery rate of 92.3%, bulk density of 1.2g/mL, and particle size of 100-400 mesh, wherein 100-200 mesh accounts for 96.7%.
Example 2
Recovering potassium acetate from waste brine of the production of the isomethyl ionone:
1) The diameter of the stripping tower is 30mm, a 1m high 5*5 Western-style packing is filled, waste water containing potassium acetate (14 wt% of potassium acetate, 1.8wt% of methanol and 2.3wt% of butanone) generated in the process of condensing the isopropyl ionone is taken as a raw material, the waste water is continuously fed into the stripping tower from the tower top at the volume space velocity of 2h-1, nitrogen gas is fed into the tower bottom at the volume space velocity of 40h-1, the operating temperature of the stripping tower is 85 ℃, the flow rate of liquid collected from the tower top after the stripping is 13.7mL/min, the composition is 3.4wt% of butanone, 2.6wt% of methanol and 94wt% of water are taken, the flow rate of liquid collected from the tower bottom is 6.3mL/min, and the potassium acetate aqueous solution (44.2 wt% of potassium acetate, 55.77wt% of butanone and 0.02wt% of methanol in the composition) with the organic content of less than 0.1wt% is obtained.
2) Adding 7000ppm of tartaric acid and 200ppm of povidone K25 into the potassium acetate aqueous solution, heating to 65 ℃ and stirring at a rotating speed of 100 revolutions per minute to obtain a clear solution;
3) The clarified solution of step 2) was gradually and linearly reduced from 0.1MPaG to 0.01MPaG over 1.2h by controlling the system pressure by a diaphragm pump at a rate of 0.075MPa/h, and the system was concentrated by evaporation to a potassium acetate content of 66.5wt%. Stopping stirring, standing at 50deg.C for 4.5 hr, cooling to 10deg.C by constant temperature bath to obtain crystal slurry, centrifuging at 2500rpm, spray drying at inlet temperature of 125deg.C and outlet temperature of 55deg.C to obtain colorless diamond potassium acetate crystal with purity of 99.94%, recovery rate of 93.4%, bulk density of 1.3g/mL, and particle size of 100-500 mesh, wherein 100-200 mesh accounts for 95.8%.
Example 3
Recovering potassium acetate from waste brine of the production of the isomethyl ionone:
1) The diameter of the stripping tower is 30mm, a 1m high 5*5 Western-style packing is filled, waste water containing potassium acetate (14 wt% of potassium acetate, 1.8wt% of methanol and 2.3wt% of butanone) generated in the condensation process of the isopropyl ionone is taken as a raw material, the waste water is continuously fed into the stripping tower from the top of the tower at a volume space velocity of 5h-1, nitrogen gas is fed into the tower from the tower bottom at a volume space velocity of 30h-1, the operating temperature of the stripping tower is 85 ℃, the flow rate of liquid collected from the top of the tower after the stripping is 13.7mL/min, the composition of the waste water is 3.4wt% of butanone, 2.6wt% of methanol and the flow rate of liquid collected from the tower bottom is 6.3mL/min, and a potassium acetate aqueous solution (44.2 wt% of potassium acetate, 55.77wt% of butanone and 0.02wt% of methanol in the composition) with the organic content of <0.1wt% is obtained.
2) 5000Ppm of tartaric acid and 140ppm of povidone K17 are added into the potassium acetate aqueous solution, the temperature is raised to 75 ℃ and the rotating speed is 40 revolutions per minute, and the mixture is stirred until a clear solution is obtained;
3) The clarified solution of step 2) was gradually and linearly reduced from 0.1MPaG to 0.01MPaG over 1h by controlling the system pressure by a diaphragm pump at a rate of 0.09MPa/h, and the system was concentrated by evaporation to a potassium acetate content of 64.8wt%. Stopping stirring, standing at 55deg.C for 5 hr, cooling to 10deg.C by constant temperature bath at a speed of 10deg.C/hr to obtain crystal slurry, centrifuging at 3000rpm, and spray drying (inlet temperature 130 deg.C and outlet temperature 55 deg.C) to obtain colorless diamond potassium acetate crystal with purity of 99.91%, recovery rate of 93.1%, bulk density of 1.3g/mL, and particle size of 100-300 mesh, wherein 100-200 mesh accounts for 97.2%.
Example 4
The process of example 1 was referred to, except that povidone was changed to equal amount of hydroxycellulose in step 2) and the other operations were unchanged, to obtain colorless potassium acetate solid having a purity of 98.92%, a recovery rate of 93.2%, a bulk density of 1.1g/mL, a particle size of 100-500 mesh, and a 100-200 mesh ratio of 93.6%.
Example 5
The process of example 1 was referred to, except that in step 2) povidone was changed to equivalent amount of polyvinyl ester, and other operations were unchanged, to obtain colorless potassium acetate solid having a purity of 98.75%, a recovery rate of 93.8%, a bulk density of 1.1g/mL, a particle size of 100-500 mesh, and a ratio of 100-200 mesh of 92.7%.
Comparative example 1
The process of reference example 2 is only different in that no povidone auxiliary agent is added in step 2), and other operations are unchanged, so that pale yellow potassium acetate solid is obtained, the purity is 96.4%, the recovery rate is 91.7%, the bulk density is 1.1g/mL, the particle size is 100-500 meshes, and the proportion of 100-200 meshes is 46.3%.
Comparative example 2
The process of example 2 is referred to, except that in step 2) the auxiliary tartaric acid is replaced by succinic acid of equal mass, and the other operations are unchanged, to obtain pale yellow potassium acetate solid with a purity of 93.7%, a recovery rate of 82.3%, a bulk density of 1.2g/mL, and a particle size of 100-500 mesh, wherein the ratio of 100-200 mesh is 35.6%.
Comparative example 3
The process of reference example 2 is only different in that no auxiliary tartaric acid is added in step 2), and other operations are unchanged, so that pale yellow potassium acetate solid is obtained, the purity is 92.4%, the recovery rate is 78.2%, the bulk density is 1.1g/mL, the particle size is 100-400 meshes, and the ratio of 100-200 meshes is 25.3%.
Comparative example 4
The process of example 2 was referred to, except that the stripping operation of step 1) was omitted and the potassium acetate-containing waste brine was directly used in step 2), the other operations were unchanged, to give a pale yellow potassium acetate solid having a purity of 91.6%, a recovery rate of 83.4%, a bulk density of 1.2g/mL, a particle size of 100-500 mesh, and a 100-200 mesh ratio of 43.1%.
Comparative example 5
The procedure of example 2 was followed except that the depressurization rate in step 3) was adjusted to 0.9MPa/h, and the other operations were unchanged, to obtain colorless potassium acetate solid having a purity of 99.63%, a recovery rate of 93.4%, a bulk density of 1.2g/mL, and a particle size of 100 to 500. Mu.m, wherein the 100 to 200. Mu.m was 89.6%.
Comparative example 6
The process of example 2 was referred to, except that the time for seeding in step 3) was adjusted to 0.05h, and the other operations were unchanged, to give colorless potassium acetate solid having a purity of 99.37%, a recovery rate of 87.6%, a bulk density of 1.2g/mL, and a particle size of 100 to 400 mesh, wherein the 100 to 200 mesh accounts for 91.3%.
Comparative example 7
The process of example 2 was referred to except that the cooling rate in step 3) was adjusted from 10℃to 60℃per hour, and the other operations were unchanged, to give a colorless potassium acetate solid having a purity of 96.24%, a recovery rate of 89.3%, a bulk density of 1.2g/mL, a particle size of 100 to 500 mesh, and a 100 to 200 mesh ratio of 54.7%.