CN112679350B - Recovery system of alcoholysis waste liquid - Google Patents
Recovery system of alcoholysis waste liquid Download PDFInfo
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- CN112679350B CN112679350B CN202011595787.2A CN202011595787A CN112679350B CN 112679350 B CN112679350 B CN 112679350B CN 202011595787 A CN202011595787 A CN 202011595787A CN 112679350 B CN112679350 B CN 112679350B
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Abstract
The invention relates to a recovery system of alcoholysis waste liquid, comprising: a methyl acetate crude separation column, a methyl acetate purification column connected with the methyl acetate crude separation column, a recovered methyl acetate storage tank connected with the methyl acetate purification column, a catalytic decomposition column connected with the recovered methyl acetate storage tank and the methyl acetate purification column, an acetic acid crude separation column connected with the methyl acetate crude separation column, the methyl acetate purification column, the recovered methyl acetate storage tank and the catalytic decomposition column, and an acetic acid crude separation column distillation tank connected with the acetic acid crude separation column, the methyl acetate purification column and the catalytic decomposition column. The scheme of the invention achieves the aim of reducing the consumption of circulating water and steam and reduces the production cost.
Description
Technical Field
The invention relates to a recovery system, in particular to a recovery system of alcoholysis waste liquid.
Background
The alcoholysis waste liquid from the tank area is sent to a methyl acetate crude separation tower, the methyl acetate crude separation tower is used for distilling crude methyl acetate, the methyl acetate distilled from the methyl acetate purification tower is sent to a methyl acetate purification tower, the methyl acetate distilled from the methyl acetate purification tower is sent to a methyl acetate recovery storage tank, the methyl acetate recovery storage tank is sent to a catalytic decomposition tower for hydrolysis reaction to generate acetic acid and methanol, the unreacted mixed solution of methyl acetate, acetic acid and methanol is sent to the acetic acid crude separation tower through the catalytic decomposition tower kettle, and the distilled product of the acetic acid crude separation tower is sent to the catalytic decomposition tower for hydrolysis after being rectified and purified again, and the distilled product of the catalytic decomposition tower is sent to the methyl acetate purification tower. The recovery process has low methyl acetate decomposition rate, a large amount of methyl acetate is repeatedly evaporated and condensed in the system, the consumption of circulating water and steam is high, and the production cost is high.
Thus, it has in particular the following drawbacks:
(1) the existing methyl acetate is firstly subjected to coarse separation by a methyl acetate coarse separation tower, then is sent to a methyl acetate purification tower for purification, and then is sent to a catalytic decomposition tower for reaction to generate acetic acid and methanol, and the hydrolysis reaction of the methyl acetate is a reversible reaction, so that the decomposition rate is about 45-60%, and a large amount of methyl acetate is repeatedly evaporated and condensed in a system, so that the consumption of circulating water and steam is high.
(2) The prior measures are to increase the decomposition rate of methyl acetate by increasing the water-to-ester ratio and the temperature of the catalytic decomposition tower, and the increase of the water-to-ester ratio means that the water adding amount is increased, which can cause the steam consumption of the acetic acid purification tower.
(3) The temperature of the catalytic decomposition tower is increased to cause large reflux quantity of the tower, the flow rate in the tower is high, the decomposition rate is reduced, or a large amount of methyl acetate is repeatedly evaporated and condensed in the system, so that the energy consumption is high.
(4) In the prior art, the top of the acetic acid crude separation tower is pressurized, and the gas phase at the top of the acetic acid crude separation tower is sent to the methyl acetate purification tower, so that the aim of reducing energy consumption is fulfilled, but in order to ensure the reflux quantity of the acetic acid crude separation tower, part of the gas phase is condensed into liquid through a distillation condenser and then is used as the reflux of the acetic acid crude separation tower, the gas phase quantity sent to the methyl acetate purification tower is limited, and the energy saving quantity is not obvious.
Disclosure of Invention
The invention aims to provide a recovery system of alcoholysis waste liquid, which solves the problem of high production cost.
In order to achieve the above object, the present invention provides a recovery system for an alcoholysis waste liquid, comprising: a methyl acetate crude separation column, a methyl acetate purification column connected with the methyl acetate crude separation column, a recovered methyl acetate storage tank connected with the methyl acetate purification column, a catalytic decomposition column connected with the recovered methyl acetate storage tank and the methyl acetate purification column, an acetic acid crude separation column connected with the methyl acetate crude separation column, the methyl acetate purification column, the recovered methyl acetate storage tank and the catalytic decomposition column, and an acetic acid crude separation column distillation tank connected with the acetic acid crude separation column, the methyl acetate purification column and the catalytic decomposition column.
According to one aspect of the invention, a first pipeline is arranged at the top of the methyl acetate coarse separation tower and is connected with the methyl acetate purification tower, and a second pipeline is arranged at the bottom of the methyl acetate coarse separation tower and is connected with the bottom of the methyl acetate purification tower.
According to one aspect of the invention, a third pipeline connected with the acetic acid crude separation column distillation tank is arranged on the first pipeline;
and a first valve group for controlling the flow rate of the third pipeline is arranged on the third pipeline.
According to one aspect of the invention, a fourth pipeline connected with the upper part of the recovered methyl acetate storage tank is arranged at the top of the methyl acetate purifying tower, and a fifth pipeline connected with the catalytic decomposition tower is arranged at the lower part of the recovered methyl acetate storage tank.
According to one aspect of the invention, a sixth pipeline for connecting with the third pipeline is arranged on the fifth pipeline;
and a second valve group for controlling the flow rate of the sixth pipeline is arranged on the sixth pipeline.
According to one aspect of the invention, a seventh pipeline is arranged at the top of the catalytic decomposition tower;
the seventh pipeline is provided with a first branch pipeline and a second branch pipeline, and the second branch pipeline is connected with the third pipeline;
and an eighth pipeline is arranged at the tower bottom of the catalytic decomposition tower and is connected with the acetic acid coarse separation tower.
According to one aspect of the invention, the first branch pipeline is provided with a third valve group for controlling the flow rate of the first branch pipeline, and the second branch pipeline is provided with a fourth valve group for controlling the flow rate of the second branch pipeline.
According to one aspect of the invention, a ninth pipeline connected with the methyl acetate purifying tower and a tenth pipeline connected with the upper part of the acetic acid crude separation tower distillation tank are arranged at the top of the acetic acid crude separation tower;
a fifth valve group for controlling the flow rate of the ninth pipeline is arranged on the ninth pipeline;
and a sixth valve group for controlling the flow rate of the tenth pipeline is arranged on the tenth pipeline.
According to one aspect of the invention, the lower part of the acetic acid crude separation column distillation tank is provided with an eleventh pipeline connected with the upper part of the acetic acid crude separation column and a twelfth pipeline connected with the first branch pipeline and the upper part of the methyl acetate purification column;
the eleventh pipeline is communicated with the twelfth pipeline.
According to one aspect of the invention, the sixth valve group is a pressurization regulating valve, and the opening degree of the sixth valve group is less than or equal to 10%.
According to the scheme of the invention, the effect of reducing the consumption of circulating water and steam is achieved, and the production cost is reduced.
According to the scheme of the invention, the methyl acetate rough separation tower, the methyl acetate recovery storage tank and the catalytic decomposition tower are arranged on the pipelines, so that the methyl acetate rough separation tower, the methyl acetate purification tower, the methyl acetate recovery storage tank and the catalytic decomposition tower are all connected with the acetic acid rough separation tower, and thus, the flow compensation is carried out on the acetic acid rough separation tower through each tower or device, the consumption of the whole system is effectively reduced under the condition of ensuring the normal operation of the whole device, and the production cost is greatly saved. Because the materials in the methyl acetate crude separation tower, the methyl acetate purification tower, the recovered methyl acetate storage tank, the catalytic decomposition tower and the acetic acid crude separation tower all contain methyl acetate and methanol, the difference is only that the contents of the two substances are different, by adopting the technical scheme of the invention, the acetic acid crude separation tower is supplemented by each tower or device, and the tower pressures of the methyl acetate purification tower and the acetic acid crude separation tower are respectively adjusted upwards by 15% -25% and 20% -25%, so that the operation of the acetic acid crude separation tower is not influenced, and the normal, stable and efficient operation of other towers can be ensured. By the arrangement, about 0.36 ton/ton of the polyvinyl alcohol can be saved in steam, about 8.2 ton/ton of the circulating water is saved, and if the annual output of the polyvinyl alcohol is 1 ten thousand tons, the direct economic benefit is about 18.2 ten thousand yuan/year.
According to the scheme of the invention, a pipeline (namely a third pipeline) for feeding the acetic acid crude separation tower to the distillation tank is newly added on the pipeline for feeding the acetic acid crude separation tower to the acetic acid purification tower to be used as reflux of the acetic acid crude separation tower, so that the amount of the gaseous phase of the acetic acid crude separation tower fed to the acetic acid purification tower can be directly increased, the steam usage amount of the acetic acid purification tower and the condensation amount of the gaseous phase of the acetic acid crude separation tower are reduced, and the beneficial effects of saving circulating water and steam are achieved. In addition, through being provided with the first valves of its flow of control on the third pipeline, the volume of the liquid phase of the coarse separation tower of regulation input acetic acid that still can be dynamic like this has fully guaranteed the dynamic balance under the whole device operating condition.
According to the scheme of the invention, a pipeline (namely a sixth pipeline) for feeding the methyl acetate to the distillation tank of the acetic acid crude separation tower is newly added on the pipeline for feeding the methyl acetate recovery tank to the catalytic decomposition tower, so that when the methyl acetate distilled from the methyl acetate crude separation tower cannot meet the reflux requirement of the acetic acid crude separation tower, the methyl acetate recovery tank can be fed to the distillation tank of the acetic acid crude separation tower for reflux, thereby ensuring the reflux quantity of the acetic acid crude separation tower, reducing the evaporation and condensation times of the methyl acetate and reducing the energy consumption. In addition, through being provided with the second valves of its flow of control on sixth pipeline, the flow in the pipeline of still can dynamic adjustment like this, fully guaranteed the dynamic balance under the whole device operating condition.
According to the scheme of the invention, a pipeline (namely a second branch pipeline) for feeding the methyl acetate distilled from the catalytic decomposition tower into the methyl acetate purifying tower is newly added on the pipeline for feeding the methyl acetate distilled from the crude acetic acid separating tower, so that when the methyl acetate distilled from the crude acetic acid separating tower cannot meet the reflux requirement of the crude acetic acid separating tower, the recovered methyl acetate storage tank and the recovered methyl acetate distilled from the catalytic decomposition tower can be fed into the methyl acetate distilled from the crude acetic acid separating tower for reflux, thereby ensuring the reflux quantity of the crude acetic acid separating tower, reducing the evaporation and condensation times of the methyl acetate and reducing the energy consumption.
Drawings
Fig. 1 schematically shows a structural view of a recovery system according to an embodiment of the present invention.
1 methyl acetate crude separation column, 2 methyl acetate purification column, 3 recovery methyl acetate storage tank, 4 catalytic decomposition column, 5 acetic acid crude separation column, 6 acetic acid crude separation column distillation tank, 11 first line, 12 second line, 13 third line, 131 first valve group, 21 fourth line, 31 fifth line, 32 sixth line, 321 second valve group, 41 seventh line, 41a first branch line, 41b second branch line, 411 third valve group, 412 fourth valve group, 42 eighth line, 51 ninth line, 52 tenth line, 511 fifth valve group, 521 sixth valve group, 61 eleventh line, 62 twelfth line
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.
In describing embodiments of the present invention, the terms "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in terms of orientation or positional relationship shown in the drawings for convenience of description and simplicity of description only, and do not denote or imply that the devices or elements in question must have a particular orientation, be constructed and operated in a particular orientation, so that the above terms are not to be construed as limiting the invention.
The present invention will be described in detail below with reference to the drawings and the specific embodiments, which are not described in detail herein, but the embodiments of the present invention are not limited to the following embodiments.
As shown in fig. 1, according to an embodiment of the present invention, a recovery system of an alcoholysis waste liquid of the present invention includes: a methyl acetate crude separation column 1, a methyl acetate purification column 2 connected to the methyl acetate crude separation column 1, a recovered methyl acetate storage tank 3 connected to the methyl acetate purification column 2, a catalytic decomposition column 4 connected to the recovered methyl acetate storage tank 3 and the methyl acetate purification column 2, an acetic acid crude separation column 5 connected to the methyl acetate crude separation column 1, the methyl acetate purification column 2, the recovered methyl acetate storage tank 3, the catalytic decomposition column 4, and an acetic acid crude separation column distillation tank 6 connected to the acetic acid crude separation column 5, the methyl acetate purification column 2, and the catalytic decomposition column 4.
As shown in fig. 1, according to one embodiment of the present invention, a first pipeline 11 is arranged at the top of the methyl acetate crude separation tower 1 and is connected with the tower body of the methyl acetate purification tower 2, and a second pipeline 12 is arranged at the tower bottom and is connected with the tower bottom of the methyl acetate purification tower 2. In this embodiment, the body of the methyl acetate crude separation column 1 is further provided with a pipe for receiving the alcoholysis waste liquid of the upstream tank zone. And the second pipeline of the tower kettle sends tower kettle liquid to the methanol purification tower for treatment.
As shown in fig. 1, according to an embodiment of the present invention, a third pipe 13 connected to the acetic acid crude distillation tank 6 is provided in the first pipe 11. In the present embodiment, the third pipe 13 is provided with a first valve group 131 for controlling the flow rate thereof.
Through the arrangement, on the pipeline of the methyl acetate crude separation tower 1 for distilling and feeding the methyl acetate purification tower 2, a pipeline (namely a third pipeline 13) for feeding the acetic acid crude separation tower distillation tank 6 is additionally arranged to be used as reflux of the acetic acid crude separation tower 5, so that the quantity of the gas phase of the acetic acid crude separation tower 5 fed to the methyl acetate purification tower 2 can be directly increased, the steam usage amount of the methyl acetate purification tower 2 and the condensation quantity of the gas phase of the acetic acid crude separation tower 5 are reduced, and the beneficial effects of saving circulating water and steam are achieved. In addition, the first valve group 131 for controlling the flow rate of the third pipeline 13 is arranged on the third pipeline, so that the amount of liquid phase input into the acetic acid rough separation tower 5 can be dynamically regulated, and the dynamic balance of the whole device in the working state is fully ensured.
As shown in fig. 1, according to an embodiment of the present invention, the top of the methyl acetate purifying column 2 is provided with a fourth pipe 21 connected to the upper part of the methyl acetate recovery tank 3, and the lower part of the methyl acetate recovery tank 3 is provided with a fifth pipe 31 connected to the body of the catalytic decomposition column 4. In the present embodiment, the fifth pipe 31 is provided with a sixth pipe 32 for connecting to the acetic acid crude distillation column 6. In the present embodiment, the sixth pipe 32 is provided with a second valve group 321 for controlling the flow rate thereof.
Through the arrangement, a pipeline (namely, a sixth pipeline 32) for conveying the methyl acetate distilled from the acetic acid coarse separation tower to the distillation tank 6 is newly added on the pipeline for conveying the methyl acetate recovered storage tank 3 to the catalytic decomposition tower 4, so that when the methyl acetate distilled from the methyl acetate coarse separation tower 1 cannot meet the reflux requirement of the acetic acid coarse separation tower 5, the methyl acetate recovered storage tank 3 can be conveyed to the distillation tank 6 for compensating reflux, thereby ensuring the reflux quantity of the acetic acid coarse separation tower 5, reducing the evaporation and condensation times of the methyl acetate and reducing the energy consumption. In addition, the second valve group 321 for controlling the flow rate is arranged on the sixth pipeline 32, so that the flow rate in the pipeline can be dynamically regulated, and the dynamic balance of the whole device in the working state is fully ensured.
As shown in fig. 1, according to an embodiment of the present invention, the top of the catalytic decomposition column 4 is provided with a seventh pipe 41. In the present embodiment, the seventh pipe 41 is provided with a first branch pipe 41a and a second branch pipe 41b, wherein the second branch pipe 41b is connected to the third pipe 13. In the present embodiment, the first branch pipe 41a is provided with a third valve group 411 for controlling the flow rate, and the second branch pipe 41b is provided with a fourth valve group 412 for controlling the flow rate. In the present embodiment, the bottom of the catalytic decomposition column 4 is provided with an eighth pipe 42 connected to the body of the acetic acid crude separation column 5.
Through the arrangement, a pipeline (namely a second branch pipeline 41 b) for feeding the methyl acetate into the methyl acetate purifying tower 2 is newly added on the pipeline for feeding the methyl acetate purifying tower 4 into the methyl acetate purifying tower, so that when the methyl acetate distilled from the methyl acetate coarse dividing tower 1 cannot meet the reflux requirement of the methyl acetate coarse dividing tower, the recovered methyl acetate storage tank 3 and the methyl acetate distilled from the catalytic decomposing tower 4 can be fed into the methyl acetate coarse dividing tower distilling tank 6 for reflux, thereby ensuring the reflux quantity of the methyl acetate coarse dividing tower 5, reducing the evaporation and condensation times of the methyl acetate and reducing the energy consumption.
As shown in fig. 1, according to an embodiment of the present invention, the top of the acetic acid crude separation column 5 is provided with a ninth pipe 51 for connection to the upper portion of the methyl acetate purification column 2 and a tenth pipe 52 for connection to the upper portion of the acetic acid crude separation column distillation tank 6. In the present embodiment, a fifth valve block 511 for controlling the flow rate of the ninth pipe 51 is provided in the ninth pipe 51; the tenth pipe 52 is provided with a sixth valve group 521 for controlling the flow rate thereof.
In the embodiment, the unified connection of the third pipeline 13 realizes that the materials in other towers supplement the materials in the acetic acid coarse separation tower 5, and simultaneously, the consumption of the pipeline is effectively saved, the construction cost of the pipeline is reduced, and the energy loss of the materials conveyed in the pipeline is also reduced.
As shown in fig. 1, according to an embodiment of the present invention, the lower portion of the acetic acid crude separation column distillation tank 6 is provided with an eleventh pipe 61 for connecting with the upper portion of the acetic acid crude separation column 5, and a twelfth pipe 62 for connecting with the first branch pipe 41a, the upper portion of the methyl acetate purification column 2. In the present embodiment, the eleventh pipe 61 and the twelfth pipe 62 communicate. Through the arrangement, the twelfth pipeline 62 is connected with the first branch pipeline 41a and the methyl acetate purifying tower 2, so that the simultaneous communication of the catalytic decomposition tower 4 and the acetic acid crude separation tower distillation tank 6 with the methyl acetate purifying tower 2 is realized, the pipeline usage amount in the pipeline is effectively saved, the reflux amount of the methyl acetate purifying tower is increased, and the work stability of the methyl acetate purifying tower and the logistics supply to other downstream towers are ensured.
As shown in FIG. 1, according to one embodiment of the present invention, the acetic acid crude separation column 5 has a top pressurization regulating valve (i.e., the sixth valve group 521 is kept slightly opened, and the opening degree of the regulating valve is less than or equal to 10%). Through the above arrangement, the sixth valve group 521 controls the flow rate of the acetic acid crude separation column condensate. The less the condensed vapor phase is fed to the top of the acetic acid crude separation column 5, the less the amount of circulating water is needed (the circulating water is used to exchange heat with the condenser), and the more the opposing vapor phase is fed to the methyl acetate purification column 2 (via the ninth line 51), the more the steam needed for the methyl acetate purification column 2 is saved.
As shown in FIG. 1, according to one embodiment of the present invention, the liquid level in the distillation tank 6 of the crude acetic acid separation column is regulated by a regulating valve for feeding the liquid phase in the methyl acetate purification column 2 from the distillation tank, and is 1-2m 3 And (3) sending the liquid-phase methyl acetate to the methyl acetate purification tower 2 per hour, if the flow rate of the methyl acetate crude separation tower 1 distilled out and sent to the acetic acid crude separation tower distilled out tank 6 is insufficient, the liquid-phase regulating valve of the methyl acetate purification tower 2 sent to the acetic acid crude separation tower distilled out tank 6 is fully closed, and if the liquid level of the acetic acid crude separation tower distilled out tank 6 still continuously drops, the regulating valve for recovering the methyl acetate storage tank 3 or the methyl acetate distilled out from the catalytic decomposition tower 4 and sending the methyl acetate to the acetic acid crude separation tower distilled out tank 6 is required to be opened for backflow, thereby ensuring the reflux rate of the acetic acid crude separation tower 5 and reducing the consumption of hot water and steam.
To further illustrate the present solution, a further description is given of the workflow of the present solution.
The alcoholysis waste liquid (the components are methyl acetate and methanol, the content of the methyl acetate is 30-40%, the temperature is 20-30 ℃) of the feed material of the methyl acetate crude separation tower 1 comes from a tank area, the waste liquid enters the methyl acetate crude separation tower 1 from the middle part or the middle upper part of the methyl acetate crude separation tower 1, the methanol discharged from the kettle of the methyl acetate crude separation tower 1 is sent to a methanol purification tower for treatment, one part of distilled crude methyl acetate (the content of the methyl acetate is 65-80%, the temperature is 55-60 ℃) is sent to a methyl acetate purification tower 2 for re-purification, the other part is sent to an acetic acid crude separation tower distillation tank 6 through a third pipeline 13, and the output flow is controlled through a first valve group 131.
The feed to the methyl acetate purification column 2 has three parts: firstly, the crude methyl acetate at the top of the methyl acetate crude separation tower 1 (the content of the methyl acetate is 65-80 percent, the temperature is 56-65 ℃), secondly, the methyl acetate and the methanol at the top of the catalytic decomposition tower 4 (the temperature is 50-65 ℃), and thirdly, the methyl acetate and the methanol at the top of the acetic acid crude separation tower 5 (the temperature is 58-65 ℃). The methyl acetate purified by the methyl acetate purifying tower 2 (the temperature after condensation is 30-40 ℃) is sent to a recovered methyl acetate storage tank 3 through a fourth pipeline 21, ABC is arranged in the recovered methyl acetate storage tank 3, the recovered methyl acetate storage tank 3 is mainly used as the material for the catalytic decomposition tower 4 through a fifth pipeline 31, and a sixth pipeline 32 is connected with the fifth pipeline 13 and is used as a standby pipeline for the material for the acetic acid crude separation tower distillation tank 6.
The main working principle of the catalytic decomposition tower 4 is that methyl acetate and desalted water are hydrolyzed into acetic acid and methanol under the action of a catalyst, the methyl acetate and the methanol (the temperature after condensation is 30-40 ℃) at the top of the catalytic decomposition tower 4 are sent to the methyl acetate purifying tower 2 through a first branch pipeline 41a, and the top sending flow is controlled through a third valve group 411; the top part is further sent to the acetic acid crude separation column distillation tank 6 through a newly added second branch pipeline 41b, the second branch pipeline 41b is connected with the fifth pipeline 13 and is used as a standby pipeline for feeding the acetic acid crude separation column distillation tank 6, and the fourth valve group 412 is used as a flowmeter to send out monitoring flow. Acetic acid, methanol and unhydrolyzed methyl acetate (the temperature is 70-80 ℃) which are generated by hydrolysis are sent to the acetic acid rough separation tower 5 through an eighth pipeline 42 of the bottom liquid of the catalytic decomposition tower.
The raw materials of the acetic acid coarse separation tower 5 are kettle liquid (the temperature is 70-80 ℃) of the catalytic decomposition tower 4, the main purpose is to initially separate acetic acid from methyl acetate and methanol, and one path of methyl acetate and methanol gas phase (the temperature is 220-250 ℃) at the top of the acetic acid coarse separation tower 5 is sent to the methyl acetate purification tower 2 through a ninth pipeline 51, and the gas phase sending quantity is controlled through a fifth valve bank 511; the other path is condensed by a condenser through a tenth pipeline 52 and then is sent to an acetic acid crude separation column distillation tank 6, and the top pressure of the acetic acid crude separation column 5 is controlled through a sixth valve group 521, namely the amount sent to the acetic acid crude separation column distillation tank 6 is controlled; delivering the dilute acetic acid in the kettle liquid to an acetic acid purifying tower for purification. The acetic acid crude separation column distillation tank 6 is fed from the third pipeline 13, the sixth pipeline 32, the second branch pipeline 41b and the tenth pipeline 52, and is returned to the acetic acid crude separation column 5 through an eleventh pipeline 61 to be used as reflux, and is fed through a twelfth pipeline 62 to be used as feed (the temperature is 30-45 ℃) of the methyl acetate purification column 2. Because the materials in the methyl acetate crude separation tower 1, the methyl acetate purification tower 2, the methyl acetate recovery storage tank 3, the catalytic decomposition tower 4 and the acetic acid crude separation tower 5 all contain methyl acetate and methanol, the difference is only that the contents of the two substances are different, by adopting the technical scheme of the invention, the acetic acid crude separation tower is supplemented by each tower or device, and simultaneously the tower pressures of the methyl acetate purification tower 2 and the acetic acid crude separation tower 5 are respectively adjusted upwards by 15% -25% and 20% -25%, the operation of the acetic acid crude separation tower 5 is not affected, and the normal, stable and efficient operation of other towers can be ensured. By the arrangement, about 0.36 ton/ton of the polyvinyl alcohol can be saved in steam, about 8.2 ton/ton of the circulating water is saved, and if the annual output of the polyvinyl alcohol is 1 ten thousand tons, the direct economic benefit is about 18.2 ten thousand yuan/year.
The foregoing is merely exemplary of embodiments of the invention and, as regards devices and arrangements not explicitly described in this disclosure, it should be understood that this can be done by general purpose devices and methods known in the art.
The above description is only one embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. A recovery system for an alcoholysis waste stream, comprising: a methyl acetate crude separation column (1), a methyl acetate purification column (2) connected to the methyl acetate crude separation column (1), a recovered methyl acetate storage tank (3) connected to the methyl acetate purification column (2), a catalytic decomposition column (4) connected to the recovered methyl acetate storage tank (3) and the methyl acetate purification column (2), an acetic acid crude separation column (5) connected to the methyl acetate crude separation column (1), the methyl acetate purification column (2), the recovered methyl acetate storage tank (3) and the catalytic decomposition column (4), an acetic acid crude separation column distillation tank (6) connected to the acetic acid crude separation column (5), the methyl acetate purification column (2) and the catalytic decomposition column (4);
a first pipeline (11) is arranged at the top of the methyl acetate crude separation tower (1) and is connected with the methyl acetate purification tower (2);
a third pipeline (13) connected with the acetic acid crude separation tower distillation tank (6) is arranged on the first pipeline (11); the third pipeline (13) is provided with a first valve group (131) for controlling the flow rate of the third pipeline;
a fifth pipeline (31) connected with the catalytic decomposition tower (4) is arranged at the lower part of the methyl acetate recovery tank (3);
a sixth pipeline (32) used for being connected with the third pipeline (13) is arranged on the fifth pipeline (31); the sixth pipeline (32) is provided with a second valve group (321) for controlling the flow rate of the sixth pipeline;
a seventh pipeline (41) is arranged at the top of the catalytic decomposition tower (4); the seventh pipeline (41) is provided with a first branch pipeline (41 a) and a second branch pipeline (41 b), and the second branch pipeline (41 b) is connected with the third pipeline (13);
a tenth pipeline (52) used for being connected with the upper part of the acetic acid crude separation tower distillation tank (6) is arranged at the top of the acetic acid crude separation tower (5); a sixth valve group (521) for controlling the flow rate of the tenth pipeline (52) is arranged on the tenth pipeline; a ninth pipeline (51) connected with the methyl acetate purifying tower (2) is further arranged at the top of the acetic acid coarse separation tower (5);
an eleventh pipeline (61) connected with the upper part of the acetic acid crude separation tower (5) and a twelfth pipeline (62) connected with the first branch pipeline (41 a) and the upper part of the methyl acetate purification tower (2) are arranged at the lower part of the acetic acid crude separation tower distillation tank (6);
the eleventh pipeline (61) and the twelfth pipeline (62) are communicated;
when the acetic acid coarse separation tower is supplemented by each tower or device, the tower pressure of the methyl acetate purifying tower (2) is adjusted by 15-25%, and the tower pressure of the acetic acid coarse separation tower (5) is adjusted by 20-25%.
2. The recovery system according to claim 1, characterized in that the column bottom of the methyl acetate crude separation column (1) is provided with a second pipeline (12) connected with the column bottom of the methyl acetate purification column (2).
3. A recovery system according to claim 2, characterized in that the top of the methyl acetate purification column (2) is provided with a fourth pipe (21) connected to the upper part of the recovered methyl acetate storage tank (3).
4. A recovery system according to claim 3, characterized in that the bottom of the catalytic decomposition column (4) is provided with an eighth pipe (42) connected to the acetic acid crude separation column (5).
5. The recovery system according to claim 4, wherein the first branch pipe (41 a) is provided with a third valve group (411) for controlling the flow rate thereof, and the second branch pipe (41 b) is provided with a fourth valve group (412) for controlling the flow rate thereof.
6. The recovery system according to claim 5, characterized in that the ninth pipe (51) is provided with a fifth valve group (511) controlling the flow thereof.
7. The recovery system of claim 6, wherein the sixth valve bank (521) is a pressurization regulator valve having an opening of 10% or less.
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| CN103373919A (en) * | 2013-07-04 | 2013-10-30 | 天津大学 | Method and equipment for separating and recycling alcoholysis waste liquid in polyvinyl alcohol production |
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2020
- 2020-12-29 CN CN202011595787.2A patent/CN112679350B/en active Active
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| CN103113614A (en) * | 2013-02-28 | 2013-05-22 | 天津普莱化工技术有限公司 | PVA (Polyvinyl alcohol) energy-saving and consumption-reducing production new technology method |
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