CN115089990A - Device and method for recycling high-temperature wastewater from alcoholysis waste liquid through hot water self-coupling - Google Patents
Device and method for recycling high-temperature wastewater from alcoholysis waste liquid through hot water self-coupling Download PDFInfo
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- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
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Abstract
The invention relates to a hot water self-coupling utilization device and a method for recovering high-temperature waste water from alcoholysis waste liquid, wherein the hot water self-coupling utilization device for the high-temperature waste water comprises: the system comprises a methanol purification tower, a catalytic decomposition tower, a flash tank, a first reboiler, a methyl acetate purification tower, a cooler and a centrifugal pump; a tower kettle of the methanol purification tower is sequentially connected with the flash tank, the first reboiler and the catalytic decomposition tower through pipelines; the catalytic decomposition tower is connected with the methanol purification tower through a methyl acetate purification tower; the flash tank is connected with a centrifugal pump, a cooler and a methyl acetate purification tower in sequence through pipelines; after entering a flash tank, the high-temperature wastewater in the tower kettle of the methanol purification tower forms flash steam and flash tank drainage, and the flash steam exchanges heat with the material in the catalytic decomposition tower in a first reboiler and is cooled to form hot water; the hot water is converged with the drainage water of the flash tank, and the cooled water is obtained after the temperature of the cooler and then enters a methyl acetate purification tower. The self-coupling realizes the quality improvement, waste heat recovery, waste water recycling, energy saving and consumption reduction of the high-temperature waste water.
Description
The application is a divisional application entitled "high-temperature hot water comprehensive utilization device of polyvinyl alcohol waste liquid recovery system", and the application date is 12/29/2020 and application number is 202011595789.1.
Technical Field
The invention relates to the field of chemical industry, in particular to a device and a method for hot water self-coupling utilization of high-temperature wastewater recovered from alcoholysis waste liquid.
Background
The rectifying tower of a chemical enterprise is one of common devices, the rectifying tower of methanol is pressurized in the process of separating methanol from water, methanol steam is sent to other towers to be used as a heat source, high-temperature wastewater at the bottom is directly discharged into a trench, the water content of the part of wastewater is high, the COD is low, the water quality is good, the part of wastewater is directly discharged into the trench to cause energy waste, but the part of wastewater cannot be directly recycled. Such as a methanol purification tower in the recovery process of polyvinyl alcohol industry.
In the recovery procedure in the prior art, polyvinyl alcohol alcoholysis waste liquid is sent to a methyl acetate crude separation tower for crude separation, crude methyl acetate distilled from the methyl acetate crude separation tower is sent to a methyl acetate purification tower for extraction and refining, and refined methyl acetate distilled from the methyl acetate purification tower is sent to a catalytic decomposition tower for catalytic hydrolysis reaction to generate acetic acid and methanol; methanol is discharged from the kettle of the methyl acetate rough separation tower, a methanol water solution is discharged from the kettle of the methyl acetate purification tower and is sent to a methanol purification tower for purifying the methanol, gas phase refined methanol distilled out from the methanol purification tower is sent to a tank area after heat exchange of a reboiler of the methyl acetate rough separation tower, and hot water is discharged from the kettle of the methanol purification tower and is sent to a sewage treatment plant after feeding and heat exchange of the methyl acetate rough separation tower.
The equipment and the process have the following problems: 1. at present, high-temperature hot water (the temperature is 120-. 2. The alcoholysis mother liquor has PVA powder, causes alcoholysis mother liquor pipeline and plate heat exchanger easily to pollute and block up, and the supplied material of methyl acetate coarse separation tower is the alcoholysis mother liquor, therefore methyl acetate coarse separation tower plate and cauldron exit line also easily block up, need carry out the parking with a large amount of demineralized water and boil and wash, and the energy consumption is high, causes the energy waste, increases the blow off quantity.
Disclosure of Invention
The invention aims to provide a device and a method for hot water self-coupling utilization of high-temperature wastewater recovered from alcoholysis waste liquid.
In order to achieve the above object, the present invention provides a self-coupling device for recycling hot water from high temperature wastewater recovered from alcoholysis waste liquid, comprising: a methanol purification tower, a catalytic decomposition tower, a flash tank, a first reboiler, a methyl acetate purification tower, a cooler and a centrifugal pump;
the tower kettle of the methanol purification tower is sequentially connected with the flash tank, the first reboiler and the catalytic decomposition tower through pipelines; the catalytic decomposition tower is connected with the methanol purification tower through the methyl acetate purification tower;
the flash tank is connected with the centrifugal pump, the cooler and the methyl acetate purification tower in sequence through pipelines;
after entering the flash tank, the high-temperature wastewater in the tower kettle of the methanol purification tower forms flash steam and flash tank drainage, and the flash steam exchanges heat with the material in the catalytic decomposition tower in the first reboiler and is cooled to form hot water; and the hot water is converged with the drainage water of the flash tank, and the cooled water is obtained after the temperature of the cooler and then enters the methyl acetate purification tower.
According to one aspect of the invention, the device also comprises a methyl acetate crude separation tower and a horizontal heat exchanger;
the methyl acetate rough separation tower is respectively connected with the methanol purification tower, the methyl acetate purification tower, the cooler and the horizontal heat exchanger;
the horizontal heat exchanger is respectively connected with the flash tank, the methyl acetate rough separation tower and the centrifugal pump, and the horizontal heat exchanger is a tube type horizontal heat exchanger;
and feeding the polyvinyl alcohol alcoholysis waste liquid into the horizontal heat exchanger to exchange heat with the hot water, feeding the heat-exchanged polyvinyl alcohol alcoholysis waste liquid into the methyl acetate coarse separation tower, and cooling the hot water and then converging the cooled hot water with the drainage water of the flash tank.
According to one aspect of the invention, a tower kettle of the methanol purification tower is connected with an inlet of the flash tank by adopting a first pipeline;
the steam outlet of the flash tank is connected with the upper inlet of the first reboiler by a third pipeline;
an upper outlet of the first reboiler is connected with the lower part of the catalytic decomposition tower by a fourth pipeline;
the lower outlet of the first reboiler is connected with the first pipeline by adopting a fifth pipeline; and a first sewage discharge pipe for discharging sewage is arranged on the fifth pipeline.
According to one aspect of the invention, the system further comprises a second reboiler connected with the first reboiler in parallel, and the tower kettle of the catalytic decomposition tower is respectively connected with the lower inlets of the first reboiler and the second reboiler by a second pipeline; the upper inlet of the second reboiler is connected with a sixth pipeline which is used for being connected with an external steam source; and an upper outlet of the second reboiler is connected with the lower part of the catalytic decomposition tower by adopting a fourth pipeline.
According to one aspect of the invention, a seventh pipeline and an eighth pipeline are connected to a sewage discharge outlet of the flash tank, and the flash tank is further provided with a liquid level control device for controlling the on-off of the eighth pipeline.
According to one aspect of the invention, a ninth pipeline for inputting external desalted water is arranged at the upper part of the methyl acetate purification tower, a tenth pipeline for connecting with a catalytic decomposition tower is arranged at the top of the methyl acetate purification tower, and an eleventh pipeline for connecting with the methanol purification tower is arranged at the tower bottom of the methyl acetate purification tower;
and a twelfth pipeline connected with the methyl acetate purification tower is arranged at the top of the catalytic decomposition tower.
According to one aspect of the invention, the cooler is provided with a thirteenth pipeline connected with the ninth pipeline, and with a fourteenth pipeline connected with the liquid outlet of the centrifugal pump;
the cooler is also provided with a circulating water pipeline for connecting with external circulating water;
a liquid inlet of the centrifugal pump is provided with a fifteenth pipeline connected with the flash tank;
the first drain pipe is connected with the fifteenth pipeline through a sixteenth pipeline.
According to one aspect of the invention, a seventeenth pipeline for inputting external desalted water is arranged at the upper part of the methyl acetate rough separation tower, an eighteenth pipeline for connecting with the methyl acetate purification tower is arranged at the top of the methyl acetate rough separation tower, and a nineteenth pipeline for connecting with the eleventh pipeline is arranged at the bottom of the methyl acetate purification tower.
According to one aspect of the invention, the horizontal heat exchanger is provided with a twentieth pipeline for inputting alcoholysis waste liquid, a twenty-first pipeline for connecting the middle part of the methyl acetate coarse separation tower, and a twenty-second pipeline and a twenty-third pipeline connected with the first sewage discharge pipe;
the twenty-second pipeline and the twenty-third pipeline are respectively provided with a control valve for controlling the on-off of the twenty-second pipeline and the twenty-third pipeline;
a twenty-fourth pipeline is connected between the twentieth pipeline and the twenty-first pipeline; and a control valve for controlling the on-off of the twenty-fourth pipeline is arranged on the twenty-fourth pipeline.
According to one aspect of the invention, the methyl acetate rough separation tower is further provided with a twenty-fifth pipeline for connecting the seventeenth pipeline and the thirteenth pipeline, and a twenty-sixth pipeline for connecting the nineteenth pipeline, the fourteenth pipeline between the cooler and the centrifugal pump;
a twenty-seventh pipeline used for connecting the twentieth pipeline is further arranged on the twenty-sixth pipeline; and a control valve for controlling the on-off of the twenty-seventh pipeline is arranged on the twenty-seventh pipeline.
According to one aspect of the invention, the outlet of the centrifugal pump comprises: the cooling water is respectively connected with a ninth pipeline of the desalted water of the methyl acetate purification tower and a seventeenth pipeline of the desalted water of the methyl acetate rough separation tower through a thirteenth pipeline and a twenty-fifth pipeline; a twenty-sixth pipeline connected with the tower kettle of the methyl acetate rough separation tower; and the twenty-seventh pipeline is connected with the twentieth pipeline for feeding the methyl acetate rough separation tower and is used for cleaning the twentieth pipeline.
According to an aspect of the present invention, there is also provided a high temperature wastewater hot water self-coupling utilization method, applied to the high temperature wastewater hot water self-coupling utilization device according to any one of the above technical solutions, including the following steps:
step S1, introducing the high-temperature wastewater in the tower kettle of the methanol purification tower into the flash tank to form flash steam and flash tank drainage water, wherein the flash steam exchanges heat with the material in the catalytic decomposition tower in the first reboiler and is cooled to form hot water;
and S2, merging the hot water obtained in the step S1 with the drainage water of the flash tank, cooling by the cooler to obtain cooling water, and introducing the cooling water into the methyl acetate purification tower to replace desalted water for methyl acetate extraction and refining.
According to an aspect of the invention, further comprising:
and S3, the hot water obtained in the step S1 enters a horizontal heat exchanger to exchange heat with the feeding polyvinyl alcohol alcoholysis waste liquid of the methyl acetate rough separation tower, and the hot water obtained after cooling is merged with the drainage water of the flash tank.
According to an aspect of the invention, further comprising:
step S4, the hot water obtained in the step S3 is merged with the discharge water of the flash tank and then enters a centrifugal pump to be divided into three paths, the first path is sent to a cooler through a fourteenth pipeline for cooling and then is sent to a methyl acetate purification tower and a methyl acetate rough separation tower to replace desalted water for use; the second path replaces desalted water to clean a feeding pipeline of the methyl acetate rough separation tower through a twenty-seventh pipeline; and the third path is sent to a tower kettle of the methyl acetate rough separation tower through a twenty-sixth pipeline to replace desalted water for boiling and washing the tower plates.
According to the scheme of the invention, the effects of respectively recycling high-temperature wastewater steam and hot water, reducing steam consumption and demineralized water consumption, reducing sewage discharge and reducing sewage treatment pressure are achieved.
According to one scheme of the invention, by arranging the flash tank, high-temperature hot water (with the temperature of 120-. Through the arrangement, the steam can be saved by about 1.32 tons/ton of polyvinyl alcohol per year, and if the annual output of the polyvinyl alcohol is 1 ten thousand tons, the direct economic benefit is about 79 ten thousand yuan/year.
According to one scheme of the invention, the first drain pipe is arranged on the fifth pipeline, so that water discharged from the tower kettle of the methanol purification tower and the first reboiler can be discharged, the water with more solid impurities can be discharged after the system runs for a long time, and the long-time stable running of the whole system is ensured.
According to one scheme of the invention, the second reboiler and the sixth pipeline for conveying external steam are arranged, so that the heat energy supplement can be carried out through the second reboiler under the condition that the first reboiler cannot work or the heat supply is insufficient, and the stable operation of the invention is ensured.
According to one scheme of the invention, a plurality of blowdown pipes are arranged on the flash tank, so that blowdown operation of the flash tank can be carried out under the condition that one blowdown pipe is blocked, and the long-time continuous operation of the flash tank is ensured. In addition, one of the sewage pipes is controlled by the liquid level control device, so that the dynamic control of the sewage discharge of the flash tank can be realized, and the improvement of the sewage discharge efficiency and the stable operation of the system are facilitated.
According to the scheme of the invention, the first reboiler, the flash tank, the centrifugal pump and the cooler are additionally arranged, hot water (the temperature is 120-140 ℃) in the tower kettle of the methanol purification tower is cooled in two stages through the first reboiler (the temperature of the hot water after heat exchange is 90-100 ℃) and the cooler (the temperature of the water after heat exchange is 30-40 ℃), the hot water is sent to the methyl acetate purification tower to be used as extraction water for circulation, and the hot water in the tower kettle of the methanol purification tower can be used as a heat source of the tower kettle of the catalytic decomposition tower through the newly arranged first reboiler, so that the steam consumption of the catalytic decomposition tower is reduced, the consumption of desalted water is saved, the utilization rate of water resources is improved, and the discharge capacity is reduced. Through the arrangement, the method can save steam by about 1.32 tons/ton polyvinyl alcohol, save the use amount of desalted water by about 3.64 tons/ton polyvinyl alcohol, reduce the sewage discharge by about 3.64 tons/ton polyvinyl alcohol, and generate direct economic benefit exceeding 104.5 ten thousand yuan/year if the annual output of the polyvinyl alcohol is 1 ten thousand tons.
According to a scheme of the invention, high-temperature hot water (with the temperature of 120-, one path is sent to a newly added cooler for cooling, and the cooled hot water is returned to the methyl acetate rough separation tower and the methyl acetate purification tower for recycling. Through the arrangement, the steam can be saved by about 1.6 tons/ton of polyvinyl alcohol, the consumption of desalted water can be saved by about 3.9 tons/ton of polyvinyl alcohol, the sewage discharge amount is reduced by about 3.9 tons/ton of polyvinyl alcohol, and if the annual output of the polyvinyl alcohol is 1 ten thousand tons, the direct economic benefit is about 114 ten thousand yuan/year.
According to one scheme of the invention, the three paths of hot water are subjected to the distribution strategy, so that the safe, stable and efficient operation of the system after technical improvement can be ensured, meanwhile, the comprehensive utilization of the hot water can be realized, and the aim of reducing the production cost is fulfilled.
According to one scheme of the invention, the high-temperature hot water can not only heat the feeding materials of the methyl acetate rough separation tower, but also be used for heat exchange of materials at the bottom of the catalytic decomposition tower through the first reboiler and the second reboiler. If other devices do not have a feeding heat exchange device, the water is directly sent to a newly-added cooler for cooling and then returned to each water using point for recycling.
According to one scheme of the invention, as the incoming material of the methyl acetate rough separation tower contains powder, tower plates, feeding pipelines and tower kettle pipelines of the methyl acetate rough separation tower are easy to block, demineralized water needs to be added to boil and wash once a month on average, hot water in a tower kettle of the methanol purification tower passes through a flash tank and then flows to a first reboiler and then to a horizontal heat exchanger for feeding the methyl acetate rough separation tower, and then to a newly-added cooler (namely a plate cooler), the hot water can exchange heat with the feeding of the methyl acetate rough separation tower, and meanwhile, the hot water can be used for boiling and washing the tower plates, the twentieth pipelines of the feeding pipelines and the tower kettle pipelines of the methyl acetate rough separation tower instead of the demineralized water, so that the use amount of the demineralized water is saved, the water resource utilization rate is improved, and the sewage discharge capacity is reduced. Through the arrangement, the nineteenth pipeline and the twentieth pipeline of the feeding pipeline for discharging the methyl acetate rough separation tower kettle are boiled and washed once per month on average, about 3 ten thousand tons of steam per year is saved each year, the consumption of the desalted water is saved by about 0.2 ten thousand tons per year, the discharge capacity is reduced by about 0.2 ten thousand tons per year, and the direct economic benefit is generated by about 3.2 ten thousand yuan per year.
According to the scheme of the invention, by adopting the tube-array horizontal heat exchanger, the equipment cleaning frequency is reduced, the use amount of desalted water is saved, and the discharge capacity is reduced; or a filter can be additionally arranged on the twentieth pipeline of the feeding pipeline of the methyl acetate rough separation tower to filter polyvinyl alcohol powder in the feeding of the methyl acetate rough separation tower, so that the normal operation of the whole device is ensured. In addition, the shell-and-tube horizontal heat exchanger can continuously feed and exchange heat for the methyl acetate rough separation tower, so that the steam usage amount of the methyl acetate rough separation tower is effectively reduced (before the shell-and-tube horizontal heat exchanger is adopted, the original plate heat exchanger is easy to block and runs discontinuously, the feeding temperature of the methyl acetate rough separation tower during the stop period is low, the steam consumption needs to be increased for feeding and heating, after the shell-and-tube horizontal heat exchanger is changed into the horizontal heat exchanger, the methyl acetate rough separation tower can be continuously fed and exchanged heat, and the steam amount of the methyl acetate rough separation tower is saved). Through the arrangement, the cleaning times of the tubular horizontal heat exchanger are effectively reduced, the continuous operation of the equipment can be ensured for more than three years, and the operation rate of the equipment is greatly improved.
Drawings
FIG. 1 is a view schematically showing a high temperature hot water comprehensive utilization apparatus according to an embodiment of the present invention;
FIG. 2 is a view schematically illustrating a high temperature hot water comprehensive utilization apparatus according to another embodiment of the present invention;
fig. 3 is a view schematically showing a high temperature hot water comprehensive utilization apparatus according to another embodiment of the present invention.
1 methanol purification tower, 2 catalytic decomposition tower, 3 flash tank, 4 first reboiler, 5 second reboiler, 6 methyl acetate purification tower, 7 cooler, 8 centrifugal pump, 9 methyl acetate rough separation tower, 10 horizontal heat exchanger, 11 first pipeline, 21 second pipeline, 31 third pipeline, 41 fourth pipeline, 42 fifth pipeline, 421 first blow-off pipe, 51 sixth pipeline, 32 seventh pipeline, 33 eighth pipeline, 34 liquid level control device, 61 ninth pipeline, 62 tenth pipeline, 63 eleventh pipeline, 22 twelfth pipeline, 71 thirteenth pipeline, 72 fourteenth pipeline, 73 circulating water pipeline, 81 fifteenth pipeline, 82 sixteenth pipeline, 91 seventeenth pipeline, 92 eighteenth pipeline, 93 nineteenth pipeline, 101 twentieth pipeline, 102 first pipeline, 103 twenty second pipeline, 104 twenty third pipeline, 105 twenty fourth pipeline, 94 twenty fifth pipeline, 95 twenty-sixth pipeline, 951 twenty-seventh pipeline
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
In describing embodiments of the present invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship that is based on the orientation or positional relationship shown in the associated drawings, which is for convenience and simplicity of description only, and does not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, the above-described terms should not be construed as limiting the present invention.
The present invention is described in detail below with reference to the drawings and the specific embodiments, which are not repeated 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 high-temperature hot water comprehensive utilization apparatus of a polyvinyl alcohol waste liquid recovery system according to the present invention includes: a methanol purification tower 1, a catalytic decomposition tower 2, a flash tank 3, a first reboiler 4 and a second reboiler 5 for the catalytic decomposition tower 2. In the present embodiment, the methanol purification column 1 and the first reboiler 4 are connected to the flash tank 3, and the catalytic decomposition column 2 is connected to the first reboiler 4 and the second reboiler 5. In the present embodiment, the first reboiler 4 and the second reboiler 5 are provided in parallel.
As shown in fig. 1, according to an embodiment of the present invention, the bottom of the methanol purification column 1 is connected to the inlet of the flash drum 3 by a first pipe 11. In the present embodiment, the bottom of the catalytic decomposition column 2 is connected to the lower inlets of the first reboiler 4 and the second reboiler 5 by the second line 21. The vapor outlet of the flash drum 3 is connected to the upper inlet of the first reboiler 4 by a third line 31. In the present embodiment, the upper outlets of the first reboiler 4 and the second reboiler 5 are connected to the lower portion of the catalytic decomposition column 2 by the fourth line 41. In the present embodiment, the lower outlet of the first reboiler 4 is connected to the first line 11 using the fifth line 42.
According to the invention, through arranging the flash tank 3, high-temperature hot water (with the temperature of 120 plus 140 ℃) in the tower kettle of the methanol purification tower 1 can enter the tank along the tangent line of the flash tank 3, secondary flash steam (with the temperature of 120 plus 130 ℃) can be generated in the tank after the tank is expanded according to the action of fluid two-phase flow and vortex separation, further the high-temperature hot water can be introduced into the low-pressure steam pipeline third pipeline 31 to enter the first reboiler 4 to heat the material (with the temperature of 90-100 ℃) introduced from the tower kettle of the catalytic decomposition tower 2 in the first reboiler 4 through the second pipeline 21, further the heat energy carried by the tower liquid of the methanol purification tower 1 can be recycled, meanwhile, the temperature of the tower kettle of the catalytic decomposition tower 2 can be kept to be 70-85 ℃ to ensure the normal operation of the catalytic decomposition tower 2, thus realizing the normal operation of the catalytic decomposition tower 2 under the premise of keeping the normal operation of the catalytic decomposition tower 2, the recycling of low-quality heat energy effectively improves the energy utilization rate of the invention, reduces the energy consumption of the invention and saves the production cost. Through the arrangement, the steam can be saved by about 1.32 tons/ton of polyvinyl alcohol per year, and if the annual output of the polyvinyl alcohol is 1 ten thousand tons, the direct economic benefit is about 79 ten thousand yuan/year.
As shown in fig. 1, the fifth pipe line 42 is provided with a first drain 421 for draining, according to an embodiment of the present invention.
According to the present invention, the first drain pipe 421 is provided on the fifth pipeline 42, so that water discharged from the bottom of the methanol purification tower 1 and the first reboiler 4 can be discharged, which is beneficial for discharging water with more solid impurities after the system is operated for a long time, and is beneficial for ensuring the long-time stable operation of the whole system.
As shown in fig. 1, according to one embodiment of the present invention, a sixth pipe 51 for connecting to an external steam source is connected to an upper inlet of the second reboiler 5.
By providing the second reboiler 5 and the sixth line 51 for transporting external steam according to the present invention, it is possible to ensure that the heat energy is supplemented by the second reboiler 5 in case the first reboiler 4 is not operated or the heat supply is insufficient, which is advantageous in ensuring the stable operation of the present invention.
As shown in fig. 1, according to one embodiment of the invention, a seventh line 32 and an eighth line 33 are connected to the blowdown of the flash tank 3. In this embodiment, the flash tank 3 is further provided with a liquid level control device 34 for controlling the switching of the eighth line 33.
According to the invention, by arranging a plurality of blowdown pipes on the flash tank 3, blowdown operation can be carried out on the flash tank 3 under the condition that one blowdown pipe is blocked, which is beneficial to ensuring long-time continuous operation of the flash tank. In addition, one of the sewage pipes is controlled by the liquid level control device, so that the dynamic control of the sewage discharge of the flash tank can be realized, and the improvement of the sewage discharge efficiency and the stable operation of the system are facilitated.
As shown in fig. 2, according to an embodiment of the present invention, the high-temperature hot water comprehensive utilization apparatus of the polyvinyl alcohol waste liquid recovery system further includes: methyl acetate purifying tower 6, cooler 7 and centrifugal pump 8. In this embodiment, the methyl acetate purification column 6 is connected to a cooler 7, and the cooler 7 is connected to the flash tank 3 by a centrifugal pump 8. In the present embodiment, the cooler 7 is a plate cooler.
As shown in fig. 2, according to an embodiment of the present invention, the methyl acetate purification column 6 is provided at an upper portion thereof with a ninth line 61 for inputting external desalted water, at a top thereof with a tenth line 62 for connecting to the catalytic decomposition column 2, and at a bottom thereof with an eleventh line 63 for connecting to the methanol purification column 1. In the present embodiment, a ninth line 61 is connected to the upper portion of the methyl acetate purification column 6, a tenth line 62 is connected to the middle portion of the catalytic decomposition column 2, and an eleventh line 63 is connected to the upper portion of the methanol purification column 1. In this embodiment, a twelfth pipeline 22 is provided at the top of the catalytic decomposition tower 2 to connect with the methyl acetate purification tower 6. The twelfth line 22 is connected to the upper portion of the methyl acetate purifying column 6.
As shown in fig. 2, according to one embodiment of the invention, the cooler 7 is provided with a thirteenth line 71 connected to the ninth line 61 and with a fourteenth line 72 connected to the outlet of the centrifugal pump 8. In the present embodiment, the cooler 7 is further provided with a circulating water line 73 for connecting with outside circulating water. In the present embodiment, the liquid inlet of the centrifugal pump 8 is provided with a fifteenth pipeline 81 connected with the flash tank 3.
As shown in fig. 2, the first drain 421 of the fifth pipe 42 is connected to the fifteenth pipe 81 through the sixteenth pipe 82 according to an embodiment of the present invention.
According to the present invention, the recycling of the contaminated water is achieved by providing the sixteenth pipe 82 to be connected with the fifteenth pipe 81.
As shown in fig. 1, according to one embodiment of the present invention, a plurality of centrifugal pumps 8 are arranged in parallel. In the present embodiment, two centrifugal pumps 8 are provided in parallel.
According to the invention, the fifteenth pipeline 81 and the fourteenth pipeline 72 are more unobstructed by arranging a plurality of centrifugal pumps 8 in parallel, so that the defect that the pipeline is blocked due to the blockage of a single centrifugal pump 8 is overcome, and the stable work of the whole pipeline is ensured. In addition, by arranging a plurality of centrifugal pumps 8 in parallel, the flow rate between the fifteenth pipeline 81 and the fourteenth pipeline 72 can be effectively controlled by changing the working number of the incorporated centrifugal pumps, and the flexibility of use of the present invention is improved.
According to the invention, through newly adding the first reboiler 4, the flash tank 3, the centrifugal pump 8 and the plate cooler 7, hot water (with the temperature of 120-. Through the arrangement, the steam can be saved by about 1.32 tons/ton of polyvinyl alcohol, the consumption of desalted water can be saved by about 3.64 tons/ton of polyvinyl alcohol, the sewage discharge can be reduced by about 3.64 tons/ton of polyvinyl alcohol, and if the annual output of the polyvinyl alcohol is 1 ten thousand tons, the direct economic benefit is generated by about 104.5 ten thousand yuan/year.
As shown in fig. 3, according to an embodiment of the present invention, the high-temperature hot water comprehensive utilization apparatus of the polyvinyl alcohol waste liquid recovery system further includes: a methyl acetate crude separation tower 9 and a horizontal heat exchanger 10. In the present embodiment, the methyl acetate crude separation tower 9 is connected to the methanol purification tower 1, the methyl acetate purification tower 6, the cooler 7, and the horizontal heat exchanger 10, respectively. In the present embodiment, the horizontal heat exchanger 10 is connected to the flash tank 3, the methyl acetate crude separation column 9, and the fourteenth line 72 between the cooler 7 and the centrifugal pump 8.
As shown in fig. 3, according to an embodiment of the present invention, the upper portion of the methyl acetate rough separation column 9 is provided with a seventeenth pipeline 91 for inputting external desalted water, the top portion thereof is provided with an eighteenth pipeline 92 for connecting with the methyl acetate purification column 6, and the bottom thereof is provided with a nineteenth pipeline 93 for connecting with the eleventh pipeline 63. In the present embodiment, the eighteenth line 92 is connected to the middle portion of the methyl acetate purification column 6.
As shown in fig. 3, according to an embodiment of the present invention, the horizontal heat exchanger 10 is provided with a twentieth pipeline 101 for inputting the alcoholysis waste liquid, a twenty-first pipeline 102 for connecting to the middle part of the methyl acetate rough separation tower 9, and a twenty-second pipeline 103 and a twenty-third pipeline 104 for connecting to the first blowdown pipe 421 on the fifth pipeline 42. In the present embodiment, the twenty-second pipeline 103 and the twenty-third pipeline 104 are provided with control valves for controlling on and off thereof, respectively.
As shown in fig. 3, a twenty-fourth pipe 105 is connected between the twentieth pipe 101 and the twenty-first pipe 102 according to an embodiment of the present invention. In the present embodiment, the twenty-fourth line 105 is provided with a control valve for controlling the on/off state thereof. By the arrangement, incoming material conveying of the methyl acetate rough separation tower 9 can be ensured when the horizontal heat exchanger 10 is overhauled.
As shown in fig. 3, according to one embodiment of the present invention, the methyl acetate rough separation column 9 is further provided with a twenty-fifth pipe 94 for connecting the seventeenth pipe 91 and the thirteenth pipe 71, and with a twenty-sixth pipe 95 for connecting the nineteenth pipe 93 and the fourteenth pipe 72. In the present embodiment, a twenty-seventh pipe 951 for connecting the twentieth pipe 101 is further provided to the twenty-sixth pipe 95. In this embodiment, the twenty-seventh pipe 951 is provided with a control valve for controlling on/off of the pipe.
According to the invention, high-temperature hot water (with the temperature of 120-, one path of the hot water is sent to a newly added cooler 7 for cooling, and the cooled hot water is returned to the methyl acetate rough separation tower 9 and the methyl acetate purification tower 6 for recycling. Through the arrangement, the steam can be saved by about 1.6 tons/ton of polyvinyl alcohol, the consumption of desalted water can be saved by about 3.9 tons/ton of polyvinyl alcohol, the sewage discharge amount is reduced by about 3.9 tons/ton of polyvinyl alcohol, and if the annual output of the polyvinyl alcohol is 1 ten thousand tons, the direct economic benefit is about 114 ten thousand yuan/year.
To further explain the scheme, the working flow of the scheme is further explained by combining the attached drawings.
FIG. 1:
the flow in the figure is applicable to the recovery process, and the flow introduces: the incoming material of the methanol purification tower 1 is methanol solution (temperature is 70-90 ℃) from a methyl acetate crude separation tower 9 and a methyl acetate purification tower 6, refined methanol is distilled from the top of the methanol purification tower 1 and is sent to a tank area, high-temperature wastewater (temperature is 120-. The coming material of the catalytic decomposition tower 2 is methyl acetate distilled from a methyl acetate purification tower 6 (the temperature is 56-65 ℃), the distillate distilled from the top of the catalytic decomposition tower 2 (methyl acetate and methanol, the temperature is 50-68 ℃) is basically total reflux, the methyl acetate is sent to the methyl acetate purification tower 6 for reprocessing, a second reboiler 5 is a direct steam heat exchange reboiler of the original catalytic decomposition tower 2, a sixth pipeline 51 is a direct steam pipeline, the bottom liquid of the catalytic decomposition tower 2 (acetic acid, methanol and methyl acetate, the temperature is 70-85 ℃) enters a first reboiler 4 and the second reboiler 5 through a second pipeline 21 for heat exchange respectively, the heated steam returns to the tower from the tops of the first reboiler 4 and the second reboiler 5 through a fourth pipeline 41 respectively, and the bottom liquid of the catalytic decomposition tower 2 is the coming material of a crude acetic acid separation tower (the temperature is 70-85 ℃). The bottom of the flash tank 3 is provided with a seventh pipeline 32 and an eighth pipeline 33 which are respectively provided with drain valves, the liquid level of the flash tank is remotely controlled by a regulating valve on the pipeline of the eighth pipeline 33, the seventh pipeline 32 is used as a spare of the eighth pipeline 33, and the liquid level control device 34 is a flash tank liquid level meter.
FIG. 2:
in the figure 2, the device of a methyl acetate purification tower 6, a cooler 7 and a centrifugal pump 8 are additionally arranged on the basis of the figure 1. The coming material of the methyl acetate purification tower 6 is crude methyl acetate distilled from a methyl acetate crude separation tower 9 (the temperature is 55-60 ℃). The incoming material of the methanol purification tower 1 is methanol solution (with the temperature of 70-90 ℃) from a methyl acetate crude separation tower 9 and a methyl acetate purification tower 6, refined methanol is distilled from the top of the methanol purification tower 1 and is sent to a tank area, high-temperature waste water (with the temperature of 120-. Methyl acetate distilled from the methyl acetate purification tower 6 (the temperature is 56-65 ℃) feeds the catalytic decomposition tower 2 through a tenth pipeline 62, the distillate distilled from the top of the catalytic decomposition tower 2 (methyl acetate and methanol, the temperature is 50-68 ℃) is basically total reflux, sending the waste liquid to a methyl acetate purification tower 6 through a pipeline 22 for reprocessing, wherein a second reboiler 5 is a direct steam heat exchange reboiler of an original catalytic decomposition tower 2, a sixth pipeline 51 is a direct steam pipeline (the temperature is 220-250 ℃), the bottom liquid (acetic acid, methanol and methyl acetate, the temperature is 70-85 ℃) of the catalytic decomposition tower 2 enters a first reboiler 4 and the second reboiler 5 through a second pipeline 21 for heat exchange respectively, the heated steam returns to the tower from the tops of the first reboiler 4 and the second reboiler 5 through a fourth pipeline 41 respectively, and the bottom liquid of the catalytic decomposition tower 2 is the incoming material (the temperature is 70-85 ℃) of an acetic acid rough separation tower. The seventh pipeline 32 and the eighth pipeline 33 at the bottom of the flash tank 3 are provided with drain valves, the liquid level of the flash tank 3 is remotely controlled by a regulating valve on the pipeline of the eighth pipeline 33, the seventh pipeline 32 is used as a spare of the eighth pipeline 33, and 34 is a flash tank liquid level meter. A sixteenth pipeline 82 is additionally arranged on the first drain pipe 421, a fifteenth pipeline 81 is additionally arranged at the bottom of the flash tank 3, both the sixteenth pipeline 82 and the fifteenth pipeline 81 are used as materials for the centrifugal pump 8, the outlet of the centrifugal pump 8 is sent to the cooler 7 through a fourteenth pipeline 72 for cooling, the cooler 7 is cooled by circulating water through a circulating water pipeline 73, and the cooled water (with the temperature of 30-40 ℃) is connected with a ninth pipeline 61 of desalted water of the methyl orthoacetate purification tower 6 through a thirteenth pipeline 71, so that the usage amount of the desalted water of the methyl acetate purification tower 6 is reduced.
FIG. 3:
in the figure 3, a methyl acetate rough separation tower 9 and a horizontal heat exchanger 10 are additionally arranged on the basis of the figure 2, the methyl acetate rough separation tower 9 mainly has the function of rough separation of methyl acetate, crude methyl acetate (with the temperature of 55-60 ℃) distilled from the top of the methyl acetate rough separation tower 9 is fed into a methyl acetate purification tower 6 through an eighteenth pipeline 92, and a methanol solution (with the temperature of 65-75 ℃) discharged from the kettle of the methyl acetate rough separation tower 9 is sent to the methanol purification tower 1 through a nineteenth pipeline 93 for continuous purification. The horizontal heat exchanger 10 is a feeding horizontal heat exchanger of the methyl acetate rough separation tower 9, supplied materials are alcoholysis waste liquid of a tank area, main components of the alcoholysis waste liquid are methyl acetate and methanol, the alcoholysis waste liquid are sent to the horizontal heat exchanger 10 through a twentieth pipeline 101, the alcoholysis waste liquid are used as supplied materials (with the temperature of 50-65 ℃) of the methyl acetate rough separation tower 9 after heat exchange, and a seventeenth pipeline 91 is a desalted water feeding pipeline of the methyl acetate rough separation tower 9.
The incoming material of the methanol purification tower 1 is methanol solution (temperature is 70-90 ℃) from a methyl acetate crude separation tower 9 and a methyl acetate purification tower 6, refined methanol is distilled from the top of the methanol purification tower 1 and is sent to a tank area, high-temperature wastewater (temperature is 120-. Methyl acetate distilled from the methyl acetate purification tower 6 (the temperature is 56-65 ℃) feeds the catalytic decomposition tower 2 through a tenth pipeline 62, the distillate distilled from the top of the catalytic decomposition tower 2 (the temperature is 50-68 ℃) is basically total reflux, the waste liquid is sent to a methyl acetate purification tower 6 for reprocessing through a twelfth pipeline 22, a second reboiler 5 is a direct steam heat exchange reboiler of the original catalytic decomposition tower 2, a sixth pipeline 51 is a direct steam pipeline (the temperature is 220-250 ℃), the kettle liquid (acetic acid, methanol and methyl acetate, the temperature is 70-85 ℃) of the catalytic decomposition tower 2 respectively enters a first reboiler 4 and the second reboiler 5 through a second pipeline 21 for heat exchange, the heated steam respectively returns to the tower from the tops of the first reboiler 4 and the second reboiler 5 through a fourth pipeline 41, and the kettle liquid (the temperature is 70-85 ℃) of the catalytic decomposition tower 2 is the incoming material of an acetic acid rough separation tower. The bottom of the flash tank 3 is provided with a line 32 and a line 33 and with a drain valve, the flash tank liquid level is remotely controlled by a regulating valve on the line 33, the seventh line 32 serves as a backup for the eighth line 33, and 34 is a flash tank level gauge. The sixteenth pipeline 82 is arranged on the first drain pipe 421, the fifteenth pipeline 81 is arranged at the bottom of the flash tank 3, and the sixteenth pipeline 82 and the fifteenth pipeline 81 are used as incoming materials of the centrifugal pump 8.
The outlet of the centrifugal pump 8 is divided into three paths, firstly, the centrifugal pump is sent to the cooler 7 through a fourteenth pipeline 72 for cooling, the cooler 7 is cooled by circulating water (with the temperature of 20-35 ℃) through a circulating water pipeline 73, the cooled water (with the temperature of 30-40 ℃) is respectively connected with a ninth pipeline 61 of desalted water (with the temperature of 10-25 ℃) of the methyl acetate purification tower 6 through a thirteenth pipeline 71 and a twenty-fifth pipeline 94, and a seventeenth pipeline 91 of desalted water (with the temperature of 10-25 ℃) of the methyl acetate rough separation tower 9 is connected, so that the usage amount of the desalted water of the methyl acetate rough separation tower 9 and the methyl acetate purification tower 6 is reduced. Secondly, the twenty-seventh pipeline 951 is used as cleaning water of the twentieth pipeline 101 for feeding materials to the daily methyl acetate crude separation tower 9 to replace demineralized water, and because polyvinyl alcohol powder is easy to dissolve at high temperature, the effect of cleaning the pipeline by hot water (at the temperature of 90-100 ℃) is better than that of the demineralized water (at the temperature of 10-25 ℃), the pipeline is cleaned more cleanly and thoroughly, and the cleaning frequency is reduced from one time of one quarter to one time of the original cleaning. Thirdly, the water is sent to the tower kettle of the methyl acetate crude separation tower 9 through a twenty-sixth pipeline 95 to replace desalted water for boiling and washing the tower plate, hot water (with the temperature of 90-100 ℃) has certain heat, and the temperature is far higher than the temperature of the desalted water, so that the heat is saved by using the hot water to replace the desalted water for boiling and washing the tower plate, the usage amount of the desalted water is greatly reduced, the sewage discharge is reduced, and the usage amount of direct steam is saved.
The right side of the horizontal heat exchanger 10 is provided with heating medium hot water (with the temperature of 90-100 ℃), a hot water shell pass is formed, a twenty-second pipeline 103 of a hot water inlet pipeline (with the temperature of 90-100 ℃) and a twenty-third pipeline 104 of an outlet pipeline (with the temperature of 60-80 ℃) are respectively connected with the fifth pipeline 42 and the sixteenth pipeline 82, and a first sewage discharge pipe 421 of a bypass is arranged; the left side of the horizontal heat exchanger 10 is provided with cold medium alcoholysis waste liquid (with the temperature of 30-40 ℃), the alcoholysis waste liquid is conveyed through a pipe pass, a twentieth pipeline 101 at the inlet (with the temperature of 30-40 ℃), a twenty-first pipeline 102 at the outlet (with the temperature of 50-65 ℃), and a twenty-fourth pipeline 105 with a bypass is arranged before the twentieth pipeline 101 and the twenty-first pipeline 102, wherein if the horizontal heat exchanger 10 is stopped or overhauled, a first drain pipe 421 and the twenty-fourth pipeline 105 with the bypass are started. Because the alcoholysis waste liquid contains polyvinyl alcohol powder, the alcoholysis waste liquid is easy to clean after equipment is blocked, a shell pass is designed to be taken by hot water, and a tube pass is designed to be taken by the alcoholysis waste liquid.
According to the invention, through adding a flash tank 3, a reboiler 4 (namely a first reboiler), a cooler 7, a horizontal heat exchanger 10 and a centrifugal pump 8, high-temperature hot water (with the temperature of 120-, the cooled hot water (the temperature is 30-40 ℃) returns to the methyl acetate crude separation tower 9 and the methyl acetate purification tower 6 for recycling. The hot water is distributed in three ways, so that the hot water recycling amount of the methyl acetate purification tower 6 is about 15-30m when each tower normally operates 3 The hot water recycling amount of the methyl acetate crude separation tower 9 is about 1-5m (accounting for 75 percent of the total amount of the hot water) 3 H (15% of the total hot water content) and flash tank emptying valve connectionContinuously draining water for about 2-4m 3 H (10% of the total hot water). The coming material of the methyl acetate coarse separation tower 9 is powder, which easily causes the blockage of tower plates, feeding pipelines and tower kettle pipelines of the methyl acetate coarse separation tower 9, and the desalted water needs to be added for boiling and washing once per month on average, and when the methyl acetate coarse separation tower 9 needs to be stopped for boiling and washing, the hot water return amount of the methyl acetate purification tower 6 can be reduced to about 5-10m 3 The hot water recycling amount of the methyl acetate crude separation tower 9 is increased to about 20-25m (accounting for 40 percent of the total amount of the hot water) 3 The recycled hot water can replace demineralized water and can be boiled and washed on the tower plate of the methyl acetate rough separation tower 9 through the twenty-fifth pipeline 94, the feeding pipeline twentieth pipeline 101 is introduced through the twenty-seventh pipeline 951, and the recycled hot water enters the tower kettle pipeline of the methyl acetate rough separation tower 9 through the twenty-sixth pipeline 95 to the nineteenth pipeline 93 for use, so that the use amount of the demineralized water is saved, the water resource utilization rate is improved, and the sewage discharge amount is reduced. Through the arrangement, the nineteenth pipeline 93 and the twentieth pipeline 101 of the feeding pipeline for discharging from the tower bottom of the methyl acetate rough separation tower 9 are boiled and washed once per month on average, so that about 3 ten thousand tons of steam are saved each year, about 0.2 ten thousand tons of desalted water are saved each year, the discharge capacity is reduced by about 0.2 ten thousand tons each year, and the direct economic benefit is generated by about 3.2 ten thousand yuan each year.
According to the invention, the high-temperature hot water can not only heat the material fed into the methyl acetate rough separation tower 9, but also be used for heat exchange of the material in the tower bottom of the catalytic decomposition tower 3 through the first reboiler 4. If other devices do not have a charging heat exchange device, the water is directly sent to the newly-added cooler 7 for cooling and then returned to each water using point for recycling.
According to the invention, by adopting the tube-array horizontal heat exchanger 10, the equipment cleaning frequency is reduced, the consumption of demineralized water is saved, and the discharge capacity is reduced; or a filter can be additionally arranged on the twentieth pipeline 101 of the feeding pipeline of the methyl acetate rough separation tower 9 to filter polyvinyl alcohol powder in the feeding of the methyl acetate rough separation tower 9, so that the normal operation of the whole device is ensured. In addition, the shell-and-tube horizontal heat exchanger 10 can continuously feed and exchange heat for the methyl acetate rough separation tower 9, and the steam usage amount of the methyl acetate rough separation tower 9 is effectively reduced. Through the arrangement, the cleaning times of the tubular horizontal heat exchanger are effectively reduced, the continuous operation of equipment can be ensured for more than three years, and the operation rate of the equipment is greatly improved.
The foregoing is merely exemplary of particular aspects of the present invention and devices and structures not specifically described herein are understood to be those of ordinary skill in the art and are intended to be implemented in such conventional ways.
The above description is only one embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (14)
1. The utility model provides an alcoholysis waste liquid retrieves high temperature waste water hot water self coupling and utilizes device which characterized in that includes: the system comprises a methanol purification tower (1), a catalytic decomposition tower (2), a flash tank (3), a first reboiler (4), a methyl acetate purification tower (6), a cooler (7) and a centrifugal pump (8);
the tower kettle of the methanol purification tower (1) is sequentially connected with the flash tank (3), the first reboiler (4) and the catalytic decomposition tower (2) through pipelines; the catalytic decomposition tower (2) is connected with the methanol purification tower (1) through the methyl acetate purification tower (6);
the flash tank (3) is sequentially connected with the centrifugal pump (8), the cooler (7) and the methyl acetate purifying tower (6) through pipelines;
after high-temperature wastewater in the tower kettle of the methanol purification tower (1) enters the flash tank (3), flash steam and flash tank drainage are formed, and the flash steam exchanges heat with the material in the catalytic decomposition tower (2) in the first reboiler (4) and is cooled to form hot water; the hot water is converged with the drainage water of the flash tank, and the cooled water is obtained after being cooled by the cooler (7) and then enters the methyl acetate purification tower (6).
2. The self-coupling utilization device of hot water in high-temperature wastewater recycled by alcoholysis waste liquid of claim 1, further comprising a methyl acetate crude separation tower (9) and a horizontal heat exchanger (10);
the methyl acetate rough separation tower (9) is respectively connected with the methanol purification tower (1), the methyl acetate purification tower (6), the cooler (7) and the horizontal heat exchanger (10);
the horizontal heat exchanger (10) is respectively connected with the flash tank (3), the methyl acetate rough separation tower (9) and the centrifugal pump (8), and the horizontal heat exchanger (10) is a shell-and-tube horizontal heat exchanger;
and the polyvinyl alcohol alcoholysis waste liquid enters the horizontal heat exchanger (10) to exchange heat with the hot water and then enters the methyl acetate rough separation tower (9), and the hot water is cooled and then is merged with the drainage water of the flash tank.
3. The self-coupling utilization device for hot water in recycling high-temperature waste water from alcoholysis waste liquid of claim 1, wherein a tower kettle of the methanol purification tower (1) is connected with an inlet of the flash tank (3) through a first pipeline (11);
the steam outlet of the flash tank (3) is connected with the upper inlet of the first reboiler (4) by a third pipeline (31);
the upper outlet of the first reboiler (4) is connected with the lower part of the catalytic decomposition tower (2) by a fourth pipeline (41);
the lower outlet of the first reboiler (4) is connected to the first line (11) by a fifth line (42); and a first sewage discharge pipe (421) for discharging sewage is arranged on the fifth pipeline (42).
4. The alcoholysis waste liquid recovery high-temperature wastewater hot water self-coupling utilization device according to claim 1, further comprising a second reboiler (5) connected in parallel with the first reboiler (4), wherein the bottom of the catalytic decomposition tower (2) is connected with the lower inlets of the first reboiler (4) and the second reboiler (5) by a second pipeline (21); the upper inlet of the second reboiler (5) is connected with a sixth pipeline (51) for connecting with an external steam source; the upper outlet of the second reboiler (5) is connected with the lower part of the catalytic decomposition tower (2) by a fourth pipeline (41).
5. The alcoholysis waste liquid recovery high-temperature waste water and hot water self-coupling utilization device according to claim 3, wherein a drain outlet of the flash tank (3) is connected with a seventh pipeline (32) and an eighth pipeline (33), and the flash tank (3) is further provided with a liquid level control device (34) for controlling the on-off of the eighth pipeline (33).
6. The self-coupling utilization device for hot water in high-temperature wastewater recycled by alcoholysis waste liquid of claim 5, wherein a ninth pipeline (61) for inputting external desalted water is arranged at the upper part of the methyl acetate purification tower (6), a tenth pipeline (62) for connecting with the catalytic decomposition tower (2) is arranged at the top of the methyl acetate purification tower, and an eleventh pipeline (63) connected with the methanol purification tower (1) is arranged at the bottom of the methyl acetate purification tower;
the top of the catalytic decomposition tower (2) is provided with a twelfth pipeline (22) connected with the methyl acetate purification tower (6).
7. The self-coupling device for recycling hot water from high-temperature waste water recovered from alcoholysis waste liquid as claimed in claim 6, wherein the cooler (7) is provided with a thirteenth pipeline (71) connected to the ninth pipeline (61) and with a fourteenth pipeline (72) connected to the liquid outlet of the centrifugal pump (8);
the cooler (7) is also provided with a circulating water pipeline (73) for connecting with external circulating water;
a fifteenth pipeline (81) is arranged at a liquid inlet of the centrifugal pump (8) and is connected with the flash tank (3);
the first drain pipe (421) is connected to the fifteenth pipe (81) via a sixteenth pipe (82).
8. The self-coupling utilization device for hot water in alcoholysis waste liquid recovery high-temperature waste water according to claim 7, wherein the upper part of the methyl acetate rough separation tower (9) is provided with a seventeenth pipeline (91) for inputting external desalted water, the top part of the methyl acetate rough separation tower is provided with an eighteenth pipeline (92) for connecting with the methyl acetate purification tower (6), and the bottom of the methyl acetate rough separation tower is provided with a nineteenth pipeline (93) for connecting with the eleventh pipeline (63).
9. The self-coupling utilization device for hot water in recycling high-temperature waste water from alcoholysis waste liquid according to claim 8, wherein the horizontal heat exchanger (10) is provided with a twentieth pipeline (101) for inputting alcoholysis waste liquid, a twenty-first pipeline (102) for connecting with the middle part of the methyl acetate crude separation tower (9), and a twenty-second pipeline (103) and a twenty-third pipeline (104) connected with the first drain pipe (421);
control valves for controlling the on-off of the twenty-second pipeline (103) and the twenty-third pipeline (104) are respectively arranged on the twenty-second pipeline and the twenty-third pipeline;
a twenty-fourth pipeline (105) is connected between the twentieth pipeline (101) and the twenty-first pipeline (102); and a control valve for controlling the on-off of the twenty-fourth pipeline (105) is arranged on the twenty-fourth pipeline.
10. The alcoholysis waste liquid recovery high-temperature waste water hot water self-coupling utilization device according to claim 9, wherein the methyl acetate rough separation tower (9) is further provided with a twenty-fifth pipeline (94) for connecting the seventeenth pipeline (91) and the thirteenth pipeline (71), and a twenty-sixth pipeline (95) for connecting the nineteenth pipeline (93), the fourteenth pipeline (72) between the cooler (7) and the centrifugal pump (8);
a twenty-seventh pipeline (951) used for connecting the twentieth pipeline (101) is further arranged on the twenty-sixth pipeline (95); and a control valve for controlling the on-off of the twenty-seventh pipeline (951) is arranged on the twenty-seventh pipeline.
11. The alcoholysis waste liquid recovery high temperature waste water hot water self-coupling utilization device according to claim 2, wherein the outlet of the centrifugal pump (8) comprises: a fourteenth pipeline (72) connected with the cooler (7), wherein the cooling water is respectively connected with a ninth pipeline (61) of the desalted water of the methyl acetate purifying tower (6) and a seventeenth pipeline (91) of the desalted water of the methyl acetate rough separation tower (9) through a thirteenth pipeline (71) and a twenty-fifth pipeline (94); a twenty-sixth pipeline (95) connected with the tower kettle of the methyl acetate rough separation tower (9); a twenty-seventh pipeline (951) connected to the twentieth pipeline (101) for feeding the methyl acetate crude separation column (9) for purging the twentieth pipeline (101).
12. A high-temperature waste water and hot water self-coupling utilization method applied to the high-temperature waste water and hot water self-coupling utilization device as claimed in any one of claims 1 to 11, characterized by comprising the following steps of:
step S1, introducing the high-temperature wastewater in the tower bottom of the methanol purification tower (1) into the flash tank (3) to form flash steam and flash tank drainage water, wherein the flash steam exchanges heat with the material in the catalytic decomposition tower (2) in the first reboiler (4) and is cooled to form hot water;
and step S2, the hot water obtained in the step S1 is converged with the flash tank drainage water, the temperature of the hot water is reduced by the cooler (7) to obtain cooling water, and the cooling water is introduced into the methyl acetate purification tower (6) to replace demineralized water for methyl acetate extraction and refining.
13. The polyvinyl alcohol high-temperature wastewater self-coupling utilization method according to claim 12, further comprising:
and S3, the hot water obtained in the step S1 enters a horizontal heat exchanger (10) to exchange heat with the feeding polyvinyl alcohol alcoholysis waste liquid of the methyl acetate crude separation tower (9), and the hot water obtained after temperature reduction is merged with the drainage water of the flash tank.
14. The polyvinyl alcohol high-temperature wastewater self-coupling utilization method according to claim 13, further comprising:
step S4, the hot water obtained in the step S3 is merged with the flash tank discharge water and then enters a centrifugal pump (8) to be divided into three paths, the first path is sent to a cooler (7) through a fourteenth pipeline (72) to be cooled and then is sent to a methyl acetate purification tower (6) and a methyl acetate rough separation tower (9) to replace desalted water for use; the second path is used for replacing desalted water to clean a feeding pipeline of a methyl acetate rough separation tower (9) through a twenty-seventh pipeline (951); the third path is sent to the kettle of the methyl acetate rough separation tower (9) through a twenty-sixth pipeline (95) to replace desalted water for boiling and washing the tower plates.
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| CN202011595789.1A CN112619194B (en) | 2020-12-29 | 2020-12-29 | High-temperature hot water comprehensive utilization device of polyvinyl alcohol waste liquid recovery system |
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| CN109721484A (en) * | 2019-01-21 | 2019-05-07 | 中国石化长城能源化工（宁夏）有限公司 | A kind of system and device and preparation method thereof using polyvinyl alcohol by-product methyl acetate production acetic acid |
| CN110981835A (en) * | 2019-12-16 | 2020-04-10 | 江苏怡达化学股份有限公司 | Methanol recovery method in propylene oxide production |
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2020
- 2020-12-29 CN CN202011595789.1A patent/CN112619194B/en active Active
- 2020-12-29 CN CN202210934639.1A patent/CN115089990A/en active Pending
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| CN112619194A (en) | 2021-04-09 |
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