Distillation system using multi stage stripper capable of integrated operation and steam consumption reduction

The present invention relates to a distillation system using multi-stage stripper, the distillation system being configured to separate mixed material into high volatile components and low volatile components based on difference of boiling point, the system comprising: a stripper module including a plurality of strippers, and configured to receive the feedstock material, evaporate and discharge the high volatile component as overhead vapor and to separate the low volatile component as un-distilled; a condense-evaporator configured to condense the overhead vapor and to evaporate water; and a mechanical vapor recompression module that compresses water vapor evaporated in the condense-evaporator by multi-stages.

CLAIM OF PRIORITY

This application is a continuation application off of International Patent Application No. PCT/KR2014/003655 filed on Apr. 25, 2014, which claims Priority from Korean Application No. 10-2014-0044341 filed Apr. 14, 2014, the contents of which are both incorporated herein by reference.

FIELD OF THE EMBODIMENTS

The present disclosure relates to a distillation system using a multi-stage stripper capable of integrated operation and reduction of steam consumption, and more particularly, to a distillation system using a multi-stage stripper in order to separate materials from a mixed compound based on difference of boiling point, wherein overhead vapor being discharged from a stripper module is condensed to evaporate water and then the evaporated water vapor is compressed by multi-stages and supplied to at least two strippers, thereby increasing heat recovery rate of the overhead vapor of the stripper and reducing the time and cost being spent in a distillation process.

BACKGROUND OF THE EMBODIMENTS

Distillation systems are for evaporating and separating mixed materials existing in a feedstock material based on difference of boiling point. In the upper portion of a distillation system, a material with a low boiling point (high volatile component) is evaporated in the form of overhead vapor, while in the lower portion of the distillation system, a material with a high boiling point (low volatile component) is separated in a non-distilled form. Here, the high volatile component and the low volatile component may each be a singular component, or a mixture of two or more components.

Such a distillation system essentially includes an evaporative separator configured to separate materials according to difference of boiling point. Examples of such an evaporative separator include distillation column, rectification column, stripping column, stripping vessel and stripper, etc.

In the case of extracting a high volatile component to be prepared as a subject product, the rectification column is used, but in the case of extracting a low volatile component to be prepared as a subject product, the stripping column or stripping vessel (or stripper) is used. Stripping columns are usually used to extract a low volatile component having a low viscosity, and stripping vessels (or strippers) are usually used to extract a low volatile component having a high viscosity.

FIG. 1is a view schematically illustrating a conventional distillation system having a stripping vessel. Referring toFIG. 1, the conventional distillation system10having a stripping vessel consists of a the stripping vessel110where a feedstock material is separated into a low volatile component and a high volatile component, and a condenser120where overhead vapor of the high volatile component is condensed. The stripping vessel110strips and refines the high volatile component, and recovers the refined high volatile component as raw material, while drying the low volatile component having a high viscosity to obtain a final product.

When steam is supplied from a steam supplier160to the stripping vessel110, the steam directly contacts the mixed material of a high viscosity in the lower portion of the stripping vessel110and transfers heat thereto. By this heat, the high volatile component of the mixed material is evaporated and is discharged as overhead vapor together with water vapor, and the high boiling point material of the mixed material is discharged externally together with condensate water of the steam.

However, the distillation system ofFIG. 1separates the feedstock material into a low volatile component and a high volatile component in a singular stripping vessel110, and thus has a problem that the feedstock material cannot be separated with precision, thereby reducing the purity or recovery rate of product.

In order to solve the aforementioned problem of the distillation system illustrated inFIG. 1, a distillation system having two or more stripping vessels was proposed.

FIG. 2is a view schematically illustrating a conventional distillation system provided with two or more stripping vessels. Referring toFIG. 2, the distillation system20having two stripping vessels includes a first stripping vessel111to which a feedstock material is supplied, a second stripping vessel112to which material not stripped in the first stripping vessel111is supplied, a condense-evaporator120where overhead vapor discharged from the first stripping vessel111and water exchange heat, a condenser130where overhead vapor not condensed in the condense-evaporator120is condensed for the last time, and two compression modules141,142.

In the distillation system20having the two stripping vessels, first of all, a feedstock material is supplied to the first stripping vessel111. When steam is supplied from the steal supplier160according to the temperature required in the first stripping vessel111, a high volatile component of the feedstock material is discharged as overhead vapor, while a low volatile component is separated in a non-distilled form in a lower portion of the first stripping vessel111. Here, in the first stripping vessel111, only the high volatile components having a boiling point below a certain temperature are discharged as overhead vapor, whereas the materials having a boiling point of or above the certain temperature are not discharged as overhead vapor. For this reason or the like, not all the feedstock is separated into high volatile components and low volatile components, and thus the non-separated material is supplied to the second stripping vessel112to be further separated.

The overhead vapor discharged from the first stripping vessel111exchanges heat with water in the condense-evaporator120to generate saturated water vapor, and then passes the first compression module141, and is re-supplied to the first stripping vessel111. In the first stripping vessel111, this re-supplied water vapor is used to separate the feedstock material.

Meanwhile, the overhead vapor not condensed in the condense-evaporator120is supplied to the condenser130, and is condensed for the last time. The condensed solution generated in the condenser130is separated from water based on specific gravity, and is supplied to a distillation column180. A re-boiler190supplies steam to the distillation column, and steam condensate water generated in the re-boiler190is expanded under low pressure (flashed), and then compressed in the second compression module142, and then supplied to the second stripping vessel112. This steam condensate water supplied to the second stripper vessel112exchanges heat with the feedstock material discharged from the first stripping vessel111, and is used for the final stripping.

That is, the condensed solution that has been condensed and separated in the condenser must be supplied to the distillation column180to be distilled, and the high temperature steam condensate water must be expanded and evaporated in the re-boiler190, and then compressed in the second compression module142and supplied to the second stripping vessel112. Generally, it takes several hours for a multi-stage stripping process to stabilize after the overhead vapor discharged from the first stripping vessel111is condensed and separated and supplied to the distillation column. In order to initially drive the first stripping vessel111, steam is supplied from the steam supplier160according to the temperature required in the first stripping vessel111, and even when the water vapor generated by the heat exchange between the overhead vapor discharged from the first stripping vessel111and water passes the first compression module141and is supplied to the first stripping vessel111again and used, the steam is not sufficient to operate the first stripping vessel111, and thus steam must keep being supplied from the steam supplier160.

For this reason, due to the excessive amount of steam that needs to be supplied from outside until the second stripping vessel112operates to supply the overhead vapor of the second stripping vessel112to the first stripping vessel111, it costs a lot of money. Further, since the temperature condition required in the second stripping vessel111is higher than the temperature required in the first stripping vessel111, there occurs a problem where the first compression module141and the second compression module142must be driven separately.

Various systems are known in the art. However, their structure and means of operation are substantially different from the present disclosure. At least one embodiment of this invention is presented in the drawings below and will be described in more detail herein.

SUMMARY OF THE EMBODIMENTS

In general, the present invention succeeds in conferring the following, and others not mentioned, benefits and objectives.

Problem to be Solved

Therefore, a purpose of the present disclosure is to solve the aforementioned problems of prior art, that is, to provide a distillation system using a multi-stage stripper capable of integrated operation and reduction of steam consumption, and more particularly, to a distillation system using a multi-stage stripper in order to separate materials from a mixed compound based on difference of boiling point, where overhead vapor being discharged from a stripper module is condensed and water is evaporated, and then the evaporated water vapor is compressed by multi-stages and supplied to at least two strippers, thereby increasing heat recovery rate of the overhead vapor of the stripper and reducing time and cost being spent in a distillation process.

Technical Solutions

The aforementioned purpose of the present disclosure is achieved by a distillation system using multi-stage stripper capable of integrated operation and reduction of steam consumption, the distillation system configured to separate mixed material existing in a feedstock material into high volatile components and low volatile components based on difference of boiling point, the system comprising: a stripper module including a plurality of strippers, and configured to receive the feedstock material, evaporate and discharge the high volatile component as overhead vapor and configured to separate the low volatile component as un-distilled in a lower portion of the stripper, wherein gas-liquid equilibrium pressure and temperature of the high volatile component being evaporated in each of the strippers are different from each other; a condense-evaporator configured to condense the overhead vapor that passed through the stripper module and to evaporate water supplied from a source of water supply by heat exchanging the overhead vapor with the water; and a mechanical vapor recompression module (MVR) that compresses water vapor evaporated in the condense-evaporator by multi-stages, wherein the water vapor compressed in the mechanical vapor recompression module is supplied to at least two strippers.

Here, it is preferable that a portion of the water vapor compressed in the mechanical vapor recompression module is supplied to the stripper that evaporates the high volatile component with the highest temperature.

Here, it is preferable that the stripper module includes a first stripper configured to receive the feedstock material, evaporate the high volatile component, and discharge the evaporated high volatile component as the overhead vapor, and configured to separate the low volatile component as un-distilled in the lower portion of the stripper; and a second stripper configured to operate at a higher temperature than the first stripper, receive material that is not evaporated in the first stripper, strip the high volatile component, discharge the stripped high volatile component as the overhead vapor, and configured to separate the low volatile component as un-distilled in the lower portion of the stripper, wherein a portion of the water vapor compressed in the mechanical vapor recompression module is preferentially supplied to the second stripper, and the rest of the water vapor is supplied to the first stripper.

Here, it is preferable that the temperature and pressure of the water vapor passing through the mechanical vapor recompression module is the temperature and pressure required to separate the feedstock material in the first stripper, and that the system further includes a thermal vapor recompression (TVR) module that induces a portion of the water vapor passing the mechanical vapor recompression module to be supplied towards the second stripper, and that increases the temperature and pressure of the water vapor being supplied to the second stripper to the temperature and pressure required to separate the feedstock material in the second stripper.

Here, it is preferable that the overhead vapor of the second stripper is supplied to the first stripper so as to be used as a heat source necessary for separating the feedstock material in the first stripper.

Here, it is preferable that the system further includes a steam supplier that supplies steam to the first stripper and the second stripper; a first valve that is configured to be opened or closed so as to control whether or not to supply the steam to the first stripper; and a second valve that is configured to be opened or closed so as to control whether or not to supply the steam to the second stripper.

Here, it is preferable that the system further includes a third valve that is configured to be opened or closed, and configured to induce a portion of the steam being supplied from the steam supplier towards the thermal vapor recompression module.

Here, it is preferable that the mechanical vapor recompression (MVR) module includes a first module that is configured as a plurality of mechanical vapor recompression apparatuses; a second module that is configured as a plurality of mechanical vapor recompression apparatuses, and that further compresses the water vapor that passed through the first module; and a laminator that reduces the velocity of the compressed water vapor that passed through the first module and supplies the compressed water vapor to the second module.

Here, it is preferable that the system further includes a condenser that receives the overhead vapor not condensed in the evaporator and condenses the received overhead vapor; and a distillation column that receives solution condensed in the condenser.

Here, it is preferable that the system further includes a re-boiler that supplies the steam to the distillation column, wherein steam condensate water of the re-boiler is evaporated and is supplied to the laminator.

Here, it is preferable that the laminator adjusts the temperature of the compressed water vapor that passed through the first module and the temperature of the vapor evaporated from the steam condensate water supplied form the re-boiler to be identical to each other.

Here, it is preferable that a flow rate controller is installed on an inlet end of the first module.

Advantageous Effects

According to the present disclosure, there is provided distillation system using a multi-stage stripper capable of integrated operation and reduction of steam consumption, where water is evaporated by the overhead vapor being discharged from the stripper module stripper, and then the evaporated water vapor is compressed by multi-stages and supplied to at least two strippers, thereby increasing heat recovery rate of the overhead vapor of the stripper and reducing time and cost being spent in a distillation process.

Further, the present disclosure provides a distillation system using a multi-stage stripper capable of integrated operation and reduction of steam consumption regardless of the type of the subject material to be stripped since water and overhead vapor exchange heat in a condense-evaporator, and thus may be applied regardless of the components forming the high volatile component or difference in saturated vapor pressure.

Further, as the water vapor evaporated in the condense-evaporator is compressed by multi-stages and supplied to at least two strippers, the second stripper and the first stripper may be driven almost at the same time.

Further, as the saturated water vapor being discharged from the second module is supplied to the first stripper and the second stripper, the first module and the second module may be controlled at the same time.

Further, as a laminator is installed between the first module and the second module, the saturated water vapor may be introduced into the second module at an even vapor density, thereby preventing the second module from being damaged.

Further, as the laminator is installed between the first module and the second module, the temperature of the vapor being supplied from the re-boiler and the temperature of the saturated water vapor being discharged from the first module may be adjusted to be the same, and then supplied to the second module.

Further, as a thermal vapor recompression module is installed, the saturated water vapor being discharged from the second module may be easily supplied towards the second stripper.

Further, as the thermal vapor recompression module is installed, the temperature and pressure of the saturated water vapor being discharged from the second module may be easily set to the temperature and pressure required in the stripping process in the second stripper.

Further, after the condensate water from the condenser is introduced into the distillation column, steam need not be supplied from the steam supplier to the first stripper, thereby effectively reducing the cost being spent in the distillation process.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a distillation system using a multi-stage stripper capable of integrated operation and reduction of steam consumption will be explained in detail with reference to the drawings attached.

The present invention relates to a distillation system using a multi-stage stripping vessel, that is, a multi-stage stripper. The distillation system using a multi-stage stripper capable of integrated operation and reduction of steam consumption according to an embodiment of the present invention relates to a distillation system using a multi-stage stripper capable of integrated operation and reduction of steam consumption, where water is evaporated using overhead vapor being discharged from the stripper module, and then the evaporated water vapor is compressed by multi-stages and supplied to at least two strippers, thereby increasing heat recovery rate of the overhead vapor of the stripper module and reducing the cost being spent in a distillation process.

FIG. 3is a view schematically illustrating a distillation system using a multi-stage stripper capable of integration operation and reduction of steam consumption according to an embodiment of the present disclosure. Referring toFIG. 3, the distillation system100using a multi-stage stripper capable of integrated operation and reduction of steam consumption includes a stripper module110where a feedstock material is supplied, a condense-evaporator120where the overhead vapor discharged from the stripper module110and water exchange heat, a condenser130where the overhead vapor not condensed in the condense-evaporator120is supplied and condensed, a mechanical vapor recompression module140where saturated water vapor generated in the condense-evaporator120is supplied and compressed, a thermal vapor recompression module150that increases the temperature and pressure of a portion of the saturated water vapor that passed the mechanical vapor recompression module140, valves170that control whether or not to supply steam from the steam supplier160, a distillation column180and a re-boiler190.

The stripper module110refers to the stripping vessel module for stripping a monomer of a low boiling point from the feedstock material to obtain a polymer of a high boiling point having a high viscosity, and the stripper module110includes a first stripper111and a second stripper112. Here, the feedstock material may be, for example, a mixed material that may be produced after a polymerization reaction of synthetic rubber.

The first stripper111is an apparatus configured to be supplied with the feedstock material in which mixed material or the like exists, and to separate a high volatile component and a low volatile component. To the first stripper111, steam is supplied from the steam supplier160through a first valve171that is controlled according to conditions such as temperature or the like required in the first stripper111. Further, overhead vapor is supplied from the second stripper112, and saturated water vapor discharged from the second module142is supplied. The aforementioned steam and the saturated water vapor are the same material. The steam supplied from the steam supplier160directly contacts the low volatile component in a lower portion of the first stripper111and transfers heat, and by this heat, the high volatile component of the mixed material is evaporated, and is discharged as overhead vapor together with water vapor.

Meanwhile, the first stripper111does not evaporate all the high volatile components existing in the feedstock material. Each of the high volatile component and the low volatile component may be a mixed material of two or more components, in which case, the temperature of the steam required to evaporate all the high volatile components may be high, thereby incurring a lot of cost. Therefore, the first stripper111is configured to evaporate only the high volatile components having a boiling point below a certain temperature.

The second stripper112is an apparatus that receives the high volatile components not separated in the first stripper111and the low volatile components, and separates the components. In the first stripper111, only the high volatile components having a boiling point of below a certain temperature are evaporated, and the high volatile components having a boiling point of or above the certain temperature are evaporated in the second stripper112, and thus the second stripper112is driven at a higher temperature than the first stripper111.

The second stripper112is configured to receive steam from the steam supplier160and the thermal vapor recompression module150. Specifically, the steam is supplied from the steam supplier160through the second valve172that is controlled according to conditions such as temperature or the like required in the second stripper112. Further, from the thermal vapor recompression module150, the steam that passed through the third valve173controlled according to the conditions such as temperature or the like required in the second stripper112and through the second module142is supplied.

Meanwhile, the second stripper112operates at a higher temperature than the first stripper111. Therefore, the overhead vapor being discharged from the second stripper112is supplied to the first stripper111, and this overhead vapor is used as a source of heat for separating the feedstock material in the first stripper111.

The condense-evaporator120is a configuration for condensing overhead vapor of a single or two or more different components which has different saturated vapor pressures and which is supplied from the first stripper111, and for transferring a maximum quantity of heat to water, thereby generating water vapor having the quantity of heat corresponding to the transferred quantity of heat. Specifically, to the condense-evaporator120, water is supplied from a separate source of water supply, and overhead vapor of an amount required in the condense-evaporator120is condensed to transfer the quantity of heat to the water such that the saturated water vapor may be compressed in the mechanical vapor recompression module140up to the temperature and pressure required in the first stripper111. The rest of the overhead vapor that is not condensed is supplied to the condenser130, and the water that received heat from the overhead vapor becomes saturated water vapor and is supplied to the mechanical vapor recompression module140.

In the present embodiment, the water vapor generated by heat exchange with overhead vapor is compressed and used as a heat medium, and thus it is unnecessary to compress the overhead vapor, and thus the present embodiment may be applied in distilling high volatile components of two or more components having different saturated vapor pressures, without limitation. Further, since the condensed latent heat of the overhead vapor may be removed by evaporated latent heat of water, there is an advantage that a relatively small amount of water can be used compared to the removal by sensible heat of circulating cooling water.

The condenser130is a configuration for condensing overhead vapor not condensed in the condense-evaporator120. The overhead vapor not condensed in the condense-evaporator120is supplied to the condenser130to be condensed for the last time. The condensed solution generated in the condenser130is separated based on specific gravity, and then supplied to the distillation column180.

The mechanical vapor recompression module140is a configuration for compressing the saturated water vapor generated in the condense-evaporator120to the temperature and pressure required in the first stripper111, and the mechanical vapor recompression module140includes a first module141, a second module142, a laminator143and a flow rate controller144.

The first module141is a configuration for compressing the saturated water vapor generated in the condense-evaporator120. The first module141is provided as a plurality of mechanical vapor recompression apparatuses.

Examples of the mechanical vapor recompression apparatus that may be used herein include a high velocity compressor and a low velocity blast centrifugal compressor, etc. A low velocity blast centrifugal compressor is a compressor of low velocity below 10000 rpm. It is of low cost and drives at a low velocity, and thus provides an advantage of stable operation without causing any damage to the compressor. However, since the low velocity blast centrifugal compressor is a compressor of low velocity below 10000 rpm, preferably 4000 to 7000 rpm, it provides a low compression ratio compared to a high velocity multi-stage turbo compressor, and therefore, the blast centrifugal compressor is provided in plural numbers in order to compensate for the low compression ratio. That is, the saturated water vapor saturated in the condense-evaporator120is compressed by multi-stages in the plurality of blast centrifugal compressors according to a certain compression ratio. Although it was explained hereinabove that in the present embodiment the mechanical vapor recompression apparatus is a low velocity blast centrifugal compressor, as long as the saturated water vapor can be compressed such that the conditions such as the temperature and pressure of the saturated water vapor generated in the condense-evaporator120correspond to the temperature and pressure required in the first stripping vessel111, the mechanical vapor recompression apparatus is not limited thereto.

In an inlet end of the first module141, a flow rate controller144may be installed. At an initial stage of driving the first stripper111, there is not so much overhead vapor, and thus, the amount of saturated water vapor being generated in the condense-evaporator120may be small. If this amount is lower than the flow rate required in the mechanical vapor recompression apparatus, noise and vibration may occur, and the mechanical vapor recompression apparatus may be damaged. Here, by installing the flow rate controller144, the aforementioned problem can be prevented. Examples of the flow rate controller144that may be used include an inlet guide vane (IGV) and an inverter motor controller, etc.

The second module142is a configuration for compressing the saturated water vapor compressed in the first module141for the last time such that it may have the temperature and pressure required in the first stripper111. The second module142is provided as a plurality of mechanical vapor recompression apparatuses. Meanwhile, the mechanical vapor recompression apparatus of the second module142may be provided as a low velocity blast centrifugal compressor just as in the first module141.

The laminator143is a configuration installed between the first module141and the second module142to reduce the velocity by which the saturated water vapor is discharged from the first module141and to control the temperature.

The first module141is configured as a plurality of blast centrifugal compressors to compress the saturated water vapor generated in the condense-evaporator120in multi-stages. The saturated water vapor that passed through the plurality of blast centrifugal compressors have a very high velocity pressure, and thus a powerful vortex will be formed by a rotary motion of an impeller or the like. This makes the distribution of vapor density being introduced into the second module142uneven, and thus, due to the high velocity pressure, an overstress may occur on a portion of an impeller cross-section of the blast centrifugal compressor of the second module142, causing concerns for vibration and damage. However, by installing the laminator143between the first module141and the second module142, the velocity of the saturated water vapor being discharged from the first module141may be reduced, and most of the high velocity pressure of the saturated water vapor at 50 to 90 m/s may be converted into static pressure, enabling the vapor to be introduced into the second module142slowly at an even vapor density without causing a vortex phenomenon.

Further, the laminator143adjusts the temperature of the saturated water vapor being discharged from the first module141. Not only the saturated water vapor being discharged from the first module141but also the vapor expanded and evaporated from the steam condensate water generated in the re-boiler190is supplied to the laminator143. After achieving an equilibrium of temperature between the saturated water vapor and the vapor from the re-boiler, the laminator143supplies the saturated water vapor and the vapor to the second module142. That is, after adjusting the temperature of the vapor expanded and evaporated from the steam condensate water generated in the re-boiler190and the temperature of the saturated water vapor being discharged from the first module141to be identical to each other, the vapor from the re-boiler and the saturated water vapor are supplied to the second module142to be compressed to the temperature and pressure required in the first stripper111.

The thermal vapor recompression module150is a configuration for compressing the saturated water vapor that passed through the mechanical vapor recompression module140to the temperature and pressure required in the second stripper112. A portion of the saturated water vapor that passed through the mechanical vapor recompression module140is supplied to the second stripper112, and is used to separate the feedstock material, and the rest of the saturated water vapor is supplied to the first stripper111, and is used to separate the feedstock material. Here, the water vapor that passed through the mechanical vapor recompression module140is preferentially compressed to the temperature and pressure required in the first stripper111. Since the second stripper112is driven at a higher temperature than the first stripper111, the water vapor that passed the mechanical vapor recompression module140needs to be compressed additionally. The saturated water vapor is compressed as it passes through the thermal vapor recompression module150to have the temperature and pressure required in the second stripper112, and the amount of steam necessary in the second stripper112is automatically supplied by the third valve173installed on the thermal mechanical recompression module150.

In the present embodiment, the saturated water vapor that passed through the second module142is preferentially introduced towards the second stripper112. Therefore, the thermal vapor recompression module150absorbs the saturated water vapor that passed through the second module142and introduces the saturated water vapor into the second stripper112. Further, when the second stripper112and the second module142are spaced far apart from each other, it is difficult for the saturated water vapor that passed through the second module142to be introduced into the second stripper112. In this case, the thermal vapor recompression module150absorbs the saturated water vapor that passed through the second module142and preferentially induces introduction of the saturated water vapor towards the second stripper112.

The steam supplier160is a configuration for supplying steam to the stripper module110, that is, to the first stripper111and second stripper112and the thermal vapor recompression module150. When the steam supplied from the steam supplier160is supplied to the first stripper111, the steam directly contacts the high volatile component in the lower portion and transfers heat, and by this heat, the high volatile component of the mixed material is evaporated and is discharged as overhead vapor together with the water vapor.

The valve170is a configuration for controlling whether or not to supply steam to the stripper module110, and the valve170includes the first valve171, the second valve172and the third valve173.

The first valve171is a configuration for controlling whether or not to supply the steam being supplied from the steam supplier160to the first stripper171. The first valve171controls the amount of steam to be supplied to the first stripper111according to the temperature condition required to separate the feedstock material in the first stripper111. The first valve171is opened at the initial stage of driving the distillation system100, enabling steam to be supplied inside the first stripper111. Until the vapor evaporated from the steam condensate water of the re-boiler141is supplied to the laminator143, the vapor which passed through the first module141, was compressed in the second module142, and then was re-compressed in the thermal vapor recompression is preferentially supplied to the second stripper112. The amount of vapor lacking the third valve173of the thermal vapor recompression module150is supplied from the second valve172.

The second valve172is a configuration for controlling whether or not to supply the steam being supplied from the steam supplier160to the second stripper112. Unlike the first valve171, the second valve172is not opened at the initial driving stage of the apparatus, but is opened when the amount of steam being supplied from the third valve173after the third valve173was opened as will be explained hereinafter is insufficient for gas-liquid pressure equilibrium with the first stripper111. In that case, the opened second valve172supplements steam, so that the feedstock material can be separated in the second stripper112.

The third valve173is a configuration for controlling whether or not to supply the steam being supplied from the steam supplier160to the second stripper112. However, unlike the second valve172, the third valve173does not allow the steam to be supplied directly to the second stripper112, but to be supplied to the thermal vapor recompression module150. That is, the third valve173limits the amount of steam being supplied to thermal vapor recompression module150according to the temperature condition required in the second stripper112, and then the steam is supplied to the second stripper112after being compressed in the thermal vapor recompression module150.

The distillation column180is a configuration for receiving the condensate water generated in the condenser130and then for rectifying the condensate water received. The re-boiler190is a configuration for supplying steam into the distillation column180. The condensate water of the steam generated in the re-boiler190is expanded and evaporated, and then supplied to the laminator143. As aforementioned, the temperature of the vapor being evaporated and supplied to the laminator143and the temperature of the vapor being supplied from the first module141to the laminator143are different from each other, but they are adjusted to the same temperature in the laminator143, and are then supplied to the second module.

Hereinafter, an operation of the distillation system using a multi-stage stripper capable of integration operation and reduction of steam consumption according to an embodiment of the present disclosure will be explained.

Operations before and after the condensate water generated in the condenser130is supplied to the distillation column180will be explained separately.

1. Operation Before the Condensate Water Generated in the Condenser is Supplied to the Distillation Column

FIG. 4is a view schematically illustrating an operation before the condensate water generated in the condenser is supplied to the distillation column in the distillation system using a multi-stage stripper capable of integration operation and reduction of steam consumption.

First of all, feedstock material is supplied from the supplier to the first stripper111.

The first valve171that is controlled according to conditions such as temperature or the like required in the first stripper111is opened, so that steam is supplied from the steam supplier160to the first stripper111. The steam directly contacts the low volatile component in the lower portion of the first stripper111and transfers heat thereto. By this heat, the high volatile component, of the feedstock material, having a boiling point of below a certain temperature is evaporated and is discharged as overhead vapor together with water vapor, while low volatile components that are not distilled are supplied to the second stripper112.

The overhead vapor discharged from the first stripper111is introduced into the condense-evaporator120. A portion of the overhead vapor is condensed in the condense-evaporator120and transfers quantity of heat to water being provided from a separate source of water supply. The water that received heat from the overhead vapor turns into saturated water vapor, and this saturated water vapor is supplied to the mechanical vapor recompression module140, while the overhead vapor that is not condensed is supplied to the condenser130.

The saturated water vapor generated in the condense-evaporator120is supplied to the first module141. Here, there may be a flow rate controller144installed to control the flow rate of the saturated water vapor being supplied to the first module141.

The saturated water vapor is compressed by multi-stages as it passes through the first module141, and then is supplied to the laminator143. As the saturated water vapor passes the first module141, its velocity pressure increases, and a vortex may be formed by rotation of an impeller or the like. This may lead to an uneven distributing of vapor density being introduced into the second module142, causing damage to the second module142. On the other hand, the laminator143of the present disclosure reduces the velocity pressure of the saturated water vapor, prevents the vortex from being formed, and preferably makes the saturated water vapor to make a straight line motion, and makes the saturated water vapor to be introduced at an even vapor density into the second module142. Meanwhile, as the velocity pressure is reduced as aforementioned, the static pressure will increase, but the saturated water vapor will be introduced at an even vapor density into the second module142compared to when the velocity pressure is high, thereby preventing the apparatus from being damaged. The saturated water vapor that passed through the laminator143and that is introduced into the second module142is further compressed by multi-stages to meet the temperature and pressure condition for separating the feedstock material in the first stripper111.

A portion of the saturated water vapor discharged from the second module142is preferentially absorbed by the thermal vapor recompression module150. That is, the portion of the saturated water vapor discharged from the second module142is supplied to the thermal vapor recompression module150while the rest of the saturated water vapor is supplied to the first stripper111. The saturated water vapor introduced into the thermal vapor recompression module150is further compressed to the temperature and pressure required in the second stripper112, and thereafter, this further compressed saturated water vapor separates the feedstock material in the second stripper112. Here, at the initial stage of driving the distillation system100, the amount of overhead vapor generated in the first stripper111is not sufficient, and a portion of the water vapor is supplied to the second stripper112by the thermal vapor recompression module150. But since that amount is insufficient at the initial driving stage, water vapor may be supplemented by controlling the second valve172.

Meanwhile, the overhead vapor generated by the separating of feedstock material by means of the steam being supplied to the second stripper112is supplied to the first stripper111. Since the temperature required in the second stripper112is higher than the first stripper111, the overhead vapor of the second stripper112may be used as a heat source for the first stripper111. When the supplying of steam by the first valve171at the first stripper111is controlled in a satisfactory manner, the second valve172supplying the steam to the second stripper112is closed, and by controlling the third valve173, the first stripper111and the second stripper112enter a stable operation state. Of course in this process, the condensed solution generated and separated in the condenser is supplied to the distillation column180, and the vapor expanded and evaporated in the re-boiler190is introduced into the laminator143, enabling the first module141and the second module142to enter the stable operation state.

2. Operation after the Condensate Water Generated in the Condenser is Supplied to the Distillation Column

FIG. 5is a view schematically illustrating an operation after the condensate generated in the condenser is supplied to the distillation column in the distillation system using a multi-stage stripper capable of integration operation and reduction of steam consumption.

As aforementioned, the overhead vapor not condensed in the condense-evaporator120is supplied to the condenser130, and then is condensed for the last time. The condensed solution generated and separated in the condenser130is supplied to the distillation column180, and then is rectified. Here, for the rectifying in the distillation column180, steam is supplied from the re-boiler190.

Steam condensate water is generated in the re-boiler190, and the generated steam condensate water is evaporated and then is supplied to the laminator143. That is, after the condensate water is supplied to the distillation column180, the saturated water vapor discharged from the first module141and the vapor evaporated from the steam condensate water discharged from the re-boiler190are supplied to the laminator143.

The laminator143adjusts the temperature of the saturated water vapor and the temperature of the vapor from the re-boiler to be the same and reduces the velocity pressure, and enables the saturated water vapor and the vapor from the re-boiler to be supplied to the second module142. That is, compared to the operation before the condensed solution is supplied to the distillation column180, an increased amount of saturated water vapor is supplied to the second module142and is compressed.

The saturated water vapor discharged from the second module142is absorbed and compressed by the thermal vapor recompression module150, and then supplied to the second stripper112. The thermal vapor recompression module150is designed such that the vapor generated from the steam condensate water discharged from the re-boiler190is added and thus, the amount of steam being supplied by the third valve173is sufficient to cover the amount to be supplied to the second stripper112.

Then, the overhead vapor generated by the stripping reaction in the seconds tripper112is supplied to the first stripper111. Since sufficient amount of steam is supplied to the second stripper112, sufficient amount of overhead vapor may be supplied to the first stripper111. Further, since there is a large amount of saturated water vapor being discharged from the second module142, a large amount of saturated water vapor is supplied to the first stripper111. Therefore, there is sufficient amount of steam to cover the required amount in the first stripper111. Accordingly, whether or not to shut off supply of new steam by closing the first valve171depends on the composition of the overhead vapor of the multi-stage stripper, but generally, it is expected that just a small amount of steam needs to be supplemented.

Then, the overhead vapor generated in the first stripper111is supplied to the condense-evaporator120again, and the aforementioned circulation process is repeated.

Therefore, the present disclosure provides a distillation system using a multi-stage stripper, where water is evaporated using the overhead vapor being discharged from a stripper module, and then the evaporated water vapor is compressed by multi-stages and then supplied to at least two strippers, thereby increasing heat recovery rate of the upper steam of the stripper and reducing the cost spent in a distillation process.

In the drawings and specification, there have been disclosed typical embodiments of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

INDUSTRIAL APPLICABILITY

The present disclosure provides a distillation system using a multi-stage stripper capable of integrated operation and reduction of steam consumption, the distillation system configured to separate mixed material based on difference of boiling point, where water is evaporated using the overhead vapor being discharged from a stripper module, and then the evaporated water vapor is compressed by multi-stages and then supplied to at least two strippers, thereby increasing heat recovery rate of the upper steam of the stripper and reducing the cost spent in a distillation process.