KR102097608B1 - Meg regeneration apparatus - Google Patents

Abstract

MEG reproducing apparatus is disclosed. MEG regeneration device according to an embodiment of the present invention is supplied with a rich MEG precipitated with low solubility salt from the pre-treatment unit and distillation column to generate lean MEG by evaporating water from the rich MEG using the difference between the water and the MEG, A reboiler that receives the product at the bottom of the distillation column and heats it to return to the distillation column, and a reflux condenser provided at the top of the distillation column to condense gas components including water evaporated from the distillation column, and to separate the condensed gas components into gas liquid A re-concentration unit including a reflux drum returning a portion of the fluid to the distillation column; A regeneration unit for removing solid solution salt from lean MEG; And vacuum means provided at the front end of the reflux condenser or the rear end of the reflux drum to allow the re-concentration unit to operate under reduced pressure.

Description

MEG regeneration device {MEG REGENERATION APPARATUS}

The present invention relates to a MEG playback device.

In the production of natural gas in the deep sea, hydrate may be produced in the pipeline due to the conditions of low temperature and high pressure. When natural gas is supplied through a pipeline, hydrate may damage or corrode the inside of the pipeline, and in severe cases, a pipeline or gas field clogging may occur. Therefore, MEG (Mono Ethylene Glycol) is injected to suppress the formation of hydrate.

MEG has a strong hydrophilic property to absorb moisture, and after injection to suppress the formation of hydrate, MEG absorbs moisture in the gas and is recovered from the top of offshore plants. The recovered MEG solution (hereinafter also referred to as “rich MEG”) contains impurities such as water, high soluble salts, and low soluble salts. The rich MEG can be extracted with high concentration of MEG by removing water and salts through the MEG regeneration process.

The MEG regeneration process is a full stream concept in which the MEG solution is vaporized at a time to remove salts, and some of the low solubility salts are first removed through pretreatment, then water is removed, and then solid solution salts are removed. There is a slip stream concept.

Specifically, the entire treatment method consists of removing hydrocarbons from the rich MEG, removing solid solution salts and low solution salts using flash, and then removing water using a difference in the breaking point.

Since the entire treatment method removes all salts by vaporization, there is no problem caused by salts, but a large amount of energy is consumed because the entire MEG solution must be vaporized to remove the salts.

Some of the treatment methods to compensate for these shortcomings are to remove low solubility salts and hydrocarbons from rich MEG, and then evaporate water in a distillation column to produce lean MEG, and then remove solid solution salts from lean MEG. Is made of Here, the product at the bottom of the distillation column is supplied, heated in a reboiler, and returned to the distillation column to evaporate water from the rich MEG to produce lean MEG.

Some of these treatment methods classify the salts to be removed into high and low solubility salts. Low solubility salts are mainly divalent salts such as Ca2 +, Mg2 +, and Ba2 +, and are poorly soluble in water. Solubility decreases with increasing temperature, and precipitation occurs. On the other hand, solid solution salts are mainly monovalent salts such as Na + and K +, which are well soluble in water and solubility increases with increasing temperature.

On the other hand, although some of the above-described treatment methods have higher energy efficiency than the entire treatment methods, scale deposition of salt may occur in the device. For example, if the low-solubility salt is not sufficiently removed through the pre-treatment process, efficiency may be reduced due to salt deposition in the process of generating lean MEG by evaporating water from the rich MEG. That is, the temperature at the bottom of the distillation column is higher than the temperature at the time of the low solubility salt removal process, and since the water is constantly being removed from the distillation column, the concentration of the salt contained in the water increases. Accordingly, salt deposition may occur at the bottom of the distillation column and the reboiler, and when the salt deposition becomes severe, serious problems such as stopping operation may occur.

Please refer to Korean Patent Publication No. 10-2017-0059675 (published on May 31, 2017) as a technology related to the above.

Korean Patent Publication No. 10-2017-0059675 (released on May 31, 2017)

An embodiment of the present invention is to provide a MEG regeneration device that effectively prevents scale deposition of salt to improve the efficiency of operation.

According to an aspect of the present invention, a distillation column for generating lean MEG by evaporating water from the rich MEG using the difference between the water and the MEG by receiving the rich MEG from which the low solubility salt precipitated from the pre-treatment unit, and the distillation column A reboiler which receives the lower product and heats it to return to the distillation column, a reflux condenser provided on the top of the distillation column and condensing gas components including water evaporated from the distillation column, and the condensed gas component A re-concentration unit including a reflux drum for separating and returning some of the liquid fluid to the distillation column; A regeneration unit for removing the solid solution salt from the lean MEG; And a vacuum means provided at a front end of the reflux condenser or a rear end of the reflux drum to allow the re-concentration unit to operate under reduced pressure.

The vacuum means is provided at the front end of the reflux condenser, and the driving fluid flowing toward the first inlet is ejected at a high speed toward the outlet to inhale gas components at the top of the distillation column through the second inlet, and the distillation column and the li It may include an ejector that allows the boiler to operate under reduced pressure in a vacuum.

The vacuum means includes an ejector connected to a gaseous discharge line for discharging gas components of the reflux drum, and the ejector is provided at a rear end of the reflux drum, and ejects the driving fluid flowing toward the first inlet at a high speed toward the outlet. The gas component of the reflux drum may be sucked through the second inlet, and the reflux drum, the reflux condenser, the distillation column and the reboiler at the front end may be operated under reduced pressure in a vacuum.

The regeneration unit is supplied by a flash separator that receives lean MEG from which water is removed from the re-concentration unit to remove solid solution salt from the lean MEG, a regeneration condenser that condenses gas components on the top of the flash separator, and the regeneration condenser. It includes a regeneration drum for separating the condensed product gas-liquid, but is connected to the suction line between the regeneration drum and the front end of the ejector of the gas phase discharge line, so that the regeneration unit is operated under reduced pressure.

The vacuum means includes a first vacuum pump connected to a gaseous discharge line for discharging gaseous components of the reflux drum, and the first vacuum pump sucks gas components of the reflux drum through the gaseous discharge line. The reflux drum, the reflux condenser, the distillation column and the reboiler can be operated under reduced pressure in a vacuum.

MEG playback apparatus according to an embodiment of the present invention can improve the efficiency of the overall operation.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will become apparent to those skilled in the art from the description of the claims.

1 shows a MEG playback apparatus according to an embodiment of the present invention.
2 shows a MEG playback apparatus according to another embodiment of the present invention.
Figure 3 shows a MEG playback apparatus according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments introduced below are provided as examples in order to sufficiently convey the spirit of the present invention to those skilled in the art to which the present invention pertains. The present invention is not limited to the embodiments described below and may be embodied in other forms. In order to clearly describe the present invention, parts not related to the description are omitted in the drawings, and in the drawings, the width, length, and thickness of components may be exaggerated for convenience. Throughout the specification, the same reference numbers indicate the same components.

Referring to FIG. 1, the MEG regeneration device 1000 according to an embodiment of the present invention removes impurities from the recovered MEG solution after being injected to suppress the generation of hydrate when natural gas is produced in the deep sea, High concentrations of MEG can be extracted. The MEG regeneration device 1000 is operated in the ocean and can be applied to all ships and offshore structures that want to regenerate MEG from rich MEG recovered with natural gas after injecting MEG into submarine pipes, but is not limited to this. No, it can also be applied to land plants that require MEG regeneration processes.

The MEG regeneration device 1000 includes a pre-processing unit 100, a re-concentration unit 200, and a regeneration unit 300. Hereinafter, for convenience of description, the pre-processing unit 100, the re-concentration unit 200 and the regeneration unit 300 are grouped and classified into respective components, but accordingly, the respective components may not be clearly divided. In the example, the method of classification may be different for convenience of description or due to properties of components.

The pre-processing unit 100 is subjected to a hydrocarbon removal unit 110 for removing hydrocarbons contained in the rich MEG, a gas removal unit 120 for removing gas from the rich MEG from which hydrocarbons have been removed, and a gas removal unit 120. The pre-treatment vessel 130, which deposits the low-solubility salt from the rich MEG, and the pre-treatment vessel (()) are heated by receiving the rich MEG stored in the pre-treatment vessel 130 through the first circulation line L1 connected to the pre-treatment vessel 130, It includes a pre-treatment heater 140 to return to 130, and a centrifuge 150 to remove the low solubility salt precipitated in the pre-treatment vessel 130 from the rich MEG.

Here, the rich MEG flowing into the hydrocarbon removal unit 110 may include less than about 50wt% MEG. The hydrocarbon removal unit 110 removes the hydrocarbon mixed in the rich MEG, and the gas removal unit 120 removes the gas mixed in the rich MEG. The gas removed by the gas removal unit 120 may be discharged through the gas removal line 121 and processed, and the rich MEG that has passed through the hydrocarbon removal unit 110 and the gas removal unit 120 may be pretreated vessel 130 Is supplied with.

The pretreatment vessel 130 can be maintained at a pressure higher than atmospheric pressure, about 1.5 bar, and precipitates the low solubility salt from the rich MEG containing the low solubility salt, water, and solid solution salt. Low solubility salts are mainly divalent salts, which are poorly soluble in water, and solubility decreases as the temperature increases, resulting in precipitation. Solid solution salts are mainly monovalent salts, soluble in water, and solubility increases with increasing temperature.

The pre-treatment heater 140 receives the rich MEG stored in the pre-treatment vessel 130 through the first circulation line L1 connected to the pre-treatment vessel 130 and heats it to supply it to the pre-treatment vessel 130, through which the pre-treatment vessel 140 is circulated. (130) The low solubility salt is gradually precipitated from the inside. That is, the rich MEG heated by the pre-treatment heater 140 repeatedly circulates to increase the temperature of the rich MEG stored in the pre-treatment vessel 130, thereby causing low solubility salt from the rich MEG stored in the pre-treatment vessel 130. Precipitate.

The centrifuge 150 removes the low solubility salt crystals precipitated through the pretreatment vessel 130 from the rich MEG, and the rich MEG from which the low solubility salt crystals are removed is reconcentrated through the first connection line 101 (200) ).

Here, the first connection line 101 is re-concentrated with the hydrocarbon removal unit 110, the gas removal unit 120, the pretreatment vessel 130, the pretreatment pump 135 and the centrifuge 150 of the pretreatment unit 100 The distillation column 210 of the unit 200 is connected.

And, the above-described first circulation line (L1) is branched from the rear end of the pre-treatment pump 135 of the first connection line 101, and is connected to the front end of the pre-treatment pump 135 of the first connection line 101.

The re-concentration unit 200 receives the rich MEG from which the low solubility salt is removed from the pre-treatment unit 100 and heats it to remove water from the distillation column 210 and the second circulation line L2 connected to the distillation column 210. ) Is provided on the top of the distillation column 210, the product is supplied to the bottom of the distillation column 210 to be heated and returned to the distillation column 210, and the distillation column 210 includes evaporated water Reflux condenser 220, reflux drum 230 and reflux pump for condensing the gas components supplied through a third circulation line (L3) connected to the top of the distillation column 210 and returning some of them to the distillation column 210 240).

The re-concentration unit 200 generates lean MEG by evaporating water from the rich MEG using the difference in the break point between water and MEG through the distillation column 210, and regenerating it through the second connection line 102 It can be supplied to the unit 300. At this time, the re-concentration unit 200 may remove approximately 80% to 90% of water from the rich MEG through the distillation column 210. The second connection line 102 connects the distillation column 210 of the re-concentration unit 200 and the flash separator 310 of the regeneration unit 300.

Specifically, the break point of water contained in the rich MEG is 100 ° C at atmospheric pressure, the break point of the MEG is about 198 ° C, and the break point of the solid solution salt is much higher than that of the MEG.

Distillation column 210 may be operated between about 128 ℃ to 140 ℃ having a high temperature compared to the pre-treatment vessel 130 described above. The distillation column 210 may heat the rich MEG to evaporate water having the lowest breaking point, and repeatedly evaporate water through multi-stage distillation.

At this time, the reboiler 215 receives the product at the bottom of the distillation column 210 and heats it to approximately 137 ° C to circulate repeatedly to the distillation column 210, through which water is evaporated gradually from the rich MEG stored in the distillation column 210. Lean MEG is produced.

Some of these lean MEGs are sent to the regeneration unit 300 through the second connection line 102, and the other part of the regeneration drum 340 of the third connection line 103 to be described later through the mixing line 104. After flowing into the, it is stored in the MEG storage tank 500.

The reflux condenser 220 condenses gas components including water evaporated from the distillation column 210.

The reflux drum 230 separates gas components condensed by the reflux condenser 220. A gaseous discharge line 201 for discharging the gaseous fluid may be connected to the reflux drum 230.

The reflux pump 240 re-supplies some of the liquid fluid discharged from the reflux drum 230 to the top of the distillation column 210 through the third circulation line L3. At this time, the remaining part of the liquid fluid discharged from the reflux drum 230 may be discharged through the condensate discharge line 202 connected to the rear end of the reflux pump 240 of the third circulation line L3.

Here, the ejector 410 may be provided as a vacuum means at the front end of the reflux condenser 220 of the third circulation line L3. The ejector 410 ejects the driving fluid flowing toward the first inlet toward the outlet at a high speed to inhale gas components at the top of the distillation column 210 through the second inlet, and the distillation column 210 and reboiler at the front end of the ejector 410 Let 215 be operated under reduced pressure in a vacuum. The driving fluid is supplied to the first inlet of the ejector 410 through the driving fluid supply line L5 connected to the ejector 410, and through the third circulation line L3 connected to the second inlet side of the ejector 410. The gas component of the upper portion of the distillation column 210 is sucked. The medium pressure or high pressure driving fluid passing through the ejector 410 may be changed to a low pressure high temperature driving fluid. The driving fluid used in the ejector 410 may include, for example, steam or compressed air.

Through this, the re-concentration unit 200 may be operated under reduced pressure below atmospheric pressure to lower the temperature of the distillation column 210 and prevent salt from being deposited in the distillation column 210 and the reboiler 215.

As another example, referring to FIG. 2, an ejector 410 may be provided at a rear end of the reflux drum 230 of the third circulation line L3.

At this time, the ejector 410 ejects the driving fluid flowing toward the first inlet toward the outlet at a high speed to inhale gas components of the reflux drum 230 through the second inlet, and the reflux drum 230 before the ejector 410 , The reflux condenser 220, the distillation column 210 and the reboiler 215 to operate under reduced pressure in a vacuum.

As another example, referring to FIG. 3, a first vacuum pump 420 may be provided as a vacuum means at the rear end of the reflux drum 230.

At this time, the first vacuum pump 420 is provided to be connected to the gaseous discharge line 201 for discharging the gaseous components of the reflux drum 230, and sucks the gaseous components of the reflux drum 230 through the gaseous discharge line 201. , The reflux drum 230 of the front end, the reflux condenser 220, the distillation column 210 and the reboiler 215 are operated under reduced pressure in a vacuum. The first vacuum pump 420 may include, for example, a liquid ring vacuum pump.

Through this, as in the ejector 410 described above, the re-concentration unit 200 may be operated under reduced pressure below atmospheric pressure to prevent salt from being deposited in the distillation column 210 and the reboiler 215.

Meanwhile, the regeneration unit 300 receives the lean MEG from which water is removed by the distillation column 210 through the second connection line 102, and the flash separator 310 and the flash separator to remove the solid solution salt from the lean MEG. To the top of the recirculation heater 320 and the flash separator 310 that receives the product under the flash separator 310 and heats it through the fourth circulation line L4 connected to the 310 to return it to the flash separator 310. It is provided, and includes a regenerative condenser 330 for condensing gas components above the flash separator 310, and a regeneration drum 340 for gas-liquid separation of MEG condensed by the regenerative condenser 330.

The flash separator 310 may be operated under reduced pressure, and vacuum may be formed thereon using a vacuum distillation method using the principle of easily evaporating in a vacuum state, thereby evaporating the lean MEG supplied from the reconcentration unit 200. . At this time, water is evaporated with the MEG from the lean MEG flowing into the flash separator 310 and converted into a gas state. That is, since approximately 10% to 20% of water may be contained in the lean MEG supplied from the re-concentration unit 200, the gas component evaporated by the flash separator 310 may include water together with MEG. At this time, the solid solution salt remaining without evaporation may be removed through a salt separator 325 in a slurry state.

The salt separator 325 is branched from the rear end of the flash pump 315 of the fourth circulation line L4 to be provided in the salt removal circulation line 301 connected to the rear end of the flash pump 315 of the fourth circulation line L4. You can.

The salt separator 325 separates the solid solution of the solid solution from the slurry and the solution of the solid solution in the liquid phase, removes the solid solution of the solid solution, and removes the solution of the solid solution in the solid phase. Return to the front end of the flash pump 315 of the fourth circulation line (L4) through the line (301).

The flash pump 315 supplies some of the products under the regeneration unit 300 to the recirculation heater 320 through the fourth circulation line L4.

The recirculation heater 320 receives the product under the flash separator 310 through the flash pump 315 and heats it to return it to the top of the flash separator 310.

The gas components (MEG and water) above the flash separator 310 are condensed by the regeneration condenser 330 and then supplied to the regeneration drum 340.

The regeneration drum 340 separates the product condensed by the regeneration condenser 330 by gas-liquid separation. The regeneration drum 340 may be connected to the side of the second vacuum pump 430 and the suction line 302, thereby allowing the regeneration unit 300 to operate under reduced pressure. That is, the regeneration drum 340, the regeneration condenser 330, the flash separator 310, and the recirculation heater 320 at the front end of the regeneration drum 340 may be operated under reduced pressure in a vacuum state.

In this case, referring to FIG. 4 as another example, the above-described second vacuum pump 430 is omitted, and the front end of the ejector 410 of the regeneration drum 340 and the gas phase discharge line 201 is connected through the suction line 302. By doing so, the regeneration unit 300 may be operated under reduced pressure. In this case, the fluid of the gas phase of the regeneration drum 340 may be discharged after being sucked through the second inlet of the ejector 410. For the ejector 410 of the weather discharge line 201, refer to FIG. 2 described above.

Referring to FIG. 5 as another example, the above-described second vacuum pump 430 is omitted, and the front end of the first vacuum pump 420 of the regeneration drum 340 and the gas phase discharge line 201 is the suction line 302. It is also possible to connect to the regeneration unit 300 to operate under reduced pressure. For the first vacuum pump 420 of the gas phase discharge line 201, refer to FIG. 3 described above.

The liquid products (MEG and water) stored in the regeneration drum 340 described above are supplied to the MEG storage tank 500 through the third connection line 103.

The third connection line 103 connects the flash separator 310, the regeneration condenser 330, the regeneration drum 340, and the MEG storage tank 500.

In the MEG storage tank 500, not only the liquid product of the above-mentioned regeneration drum 340 introduced through the third connection line 103, but also some of the lean MEG from which water is removed through the re-concentration unit 200 is mixed. It can be introduced through line 104 and stored together. Through this, the concentration of the solid solution salt contained in the lean MEG can be reduced, and the generation of scale due to the solid solution salt can be prevented.

In the MEG storage tank 500, a MEG solution containing approximately 80 wt% or more of MEG, a small amount of water, and a salt of less than approximately 3 wt% may be finally stored, and MEG may be additionally added if necessary.

MEG solution stored in the MEG storage tank 500 can be sent to the seabed to suppress hydrate production in the pipeline.

In the above, specific embodiments have been illustrated and described. However, the present invention is not limited to the above-described embodiments, and those of ordinary skill in the art to which the invention pertains can perform various changes without departing from the gist of the technical spirit of the invention as set forth in the claims below. Will be able to.

100: pre-processing unit 101: first connection line
102: second connection line 103: third connection line
104: mixing line 110: hydrocarbon removal unit
120: gas removal unit 130: pre-treatment vessel
140: pre-treatment heater 150: centrifuge
200: re-concentration unit 210: distillation column
215: reboiler 220: reflux condenser
230: reflux drum 240: reflux pump
300: playback unit 310: flash separator
320: recirculation heater 325: salt separator
330: regeneration condenser 340: regeneration drum
410: ejector 420: first vacuum pump
430: second vacuum pump 500: MEG storage tank
L1: First circulation line L2: Second circulation line
L3: 3rd circulation line L4: 4th circulation line
L5: Drive fluid supply line

Claims (5)

delete delete A distillation column that generates lean MEG by evaporating water from the rich MEG using the difference between the water and the MEG receiving the rich MEG from which the low solubility salt has been precipitated from the pretreatment unit is supplied and heated. A reboiler returning to the distillation column, a reflux condenser provided on the top of the distillation column, and condensing gas components including water evaporated from the distillation column, and separating the condensed gas components into gas-liquid and part of the liquid fluid. A reconcentration unit comprising a reflux drum returned to the distillation column;
A regeneration unit for removing the solid solution salt from the lean MEG; And
It is disposed at the rear end of the reflux drum, the ejector connected to the gaseous discharge line for discharging the gas component of the reflux drum; includes,
The regeneration unit is supplied with a lean MEG from which water is removed from the re-concentration unit, and a flash separator for removing solid solution salt from the lean MEG,
A regenerated condenser condensing the gas component above the flash separator,
A regeneration drum for gas-liquid separation of the product condensed by the regeneration condenser,
The ejector ejects the driving fluid flowing toward the first inlet at a high speed toward the outlet to inhale the gas component of the reflux drum through the second inlet, so that the re-concentration portion at the front end is operated under reduced pressure in a vacuum state.
MEG regeneration device that is connected to the intake line between the regeneration drum and the front end of the ejector of the gas phase discharge line, so that the regeneration unit is operated under reduced pressure. delete delete

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