JP2010215592A - Method for regenerating amine liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform an efficient treatment regenerating amine liquid containing a thermally stable amine salt by a simple device and operation in a good efficiency inexpensively, removing the thermally stable amine salt by using inexpensive ion-exchanging resins in a good efficiency, performing the regeneration of the ion-exchanging resins and the treatment of discharged liquid from the regeneration stably in a high efficiency, improving the utilizing rate of the amine and reducing the amine content in discharged water from the regeneration. <P>SOLUTION: This method for regenerating the amine liquid comprises the steps of: thermally decomposing rich amine liquid obtained by making the amine liquid in contact with an acidic gas in an absorber column 11 to absorb/remove the acid component at a regeneration column 12; neutralizing primarily regenerated lean amine liquid obtained by releasing the acidic gas and circulating it to the absorber column 11, liquid-passing a part of the liquid through cation- and anion-exchanging resin layers 5a, 6a to secondarily regenerate by adsorbing the cation and anion contained in the lean amine liquid and circulating it to the absorber column. As the cation- and anion-exchanging resin layers, used strongly acidic cation- and strongly basic anion-exchanging resins are employed which are used for the removal of the neutral salt and having a reduced total exchanging capacity and neutral salt-decomposing capacity. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for regenerating an amine solution that has absorbed an acid component, and more particularly to a method for efficiently regenerating an amine solution that has absorbed an acid component using an ion exchange resin.

  In oil refining and other processes, acid gases containing hydrogen sulfide, carbon dioxide, and other acid components are generated. Such acid gas absorbs and removes the acid component by contacting with an amine liquid (lean amine) such as alkanolamine in an absorption tower as a gas purification step, and the purified gas is sent to the process. The amine solution (rich amine) that has absorbed the acid component is introduced into the regeneration tower, and rectified using a reboiler as a heat source, thereby decomposing the thermally decomposable amine salt by steam stripping, and the air-dissipating acid component is removed. Release and primary regeneration of the amine. The regenerated amine liquid (lean amine) circulates in the absorption tower and is used to absorb and remove the acid component. The released acidic gas such as hydrogen sulfide and carbon dioxide gas is sent to each recovery device.

  The acid component contained in the acid gas is mainly hydrogen sulfide and carbon dioxide, but in addition to this, trace amounts of carbonyl sulfide, hydrogen cyanide, formic acid, acetic acid, oxalic acid, thiocyanic acid, thiosulfuric acid, and other inorganic acids. Included as All the acid components contained in these acidic gases are absorbed by the amine liquid in the absorption tower and become amine salts. In the regeneration tower, thermally decomposable amine salts such as hydrogen sulfide and carbon dioxide amine salts are thermally decomposed, and separated acid gases such as hydrogen sulfide and carbon dioxide are released to the outside of the system. Primary playback is performed. However, heat-stable amine salts (hereinafter sometimes referred to as HSAS), such as amine salts such as formic acid, acetic acid, oxalic acid, thiocyanic acid, thiosulfuric acid, and other inorganic acids, are not used in the regeneration tower. It is not decomposed and accumulates in the amine solution. If such heat-stable amine salt (HSAS) accumulates, the absorption efficiency of the amine liquid in the absorption tower decreases, and if it becomes 2 to 3% by weight, it causes corrosion of the apparatus and foaming during operation. It is desired to remove from the liquid.

  As a method for removing HSAS from the amine solution, there is a method of neutralizing the amine solution with an alkali such as sodium hydroxide or potassium carbonate. This method decomposes the amine salt by injecting alkali into the amine solution to form formic acid, acetic acid, oxalic acid, thiocyanic acid, thiosulfuric acid, other inorganic acids, etc., which constitute the HSAS. The weakly diffusible weak acid is eluted to release metal salts such as sodium and potassium to regenerate the amine solution. The metal salt of the heat-stable acid component produced here is not a hindrance to absorption if the concentration is low, but it is not a fundamental treatment because the solubility is low, and if it exceeds the solubility, it precipitates and causes harm.

  As a method for substantially removing HSAS from an amine solution, there is an ion exchange method. In Patent Document 1 (Japanese Patent Laid-Open No. 5-294902), by passing an amine solution through a cation exchange resin layer and an anion exchange resin layer, It is described that cations and anions in the amine liquid are removed and the amine liquid is subjected to secondary regeneration. Here, depending on the characteristics of the anion bonded to the amine constituting the HSAS, the strong anion exchange resin layers of type I and type II are arranged in series to remove the anion. These resins are regenerated by regenerating the resin by passing an acid such as sulfuric acid for regenerating the cation exchange resin, and passing an alkali such as sodium hydroxide for regenerating the anion exchange resin, and subjecting it to the treatment of the amine solution. Yes.

  In the conventional method for regenerating an amine liquid including Patent Document 1, an amine liquid (lean amine) obtained by removing gas diffused acidic gas such as hydrogen sulfide and carbon dioxide from a regeneration tower in the gas purification process is attached to the gas purification process. The lean amine solution is secondarily regenerated by removing the cations and anions in the lean amine solution by passing through the cation exchange resin layer and the anion exchange resin layer. In this case, in order to remove cations and anions in the amine solution at a high removal rate, the lean amine solution is secondarily regenerated using a new resin having high ion exchange performance such as total exchange capacity and neutral salt decomposition capacity. Yes. Regeneration of the cation exchange resin and anion exchange resin adsorbing cations and anions is performed at a high level by passing a large amount of regenerant such as acid, salt, alkali, etc. through the cation exchange resin layer and the anion exchange resin layer. The removal rate of cations and anions is increased.

  However, the secondary regeneration of the lean amine liquid does not need to be performed for all the amine liquids. A part of the lean amine liquid circulating to the absorption tower is diverted to secondary regeneration, and the secondary regenerated amine liquid is circulated. If the operation of mixing with the lean amine solution is repeated, impurities in the lean amine solution are gradually removed, and an amine solution having excellent absorption characteristics can be used for removing the acidic gas. Therefore, if impurities can be removed to a considerable extent without removing impurities at a high removal rate, the impurities in the lean amine solution are gradually removed, and an amine solution having excellent absorption characteristics can be obtained. In addition, since HSAS is a weak acid salt, it can be processed without using a resin having high ion exchange performance such as total exchange capacity and neutral salt decomposition capacity, and an inexpensive process is required.

  In general, in ion exchange, liquid flow is stopped at a flow-through point where ions to be removed leak, and the regeneration is started. When such a regeneration method is adopted, the amine to be recovered is transferred into the regeneration drainage, and the amine is recovered. However, there are problems in that the yield of the liquid becomes worse, the processing of the regenerated drainage liquid becomes difficult, and the processing cost increases.

Japanese Patent Laid-Open No. 5-294902

  An object of the present invention is to regenerate an amine liquid containing a heat-stable amine salt efficiently and inexpensively with a simple apparatus and operation, and also efficiently remove the heat-stable amine salt using an inexpensive ion exchange resin. The regeneration of the ion-exchange resin and the regeneration drainage treatment can be performed stably and with high efficiency and easily, and the amine utilization rate is increased, the amount of amine in the regeneration drainage liquid is reduced, and the efficiency is improved. It is to propose a method for regenerating an amine solution capable of performing a good treatment.

The present invention is the following method for regenerating an amine solution.
(1) an absorption step in which an acidic gas containing an acid component is brought into contact with an amine liquid in an absorption tower to absorb and remove the acid component to produce a rich amine liquid;
An amine primary regeneration step in which a rich amine liquid that has absorbed an acid component is thermally decomposed in a regeneration tower to release a diffusive acidic gas, thereby producing a lean amine liquid by primary regeneration of the rich amine liquid;
By neutralizing the lean amine solution with an alkali, the accumulated heat-stable lean amine salt is decomposed to release a salt of a weakly diffusible weak acid, and the amine solution is neutralized by circulating the lean amine solution to the absorption tower; ,
A part of the lean amine liquid is passed through the cation exchange resin layer and the anion exchange resin layer, and the cation contained in the lean amine liquid and the anion constituting the heat-stable amine salt are exchanged and adsorbed to regenerate and absorb the lean amine liquid. A method comprising an amine secondary regeneration step that is circulated through the tower,
Strongly acidic cation exchange resin and strong basic anion exchange resin used for the removal of neutral salt as cation exchange resin layer and anion exchange resin layer in amine secondary regeneration step, total exchange capacity and neutral salt decomposition capacity An amine solution characterized by using a cation exchange resin layer filled with a used cation exchange resin having a reduced amount and an anion exchange resin layer filled with a used anion exchange resin having a reduced total exchange capacity and neutral salt decomposition capacity How to play.
(2) When the flow rate of the lean amine solution at the flow-through point of the cation exchange resin layer is 100%, the cation exchange resin layer is regenerated when the flow rate of the lean amine solution reaches 103 to 106%, and anion exchange is performed. The method according to (1) above, wherein the anion exchange resin layer is regenerated at a flow-through point of the resin layer.
(3) As a cation exchange resin layer and an anion exchange resin layer, an ion exchange apparatus including a detachable exchange type cation exchange unit and an anion exchange unit filled with a used cation exchange resin and a used anion exchange resin is provided,
The cation exchange unit filled with the regenerated cation exchange resin and the anion exchange unit filled with the regenerated anion exchange resin are attached to the ion exchange apparatus, and the cation and heat contained in the lean amine liquid are passed through the lean amine liquid. Adsorption and removal of anions constituting the stable amine salt to regenerate the amine solution,
The cation exchange unit adsorbing cations and anions and the anion exchange unit are desorbed from the ion exchange device and replaced with a cation exchange unit filled with a regenerated cation exchange resin and an anion exchange unit filled with a regenerated anion exchange resin. And
The method according to (1) or (2) above, wherein the secondary regeneration of the amine liquid is continued.
(4) Desorbing the cation exchange unit and anion exchange unit adsorbing cations and anions from the ion exchange device;
The method according to (3) above, wherein the desorbed cation exchange resin of the cation exchange unit and the anion exchange resin of the anion exchange unit are regenerated by a resin regenerator.

  In the present invention, the amine liquid to be regenerated is absorbed to purify the gas by absorbing and removing the acid component from the acid gas containing hydrogen sulfide, carbon dioxide gas, and other acid components generated in petroleum refining and other processes. It is an amine liquid used as a liquid. Examples of such amine liquids include alkanolamines and other amine liquids generally used in the gas refining process of petroleum refining and other processes. Specific examples thereof include alkanolamines such as monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), diglycolamine (DGA), methyldiethanolamine (MDEA), and diisopropanolamine (DIPA). Although used, other amines may be used. These amine solutions are usually used as an aqueous solution of 15 to 55% by weight.

  In the present invention, the gas refining step is a step of purifying an acid gas containing hydrogen sulfide, carbon dioxide gas, and other acid components generated in petroleum refining and other processes, and an absorption step for absorbing the acid gas, and an amine primary regeneration. Process. The absorption process is a process in which an acid gas containing an acid component is brought into contact with the amine liquid in the absorption tower to absorb and remove the acid component to produce a rich amine liquid. The primary amine regeneration process is an amine liquid that has absorbed the acid component. Is a step of regenerating an amine solution by thermally decomposing it in a regeneration tower to produce a lean amine solution. As the absorption tower and the regeneration tower, a packed tower and other conventionally used gas-liquid contact towers are used, respectively.

  In the absorption step, the acid gas and the amine liquid (lean amine) are dispersed in the absorption tower, for example, by contacting them in a countercurrent manner, so that the acid component is absorbed into the amine liquid and removed from the gas to be processed, and the rich amine liquid Is generated. Purified gas is sent to the process. Here, fusible gases such as hydrogen sulfide and carbon dioxide that form thermally decomposable amine salts are also used as formic acid, acetic acid, oxalic acid, thiocyanic acid, thiosulfuric acid, inorganic that form thermally stable amine salts (HSAS). Non-diffusible gases such as acids are also absorbed and form thermally decomposable amine salts and thermally stable amine salts. In this case, protons are coordinated to the unshared electron pair of the nitrogen atom that constitutes the amine, so that “protonation” occurs. At this time, the counter ion (anion) that constitutes the acid is Due to the ionic bond, the acid component is absorbed by the amine solution.

  In the primary amine regeneration step, the amine liquid that has absorbed the acid component is thermally decomposed in a regeneration tower to primarily regenerate the amine liquid to produce a lean amine liquid. Thermal decomposition introduces an amine solution (rich amine) that has absorbed an acid component into a regenerator, and rectifies it using a reboiler as a heat source. By thermal stripping, thermal decomposition such as hydrogen sulfide and amine salt of carbon dioxide is possible. The amine salt of is thermally decomposed to release a diffusible acid component such as hydrogen sulfide and carbon dioxide. As a result, the amine is primarily regenerated to produce a lean amine solution, which is circulated through the absorption tower to absorb the acid component. Separated acid gases such as hydrogen sulfide and carbon dioxide are released out of the system, but non-gassing acid components such as formic acid, acetic acid, oxalic acid, thiocyanic acid, thiosulfuric acid and other inorganic acids The heat-stable amine salt (HSAS) such as the amine salt is not decomposed in the regeneration tower, but is circulated to the absorption tower while accumulating in the amine liquid.

  If such HSAS has a low concentration in the amine solution, it is possible to absorb the absorbing acid component. However, if the HSAS is accumulated in the amine solution, the absorption efficiency of the amine solution in the absorption tower decreases, and 2-3 wt. %, It causes corrosion of the apparatus and foaming during operation. Therefore, HSAS is removed from the amine solution. In order to remove HSAS from the amine solution, the amine solution is neutralized with an alkali such as sodium hydroxide or potassium carbonate in the neutralization step, thereby decomposing the accumulated heat-stable lean amine salt and causing difficulty in diffusing. The salt of the weak acid is released and the lean amine solution is circulated in the absorption tower. In this step, the amine solution is neutralized by injecting an alkali to deprotonate it, formic acid, acetic acid, oxalic acid, thiocyanic acid, thiosulfuric acid, which are heat-stable acid components constituting HSAS. Elution of other non-diffusible weak acids such as inorganic acids to liberate metal salts such as sodium and potassium to regenerate the amine solution. The metal salt of the heat-stable acid component produced here is not a hindrance to absorption if the concentration is low, but it is not a fundamental treatment because the solubility is low, and if it exceeds the solubility, it precipitates and causes harm.

  In order to remove the non-air-dissipating acid component constituting HSAS from the amine solution and to secondary regenerate the amine solution, in the present invention, as the secondary amine regeneration step, a part of the lean amine solution is converted into a cation exchange resin layer and an anion. The solution is passed through the exchange resin layer, and the cation and the anion constituting the heat-stable amine salt contained in the lean amine solution are removed by exchange adsorption to regenerate the lean amine solution and circulate it in the absorption tower. In this amine secondary regeneration process, other cations introduced in the absorption process are exchanged for the cation exchange resin layer in addition to the alkali components used for neutralization, such as sodium and potassium, as cations contained in the lean amine solution. Adsorbed. Since it is acidified by cation exchange, a part of the anion is adsorbed to the amine, but the anion adsorbed to the amine and the anion that remains in the liquid without being adsorbed pass through the anion exchange resin layer. Exchange-adsorbed on the resin layer. In such an amine secondary regeneration step, the HSAS in the lean amine liquid is removed, and the secondary regenerated lean amine liquid is circulated to the absorption tower. The amine secondary regeneration step is performed by diverting a part of the lean amine liquid circulating to the absorption tower, and this diversion may be performed before or after the neutralization step.

  The cation exchange resin layer and the anion exchange resin layer in the amine secondary regeneration step are strongly acidic cation exchange resins and strong basic anion exchange resins used for the removal of neutral salts, and the total exchange capacity and neutral salt decomposition A cation exchange resin layer filled with a used cation exchange resin having a reduced capacity and an anion exchange resin layer filled with a used anion exchange resin having a reduced total exchange capacity and neutral salt decomposition capacity are used. As such a used resin, a used resin used for removing neutral salts in water treatment such as pure water production, particularly ultrapure water production, is preferable.

In the conventional method, new resins are used as the cation exchange resin and the anion exchange resin. However, in the present invention, a used resin with reduced performance is used.
The new strong acid cation exchange resin used conventionally has a sulfonic acid group as a cation exchange group, has a total exchange capacity of 1.9 to 2.5 meq / mL-resin, and a neutral salt decomposition capacity of 1.9 to 2 0.0 meq / mL-resin, and a new strong basic anion exchange resin has a quaternary ammonium group as an anion exchange group and a total exchange capacity of 1.2 to 1.4 meq / mL-resin, medium Although the salt decomposition capacity is 1.2 to 1.4 meq / mL-resin, it was found that a resin with reduced performance may be used for secondary regeneration of the amine solution. For this reason, in this invention, it uses for the removal of a neutral salt and uses used resin with which the performance fell.

  Conventionally, for secondary regeneration of lean amine liquid, a new resin with high ion exchange performance such as total exchange capacity and neutral salt decomposition capacity was used to remove cations and anions in amine liquid with high removal rate. The secondary regeneration of the lean amine liquid does not need to be performed for all the amine liquids, but a part of the amine liquid circulating to the absorption tower is diverted to perform secondary regeneration, and the lean amine liquid that circulates the secondary regenerated amine liquid. By repeating the operation of mixing with the liquid, impurities in the lean amine liquid are gradually removed, and an amine liquid having excellent absorption characteristics can be used for removing the acidic gas. Therefore, if impurities can be removed to a considerable extent without removing impurities at a high removal rate, the impurities in the lean amine solution are gradually removed, and an amine solution having excellent absorption characteristics can be obtained.

  That is, conventionally, in order to remove alkali metal ions, which are strong cations such as sodium and potassium, present in the amine solution, a strongly acidic cation exchange resin having a sulfonic acid group as an exchange group is used, and depending on the characteristics of the anion. In addition, although type I and type II strongly basic anion exchange resins having a quaternary ammonium group as an exchange group such as quaternary amine or alkanolamine have been used, secondary regeneration of the lean amine liquid is not necessarily performed as described above. Even if impurities are not removed at a high removal rate, it is sufficient that impurities can be removed to a considerable extent. Since the HSAS to be removed is a salt of a weak acid, the purpose is not required even if the total exchange capacity or neutral salt decomposition capacity is high. It was found that can be achieved. For this reason, in this invention, even if it uses the used resin to which the total exchange capacity | capacitance and neutral salt decomposition capacity fell by use, an efficient process can be performed.

  The used cation exchange resin used in the present invention has a total exchange capacity of 1.0 to 1.9 meq / mL-resin, preferably 1.5 to 1.9 meq / mL-resin, neutral salt decomposition capacity of 1.0 to 1.9 meq / mL-resin, preferably 1.5-1.9 meq / mL-resin, used anion exchange resin has a total exchange capacity of 0.6-1.2 meq / mL-resin, preferably 0 .8-1.2 meq / mL-resin, neutral salt decomposition capacity 0.6-1.2 meq / mL-resin, preferably 0.7-1.2 meq / mL-resin, both preferably 50 Those with a total exchange capacity and neutral salt decomposition capacity of ~ 95%, at best 50-85%, can be used and have such performance at any point from the beginning to the end of use. good.

  A new strong acid cation exchange resin has a sulfonic acid group as a cation exchange group, and has a high total exchange capacity and a neutral salt decomposition capacity. Formation of weakly acidic exchange groups such as groups reduces total exchange capacity and neutral salt decomposition capacity. Also, new strong basic anion exchange resins have quaternary amino groups such as quaternary amines or alkanolamines as anion exchange groups, and have a high total exchange capacity and neutral salt decomposition capacity. The strong basic quaternary amino group is dropped and a weak basic exchange group such as a secondary or tertiary amino group is formed, whereby the total exchange capacity and neutral salt decomposition capacity are lowered.

  In order to remove neutral salts in water treatment such as pure water production, particularly ultrapure water production, it is necessary to use a resin having a high total exchange capacity and a high neutral salt decomposition capacity. Since it is a salt of a weak base, it has been found that even a used cation exchange resin having a reduced total exchange capacity and neutral salt decomposition capacity can be sufficiently removed. Further, since the anion contained in the lean amine solution is a weak base and becomes a weak acid after cation exchange, even a used anion exchange resin having a reduced total exchange capacity and neutral salt decomposition capacity can be sufficiently removed. It is preferable to use H type as the cation exchange resin and OH type resin as the anion exchange resin.

  In order to regenerate the amine liquid by removing the non-air-diffusing acid component constituting HSAS from the amine liquid, the used cation exchange resin and anion exchange resin regenerated externally are attached to the regeneration tower. A plurality of ion exchange devices including a detachable and exchangeable cation exchange unit and an anion exchange unit that are filled and formed with respective resin layers are provided, and the cation exchange unit and the anion exchange unit are located away from these ion exchange devices. It is preferable to provide a resin regeneration apparatus and a regeneration drainage treatment apparatus as a regeneration center that collects the cation exchange resin and the anion exchange resin in a concentrated manner. Here, the meaning of “plurality” means that a plurality of ion exchange devices are provided in association with a plurality of regenerative towers that exist in a dispersed manner, and each regenerative tower has one ion exchange device. It may be provided. The ion exchange device may be provided with other processing devices such as a mechanical filter and an activated carbon adsorption tower.

  The detachable and exchangeable cation exchange unit and anion exchange unit filled with a cation exchange resin and an anion exchange resin to form respective resin layers accommodate the resin in a container that functions as a cation exchange tower and an anion exchange tower, It is preferable that the vessel can be mounted and desorbed simply by connecting and separating the piping by transferring the vessel, but the cation exchange column and the anion exchange column are installed on site, and the transferred cations are transferred into the cation exchange column and the anion exchange column. An exchange unit and an anion exchange unit may be attached and detached.

  In the secondary regeneration of the amine solution, when the lean amine solution containing HSAS is divided and passed through the regenerated cation exchange resin layer and anion exchange resin layer, the potassium contained in the lean amine solution is obtained in the cation exchange resin layer. Cations such as ions are removed by exchange adsorption. At this time, since the cation is a weak acid salt, the used cation exchange resin layer whose performance has deteriorated is sufficiently removed. Amines are also adsorbed, but when other cations are exchange-adsorbed, the amines elute sequentially. By removing the cation, the anion constituting the HSAS is liberated as a weak acid or bonded to an amine. In either case, the anion is removed by being adsorbed on the anion exchange resin layer. In this way, the secondary regeneration of the amine solution is performed, and the secondaryly regenerated amine solution (lean amine solution) is circulated to the absorption tower.

  When secondary regeneration of amine liquid is performed using a plurality of ion exchange devices including a detachable exchange type cation exchange unit and an anion exchange unit, a cation filled with the cation exchange resin and the anion exchange resin regenerated by the resin regeneration device The exchange unit and the anion exchange unit are transferred to and mounted on the plurality of ion exchange devices, respectively, and the lean amine solution containing the HSAS is divided and passed through the attached cation exchange unit and anion exchange unit. Here, in the cation exchange unit, cations such as metal ions contained in the lean amine liquid are exchange-adsorbed and removed by the cation exchange resin. At this time, amine is also adsorbed, but amine is eluted when other cations are adsorbed by exchange. In the anion exchange unit, HSAS is decomposed by the neutral salt resolution of the anion exchange resin, and the anions constituting the HSAS are exchanged and removed. In this way, the secondary regeneration of the amine solution is performed, and the secondaryly regenerated amine solution (lean amine solution) is circulated to the absorption tower.

  If secondary regeneration of the amine liquid is continued, in each cation exchange resin layer and anion exchange resin layer, the respective resins reach saturation depending on the composition, concentration, etc. of HSAS contained in the amine liquid, and the resin is regenerated. I need it. Generally, when the resin reaches saturation and begins to be regenerated, the electrical conductivity of the treatment liquid that passes through the resin layer is measured, and the treatment ends at the point when the electrical conductivity suddenly rises, that is, when the ion leaks. In general, however, the reproduction is started. However, in the cation exchange resin layer, when the cation leaks at the flow-through point, a large amount of amine is adsorbed on the cation exchange resin layer. There are problems in that it is discharged into the regenerated drainage liquid, and the yield of amine is lowered, and the treatment of the regenerated drainage liquid becomes difficult.

  In order to improve such a point, when the flow rate of the lean amine solution at the flow point of the cation exchange resin layer is 100%, the flow rate of the lean amine solution is 103 to 106%, preferably 104 to 105%. At this point, it is preferable to stop the flow of the cation exchange resin layer and perform regeneration. Even in this case, the anion exchange resin layer can be regenerated by stopping the liquid flow at the flow-through point. By passing the liquid after the through point of the cation exchange resin layer, most of the amine adsorbed on the cation exchange resin layer flows out, the yield of the amine is increased, and the treatment of the regenerated waste liquid is facilitated. If the cation exchange resin layer passes through the flow point, the cation flows into the treatment liquid and circulates in the absorption tower, but the cation circulation in the above range is allowed. However, when the amount of the lean amine solution to be passed exceeds 106%, preferably 105%, it becomes difficult to determine the flow-through point of the anion exchange resin layer. It is preferable to stop and regenerate, since it is easy to determine the flow point of the anion exchange resin layer and the anion exchange resin layer can be regenerated accurately.

  When secondary regeneration of an amine liquid is performed using a plurality of ion exchange devices including a detachable exchange type cation exchange unit and an anion exchange unit, each of the cation exchange units is provided in a plurality of dispersed ion exchange devices. In each cation exchange unit and anion exchange unit, depending on the composition and concentration of HSAS contained in the amine solution, the resin reaches saturation at different times and is regenerated into resin at different times. Is required. The need for regeneration occurs once, and it is difficult to regenerate each time and process the regeneration drainage. Therefore, when regeneration is necessary, the cation exchange unit and the anion exchange unit are used as a regeneration center. The cation exchange resin and the anion exchange resin that are collected in the resin regeneration apparatus can be intensively regenerated by the resin regeneration apparatus.

  In this case, the regeneration of the cation exchange resin and the anion exchange resin is performed when the resin reaches saturation in each of the cation exchange unit and the anion exchange unit, and the regeneration needs to be performed. The exchange unit can be detached from each ion exchange device and collected in a resin regeneration device, and the recovered cation exchange resin of the cation exchange unit and the anion exchange resin of the anion exchange unit can be regenerated by the resin regeneration device. The cation exchange unit and the anion exchange unit may be exchanged separately when the regeneration needs to occur. In this case, the cation exchange unit or the anion exchange unit filled with the regenerated cation exchange resin or the anion exchange resin. Are exchanged, and the saturated cation exchange unit or anion exchange unit can be recovered in the resin regenerator.

  The resin regeneration unit is equipped with a cation exchange unit and an anion exchange unit filled with a cation exchange resin and an anion exchange resin. When regenerating in the format, countercurrent regeneration can be performed to increase the regeneration efficiency without disturbing the exchange zone. In addition, when a cation exchange resin and an anion exchange resin are extracted from a plurality of cation exchange units and anion exchange units and introduced into a dedicated resin regeneration tower to regenerate the mixed resin, Although the resin can be collected and regenerated at once, it is necessary to extract and refill the resin.

  Regeneration of the cation exchange resin and the anion exchange resin in the resin regenerator is performed by attaching a cation exchange unit or anion exchange unit to the resin regenerator, or introducing the resin into a dedicated resin regeneration tower and injecting a regenerant. Mineral acids such as hydrochloric acid and sulfuric acid can be used as the regenerating agent for the cation exchange resin, and the regenerating agent for the anion exchange resin can be an alkali such as sodium hydroxide, or a combination thereof with a salt such as sodium chloride or potassium chloride. Well-known ones can be used. The regeneration operation is performed in the same process as the regeneration of a general ion exchange resin, such as backwashing, chemical injection, extrusion, and washing. However, in some cases, a part of the process, for example, the backwashing process can be omitted. When regenerated in the state of a unit, it can be transferred to the place where the ion exchange device is installed as a replacement unit after regeneration. However, when regenerated in a dedicated resin regeneration tower, the unit is filled with the resin after regeneration. Can be transferred to the place where the ion exchanger is installed.

  The regeneration drainage generated in the resin regeneration device can be processed by the regeneration drainage treatment device. The regeneration drainage treatment apparatus is installed in a place away from the ion exchange apparatus in association with the resin regeneration apparatus as a regeneration center. As the regenerative drainage treatment apparatus, an apparatus having a suitable treatment method is selected according to the composition, concentration, property, etc. of the regenerated wastewater to be generated. The regenerated waste liquid contains not only ordinary salts such as metal salts but also persistent COD components such as formic acid, acetic acid, oxalic acid, thiocyanic acid and thiosulfuric acid, and BOD components. Such regeneration drainage is difficult to process when it occurs once, but regeneration drainage can be generated substantially continuously by collecting a large number of units and performing intensive regeneration.

  In this way, by installing the regeneration drainage treatment apparatus along with the resin regeneration apparatus as the regeneration center, it is possible to continuously supply wastewater to the regeneration drainage treatment apparatus and perform continuous processing. For this reason, as the regeneration drainage treatment apparatus, biological treatment with easy treatment operation and high treatment efficiency can be adopted, but in addition to or instead of this, treatment other than biological treatment such as chemical decomposition treatment with an oxidizing agent. The method can also be adopted. In either case, the cation exchange resin regeneration effluent and the anion exchange resin regeneration effluent are mixed and neutralized, or an acid or alkali is added to adjust the pH, or precipitates are generated thereby. In some cases, a solid-liquid separator can be provided.

  When processing the regenerated effluent with such a regenerated effluent treatment device, the cation exchange resin regenerated effluent and the regenerated effluent of the anion exchange resin are mixed and neutralized by introducing them into the storage tank, and homogenized. A part thereof can be detoxified by adjusting the pH if necessary and introducing it into a biological treatment apparatus or the like to perform biological treatment or the like. As the biological treatment apparatus, an aerobic biological treatment apparatus such as activated sludge treatment is preferable, but an anaerobic biological treatment apparatus may be used. As the chemical decomposition treatment apparatus using an oxidizing agent, a chemical decomposition treatment apparatus using an oxidizing agent such as a hydrogen peroxide-based oxidizing agent or a chlorine-based oxidizing agent can be used. In addition, other processing apparatuses such as coagulation sedimentation processing can be employed.

  In biological treatment equipment, when biological sludge such as activated sludge is generated, the activity of the organism decreases unless the substrate is continuously supplied. Can be maintained. Even in the case of chemical decomposition treatment with an oxidant and other treatments, if the liquid to be treated is stopped, the treatment cannot be performed or the efficiency is lowered, but the regenerated waste liquid is continuously supplied as described above. As a result, even in the case of other processes, the process can be performed stably.

  An acidic gas containing an acid component is brought into contact with the amine liquid in the absorption tower to absorb and remove the acid component to produce a rich amine liquid, and the amine liquid that has absorbed the acid component is thermally decomposed in the regeneration tower to remove the amine liquid. Primary regeneration produces a lean amine solution, and the lean amine solution is passed through an ion exchange device to adsorb and remove the cations contained in the lean amine solution and the anions constituting the heat-stable amine salt, thereby secondary regeneration of the amine solution. In this case, since the ion exchange resin is used until it is saturated, the resin regeneration interval is long, for example, weekly or monthly. It is difficult to perform regeneration at such long intervals because the regeneration and regeneration drainage treatment itself is an abrupt matter, and it is difficult to perform regeneration and drainage treatment suddenly. In particular, there is a problem that biological activity cannot be maintained by biological treatment.

  In such a case, in order to perform the drainage process effectively, a resin regeneration unit is installed as a regeneration center so that the regeneration of the ion exchange resin and the regeneration drainage process can be continued. In an absorption tower and a regeneration tower as a gas purification apparatus in which a regeneration wastewater treatment apparatus is installed and dispersed, an ion exchange apparatus capable of mounting and desorbing a cation exchange unit and an anion exchange unit can be installed. Then, the cation exchange unit and the anion exchange unit are moved back and forth between these devices, and the cation and the anion contained in the amine liquid are adsorbed on the cation exchange unit and the anion exchange unit in the ion exchange device, respectively, and are collected in the regeneration center. Regeneration and regeneration drainage treatment operations by regenerating the collected resin almost continuously with the resin regeneration device as a continuous, and processing the regeneration drainage continuously with the regeneration drainage treatment device provided along with this Can be made into a routine to efficiently perform the regeneration drainage treatment, ensure the stability of the treatment, and maintain a high biological activity in the biological treatment to increase the treatment efficiency.

  According to the present invention, an acid gas containing an acid component is brought into contact with an amine liquid in an absorption tower to absorb and remove the acid component to produce a rich amine liquid, and the rich amine liquid that has absorbed the acid component is regenerated. By thermally decomposing in the tower and releasing gas diffused acid gas, primary regeneration step of primary regeneration of rich amine liquid to produce lean amine liquid, and neutralization of lean amine liquid with alkali, Decompose the accumulated heat-stable lean amine salt to release the salt of weakly diffusible weak acid and circulate the lean amine liquid to the absorption tower, and a part of the lean amine liquid is a cation exchange resin layer And passing through the anion exchange resin layer, the cation contained in the lean amine liquid and the anion constituting the heat-stable amine salt are exchanged and adsorbed, and the lean amine liquid is secondarily regenerated. In the method including the amine secondary regeneration step that is circulated in the absorption tower, the strongly acidic cation exchange resin and the strong cation exchange resin layer and the anion exchange resin layer used in the amine secondary regeneration step are used as the cation exchange resin layer and the anion exchange resin layer. Cation exchange resin layer filled with used cation exchange resin with reduced total exchange capacity and neutral salt decomposition capacity, and used anion with reduced total exchange capacity and neutral salt decomposition capacity Since the amine liquid is regenerated using the anion exchange resin layer filled with the exchange resin, the amine liquid containing the heat-stable amine salt can be regenerated efficiently and inexpensively with a simple apparatus and operation. The heat-stable amine salt can be efficiently removed using a new ion exchange resin, and the regeneration and drainage treatment of the ion exchange resin is also safe. To can be easily performed with high efficiency and increase the utilization rate of the amine, to reduce the amine content in the playback drainage, efficient processing can be performed.

  Further, when the flow rate of the lean amine liquid at the flow-through point of the cation exchange resin layer is 100%, the cation exchange resin layer is regenerated when the flow rate of the lean amine liquid reaches 103 to 106%, and the anion exchange resin layer By regenerating the anion exchange resin layer at the flow-through point, most of the amine adsorbed on the cation exchange resin layer flows out, increasing the yield of the amine and facilitating the treatment of the regenerated drainage. In addition, it is easy to determine the flow-through point of the anion exchange resin layer, and the anion exchange resin layer can be accurately regenerated.

  As the cation exchange resin layer and the anion exchange resin layer, a detachable exchange type cation exchange unit filled with a used cation exchange resin and a used anion exchange resin and an ion exchange device including the anion exchange unit are provided, and the regenerated cation A cation exchange unit filled with an exchange resin and an anion exchange unit filled with a regenerated anion exchange resin are attached to the ion exchange device, and the cation and heat-stable amine salt contained in the lean amine liquid are passed through the lean amine liquid. An anion liquid containing a heat-stable amine salt is obtained by adsorbing and removing the anions constituting the secondary solution, secondary regeneration of the amine liquid, exchanging the cation exchange unit and the anion exchange unit, and continuing secondary regeneration of the amine liquid. Can be played efficiently with simple equipment and operation Even when regenerating an ion exchange resin adsorbing a hardly decomposable component, it is possible to efficiently regenerate the amine liquid by exchanging the ion exchange resin adsorbing the hardly decomposable component generated from the heat stable amine salt. In addition, regeneration of the ion exchange resin and regeneration drainage treatment can be performed stably with high efficiency and easily.

  The cation exchange unit and anion exchange unit that adsorbs cations and anions are desorbed from the ion exchange unit, and the cation exchange resin of the desorbed cation exchange unit and the anion exchange resin of the anion exchange unit are regenerated with a resin regenerator to achieve thermal stability. Can efficiently regenerate the amine liquid containing the soluble amine salt with simple equipment and operation, and can effectively regenerate the ion exchange resin that adsorbs the hardly decomposable component generated from the heat stable amine salt. In addition, the regeneration drainage treatment can be performed stably with high efficiency and easily.

It is a flowchart of the whole processing apparatus of embodiment. It is a flowchart of the gas purification apparatus and ion exchange apparatus of embodiment. It is a flowchart of the resin reproduction | regeneration apparatus and reproduction | regeneration drainage processing apparatus of embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a flowchart of the entire processing apparatus, FIG. 2 is a flowchart of a gas purification apparatus and an ion exchange apparatus, and FIG. 3 is a flowchart of a resin regeneration apparatus and a regeneration drainage treatment apparatus. 1 to 3, 1 is a gas purification device, 2 is an ion exchange device, 3 is a resin regeneration device, 4 is a regeneration drainage treatment device, 5 is a cation exchange unit, and 6 is an anion exchange unit.

  In FIG. 1, a gas refining device 1 is provided in an oil refining or other process, and a plurality of gas refining devices 1 are distributed in various places. A plurality of ion exchange devices 2 are provided in a 1: 1 correspondence with the plurality of gas purification devices 1, but a plurality of ion exchange devices 2 may be provided in one gas purification device 1. One resin regeneration device 3 is provided as a regeneration center at a location away from these ion exchange devices 2, and one regeneration drainage treatment device 4 is provided in association therewith. A detachable and exchangeable cation exchange unit 5 and anion exchange unit 6 are transported between the plurality of ion exchange devices 2 and the resin regenerating device 3, and the cation contained in the amine liquid is attached to the ion exchange device 2. And anion are adsorbed to the cation exchange unit 5 and the anion exchange unit 6, respectively, and then desorbed and transferred to the resin regenerator 3 to regenerate the resin. 2 and 3, the cation exchange unit 5 is filled with a used cation exchange resin to form a cation exchange resin layer 5a. The anion exchange unit 6 is filled with a used anion exchange resin. An anion exchange resin layer 6a is formed.

  In FIG. 2, in the gas purification apparatus 1, an absorption tower 11 and a regeneration tower 12 communicate with each other via pumps P <b> 1 and P <b> 2 and heat exchangers 13 and 14 through lines L <b> 1 and L <b> 2. The absorption tower 11 and the regeneration tower 12 are provided with packed layers 15 and 16 inside, and are configured to absorb and regenerate by gas-liquid contact. Lines L3 and L4 are connected to the absorption tower 11, and the acidic gas containing the acid component entering from the line L3 is brought into contact with the lean amine liquid entering from the line L2 in the packed bed 15, thereby absorbing and removing the acid component. The purified gas is returned to the process from the line L4, and the produced rich amine liquid is sent to the regeneration tower 12 from the line L1. In the regeneration tower 12, steam heating is performed in the reboiler 17, thereby steam stripping the rich amine liquid entering from the line L1, and decomposing a thermally decomposable amine salt such as an amine salt of hydrogen sulfide or carbon dioxide to remove an acid component. The amine is first regenerated to produce a lean amine solution, and the lean amine solution is circulated from the line L2 to the absorption tower 11. A line L10 communicates with the line L2, and an alkali such as potassium carbonate is injected to neutralize the lean amine solution.

  The ion exchange device 2 is provided with couplings 1a, 1b, 1c,... On a support frame base 21 connected to lines L8 and L9 that branch to form a bypass path before and after the line L10 in the line L2. Lines L11, L12, L13 for connecting the couplings 1b and 1c, 1d and 1e,... Are provided, and a removable exchangeable mechanical filter unit 22 having the couplings 2a, 2b, 2c,. The unit 23, the cation exchange unit 5 and the anion exchange unit 6 are detachably mounted via couplings 1a, 1b, 1c,. The lines L12, L13, and L9 are provided with electrical conductivity meters 3a, 3b, and 3c, and are input to the control device 24. The activated carbon unit 23, the cation exchange unit 5 and the anion exchange unit 6 are filled with an activated carbon layer 23a, a cation exchange resin layer 5a and an anion exchange resin layer 6a, respectively, and the couplings 2c, 2e and 2g are respectively connected to the upper strainer 23b. 5b and 6b, and the couplings 2d, 2f and 2h communicate with the lower strainers 23c, 5c and 6c, respectively.

  3, the resin regeneration apparatus 3 is provided with a support frame base 31 corresponding to a part of the support frame base 21, and couplings 2c, 2d, 2e,... Of the activated carbon unit 23, the cation exchange unit 5 and the anion exchange unit 6. .. Are provided, and the activated carbon unit 23, the cation exchange unit 5 and the anion exchange unit 6 are attached in a removable manner. A cleaning water tank 32, an acid regenerant tank 33, a salt regenerant tank 34, and an alkali regenerator tank 35 are provided opposite to the support frame 31, and are connected via lines L16, L17,. Are connected to the couplings 4c, 4d, 4e,. Electric conductivity meters 3d, 3e, and 3f are provided on the lines L22, L26, and L31, and are input to the control device 36.

  The regenerative drainage treatment apparatus 4 is composed of a mixed storage tank 41, a pH adjustment tank 42, and a biological treatment tank 43 that communicate with the line L15. The mixing storage tank 41 is configured to introduce the regenerated drainage liquid of each unit, mix and store it. The pH adjusting tank 42 is configured to adjust the pH by injecting a pH adjusting agent from the line L34 into the mixed solution sent from the mixed storage tank 41. The biological treatment tank 43 is composed of an activated sludge treatment tank, and is configured to return the activated sludge from the line L36 to perform aerobic biological treatment, discharge the treated water from the line L37, and discharge excess sludge from the line L38. Yes. 2, V, V1, V2, V3... Are valves.

  In the gas refining process, acid gas is introduced into the absorption tower 11 from the oil refining and other processes as the absorption process through the line L3, and is contacted with the lean amine liquid entering from the line L2 in the packed bed 15, thereby absorbing and removing the acid component. The purified gas is returned from the line L4 to the process, and the resulting rich amine liquid is sent from the line L1 to the regeneration tower 12. Here, fusible gases such as hydrogen sulfide and carbon dioxide that form thermally decomposable amine salts are also difficult to breathe such as formic acid, acetic acid, oxalic acid, thiocyanic acid, thiosulfuric acid, and inorganic acids that form HSAS. Are also absorbed to form thermally decomposable and thermally stable amine salts.

  In the primary regeneration step, steam generated by the reboiler 17 is introduced and heated in the regeneration tower 12 to steam strip the rich amine liquid entering from the line L1, and heat such as hydrogen sulfide and an amine salt of carbon dioxide gas. The decomposable amine salt is decomposed to release an acid component, and the amine is primarily regenerated to produce a lean amine solution, which is circulated from the line L2 to the absorption tower 11. The separated acidic gas such as hydrogen sulfide and carbon dioxide gas is released from the system through the line L6. However, non-aeration gases such as formic acid, acetic acid, oxalic acid, thiocyanic acid, thiosulfuric acid and other inorganic acids are used. HSAS such as the amine salt of the acid component is not decomposed and accumulates in the amine solution. The alkali is injected into the line L2 from the line L10 through the valve V to neutralize the lean amine solution, and the neutralized lean amine solution is circulated to the absorption tower 11.

  A part of the lean amine solution is diverted from the line L8 and sent to the ion exchange device 2 for secondary regeneration. The ion exchange device 2 is coupled to the couplings 1a, 1b, 1c,... Of the support frame 21 by coupling the mechanical filter unit 22, the activated carbon unit 23, the cation exchange unit 5, and the anion exchange unit 6 with 2a, 2b, 2c,. ... are attached and attached. Then, the lean amine solution entering from the line L8 is flowed in series, filtered by the mechanical filter unit 22, treated with activated carbon by the activated carbon unit 23, and exchanged and removed by the cation exchange resin layer 5a by the cation exchange unit 5, and by the anion exchange unit 6. The anions constituting the HSAS are exchanged and removed by the anion exchange resin layer 6a to perform secondary regeneration. The secondary regenerated amine liquid (lean amine liquid) is circulated from the line L9 to the absorption tower 11.

  The electrical conductivity signals of the electrical conductivity meters 3a, 3b, and 3c are input to the control device 24, determine the through-flow point where ions leak from the cation exchange unit 5 and the anion exchange unit 6, and issue a unit exchange signal. At this time, when the electrical conductivity of the effluent suddenly increases, that is, when the cumulative flow rate of the lean amine solution at the flow-through point where ions start to leak is 100%, the cumulative flow rate of the lean amine solution is The liquid passing is stopped at a point of time of 103 to 106%, preferably 104 to 105%, and a unit exchange signal is issued to regenerate the cation exchange resin layer. Even in this case, the anion exchange unit 6 stops the flow of liquid at the point where the electrical conductivity of the effluent suddenly increases, that is, the flow-through point where ions start to leak, and signals the unit exchange so as to regenerate the anion exchange resin layer. To emit. In response to such a unit exchange signal, the saturated unit is removed and replaced, and the removed unit is sent to the purification center for reproduction.

  In the resin recycling apparatus 3, couplings 2c, 2d, 2e,... Of the activated carbon unit 23, the cation exchange unit 5, and the anion exchange unit 6 are joined to the couplings 4c, 4d, 4e,. The activated carbon layer 23a, the cation exchange resin layer 5a, and the anion exchange resin layer 6a are regenerated. The regeneration of the activated carbon unit 23 is activated by sending washing water from the washing water tank 32 and sending heated gas, steam or the like from another path. The regeneration of the cation exchange unit 5 is carried out by washing water from the washing water tank 32 and backwashing, sending acid regenerating agent from the acid regenerating agent tank 33, performing chemical injection and extrusion, and sending washing water from the washing water tank 32 and washing. Then play it. Regeneration of the anion exchange unit 6 is carried out by washing water from the washing water tank 32 and backwashing, sending a salt regenerating agent from the salt regenerating agent tank 34, and sending an alkali regenerating agent from the alkali regenerating agent tank 35, and performing chemical injection and extrusion. The cleaning water is sent from the cleaning water tank 32 to be cleaned and regenerated. After regeneration, the units 23, 5 and 6 are sent to the ion exchange device 2 to prepare for replacement.

  The regeneration drainage generated during the regeneration of each unit in the resin regeneration unit 3 is introduced into the regeneration drainage treatment unit 4 from the line L15, and the regeneration drainage is processed. The regeneration drainage introduced from the line L15 is mixed and stored by introducing the regeneration drainage of each unit into the mixing reservoir 41. Here, the acidic effluent and the alkaline effluent are mixed and neutralized. Further, in the pH adjustment tank 42, the pH is adjusted by injecting a pH adjusting agent from the line L 34 into the mixed solution sent from the line L 33, and introduced into the biological treatment tank 43 from the line L 35. In the biological treatment tank 43, the activated sludge in the tank is pulled out from the line L36 and returned, and aerobic biological treatment is performed using the activated sludge. The treatment liquid is discharged from the line L37, and excess sludge is drawn from the line L38.

  In the resin regeneration apparatus 3, since the regeneration waste liquid can be continuously supplied, the biological activity of the activated sludge in the regeneration waste liquid treatment apparatus 4 can be maintained, and the treatment can be performed efficiently and stably. Can do. The above regeneration drainage treatment is an example of biological treatment, but regeneration drainage treatment may be performed by oxidant oxidation treatment or other treatment, and even in this case, regeneration drainage can be continuously supplied. , Can process stably.

  As the activated carbon unit 23, the cation exchange unit 5, and the anion exchange unit 6, three columns having an inner diameter of 10 mm and a height of 700 mm were used. The activated carbon unit 23 was filled with 55 mL of coal-based crushed coal (Crycol WG-560: trademark of Kurita Kogyo Co., Ltd.) as activated carbon. The cation exchange unit 5 is filled with 55 mL of a strongly acidic cation exchange resin (total exchange capacity 1.91 meq / mL-resin, neutral salt decomposition capacity 1.90 meq / mL-resin) which is a used resin of the ultrapure water production apparatus. Thus, the cation exchange resin layer 5a was formed. The anion exchange unit 6 is 55 mL of strongly basic anion exchange resin (total exchange capacity 1.10 meq / mL-resin, neutral salt decomposition capacity 1.06 meq / mL-resin), which is a used resin of the ultrapure water production apparatus. Filled to form an anion exchange resin layer 6a. Methyldiethanolamine (amine concentration 38.6% by weight, HSAS concentration 1.51% by weight) that absorbed acid gas and was primarily regenerated by vapor stripping was added to the ion exchange device 2 equipped with these units at SV3.8. As a result, an amine solution having an amine concentration of 40.1% by weight and an HSAS concentration of 0% by weight was obtained.

  When the anion exchange unit 6 is saturated, a 10% by weight potassium chloride aqueous solution is passed through 8 eq / L-resin at a water flow rate of SV15, and then a 4% by weight sodium hydroxide aqueous solution is passed through 10 eq / L-resin through a water flow. The liquid was passed at a speed SV15. Thereafter, pure water was passed through 5 volumes of the resin, washed and regenerated. The regeneration drainage was pH: neutral, CODmn: 1250 mg / L, BOD: 1180 mg / L.

  The mixed waste liquid (CODmn: 144 mg / L, BOD: 128 mg / L) obtained by mixing 1 part by weight of the regenerated waste liquid with 9 parts by weight of the water to be treated of the activated sludge treatment apparatus for organic wastewater by the activated sludge treatment apparatus. When the aerobic biological treatment was performed, treated water with CODmn: 47.5 mg / L and BOD: 9.8 mg / L was obtained.

  The treatment liquid obtained by oxidizing the regenerated waste liquid with a hydrogen peroxide-based oxidizing agent was CODmn: 188 mg / L, and the treatment liquid obtained by further treating with activated carbon was CODmn: 132 mg / L. Further, the treatment liquid obtained by oxidizing the regenerated waste liquid with a chlorine-based oxidizing agent was CODmn: 238 mg / L, and the treatment liquid obtained by further treating with activated carbon was CODmn: 181 mg / L.

  Diisopropanolamine (amine concentration 40.9% by weight, HSAS concentration 1.33% by weight) which absorbed acid gas and was primarily regenerated by steam regeneration in the same apparatus as in Example 1 (but omitting the anion exchange unit) , Potassium ion concentration 6700 mg / L, total HSAS concentration 3.66 wt% corrected for the amount neutralized by potassium) was passed through SV3.8, and new strong acid cation exchange resin and used strong acid The adsorption capacities of cation exchange resins (total exchange capacity 1.91 meq / mL-resin, neutral salt decomposition capacity 1.90 meq / mL-resin) were compared. The results are shown in Table 1.

  The results in Table 1 show that the amount of saturation with respect to the potassium ion concentration in the diisopropanolamine passed through for the exchange capacity of each of the new strong acid cation exchange resin and the used strong acid cation exchange resin (at the flow-through point). In order to check the electrical conductivity of the treatment liquid at the time of the actual total flow rate ratio when the total flow rate) is 100%, and the adsorption amount of diisopropanolamine in that state, it is regenerated with sulfuric acid and purified water It shows the value of the total nitrogen concentration in the regenerated effluent washed with Regeneration of the cation exchange resin was performed by passing 8 wt% sulfuric acid 5 BV and pure water 3 BV through SV8.3.

  From the results in Table 1, it can be seen that there is no difference in the amount of amine adsorption between the new resin and the used resin, and the used resin can be used for this application without any problem. In Table 1, as the flow rate increases, the total nitrogen concentration in the regenerated effluent decreases significantly. This is because the diisopropanolamine has passed through the cation exchange unit and has undergone protonation. It has been shown that isopropanolamine itself is initially adsorbed on the cation exchange resin, which is exchanged and desorbed to a strong affinity potassium ion by the cation exchange resin. This indicates that the leakage of diisopropanolamine into the regenerated effluent can be reduced by flowing diisopropanolamine containing potassium ions to the full capacity.

  The treatment liquid of Example 2 (treatment liquid when 105% of the exchange capacity of the cation exchange resin was passed) was passed through the same anion exchange unit as in Example 1 with SV 3.8, and the electric conductivity was determined. The through-flow point was detected and the adsorption capacities of the new anion exchange resin and the used anion exchange resin were compared. The results are shown in Table 2.

  From the results in Table 2, it can be seen that residual HSAS in the treatment liquid is not detected for both the new resin and the used resin, and the used resin can be used for this application without any problem. The same effect can be obtained in the case of the treatment liquid when the cation exchange resin is exchanged up to 100%, but in both cases, the through point can be easily detected by the electric conductivity.

  In the refining process of acid gas generated in petroleum refining and other processes, the amine liquid that absorbs the acid component and accumulates heat-stable amine salt (HSAS) is regenerated using ion-exchange resin, and heat-stable amine salt It can be used in a method for efficiently removing the acid component.

  1: Gas purification device, 2: Ion exchange device, 3: Resin regeneration device, 4: Regeneration drainage treatment device, 5: Cation exchange unit, 6: Anion exchange unit, 1a, 1b, 2a, 2b,. 4c, 4d, ...: Coupling, 3a, 3b, 3c, 3d, 3e, 3f: Conductivity meter, 5a: Cation exchange resin layer, 6a: Anion exchange resin layer, 11: Absorption tower, 12: Regeneration tower 13, 14: Heat exchanger, 15, 16: Packing layer, 17: Reboiler, 21, 31: Support frame base, 22: Mechanical filter unit, 23: Activated carbon unit, 23a: Activated carbon layer, 24, 36: Control device 32: Washing water tank, 33: Acid regenerant tank, 34: Salt regenerant tank, 35: Alkaline regenerant tank, 41: Mixed storage tank, 42: pH adjustment tank, 43: Biological treatment tank.

Claims (4)

An absorption step in which an acidic gas containing an acid component is contacted with an amine liquid in an absorption tower to absorb and remove the acid component to produce a rich amine liquid;
An amine primary regeneration step in which a rich amine liquid that has absorbed an acid component is thermally decomposed in a regeneration tower to release a diffusive acidic gas, thereby producing a lean amine liquid by primary regeneration of the rich amine liquid;
By neutralizing the lean amine solution with an alkali, the accumulated heat-stable lean amine salt is decomposed to release a salt of a weakly diffusible weak acid, and the amine solution is neutralized by circulating the lean amine solution to the absorption tower; ,
A part of the lean amine liquid is passed through the cation exchange resin layer and the anion exchange resin layer, and the cation contained in the lean amine liquid and the anion constituting the heat-stable amine salt are exchanged and adsorbed to regenerate and absorb the lean amine liquid. A method comprising an amine secondary regeneration step that is circulated through the tower,
Strongly acidic cation exchange resin and strong basic anion exchange resin used for the removal of neutral salt as cation exchange resin layer and anion exchange resin layer in amine secondary regeneration step, total exchange capacity and neutral salt decomposition capacity An amine solution characterized by using a cation exchange resin layer filled with a used cation exchange resin having a reduced amount and an anion exchange resin layer filled with a used anion exchange resin having a reduced total exchange capacity and neutral salt decomposition capacity How to play.   When the flow rate of the lean amine liquid at the flow-through point of the cation exchange resin layer is 100%, the cation exchange resin layer is regenerated when the flow rate of the lean amine liquid reaches 103 to 106%, and the anion exchange resin layer The method according to claim 1, wherein the anion exchange resin layer is regenerated at the flow-through point. As the cation exchange resin layer and the anion exchange resin layer, an ion exchange apparatus including a detachable exchange type cation exchange unit and an anion exchange unit filled with a used cation exchange resin and a used anion exchange resin is provided,
The cation exchange unit filled with the regenerated cation exchange resin and the anion exchange unit filled with the regenerated anion exchange resin are attached to the ion exchange apparatus, and the cation and heat contained in the lean amine liquid are passed through the lean amine liquid. Adsorption and removal of anions constituting the stable amine salt to regenerate the amine solution,
The cation exchange unit adsorbing cations and anions and the anion exchange unit are desorbed from the ion exchange device and replaced with a cation exchange unit filled with a regenerated cation exchange resin and an anion exchange unit filled with a regenerated anion exchange resin. And
The method according to claim 1 or 2, wherein the secondary regeneration of the amine liquid is continued. Desorbing the cation exchange unit and anion exchange unit adsorbing cations and anions from the ion exchange device,
The method according to claim 3, wherein the desorbed cation exchange resin of the cation exchange unit and the anion exchange resin of the anion exchange unit are regenerated by a resin regenerator.

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