JPH0411921A - Method for removing deteriorated material from refining liquid adsorbent - Google Patents

Abstract

PURPOSE:To prevent the deterioration of a liq. adsorbent by providing a bypass line to the circulating line for the adsorbent, filtering the adsorbent with a mechanical filter and an activated-carbon filter and backwashing the bypass line when a definite adsorption state is reached. CONSTITUTION:A refining liq. adsorbent is continuously circulated between an adsorption system and a regeneration system, and the impurities in the raw material adsorbed in the adsorption system are separated to remove the deteriorated material in the adsorbent. Concretely, a part of the adsorbent is bypassed into a bypass line provided to the adsorbent circulating line and successively filtered by the mechanical filter and activated-carbon filter to remove the deteriorated material. When a definite adsorption state is reached in the mechanical filter, the bypass line is isolated from the circulating line. A cleaning fluid is introduced from the downstream side of the mechanical filter and discharged from the upstream side to backwash the mechanical filter. By this method, the efficiency in removing the deteriorated material in the adsorbent is kept high over a long period, and the deterioration of adsorbent is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for removing degraded substances from an adsorbent for refining, and can be used in an adsorption cleaning type impurity removal process in an oil refining plant or the like.

[Background technology]

Conventionally, in petroleum refining plants, etc., impurity removal using an adsorption cleaning method using an amine-based refining adsorption liquid has been used to purify sour gas containing hydrogen sulfide, carbon dioxide, etc., and light hydrocarbons such as LPG. It is being done.

Adsorption cleaning purification involves an adsorption system that purifies the raw material by adsorbing impurities to the adsorbent, a regeneration system that separates and discharges impurities from the adsorbent, and a circulation path that circulates the adsorbent between the two systems. , a continuous adsorption regeneration process using circulating adsorption liquid is performed.

Here, the regeneration system is often shared by multiple adsorption systems, and for example, a large number of adsorption systems for purifying LPG, HPGAS, LPGAS, etc. are each connected to one regeneration system via a circulation path, and the regeneration system from each is connected. A method in which the adsorbent is treated in the same regeneration system is often used.

On the other hand, in adsorption-washing purification, corrosion-causing substances such as amine deterioration products and heat-stable salts are generated in the adsorbent during repeated circulation, which may have an adverse effect on the processing system. Therefore, it is necessary to remove degraded substances in the adsorbent as appropriate.
For example, in a reclaimer, soda ash, caustic soda, etc. are added to turn degraded materials into sludge, and then the adsorbent is separated by distillation and the residual content is discharged outside the system, or an activated carbon filter, etc. placed in the circulation path of the adsorbent is used. A method of adsorbing and removing degraded substances using the filtration means used is adopted.

[Problem to be solved by the invention]

By the way, in the above-mentioned filtration means, as the activated carbon filter is used, the amount of degraded substances adsorbed on the activated carbon filter increases, and the resistance to the adsorbing liquid increases, and the adsorption performance decreases.

To deal with this, a mechanical filter or the like is placed upstream of the activated carbon filter in the circulation path to filter relatively coarse impurity particles in the adsorption liquid in advance, so that the activated carbon filter only needs to adsorb fine particles to reduce the load. Attempts are being made to reduce it.

However, if the mesh of a mechanical filter or the like is made coarse, filtration cannot be performed effectively and deterioration of the adsorbent cannot be sufficiently prevented. On the other hand, if the mesh is made finer, it is more likely to become clogged, and cleaning and other operations will need to be carried out frequently.

In particular, cleaning a mechanical filter requires complicated operations such as opening it from the circulation path, cleaning it, and restoring it. Also,
During cleaning, the adsorbent remaining in the mechanical filter is discharged together with impurity particles and is wasted.

Furthermore, if air or the like remains in the mechanical filter during restoration, air or the like will enter the circulation path when the process is restarted, oxidizing the adsorbent and causing overall deterioration. For these reasons, it has been difficult to implement preliminary filtration using a mechanical filter or the like.

An object of the present invention is to provide a method for removing degraded substances from a refining adsorption liquid that can efficiently remove degraded substances, prevent deterioration of the adsorption liquid, and facilitate maintenance and other operations.

[Means to solve the problem]

The present invention provides continuous circulation between the adsorption system and the regeneration system,
In order to remove impurities in the raw material adsorbed by the adsorption system using regenerated fibers, the first method is to remove the impurities from the adsorption solution in a bypass path provided in the circulation path of the adsorption solution. The adsorbed liquid passing through the bypass route is filtered sequentially through a mechanical filter and an activated carbon filter to remove degraded substances, and when the mechanical filter reaches a certain adsorption state, the adsorbed liquid is circulated through the bypass route. This method adopts the steps of blocking the mechanical filter from the mechanical filter, introducing cleaning fluid from the downstream side of the mechanical filter, and discharging it from the upstream side to perform reverse cleaning.

In addition, as a second method, before the reverse washing of the first method, the adsorbent solvent is introduced from the upstream side of the mechanical filter, passed through an activated carbon filter, and then collected into the circulation path. It is.

Furthermore, as a third method, after the reverse cleaning in the first or second method, the adsorbent solvent is introduced from the upstream side of the mechanical filter and exhausted from the downstream side to perform scavenging. .

[For production]

In such the present invention, by the first method,
The adsorbent is filtered by a mechanical filter and an activated carbon filter while passing through the bypass path, and degraded substances in the adsorbent are successively adsorbed and removed.

Here, by arranging the mechanical filter and the activated carbon filter in the bypass path, they can be appropriately separated from the circulation path, and it is possible to perform work such as cleaning each filter regardless of the normal purification process in the circulation path.

For mechanical filters, by automatically performing reverse cleaning according to the adsorption state, maintenance work is easier compared to conventional manual cleaning, and there is no problem even if it is performed frequently. Therefore, it becomes possible to use a fine mesh in a mechanical filter, which improves the pre-adsorption performance and extends the life of the activated carbon filter.

Furthermore, according to the second method, by cleaning the mechanical filter and the activated carbon filter with the adsorbent solvent before reverse cleaning, it becomes possible to collect the adsorbent remaining in each filter part into the circulation path, Even when cleaning is performed frequently, it is possible to reduce wastage of adsorbent liquid.

Then, by using the second method, by performing air scavenging with the adsorbent solvent after reverse cleaning, it becomes possible to eliminate air remaining in the mechanical filter part during cleaning, and connect it to the circulation path again. At the same time, it becomes possible to prevent oxidation of the adsorbent in the circulation path.

The present invention achieves the above objects by reliably and efficiently removing degraded substances from the adsorbent, and by facilitating maintenance and other operations.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

The processing system 1 shown in FIG. 1 purifies raw materials such as sour dregs and LPG by removing impurities such as hydrogen sulfide, and includes an adsorption system 10 and a regenerated yarn 20.

The adsorption system IO adsorbs and cleans impurities in the raw material using an internal amine-based adsorption liquid, and is connected to a raw material inlet pipe 11 and a purified raw material outlet pipe 12.

The regeneration system 20 is a system into which the adsorbent used in the adsorption system 10 is continuously introduced, and the impurities in the adsorbent are separated and discharged for regeneration. It is connected to the adsorption system 10 via a path 30.

The circulation path 30 runs from the adsorption liquid outlet of the adsorption system IO to the regeneration system 2.
0, and a return pipe 32 from the adsorption liquid outlet of the regeneration system 20 to the adsorption liquid inlet of the adsorption system 10. A heat exchanger 33 is installed between these sending pipes 31 and return pipes 32 to reduce heat loss in each prefecture 10.20. Further, a flow rate regulating valve 34 is disposed in the feed pipe 31, and the circulation path 30 is passed through each prefecture 10.
The flow rate of the adsorption liquid circulated between the two is adjusted.

Here, in the circulation path 30, a filtration means 40 is installed between the outlet side of the regenerated yarn 20 and the heat exchanger 33 for removing amine deterioration products generated in the adsorbent.

The filtration means 40 is located at two branch points Sl of the circulation path 30.

It has a bypass path 41 connecting S2, and a part (2 to 20%) of the adsorbent passing through the circulation path 30 can be
degree) is branched into a bypass path 41 and flown. A mechanical filter 43 and an activated carbon filter 44 are arranged in series in the bypass path 41 . Among these, the mechanical filter 43 has a fine mesh (about 5 to 40 μm).
This filter reduces the load on the activated carbon filter 44 by filtering out relatively large particles of degraded substances in the adsorption liquid passing through. Further, the activated carbon filter 44 adsorbs and removes fine particles of degraded substances in the adsorption liquid passing therethrough.

Further, the filtration means 40 is provided with a deterioration material removal means 50 for removing deterioration materials filtered by the mechanical filter 43.

As shown in FIG. 2, the degraded product removing means 50 is composed of an ascending pipe or a pipe connected to the bypass path 41, a cleaning fluid supply means 60, a control means 70 for controlling these, and the like. be.

An inlet-side cutoff valve 51 is arranged on the upstream side of the mechanical filter 43 in the bypass path 41, and a backwash drain pipe 52A is connected between the cutoff valve 51 and the filter 43. The backwash drain pipe 52 is connected to an external waste liquid tank or the like via a backwash drain valve 52, and a law-compliant introduction pipe 6 is connected between the backwash drain valve 52 and the bypass path 41.
1A is connected.

The legal introduction pipe 618 is connected to an external water supply source via the legal introduction valve 61. Here, the water supplied to the law-compliant introduction pipe 61A is a solvent for the amine-based adsorption liquid, and has been degassed in advance.

An outlet-side cutoff valve 53 is disposed on the outlet side of the mechanical filter 43 in the bypass path 41 between it and the activated carbon filter 44, and a backwash introduction pipe 62A is connected between the cutoff valve 53 and the filter 43. .

The backwash introduction pipe 62A is connected to a backwash fluid mixing tank 63 via a backwash introduction valve 62. Backwash fluid mixing tank 6
3 is connected to a nitrogen gas supply pipe 64A and a water supply pipe 65A, and the nitrogen gas supply pipe 64A is connected to an external nitrogen gas (N2) supply source via a nitrogen gas supply valve 64, and the water supply pipe 65A is connected to the nitrogen gas supply pipe 64A. is connected to the same water supply source as the legal introduction pipe 61A via a water supply valve 65. Further, an air bleed pipe 66A that is opened to the outside is connected to the backwash fluid mixing tank 63 via an air bleed valve 66, and a mixing pipe 67A that is connected to the backwash introduction pipe 62A via a mixing valve 67. is connected, and by opening the mixing valve 67, the nitrogen gas and water in the backwash fluid mixing tank 63 are mixed and sent in a foamed state to the backwash introduction pipe 62A.

Each of these pipe lines 61A...67A, multi-valve 61...6
7 and a mixing tank 63 for supplying cleaning fluid 6
0 is configured.

On the other hand, the aforementioned multiple valves 51...53, 61...67 are each connected to the sequencer 71. Further, a flow meter 72 is disposed in the middle of the legal introduction pipe 61A, a differential pressure gauge 73 is installed in the mechanical filter 43 to detect the pressure difference between the inlet side and the outlet side, and the backwash fluid mixing tank 63 is disposed in the mechanical filter 43.
A level meter 74 is installed to detect the internal liquid level, and each output is input to a sequencer 71.

The sequencer 71 has a built-in timer and each meter 72 to 74.
Refer to the output of the preset time chart (third
(see figure), the control means 70 is switched by these sequencers 71, etc.
or configured.

Next, the processing procedure in this embodiment will be explained.

Normally, the sequencer 71 sets the degraded product removing means 50 to a filtering state, and the filtering means 40 filters degraded products from the circulating adsorption liquid.

In the filtration process, as shown on the left side from time T1 in FIG. 3, the sequencer 71 opens the inlet-side shutoff valve 51 and the outlet-side stage valve 53, and closes all other ascending valves. As a result, as shown in FIG.
1 is the branch point S1. S2 is connected, and circulation route 3
A part of the adsorbent from 0 is bypassed and filtered by the mechanical filter 43 and activated carbon filter 44 .

Here, when the differential pressure gauge 73 detects that the differential pressure in the mechanical filter 43 has become higher than a preset reference value, the sequencer 71 sets the degraded product removing means 50 to a law-compliant processing state, and the filtering means 40 bypass routes 4
Collect the adsorbent remaining in step 1.

In the compliance process, as shown between times T+-72 in FIG. 3, the sequencer 71 closes the inlet-side shutoff valve 51 and opens the compliance introduction valve 61.

Note that the outlet-side shutoff valve 53 remains open.

As a result, as shown in FIG. 5, the bypass path 41 is blocked on the branch point St side, and water from the law-compliant introduction pipe 61A is introduced instead. The adsorbed liquid remaining on the mechanical filter 43, activated carbon filter 44, etc. is dissolved by this water, and is collected along with the water through the bypass path 41 from the branch point S2 to the circulation path 30.

Here, when it is detected by the flow meter 72 that the amount of water has reached a preset value, the sequencer 71 sets the degraded product removal means 50 to a backwash processing state, and the filtration means 40
The mechanical filter 43 is cleaned by removing filtrate.

In the backwashing process, time T2 to T in FIG.

As shown in between, the sequencer 71 closes the outlet-side shutoff valve 53 and the compliance introduction valve 61, and opens the backwash drain valve 52. Then, based on the built-in timer, the water supply valve 65 and the air vent valve 66 are opened for a certain period of time, and water is supplied to the backwash fluid mixing tank 63 until the level meter 74 reaches a preset value or more.

Subsequently, the nitrogen gas supply valve 64 is opened for a certain period of time, and nitrogen gas is supplied into the backwash fluid mixing tank 63.
During this time, the mixing valve 67 and the backwash introduction valve 62 are opened for a certain period of time. As a result, as shown in FIG. 6, a foamed backwash fluid containing a mixture of water and nitrogen gas is sent to the backwash introduction pipe 62A, and the bypass path 41 is supplied from the downstream side to the upstream side of the mechanical filter 43. Backwash fluid in a foamed state is distributed toward.

This backwash fluid flushes out degraded substances that have been filtered out by the mechanical filter 43, and the backwash drain pipe 52A
is discharged through the

Note that these backwash operations are repeated three times during the backwash process, and during the third operation, the backwash introduction valve 62 is maintained in an open state. Furthermore, when supplying water for the -th time, the sequencer 71 checks the level meter 74, and supplies water only when the level is less than the set value, otherwise omitting the supply of water.

When these backwashing processes are completed, the sequencer 71 sets the degraded product removing means 50 to a scavenging state, and removes the gas introduced into the filtration means 40 together with the backwashing fluid during the backwashing process.

In the scavenging process, as shown between time 13 and time 14 in FIG. The drain valve 66 is opened.

As a result, as shown in FIG. 7, the backwash drain pipe 52A
Water is introduced from the compliant introduction pipe 61A, passes through the bypass path 41 and the mechanical filter 43, and is sent to the backwash fluid mixing tank 63 from the backwash introduction pipe 62A. This water scavenges the bypass path 41 and mechanical filter 43, and removes air and the like remaining from the previous backwashing process.

Then, when a certain period of time has elapsed since the flowmeter 72 detected that the amount of water had reached a preset value or a legal amount,
The sequencer 71 opens the inlet-side shutoff valve 51 and the outlet-side stage valve 53, and closes all other ascending valves. As a result, the degraded substance removing means 50 is restored to the filtering state shown in FIG. 4 again, and the adsorbent passing through the bypass path 41 is filtered by the mechanical filter 43 and the activated carbon filter 44.

According to this embodiment, the following effects can be obtained.

That is, since the filtration means 40 is provided with the degraded substance removal means 50 that performs the treatment based on the present invention, the degree of contamination of the mechanical filter 43 is monitored, and when the contamination becomes severe, cleaning processing is automatically executed. , the function of the mechanical filter 43 can be restored.

Therefore, it is possible to eliminate the need for manual work due to dirt on the mechanical filter 43, and the maintenance of the filtration means 40 can be easily performed, and even if a fine mesh is used, inconveniences such as complicated work will not occur. There is no.

Therefore, a finer mesh can be used for the mechanical filter 43, which can improve filtration performance, reduce the load on the activated carbon filter 44, and extend its life.

On the other hand, when recovering the function of the mechanical filter 43, the cleaning effect can be enhanced by basically employing backwashing processing and using a foamed fluid made by mixing nitrogen gas with water.

In addition, since it was decided that legal compliance treatment would be carried out prior to backwashing treatment,
The adsorbent remaining in the mechanical filter 43 or the activated carbon filter 44 can be collected into the circulation path 30 by using water as a solvent for the amine-based adsorbent. Therefore, inconveniences such as the adsorption liquid being lost and wasted during the backwashing process can be avoided.

Furthermore, since backwashing is followed by scavenging,
Even if air or the like is introduced together with the backwash fluid and remains in the mechanical filter 43 or the like, it can be reliably removed. Therefore, it is possible to avoid inconveniences such as air or the like entering the circulation path 30 when the normal a-overtreatment is resumed, and the adsorbent being oxidized and deteriorating further.

Further, since the filtering means 40 is configured in a bypass path 41 branched from the circulation path 30, processing such as cleaning can be performed only on the bypass path 41 side. Therefore, circulation of the adsorbent can be maintained even during processing such as washing, and continuous purification processing in the adsorption system 10 and regenerated yarn 20 is not hindered, and work efficiency can be maintained at a high level. can.

Note that the present invention is not limited to the above embodiments,
It also includes the following modifications.

That is, the fluid used for backwashing is not limited to a mixture of water and nitrogen gas and foamed, but other inert gases such as helium gas may also be used. Furthermore, foaming is not essential and only water may be used, but foaming can enhance the cleaning effect. moreover,
The cleaning liquid is not limited to water, but it is preferable to use a liquid that can serve as a solvent for the adsorbent, taking into consideration its affinity with the adsorbent upon return.

Furthermore, as for the fluid used in the sequential processing, it is desirable to use a liquid that can serve as a solvent for the adsorption liquid.

Furthermore, the sequential processing may not be performed up to the activated carbon filter 44, but only within the range where the subsequent backwashing processing is performed. Note that sequential processing is not essential to the present invention and may be omitted as appropriate.

Furthermore, the scavenging process is not limited to using the legal process route and the backwash process route, but may also utilize separate dedicated piping or the like. At this time, the fluid used for the scavenging process is preferably a liquid that can serve as a solvent for the adsorption liquid, or the adsorption liquid itself may be used. Note that the scavenging process is not essential to the present invention and may be omitted as appropriate.

On the other hand, in the above-mentioned embodiment, the process was performed according to the procedure shown in FIG. 3, but the detailed timing settings etc. may be changed as appropriate during implementation. The number of repetitions, etc. may be set arbitrarily.

Further, in the embodiment described above, the processing was controlled by the control means 70 centered on the sequencer 71, but the specific configuration thereof, the state quantities to be referred to, etc. may be set as appropriate during implementation. For example, the degree of contamination of the mechanical filter 43 may not be determined by detecting the differential pressure, but may be determined by comparing the state of contaminated substances before and after, or by optically inspecting the state of clogging of the mechanical filter 43.

Furthermore, the piping configuration, valve arrangement, etc. of the deteriorating product removing means 50 are not limited to those in the above embodiments, and may be changed as appropriate in implementation so that backwashing, compliance, scavenging, etc. employed as the cleaning process can be performed.

Furthermore, the degraded product removing means 50 is not limited to the filtration means 40 and the treatment system 1 as in the embodiment described above, but can be applied to various other filtration means. Further, the means for realizing the method of the present invention is limited to the deteriorated product removing means 50 of the above-mentioned embodiment, and may be appropriately designed for implementation.

[Effects of the Invention] As described above, according to the present invention, since the mechanical filter can be automatically cleaned, the removal performance of the degraded substances of the adsorbent can be maintained at a high level over a long period of time, and the deterioration of the adsorbent can be prevented. This also makes maintenance work extremely easy.

[Brief explanation of the drawing]

Fig. 1 is a piping diagram showing the overall configuration of an embodiment of the present invention, Fig. 2 is a piping diagram showing the main parts of the embodiment, Fig. 3 is a time chart showing the processing in the embodiment, and Fig. 4. or seventh
Each figure is a piping diagram showing the flow of each process in the same embodiment. DESCRIPTION OF SYMBOLS 10... Adsorption system, 20... Regeneration system, 30... Circulation route, 40... Filtration means, 41... Bypass route,
43... Mechanical filter, 44... Activated carbon filter, 50... Degraded product removal means, 51... Inlet side shutoff valve, 52. 52A... Backwash drain valve and backwash drain pipe, 53... ... Outlet side shutoff valve, 60... Cleaning fluid supply means, 61.61A... Law-compliant introduction valve and law-compliant introduction pipe, 62.62A... Backwash introduction valve and backwash introduction pipe, 70... Control means. Applicant Idemitsu Engineering Co., Ltd. Agent Patent Attorney Sanzo Kinoshita (two others) - Figure '4 Figure 6? difference.

Claims (3)

[Claims] (1) A method for removing degraded substances from a refining adsorbent, which is continuously circulated between an adsorption system and a regeneration system, and the regeneration system separates impurities in the raw material adsorbed by the adsorption system, the method comprising: A part of the adsorbent is diverted to a bypass path provided in the circulation path, and the adsorbent passing through the bypass path is sequentially filtered with a mechanical filter and an activated carbon filter to remove degraded substances, and the mechanical filter maintains a constant adsorption state. Degraded products of the purification adsorption liquid characterized in that when the amount reaches the limit, the bypass path is cut off from the circulation path, the cleaning fluid is introduced from the downstream side of the mechanical filter, and the cleaning fluid is discharged from the upstream side to perform reverse cleaning. Removal method. (2) Claim 1 is characterized in that before the reverse washing, the adsorbent solvent is introduced from the upstream side of the mechanical filter, passed through an activated carbon filter, and then collected into the circulation path. A method for removing degraded substances from an adsorption solution for purification. (3) Claim 1 or 2, characterized in that after the reverse cleaning, an adsorption liquid solvent is introduced from the upstream side of the mechanical filter and discharged from the downstream side to perform scavenging. A method for removing degraded substances from an adsorption solution for purification.