JPS58128124A - Desorption of organic gas in carrier gas adsorbed by adsorbent - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for desorbing organic scum from a carrier gas by means of an adsorbent, as defined in the preamble of the claims.

When it comes to organic gases adsorbed from a carrier gas by an adsorbent, it is the solvent that causes the first *vcrx, or organic compounds that are relatively well adsorbed to the adsorbent or are difficult to desorb also have a short time *vcrx as well as the solvent. ! It becomes ivc. This maple dregs is written by H. Mentg rLl,,ft
reinh≪ng durch, Adsorp
-tion, Abso-rptiOn 1. Ind 0
xidation (air purification using adsorption, absorption, and oxidation)
Ifton-Verlag), page 112, Table 1.29) K is disclosed. The term organic gas used in the present invention is understood to include vapors of organic substances. Furthermore, the term adsorbent is intended to mean all adsorbents related to the technical field 1 relating to adsorbents, in particular activated carbon, zeolites and their equivalent substances.

When an adsorbable solvent is recovered using activated carbon, in order to regenerate the activated carbon that has adsorbed the solvent, an inert gas that is generated as a result of burning a fossil fuel (coal, etc.) is used to recover the adsorbed solvent. Either by heating and thereby washing away the desorbed solvent, or by blowing with steam, the mixture incidental to this regeneration, i.e. solvent vapor, and the above-mentioned inert material used for solvent recovery are removed. It is known that mixtures of gases or water vapor can be separated by known techniques to a purity that allows them to be used again.

The above regeneration operation is also called a heating regeneration method and consumes a relatively large amount of fuel. In order to expel these solvents from the activated carbon saturated with toluene or benzine, the amount of steam required is 8 times the recovery solvent (KtK).

The activated carbon must then be dried and cooled. Furthermore, in the case of a water-soluble solvent, it may be necessary to carry out such distillation to reduce its avr concentration. In addition, in the case of the thermal regeneration method (FIT H Atsox (AdsOX)) using a high-temperature inert gas at 200 to 600°C, the solvent 1111 is used to burn propane and generate a high-temperature inert gas.
Requires K4 or higher propane.

It is also known that, even in the area of the pressure change @ column method, adsorbed scum will be desorbed if the total pressure in the adsorption reactor is lowered. However, the organic gas that is the subject of τ here usually has a shape that is advantageous for adsorption or disadvantageous for desorption, such as the equilibrium crosstalk of the adsorbent (H-3untgsn, □ "Dust dust"). "Purification effect", J9
1976 rLIIFTj, Vol. 36, p. 28), without sparing a great deal of expense (without creating the necessary vacuum decomposition, a relatively large amount of solvent is not desorbed to the adsorbent). As a result, the amount of adsorption (additional amount) in the post-reading adsorption step is extremely small.Therefore, such a method is unattractive.Also, based on isomixture, 1 inert If regeneration is performed by capture by dregs f, the result will be unsatisfactory because of the high degree of dilution.

SUMMARY OF THE INVENTION The technical object of the present invention is to provide a method for desorbing organic sludge in a carrier sludge adsorbed onto an adsorbent that is more advantageous in terms of energy l than conventional regeneration methods.

This method pollutes the environment not only in terms of energy, but also in its implementation.

The above technical problem can be solved by a method engineer having the basic features set forth in claim 1.

Other configurations or aspects of the present invention are described in Claim 2.
It may be carried out based on the statements in the dependent claims below.

The cleaning gas in question according to the present invention can be used under desorption conditions, i.e. under conditions of 1 pressure or very low and 1 temperature or relatively high conditions, as opposed to the case where there is an adsorption amount of 1. As in the case, only a portion of the adsorbent is adsorbed by the adsorbent. does not function to exclude the desorbed organic gas from the stratified reactor.Moreover, regarding the desorption process, what is important in the present invention is the pressure at the time of desorption or the pressure at or below the pressure at the time of adsorption. This pressure difference should be approximately 50°C or more, and normally the larger the degree of vacuum, the larger the amount of scavenged debris that is absorbed by the adsorbent. If the severity is relatively small,
The residual amount of organic residue adsorbed by the adsorbent increases - (row (
result.

For the process according to the invention, it depends on whether the adsorption is carried out under pressure or at atmospheric pressure, whether the vacuum occurs suddenly or gradually at the beginning of the desorption, and whether the scavenging gas is Whether a constant or variable flow rate is used (this is not a matter of wisdom; these factors or conditions can be easily determined for each application and are particularly important for the organic matter being desorbed). It depends on whether the degree of dilution of the gas is at the limit value π or at the preferred value.

When the scavenging gas at issue here is adsorbed by an adsorbent, the released heat of adsorption causes a certain temperature rise. This amount of heat is primarily useful for desorption of adsorbed organic scum. This is because the desorption process is adsorption heat-based. Depending on the type and amount of scavenged debris to be adsorbed, the adsorbent may be further heated, which may facilitate the rate of desorption of organic debris.

Although carbon monoxide, carbon dioxide, and methane were mentioned above as particularly advantageous scavenging gases in connection with the present invention, other carbon or hydrocarbons having one carbon atom per molecule may also be used as scavenging gases. (Although, it is also suitable as
Various molecules with multiple carbon atoms may also have implications for desorption problems). In these cases, the decision to use a particular scavenging gas depends on whether the scavenging gas and the desorbed organic debris can be later separated, as well as whether the scavenging gas can be separated from the desorbed organic debris. It depends on whether or not it can be released into the atmosphere without further treatment after being separated from the debris. Regarding the latter problem, it can be said that it is particularly advantageous to use carbon dioxide as the scavenging gas.

After desorption has taken place and, if necessary, the adsorbent has been cooled again to the stratification temperature, the carrier gas passing through the adsorber is adsorbed onto the adsorbent in the original desorption phase, in conjunction with the adsorption of organic gases from the carrier gas. Removes cleaning debris adsorbed by the agent. In this case, there is no need for a fuel-intensive desorption step, as is the case when steam is used as the scavenging residue. The scavenging gas released at this time may be released into the atmosphere together with the carrier gas, or may be subjected to appropriate post-treatment to be removed from the carrier gas, depending on its amount and its harmfulness to the atmosphere. .

The method according to the invention is therefore particularly useful for cyclically alternating adsorption and desorption in order to separate a carrier gas stream from an organic gas and, if desired, to regenerate it.

In particular, when using the method of the invention for solvent recovery, the adsorption step can be carried out at approximately atmospheric pressure and the desorption can be carried out at pressures of approximately less than 0.5 bar, in particular less than 0.1 bar.

Furthermore, according to the invention, it is also possible to remove the desorbed organic gases from the scavenging gas exiting the reactor at a pressure higher than the pressure during desorption, in particular for the purpose of concentrating the recovered organic gases. It's advantageous. In this case, the aforementioned high pressure level M may be carried out by various known methods, such as by concentrating the desorbed organic gas.

The above steps are preferably carried out at pressure levels at or above the adsorption stage. If the adsorption pressure is atmospheric pressure, recovery of the desorbed organic gas can be carried out at pressures up to approximately 10 bar.

Furthermore, in the present invention, the reuse of the scavenging gas after separation of the desorbed organic gas does not require releasing this gas into the atmosphere, and ignoring some loss layer, the process It has the advantage that there is no need to continually replenish it. Furthermore, organic gases that are not completely separated from the scavenging gas are adsorbed onto the adsorbent again and separated again in a subsequent desorption step, so that they are not released into the atmosphere.

Other objects, features, effects, and various uses of the present invention will become apparent from the following description of embodiments based on the accompanying drawings. Hereinafter, the present invention will be specifically described based on embodiments shown in the drawings.

The carrier gas to be separated from the box gas is passed through the pipe (1
) through a gas supply valve (2) to a reactor (4) filled with adsorbent (3), and from the reactor (4) a gas discharge valve (5) and a pipe (6). It is released in a purified state. Once the organic gas to be adsorbed has been adsorbed on the adsorbent to the desired maximum (usually before the reactor outlet)
, the gas supply valve (2) of line (1) and the gas discharge valve (5) of line (6) are immediately closed and the flow of carrier gas is thereby interrupted or They operate alternately in parallel and are guided to adsorbers where desorption has already been completed.

V when the pressure during adsorption is (exceptionally) higher than the ambient pressure.
i. The reactor (4) is depressurized by operating the valve (5a) of the pipe line (6a) which branches off between the reactor and the gas discharge valve (5), but at this time, the pressure of the reactor (4) is reduced. is usually just a purified carrier gas.

To reduce the pressure in the reactor (4) to the desorption pressure (in countercurrent to the adsorption direction), use a vacuum pump (9) connected to the line (7) and close the valve (8). On the outlet side of this pump, the gas mixture sucked in via the line (7) is processed. At the same time, in the attachment and detachment direction,
As detailed below, a scavenging gas is passed through the reactor (4) at the desorption pressure. The entire aspirated gas mixture reaches a gas separation device (river), for example a condenser, via line αO. The desorbed gas is transferred from this device (Ill) in liquid form via line (12). This device (1
From 1), the scavenging gas remaining during the separation process is
It is discharged via conduit 1131. This conduit 113) is
It is connected to a line (I4) introducing fresh scavenging gas. Said line (141) is connected to the reactor (4) via a pressure regulating valve (15+) in the case of countercurrent scavenging. Fresh or make-up scavenging gas is supplied via a pressure reducing valve (17j and 118)
The gas pipe is dammed on the west side and is led to pipe 141.

In the scavenging gas and the carrier gas generated at the beginning of the desorption phase,
If an excess of gas occurs, these excess amounts of gas are discharged from the line ZO) via the valve (19).

EXAMPLE An adsorbent (reactor) consisting of a cylindrical tube made of silk with an inner diameter of 52 mm and an inner length of 45 mm was filled with activated carbon ss, sy as a stratification agent. The bulk density of this activated carbon was 420 glaze/door, and the specific surface area was about 1150 ηI+/y1111
, Icnmett, and Te.
(according to the measurement S= determined by 1ler). This adsorber has a temperature of 23°C and an absolute temperature of 11-1. In the old crowbar, a certain proportion of air was pumped into the vaporous solvent. The two solvents used in this example are trichlorethylene (0, HOI, )
The inlet concentration of toluene ((!6H50H3) in the supplied air was as follows: nitrichlorotyrene: 0.128 g/1 toluene: 0.086 g/l of air-containing solvent to adsorbent. For adsorption, the concentration of the solvent at the outlet of the adsorber is respectively c!Hc13 0.004 g / 1% 0
6kbQHs was carried out until it rose to 0.002g/1 or more. This is 149.21 of trichlorethylene and 104.81 of l-luene in terms of gas volume. Next, evacuation was performed using a vacuum pump until the pressure PD reached the pressure shown in the table below. At this time, the gas supply valve at the inlet of the adsorber was closed so that the flow direction of gas during desorption was opposite (countercurrent) to the flow direction during adsorption (removal of solvent). When the pressure reaches the value PD shown in the table below, the supply valve (pressure regulating valve) at the adsorber inlet is opened and the scavenger gas (e.g. methane or carbon dioxide, see table below) is flowed into the adsorber. The volume of the scavenging gas for effecting this as well as the layer of solvent desorbed by said scavenging are also given in the table below. Conditions for attaching and detaching C! HOI3 Air 80 28 1υOo, 20H
,502816,911,8 302316,51a,2 Co250 23 17-3 13.930 40 1
2.3 15.2 80 23 15.2 14.9 06H5CH8co250 24 13.2 3.13
0 24 12.4 3.4 Comparative Example An adsorber was filled with activated carbon under the same conditions as in the above example. When 14.5y of 02HOI3 was desorbed using water vapor at a pressure of 1.05 bar and a temperature of 112°C based on the conventional technology, it was found that (about 8.9 y/kg of 1!2HCI31)
00 K, T (kilojoules) were required (no heat loss occurs). The mixture of steam and solvent was subsequently incinerated without heat recovery in the next separation step.

[Brief explanation of the drawing]

The drawing shows, in principle, an apparatus for carrying out the method according to the invention. (2)...Gas supply valve (3)...Adsorbent (
4) Reactor (5) Gas discharge valve (9)
...Vacuum pump (11) ...Gas separation device (condenser) 05 No. ...Pressure regulating valve (17) ...Pressure reducing valve Applicant Belzk 1 Luxpheanosito Gumbh/N- Agent Patent attorney Toyoharu Higuchi and 2 others 7 pages of J-S (no change in content) Procedural amendment (voluntary/method) % formula % Display of the case 1982 Patent Application No. 4058 Name of the invention Carrier adsorbed on an adsorbent Name of the person making the amendment: Belfuge Erg Square/<nt Gmbeno Representative Guilhelm Plant and Ernst Coleman 540 Contents of the amendment ■Representative of the applicant Submit the correction application written in the pitch name, one copy each of the power of attorney and its translation, and the correction drawing attached to the ship's license.

Claims (1)

[Claims] 1. A method of desorbing the organic gas adsorbed from the carrier gas by scavenging the stratifying agent layer in the reactor using a partially adsorbed gas (scavenging gas) , carbon oxide or hydrocarbon having one carbon atom per molecule is used as a scavenging gas at a pressure lower than the pressure at the time of adsorption (desorption pressure).
A method for desorbing an organic gas in a carrier gas adsorbed on an adsorbent, characterized in that it is used in a carrier gas. 2. The method according to claim 1, characterized in that the adsorbed scavenging gas is eliminated by a carrier gas in a new adsorption step; 3. The desorbed organic gas is removed from the reactor. 3. A method as claimed in claim 1, characterized in that the exiting scavenging gas is separated at a pressure higher than the desorption pressure. 4. Method 0 according to claim 2 or δxj4VC, characterized in that the scavenging gas after separating the desorbed organic residue is reused.