JPS5892444A - Adsorptive removal of organic solvent gas - Google Patents

Abstract

PURPOSE:To enhance the removal ratio of an org. solvent gas in an adsorbing and desorbing apparatus, by heating org. solvent gas containing air with high relative humidity to raise the temp. thereof successively in a low temp. range by adding a small volume heating apparatus. CONSTITUTION:Org. solvent gas containing air with high relative humidity exhausted from a painting booth 1 after water washing treatment is heated by a preheater 3 to raise the temp. thereof to 2-15 deg.C or less to lower the relative humidity of air. The gas containing air after the relative humidity thereof is lowered is passed through the adsorbing zone 6a of an adsorbing and desorbing apparatus 5 based on an activated carbon fiber or an activated carbon particulate material to continuously remove the org. solvent gas from air by adsorption.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes activated carbon as an adsorbing material and a nine-smoking desulfurizer to remove the bridged solvent from air containing organic solvent gas discharged from a painting booth, for example. This invention relates to a method for adsorbing and removing gas.

In this type of organic solvent gas adsorption removal method, the following conditions are required to increase the removal rate of bridged solvent gas from the air to be treated.

■ Keep air excess as low as possible.

■ Keep the relative humidity of the air as low as possible.

However, in paint booths, in order to prevent the paint mist contained in the exhaust gas from being released into the atmosphere, a water washing process is generally used in which the exhaust gas is washed with a large amount of water to remove the paint mist. It is being done. Therefore, the relative humidity of the exhaust air from such a booth is approximately 2S.
Therefore, in light of the above-mentioned condition (2), the removal rate of organic solvent gas could not be made sufficiently high.

The following methods can be considered to deal with such a low removal rate, but all of them have drawbacks.

■ The first method is to increase the adsorption capacity of the adsorption material.
For the air to be treated at the same temperature and relative humidity, it is necessary to significantly increase the amount of @adhesion material, or to increase the amount of desorption heated air while keeping the amount of adsorption material the same. According to the above, in both cases, the initial purpose of concentration and removal of the solvent in the desorption air decreases by 14 degrees, and not only does it fail to achieve the initial purpose of concentration and removal, but in the case of a curved person, it is necessary to use Tenryu's adsorbent. The drawback is that the equipment cost increases, and in the latter case, an enormous amount of thermal energy is required to generate desorption heated air, resulting in a shortfall in running costs.

(Rico method: Dehumidify high-humidity air by passing it through a dehumidifier IT K before passing it through an adsorption/desorption device.

When this method is used, the installation of a dehumidifier (condensation type or absorption type) tends to make the entire equipment more complex and larger, and the initial cost is enormous.In addition, the maintenance of the dehumidifier This has the drawback of requiring time and effort for management, reducing the operating efficiency of the equipment and, by extension, reducing the productivity of the coating bag 1d itself.

In other words, in any of the above-mentioned conventional methods, the ability to reliably and sufficiently remove organic solvent gas from high-humidity captive air requires complicated and expensive installations, requires enormous operation and maintenance costs, and is economically unsatisfactory. This method was disadvantageous and could not be called a practical method.

In view of these circumstances, the present invention proposes a method that can reliably and sufficiently remove organic solvents from takaya guest air, while being extremely easy to implement both technically and economically. For the purpose, room temperature air with high relative humidity containing 1r#l solvent gas is heated to an external temperature of about 2 to 7.50 CId, and then passed through the adsorption area of the adsorption device. By this, the organic solvent gas is drawn from the air.
This is a comprehensive summary.

That is, when the air 9 containing bridged solvent gas has a high relative humidity, such as the exhaust gas discharged from a paint booth after being washed with water,
Approximately 2 to 30% of
j'OJ! When heated to a lower temperature, the relative humidity of the air can be lowered, and such an increase in fI
p! ! + The amount of increase in the adsorption removal rate of organic solvent gas obtained from the decrease in relative humidity due to humidity, and the increase in the adsorption removal rate due to heating and temperature increase,
In other words, when comparing the two, the reduction in adsorption removal rate due to an increase in the temperature of the air to be treated (at external heating temperatures in the temperature range mentioned above) is greater in the case of the outer casing, and therefore,
Compared to the case of flowing directly through an empty vC at high relative humidity and room temperature, the rate of adsorption and removal of organic solvent gas can be increased in terms of F-tal. Moreover, in order to improve the low removal rate of organic solvent gas from air with high relative humidity and room temperature, the previously mentioned
Compared to methods (1) and (2), the method of the present invention is structurally simpler and smaller, such as the preheater described later, and
Since all you have to do is add a small-capacity heating device that requires less heat energy, the adsorption/desorption device becomes more complicated and larger, and equipment costs soar. KsJ! is extremely advantageous from an economic point of view, without causing disadvantages such as increased running costs. There are nine things that can be done.

In summary, the present invention provides a means for increasing the temperature of the air to be treated within the above-mentioned temperature range, which has not been adopted in the adsorption/removal method of organic solvent gas using an adsorption/desorption device because the removal rate would decrease. By intentionally adopting this method, we can improve the removal rate of organic gases from high relative humidity room temperature air, which has been a long-awaited goal but could not be achieved, or would incur a huge economic loss if it were to be achieved. It has now become possible to achieve this economically.

In order to clarify the improvement in the removal rate according to the present invention, FIG. 6 is a graph showing the difference in adsorbed air amount QA/adsorbed air amount Qm-M at a specific removal rate between the above temperature range and outside the temperature range. Indicated by

Next, an embodiment of the present invention will be described together with a device used therein.

The first embodiment (see Fig. 1) (1) is a painting booth, and a water washing device (2) is installed at the bottom of the booth (1) to wash the air inside the booth (1) with water and remove paint mist. The air in the painting booth fi+, which passes through this water washing device (2j) and is discharged, has a relative humidity of about 25-25% and a temperature of about 100,000 in the summer!~JJ00
, in the winter//~ko J”O.

(3) is a pre-heater, and the exhaust air is approximately 2 to 1/2
The temperature is raised to below J00, and as this pre-heater, a 2-9 IC heater or a hot water heater, which is generally used for air heating, is used.

fc#'i7 i14# -'? ”,?+F3 in front of Latte
It is provided upstream of the tlNl heapts> to remove minute mistakes F remaining in the discharged air (A).

(5) is an adsorption/desorption device in which activated carbon powder and activated carbon powder are mixed with other fibers and made into paper, and then transferred to a cylindrical hemi-cam-shaped row J (6). Assemble this rotor (6)
A drive device () that rotates in a fixed direction about its center line R17
), the rotor (6) is arranged such that its adsorption area (61) is located in the passage path of the discharged air (A) passing through the front and rear rotors (3), and its adsorption area is (6b) is a device in which the high temperature air for desorption (1!IK) is placed in the path of passage of the hot air, and the adsorption and desorption action is performed continuously as it rotates at that position.This adsorption and desorption device Since the specific structure of (6) is generally well known to those skilled in the art, further detailed explanation will be omitted.

(8) is an air heating treatment device for desorption, and has the following configuration.

The desorption air that has passed through the adsorption/desorption equipment R (5i) passes through the heating side of the first heat exchanger (9) and is heated, and this heated air for desorption is supplied to the catalytic oxidation device (11), In the catalytic oxidizer +1 (l), the solvent gas is catalytically combusted and deodorized.Then, the deodorizing air passes through the deodorizing air vent and the heated side of the first heat exchanger (9) after the deodorizing treatment. (B) is used as a preheating source for heat exchanger (B). The de-aired air (B) that has passed through this 1gl heat exchanger (9) is discharged to the outside air through the heat dissipation side of the first mature exchanger + It). The heating side of this primary heat exchanger (11) is for heating the desorption air X (Bl) facing the adsorption/desorption device (6), and this heated air is purified through a filter (1). It was fresh air.

θ is the second heat exchanger (the path that bypasses the river, and the heat exchanger (11) is added by Ic #P1
The temperature is adjusted to the temperature suitable for desorption by action.

(No. 1 is the preheating burner installed in the above-mentioned oxidizing device. This is a QIFi catalyst. In this way, the air for desorption (gL) is burned and deodorized, and 1. the heat generated by the combustion deodorization is is used to heat the air for desorption.
Incidentally, since the specific structure of the above-mentioned % part is well known, further detailed explanation will be omitted.

The experimental results using the apparatus of this example are shown in FIG.

In the shoe 7 in Fig. 6, the vertical axis is the adsorption area (
The air volume QA passing through the same rotor (6
The ratio of the air volume passing through the persuasion area (6b) of ) per unit time, Rt), and the vortex convergence ratio Mt- are shown. (QJ-M)Q.

The same horizontal axis Fi shows the change in the temperature RTC'C of the air body heated by the preheater (1) and K to be adsorbed.

■ The middle line ■ in the same graph indicates the experimental results under the following condition settings. , Jppvn removal rate v -ys, schi pre-heating relative temperature - 104 desorption adsorption zone supply temperature - / 0°C The organic gas has toluene as its main component.

■ The middle line ■ in the same graph indicates the experimental results under the following condition settings.

QA-/JOOWe/k to song J/”C x = J JP P/V C absolute humidity] removal ll1w*
Solvent gas concentration - / 7 J Organic solvent gas concentration after pprn removal -10, Oppm removal rate is low! 0-1IKI set relative concentration before heating -1σ-.

■ The middle line in the same glass shows the experimental results for the following PP settings.

QAro/ko00nd/ni 16; j Q ℃ Exorcist! 1-1 heating with relative humidity S, S % 1st, 2nd example (see Figure 3) The preheater (ml is an indirect heat exchanger, this heating @
11Ila exchange S tS+ and J heat exchanger (6)
A part of the air for desorption is passed through between the 9 gases for desorption, and the amount of heat generated by the combustion deodorization of 9 gases for desorption is used to raise the temperature of the adsorbed gas.
M is nine things. Other values are the same as in the first embodiment. In addition, it is also good to pass a part of the air that passes through the Jth heat exchanger (llt) and arrives at the heating side of the heat exchanger that is the preheater Ill.

Embodiment J (see Figure 1118) The air heating treatment device for desorption (8) is configured as follows. Others are mentioned above! /! ! The configuration is similar to that of the example.

Out of the filter 0 vague! The heating side of the PcIk1111I indirect heat exchanger 0η (passed through, then passed through the adsorption area of the adsorption/removal end device i!f6+ through the heater 0 barrel, and then the heat absorption side of the indirect heat exchanger 07) 09), and enters the solvent recovery equipment shaft to liquefy and separate and recover the solvent gas, etc.

The structures of each of the above-mentioned parts are well known, and further detailed explanation will be omitted.

Yth embodiment (see Figure 1) In the j*th embodiment 1, the front heater (3
) is used as an indirect heat exchanger, and the treatment device (8
) to partially bypass the desorbed air in Coutts (19) darkness from the heat exchanger 0η. Others are the above j'
j! Same as the example.

Each of the above! i! In the embodiment, it is possible to configure and implement one or more of the following combinations.

(2) The direction in which air passes through the rotor (6) is the radial direction.

■ The adsorption/desorption device +il is not a continuous adsorption/desorption type as described above, but a so-called batch adsorption/desorption device in which adsorbed air and desorbed air are alternately supplied to a chamber made of adsorption/desorption material. It should be of the ceremony.

(2) The front 1 heater (3) is of a burner heating type.

(2) Combustion deodorization in the air heating treatment device for desorption (8) is not limited to melt combustion, but burner combustion should be used.

[Brief explanation of drawings]

The drawings illustrate embodiments of the organic solvent gas adhesion removal method according to the present invention, FIG. 1 is a flowchart showing the v/I/dormitory example, and FIG. 8 is a flowchart showing the co-embodiment.
FIG. 8 is a flowchart showing the first example, FIG. 8 is a flowchart showing the second example, and FIG. 6 is a graph showing the experimental results. (5:... Adsorption/desorption device Figure 2 Figure 3

Claims (1)

[Claims] Air at room temperature with high relative humidity containing organic solvent gas is
~/j" Heating and raising the temperature to below 0, after 9 days, an adsorption/desorption device (6
) A method for removing organic gas by adsorption and removing the organic solvent gas from the air by passing it through an adsorption zone.