JPH04131120A - Solvent recovery apparatus - Google Patents

Abstract

PURPOSE:To restore the function of an activated carbon adsorbing part by constituting the activated carbon adsorbing part of two or more activated carbon beds parallelly arranged in the advance direction of solvent gas and replacing only the activated carbon bed positioned on the suction side of the solvent gas as the outermost bed among the activated carbon beds at the lowering time of capacity. CONSTITUTION:In activated carbon adsorbing part A for adsorbing solvent gas, a desorbing vapor supply part 14 for desorbing the solvent gas adsorbed on the activated carbon adsorbing part A, a condensing part 15 for condensing the desorbed solvent gas and a separation part 16 for separating the condensate in the condensing part 15 are provided. The activated carbon adsorbing part A is constituted of two or more activated carbon beds (e.g. an activated carbon bed 2 for removing high b.p. impurity and a usual activated carbon bed 3) parallelly arranged in the advance direction of the solvent gas. That is, when required adsorbing capacity is not developed because of the lowering of adsorbing capacity due to high b.p. impurity with the elapse of time, only the activated carbon bed positioned in the outermost bed on the suction side of the solvent gas within the activated carbon bed is replaced to restore adsorbing function and running cost is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a solvent recovery device used for recovering a solvent from a mixed gas of a solvent and air.

(Prior Art) Traditionally, volatile organic solvents are mainly used in industries such as paints, printing, adhesive tapes, and dry cleaning, but these organic solvents are expensive, have the risk of explosion, and are harmful to human health. Since the solvent gas is also harmful to the atmosphere, the solvent gas contained in the exhaust gas from manufacturing equipment or processing equipment is captured or collected, and the purified air is released into the atmosphere. The solvent recovery device used for this purpose usually has an activated carbon adsorption section as shown in FIG. 4, and the activated carbon adsorption section is provided with an activated carbon layer a for taking in the solvent gas and adsorbing it. The solvent gas sent from the solvent gas inlet passes through the passage C, flows in the direction of arrow d, and when passing through the activated carbon layer a, it adsorbs the solvent gas, and finally passes through the gas outlet. It flows out from e. In addition, when the activated carbon layer a becomes saturated with the solvent gas over time and its adsorption capacity decreases, high-pressure steam is blown onto the activated carbon layer a in the opposite direction to the solvent gas (in the direction of arrow f). The adsorption capacity is restored by evaporating the solvent (this operation is called "desorption"), and for this purpose, as shown in the layout of the apparatus of the present invention shown in Fig. 3, a vapor supply for desorption is performed. Part 14
Furthermore, a condensing section 15 for condensing and liquefying the solvent gas evaporated by desorption using a water-cooled condenser or the like;
It has a separation section 16 for separating the condensed liquid in the condensation section 15 into water and a solvent.

Therefore, in Fig. 4, the activated carbon adsorption part a is supported by overlapping wire mesh retainers i made of steel materials such as angles in a lattice shape on the inflow side g and outflow side of the solvent gas. Wire meshes (indicated by broken lines) are arranged and fixed to the trunk wall, top plate, and floorboard of the solvent recovery device, and activated carbon (not shown) is introduced into the mesh through the entrance/exit at the top. .

(Problem to be solved by the invention) However, since the solvent to be recovered contains many impurities with high boiling points, the adsorption capacity decreases due to the adhesion of these impurities to the activated carbon layer, resulting in adsorption and desorption. This will force the cycle to be shortened.

As a result, in the conventional solvent recovery equipment described above, the amount of steam used for desorption increases, and to avoid this, it is necessary to frequently replace or regenerate activated carbon. The drawback was that running costs were high.

Therefore, in view of the drawbacks of the prior art such as sloping up, the inventors of the present invention aimed to provide a solvent recovery device that is excellent in maintaining recovery efficiency and has low running costs. It was found that the decrease does not occur in the entire activated carbon layer, but is limited to a relatively shallow layer from the surface j on the solvent gas inlet side in Figure 3.
This led to the completion of the present invention.

(Means for Solving the Problems) The present invention provides an activated carbon adsorption unit for adsorbing a solvent gas, a desorption steam supply unit for desorbing the solvent gas adsorbed by the activated carbon adsorption unit, and a desorption vapor supply unit for desorbing the solvent gas adsorbed by the activated carbon adsorption unit. In a solvent recovery device having a condensing section for condensing the liquid and a separating section for separating the condensed liquid in the condensing section, the activated carbon adsorption section has two or more layers arranged in parallel in the direction of movement of the solvent gas. The gist of the bag is a solvent collection bag characterized by being made of an activated carbon layer.

(Function) In the present invention, since the activated carbon adsorption section is composed of two or more activated carbon layers arranged in parallel in the direction of movement of the solvent gas, the adsorption capacity decreases over time due to high boiling point impurities. When the adsorption capacity is no longer exhibited, the function can be restored by replacing only the activated carbon layer located at the outermost layer on the solvent gas suction side among the activated carbon layers.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

Fig. 1 is a schematic front sectional view of the activated carbon adsorption section A of the device of the present invention, and Fig. 2 is a partially cutaway plan view of the same. It has a cylindrical shape. 2 is an activated carbon layer for removing high boiling point impurities, 3
is a normal activated carbon layer superimposed on the activated carbon layer 2 for removing high-boiling point impurities, and a partition wall 6 is composed of a wire mesh retainer 4 and a wire mesh 5 (shown by broken lines) superimposed on and supported by the wire mesh holder 4. The activated carbon layer 2 for removing high-boiling point impurities is slightly thinner. The edge is attached to the top plate 8.

An inclined plate 10 is provided on the floor plate 9 to facilitate the flow of solvent gas upward, and a passage 11 for the solvent gas is formed between the inclined plate 10 and the activated carbon layer floor plate 7. .

The operation of the device of the present invention will be explained based on the above embodiments.
The solvent gas is sent through the solvent gas inlet 12, passes through the passage 11, and then flows in the direction of the arrow. At this time, it first passes through the activated carbon layer 2 for removing high-boiling point impurities.
At that time, high boiling point impurities are blocked by the activated carbon layer 2 for removing high boiling point impurities, and then the solvent gas is adsorbed by the activated carbon layer 2 for removing high boiling point impurities and the normal activated carbon layer 3, and finally the gas outlet It flows out from 13.

In addition, in the case of desorption, in the layout of the entire apparatus of the present invention shown in FIG. (in the direction of arrow F), absorbs the solvent during this period, flows out from the solvent gas inlet 12, is then sent to the condensing section 15 where the desorbed solvent gas is condensed, and is further fed into the condensing section 15 where the desorbed solvent gas is condensed. Separation section 16 for separating the condensed liquid
sent to.

Over time, if the desired adsorption capacity is no longer exhibited due to a decrease in adsorption capacity due to high-boiling impurities, only the activated carbon layer 2 for removing high-boiling impurities among the activated carbon layers needs to be replaced. When replacing the activated carbon, it is sufficient to suck it out from the activated carbon inlet/outlet 17 at the top and insert new activated carbon.

In the above embodiment of the present invention, the activated carbon layer is an example in which an activated carbon layer for removing high-boiling point impurities and a normal activated carbon layer are arranged side by side, but the invention is not necessarily limited to this example, and each The number of activated carbon layers may be arranged in parallel, and is appropriately determined depending on the overall size of the recovery device, the amount to be recovered, the type of solvent, the air blowing function, and other factors.

In the above embodiments of the device of the present invention, the overall shape of the device is shown to be cylindrical, but the device is not necessarily limited to this. The shape may be appropriately set such as an elliptical shape, a pyramidal shape, a conical shape, etc. based on the type of solvent, the concentration to be recovered, the installation space, and other factors.

In the above embodiment of the device of the present invention, the partition between the activated carbon layer for removing high-boiling point impurities and the normal activated carbon layer, as well as the inflow and outflow sides of the solvent gas, are supported by a wire mesh holder and stacked thereon. A fixed partition wall consisting of a wire mesh was used, but if the device is relatively small, for example, the activated carbon layer for removing high boiling point impurities and the normal activated carbon layer can be taken out separately. Furthermore, in the above embodiment of the device of the present invention, the activated carbon layer for removing high-boiling point impurities in the activated carbon layer and the normal activated carbon layer are overlapped, but there is no space between the two layers. may be provided.

(Effects) In the solvent recovery device of the present invention, since the activated carbon adsorption section is composed of two or more activated carbon layers arranged in parallel in the direction of movement of the solvent gas,
Over time, the adsorption capacity decreases due to high boiling point impurities.
When the desired adsorption capacity is no longer exhibited, the function can be restored by replacing only the activated carbon layer located at the outermost layer on the solvent gas suction side among the activated carbon layers.

Therefore, the cost of replacing the activated carbon layer is about half or less of the conventional cost, making it possible to gradually reduce running costs and providing an apparatus that is excellent in maintaining recovery efficiency over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a schematic front sectional view of the activated carbon adsorption unit A used in the device of the present invention, FIG. 2 is a partially cutaway plan view of the same, and FIG.
FIG. 4, an explanatory diagram showing the overall arrangement of the solvent recovery device of the present invention, is a schematic front sectional view showing an activated carbon adsorption section used in a conventional solvent recovery device. A... Activated carbon adsorption part, 1... Trunk peripheral wall of activated carbon adsorption part, 2
・・Activated carbon layer for removing high boiling point impurities, 3.・Normal activated carbon layer, 4.・Wire mesh holder, 5.・Wire mesh, 6.・Partition wall, 7.・Activated carbon layer floor plate, 8.・Top plate, 9・・Floor board, 10
... Inclined plate, 11. Solvent gas passage, 12. Solvent gas inlet, 13. Gas outlet, - The above-mentioned supply section for desorption, - Condensation section, - Separation section.

Claims (1)

[Claims] 1. An activated carbon adsorption section that adsorbs solvent gas, a desorption steam supply section that desorbs the solvent gas adsorbed on the activated carbon adsorption section, a condensation section that condenses the desorbed solvent gas, and a condensation section that condenses the desorbed solvent gas. A solvent recovery device having a separation section for separating condensate, wherein the activated carbon adsorption section comprises two or more activated carbon layers arranged in parallel in the direction of movement of solvent gas. Device.