JPS61129025A - Solvent recovery apparatus - Google Patents

Abstract

PURPOSE:To prevent an initial offset-stream phenomenon, by allowing the opening and closing valve, which is provided to the bypass line for mutually connecting adsorbing tanks, to cooperate with a timer or the thermometer provided to each adsorbing tank. CONSTITUTION:Activated carbon bed adsorbing tanks 3-1, 3-2 are connected by a bypass line 11. When the change-over of each valve performed in the adsorbing tank 3-2 and desorption is performed in the adsorbing tank 3-1, valves 5, 8, 14 are opened and valves 7, 6, 16 are closed and raw gas enters the adsorbing tank 3-1 but, because of the high temp. in the adsorbing tank after desorption, said raw gas is flowed into the adsorbing tank 3-2 through a line 11-1 and the valve 14 in a state containing the solvent not adsorbed by an activated carbon bed 9-1. The temp. of the adsorbing tank 3-2 is low and the entire solvent is adsorbed by an activated carbon bed 9-2 without generating an initial offset-stream phenomenon. The temp. of the adsorbing tank 3-1 is always monitored by a thermometer and, if the temp. in the tank is lowered, the valve 7 is opened while the valves 14, 8 are closed and the adsorbing tank 3-1 is sent to an adsorbing process alone and the adsorbing tank 3-2 is sent to a desorbing process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solvent recovery device. More specifically, the present invention relates to a solvent recovery device that prevents the initial breakthrough phenomenon of an adsorption tank.

[Conventional technology]

Generally, as a method for efficiently recovering solvents and the like from a solvent-containing gas (hereinafter referred to as raw gas), an adsorption method using intermolecular attraction as a collection means is often used, and activated carbon is used as an adsorbent. The activated carbon adsorption method consists of a process in which solvents such as hydrocarbons, alcohols, ketones, and esters are adsorbed onto activated carbon from exhaust gas at approximately room temperature, and a desorption process performed using steam, heated gas, etc.

By the way, as a solvent recovery device, one shown in FIG. 2 is conventionally known. That is, in the figure, 1 is a raw gas, and this raw gas 1 is passed through a filter (not shown) to remove dust, cooled in a cooler (not shown), and then transferred to a proa 2 and an adsorption tank 3-1 ( or 3-2). The adsorption tank 5-1, 5-2 includes valves 5 and 6 that allow the raw gas 1 to flow through the adsorption line 4,
Valve 7 for exhausting the raw gas 1 on which solvent components have been adsorbed.
8 is provided. In addition, in Figure 2? -1.9
-2 shows the activated carbon layer and omits the layering and desorption steps.

For example, the operation using the solvent recovery device described above is performed using the adsorption tank 3.
When -1 is in the desorption process and adsorption tank 3-2 is in the adsorption process, valves 5 and 7 are closed and valve 6.8 is open, and raw gas 1 is passed through valve 6 by proa 2 to adsorption tank 3-2. After the solvent components are adsorbed by the activated carbon layer 9-2, they are released into the atmosphere from the valve 8. In the switching, the valves 5 and 7 are closed, the valves 6.8 are closed, and the raw gas 1 flows into the adsorption tank 3-1.

In this case, due to the characteristics of activated carbon [low-temperature adsorption ← high-temperature desorption], desorption is performed by introducing steam to recover the adsorbed solvent, but for example, the temperature of adsorption tank 3-1 after desorption is approximately 90°C.
(Temperature after adsorption is about 40°C) When switching to the adsorption process, the inside of the tank is not sufficiently cooled, so in the initial state, the solvent is not adsorbed and the raw gas 1 containing the solvent is released into the atmosphere. It had some defects. This phenomenon is called the early breakthrough phenomenon.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a solvent recovery device that prevents the initial breakthrough phenomenon that occurs in the conventional method.

[Means for solving problems]

The present invention includes an adsorption line that leads raw gas to a plurality of adsorption tanks;
In a solvent recovery device comprising a line for adsorbing the solvent in the activated carbon layer of the adsorption tank and releasing it to the atmosphere, and a device for desorbing and recovering the solvent collected in the activated carbon layer, a timer or a thermometer is provided in each adsorption tank. , a solvent recovery apparatus characterized in that a bypass line connecting the adsorption tanks is provided, and an opening/closing valve provided in the bypass line is linked to the timer or thermometer.

[Effect]

The present invention will be explained below based on the drawings.

FIG. 1 is a flowchart outlining the present invention, illustrating the case of a solvent recovery device equipped with two adsorption tanks. Components that are the same as those in the conventional example shown in FIG. 2 are given the same reference numerals, and their explanation will be omitted.

In FIG. 1, 11 is a bypass line connecting adsorption tanks 3-1 and 3-2, 12 is a thermometer provided in adsorption tank 3-1, and 13 is a thermometer provided in adsorption tank 3-2. , 14 is
A first valve provided in the bypass lie/11 and opened/closed via a valve opening/closing device 115 according to instructions from a thermometer 12;
Reference numeral 5 indicates the valve opening/closing device, 16 indicates a second valve of the bypass line 11 which is opened and closed via the valve opening/closing device 17 in conjunction with the thermometer 13, and 17 indicates the valve opening/closing device.

Now, valves 5, 7, 14.16 are closed and valve 6.8 is open, and one raw gas flows into the adsorption tank 3-2 and into the activated carbon layer 9-.
After adsorbing the solvent in step 2, the clean gas is released to the atmosphere from valve 8, and adsorption tank 3-1 is connected to a desorption line (not shown).
It is attached and detached by.

From this state, each valve is switched. Adsorption 4W at this time
The temperature of 5-1 is about 90°C. The status of each valve is
Valve 5, 8.14 is opened, valve 7.6.16 is closed, raw gas 1 enters adsorption tank 3-1, and the solvent that was not adsorbed by activated carbon layer 9-1 due to the high temperature inside the tank is removed. is passed through line 11-1 and valve 14 to adsorption tank 3-
2. The temperature of adsorption tank 3-2 is about 40°C,
All the solvent is adsorbed in the activated carbon layer 9-2 without causing any initial breakthrough phenomenon, and is released to the atmosphere from the valve 8.

The temperature of the adsorption tank 3-1 is constantly monitored by a thermometer 12, and when the temperature inside the tank drops (approximately 60°C), the valve 7 is opened, the valve 14 is closed via the valve opening/closing device 15, and so on. valve 8
is closed, and adsorption tank 3-1 enters the adsorption process independently.
Also, the adsorption tank 3-2 enters a desorption process.

In the case of the next switching, valves 5 and 14.8 are closed and valve 6 is closed.
．． 16.7 is opened, and the same operation as above is repeated.

In the above example, the valve switching timing was illustrated using the thermometer 12.15, but it may also be performed using a timer. In this case, trapping is performed with the expectation that the temperature inside the tank will decrease after a certain period of time.

〔Effect of the invention〕

(1) By providing a bypass line, clean exhaust gas can be released into the atmosphere without causing an initial breakthrough phenomenon.

(2) Since the adsorption tank entering the desorption process receives high-temperature exhaust gas, the desorption preheating time can be shortened and heat can be recovered.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing an outline of an example of the apparatus of the present invention, and FIG. 2 is a flowchart 70- of an example of the conventional apparatus. Multiple agents 1) Meifuku agent Ryo Hagiwara - Figure 1 Figure 2

Claims (1)

[Claims] A solvent recovery system comprising an adsorption line that leads raw gas to a plurality of adsorption tanks, a line that adsorbs the solvent in the activated carbon layer of the adsorption tank and then releases it to the atmosphere, and a device that desorbs and recovers the solvent collected in the activated carbon layer. A solvent recovery device characterized in that a timer or a thermometer is provided in each adsorption tank, a bypass line is provided to connect the adsorption tanks, and an on-off valve provided in the bypass line is linked to the timer or thermometer. Device.