JPS6125601A - Process and device for recovering organic solvent - Google Patents

Abstract

PURPOSE:To improve recovery percentage of an org. solvent from a soln. contg. said org. solvent by condensing the vapor of the org. solvent the recovering the solvent, and feeding back the uncondensed vapor to heating evaporating tank to keep the temp. of the tank at below the b.p. of the soln. CONSTITUTION:A liquid contg. an org. solvent at low concn. is charged and heated in a heating evaporating tank 1. Generated vapor is introduced into a cooling device 2 through a vapor guiding pipe 11 where the org. solvent is condensed. The condensed solvent is separated from the vapor in a tank 3 for the recovered solvent, and the uncondensed vapor is fed back to the tank 1 through a vapor dispersing pipe 7. By this constitution, an improved recover percentage is obtd. without elevating the heating temp. to near the b.p. of the soln.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for recovering organic solvents, in which only organic solvents are collected as a liquid from a solution containing a virtuous solvent.

[Conventional technology and its problems]

Organic solvents from conventional liquids containing organic solvents with low F11 degrees @
There is a distillation method as a method. In the equipment for this distillation method, the above liquid is heated to the boiling point or azeotropic point region of the organic solvent, and this liquid is supplied to the liquid all-St distillation column and heated to nearly 100°C or to the boiling point or azeotropic point of the above organic solvent. Therefore, heaters are expensive, and in wastewater containing metal ions such as calclum and iron, limestone is generated.
The thermal efficiency of the distillation column decreases, and it becomes more troublesome to remove the limestone.

a heating vaporization tank having a heating device, a cooling device that guides the vaporized gas through the heating vaporization tank, cools it, and liquefies it; an FM collection organic solvent tank that supplies gas, stores the gas and liquid, and recovers the liquefied organic solvent; this recovery organic bath agent tank; a heating vaporization tank;
A circuit is connected to the circuit that returns the gasification of unliquefied organic solvent. While recovering the organic solvent, the vaporized organic solvent 05, that is, the unliquefied organic solvent, is returned to the heating vaporization tank again to liquefy the solution containing the organic solvent, and the organic solvent is removed.
It is something that you should do as you are forced to do.

〔Example〕

In order to vaporize the liquid at a temperature below the boiling point using a gas as a circulating medium, it is necessary to constantly renew the gas in contact with the liquid. However, even if a prolific gas is blown onto the liquid surface, the contact time between the gas and the liquid is short and it is impossible to efficiently vaporize the organic solvent.

In order to efficiently vaporize the organic bath agent, K must increase the contact time between the gas and the liquid and the contact surface between the gas and the liquid. Therefore, by diffusing gas into the liquid in the form of fine M9L bubbles, the recovery rate of the organic solvent is improved. An apparatus for recovering this organic solvent is shown in FIG.

In Figure 1, 1 is a sealed S-built heating vaporization tank containing the required amount of food, and sK is equipped with a heater 5, which contains organic solvent at a low concentration or higher concentration. The liquid is heated and the organic solvent in the p liquid is vaporized by the rays until it reaches the saturated vapor pressure at the heating temperature. In addition, a gas supply valve 11 is provided at the top of the heating vaporization tank O, and this pipe 11
0g1A@ is connected to the cooling device 2. As a result, the gas containing the organic solvent vaporized in the tank 1 is supplied to the cooling device 2 through the pipe 11 and is cooled there. By cooling the gas, the gaseous organic solvent condenses and becomes a liquid. A recovery organic solvent tank 3 is disposed at the bottom of this cooling device 2 via a pipe 12t, and the organic solvent that has been condensed and turned into a liquid state in the cooling device is still a gas that has not been condensed in the cooling device. The liquid organic solvent is led out to the tank 3 together with the liquid organic solvent, and in this tank 5, the liquid and gas are separated and only the liquid organic solvent is recovered. The gaseous organic solvent is transferred to this tank 3 and heating vaporization tank 1 a! Continued return? 1
After 1t4, it is returned to the heating vaporization tank. At this time, it is desirable that the liquid be returned to the liquid in the heating vaporization tank, so in FIG.
The tip of the snow is provided with an aeration pipe 7f installed at the bottom of the heating vaporization tank or in the liquid, so that the return gas is forcibly diffused into the liquid in the tank.

In Fig. 2, the gas in the return pipe is forced into the liquid in the tank by rotating the stirring blade in the liquid and using the negative pressure generated in the liquid, without using a blower or diffuser. This is an embodiment in which the device 8 is used to form bubbles and release them.

In addition, in the embodiments shown in Figures 1 and 2, if the concentration of the recovered liquid organic solvent is low and it is necessary to further increase the concentration, the above-mentioned device, that is, heating vaporization tanks, may be installed in series. , this embodiment is shown in FIG. 9 in Figure 6
13 is a processing tank, 13 is a pipe line, 14 is a liquid supply pipe, and 15 is an outflow pipe.

The following table shows the temperature, saturated vapor partial pressure, and methanol concentration of the methanol water bath.

As can be seen from this table, the lower the temperature, the lower the saturated vapor partial pressure. However, if the methanol content in the steam is high, the methanol concentration that can be recovered in the cooling section increases.

The following table shows the temperature, saturated vapor partial pressure, and methyl ethyl ketone concentration of the methyl ethyl ketone concentration liquid.

〔Effect of the invention〕

When recovering 1 gI of methanol using the conventional distillation method, in order to increase the recovery rate, the temperature of the solution had to be raised to 100°C as the methanol concentration in the solution decreased, as shown in Figure 4. In the case of a misfire, the vaporized methanol is guided to a cooling section using a gas such as air as a medium, and is condensed and liquefied to be recovered, so even if the temperature of the solution is constant, a recovery rate of 95≦ or more can be obtained. It has the advantage of being able to

[Brief explanation of drawings]

1 and 2 are examples, FIG. 5 is a different example, and FIG. 4 is a graph. 1 is a heating vaporization tank, 2 is a cooling device, 6 is an organic solvent tank, 4 is a skin return tube, 5 is a heater, 6 is a pump, 7
is an aeration pipe, and 8 is an aeration device. Figure 1 Figure 2

Claims (2)

[Claims] (1) A solution containing an organic solvent is heated in a heating vaporization tank, the vaporized organic solvent is cooled and the liquefied organic solvent is recovered, and the unliquefied organic solvent of this vaporized organic solvent is reheated and vaporized in the vaporization tank. A method for recovering an organic solvent, which comprises recovering the organic solvent by liquefying it from a solution containing the organic solvent so as to return it to the organic solvent. (2) A heating vaporization tank that supplies a solution containing an organic solvent and has a heater, a cooling device that guides the vaporized gas from the heating vaporization tank, cools it, and liquefies it; A recovery organic solvent tank is connected to a recovery organic solvent tank that supplies an unliquefied gas together with an organic solvent, separates the gas and liquid, and recovers the liquefied organic solvent. An organic solvent recovery device consisting of a circuit that returns the gasified gas.