JPS6197017A - Recovering method of solvent from waste gas - Google Patents

Abstract

PURPOSE:To remove the polymer components contained in a waste gas and to prevent the deterioration of solvent recovery capacity by injecting water to the waste gas between a waste gas generating installation and a solvent recovery installation. CONSTITUTION:After a waste gas which is discharged from a waste gas generating installation 7 and contains solvent plus the resinated polymer is introduced into a cylindrical water spraying apparatus 1 from a gas inlet 2 of the tangential direction and brought into contact with water fed from a water injection port 3, it is sent to a solvent recovery installation18 consisting of an activated carbon adsorption equipment. The liquid separated in the inside of the cylinder is descended to a circulation vessel 5 and separated into tar and water. The gas brought into contact with the injected water is adiabatically cooled and adsorbed on the activated carbon in the low-temp. atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for recovering a bath agent from solvent-containing dead gas generated from a resin manufacturing process or a resin processing process.

[Conventional technology]

Recently, it has been used as a treatment method for waste gas containing bath agents.

Combustion methods and solvent recovery methods are available.

Among these methods, the combustion method involves putting corpse gas into the flame in the combustion furnace and burning it, which is the only way to use fire.

For this reason, they are constantly exposed to dangers such as fire or explosions. In Kozai, safety measures are taken to prevent these dangers, but basically fire is still used (・.For this reason.

Activated carbon adsorbs into the waste gas and eases the solvent.
・Solvent recovery methods are increasingly being used.

In conventional methods for recovering solvents from waste gas, when the only components in the gas are monomers, it is sufficient to directly connect the corpse gas generation unit and the bath agent recovery unit with a duct. On the other hand, if the hot gas contains polymer components other than bath agent components, especially components that turn into fat when cooled, the duct connecting the waste gas generation equipment and the solvent recovery equipment may be heated.

By heating the adsorption section of the solvent recovery equipment.

[The balance that the invention attempts to solve]

In the conventional method, the temperature of the waste gas is lowered to prevent the polymer components in the gas from turning into resin, and the temperature of the adsorption part of the solvent recovery equipment is also raised to lower the temperature of the adsorption reaction with activated carbon, which serves as an absorbent. Raise it (・ta).

These methods lowered the adsorption capacity of activated carbon.

The present invention provides a solvent recovery method that does not reduce bath agent recovery ability even if polymer components are present in waste gas.

The present invention provides a method for recovering solvent by supplying waste gas containing flammable gas from waste gas generation equipment to solvent recovery equipment. The feature is that water is sprayed into the waste gas between the equipment.

The invention will be explained below with reference to the drawings.

FIG. 1 shows a waste gas solvent recovery flow sheet of the present invention.

The waste gas containing the solvent and resinized polymer discharged from the waste gas generating equipment is discharged by the exhaust fan 8 into water! jr casket [1
The gas population is 2. The gas population 2 is preferably located in the tangential direction of the cylinder so that when the waste gas and water come into contact, the water and the tar in the water are separated.

After the inflowing gas comes into contact with water injected from the water injection port 3 at the top of the cylinder, it is discharged as a process gas from the gas outlet 4 and sent to the bath agent recovery equipment by the blower fan 12.

Preferably, the gas outlet 4 is also tangential to the cylinder. The liquid separated in the cylinder falls into the circulation tank 5 at the bottom of the column.

It is separated into tar and water. The separated n7' (water is circulated by the pump 6 as circulating water (injected water).
Separated tar 9 is discharged to the outside of the yarn by a tar discharge pump 10. 11 is a pole tap, and 14 is a new water inlet.

The relationship between circulating water and gas flow rate is circulating water 'I#/gas amount (
The higher the molar ratio), the higher the rate of tar removal from the waste gas.

The gas Vi in contact with the jet water is adiabatically cooled and the solvent (b) is introduced into the adsorption section of the storage facility 18 at 13V. As the bath agent recovery equipment, an activated carbon adsorbent or the like is used. The adsorbent activated carbon in the adsorption section 17 of the solvent recovery facility 18 is sent down to the lower part vc'@ and sent to the desorption section 15, as shown in Figure 1, and circulated through the rL bath agent recovery facility 18. 19 is filled with a regenerated live carbon transport pump. The bath agent is recovered and the fc waste gas is discharged to the outside from the gas generation outlet 21. At this time, the pulp 26 is closed.

During regeneration of the adsorbed activated carbon, the pulp 2.5 is closed and desorbed by nitrogen gas and steam 16. Desorption gas is in cooler 2
2, cooled and condensed with cooling water 22, and recovered as a solution in a recovery tank 23. The activated carbon from which the solvent has been desorbed is again sent to the adsorption section 17 and reused.

[Effect]

Until the FC waste gas flows into the water fog device and reaches a steady state,
Gas components are absorbed into the circulating water and reach saturation. After the circulating water reaches saturation.

Only the tar component in the gas component mixes into the circulating water and is separated in the circulation tank. Therefore, the components in the waste gas that can be absorbed become the outlet gas in the composition state at the time of inflow. However, the gas temperature is adiabatically cooled and falls.

The adiabatically cooled waste gas is led to the gas inlet of the solvent recovery facility and adsorbed on activated carbon in a low temperature atmosphere. Figure 2 shows the difference in adsorption amount of activated carbon depending on temperature. As seen in Figure 2, it can be seen that when the adsorption temperature is low, there are many mature and young trees. Since there is no tar in the inflowing gas and there is no longer a need to heat it for adsorption, the temperature of the adsorption section can be maintained at a low temperature. If the output log gas condensation is 50 ffll/rn' and L7 in the adsorption equimixing shown in Figure 2,
Adsorption*gtsta a℃, sa℃, 3a℃ adsorption-#,
12 each. 23. 2611山-TC/g
-A and C, and the adsorption efficiency is higher at low temperatures (・.

Therefore, at adsorption temperatures of 30° C. and 80° C., the required amount of activated carbon is halved, and the capacity of the device is also halved.

〔Example〕

Dead gas having the "t" component and the tareness shown in Table 1 is discharged from the coating machine at a gas flow rate of 200 Nrn'/min and a temperature of 100°C. The waste gas is introduced into the lower part of the cylindrical water injection device 1 and in the tangential direction of the cylinder by the co-air fan, and is discharged from the top of the water injection device #1 in the tangential direction while spiraling up the inner wall of the cylinder. Ru. The waste gas is in the process of rising in a spiral.

By coming into contact with the water injected from the 7Lfc injection nozzle 3 housed at the top of the water injection device 1, the gaseous tar contained in the j8 gas shell becomes liquid tar? Therefore, circulation tank 5
It settles to the bottom. The water injected from the injection nozzle 6 is separated from the liquid tar 9 in the circulation tank 5 and becomes a supernatant liquid. It is supplied by the circulation pump 6. Gas air volume 20ON
n no Sa, circulating water ii'11.2 ff1'/min
=im water i'1.2rrr'/min = 67k
g-mol/min, gas flow rate 20ONrn'
/min = a 93 kg -mol/min and the liquid/gas ratio is 7.5), the outlet tar concentration is 0.0
51q/mouse, and the tar removal rate is 99.5%.

The injection pressure is 5 kg/-. The waste gas is adiabatically cooled by contact with the jet water, the temperature is lowered to 30° C., and the waste gas is led to the bath agent recovery equipment 18 . The circulating water temperature will be 28°C.

When the generated gas comes into contact with the injected water, steam is included in the gas, so the amount of water in the circulating 1ftR5 decreases. For this reason, a ball tag 11 for own water is attached to the circulation tank 5, and fresh water is supplied from the fresh water inlet port 4. The circulation tank 5 is divided into two tanks to separate the liquid tar 9, and the liquid tar 9 settled in one tank is discharged to the outside of the system by a gear pump 10.
The supernatant liquid overflows into the other tank and is sent to the injection nozzle 6 by the circulation pump.

Table 1 Concentration of log gas entering the water injection equipment Table 2 - Concentration of log gas exiting the water injection equipment Table 1 The log gas entering the water injection equipment shown in Table 1 is 0 after the steady state (saturated state). is removed) and sent as outlet gas to the solvent recovery facility 18 by the blower fan 12.

The inflowing gas is adsorbed by activated carbon in the adsorption section 17, and as shown in Table 2.
It is discharged as outlet gas at a gas concentration of n. The adsorbed activated carbon falls into the desorption section 15 and is regenerated by water vapor and violet, and the desorption gas is condensed by the cooler 22.
It is stored in the recovery tank 23 as a liquid solvent. The amount of solvent recovered was 60 kg/Hr, and the composition of the recovered bath agent was as shown in Table 6.

Table 3 Composition of recovered solvent Regenerated activated carbon is supplied to the top of the adsorption section 17 by a transport pump 19.

〔Effect of the invention〕

1. The polymer component in the waste gas can be removed, and there is no reduction in the recovery ability of the solvent recovery equipment.

2. By cooling the waste gas, the bath agent recovery capacity has been increased and the equipment has become more compact.

[Brief explanation of the drawing]

FIG. 1 shows a flow sheet for solvent recovery of waste gas discharged from waste gas generation equipment. Figure 2 shows the adsorption isotherm solution at each adsorption temperature. Explanation of symbols 1 Water spray device 2 @Gas population 3 Water injection port (
(Speech nozzle) 4 Gas outlet 5 Circulation tank
6 Circulation pump 7 Box gas generation equipment 8 Discharge fan 11 Ball tap 12 Blow fan 13
Adsorption section population 14 Fresh water inlet 15 Desorption section 16 Steam and nitrogen gas supply 17
Adsorption part 18 Solvent recovery equipment 19 Repopulating activated carbon wholesale pump 20 Cooling water 21 Waste gas outlet 22 Cooler 23 Recovery tank 2
4 Delayering gas outlet voltage

Claims (1)

[Claims] 1. In the method of supplying waste gas containing flammable gas from waste gas generation equipment to solvent recovery equipment and recovering the solvent, water is injected into the waste gas between the waste gas generation equipment and the solvent recovery equipment. A method for recovering a solvent from waste gas, which is characterized by: