SU1286252A1 - Method of recuperation of organic solvent from steam and air mixture - Google Patents

Abstract

The invention relates to methods for recovering organic solvents from vapor-air mixtures used in chemical, electrical and woodworking industries and allowing for the reduction of water vapor consumption. The vapor-air mixture containing pyridine is passed through the AP-3 active carbon layer to the flow of impurities, desorption is carried out with a recirculating stream of water vapor until pyridine is released from the layer, the desorbate is cooled to condensation, the aqueous and organic layers are separated. The flow rate of steam is 2-3 kg per 1 kg of pyridine. 1 il. 1 Ta6vT. "(L

Description

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The invention relates to methods for recovering organic solvents from vapor-air mixtures and may find application in the chemical, electrical, woodworking and other industries.

The purpose of the invention is to reduce steam consumption.

The drawing shows a schematic diagram of the installation for implementing the method

The installation contains an adsorber 1 with a loaded layer 2 of activated carbon grade AP-3. The adsorber has the following nozzles: 3 for supplying (supplying) a gas-vapor mixture containing a recuperable solvent; 4 - for removal of non-sorbable components of the mixture; 5 for supplying stripping steam; 6 - for removal of desorption products; 7 - to divert recirculated water vapor flow. Water vapor, for example, saturated (pressure 4-5 bar), is supplied to the adsorber via pipeline 8. The ports 5 and 7 of the adsorber 1 are connected by recirculation pipe 9, containing the steam ejector 10 with a steam inlet pipe 1. Pipe fitting 6, the adsorber 1 is connected via a hydraulic lock 12 to a condenser 13. To switch and control the modes of the solvent recovery process, the installation has control valves 14-19.

The solvent recovery method; the leu is carried out as follows.

The vapor-air mixture to be cleaned through the nozzle 3 with the open position of the valve 15 is sent to adsorber 1, where, when passing through the layer of adsorbent 2, the recovered solvent at 20-40 ° C is adsorbed and remains in the layer, and the non-sorbed components through the nozzle 4 with the open position of the valve 14 output t in the atmosphere. After the adsorbent layer 2 is recuperated with solvent, the valves 14 and 15 are closed and the solvent is desorbed. To do this, the valves 16, 18 are opened, and steam with a temperature of 110-130 ° C is supplied to the adsorber 1 from the pipeline 8, the vapor pressure in the adsorber 1 is set to 0.3-0.4 MPa by the valve 18. The water vapor condensate formed when the adsorber 1 and adsorbent 2 are heated is poured into the trap 12.

When the temperature in the adsorbent layer 2 is equal to (or close to) the temperature of the desorbing steam, the valve 18 is closed, the valve 19 is opened and the desorption steam is supplied to the adsorber 1 through the nozzle 11, the steam ejector 10 and the recirculation pipe 9. The desorption of the adsorbed solvent wire t steam flow recirculating in the circuit adsorber 1 - pipe 7 - steam ejector 10 - pipe recirculation 9 - pipe 5 - adsorber 1. Pressure and speed of the desorbing stream

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ten

15

20

thirty

35

45

in the layer of the adsorbent 2 is set equal to these parameters in the well-known solution by setting the required operating mode of the steam ejector 10 with the valves 17 and 19.

Under the heat and pressure effect of water vapor, the adsorbed solvent desorbs and goes into the recycle stream, constantly increasing its concentration in it. Upon reaching a constant (maximum) level of desorbed solvent in the recirculating desorbing flow (establishing a dynamic equilibrium content of the recovered solvent in the recirculating flow of the desorbing agent and adsorbent) by closing the valves 17 and 19, the recycling is stopped, and the desorbtion products in the vapor state will close the valves 17 and 19 and the recycle will stop the recirculation in the vapor state of the stripping state, and then the closure 17 and 19 will close the recirculation in the vapor state, and then the vaporized air in the vapor state will close the recirculation, and the vapor in the vapor state will close the recirculation, and then the vapor in the vapor state will close the recirculation, and then the vapor in the vapor state will close the recirculation of the vaporized state. 0.3-0.4 MPa, removed from the adsorber 1 through the pipe 6, the hydraulic lock 12 to the condenser 13 by supplying fresh steam from the pipeline 8 through the open valve 18 .

Under laboratory conditions, it was established that the ratio of the heating time of the bed to the time of desorption of the solvent by the recirculating flow m and to the time of withdrawal of the products of desorption is 1: (1.6-2.0): (0.2-0.4).

In the condenser 13, the vaporous desorption products are condensed with the maximum content of the solvent to be recovered in the stripping agent, and the resulting condensate is directed to separation. A gas mixture with a volume flow rate of 2010 containing pyridine with a concentration of 0.01 g / m was used as the starting mixture. The duration of the adsorption stage was limited by the appearance of pyridine behind the layer. Industrial-grade activated carbon of the type AP-3 was used as the adsorbent (the thickness of the annular layer was 0.17 m., Height — 1.5 m, loading weight — 405 kg); Stripping medium — water vapor with a pressure of 0.15 ati and a temperature of 112 ° C.

The table shows the results of a comparative assessment of the desorption parameters of the recovery process in a known manner — flow through desorption and the proposed flow — potoksm circulating in a closed loop.

The heating time of the regenerated a; sorbent, min &

Steam consumption for roar, kg .25

Flow rate; - steam for desorption, kg85 Steam consumption for desorbate output, kg ()

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Table continuation

The specific steam consumption for desorption. To achieve the concentration of pyridine in the desorption products is 0.0004 g / m. kg / min

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kg / kg

A-5

2-3

The content of adsorbed (recovered) components in the desorption products,%

Claims (1)

Invention Formula A method of recovering an organic solvent from a vapor-air mixture, which includes passing it through a layer of active carbon to saturation with a solvent, desorbing the solvent with a stream of water vapor, condensing the desorbent by cooling, and separating the solvent from the condensate, in order to reduce the consumption of water vapor into stages Stripping a stream of water vapor is recirculated until the solvent is removed from the bed. Steam Clean the mixture Cooling water