SU789570A1 - Method of regenerating solvents from inert gas in deparaffinizing and oil removing processes of oil raw material - Google Patents

Description

378 we are in water (for example, acetone, methyl ethyl ketone). Solvent components that do not have sufficient solubility in water (benzene, toluene, etc.) cannot be extracted from the inert gas by this method. As a result of direct contact of the inert gas with water during the absorption process, the inert gas is saturated with water vapor, and when it is cooled to (-40) ° C and below, ice will accumulate on the heat transfer surface of the refrigeration equipment, which leads to a complete cessation of heat exchange in these devices. To cool the inert gas to very low temperatures of - (-40) ° C and below, more heat transfer surfaces will be required due to the low heat transfer coefficient when the inert gas is cooled to about 20 kcal / mh - ° C. At the same time, this method does not exclude the loss of solvents with an inert gas, since even at very low temperatures (minus 40 ° C and below) the elasticity of solvent vapors is not zero. The object of the present invention is to more completely remove solvent vapors from inert gas and simplify the process. The goal is achieved by the fact that in the method of regenerating solvents from an inert gas in the processes of dewaxing and deoiling of petroleum feedstock by absorption of solvent vapors by the absorbent, the raw materials or products obtained in the processes of dewaxing or deoiling are used as absorbent at 20- 80 ° С with the subsequent supply of the partially inert solvent-free inert gas to the adsorption by the solid adsorbent followed by the desorption of the solvents with steam, cooling, and separation of solvents from water. The adsorption is carried out at 25–40 ° C. The drawing is a schematic process diagram of a method for regenerating solvents from an inert gas. The scheme includes a pump 1, an absorber 2, an adsorber 3-Over, a condenser-cooler 4, a decanter 5, as well as flows: 1 — an inert gas containing solvent vapors from compressors of the dewaxing or de-oiling plants; 11-absorbent, ltl-inert gas, partially freed from solvent vapors, IV - sorbent, saturated with solvents; V-inert gas, completely freed from solvent vapors; VI — water vapor; VII — mixture of water vapor with solvent vapors; VIII solvents extracted from inert gas into the system of the installation for use in the process: IX - water mixed with solvents on the ketone column of the installation. Inert gas, discharged from the dewaxing or de-oiling installation system, enters through line I into the lower part of the absorber 2 of the disk or nozzle type, in the upper part of which, using a pump 1, they or with several flows in height along the line II feed the plant's absorbent feed or its products. recycling. From the lower absorber 2, the solvent-rich raw material (absorbent) is sent to the paraffin crystallization unit, and if processing products are used as the absorbent, they are returned to the unit after saturation with the vapor of solvents in order to distill the absorbed solvent on the equipment of the corresponding section of the regenerating unit . From the top of the absorber, an inert gas, partially freed from solvent vapors, is fed via line III to adsorber 3 with a fixed bed of adsorbent. The inert gas, completely freed from solvent vapors, is discharged via line V to the atmosphere. When the adsorbent is saturated with the solvents in the adsorber 3, the inert gas supply is switched to the similarly designed adsorber Za, and in the adsorber 3 the solvent is desorbed and the adsorbent is regenerated. Desorption is carried out with live steam through line IV for 10-30 minutes. A mixture of solvent vapors and water, obtained as a result of desorption, is fed via line VII to air or water-cooled condenser. Dilc 4; the condensate, the stack in the decanter 5, is divided into two layers: a solvent layer (upper) and an aqueous layer with a mixture of solvent (lower). Both products are returned to the unit via lines VIII, IX, and layers of solvents are fed to the wet solvent system for direct use in the process, and the aqueous layer is sent to the ketone column (contained in each dewaxing and deoiling unit) to separate traces of the solvent from water . The expediency of choosing the process raw material as an absorbent is explained by the considerable simplification of the technological scheme of the system for trapping solvents, since in this case the regeneration of solvents from the absorbent is not required; the raw material saturated with solvents can be sent directly to the unit. paraffin crystallization. In the case of using low-melting products of the dewaxing and de-mashing processes as an absorbent, the regeneration of solvents from the approached absorbent is carried out on the equipment contained in each installation simultaneously with the regeneration of solvents from solutions of the dewaxed oil or de-oiling filtrate. It is also possible to use high-melting tr as an absorbent: refined products (paraffin, ceresin, gach, petrolatum), and this necessitates an increase in the temperature regime of the absorption process and forced heating of all apparatus, valves and pipelines in connection with the increased melting temperature of these products. The absorption process is carried out at 20-80 ° C and the multiplicity of treatment of the inert gas with an absorbent from 5 to 120 kg / m, the most preferable temperature mode of absorption of HF-C and the frequency of processing of the inert gas with an absorbent is 20-50 k1 / m, with the degree of extraction the solvent on the absorber unit can reach 80-95%. The use of higher temperatures reduces. absorption efficiency, and higher ratios of treatment of the inert gas with the absorbent, do not significantly increase the degree of solvent recovery, but require an increase in the diameter of the absorber. As an adsorbent in adsorbers 3, For the use of granular or briquetted activated carbon is assumed. It was established that the adsorption cycle should be carried out with a gas inert gas flow rate of 200–2000 m per hour per 1 m of the adsorbent and a temperature of 23–40 ° C. The recommended degree of adsorbent adsorbent is 12–15 wt. % The desorption cycle is carried out by feeding steam into the upper part of the adsorber for 10-30 minutes in an amount of 3-5 parts by weight. on the adsorbed solvent. At the end of the desorption cycle with inert,. leaving the working adsorber, the adsorbent is cooled for 20–30 mu, after which the adsorber is again ready to work. Example 1. The inert gas is impregnated with acetone-toluene solvent vapors, taken in a ratio of 40-60% by volume, at 20-25 ° C and under-. into the lower part of the glass absorber filled with a layer of glass nozzle. Absorbent raffinate of 320-440 ° C fraction of Western Ukrainian oil is fed to the upper part of the absorber, which is used as a raw material in an industrial dewaxing plant. Rafi properties; Nata: density at 70 ° С 0.828, melting point 35.1 ° С, viscosity at 70 ° С 6.79 cSt. Technological conditions and the results of the experiments are given in table. one.

10.9

10.7

10.3

10.7

10.0

10.2

9.3

73.2 80.6

8.9

10.6

96.4 105.7

10.6

9.3 105.1

9.5 112.0

As can be seen from the table. Ij optimal area. Inert gas partially freed from

 absorption for a given absorbent in-. solvent vapors, then sent to laboratories at the temperature of 3B-C 0 and frequency multiplier adsorber filled with fixed

inert gas treatment with an absorbent of 30-70 kg / m, 25 layers of granular activated carbon, in which the degree of extraction of the solvent Adsorption is carried out at 25-40 ° C. The result is 85-91%.

As can be seen from the table. 2, the optimum saturation level of the adsorbent, at which complete extraction of solvent vapors from 1-unit gas is achieved, is about 15%.

In the experiment, where the degree of saturation of the adsorbent with solvents was 15.3 wt.%, The solvent components were desorbed from activated carbon vapor at 130 ° C. Steam is supplied for 25 minutes at a flow rate of 4.2 kg per I kg of desorbed products. At the same time almost half of the continuation of the table. one

90.4 86.7 90.6 87.0 87.1 79.0

table 2

to desorb the activated carbon solvent components.

After cooling and separation from water, solvents can be used in the dewaxing and de-oiling processes.

A pp and -m e p 2. The inert gas is saturated with methyl ethyl ketone-toluene solvent vapors, taken in a ratio of 60:40 vol.%, At 20-25 ° C and fed to an absorber, in which

978957010

the absorbent use de-oiling filtrate, pour point (-7) ° C, viscosity when obtained at oil-free distillate, 70 ° C 6.4 cSt, refractive index at 70 ° C

fractions 320-420 С of mangyshlak oil. 1,4658. Technological conditions and results

The properties of the filtrate: fatigue at 70 ° С 0.841. the experiment is given in table. 3. From table. 3 it follows that in the case under consideration, the optimal absorption rates are achieved in the temperature range of 30-60 ° C and, under multiples of treatment of inert gas of 30-80 kg / N, under these conditions, the degree of solvent recovery reaches 89-95%.

Table 3.3 The inert gas, partially freed from solvent vapors, is sent to an adsorber filled with a fixed bed of activated carbon. Adsorption is carried out at 25-40 ° C. The results of the experiments are shown in Table 4. Table 4

As can be seen from the table. 4, when the adsorbent is saturated to 15%, complete removal of solvents from the inert gas leaving the adsorber is ensured.

In the experiment, where the degree of saturation of the adsorbent with solvents was 15.0 wt.%, The solvent components were desorbed from water-activated vapor at 130 ° C. The steam was fed for 20 minutes at a flow rate of 4.8 kg per kilogram of desorbed products. Comrade An almost complete desorption of the activated carbon solvent components has been achieved. .

The proposed method for the absorption of solvent vapors by a hydrocarbon absorbent instead of water makes it possible to extract deeply from an inert pelvis. Not only the lower ketones, but also other components of the solvent that are not recoverable by water (benzene, toluene, etc.).

Due to the use of an adsorption method for extracting solvents from an inert gas at the final stage of the process, the method does not require cooling the inert gas to low temperatures, which eliminates the need for expensive installation of refrigeration equipment and the costs associated with deep cooling of the inert gas.

The method makes it possible to completely prevent the loss of solvents with an inert gas, which cannot be achieved using a known method.

Claims (3)

1. A method for regenerating solvents from an inert gas in dewaxing and de-oiling processes of oil by absorbing solvent vapors with an absorbent, characterized in that, in order to more completely remove solvents from an inert gas and simplify the process, raw materials or products are used as an absorbent B dewaxing or deoiling, and absorption is carried out at 20-80 ° C, followed by supplying the partially inert solvent vapors of the inert gas for adsorption by a solid adsorbent, followed by desorption of the solvents with water vapor, cooling and separation of the solvents from water. 2. A method according to claim 1, characterized in that the adsorption is carried out at 25-40 ° C. Sources of information taken into account during examination 1. Chesnokov, AL and others. Deep oil dewaxing. Chemistry, 1966, p. 25-27. 2. In the same place 58. 3. USSR author's certificate number 487105, cl. C 10 G 43/04, 1975 (prototype).