SU1744097A1 - Method of solvent recovery - Google Patents

Abstract

SUMMARY OF THE INVENTION: In the method for regenerating a solvent from a solution of an oil or gas by step distillation in the first stage, 2lj - $ Q% of the total solvent is distilled, the solvent distilled off in the first three stages is fed to the heating of the first stage raw material. the steps are divided into two equal flows, one of which is directed to the heating of the second stage feed, 1 or 2 tab.

Description

The invention relates to methods for the regeneration of solvents in oil dewaxing plants and can be used in the refining industry.

Methods are known for the regeneration of a solvent from oil and gacha solutions by evaporation and stripping in distillation columns, as well as drying.

The disadvantage of such methods is their high energy intensity.

The closest to the present invention is the method of solvent regeneration from solutions of dewaxed oil, gaucha or petrolatum, which consists in evaporating it in a system of three to four columns with intermediate heating of the filtrate solution with steam. . .

The disadvantage of this method is the low degree of heat recovery,

solvent, resulting in increased energy costs.

The objective of this is to reduce the energy costs of solvent regeneration.

The goal is achieved by noting that the first stage removes the mass of the solvent from the total amount of solvent and the solvent that is distilled off in the second stage is divided into two equal flows, one of which is directed to the heating of the second stage raw material.

The drawing shows the scheme of regeneration of the solvent.

The scheme contains K-1, K-2, K-3 and K-k - rectification columns, 1-7 heat exchangers, 8-10 refrigerators; I - filtrate stream, C - solvent; III- oil; IV-par.

4 O CO M

317

Filtrate 1 (a mixture of oil and solvent) after heating in heat exchangers 1,2 and 3 enters the K-t distillation column (first regeneration step). Heating of the filtrate in the heat exchanger 1 is carried out with a mixture of the solvent distilled in the K-1 and K-3 columns. The filtrate in the heat exchanger 2 is heated by a half stream of solvent distilled in the K-2 column. The filtrate in the heat exchanger 3 is heated by water vapor. Depending on the composition of the solvent, the temperature of the entrance of the filtrate to K-1 is maintained at a level that ensures the distillation of the mason of the total amount of solvent.

The flow of oil and solvent from the bottom

160 ° C

five

and sent to K-2, where a pressure of 0.32 MPa is maintained. The solvent distillate in K-2 is 66 May D. The remaining solvent is distilled in K-3 and K-, maintaining the temperature at which the raw materials enter the columns at 150-180 ° C. The solvent distilled from K-2; divided into two equal streams, directed the first to heat the filtrate, and the second to feed the K-2.

The consumption of hot steam and water for regeneration and condensation is given in the table. From the data in the table it follows that, compared with the base method, the steam consumption was reduced by 2,000 kg / m and water by 60 m5 / h (by 20 rel).

Example 2. Unlike the example

K-1 columns after heating to heat transfer JJQ pa 1 temperature in K-1 support

in the nickname 4 half of the stream distilled off in the column K-2 and in the heat exchanger 5 enters the column K-2 with sharp water vapor.

The flow of oil and solvent residue from the bottom, K-2 after heating to a heat level of 11 ° C, and a pressure of 0.15 MPa. The distillation of solvent in K-1 is 50 May D. The distillation of solvent in K-2 - 1 May D. Consumption water vapor for

25 heating of the raw material is reduced by 3000 kg / h and the energy consumption for the condensation of solvent vapors by 20 rel. (See table). Example3 In contrast to example 1, the temperature in K-1 is maintained

exchanger 6 with water vapor enters distillation column K-3

Traces of the solvent contained in the oil are stripped in distillation column K-4 at the bottom of which water vapor is supplied as an evaporating agent.

The solvent, distilled off in columns K-1, K-2 and K-3, giving up some of its heat in heat exchangers 1.2 and C, is cooled in refrigerators 8-10. Moreover, the solvent distilled in K-2 is divided into two equal flows, sending the first to the heat exchanger 2 for heating the filtrate, and the second to the heat exchanger for heating the second raw material of the second distillation column K-2.

The invention is illustrated by the following examples.

25 heating of the raw material is reduced by 3000 kg / h, and the energy consumption for condensation of solvent vapors by 20 rel. (See table). PrimerZ In contrast to example 1, the temperature in K-1 is maintained

JQ at the level of 112 ° С, and the pressure of 0.155 MPa. The distillation of the solvent in K-1 is 37.5 wt.%, And in K-2 - 53.5 mas. The consumption of water vapor for heating the raw material is reduced kg / h, and water for condensation of solvent vapors is 35 by 20 rel.% (See table).

Example ((base). The filtrate, consisting of 25 masD of oil, 22.5 masD of acetone and 52.5 masD of benzene and toluene, after heating in raw heat exchangers up to 9 ° C.) Enters column K-1. In the column there is distillation 35 mesD solvent ,, The pressure in K-1 is maintained at 0.16 MPa. The filtrate is heated by mixing the solvent}

Example 1. The filtrate, .., containing 45 K-1, K-2 distilled off in columns, and 20 May oil, U ICE MEK-3, and then direct steam. Flow with

0 masol toluene, after heating down the K-1 is heated with live steam to

raw heat exchangers up to 110 ° C post-1 ° C and sent to K-2, where it is supported falls into the column K-1 (first stage

AND)

regeneration) o. In the column 25 masad of the solvent is distilled off. The pressure in K-1 support 0.16 MPa. The filtrate is heated with a mixture of a solvent distilled in K-and then with a half stream of solvent distilled in K-2 and steam. The stream from the bottom of K-1 is heated by the second half of the stream of solvent distilled in K-2, and then by sharp water vapor to

living pressure of 0.25 MPa. The distillation of the solvent in K-2 is 56 May D. The remaining part of the solvent is removed in K-3 and, while maintaining the entrance temperature to these columns at a level of 1–5 180 ° C. The streams are heated with a sharp steam. At the same time, downstream K- is supplied as a vaporizing agent. The pressure is maintained at 0.16 MPa. Distilled in K-1, K-2 and K-3 solvent after heating

ra 1 temperature in K-1 support

at a level of 11 ° C, and a pressure of 0.15 MPa. Distillation of the solvent in K-1 is 50 May D. Distillation of the solvent in K-2 - 1 May D. Consumption of water vapor for

heating of the raw material is reduced by 3000 kg / h, and the energy consumption for condensation of solvent vapor is 20 rel. (see table). PrimerZ In contrast to example 1, the temperature in K-1 is maintained

at the level of 112 ° С, and the pressure is 0.155 MPa. The solvent distillate in K-1 is 37.5 wt.%, And in K-2 - 53.5 wt. The consumption of water vapor for heating the raw material is reduced kg / h, and water for condensation of solvent vapors by 20 rel% (see table).

Example ((basic). Filtrate consisting of 25 masD of oil, 22.5 mas of acetone and 52.5 mas of benzene and toluo

after heating in raw heat exchangers up to 9 ° C, it enters the K-1 column. In the column, 35 mesD solvent is distilled,. The pressure in K-1 is maintained at 0.16 MPa. The filtrate is heated by blending} a solvent,

driven off in columns K-1, K-2 and K-3, and then direct steam. Flow with

10 ° C and sent to K-2, where

living pressure of 0.25 MPa. The distillation of the solvent in K-2 is 56 May D. The remaining part of the solvent is removed in K-3 and, while maintaining the entrance temperature to these columns at a level of 1–5 180 ° C. The streams are heated with live steam. At the same time, downstream K-i is supplied as a vaporizing agent. The pressure is maintained at 0.16 MPa. Distilled in K-1, K-2 and K-3 solvent after heating

the filtrate is condensed in condensers-refrigerators.

The consumption of hot steam, and the heating is 9200 kg / h. The total1 steam consumption per process is 17,500 kg / h. The consumption of electricity and water is 19,000 kW and 550., respectively. The water consumption for condensation and cooling of the solvent is 300 m3 / h.

Comparison of energy consumption for the implementation of the proposed and known methods is given in the table.

Example 5. In contrast to example 1, the filtrate contains 20% w. „Gacha, instead of oil, the filtrate, after being heated with a half stream of solvent, distilled off in the second regeneration stage (К-6), and then with direct steam to 110 ° C enters the column K -5 (first stage). The remainder of the s-K-5 is first heated with a half stream of solvent, distilled off into K-6, and then with live steam to 1 ° C and fed to K-6. Gatch from bottom K-6 through the hydraulic valve flows into, where the residual solvent is distilled off with water vapor. The solvent’s distillate in K — p is 25 msec, and in K-6 — 66% by weight.

The consumption of live steam for heating is 2100 kg / h, while

F

1.1H

 -hhk ish

t t and t and and

8 3ff,

w uv

The known method is 3070 kg / h, i.e. decreased by 970 kg / cho Water consumption for cooling and condensation of the solvent decreased from 100 m / h to 80 m3 / h

Claims (1)

Invention Formula The method of solvent regeneration from an oil or gacha solution by stepwise distillation of the solvent with the supply of the solvent distilled in the first three steps to the heating of the first stage raw material, characterized in that, in order to reduce energy costs, the mash is distilled off in the first step The solvent and the solvent, distilled in the second stage, are divided into two equal flows, one of which is directed to the heating of the second stage raw material. L 1 I. to-t I well