SU1595877A1 - Method of preparing pyro-gas to separation - Google Patents

Abstract

This invention relates to petrochemistry, in particular to the preparation of pyrogas for separation. The goal is to increase the release of heavy C 4 hydrocarbons and reduce energy costs. After the first stages of compression and cooling, the pyrogas is subjected to absorption in a fractionation absorber (ethylbenzene in a mass ratio of 3-5: 1 pyrogas, respectively). The process is followed by the stripping of light hydrocarbons from the fat absorbent in a stripping column, into which simultaneously with the fat absorbent condensate is fed, separated in the first compression stages, and desorption of heavy hydrocarbons from the stripped fat absorbent in the stripper. The pyrogas leaving the fractionation absorber and the stripped light hydrocarbons are combined and fed to subsequent compression and cooling stages with the supply of the condensate separated in this way to the fractionation absorber. 1 il. 4 tab.

Description

Noah 7, where it is cooled to 40 ° C. Next, in the propylene refrigerator 8, the cake 3 is cooled to and partially condensed. The vapor-liquid mixture after cooler 8 is sent to separator 9 to separate condensate from gas. The condensate from the separator 9 is discharged into the collection Zo. Gas from the separator 9 is fed to the suction of the second stage 10 of the pyrogasic compressor. After compression in the second stage, the pyrogas with a pressure of 6.5 at and 73 ° C are cooled in a water cooler 11 to, and in a propylene cooler 12 - to 6 ° C and partially condensed. The condensate is separated from gas B to the separator 13, from where the condensate is pumped to pump 14 by the pump 14.

The pyrogas after the separator 13 is fed to the food fractionation absorber 15o. The operating mode of the fractionation absorber: pressure 6.5 atm; top temperature 23 ° C; the temperature of the bottom of the column Pyrogaz from the top of the absorber 15 enters the third stage 16 of the pyrogas compressor. After the third stage of compression 16 with a pressure of 20 at and a temperature of 77 ° C, pyrogas is cooled in a water cooler 17 to 40 ° C, in a propylene cooler 18 - to 20 ° C and partially condensed. The condensate is separated from the gas in separator 19. From the separator. the condensate is throttled (20) to 6.5 ata and attached to the pyrogas coming from the separator 13 to the absorber 15. On the top of the absorber 15 serves a lean absorbent (ethylbenzene B ratio to pyrogas 3: 1 - 5: 1) from desorber 21. The bottom product of column 15, containing ethylbenzene, C4 hydrocarbons and above, is cooled in a refrigerator 22 up to 20 ° C and fed to a stripping column 5. The stripped hydrocarbons from the top of column 5 are attached to a pyrogas fed to a third compression stage 16 of a pie-gas compressor.

The operation mode of the Stripping column 5: pressure 3., 5 at; top temperature 15 ° С; Cube temperature 75 C.

The fat absorbent from the bottom of the stripping column 5 is fed to the power supply of desorber 21. The operating mode of desorber 21: pressure 1.5 atm; cube temperature

The lean absorbent is cooled in a true refrigerator 23 before and fed into the buffer tank 24, which serves to accumulate the absorbent, supply fresh and remove the spent absorbent. After the container 24, the absorbent is directed to the upper plate of the absorber 15 by the pump 25. The gas from the separator 19 is directed to the inlet of the fourth stage 26 of the pyrogas compressor. After compression in compressor 27, pyrogas with a temperature and pressure of 42 atats are cooled to 5 and through a desiccant 28 with a hydrocarbon content of C and above less than 6.07 mol.% Are sent for further processing — gas separation.

Q Example 1. Pyrogaz is prepared according to the described scheme. The composition and amount of the initial pyrogas are given in table. 1 - 4. It also shows the composition and quantity of material. 5 streams, indicated in the drawing by the numbers I - XIV. The composition of pyrogas is determined by chromatography. Ethylbenzene is fed to the absorber 15 with a 4: 1 mass ratio of ethylbenzene and pyrogas. The amount of C-C hydrocarbons in the starting pyrogas is 31.6% by weight, the amount of absorbed is 29.752 mol%.

The recovery efficiency of heavy hydrocarbons C, according to the proposed 35 method, is estimated by the degree of extraction of alkadienes, which is the ratio of the sum of absorbed hydrocarbons C from the pyrogas composition of stream IV to their sum in use.

40

driving flow IV.

29 752

The degree of extraction -rf-7 is 0.94.

L, D

Example 2 was carried out under conditions similar to those described in example 1, but with pyrogas consumption entering the absorber 15, 10 kg / h, and ethylbenzene - 30 kg / h, which corresponds to a mass ratio of ethylbenzene and pyrogas 3: 1.

In tab. Figure 5 shows the composition of the gas entering the absorber (stream IV) and exiting the absorber (stream VII).

The sum of the C-Cj hydrocarbons in the starting pyrogas is 28.608 mol%. The amount of absorbed hydrocarbons from the pyrogas composition is 24.508 mol%. Power

and: attraction equals 24,508

 - P Q

28,608

The composition of pyrogas (stream XIV) on during the installation is given in table 6.

Example 3. Pyrogas separation is carried out under conditions similar to those described in Example 1, but the amount of pyrogas entering the absorber is 12 kg / h, and the amount of ethyl benzene is 24 kg / h, i.e. mass ratio of ethylbenzene and pyrogas 2: 1 o The content of hydrocarbons S.-S. in stream IV, it is 26.139 mol%, and the amount of absorbed hydrocarbons C, -Cj is 21.039 mol%. Power

21 039 extracts ° The composition of the pyrogas coming out of the installation is given in tablo 6o

Table 5 shows the composition of flows IV and VII „

Example 4 The test was carried out under the conditions described in example 1, but with a pyrogas consumption (flow IV) 5 kg / h and ethyl benzene 25 kg / h, which corresponds to a mass ratio of ethyl benzene and pyrogas 5: 1.

Table 5 shows the composition of flows IV and VII. .

The amount of hydrocarbons in the starting pyrogas is 1.9608 mol% the amount of hydrocarbons absorbed is 15.89 mol% 0

The degree of extraction is 1-AO2

15.9608 0.995.

The composition of the pyrogas output from the installation is shown in Table 6.

Example 5 For comparison, chromatographic compositions of pyrogas were obtained before and after the distillation method for recovering heavy hydrocarbons of C 4 and higher at the stage of preparing pyrogas for gas separation by a known method. The sum of hydrocarbons in pyrogas entering rectification is 13.2063 mol%, the sum extracted coal 958776

levodorod from the composition of pyrogas - 4.5980 mol L o

The recovery rate is 5 52 "5

13.2063

Pyrogas compositions before and after separation of heavy hydrocarbons are higher and the calculation results are given in Table 10. 5o

In tab. 6 shows the composition of pyrogas, prepared by a known method.

In tab. 7 shows data on 15 energy consumption per 1 ton of olefins in the preparation of pyrogas in examples 1-5.

20

Claims (1)

Invention Formula A method of preparing pyrogas for separation by multistep compression with cooling and separation of condensate formed during this process, 25 includes the separation of heavy hydrocarbons C., which is different in order to increase the degree of separation of heavy hydrocarbons C and reduce energy consumption, after the first stages of compression and cooling, pyrogas 30 is subjected to absorption in a fractionation absorber using ethylbenzene as an absorbent, taken in a mass ratio J to pyrogas 3-5: 1 corresponding to absorption This is followed by the stripping of light hydrocarbons from the black absorbent in the stripping kolk-3, into which the condensate separated in the first compression stages and the desorption of heavy hydrocarbons from the stripped fat absorbent in the stripper are fed simultaneously with the fat absorbent The pyrogas from the 5 fractional absorber and the stripped light hydrocarbons are combined and fed to the next stages of compression and cooling from the inlet. whose separated condensate is 0 into a fractionation absorber. t h R l and p and 1 42, 030,221 2.71 54, 041.372 16.83 106,172,671 32,77 8.151100 O., 045 0.124 0.17 26.6 73.4 100 0.03 0.078 27.7 72.3 0.1085 100 Wednesday  T Propane + methyl acetylene + allen Amount C Amount C - CL Ethylbenzene Total 0.015 -11.939 0.24.9013.5185 0.112 88.061 0.00313 0.0768 0.0428 0.127,100 4,083 100 100 Table. four Flow 4,083 100 100 Table b Become an expense. Electricity, kWh Par, Gcal Water turnaround, th The total energy consumption of 1 ton of olefins, tons of standard fuel. TVs 6 0.724 0.801 0.889 1.1345 1.2939 0.378 0.424 0.475 0.6311.271 0.224 0.247 0.268 0.297 0.523 0.3327 0.3689 0.40.5246 0.71 0 H I 4 I J 85; ij; III-a  I mN I 1 I I -. $ {I gJLi 1 I I S K /. . 1 I 11 I lil i i roll i i A  CN / t 7G ..c: be c & 1 I I - I I S S /. . Have 1 I I 11 I r: s   I i i i and o -I CO a J