Method of separating c5-hydrocarbon fractions

FIELD: petroleum processing and petrochemistry.

SUBSTANCE: C5-hydrocarbons with different degrees of saturation are separated by extractive rectification in extractive rectification column using dimethylformamide as extractant followed by desorption of pentenes or pentadienes therefrom and passing desorbed extractant to extractive rectification column. Part of hot desorbed extractant is subjected to liquid-phase mixing with starting hydrocarbons at vigorous stirring, after which resulting mixture is introduced into column in liquid form.

EFFECT: reduced power consumption.

2 dwg, 1 tbl, 5 ex

 

The invention relates to the separation of hydrocarbon, C5different degrees of saturation, in particular pentane, pentanol and pentadiene contained in the fractions of different origin (dehydrogenation, pyrolysis of hydrocarbons, etc.), in the presence of a polar organic extractants and can be widely used in the synthetic rubber industry in the production of the basic monomer is isoprene.

There is a method of separating hydrocarbon, C5obtained by the dehydrogenation of hydrocarbons by successive separation from the target hydrocarbon fraction of light (C1-C4) and heavy (C6and higher) hydrocarbons by distillation, followed by separation of isoamylenes and / or isoprene) by extractive distillation [1].

Closest to the invention to the technical essence is a method of separating hydrocarbon, C5consisting in the separation of light and heavy hydrocarbons in the columns of a conventional rectification and separation of the residue in the presence of a polar organic solvent (dimethylformamide) by two-stage extractive distillation (E.R.) and desorption [2]. Thus obtained C5faction: isopentane - isoamylene after the first stage dehydrogenation is directed to the separation by extractive distillation.

The isopentane - ITA Elenovo faction divided into isopentane, return to the first stage dehydrogenation, and isoamylenes fraction directed to the second stage dehydrogenation. Isoamylene - isoprene fraction divide a return isoamylene returned to the second stage dehydrogenation, and isoprene sent to the treatment plant. The content of isoamylenes in return isopentane is 1.8 wt.%, and the content of isoprene in return isoamylene up to two wt.%. The concentration of the extractant (DMF) on the plates at both stages E.R. 60-80 wt.%.

Due to the high concentration of the extractant temperature in cubes columns reaches 100 or more °With that in combination with the use of hydrocarbon recycle leads to the formation of thermopolymeric (the formation of which begins on the surface of the condensing liquid) [3], as well as to need to use for heating cubes columns of steam at high temperature.

The AIM of the INVENTION IS:

Reducing energy consumption and improving the efficiency of the separation process due to a change in the method of heating source of hydrocarbon fractions C5.

This objective is achieved in that part of the hot desorbed solvent (DMF) with a temperature of at least 124°mix with the initial fraction With the5in the liquid state at a ratio of 3.0:1.0 in the first and second stage E.R. intensively when the stirring of the resulting mixtures under pressure 6-6,5 ATA before entering the column. Missing to 4-8:1 raw materials DMF is served on the top of the columns.

In the production division of fractions of hydrocarbons, C5use the method of heating and evaporation of hydrocarbons in heat exchangers with water vapor, the lack of which is the deposition of polymers on the tubes of the apparatus and the necessity of their removal by reducing the effectiveness of their work.

The method of heating and evaporation of the hydrocarbon, C5hot desorbed by solvent DMF in heat exchangers has three drawbacks, as on the walls of the heat exchangers on the one hand is the deposition of resins from the extractant, and the other deposition thermopolymeric from raw materials with increased heat exchange surface, which further complicates the problem of cleaning heat exchangers (evaporators).

The most effective is the proposed method of heating the raw material in which the secondary heat hot desorbed solvent DMF is used in a greater degree, allowing you to completely eliminate the use of steam for heating and evaporation of raw materials and equipment-evaporators. The proposed method is devoid of the drawbacks of the methods of heating the raw material, and is as follows.

(Heating without evaporation to enter in column) initial fraction of hydrocarbons With5you must apply for direct mixing (liquid - liquid) with th is Achim extractant DMF. Raw materials must be submitted to the mixing cone through the cylinder, equipped with a large number of holes with a diameter up to 4 mm (since the raw material is always cleaner than the extractant DMF). Extractant for heating the source of hydrocarbon fractions With5must be made in such quantity that the temperature of the mixture formed was within 100°and equals the amount of heat introduced into the column of vaporized raw material. However, due to the intensive mixing of the liquid mixture will process liquid extraction under pressure to 6.5 ATA and a large part of the original hydrocarbon fractions With5is associated with the extractant DMF.

According to the nature of the saturability of DIMETHYLFORMAMIDE pentadiene stand in front of pentanol and pentene stand in front of pentane and when entering the liquid mixture in the column E.R. and reducing the pressure to 2 ATA and below evaporate first start those components of the hydrocarbon, C5that have a coefficient of relative volatility is greatest, i.e. it turns out that in the vapor phase on the plate of the input mixture in the columns E.R. first stage contains fewer pentanol and columns E.R. second stage in the vapor phase above the plates of the input contains fewer pentadiene, which leads to loss reduction [4-6].

In Fig. 1 and 2 presents the scheme before aguinaga method.

EXAMPLE 1

To determine the necessary amount of heat for heating 500 grams of hydrocarbons With a5to 100°and the required amount of extractant DMF for heating by way of mixing at a temperature of DMF at least 124°C. According to the formula of the heat balance are:

Q=Gx·Cx(t2-t1)-G·IG·(T1-T2),where:

Gx and G - number of heated (cold) and hot liquid, g;

CX and CR is the average heat capacity of hot and cold liquid, cal/g °C;

T1and T2- initial and final temperature of heating fluid, °C;

t1and t2- initial and final temperature of the heated liquid, °C.

Then: Qi=Gi·Ci(t2-t1)=500·0,4·(100-10)=18000 cal.

G2=Qi/C2·(T1-T2)=18000/0,5·(124-100)=1500

EXAMPLE 2

In the apparatus with a capacity of 3 liters is filled with 1500 g of DMF, the mixer is turned on and is heated to a temperature of at least 124°C. the Heating is turned off and the apparatus is introduced 500 g of hydrocarbons With a5the first stage dehydrogenation. Is the stirring of the mixture for three minutes. In the apparatus the temperature of 98°and pressure 4 ATA. When stopped the mixer and three minutes the supernatant is collected liquid sample and the vapor phase is taken to reduce the pressure in the apparatus to 2 ATA. The trap is going to 39.7 g Plevo the cities C 5. The compositions of liquid and vapor phase were analyzed and are summarized in table 1.

EXAMPLE 3

In the apparatus with a capacity of 3 liters is filled with 1500 g of DMF, the mixer is turned on and is heated to a temperature of at least 124°C. the Heating is switched off and placed 500 g of the hydrocarbon, C5the second stage dehydrogenation. Is stirring (60 rpm) mixer for three minutes. In the apparatus the temperature of 100°and the pressure of 3.6 ATA. Without stopping the mixer is selected liquid and vapor phase. In the vapor phase passes 18 g of the product. After stopping the mixer and the pressure decrease up to 2 ATA is collected liquid sample. The compositions of the samples were analyzed and are summarized in table 1.

Thus, the savings of heat and water vapor is the binding of target products in the liquid phase prior to entering into the columns E.R.

EXAMPLE 4

Condensed and highlighted the isopentane - isoamylene fraction is directed to the separation according to the scheme shown in figure 1. Hydrocarbons, C5the first stage dehydrogenation of isopentane on line 1 serves for heating by direct mixing with hot desorbed by solvent (DMF), which is supplied via line 9 to a temperature of at least 124°C. the Obtained liquid mixture in the ratio 1:3 with a temperature of 100°after stirring for line 2 is fed into the column 3 in pocket 18 that is a Christmas tree. 48 (56) plate along the line 4 is fed DMF to rest ratio of 4-6:1 and a temperature of 50°C.

Column 3 has 150 bubble cap trays and operates with a reflux ratio of 1.2. The temperature of the top of the column 44°and in Cuba - 136°C. From the top of column 3 through line 5 select the isopentane content of isoamylenes to 1 wt.%. From the cube column 3 through line 6 select rich penten - pentadiene extractant and served in column 7 on the desorption of DMF. From the top of column 7 through line 8 select penten - pentadiene faction and sent to the second stage separation. From the cube column 7 desorbed extractant DMF again available on line 9 direct mixing with the raw materials in a ratio of 3:1, and the rest of DMF on line 4 goes back to the separation process.

EXAMPLE 5

Condensed and highlighted isoamylene - isoprene fraction of the first stage dehydrogenation and isoamylene - isoprene fraction of the second stage dehydrogenation go in the ratio of 1:2 or 1:1 on division by the scheme shown in figure 2.

Raw material (mixture of poor+rich raw materials in the ratio 1:1) is supplied via line 1 to the heating by way of direct mixing with hot desorbed by solvent DMF in a ratio of 1:3 with a temperature of at least 124°With that comes through the line 9. The obtained liquid mixture in line 2 with a temperature of 100°served in column 3 85 (55) pocket tap the CTL. At a meeting with top, liquid flow, the temperature of the mixture is reduced from 100°to 72°C. To 120 (105) a plate line 4 is extractant DMF to rest ratio with the input raw materials 5-8:1 and a temperature of 50°C. Column 3 has 150 bubble cap trays and operates with a reflux ratio of 1.6.

The temperature of the top of the column 3 is equal to 37°and in Cuba columns to 120°With (depending on feed recycle isoprene). From the top of column 3 through line 5 select pontenova fraction containing isoprene to 0.5 wt.%. From the cube column 3 select rich pentadiene extractant DMF and 6 are directed to the desorption column 7. From the top of column 7 through line 8 select isoprene raw, which is then sent to clear rectification. From the cube column 7 through line 9 output desorbed DMF, which again refer to the process of mixing, heating and link target components of the feedstock, and line 4 to the top of the column 3.

The use of the proposed method of heating the raw material allows you to:

1. Due to a change in the method of heating the feedstock to exclude from the scheme evaporators raw materials and the use of steam for evaporation of raw materials. This leads to saving of thermal energy not only at the stage of evaporation of the raw material, but also on the phase separation in columns E.R.

2. To reduce the loss of isoamylenes with pumped isopentane, and snis the th loss of isoprene with pumped isoamylene both at the stage of heating the raw material, and at the stage of separation in columns E.R.

3. Heating the solvent DMF raw materials new way of direct mixing leads to saturation of the extractant target components of raw material and linking them to input in column E.R., allowing you to raise the plate power higher in the first stage and to reduce the plate supply for the second stage, and also to relieve the columns E.R. excess of the upper medium (flegma) require less energy, which leads to better results.

The sources of information.

1. Ogorodnikov S. Kaliev, Idlis G.C. sec;Production .sec; L.: Chemistry. 1973, p.129.

2. Inventor's certificate SU 803343 A1, 20.12.2000.

3. Copyright certificate №642322, 1979.

4. a) Ogorodnikov S. Kaliev, Kogan CENTURIES, Nemtsov MS sec;the Equilibrium between liquid and vapour mixture of dimethylformamide - isoprene - .sec; ZH 34, №11, 2441 (1961).

b) Karev VG, Baranov A.V. the conference Proceedings of the Siberian technological Institute on the results of work in 1962, Issue 2, Krasnoyarsk, 49 (1963) sec;the Equilibrium between liquid and vapour dimethylformamide-isopentane-sec;.

5. Pavlov CYP, Romankov p. g, Socks, A.A. sec;Examples and problems at the rate of the processes and apparatus of chemical sec;. L.: Chemistry. 1970, S. 212.

6. Pavlov HE and others. The selection of the isoprene fraction of C5pyrolysis gasoline. sec;Chemical .sec; 197, No. 4.

TABLE 1

The COMPOSITIONS of SAMPLES FROM the experience of the No. 1 and EXPERIENCE No. 2 weight%
№p/pName of productSample 1Sample 2Sample 3DMFSample 4Sample 5Sample 6
  Cat. 1 tbsp.DMFTrap 1Desorbed.Cat 2tbsp.DMFTrap 2
  raw materialsrich  raw materialsrich 
1.Hydrocarbons, C40,30,022,79 0,50,09a 3.9
2.Isopentane65,514,8691,4 0,90,0816,3
3.Methyl - buten2,70,680,60 a 3.90,935,9
4.npentane3,10,733,022,80,674,6
5.Penten0,50,120,25 1,80,42a 3.9
6.Methyl - buten8,82,230,63 18,94,4733,3
7.Penten1,90,470,5 4,81,147,3
8.Methyl - buten14,53,690,5 35,88,8322,7
9.Isoprene20,510,2 27,46,91,5
10.1,pentadien0,40,10,1 1,80,450,1
11.Cyclopentadien0,20,050,02 10,25 
12.Hydrocarbons With60,10,02   0,40,1 
13.DMF of 76.52   75,670,5
Value sample500,01960,339,71500,0500,01982,018,0

Method of separating hydrocarbon, C5different degrees of saturation extractive distillation in the column extractive distillation using dimethylformamide as a solvent with subsequent desorption of the last pentanol or pentadiene and flow of desorbed solvent in the extractive distillation column, characterized in that before applying to the column part of the hot desorbed extractant fed to the mixing with the original hydrocarbons, the mixing is carried out in the liquid phase under vigorous stirring and the resulting mixture is introduced into the column in a liquid form.



 

Same patents:
The invention relates to a method of separating a mixture WITH4hydrocarbons by extractive distillation in the presence of the extractant on the basis of acetonitrile and can be used in the synthetic rubber industry, in particular the separation of the cracking butane-butylene fraction (BBF)

The invention relates to a method of purification of benzene from coke production and benzene obtained from fractions of pyrolysis oil from impurities saturated and unsaturated hydrocarbons, thiophene and carbon disulfide

The invention relates to the petrochemical industry, for the purification of benzene, obtained from a liquid hydrocarbon, C6-C7- fractions of pyrolysis oil from impurities unsaturated hydrocarbons

The invention relates to the field of production of benzene and high-octane mixtures

The invention relates to a method of separation of aromatic hydrocarbons from mixtures thereof with non-aromatic methods liquid extraction or extractive rectificatio and can be used in refining and petrochemical industries

The invention relates to the separation of mixtures of lower hydrocarbons

The invention relates to a method for production of pure benzene and pure toluene from the original product containing aromatic hydrocarbons, and the original product in the stabilization process step of distillation (1) free from gases, and stable source product is divided into an intermediate product, enriched with benzene, and the intermediate product, enriched with toluene, and the intermediate product, enriched with benzene, and the intermediate product, enriched in toluene, send in process stage extractive distillation (2) and separately issued on different plates of the column for extractive distillation (4), and a mixture of pure benzene, pure toluene and extracting agent selected from the lower part (3) of the column for extractive distillation (4) and with the extracting agent in the Stripping process stage (5) is separated from pure benzene and pure toluene and return in process stage extractive distillation (2)

The invention relates to the field of chemical technology, and more specifically to a method for allocation of n-hexane from hexasticha gasoline fractions containing the addition of n-hexane blastocytosis to him hydrocarbons: 2.2-Dimethylbutane, 2,3-Dimethylbutane, 2-methylpentane, C-methylpentan, Methylcyclopentane and other paraffin and cycloparaffin Uglevodorody composition C5-C6

FIELD: petroleum processing and petrochemistry.

SUBSTANCE: C5-hydrocarbons with different degrees of saturation are separated by extractive rectification in extractive rectification column using dimethylformamide as extractant followed by desorption of pentenes or pentadienes therefrom and passing desorbed extractant to extractive rectification column. Part of hot desorbed extractant is subjected to liquid-phase mixing with starting hydrocarbons at vigorous stirring, after which resulting mixture is introduced into column in liquid form.

EFFECT: reduced power consumption.

2 dwg, 1 tbl, 5 ex

FIELD: petrochemical processes.

SUBSTANCE: C4-hydrocarbon fractions obtained by cracking and/or pyrolysis of hydrocarbon feedstock in presence of amine-type extractant are subjected to rectification additionally involving butylene-isobutylene fraction resulting from butylene-to-isobutylene isomerization and containing 30-70% butylenes, 25-65% isobutylene, and 3-8% butanes. Weight ratio of C4-hydrocarbon fractions to added butylene-isobutylene fraction is 1:(3-7).

EFFECT: increased separation efficiency.

3 ex

FIELD: petroleum industry.

SUBSTANCE: process in carried out in column having divider arranging in longitudinal direction to form the first section, the second one and the third bottom joint section, wherein extractive scrubber is includes before divider.

EFFECT: simplified technology.

16 cl, 3 dwg

FIELD: petroleum processing and petrochemistry.

SUBSTANCE: catalysate of reforming of long gasoline fractions containing more than 2% benzene is separated by rectification into three fractions: light-boiling fraction containing mainly nonaromatic C4-C6-hydrocarbons and no more than 1%, preferably no more than 0.5%, benzene; high-boiling fraction containing mainly aromatic and nonaromatic hydrocarbons C7 or higher and no more than 1%, preferably no more than 0.5%, benzene; and benzene fraction boiling within a range of 70-95°C and containing no more than 0.1%, preferably no more than 0.02%, toluene and no more than 0.02% nonaromatic hydrocarbons with boiling temperature above 110°C. Benzene fraction is routed into benzene isolation process involving extractive rectification with polar aprotic solvent having ratio of dipole moment to square root of molar volume above 0.3 db/(cm3/g-mole)1/2, preferably above 0.4 db/(cm3/g-mole)1/2, and boiling temperature 150 to 250°C.

EFFECT: improved quality of benzene.

4 dwg, 2 tbl, 5 ex

FIELD: petrochemical processes.

SUBSTANCE: process involves extractive rectification in presence of extractant mainly containing aliphatic N-alkylamide, while toluene is introduced into rectification column point disposed between extractant inlet and the top of column.

EFFECT: reduced loss of extractant with distillate.

6 cl, 3 dwg, 6 tbl, 6 ex

FIELD: petrochemical processes.

SUBSTANCE: invention provides a process flow rate comprising at least (i) zone of extractive rectification in presence of polar extractant to produce distillate mainly containing butanes and butane(s); (ii) desorption zone wherein desorption of extractant gives stream containing mainly 1,3-butadiene and. as impurities, at least 2-butene(s) and acetylene hydrocarbons; and (iii) optionally rectification zone for mainly 1,3-butadiene-containing stream. In the latter, α-acetylene hydrocarbons are subjected to liquid-phase selective hydrogenation with hydrogen or hydrogen-containing mixture in presence of solid catalyst containing metal(s) exhibiting high activity in hydrogenation process, preferably non-precious metal(s) on solid support. Temperature is maintained within a range 5 to 75°C at contact time ensuring hydrogenation of no more then 6%, preferably no more than 2% of butadiene present. After hydrogenation, 1,3-butadiene is optionally additionally separated from impurities via rectification.

EFFECT: simplified process.

13 cl, 3 dwg, 2 tbl, 10 ex

FIELD: industrial organic synthesis.

SUBSTANCE: crude 1,3-butadiene is recovered from C4-fraction by extractive distillation using selective solvent on column separated by a partition installed along longitudinal direction of the column to form first and second subzones and underlying common column zone. The column is connected to preswitched flush column. Distillation column operation is controlled by energy supply with the aid of lower evaporator and distribution of a series of theoretical plates within underlying common zone to create bottom stream therefrom consisting of purified solvent.

EFFECT: simplified process technology.

23 cl

FIELD: petroleum processing.

SUBSTANCE: separation of crude C4-fraction comprises rectification of C4-fraction containing butanes, butenes, 1,3-butadiene, and small amounts of other hydrocarbons, including C4-acetylenes, 1,2-butadiene, and C5-hydrocarbons, via extractive distillation using selective solvent. Crude C4-fraction is fed to middle part of first extractive distillation column and selective solvent is added to column above crude C4-fraction introduction point. Vaporous side stream containing C4-acetylenes together with 1,3-butadiene1,2-butadiene, C5-hydrocarbons, and selective solvent, wherein concentration of C4-acetylenes is below self-decomposition threshold, is withdrawn from the first distillation column from the point below crude C4-fraction introduction point. Top stream containing crude C4-fraction components, which are less soluble in selective solvent than C4-acetylenes, are withdrawn from upper part of the first extractive distillation column.

EFFECT: optimized order of process operations.

21 cl, 1 dwg

FIELD: petroleum processing and petrochemistry.

SUBSTANCE: in particular, invention aims at producing extraction dearomatized component from reformat of gasoline fraction, which component may be used in production of petroleum solvents such as hexane solvents. Process comprising countercurrent extraction of aromatic hydrocarbons with liquid selective extractant to separate dearomatized component (raffinate) and subsequent extractive rectification of resulting extract phase by distilling off aromatic hydrocarbons is characterized by that liquid selective extractant is diethylene glycol or triethylene glycol, countercurrent extraction is carried out at 125-140°C, extractive rectification is carried out using process steam in presence of saturated selective extractant wherein evaporation of water is performed with the aid of energetic steam, unsaturated selective extractant after extractive rectification and recycled gasoline are sent to extraction stage preliminarily using unsaturated selective extractant as heat carrier to generate process steam, and energetic steam condensate is used to heat recycled gasoline to 80-130°C.

EFFECT: enhanced process efficiency.

3 cl, 1 dwg, 1 tbl, 3 ex

FIELD: petrochemical processes.

SUBSTANCE: hydrocarbon mixture obtained by extractive distillation of C4-fraction using selective solvent, which mixture contains those C4-hydrocarbons, which are better soluble in selective solvent than butanes and butenes, is subjected to continuous separation. Mixture is supplied to first distillation column, wherein it is separated into top stream, containing 1,3-butadiene, propine, and, if necessary, other low-boiling components and, if necessary, water, and bottom stream containing 1,3-butadiene, 1,2-butadiene, acetylenes, and, if necessary, other high-boiling components. Proportion of 1,3-butadiene in bottom stream of the first distillation column is controlled in such a way as to be high enough to dilute acetylenes beyond the range wherein acetylenes can spontaneously decompose. Top stream from the first distillation column is passed to second distillation column, wherein it is separated into top stream, containing propine, and, if necessary, other low-boiling components and, if necessary, water, and bottom stream containing pure 1,3-butadiene.

EFFECT: simplified process and reduced power consumption.

4 cl

Up!