RU2360897C1 - Method for purification of liquid hydrocarbons from water solution of methanol - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention includes the primary methanol separation on the hydrophilic ultrafine or superfine fiber up to the residual methanol concentration no more than 250 mg/l of the liquid hydrocarbons, extraction of the methanol from liquid hydrocarbons with water, separation of the water solution of methanol from liquid hydrocarbons, removal of the purified hydrocarbons and water solution of methanol, if necessary the removal of the residual water solution of methanol from liquid hydrocarbons with sorption and following desorption and/or catalytical conversion obtaining hydrocarbons and water.

EFFECT: decrease of the energy consumption and efficiency increase in the process of liquid hydrocarbons purification from water methanol solution.

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Description

The invention relates to methods for purification of hydrocarbon mixtures and can be used in the extraction, preparation and processing of hydrocarbon raw materials.

The known method (RF Patent No. 2286194, IPC: B01D 17/038) purifies liquid hydrocarbons from methanol in the form of an emulsion, including heating the emulsion, separation by separation of the heated emulsion into liquid hydrocarbons and an aqueous solution of methanol, and their subsequent separate tap.

The disadvantage of the described method is the high energy costs for heating the emulsion and the low efficiency of the separation process due to poor deposition of an aqueous solution of methanol in liquid hydrocarbons, the light components of which evaporate and / or boil when heated.

The method of purification of liquid hydrocarbons from methanol, which is described in the abstract of the report of Siebert G.K., Klyuiko V.V., Lanchakova G.A., has higher efficiency. and Kulkova A.N. Creation and implementation of new technological processes and equipment based on domestic research and development for LLC Urengoygazprom // Materials of the scientific and technical conference "Ensuring the Effective Functioning of the Urengoy Oil and Gas Complex -M .: LLC IRC Gazprom 2004, p.107 .

This method involves the removal of methanol from liquid hydrocarbons by extraction with water, the subsequent separation of the residual aqueous methanol solution on coalescing filters from liquid hydrocarbons, and the separate removal of the purified hydrocarbons and the aqueous methanol solution after extraction and separation.

The disadvantage of this method is the high consumption of water for extraction, high energy intensity, which is due to the need for further separation of methanol from the aqueous solution obtained by extraction. Moreover, the better the extraction, the greater the energy cost of methanol extraction. In this regard, when implementing this method, the water consumption for extraction is reduced, deliberately leaving a large amount of an aqueous methanol solution in the liquid hydrocarbons being purified.

The problem to which the invention is directed, is to reduce energy costs and increase the efficiency of the process of cleaning liquid hydrocarbons from an aqueous solution of methanol.

The technical result in the implementation of the invention is achieved by the fact that in the method of purification of liquid hydrocarbons from an aqueous methanol solution, including extraction of methanol from liquid hydrocarbons with water, subsequent to extraction, the separation of an aqueous solution of methanol from liquid hydrocarbons, the removal of purified hydrocarbons and an aqueous solution of methanol after extraction and separation, before extraction, primary separation is carried out on a hydrophilic ultrathin or superthin fiber to a residual methanol concentration of not more than 250 m per liter of liquid hydrocarbons, followed by separation of the residual aqueous solution of methanol from liquid hydrocarbons, if necessary, removed by sorption with a subsequent desorption or (ii) catalytic conversion to obtain hydrocarbon and water.

The removable aqueous methanol solution is separated by distillation into methanol and water, which is used in the extraction.

Carrying out preliminary separation before extraction with a hydrophilic ultrafine or superthin fiber to a residual methanol concentration of not more than 250 mg per liter of liquid hydrocarbons allows further extraction with a minimum water consumption and low energy consumption for the subsequent extraction of methanol from the aqueous solution.

Removal of the residual aqueous methanol solution from the hydrocarbon condensate by sorption followed by desorption or (and) catalytic conversion to produce hydrocarbons and water improves the efficiency of purification of liquid hydrocarbons so that the residual methanol content in the hydrocarbon liquid becomes less than 13 mg / L.

Separation using hydrophilic ultrafine and superthin fibers allows the purification of liquid hydrocarbons with a desired residual concentration of 250 mg / l or less.

Removal by sorption or (and) catalytic conversion of a part of the residual aqueous methanol solution allows not to exceed energy expenditures upon reaching the necessary and sufficient efficiency of the degree of purification.

The separation of an aqueous solution of methanol by distillation into methanol and water, which is then used in the extraction, reduces the energy cost of removing salts from the water before extraction.

From the existing level of technology, the authors are not aware of methods for purifying liquid hydrocarbons from an aqueous solution of methanol, in which due to the above characteristics, the efficiency of cleaning liquid hydrocarbons from an aqueous solution of methanol is increased and energy costs are reduced.

Figure 1-9 presents the process flow diagrams of plants for implementing the method of purification of liquid hydrocarbons from an aqueous solution of methanol.

Installation cleaning liquid hydrocarbons from an aqueous solution of methanol, shown in figure 1, consists of:

- a primary separator 1, which has a line 2 for introducing an initial mixture of liquid hydrocarbons (for example, stable or unstable hydrocarbon condensate or oil fractions) and an aqueous solution of methanol, cartridges 3 from a coalescing hydrophilic ultrathin or superthin fiber (for example, uvot sound absorbing products from superthin fiber according to TU 21-5328981-07-92), lines 4 and 5, respectively, of the output of previously purified liquid hydrocarbons and an aqueous solution of methanol;

- extractor 6, connected to line 4 from the separator 1, the input line 7 of water, lines 8 and 9, respectively, the output of the purified liquid hydrocarbons and an aqueous solution of methanol;

- a separator 10 connected to line 8 from the extractor 6 and having cartridges 11 of coalescing hydrophilic ultrathin or superthin fiber, drain lines 12 and 13, respectively, of purified liquid hydrocarbons and an aqueous solution of methanol;

- collector 14, to which are connected the lines 5, 9, 13 of the output of an aqueous solution of methanol from separator 1, extractor 6 and separator 10.

The installation for cleaning liquid hydrocarbons from an aqueous methanol solution, shown in Fig.2, in addition to the separators 1, 10 and extractor 6 contains a system 15 for adsorption removal of the residual aqueous solution of methanol from liquid hydrocarbons. The system 15 consists of two adsorbers 16 and 17. The adsorbers 16 and 17 are connected to the line 12 from the separator 10 and to the line 18 of the removal of purified liquid hydrocarbons. In addition, the adsorbers are connected to a desorption unit — the removal from them of an absorbed aqueous methanol solution. The desorption unit includes lines 19 through which alternately from adsorbers 16 and 17 a mixture of vapor of an aqueous solution of methanol separated from the adsorbent when it is heated and circulating gas is supplied. In addition, it includes a recuperative heat exchanger 20, a refrigerator 21, a separator 22, which is connected to a line 23, through which an aqueous solution of methanol is discharged to the collector 14, a gas pipeline 24, a compressor 25, a heater 26 connected to the adsorbers 16 and 17.

The installation for cleaning liquid hydrocarbons from an aqueous methanol solution, shown in Fig. 3, in addition to separators 1, 10 and extractor 6, contains a system 27 for the absorption removal of the residual aqueous methanol solution from liquid hydrocarbons. System 27 consists of an absorber 28 connected to a liquid hydrocarbon removal line 12 from the separator 10 and to a liquid hydrocarbon removal line 29 removed by a line 30 to a separator 31, which is connected to a liquid line 32 by a liquid hydrocarbon output line 32 to a saturated adsorbent line 33 it is connected to the recuperative heat exchanger 34 and the stripper 35. The desorber 35 is connected to the vapor recovery line of methanol aqueous solution 36 and to the line 37 through the pump 38 and the recuperative heat exchanger 34 to the absorber 28. The desorber is equipped with a heater 39. Desorber 35 is connected by a line 36 to a methanol rectification unit 40 from an aqueous solution. In the installation 40, the line 36 is connected through a recuperative heat exchanger 41 to a distillation column apparatus 42. The distillation column apparatus 42 is equipped with a heater 43, a refrigerator 44, a reflux tank 45, which is connected to the concentrated methanol discharge line 46. The bottom part of the distillation apparatus 42 is connected to the water drainage line 47 through a pump 48 and a regenerative heat exchanger 41.

The installation for cleaning liquid hydrocarbons from an aqueous methanol solution, shown in Fig. 4, in addition to separators 1, 10 and extractor 6, contains a system 49 for removing residual aqueous methanol from liquid hydrocarbons by catalytic conversion. System 49 comprises a methanol catalytic conversion reactor 50 to produce hydrocarbons and water. The reactor 50 is equipped with a heater 51 and a coolant circulation system 52. The inlet of the reactor 50 is connected to the nozzle 12 of the separator 10 through a recuperative heat exchanger 53. The outlet of the reactor 50 is connected by a product line 54 through a recuperative heat exchanger 53 and a cooler 55 with a three-phase separator 56. The three-phase separator 56 is connected to the exhaust lines, respectively, 57 gaseous hydrocarbons, 58 liquid hydrocarbons, 59 water.

The installation for cleaning liquid hydrocarbons from an aqueous methanol solution, shown in Fig. 5, in addition to separators 1, 10 and extractor 6, contains a methanol rectification unit 40 from an aqueous solution, which is connected to a collector 14 of an aqueous methanol solution, and a water drainage line 47 is connected through line 7 with extractor 6. The installation for the purification of liquid hydrocarbons from methanol, shown in Fig.6, consists of the installation shown in Fig.2, and installation 40 for rectification of methanol from an aqueous solution. The units are interconnected as follows: by a collector 14 through a recuperative heat exchanger 41 with a distillation column apparatus 42, lines 47, 60, 7 with an extractor 6. The unit has water discharge lines 61 and removal of purified liquid hydrocarbons 62. In addition, the line 18 of purified liquid hydrocarbons connected to line 62.

The installation for cleaning liquid hydrocarbons from an aqueous methanol solution, shown in Fig. 7, is an upgrade of the installation shown in Fig. 3 by additionally supplying it with water discharge lines 61 and removing liquid hydrocarbons 62, connecting the extractor 6 and the distillation column apparatus 42 with lines 47 and 60, connecting the collector 47 through a recuperative heat exchanger 41 to the distillation column apparatus 42, connecting the refined liquid hydrocarbon line 29 to the line 52.

The installation for cleaning liquid hydrocarbons from an aqueous solution of methanol, shown in Fig. 8, is a modernization of the installation shown in Fig. 4 by additionally supplying it with water discharge lines 61 and removing liquid hydrocarbons 62, connecting the three-phase separator 56 with line 59 through pump 63 and line 60 with an extractor 6, connecting the line 58 of the removal of liquid hydrocarbons to line 62 and connecting the line 57 of gaseous hydrocarbons to the heater 51 for burning the latter.

The installation for the purification of liquid hydrocarbons from an aqueous methanol solution shown in FIG. 9 is a combination of the plants shown in FIG. 8 and a methanol rectification unit 40 from an aqueous solution. In the installation (Fig. 9), the collector 14 is connected through a cooler 55 made in the form of a recuperative heat exchanger, a recuperative heat exchanger 41 with a distillation column apparatus 42, water discharge lines 47 and 59, respectively, from the still part of the distillation column apparatus 42 and a three-phase separator 56 are connected .

The implementation of the proposed method for the purification of liquid hydrocarbons from an aqueous solution of methanol is illustrated by the following examples.

Example 1

The flow rate of the initial mixture is 13150 kg / h (22.4 m ³ / h). The consumption of hydrocarbon condensate is 13069.8 kg / h. The temperature of the initial mixture is 40 ° C, its pressure is 10.5 MPa. The content of an aqueous solution of methanol in the mixture is 0.61 wt.%. Accordingly, the flow rate of an aqueous methanol solution is 80.215 kg / h. An aqueous solution of methanol contains 75 wt.% Methanol, 25 wt.% Water. Accordingly, the consumption of methanol is 56.04 kg / h, water - 18.681 kg / h. The concentration of methanol 2501 mg / L. The concentration of water is 834 mg / l.

Cleaning is carried out in the installation shown in figure 1.

The initial mixture of hydrocarbon condensate and an aqueous methanol solution is fed via line 2 to the separator 1. It is used for primary separation in cartridges on a hydrophilic ultrafine fiber to a residual methanol concentration of 247 mg per liter of mixture. The concentration of an aqueous solution of methanol in the mixture is 329 mg / L. The flow rate of an aqueous solution of methanol in this mixture is 80.215 kg / h. The initially purified mixture (13077 kg / h) of condensate (13069.8 kg / h) and an aqueous solution (7.3 kg / h) is fed from separator 1 via line 4 to extractor 6. An aqueous solution of methanol (73 kg / h) from the separator 1 is removed through line 5 to the collector 14.

In the extractor 6, the condensate is washed in countercurrent with water having a temperature of 30 ° C. Water with a flow rate of 200 kg / h is fed through line 7.

The mixture purified in extractor 6 (13080.245 kg / h) contains 0.04 wt.% Aqueous methanol (5.23 kg / h), which contains 92% water and 8% methanol. After extraction, the concentration of methanol in the mixture is 18.81 mg / L. The mixture after the extractor 6 is fed through line 8 to the separator 10.

An aqueous solution of methanol withdrawn from the extractor 6 through line 9 with a flow rate of 196.755 kg / h contains 87.39% water and 12.61% methanol.

In the separator 10, an aqueous methanol solution is separated from the mixture, which at a flow rate of 1.6 kg / h is discharged via line 13 to the collector 14. The residual content of the aqueous methanol solution in the purified mixture is 163 mg / l. In the purified mixture, the concentration of methanol is 13.0 mg / l (0.29 kg / h), the water concentration of 138.0 mg / l (3.34 kg / h). The purified mixture with a flow rate of 13078.645 kg / h is discharged along line 12 from the separator 10.

Collector 14 removes an aqueous solution of methanol with a flow rate of 271.355 kg / h, which contains 30.84% (83.688 kg / h) of methanol and 69.16% (187.667 kg / h) of water.

Compared with the closest analogue, the cost of water, and therefore the cost of energy, for extraction is 10 times less.

Example 2

Deeper purification of hydrocarbon condensate from methanol, i.e. a decrease in the residual concentration to 1-2 mg / l is carried out by adsorption in the installation shown in figure 2.

The residual aqueous solution of methanol from the mixture supplied through line 12 is absorbed by the adsorbent silica gel in adsorbers 16 and 17, which work alternately for absorption and desorption. The purified hydrocarbon condensate with a methanol content of 1-2 mg / l is removed through line 18.

The absorbed aqueous methanol solution during desorption is removed from the separator 22 through line 23 to the collector 14.

Example 3

Deep purification of hydrocarbon condensate from an aqueous solution of methanol, i.e. a decrease in the residual concentration to 1-2 mg / l is carried out by absorption in the installation shown in figure 3.

A mixture of condensate and an aqueous solution of methanol is fed through line 12 to the absorber 28, which also contains absorbent - diethylene glycol. In the absorber 28, diethylene glycol absorbs an aqueous solution of methanol from the mixture. The purified condensate is removed from the absorber via line 29, and the saturated diethylene glycol via line 30 to the separator 31. In the separator 31, condensate is removed from the saturated diethylene glycol. The latter is diverted via line 32 to line 29. Saturated diethylene glycol is fed through a recuperative heat exchanger 34 to stripper 35. In stripper 35, diethylene glycol is regenerated. Concentrated diethylene glycol is pumped through pump 38 through a recuperative heat exchanger 34 through line 37 to the absorber 28. The methanol aqueous solution from the stripper 35 is withdrawn through line 36 through a recuperative heat exchanger 41 to a distillation column apparatus 42. In the apparatus 42, the methanol aqueous solution is separated into methanol and water. Methanol (97%) after cooling in the refrigerator 44 is discharged from the reflux tank 45 via line 46, and the water pumped by the pump 48 through the recuperative heat exchanger 41 is removed via line 47.

Example 4

Complete purification of hydrocarbon condensate from an aqueous solution of methanol is carried out by catalytic conversion in the installation shown in figure 4.

A mixture of condensate and an aqueous solution of methanol is fed through line 12 through a recuperative heat exchanger 53 to a reactor 50. In a reactor 50 at a temperature of 220-450 ° C, a catalyst containing metals: zinc, copper, chromium, converts methanol to water and hydrocarbons. Their mixture from the reactor 50 is fed through line 54 through a recuperative heat exchanger 53 and cooler 55 to a three-phase separator 56. From the three-phase separator, gaseous hydrocarbons are discharged through line 57, liquid hydrocarbons are discharged through line 58, and the oxen through line 59.

Example 5

In order not to exceed the energy consumption for cleaning, when the degree of purification is achieved by the sorption and / or catalytic conversion, a part of the residual aqueous methanol solution is removed from the condensate, and the other part is removed along with the condensate along line 62 (Figs. 6, 7, 8 ) to the consumer. The purified condensate is removed through line 18 (FIG. 6) from the adsorption purification unit 15, along line 29 (FIG. 7) from the absorption purification unit 27, along line 58 (FIG. 8, 9) from the purification unit 49 by catalytic conversion and fed to line 62.

Example 6

In order to separate water from methanol and reuse it, the aqueous methanol solution removed through collector 14 is subjected to rectification in unit 40 (FIGS. 5, 6, 7, 9).

An aqueous solution of methanol is supplied through a collector 14 through a recuperative heat exchanger 42 to a distillation column apparatus 42, in which the aqueous methanol solution is separated into methanol and water. Methanol (97%) after cooling in the refrigerator 44 is discharged from the reflux tank 45 via line 46, and the water pumped by the pump 48 is removed through line 47 through a recuperative heat exchanger 41. The removed water is used in extraction, for which it is supplied from line 47 via line 60 to line 7 and extractor 6.

Thus, the proposed method for the purification of liquid hydrocarbons from an aqueous menthol solution allowed to reduce energy costs and increase the efficiency of the process of purification of liquid hydrocarbons from methanol.

Claims (2)

1. The method of purification of liquid hydrocarbons from an aqueous solution of methanol, including the extraction of methanol from liquid hydrocarbons with water, subsequent to extraction, the separation of an aqueous solution of methanol from liquid hydrocarbons, the removal of purified hydrocarbons and an aqueous solution of methanol after extraction and separation, characterized in that prior to extraction, primary separation on a hydrophilic ultrafine or superthin fiber to a residual methanol concentration of not more than 250 mg per liter of liquid hydrocarbons, followed by separation its residual aqueous solution of methanol from liquid hydrocarbons, if necessary, is removed by sorption followed by desorption or (and) catalytic conversion to produce hydrocarbons and water. 2. The method according to claim 1, characterized in that the removed aqueous solution of methanol is separated by distillation into methanol and water, which is used during extraction.

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