SU1070149A1 - Process for deparaffination of distillate petroleum products - Google Patents

Description

i

The invention relates to the oil refining industry, in particular, to a method for dewaxing distillate petroleum products with urea, and can be used in factories that have distillate petroleum products in the plant dewaxing scheme.

The known method. The dewaxing of petroleum products of crystalline urea 11,

The disadvantages of the dewaxing method with crystalline urea are the duration of the contacting phases during complexation, the difficulty of removing heat from the reaction mixture, the complexity and unreliability of the equipment used, the deposition of urea in the apparatus and the pipe. wires, fast loss of carbamide activity and the use of toxic substances.

Also known is the process of dewaxing petroleum products in a spirit-water solution of urea.

According to this method, the raw materials are mixed with a certain amount of a spirtovododny solution of urea. The complexation is carried out in heat exchanger reactors with a gradual cooling of the reaction mixture. Cooling is done with water,

After separation of the dewaxed fuel, the complex suspension is decomposed

The isolated solution of paraffins after the removal of alcohol is directed to the rectification with the purpose of separating the prohMBHoi-i fraction and obtaining the desired paraffins, the washing fraction is regenerated and the vng is returned to the washing stage of the complex.

Alcohol from the dewaxed oil product and paraffins is washed with water, 3 (E. tem is subjected to azeotropic distillation and strengthened. After strengthening, the filter is introduced with raw materials for dewaxing, C 2.

The disadvantage of this method is the greater energy intensity and metal intensity of the reactor unit, due to poor heat exchange in tubular reactors, heat exchangers due to the deposition of urea and the Complex on the walls of the tubes. Poor heat exchange also necessitates the periodic shutdown of the reactors for heating, which leads to a decrease in the installation efficiency, a decrease in the contact time of the reaction mixture.

The closest to the proposed method is the dewaxing of petroleum products using concentrated solutions of carbamide, methylene chloride as a solvent, and methanol as activated C31.

Way Osu1: These are:

A deparade5, a finished oil product, and a solution of urea with complex coagulation are fed into the stirring reactor in reactors (7.ri steps), where the heat of the exothermic reaction and cooling of the reaction mixture 0 is removed by evaporating dichloromethane under vacuum. Condensed vapors of dichloromethylene are not poured into the evaporation zone, but through scrubbers, compressors, respective collectors are fed to the regeneration, and then dichloromethylene is sent to the initial stage of the process for mixing. Since the evaporated dichloromethylene does not expand to the evaporation zone, in subsequent reactors the viscosity of the reaction mixture increases, the contact of the phases deteriorates, and consequently, the degree of paraffin recovery decreases. 5 The disadvantages of this method also include the use of toxic substances: dichloromethylene and methanol.

The purpose of the invention is to improve the quality of dewaxing products. The goal is achieved by the fact that according to the method of dewaxing distillate petroleum products by mixing them with a solution of urea in an organic solvent to form a complex of paraffins with urea under step evaporation and condensation of the solvent, 70-90 May „% of the condensed solvent is returned to the 0 evaporation stage, 10 -30% by weight of the remaining solvent is fed to the next-stage evaporation stage and, at the last stage, the condensed solvent is returned to the same level. 5 As a result, the optimum viscosity of the reaction mixture is maintained while it is cooled, as well as a high concentration of alcohol, since at each stage of complexing, the condensed alcohol from the previous reactor is fed to the reaction mixture.

The method is carried out as follows.

- Raw materials, saturated with alcohol, are mixed with urea solution, cooled to 55-50 ° C and fed to the first stirred reactor, the residual pressure of which is 200 mm Hg, Art. The temperature of the reaction mixture due to evaporation of the solvent is 50 ° C. Vacuum is created using a vacuum pump. Solvent vapors enter the refrigerator, condense, 70-90 wt.%

5 from the evaporated solvent, returned to the reactor; the remaining 10-30 May, the evaporated solvent was introduced through the valve, automatically connected to the flow regulator, to the second reactor. From the top of the first reactor, the reaction mixture goes to the bottom of the second reactor, the residual pressure of which is 110 mm Hg, the temperature of the reaction mixture due to the evaporation of alcohol 42 ° C. Alcohol vapors from the second reactor enter the cooler, condense, 70-90 wt.% Return to the reactor, 10-30 wt.% Through the valve of the automatic flow regulator are fed to the third reactor. The reaction mixture from the top of the second reactor enters the bottom of the third reactor, the residual pressure in which is 75 mm Hg. Art. The temperature of the reaction mixture was 34 ° C. Alcohol vapors from the third reactor, after cooling and condensation, completely return to the reactor. The reaction mixture from the top of the third rotor is pumped to a sump, where the dewaxed product is separated from the complex. The complex is subjected to a three-stage counter-flow washing. The washed complex is decomposed at b5-70 ° C. The depleted solution and paraffins are separated by sediment. The alcohol is washed from the paraffin solution and the dewaxed fuel in Doy, followed by azeotropic distillation in two stages. After washing the isopropyl alcohol from the paraffins, the washing liquid is distilled off on a vacuum column. Paraffin is removed from the bottom of the column as a finished product. Example 1 The dewaxing is subjected to the following quality distillate oil: Density, 8440 Boiling range, ° C 300-400 Pour point, ° C-18 Viscosity at 50 ° C, cSt 6.2 Flash point, C 144 Dewaxing used I solution the content of urea is 35% by weight and isopropyl alcohol is 65.5% by weight (alcohol concentration 7S% Conditions of complex formation and material flows through the reactors: I reactor Residual pressure, mm Hg, st. 180-190 Temperature, ° С52-55 Income,% Reaction mixture: raw materials25.1 solution 72.7 Condensed alcohol from conde Step Step2.2 Consumption,% Reaction mixture: raw materials 25.1 solution71.7 Alcohol vapors to condenser 3, 1 II Reactor Residual pressure, mm Hg. Art. 110-120 Temperature, ° С43-40 Parish,% Reaction mixture: raw material 25.1 solution71 , 8 Condensed alcohol from condenser Step 0.9 Condensed alcohol from condenser Step 2,2 Consumption,% Reaction mixture: raw materials 25.1 solution, 71.8 Alcohol vapors to condenser 3, 1 III Reactor Residual pressure, mm Hg. Art., 75-80 Temperature, C32-35 Income,% Reaction mixture: raw materials 24.9 solution71.1 Condensed alcohol from condenser II stage0, 9 Condensed alcohol from condenser III stage 3, 1 Consumption,% Reaction mixture: solution Alcohol vapors to condenser qualitative characteristics of depot oil and paraffins:) Dewaxed oil, pour point, ° C Kinematic viscosity, cSt, at 50 ° C Flash point, ° C) Paraffin Content of impurities,% 0.47 Pour point, ° С30 Example 2. Deparaffinization is subjected to diesel fuel steam The quality of the oil is as follows: Density pf0.7968 Fractional composition, С НК178 10% 201 50% 341 90% 310 96% 318 КК323 Viscosity at, сСт3.05 Flash point, ° С66 Cloud temperature, С -10 Pour point, C-15 The content of complexing hydrocarbons, wt.% 35.4 In this example, 30 wt.% Of the evaporated alcohol from one stage are fed to the next stage, and 70 wt.% Are returned to the evaporation zone. In the Dewaxing process, a solution with a content of urea of 40 wt.% And isopropyl alcohol of 60% with a concentration of 70% is used. Dewaxing conditions The ratio of the amount of urea solution and raw materials: when the content of urea is 40 wt.% And the alcohol concentration is 70% 4.5: 1 Temperature in the reactor block, C: initial 65-60 final 35-30 At the last stage, the condensed alcohol is returned to the same evaporation stage. Example 3. The same raw materials are subjected to dewaxing as in Process 2, the same complex conditions are formed, only from the evaporated line to the next stage 1 ndensirovannogo alcohol is fed, 90% is rotated to the evaporation zone, on the ice stage all evaporated mouth is returned to same stage arena. The quality characteristics of the depenated fuel and the material balance by examples 2 and 3 are as follows: Indicators2 3 Density f 0.8101 0.8096 Fractional composition, ° C NC 10% 50% 90% 95% QC Viscosity, cSt Flash point, ° C 61 60 Temperature -35 n / a -35 turbidity, ° C Pour point, ° C Material balance, wt.% For raw materials: Dewaxed product Paraffins (commercial with aromatic hydrocarbon content 0.5 wt.%) 25.8 Intermediate fraction and loss of 10 V The table shows the characteristic characteristic of a product that is fully known and offered by sobs. The proposed method compared to the rototype provides the support of the optimal viscosity of the reaction mixture and concentration (dissolves the quality of the dephinization products, increases the yield of deposits and reduces energy consumption.

Low-temperature properties of the dewaxed fuel:

cloud point, ° C

pour point, s

-35

-35 -46 -60

Paraffins:

output from potential, wt.%

the content of aromatic hydrocarbons, wt.%

Table continuation

84

76

60

0.36

0.22

1.2

Claims (1)

and solvent condensation, characterized in that, in order to improve the quality of petroleum products, 70-90 wt.% of the condensed solvent is returned to the evaporation stage, 10-30 wt.% of the remaining solvent is fed to the next evaporation stage and at the last stage, the condensed solvent is returned to the same step.