RU2353646C1 - Method of oil products de-waxing - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to chemical technology and oil and gas processing and can be implemented for oil products de-waxing and for extracting paraffin hydrocarbon out of them; purpose of invention is increased withdrawal of de-waxed diesel fuel at maintaining indices of low temperature properties of diesel fuel - setting and cloud points. The method of de-waxing of oil products is performed by mixing raw stock with a surface-active substance, by heat treatment of obtained mixture, and by cooling it to the temperature of de-waxing with successive extraction of paraffin hydrocarbons in electrostatic field. A product of interaction of stearic acid, polyethylenpolyamines at weight ratio correspondingly 4.5:1.0 is used as a surface-active substance.

EFFECT: extraction of paraffin hydrocarbons out of oil products at increased output of de-waxed diesel fuel at maintaining indices of low-temperature properties of diesel fuel - setting and cloud points.

2 ex, 1 tbl

Description

The invention relates to the chemical technology of oil and gas processing and can be used for dewaxing of petroleum products and the allocation of paraffin hydrocarbons from them.

The following methods for dewaxing oil products are common in the oil refining industry: dewaxing oil products on vacuum filters using low-temperature crystallization of paraffin hydrocarbons in ketone-aromatic solvents [Bogdanov N.F. et al. Dewaxing of petroleum products. M .: Gostoptekhizdat, 1961, p.186-188]; dewaxing of oil products by filter pressing and sweating of gach using crystallization of paraffin hydrocarbons without the use of solvents [Pereverzev AN and others. Production of paraffins. M .: Chemistry, p. 161-164]; carbamide dewaxing [Usachev V.V. Urea dewaxing. M .: Chemistry, 1967, p.114-117], dewaxing on zeolites [Akhmetov S.A. Technology of deep processing of oil and gas. Ufa: Gilem, 2002, p.321].

There is also a method of dewaxing oil products by mixing raw materials with a surfactant, heat treatment of the resulting mixture, cooling it to a dewaxing temperature, homogenizing and keeping the cooled mixture followed by the release of paraffin hydrocarbons on electrodes in a constant electric field. As a surfactant, a condensation product of synthetic fatty acids of fraction C _21-25 and polyethylene polyamines is used in a weight ratio of 5.5: 1.0, respectively (Pat. RF 2106390, 6 C10G 73/30. Method for dewaxing petroleum products. Publish. March 10, 1998 Bull. No. 7).

The disadvantage of this method is the low degree of separation of solid paraffin and liquid low-solid hydrocarbons of petroleum products, as well as a low yield of dewaxed petroleum products.

The task to be solved by the claimed method is aimed at increasing the yield of dewaxed diesel fuel. The problem can be solved by achieving a technical result, which consists in increasing the yield of dewaxed diesel fuel while maintaining indicators of low-temperature properties of diesel fuel - pour point and cloud point.

The specified technical result is achieved by the fact that the dewaxing of petroleum products is carried out by mixing raw materials with a surfactant, heat treatment of the resulting mixture, cooling it (mixture) to a dewaxing temperature, followed by isolation of paraffin hydrocarbons on the electrodes in a constant electric field using a polyamide depressant additive as a surfactant, which is the condensation product of stearic acid (SC) with polyethylene polyamines (PEPA) at a mass ratio of the starting reagents, respectively, 4.5: 1.0 ( al. RF 2289613 C1, C10L 1/22, S10M 133/04, C10N 30/02. A method for producing depressant for petroleum products. Publ. 20.12. 2006 Bulletin. №35).

The method is as follows.

0.05-0.15 wt.% Polyamide depressant additives (surfactants) are introduced into the paraffinic oil product. The mixture of raw materials and surfactants is subjected to heat treatment at a temperature above the cloud point of the mixture, preferably at 60-70 ° C until the depressant additive is completely dissolved. Next, the mixture is poured into a bronze cell for electrodeparaffinization, which is a system of coaxial electrodes of the prototype. To prevent electrical breakdown, the bottom of the cell is made of a dielectric - fluoroplastic. Cell dimensions: outer diameter of the inner electrode 15 mm, inner diameter of the outer electrode 30 mm; the height of both electrodes is 20 mm. The interelectrode distance is 7.5 mm. The bronze cell is placed in a thermostatic glass chamber with double walls, between which kerosene circulates as a refrigerant. The thermostatically controlled chamber has a glass lid. The glass chamber and lid have a sealed connection on the thin section. Cold kerosene with temperatures up to minus 17 - minus 18 ° С is fed into the jacket of the glass chamber from the low-temperature cryostat of the Lauda E 100 company with remote refrigerant supply. Double temperature control is used to prevent icing of the glass chamber. For this, the glass chamber is placed in a freon thermostatically controlled air cooler with a temperature of minus 5 to minus 10 ° C. The cell with the oil is cooled to a dewaxing temperature of minus 15 ° C. Inside the glass chamber, the required temperature is maintained with an accuracy of ± 1 ° C, which is recorded by the thermometer that the glass chamber is equipped with. The bronze cell is connected to the BC-20-10 rectifier. The additive reports the electrokinetic potential to the crystals of paraffin hydrocarbons formed at the dewaxing temperature. At an electric field strength of 7000-11000 V / cm, the oil is separated into paraffin hydrocarbons, which form a dense deposit on the electrodes, and transparent low-setting hydrocarbons (dewaxed diesel fuel) in the interelectrode space.

The effectiveness of the dewaxing process of oil products is estimated by the yield of the dewaxed product (dewaxed diesel fuel), by lowering the pour point of the dewaxed diesel fuel (pour point depression) relative to the pour point of the initial product without additives and by lowering the cloud point of the dewaxed diesel fuel (cloud point depression) relative to the cloud point source oil without additives.

Example 1. 8.18 g (0.0288 mol) of stearic acid, 1.82 g (0.0126 mol) of polyethylene polyamines, 10 g of diethylbenzene and 0.05 g of zinc oxide (0.5 wt.% Per charge of starting reagents) loaded into the reactor and boiled for 1 h until the reaction water is completely distilled off into a Dean-Stark trap filled with diethylbenzene. Then, diethylbenzene was distilled off under vacuum, and the remaining reaction water was distilled off for an additional 5 hours at a temperature of 235 ° C. The mass ratio of the starting reagents SK: PEPA is respectively 4.5: 1.0. The final acid number of the obtained amides SK 14 mg KOH / g Obtain 10 g of a polyamide additive.

To obtain a depressant additive used technical stearic acid (stearin) brand T 18 with the following properties: molecular weight 284; pour point 64.2 ° C; acid number 192.7 mg KOH / g; saponification number 195.1 mg KOH / g; iodine number 11.9 g of iodine / 100 g; mass fraction of unsaponifiable substances 0.48%. Stearic acid corresponded to GOST 6484-96. Polyethylene polyamines had the following properties: molecular weight 144; mass fraction of total nitrogen 31%; mass fraction of tertiary amino groups 6.6%; mass fraction of bottom residue boiling above 200 ° C, 69.6%; mass fraction of the fraction distilled off at a residual pressure of 1.3 kPa in the temperature range: a) up to 75 ° C - traces; b) from 75 to 200 ° C - 28.9%. Polyethylene polyamines meet the requirements of TU 2413-357-00203447-99. For the synthesis of amides of stearic acid and PEPA in the first stage, technical diethylbenzene was used as an azeotropic solvent, which is a mixture of isomers with a total content of at least 99.8 wt.%. The content of the para-isomer is about 30 wt.%, The ortho-isomer is not more than 3.8 wt.%, The rest is meta-diethylbenzene. Diethylbenzene corresponded to TU 2414-040-00203772-96. Zinc oxide is of reactive purity with physicochemical properties similar to published data.

Example 2. For electrodewaxing use summer diesel fuel with the following properties: pour point minus 5 ° C, cloud point minus 5 ° C; density at 20 ° C 839 kg / m ³ ; viscosity at 20 ° C 5 mm ² / s; 50% of diesel fuel boils at 277 ° C; aniline point 67.5 ° C; the hydrocarbon content of the complex with urea, 6.6 wt.%; the content of n-alkanes is C _12-15 45.91 wt.%, C _16-21 48.33 and C ₂₂₊ 5.76 wt.%.

Electrodewaxing of diesel fuel is carried out in a constant electric field in the presence of a condensation product of stearic acid and polyethylene polyamines in accordance with example 1. The content of the depressant additive by the present method is 0.05; 0.1 and 0.15 wt.%. Other dewaxing parameters are as follows: dewaxing temperature minus 15 ° C; the average electric field strength in the interelectrode space of the cell is 7000, 9000 and 11000 V / cm; cooling time of the initial diesel fuel with an additive of 60 min; electric processing time (deposition) 60 min. For the initial and dewaxed diesel fuel, pour points and cloud points are determined.

The results of dewaxing according to the method according to the invention are presented in the table. For comparison, the table also shows the results of dewaxing in accordance with the prototype, i.e. in the presence of a condensation product of synthetic fatty acids of fraction C _21-25 and polyethylene polyamines in a weight ratio of 5.5: 1.0, respectively (Pat. RF 2106390, 6 C10G 73/30. Publ. March 10, 1998 Bull. No. 7). Other process parameters of the prototype (content of the additive, dewaxing temperature, electric field strength and processing time in the electric field) were adopted the same as in the claimed method.

A comparison of the data on the dewaxing of diesel fuel according to the claimed method and the prototype (see table) shows that the use of the condensation product of stearic acid and polyethylene polyamines instead of the condensation product of the FFA fraction _21-25 and polyethylene polyamines gives a positive effect. For example, with average parameters, when the content of the additive is 0.1 wt.%, And the electric field is 9000 V / cm, the output of dewaxed diesel fuel increases from 74.1 to 84.6 wt.%. At the same time, the quality indicators of dewaxed diesel fuel - solidification temperature and cloud point are maintained at the same level. Obviously, the positive effect of the use of a depressant additive is determined by the higher depressant ability of the proposed additive and the stable electrokinetic potential of dispersed paraffin particles in the presence of this additive. The proposed additive, in contrast to the additive of the prototype, gives paraffin crystals a stable positive charge regardless of its content and electric field strength.

Claims (1)

The method of dewaxing oil products by mixing raw materials with a surfactant, heat treatment of the resulting mixture, cooling it to a dewaxing temperature followed by the release of paraffin hydrocarbons in a constant electric field, characterized in that the product of the interaction of stearic acid and polyethylene polyamines in mass the ratio, respectively, 4.5: 1.0.