DE2037673C2 - Polymer mixtures as pour point improvers for hydrocarbons and their use - Google Patents

Description

consists, each of the copolymers containing 99 to 40 percent by weight Äthylencinhcilen and the The weight ratio of the two copolymers is in the range from 20: 1 to 1:20

2. Use of the pour point improver according to claim 1 in conventional petroleum distillate fuels a boiling range from 100 ° to 450 ° C in amounts of 0.005 to 0.5 percent by weight, based on the Weight of the distillate fuel.

The invention relates to the subject matter characterized in the claims.

Certain polymers are already available as pour point improvers for petroleum distillers and fuels known, as described for example in GB-PS 9 00 202.9 13 715.9 22 748 and 10 03 314. Other polymers have been developed for use with residual fuels and crude oils, such as them for example in GB-PS 11 47 904 are listed. From US-PS 30 37 850 a polymer mixture is also known as a pour point improver, which is composed of an alkylated polystyrene and a copolymer of There is also ethylene and vinyl acetate. US Pat. No. 3,389,979 describes the use of copolymers from ethylene and vinyl acetate as pour point improvers.

It is now out of the Praxb known that it is sometimes difficult the fluidity of hydrocarbons and in particular the fluidity of petroleum distillate fuels or -brennstoffen to improve with a boiling range of 100 ° to 450 ⁰ C, because the known pour point depressants not always a allow sufficient effect.

The aim of the invention was therefore to find improved polymer mixtures as pour point improvers for hydrocarbons to create.

This object has now been achieved in that, according to the invention, to improve the pour point of Hydrocarbons, a polymer mixture is proposed which consists of

(A) an ethylene-vinyl acetate copolymer with a molecular weight (number average) of 700 to 3000 and

(b) an ethylene-vinyl acetate copolymer with a molecular weight (number average) of over 300½ up to 60,000

consists, each of the copolymers containing 99 to 40 percent by weight of ethylene units and the Weight ratio of the two copolymers in the range from 20: 1 to 1:20!

It was highly surprising that the polymer mixture according to this invention had the pour point of hydrocarbons improved to an extent that is beyond the expected additive effect of the individual Copolymers goes far beyond, so a synergistic effect is achieved.

Desirably, the number average molecular weight of the copolymer (a) is in the range of 1500 to 2500 and the molecular weight (number average) of the copolymer (b) in the range from 4000 to 20,000, for example from 5,000 to 15,000.

. It is preferred in the polymer blends of this invention that each of the interpolymers be preferred Contains 90 to 50 Geichtspro / cnt ethylene and the weight ratio of the two copolymers preferably in the range from 3: 1 to 1: 3)

Although the separate copolymer components can be mixed as such, it generally is desirable to make a concentrate. This can be done by each one with a separate solvents, but most conveniently that one each in a conventional Solvent dissolves. It can therefore use the mixed polymer (a) with the low molecular weight in kerosene or cyclohexane and the copolymer (b) in a kerosene extract or slack (a wax that is without Purification or refining obtained from a lubricating oil dewaxing process). as The usual solvent for both copolymers is the use of an aromatic solvent.

for example by test subjects, preferred. Suitable concentrates can be used as active ingredients 5 to 95% of the copolymer (a) and 95 to 5% of the copolymer (b) (based on the total weight of the existing copolymer) included.

The copolymers (a) with the lower molecular weight can be prepared by customary processes using free radical catalysts, preferably organic peroxide compounds. Suitable methods are described in some of the UK patents mentioned above. It is expedient to use polymerization temperatures of 100 ° to 130 ° C. and pressures of 34.5 to 38.9 bar.
The copolymers (b) with the higher molecular weight can according to the in GB-PS 11 47 904 §§

described method are produced.

The "number center!" Of the molecular weight is to be understood as the molecular weight that means Vapor phase osmometry (using a »Mechrolab Vapor Phase Osmometer 301A«) or by means of Membrane osmometry (using a »Mechrolab Membrane Osmometer 501«) is measured.

According to this invention, the polymer blend is according to claim 1, used in conventional petroleum distillate fuels with a boiling range of 100 ° to 450 ⁰ C in quantities of 0.005 to 0.5 weight percent, based on the weight of distillate fuel

The amount of polymer mixture used is preferably from 0.005 to 0.1 / 0.2 percent by weight, based on the weight of the distillate fuel.

The polymer mixture according to the invention can of course be customary in addition to a large number of others Additives that may be present in petroleum distillate fuels can be used. Such additives are for example rust inhibitors, demulsifiers, corrosion inhibitors, antioxidants, dispersants. Dyes, color stabilizers, haze inhibitors, antistatic agents, other pour point improvers or pour point depressants.

example

An ethylene-vinyl acetate copolymer with a low molecular weight was obtained by converting ethylene and vinyl acetate prepared in an autoclave. The catalyst used was Lauroylperoxsd that The temperature was maintained at about 105 ° C and the pressure at about 72.4 bar. Cyclohexane was used as the solvent The product used had a number average molecular weight of about 2100 (according to vapor phase osmomelry) and a vinyl acetate content of 38 percent by weight. This copolymer was used as a copolymer A denotes

A high molecular weight ethylene-vinyl acetate copolymer was produced by a reaction as described in Example 3J of GB-PS 11 47 904. The product had a molecular weight (Number average) according to vapor phase osmometry) of 10,000 and a vinyl acetate content of 26 percent by weight This copolymer was referred to as copolymer B.

Two fuels (heating oils) were used. Fuel 1 was a petroleum distillate from an Oman crude oil with a boiling range of 193 ° to 353 ° C. He had a specific gravity of 15/4 ° C of 0.8319, a kinematic viscosity at 37.8 ° C of 2.93 · 10 ^-2 cm ² / s, an aniline point of 71.9 ° C and a sulfur content of 0.68 percent by weight

Fuel 2 ws_ a petroleum distillate from a mixture of Kirkuk and Arzew crude oils with a boiling range of 167 ° to 364 ° C. It had a specific gravity of 60/6 ⁰ C of 0.8247, a kinematic viscosity of 37, 8 ⁰ C of 2.46 · 10 ^-2 cm ² / s, an aniline point of 70.6 ⁰ C and a sulfur content of 0.23 weight percent.

These two fuels have undergone a study for their low temperature utility subject. This investigation, which is particularly intended for diesel fuels, is called "Cold Filter Plug Point «(CFPP) test. The procedure is detailed in journal inst. Pet. Vol. 52, No. 510, pp 173 to 185, in particular on pages 184 and 185, described.

^{The CFPP value was measured in (0} C) for each of the two fuels, (1) ksin AcUniv, (2) each copolymer being used separately and (3) the two copolymers being used together.

The results are summarized in Table 1 below.

It should be noted that the copolymer Λ was used as a preparation, the 50 percent by weight Active ingredient contained in kerosene. The copolymer B was used as preparation, the 25 percent by weight Active ingredient contained in kerosene extract. The weights in column 2 of table 1 therefore relate on the weights of the preparations used

Table I.

fuel Encore preparation preparation Preparation from preparation (Wt .-%) Copolymer A Mixed polymer B Copolymer A and CFPP ( ⁰ C) CFPP ( ⁰ C) Preparation Mixed polymer B (Weight ratio 1: 1) CFPP ( ⁰ C) No -6 -6 -6 1 0.01 -8th -10 -12 0.03 -8th -11 -13 0.0b -8th -13 -19 No -b -6 -6 2 0.01 -6 -10 -15 0.03 - 7th -11 -17 0.06 -7 -12 -21

The results clearly show the synergistic results obtained using the two additives.

In further comparative tests subsequently submitted on June 20, 1978, the polymer mixture according to the invention was used from the copolymers A and B given above in a weight ratio of 1: 1 den Contrasted combinations that are known from US Pat. No. 3,389,979 and 3,037,850.

20th 25th 30th 35 40 45 50

65

The comparative tests were carried out using two different fuels, viz

of fuel A, which has a distillation range of 180 ° to 365 ° C and an aromatic content of 30% by volume, and
of fuel B, with a distillation range of 185 to 376 ° C and an aromatic content of 22 vol%.

The above-mentioned CFPP test was used to determine the effect of the pour point improvers examined used. The results obtained are summarized in Tables II and III below

Tabeile ιϊ

CFPP test on fuel A.

Additive content of the According to the invention Additive according to Additive according to Fuel Polymer mixture U.S. Patent 33 89 979 U.S. Patent 30,37,850 (Wt .-%) CFPP temperature CFPP temperature CFPP temperature CO ro ro

0 -4.5 -4.5 -4.5

0.005-9-4.5-4

0.01 -12 -7.5 -5.5

0.015 -13.5 -9.5 -8

0.02 -14.5 -10 -10.5

0.025 -15 -12.5 -13

Table III

CFPP test on fuel B

Additive content of the inventive additive according to additive according to

Fuel polymer mixture US-PS 33 89 979 LIS-PS 30 37 850

(Wt%) CFPP temperature CFPP temperature CFPP temperature

CO CO ("C)

0 -4.5-4.5 -4.5

0.005 -10.5 -3.5 -5

0.01 -14 -6 -7.5

0.015 -15.5 -7 -Π

0.02 -16 -10.5 -15

0.025 -17 -12 -17

From the above Tables II and IH it can be readily seen that the polymer mixture according to the invention represents a much better pour point improver than the previously known materials, what can be easily read off from the significantly lower CFPP temperature with the same active ingredient switches leaves. It can be seen that with a much smaller amount of the polymer mixture according to the invention *, succeeds in exerting the same effect on the flow behavior that when using the previously known Additive can only be achieved with significantly higher amounts of additive.

Finally, the following investigations (submitted on April 22, 1982) were carried out. For the A distillate fuel with the following properties was used in experiments:

Paraffin excretion begins - 6.0 ° C

Cloud point -3.0 ° C

CFPP (untreated) -5.0 "C

Boiling analysis according to ASTM D-86

Boiling point at the beginning 180 ° C

Boiling point after distilling off 20% 223 ⁰ C

Boiling point after distilling off 50% 268 ° C

Boiling point after distilling off 90% 336 "C

Boiling point at the end of the distillation 365 ° C

As components for the polymer mixture according to the present invention

(a) an Ethylcn-Vinylacelat-Mischpolymcrisal, namely the "mixed polymer A" and explained in more detail above (b) an Ethylcn-Vinyllacetat-Mischpolymcrisal, the 29 weight percent vinyl acetate-ninhcitcn cnlhicli, with a Molecular weight (number milliliters) of 6009 ("mixed polymers")

used.

These two copolymers according to (a) and (b) now became polymer mixtures according to the invention
made with different mixing ratios. These ratios are shown in Table IV below
in the middle column. These polymer mixtures were now in the first column of the table
The specified amounts are added to the distillate fuel described above and the CFPP value in ⁰ C is determined.

Table IV relationship CFPP value Addition to (Wt (P) ("C) Polymer mixture (ppm) -5 1: 5.4 -19 160 1: 1.8 -17 140 1.7: 1 -15 120 11.1: 1 -10 104

From the values given it can be seen clearly that the polymer mixture according to the invention is its
synergistic effect developed within a wide mixing ratio of the two mixed polymer components.

Claims (1)

Patent claims: 1. Polymer mixture from a pour point improver for hydrocarbons, characterized in that that it is off (A) an ethylene-vinyl acetate copolymer with a molecular weight (number average) from 700 to 3000 and (B) an ethylene-vinyl acetate copolymer with a molecular weight (number average) of over 3,000 to 60,000