Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
1999-08-04
2002-01-29
Lovering, Richard D. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C507S090000, C516S022000, C516S027000, C524S106000, C524S379000, C524S923000
Reexamination Certificate
active
06342553
ABSTRACT:
The present invention relates to dispersions of ester polymers, and for their preparation and use, particularly in petroleum industry pipelines.
Crude oils are complex mixtures comprising hydrocarbons of varying types and molecular weights. One class of hydrocarbon present in the oils is paraffins which are linear, branched chain or cyclic hydrocarbons having at least 18 carbons which can form waxy solids. The solubility of these waxy solid forming components in the crude oils is predominantly temperature-dependant. They are usually soluble in the crude oil under down-hole conditions i.e. high pressures or high temperatures. However as the oil is brought to the surface its temperature and pressure are reduced. As a result the wax may begin to precipitate out and may form deposits on any cooler surface with which it comes into contact. These wax deposits can cause problems, such as blockage of pipelines, valves and other process equipment. The wax may also deposit in pipelines subsequently used to transport crude oil or fractions derived from the total product brought up from down-hole, such as fractions comprising gas, e.g. natural gas, and/or water, as well as a liquid hydrocarbon body, e.g. crude (or black) oil or “condensate”; the pipelines may thus be hydrocarbon lines or multi phase transportation lines with oil, gas and/or water. The wax may deposit on surfaces of metal e.g. of ferrous metal.
The contents of the transport pipelines are often cooler than the contents of lines on oil platforms or in refineries. This cooling is especially critical in respect of lines from offshore oil fields to the land and land lines in cold territories such as Alaska.
Wax deposition may be reduced in a number of ways, including keeping the lines hot, diluting the oil with solvent, or using special additives which interfere with wax crystal growth.
The special additives may usually be added to the pipeline upstream of the location of any potential cold area likely to result otherwise in deposition of wax. They may be added as a concentrate for ease of handling and are diluted by the oil to the requisite level for use. However some additives are difficult to form as concentrates for this purpose, because the concentrate is either too viscous or solid at the concentration required, especially at low temperatures, such as 10°, 5° or −1° C., conditions that may be experienced by the concentrate during its travel to the pipeline e.g. from an offshore platform.
We have discovered how to make concentrates of such additives.
The present invention provides a dispersion of an ester polymer in at least one first organic liquid, said ester polymer having a hydrocarbon backbone and at least a first type of side chain which is a long chain aliphatic group of at least 14 carbon atoms and especially also at least a second type of side chain, which is an alkyl of 1-13 carbons, said polymer being present in said dispersion in at least 10% e.g. at least 20% by weight.
The present invention also provides a dispersion of said ester polymer in an aqueous medium, said polymer being present in said dispersion in at least 10% e.g. at least 20% by weight.
The ester polymer usually has a backbone consisting essentially of carbon atoms in hydrocarbon groups to which backbone at least one side chain is attached via an ester group linkage. Usually each of the first and second types of side chain is linked to the backbone via an ester group linkage.
The ester polymer may be a polymer of a monomer with structural units derived from at least one ester (1) of an aliphatic carboxylic acid with an aliphatic alcohol, wherein one of the acid and alcohol is ethylenically unsaturated and the other of the acid and alcohol has a long chaingroup e.g. of 14-40 carbons, and optionally at least one of a monomer, which is a monomer with structural units derived from a different ester (2) within the same definition as ester 1, such that the mole average carbon content of the long chain group is 15-35 preferably 16.5-24 especially 17.5-22 or that at least 50% of the long chain groups have 15-35 carbons preferably 16.5-24 especially 18-22 carbons. In particular the ester polymer also is of at least one monomer with structural units derived from a corresponding ester (3) with structural units derived from an aliphatic carboxylic acid and an aliphatic alcohol, wherein one of the acid and alcohol is ethylenically unsaturated and the other has an aliphatic group e.g. of 1-13 carbons, such that at least 30% e.g. at least 50% of the said aliphatic groups have 15-35 carbons preferably 16.5-24 especially 18-22 carbons. Preferably the ester polymer comprises structural units from esters (1) and (3), and optionally (2).
The present invention also provides a dispersion of at least two different polymers selected from homopolymers (A) with structural units derived from an ester (1) and copolymers (B) thereof with structural units derived from a different ester (2) within the same definition as ester 1, such that the mole average carbon content of the long chain group is 15-35 preferably 16.5-24 especially 17.5-22 or that at least 30% e.g. at least 50% of the long chain groups have 15-35 carbons preferably 16.5-24 especially 18-22 carbons, and copolymers (C) of said ester (1) and optionally ester (2) with a corresponding ester (3) such that at least 30% e.g. at least 50% of the said aliphatic groups have 15-35 carbons preferably 16.5-24 especially 18-22 carbons.
The dispersion may also comprise
a) component (I), which is at least one N-substituted polyalkyleneimine compound with chain nitrogen atoms, which has at least one organic substituent of at least 6 carbon atoms on at least one nitrogen atom and/or
b) component (II) selected from at least one polymer of said homopolymers (A), copolymers (B) and copolymers (C) with the proviso that the dispersion comprises at least 2 components of which at least one is a component (I).
The dispersion of the invention may comprise at least two components (I) or may comprise at least one component (I) together with at least one component (II), which is preferably copolymer (C) and at least one of polymer (A) and (C).
The present invention also provides a dispersion of a polymer in at least one liquid, the polymer comprising at least one polymer A, B or C or component I, together with at least one monomeric additive, which has an aliphatic group of at least 14 carbons and a polar group, preferably a group containing one or more nitrogen atoms, especially with at least one tertiary or secondary amino nitrogen (and optionally in addition a primary) amino nitrogen atom, in particular in a heterocyclic group containing at least I nitrogen atom.
Preferably these polymers are obtainable by or obtained by transesterification of at least one polymer of an ester (3) with an aliphatic alcohol or carboxylic acid having an aliphatic group of 14-40 or 15-35 e.g. 16-24 carbons (depending on whether the acid or alcohol in ester 1 is unsaturated or aliphatic); the conversion may be substantially complete, but preferably is only 30-97% such as 30-90% e.g. 40-90% or 50-90%.
Ester 1 may be derived from an ethylenically unsaturated carboxylic acid and a long chain alcohol and in this case ester 2 and/or, ester 3 (if present) are of this same type; alternatively ester 1 may be derived from an ethylenically unsaturated alcohol e.g. “vinyl alcohol” and a long chain aliphatic carboxylic acid, and in this case ester 2 and/or ester 3 if present are of this same type.
The transesterification product may be used as such i.e. containing any unreacted polymer of ester (3) and/or unreacted alcohol or acid (respectively) with a 14-40 e.g. 16-24 carbons group, e.g. in amount of 1-50% e.g. 10-50% (by weight, based on the weight of polymer (3)) especially for unreacted alcohol. The unreacted alcohol or acid respectively may be substantially removed so the product may be in the substantial absence of said alcohol or acid.
The present invention also provides a method of reducing wax formation and/or deposition in wax-containing oil preferably i
Hodgson Philip Kenneth Gordon
Taylor Spencer Edwin
BP Chemicals Limited
Lovering Richard D.
Nixon & Vanderhye
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