Earth boring – well treating – and oil field chemistry – Preventing contaminant deposits in petroleum oil conduits
Reexamination Certificate
1994-09-01
2002-02-05
Dawson, Robert (Department: 1712)
Earth boring, well treating, and oil field chemistry
Preventing contaminant deposits in petroleum oil conduits
C507S128000
Reexamination Certificate
active
06344431
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a proposal for an improved handling of fluid hydrocarbon mixtures having a tendency forming solid organic deposits, especially based on hydrocarbons, upon storage and/or when processed, which deposits then will remain as undesired incrustations in the interior of pipelines, pumps, filters, containers and the like and require a considerable expenditure for cleaning. Particularly concerned by this problem are the areas of extracting, storing and/or conveying crude oils having high contents of paraffinic hydrocarbons and/or of correspondingly handling oil fractions containing such hydrocarbon compounds. Nevertheless, comparable problems may also arise in extracting and processing natural gas; hereto cf., for example, F. Kerekes et al., “Ma&bgr;nahmen gegen Paraffin-Ablagerungen in der Erdöl- und Erdgasförderung”, Erdöl-Erdgas-Zeitschrift 99 (4/1983), 110-118 and the literature quoted therein.
Functional disorders caused by a deposition of proportions of organic solids—and more particularly paraffins and/or asphaltenes—contained in hydrocarbon mixtures that are fluid under normal conditions are various in nature and, thus, become manifest in a great variety of ways. One important parameter in this respect is the temperature range of the pour point or of the setting point of the liquid hydrocarbon mixture. In the temperature range exceeding this value, the fluidity would be basically ensured, while the hydrocarbon mixture will solidify at temperatures below said value. Crude oils and/or hydrocarbon fractions having comparably high pour and setting points may be improved with respect to the flow property thereof also at reduced temperatures by the addition of so-called Pour Point Depressants (PPD's). The addition of PPD's, due to an interaction with the amounts of solids crystallizing in the liquid phase, reduces the limiting temperature below which the fluidity of the hydrocarbon mixture is lost.
However, independently of the problem area referred to herein, there exists a complex second problem area for the practical handling of such liquid hydrocarbon mixtures, but also of gaseous hydrocarbon mixtures. This is related to the incrustations which in practice give rise to a variety of disorders and have been formed by solid hydrocarbon compounds on the inner walls of, for example, pipelines, pumps, on filters or in storage tanks, which incrustations occur even if the fluidity of the hydrocarbon mixture itself is retained. Thus, for example, the interior of pipelines for the transportation of crude oil must be regularly subjected to cleaning procedures which are expensive in time and costs, because in the regular operation of conveying oil incrustations of solid hydrocarbon compounds are increasingly formed on the inner wall of the pipelines. The working order of pumps and filters is threatened by such formation of incrustations during the continuous operation, if incrustations of this type are uninhibitedly permitted to build up. Particular threats in thus directions are caused also by that the normally flowing liquid hydrocarbon-based material is intermittently exposed to inevitable standstill periods.
2. Discussion of Related Art
Hitherto the efforts made in the art for finding solutions to these problems have had only a restricted practical success. What has been desired is, by adding efficient inhibitors to prevent, or at least to reduce, this undesirable tendency towards incrustation and more particularly the strong adhesion of the, e.g., paraffinic incrustations to the solid surfaces being in contact with the liquid and/or gas phases. Here, the addition of the known PPD's lowering the setting and/or pour point(s) of the kind discussed above does not provide remedy. Really useful inhibitors for the goal according to the invention so far have not been proposed in connection with liquid hydrocarbon mixtures. The literature reference quoted above from Erdöl-Erdgas-Zeitschrift 99 deals with paraffin deposits from natural gas condensates, among others. Here, laboratory experiments were reported for developing paraffin inhibitors based on wetting agents and/or dispersants. Such wetting agents acting through a water phase form a surface film on the walls which largely counteracts a deposition of paraffins and/or infiltrates and mobilizes films already present, respectively. More specifically, for practical use there is proposed a combination of a nonylphenol ethoxylate and a dodecylbenzyl sulfonate.
The teaching according to the invention is based on the recognition that two substance classes preferably having a surfactant character as described in detail hereinbelow are capable of providing remedy to the problems concerned here in a hitherto unknown manner. These auxiliary agents of the invention, hereinbelow designated as the active substances (A) and (B), are obviously distinguished by that they are capable of striking and spreading on the solid work material surfaces—conventionally metal surfaces—and here counteract the attachment and growth of solid hydrocarbon deposits and, hence, the undesirable incrustation, supposedly so due to the chemical nature thereof.
DESCRIPTION OF THE INVENTION
Thus, the invention relates to the use of
(A) esters of phosphoric acid and/or partial salts thereof with alkoxylated aliphatic, cycloaliphatic and/or aromatic alcohols and/or
(B) fatty acid oligo-dialkanolamides
as inhibitors against the formation of solid hydrocarbon incrustations from hydrocarbon mixtures which are fluid and prone to form such incrustations. The term “aromatic alcohols” as used in the context of the component (A) includes phenols and corresponding compounds having the OH group(s) bonding to the aromatic moiety.
It is preferred to employ inhibitors according,to (A) and/or (B) which exhibit surfactant character and, in addition, are capable of-wet,tig solid work material surfaces and especially of spreading on solid work material surfaces also in the presence of the fluid hydrocarbon phase, even if this is comprised by liquid hydrocarbon mixtures. The inhibitors of the invention according to (A) and/or (B) are especially suitable for the protection of metallic work material surfaces which are in contact with the fluid hydrocarbon phase tending to form incrustations.
Re the definition of the inhibitors (A) according to the invention:
The active substances of this class of inhibitors used according to the invention are esters of phosphoric acid with selected alcohols. Included in the invention is the use of the phosphoric acid triesters. In preferred embodiments there are employed partial esters or mixtures of partial esters of phosphoric acid and the selected alcohols still to be described herein-below. In the case that such partial esters are used, it may be expedient to utilize the non-esterified acid groups in the form of salts thereof, and especially in the form of alkali metal salts, ammonium salts, alkanolamine salts and/or amine salts. As the inhibitor component (A) there may be particularly suitable mixtures of mono- and/or diesters of phosphoric acids and/or their respective salts.
Within the scope of this inhibitor component (A) there are employed, as the ester-forming alcohol components, alkoxylated aliphatic, cycloaliphatic and/or aromatic alcohols which preferably contain at least 3, especially at least 4 to 6, carbon atoms in the aliphatic, cycloaliphatic and/or aromatic alcohol moiety. A particularly suitable class of ester-forming alcohols is constituted by alkoxylated phenol- derivatives, among which alkoxylated alkylphenols may be of particular importance as phosphoric acid ester-forming alcohol components. Alkoxylated fatty alcohols constitute a further preferred class of compounds for composing the inhibitors (A).
As the alkoxylated products of said alcohols within the scope of the invention there are especially utilized the ethoxylated and/or propoxylated derivatives of monofunctional alcohols or phenols, respectively. The degree of alkoxylation may be, for example
Groffe Jacques
Herold Claus-Peter
Rouet Jean
von Tapavicza Stephan
Zoellner Wolfgang
LandOfFree
Use of selected inhibitors against the formation of solid... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Use of selected inhibitors against the formation of solid..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Use of selected inhibitors against the formation of solid... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2959252