Petroleum bioprocessing to prevent refinery corrosion (Her Majesty The Queen In Right Of Canada As Represented By The Minister Of Natural Resources Canada)

PATENT
Petroleum bioprocessing to prevent refinery corrosion (Her Majesty The Queen In Right Of Canada As Represented By The Minister Of Natural Resources Canada)
Publication number
EP2419493 A1
Application number
EP20090843182
Publication date
Feb 22, 2012
Also published as
CA2755630A1, US20120028341, WO2010118498A1
Inventors
Louis D. Heerze
Applicant
Her Majesty The Queen In Right Of Canada As Represented By The Minister Of Natural Resources Canada
EP 2419493 A1 (text from WO2010118498A1)
Abstract
The present invention relates to the bioupgrading of crude oil is directed to a process for decreasing the acidity of an acidic crude oil, comprising contacting an acidic crude oil with a mixture nitrogen containing compounds selected from the group comprising ammonia, ammonia hydroxide, amines and the salts thereof, and in the presence of lipase enzyme, under conditions of suitable temperature and pressure sufficient to form the corresponding amide. The resulting naphthenic acid derived amides can then be processed normally in a refinery using such processes as cracking or hydrotreating and converted to hydrocarbon, ammonia and carbon dioxide without causing damage to the refinery infrastructure. This enzyme process is done at reduced temperatures (40-60°C) and pressures requiring less energy.
Description
Field of the Invention The present invention relates to a process for bioupgrading crude oil. More specifically, the present invention discloses the use of lipase enzyme to convert naphthenic acid compounds, in combination with ammonia hydroxide or other amines, into amides that do not possess any corrosive properties. The resulting naphthenic acid derived amides can then be processed normally in a refinery using such processes as cracking or hydrotreating and converted to hydrocarbon, ammonia and carbon dioxide without causing damage to the refinery infrastructure.
Background of the Invention
The quality of crude oil throughout the world is reduced by acidic components found in the oil. During refining, at temperatures between 220 and 400 0C, these species can become corrosive. Acidic species such as naphthenic acids that have boiling points in this temperature range will condense on metal surfaces leading to damage in the refinery infrastructure, potential safety issues, and costly repairs. As a result, oils with high acid content, whether from conventional (crude oil) or oil sands (bitumen) sources, are more difficult to market and their value is significantly discounted.
Conventional methods to remove corrosive species from crude oil involve costly and energy-intensive chemical and thermal processes. For example, the current technologies developed to remove organic acids from crude oil involve either thermal decomposition at 400°C (Blum et al. in U.S. Patent 5,820,750), adsorbing onto inert materials (Varadaraj in U.S. Patent 6,454,936), treating with surfactants (Gorbaty et al. in Canadian Patent 2,226,750) or converting the organic acids into various derivatives that are easier to remove (Brons in U.S. Patent 5,871,637, Sartori et al. in Canadian
Patents 2,343,769 and 2,345,271, and Varadaraj et al. in U.S. Patent 6, 096,196). Efforts to minimize organic acid corrosion have included a number of approaches for neutralizing and removing the acids from the oil. For example, there are numerous approaches in the literature on the reduction of the organic acid species in crude oil. They include thermal decomposition of organic acids using high temperatures in the presence (U.S. Patents 5,914,030, 5,928,502) or absence (U.S. Patent 5,820,750) of a metal catalyst and treatment of corrosive acids with group IA and HA metal oxides, hydroxides and hydrates to form metal salts of naphthenic acids which are then thermally decomposed at elevated temperatures (U.S. Patents 5,985,137, 5,891,325, 5,871,637, 6,022,494, 6,190,541, 6,679,987). Other methods include chemical formation of esters of the organic acids in the presence of alcohol and a base (U.S. Patents 5,948,238, 6,251,305, 6,767,452, and Canadian Patent 2,343,769), reducing acidity by the formation of various salts of organic acids using base (U.S. Patents 5,643,439, 5,683,626, 5,961,821, 6,030,523), removal of naphthenic acids using detergents or surfactants (U.S. Patents 6,054,042, 6,454,936), absorbing organic acids onto polymeric amines (U.S. Patents 6,121,411, 6,281,328) and by adding corrosion inhibitors to crude oil to prevent naphthenic acid induced metal corrosion (U.S. Patent 5,552,085).
U.S. Patent 6,258,258 and Canadian Patent 2,345,271 describe the formation of naphthenic acid amides by treating crude oil with excess ammonia at elevated temperatures (above 180 0C) and elevated pressures (100-400 kPa).
While these processes have achieved varying degrees of success, most of these methods are costly and energy-intensive and their effectiveness somewhat limited. As a result, there is a need to develop alternative approaches to eliminate the corrosive species in petroleum and for treating acidic crudes.
Recently it has been reported that lipase B (Mickiyo in European Patent 0287634), from the fungi Candida Antarctica, produced by industrial enzyme producer Novozymes, demonstrated catalytic activity in the hydrolysis of fatty acids and converts them into fatty acid esters in the presence of alcohol (Anderson et al. in Biocat. Biotrans. 1998, 16, 181-204). The enzyme also has the ability to convert fatty acids, carboxylic acids and triglycerides into amides by the addition of amines or ammonia (DeZoete et al. in PCT Patent Application PCT/EP 1994/003038 with publication number WO 95/07359; DeZoete et al. in Ann. NY Acad. ScL 1996, 799, 346-350; Egraz in U.S. Patent 5,973,203; Hacking et al. in Biotech. Bioeng. 2002, 68, 84-91; Ignacio et al. in Chem. Soc. Rev. 2004, 33, 201-9; Irimescu et al. in Tet. Lett. 2004, 45, 523-525; Litjens et al. in PCT WO 00/58490; Madeira Lau et al. in Org. Lett. 2000, 2, 4189-4191; and Tuccio et al. in Tet. Lett. 1991, 32, 2763-2764).
However, the art is substantially bereft of methods for upgrading the quality of crude oil comprising naphthenic acids by the use of enzymes or biocatalysts. U.S. Patents 7,101,410, 6,461,859 and 5,358,870 describe the use of biocatalysts, such as bacteria, fungi, yeast, and algae, hemoprotein, and a cell-free enzyme preparation from Rhodococcus sp. ATCC 53969, respectively, to improve the quality of oil specifically target organic sulphur containing molecule by reducing the sulphur content as well as lowering their viscosity. U.S. Patent 5,858,766 describes the use of microorganisms (a bacteria strain) in a bioupgrading capacity to selectively remove organic nitrogen and sulphur in oil as well as remove metals.
There remains the need for bioprocesses, as an attractive alternative to current upgrading methods, that use enzymes to improve the quality of crude oil and bitumen by removing acidic species.
Summary of the Invention
The present invention is directed to bioupgrading, i.e., using enzymes to improve the quality of crude oil and bitumen. The advantages of bioupgrading technologies lie in that they operate under much milder conditions, for example, at lower temperatures and pressures, compared to those required by conventional technologies. Consequently, much less energy will be required. As a result, the environmental impacts would be reduced. Furthermore, since biocatalysts and enzymes are specific in their conversions, only the undesirable components - in this case, corrosive species - are converted into non-corrosive ones without affecting the rest of the crude oil. The result is an improvement in the overall quality of the oil and refinery corrosion prevention.
The present invention identifies a bioupgrading use for a lipase enzyme, more specifically but not limited to lipase B (Novozyme™ 435) originally isolated from the fungi Candida antarctica, and now a recombinant enzyme expressed in Aspergillus oryzae. This lipase enzyme has the capability to convert organic acids including naphthenic acid model compounds, in combination with ammonia hydroxide or other amines, into chemical species (amides) that do not possess any corrosive properties. The amide products generated from enzyme reaction were confirmed by gas chromatography-mass spectrometry (GC-MS) analysis. The resulting naphthenic acid derived amides can then be processed normally in a refinery using such processes as cracking or hydrotreating and converted to hydrocarbon, ammonia and carbon dioxide without causing damage to the refinery infrastructure.
One of the advantages of this lipase B enzyme is that the enzyme is thermostable and can function at temperatures of 40-60°C. The enzyme can carry out bioconversions in organic solvents such as toluene or heptane and possesses broad substrate specificity. As such, lipase B, and/or similar suitable enzymes, can be used to reduce the corrosive properties of crude oil and bitumen by converting organic acids including naphthenic acids in crude oil into a non-corrosive species such as naphthenic acid amides. This process is done at reduced temperatures (40-60°C) and pressures that require less energy. The resulting naphthenic acid derived amides can then be processed normally in a refinery using such processes as cracking or hydrotreating and converted to hydrocarbon, ammonia and carbon dioxide without causing damage to the refinery infrastructure.
In one aspect of the present invention, it discloses a process for decreasing the acidity of an acidic crude oil, comprising: a. contacting an acidic crude oil with at least one nitrogen containing compound, and b. incubating the mixture obtained from step (a) in the presence of lipase enzyme; under conditions of suitable temperature and pressure sufficient to form the corresponding amides.
Free Full Text Source: http://www.google.com/patents/EP2419493A1?cl=en