WO2023218016A1

WO2023218016A1 - Biosourced hydrocarbon barrier fluids

Info

Publication number: WO2023218016A1
Application number: PCT/EP2023/062719
Authority: WO
Inventors: Dong Chen; Nicolas CHAMPAGNE
Original assignee: Totalenergies Onetech
Priority date: 2022-05-13
Filing date: 2023-05-12
Publication date: 2023-11-16
Also published as: FR3135462A1

Abstract

The invention relates to the use of a hydrocarbon fluid as a barrier fluid, said hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 500 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having a biodegradability at 28 days of at least 60% measured according to standard OCDE 301B and a flash point greater than or equal to 100°C according to standard ASTM D92.

Description

DESCRIPTION

TITLE: BIOSOURCE HYDROCARBON DAM FLUIDS

TECHNICAL FIELD OF THE INVENTION

The invention relates to the use of a biosourced isoparaffinic fluid as a barrier fluid, for example in seals used in rotating machines.

STATE OF THE ART

Rotating machines generally use rotating shafts and housing and a process fluid. The sealing of the rotating system is an important constraint of this type of machine, to ensure that there is no leak of the process fluid.

Seals used in rotating machines are also called mechanical seals. These are devices which ensure the dynamic sealing of a rotating system.

The rotating system can for example be a pump or a compressor using a fluid, called process fluid. Process fluids are traditionally of the base or concentrated acid type or of the petroleum distillate type (light hydrocarbons).

With pumping equipment operators becoming increasingly concerned about safety and the environmental impact that can result from a mechanical seal leak, dual mechanical seals are increasingly being used in the industry. A dual mechanical seal provides a second (outer) seal to contain the pumped fluid by creating a cavity or chamber between the inner and outer seals that can be filled with fluid. When this fluid is not under pressure, it forms a buffer between the pumped fluid and the atmosphere and is commonly called a buffer fluid. When pressurized, it forms a barrier between the pumped fluid and the atmosphere and is known as a barrier fluid.

Among the barrier fluids traditionally used, we can cite hydrocarbon fluids of fossil origin, such as polyalphaolefins, or even aqueous fluids comprising, for example, ethylene glycol or propylene glycol.

The present invention aims to provide a barrier fluid of biological origin and which is compatible with most process fluids which are used in the seals of rotating machines or double mechanical seals. SUMMARY OF THE INVENTION

The invention relates to the use of a hydrocarbon fluid as a barrier fluid, said hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 500 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having a 28-day biodegradability of at least 60% measured according to the OECD 301 B standard and a flash point greater than or equal to 100°C according to the ASTM D92 standard.

Preferably, the hydrocarbon fluid has a viscosity at 40°C ranging from 2 to 15 mm ² /s, preferably from 2.5 to 12 mm ² /s, preferably from 3 to 10 mm ² /s, more preferably from 3 at 7 mm ² /s, or even 3 to 5 mm ² /s.

Preferably, the hydrocarbon fluid comprises: at least 95% by weight of isoparaffins, preferably at least 96% by weight of isoparaffins, relative to the total weight of the hydrocarbon fluid; and/or less than 5% by weight of n-paraffins, preferably less than 4% by weight of n-paraffins, relative to the total weight of the hydrocarbon fluid; and/or less than 300 ppm by weight of aromatics, preferably less than 200 ppm by weight of aromatics, even more preferably less than 100 ppm by weight of aromatics, relative to the total weight of the hydrocarbon fluid; and/or less than 1% by weight of naphthenic compounds, preferably less than 0.5% by weight of naphthenic compounds, preferably less than 500 ppm by weight of naphthenic compounds, relative to the total weight of the hydrocarbon fluid.

According to one embodiment, the hydrocarbon fluid has a pour point less than or equal to -15°C, preferably less than or equal to -20°C, more preferably less than or equal to -30°C, even more preferably less than or equal to -40°C.

Preferably, the hydrocarbon fluid has a flash point greater than or equal to 120°C, preferably greater than or equal to 140°C, according to the ASTM D92 standard.

According to one embodiment, the hydrocarbon fluid is obtained by a process comprising at least one catalytic hydrogenation step at a temperature of 80 to 180°C and at a pressure of 50 to 160 bars of a deoxygenated charge of biological origin and isomerized.

According to one embodiment, the hydrocarbon fluid comprises at least 95% by weight of isoparaffins and less than 300 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having a biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 120°C according to the ASTM D92 standard, a viscosity at 40°C ranging from 3 to 10 mm ² /s, and a pour point less than or equal to -15°C. Preferably, the hydrocarbon fluid is used as a double mechanical seal barrier fluid, said fluid being under pressure.

The invention also relates to a double mechanical seal comprising a hydrocarbon fluid, said hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 500 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having a 28-day biodegradability of at least 60% measured according to the OECD 301 B standard and a flash point greater than or equal to 100°C according to the ASTM D92 standard, said hydrocarbon fluid being under pressure.

Preferably, the hydrocarbon fluid used in the mechanical seal of the invention has one or more of the following characteristics: the hydrocarbon fluid has a viscosity at 40°C ranging from 2 to 15 mm ² /s, preferably 2, 5 to 12 mm ² /s, preferably 3 to 10 mm ² /s, more preferably 3 to 7 mm ² /s, or even 3 to 5 mm ² /s; and/or the hydrocarbon fluid comprises: o at least 95% by weight of isoparaffins, preferably at least 96% by weight of isoparaffins, relative to the total weight of the hydrocarbon fluid; and/or o less than 5% by weight of n-paraffins, preferably less than 4% by weight of n-paraffins, relative to the total weight of the hydrocarbon fluid; and/or o less than 300 ppm by weight of aromatics, preferably less than 200 ppm by weight of aromatics, even more preferably less than 100 ppm by weight of aromatics, relative to the total weight of the hydrocarbon fluid; and/or o less than 1% by weight of naphthenic compounds, preferably less than 0.5% by weight of naphthenic compounds, preferably less than 500 ppm by weight of naphthenic compounds, relative to the total weight of the hydrocarbon fluid; and/or the hydrocarbon fluid has a pour point less than or equal to -15°C, preferably less than or equal to -20°C, more preferably less than or equal to -30°C, even more preferably less than or equal at -40°C; and/or the hydrocarbon fluid has a flash point greater than or equal to 120°C, preferably greater than or equal to 140°C, according to the ASTM D92 standard; and or the hydrocarbon fluid is obtained by a process comprising at least one catalytic hydrogenation step at a temperature of 80 to 180°C and at a pressure of 50 to 160 bars of a deoxygenated and isomerized charge of biological origin; and/or the hydrocarbon fluid comprises at least 95% by weight of isoparaffins and less than 300 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having a biodegradability at 28 days of at least 60% measured according to OECD 301 B, a flash point greater than or equal to 120°C according to ASTM D92, a viscosity at 40°C ranging from 3 to 10 mm ² /s, and a pour point less than or equal to - 15°C.

The invention makes it possible to provide a barrier fluid having high biodegradability and which is of biological origin.

The invention makes it possible in particular to provide a barrier fluid of biological origin, having high biodegradability, and having better resistance to oxidation than the barrier fluids currently used.

The invention makes it possible in particular to provide a biodegradable barrier fluid of biological origin whose viscosity is more stable over a wide temperature range. In other words, the viscosity of the hydrocarbon fluid used in the invention varies less with temperature than the viscosity of polyalphaolefin type barrier fluids.

The invention makes it possible to provide a barrier fluid having excellent compatibility with process fluids, also called process fluids, which makes it possible to avoid interactions/reactions with the process fluids themselves. in the event of a leak if the process fluid comes into contact with the barrier fluid.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to the use of a hydrocarbon fluid as a barrier fluid, said hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 500 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having a 28-day biodegradability of at least 60%, measured according to the OECD 301 B standard, and a flash point greater than or equal to 100°C according to the ASTM D92 standard.

As a preliminary note, it should be noted that, in the following description and claims, the expression “between” must be understood as including the limits cited.

Unless otherwise stated, percentages are expressed by weight.

For the purposes of the present invention, the word “paraffins” includes isoparaffins and n-paraffins. For the purposes of the present invention, the word “isoparaffins” designates non-cyclic branched alkanes.

For the purposes of the present invention, the word “n-paraffins” designates non-cyclic linear alkanes.

For the purposes of the present invention, the word “naphthenes” designates cyclic (non-aromatic) alkanes.

The hydrocarbon fluid used according to the invention comprises at least 90% by weight of isoparaffins, preferably at least 95% by weight of isoparaffins, preferably at least 96% by weight of isoparaffins, relative to the total weight of the hydrocarbon fluid.

The hydrocarbon fluid used according to the invention comprises less than 10% by weight of n-paraffins, preferably less than 5% by weight of n-paraffins, preferably less than 4% by weight of n-paraffins, relative to the total weight of the hydrocarbon fluid.

The hydrocarbon fluid used according to the invention comprises a content by weight of aromatic compounds less than 500 ppm by weight, preferably a content by weight of aromatic compounds less than or equal to 300 ppm, preferably less than or equal to 200 ppm, preferably less than or equal to 100 ppm, preferably less than or equal to 50 ppm, preferably less than or equal to 20 ppm.

The hydrocarbon fluid used according to the invention preferably comprises a content by weight of naphthenic compounds less than or equal to 1%, preferably less than or equal to 0.5% and preferably less than or equal to 500 ppm relative to the total weight hydrocarbon fluid.

According to a particularly advantageous embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins, less than 5% by weight of n-paraffins, less than 300 ppm by weight of aromatic compounds and less than 0.5% by weight of naphthenic compounds, relative to the total weight of the hydrocarbon fluid.

According to a particularly advantageous embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins, less than 5% by weight of n-paraffins, less than 0.5% by weight of compounds naphthenics and less than 100 ppm by weight of aromatic compounds, relative to the total weight of the hydrocarbon fluid.

The contents of isoparaffins, n-paraffins and naphthenes can be measured according to methods well known to those skilled in the art, for example by chromatography in gas phase. The aromatic content can be determined for example by UV spectrometry.

The hydrocarbon fluid used according to the invention has a flash point greater than or equal to 100°C, preferably greater than or equal to 120°C, preferably greater than or equal to 140°C.

Flash point can be measured according to ASTM D92 (2018).

Preferably, the hydrocarbon fluid used according to the invention has an initial boiling point and a final boiling point in the range from 150 to 400°C, preferably from 200 to 375°C, more preferably from 250 to 350°C.

The boiling range can be determined according to ASTM D86.

Preferably, the difference between the final boiling point and the initial boiling point ranges from 10 to 60°C, preferably from 25 to 45°C.

According to one embodiment, at least 90% by weight of the isoparaffins comprise from 14 to 18 carbon atoms, relative to the total weight of the isoparaffins.

According to one embodiment, the hydrocarbon fluid used according to the invention has a viscosity at 40°C ranging from 2 to 15 mm ² /s, preferably from 2.5 to 12 mm ² /s, preferably from 3 to 10 mm ² /s, more preferably 3 to 7 mm ² /s, or even 3 to 5 mm ² /s.

Kinematic viscosity at 40°C can be measured according to ASTM D445.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 90% by weight of isoparaffins and less than 500 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 100°C according to the ASTM D92 standard and a viscosity at 40°C ranging from

2 to 15 mm ² /s.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 300 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 100°C according to the ASTM D92 standard and a viscosity at 40°C ranging from

3 to 10 mm ² /s. According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 96% by weight of isoparaffins and less than 100 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60%, a flash point greater than or equal to 100°C according to the ASTM D92 standard and a viscosity at 40°C ranging from 3 to 7 mm ² /s.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 90% by weight of isoparaffins and less than 500 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60%, a flash point greater than or equal to 120°C according to standard ASTM D92 and a viscosity at 40°C ranging from 2 to 15 mm ² /s.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 300 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 120°C according to the ASTM D92 standard and a viscosity at 40°C ranging from 3 to 10 mm ² /s.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 96% by weight of isoparaffins and less than 100 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 120°C according to the ASTM D92 standard and a viscosity at 40°C ranging from 3 to 7 mm ² /s.

The hydrocarbon fluid used according to the invention has a biodegradability of at least 60% at 28 days, measured according to the OECD 301 B standard. Thus, typically, the hydrocarbon fluid according to the invention will be said to be "easily biodegradable" or " readily biodegradable” in English.

In contrast, a product will be said to be “inherently biodegradable” or “inherently biodegradable” in English, if it has a biodegradability ranging from 20 to less than 60% at 28 days according to OECD standard 301, for example according to the OECD standard. 301B.

Biodegradation of an organic chemical refers to the reduction of the complexity of chemical compounds through the metabolic activity of microorganisms. Under aerobic conditions, microorganisms transform organic substances into carbon dioxide, water and biomass. According to one embodiment, the hydrocarbon fluid used according to the invention has a biodegradability at 28 days of at least 70%, preferably at least 80%, measured according to the OECD 301 B standard.

Preferably, the hydrocarbon fluid used according to the invention has a biodegradability of at least 60% at 28 days, measured according to OECD standard 306. OECD standard 306 is more restrictive than OECD standard 301 B.

The OECD 306 method is used for the evaluation of the biodegradability of individual substances in sea water. According to this method, the hydrocarbon fluid used according to the invention typically has a biodegradability after 28 days of at least 60 %, preferably at least 70%, more preferably at least 75% and advantageously at least 80%.

According to one embodiment, the hydrocarbon fluid used according to the invention has a pour point less than or equal to -15°C, preferably less than or equal to - 20°C, more preferably less than or equal to - 30°C, even more preferably less than or equal to -40°C.

Pour point can be measured according to ASTM D97.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 90% by weight of isoparaffins and less than 500 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 100°C according to the ASTM D92 standard, a viscosity at 40°C ranging from 2 to 15 mm ² /s and a pour point less than or equal to -15°C.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 300 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 100°C according to the ASTM D92 standard, a viscosity at 40°C ranging from 3 to 10 mm ² /s, and a pour point less than or equal to -20°C.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 96% by weight of isoparaffins and less than 100 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 100°C according to the ASTM D92 standard, a viscosity at 40°C ranging from 3 to 7 mm ² /s, and a pour point less than or equal to -20°C. According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 90% by weight of isoparaffins and less than 500 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 120°C according to the ASTM D92 standard, a viscosity at 40°C ranging from 2 to 15 mm ² /s, and a pour point less than or equal to -30°C.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 300 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 120°C according to the ASTM D92 standard, a viscosity at 40°C ranging from 3 to 10 mm ² /s, and a pour point less than or equal to -15°C.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 96% by weight of isoparaffins and less than 100 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 120°C according to the ASTM D92 standard, a viscosity at 40°C ranging from 3 to 7 mm ² /s, and a pour point less than or equal to -20°C.

The hydrocarbon fluid used according to the invention typically comes from the treatment of raw materials of biological origin.

The hydrocarbon fluid used according to the invention typically has a bio-carbon content of at least 90% by weight relative to the total weight of the hydrocarbon fluid. This content is advantageously higher, in particular greater than or equal to 95% by weight, preferably greater than or equal to 98% by weight and advantageously equal to 100% by weight.

The term “bio-carbon” indicates that the carbon is of natural origin and comes from a biomaterial. Bio-carbon content and biomaterial content are expressions indicating the same value. A material of renewable origin or biomaterial is an organic material in which the carbon comes from CO2 recently fixed (on a human scale) by photosynthesis from the atmosphere. A biomaterial (100% natural carbon) has a 14C/12C isotopic ratio greater than ^10'12 , typically around 1.2 x ^10'12 , while a fossil material has a zero ratio. Indeed, the isotopic ¹⁴ C formed in the atmosphere is then integrated by photosynthesis, over a time scale of a few decades at most. The half-life of ¹⁴ C is 5730 years. Thus, materials resulting from photosynthesis, namely plants in general, necessarily have a maximum content of ¹⁴ C isotope. The determination of the biomaterial or bio-carbon content is given in accordance with ASTM D 6866, the sample being prepared for this test according to ASTM D7026.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 90% by weight of isoparaffins and less than 500 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 100°C according to the ASTM D92 standard, a viscosity at 40°C ranging from 2 to 15 mm ² /s, said fluid having a bio-carbon content of at least 90% by weight, relative to the total weight of the hydrocarbon fluid.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 300 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 100°C according to the ASTM D92 standard, a viscosity at 40°C ranging from 3 to 10 mm ² /s, said fluid having a bio-carbon content of at least 90% by weight, relative to the total weight of the hydrocarbon fluid.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 96% by weight of isoparaffins and less than 100 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 100°C according to the ASTM D92 standard, a viscosity at 40°C ranging from 3 to 7 mm ² /s, said fluid having a bio-carbon content of at least 90% by weight, relative to the total weight of the hydrocarbon fluid.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 90% by weight of isoparaffins and less than 500 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 120°C according to the ASTM D92 standard, a viscosity at 40°C ranging from 2 to 15 mm ² /s, said fluid having a bio-carbon content of at least 90% by weight, relative to the total weight of the hydrocarbon fluid.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 300 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 120°C according to the ASTM D92 standard, a viscosity at 40°C ranging from 3 at 10 mm ² /s, said fluid having a bio-carbon content of at least 90% by weight, relative to the total weight of the hydrocarbon fluid.

According to one embodiment, the hydrocarbon fluid used according to the invention comprises at least 96% by weight of isoparaffins and less than 100 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 120°C according to the ASTM D92 standard, a viscosity at 40°C ranging from 3 to 7 mm ² /s, and a pour point less than or equal to -20°C, said fluid having a bio-carbon content of at least 90% by weight, relative to the total weight of the hydrocarbon fluid.

According to one embodiment, the hydrocarbon fluid used according to the invention has a specific heat at 80°C ranging from 1 to 5 J/(g*K), preferably from 1.5 to 4 J/(g* K).

Specific heat at 80°C can be measured according to ASTM E1269.

According to one embodiment, the hydrocarbon fluid used according to the invention has a thermal conductivity at 85°C ranging from 0.05 to 0.2 W/(m*K), preferably from 0.1 to 0, 15W/(m*K).

Thermal conductivity at 85°C can be measured according to ASTM D 7896-14.

The hydrocarbon fluid used according to the invention can be obtained by a process comprising at least one catalytic hydrogenation step at a temperature of 80 to 180°C and at a pressure of 50 to 160 bars of a charge (or cut ) of deoxygenated and isomerized biological origin.

Process for obtaining the hydrocarbon fluid:

The hydrocarbon fluid used according to the invention is a hydrocarbon cut, typically resulting from the conversion of biomass.

By “hydrocarbon cut”, we mean a mixture of compounds having different boiling points.

By biomass conversion, we mean a hydrocarbon cut produced from raw materials of biological origin. Raw materials of organic origin can be chosen from vegetable oils, animal fats, fish oils and their mixtures. According to one embodiment, the process comprises a preliminary step of preparing a deoxygenated and isomerized cut by a hydrodeoxygenation step (HDO) followed by an isomerization step (ISO).

The hydrodeoxygenation (HDO) step leads to the decomposition of the structures of biological esters or triglyceride constituents, the elimination of oxygen, phosphorus and sulfur compounds and the hydrogenation of olefinic bonds. The product resulting from the hydrodeoxygenation reaction is then isomerized.

Preferably, the deoxygenated and isomerized feed of biological origin has an initial boiling point ranging from 120 to 200°C, preferably ranging from 140 to 170°C, before the hydrogenation step.

Advantageously, the fractions of interest are then subjected to hydrotreatment and then distillation steps in order to obtain the specifications of the hydrocarbon fluid used according to the invention.

This HDO/ISO process is implemented on a raw biological load, also called biomass or raw material of biological origin, selected from the group consisting of vegetable oils, animal fats, fish oils and their mixture. Suitable raw materials of organic origin are, for example, rapeseed oil, canola oil, tall or tailoil oil, sunflower oil, soybean oil, hemp oil, olive oil, flaxseed oil, mustard oil, palm oil, peanut oil, castor oil, coconut oil, animal fats such as tallow, recycled edible fats, genetically engineered raw materials, and biological raw materials produced from microorganisms such as algae and bacteria. Condensation products, esters or other derivatives obtained from raw biological materials can also serve as raw materials.

Preferably, the raw material of biological origin is an ester or a triglyceride derivative. This material is first subjected to a hydrodeoxygenation (HDO) step to decompose the structure of the constituent esters or triglycerides and eliminate oxygenated, phosphorous and sulfur compounds concomitantly with the hydrogenation of the olefinic bonds. This hydrodeoxygenation (HDO) step of the raw material of biological origin is followed by an isomerization of the product thus obtained leading to the branching of the hydrocarbon chain and an improvement in the properties of the paraffin at low temperatures.

During the HDO stage, the hydrogen and the raw material of biological origin are passed through a catalytic hydrodeoxygenation bed simultaneously, in the same direction or against the current. During the HDO stage, the pressure and temperature are between 20 and 150 bars and between 200 and 500°C respectively. Classic catalysts and Known hydrodeoxygenation methods are used during this step. Optionally, the raw material of biological origin can be subjected to pre-hydrogenation under mild conditions to avoid secondary reactions of double bonds before the H DO step. After the hydrodeoxygenation step, the product resulting from the reaction is subjected to an isomerization step (ISO) where the hydrogen and the product, and optionally a mixture of n-paraffins, are passed over catalytic beds of isomerization simultaneously, in the same direction or against the current. During the ISO stage, the pressure and temperature are between 20 and 150 bars and between 200 and 500°C respectively. Conventional and known isomerization catalysts are used during this step.

Additional secondary processes can also be implemented (such as intermediate mixing, trapping or other such processes).

Various HDO/ISO processes are described in the literature. Application WO2014/033762 describes a process comprising a pre-hydrogenation step, a hydrodeoxygenation step (HDO) and an isomerization step operated counter-currently. Patent application EP1728844 describes a process for producing hydrocarbon compounds from a mixture of compounds of plant and animal origin. This process includes a pretreatment step of the mixture to remove contaminants, such as alkali metal salts, followed by a hydrodeoxygenation (HDO) step and an isomerization step. Patent application EP2084245 describes a process for producing a hydrocarbon mixture which can be used as gas oil or in a gas oil composition by hydrodeoxygenation of a mixture of biological origin containing esters of fatty acids optionally mixed with acids. free fats, for example vegetable oils such as sunflower oil, rapeseed oil, canola oil, palm oil or tall oil, followed by hydroisomerization on specific catalysts. Patent application EP2368967 describes such a process and the product obtained by this process.

Advantageously, the raw material of biological origin contains less than 15 ppm of sulfur, preferably less than 8 ppm, preferably less than 5 ppm and more preferably less than 1 ppm according to standard EN ISO 20846. Ideally the filler does not include sulfur as a raw material of biosourced origin. The deoxygenated and isomerized feedstock from the HDO/ISO process is then hydrogenated.

The hydrogen used in the hydrogenation unit is typically highly purified hydrogen. By highly purified we mean hydrogen with a purity, for example, greater than 99%, although other grades can also be used.

The hydrogenation step is carried out using catalysts. Typical hydrogenation catalysts may be either bulk or supported and may include the following metals: nickel, platinum, palladium, rhenium, rhodium, nickel tungstate, nickel- molybdenum, molybdenum, cobalt-molybdenum. The supports can be silica, alumina, silica-alumina or zeolites.

A preferred catalyst is a nickel-based catalyst on an alumina support whose specific surface area varies between 100 and 200 m ² /g of catalyst or a nickel-based mass catalyst. The hydrogenation conditions are typically as follows:

- Pressure: 50 to 160 bars, preferably 80 to 150 bars and more preferably 90 to 120 bars;

-Temperature: 80 to 180°C, preferably 120 to 160°C and more preferably 150 to 160°C;

- Hourly volume velocity (WH): 0.2 to 5 hr ¹ , preferably 0.4 to 3 hr ¹ and more preferably 0.5 to 0.8 hr ¹ ;

- Hydrogen treatment rate: adapted to the conditions mentioned above and up to 200 Nm ³ /tons of load to be treated.

The temperature in the reactors is typically between 150 and 160°C with a pressure of approximately 100 bars while the hourly volume velocity is approximately 0.6 hr ¹ with a treatment rate adapted according to the quality of the load to be treated and parameters of the first hydrogenation reactor.

Hydrogenation can take place in one or more reactors in series. The reactors may include one or more catalytic beds. Catalytic beds are generally fixed catalytic beds.

The hydrogenation process preferably comprises two or three reactors, preferably three reactors and is more preferably carried out in three reactors in series.

The first reactor allows the trapping of sulfur compounds and the hydrogenation of essentially all unsaturated compounds and up to approximately 90% of aromatic compounds. The product from the first reactor does not contain substantially any sulfur compounds. In the second stage, that is to say in the second reactor, the hydrogenation of the aromatics continues and up to 99% of the aromatics are therefore hydrogenated.

The third stage in the third reactor is a finishing stage making it possible to obtain aromatic contents less than or equal to 500 ppm, preferably less than or equal to 300 ppm, preferably less than or equal to 100 ppm, more preferably less than or equal to 50 ppm, and ideally less than or equal to 20 ppm even in the case of products with a high boiling point, for example greater than 300°C.

It is possible to use a reactor which has two or three or more catalytic beds. The catalysts may be present in varying or essentially equal amounts in each reactor; for three reactors, the quantities according to weight can be example be 0.05-0.5/0.10-0.70/0.25-0.85, preferably 0.07-0.25/0.15-0.35/0.4-0 .78 and more preferably 0.10-0.20/0.20-0.32/0.48-0.70.

It is also possible to use one or two hydrogenation reactors instead of three.

It is also possible that the first reactor is composed of twin reactors implemented in alternative ways. This mode of operability allows in particular easier loading and unloading of the catalysts: when the first reactor includes the saturated catalyst first (substantially all the sulfur is trapped on and/or in the catalyst) it must be changed often.

A single reactor can also be used in which two, three or more catalyst beds are installed.

It may be necessary to insert quench boxes into the recycle system or between reactors to cool the effluent from one reactor to another or from a catalytic bed. to another in order to control the temperatures and the hydrothermal balance of each reaction. According to a preferred embodiment, there are no cooling or choking intermediates.

According to one embodiment, the product resulting from the process and/or the separated gases are at least partly recycled in the supply system of the hydrogenation reactors. This dilution helps to maintain the exothermicity of the reaction within controlled limits, particularly in the first stage. Recycling further allows heat exchange before the reaction and also better temperature control.

The effluent from the hydrogenation unit mainly contains the hydrogenated product and hydrogen. Flash separators are used to separate effluents into the gas phase, mainly residual hydrogen, and the liquid phase, mainly hydrogenated hydrocarbon cuts. The process can be carried out using three flash separators, one at high pressure, one at intermediate pressure and one at low pressure very close to atmospheric pressure.

The hydrogen gas that is collected at the top of the flash separators can be recycled into the hydrogenation unit feed system or at different levels in the hydrogenation units between the reactors.

According to one embodiment, the final product is separated at atmospheric pressure. It then directly feeds a vacuum fractionation unit. Preferably, the fractionation will be carried out at a pressure of between 10 and 50 mbars and more preferably at around 30 mbars. The fractionation can be carried out such that it is possible to simultaneously remove various hydrocarbon fluids from the fractionating column and their boiling temperature can be predetermined.

By adapting the feed through its initial and final boiling points, the hydrogenation reactors, separators and fractionation unit can therefore be directly connected without the need to use intermediate tanks. This integration of hydrogenation and fractionation allows optimized thermal integration associated with a reduction in the number of devices and energy savings.

Use of hydrocarbon fluid

The subject of the invention is the use of the hydrocarbon fluid defined above as a barrier fluid, in particular in double mechanical seals.

For the purposes of the present invention, the term “mechanical seals” means a device which ensures the dynamic sealing of a rotating shaft with the enclosure of the equipment which it passes through.

A mechanical seal is called “double” when it has an interior seal and an exterior seal. The process fluid is generally contained in the exterior seal.

The double mechanical seal implemented according to the invention may comprise a cavity or a chamber between the interior and exterior seals, the cavity or chamber may then comprise or be filled with the barrier fluid under pressure.

According to a preferred embodiment, the hydrocarbon fluid according to the invention is used under pressure.

The mechanical seals used in the context of the invention are preferably implemented in rotating machines, such as pumps, compressors, reactors or agitators.

The invention also relates to a double mechanical seal comprising the hydrocarbon fluid defined in the present invention, said fluid being under pressure.

Typically, the mechanical seal will also include a process fluid.

Preferably, the hydrocarbon fluid defined in the present invention will have a pressure of at least 1 bar higher than the pressure of the process fluid, more preferably, the hydrocarbon fluid defined in the present invention will have a pressure of 1 to 3 bars higher than the process fluid pressure. The hydrocarbon fluid may have one or more of the characteristics defined above in the context of the use according to the invention.

According to one embodiment, the hydrocarbon fluid under pressure is present in a cavity formed between the interior seal and the exterior seal of the mechanical seal according to the invention.

The mechanical seals according to the invention are preferably used in rotating machines, such as pumps, compressors, reactors or agitators.

EXAMPLES

In the remainder of this description, examples are given by way of illustration of the present invention and are in no way intended to limit its scope.

Table 1 describes a hydrocarbon fluid used according to the invention.

[Table 1]

The boiling point (initial and final) is determined according to ASTM D86.

The proportions of isoparaffins, n-paraffins and naphthenes are determined by gas chromatography.

The aromatic content is determined by UV spectrometry. The carbon content of biological origin is determined by ASTM D 6866, the sample being prepared according to ASTM D7026.

Table 2 below groups together the physicochemical properties of the hydrocarbon fluid used according to the invention. The properties of the fluid according to the invention are compared to a polyalphaolefin type fluid (PAO 2).

[Table 2]

* PAO 2 is said to be “inherently biodegradable”, which means that it has a biodegradability of less than 60% after 28 days according to the OECD 301 B method.

Table 2 shows that the hydrocarbon fluid used according to the invention has greater viscosity stability over a wide temperature range than polyalphaolefin type oil.

Table 2 shows that the hydrocarbon fluid used according to the invention has a low viscosity, which makes it possible to reduce internal friction and improve heat dissipation.

The thermal properties of the hydrocarbon fluid used in the example are presented in Table 3 and are compared to the PAO 2 polyalphaolefin type oil presented in Table 2. [Table 3]

Table 3 shows that the hydrocarbon fluid exhibits excellent thermal properties, as good as polyalphaolefin type oil, making the hydrocarbon fluid particularly well suited for use as a barrier fluid.

Furthermore, the hydrocarbon fluid according to the invention, in particular due to its saturated nature, is not reactive and is compatible with process fluids (in English “process fluid”).

The oxidation stability of the hydrocarbon fluid according to the invention was determined and compared to that of the PAO 2 polyalphaolefin type oil. The results are presented in Table 4.

[Table 4]

The results in Table 2 show that the hydrocarbon fluid according to the invention has better oxidation stability. It has better resistance to deposit formation and a longer service life than PAO 2 oil.

Claims

CLAIMS Use of a hydrocarbon fluid as barrier fluid, said hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 500 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard and a flash point greater than or equal to 100°C according to the ASTM D92 standard. Use according to claim 1, in which the fluid the hydrocarbon fluid has a viscosity at 40°C ranging from 2 to 15 mm ² /s, preferably from 2.5 to 12 mm ² /s, preferably from 3 to 10 mm ² /s, more preferably 3 to 7 mm ² /s, or even 3 to 5 mm ² /s. Use according to claim 1 or 2, in which the hydrocarbon fluid comprises: at least 95% by weight of isoparaffins, preferably at least 96% by weight of isoparaffins, relative to the total weight of the hydrocarbon fluid; and/or less than 5% by weight of n-paraffins, preferably less than 4% by weight of n-paraffins, relative to the total weight of the hydrocarbon fluid; and/or less than 300 ppm by weight of aromatics, preferably less than 200 ppm by weight of aromatics, even more preferably less than 100 ppm by weight of aromatics, relative to the total weight of the hydrocarbon fluid; and/or less than 1% by weight of naphthenic compounds, preferably less than 0.5% by weight of naphthenic compounds, preferably less than 500 ppm by weight of naphthenic compounds, relative to the total weight of the hydrocarbon fluid. Use according to any one of claims 1 to 3, in which the hydrocarbon fluid has a pour point less than or equal to -15°C, preferably less than or equal to -20°C, more preferably less than or equal to -30°C, even more preferably less than or equal to -40°C. Use according to any one of Claims 1 to 4, in which the hydrocarbon fluid has a flash point greater than or equal to 120°C, preferably greater than or equal to 140°C, according to the ASTM D92 standard. 6. Use according to any one of claims 1 to 5, in which the hydrocarbon fluid is obtained by a process comprising at least one catalytic hydrogenation step at a temperature of 80 to 180°C and at a pressure of 50 to 160 bars of a deoxygenated and isomerized load of biological origin.

7. Use according to any one of claims 1 to 6, in which the hydrocarbon fluid comprises at least 95% by weight of isoparaffins and less than 300 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having a biodegradability after 28 days of at least 60% measured according to the OECD 301 B standard, a flash point greater than or equal to 120°C according to the ASTM D92 standard, a viscosity at 40°C ranging from 3 to 10 mm ² / s, and a pour point less than or equal to -15°C.

8. Use according to any one of claims 1 to 7, as a double mechanical seal barrier fluid, said fluid being under pressure.

9. Double mechanical seal comprising a hydrocarbon fluid, said hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 500 ppm by weight of aromatics relative to the total weight of the hydrocarbon fluid, said fluid having biodegradability at 28 days of at least 60% measured according to the OECD 301 B standard and a flash point greater than or equal to 100°C according to the ASTM D92 standard, said hydrocarbon fluid being under pressure.

10. Double mechanical seal according to claim 9, in which the hydrocarbon fluid is as defined in any one of claims 2 to 7.