Hydrodynamic Cavitation Process to Protect Catalytic Processes Used to Deoxygenate Complex Mixtures of Natural Occurring Fats & Oils Into Oxygen-Free Hydrocarbons

Abstract

The present invention relates to the production of high value bio-chemicals, in particular bio-paraffins, bio-LPG, bio-naphtha, bio-jet and bio-distillates in an integrated bio-refinery from complex mixtures of natural occurring fats & oils.

The present invention discloses a process for the production of such bio-chemicals, from natural occurring oil(s) containing acyl-containing compounds having 10 to 24 carbons including fatty acid esters and free fatty acids, and other components including impurities. Natural occurring oil(s) is(are) refined before treatment in a hydroprocessing step. The refining used in the present invention includes a hydrodynamic cavitation to remove impurities which might deteriorate the subsequent hydroprocessing step.

Claims

1.-12. (canceled)

13. A process for the production of high value bio-chemicals comprising paraffins, LPG, jet fuel, diesel and naphtha, from natural occurring oil(s) containing acyl-containing compounds having 10 to 24 carbons including fatty acid esters and free fatty acids, and other components including impurities, comprising the steps of: (a) refining the natural occurring oil(s) to remove at least a part of the impurities and to obtain a refined oil, (b) optionally pre-treating the refined oil to further remove impurities and to obtain a pre-treated oil, (c) hydroprocessing the refined oil or the pre-treated oil in presence of dihydrogen and of at least one catalyst to transform fatty acid esters and free fatty acids contained in said refined oil or pre-treated oil into linear or substantially linear paraffins, where the hydroprocessing is chosen among hydrodeoxygenation, decarboxylation and decarbonylation, characterized in that the refining step (a) includes a hydrodynamic cavitation processing of the natural occurring oil(s) in presence of water under conditions efficient to generate cavitation features and to transfer at least a part of impurities contained in the natural occurring oil(s) into an aqueous phase, and separating the aqueous phase from an oil phase and recovering the oil phase as a refined oil.

14. The process according to claim 13 wherein the natural occurring oil(s) contain(s) one or several oils chosen among vegetable oil, animal fat, waste oils, by-products of the refining of vegetable oil(s) or of animal oil(s) containing free fatty acids, tall oils, and oil produced by bacteria, yeast, algae, prokaryotes or eukaryotes.

15. The process according to claim 13, characterised in that at least one degumming agent is added to the natural occurring oil(s) in the hydrodynamic cavitation processing step.

16. The process according to claim 15, characterized in that the degumming agent is chosen among water, steam, acids and complexing agents.

17. The process according to claim 13, characterised in that the pre-treatment performed at step b) is chosen among a bleaching process in which the refined oil is contacted with an absorbent, a process in which the refined oil is contacted with an ion-exchange resin, a mild acid wash of the refined oil, a process using guard-beds, filtration, solvent extraction.

18. The process according to claim 13, characterised in that it further comprises hydrolysing the refined oil or pre-treated oil to transform fatty acid esters contained into the refined oil or pre-treated oil into alcohols and free fatty acids, sending to the hydroprocessing step, in particular directly, the free fatty acids after alcohols removal.

19. The process according to claim 13, characterised in that said at least one catalyst of the hydroprocessing step is chosen among a hydrogeoxygenation catalyst, a decarbonylation catalyst and a decarboxylation catalyst.

20. The process according to claim 13, characterised in that it further comprises: (d) submitting at least a part of the linear or substantially linear paraffins from step c) to a hydrocracking—hydroisomerisation reaction in presence of dihydrogen and of at least one catalyst to obtain an effluent and fractionating said effluent into dihydrogen, LPG, naphtha, Jet fuel and diesel fractions.

21. The process according to claim 13, characterised in that a light fraction comprising C4-C15 hydrocarbons, is added to the natural occurring oil(s) in the hydrodynamic cavitation processing step.

22. The process according to claim 21, characterised in that the light fraction is a naphtha fraction, optionally recovered from the fractionation of the effluent from the hydrocracking—hydroisomerisation step (d).

23. The process according to claim 13, characterised in that a gas stream comprising dihydrogen, carbon dioxide, dihydrogen sulfide, methane, ethane, propane or mixtures thereof, is added to the natural occurring oil(s) in the hydrodynamic cavitation processing step.

24. The process according to claim 13, characterised in that it further comprises: (e) submitting at least a part of the linear or substantially linear paraffins from step c) to a steamcracking reaction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0260] FIG. 1 represents table 1.

[0261] FIG. 2 schematically represents units used to carry out the process according to various particular embodiments of the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0262] FIG. 2 demonstrates the different processing units and intermediate product streams of an embodiment of the present invention.

[0263] In the present description, “hydrogen” stands for “dihydrogen”.

[0264] Raw (crude) fats & oil (2) coming from a production unit (not represented) where oil-bearing feedstock's are rendered and extracted to obtain the raw fats & oils (1). These raw fats & oils (2) are sent to a hydrodynamic cavitation unit (4) to degum the raw fats & oils (1). Hereto, water, acids and/or complexing agents are added to the raw fats & oils (3). Typical acids are phosphoric acid, sulphuric acid and typical complexing weak organic acids are acetic, citric, maleic, oxalic acid or EDTA. According to the nature of the phosphatides, the amount of water and acid or complexing agents is adjusted.

[0265] Optionally before the hydrodynamic cavitation, a water degumming (not represented) can be added to remove at least partially the hydratable phosphatides and partially metal-containing compounds.

[0266] After the hydrodynamic cavitation step the gums (6) and the aqueous phase (8) are separated by filtration, decantation and centrifugation (5).

[0267] Eventually the obtained refined fats & oils (9) can be dried by vacuum distillation techniques.

[0268] The raw fats & oils that are treated in the hydrodynamic cavitation device (4) can be recycled back partially (7) to the inlet of the hydrodynamic cavitation device (4) in order to improve the degumming process. To this recycle stream (7) additional water, acids and/or complexing agents can be added.

[0269] As an alternative operation multiple hydrodynamic cavitation devices can be put in series and/or in parallel Optionally the degumming can be further improved by recycling part of the degummed fats & oils (8) back to the inlet of the hydrodynamic cavitation device (4). To this recycle stream (8) additional water, acids and/or complexing agents can be added.

[0270] Degummed oil (9) is obtained. When the phosphorous and other metals concentration is low enough in order not to plug the preheatment section, solid catalyst bed or not to poison the downstream solid catalyst, the degummed oil constitute the refined fats & oils (10).

[0271] Optionally, when the phosphorous and other metals concentration is not low enough in order not to plug the preheatment section, solid catalyst bed or not to poison the downstream solid catalyst the degummed oil can be further pre-treated, here bleached (11) and the bleached product constitutes the refined fats & oils (10). In the bleaching step adsorbents like activated clays, amorphous silica gels or activated carbon are used to adsorb remaining phosphatides and order metal compounds. The adsorbents is removed and disposed of (12). This optional bleaching may be replaced or complemented by the other pre-treatments previously mentioned.

[0272] The refined fats & oils (10) are sent to the hydrodeoxygenation, decarboxylation, decarbonylation step that includes solid catalysts (20). A dihydrogen containing stream is added to this step (21).

[0273] After the hydrodeoxygenation, decarboxylation, decarbonylation step the non-condensables, like propane, CO.sub.2 and dihydrogen are flashed off (22) the condensable liquid paraffin's. Also any produced liquid water is removed (22).

[0274] The non-converted dihydrogen is recovered and optionally recycled back to the inlet of the hydrodeoxygenation, decarboxylation, decarbonylation step (23).

[0275] The obtained paraffins (24) have essentially the same number of carbons as the acyl-moieties of the original fats & oils in case the reaction mechanism is purely hydrodeoxygenation and the obtained paraffins (24) have essentially one carbon less as the acyl-moieties of the original fats & oils in case the reaction mechanism is purely decarboxylation or decarbonylation.

[0276] The obtained bio-paraffin's (24) can be used as steamcracker feedstock (30).

[0277] The obtained bio-paraffin's (24) can further be treated to improve its cold-flow properties by hydrocracking—hydroisomerisation (40) by adding a dihydrogen containing steam (41) and sending the mixture over a hydrocracking—hydroisomerisation solid catalyst (40). The product of the hydrocracking—hydroisomerisation (50) is fractionated (42) into dihydrogen, LPG, naphtha, Jet fuel and diesel fractions. Optionally the dihydrogen stream is recycled back to the hydrocracking—hydroisomerisation section (43). Optionally, a part of the naphtha fraction can be recycled back to the inlet of the hydrodynamic cavitation device (not represented). To this recycle stream additional water, acids and/or complexing agents can be added. Optionally, a part of the dihydrogen is combined with the feed entering the hydrodynamic cavitation device.

[0278] The hydrocarbon fractions (50) can be used as transportation fuels (60) or can be used as special fluids (70). The applications of the special fluids are as propellant, paraffinic solvent or cooling fluids.

[0279] By applying hydrodynamic cavitation to the raw fats & oils to remove essentially most of the phosphorous and metal-containing compounds, the present invention allows protecting the hydrodeoxygenation or decarboxylation/decarbonylation section including a preheating section and a solid catalyst section.

EXAMPLES

[0280] Examples 1-4 have been performed using a laboratory hydrodynamic cavitation device fabricated by installing a Venturi tube in a hydrodynamic cavitation setup equipped with a pump at the inlet and a pressure controller at the outlet. The Venturi tube has an orifice opening (throat diameter) of 0.75 mm and an orifice length (throat length) of 1 mm, a wall of 25° inclination (related to the flow axe) at the inlet (convergent section) and a wall of 6° inclination (related to the flow axe) at the outlet (divergent section). The pipes to the Venturi convergent and divergent sections have a diameter of 5 mm and a length of 50 mm.

[0281] The phosphorus content of raw rapeseed and hydrodynamic cavitation processed product has been measured by means of ICP (Inductive Coupled Plasma).

Ex. 1

[0282] Raw rapeseed oil (10 kg) was mixed with 2 wt % water, well mixed and pressure increased with the aid of the pump in order to have a ratio outlet pressure to inlet pressure of less than 0.75. At an outlet pressure of 2 bars the mixture rapeseed oil and water was passed through the hydrodynamic cavitation device at 40° C. While the raw rapeseed oil had a phosphorus content of 811 wppm the rapeseed product after cavitation treatment and separation of the aqueous phase by centrifugation, has a phosphorus 1.0 content of 26 wppm.

Ex. 2

[0283] The raw rapeseed oil (10 kg) was mixed with 2 wt % of a water solution containing 10 wt % of citric acid (0.2 wt % citric acid on oil basis) and stirred vigorously for 30 minutes. The pressure was increased with the aid of the pump in order to have a ratio outlet pressure to inlet pressure of less than 0.75. At an outlet pressure of 2 bars the mixture rapeseed oil and water was passed through the hydrodynamic cavitation device at 40° C. While the raw rapeseed oil had a phosphorus content of 811 wppm the rapeseed product after cavitation treatment and separation of the aqueous phase by centrifugation, has a phosphorus content of 1 wppm.

Comparative Ex. 3

[0284] Raw rapeseed oil (10 kg) was mixed with 2 wt % water, well mixed and heated to 65° C. during 30 minutes in a lab vessel at a stirring speed of 500 rpm. The aqueous phase was separated by centrifugation. The phosphorus content has dropped from 811 wppm to 120 wppm.

Comparative Ex. 4

[0285] Raw rapeseed oil (10 kg) was mixed with 2 wt % of a water solution containing 10 wt % of citric acid (0.2 wt % citric acid on oil basis), well mixed and heated to 65° C. during 30 minutes in a lab vessel at a stirring speed of rpm. The aqueous phase was separated by centrifugation. The phosphorus content has dropped from 811 wppm to 51 wppm.

Ex. 5

[0286] In a small pilot unit, a nickel-molybdenum on alumina catalyst was loaded and presulphurised with DMDS/SRGO mixture under dihydrogen. The product of example 2, having only 1 wppm of remaining phosphorus was processed in order to deoxygenate the triglycerides at about 275° C. and 80 barg (hydrogen to liquid ratio of 900 Nl/l). The LHSV was 1 h.sup.−1. Nearly full deoxygenation could be reached during more than 1000 hours on stream without any deactivation nor plugging of the pilot unit.

Comparison Ex. 6

[0287] In the same small pilot unit, the product of example 4, having still 51 wppm of remaining phosphorus was processed in order to deoxygenate the triglycerides at about 275° C. and 80 barg (hydrogen to liquid ratio of 900 Nl/l). The LHSV was 1 h.sup.−1. Nearly full deoxygenation could be reached during only 20 hours on stream after which plugging of the pilot unit started with increase of inlet pressure. Semi-quantitative analysis (about 10% error) by means of XRF (X-ray fluorescence spectroscopy) showed that the material constituting the plug was significantly enriched in phosphorus (more than 2000 wppm) compared to only 51 wppm in the feedstock.