Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/48—Separation; Purification; Stabilisation; Use of additives
  • C07C67/52—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
  • C07C67/54—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation by distillation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
  • B01D3/34—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping with one or more auxiliary substances
  • B01D3/343—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping with one or more auxiliary substances the substance being a gas
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L1/00—Liquid carbonaceous fuels
  • C10L1/02—Liquid carbonaceous fuels essentially based on components consisting of carbon, hydrogen, and oxygen only
  • C10L1/026—Liquid carbonaceous fuels essentially based on components consisting of carbon, hydrogen, and oxygen only for compression ignition
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
  • C11C1/00—Preparation of fatty acids from fats, fatty oils, or waxes; Refining the fatty acids
  • C11C1/08—Refining
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
  • C11C1/00—Preparation of fatty acids from fats, fatty oils, or waxes; Refining the fatty acids
  • C11C1/08—Refining
  • C11C1/10—Refining by distillation
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G2300/00—Aspects relating to hydrocarbon processing covered by groups C10G1/00 - C10G99/00
  • C10G2300/10—Feedstock materials
  • C10G2300/1011—Biomass
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E50/00—Technologies for the production of fuel of non-fossil origin
  • Y02E50/10—Biofuels, e.g. bio-diesel
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P30/00—Technologies relating to oil refining and petrochemical industry
  • Y02P30/20—Technologies relating to oil refining and petrochemical industry using bio-feedstock

Definitions

• BIODIESEL PROCESS FOR PURIFYING BIODIESEL FROM A
• the present invention relates to a device and a process for the removal of a by-product or compound related to the manufacture of biodiesel, to a process for purifying biodiesel from a transesterification step, and to a plant for production of biodiesel including said device and allowing the implementation of said methods.
• Transesterification is the classic technique for producing biodiesel. It is a process in which oils, which may be vegetable oils, cooking oils, animal fats and / or microalgae oils, are mixed with an alcohol (usually ethanol). or methanol) in the presence of a catalyst (usually sodium or potassium hydroxide) to form fatty esters
• the products resulting from this reaction can be separated into two liquid phases: a first phase comprising an aqueous solution of glycerol and a second phase comprising predominantly the desired ester, that is to say biodiesel.
• a first phase comprising an aqueous solution of glycerol
• a second phase comprising predominantly the desired ester, that is to say biodiesel.
• this separation in liquid phases facilitates the removal of glycerol, a sub-component.
• industrial product used in the chemical, cosmetic and pharmaceutical industry then allows the removal of traces of unreacted alcohol, catalyst and soaps produced by saponification of fatty acids in the residual liquid alcohol / ester phase during the transesterification step.
• cleaning or purification of the esters is carried out by washing with water, drying under vacuum and filtration.
• Vacuum in these stripping columns is achieved through vacuum pumps.
• This rotating part equipment results in considerable power consumption and inherent operational and reliability problems, which result in high maintenance costs and possibly failures that can cause the unit to shut down.
• the applicant Company has found that it is possible to satisfy these requirements by substituting or adapting the vacuum stripping column, and eliminating the associated pump, by a device comprising: a stripping column at atmospheric pressure or greater than atmospheric pressure, advantageously supplemented by a "cryogenic trap" type exchanger.
• the main advantage of the invention is therefore the removal of the vacuum pump equipment.
• Other advantages of the present invention are a sharp reduction in electricity consumption in the stripping columns and a large reduction in the size of the compressors used in the columns.
• the term "stripping" refers to a separation of a light component of biodiesel in a column in which the biodiesel and the stripping gas flow countercurrently.
• cryogenic trap designates a device that allows the condensation of the vapors contained in the product by passing through a bath of cryogenic fluid
• co-current hydro-ejector designates a liquid jet gas compressor for drawing a gas into a pressurized liquid.
• the subject of the present invention is therefore a device for removing a by-product or a biodiesel compound resulting from a transesterification stage, comprising a stripper column at a higher pressure or also at the atmospheric pressure in which the biodiesel circulates. and a stripping gas, the column being connected to a means for recovering said by-product from the stripping step, characterized in that the compound is methanol or ethanol or water, and that the device comprises at least one source of stripping gas composed mainly of nitrogen, CO 2 or their mixtures.
• It will be preferably at atmospheric pressure or a few hundred millibars above atmospheric pressure, for example because of the intervention of a booster upstream.
• a gas consisting of nitrogen, CO 2 or their mixture, but it is possible to envisage having to work with non-pure gases such as resulting, for example, from recycling operations, in any case.
• the term "majority” should be understood to include at least 80% of the target gas or mixture, and even more preferably at least 90% or even 99% of the target gas or mixture.
• the column is advantageously connected to a "cryogenic trap" type exchanger (as will be seen below, other means of capture or recovery are possible according to the invention, even if the cryogenic coin type exchanger is the means preferred here).
• a cryogenic trap type exchanger
• several devices according to the invention can be implemented successively.
• a device can be implemented for the removal of alcohol and will be followed by a second device for the removal of water, that is to say, drying.
• cryogenic trap type exchanger is fed with a cryogenic fluid selected from the group comprising liquid nitrogen and / or carbon dioxide.
• cryogenic trapping solution another technical solution of capture, such as an adsorption solution on activated carbon fabric. or even a combination of several techniques, for example a coupling of a cryogenic trapping solution with an absorption solution on activated carbon fabric.
• nitrogen is already a required component in the production of biodiesel, so it is advantageous.
• the nitrogen can be used in particular: for the inerting of the vegetable oils before treatment, to prevent their oxidation in contact with air and its degradation by contact with moisture, for the inerting of the biodiesel, to avoid degradation by oxidation and moisture, for the inerting of storage and methanol or transesterification ethanol lines for reasons of flammability, and
• instrument gas for supplying, for example, pneumatically controlled valves. Therefore, it is advantageous to use nitrogen in the biodiesel by-product removal process.
• Mixtures of nitrogen-C0 2 may also be used according to the invention as stripping gas.
• the device according to the invention also comprises means for heating at least a portion of the cryogenic fluid and to bring it to the stripping column to be used as a stripping gas.
• the biodiesel is circulated countercurrently with the stripping gas which may be a part of the cryogenic fluid having been reheated.
• the heating means of a portion of the cryogenic fluid may be constituted by at least one heat exchanger allowing a heat exchange between the biodiesel by-product from the stripping going to the cryogenic trap and the cryogenic fluid.
• the device according to the invention may also comprise a capacitor receiving said biodiesel byproduct from the stripping column before it passes into the cryogenic trap.
• This capacitor allows a first separation between the by-product which appears in the liquid phase and the stripping gas. This first separation thus makes it possible to limit the amount of by-product passing through the cryogenic trap. Subsequently, a second separation will take place, for example in a cryogenic trap, to remove residual residual impurities of the byproduct that occurs in the gas phase of the stripping gas.
• the device according to the invention further comprises a recycling fan or a co-current hydro-ejector which will be used for the stripping gas, freed from residual impurities after passing through the cryogenic trap. , either recycled and returned to the stripping column.
• This recirculating fan or hydro-ejector co-current may be used including, but not exclusively, in the so-called "closed-loop" unit defined below.
• the subject of the invention is also a process for the removal of a biodiesel compound resulting from a transesterification step, the compound being methanol or ethanol or water, characterized in that it comprises: the stripping at a pressure greater than or equal to the atmospheric pressure of the biodiesel in a stripping column using a stripping gas mainly comprising nitrogen, or CO 2 or mixtures thereof, and
• the recovery step is performed using a "cryogenic trap" type exchanger.
• the recovery of said by-product is conducted by condensation and cryogenic trapping of the gas phase resulting from this condensation.
• cryogenic fluid and the stripping gas are of the same nature. They are for example selected from the group consisting of carbon dioxide or nitrogen and mixtures thereof.
• cryogenic trapping solution another technical solution of capture, such as an adsorption solution on activated carbon fabric, or even a combination of several techniques, for example a coupling of a cryogenic trapping solution with an absorption solution on activated carbon fabric.
• the process for removing a by-product according to the invention further comprises the recycling of the stripping gas (for example nitrogen , CO 2 or a mixture) via a recirculation fan or a co-current hydro-ejector.
• the stripping gas for example nitrogen , CO 2 or a mixture
• the method according to the invention is called a "closed loop” when it comprises the subsequent step of recycling the stripping gas via a recycling fan or a co-current hydro-ejector, while it says to " open loop "when he does not understand this subsequent recycling step.
• the elimination process according to the invention may further comprise heating at least a portion of the cryogenic fluid prior to its use in the column of stripping (open loop) or heating the stripping gas free of residual impurities at the outlet of the cryogenic trap (closed loop).
• the invention also relates to a process for purifying biodiesel resulting from a transesterification which comprises: the stripping at a pressure greater than or equal to atmospheric pressure of the biodiesel in the stripping column using a gas of stripping,
• Drying can be carried out by stripping at higher pressure or also at atmospheric pressure of the biodiesel obtained from the washing step and then recovering the water from the stripping using the cryogenic trap, that is to say at using the disposal method according to the invention.
• the biodiesel purification process comprises the recovery of said by-product resulting from the stripping step as well as the elimination of the water by means of the elimination process and of the device described above.
• the alcohol removal step is conducted with a closed loop using a recirculation fan and the drying step is carried out with a closed loop at the end of the cycle. using a co-current hydro-ejector.
• the biodiesel purification process includes the closed loop alcohol removal step and the open loop drying step and either the open loop elimination step and the closed loop drying step.
• the invention also further relates to a biodiesel production plant, comprising a biodiesel transesterification unit, an alcohol elimination unit comprising an elimination device according to the invention and a washing unit and a elimination of water (drying) comprising an elimination device according to the invention.
• FIG. 1 is a schematic view of a biodiesel production installation according to the prior art
• FIG. 2 is a diagrammatic view of a biodiesel production facility according to the invention
• FIG. 3 is a schematic view of an open-loop elimination unit of biodiesel by-products according to the invention
• Figure 4 is a schematic view of a closed-loop elimination unit of biodiesel by-products according to the invention.
• methanol will be used in what follows, although other alcohols and water may be eliminated in the same way.
• liquid nitrogen will be used in the following description, while other cryogenic fluids may be used.
• FIG. 1 there is shown a biodiesel production facility according to the prior art.
• This facility includes a transesterification unit (IA), an alcohol removal unit (IB) and a water washing and removal (drying) unit (IC) from biodiesel.
• the alcohol elimination unit (IB) allows the recovery of the reagent having been used for transesterification by means of a vacuum stripping column (1) with associated pump (2).
• the water washing and removal unit (IC) also comprises a vacuum stripping column (3) with associated pump (4).
• FIG. 2 there is shown a plant for producing biodiesel according to the invention.
• This facility includes a transesterification unit
• (2B) comprises an atmospheric pressure stripping column (7) connected to a "cryogenic trap” type exchanger (12) and may include a recirculation fan (17) as part of the "closed loop” process.
• the unit for washing and removing water (2C) (ie drying) also comprises an atmospheric pressure stripping column connected to a "cryogenic trap” type exchanger and may comprise a co-current hydro-ejector as part of the "closed loop” process.
• FIG. 3 shows a unit (2B) for open-loop removal of methanol from biodiesel.
• Unit (2B) is adapted to remove methanol from biodiesel from a transesterification step (2A).
• Biodiesel, coming from the reactor (5) after trans-esterification, is preheated to between 120 and 150 ° C. in a heat exchanger (6) before being introduced into the stripping column (7).
• the stripping nitrogen is loaded with the excess methanol removed from the biodiesel.
• This stripping nitrogen charged with methanol is subsequently cooled in a second heat exchanger (8) and placed in a condenser (9).
• a liquid phase ie most of the methanol by-product (10) is recovered on the one hand and a gaseous phase (ie stripping nitrogen containing trace amounts of methanol) on the other hand.
• a gaseous phase ie stripping nitrogen containing trace amounts of methanol
• the remaining traces of methanol (11) from the gas phase from the condenser are then trapped in a liquid nitrogen-supplied (13) cryogenic trap (12) which is used for the proper nitrogen requirements. at the factory.
• the stripping nitrogen thus recovered without a trace of methanol can then be returned to the other zones of the plant in order to be used in particular as an inerting gas (14).
• This unit is called "open loop" since the stripping nitrogen thus recovered without trace of methanol is returned to the plant (ie inerting), while the liquid nitrogen having fed the cryogenic trap, will be used to feed again the stripping column.
• FIG. 4 shows a unit (2B ') for closed-loop elimination of methanol from biodiesel.
• This unit (2B ') is adapted to remove methanol, from biodiesel resulting from a transesterification step (2A). Biodiesel, coming from the reactor
• cryogenic trap (12) which is used for the proper nitrogen requirements. at the factory.
• the stripping nitrogen thus recovered without a trace of methanol can then be returned to the stripping column to supply said stripping column again via a recycling fan (17).
• the liquid nitrogen fed to the cryogenic trap will be directed to the plant (16).
• An additional nitrogen supply can be made to fill the losses (18).
• the biodiesel coming from the reactor after transesterification (a) is preheated to between 120 and 150 ° C. before being introduced (b) into the nitrogen stripping column.
• the biodiesel is cooled (c) and directed to the water washing and removal unit (d).
• the stripping nitrogen charged with excess methanol it is directed (f) to the alcohol removal unit.
• the alcohol removal unit After a first temperature condensation of the cooling water, most of the methanol is recovered in liquid form (10).
• the remaining traces of methanol in the stripping nitrogen are then directed (g) and trapped in a "cryogenic trap" type exchanger fed with liquid nitrogen. This liquid nitrogen having fed the cryogenic trap, returns to the stripping column (h), while the stripping nitrogen thus recovered without trace of methanol is returned to the factory (i).
• the material, energy (nitrogen and heat) and cost savings for this aspect of the invention are as follows:
• the outlet temperature of the cryogenic trap (i) has been adjusted according to the material balance, and it could further fall according to the methanol content criteria of the inerting nitrogen.
• An example of overall nitrogen consumption for a biodiesel purification plant is 26 tonnes / day of nitrogen for a production of 250,000 tonnes / year of biodiesel.
• Nitrogen required for plant needs kg / hr 433
• An economic balance sheet (Table 5) can be established for electricity consumption, maintenance costs and water vapor costs.
• the method according to the invention "open loop" thus allows a gain of 8498 C / year compared to the method of the prior art.
• the biodiesel coming from the reactor after transesterification (j), is preheated to between 120 and 150 ° C. before being introduced (k) into the column of stripping with nitrogen.
• the biodiesel is cooled (1) and directed to the water washing and removal unit (m).
• the stripping nitrogen charged with excess methanol it is directed (o) to the alcohol removal unit.
• the alcohol removal unit After a first temperature condensation of the cooling water, most of the methanol is recovered in liquid form (10). The remaining traces of methanol in the stripping nitrogen are then directed (p) and trapped in a heat exchanger.
• An example of overall nitrogen consumption for a biodiesel facility is 26 tonnes / day of nitrogen for a production of 250,000 tonnes / year of biodiesel.
• the amount of nitrogen to be vaporized in the cryogenic trap corresponds to the amount of nitrogen already vaporized for the consumption of the plant (inerting).
• the balance sheet of Table 8 shows a variation of heat consumption in the opposite direction in the two units with the method according to the invention: positive in the case of the elimination of methanol and negative in the case of drying. This increase in heat consumption in the case of water removal or drying is the consequence of the need for heat for the preheating of nitrogen. Overall, in the purification process according to the invention, the steam consumption is lower than that of the conventional method.
• the method according to the invention "closed loop" thus allows a gain of 16547 € / year compared to the method of the prior art.
• the operating cost balance is therefore advantageous for the proposed nitrogen stripping column solution when compared to the existing vacuum column solution.

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• 2007
  • 2007-06-14 FR FR0755752A patent/FR2917420B1/fr active Active
• 2008
  • 2008-06-05 EP EP08805940A patent/EP2158017A2/de not_active Withdrawn
  • 2008-06-05 WO PCT/FR2008/051003 patent/WO2009004206A2/fr not_active Ceased

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