BIO-BASED ADDITIVES FOR DIESEL

Abstract

A composition useful as a fuel additive or as a fuel blend component, said composition including: aliphatic diesters: esters of aromatic monomers; and esters of short aromatic oligomers. Also disclosed are processes to make fuel additives and fuel blend component compositions.

Claims

1. A composition useful as a fuel additive, said composition comprising: aliphatic diesters: esters of aromatic monomers; and esters of short aromatic oligomers. The composition according to claim 1, wherein said aliphatic diesters are selected from the group consisting of: malonate diesters, succinate diesters; and maleate diesters.

3. The composition according to claim 1, wherein said aliphatic diesters are selected from the group consisting of: malonate diesters, succinate diesters: maleate diesters; and oxalic diesters.

4. The composition according to claim 1, wherein said aliphatic diesters are selected from the group consisting of: dibutyl esters; dipropyl esters: diethyl esters; and combinations thereof.

5. The composition according to claim 1, wherein said aliphatic diesters are dibutyl esters.

6. The composition according to claim 5, wherein said esters of aromatic monomers are esters selected from the group consisting of: oxidized derivatives of lignols.

7. The composition according to claim 6, wherein said oxidized derivatives of lignols are selected from the group consisting of: oxidized derivatives of coniferyl alcohol (3-methoxy-4-hydroxyphenylpropane: oxidized derivatives of sinapyl alcohol (3,5-dimethoxy-4-hydroxyphenylpropane and oxidized derivatives of paracoumaryl alcohol (4-hydroxyphenylpropane).

8. The composition according to claim 6, wherein said oxidized derivatives of lignols comprise ester moieties selected from the group consisting of: butyl esters: propyl esters: ethyl esters; and combinations thereof.

9. The composition according to claim 1, wherein said esters of aromatic monomers are esters selected from the group consisting of: oxidized derivatives of lignols.

10. A composition useful as a fuel additive, said composition comprising: aliphatic diesters: esters of aromatic monomers; and esters of short aromatic oligomers.

11. The composition according to claim 10, wherein said aliphatic diesters are selected from the group consisting of: malonate diesters, succinate diesters; and maleate diesters.

12. The composition according to claim 10, wherein said aliphatic diesters are selected from the group consisting of: malonate diesters, succinate diesters; maleate diesters; and oxalic diesters.

13. The composition according to claim 10, wherein said aliphatic diesters are selected from the group consisting of: dibutyl esters; dipropyl esters; diethyl esters; and combinations thereof.

14. The composition according to claim 10, wherein said aliphatic esters are dibutyl esters.

15. The composition according to claim 14, wherein said lignin-derived esters of aromatic monomers are esters selected from the group consisting of: oxidized derivatives of lignols.

16. The composition according to claim 15, wherein said oxidized derivatives of lignols are selected from the group consisting of: oxidized derivatives of coniferyl alcohol (3-methoxy-4-hydroxyphenylpropane: oxidized derivatives of sinapyl alcohol (3,5-dimethoxy-4-hydroxyphenylpropane and oxidized derivatives of paracoumaryl alcohol (4-hydroxyphenylpropane).

17. The composition according to claim 15, wherein said oxidized derivatives of lignols comprise ester moieties selected from the group consisting of: butyl esters: propyl esters: ethyl esters; and combinations thereof.

18. A process for the preparation of a fuel blend component, said process comprising the steps of: providing a light fraction of an esterified lignin-hemicellulose depolymerized organics (esterified LHDO) composition: wherein said light fraction of esterified LHDO composition is isolated via hexane or iso-octane extraction: wherein said light fraction of esterified LHDO composition comprises: aliphatic diesters; aromatic monomers; and oligomeric condensed aromatics; , admixing said light fraction of esterified LHDO composition with a hydrocarbon selected from the group consisting of: toluene and alkanes (preferably, C.sub.7-C.sub.10), more preferably, C.sub.6-alkane; C.sub.7-alkane; C.sub.8-alkane; purifying the said light fraction of esterified LHDO composition by adding an adsorbent material to the admixture at room temperature and mixing for a period of time sufficient to allow for the adsorption of minerals and insoluble organic compounds to yield a substantially aromatics-free composition, wherein said substantially aromatics-free composition comprises at least 90 by wt. % of aliphatic diester compounds comprising: malonate diesters, succinate diesters; and maleate diesters.

19. The process according to claim 18, wherein said adsorbent is selected from the group consisting of: silica; kaolin clay; bentonite clay, zeolites, and combinations thereof.

20. The process according to claim 18, wherein said step of purifying is followed by a second step of purifying using an adsorbent different from the adsorbent used in said first step of purifying.

21. The process according to claim 18, wherein said esterified lignin-hemicellulose depolymerized organics composition (LHDO) is suspended in iso-octane at a 4:1 iso-octane:LHDO weight ratio.

Description

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0070] A preferred embodiment of the present invention is prepared by the following process comprising the steps of: [0071] providing a light fraction of an esterified lignin-hemicellulose depolymerized organics (esterified LHDO) composition:
wherein said light fraction of esterified LHDO composition is isolated via hexane or iso-octane extraction; wherein said light fraction of esterified LHDO composition comprises: aliphatic diesters; aromatic monomers; and oligomeric condensed aromatics: [0072] admixing said said light fraction of esterified LHDO composition with a hydrocarbon selected from the group consisting of: toluene and alkanes (preferably, C.sub.7-C.sub.10), more preferably, C-alkane; C.sub.7-alkane; C.sub.8-alkane: [0073] purifying the said light fraction of esterified LHDO composition by adding an adsorbent material to the admixture at room temperature and mixing for a period of time sufficient to allow for the adsorption of minerals and insoluble organic compounds and to yield a substantially aromatics-free composition, wherein substantially said aromatics-free composition comprises at least 90 by wt. % of aliphatic diester compounds comprising: malonate diesters, succinate diesters; and maleate diesters.

[0074] According to a preferred embodiment of the present invention, there is provided a fuel-miscible composition prepared by a method which involves the conversion of a lignin-derived material into at least one esterified lignin derivative, said method comprising the steps of: [0075] providing said lignin-derived material which comprises: lignin monomers (20 to 50 wt. % of said lignin-derived material); lignin depolymerization products (50 to 80 wt. % of said lignin-derived material): [0076] providing an acidic composition having a pH of less than 1, said acidic composition comprising: [0077] an acid selected from the group consisting of: sulfuric acid: an alkylsulfonic acid; and an arylsulfonic acid; and [0078] an alcohol selected from the group consisting of C.sub.1-C.sub.5 linear alcohol and C.sub.3-C.sub.8 branched alcohol and mixtures thereof: [0079] combining said lignin-derived material with said acidic composition into a reaction mixture: [0080] heating up said mixture to a temperature ranging from 25 C. to 120 C.; and [0081] allowing sufficient time of reaction to convert at least a portion of said lignin-derived material into said at least one esterified lignin derivative.

[0082] According to a preferred embodiment of the present invention, the esterified LHDO is added to a separatory funnel, followed by an equal mass of solvent such as iso-octane. The resulting mixture was shaken vigorously and then left to settle and separate. The undissolved esterified LHDO was drained out of the separatory funnel and the iso-octane solution was collected. The undissolved esterified LHDO was then added back into the separatory funnel, followed by a half-portion of fresh iso-octane. Again, the mixture was shaken vigorously and then left to separate. The undissolved esterified LHDO was drained and then the iso-octane solution was collected and combined with the first fraction. The solvent was then removed to yield a light fraction of the esterified LHDO which is used in some experiments listed below.

Esterification Reaction

[0083] LHDO obtained from a delignification of lignocellulosic biomass using a modified Caro's acid as described hereinabove added to pre-weighed round bottom flask containing magnetic stir bar. Material was concentrated on a rotavap (bath temperature 50 C., vacuum gradually decreased to 1 mbar) until all volatile solvent was removed. Residue was weighed, and then the required mass of alcohol solvent was added (1:1 alcohol:LHDO by weight). The mixture was placed in an oil bath on a heating stir plate, an air condenser was attached, and the bath temperature was set to 60 C. In the LHDO, the acid is present in a concentration ranging from 30-70%, more preferably from 40-65%. More preferably, the raw LHDO has an acid content of between 40-45%. Based on these numbers, acid concentration of the reaction mixture is expected to range from 3-35% depending on the dilution factor upon combining the LHDO with the alcohol.

[0084] The reaction mixture was then stirred at the desired temperature for 16 hours. After 16 hours, the reaction mixture was removed from the oil bath, left to cool, and then filtered through a medium fritted filter to remove precipitated solids. The solids were rinsed with additional alcohol, collected, dried overnight in a 45 C. oven, and then weighed. The filtrate was concentrated on a rotary evaporator and then transferred to a separatory funnel. Water and ethyl acetate were added, and the product was extracted into the ethyl acetate phase. The organic phase was collected, and the aqueous phase was extracted two additional times with fresh ethyl acetate. The organic phases were combined and transferred back into the separatory funnel, where they were washed with two portions of a pH 2 sulfate buffer solution. The organic phase was then dried over MgSO.sub.4, filtered into a round bottom flask, and evaporated on a rotary evaporator to remove all volatiles. The residue was then weighed and the yield calculated.

Example #1: Separation of Esterified LHDO Light Fraction Using Silica Gel

[0085] An esterified LHDO light fraction was suspended in nonpolar solvent (hexanes or iso-octane) at a 5:1 solvent:LHDO weight ratio. Silica gel was then added to the suspension at a 3:1 silica:LHDO weight ratio, and the mixture was stirred vigorously for approximately 1 minute. The mixture was then filtered through a fritted funnel and rinsed with additional solvent. The filtrate was collected, solvent removed, and yield of iso-octane (or hexane) soluble LHDO was calculated.

[0086] A second fraction was then collected by resuspending the silica gel in toluene, stirring vigorously, and then filtering the mixture through a fritted filter. The silica gel was rinsed with additional toluene, and then the filtrate was collected, solvent removed, and the yield of toluene-soluble LHDO was calculated.

[0087] Finally, the silica gel was suspended in methanol and that mixture was filtered through a fritted filter to flush all remaining organics off the silica gel. The silica was rinsed with additional methanol until the filtrate ran through clear and colourless, and the silica was white. The filtrate was then collected, solvent removed, and yield of the methanol-soluble fraction calculated.

Example #2: Purification of Esterified LHDO by Exposure to Clay

[0088] An esterified LHDO light fraction was suspended in iso-octane at a 4:1 iso-octane:LHDO weight ratio. Clay (either kaolinite or bentonite) was then added at a 1:3 clay:LHDO ratio, and the mixture was stirred vigorously. The suspension was then filtered through a fritted filter and rinsed with additional iso-octane. The filtrate was collected, solvent removed, and the yield of clay-filtered esterified LHDO was calculated.

[0089] The remaining organic material absorbed by the clay was then flushed out using methanol. This flushing procedure involves the suspension of the clay in methanol and then stirring of the mixture vigorously, subsequent filtering through a fritted filter, and then rinsing with additional methanol until the filtrate becomes clear and colourless. The filtrate was collected, solvent removed, and the yield of methanol-soluble esterified LHDO portion was calculated.

Example #3: Whole Esterified LHDO

[0090] Esterified LHDO was added to a separatory funnel, followed by an equal mass of iso-octane. The mixture was shaken vigorously and then left to settle and separate. The undissolved LHDO was drained out of the separatory funnel and the iso-octane solution was collected. The undissolved LHDO was then added back into the separatory funnel, followed by a half-portion of fresh iso-octane. Again, the mixture was shaken vigorously and then left to separate. The undissolved LHDO was drained and then the iso-octane solution was collected and combined with the first fraction. A 50 g portion of the iso-octane solution was rotavapped to remove the solvent, and then the residue was weighed to determine the approximate concentration of LHDO dissolved in the iso-octane.

[0091] Using this value, clay (either kaolinite or bentonite) was added to the remaining iso-octane solution to obtain an approximately 3:1 weight ratio of LHDO:clay, and then the mixture was stirred. The mixture was then filtered through a fritted filter and rinsed with additional iso-octane. The filtrate was collected, solvent removed, and the yield of clay-filtered LHDO was calculated.

[0092] The remaining organic material absorbed by the clay was then flushed out using methanol. The clay was first suspended in methanol and then the mixture was stirred vigorously, filtered through a fritted filter, and then rinsed with additional methanol until the filtrate ran clear and colourless. The filtrate was collected, solvent removed, and the yield of methanol-soluble LHDO was calculated.

[0093] Experimental characterization tests were carried out to assess the impact of a number of preferred embodiments of the present invention in raw diesel (free from any additives) as well as commercial diesel (containing additives). Table 1 provides a list of various diesel additive parameters across several jurisdictions. Table 2 provides data obtained from experimental testing on the impact of a number of preferred embodiments of the present invention on raw diesel. Table 3 provides data obtained from experimental testing on the impact of a number of preferred embodiments of the present invention on commercial diesel.

TABLE-US-00001 TABLE 1 Various diesel additive parameters across several jurisdictions UAE/ Test Unit Canada ADNOC EU UK Japan Flash Point Deg C. >40 >65 >55 >56 >45 Sediment & Water vol % 0.02 0.05 (Centrifuge) Kinematic Viscosity @ mm.sup.2/s 1.3 to 4.1 2 to 4.5 2 to 4.5 >1.7 40Deg C. Ash Content mass % 0.01 0.01 Sulfur Content mg/kg 15 10 10 10 10 Copper Strip Corrosion NA Class 1 Class 1 Class 1 Density @ 15Deg C. g/cm.sup.3 .820-.845 .820-.845 .820-.845 Cetane Index, Proc-A NA Cetane Index NA >40 >46 >46 >45 >45 Cloud Point Deg C. 22 Carbon Residue on 10% Dist mass % 0.1 0.2 0.3 0.1 Electrical Conductivity pS/m 25 150 Lubricity HFRR @ 60 Deg C. Wear Scar Diameter m 460 460

TABLE-US-00002 TABLE 2 Parameters from raw diesel (blank) and raw diesel with an additive according to a preferred embodiment of the present invention 750 ppm 750 ppm 2.5% 2.5% 1% 1% HW Date Palm HW HW Kaoline Kaoline Toluene Kaoline Toluene isooctane Clay Clay Date Silica Clay Test Unit Blank Silica silica Hardwood Palm Fraction Fraction Flash Point Deg C. 50 49 55 56 55 57.5 52.5 Sediment & vol % <.01 <.01 <.01 <.01 <.01 <.01 <.01 Water (Centrifuge) Kinematic mm.sup.2/s 2.449 2.442 2.435 2.454 2.459 2.454 2.45 Viscosity @ 40Deg C. Ash Content mass % <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 Sulfur Content mg/kg 6.8 9.3 9.7 7.8 19 6.8 7.4 Copper Strip NA 1a 1a 1a 1a 1a 1a 1a Corrosion Density @ g/cm.sup.3 0.851 0.8546 0.8543 0.8526 0.8529 0.8512 0.8511 15Deg C. Cetane Index, NA 43.7 42.4 42.3 43.2 43.1 43.4 43.5 Proc-A Cetane Index NA 44.99 43.64 43.59 44.52 44.35 44.85 44.86 Cloud Point Deg C. 25 23 23 24 20 24 23 Carbon Residue mass % <.01 0.161 0.064 0.1 0.1 <.01 <.01 on 10% Dist Electrical pS/m <1 <1 <1 <1 46 <1 1 Conductivity Lubricity HFRR @ 60 Deg C. Wear Scar m 570 260 300 240 220 520 340 Diameter

[0094] 2.5% HW Toluene Silicarefers to esterified lignin derived from hardwood delignification which is then purified by admixing it with toluene and exposing to silica as adsorbent material (as per the procedure described hereinabove). The solvent (in this case, toluene) is then removed after the purification step. The resulting purified esterified LHDO material is added in a proportion of 2.5% to the diesel. Similarly, the sample labelled 2.5% HW Isooctane Silicarefers to esterified lignin derived from hardwood delignification purified by admixing with iso-octane using silica as adsorbent material (as per the procedure described hereinabove). The solvent (in this case, iso-octane) is then removed after the purification step. The resulting purified esterified LHDO material is added in a proportion of 2.5% to the diesel. 1% Kaoline Clay HWrefers to esterified lignin derived from a hardwood delignification purified by admixing with iso-octane using kaoline clay as adsorbent material (as per the procedure described hereinabove). The solvent (in this case, iso-octane) is then removed after the purification step. The resulting purified esterified LHDO material is added in a proportion of 1% to the diesel. 1% Kaoline Clay Date Palmrefers to esterified lignin derived from a date palm delignification purified by admixing with iso-octane using kaoline clay as adsorbent material (as per the procedure described hereinabove). The solvent (in this case, iso-octane) is then removed after the purification step. The resulting purified esterified LHDO material is added in a proportion of 1% to the diesel

TABLE-US-00003 TABLE 3 Parameters from commercial diesel (blank) and commercial diesel with an additive according to a preferred embodiment of the present invention 1% 2.5% 1% 5% HW HW Kaoline HW Isooctane Isooctane Clay Isooctane Test Unit Blank silica Silica HW/DP Silica Flash Point Deg C. 53 53 48 57 50 Sediment & Water vol % <.01 <.01 <.01 <.01 <.01 (Centrifuge) Kinematic Viscosity @ mm.sup.2/s 2.35 2.346 2.339 2.361 2.336 40Deg C. Ash Content mass % <0.01 <0.01 <0.01 <0.01 <0.01 Sulfur Content mg/kg 7.5 8.9 9.9 15 13 Copper Strip Corrosion NA 1a 1a 1a 1a 1a Density @ 15Deg C. g/cm.sup.3 0.8531 0.8544 0.8565 0.8549 0.8598 Cetane Index, Proc-A NA 42.8 42.4 41.6 42.2 40.7 Cetane Index NA 43.9 43.32 42.66 43.21 41.46 Cloud Point Deg C. 21 21 22 21 22 Carbon Residue on 10% mass % 0.04 0.048 0.15 0.2 0.28 Dist Electrical Conductivity pS/m 1128 1640 1935 1840 >2000 Lubricity HFRR @ 60 Deg C. Wear Scar Diameter m 300 290 160 220 160

[0095] 1% HW Isooctane silicarefers to esterified lignin derived from hardwood delignification purified by admixing it with isooctane using silica as adsorbent material (as per the procedure described hereinabove). The solvent (in this case, iso-octane) is then removed after the purification step. The resulting purified esterified LHDO material is added in a proportion of 1% to the diesel. 2.5% HW Isooctane Silicarefers to esterified lignin derived from hardwood delignification purified by admixing it with isooctane using silica as adsorbent material (as per the procedure described hereinabove). The solvent (in this case, iso-octane) is then removed after the purification step. The resulting purified esterified LHDO material is added in a proportion of 2.5% to the diesel. 1% Kaoline Clay HW/DPrefers to esterified lignin derived from a mixture of hardwood and date palm delignification purified by admixing it with isooctane using kaoline clay as adsorbent material (as per the procedure described hereinabove). The solvent (in this case, iso-octane) is then removed after the purification step. The resulting purified esterified LHDO material is added in a proportion of 1% to the diesel. 5% HW Isooctane Silicarefers to esterified lignin derived from hardwood delignification purified by admixing it with isooctane using silica as adsorbent material (as per the procedure described hereinabove). The solvent (in this case, iso-octane) is then removed after the purification step. The resulting purified esterified LHDO material is added in a proportion of 5% to the diesel.

[0096] The data indicates that the diesel additive according to a preferred embodiment of the present invention provides no improvement in electrical conductivity in the absence of a static dispersant, while commercial diesel which contains a static dispersant additive will generate a synergistic interaction which will boost electrical conductivity to high levels, exceeding the electrical conductivity thresholds set in various jurisdictions. The implications of this lead one to conclude that in the presence of an additive according to a preferred embodiment of the present invention one can safely reduce the loading of a anti-static component.

[0097] The data also indicates that the kinematic viscosity, density, cetane index, cloud point remain largely unaffected when a diesel additive according to a preferred embodiment of the present invention is added to either raw diesel or commercial diesel. This suggests that such an additive does not adversely impact the fuel.

[0098] Tables 4 and 5 relate data which was conducted by adding various composition according to preferred embodiments of the present invention in raw diesel.

[0099] The source from which the additive was derived is provided (hardwood, bagasse, bamboo, etc.) the filtration media used in the purification is also provided. Lastly, the concentration at which the additive is included in the diesel fuel is also indicated. The person skilled in the art will understand that an component added to a fuel is to be considered as an additive so long as its concentration in the fuel does not exceed 1% by volume. Above 1% (by volume), the component is considered to be a fuel blend component.

TABLE-US-00004 TABLE 4 Results of testing of various parameters in raw diesel of various additives and additive concentrations according to a preferred embodiment of the present invention Wear Scar Sulfur Carbon Electrical Filtration Diameter content Residue Conductivity Feedstock Media Concentration (um) (mg/kg) (mass %) (pS/m) Blank N/A N/A 570 6.8 <0.1 <1 Hardwood Bentonite 1% 190 11.0 <0.1 23 Hardwood Kaolinite 1% 240 7.8 0.1 7 Hardwood Kaolinite 750 ppm 340 6.7 <0.1 <1 Hardwood Bentonite 750 ppm 320 6.8 <0.1 <1 Hardwood Bentonite 400 ppm 360 8.0 <0.1 5 Organosolv Hardwood Bentonite 400 ppm 400 7.0 <0.1 1

TABLE-US-00005 TABLE 5 Results of testing of wear scar diameter for various feedstocks in raw diesel at a 1% additive concentration according to a preferred embodiment of the present invention Wear Scar Diameter Feedstock Filtration Media Concentration (um) Blank N/A N/A 570 Hardwood Bentonite 1% 190 Hardwood Kaolinite 1% 240 Date Palm Bentonite 1% 210 Bagasse Bentonite 1% 180 Bamboo Bentonite 1% 200 Hardwood Bentonite 1% 180 Organosolv

[0100] The data further indicates that the wear scar diameter is further improved in the presence of a diesel additive according to a preferred embodiment of the present invention. This data provides a reliable indication of the lubricity enhancement provided by the additive being tested.

[0101] According to a preferred embodiment of the present invention, the process for the preparation of a diesel fuel additive, can be tailored to yield specific types of compounds depending on the intended use of said compounds. Preferably, if the compounds sought are intended to increase the lubricity of the diesel compositions, the process will use a co-solvent such as iso-octane and kaolin clay to yield a composition comprising mainly larger aromatic compounds which are known for their lubricity when exposed to metal surfaces.

[0102] Preferably, if the compounds sought are intended to improve the combustion of diesel compositions, the process will use a co-solvent such as iso-octane and silica to yield a composition comprising mainly small diesters which are known to enhance combustion properties and reduce harmful emissions such as unburnt hydrocarbons and particulate matter by increasing the amount of oxygen in the fuel.

[0103] According to a preferred embodiment of the present invention, a first stream of aliphatic diesters as described herein may be blended with a purified second stream of condensed aromatics oligomers and aromatic monomers in a ratio which maximizes the lubricity of the additive while also maximizing the concentration of oxygenates. This allows the convenience of overcoming the hurdles posed by using the basic blend fraction (which is not distilled but rather only purified using an adsorbent as described herein) and also allows one to increase the loading of the blend component without adversely affecting the fuel parameters which are impacted by the presence of aromatics.

[0104] The embodiments described herein are to be understood to be exemplary and numerous modification and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the claims appended hereto, the invention may be practiced otherwise than as specifically disclosed herein.