MXPA00002187A - Emulsion blends - Google Patents

Abstract

Emulsion blends are provided containing Fischer-Tropsch hydrocarbons, non-Fischer-Tropsch hydrocarbons, water, and a surfactant.

Description

EMULSION MIXES FIELD OF THE INVENTION The present invention relates to emulsions comprising Fischer-Tropsch derivative liquids and hydrocarbon liquids other than Fischer-Tropsch liquids, for example petroleum liquids and water. BACKGROUND OF THE INVENTION Hydrocarbon emulsions in water emulsions are well known and have a variety of uses, for example as fuels for power plants or internal combustion engines. These emulsions are generally described as macroemulsions, that is, when the emulsion is cloudy or cloudy or opaque, in comparison to icroemulsions that are essentially clear, translucent and more thermodynamically stable than the macroemulsions, the microemulsions have a higher surfactant level. While aqueous fuel emulsions that reduce contaminants when burned as fuels are known, methods for preparing emulsions and the materials employed therein, for example, surfactants and co-solvents such as alcohols, can be expensive. Also, the thermodynamic stability of the acro-emulsions is relatively weak, particularly when low levels of surfactants are used to prepare the emulsions. Consequently, there is a need for stable macroemulsions that employ less surfactants or cosolvents, and use less expensive materials when preparing hydrocarbon emulsions in water. Additionally, by virtue of the invention described herein, distillate fuel emulsions of conventional petroleum fuels can be improved, for example at a higher cetane number, by mixing Fischer-Tropsch derivative hydrocarbon liquids, for example, distillates. For purposes of this invention, the stability of macro-emulsions is generally determined as the degree of separation that occurs over a twenty-four hour period, usually the first twenty-four hour period after the emulsions are formed. SUMMARY OF THE INVENTION According to this invention, there is provided a distilled emulsion comprising water, a Fischer-Tropsch hydrocarbon, a hydrocarbon other than a Fischer-Tropsch hydrocarbon, and a surfactant when the amount of surfactant employed is less than or equal to preferably less than, the amount of surfactant required to emulsify either hydrocarbon by itself. In this way, a synergistic effect occurs when hydrocarbon distillates other than Fischer-Tropsch are emulsified with water in the presence of Fischer-Tropsch hydrocarbon distillates. BRIEF DESCRIPTION OF THE DRAWING Figure 1 is a graph of a minimum amount of surfactant required (ordinate) to emulsify mixtures of Fischer-Tropsch distillates and conventional petroleum distillates (abscissa). PREFERRED MODALITIES By virtue of this invention, relatively stable macro-emulsions are prepared in substantial absence, for example < 1.0% by weight or complete absence of the addition of a co-solvent, for example alcohols and preferably in the substantial absence of co-solvent. In this manner, Fischer-Tropsch liquids may contain trace amounts of oxygenates, including alcohols, these oxygenates are lower in concentration of the emulsions than would be present if an alcohol or other oxygen-containing co-solvent was added to the emulsion. In general, the alcohol content of Fischer-Tropsch liquids is zero in the sense of not being measurable and in general is less than about 1% by weight based on liquids, more preferably less than about 0.1% by weight based on in the liquid. The Fischer-Tropsch liquids employed in this invention are those hydrocarbons that are liquid at room temperature. In this way, these materials can be liquids as raw material from the Fischer-Tropsch hydrocarbon synthesis reactor, such as C4 + liquids, preferably C5 + liquids, more preferably liquids containing C5-C17 hydrocarbons., or hydroisomerized Fischer-Tropsch liquids such as C5 + liquids. These materials generally contain at least about 90% by weight paraffins, normal or isoparaffins, preferably at least about 95% by weight paraffins, and more preferably at least about 98% by weight paraffins. Fischer-Tropsch hydrocarbons can also be characterized as fuels: for example, naphthas, for example boiling in the range of C4 to approximately 160 ° C (320 ° F), preferably C5-160 ° C (320 ° F), emulsions of water which can be used as fuel for power plants; transport fuel, fuel for combustion turbines, for example boiling in the range of approximately 121-301 ° C (250 - 575 ° F), preferably 149-288 ° C (300 - 550 ° F) and diesel fuels, for example they boil in the range of approximately 160-371 ° C (320 - 700 ° F). Other liquids derived from Fischer-Tropsch materials, and having higher boiling points, are also included in the materials used in this invention.

The non-Frischer-Tropsch hydrocarbons can be obtained from a variety of sources, for example petroleum, schist liquids (kerogen), tar sand liquids (bitumen), or mineral carbon liquids. Preferred materials are petroleum hydrocarbons boiling in the same ranges as described for liquids containing Fischer-Tropsch hydrocarbons. In general, the emulsions contain less than 100% by weight already of liquids containing Fischer-Tropsch hydrocarbons or liquids containing non-Fischer-Tropsch hydrocarbons. Preferably, however, Fischer-Tropsch liquids are present in amounts of about 10-90% by weight of total hydrocarbons, more preferably at least about 20% by weight of Fischer-Tropsch liquids, still more preferably 25-75% by weight and still more preferably 40-60% by weight of Fischer-Tropsch liquids. The amount of water and total hydrocarbons in the emulsions can also vary over a wide range, for example 90/10 hydrocarbons / water to 10/90 hydrocarbons / water. Preferably, however, the hydrocarbon content will be greater than about 50% by weight, preferably greater than about 60% by weight, especially 60-85% by weight.

While any type of water can be used, the water obtained from the Fischer-Tropsch process, for example 2nH2 + nCO = »CHnH2n + 2 + nH20 is particularly preferred, the process water of a process without displacement. A generic composition of the process water Fischer-Tropsch, where the oxygenates are preferably < 2.0% by weight, more preferably less than 1% by weight and useful for preparing hydrocarbon emulsions, are illustrated below: alcohols with 1 to 12 carbon atoms 0.05-2% by weight, preferably 0.05-1.2% by weight acids with 2 to 6 carbon atoms 0 - 50 wppm ketones, aldehydes, acetates with 2 to 6 carbon atoms 0 - 50 wppm other oxygenates 0 - 500 wppm Fischer-Tropsch derivative materials usually contain few unsaturates, for example < 1% by weight of olevins and aromatics, preferably less than about 0.5% by weight of total aromatics, and no sulfur and nitrogen, ie less than about 50 ppm by weight of sulfur or nitrogen. Hydrotreated Fischer-Tropsch liquids containing virtually zero or only trace amounts of oxygenates, olefins and aromatics, sulfur and nitrogen can also be employed. Nonionic surfactant is usually used in amounts equal to or less than those required to emulsify petroleum-derived liquids. In this way, the concentration of surfactant used is sufficient to allow the formation of the relatively stable macro emulsion. Preferably, the amount of surfactant employed is at least about 0.001% by weight of the total emulsion, more preferably at least about 0.01% by weight, even more preferably about 0.05 to about 5% by weight, and more preferably 0.05 to less. of 3% by weight and in particular preferably 0.05 to less than about 3% by weight, and particularly especially 0.05 to less than about 2% by weight. Typically, useful surfactants for preparing the emulsions of this invention are nonionic and ionic and those used to prepare emulsions of bitumen or petroleum derivative materials, and are well known to those skilled in the art. These surfactants usually have an HLB of about 7-25, preferably 9-15. Surfactants useful for this invention include ethoxylated alkylphenols with 5-30 moles of ethylene oxide per molecule, ethoxylated linear alcohols, ethoxylated octylphenol, ethoxylated fatty alcohols, ethoxylated stearic acid, ethoxylates of stearyl alcohol, ethoxylated dialkyl phenol and alkyl glycosides, preferably alkyl ethoxylated phenols and most preferably nonylphenols ethoxylated with about 8-15 ethylene oxide units per molecule. A particularly preferred emulsifier is an alkyl phenoxy polyalcohol, for example nonyl phenoxy poly (ethyleneoxy ethanol), commercially available from various sources, including the trade name Igepol. The use of water-fuel emulsions significantly improves fuel characteristics and particularly with respect to materials of this invention, where Fischer-Tropsch water emulsions have better emission characteristics than petroleum-derived emulsions, ie with respect to emissions of particles and N0X. The emulsions of this invention are formed by conventional emulsion technology, that is, by subjecting a mixture of the hydrocarbons, water and surfactant to sufficient shearing, as in a commercial mixer or its equivalent for a period of time sufficient to form the emulsions, by example usually a few seconds. For information on emulsions, see in general "Colloidal Systems and Interfaces" (Systems and Colloidal Interfaces), S. Ross and I. D. Morrison, J.W. Wiley, NY.

The Fischer-Tropchs process is well known to people skilled in the art, see for example the US patents. Nos. 5,348,982 and 5,545,674 incorporated herein by reference and typically involve the reaction of hydrogen and carbon monoxide in a molar ratio of about 0.5 / 1 to 4/1, preferably 1.5 / 1 to 2.5 / 1, at temperatures of about 175-400 ° C, preferably about 180-240 ° C, at pressures of 1-100 bar, preferably about 10-50 bar, in the presence of a Fischer-Tropsch catalyst, generally a non-noble metal of Group VIII supported or unsupported, for example Fe, Ni, Ru, Co and with or without a promoter, for example ruthenium, rhenium, hafnium, zirconium, titanium. Supports, when used, can be oxides of refractory metals such as Group IVB, ie titanium oxide, zirconium oxide, or silica, alumina or silica-alumina. A preferred catalyst comprises a non-displacing catalyst, for example cobalt or ruthenium, preferably cobalt, with rhenium or zirconium as a promoter, preferably cobalt / rhenium supported on alumina, silica or titanium oxide, preferably titanium oxide. The Fischer-Tropsch liquids, ie C5 +, preferably C10 +, are recovered and light gases, for example unreacted hydrogen and CO, C? to C3 or C4 and water, they are separated from the hydrocarbons. The hydroisomerization conditions for Fischer-Tropsch hydrocarbon derivatives are well known to those skilled in the art. In general, conditions include: WIDE PREFERRED CONDITION Temperature, 149-482 ° C 288-399 ° C 300-900 ° F 550-750 ° F Total pressure, kg / cm2 man. 21.09-175.8 21.09-105.5 (psig) (300-2500) (300-1500) Hydrogen Treatment Rate, 1 / B 14,160-141,600 56,640-113,280 (SCF / B) 500-5000) (2000-4000) Consumption of hydrocarbons is a result of the conditions. The catalysts useful in hydroisomerization are typically bifunctional in nature they contain an acid function as well as a hydrogenation component. A catalytic hydropyrolysis suppressor can also be added. The hydropyrolysis suppressant can make a Group IB metal, preferably copper, in amounts of about 0.1-10% by weight of a sulfur source or both. The sulfur source can be provided by presulfurizing the catalyst by known methods, for example by treatment with hydrogen sulfide until degradation occurs. The hydrogenation component can be a Group VIII metal, whether a noble or non-noble metal. Preferred non-noble metals may include nickel, cobalt or iron, preferably nickel or cobalt, more preferably cobalt. The metal of the HIV Group is usually present in catalytically effective amounts, that is in the range of 0.1 to 20% by weight. Preferably, a Group VI metal is incorporated into the catalyst, for example molybdenum in amounts of about 1-20% by weight. The acid functionality can be provided by a support with which the metal or catalytic metals can be formulated by well-known methods. The support can be any oxide or refractory or mixtures of refractory oxides or zeolites or their mixtures. Preferred supports include silica, alumina, silica-alumina-phosphates, titanium oxide, zirconium oxide, vanadium oxide and other oxides of Groups III, IV, V or VI, as well as Y-screens, such as ultra-stable Y-screens. Preferred supports include silica-alumina wherein the silica concentration of the bulk carrier is less than about 50% by weight, preferably less than about 35% and in particular 15-30% by weight. When alumina is used as the support, small amounts of chlorine or fluorine can be incorporated into the support to provide the acid functionality. A preferred support catalyst has surface areas in the range of about 180-440 m2 / gm, preferably 230-350 m2 / gm, a gross density of about 0.5-1.0 g / ml, and a lateral cracking strength of about 0.8 at 3.5 kg / m. The preparation of the preferred amorphous silica-alumina microspheres for use in supports is described by Ryland, Lloyd B., Tamele, M., and Wilson, J. N., Cracking Catalysts, Catalysis; Volume VII, Ed. Paul H. Emmett, Reinhold Publishing Corporation, New York, 1960. During hydroisomerication, the conversion of 371 ° C (700 ° F +) to ranges of 371 ° C (700sF) of approximately -80%, preferably 30-70%, more preferably about 40-60% and essentially all the olefins and oxygenates are hydrogenated. The catalysts can be prepared by any well known method, for example impregnation with an aqueous salt, incipient wetting technique, followed by drying at about 125-150 ° C for 1-24 hours, calcined at about 300-500 ° C for about 1 hour. -6 hours, reduction by treatment with a gas containing hydrogen or hydrogen and if desired, sulfurizing by treatment with a sulfur-containing gas, for example H2S at elevated temperatures. The catalysts will then have about 0.01 to 10% by weight of sulfur. The metals can be formulated or added to the catalyst either in series, in any order or by co-impregnation of two or more metals. To exemplify this invention, several mixtures of emulsions were prepared at room temperature, although preparation temperatures may be in the range of about 10-100 ° C, preferably 15-30 ° C. The surfactant was first mixed with water and made with a Waring blender for 5 seconds. Then, the hydrocarbon is added and mixed for one (1) minute. If an emulsion is not formed, the mixing is continued in sequences of one minute (1), verifying by an emulsion after every minute. If an emulsion is not formed after a total of five (5) minutes of mixing time, the emulsification was not successful. We use the following conditions: Surfactant: Igepol CO-630 (Rhone-Poc); non-phenol ethoxylated with 9 mol of EO Proportion of water: Hydrocarbons 30/70 Amount of mixture: 200 ml Type of water: tap water Hydrocarbons: Diesel Fischer-Tropsch (boiling range 121-371 ° C (250-700 ° F)) described below and European summer grade diesel fuel derived from conventional oil. The Fischer-Tropsch diesel is prepared by converting hydrogen and carbon monoxide (H2: CO 2.11-2.16) into heavy paraffins, in a Fischer-Tropsch sludge reactor with a rhenium / cobalt catalyst supported with titanium oxide described in the patent of the USA No. 4,568,663. The reaction conditions were approximately 218 ° C (425 ° F) and 20.25 kg / cm2 gauge (288 psig) and a linear gas velocity of 17.5 cm / sec. Alfa was 0.92. The Fischer-Tropsch wax was predominantly 260 ° C (500 ° F +) hydrogenated in a fixed bed flow through unit using an amorphous silica-alumina catalyst of molybdenum and cobalt as described in US Pat. Nos. 5,292,989 and 5,378,348. The hydroisomerization conditions include 376 ° C (708 ° F), 52.73 kg / cm2 gauge (750 psig) of H2 70,800 1 / B (2500 SCF / B) H2 and a liquid hourly space velocity (LHSV) of 0.7 - 0.8. The hydroisomerization is conducted with reactor wax recycle of 371 ° C (700 ° F). The combined feed ratio (Fresh Feeding + Recycling Feeding) / Fresh Feeding was 1: 5, The product was then fractionated and a nominal cut diesel 160-371 ° C (320-700 ° F) was recovered. This product contains zero sulfur, nitrogen, aromatics, oxygen (ados) and unsaturated and is essentially 100% paraffinic. Eleven tests were prepared with Tests 1 and 11 which are 100% petroleum derived diesel and 100% Fischer-Tropsch derivative diesel respectively, which is shown in Table I below. Table 1 # Diesel Diesel Test Surfactant Derived from Fischer-Petról < so Tropsch 11 00 110000 0.3 2 25 75 0.25 3 25 75 0.3 4 40 60 0.2 5 50 50 0.15 66 5500 5500 0.1 7 60 40 0.3 8 75 25 0.35 9 75 25 0.3 10 90 10 0.3 1111 110000 00 0.75 These data are plotted and they graphically show Figure 1. From the graph, it is clear that the minimum surfactant concentration to emulsify 100% petroleum-derived diesel was 0.75% by weight, while the minimum surfactant required to emulsify 100% Fischer-Tropsch hydrocarbons was 0.3%. The Table and Figure 1 clearly show that no more than 0.3% by weight of surfactant was required to emulsify any combination of petroleum-derived hydrocarbons and Fischer-Tropsch derivatives. However, for the surfactant required to emulsify any hydrocarbon, the required amount of surfactant could be expected to emulsify any mixture of the two hydrocarbons that falls on or around the dotted line.

Claims (10)

1. CLAIMS 1. An emulsion characterized in that it comprises: - Fischer-Tropsch-derived hydrocarbon liquid, non-Fischer-Tropsch hydrocarbon liquid, water, an amount of surfactant less than or equal to the amount required to emulsify any liquid by itself. The emulsion according to claim 1, characterized in that the emulsions contain 60% by weight or less of distillates not derived from Fischer-Tropsch. 3. The emulsion according to claim 2, characterized in that it comprises 10-90% by weight of hydrocarbons. 4. The emulsion according to claim 2, characterized in that the level of surfactant is at least 0.1% by weight. 5. The emulsion according to claim 2, characterized in that the level of surfactant is approximately 0.05-3% by weight. 6. The emulsion according to claim 1, characterized in that the Fischer-Tropsch-derived liquid boils in the range of C4- 371 ° C (700 ° F). The emulsion according to claim 6, characterized in that the Fischer-Tropsch derivative liquid is a diesel fuel or diesel fuel additive. The emulsion according to claim 1, characterized in that the Fischer-Tropsch non-derivative liquid is derived from petroleum. 9. The emulsion according to claim 8, characterized in that the liquid derived from petroleum is a diesel fuel. 10. The emulsion according to claim 2, characterized in that the water is a Fischer-Tropsch process water.