BLENDED FUEL COMPOSITION HAVING IMPROVED COLD FLOW PROPERTIES

Info

Publication number: 20110126449
Type: Application
Filed: Oct 29, 2010
Publication Date: Jun 2, 2011
Applicant: CONOCOPHILLIPS COMPANY (Houston, TX)
Inventors: Xiaochun XU (Bartlesville, OK), Yun BAO (Bartlesville, OK), Jianhua Yao (Bartlesville, OK), Dhananjay B. Ghonasgi (Bartlesville, OK), Edward L. SUGHRUE, II (Bartlesville, OK), Lisa L. MYERS (Bartlesville, OK)
Application Number: 12/915,502

Abstract

There is provided a fuel composition comprising petroleum based component and a renewable based component, wherein at least 20% of the compounds in said petroleum based component having boiling point range equal or greater than the boiling point of said renewable based component.

Description

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional application which claims benefit under 35 USC §119(e) to U.S. Provisional Application Ser. No. 61/265,076 filed Nov. 30, 2009, entitled “A BLENDED FUEL COMPOSITION HAVING IMPROVED COLD FLOW PROPERTIES” which is incorporated herein in their entirety.

STATEMENT OF FEDERALLY SPONSORED RESEARCH

None

FIELD OF THE DISCLOSURE

The present invention relates generally to fuel compositions. More specifically, the present invention relates to a blended fuel composition comprising petroleum based fuel and renewable fuel which exhibit improved cold flow properties. The present invention also relates to the method of making such compositions.

BACKGROUND OF THE DISCLOSURE

There is a national interest in the discovery of alternative sources of fuels and chemicals, other than from petroleum resources. As the public discussion concerning the availability of petroleum resources and the need for alternative sources continues, government mandates will require fuel range hydrocarbons to include, at least in part, hydrocarbons derived from sources besides petroleum. As such, there is a need to develop alternative sources for hydrocarbons useful for producing fuels and chemicals.

One possible alternative source of hydrocarbons for producing fuels and chemicals is the natural carbon found in plants and animals, such as for example, oils and fats. These so-called “natural” carbon resources (or renewable hydrocarbons) are widely available, and remain a target alternative source for the production of hydrocarbons. For example, it is known that oils and fats have been successfully hydrotreated to produce hydrocarbons/fuel range hydrocarbons which is also called “Renewable fuel” such as renewable diesel fuels.

Renewable diesel fuels are gaining greater market acceptance as a cutter stock to extend petroleum diesel market capacity. The blends of renewable diesel fuels with petroleum diesel are being used as fuel for diesel engines, utilized for heating, power generation, and for locomotion with ships, boats, as well as motor vehicles.

It is know to those skilled in the art that the renewable diesel may be prepared by reacting vegetable oils and/or animal fats with a hydrogenation and deoxygenation catalyst at the hydrogenation and deoxygenation conditions.

The main components in renewable diesel are n-C15 to n-C18 paraffins. Therefore, renewable diesel exhibits poor cold flow properties, e.g., cloud point, pour point and Cold Filter Plugging Point (CFPP). Generally, it is thought that renewable diesel would have a big impact on the cold flow properties of petroleum diesel, which would limit its blending concentration in the diesel pool.

The cold flow properties of renewable diesel can be improved by using dewaxing technology, either cracking or isomerization, to lower the cold flow properties, thereby minimizing the impact of renewable diesel on the cold flow properties of petroleum diesel. However, such processes will increase the production cost and decrease the diesel volume yield.

In addition, the cold flow properties of renewable diesel can also be improved by adding cold flow additives. However, cold flow additives are expensive. With the implementation of renewable diesel, the use of cold flow additives is expected to increase. Therefore, using cold flow additive is economically unfavorable.

As such, development of a blended fuel composition having improved cold flow properties without the above economic concerns would be a significant contribution to the art and to the economy.

BRIEF DESCRIPTION OF THE DISCLOSURE

The present invention relates generally to fuel compositions. More specifically, the present invention relates to a blended fuel composition comprising petroleum based fuel and renewable based fuel which exhibit improved cold flow properties.

In one embodiment of the present invention, there is provided a composition comprising a petroleum based component and a renewable based component, wherein at least 20% of the compounds in the petroleum based component having boiling point range equal or greater than the boiling point of the renewable based component. The amount of the renewable based component is in the range between 0.1 vol. % to 50 vol. %, based on the total volume of the fuel composition.

The renewable based component comprises hydrocarbons that are derived from natural, replenishable feed stock which can be utilized as source of energy.

The petroleum based component comprises hydrocarbons derived from petroleum refining process. The petroleum based component can be a diesel base fuel having boiling points within the range of 150° C. to 400° C.

In one embodiment of the present invention, a method is provided for preparing a fuel composition comprising blending a petroleum based fuel and a renewable based fuel, wherein at least 20% of the compounds in the petroleum based component having boiling point range equal or greater than the boiling point of the renewable based component.

It is discovered in this invention that the impact of renewable fuel on the cold flow properties of petroleum fuel depends on the boiling point range of the petroleum based fuel. This invention enables the refinery to minimize the use of cold flow additives when they implement renewable diesel technology.

Other objects, advantages and embodiments of the invention will be apparent from the following detailed description of the invention and the appended claims.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention relates generally to fuel compositions. More specifically, the present invention relates to a blended fuel composition comprising petroleum based fuel and renewable based fuel which exhibit improved cold flow properties. The present invention also relates to the method of making such compositions.

According to one embodiment of the current invention, there is provided a fuel composition comprising petroleum based component and a renewable based component, wherein at least 20% of the compounds in said petroleum based component having boiling point range equal or greater than the boiling point of said renewable based component.

According to yet another embodiment of the present invention, there is provided a process for preparing a fuel composition comprising blending a petroleum based fuel and a renewable based fuel, wherein at least 20% of the compounds in the petroleum based component having boiling point range equal or greater than the boiling point of the renewable based component.

According to the various embodiment of the present invention, the petroleum based component is a hydrocarbon derived from petroleum refining process. Petroleum based fuel refers to a fuel that includes a fractional distillate of petroleum. The distillate fuel in many cases can be described as a gasoline or middle distillate fuel oil.

The middle distillate fuels typically are divided into several types fuels including: jet or turbine fuels, automotive diesel fuels, railroad diesel fuels, and heating oils. These products are blended from a variety of refinery streams to meet the desired specifications. Other examples of middle distillate fuel may include industrial gas oils, distillate marine fuels, kerosene fuels such as aviation fuels or heating kerosene, light and heavy cycle oils as obtained in a fluid catalytic cracking unit, a Fisher-Tropsch derived fuel, in particular a Fischer-Tropsch derived diesel fuel.

Petroleum derived gas oil may be obtained from refining and optionally hydroprocessing crude petroleum source. It may be a single gas oil stream obtained from such a refinery process or a blend of several gas oil fractions obtained in the refinery process via different processing routes. Examples of such gas oil fractions are straight run gas oil, atmospheric gas oil, vacuum gas oil, gas oil as obtained in a thermal cracking process, and gas oil as obtained from a hydrocracker unit.

The fuel composition to which the present invention is preferably to use is for an internal combustion engine, for example a diesel fuel composition which is used in an automotive diesel engine. Therefore, the petroleum based component may be any known diesel base fuel, and it may itself comprise a mixture of diesel fuel components. It may have a sulfur content of 0 to 20,000 ppmw (parts per million by weight). It may also have a sulfur content of 0 to 15 ppmw.

Typical diesel fuel components comprise liquid hydrocarbon middle distillate fuel oils, for instance petroleum jet or turbine fuels, automotive diesel fuels, railroad diesel fuels, heating oils and gas oil They will typically have boiling points within the usual diesel range of 150° C. to 400° C., depending on grade and use.

Further according to various embodiments of the present invention, a renewable based component is a hydrocarbon that is derived from natural, replenishable feed stock which can be utilized as source of energy. Suitable examples of a renewable based component include, but not limited to, bio-diesel which is a product derived from the transesterification of a material of biological origin with an alcohol or from reacting a fatty acid with an alcohol; renewable diesel which is a product derived from hydrotreating a material of biological origin; alcohol; other oxygenate; vegetable oil or vegetable oil derivatives; a biomass pyrolysis bio-oils, or any combinations thereof. The above mentioned material of biological origin can be selected from any triglyceride containing feedstock e.g. vegetable oils, vegetable fats, animal fats, fish oils, algae oil; any mixtures thereof.

Examples of alcohols used here include methanol, ethanol, and mixtures thereof, although virtually any C1-10 alcohol can be used.

Bio-diesel is commonly produced by the reaction of a material of biological origin with alcohols in the presence of a suitable catalyst. A material of biological origin is natural triglycerides derived from plant or animal sources. The reaction of natural triglycerides with an alcohol to produce a fatty acid ester and glycerin is commonly referred to as transesterification. Alternatively, bio-diesel can be produced by the reaction of a fatty acid with an alcohol to form the fatty acid ester. The fatty acid segments of triglycerides are typically composed of C10-C24 fatty acids, where the fatty acid composition can be uniform or a mixture of various chain lengths. The bio-diesel may be produced from single sourced components, or blends of multiple triglyceride containing feed stocks.

The term, “triglyceride,” is used generally to refer to any naturally occurring ester of a fatty acid and/or glycerol having the general formula CH₂(OCOR₁)CH(OCOR₂)CH₂(OCOR₃), where R₁, R₂, and R₃are the same or different, and may vary in chain length. Vegetable oils, such as for example, canola and soybean oils contain triglycerides with three fatty acid chains. Useful triglycerides in the present invention include, but are not limited to, triglycerides that may be converted to hydrocarbons when contacted under suitable reaction conditions. Examples of triglycerides useful in the present invention include, but are not limited to, vegetable oils including soybean and corn oil, peanut oil, sunflower seed oil, coconut oil, babassu oil, grape seed oil, poppy seed oil, almond oil, hazelnut oil, walnut oil, olive oil, avocado oil, sesame oil, tall oil, cottonseed oil, palm oil, rice bran oil, canola oil, cocoa butter, shea butter, butyrospermum, wheat germ oil, illipse butter, meadowfoam, seed oil, rapeseed oil, borange seed oil, linseed oil, castor oil, vernoia oil, tung oil, jojoba oil, ongokea oil, Jatropha oil, algae oil, yellow grease (for example, as those derived from used cooking oils), and animal fats, such as tallow animal fat, beef fat, and milk fat, and the like and mixtures and combinations thereof.

According to one embodiment of the present invention, a renewable based component may be a renewable diesel that is produced by hydrotreating triglyceride containing feedstock in the presence of a suitable catalyst.

Useful catalyst compositions for the hydrotreating process include any catalysts which may be effective in the conversion of triglycerides to hydrocarbons (e.g. renewable diesel) when contacted under suitable reaction conditions. Examples of suitable catalysts include hydrotreating catalysts. Examples of hydrotreating catalysts useful in one embodiment of the present invention include, but are not limited to, materials containing compounds selected from Group VI and Group VIII metals, and their oxides and sulfides. Examples of suitable support materials for the hydrogenation catalysts include, but are not limited to, silica, silica-alumina, aluminum oxide (Al₂O₃), silica-magnesia, silica-titania and acidic zeolites of natural or synthetic origin. Examples of hydrotreating catalysts include but are not limited to alumina supported cobalt-molybdenum, nickel sulfide, nickel-tungsten, cobalt-tungsten and nickel-molybdenum. Other catalysts useful in the present invention are sorbent compositions. Sorbent compositions can be used in either the fixed-bed reactor or the fluidized bed reactor embodiments.

According to one embodiment of the present invention, the reaction zone may comprise any suitable type of reactor. Exemplary reactors include fixed bed reactors and fluidized bed reactors. Generally, the reaction conditions at which the reaction zone is maintained generally include a temperature in the range of from about 260° C. to about 430° C. In another embodiment, the temperature is in the range of from about 300° C. to about 400° C. The reaction conditions at which the reaction zone is maintained generally include a pressure less than about 2000 psig, and more particularly between about 100 psig to about 750 psig. In one embodiment employing a fixed bed reactor, the pressure is maintained between about 100 psig to about 350 psig. In one embodiment employing a fluidized bed reactor, the pressure is maintained between about 400 psig to about 750 psig.

During the research and development efforts to evaluate cold flow properties of petroleum fuels, renewable fuels, and their blends, it was discovered that a combination of petroleum fuels with renewable fuels resulted in an enhancement of the cold flow properties, provided at least 20% of the compounds in the petroleum based component having boiling point range equal or greater than the boiling point of the renewable based component.

A cold flow property of fuel is a measure of the inherent handling and the use characteristics of a fuel at diminished temperature. The cold flow property of a given fuel is generally considered as the lowest temperature at which the given fuel can be utilized without causing operational difficulties. The cold flow properties of a given fuel is estimated by its cloud point (CP), pour point (PP) and its CFPP.

The CP of a fuel is the point at which first visible crystals are detected in the fuel. The PP is a standardized term for the temperature at which oil, for example, mineral oil, diesel fuel or hydraulic oil, stops flowing upon cooling. The Cold Filter Plugging Point (CFPP) of a fuel is the temperature at and below which wax in the fuel will cause severe restrictions to flow through a filter screen. CFPP is believed to correlate well with vehicle operability at lower temperatures.

The invention can be practiced at high renewable based fuel concentration, wherein the renewable based component is up to 100% by volume of the finished fuel blend. However, in the scope of the invention, the renewable based component is typically up to about 50% by volume of the finished fuel blend, more typically up to about 35% by volume of the finished fuel blend, and alternatively up to about 20% by volume of the finished fuel blend. The invention is also applicable at renewable based component concentrations as low as about 15, 10, and 5% by volume of the finished fuel blend, and even at very low renewable fuel concentrations as low as about 4, 3, 2, 1, and 0.5% by volume of the finished fuel blend.

The main components in renewable diesel are n-C15 to n-C18 paraffins. Therefore, renewable diesel exhibits poor cold flow properties, e.g., CP, PP and CFPP. Generally, it is thought that renewable diesel would have a big impact on the cold flow properties of petroleum diesel, which would limit its blending concentration in the diesel pool.

However, as illustrated in the following examples, it is surprising that when petroleum based diesel has high percentage (e.g., >20%) of compounds with boiling points higher than renewable diesel, renewable diesel has little impact on the cold flow properties of petroleum diesel. This phenomenon has been successfully demonstrated on the blended fuel composition containing up to 20% renewable based diesel. It is therefore discovered that the impact of renewable diesel on the cold flow properties of petroleum diesels depends on the boiling point range of the petroleum diesels. The higher the boiling point of petroleum diesel, the less the impact of renewable diesel on the cold flow properties. When petroleum diesel has high percentage (e.g., >20%) of compounds with boiling points higher than renewable diesel (e.g. 626° F.), renewable diesel has little impact on the cold flow properties of petroleum diesel. When petroleum diesel has high percentage (e.g., >50%) products with boiling temperatures lower than renewable diesel (e.g., 519° F.), blending renewable diesel has a big impact on the cold flow properties of petroleum diesel.

As a result of this discovery, the present invention is able to provide a more optimized method for improving the cold flow performance of a diesel fuel composition comprising renewable based component. It has now been found that by controlling the selection of the boiling point of the petroleum based diesel, the impact of the renewable based diesel on the cold flow properties of petroleum based diesels may be minimized or eliminated.

The following examples are presented to further illustrate the present invention and are not to be construed as unduly limiting the scope of this invention.

Example 1

Table 1 shows the CP, PP, CFPP and boiling point of tallow renewable diesel. For tallow renewable diesel, ˜99% of the compounds boil below 626.2° F. This is because the main components of renewable diesel are n-C 15 to n-C18 paraffins, which have boiling points between 519° F. and 602° F., respectively. CP, PP and CFPP are 60° F., 54° F. and 10° C., respectively.

TABLE 1 Cold flow Properties Tallow renewable diesel Cloud Point (F.) 60 Pour Point (F.) 54 CFPP (C.) 10 SimDis Boiling Point (F.) IBP 389.1 10% BP 521.8 50% BP 580.1 80% BP 604.6 90% BP 607.7 99% BP 626.2 FBP 643.1

Example 2

Table 2 shows the impact of renewable diesel on the cold flow properties of diesel 1. CP, PP and CFPP all increased rapidly with renewable diesel concentration. Boiling point of diesel 1 is shown in Table 3. Compared to renewable diesel, boiling point of diesel 1 is low. For example, 50% of the compounds in diesel 1 is lighter than tallow renewable diesel and less than 5% is heavier than renewable diesel. Therefore, blending renewable diesel has a big impact on cold flow properties of petroleum diesel.

TABLE 2 Impact of renewable diesel on the cold flow properties of diesel 1 Renewable Diesel Content (%) 0 2 5 10 20 Cloud Point (F.) −6 −3 1 6 17 Pour Point (F.) −21 −15 −9 −3 9 CFPP (C.) −22 −20 −18 −16 −13

TABLE 3 Boiling point of diesel 1 Boiling Point (F.) IBP 292.2 10% BP 399.2 50% BP 506.2 80% BP 570.3 90% BP 598.9 99% BP 647.5 FBP 654.1

Example 3

Table 4 shows the impact of renewable diesel on the cold flow properties of diesel 2. CP, PP and CFPP all increased with renewable diesel concentration. However, the impact of renewable diesel on the cold flow properties of diesel 2 is smaller than that of diesel 1. Boiling point of diesel 2 is shown in Table 5. Compared to renewable diesel, the boiling point of diesel 2 is still low. For example, ˜45% of the compounds in diesel 2 are lighter than tallow renewable diesel and ˜10% is heavier than renewable diesel. Therefore, blending renewable diesel still has impact on cold flow properties of petroleum diesel. However, since the boiling point of diesel 2 is higher than that of diesel 1, the impact of renewable diesel on the cold flow properties of diesel 2 is smaller than that of diesel 1.

TABLE 4 Impact of renewable diesel on the cold flow properties of diesel 2 Renewable Diesel Content (%) 0 2 5 10 20 Cloud Point (F.) 4 5 7 10 17 Pour Point (F.) −12 −9 −3 0 9 CFPP (C.) −16 −16 −16 −16 −13

TABLE 5 Boiling point of diesel 2 Boiling Point (F.) IBP 243.0 10% BP 438.7 50% BP 531.4 80% BP 602.4 90% BP 633.9 99% BP 706.6 FBP 742.8

Example 4

Table 6 shows the impact of renewable diesel on the cold flow properties of diesel 3. Renewable diesel has little impact on the cold flow properties of petroleum diesel up to 20 volume %. Boiling point of diesel 3 is shown in Table 7. There are ˜20% of the compounds in diesel 3 heavier than renewable diesel. Therefore, the heavy components in diesel 3 control the cold flow properties of the renewable diesel/petroleum diesel blends. Blending renewable diesel up to 20 volume % has little impact on the cold flow properties of petroleum diesel.

TABLE 6 Impact of renewable diesel on the cold flow properties of diesel 3 Renewable Diesel Content (%) 0 2 5 10 20 Cloud Point (F.) 25 23 23 22 25 Pour Point (F.) 15 15 12 15 18 CFPP (C.) −6 −7 −7 −7 −9

TABLE 7 Boiling point of diesel 3 Boiling Point (F.) IBP 247.1 10% BP 415.2 50% BP 537.6 80% BP 627.8 90% BP 673.7 99% BP 744.4 FBP 757.7

It is therefore discovered that the impact of renewable diesel on the cold flow properties of petroleum diesels depends on the boiling point range of the petroleum diesels. The higher the boiling point of petroleum diesel, the less the impact of renewable diesel on the cold flow properties. When petroleum diesel has high percentage (e.g., >20%) of compounds with boiling points higher than renewable diesel (e.g. 626° F.), renewable diesel has little impact on the cold flow properties of petroleum diesel. When petroleum diesel has high percentage (e.g., >50%) products with boiling temperatures lower than renewable diesel (e.g., 519° F.), blending renewable diesel has a big impact on the cold flow properties of petroleum diesel.

The results shown in the above examples, clearly demonstrate that the present invention is well adapted to carry out the objects and attain the ends and advantages mentioned as well as those inherent therein. Reasonable variations, modifications and adaptations may be made within the scope of this disclosure and the appended claims without departing from the scope of the invention. While this invention has been described in detail for the purpose of illustration, it should not be construed as limited thereby but intended to cover all changes and modifications within the spirit and scope thereof.

Claims

1. A fuel composition comprising petroleum based component and a renewable based component, wherein at least 20% of the compounds in said petroleum based component having boiling point range equal or greater than the boiling point of said renewable based component.

2. The fuel composition of claim 1, wherein the amount of said renewable based component is in the range between 0.1 vol. % to 50 vol. %, based on the total volume of the fuel composition.

3. The fuel composition of claim 1, wherein the amount of said renewable based component is in the range between 0.1 vol. % to 35 vol. %, based on the total volume of the fuel composition.

4. The fuel composition of claim 1, wherein the amount of said renewable based component is in the range between 0.1 vol. % to 20 vol. %, based on the total volume of the fuel composition.

5. The fuel composition of claim 1, wherein said renewable based component comprises isoparaffins.

6. The fuel composition of claim 1, wherein said renewable based component comprises normal paraffins.

7. The fuel composition of claim 1, wherein said renewable based component comprises hydrocarbons that are derived from natural, replenishable feed stock which can be utilized as source of energy.

8. The fuel composition of claim 1, wherein said renewable based component is selected from the group consisting of a product derived from hydrotreating a material of biological origin, a product derived from the transesterification of a material of biological origin with an alcohol, a product derived from reacting a fatty acid with an alcohol, a biomass pyrolysis bio-oils, a biologically-derived oils, alcohol; other oxygenate; vegetable oil or vegetable oil derivatives, and any combinations thereof.

9. The fuel composition of claim 8, wherein said material of biological origin is selected from the group consisting of vegetable oils, vegetable fats, animal fats, fish oils, algae oil, and any mixtures thereof.

10. The fuel composition of claim 1, wherein said renewable based component comprises a renewable diesel produced by hydrotreating triglyceride containing feedstock in the presence of a catalyst.

11. The fuel composition of claim 1, wherein said petroleum based component comprises a hydrocarbon derived from petroleum refining process.

12. The fuel composition of claim 1, wherein said petroleum based fuel comprises a fractional distillate of petroleum.

13. The composition of claim 1, wherein said petroleum based component is selected from the group consisting of a middle distillate fuel, a jet or turbine fuel, automotive diesel fuels, railroad diesel fuels, heating oils, industrial gas oils, distillate marine fuels, kerosene fuels, light and heavy cycle oils, Fischer-Tropsch fuel, and any mixture thereof.

14. The composition of claim 1, wherein said petroleum based component comprises diesel base fuel having boiling points within the range of 150° C. to 400° C.

15. A method for preparing a fuel composition comprising blending petroleum based fuel and a renewable based fuel, wherein at least 20% of the compounds in said petroleum based component having boiling point range equal or greater than the boiling point of said renewable based component.