Field of the Invention

This invention relates to fuel compositions and their combustion primarily for industrial purposes. More particularly, the fuel compositions contain used or reprocessed oils blended with other hydrocarbon-containing fractions, and their combustion produces low sulfur and/or low nitrogen emissions.

Background Used oils, particularly those employed as lubricating oils, are normally considered waste once they have been used for their intended purpose (e.g., crankcase oils, etc.) as lubricants and are normally disposed by either being burned (combusted) or discarded. The latter disposal method has deleterious environmental ramifications for ground water quality. However, such discarded used oils may be recycled

(i.e., reprocessed) to produce useable petroleum products, including both fuel products and re-refined lubricating oils.

Large industrial burners often burn low-cost, low ash- containing bunker fuels, whose high sulfur (1-2 weight percent) and nitrogen (3,000-6,000 ppmw) concentrations lead to unacceptably high emissions of SO _x and N0 _X . Furthermore, bunker fuels normally are relatively heavy (API gravities of about 12 or lower) , and require heated storage and relatively high injection temperatures.

In spite of these problems, bunker fuel oils have been the fuel of choice as a low-cost fuel for industrial burner applications, in part, due to their low ash content. Table 1 summarizes several of the typical properties of three exemplary conventional bunker fuels.

Table l

PROPERTIES OF BUNKER FUEL OILS

IFO 280 PS-400 MFO

Gravity, API 11.9 7.0 12.0

Specific Gravity, 0.9868 1.022 0.9863

60° F

Flash Point,

PMCC, °F 180 150 min 196

Higher Heating Value

Btu/lb 18,400 18, ,086 18,400

Btu/gal 151,400 153, ,900 151,100

MM Btu/bbl 6.36 6. .46 6.35

Pour Point, °F +20 +30 +25

Viscosities, cSt

104° F 556.1 831.3

122° F 281 80-120

212° F 27.72 32.63

225° F 22.0

Viscosities, SUS

237° F 90.0

246° F - 90.0

Sulfur, wt% 1.30 1.75 max 1.94

Chlorine, ppm 136 180

Nitrogen, ppm - 2500-6000 3800

Carbon Residue,

D524, wt% - 10.3

Metals, ppm

Aluminum 15 1.5-7.0

Arsenic <2

Chromium <2 0 .1-0.5

Copper 5 0 .2-5

Iron 23 5-30

Nickel 52 10-25 24.6

Potassium 31

Silicon 14 2.5-20

Vanadium 84 35-100 56.8

Ash, wt% 0.046 0 .03-0.07

The used oils are commonly used as fuels in space heaters and industrial burners. However, the environmental benefits and consequences of the combustion of used oils in industrial furnaces have been extensively debated over the past years. Used or waste oil combustion is presently regulated and the allowable levels of contaminants contained in the waste oil compositions have recently been established. For instance, the sulfur level in used oil contemplated for reuse for burning is limited in many areas to less than 0.5 weight percent. In spite of such regulation, it is contemplated by the present invention to more effectively and more economically utilize the used or reprocessed oils in place of bunker fuels in industrial applications.

g-utnm--»-ry nf the Invention According to one aspect of the invention, there is provided a fuel composition having a sulfur concentration less than about 0.5 weight percent, calculated as S, comprising: a reprocessed fuel oil; and a blending component having essentially all its hydrocarbon components boiling above about 150° F. , a flash point above about 150° F. and a sulfur concentration less than about 0.5 weight percent, calculated as S.

According to another aspect of the invention, there is provided a process for burning a fuel blend composition in a furnace, the process comprising: introducing a fuel blend composition having a sulfur concentration less than 0.5 weight percent, calculated as S, and an ash content less than 0.5 weight percent, measured by X-Ray diffraction, into a combustion zone of a furnace capable of burning wood and/or the fuel blend composition, the fuel blend composition comprising a reprocessed fuel oil and a blending component having essentially all its hydrocarbon components boiling above about 150° F. , a flash point above about 150° F. and a sulfur concentration less than about 0.5 weight percent, calculated as S; and combusting the fuel blend composition.

In accordance with the present invention, it has been discovered that a fuel blend composition prepared from used or reprocessed fuel oil combined with a blending component having

essentially all its hydrocarbon components boiling above about 150° F. , a flash point above about 150° F. and a sulfur concentration less than about 0.5 weight percent, calculated as elemental sulfur (S) , can be used in place of conventional bunker fuels in various types of industrial burners. The blending component normally has an ash content less than that of the reprocessed fuel oil, and therefore the ash content of the resultant fuel blend is lower than that of the reprocessed fuel oil. Furthermore, the fuel blend contains a reduced sulfur concentration relative to the used or reprocessed oil or to conventional bunker fuels, and still provides competitive heating values and low ash contents at substantially reduced costs. Typical examples of blending components include low sulfur fuel oil, diesel fuel and Jet A fuel. The fuel blend composition of the invention can be utilized in essentially all processes involving combustion in an oxygen-containing atmosphere; however, it is preferred to burn the novel fuel blend in an industrial burner application, such as in waste oil furnaces, space heaters, steam boilers, package boilers, calciners, and particularly, hog fuel (wood scrap)- fired boilers having ash-handling capability.

Advantages of the fuel blend of the invention over bunker fuels are its relatively low viscosity (i.e., less than about 150 cSt at 122° F.) and high API gravity (i.e., above 15), which normally allows it to be stored without heating. Furthermore, the fuel blend is environmentally safe, containing less than 0.5 weight percent sulfur, and can be injected into the burners at relatively low temperatures, i.e., it has a suitable viscosity for injection at a temperature of about 200° F.

Detailed Description of the Invention

The present invention provides a fuel blend for use primarily in industrial burner applications. An essential ingredient of the fuel blend is a reprocessed fuel oil (known herein as RFO) . An RFO is defined herein as a used lubricating oil from which water, sludge and light ends (hydrocarbons boiling at less than 200° F. , including fuel fraction light hydrocarbons, and the like) have been removed. As used herein,

"used lubricating oil" refers to discarded oil capable of being burned directly or after removal of at least some contaminants. Typically, the used lubricating oil is capable of being recycled to reuseable fuel products, including both reclaimed products and re-refined. The used lubricating oil normally comprises discarded engine or industrial oils, but can include minor quantities of other specialty oils, e.g., synthetic oils, or white oils, etc., and mixtures thereof.

Removal of water, fuel fraction light hydrocarbons and light vacuum gas oil from used oils is a procedure well-known in the refining or re-refining industry. Such dewatering and light ends removal is preferably performed by atmospheric and/or vacuum distillation, although other procedures such as settling, centrifuging, treatment with chemical drying agents, selective adsorbents or extractants can also be employed. Optionally, the used oil can be passed through a centrifuge, shaker, filter or other separation means to reduce the level of sludge, including entrained solids (i.e., dirt, metal filings, sand, etc.) which may be present in the used oil so as to reduce the potential for damage to processing equipment and therefore eventually produce a higher quality RFO.

The RFO utilized in the invention typically has a water content less than 1.5 weight percent and an ash content greater than 0.5 weight percent. The flash point of the RFO is above 150° F. and normally above 160° F. , for safe transportation of the RFO. Also, the RFO has contaminant levels for chlorine below 1,000 ppmw, for PCBs below 5 ppmw, for arsenic below 5 ppmw, for cadmium below 2 ppmw, for chromium below 10 ppmw, and for lead below 100 ppmw. Ordinarily, the sulfur concentration of the RFO is less than 0.5 weight percent, calculated as S, and the nitrogen concentration is less than about 1,500 ppmw, calculated as N. Such low sulfur and nitrogen contents are considerably lower than those contained in conventional bunker fuels. In general, the API gravity of the RFO is above 20 and usually above 25, while the pour point is less than 10° F. , preferably less than 0° F. , and more preferably less than -10° F. The viscosity of the RFO at 104° F. is usually less than 300 cSt, preferably less than 100 cSt, and more preferably less than

80 cSt. Typically, the Higher Heating Value of the RFO is at least 140,000 Btu/gal. Representative properties of an RFO which can be utilized in the invention are found in Table 2 in Example 1 below, which table is offered merely as an illustration and not by way of limitation.

The RFO is mixed with a blending component to produce a fuel blend composition of the invention. The blending component normally has burnable hydrocarbon-containing components, essentially all of which boil above about 150° F. and often above about 250° F. Furthermore, the blending component has less than about 0.5 weight percent of sulfur components, calculated as S, and less sulfur than that contained in the RFO. Moreover, the blending component has less ash content than the RFO, and normally contains an ash content less than 0.5 weight percent, preferably less than 0.25 weight percent, and most preferably less than 0.1 weight percent, measured typically by X-Ray diffraction techniques.

With respect to other properties of the blending component, the flash point is usually above 150° F. , often above 160° F. , and even above 190° F. in some cases. The API gravity of the blending component is at least about 10, the specific gravity must be no more than 1.00, and the SFS viscosity at 122° F. is normally in the range from about 25 to about 250, particularly in the case of a low sulfur fuel oil blending component. The water content of the blending component is no more than about 1.0 weight or volume percent, usually less than 0.75, and preferably less than 0.5 weight or volume percent.

Examples of blending components include low sulfur fuel oils (e.g., those containing less than 0.5 weight percent sulfur) , diesel fuel, and Jet A fuel, with the low sulfur fuel oils being preferred. Typical low-sulfur fuel oils, useful as a blending component, are obtained as an extract from the solvent extraction/deasphaltene processing of a residuum distillate feedstock or as a product of hydrotreating, and may be blended with a kerosine cutter stock up to about 30 weight percent of the total blending component. Representative properties of a low sulfur fuel oil blending component which can be utilized in the invention are found in Table 3 in Example 1

below, which table is offered merely as an illustration and not by way of limitation.

The fuel blend composition of the invention is prepared for use by means well-known in the industry. In one embodiment, separate storage of the RFO and the blending component is employed prior to their simultaneous combustion. Preferably, the RFO and the blending component are mixed and stored prior to use, with the mixed fuel blend being fed (usually by atomized injection) as needed into the combustion means (e.g., burner, furnace, etc.) in the presence of a free oxygen-containing atmosphere.

One property of the fuel blend composition of the invention, which provides effective combustion applications relative to environmental emission standards at a relatively low cost, is its combined content of at least 25 weight percent RFO and less than 0.5 weight percent sulfur components, calculated as S. The fuel blend has a lower sulfur concentration than the RFO and a substantially lower sulfur concentration than that of conventional bunker fuels. The RFO usually comprises at least 30 weight percent, but preferably from about 35 to about 75 weight percent, and more preferably from about 40 to about 70 weight percent of the fuel blend composition. The fuel blend generally contains more than 5 or more than 10 weight percent of at least one blending component, and usually contains one or more blending components in the range from about 25 to about 65, and preferably about 30 to about 60 weight percent. Furthermore, the fuel blend composition normally contains less than 3,500 ppmw, and preferably less than 3,000 ppmw of nitrogen components, calculated as N. Another feature of the invention is the reduced ash content of the fuel blend compared to the RFO. Although the ash content of the fuel blend can be any amount less than that of the RFO, normally the ash content of the fuel blend is less than 0.5 weight percent, and preferably less than 0.4 weight percent. In some instances, the ash content of the fuel blend is even less than 0.3 weight percent.

The fuel blends of the invention generally have a total lead content less than 100 ppmw, preferably less than 50 ppmw, and most preferably less than about 30 ppmw, calculated as

Pb. Normally, commercially salable fuel blends must contain less than 5 ppmw of PCBs, less than 5 ppmw of As, less than 2 ppmw of Cd, less than 10 ppmw of Cr, and less than 1,000 ppmw of Cl. Representative properties of a fuel blend composition which can be utilized in the invention, are found in Table 4 in Example 1 below, which table is offered merely as an illustration and not by way of limitation.

At ordinary temperature and pressure conditions (i.e. , RTP) , the fuel blend composition of the invention normally has usually good fluidity and is readily pumpable during the colder portions of the year. The API gravity of the fuel blend is between that of the RFO and that of the blending component, and normally greater than 15, and preferably greater than 20. The viscosity of the fuel blend at 122° F. is less than 200 cSt, preferably less than 150 cSt, and most preferably less than 125 cSt; at 175° F. , the viscosity is less than 25 cSt (the SFS viscosity being less than 50); at 212° F. , the viscosity is less than 20 cSt; and the SUS viscosity is about 90 at less than 225° F., preferably at less than 210° F. and most preferably at less than 200° F. The pour point of the fuel blend is typically less than 10, preferably less than 0, and most preferably less than - 10° F. Representative viscosity properties of a fuel blend composition which can be utilized in the invention are found in Table 5 in Example 2 below ^" in a comparison to a typical bunker fuel, which table is offered merely as an illustration and not by way of limitation.

The fuel blend composition of the invention has a flash point above about 100° F., and usually greater than about 150 or 160° F. so as to be suitable for safe transportation of the blend. The fuel blend is usually supplied to combustion means and, for injection purposes, the flash point is usually less than 230° F. , and sometimes less than 200° F. The Higher Heating Value of the fuel blend is usually above 140,000 Btu/gal, and preferably greater than 145,000 Btu/gal. In contrast to the pre-heating of conventional bunker fuels, the fuel blend of the invention is normally not pre¬ heated to as high a temperature prior to being injected into a combustion zone. Typically, the fuel blend of the invention is preheated to less than about 225° F., preferably less than 210°

F., and most preferably to 205° F. or less. Pre-heating can even be eliminated in some cases. The fuel blend is normally atomized in the presence of oxygen (typically air) and ignited in the combustion zone at a temperature greater than about 160° F. to produce the desired energy as well as less SO,, NO _x and ash combustion products than from combustion of the RFO alone. In any event, the ash content of the fuel blend is lower than that of the RFO.

Although any combustion operation may utilize the fuel blend of the invention, industrial burner or furnace applications requiring a suitable heating value are preferred. Preferred combustion means for the inventive fuel blends include waste oil furnaces, steam boilers, package boilers, space heaters, calciners, and more preferably, wood-burning furnaces, such as hog fuel boilers capable of burning wood and/or hydrocarbon-containing fuels. Normally such wood- burning furnaces are constructed with auxiliary injection means for injecting hydrocarbon-containing fuels, such as those of the present invention, into a combustion zone. Typical boilers are those found in the paper making industry. The invention is further described by the following examples which are illustrative of a specific mode of practicing the invention and are not intended as limiting the scope of the invention as defined by the appended claims.

Example I

A relatively low-cost RFO and a representative low- cost blending component (e.g., an LSFO) are blended to produce a relatively low-cost fuel blend composition of the invention.

Equal volume proportions of the RFO and the LSFO are mixed together in a tank to produce the fuel blend composition.

The respective properties of the RFO are summarized in Table 2, the properties of the LSFO are summarized in Table 3 and the properties of the 50 weight percent RFO/50 weight

percent LSFO fuel blend of the invention are summarized in Table 4 below.

Table 2

PROPERTIES OF REPROCESSED FUEL OIL (RFO) ¹

RFO Detection Max. or Min

Tvoical Limit Spec.

Gravity, "API 27.5

Specific Gravity,

60° F 0.8897

Flash Point, PMCC, °F 250 160 min

Higher Heating Value

Btu/lb 19,200

Btu/gal 143,000

MM Btu/bbl 6.03

Pour Point, °F -25

Viscosities, cSt

104° F 63.79

212° F 9.579

Viscosities, SUS

168° F 90.0

Sulfur, wt% 0.43

Nitrogen, ppm 1055

Chlorine, ppm 260 1000 max

Phosphorous, ppm 837

PCBs, ppm <1 5 max

Metals, ppm

Aluminum 8.9

Arsenic <0.1 1 5 max

Barium <0.5 0.5

Cadmium <0.5 0.5 2 max

Calcium 1020

Chromium 1.5 0.5 10 max

Copper 33

Iron 101

Lead 10-50 0.5 100 max

Mercury 0.53 0.2

Nickel 0.9

Potassium 32

Selenium <5

Silicon 30

Silver <5

Sodium 112

Vanadium 0.3

Zinc 710

Ash, wt% 0.58

¹ RFO is used lubricating oil with water, light ends and sludge removed.

Table 3

PROPERTIES OF LOW SULFUR FUEL OIL (LSFO)

LSFO Max. or Min

Typical Soec.

Gravity, API 13.1 10 min

Specific Gravity, 60° F 0.979 1.00 max

Flash Point, PMCC , °F 192 150 min

Higher Heating Value

Btu/lb 18,470

Btu/gal 151,670

MM Btu/bbl 6.42

Pour Point, °F 30,48

Viscosities, cSt

122° F 432

210° F 38.2

Viscosity, SUS

245° F 90.2

253° F 90.3

Viscosity, SFS, 122° F 200-225 35-225

Sulfur, wt% 0.34 0.5 max

Nitrogen, ppm 3000

Metals, ppm

Aluminum 6

Silicon 10

Sodium 3

Vanadium 4

Ash, wt% 0.007

Compatibility, D- 4740, spot# 1/1

Water, vol% 0.05 1.0 max

Conradson Carbon, Wt% 14.0

Asphaltenes, wt% 5.8

Table 4

PROPERTIES OF RFO:LSFO BLEND

50 wt% RFO/ 50 wt% LSFO

Gravity, API 20.7 Specific Gravity, 60° F 0.9297 Flash Point, PMCC, °F 230 Higher Heating Value

Btu/lb 18,791

Btu/gal 145,500

MM Btu/bbl 6.11 Pour Point, °F -11 Viscosities, cSt

122° F 112

212° F 16.1 Viscosity, SFS, 122° F 42.3 Viscosity, SUS, 205° F 90.1 Sulfur, wt% 0.4 Nitrogen, ppm 2000 Chlorine, ppm 105 Phosphorus, ppm 415 Metals, ppm

Vanadium 4.0

Lead 5-25

Chromium 0.75

Zinc 355

Calcium 510

Potassium 16 Ash, wt% 0.44 Sediment, vol% 0.1 Water, vol% 0.55

As indicated in Table 4, the sulfur concentration of the fuel blend is decreased more than three (3) fold compared to that of the hereinbefore disclosed representative bunker fuels as shown in Table 1, and is also lower than the RFO. The Higher Heating Values of the inventive fuel blend are above 145,000 Btu/gal and the ash weight percentage is only 0.44, both values being improvements over the RFO. Also, the nitrogen concentration is only 2000 ppmw. Also, the flash point of the fuel blend is 230° F. whereas that of the bunker fuels is typically below 200° F.

In terms of fluidity, the pour point of the fuel blend is -11° F. , which is more than 20 (and even more than 30 or 40° F.) units less than the pour points of typical bunker fuels. A suitable SUS viscosity for fuels atomized and injected in typical combustion means (hog fuel burners, etc.) is usually in the range from about 85-95, and preferably about 90. The SUS viscosity of the above inventive fuel blend is about 90 at only 205° F. whereas the typical bunker fuels have an SUS viscosity of about 90 at much higher temperatures, i.e., 237 and 246° F.

Example II

The viscosity of the fuel blend composition of the invention obtained above in Example 1 is compared to exemplary bunker fuel IFO 280 disclosed hereinbefore in Table 1. The viscosity values at selected temperature for the inventive fuel blend and the bunker fuel are summarized in Table 5 below.

Table 5

VISCOSITIES OF INDUSTRIAL FUELS Viscosities. cSt

50% RFO/ Bunker

Temp.. F. 50% LSFO IFO-280

30 6300 38000

40 3400 18000

60 1200 4900

80 482 1600

110000 222266 653

120 119 301

140 68.4 155

160 20.3 87.9

180 - 53.4

The data in Table 5 indicate that the fuel blend of the invention is substantially less viscous at corresponding temperature conditions than a typical bunker fuel. Accordingly, the fuel blends of the invention usually do not require heated storage tanks during the colder months, particularly when the RFO comprises at least 35, and preferably at least 40 weight percent of the fuel blend.

EXAMPLE III

A fuel blend composition of the invention is formulated by mixing 40 weight percent of the RFO described in Example 1 with 40 weight percent of the LSFO described in

Example 1 and 20 weight percent of a Jet A fuel having the properties summarized below in Table 6. A second fuel blend of the invention is formulated with 12 weight percent of the Jet A fuel with equal portions (44 weight percent each) of the RFO and LSFO.

In addition to the properties for the Jet A fuel, the properties of the two inventive fuel blends are summarized in Table 6 below.

Table 6

PROPERTIES OF RFO, LSFO AND JET A BLENDS

Jet A 20.0% Jet A/40% 12% Jet A/44%

Fuel RFO/40% LSFO RFO/44% LSFO

Gravity, API 40.5 24.3 22.5

Spec. Gravity,

60° F 0.8227 0.9083 0.9190

Flash Point,

PMCC, °F 135 >160 >160

Higher Heating

Value

Btu/lb 19,780 18,974 18,860

Btu/gal 135,490 143,500 144,300

MM Btu/bbl 5.69 6.03 6.06

Viscosities, cSt

104° F 1.532 41.91 73.89

175° F 0.941 10.78 16.00

Viscosities, SUS

(143° F) - 90.3 -

(167° F) - - 90.3

Sulfur, wt% 0.00 0.32 0.36

Nitrogen, wt% 0.00 0.23 0.25

Phosphorous, ppm - 290 360

Metals, ppm

Cadmium - 0.2 0.3

Calcium - 350 445

Lead - 20 25

Potassium - 11 14

Sodium - 41 52

Zinc - 246 310

Ash, wt% - 0.3 0.4

The data in Table 6 indicate that lower sulfur concentrations of the inventive fuel blend can be obtained with a low sulfur-containing blending component (i.e., Jet A fuel and LSFO) and that a relatively high heating value (Higher Heating) can still be achieved in the presence of at least 40 weight percent of the RFO. The sulfur content of the Jet A/LSFO/RFO fuel blends is slightly decreased (0.36 wt. % and 0.32 wt. %) relative to the RFO (0.43 wt. %) and an improved Higher Heating Value is achieved (144,300 Btu/gal and 143,500 Btu/gal vs. 143,000 Btu/gal). Furthermore, the fuel blends have excellent

fluidity—having SUS viscosities of about 90 at only 143 and 167° F. , respectively.

EXAMPLE IV

The RFO described in Example 1 is blended with an EPA diesel fuel and the LSFO described in Example 1 to produce two fuel blend compositions of the invention. In one blend, equal weight proportions of the RFO, LSFO and diesel are mixed, while the second blend is prepared by mixing 13.6 weight percent of the diesel fuel with equal weight percentages of RFO and LSFO (i.e., 43.2 weight percent each).

The respective properties of the EPA diesel and the two inventive fuel blends are summarized in Table 7 below.

Table 7

PROPERTIES OF RFO, LSFO AND EPA DIESEL BLENDS

EPA 33. .0% Diesel/33, .5% 13 . 6 %

Diesel/43.2%

Diesel RFO/33.5% LSFO RPO/43.2%

LSFO

Gravity, API 34.0 24.8 22.4

Spec. Gravity,

60° F 0.8550 0.9051 0.9195

Flash Point,

PMCC, °F 160 >160 >160

Higher Heating Value

Btu/lb 19,200 19,070 18,940

Btu/gal 136,700 142,600 144,300

MM Btu/bbl 5.74 5.99 6.06

Viscosities, cSt

122° F 2.17 19.36 50.43

210° F 1.105 5.191 9.841

Viscosities, SUS

125° F - 90.6 —

171° F - - 90.6

Sulfur, wt% 0.05 0.29 0.36

Nitrogen, ppm 400 1500 1800

Phosphorous, ppm - 290 360

Metals, ppm

Cadmium - 0.2 0.3

Calcium - 350 445

Lead - 20 25

Potassium - 11 14

Sodium - 41 52

Zinc - 246 310

Ash, wt% - 0.3 0.4

The data in Table 7 indicate that fuel blends containing at least 10 weight percent of diesel in combination with at least 30 weight percent of RFO and 30 weight percent of LSFO have substantial heating values, i.e., 142,600 and 144,300 BTU/gal. and low viscosity, i.e., SUS viscosities of about 90 at 125° F. and at 171° F. , respectively. Such fuel blends contain relatively low sulfur concentrations, i.e., 0.29 and 0.36 weight percent (as S) , respectively, relatively low nitrogen concentrations, i.e., 1,500 and 1,800 ppmw (as N) , respectively, and sufficient flash points (greater than 160° F.).

EXAMPLE V

A fuel blend of the invention is formulated by mixing the EPA diesel fuel described in Example IV with the RFO described in Example 1 in a weight percentage ratio of 57.8 to 42.2, respectively. The properties of such a fuel blend are summarized in Table 8 below.

Table β

PROPERTIES OF RFO:

EPA DIESEL BLEND

EPA 57. .8% Diesel/

Diesel 42, .2% RFO

Gravity, API 34.0 31.2

Spec. Gravity, 60° F 0.8550 0.8696

Flash Point, PMCC, °F 160 >160

Higher Heating Value

Btu/lb 19,200 19,330

Btu/gal 136,700 140,000

MM Btu/bbl 5.74 5.88

Viscosities, cSt

122° F 2.17 6.122

210° F 1.105 2.422

Viscosities, SUS

60° F - 90.0

Sulfur, wt% 0.05 0.09

Nitrogen, ppm 400 680

Phosphorous, ppm - 360

Metals, ppm

Cadmium - 0.3

Calcium - 440

Lead - 6-30

Potassium - 14

Sodium - 48

Zinc - 3.7

Ash, wt% 0.25

The data in Table 8 indicate that a relatively high weight proportion of the diesel blending component combined with at least 35, and preferably 40 weight percent of the RFO produces a fuel blend composition containing an extremely low

concentration of sulfur (i.e., 0.09 weight percent S) and nitrogen (i.e., 680 ppmw N) , still has a heating value of at least 140,000 BTU/gal., and has excellent fluidity—an SUS viscosity of about 90 at only 60° F. While the preferred embodiment of the invention has been shown and described, and some alternative embodiments and examples also shown and/or described, changes and modifications may be made thereto without departing from the invention. Accordingly, it is intended to embrace within the invention all such changes, modifications and alternative embodiments as fall within the spirit and scope of the appended claims.