Patent Application
20130014431
None.
This present invention relates generally to a fuel composition. More specifically, the present invention relates to a novel biomass derived low sulfur bunker fuels composition and the method of making thereof.
Bunker fuel in general refers to class of marine transportation fuels. Traditionally, these fuels were highly viscous fluids primarily composed of heavy petroleum fractions designed to burn in large, low-speed diesel engines for large shipping vessels. The bunker fuel was made up of heavy residual fuel oil (RFO) or “HFO”. In the past when refining complexity was much lower (e.g. “topping facilities”), bunker fuel was sometimes referred to as “fuel oil No. 6”, “residual”, “boiler fuel” or “Bunker C” Bunker fuels were used for both steam (boiler) powered vessels and for diesel power vessels. Because of plant efficiency (40-45%) steam plants over time were replaced by more efficient diesel engines (50%). Modern low-speed, direct drive, diesels are more efficient than medium speed engines, which require some sort of gear box or electric drive. Modern medium speed diesels are capable of burning heavier, more viscous “bunker” fuels.
Bunker fuel is mainly used directly in compression ignition, as well as, boiler combustion applications for on-board power generation in the marine and shipping industry. This traditionally heavy type of bunker fuel is used in 80% of the world's merchant fleet that utilize ocean routes. It is also used widely for stationary power and utility applications by developing nations. Historically, bunker fuel was used for boiler combustion, which produced steam. This was used in turn in turbines to power the ships propeller and in generators to produce ship's electricity. The steam was also used to heat the ship's fuel. In a diesel powered ship steam either comes from waste heat boilers (economizers) that capture the residual heat left in diesel exhaust or from auxiliary boilers fired on heavy fuel or diesel.
Modern bunker fuel can be separated into two types: marine residual fuels and marine distillates as outlined under the 2005 3rd edition of ISO 8217 standard for Class F marine fuel specification. Marine residual fuel is often referred to as intermediate fuel oil (IFO) which is generally a combination of heavy fuel oil (HFO) diluted with other lighter oil and/or distillate stocks to meet viscosity specifications.
A classic Bunker fuel composition comprises intermediate fuel oil (IFO) mixtures that are rich in HFO (No. 6) and are balanced with combinations of atmospheric distillate fuel oils (No. 1, No. 2 heating oils and diesel fuel), vacuum gas oil (VGO) and FCC light-cycle oil (LCO). The heavy fuel oil (HFO) used in Bunker fuel can also come from FCC slurry oil, heavy coker gas oil (HCGO), or other heavy petroleum fractions or intermediate refinery streams available in the event of temporary shutdowns of heavy oil processing units.
The other 20% of the bunker fuels used primarily aboard smaller vessels are marine distillates often designated as marine diesel oils (MDO) or marine gas oils (MGO). Most are simply combinations of middle distillate fuel oils mentioned above such as, AGO No. 1, No. 2, diesel No. 2 (ULSD), heating oil No. 2, LCO, LCGO and hydrocracker diesel (HCD) to be used in small engines for generating auxiliary power. Smaller watercraft such as ferries, fishing boats and some military ships use marine diesel only. These fuels are very closely related, if not the same in most cases, as non-road, locomotive, marine (NRLM) finished diesel products. The use of MDO on large vessels is fairly undefined. Most large ships have MDO in their fuel tanks for emergency diesel generators. This is because the MDO fuel does not require special heating. If some vessels operate in cold climates, special MDO fuels are blended for these extreme conditions. In the case of special equipment, such as Inert Gas Generators, MDO may be the fuel of choice, because it is more easily handled and burns cleaner with less effort. Finally, another application for MDO use is within ship incinerators.
Current Bunker fuel emission levels are projected to have significant contribution (>20%) by 2020 to the overall transportation fuel-derived emissions inventory as other industry sectors (e.g. on-road, off-road, stationary) become more compliant around the world. Further, the maritime industry was not originally included in the Kyoto protocol. Therefore, the targeted emitted species are oxides of sulfur (SOx) and greenhouse gases (i.e., CO2, CH4, and N2O) at the moment. Oxides of Nitrogen (NOx) and particulate matter (PM) are expected to take priority at a later date (>2012).
However, more attention has been given to SOx since a strong precedence has already been established with both on-road and stationary source restrictions around the globe for many years now. SOx is considered the “low-hanging fruit” of emissions policy. In 2008, global SOx emissions for registered fleets was estimated at 9 teragrams (Tg). As a result, a global cap was placed on the total amount of sulfur allowed in bunker fuel. The International Maritime Organization (IMO) recently established a North American Emission Control Area (ECA). As of Aug. 1, 2011, bunker fuel burned within 200 nautical miles of all coastlines in the U.S. and Canada must contain no more than 10,000 ppmw of sulfur. By 2015, this limit will reduce to 1000 ppmw. Outside of the ECA regions, the global cap on bunker sulfur content must remain below 35,000 ppmw by Jan. 1, 2012 and below 5000 ppmw by 2020. Currently, a commercial, market grade of low-sulfur bunker must contain less than 15,000 ppmw sulfur.
Greenhouse gas (GHG) restrictions will be much more difficult to administer and implement, however, this fact will not stop future legislation and rulings over the next few years in the U.S. and in Europe. The IMO has developed a guideline for using a greenhouse gas emission index for ships. In the U.S., residual based transportation fuel accounts for over 1% of the GHG emissions which were roughly 1,633 million metric ton for 2007. Current reports have the global shipping industry responsible for 3-5% of the global GHG emissions and nearly 15-20% by 2050.
It is highly likely that most governments around the world will impose a tax on GHG emissions from burning bunker fuel aboard ships. At some point in the future, shipping will contribute significantly to the inventory of GHG, NOx, SOx, and PM.
There is also a national interest in the discovery of alternative sources of fuels 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.
It would therefore be a significant contribution to the art and to the economy to develop a low sulfur bunker fuel composition using renewable sources such as biomass in order to meet the government fuel regulation on pollutant emissions and to reduce a potential tax obligation on GHG emissions (also known as carbon tax).
This present invention relates generally to a fuel composition and the process of making thereof. More specifically, the present invention relates to a novel biomass derived low sulfur bunker fuels composition and the method of making thereof.
Embodiment of the invention discloses a novel low sulfur bunker fuels composition derived from blending various biomass derived oils (or bio-oil)/by-products with other heavy residual fuel oils and distillates where final sulfur content is controlled by the ratio of bio-oil to other heavy residual fuel oils and distillates.
Embodiment of the invention also discloses a process of making a novel biomass derived low sulfur bunker fuels by blending various-biomass derived oils/by-products with other heavy residual fuel oils and distillates.
In one embodiment of the present invention, there is provided a blended fuel composition comprising a renewable based fuel and a petroleum based fuel. The weight ratio of the renewable based fuel to the petroleum based fuel is from 1:20 to 20:1.
In another embodiment of the present invention, a method is provided for preparing a blended fuel composition comprising blending a renewable based fuel with a petroleum based fuel in a ratio ranges from 1:20 to 20:1.
In yet another embodiment of the present invention, a blended fuel composition is provided from blending a renewable based fuel with a petroleum based fuel in a ratio ranges from 1:20 to 20:1.
The major advantage of this invention is to use a relatively inexpensive biomass to generate compounds that could be blended in current marine bunker fuels and contribute to the overall reduction of GHG emissions during ship transportation from a Life Cycle Assessment (LCA) view point. It is discovered in this invention that both the tax obligation and pollutant emissions can be reduced if the viscosity cutters and distillates are derived from a biomass source.
Therefore, the cost advantage in both price and carbon tax avoidance is unique to this novel bio-based low sulfur bunker fuel composition.
Other objects, advantages and embodiments of the invention will be apparent from the following detailed description of the invention and the appended claims.
Turning now to the detailed description of the embodiments of the present invention. It should be understood that the inventive features and concepts may be manifested in other arrangements and that the scope of the invention is not limited to the embodiments described or illustrated. The scope of the invention is intended only to be limited by the scope of the claims that follow.
In one embodiment, a renewable based fuel may comprise hydrocarbons that are derived from natural, replenishable feed stock which can be utilized as source of energy. These renewable hydrocarbons are simple in structure and may contain molecular oxygen as represented in the general formula of CxHyOz where 1<x<20, 2<Y<44, and 1<z<3 including the following organic classes; alcohols, ketones, aldehydes and acids.
According to one embodiment, a renewable based fuel comprises a bio-oil component and a bio-co-solvent component. Any oxygenated bio-oil feedstock may be used in the present invention. The bio-oil component may include but is not limited to pyrolysis oil produced by a pyrolysis process.
Pyrolysis is the chemical decomposition of biomass by heating in the absence of oxygen. U.S. Pat. No. 4,891,459, the contents of which are herein incorporated by reference in their entirety, describes one basic exemplary approach for the pyrolysis of biomass. Pyrolysis may be conducted at a variety of temperatures and pressures, with or without inert gases. Many different pyrolysis conditions are known in the art.
As used herein, pyrolysis oils may be produced by pyrolysing a material of natural, replenishable origin selected from any type of biomass including agricultural residues, city waste, and aquatic biomass. In one embodiment, pyrolysis oils may be produced by pyrolysing plant fiber, lignins, wood, wood byproducts, miscanthus, switchgrass, hemp, corn, poplar, willow, sorghum, sugarcane, tree byproducts, leaves, eucalyptus, palm, pulping liquor, paper, plant byproducts, plant oils, plant solids, grasses, agricultural byproducts, yard-waste, garbage, municipal waste, agricultural waste, biologically derived manufacturing waste, animal byproducts, animal waste, bacterial solids, algal solids, and any combinations thereof.
The composition of bio-oil is dependent upon the biomass used for pyrolysis and conditions, but bio-oil will typically include derivatives of lignins, cellulose, hemi-cellulose, fiber, starches, sugars, proteins and other components not readily soluble during typical biomass processing, milling, pulping, gasification and the like.
Bio-oils produced from biomasses are a chemically complex mixture of compounds comprising generally a mixture of water, light volatiles, and non-volatiles. As a fuel, bio-oil has a number of negative properties from a transportation fuel perspective such as thermal unstability, high acidity (corrosiveness), substantial water content (usually in the range of 15% to 30%), poor miscibility with hydrocarbon fuels, variable viscosity, low heating values (about half that of a typical diesel fuel), high oxygen content and low cetane number. These negative properties are related to the oxygenated compounds contained in bio-oils that result in a 45 wt % oxygen content. In one embodiment, raw bio-oils may be pretreated before they are blended or used as a renewable fuel. Pretreatment may include filtration, neutralization and distillation prior to admixing with said petroleum based fuel to remove a stream comprising metals, water or sediment, and to neutralize any acidic components.
In one embodiment, the pyrolysis bio-oil initially containing 30 wt % water was first partially dehydrated down to 6.4 wt % water on a rotary evaporator, then filtered overnight using Whatman #1 (11 micrometer pores) cellulosic filter paper. The filtrate was noticeably clearer afterwards. This filtered bio-oil was mixed with cyclohexane in a 1:1 volume ratio and charged to a pot flask. This mixture underwent lab-scale, batch azeotropic, vacuum distillation until almost all of the cyclohexane and moisture were removed. The weight of dehydrated bio-oil was recorded. The final water content was roughly 0.14 wt %.
According to one embodiment of the invention, the pretreated bio-oil is blended with a polar, bio-derived co-solvent (bio-co-solvent) before sending to a heated storage tank. The addition of co-solvents to the final fuel blend is optional, and the type and concentration may be dependent on the blending methodology.
In one embodiment, a bio-derived co-solvent may include common alcohol-based solvents such as, methanol, ethanol, propanol, butanol, pentanol, heptanol, octanol, nonanol, decanol, butanediol, propanediol, diethylene glycol, propylene glycol, furfuryl alcohol, glycerol, organic acids; formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, ketones; acetone, butanone, pentanone, ethyl isopropyl ketone, methyl isopropyl ketone, methyl isobutyl ketone
Further according to the various embodiments, the pretreated bio-oil/bio-derived co-solvent mixture is blended with a petroleum based fuel.
The petroleum based fuel may comprise hydrocarbons derived from petroleum refining process. These heavy petroleum fractions may include; intermediate fuel oil (IFO) mixtures that are rich in heavy RFO (No. 6) and are balanced with combinations of atmospheric distillate fuel oils (No. 1, No. 2 heating oils and diesel fuel), light vacuum gas oil (VGO), FCC light-cycle oil (LCO), hydrocracked gas oil (HCGO), light coker gas oil (LCGO), deasphalted oil (bright stock) or visbreaker gas oil (VBGO). The RFO part of IFO can be the bottoms of from the atmospheric distillation also referred to as “atmospheric reduced crude (ARC)” or the residue from vacuum distillation operations or vacuum reduced crude (VRC). If the heavy RFO isn't used directly in the IFO blend, it many undergo visbreaking or deasphalting before being used where it becomes a tar or asphalt related by-product respectively. These heavy petroleum fractions can also come from FCC slurry oil, heavy coker gas oil (HCGO) and comprise the intermediate fuel oil component disclosed in this embodiment.
In another embodiment a petroleum based fuel may include a full range of hydrocarbons derived from petroleum refining processes such as, light fuel oil, heavy residual fuel oil, atmospheric gas oil, vacuum gas oil, coker gas oils, light cycle oil, heavy cycle oil, slurry oil, hydrocracker gas oils, slop oils, unconverted gas oils, diesel fuel, heating oil, kerosene, jet fuel and various intermediate hydrocarbon streams of similar attributes
According to one embodiment petroleum residual fuel oil (RFO) may be obtained from refining and optionally hydroprocessing a crude petroleum source. It may be a single stream obtained from such a refinery process or a blend of several heavier petroleum fractions obtained by refinery processing via different processing routes.
The blended fuel composition to which the present invention is to use includes but is not limited to a marine low-speed diesel engine, for example a 380 cSt intermediate fuel oil (IFO) composition which is used in large cylinder bore (>500 mm) marine diesel engines manufactured by companies such as MAN, Wartsila and Rolls Royce. These engines are power plants capable of moving bulk carriers, large tankers and container vessels by delivering more than 50 kW. Therefore, the petroleum based component may be any known residual fuel oil (RFO), and it may itself comprise a mixture of various heavy petroleum components. It may also have a sulfur content of at least 3.5 wt %.
During the research and development efforts to evaluate various fuel properties of the petroleum fuels, renewable fuels, and their blends, it was discovered that a combination of renewable based fuel and petroleum based fuel resulted in a low sulfur fuel, provided the weight ratio of renewable based fuel to petroleum based fuel ranges from 1:20 to 20:1.
The invention can be practiced at a high renewable based fuel concentration, wherein the renewable based component is up to 100% by weight of the finished fuel blend. However, in the scope of the invention, the renewable based component is typically up to about 15% by weight of the finished fuel blend, more typically up to about 25% by weight of the finished fuel blend, and alternatively up to about 50% by weight of the finished fuel blend. The invention is also applicable at renewable based component concentrations as low as about 1, 5, and 10% by weight 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 weight of the finished fuel blend. A typical weight ratio of renewable fuel to bio-co-solvent is 2:1 and may be as high as 25:1.
Several compositions for both heavy fuel oil (HFO) and marine diesel oil (MDO) bunker fuel are given by blending various biomass derived oils/by-products with residual fuel oil and distillates.
The cost advantage in both price and carbon tax avoidance is unique to this novel bio-based low sulfur bunker fuel composition. It is discovered in this invention that both the tax obligation and pollutant emissions can be reduced if the viscosity cutters and distillates are derived from a biomass source.
The major advantage of this invention is to use a relatively inexpensive biomass to generate compounds that could be blended in current marine bunker fuels and contribute to the overall reduction of GHG emissions during ship transportation from a Life Cycle Assessment (LCA) view point.
Lifecycle GHG emissions of marine bunker fuels refer to emissions associated with the extraction and transport of crude oils, the production of bunker fuels at the refineries, the transport of bunkers fuels to the marine vessels, and the direct combustion of the bunker fuels to provide power on the marine vessels. Current U.S. regulations do not account for GHG emissions associated with the manufacturing of the marine vessels or the engines that use bunker fuels as feeds, nor do they account for the GHG emissions associated with the building of infrastructure.
Similarly, lifecycle GHG emissions for the biomass-derived fuels refer to emissions associated with the production, harvest, collection, storage, and transport of biomass to biorefineries, the conversion of biomass to a liquid transportation fuel at the biorefineries, the transport of the biomass-derived fuels to the blending terminals, the blending of the biomass-derived fuels and the marine bunker fuels into finished products, the delivery of the fuel products to the marine vessels, and the combustion of the fuels.
The biomass feedstocks may include, but are not limited to, agricultural residues, forest thinning materials, municipal solid waste (MSW), energy crops, aquatic species (such as algae), and commercially produced woody biomass (such as poplar wood). The resulting fuel products could achieve up to 80% GHG emission reduction relative to petroleum-based marine bunker fuels.
In addition, the present invention discloses that this novel fuel composition would lead to significant reduction of sulfur and/or PM (i.e., less than 1.5 wt % sulfur and 25% less ash content compared to current fuel specifications) in compliance with IMO regulation, providing a premium price advantage to the final fuel products.
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.
The examples used in this disclosure centers around bio-oil produced from the pyrolysis of woody or herbaceous biomass.
Bio-oil generated from wood or other biomass sources such as, grain fibers or hulls is sent to a pre-treatment unit to remove any metals, water, and sediment and to neutralize any acidic components. This pre-treated bio-oil is blended with a polar, bio-derived co-solvent and sent to a heated storage tank. High-sulfur (>3 wt %) residual fuel oil (RFO) is sent from a near-by refinery into another heated storage vessel. The two oils are blended to produce a low-sulfur (<1.5 wt %) advanced cellulosic bunker fuel (LSFO)
As shown in Figure Table 1, high sulfur (1.85%), commercial RMG 380 bunker fuel is used to create Blend A. The composition is a 3:1 ratio of RMG to treated bio-oil/co-solvent mixture. Neither the untreated bio-oil nor the bio-co-solvent contains sulfur. After pre-treatment with the addition of a co-solvent, Blend A qualifies as reduced carbon, low-sulfur (<1.5 wt %) blend with a minimum greenhouse gas (GHG) reduction of 6% as determined by life cycle assessment. Blend A has a lower viscosity (148 cSt), higher flashpoint (78 C) and reduced ash content (330 ppm).
In another example, straight-run high-sulfur diesel from refinery, hydrotreated pyrolysis oil and/or stand-alone renewable diesel is blended directly to produce marine diesel oil (MDO) bunker-fuel.
In closing, it should be noted that the discussion of any reference is not an admission that it is prior art to the present invention, especially any reference that may have a publication date after the priority date of this application. At the same time, each and every claim below is hereby incorporated into this detailed description or specification as an additional embodiment of the present invention.
Although the systems and processes described herein have been described in detail, it should be understood that various changes, substitutions, and alterations can be made without departing from the spirit and scope of the invention as defined by the following claims. Those skilled in the art may be able to study the preferred embodiments and identify other ways to practice the invention that are not exactly as described herein. It is the intent of the inventors that variations and equivalents of the invention are within the scope of the claims whiles the description, abstract and drawings are not to be used to limit the scope of the invention. The invention is specifically intended to be as broad as the claims below and their equivalents.
This application is a non-provisional application which claims the benefit of and priority to U.S. Provisional Application Ser. No. 61/506,239 filed Jul. 11, 2011, entitled “Advanced, Cellulosic, Low-Sulfur Bunker Fuels,” which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61506239 | Jul 2011 | US |
