Patent Application
20220243130
The present invention relates to the area of low sulphur fuel blend of hydrocarbon containing a renewable component, and method of producing such blend.
Climate changes has forced the international society to set up ambitious goals for reducing the total emissions of greenhouse gases to target a maximum temperature increase of 2° C. by 2050. About 25% of the total greenhouse gas emissions comes from transport, which despite gains in fuel efficiency is the only segment where emissions are still higher than the 1990 levels (i.e. heavy trucks, maritime and aviation) is the only segment where CO2 emissions keep rising compared 1990 levels. Whereas emissions from light vehicles and buses can be reduced by improvements in fuel efficiency, electrification, hybrid cars, bioethanol, such options do not exist for heavy trucking, maritime and aviation, where emissions keep rising, and are predicted to continue to increase. Hence, new solutions are required for such transport applications.
Hydrothermal liquefaction (HTL) is a very efficient thermochemical method for conversion of biogenic materials such as biomass and waste streams into a renewable crude oil in high pressure water near the critical point of water (218 bar, 374° C.) e.g. at pressures from 150 bar to 400 bar and temperatures in the range 300 to 450° C. At these conditions water obtains special properties making it an ideal medium for many chemical reactions such as conversion of bio-organic materials into renewable crude oils. Hydrothermal liquefaction is very resource efficient due to its high conversion and carbon efficiency as all organic carbon material (including recalcitrant bio-polymers such as lignin) is directly converted to a renewable bio-crude oil. It has very high energy efficiency due to low parasitic losses, and, unlike other thermochemical processes no latent heat addition is required as there is no drying or phase change required i.e. wet materials can be processed. Furthermore hydrothermal liquefaction processes allows for extensive heat recovery processes. The renewable crude oil produced has many similarities with its petroleum counterparts and is generally of a much higher quality than e.g. biooils produced by pyrolysis that typically comprise significant amount of heteroatoms such oxygen (e.g. 40 wt %) as well as a high water content (e.g. 30-50 wt %) that makes such bio oils chemically unstable and immiscible in petroleum, and impose serious challenges for their upgrading and/or co-processing into finished products such as transportation fuels. Catalytic hydrodeoxygenation adopted from petroleum hydroprocessing has been proven to at least partly convert bio oils produced by pyrolysis to hydrocarbons or more stable bio oils, but has limitations related to very high hydrogen consumption due to the high oxygen content, catalyst stability and reactor fouling according to published studies e.g. Xing (2019), Pinheiro (2019), Mohan (2006), Elliott (2007).
The quantity and quality of the renewable crude oil produced by hydrothermal liquefaction depends on the specific operating conditions and hydrothermal liquefaction process applied e.g. parameters such as feed stock, dry matter content, pressure and temperature during heating and conversion, catalysts, presence of liquid organic compounds, heating- and cooling rates, separation system etc.
As for conventional petrochemical crude oils, the renewable crude oil produced from hydrothermal liquefaction processes needs to be upgraded/refined such as by catalytic hydrotreating and fractionation, before it can be used in its final applications e.g. direct use in the existing infrastructure as drop in fuels.
However, despite that the renewable crude oils produced by hydrothermal liquefaction resembles its petroleum counter parts in many ways they also has its distinct properties including:
These distinct properties needs to be taken into account both during operation of the hydrothermal production process, the direct use of the renewable crude oil or fractions thereof, and in the upgrading process no matter if it is performed by upgrading the renewable crude oil separately or by co-processing it with other oils such as conventional oils or other oils at refineries.
For use of the renewable oil or fractions thereof in finished fuel blends such as low sulphur fuel blends of hydrocarbons containing a renewable component, it is critical that all components are fully compatible or miscible e.g. do not separate during use, storage and/or by dilution with other fuel blends for use in the same application e.g. marine fuel blends comprising a renewable component fulfilling the ISO 8217 RMG 180 specification for low sulphur RMG 180 marine fuels, hydrocarbon blends for use in stationary engines and/or as heating oils in heating applications.
Further, for process and resource efficiency reasons as well as economic reasons, it is further desirable that as much as possible of the renewable crude oil is converted into useful and valuable products that can be directly used or further processed in the same, and with a minimum of low value residues or waste products generated.
Though such compatibility is desirable, it is typically not obtained for oils comprising a renewable component without generating significant amounts residues, significant amounts of other additives being added, and particularly not for the higher boiling fractions.
Objective of the Invention The object of the present invention is therefore to provide a low sulphur fuel blend comprising a renewable component for use in e.g. marine, stationary engines and/or heating oil applications not suffering from the compatibility issues describes above.
According to one aspect of the present invention the objective of the invention is achieved through a low sulphur fuel blend of a first fuel blend component containing renewable hydrocarbon component(-s) and a second fuel blend component containing hydrocarbon to form at least part of a final low sulphur fuel blend having a sulphur content of less than 0.5 wt. %, where the first fuel blend component is characterised by having the characteristics (δd1, δp1, δh1)=(17-20, 6-10,6-10); where the first fuel blend component comprises a fuel substance comprising 70% by weight of compounds having a boiling point above 220° C. and is further characterized by having the characteristics (δd, δp, δh)=(17-20, 6-15, 6-12) and a linker substance comprising one or more sulphur containing solvents characterised by having the characteristics (δd3, δp3, δh3)=(17-20, 3-6, 4-6); where the fuel substance is present in the first fuel blend component in a relative amount of 90-99.5 wt. %, and the linker substance is present in the first fuel blend component in a relative amount of 0.5 to 10 wt. %; where the second fuel blend component is characterised by having the characteristics (δd2, δp2, δh2)=(17-20, 3-5, 4-7) and selected from the group of ultra low sulfur fuel oils (ULSFO) such as RMG 180, low sulphur fuel oil, marine gas oil, marine diesel oil, vacuum gas oil, and combinations thereof, where the first fuel blend component is present in the final low sulphur fuel blend in a relative amount of up to 80 wt. %.
The low sulphur fuel blends specifications according to the present invention not only allows for more compatible and stable low sulphur blends containing renewable hydrocarbon component(-s) to be produced, but also allowing for more of the first fuel substance containing renewable component(-s) to be introduced into useful and valuable applications without generating significant amount low value residues or waste products e.g. the low sulphur fuel blends according to the present invention allow for all or more of the high boiling fractions of the first fuel substance to be used in the low sulphur fuel blends while maintaining the desirable properties of the final low sulphur fuel blend e.g. for use in marine or heating oil applications. By maximizing of amount that can be used in such low sulphur fuel blends and thereby minimizing the amount of residues or low value products, the overall process efficiency and process economy is improved. Further as the basic idea of using renewable molecules is to reduce greenhouse gas emissions, a higher efficiency in utilization of the renewable molecules such as enabled by the present invention may result in an overall higher decarbonization using existing infrastructure.
As it will be further illustrated in the description of preferred embodiments of the invention, it has been found that a linker substance comprising one or more sulphur containing solvents constitutes an advantageous linker substance to achieve the advantages described above. The use of such sulphur containing linker substance is surprising as the overall aim is produce low sulphur fuel blend with sulphur content of less than 0.5 wt %. In some advantageous embodiments of the present invention, the sulphur content of the low sulphur fuel blend is below 0,1% by weight.
According to the present invention the linker substance may be present in the first in the first fuel component in a concentration from 0,5 to 10% by weight such as in the range from 1.0% by weight to 5.0% by weight.
The concentration of the linker substance in the final low sulphur fuel blend may in many aspects of the present invention be in the range 0,5% by weight to 5.0% by weight such as in the range 1.0 to 4.0% by weight.
Preferred sulphur containing linker substances according to the present invention includes fuel oils with a sulphur content of at least 1% by weight such as a sulphur content of at least 1.5% by weight, preferably a fuel oil having a sulphur content of at least 2.0% by weight. Nonlimiting examples of preferred linker substances according to the invention are high sulphur fuel oil such as RMG 380, vacuum gas oil, heavy vacuum gas oil or a combination thereof. The use of such common higher sulphur containing fuel oils as linker substances further have the advantage of being available at relatively low cost. Other sulphur containing solvents that may be used as linker substances according to the present invention include dimethyl di sulphide and butane thiol.
Generally the first fuel blend component may be present in the final low sulphur fuel blend in a relative amount of up to 80%. In many embodiments of the present invention the first fuel blend component is present in the final low sulphur fuel blend in a relative amount of up between 10-75 wt. %, where the second fuel blend component is present in the final low sulphur fuel blend in a relative amount of between 25-90 wt. %.
In other advantageous embodiments of the present invention the first fuel blend component is present in the final low sulphur fuel blend in a relative amount of between 50-75 wt. %, where the second fuel blend component is present in the final low sulphur fuel blend in a relative amount of between 25-50 wt. %, and where further the linker substance is present in the final low sulphur fuel blend in a relative amount of between 0.5 to 5 wt. %.
The low sulphur fuel blend according to the present invention generally comprises higher amounts of higher boiling compounds than the prior art. In a preferred embodiment the fuel substance comprised by the fuel first fuel blend component containing renewable hydrocarbon component(-s) comprises at least 70% by weight having a boiling point of above 220° C. Preferably the fuel substance comprised by the first fuel component comprises at least 70% by weight having a boiling point above 300° C. such as at least 70% by weight having a boiling point above 350° C.; Often the fuel substance comprised by the first fuel blend component comprises at least 70% by weight having a boiling point above 370° C. such as at least 70% by weight of the fuel substance comprised by the first fuel component having a boiling point above 400° C.
In many embodiments according to the present invention the fuel substance comprised by the first fuel blend component containing renewable hydrocarbon component(-s) comprises at least 50% having a boiling point above 300° C. such as at least 50% by weight of the fuel substance comprised by first fuel component having a boiling point above 350° C.; preferably the fuel substance comprised by the first fuel blend component comprises at least 50% by weight having a boiling point above 370° C. such as a fuel substance comprised by the first fuel blend component having at least 50% by weight having a boiling point above 400° C.
In a further preferred embodiment, the fuel substance comprised by the first fuel blend component containing renewable hydrocarbon component(-s) comprises at least 10% by weight having a boiling point above 400° C. such as at least 10% by weight of the fuel substance comprised by the first fuel component having a boiling point above 450° C.; preferably the fuel substance of the first fuel blend component comprises at least 10% by weight having a boiling point above 475° C. such as a fuel substance of the first fuel blend component comprising at least 10% by weight of having a boiling point above 500° C.
The water content of the fuel substance comprised by the first fuel blend component containing renewable hydrocarbon component(-s) may according to a preferred embodiment of the present invention have a water content of less than 1% by weight such as a water content of less than 0,5% by weight; preferably the fuel substance comprised by the first fuel blend component containing renewable hydrocarbon component(-s) have a water content of less than 0,25% by weight such as a water content of less than 0.1 wt %.
The oxygen content of the fuel substance comprised by the first fuel blend component is in preferred embodiments according to the present invention below 15% by weight such as an oxygen content of the fuel substance less than 12% by weight; preferably the fuel substance of the first fuel blend component have an oxygen content of less than 10% by weight such as an oxygen content of less than 8% by weight.
In a preferred embodiment of the present invention, the second fuel blend component according to the present invention have a sulphur content of up to 1% by weight, such as up to 0.5% by weight.
Hansen solubility parameters as will be explained and illustrated further in the detailed description of the a preferred embodiment of invention and examples, are used in the present invention to precisely characterize the different blend components of the low sulphur fuel blend to ensure full compatibility and miscibility of components the blend in the full concentration ranges according to the present invention e.g. the final low sulphur fuel blend may e.g. be diluted with more secondary fuel component as long as the resulting blend is maintained within the specified characteristics and concentration ranges without that the resulting mixture looses its compatibility/miscibility whereby e.g. separation such as sedimentation in fuel tanks may be avoided in case that the tank should be filled and diluted with another fuel having the properties specified for the second fuel blend component e.g. if the low sulphur fuel blend according to the present invention should not be available.
According to the invention the first fuel blend component containing a renewable fuel component comprises a fuel substance and a linker substance. The first fuel blend component according to the present invention is generally specified by having characteristic Hansen Solubility parameters in the ranges (δd1, δp1, δh1)=(17-20, 6-10, 6-10). A preferred embodiment is where the first fuel blend component is characterised by having the characteristic Hansen Solubility Parameters (δd1, δp1, δh1)=(17-20, 7-9, 8.5-10);
The fuel substance comprised by the first fuel blend component may according to the present invention be characterized by the characteristic Hansen solubility parameters (δd, δp, δh)=(18.0-19,5, 6-12, 7-10) and the linker substance according to the invention may be characterized by having Hansen solubility parameters in ranges (δd3, δp3, δh3)=(17-20, 3-4.5, 4-6.5). Thereby the criteria of the Hansen solubility criteria for the first fuel blend component above is fulfilled.
The second fuel blend according to the present invention is generally characterised by having the characteristic Hansen solubility parameters (δd2, δp2, δh2)=(17-20, 3-5, 4-7) and selected from the group of ultra low sulfur fuel oils (ULSFO) such as RMG 180, low sulphur fuel oil, marine gas oil, marine diesel oil, vacuum gas oil, and combinations thereof.
In some embodiments of the present invention, the linker substance further comprises components from the group of ketones, alcohols, toluene, xylene and/or creosol or combination thereof.
In a preferred embodiment of the present invention the linker substance comprises a further mixture of components comprised by 25-90% by weight of ketones, 0.1-40% by weight of alkanes, 1-40% by weight alcohols and 0.1-20% by weight of toluene and/or xylene and/or creosol.
A preferred embodiment of the present invention is where the low sulphur fuel blend have a viscosity at 50° C. in the range 160-180 cSt, a flash point above 60° C., a pour point of less than 30° C., and a total acid number of less than 2.5 mg KOH/g.
Advantageously the first fuel component containing a renewable component is further characterized by having:
In a preferred embodiment the first fuel component containing renewable hydrocarbon have an oxygen content of less than 5% by weight,
The first fuel component containing renewable hydrocarbon may further be characterized by having a viscosity at 50° C. in the range of 1000-10000 cSt such as a viscosity at 50° C. in the range 100-1000 cSt.
The fuel substance comprised by first fuel component containing renewable hydrocarbon is according to a preferred embodiment of the present invention produced from biomass and/or waste.
In a particularly proffered embodiment the production of the fuel substance comprised by the first fuel blending component is produced by a hydrothermal liquefaction process.
In an advantageous embodiment of the fuel substance of the first fuel component containing renewable sources is produced by a hydrothermal liquefaction process by
a. Providing one or more biomass and/or waste materials contained in one or more feedstock;
b. Providing a feed mixture by slurring the biomass and/or waste material(-s) in one or more fluids at least one of which comprises water;
c. Pressurizing the feed mixture to a pressure in the range 100 to 400 bar;
d. Heating the pressurized feed to a temperature in the range 300° C. to 450° C.;
e. Maintaining the pressurized and heated feed mixture in a reaction zone in a reaction zone for a conversion time of 3 to 30 minutes.
f. cooling the converted feed mixture to a temperature in the range 25° C. to 2000° C.
g. Expanding the converted feed mixture to a pressure of 1 to 120 bar;
h. Separating the converted feed mixture in to a crude oil, a gas phase and a water phase comprising water soluble organics and dissolved salts; and eventually a solid product phase;
i. Optionally further upgrading the crude oil by reacting it with hydrogen in the presence of one or more heterogeneous catalysts in one or more steps at a pressure in the range 60 to 200 bar and a temperature of 260 to 400° C.; and separating the upgraded crude oil into a fraction comprising low boiling compounds and a first fuel component comprising high boiling compounds.
The carbon foot print of the low sulphur fuel blend comprising a renewable component according to the present invention is generally lower than its fossil counter part. Typically the carbon foot print of the blend is at least 25% less than its fossil counter part, such as at least 35% less than its fossil counter part; preferably the low sulphur blend has a carbon foot print of at least 50% less than its fossil counter part such as at least 65% less than its fossil counter part.
The objective of the invention is further achieved by providing an intermediate blend component for forming a low sulphur fuel blend according to any of the preceding claims, the intermediate blend component comprising a fuel substance containing hydrocarbon and a linker substance to form at least part of the intermediate blend component, where the fuel substance is characterised by having the characteristics (δd, δp, δh)=(17-20, 6-12, 7-10) and where the linker substance is characterised by having the characteristics (δd3, δp3, δh3)=(17-20, 3-6, 3-6); where the fuel substance is present in the intermediate blend component in a relative amount of between 90-99.5 wt. % and where further the linker substance is present in the intermediate blend component in a relative amount of between 0.5 to 10 wt. %.
Preferably the fuel substance is present in the intermediate blend component in a relative amount of up between 95-99.5 wt. % and where further the linker substance is present in the final blended fuel in a relative amount of up between 0.5 to 5 wt. %.
The objective is still further achieved by a method of producing a blended fuel containing a renewable hydrocarbon component and having a sulphur content of less than 0.5% by weight, where the method comprises the steps of:
An advantageous embodiment is where the method further comprises the steps of:
The first fuel blend component and/or the second fuel component may according to a preferred embodiment be heated to a temperature in the range 70-150° C. prior to forming the low sulphur fuel blend.
The intermediate blend component comprising the first or the second fuel component and the linker substance is advantageously manipulated to form a homogenous mixture prior to adding the second or the first fuel component to the first mixture hereby forming the low sulphur fuel blend. The manipulation to form a homogenous mixture may be carried by stirring the mixture or by pumping the mixture.
In a further aspect of the invention the objective is achieved through a method for preparing the production of a low sulphur fuel blend according to the invention, the method comprising measuring the characteristics (δd1, δp1, δh1) of a first fuel blend component containing a renewable hydrocarbon component, measuring the characteristics (δd2, δp2, δh2) of a second fuel blend component, determining the compatibility of the first and the second fuel component based on the measurement of the characteristics.
In one embodiment the compatibility is determined to be present based on the measured characteristics and the first and the second fuel components are accepted for direct mixing.
In a further embodiment the first and the second fuel component are determined to be incompatible based on the measured characteristics, where a linker substance is selected having characteristics ((δd3, δp3, δh3)) and where the linker substance is added to the first or the second fuel component to achieve compatibility.
The invention will be described in the following with reference to one embodiment illustrated in the drawings where:
As shown in
Non limiting examples of biomass and waste according to the present invention include biomass and wastes such as woody biomass and residues such as wood chips, saw dust, forestry thinnings, road cuttings, bark, branches, garden and park wastes and weeds, energy crops like coppice, willow, miscanthus, and giant reed; agricultural and byproducts such as grasses, straw, stems, stover, husk, cobs and shells from e.g. wheat, rye, corn rice, sunflowers; empty fruit bunches from palm oil production, palm oil manufacturers effluent (POME), residues from sugar production such as bagasse, vinasses, molasses, greenhouse wastes; energy crops like miscanthus, switch grass, sorghum, jatropha; aquatic biomass such as macroalgae, microalgae, cyano bacteria; animal beddings and manures such as the fiber fraction from livestock production; municipal and industrial waste streams such as black liquor, paper sludges, off spec fibres from paper production; residues and byproducts from food production such as pomace from juice, vegetable oil or wine production, used coffee grounds; municipal solid waste such as the biogenic part of municipal solid waste, sorted household wastes, restaurant wastes, slaughter house waste, sewage sludges such as primary sludges, secondary sludges from waste water treatment, digestates from anaerobic digestion and combinations thereof.
Many carbonaceous materials according to the present invention are related to lignocellulose materials such as woody biomass and agricultural residues.
Such carbonaceous materials generally comprise lignin, cellulose and hemicellulose.
An embodiment of the present invention includes a carbonaceous material having a lignin content in the range 1.0 to 60 wt. % such as lignin content in the range 10 to 55 wt. %. Preferably the lignin content of the carbonaceous material is in the range 15 to 40 wt. % such as 20-40 wt. %.
The cellulose content of the carbonaceous material is preferably in the range 10 to 60 wt. % such as cellulose content in the range 15 to 45 wt. %. Preferably the cellulose content of the carbonaceous material is in the range 20 to 40 wt. % such as 30-40 wt. %.
The hemicellulose content of the carbonaceous material is preferably in the range 10 to 60 wt. % such as cellulose content in the range 15 to 45 wt. %. Preferably the cellulose content of the carbonaceous material is in the range 20 to 40 wt. % such as 30-40 wt. %.
The second step is a pressurization step (2) where the feed mixture is pressurized by pumping means to a pressure of at least 150 bar and up to about 450 bar.
The pressurized feed mixture is subsequently heated to a reaction temperature in the range from about 300° C. and up to about 450° C.
The feed mixture is generally maintained at these conditions in sufficient time for conversion of the carbonaceous material e.g. for a period of 2 to 30 minutes before it is cooled and the pressure is reduced.
The product mixture comprising liquid hydrocarbon product, water with water soluble organics and dissolved salts, gas comprising carbon dioxide, hydrogen, and methane as well as suspended particles from said converted carbonaceous material is subsequently cooled to a temperature in the range 50° C. to 250° C. in one or more steps.
The cooled or partly cooled product mixture thereafter enters a pressure reducing device, where the pressure is reduced from the conversion pressure to a pressure of less than 200 bar such as a pressure of less than 120 bar.
Suitable pressure reduction devices include pressure reduction devices comprising a number of tubular members in a series and/or parallel arrangement with a length and internal cross section adapted to reduce the pressure to desired level, and pressure reducing devices comprising pressure reducing pump units.
The converted feed mixture is further separated into at least a gas phase comprising carbon dioxide, hydrogen, carbon monoxide, methane and other short hydrocarbons (C2-C4), alcohols and ketones, a crude oil phase, a water phase with water soluble organic compounds as well as dissolved salts and eventually suspended particles such as inorganics and/or char and/or unconverted carbonaceous material depending on the specific carbonaceous material being processed and the specific processing conditions.
The water phase from the first separator typically contains dissolved salts such as homogeneous catalyst(-s) such as potassium and sodium as well as water soluble organic compounds. Many embodiments of continuous high pressure processing of carbonaceous material to hydrocarbons according to the present invention include a recovery step for recovering homogeneous catalyst(-s) and/or water soluble organics from said separated water phase, and at least partly recycling these to the feed mixture preparation step. Hereby the overall oil yield and energy efficiency of the process is increased. A preferred embodiment according to the present invention is where the recovery unit comprises an evaporation and/or distillation step, where the heat for the evaporation and/or distillation is at least partly supplied by transferring heat from the high pressure water cooler via a heat transfer medium such as a hot oil or steam, whereby the overall heat recovery and/or energy efficiency is increased.
The renewable crude oil may further be subjected to an upgrading process (not shown) where it is pressurized to a pressure in the range from about 20 bar to about 200 bar such as a pressure in the range 50 to 120 bar, before being heated to a temperature in the range 300 to 400° C. in one or more steps and contacted with hydrogen and heterogeneous catalyst(s) contained in one or more reaction zones, and eventually fractionated into different boiling point fractions.
Three different renewable crude oils Oil A, Oil B, and Oil C was produced from Birch and Pine wood using the pilot plant in
Feed Preparation
The wood chips were sized reduced to wood flour in a hammer mill system and mixed with recycled water (inclusive dissolved salts and water soluble organics), recycled oil, catalysts to produce a homogeneous and pumpable feed mixture. Potassium carbonate was used as catalyst and sodium hydroxide was used for pH adjustment. It was attempted to keep the potassium concentration constant during the runs i.e. the potassium concentration in the water phase was measured and the required make-up catalyst concentration was determined on this basis. Sodium hydroxide was added in amounts sufficient to maintain the outlet pH of the separated water phase in the range 8.0-8.5. Further CMC (Carboxy Methyl Cellulose, Mw=30000) in a concentration of 0.8 wt. % was added to the feed slurry as a texturing agent to avoid sedimentation in the feed barrel and improve pumpability.
As neither water nor oil phases was available for the first cycle (batch), crude tall oil was used as start up oil and 5.0 wt. % ethanol and pure water (Reversed Osmosis water, RO water) was used to emulate the water phase in the first cycle. Multiple cycles (batches) are required before the process can be considered in steady state and representative oil and water phases are produced. Approximately 6 cycles are required to produce oil with less than 10% concentration of the start up oil. Hence, 6 cycles were carried out, where the oil and water phase produced from the previous cycle was added to the feed mixture for the subsequent cycle. The feed composition for the 6th cycle run is shown in Table 2 below:
The feed mixture in Table 2 were all processed at a pressure of about 320 bar and a temperature around 400° C. The de-gassed product was collected as separate mass balance samples (MB) in barrels from the start of each test, and numbered MB1, MB2, MB3, etc. The collected products were weighed, and the oil and water phases were gravimetrically separated and weighed. Data was logged both electronic and manually for each batch.
Total Mass Balance
The Total mass balance (MBTot) is the ratio between the total mass leaving the unit and the total mass entering the unit during a specific time. The total mass balance may also be seen as a quality parameter of the data generated. The average value is 100.8% with a standard deviation of
Oil Yield from Biomass (OY)
The Oil Yield from Biomass (OY) expresses the fraction of incoming dry biomass that is converted to dry ash free oil. It's defined as the mass of dry ash free Oil produced from dry biomass during a specific time divided by the mass of dry biomass entering the unit during the same time. The recirculated oil is not included in the balance, it's subtracted from the total amount of oil recovered when calculating the oil yield from biomass. The average oil yield (OY) was found to be 45.3 wt. % with a standard deviation of 4.1 wt. % i.e. 45.3% of the mass of dry biomass (wood+CMC) in the feed is converted to dry ash free Oil.
Detailed Oil Analysis
Data measured for the oil is presented in Table 3.
Energy Recovery In the produced Hydrofaction Oil
The Energy Recovery (ER0il) expresses how much of the chemical energy in the fed wood that are recovered in the oil. It does not take into account the energy required for heating nor the electrical energy supplied to the unit. For the calculations of recoveries, a High Heating Value (HHV) for the oil of 38.6 MJ/kg were used together with the HHV for the wood mixture given in Table 1. The resulting energy recovery for the 6th cycle oil was 85.6% with a standard deviation of 7.7 i.e 85.6% of the (chemical) energy in wood fed to the plant is recovered in the produced oil.
Gas Production and Gas Analyses
Gas is produced in the process of converting biomass into oil. The yield of gas produced from dry wood in the feed is 41.2 wt. %. The gas is composed of mainly CO2, CH4 and other short hydrocarbons (C2-C4), H2 and some lower alcohols. Gas was sampled and analyzed by Sveriges Tekniska Forskningsinstitut (SP) in Sweden. The analysis of 6a, cycle gas is shown in Table 4 along with heating values of the gas estimated from the gas composition. Since a HTL process runs at reductive conditions, it's assumed that the gas is oxygen (O2) free and the detected oxygen in the gas origin from air leaking into the sample bags when filled with gas sample. The gas composition is corrected for the oxygen (and nitrogen). The calculated elemental composition of the gas is shown in Table 4.
Renewable crude oil—Oil A, B and C—produced from pine wood as described in example 1 was subjected to a partial upgrading by hydroprocessing as shown in
The process was carried out in a continuous pilot-plant unit, using a down-flow tubular reactor. Three independent heating zones where used to ensure and isothermal profile in the catalysts bed. Therefore, the reactor allocates three sections including pre-heating zone, catalysts bed (isothermal zone) and outlet zone. The reactor was filled with a 25% to 50% degraded catalyst with silicon carbide inert material. A commercial NiMo-S catalyst was used.
The catalysts bed was first dried in a nitrogen atmosphere at temperatures in the range of 100-130° C., and subsequently activated by a pre-sulfiding process using sulphur-spiked diesel with 2.5 wt. % of Dimethyl Disulfide and hydrogen flow rate of 24 L/hr at 45 bar and temperature between 25 to 320° C. (35/h rate) for about 40 hours or until sulphur saturation levels were off, i.e. until the hyperactivity of the catalyst wears off. This was monitored via sulphur product saturation or change in liquid gravity; once the product gravity was stable, the renewable crude oil was introduced to the system at the desired flow.
The weight hour space velocity (WHSV) was varied in the range 0.2 to 0.5 h−1, at a constant flow of hydrogen (900 scc H2/cc of oil), operating pressure of 90 bar and the operation temperature of the isothermal zone containing the heterogeneous catalyst was 320° C.
The resulting partially upgraded oil quality had the following properties (table 6).
The results presented in table 6 indicate that decreasing the space velocity the water increases while the viscosity, oxygen content and TAN are reduced. This effect is related to higher reactions rated of decarboxylation/methanation and hydrodeoxygenation/dehydration reactions.
Partially upgraded oil produces as described in example 2 was subjected to a further stage of hydro-processing as shown in
The process was carried out in a continuous pilot-plant unit, using a down-flow tubular reactor. Three independent heating zones where used to ensure and isothermal profile in the catalysts bed. Therefore, the reactor allocates three sections including pre-heating zone, catalysts bed (isothermal zone) and outlet zone. The reactor was filled with a 50% degraded catalyst with silicon carbide inert material. A commercial NiMo-S catalyst was used.
The catalysts bed was first dried in a nitrogen atmosphere at temperatures in the range of 100−130° C., and subsequently activated by a pre-sulfiding process using sulphur-spiked diesel with 2.5 wt. % of Dimethyl Disulfide and hydrogen flow rate of 24 L/hr at 45 bar and temperature between 25 to 320° C. (35/h rate) for about 40 hours or until sulphur saturation levels were off, i.e. until the hyperactivity of the catalyst wears off. This was monitored via sulphur product saturation or change in liquid gravity; once the product gravity was stable, the renewable crude oil was introduced to the system at the desired flow.
The weight hour space velocity (WHSV) was 0.3, at a constant flow of hydrogen (1300 scc H2/cc of oil), operating pressure of 120 bar and operation temperature of the isothermal zone containing the heterogeneous catalyst was 370° C. A significant reduction of boiling point and residue is obtained after hydroprocessing the partially upgraded oil as shown in Table 7. i.e. the fraction from the initial boiling point (IBP) to 350° C. is more than doubled by the upgrading process, and the residue (BP>550° C.) was reduced from 16.3.% to 7.9%.
Hansen Solubility Parameters (HSP) is a methodology for describing the solubility, blendability and stability of various solvents and substances and is widely used in e.g. the polymer and paint industries. A good description of the methodology is given in C. M. Hansen, “Hansen Solubility Parameters—A Users Handbook”, Second Edition, CRC Press, Taylor & Francis Group, LLC. (2007), hereby incorporated herein as reference.
The methodology takes three types of molecular interactions into consideration: ΔEd for dispersion (related to van der Waals forces); ΔEp for polarity (related to dipole Moment) and, ΔEh for hydrogen bonding, (Eq.1). The total solubility parameter (δT), is obtained by dividing equation 1 by the molar volume yields (Eq.2).
ΔE=ΔEd+ΔEp+ΔEh (Eq.1)
δT2=δd2+δp2+δh2 (Eq.2)
As described by Hansen, these three parameters can be illustrated in a 3D diagram as a fixed point for pure solvents and as a solubility sphere for complex mixtures samples. The center of a solubility sphere corresponds to its Hansen Solubility parameters and its radius (R0), or so-called interaction radius, determines the boundary of suitable solvents, which are normally contained within the sphere, with the insoluble solvents located on the outside of the sphere. Hansen Solubility Parameters is based on “like dissolves like” principle in which the Hansen Solubility Parameter distance metric measures likeness, which means solvents with similar values of δD, δp, and δH parameters are likely to be compatible.
When a solubility profile is determined on complex mixtures, there are two parameters that should be included in the study, the distance between materials (Ra) in the sphere plots and the relative distance of one solvent or mixture of two or more solvents from the centre of the sphere (RED number). Ra can be determined by volume or weight additivity of the respective parameters (Eq. 3), and the RED number corresponds to the ratio between Ra and the sphere radius (R0) (Eq.4)
The relative distance RED is equal to 0 when the solvent and the sample under investigation have the same Hansen Solubility Parameters; compatible solvents or mixture thereof will have RED values less than 1 and, the RED value will increase gradually with the reduction of solubility in between solvent and solute.
Determination of Hansen Solubility Parameters
The Hansen Solubility Parameters for renewable crude oils Oil A, Oil B, Oil C produced in example 1 and upgraded renewable oils from example 2 and 3 as well as different fossil crude oils and boiling point fractions were determined using the solvents and procedures described below.
Materials
For comparison purpose, solubility profiles of a fossil crude oil was determined. For the solubility tests, the following solvents acquired from commercial chemical suppliers were used: 1-propanol (≥99.5%), 1-butanol (99.8%), 2-butanone (≥99.0%), 2-heptanone (≥98%), acetaldehyde (≥99%), acetyl chloride (≥99.9%), acetone (≥99.9%), acetonitrile (≥99.9%), acetylacetone (≥99%), 1-Butanethuil (99%)cyclohexane (≥99.5%), cyclopentanone (≥99%), diethyl ether (≥99.0%), ethyl acetate (99.8%), furfural (≥98%), hexanal (≥97%), hexane (≥97.0%), isopropyl acetate (98%), lactic acid solution (≥85%), m-cresol (99%), methanol (≥99.9%), pentane (≥99%), phenol liquid (≥89.0%), tetrahydrofural (≥99.9%), toluene (99.8%) Sigma-Aldrich. Tetrahydrofurfuryl alcohol (99%), 1-methylimidazole (99%), 2,6 dimethylphenol (99%), dimethyl disulfide (≥99.0%), glycidyl methacrylate (≥97.0%), trirolyl phosphate (90%) Aldrich. 2-methoxyphenol (≥98%), anisole (99%), dichloromethane (≥99.5%), propylene oxide (≥99%) Alfa Aesar. Glycerol and ethylene glycol (general use) BDH. Hydrogen peroxide (USP-10 volume) Atoma.
Procedure for the Estimation of the Hansen Solubility Parameters
The Hansen Solubility Parameters of the oils studied were determined by a set of solubility tests and HSP model described in in C. M. Hansen, “Hansen Solubility Parameters—A Users Handbook”, Second Edition, CRC Press, Taylor & Francis Group, LLC. (2007), and HSPiP software written by Abbott S. & Yamamoto H. (2008-15).
Initially, 20 organic solvents were mixed with the oils in question at ambient temperature and classified as “goo” (i.e. soluble), “partially soluble” or “bad” (i.e. insoluble) solvents based on the observed and measured degree of solubility.
As the solubility parameters of the oils studied were unknown, the set of solvents used for the first screening had a wide range of Hansen Solubility Parameters. After the initial solubility tests were completed and a first approximation of HSP achieved, solvents with Parameters closer to those of the oil studied were selected in order to increase the precision of the Hansen Solubility Parameter model. A pseudo-3-D representation (sphere) of the Hansen Solubility Parameters was built from the initial results using the HSPiP software is shown in
In this representation, the “good” solvents are placed inside or on the surface of the sphere, while partially soluble or insoluble solvents are placed outside the sphere. Once the initial Hansen Solubility Parameters are determined for the oil studied, the software estimates the relative distance (RED) by equation 5. RED is the ratio of the modified difference between the solubility parameters of two substances, Ra (i.e. samples under study and a solvent), and the maximum solubility parameter difference, which still allows the sample to be dissolved in the solvent, RM.
Thus, the relative distance RED is equal to zero (RED=0) when the solvent and the sample under investigation have the same Hansen Solubility Parameters. Red is equal to 1 (RED=1) when the HSPs of the solvent are placed on the surface of the sphere, and RED is greater than 1 (RED>1) when the sample is insoluble in the solvent, or the solvent is a poor solvent. Once the approximate Hansen Solubility Parameters and RED values are estimated for the oil in question, the precision of the model can be increased.
This is achieved by performing solubility tests with a new set of solvents or mixtures of solvents selected based on their RED values as predicted by the HSPiP software. Hansen Solubility Parameters of both tested solvents and mixtures should be placed on the surface and near to the center of the 3D sphere model. After the model is refined, the software HSPiP can be used as a prediction tool of suitable solvents depending on the function required; i.e. bridge of solubility, emulsion breaker, precipitation of insoluble material on a determined chemical. A list of solvents and solvent mixtures used is presented in
The solubility tests were performed in a set of conical glass tubes with cap, by placing approximately 0.5 g of one sample and 5 ml of a solvent or mixture. The solubility tests were performed in triplicate. The tubes were kept under sonication for 5 hours and allowed to rest overnight at room temperature. Subsequently, the contents of each tube were visually inspected and classified in 5 categories as: soluble(1): when there is no observable phase separation or solid precipitation in the glass tubes; partially soluble (2-4) when big solids or a lump of oil appears, indicating that the sample is not completely dissolved in the solvent or the mixture; and, not soluble (0) are those mixtures that have well-defined phases. The degree of partial solubility ranges from 2 to 4, with 2 indicating the highest relative solubility
Due to the dark color of the samples, it is difficult to visually distinguish between the categories soluble (1) and partially soluble (2) so these samples were marked “uncertain. To assess the solubility of these “uncertain samples, the “spot test” method was used as a more precise blend stability/compatibility indicator. This method is widely used to assess the compatibility of marine fuel blends and has been used e.g by Redelius [P. Redelius, “Bitumen solubility model using hansen solubility parameter,” Energy and Fuels, vol. 18, no. 4, pp. 1087-1092, 2004] for Hansen Solubility Parameter analysis. The spot test was performed by placing a drop of each “uncertain solution on a filter paper, and evaluated based on the criteria of the spot test method given in P. Products, and R. S. Sheet, “Cleanliness and Compatibility of Residual Fuels by Spot Test,” vol. 4, no. Reapproved 2014, pp. 2014-2016, 2016: If a uniform color spot is formed as shown in
The Hansen Solubility Parameters and solubility profiles of the renewable crude oils produced by hydrothermal liquefaction in example 1 (Oil A, B and C) were determined using a total of 36 solvents and 23 solvent mixtures. The results are summarized in
The three renewable crude oils, Oil A (δD: 19.19, δp: 14.52, δH: 11.61, R0-9.3), Oil B (δD: 18.36, δP: 10.43, δH: 10.06, R0: 6.7), and Oil C (δD: 18.13, δP: 9.59, δH: 9.25, R0: 6.8) have similar solubility profiles and can be visualized in FIG. However, Oil A has higher polarity and stronger hydrogen bonding interactions than oils B and C. Comparing the parameters for the three biocrudes, it can be seen that they are similar with the only exception being that Oil C was partially soluble in 1-Methyl imidazole while oils A and B were soluble as seen in
The Hansen Solubility Parameters Score and RED values obtained for partially upgraded renewable oils in the example 2 are summarized in
As shown in
As seen from
The RED value of the partially upgraded oil in the solubility sphere of the biocrude oil, is rather low (0.524) suggesting full solubility. However, the RED value of the upgraded oil (RED=0.934) is close to the solubility limit of RED≥1 showing poor solubility in the biocrude. Therefore the solubility between biocrude and upgraded oil is inversely proportional to the degree of upgrading thereof.
Compatibility of the renewable oil with petroleum oils are important for many practical applications of the renewable oil e.g. for co-processing in petroleum refineries and for transport in pipelines.
A Hansen Solubility Parameter analysis was used to test compatibility of upgraded renewable oil with Vacuum Gas Oil—VGO, bitumen and petroleum crude such purposes. The results are shown in
To assess co-processing of renewable crude oil and/or partially upgraded renewable oil with petroleum crude oil and heavy petroleum crude oil fractions such as Vacuum Gas Oil (VGO) the solubility profiles of a petroleum crude oils were determined. A total of 21 solvents were used to determine the Hansen Solubility Parameters of the fossil crude oil (δD: 18.47, δP: 6.67, δH: 3.58) and VGO (δD: 19.1-19.4, δP: 3.4-4.2, δH: 4.2-4.4). Its 3D representation has a great fit of 1.000 with a radius of solubility of 5.6 and 5.8, respectively
Even though the disperse interaction parameters of the biocrude, fossil crude oil, VGO and bitumen are similar, there is a considerable difference in the polarity and hydrogen bonding interaction parameters. The RED values of fossil oil, VGO and Bitumen in the solubility sphere of biocrude are 1.248, 1.415 and 1.506, respectively. These RED values are above the limit of solubility RED≥1 showing only partial solubility in the biocrude (
Compatibility of fractions of raw biocrude, partially upgraded oil and upgraded oil with its fossil counterparts is important to evaluate those blends in process such as recirculation in renewable oil hydroprocessing and co-processing with petroleum fractions and/or other bio-oils. Therefore, the Hansen Solubility Parameters of the fractions listed below were determined by methodology described in example 5. The upgraded fractions were obtained by distillation of the partially upgraded and upgraded oils were produced as described in examples 2 and 3.
18-19.5
7-10.5
As seen from
Fully compatible synthetic diluents or viscosity and/or density reducing agents for the renewable crude oil are desirable for many practical applications including diluents to improve fluidity of the renewable crude oil, enhance separation efficiency during the production process e.g. by solvent/diluent assisted separation of the renewable crude oil or to improve the storage stability of the crude oils.
Using the solubility profile of the biocrude, a list of solvents were selected that fit within the sphere of “Oil A” Hansen Solubility Parameters solubility profile. These solvents were selected as suitable to compose the desired “synthetic lights” mixture.
This list of solvents was further narrowed using the following criteria: a) low-toxicity, b) ease of separation from the renewable crude oil e.g. by boiling point, c) non-complex geometry, d) solvents that do not contribute increasing the oxygen content of the biocrude, e) solvents that do not contain other heteroatoms (i.e. Nitrogen, sulfur, chloride, etc.) or metals that can contribute to the deterioration of the quality of the biocrude f) local availability of solvents and g) cost.
A light fraction with a cut off boiling point of 130° C. was from renewable crude oil A produced in example 1 produced in a rotary evaporator. The families of compounds that represent the major volume percentages of the renewable crude light fraction were established based on the gas chromatography analysis of the renewable crude oil light, i.e. Substituted benzenes: 15 vol. %, C4-C6 ketones: 50 vol. %, alkanes: 24 vol. % and alcohols: 11 vol. %.
Based on this approach, a mixture containing methyl ethyl ketone, alkanes (e.g. octane, nonane), p-xylene and/or toluene, and 1-butanol and/or propanol was identified as suitable to emulate the light ends of the renewable crude oil as “synthetic lights”.
ap-xylene may be substituted by toluene, or by a solvent mixture of toluene/xylene 50%/50%
The volume percentages of each solvent in the selected mixture are shown in table 9. The initial value of RED score (1.53) of Hansen Solubility Parameters of a similar mixture (table 9) was obtained using the volume concentration of the lights obtained by GC-MS.
Table 9 further show some volume concentrations of the solvent mixture that have similar RED values, which means that all the mixtures proposed are close enough to the behaviour of the real light mixture from the renewable crude oil.
The Hansen Solubility parameters for solvents and linker substances are shown in table 10.
For a selection of solvents that fulfill all the above solubility and usability criteria, various linker substances such as solvent combinations were screened on the HSPiP software to identify suitable mixtures that do not exceed the solubility limit i.e. RED≤1.
Through the testing of a number of solvents and mixtures; it was confirmed that 1) the addition of 2 wt. % of Toluene or the blend MEK/m-cresol (70:30) increase the solubility of biocrude and Bitumen. Although the mixture were not fully compatible at room temperature, it becomes compatible by spot test analysis when the blend is heated to 150° 2) Biocrude and Vacuum Gas Oil (VGO) blend become compatible by the addition 2 wt. % of solvent mixtures with HSP of about δD15.6, δP: 8.3, δH: 9.4. e.g Acetone (60 wt. %)+Propanol (30 wt. %)+pentane (10 wt. %). 3) Partially upgraded oil and VGO blends are compatible in a proportion up to 25% of Partially upgraded oil without the use of linkers.
Blending tests were performed in order to test the solubility of low sulphur marine fuel blendstocks with renewable liquids (crude oil, partially upgraded renewable oils and the 350+° C. boiling fractions from the same oils) using concentrations in the range of 2 to 50 wt. % of renewable liquids. The tests showed only partial solubility of the renewable liquids with low sulfur marine fuel blendstock (RMG 180 Ultra Low sulphur fuel oil according to the IS08217 (2012) standard), at any of the blending ratios tested. Obviously, such blend stock has compatibility issues that lead to precipitation, separation, and/or sedimentation of the insoluble components, etc. if used directly in blends with other marine fuels. Hence, a renewable blendstock not suffering from such compatibility issues are highly desirable.
A Hansen Solubility profile analysis was performed in order to identify a linker substance that will enable the blending of liquids in marine fuels. As visualized in
The identified potential mixtures of solvents that may acts as linker substances are mainly composed of sulfur-containing solvents, ketones, alkanes, and alcohols as well as aromatic compounds like toluene, xylene, and creosol.
Based on the solubility profiles described in example 12 first fuel blend components containing a renewable component were produced from the heavy fraction of upgraded renewable crude oil having a boiling point of 350+° C. and the Hansen Solubility Parameters (δD: 17-18.5, δP: 7-9.5, δH: 7-10.5; R0: 4-8), and a linker substance comprising RMG380 high sulphur fuel oil (HSFO) with the Hansen Solubility Parameters (δD: 18-19.7, δP: 3-6, δH: 3-6; R0: 4-6) and a sulphur content of 2.49% by weight in concentrations from 0 to 10 wt. %.
The first fuel blend components with the different linker substance concentrations up to 10% by weight were mixed with a second fuel component comprising ultra low sulphur fuel oil (ULSFO) according to the ISO 8217 RMG 180 ultra low sulphur specification having Hansen Solubility Parameters (δD: 18-19.7, δP: 3-6, δH: 3-4.5; R0: 4-6.5).
As expected, the first fuel blend component without the linker substance was found to be incompatible when mixed the upgraded heavy fraction with two marine fuels (i.e. ultralow sulphur and high sulphur marine fuels) in proportions of 5 to 50 wt. % of upgraded renewable fraction. However, for first fuel blend components comprising 2% by weight or higher of the high sulphur linker substance the blends were found to be compatible. It was further found that the low sulphur fuel blend remained compatible at all ratios by dilution with the ultra low sulphur fuel oil (ULSFO) e.g. ultra low sulphur fuel oil can be added to the same tank as the low sulphur fuel blend according to the present invention without any compatibility issues.
An example of the properties of a low sulphur fuel blend according to the present invention is shown in
Blending tests were performed using of a first fuel blend component comprising the heavy fraction (Boiling point 350+° C.) from example 10 with an oxygen content of 3 wt. % and a second fuel blend component comprising marine gas oil (MGO) according to the ISO 8217 DMA standard. The heavy fraction had the Hansen Solubility Parameters (δD: 17-19, δP: 7.5-12, δH: 7-10; R0: 5-9) and Marine Gas Oil (MGO) had the Hansen Solubility Parameters (δD: 18-19.7, δP: 3-6, δH: 3-5; R0: 4.5-6.5). As the RED centers of solubilities are higher than 1 why the blends is expected to be only partially soluble without a linker substance according to the present invention. As seen from spot tests and microscope tests in
Blending tests were performed using of a first fuel blend component comprising the heavy fraction (Boiling point 350+° C.) from example 10 with an oxygen content of 3 wt. % and a second fuel blend component comprising marine gas oil (Ultra Low Sulphur Fuel Oil) according to the ISO 8217 DMA standard. The heavy fraction had the Hansen Solubility Parameters (δD: 17-19, δP: 7.5-12, δH: 7-10; R0: 5-9) and High Sulphur Fuel Oil had the Hansen Solubility Parameters (δD: 18-19.7, δP: 3-6, δH: 3-6; R0: 3-6). As the RED centers of solubilities are close to 1, the blends are expected to be soluble or compatible without a linker substance according to the present invention. As seen from spot tests and microscope tests in
| Number | Date | Country | Kind |
|---|---|---|---|
| PA 2019 00581 | May 2019 | DK | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/025222 | 5/15/2020 | WO | 00 |
