FIELD OF THE INVENTION

The present invention relates to the field of renewable heating oils.

BACKGROUND

Environmental awareness and regulations related thereto have driven oil companies to employ more intensively renewable raw material in the manufacture of fuels, such as heating oils. Novel renewable fuels are needed to meet requirements set by regulations and renewable fuel standards.

Currently, it is known that there is heating oil comprising fatty acid methyl esters (FAME) on the market. FAME based fuels are generally called biofuels or traditional biofuels. FAME based fuels are sensitive to aging and have poor cold properties. Heating oil compositions comprising vegetable oil and fossil components rich in aromatic compounds are also known.

Previous attempts for using paraffinic heating oils have failed because of malfunction of the burner. For example WO2008138861 discloses a paraffinic fuel, which needs aromatic or conjugated hydrocarbons to be suitable to be burned in domestic heating appliances.

Renewable heating oil may also be produced using a component produced with a gas-to-liquid (GTL) method. Biomethane or natural gas may be used as raw material.

Hydrogenated vegetable oil (HVO) is a renewable fuel, produced from renewable raw materials, wherein n-paraffins are obtained by hydrogenating vegetable oil fatty acids and triglycerides, after which they may be further converted by using catalysts into branched paraffins (i-paraffins). The manufacturing process of HVO aims to a high yield of saturated hydrocarbons, i.e. alkanes, and avoids formation of aromatic compounds. Double bonds in unsaturated free fatty acids may promote various side reactions, such as oligomerisation, polymerisation, cyclisation, aromatisation and cracking reactions. Methods for producing a renewable hydrogenated fuel are described in publications EP1741768B1 , EP1741767B1 and EP1398364A1 .

DISCLOSURE OF THE INVENTION

The present invention provides a heating oil comprising a fuel component and a colouring agent, the fuel component comprising 1 -100 mass-% of a renewable hydrotreated fuel component having a lower heat value of at least 43,6 MJ/kg. The invention also provides a heating oil blend, comprising heating oil according to the invention and fossil fuel, wherein the amount of fossil fuel is in the range 0- 99 mass-%, preferably in the range 0-15 mass-%, more preferably in the range 5- 10 mass-%.

In the heating oil according to the invention, the renewable fuel component has been produced with a process comprising first hydrogenating and then optionally isomerizing renewable raw-material.

An advantage of the renewable hydrotreated fuel component is that it has a low aromatic content or it may even be free from aromatics. Because of this, it burns cleanly and thus causes less soot formation. The renewable hydrotreated fuel component improves burning properties of heating oil and helps keeping the burning system and chimneys cleaner. The heat value (energy content) of the renewable hydrotreated and optionally isomerized fuel component is better than that of fossil fuel. Further, the renewable hydrotreated fuel component has a higher energy content compared to traditional biofuels. The energy is released during combustion into a usable form, heat.

Heating oil including a renewable hydrotreated fuel component is safe, because of its low amount, or even absence, of aromatic compounds, such as polycyclic aromatic hydrocarbons (PAH compounds), which are toxic and linked to severe health issues and even cancer. The renewable hydrotreated fuel component has an aromatic content even below 1 mass-%. Particularly, in heating oils used in domestic heating systems, the low content or lack of aromatics is beneficial, because by using it exposure to harmful compounds may be avoided for example when filling the fuel tank.

Further, using a heating oil comprising the renewable hydrotreated fuel component in heating systems is in accordance with sustainable development values. Use of fossil fuels in heating can be diminished or the fossil fuel component may be omitted from the heating oil altogether. Use of the heating oil according to the invention enables a heating method that corresponds to modern technical requirements and to possible future bio-obligations.

Further, use of the heating oil according to the invention is particularly advantageous in single-family house and domestic heating because it lacks an unpleasant and distinctive odour typical for heating oils. This makes e.g. maintenance of heating systems and filling of tanks more pleasant. The unpleasant odour of heating oils has previously been masked by using odorants. With the heating oil of the present invention use of odorants can be avoided, but they may be used upon desire. A colouring agent may be comprised in the heating oil according to the invention. By using a colouring agent, the heating oil according to the invention can be distinguished e.g. from fossil heating oils or from fuels meant for vehicles. With the colouring agent fuels and heating oils are generally easy to recognize and they can be distinguished from each other based on the fuel components comprised in them. For example, a certain colouring agent may be used as a mark to indicate a renewable heating oil meeting certain requirements.

Further, or alternatively, a compound to make flame detection in heating systems more effective may be added to the heating oil according to the invention. It was surprisingly found by the inventors that the heating oil according to the invention can be used in conventional domestic heating systems designed to burn fossil fuel without additional components or modifications to the apparatus. This is particularly advantageous in domestic use for those users who want to use renewable fuels in heating but are reluctant to invest in heating systems specifically optimized for renewable heating oils. It is also possible for the user to alternate between using heating oil according to the invention and fossil heating oil, or even using blends thereof. This is particularly beneficial, because cleaning and adjusting of the heating system when changing fuel is thus avoided. The heating oil according to the invention may also be used in conventional heating systems that have been modified.

The heating oil of the present invention may also be fully renewable, wherein the renewable hydrotreated fuel component comprises 100% renewable hydrotreated fuel component. Such heating oil may also be burned in conventional heating systems without mountable or specific modifications thereto.

According to an embodiment the heating oil according to the invention can also be used as an energy source in hybrid heating systems, wherein in addition to fuel heating other forms of heating are employed, such as electric heating, air to air heat pump or solar panels.

Further advantages of the heating oil according to the invention include good stability in long term storage and good cold properties. The cloud point of the heating oil according to the invention is -10 °C or below -10 °C measured according to ASTM D7689:2012. As evidenced by the Examples, the cloud point of the heating oil according to the invention may be even below -30 °C measured according to ASTM D7689:2012, due to which the heating oil according to the invention may be use in very cold or even in arctic conditions. Good cold properties of the heating oil are an important property, because in domestic use and other heating systems heating oil is typically stored in heating oil tanks or containers in varying temperatures for extended time periods. The heating oil tanks may be located at least partially underground or even enterely above ground. Such tanks are exposed to the temperatures of the surrounding air and ground and particularly at cold climate to very low temperatures, wherein the heating oil according to the invention is a particularly advantageous choice. The excellent cold properties of the heating oil according to the invention allow storing the heating oil according to the current invention at low temperatures. BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 Distribution of paraffinic components of 100% renewable hydrotreated heating oil according to the invention (UVL1 and UVL2) and of GTL-fuels (GTL1 , GTL2 and GTL3). CP refers to cloud point. Fig. 2 Detailed distribution of paraffinic components of 100% renewable hydrotreated heating oil according to the invention (UVL) and of a GTL-fuel (GTL1 ).

DETAILED DESCRIPTION OF THE INVENTION When preparing renewable hydrotreated fuel, in the first step of the process fatty acids, triglycerides and other fatty acid derivatives used as raw material are deoxygenated, denitrogenated and desulfurized. In hydrotreatment, oxygen is removed with hydrodeoxygenation (HDO) and carbonyl groups are removed for example by removing oxygen in CO _x form. Further, the treatment includes other catalytic processes with which oxygen is removed from organic oxygen compounds as water, sulphur is removed from organic sulphur compounds in the form of dihydrogen sulphide (H2S), nitrogen is removed from organic nitrogen compounds in the form of ammonia (NH3) and by hydrodenitrogenation (HDN), and halogens, for example chloride, is removed from organic chloride compounds in the form of hydrochloric acid (HCI) and by hydrodechlorination (HDCI).

In the hydrotreating step, the pressure is kept in the range 20-150 bar, preferably in the range 50-100 bar, and the temperature in the range 200- 400 °C, preferably in the range 250- 350 °C, and most preferably in the range 280-340 °C.

In the hydrotreatment and deoxygenation step, known hydrogenation catalysts from Group VIII and/or VIB of the Periodic Table may be used. Preferably, the catalysts are supported Pd, Pt, Ni, NiMo or C0M0 catalysts, and the support is preferably aluminium and/or silicon. Typically, NiMo/A Os and C0M0/AI2O3 catalysts are used. The hydrotreating is optionally followed by isomerisation, such as hydroisomerisation, where branches on the hydrocarbon backbone are formed and i-paraffins are produced. Typically, methyl and ethyl side-chains are formed in the isomerisation step and the degree of isomerisation, e.g. the amount of methyl branches and their distance from each other, can be controlled by reaction conditions, such as temperature and catalyst. Isomerisation causes an improved performance of the product at low temperatures.

In the isomerisation step, the pressure is selected from the range 20-150 bar, preferably from the range 30-100 bar, and the temperature is selected from the range 200-500 °C, preferably from the range 280-400 °C.

In the isomerisation step, an isomerisation catalyst known in the art may be used. A suitable isomerisation catalyst is a molecular sieve and/or metal selected from Group VIII of the Periodic Table and/or carrier. Preferably, the isomerisation catalyst contains SAPO-1 1 or SAPO-41 or ZSM-22 or ZSM-23 or ferrierite, and Pt, Pd, or Ni, and AI2O3 or S1O2. Typical isomerisation catalysts are, for example, Pt/SAPO-1 1/AI ₂ 0 ₃ , Pt/ZSM-22/AI ₂ 0 ₃ , Pt/ZSM-23/AI ₂ 0 ₃ and Pt/SAPO-1 1/S 1O2.

When producing the hydrotreated renewable fuel component hydrotreated, and optionally isomerised vegetable oil (HVO), and/or wood and/or other plant based oil, animal fat, fish fat, fish oil, algae oil, microbial oil or combination thereof, and optionally recyclable waste and/or residue, or a combination thereof may be used as raw material.

Recyclable waste comprises materials such as used cooking oil, free fatty acids, palm oil by-products or side streams of industrial processes, and side streams and waste from vegetable oil processing. According to an embodiment, raw material of the renewable hydrotreated fuel component comprises:

I. one or more free fatty acid distillates, such as palm based free fatty acid distillate and/or soy based free fatty acid distillate;

II. one or more free fatty acid containing bio based raw material, such as crude and refined palm based oil, technical corn oil, tall oil, seed oil, animal fat, waste cooking oil, jatropha curcas oil, fish oil, microbial oil, and/or algae oil;

III. by-products from fatty acid methyl ester and bio based chemicals production and/or oil derived from lignocellulosic biomass; and/or IV. one or more lower molecular weight acids containing bio based raw material such as pyrolysis oil and/or palm oil waste.

For use at particularly cold temperatures, cold properties of the renewable hydrotreated fuel component can be improved by increasing the amount of i- paraffins by controlling the process parameters. In an embodiment, fatty acids or triglycerides of the feedstock are first hydrotreated to n-paraffins, and a part of the n-paraffins are converted to branched chain i-paraffins.

In an embodiment, the hydrocarbons of the renewable hydrotreated fuel component are isomerised.

In an embodiment, the hydrocarbons of the renewable hydrotreated fuel component are isomerised and by isomerisation i-paraffins having side chains are partially formed from n-paraffins. This is beneficial particularly to obtain a heating oil, in which the amount of aromatic or cyclic hydrocarbons does not increase.

In an embodiment, the renewable hydrotreated fuel component of the heating oil comprises at least 70 mass-%, more preferably at least 80 mass-%, most preferably at least 90 mass-% paraffinic hydrocarbons in the range of carbon number C15-C18.

The above distribution of paraffinic components is typical for the renewable hydrotreated fuel component according to the invention. This fuel component may be used in heating oil as a renewable hydrotreated fuel component or as 100 percent as such as heating oil. The renewable hydrotreated fuel component has good cold and storage properties and heat value, and is therefore well suited for use as a heating oil.

The above described narrow distribution of paraffinic hydrocarbons in the range C15-C18 is typical for the heating oil according to the invention and distinguishes it from previous heating oils. For example, heating oils manufactured from natural gas or biogas by GTL process have a much broader distribution of paraffinic hydrocarbons. The hydrocarbon distribution according to the invention is beneficial because heating oil in accordance with it has low volatility, which allows for long term storage of heating oil. In an embodiment, the mass ratio of i-paraffins to n-paraffins of the renewable hydrotreated fuel component is at least 2.2, preferably at least 2.3, at least 3 or at least 4.

In an embodiment, the cloud point of the renewable hydrotreated fuel component is at most -10 °C. In an embodiment, the renewable hydrotreated fuel component comprises less than 1 mass-% aromatics.

In an embodiment, lignocellulose based raw material has been used in the production of the heating oil.

In an embodiment, the heating oil further comprises naphthenic components. In an embodiment, in the renewable hydrotreated fuel component the amount of paraffinic components in the range of carbon number C3-C14 is less than 25 mass-%, such as less than 20 mass-%, less than 10% mass-%, or less than 7 mass-%. In another embodiment, in the renewable hydrotreated fuel component the portion of paraffinic components in the range of carbon number C19-C24 is less than 25 mass-%, such as less than 20 mass-%, less than 10 mass-%, or less than 5 mass-%.

In one embodiment, the heating oil according to the invention comprises a renewable hydrotreated fuel component obtainable from at least one lignocellulosic source. In that kind of embodiment, naphthenic hydrocarbons are compounds obtainable from a lignocellulosic source by converting levulinic acid via carbon-carbon coupling reactions in the presence of an ion exchange resin catalyst, in a thermal treatment, in the presence of a solid metal oxide catalyst system or combination thereof forming levulinic acid dimers and/or oligomers, as described inter alia in publication EP3050867. The solid metal oxide catalyst system may comprise a first metal oxide and a second metal oxide. An increase of the optional naphthenic components increases the density of the renewable hydrotreated fuel component.

In an embodiment, at least one lignocellulose based feedstock has been used in manufacturing of the renewable hydrotreated fuel component according to the invention, wherein during the manufacturing oxygen has been removed by hydrodeoxygenation from a feedstock comprising levulinic acid dimers and/or oligomers, followed by distillation. The renewable hydrotreated fuel component wherein at least one lignocellulose based feedstock has been used is a good component of a heating oil blend, because the resulting fuel has a very low cloud point and it can easily be mixed with other fuels.

In an embodiment, wherein, in manufacturing of the renewable hydrotreated fuel component of the heating oil, at least one lignocellulose based feedstock has been used, comprising renewable middle distillate and containing less than 10.0 mass-% aromatics, as determined in accordance with ASTM D2425-04. In another embodiment, wherein, in manufacturing of the renewable hydrotreated fuel component, at least one lignocellulose based feedstock has been used, containing at most 9.5 mass-%, at most 9.3 mass-%, at most 9.0 mass-%, at most 8.0 mass-%, at most 7.0 mass-%, at most 6.0 mass-%, at most 5.0 mass- %, at most 4.0 mass-%, or at most 3.0 mass-% of aromatics, as determined in accordance with ASTM D2425-04. In another embodiment, wherein, in manufacturing of the renewable hydrotreated fuel component of the heating oil, at least one lignocellulose based feedstock has been used, the cloud point is -70°C or lower, -80°C or lower, - 90°C or lower, or -95°C or lower.

In an embodiment the heating oil optionally comprises naphthenic hydrocarbons. A naphthenic hydrocarbon refers to organic compounds that contain one or more saturated cyclic structures. The general formula of naphthene is CnHbn. A naphthenic hydrocarbon may be a fossil hydrocarbon or a hydrocarbon obtainable from lignocellulose based biomass, or a combination thereof.

In an embodiment the amount of the naphthenic component in the renewable carbon treated heating oil according to the invention is in the range 2-90 mass-%, such as 2-50 mass-%, such as 2-30% mass-%, preferably 2-20 mass-%, 3-15 mass-%, or 3-12 mass-%, preferably about 5-10 mass-%. In an embodiment, the renewable hydrotreated fuel component of the heating oil comprises aromatics and/or polyaromatic components, which increases the density of the end product.

In an embodiment, the heating oil according to the invention further comprises a fossil fuel component.

In an embodiment, the heating oil further comprises fatty acid methyl esters (FAME).

It is possible to blend with the renewable hydrotreated fuel component meant for heating purposes aromatic hydrocarbons, naphthenic hydrocarbons, fossil fuel, and/or FAME. In an embodiment, 100 % renewable hydrotreated fuel component is used in heating systems as such, even without blending it with a fossil fuel component and/or another fuel component. A suitable blend may be selected inter alia according to the requirements of the flame detector.

In an embodiment, the colouring agent is a yellow azo dye, such as Solvent Yellow 124 (N-ethyl-N-(2-(1 -isobutoxy etoxy)ethyl)-4-(phenylazo)aniline). Further, one or more other colouring agent may be used, such as red or blue dye.

In another embodiment, there is at least 1 gm/l, preferably 1 -10 mg/l, colouring agent, and most preferably the amount is selected from the range 6-9 mg/l.

In an embodiment, the colouring agent acts also as a flame detection agent. In an embodiment, the heating oil does not include additives, such as pour point or cold flow improvers.

The use of the heating oil according to the invention is simple, because it does not need any special arrangements. The user of the heating oil according to the invention does not need to carry out cleaning, such as rinsing and/or change filters or settings of the heating system when changing from using one heating oil to using another, for example from a fossil heating oil to the renewable hydrotreated heating oil according to the invention. Heating oil according to the invention can also be added into a heating oil tank even when previously used heating oil is still present in the tank. Similarly, other heating oil can be added into the heating oil tank while heating oil according to the invention is still left in the tank. Boilers, such as steam boilers, heaters, fuel-burning apparatuses, and central heating systems are known as heating systems. Burners, furnaces and heaters are used in heating systems. The heating system may be configured to heat liquid, gas or vapour streams, which are used for transferring heat to a site wherein heating is needed.

In an embodiment, heating oil is burned in a burner for heating households, houses, garages, public buildings or industrial spaces.

In an embodiment, the renewable hydrotreated heating oil according to the invention is burned in a device intended or designed for burning, which device is used for burning fossil fuels and/or fossil heating oils.

In an embodiment the renewable hydrotreated heating oil according to the invention is stored in a tank exposed to outdoor temperatures.

Because of the good cold properties of the renewable hydrotreated heating oil, it can be stored even outdoors without a need to heat or insulate the tank. The heating oil may be stored outdoors and conducted through piping to a heating system located inside a house to be burned. The storage tank may be positioned above ground, or partially, or fully, underground. The tank may also be insulated or provided with a heater, particularly if it is desired to use the same tank for heating oils that do not have as good cold properties.

EXAMPLES

The following examples illustrates the present invention. However, the invention is not limited only to the embodiments of these examples.

Samples used

The renewable hydrotreated heating oil used in the examples is specified in Table 1 . Carbon number profiles of the renewable hydrotreated heating oil and GTL were analysed by gas chromatography (GC). The results are shown in Fig. 1 and Fig. 2.

The product properties of the renewable hydrotreated heating oil used in the tests of the examples were tested. The results are shown in Table 1 .

Table 1 . The product properties of 100% renewable hydrotreated heating oil.

Further, heating oil compositions comprising varying amounts of renewable hydrotreated heating oil and a naphthenic component were tested. The results are shown in Table 2. The measurement results of two heating oils comprising renewable hydrotreated heating oil are shown in Table 3.

Table 2. Heating oil compositions.

Portion of renewable Portion of naphthenic Density kg/m ³ Density kg/m ³ hydrotreated heating component, mass-%t (calculated) (measured)

oil, mass-%

0 100 817.1 817.1

90 10 783.4 783.9

95 5 781.6 782.1

100 0 779.7 779.7

Table 3. Measurement results regarding properties of two heating oil compositions comprising 95 mass-% renewable heating oil and 5 mass-% heating oil containing aromatics or 5 mass-% fossil heating oil containing naphthenics.

Combustion experiments

Combustion experiments of 100% renewable hydrotreated heating oil together with its blends with fossil heating oils containing aromatics, heating oils containing naphthenics and FAME were carried out in a domestic heating system. All tested heating oil blends could be used without perturbations for extended periods of time in a heating system designed for burning fossil fuel and/or heating oil. In the test the following heating system was used: boiler ARIMAX E 30 S, 30 kW; burner Oilon Solarheat LJ 10; filter: Danfoss 2.37 kg/h. Test results of the combustion tests are shown in Table 4.

Table 4. Burning results for heating oils. PA1 =fossil heating oil containing aromatics; PA2=10% fossil heating oil containing aromatics + 90% renewable hydrotreated heating oil; PA4=10% renewable heating oil containing naphthenics + 90 % renewable hydrotreated heating oil; PA6 = 10% FAME + 90% renewable hydrotreated heating oil; PA3=5% fossil heating oil containing naphthenics + 95% renewable hydrotreated heating oil; PA7 = 5% fossil heating oil containing aromatics + 95% renewable hydrotreated heating oil; PA8 100% renewable hydrotreated heating oil.

The above examples are used merely to explain some embodiments and the invention is not limited only to these. The present invention can also be used in other similar embodiments or in combinations of different embodiments.

Further, certain features of the invention have been mentioned in connection with some embodiments. These features can be used also in connection with other embodiments.