SE540541E - Process for the treatment of heavy residues, derived from materials of biological origin, and for the production of liquid fuel - Google Patents

Abstract

The present invention relates to a process for treating heavy residues derived from materials of biological origin, wherein said heavy residues are subjected to hydrolysis and purification treatment with subsequent separation of an organic phase and an aqueous phase. The invention also relates to a process for the production of liquid fuel and fuel components, wherein the obtained organic phase is further subjected to catalytic hydrogen treatment.

Description

PROCESS FOR THE TREATMENT OF HEAVY RESIDUES DERIVED FROM MATERIALS OF BIOLOGICAL ORIGIN AND FOR THE PRODUCTION OF LIQUID FUEL FIELD OF THE INVENTION The present invention relates to a process for the treatment of heavy residues derived from materials of biological origin. The invention also relates to a process for the production of liquid fuel and fuel components from heavy residues derived from material of biological origin and raw material comprising material of biological origin, whereby heavy residues derived from material of biological origin are converted into components suitable as raw material in said process. The invention also relates to subjecting heavy residues of biological origin to hydrolysis with subsequent purification to obtain purified components, which are subjected to hydrogen treatment whereby liquid fuels can be obtained.

BACKGROUND OF THE INVENTION Feedstock of biological origin can be converted to liquid fuel by subjecting the feedstock to catalytic hydrotreating with hydrogen gas. The resulting product stream can be further fractionated by e.g. distillation to obtain liquid fuel and liquid fuel components.

Raw materials of biological origin usually contain various impurities. The raw material may be purified and/or pretreated before being fed into the process, whereby the purified raw material and heavy residues and impurities are obtained. Several alternative methods are available to perform the purification and/or pretreatment of the raw material of biological origin.

An example of a raw material of biological origin is pine oil, which is a significant by-product of the sulfate process (Kraft process) for pulp production. In the sulfate process, resin acids and fatty acids, which occur for example in pine wood as free acids or their esters, are saponified with boiling liquid (black liquor) to their corresponding sodium salt. These salts, or soaps thereof, together with some neutral components are dissolved or suspended in the used cooking liquid. This liquid is later concentrated and the soaps and neutral components are separated as tall oil slag. Most Kraft factories that process conifers use pine oil soap. This soap is usually acidified to produce crude tall oil (CTO).

Raw pine oil can be burned to generate heat and electricity, or it can be further used, for example, by companies that refine pine oil. Crude pine oil can also be converted into hydrocarbons suitable as liquid fuel and the like.

Companies that refine tall oil usually separate certain groups of compounds (eg free resin acids and fatty acids) from tall oil or crude tall oil, resulting in a residual product called tall oil pitch (TOP). In pine oil fractionation, the proportion of the pine oil pitch in the crude pine oil is usually around 30-35%. Pine oil pitch consists mainly of neutral components, usually around 70-90%, but generally also contains resin acids, usually around 10-20%, and residual fatty acids, usually around 2-5%, all percentages being pulp. Neutral components mainly consist of sterols, stanols, sterol/stanol esters, polymeric acids, polymeric neutrals, dimers, trimers and lignin derivatives. Some resin oxygen esters can also occur in pine oil pitch. Usually, pine oil pitch is burned in lime kilns or in cogeneration plants.

In liquid fuel production, crude pine oil can be pretreated to remove excess metals and high boiling point components (>600°C) before being subjected to catalytic hydrogenation. Crude pine oil can be subjected to deresining, where crude pine oil is evaporated. During de-resining, a significant amount of valuable raw material is lost as heavy residues (pitch). Said pitch is usually burned for energy production.

The amount of heavy residues formed when raw pine oil evaporates can be approx. 5-15% calculated on the basis of the raw material. The heavy residues (pitch) removed still contain neutral components, such as esters of sterols and stanols, resin acids and fatty acids, and some of the acids may be chemically bound to the neutral components. The heavy residues are generally led to incineration.

In order to maximize the utilization of heavy residues derived from materials of biological origin, such as pine oil pitch and the heavy residues and pitch fractions derived from pine oil, which are obtained e.g. during de-resining, evaporation and distillation, there is a need to convert, in particular, neutral components found in the heavy residues, pitch and pitch fractions, into components such as sterols, stanols, fatty acids, resin acids, esters and alcohols.

SUMMARY OF THE INVENTION According to one embodiment, the invention relates to a process for treating heavy residues derived from material of biological origin, wherein a mixture formed from raw material comprising at least one heavy residue derived from material of biological origin and an aqueous substance is subjected to for hydrolysis to produce a hydrolyzed mixture, with subsequent separation of the hydrolyzed mixture into an organic phase and an aqueous phase, wherein the organic phase and at least one raw material comprising material of biological origin is subjected to at least one purification treatment to obtain a purified product.

The process for treating heavy residues derived from materials of biological origin according to the present invention offers purified products or components useful as raw materials for chemical processing.

According to another embodiment, the present invention also relates to a process for the production of liquid fuel and fuel components, wherein a mixture formed from raw material comprising at least one heavy residue derived from material of biological origin and an aqueous substance is subjected to hydrolysis to produce a hydrolyzed product, with subsequent separation of the hydrolyzed mixture into an organic phase and an aqueous phase, subjecting the organic phase and raw material comprising material of biological origin to at least one purification treatment to obtain a purified product and then subjecting the purified product to catalytic hydrogenation whereby liquid fuel or its components are obtained.

In addition, the process for producing liquid fuel or fuel components according to the invention in question offers bio-oils, which can be used, for example, as fuels and fuel components.

An aim of the invention is thus to offer a process to efficiently and advantageously convert potential materials found in heavy residues originating from materials of biological origin, to produce useful starting materials and partial raw materials for chemical processing, in particular in the production of liquid fuel, whereby the amount of material that is usually thrown away or burned can be reduced.

Another aim of the invention is to offer a process for the production of liquid fuel and fuel components.

A further object of the invention is to offer bio-oils based on heavy residues derived from materials of biological origin, and on renewable starting materials, for use as liquid fuels or fuel components.

DEFINITIONS The term "hydrotreating" refers here to the catalytic treatment of organic material using molecular hydrogen.

The expression "neutral components" or "neutral fraction" or "neutral materials", which are often also called "unsaponifiables", refers here to all neutral organic components in heavy fractions or residues obtained when materials of biological origin are treated or refined. Examples of the mentioned materials are pine oil pitch and pine oil material. Examples of neutral components found in, for example, tallow pitch include sterols, stanols, sterol and stanol esters, polymeric acids, polymeric neutral substances, dimers, trimers, lignin derivatives, resin acids and fatty acids and esters thereof.

The term "pine oil" or "crude pine oil" (CTO) here refers to a product consisting essentially of both saturated and unsaturated oxygen-containing organic compounds such as resins, unsaponifiables, sterols, resin acids (primarily abietic acid and its isomers), fatty acids ( primarily linoleic acid, palmitic acid, oleic acid and linolenic acid), fatty alcohols, sterols, other alkyl hydrocarbon derivatives, as well as inorganic impurities (alkali metal compounds, sulphur, silicon, phosphorus, calcium and iron compounds). Pine oil also includes soap oil.

Pine oil or crude pine oil refers to processed mixtures of naturally occurring compounds extracted from woods such as birch, pine, spruce and aspen. It is usually obtained by acidifying crude tall oil soap from pulping through the sulfate process and the sulfite process in papermaking. The treatment and cooking of the wood causes the breakdown of the triglyceride structures and thus pine oil and crude pine oil do not contain significant amounts of triglycerides. The composition of pine oil and crude pine oil varies depending on the type of wood.

The term "liquid fuel" here refers to fractions or parts or mixtures of hydrocarbons with distillation curves standardized for fuels, such as for diesel fuel (middle distillate from 160 to 380°C, EN 590), gasoline (150 to 210°C, EN 228), jet fuel (160 to 300°C, ASTM D-1655 jet fuel), kerosene, naphtha, etc.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic flow diagram representing one embodiment of the liquid fuel production process.

Figure 2 shows distillation curves for pitch before and after treatment.

DETAILED DESCRIPTION OF THE INVENTION The invention is based on the idea that one could effectively utilize the valuable components found in heavy residues derived from materials of biological origin. Examples of such residues are pine oil pitch, fractions of pine oil pitch and heavy residues and/or fractions obtained from resin removal, evaporation and distillation of pine oil material, crude pine oil and the like. It was discovered that said valuable components can be converted into starting materials and sub-raw materials suitable for chemical processing such as catalytic hydrotreating to provide liquid fuel or fuel components. The yield of liquid fuel or components of liquid fuel can be increased and the amount of residual material carried forward to incineration can be significantly reduced.

In the process according to the invention, heavy residues originating from materials of biological origin are subjected to hydrolysis, where primarily neutral components found in said heavy residues are hydrolyzed to produce valuable components. When said heavy residues originate from pine oil material, compounds such as resin acids, fatty acids, sterols and stanols can be obtained. Fractions comprising valuable components can be separated and then passed on to at least one purification treatment together with raw material comprising material of biological origin to obtain purified products.

The product obtained from said purification treatment can be passed on to further chemical treatment. The purified product is suitably subjected to catalytic hydrogen treatment to obtain liquid fuel or fuel components.

If heavy residues derived from pine oil or pine oil material are used, surprisingly large amounts of valuable compounds can be separated for further treatment from said heavy residues. It has been discovered that even 50% by weight of the heavy residues, such as tall oil pitch or pitch fractions, can be converted and/or separated and conveniently used effectively, for example, in the catalytic hydrogen treatment. Above all, fatty acids and resin acids, which are chemically bound to neutral components in the pitch, can be released by mild hydrolysis with subsequent purification, such as evaporation treatment, and then they can be passed on to catalytic hydrogen treatment.

The process according to the invention in question, for the treatment of heavy residues originating from material of biological origin, comprises the steps of a) subjecting a mixture consisting of raw material comprising at least one heavy residue originating from material of biological origin and an aqueous substance to hydrolysis at a temperature from 10 to 280°C and at a pressure from 0 to 70 bar to obtain a hydrolyzed mixture, b) separates the hydrolyzed mixture into an organic phase and an aqueous phase, c) exposes the organic phase and the raw material comprising at least one material of biological origin for at least one purification treatment to obtain a purified product.

Said purified product can be used as raw material in chemical treatment, such as catalytic hydrogen treatment.

The heavy residues suitably originate from pine oil material.

The process according to the invention in question, for the production of liquid fuel or fuel components, comprises steps a) - c) as described above and further steps d) - f).

The process according to the invention in question, for the production of liquid fuel or fuel components, comprises the steps of a) subjecting a mixture formed from raw material comprising at least one heavy residue derived from material of biological origin and an aqueous substance to hydrolysis at a temperature from 10 to 280°C and at a pressure from 0 to 70 bar to obtain a hydrolyzed mixture, b) separates the hydrolyzed mixture into an organic phase and an aqueous phase, c) subjects the organic phase and raw material comprising at least one material of biological origin to at least a purification treatment to obtain a purified product, d) feeding the purified product to a reactor system comprising at least one catalytically active hydrotreating reaction phase wherein said purified product is contacted with at least one hydrotreating catalyst, e) catalytically treating the purified product with hydrogen in the reactor system to achieve oxygen decomposition by hydrogen treatment, hydreria ng, isomerization, and cracking of components present in the purified product to produce a hydrotreating product, and f) recovering at least a fraction of the hydrotreating product as liquid fuel or fuel component.

Heavy residues The heavy residues can originate from any material of biological origin, and it can be obtained by any evaporation treatment including de-resining and distillation of said material. The heavy residues suitably originate from pine oil material. Said heavy residues can be selected from tall oil pitch (TOP, which can be obtained, for example, from crude pine oil), heavy residues and pitch fractions obtained from any evaporation treatments including deresining and distillation of tall oil material, and heavy evaporation residues obtained from purification treatment carried out as evaporation treatment in the process according to the invention, and combinations thereof.

The pine oil materials include one or more pine oil components, pine oil derivatives and combinations thereof, including crude pine oil, tall oil fatty acids, tall oil soap, etc. Tall oil materials mainly refer to a by-product of the sulfate process for pulping wood, such as conifers, birch, aspen, etc. Tall oil materials are usually a mixture of fatty acids, resin acids, neutral components and turpentine components derived from wood, such as conifers. The turpentine components of pine oil consist mainly of C10H16 terpenes.

Hydrolysis According to the invention in question, heavy residues, and above all organic compounds, such as neutral components therein, are subjected to hydrolysis whereby phases comprising valuable components can be separated and then passed on to at least one purification treatment. If the heavy residues originate from tall oil material, phases including, for example, resin acids, fatty acids, sterols and stanols can be separated.

In step a) of the process according to the invention, a mixture formed from raw material comprising at least one heavy residue originating from material of biological origin and an aqueous substance is subjected to hydrolysis at a temperature between 10 and 280 °C and at a pressure between 0 and 70 bar to obtain a hydrolyzed mixture.

The aqueous substance is selected from water, and mixtures of water and at least one alkali metal hydroxide and at least one C1-C4 alcohol.

The water-based substance is used in volume ratios from 1:20 to 20:1 in relation to the raw material.

If only water is used as the aqueous substance, the volume ratio between water and raw material is suitably from 1:2 to 10:1. Tap water and suitably demineralized or deionized water can be used.

The alkali metal hydroxide is suitably NaOH or KOH. The amount of alkali metal hydroxide in the mixture is 1-20% by weight, preferably 5-15% by weight. The C1-C4 alcohol is suitably methanol, ethanol, butanol or a combination of these. The amount of alcohol in the mixture varies between 50-96% by volume, preferably 80-95% by volume. The amount of alcohol needed is estimated on the basis of the amount of heavy residues. In particular, it is suitable to use methanol obtained as a by-product during pulp production.

The hydrolysis can be carried out in the presence of a catalyst comprising at least one cationic amine compound. The hydrolysis reaction can be improved with said catalysts, especially in cases where water is used as a water-based substance. If amine catalyst is used, the volume ratio between water and raw material is usually from 1:20 to 10:5, preferably 1:15 to 1:10.

Suitable cationic amine compounds are water-soluble cationic amine soaps comprising primary, secondary and tertiary mono- and polyamines, such as aliphatic, including cycloaliphatic, mono- and polyamines and mixtures thereof. Said amine catalysts are used in amounts of 0.001 - 0.5% by weight, calculated on the basis of the raw material, preferably 0.01 - 0.2%.

The amine compounds can contain up to 20, preferably more than 6 carbon atoms in their structural formula. Examples of suitable amines are isopropylamine, n-propylamine, diisopropylamine, n-butylamine, di-n-butylamine, tri-n-butylamine, triethylamine, cyclohexylamine, ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, etc.; heterocyclic N-containing mono- and polyamines, for example, morpholine, N-methyl-morpholine, 4(2-aminoethoxy)ethylmorpholine, 2-(4-morpholinylethoxy)ethanol, bis-2-(4-morpholinyl)ethyl ether, piperazine, N-aminoethyl piperazine, N-hydroxy-ethyl piperazine, pyridazine, pyrrole, pyrrolidine, pyridine, piperadine, pyrimidine, pyridazine, etc. Long chain fatty acid amines are also useful, such as primary amines from cocoa fatty acids, secondary dilaurylamine and tertiary N,N-dimethyldodecylamine.

Suitable quaternary cationic amine soaps include aliphatic amines and arylamines having from 10 to 22 carbon atoms, such as quaternary dodecylphenolamine soaps, cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, dodecyltrimethylammonium chloride, and nonyltrimethylammonium chloride.

The mixture of raw material comprising at least one heavy residue derived from material of biological origin and the aqueous substance can be formed by means of any mixing method and device with which vigorous stirring or shaking can be achieved. Conveniently, the mixing is performed with a homogenizer, with a dispersing pump, or a "high-shear" mixer. The mixing can be carried out before or simultaneously with the hydrolysis.

If the mixing of the raw material with the water-based substance is carried out before the hydrolysis, a temperature of 5 - 120°C is used, preferably 70 - 120°C. If the water-based substance is water, a temperature of 5 - 100°C is used, preferably 70 - 99°C.

The mixing/homogenization and hydrolysis can be performed in the same vessel, or the mixing or homogenization can be performed in a separate mixing/homogenization vessel or channel and the hydrolysis can be performed in a separate hydrolysis vessel or reactor.

If necessary, the mixed/homogenized mixture can be heated before the hydrolysis step, preferably with the help of a heat exchanger or the like. dyl.

The hydrolysis of the mixture is carried out at a temperature of 10 - 280°C, preferably 60 - 280°C. The hydrolysis of the mixture is carried out at a pressure of 0 - 70 bar, preferably 0.1 - 70 bar. A hydrolyzed mixture is obtained.

If only water is used as the aqueous substance, the hydrolysis is conveniently carried out at a temperature of 220 - 280°C. A pressure of 25 - 70 bar is conveniently used. The hydrolysis is conveniently carried out for 30 min to 10 hours.

When an amine catalyst is used, together with water as the aqueous substance, the hydrolysis is suitably carried out at a temperature of 80 - 180°C, preferably 80 - 125°C. The pressure is from 0 to 5 bar, preferably from 0.1 to 1.5 bar. The hydrolysis is suitably carried out for 10 min to 3 hours.

When the aqueous substance comprises at least one alkali metal hydroxide and at least one alcohol, the hydrolysis of the mixture is carried out at a temperature of 60 - 200°C, preferably 100 - 200°C. A pressure of 1 - 30 bar, preferably 1-3 bar is used. The hydrolysis is suitably carried out from 30 min to 10 hours, suitably from 45 min to 2 hours.

The pH of the hydrolyzed mixture is suitably adjusted to a value of 2-3 with an acid selected from strong acids, such as H 2 SO 4 , HNO 3 etc. Suitably, H2SO4 is used. When only water is used as the aqueous substance, without a catalyst, the pH value of the hydrolyzed mixture is suitably adjusted to 5.8 - 6.9 if necessary.

If necessary, the hydrolyzed mixture, after an optional pH adjustment, can be cooled before the subsequent separation step, preferably with the help of heat exchangers or the like. dyl. Conveniently, the hydrolyzed mixture is cooled to a temperature below 100°C, preferably to 65-95°C.

Separation The hydrolysed and optionally cooled mixture is separated at a temperature below 100°C, preferably at 65 - 95°C into an organic phase and an aqueous phase. The separation can be carried out with any known separation aid. The organic phase usually includes non-water soluble compounds, volatile organic compounds, free acids, alcohols and unsaponifiable components and the aqueous phase usually includes water soluble compounds, alkali metal salts and the like. The water phase is preferably directed further to waste water treatment.

The separation can be performed by any suitable separation aid, such as hydrodynamic separation, gravimetric separation, and coalescence separation. Conveniently, decanting methods and equipment can be used.

Purification The separated organic phase and the raw material comprising at least one material of biological origin is led to at least one purification treatment to obtain a purified product.

The material of biological origin is selected from the group consisting of a) vegetable fats, vegetable oils, vegetable waxes; animal fats, animal oils, animal waxes, fish fats, fish oils, fish waxes, and b) recycled fats and oils of food grade, and fats, oils and waxes obtained by genetic engineering, and c) fats, oils and waxes obtained from algae, molds, yeasts , fungi and/or other microorganisms capable of producing said compounds; and d) mixtures of said biological raw materials.

According to an embodiment of the invention, the material of biological origin is selected from the group consisting of fish oils such as sturgeon oil, salmon oil, herring oil, tuna oil, anchovy oil, sardine oil, and mackerel oil; vegetable oils such as rapeseed oil, rapeseed oil, canola oil, pine oil, crude pine oil, sunflower seed oil, soybean oil, corn oil, hemp oil, linseed oil, olive oil, cottonseed oil, mustard oil, palm oil, peanut oil, castor oil, Jatropa seed oil, Pongamia pinnata seed oil, palm kernel oil, and coconut oil; and animal fats such as lard, tallow, rendered tallow and tallow, and food grade waste and waste fats and oils, as well as genetically engineered fats, waxes and oils; animal waxes such as beeswax, china wax (insect wax), shellac wax, and lanolin (wool wax); plant waxes such as carnauba palm wax, Ouricury palm wax, jojoba seed oil, candelilla wax, esparto wax, japan wax, rice bran oil, terpenes, terpineols and triglycerides or mixtures thereof.

According to an embodiment of the invention, the material of biological origin comprises non-edible vegetable oils or components thereof or derivatives thereof, for example obtained as by-products from the forest industry. According to one embodiment of the invention, material of biological origin consists of pine oil material. Tall oil materials include tall oil components, tall oil derivatives and any combination thereof, including crude tall oil (CTO), tall tall fatty acid (TOFA), etc. The purification treatment is selected from bleaching, gum/resin removal, washing, ion exchange and evaporation treatments and any combination thereof.

The purified product obtained by the said purification method(s) can be passed on to further chemical treatment, preferably to catalytic hydrogen treatment for obtaining liquid fuel or fuel components.

According to one embodiment, removal of rubber/resin can be used for purification, primarily to remove metal complexes. The removal of rubber/resin can be carried out by washing the organic phase and the raw material comprising at least one material of biological origin, preferably at 90-105°C, 300-500 kPa, with an acid, such as H3PO4, followed by treatment with a base, such as NaOH and soft water and separates the gum resins formed. A large proportion of the metal components can be removed in this removal step.

According to another embodiment, bleaching can be used for purification. In the bleaching, the organic phase and the raw material comprising at least one material of biological origin can be heated and mixed with natural or acid-activated bleaching clay. Bleaching can remove various kinds of traces of impurities and reduce the tendency to oxidation. Bleaching can be carried out under reduced pressure to minimize possible oxidation.

According to one embodiment, the organic phase and the raw material comprising at least one material of biological origin can be subjected to washing with water or a weak acid solution.

According to one embodiment, the organic phase and the raw material comprising at least one material of biological origin can be subjected to ion exchange treatment.

According to one embodiment, the organic phase and the raw material comprising at least one material of biological origin can be subjected to evaporation treatment. In the evaporation treatment, the organic phase and the raw material comprising at least one material of biological origin are fed to an evaporation unit comprising at least three evaporators, where the organic phase and the raw material comprising at least one material of biological origin are subjected to evaporation treatment to obtain a purified product (an effluent, effluent, comprising the purified organic phase) and a heavy evaporation residue. The resulting runny evaporation residue is at least partially returned to the raw material comprising heavy residues.

At the input to the evaporation unit in the evaporation treatment, the weight ratio of the organic phase to the material of biological origin is from 0.1:99.9 to 20:80, preferably 0.2:99.8 to 15:85, especially preferably from 0.2: 99.8 to 10:90. At the feed to the evaporation unit, preferably no more than 15% by weight of the raw material consists of the recycled heavy evaporation residues obtained in the process.

By evaporation (evaporation) is meant here any suitable separation method for separating two or more components from each other, such as gases from liquid, which separation method is based on the utilization of differences in the vapor pressure of the components. Examples of such separation methods are evaporation, flashing and distillation. Examples of suitable evaporation methods are those that utilize thin film evaporation technology. The evaporators can thus be selected from the group consisting of thin film evaporators, falling film evaporators, short path evaporators, plate molecular stills and any other evaporators that use thin film evaporation technology. The evaporation unit may comprise one, two, three, four or more evaporators, which may be either of the same type or of a different type and are independently selected from among the suitable separation methods presented above. The evaporation treatment is carried out in an evaporation unit comprising evaporators arranged in series.

The evaporation in the process according to the invention comprises three, four or more evaporation steps.

Water, metals and solids, for example lignin, compounds including for example metals, which mainly consist of Na, Fe, P, Si, sulfates such as Na2SO4 and H2SO4 are removed in the evaporation treatment.

In the embodiment where the evaporation is accomplished in three stages, i.e. where the evaporation unit comprises three evaporators, water and light components are first evaporated from the raw material in the first evaporation stage to make the following evaporation stage more efficient. In the second and third evaporation stages, the residual fraction containing pitch is minimized by evaporating the liquid product from the first evaporation stage. The advantage of using a three-stage evaporation unit is that the second evaporation stage can be a small and inexpensive evaporator that removes light components from the material. The subsequent third evaporation step can also be smaller and more favorable than the second step in two-stage evaporation. The heavy fraction from the second evaporation stage is passed to the third evaporator, from which the heavy evaporation residue containing mainly heavy polymeric components and pitch is recycled to hydrolysis and the effluent, which usually contains mainly fatty acids, is obtained as the purified product, which can be passed on to chemical treatment, such as catalytic hydrotreating.

According to an embodiment of the invention, the evaporation is thus carried out in three stages by feeding the organic phase (obtained from hydrolysis) and raw material comprising at least one material of biological origin to an evaporation unit comprising three evaporators. In the first stage of three-stage evaporation, water and light components are removed at a temperature of 50 - 250°C and a pressure of 5 - 100 mbar, preferably at a temperature of 120 - 200°C and a pressure of 10 - 55 mbar. The evaporator is suitably a thin film evaporator or a falling film evaporator. In the second step, the liquid product from the first evaporation step is evaporated at a temperature of 180 - 350°C and a pressure of 0.1 - 40 mbar, preferably at a temperature of 200 - 270°C and a pressure of 0.1 - 20 mbar . The evaporator is suitably a plate molecular distillation apparatus or a thin film evaporator. Particularly suitably, the evaporator is a thin film evaporator. The distillate from the second stage is used as purified material and the liquid fraction is directed to a third evaporation stage. In the third step, the liquid product from the second evaporation step is evaporated at a temperature of 200 - 450°C and a pressure of 0 - 50 mbar, preferably at a temperature of 300 - 390°C and a pressure of 0.01 - 10 mbar. The evaporator is suitably a short path evaporator or a thin film evaporator. The heavy evaporation residue from the third stage is returned to the feed to the hydrolysis and the effluent (the purified material recovered in the third stage) is combined with the purified material from the second stage to obtain the purified product. The purified product can be used as a feedstock for catalytic hydrogenation.

According to another embodiment of the invention, the evaporation is carried out in four stages by feeding the organic phase from hydrolysis and the raw material comprising at least one material of biological origin to an evaporation unit comprising four evaporators. In four-stage evaporation, the organic phase and the raw material comprising material of biological origin are evaporated in a first evaporator to produce a first fraction comprising water and light components, and a second fraction comprising heavy components and residues. The second fraction is evaporated in a second evaporator to produce a third fraction comprising water and light low boiling compounds and a fourth fraction comprising heavy components and residues. The fourth fraction is evaporated in a third evaporator to produce a fifth fraction comprising mainly fatty acids and a sixth fraction comprising heavy components and residues. The sixth fraction is evaporated in a fourth evaporator to produce a seventh fraction comprising mainly fatty acids and an eighth fraction comprising heavy evaporation residue, which is recycled in the feed to hydrolysis. The fifth and seventh fractions are combined and used as the purified product, which can be used as a feedstock for catalytic hydrotreating.

In the four-stage evaporation, the first evaporator can be a falling film evaporator (tube evaporator with falling film) or a flat molecular distillation apparatus or a thin film evaporator, preferably a falling film evaporator (FFE) or a flat molecular distillation apparatus is used, especially preferably a falling film evaporator is used. The raw material (the organic phase and the raw material comprising material of biological origin) is evaporated in the first evaporator at a temperature of 80 to 150°C, preferably from 90 to 120°C. The evaporation is carried out at a pressure of from 40 to 80 mbar, preferably from 45 to 65 mbar. A first fraction comprising water and some other light components is separated and the second fraction comprising the heavier components and residues, such as fatty acids, resin acids, neutral substances etc. is led further to a second evaporator. A falling film evaporator effectively removes a large fraction of the water present in the feedstock, typically more than 50% by weight; the second fraction containing the remaining components is passed on to the second evaporator.

The second evaporator is a thin film evaporator or a short path evaporator or a plate molecular distillation apparatus, preferably a thin film evaporator is used. The second evaporator operates at a temperature from 180 to 250°C, preferably from 190 to 220°C. A pressure of 40 to 80 mbar, preferably from 45 to 65 mbar is used. A third fraction containing water and light hydrocarbon components with a low boiling point, said fraction having a boiling point of 100 - 210 °C, preferably 100 - 170 °C at normal pressure, is removed and the fourth fraction in liquid form is led to the third evaporator. When crude tall oil (CTO) is used as material of biological origin, Crude Sulfate Turpentine (CST) is removed in the third fraction together with water. Preferably, the first and the second evaporator operate at the same pressure. Ideally, the same pressure vessel or pressure line is used. The liquid fraction from the second evaporator is led to a third evaporator. A thin film evaporator or a plate molecular distillation apparatus or a short path evaporator can be used, preferably the third evaporator is a short path evaporator. The third evaporator usually operates at a temperature of 200 to 350°C, preferably from 250 to 300°C. A pressure of 0.01 to 50 mbar, preferably 0.5 to 10 mbar, more preferably 1 to 5 mbar and above all 2 to 3 mbar is used in the third evaporator. A fifth fraction (distillate) usually comprising mainly (more than 50% by weight) fatty acids is separated and conveniently fed to a reactor feed tank and the sixth fraction (liquid phase) is led to a fourth evaporator.

The fourth evaporator can be a short path evaporator or a plate molecular distillation apparatus, preferably a short path evaporator is used. Typical working conditions include a temperature of 250 to 400°C, preferably from 290 to 360°C. A pressure of 0.01 to 10 mbar, preferably 0.01 to 5 mbar, more preferably 0.1 to 2 mbar is used. From the fourth evaporator, the seventh fraction (the distillate) is obtained and combined with the distillate fraction obtained from the third evaporator to obtain a purified product, which can be used as a feedstock for catalytic hydrogenation and it can be fed to a hydrogenation reactor feed tank. The eighth fraction (the heavy evaporation residue, very viscous fraction), the amount of which is usually about 5% of the original raw material, is at least partially returned to the raw material comprising heavy residues.

According to one embodiment, the purification treatment is an evaporation treatment comprising three or four evaporation steps and heavy residues obtained from any of the third or fourth evaporation steps are returned to the raw material comprising at least one heavy residue derived from material of biological origin.

According to an embodiment of the invention, the organic phase from the hydrolysis and the material of biological origin can optionally be subjected to a further flash-up step before the evaporation treatment, before feeding to the first evaporator. Flashing can be carried out by any suitable method, for example using heat exchanger expansion vessels where volatile components are released.

An advantage of purification with a three- or four- or multi-stage evaporation is that the boiling can be carried out in a more controlled way, because light components with a low boiling point, in other words components whose boiling point is 150 - 210°C, preferably 150 - 170°C , at normal pressure, does not cause as much "carry over", i.e. migration of components having a boiling point at the higher end of the aforementioned ranges as well as impurities to the vapor in the subsequent evaporation step. The light components can, if desired, be led to hydrogen treatment or further refined in another process or reused.

Catalytic hydrogen treatment According to an embodiment of the invention, the purified product is led from the purification treatment to catalytic hydrogen treatment.

Said catalytic hydrogenation comprises the steps where d) feeding the purified product into a reactor system comprising at least one catalytically active hydrogenation reaction phase, wherein said purified product is brought into contact with at least one hydrogenation catalyst. e) catalytically treats the purified product with hydrogen in the reactor system to achieve oxygen splitting by hydrotreating, hydrogenation, isomerization and cracking of components present in the purified product to obtain a hydrotreating product, and f) recovers at least a fraction of the hydrotreating product as liquid fuel or fuel component.

According to an embodiment of the invention in question, there can optionally be further purification between the purification treatment and the hydrogen treatment. The further purification can be realized by using a guard bed, i.e. a separate pretreatment bed before the hydrogen treatment. The additional purification can also be realized by a purification bed or section located in the vicinity of the hydrotreating reactor.

The process according to the invention in question, for the production of liquid fuel or fuel components optionally includes treatment of the purified product in one or more protective beds. The one guard bed or the several guard beds can be arranged either in separate guard bed units and/or in the hydrotreating reactor. The task of the protective bed is to act against harmful substances in the feed. The protective bed is usually activated gamma alumina or a commercially available purification catalyst. The guard bed material may also include catalyst materials capable of catalyzing hydrotreating reactions. The catalyst material may comprise the same material used in the hydrotreating reactor. The guard bed or guard bed units can retain both solid and solvated impurities from the feedstock of biological origin, such as silicone-based antifoams from a tall oil process and harmful chemicals. The protective bed and/or protective bed units may be heated, unheated, pressurized or non-pressurized, with added hydrogen gas or without hydrogen gas. Suitably, the protective bed and/or protective bed units are heated and non-pressurized.

There are essentially two types of protective beds, these are active and inactive protective beds. The active guard beds take part in the purification of the feedstock and change the chemical composition of the feedstock and they can be located either in separate guard bed units or inside the hydrotreating reactor itself. In one embodiment, the active protective bed comprises only gamma alumina. In another embodiment, the active protective bed comprises catalyst materials capable of catalyzing hydrotreating reactions, such as a catalyst containing Group VI and/or VIII metals or mixtures or combinations thereof, which catalyst is capable of converting biological feedstock to fuel components. In another embodiment, the active guard bed comprises a NiW catalyst or a mixture or combination of several thin layers or beds of NiW and NiMo catalysts on a support selected from Al 2 O 3 , zeolite, zeolite-AhCb and AhCte-SiCte.

The inactive protective beds only take part in the purification of the raw material. These protective beds suitably comprise passive or inert materials. The number of separate shelter beds can be increased, which means that there are one or more shelter beds on standby in parallel or in series with the shelter bed(s) in use.

The process according to the present invention comprises hydrotreating the purified product in the presence of at least one catalyst to produce a mixture of fuel components. The hydrogen treatment according to the invention can be carried out in one, two, three or more steps.

According to one embodiment of the invention in question, the hydrogen treatment is carried out in one step. The catalyst is a catalyst capable of effecting oxygen cracking through hydrotreating, hydrogenation, isomerization, ring opening and cracking of the purified biological material to form a mixture of fuel components. In this embodiment, the catalyst is selected so that it hydrogenates double bonds in the purified biological material that is fed to the hydrogen treatment. The catalyst removes heteroatoms from molecules in the raw material, mainly oxygen, through hydrogenation. The catalyst is capable of hydrogenating olefin bonds of the compounds in the feedstock, of opening at least one of bicyclic rings, and of cracking side chains of hydrocarbon chains. In other words, the hydrocarbons are hydrogenated, isomerized and/or cracked in a single step. The cracking/isomerization is controlled by process variables, such as pressure and/or temperature, and by the properties of the catalyst, for example by controlling its acidity. At the same time, the sulfur compounds are reduced to hydrogen sulfide. The catalyst contained in the hydrotreating reactor is selected from catalysts containing metals from groups VI and/or VII of the periodic table or mixtures or combinations thereof, which catalyst is capable of converting biological feedstock to fuel components in a single step. In a suitable embodiment of the invention, the catalyst comprises NiW, usually on a support selected from Al 2 O 3 , zeolite, zeolite-AhCb, and AhCb-SiCb. In a further suitable embodiment of the invention, the catalyst comprises NiW on an AhCb support.

In yet another embodiment of the invention where the hydrogen treatment is carried out in one step, the catalyst is a mixture or a combination of a NiW catalyst with an additional catalyst. Said additional catalyst may be selected from any catalyst containing metals from groups VI and/or VIII of the periodic table, such as Ni, Co, Mo, Pt, Pd, or mixtures or combinations thereof, such as NiMo and CO, usually on a support which is chosen from AI2O3, zeolite, zeolite-AI2O3 or AhCb-SiCb. In a suitable embodiment, the additional catalyst is NiMo on an AhCb support. In a suitable embodiment of the invention, the catalyst is a combination or a mixture or a combination of several thin layers or beds of NiMo and NiW catalysts.

According to another embodiment, the hydrogen treatment is carried out in two stages. In the first step, fatty acids in the raw material of biological origin are converted to n-paraffins, and in the second step, the obtained n-paraffins are isomerized and/or cracked. In the first step, a catalyst is used which has a suitable metal, such as metals from group VIII and/or VIB of the periodic table can be used. Suitable catalysts are supported Pt, Pd, NiMo or CoMo catalysts, on a suitable support, such as Al 2 O 3 and/or SiO 2 . The catalyst used in the isomerization step is, for example, a molecular sieve, which contains as a metal component noble metals from group VIII, such as Pt and/or Pd, or a NiW catalyst on a suitable support, such as Al2O3, zeolite, zeolite-Al2O3 or AhCet-SiCte.

The hydrotreating catalysts used in the invention need organic sulfur to function and maintain their activity. Therefore, extra sulfur is added to the hydrogen treatment step, if the raw material for the hydrogen treatment does not itself contain sulfur or if its sulfur concentration is too low. The extra sulfur can be fed to the hydrotreating step together with the feedstock or it can be fed separately to the hydrotreating step. Additional sulfur may be added to the process in gaseous form, such as hydrogen sulfide, or it may be any material capable of producing hydrogen sulfide in the process, such as organic sulfur compounds, e.g. dimethyl disulfide. The amount of additional sulfur depends on the amount of sulfur present in the raw material. One skilled in the art can determine the amount of sulfur needed without undue burden. Typically, the H2 input/H2S ratio is kept above about 0.0001, preferably above about 0.001.

The catalyst material must be activated before it has an effect and can be used. The activation involves several steps, one of which is to treat the catalyst with an activating sulfur compound, for example dimethyl disulfide. Thus, the activation procedure involves sulfidation of the catalyst. The activation of catalysts is known in the art and thus will not be discussed here in detail.

The catalyst contained in the reactors of the present invention may be in any suitable form. The catalyst used in the invention in question can be diluted with silicon carbide, aluminum oxide, glass beads, less active catalysts and/or inert materials. The catalyst used in the invention in question can also be undiluted. The catalyst can be in a catalyst bed and the bed can be graded by adjusting the activity, particle shape and/or size of the catalyst used. Dilution and grading of the catalyst facilitates the control of the exothermic balance of the reaction.

The hydrotreating can be carried out in any reactor, column, vessel, container, pipe or line suitable for hydrotreating.

The hydrogen treatment is carried out at a temperature range of about 280°C to about 500°C, preferably from about 330°C to about 430°C. The ability to open fused ring structures is also a desired property of the catalyst.

The hydrogen treatment is carried out at a pressure of about 20 to about 200 bar, preferably at a pressure of about 50 to about 200 bar, more preferably at about 70 to about 120 bar.

The feedstock is pumped to the hydrotreating reactor at the desired rate. Mass flow per hour in relation to the mass of the catalyst (weight hourly space velocity, WHSV) for the raw material is usually in the range from about 0.2 to about 2.5, preferably from about 0.3 to 1.5.

The amount of hydrogen gas needed is determined according to the amount of raw material. The appropriate amount of hydrogen can be determined by a person of ordinary skill in the art. Typically, the Fh feed/feed ratio is in the range of from about 350 to 3000 NI/I, preferably from about 500 to 2500 NI/I. (NI = normal liter, Normal litre). According to one embodiment of the invention, the gaseous compounds that are separated from the compounds in liquid form are hydrogen gas, hydrogen sulphide, light fuel gases, essentially hydrocarbons lighter than C5.

The process according to the invention may further include a step for recycling a portion of the liquid hydrocarbon compounds obtained from the separation or fractionation back to the hydrogen treatment.

According to one embodiment of the invention, the obtained liquid fuel or fuel components are a fraction containing gasoline and/or naphtha and a fraction containing middle distillates.

Figure 1 is a schematic diagram of a process for the production of liquid fuels according to an embodiment of the invention. In the first step in this embodiment, raw material 10, comprising at least one heavy residue derived from material of biological origin, heavy evaporation residue 120 and an aqueous substance 20 is fed to a vessel 100, where homogenization is carried out, the homogenized mixture 30 is led to a heat exchanger 101 for heating and after that to hydrolysis reactor 200, where the mixture is hydrolyzed. From hydrolysis reaction 200, the hydrolyzed mixture 31 is led to a heat exchanger 102 for cooling, followed by the cooled mixture 31 being led to a separation vessel 201, where an aqueous phase 40 (containing water-soluble compounds, alkali metal salts and the like) and an organic phase 50 (containing organic compounds and non-water-soluble compounds) are separated. The organic phase 50 and the feedstock containing material of biological origin 60 are led to an evaporation unit 700, to a first evaporator 300, where water and light components are separated and removed as stream 70 and the liquid stream 80 is led to the second evaporator 400. The distillate 90 (usually comprising fatty acids) is passed to the hydrotreater 800 and the liquid stream 110 is passed to the third evaporator 500. The stream 120 with heavy residues from the evaporator 500 is returned to the homogenizer vessel 100 and the effluent 130 is combined with distillate 90, whereby a purified product is obtained, which is passed to the hydrotreater 800, to the hydrotreating reactor 600. The heavy residues 140 are passed to combustion and the hydrotreating product 150 is passed to further fractionation steps if desired.

The following examples illustrate embodiments of the invention in question, as described above, and they are not intended to limit the invention in any way.

Examples Example 1 A mixture of 25 g of pitch (heavy residue stream obtained from evaporation treatment of crude pine oil in three evaporators) and 100 ml of aqueous 0.5 N KOH in ethanol (95%) was formed and the mixture was then hydrolyzed at about 80°C under NTP in 7 hours. The mixture was cooled and its pH was adjusted to 2-3 with 30% H 2 SO 4 (10 mL). Water (ca. 100 ml) was added to the mixture and it was extracted three times with diethyl ether and hexane 1:1, followed by washing with water. The distillation curve of the pitch used as starting material (highest curve) and after hydrolysis treatment as instructed above (middle curve) is presented in Figure 2, as well as of evaporated (3-stage evaporation) pine oil as a reference (lowest curve). (SimDis/FID, internal standard cholesterol, and sample concentrations were the same in all runs).

Some properties of the pitch (starting material) and treated pitch are presented in table 1 below.

Image available on "Original document" From table 1 it can be seen that the amounts of acids and sterols were increased, whereby increased amounts of valuable starting materials became available for further chemical treatment.

The invention has been described herein with reference to specific embodiments. Nevertheless, it is clear to a person skilled in the art that the process(es) can be varied within what is limited by the patent claims.

Claims (29)

A process for treating heavy residues derived from materials of biological origin, said process comprising the steps of a) exposing a mixture formed of raw material comprising heavy residues derived from materials of biological origin and an aqueous substance for hydrolysis in a temperature from 10 to 280 ° C and at a pressure from 0 to 70 bar to obtain a hydrolysed mixture, b) separates the hydrolysed mixture into an organic phase and an aqueous phase, c) exposes the organic phase and the raw material comprising materials of biological origin of at least one purification treatment to obtain a purified product. A process according to claim 1, wherein the material of biological origin is selected from a group consisting of a) vegetable fats, vegetable oils, plant waxes; animal fats, animal oils, animal waxes, fish fats, fish oils, fish waxes; and (b) recycled fats and oils of food grade, and fats, oils and waxes obtained by genetic engineering; and (c) fats, oils and waxes obtained from algae, mold, yeast , fungi and / or other microorganisms capable of producing said compounds; and d) mixtures of said materials. Process according to claim 1 or 2, wherein the material of biological origin is tall oil material. A process according to any one of claims 1-3, wherein the purification treatment is selected from bleaching, rubber / resin removal, washing, ion exchange and evaporation treatments and any combinations thereof. A process according to any one of claims 1-4, wherein the purification treatment is an evaporation treatment comprising three, four or more evaporation steps. A process according to any one of claims 1-5, wherein the purification treatment is an evaporation treatment comprising three or four more evaporation steps and heavy residues obtained from either of the third and fourth evaporation steps are recovered to the raw material comprising at least one heavy residue derived from materials of biological origin . A process according to any one of claims 1 to 6, wherein the heavy residue is selected from tall oil pitch, heavy residues or pitch fractions obtained from evaporation treatment of tall oil material, and any combinations thereof. A process according to any one of claims 1 to 7, wherein the aqueous substance is selected from water and mixtures of water and at least one alkali metal hydroxide and at least one C 1 -C 4 alcohol. Process according to any one of claims 1-8, wherein the hydrolysis is carried out at a temperature of 220-280 ° C and at a pressure of 25-70 bar and water is used as the aqueous substance. Process according to any one of claims 1-8, wherein the hydrolysis is carried out at a temperature of 60-200 ° C and at a pressure of 1-30 bar, and the aqueous substance is selected from mixtures of water with at least one alkali metal hydroxide and at least one C1 -C4 alcohol. Process according to any one of claims 1-8, wherein the hydrolysis is carried out in the presence of a catalyst comprising a cationic amine compound, at a temperature of 80-180 ° C and a pressure of 0-5 bar, and water is used as the aqueous substance. A process according to any one of claims 1-8, wherein the pH of the hydrolysed mixture is adjusted to the range of 2-3 with an acid. A process according to any one of claims 1 to 12, wherein the evaporator is selected from thin film evaporators, falling film evaporators, short path evaporators, and flat molecule distillation apparatus. A process for the preparation of liquid fuel or fuel components, the process comprising the steps of: a) exposing a mixture formed of raw material comprising heavy residues derived from materials of biological origin and an aqueous substance for hydrolysis at a temperature of from 10 to 280 ° C and at a pressure from 0 to 70 bar to obtain a hydrolysed mixture, b) separates the hydrolysed mixture into an organic phase and an aqueous phase, c) exposes the organic phase and at least one raw material comprising materials of biological origin to at least one purification treatment to obtain a purified product, d) feeding the purified product to a reactor system comprising at least one catalytically active hydrotreating reaction phase wherein said purified product is contacted with at least one hydrotreating catalyst, e) treating the purified product catalytically with hydrogen in the reactor system to provide oxygen cleavage by hydrotreating, hydrogenation, isomerization and cracking components present in the purified product to provide a hydrotreating product, and f) recovering at least a fraction of the hydrotreating product as a liquid fuel or fuel component. The process of claim 14, wherein the material of biological origin is selected from the group consisting of a) vegetable fats, vegetable oils, plant waxes; animal fats, animal oils, animal waxes, fish fats, fish oils, fish waxes; and (b) recycled fats and oils of food grade, and fats, oils and waxes obtained by genetic engineering; and (c) fats, oils and waxes obtained from algae, mold, yeast , fungi and / or other microorganisms capable of producing said compounds; and d) mixtures of said materials. A process according to claim 14 or 15, wherein the material of biological origin is tall oil material. A process according to any one of claims 14-16, wherein the purification treatment is selected from bleaching, rubber / resin removal, washing, ion exchange and evaporation treatments and any combinations thereof. A process according to any one of claims 14 to 17, wherein the purification treatment is an evaporation treatment comprising three, four or more evaporation steps. A process according to any one of claims 14-18, wherein the purification treatment is an evaporation treatment comprising three or four more evaporation steps and heavy residues obtained from either of the third and fourth evaporation steps are recovered to the raw material comprising at least one heavy residue derived from materials of biological origin . Process according to any one of claims 14-19, wherein the heavy residue is selected from tall oil pitch, heavy residues or pitch fractions obtained from evaporation treatment of tall oil material, and any combinations thereof. A process according to any one of claims 14-20, wherein the aqueous substance is selected from water and mixtures of water and at least one alkali metal hydroxide and at least one C1-C4 alcohol. Process according to any one of claims 14-21, wherein the hydrolysis is carried out at a temperature of 220-280 ° C and at a pressure of 25-70 bar and water is used as the aqueous substance. Process according to any one of claims 14-21, wherein the hydrolysis is carried out at a temperature of 60-200 ° C and at a pressure of 1-30 bar, and the aqueous substance is selected from mixtures of water with at least one alkali metal hydroxide and at least one C1 -C4 alcohol. Process according to any one of claims 14-21, wherein the hydrolysis is carried out in the presence of a catalyst comprising a cationic amine compound, at a temperature of 80-180 ° C and a pressure of 0-5 bar, and water is used as the aqueous substance. A process according to any one of claims 14-21, wherein the pH of the hydrolysed mixture is adjusted to the range of 2-3 with an acid. A process according to any one of claims 14 to 25, wherein the evaporator is selected from thin film evaporators, falling film evaporators, short path evaporators, and flat molecule distillation apparatus. A process according to any one of claims 14-26, wherein the hydrotreating is carried out in a single step and the catalyst is a catalyst containing Group VI and / or VIII metals or mixtures or combinations thereof, which catalyst is capable of converting biological raw material into fuel components. Process according to claim 27, characterized in that the catalyst is NiW or a mixture or combination of NiW and NiMo catalysts on a support selected from Al 2 O 3, zeolite, zeolite-AhCb, and AhCte-SiCte. A process according to any one of claims 14-26, wherein the hydrotreating is effected in two steps and the catalyst in the first step is any catalyst containing Group VIII and / or VIB metals in the Periodic Table on a suitable support capable of converting hydrocarbons to n-paraffins and the catalyst in the second step is a catalyst selected from the group Pt, Pd and NiW based on Al 2 O 3, zeolite, zeolite-AhCl 2 or Al 2 O 3 -SiO 2.