NO346124B1

NO346124B1 - Method for upgrading waste oil

Info

Publication number: NO346124B1
Application number: NO20191488A
Authority: NO
Inventors: Blanka Toukoniitty; Annika Malm; Ville Paasikallio
Original assignee: Neste Oyj
Priority date: 2018-12-21
Filing date: 2019-12-17
Publication date: 2022-03-07
Also published as: FR3090686B1; DE102019134472A1; NL2024521B1; NO20191488A1; NL2024521A; GB201918872D0; FI20186124A1; DK180401B1; BE1026831A1; GB2580221A; SE543546C2; GB2580221B; DE102019134472B4; SE1951501A1; ES2773398A2; ES2773398B2; ES2773398R1; DK201970775A1; FI128237B; FR3090686A1

Description

METHOD FOR UPGRADING WASTE OIL

Technical Field

The present invention relates to a method for producing fuel components from waste oil, a fuel component obtainable by the method and the use of the fuel component.

Technical background

Mobility and logistics are an essential part of life, economy and society today. To meet the growing energy needs of traffic and transport it is important to seek sustainable fuel solutions. Decarbonizing the transport sector is a major challenge and fossil fuels should slowly be replaced by more sustainable fuels. Liquid fuel has benefits compared to gases and electricity in traffic solutions due to existing infrastructure and fuel logistics. The energetic content of liquid fuels is also superior, which is essential since energy needs to be carried onboard in vehicles.

In addition to biofuels, there is increasing interest towards utilizing recycled fossil-based materials such as used lubricant oils (ULO) or other waste oils for production of transportation fuels. In contrast to most biomass-derived liquids, ULO and other fossil waste oils have a distinct benefit of containing very little oxygen. On the other hand, ULO and other waste oils do contain a plurality of other impurities (metals, phosphorus, silicon, chlorine) which originate primarily from the additives that have been used in the production process. However, the hydrocarbons that are contained in recycled fossilbased materials such as ULO and other waste oils are largely paraffinic, and they fall within a boiling point range that is suitable for catalytic cracking. Waste oils such as these therefore offer an alternative for conventional cracking feeds like vacuum gas oil (VGO).

Furthermore, starting from 2020 in the European Union, the new renewable energy directive (RED II) may include some form of incentives for transportation fuels prepared from fossil-based recycled feeds. Thus, even though ULO and other waste oils are a highly challenging feedstock in terms of purification, they are regarded as an alternative refinery feed with good potential. One method for purification of waste oils is distillation; it simultaneously separates most of the metallic impurities / phosphorus and the heaviest hydrocarbons into the distillation bottoms, thus rendering the resulting distillates into a more readily utilizable form.

An alternative approach for upgrading waste oils, such as ULO is to re-refine the hydrocarbons into base oil components, e.g. by hydrotreatment, and subsequently use them in the formulation of new lubricants. In this approach, it is essential to avoid the cracking of base oil hydrocarbon chains during purification and hydrotreatment. Because of this, distillation technologies which are particularly suitable for thermally unstable materials are often utilized for fractionating ULO.

Further, US 4,512,878 A discloses a method for recycling waste oils comprising a heat soaking step, a distillation step and a hydro-refining step.

US 4411774 A discloses heat treatment of ULO in the presence of a pretreatment chemical to remove contaminants, followed by filtration, and reusing the thus treated liquids as lubricant oils.

US 3980551 A discloses demetallization of ULO in an ebullated bed reactor, followed by vacuum distillation to produce a clean fraction and a heavy fractions containing sludge and metals.

Summary of the invention

It is an object of the present invention to provide an improved method for treatment of waste oils.

The inventors of the present invention surprisingly found that a heat treatment step is suited to reduce the metal content of a waste oil material to such an extent that the heat-treated material, after removal of solid substance formed during heat treatment, can be subjected to a metaltolerant hydrocracking process without any further purification, such as distillation. More specifically, the inventors found that a heat-treated feedstock possesses suitable properties that would allow its direct forwarding into hydrocracking without a further need for distillation, thus significantly improving the yield of the pre-cracking purification process as well as the overall yield.

That is, one distinct disadvantage of distillation, though providing quite pure material, is the significant loss of hydrocarbon material into the distillation bottoms. Moreover, although the majority of the metals is fractionated into the distillation bottoms, the resulting distillates do not necessarily meet the stringent contaminant specification of fixed-bed hydrotreating/hydrocracking units. In practice, this means that a secondary means of purification has to be employed in order to further reduce the contaminant concentrations of the waste oil distillates. Depending on the distillation characteristics of the waste oil sample and the distillation methodology, the hydrocarbons that are separated into the distillation bottoms may correspond to e.g. vacuum residue (VR) type material which has a boiling point of > 550 °C and contains significant amounts of metal impurities.

Thus, since an adequate level of metal removal can be achieved without distillation, the present invention provides a process which achieves exceptionally high yields as compared to conventional techniques employing distillation to provide a feed suitable for hydrotreatment.

The present invention is defined in the independent claim. Further beneficial embodiments are set forth in the dependent claims.

Specifically, the present invention relates to a method for upgrading waste oil comprising the following steps:

subjecting a feedstock to a heat treatment (heat treatment step) to produce a heat-treated material comprising liquid components and solid components,

separating solids from the heat-treated material to produce a metaldepleted feed,

subjecting the metal-depleted feed, optionally together with a co-feed, to hydrocracking (hydrocracking step) to form a hydrocracked material, recovering at least one hydrocarbon fraction boiling in the liquid fuel range from the hydrocracked material;

wherein the feedstock has an oxygen content of at most 5.0 wt.-% on a dry basis,

wherein the heat treatment is carried out at a temperature of at least 290°C, and

wherein the step of separating solids from the heat-treated material (the step of removing insoluble components) comprises at least one of centrifugation, filtration, and sedimentation.

Further embodiments of the method according to the invention are described in the dependent claims.

In the above method, the feedstock preferably has an oxygen content, on a dry basis, in the range of 0.1 wt.-% to 5.0 wt.-%, preferably at most 4.0 wt.-%, at most 3.5 wt.-% or at most 3.0 wt.-%, and/or at least 0.2 wt.-%, at least 0.3 wt.-%, at least 0.4 wt.-% or at least 0.5 wt.-%.

In the above method, the total content of hydrogen (H) and carbon (C) in the feedstock, on a dry basis, is preferably at least 80 wt.-%, preferably at least 85 wt.%, at least 90 wt.-%, at least 92 wt.-%, at least 94 wt.-%, at least 95 wt.-%, at least 96 wt.-%, at least 97 wt.-%, at least 98 wt.-%, or at least 99 wt.-%.

Preferably, the above method further comprises a pre-treatment step of dewatering a crude feed to prepare the feedstock.

In the above method, the metal-depleted feed is preferably subjected to hydrocracking together with a co-feed.

In the above method, the co-feed is preferably a fossil-based feed, a renewable feed or a combination of both.

In the above method, the fossil-based feed is preferably a fraction from crude oil and/or the renewable feed is a material derived by deoxygenation of a renewable material.

In the above method, the metal content of the metal-depleted feed is preferably lower than the metal content of the feedstock.

In the above method, the metal content of the metal-depleted feed is preferably at most 60 wt.-% of the metal content of the feedstock, preferably at most 50 wt.-%, at most 40 wt.-%, at most 30 wt.-%, at most 20 wt.-%, at most 15 wt.-%, at most 10 wt.-% , at most 8 wt.-% , at most 7 wt.-% , at most 6 wt.-% , at most 5 wt.-% , at most 4 wt.-% , or at most 3 wt.-% of the metal content of the feedstock.

In the above method, the heat treatment is preferably carried out at a temperature of at least 290°C, preferably at least 300°C, or at least 310°C.

In the above method, the heat treatment is preferably carried out at a temperature of at least 320°C or at least 330°C.

In the above method, the heat treatment is preferably carried out at a temperature of at most 450°C, preferably at most 400°C, at most 380°C, at most 370°C, at most 360°C, at most 350°C, at most 340°C, or at most 335°C.

In the above method, the heat treatment is preferably carried out for at least 1 minute, preferably at least 2 minutes, at least 5 minutes, at least 10 minutes, at least 20 minutes, at least 30 minutes, at least 40 minutes, at least 50 minutes, at least 60 minutes, at least 80 minutes or at least 100 minutes.

In the above method, the heat treatment is preferably carried out at a pressure of 1.0 bar or more, preferably 1.2 bar or more, 1.5 bar or more, 2.0 bar or more or 3.0 bar or more.

In the above method, the feedstock preferably contains at most 20.0 wt.-% water, preferably at most 15.0 wt.-%, at most 12.0 wt.-%, at most 10.0 wt.-%, at most 8.0 wt.-%, at most 7.0 wt.-%, at most 6.0 wt.-%, at most 5.0 wt.-%, at most 4.0 wt.-%, at most 3.0 wt.-%, at most 2.0 wt.-%, at most 1.5 wt.-%, at most 1.0 wt.-%, at most 0.7 wt.-%, or at most 0.5 wt.-% water.

In the above method, the hydrocracking step is preferably carried out at a temperature in the range of 300°C to 500°C.

In the above method, the hydrocracking step is preferably carried out at a temperature of at least 310°C, at least 320°C, at least 330°C, at least 340°C, or at least 350°C, and/or at most 490°C, at most 480°C, at most 470°C, at most 460°C, at most 450°C, at most 440°C, or at most 430°C.

In the above method, the metal-depleted feed is preferably subjected to hydrocracking in the presence of a solid catalyst.

In the above method, the solid catalyst preferably contains at least one nonnoble Group VIII metal and at least one Group VIB metal and a carrier.

In the above method, the carrier preferably comprises silica, alumina or clay.

In the above method, the carrier preferably comprises Brönsted-acid component.

In the above method, the Brönsted-acid component is preferably zeolite or amorphous silica-alumina.

In the above method, the zeolite is preferably Y-zeolite, beta-zeolite or any other 12-member ring zeolite.

In the above method, the Non-noble Group VIII metal is preferably Co or Ni and Group VIB metal is Mo or W.

In the above method, the hydrogen partial pressure in the hydrocracking step is preferably in the range of 70 to 200 bar.

In the above method, the hydrocracking step is preferably carried out in an ebullated bed reactor, slurry reactor or a fixed bed reactor.

In the above method, the total content of metals and phosphorous in the feedstock is preferably in the range of 500 mg/kg to 10 000 mg/kg, preferably 1000 mg/kg to 8000 mg/kg.

In the above method, the feedstock is preferably liquid at 25°C.

In the above method, the temperature during de-watering is preferably lower than the (highest) temperature in the heat treatment step.

In the above method, the step of removing insoluble components (the step of separating solids from the heat-treated material) preferably comprises at least one of centrifugation, filtration, and sedimentation, preferably at least centrifugation.

In the above method, the heat treatment step is preferably carried out for 100 hours or less, preferably 50 hours or less, 40 hours or less, 30 hours or less, 20 hours or less, 10 hours or less, or 5 hours or less.

In the above method, a metal removal additive is preferably admixed with the feedstock in advance of or during the heat treatment step, the metal removal additive preferably being at least one selected from the group consisting of ammonium sulphate, ammonium bisulphate, diammonium phosphate, ammonium dihydrogen phosphate, calcium hydrogen phosphate, phosphoric acid, magnesium sulphate, calcium sulphate, aluminium sulphate and sodium sulphate.

A fuel component is obtainable by the above method.

Preferably, the above fuel component comprises the recovered hydrocarbon fraction, wherein the fraction is preferably a fraction boiling in the gasoline range, or a fraction boiling in the middle distillate range.

The recovered hydrocarbon fraction obtained by the above method is usable for producing a fuel or a fuel component.

The oxygen content in the feedstock can be determined by elemental analysis. In the present invention, the oxygen content is determined on a dry basis of the feedstock (excluding water, if present in the feedstock).

Brief description of the drawing

Fig. 1 is a schematic illustration of the process according to the present invention.

Detailed description of the invention

The invention is now explained in detail with reference to specific embodiments. It is to be noted that any feature of the embodiments may be combined with any feature of another embodiment provided that such a combination does not result in a contradiction.

The present invention relates to a method comprising a heat treatment step, a solids separation step, a hydrocracking step and a recovering step. The heat treatment step is a step of subjecting a feedstock to a heat treatment to produce a heat-treated material comprising liquid components and solid components. The feedstock has an oxygen content of at most 5.0 wt.-% on a dry basis (i.e. excluding water). The solids separation step is a step of separating solids from the heat-treated material to produce a metal-depleted feed. The hydrocracking step is a step of subjecting the metal-depleted feed, optionally together with a co-feed, to hydrocracking to form a hydrocracked material. The recovering step is a step of recovering at least one hydrocarbon fraction boiling in the liquid fuel range from the hydrocracked material.

The present inventors surprisingly found that heat treatment of the feedstock and subsequent solids removal is sufficient to provide a feed suited for metaltolerant hydrocracking units, such as residue hydrocracking (RHC) units. Specifically, the inventors found that distillation of the heat treated material is not necessary and thus the significant loss of valuable hydrocarbon material in the distillation bottoms can be avoided.

Further, the heat treatment may reduce fouling tendencies of the cracking catalyst and thus increase catalyst life. Although it is not desired to be bound to theory, it is assumed that the heat treatment causes reactive components in the feedstock to undergo a reaction and thus to end up as a solid material which can be removed e.g. by filtration or centrifugation. It is assumed that such reactive components are responsible for coke formation (fouling) in the hydrocracking step.

The feedstock of the present invention encompasses any material of fossil or renewable (biomass-based) origin having an oxygen content of at most 5 wt.-% on a dry basis. In a preferred embodiment, the feedstock is waste oil or de-watered waste oil. Employing a waste material (pre-used material) in the present invention provides a sustainable process of re-introducing fossil or renewable carbon material into the value chain and thus reducing the need for exploiting natural recourses. Since the feedstock has an oxygen content of at most 5 wt.-%, unprocessed bio-based oils such as crude vegetable oil, fats and the like are not included, because these materials have a high content of oxygen. Rather, the invention is concerned with material containing mainly hydrocarbons as well as contaminants, e.g. contaminants included as a result of the production method of the material or as a result of the primary use of the material.

In the present invention, the total content of metals (not including metalloids, such as Si) and phosphorous in the feedstock is preferably in the range of 500 mg/kg to 10000 mg/kg, preferably 1000 mg/kg to 8000 mg/kg. In other words, the feedstock of the present invention is preferably a contaminated material, such as a waste material. The content of metals in the feedstock can be determined using e.g. inductively coupled plasma atomic emission spectrometry based on standard ASTM D5185. For the purpose of the present invention, the total content of metals preferably refers to the total (summed) content of Al, Cr, Cu, Fe, Na, Ni, Pb, Sn, V, Ba, Ca, Mg, Mn, and Zn.

In the present invention, the oxygen content “on a dry basis” means that the oxygen content is determined under the assumption that all of the water is removed before determining the content. The oxygen content on a dry basis can be determined by drying the feedstock and determining the oxygen content (e.g. by elemental analysis). Alternatively, the oxygen content on a dry basis can be determined from a wet feedstock as follows:

oxygen content (dry basis) = 100% * {(total oxygen content of the wet feedstock, e.g. by elemental analysis) - (oxygen contained in the wet feedstock in the form of water)} / {(mass of wet feedstock) - (mass of water in the wet feedstock)}

The content (mass) of water contained in the wet feedstock can be determined by any suitable means (e.g. Karl-Fisher titration according to ASTM D6304, or distillation according to ASTM D95).

The feedstock may comprise waste oil, such as used lubricant oil (ULO). Specifically, waste oils in accordance with the present invention include any fossil (mineral based) or renewable (biomass-based) lubrication or industrial oils which have become unfit for the use for which they were originally intended, and in particular used combustion engine oils and gearbox oils and also mineral lubricating oils, oils for turbines and hydraulic oils.

The feedstock is preferably liquid at 25°C. Thus, the feedstock can be easily handled and does not require excessive heating during storage and/or transportation.

In the method of the present invention, the feedstock preferably has an oxygen content, on a dry basis, in the range of 0.1 wt.-% to 5.0 wt.-%, more preferably at most 4.0 wt.-%, at most 3.5 wt.-% or at most 3.0 wt.-%, and/or at least 0.2 wt.-%, at least 0.3 wt.-%, at least 0.4 wt.-% or at least 0.5 wt.-%.

In other words, it is preferred that the feedstock is a material containing only low amounts of oxygen.

Further, it is preferred that the total content of hydrogen (H) and carbon (C) in the feedstock, on a dry basis, is at least 80 wt.-%, preferably at least 85 wt.%, at least 90 wt.-%, at least 92 wt.-%, at least 94 wt.-%, at least 95 wt.-%, at least 96 wt.-%, at least 97 wt.-%, at least 98 wt.-%, or at least 99 wt.-%. It is preferred that the total content of hydrogen (H) and carbon (C) in the feedstock, on a dry basis, be at least 90 wt.-%. The contents of hydrogen and carbon in the feedstock can be determined by elemental analysis using e.g. ASTM D5291.

That is, the feedstock of the present invention is preferably composed predominantly of hydrocarbon material (consisting of C and H) with low contents of heteroatoms which may be contained as inorganic impurities and/or in the form of non-hydrocarbon organic material.

The method of the present invention may further comprise a pre-treatment step of de-watering a crude feed to provide the feedstock. In view of efficiency, the de-watering step needs not be carried out if the material to be processed already contains a low amount of water and thus the material can be directly used as the feedstock.

De-watering may be achieved by any suitable chemical and/or physical method. For example, an absorbent or adsorbent for water may be contacted with the crude feed or water may be removed thermally by evaporation (distillation). The temperature during de-watering is usually lower than in the heat treatment step. The water removal step is preferably carried out at a temperature of less than 150°C, preferably 130°C or less. Further, it is preferably that de-watering is carried out at ambient pressure so as to keep processing equipment simple.

De-watering the crude feed allows better performance in subsequent steps, especially in the heat treatment step. In particular, stable pressure conditions can be achieved by removing water (and optionally further light components) before the heat treatment step.

On the other hand, a certain amount of water may be present in the feedstock of the present invention. Depending on circumstances, it may be favourable to employ a water-containing feedstock without subjecting it to a waterremoval step. In any case, the feedstock of the present invention preferably contains at most 20.0 wt.-% water, more preferably at most 15.0 wt.-%, at most 12.0 wt.-%, at most 10.0 wt.-%, or at most 8.0 wt.-%. Even lower amounts of water are desirable but may cause additional efforts for removing water. Nevertheless, the feedstock may have a water content of at most 7.0 wt.-%, at most 6.0 wt.-%, at most 5.0 wt.-%, at most 4.0 wt.-%, at most 3.0 wt.-%, at most 2.0 wt.-%, at most 1.5 wt.-%, at most 1.0 wt.-%, at most 0.7 wt.-%, or at most 0.5 wt.-% water.

The method of the present invention comprises a step of removing solids (insoluble components) before performing hydrocracking. The insoluble components include anything which is insoluble in the liquid phase having been subjected to the heat treatment. More specifically, the insoluble components include particulate solids, precipitates, sludge, including (highly) viscous liquids which are immiscible with the liquid phase (which becomes the metal-depleted feed). By reducing the content of insoluble components (or by completely removing the solids) before hydrocracking, the fouling tendency can be reduced and the handling properties can be improved. Suitable methods for removing solids include, but are not limited to centrifugation, filtration and sedimentation and it is preferred that the process of the present invention comprises at least centrifugation as the only solids removal steps or as at least one of multiple solids removal steps.

In the present invention, the metal content of the metal-depleted feed is lower than the metal content of the feedstock. In other words, metals in the feedstock accumulate in the solids and are separated after the heat treatment. As a result, the metal content is reduced. In the present invention, the “metals content” does not include the content of metalloids (e.g. Si, B). At this time, the content of other contaminants (such as metalloids, phosphorous, sulphur and chlorine) may be reduced as well.

The metal content of the metal-depleted feed is preferably at most 60 wt.-% of the metal content of the feedstock, preferably at most 50 wt.-%, at most 40 wt.-%, at most 30 wt.-%, at most 20 wt.-%, at most 15 wt.-%, at most 10 wt.-% , at most 8 wt.-% , at most 7 wt.-% , at most 6 wt.-% , at most 5 wt.-% , at most 4 wt.-% , or at most 3 wt.-% of the metal content of the feedstock. The metal content may be determined by any suitable means, such as atomic spectroscopy (e.g. AAS, AES, AFS, ICP-MS), e.g. inductively coupled plasma atomic emission spectrometry based on standard ASTM D5185.

The more the metal content is reduced by the heat treatment and subsequent solids removal, the more metal-depleted feed can be employed in the subsequent hydrocracking step without being concerned about catalyst poisoning or other negative effects of metal impurities.

In the present invention, the heating temperature during the heat treatment step is preferably at least 290°C. In this respect, balance between heating temperature and heating time (residence time) influences the efficiency of the method of the present invention. Generally, the lower the heat treatment temperature is, the longer the heat treatment time should be in order to achieve the best results.

The heat treatment temperature is preferably at least 300°C, or at least 310°C and may be at least 320°C or at least 330°C.

It is particularly preferable that the heat treatment temperature is the highest temperature among all temperatures of the method of the present invention preceding the hydrocracking step.

In the present invention, the heat treatment temperature refers to the temperature of the material to be treated (i.e. of the feedstock).

If the heat treatment temperature is at least 290°C, a considerable metal depletion can be achieved. In this respect, although a reduction of metal content can be achieved even at lower temperatures, this requires very long heating times which is not therefore not preferable. On the other hand, heat treatment temperatures of much more than 400°C are usually not necessary to achieve the object of the present invention so that the heat treatment temperature is preferably 450°C or less, more preferably 440°C or less. The heat treatment temperature may further be 430°C or less, 420°C or less, 410°C or less, 400°C or less, 390°C or less, 380°C or less, 370°C or less, 360°C or less, 350°C or less, 340°C or less, or 335°C or less.

The heat treatment duration (heat treatment time / residence time) influences the efficiency of the method of the present invention as well. Generally, it is preferable that the heat treatment step is carried out for at least 1 minute so as to achieve sufficient metal reduction (solids formation) and to further enable good process control. The heat treatment time is preferably at least 2 minutes, at least 5 minutes, at least 10 minutes, at least 20 minutes, at least 30 minutes, or at least 40 minutes. The heat treatment time may further be at least 50 minutes, at least 60 minutes, at least 80 minutes or at least 100 minutes. Generally, there is no upper limit for the heat treatment time. However, in view of process efficiency, the heat treatment time if preferably no upper limit 100 hours or less, more preferably 50 hours or less, 40 hours or less, 30 hours or less, 20 hours or less, 10 hours or less, or 5 hours or less.

If the heat treatment is carried out in a batch reactor, the heat treatment time corresponds to the temperature holding time. In a continuous reactor, the heat treatment time corresponds to the residence time.

Preferably, the heat treatment step is carried out at a pressure of 0.5 bar or more, more preferably 0.8 bar or more, 1.0 bar or more, 1.2 bar or more, 1.5 bar or more, 2.0 bar or more, 3.0 bar or more, 4.0 bar or more, 5.0 bar or more, 6.0 bar or more, 8.0 bar or more, 10.0 bar or more, 12.0 bar or more, or 14.0 bar or more. An elevated pressure during the heat treatment step can reduce the evaporation tendency and thus ensure an efficient heat treatment. The pressure should be 200 bar or less, preferably 100 bar or less, more preferably 50 bar or less in order to keep technical equipment simple.

If not indicated to the contrary, a pressure referred to in the present invention means absolute pressure. The pressure values above refer to the highest pressure occurring in the heat treatment step, i.e. measured at the point/time of highest pressure. In particular, it is preferable that the heat treatment is not carried out under reduced pressure, but rather under ambient pressure or elevated pressure. Specifically, higher pressure reduces the volatilisation tendency and thus possible product loss or boiling effects (e.g. in continuous processes).

A metal removal additive may be present during the heat treatment step. The metal removal additive may be added before starting the heat treatment and/or may be added during heat treatment. Suitable metal removal additives are those mentioned in US 4411774 A, but are not limited to those. Specifically, the metal removal additive in the present invention may be one or more selected from the group consisting of ammonium sulphate, ammonium bisulphate, diammonium phosphate, ammonium dihydrogen phosphate, calcium hydrogen phosphate, phosphoric acid, and magnesium sulphate and/or one or more selected from the group consisting of calcium sulphate, aluminium sulphate and sodium sulphate. The total added amount of the metal removal additive is preferably at least 0.1 wt.-%, more preferably at least 0.5 wt.-% or at least 1.0 wt.-% relative to the dry weight of the feedstock (total weight on a dry basis). The total added amount refers to the summed amount of all added metal removal additives (but not including solvents, if any, which are added together with the metal removal additives). If the metal removal additive is one or more selected from the group consisting of calcium sulphate, aluminium sulphate and sodium sulphate, the added amount is preferably at least 2.0 wt.-%, more preferably at least 3.0 wt.-% and even more preferably at least 4.0 wt.-% so as to improve filterability. However, metal removal efficiency is improved with any (even low) amount of metal removal additive as compared to a process employing no additive at all.

In the present invention, the type of hydrocracking is not particularly limited as long as it can tolerate the metal content of the metal-depleted feed (optionally in admixture with a co-feed). A conventional hydrocracking process may be employed and applicable hydrocracking process types include fixed-bed hydrocracking, ebullated bed hydrocracking, and slurry hydrocracking.

The hydrocracking may be carried out in the presence of a solid catalyst. The solid catalyst may be a bifunctional catalyst. When using a catalyst, the cracking effect can be achieved at lower cracking temperature.

The solid catalyst preferably contains at least one non-noble Group VIII metal, at least one Group VIB metal and a carrier. Preferably both the nonnoble Group VIII metal and the at least one Group VIB metal are supported on the carrier. Any suitable carrier may be used and a carrier comprising silica, alumina or clay is preferred. Further, a carrier comprising a Brönstedacid component is preferred. The Brönsted-acid component may preferably be zeolite or amorphous silica-alumina. A suitable zeolite is Y-zeolite, betazeolite or any other 12-member ring zeolite. The non-noble Group VIII metal is preferably Co or Ni. The group VIB metal is preferably Mo or W. Specifically, the following types of catalysts are preferred, especially when supported on a carrier as mentioned above: Co-Mo, Co-W, Ni-Mo, Ni-W.

The cracking temperature is not particularly limited and any suitable temperature may be employed. Specifically, a temperature within the range of 300°C to 500°C may be employed. The cracking temperature is preferably at least 310°C, at least 320°C, at least 330°C, at least 340°C, or at least 350°C. The cracking temperature may be at most 490°C, at most 480°C, at most 470°C, at most 460°C, at most 450°C, at most 440°C, or at most 430°C.

In the hydrocracking step, the hydrogen partial pressure in the hydrocracking step is preferably in the range of 70 to 200 bar.

The hydrocracking step may be carried out in any suitable reactor and preferable is an ebullated bed reactor, a slurry reactor or a fixed bed reactor.

The feed of the hydrocracking step may comprise one or more co-feeds in addition to the metal-depleted feed of the present invention. The co-feed may be a fossil-based feed, a renewable feed or a combination of both.

The feed of the hydrocracking step preferably comprises a renewable feed component (biomass-based feed component) as a co-feed in addition to the metal-depleted feed (component). By combining the metal-depleted feed with a biomass-based feed, the method of the present invention can be even more sustainable. The feedstock, and even more the metal-depleted feed produced therefrom, comprises mainly hydrocarbons (compounds consisting of carbon atoms and hydrogen atoms) and thus the oxygen content and other properties can be finely adjusted by combining the biomass-based feed and the metal-depleted feed.

The renewable feed may be a material derived by deoxygenation of a renewable material.

Further, the feed of the hydrocracking step may comprise a fossil feed component in addition to the metal-depleted feed. The fossil feed may be a suitable feed other than the metal-depleted feed and may be a fraction from crude oil (e.g. a fraction from crude oil distillation or a fraction obtained by processing crude oil). Specifically, the fossil feed may be a conventional cracking feed, such as vacuum gas oil (VGO), or vacuum residue (VR).

By combining the metal-depleted feed with another feed (co-feed), the hydrocracking properties can be finely adjusted and the desired product distribution can be adjusted more easily. Preferably, the content of the metaldepleted feed in the (total) feed of the hydrocracking step is 50 wt.-% or less, more preferably 40 wt.-% or less, 30 wt.-% or less or 20 wt.-% or less. In order to efficiently increase the use of waste oil components, the content of the metal-depleted feed in the feed of the hydrocracking step is preferably 1 wt.-% or more, more preferably 2 wt.-% or more, 5 wt.-% or more or 8 wt.-% or more. By limiting the content of the metal-depleted feed in the (overall) hydrocracking feed, the metal content can be limited while still achieving a sustainable effect. Limited metal content allows selection of less metaltolerant catalysts and/or can improve catalyst life.

The method of the present invention further comprises a step of recovering at least one hydrocarbon fraction from the hydrocracked material (the product of the hydrocracking step / hydrocracking product). This step can be achieved by fractionating the hydrocracked material and recovering the at least one fraction. Fractionation can be carried out with any known means and preferably results in the production of at least a gasoline range fraction and/or a middle distillate range fraction.

The procedure of the present invention is schematically shown in Fig. 1. As illustrated in Fig. 1, water may be removed in a de-watering step (optional), insoluble components (precipitates) are removed e.g. in a centrifugation step. The resulting metal-depleted feed is then subjected to hydrocracking.

The present disclosure further relates to a fuel component obtainable by the method of the present invention.

As can be seen from the results of the Examples, the method of the present invention enables efficient production of fuel components, especially in the gasoline and middle distillate range, in high yield.

The present disclosure further relates to a use of the recovered hydrocarbon fraction for producing a fuel or a fuel component.

Examples

The present invention is further illustrated by way of Examples. However, it is to be noted that the invention is not intended to be limited to the exemplary embodiments presented in the Examples.

Example 1

Used lubricant oil (ULO) was used as a feedstock. The ULO contained 17.0 wt.-% water and had a high amount of metal impurities (3181 mg/kg on a wet basis = 3833 mg/kg on a dry basis; detected metals: Al, Cr, Cu, Fe, Na, Ni, Pb, Sn, V, Ba, Ca, Mg, Mn, Zn).The content of Si was detected as well and was 84 mg(kg (wet) and thus 101 mg/kg (dry). The oxygen content (on a dry basis) was 1.0 wt.-%.

The ULO was de-watered in a rotary evaporator at 100°C and 80 mbar. As a consequence, water (and light ends) were removed. The de-watered ULO was then subjected to heat treatment in a batch reactor at 320°C for 1 hour. The pressure at the beginning of the heat treatment was 1 bar and the pressure increased to approximately 23 bar as a consequence of heating in the closed vessel. The heat-treated material was cooled down to 50°C and centrifuged at 4300 rpm for 30 minutes and the liquid parts (excluding solids and sludge) were recovered as a metal-depleted feed ready to be fed to hydrocracking.

The yield of the respective process steps (wt.-% of original ULO) and the metal contents of the feedstock (ULO) and the metal-depleted feed (after centrifugation) are given in Table 1 below.

Table 1:

As can be seen from Table 1, the method of the present invention achieves a significant reduction of metals content (and of metalloids content) suitable to be fed to a metal-tolerant hydrocracking process.

Comparative Example 1:

The metal depleted feed of Example 1 was further subjected to thin film evaporation at 0.1 mbar (270-281°C). As a result, the total metals content of the distillate (b.p. < 560°C) further decreased to 2 mg/kg whereas the Si content and the P content remained almost unchanged. On the other hand, another 6 wt.-% of product (relative to dry basis of feedstock) was lost as distillation bottoms.

Example 2

Another batch of used lubricant oil (ULO-2) was used as a feedstock. The ULO-2 contained 2.6 wt.-% water and had a high amount of metal impurities (2155 mg/kg on a wet basis; detected metals: Al, Cr, Cu, Fe, Na, Ni, Pb, Sn, V, Ba, Ca, Mg, Mn, Zn).The content of Si was 278 mg/kg (wet) and the content of P was 455 mg/kg (wet). The oxygen content (on a dry basis) was 1.0 wt.-%.

The ULO-2 was de-watered in a rotary evaporator at 100°C and 80 mbar. As a consequence, water (and light ends) were removed. One part of the dewatered ULO-2 was then admixed with 3000 ppm (relative to de-watered ULO-2) of 85 wt.-% H3PO4 as a metal removal enhancer was then subjected to heat treatment in a batch reactor at 320°C for 1 hour.

Another part of the de-watered ULO-2 was subjected to heat treatment in a batch reactor at 320°C for 1 hour without additive.

In each case, the pressure at the beginning of the heat treatment was 1 bar and the pressure increased to approximately 6-7 bar as a consequence of heating in the closed vessel. The heat-treated material was cooled down to 50°C and solids were removed and the liquid parts (excluding solids and sludge) were recovered as a metal-depleted feed ready to be fed to hydrocracking.

Solids removal was effected using centrifugation at 4300 rpm for 30 minutes. In a further experiment, solids removal was effected with filtration instead of centrifugation.

The yield of the respective process steps (wt.-% of original ULO) and the metal contents of the feedstock (ULO-2) and the metal-depleted feed (after centrifugation) are given in Table 2 below.

Table 2:

As can be seen from Table 2, the method of the present invention achieves a significant reduction of metals content (and of metalloids content) suitable to be fed to a metal-tolerant hydrocracking process. Further, it can be seen that metal removal efficiency is significantly improved when employing a metal removal additive in combination with filtration as the solids removal step (preferably at least as the first stage of the metal removal step or as the only metal removal step).

Comparative Example 2

ULO-2 was subjected to heat treatment in the same manner as in Example 2 but without metal removal additive and to subsequent centrifugation. The heat-treated sample was then subjected to distillation under the conditions used in Comparative Example 1. The results are shown in Table 3 below.

Table 3:

As can be seen from Table 3, the metal removal efficiency of distillation is higher than when using only centrifugation or filtration after heat treatment. However, the content of Si is even higher (presumably because volatile Si compounds are evaporated even from the sludge) than for the technique of the present invention. In addition, a significant amount of product is lost as distillation bottoms.

Claims

1. A method for upgrading waste oil comprising the following steps:

2. The method according to claim 1, wherein the feedstock has an oxygen content, on a dry basis, in the range of 0.1 wt.-% to 5.0 wt.-%, preferably at most 4.0 wt.-%, at most 3.5 wt.-% or at most 3.0 wt.-%, and/or at least 0.2 wt.-%, at least 0.3 wt.-%, at least 0.4 wt.-% or at least 0.5 wt.-%.

3. The method according to claim 1 or 2, wherein the total content of hydrogen (H) and carbon (C) in the feedstock, on a dry basis, is at least 80 wt.-%, preferably at least 85 wt.%, at least 90 wt.-%, at least 92 wt.-%, at least 94 wt.-%, at least 95 wt.-%, at least 96 wt.-%, at least 97 wt.-%, at least 98 wt.-%, or at least 99 wt.-%.

4. The method according to any one of the preceding claims, wherein the metal-depleted feed is subjected to hydrocracking together with a co-feed, wherein the co-feed is preferably a fossil-based feed, a renewable feed or a combination of both.

5. The method according to any one of the preceding claims, wherein the metal content of the metal-depleted feed is at most 60 wt.-% of the metal content of the feedstock, preferably at most 50 wt.-%, at most 40 wt.-%, at most 30 wt.-%, at most 20 wt.-%, at most 15 wt.-%, at most 10 wt.-% , at most 8 wt.-% , at most 7 wt.-% , at most 6 wt.-% , at most 5 wt.-% , at most 4 wt.-% , or at most 3 wt.-% of the metal content of the feedstock.

6. The method according to any one of the preceding claims, wherein the heat treatment is carried out at a temperature of at least 300°C, preferably at least 310°C, at least 320°C, or at least 330°C.

7. The method according to any one of the preceding claims, wherein the heat treatment is carried out for at least 1 minute, preferably at least 2 minutes, at least 5 minutes, at least 10 minutes, at least 20 minutes, at least 30 minutes, at least 40 minutes, at least 50 minutes, at least 60 minutes, at least 80 minutes or at least 100 minutes.

8. The method according to any one of the preceding claims, wherein the hydrocracking step is carried out at a temperature in the range of 300°C to 500°C.

9. The method according to any one of the preceding claims, wherein the metal-depleted feed is subjected to hydrocracking in the presence of a solid catalyst and the solid catalyst preferably contains at least one non-noble Group VIII metal and at least one Group VIB metal and a carrier.

10. The method according to claim 9, wherein the carrier comprises silica, alumina or clay and/or wherein the carrier comprises a Brönsted-acid component, wherein the Brönsted-acid component is preferably zeolite or amorphous silica-alumina.

11. The method according to any one of the preceding claims, wherein the hydrocracking step is carried out in an ebullated bed reactor, slurry reactor or a fixed bed reactor.

12. The method according to any one of the preceding claims, wherein the total content of metals and phosphorous in the feedstock is in the range of 500 mg/kg to 10 000 mg/kg, preferably 1000 mg/kg to 8000 mg/kg.

13. The method according to any one of the preceding claims, wherein the step of separating solids from the heat-treated material (removing insoluble components) comprises at least centrifugation.

14. The method according to any one of the preceding claims, wherein a metal removal additive is admixed with the feedstock in advance of or during the heat treatment step, the metal removal additive preferably being at least one selected from the group consisting of ammonium sulphate, ammonium bisulphate, diammonium phosphate, ammonium dihydrogen phosphate, calcium hydrogen phosphate, phosphoric acid, magnesium sulphate, calcium sulphate, aluminium sulphate and sodium sulphate.

15. The method according to any one of the preceding claims, wherein the heat treatment is carried out at a temperature of at most 450°C, preferably at most 400°C, at most 390°C, at most 380°C, at most 370°C, at most 360°C, at most 350°C, at most 340°C, or at most 335°C.