WO2014177429A1

WO2014177429A1 - Catalyst and process for dewaxing of hydrocarbons

Info

Publication number: WO2014177429A1
Application number: PCT/EP2014/058171
Authority: WO
Inventors: Søren MYGIND AAGAARD; Marie GRILL
Original assignee: Haldor Topsøe A/S
Priority date: 2013-05-03
Filing date: 2014-04-23
Publication date: 2014-11-06

Abstract

In a broad form, the present invention relates to a catalytically active material which contains a Co and/or Ni, a Group VI metal and a molecular sieve active in dewaxing, and in which the total concentration of Co and/or Ni and Group VI metal is between 1 wt% and 10 wt%, with the associated benefit of such a catalytic material being active in dewaxing, while reducing the recombination of olefin intermediates with hydrogen sulfide to form mercaptans. This is due to the hydrotreatment activity of the catalytically active material due to the combined presence of Co and/or Ni and Group VI metal making surface hydrogen available, which surface hydrogen reduces the net recombination of olefins with hydrogen sulfide to form mercaptans and which surface hydrogen also minimizes the risk of deactivation of the catalyst by carbon deposits. Furthermore the present invention relates to a process for dewaxing of a hydrocarbon feed of which 80%, preferably 90% and most preferably at least 98%boils in the temperature range 150-400°C.

Description

Title: Catalyst and process for dewaxing of hydrocarbons

The invention relates to a process for dewaxing of a hydro^¬ carbon mixture boiling in the diesel temperature range.

The hydrocarbon mixtures of relevance for the present dis^¬ closure are boiling in the diesel temperature range, and may originate from atmospheric or vacuum fractionation of a hydrocarbon mixture with a wide boiling range. The hydro- carbon mixture may originate from a variety of sources, in^¬ cluding mineral oils, renewable oils (including oils of vegetable and/or animal origins), hydrocarbons synthetical^¬ ly manufactured from synthesis gas, e.g. via the well-known Fischer Tropsch reaction where the synthesis gas may origi- nate from, among other, from biomass and coal gasification, natural gas reforming and coke-oven gas, or intermediates from processes treating such hydrocarbon mixtures as well as a mixture of hydrocarbons from any of the mentioned sources. The present invention is mainly focused on dewax- ing of hydrocarbons boiling in the diesel boiling range 150 to 400°C.

As it is well known to the skilled person, e.g. from the European standard EN 590 for diesel fuels, a hydrocarbon mixture may, depending upon its origin, have satisfactory cold-flow properties at all relevant temperatures for a specific application, it may need to be improved for cer^¬ tain applications, often in connection with seasonal varia^¬ tion of temperature (typically in winter) , or it may need improvement throughout the year. In addition a diesel fuel must also fulfill other requirements, including maximum sulfur content and ignition properties, which may not be fulfilled by the raw materials as supplied to the dewaxing process .

Problematic cold flow properties i.e. crystallization or partial solidification at low temperatures are most common^¬ ly related to long (C7+) straight chain n-paraffins, where^¬ as their branched isomers, also called isomerized paraffins ( i-paraffins ) , have more favorable cold flow properties. Several methods of optimizing cold flow properties are available, and as they all aim at reducing the presence or at least the effect of the wax-like n-paraffins they are commonly called dewaxing. Product blending may improve the cold flow properties by dilution of the feedstock with lower boiling streams (for example kerosene) or appropriate additives (depressants of crystal formation) to feedstock oils. Albeit technological^¬ ly simple, these methods are traditionally expensive.

Products with acceptable cold flow properties may also be obtained by catalytic hydrocracking of diesel feedstocks. This reaction reduces the size of long n-paraffins produc^¬ ing shorter molecules giving a diesel product with satis- factory cold-flow properties. Hydrocracking involves loss of product (commonly called diesel yield loss) and consump^¬ tion of hydrogen.

A further route to improvement of the cold flow properties of products is catalytic hydroisomerization . Appropriate catalysts are active in promoting isomerization reactions in the presence of hydrogen, providing isomers with various degree of branching from the original straight chain paraf^¬ fins .

Hydroisomerisation allows higher yield of the product frac- tion of interest and a lower consumption of hydrogen compared to hydrocracking .

However, the reactions occurring in industrial processes are never 100% selective, and therefore a need to identify the optimal balances between reactions for the different feeds always exists. In relation to the present disclosure the desired cold flow improvement must be balanced against the effect on other diesel characteristics of the product, such as sulfur content, ignition properties and density, the related yield loss and the risk of catalyst deactiva^¬ tion by carbon formation. The catalysts available may ei^¬ ther avoid a yield loss by being reaction specific towards hydroisomerisation, with virtually no yield loss, or by catalyzing hydrocracking while being reactant specific, such that only linear chains, i.e. n-paraffins, are hy- drocracked, such that yield loss occurs only from hy^¬ drocracking of paraffins which have problematic cold flow properties . The catalytically active materials used for dewaxing often comprises a noble or a non-noble metal component selected from Group VIIIB of the Periodic System in combination with a molecular sieve such as SAPO-5, SAPO-11, SAPO-31, SAPO- 34, SAPO-41, ZSM-11, ZSM-22, ZSM-23, MCM-41, zeolite Y, ZSM-5, zeolite beta, other molecular sieves or combinations of these molecular sieves and a support containing alumina, silica, titania or silica-alumina or combinations thereof. A process for dewaxing of diesel range hydrocarbons is car^¬ ried out immediately downstream a hydrodesulfurisation process, in the presence of ¾S produced in the hydrodesulfu- risation (i.e. in sour mode) . If olefins are present a com^¬ mon side reaction over a dewaxing catalyst is the recombi^¬ nation of olefins and ¾S to form mercaptans . To remove these from the product a final layer of hydrodesulfurisa^¬ tion catalyst is often added to the output of the reactor. Alternatively the ¾S may be removed, i.e. operation in sweet mode. Both of these solutions add cost and complexi^¬ ty.

US2011/0315599 discloses a process integrating cracking and dewaxing with intermediate removal of sour water, in which a dewaxing catalyst comprising about 0.6 wt% Pt and 65 wt% ZSM-48 on 35 wt% titania is used. Satisfactory cold flow parameter improvement and sulfur removal are reported. The application includes speculations on other compositions, but no experimental data.

US2003/0168379 also discloses an integrated process for dewaxing of lubes boiling above 350°C, in which the dewax^¬ ing step is based on a catalyst comprising 0.6 wt% Pt, 65 wt% zeolite (ZSM-48, ZSM-23 or ZSM-35) and 35 wt% alumina. Satisfactory cold flow parameter improvement is seen, but the quality of sulfur removal is not reported.

EP0140608 discloses a process for hydrocracking and dewax- ing comprises at 4wt% Ni, 10wt% W and 50-75 wt% of at least two zeolites, one of which is rare-earth exchanged. Sulfur removal is not reported, as the feed sulfur content is not reported, but the product is reported to contain 20 ppm sulfur. Only 31% of the product is Diesel.

US 4,600,497 discloses a process for hydrotreating and dewaxing a simulated shale oil intermediate, with 50% boil^¬ ing above the Diesel range. The catalyst used comprises ap^¬ proximately 2.0 wt% Ni, 16.5wt% W and 24wt% ZSM-5 and the cold flow improvement and desulfurization is reported as satisfactory .

US 4,443,327 discloses a process for dewaxing a lube feed over a nickel exchanged ZSM-5 zeolite, comprising 1.1 wt% Ni and 99 wt% ZSM-5. A separate hydrotreatment section is required for removal of sulfur.

US 5,935,414 discloses a combined hydrocracking and dewax^¬ ing process in which a dewaxing catalyst comprising 0.55wt% Ni, 12.1 wt% W and 42 wt% ZSM-5 is used for dewaxing and a catalyst comprising 3.0wt% Ni, 18.3 wt% W and 5.2 wt% zeo lite Y is used for hydrocracking. The combined process is demonstrated to lower the boiling point, improve cold flow properties and remove sulfur to a level of 15-76 ppm.

These processes all relate to dewaxing and most often also hydrocracking of a hydrocarbon feed comprising a large amount of heavy hydrocarbons. None of them consider the specific requirements of a process for dewaxing of diesel and middle distillate, in which the diesel yield loss due to cracking must be minimized and the ability to function under sour conditions and provide a low sulfur level is im^¬ portant . Now according to the present disclosure it has been found that a favorable balance between catalyst stability, cold flow improvement, and sulfur removal may be obtained for catalysts which comprise Co and/or Ni, a Group VI metal and a molecular sieve active in dewaxing, and comprising a group VI metal, a group VIIIB metal and in which the coke formation and diesel yield loss is minimized by keeping the ratio of the sum of the moles of group VIIIB metal and group VI metal to the moles of aluminum in molecular sieve above 1.

Definitions

As used herein Group VIIIB shall be construed as elements from the periodic table according to the CAS definition, i.e. as the elements of the combined 1990 IUPAC Groups 8, 9 and 10. Similarly Group VI shall be construed as the ele^¬ ments of the 1990 IUPAC Group 6. The term metal active in hydrotreatment shall be construed as a Group VIIIB and a Group VI metal, when present in combination.

Elements and chemical compounds may herein be referred to by their symbol from the periodic table of elements (e.g. Ni) or by their name (nickel) . No significance shall be taken from this.

As used herein molecular sieves and zeolites shall be de^¬ fined by a well-known trivial name or by the framework type codes assigned by the Structure Commission of the Interna^¬ tional Zeolite Association.

As used herein the aluminum content of a molecular sieve , shall be understood as the bulk elemental aluminum content measured by chemical analysis of the molecular sieve, and excluding the content of aluminum in the amorphous support, but including lattice as well as non-lattice aluminum in the molecular sieve, all as measured on a dry basis.

As used herein the silica : alumina ratio for a molecular sieve shall be understood as the molar ratio between S1O₂ and AI₂O₃ in the zeolitic framework. As used herein n-paraffins shall be understood as straight chain paraffins, and i-paraffins shall be understood as paraffins, having side chains, including but not limited to iso-paraffins , which have a single methyl-group proximate to the end of the carbon chain, whereas i-paraffins is un- derstood by the skilled person as any mono-branched or poly-branched paraffin. Paraffins shall be understood as a collective term corresponding to alkanes.

As used herein mercaptans shall be construed as hydrocar- bons comprising reactive sulfur, typically comprising a -SH group .

As used herein in the following, diesel or a feedstock boiling in the diesel temperature range, shall be under- stood as a mixture comprising hydrocarbons of which at least 80%, preferably 90% and most preferably at least 98% boils in the temperature range 150-400°C. The term may also cover feedstock or products appropriate as diesel compo^¬ nents without fulfilling all requirements for diesel fuels in e.g. the standard EN590. As used herein the boiling point shall be construed as ei^¬ ther the boiling determined by distillation according to ASTM D86 or as the simulated distillation boiling point ob^¬ tained from gas chromatographic results according to ASTM D7213 or similar simulated methods. The reported experi^¬ mental data will be based on ASTM D7213 boiling points.

As used herein a cold flow parameter shall be understood as any parameter, typically a temperature, reflecting a flow property of a hydrocarbon mixture at low temperatures, in^¬ cluding the parameters cloud point, pour point, freezing point and cold filter plugging point (CFPP) . Common for these parameters are that they define the requirement to low viscosity of diesel under cold conditions as it is also specified in the standard EN 590 specifying requirements to diesel, and the improvement of cold flow properties or of any one of these parameters shall unless stated otherwise be understood as equivalent. As used herein dewaxing of a hydrocarbon shall be understood as the process of improving cold flow parameters of the hydrocarbon mixture. Primarily dewaxing will be in the form of catalytic dewaxing, which may involve catalytically promoted hydroisomerisation from n-paraffins to i-paraffins and/or catalytically promoted hydrocracking involving breaking the long paraffins into shorter paraffins.

As used herein hydrocracking shall be understood as the process of splitting a hydrocarbon into smaller fragments in the presence of hydrogen. Hydrocracking may without be^¬ ing bound by theory occur as a molecular sieve bulk hydrocracking reaction splitting large hydrocarbons complete- ly into small gaseous (C1-C4) fragments or as molecular sieve surface hydrocracking, typically splitting the hydro^¬ carbon in two. As used herein hydroisomerisation or isomerization shall be understood as the process of rearranging a hydrocarbon chain, typically with the effect of obtaining an increased branching, and thus improved cold flow properties. The num^¬ ber of carbon atoms in the hydrocarbon is not changed by hydroisomerisation.

As used herein the concentrations specified for catalyst composition shall be understood as the weight percentage on dry basis. For metal the concentration is given as concen- trations of elemental metal. Ratios will be given as molar ratios unless stated otherwise.

As used herein a molecular sieve catalytically active in dewaxing shall be defined as any molecular sieve which un- der dewaxing conditions catalyzes a transformation of a hydrocarbon which improves the cold flow properties of the hydrocarbon mixture, irrespectively of the nature of the catalyzed reaction. As used herein the unit Nl/1 shall indicate the volume of gas (in normal liters, i.e. liters at 0°C and 1 bar) per volume of liquid (in liters at 15°C and 1 bar) .

As used herein dewaxing conditions shall be defined as a pressure of 20-100 barg and reaction temperatures 200-450°C and a hydrogen to oil ratio of 50-2000 Nl/1 oil and a space velocity (LHSV) of 0.1-20 h^"1. In a broad form, the present invention relates to a cata^¬ lytically active material which contains a Co and/or Ni, a Group VI metal and a molecular sieve active in dewaxing, and in which the total concentration of Co and/or Ni and

Group VI metal is between 1 wt% and 10 wt%, with the asso^¬ ciated benefit of such a catalytic material being active in dewaxing, while reducing the recombination of olefin intermediates with hydrogen sulfide to form mercaptans . This is due to the hydrotreatment activity of the catalytically ac^¬ tive material due to the combined presence of Co and/or Ni and Group VI metal making surface hydrogen available, which surface hydrogen reduces the net recombination of olefins with hydrogen sulfide to form mercaptans and which surface hydrogen also minimizes the risk of deactivation of the catalyst by carbon deposits.

In a further embodiment the concentration of molecular sieve is from 1 wt% to 50 wt%, preferably from 10 wt% to 40 wt%, with the associated benefit of providing a dewaxing effect by the presence of the molecular sieve, while opti^¬ mizing the cost and this effect by limiting the amount of molecular sieve. In a further embodiment the molecular sieve is a zeolite and the concentration of zeolitic aluminum is between 0.005 wt%, 0.01 wt% or 0.1 wt% and 1 wt%, 3 wt% or 5 wt%, with the associated benefit of limiting the hydrocracking activity of acidic sites, which typically will be associated with the amount of aluminum in zeolites and with the amount of silica in SAPO type molecular sieves. In a further embodiment the molecular sieve is a zeolite and the catalytically active material has a ratio of the total number of moles of Co and/or Ni and a Group VI metal to the number of moles of zeolitic aluminum of at least 0.5 preferably at least 1, with the associated benefit that the presence of hydrogen on Group VIIIB and Group VI sites is sufficient to provide hydrogen for acidic sites active in hydrocracking, which typically are associated with zeolitic aluminum, and thus specifically reduces the risk of carbon formation and mercaptan recombination.

In a further embodiment the molecular sieve is a zeolite and the ratio between the total number of moles of Co and/or Ni and a Group VI metal to the number of moles of zeolitic aluminum is less than 300, preferably less than 50 and even more preferably less than 6 with the associated benefit of limiting the relative amount of active metal that said catalytically active material becomes more active in improving the cold flow properties at reduced metal to zeolitic alumina ratios.

In a further embodiment the molar ratio of Group VIIIB met^¬ al to Group VI metal is 0.05-10 with the associated benefit of such a material having a significant hydrotreatment ac- tivity, reducing the formation of mercaptans by recombina^¬ tion of ¾S and e.g. olefins.

In a further embodiment the Group VI metal is molybdenum or tungsten with the associated benefit of molybdenum and tungsten of providing a hydrotreatment activity in combina^¬ tion with a Co and/or Ni . As it is well known to the skilled person, the mechanisms of catalytically active ma^¬ terials comprising molybdenum or tungsten are very similar.

In a further embodiment the molecular sieve active in dewaxing, is a zeolite, preferably taken from the group consisting of zeolites with framework type codes BEA, MFI, MTT, and TON or from molecular sieves of the SAPO type with the associated benefits of said molecular sieves being highly active in dewaxing.

In a further embodiment the zeolite is taken from the group consisting of ZSM-5, ZSM-22, ZSM-23 and beta zeolite with the associated benefit of ZSM-5 being selective for bulk cracking of linear paraffins, ZSM-22, and ZSM-23 being se- lective for hydroisomerisation of linear paraffins and beta zeolite being selective for end-group cracking and hy- drocracking of aromatics.

In a further embodiment the catalytically active material is formed from a precursor for a catalytically active mate^¬ rial by sulfidation, either as presulfidation or in-process sulfidation, with the associated benefit of said sulfided catalyst being highly active in hydrogenation compared to the unsulfided catalyst precursor.

A further aspect of the present disclosure relates to a process for dewaxing of a hydrocarbon feed of which 80%, preferably 90% and most preferably at least 98% boils in the temperature range 150-400°C into a hydrocarbon product, according to which said hydrocarbon feed contacts a material catalytically active in dewaxing under dewaxing condi^¬ tions, with the associated benefit of such a process being simple and well suited for diesel and middle distillate dewaxing, in which the boiling point profile of the product is not substantially changed. In a further embodiment said dewaxing process conditions are defined by the temperature being 200-450°C, the pres^¬ sure being 20-100 barg, the hydrogen to oil ratio being 50- 2000 Nl/1 and space velocity (LHSV) being 0.1-20 h^"1 with the associated benefit of said process conditions being highly suited for the dewaxing of paraffins, while minimiz^¬ ing the product loss.

In a further embodiment said hydrocarbon feed is provided as a product from a pre-treatment process step in which a hydrocarbon feed for pre-treatment comprising at least 100 ppm organic sulfur is directed to contact a material active in hydrodesulfurisation under hydrodesulfurisation conditions with the associated benefit of the upstream hy- drodesulphurization being stabilized, by either avoiding formation of mercaptans from hydrogen sulfide and olefins, or by immediate hydrodesulfurization of any mercaptans and other organic sulfur formed. For this the hydrotreatment site in form of combined presence of a group VIIIB and a group VI metal is very important as it will provide reac- tive hydrogen atoms.

In a further embodiment the hydrodesulfurisation conditions are defined by the temperature being 200-450°C, the pres^¬ sure being 20-200 barg, the hydrogen to oil ratio being 50- 2000 Nl/1, and space velocity (LHSV) being 0.1-10 h^"1. In the composition of catalytically active materials cost as well as effects must be considered. For e.g. a material catalytically active in dewaxing it is required to identify a favorable balance between stability of the catalytically active material, cold flow improvement, yield loss, sulfur removal and ignition properties. One aspect involves providing a high amount of zeolitic aluminum, with the effect of providing an active hydrocracking catalyst. However, the use of such an active catalyst also involves the risk of excessive dehydrogenation of the feedstock to carbon deposits which may block the active surface of the cat^¬ alyst. Therefore, without being bound by theory, it is be^¬ lieved that an increase in the metallic sites relative to the acid sites in the molecular sieve framework will in- crease hydrogen availability relative to the hydrocracking activity of acidic sites (related to aluminum for zeolites, but possibly to other atoms for other molecular sieves) and thus reduce the risk of carbon deposition. By applying a layer or clusters of metals catalytically ac^¬ tive in hydrotreatment to the surface, the hydrogen availa^¬ bility is increased to a level beyond the consumption of hydrogen, which reduces the risk of carbon formation. The increase in hydrogen availability at the surface also inhibits the catalytic dewaxing because the hydrogen satu^¬ rates olefins, which is a precursor in the catalytic dewax^¬ ing. Hence, a balance between the amount of hydrogen needed at the surface and maximum activity is necessary.

It has further been found that shape selectivity of molecu^¬ lar sieve may be employed, such that long and relatively narrow molecules such as linear n-paraffins can enter the molecular sieve pores in which they are hydrocracked to gaseous molecules opposed to more bulky molecules such as i-paraffins and aromatics. Therefore certain groups of mo- lecular sieves favoring such reactions may be preferred.

The preferred molecular sieves for this invention are se^¬ lected from the group consisting of molecular sieves having the framework type codes MFI, MTT and TON. For catalytical- ly active materials involving these types of molecular sieves, the preferred metal to aluminum ratio is quite low, e.g. 0.5 to 6 but materials with the metal to aluminum ra^¬ tio being 0.5 to 50 or even 0.5 to 300 will also be func^¬ tional, but the activity will decrease with higher metal to aluminum ratio.

Alternatively diesel cold flow property improvement may em^¬ ploy molecular sieves catalyzing hydrocracking on their surface, in which the hydrocarbon is split, in typically two smaller hydrocarbons, with associated improved cold flow properties. For this purpose the preferred molecular sieves are selected from zeolites having the framework type code BEA, which also have the benefit of catalyzing hy^¬ drocracking of aromatic rings, such that aromatics are transformed into branched or linear paraffins, with im- proved ignition properties. For catalytically active mate^¬ rials involving these types of zeolites, the preferred met^¬ al to aluminum range may be 0.5 to 20 or even higher before the activity decreases. Materials with the metal to alumi^¬ num range being 0.5 to 50 or even 0.5 to 300 will also be functional. A further reaction pattern in the presence of molecular sieves is the isomerization of n-paraffins into i- paraffins . These reactions are mainly catalyzed by zeolites such as ZSM-22 and ZSM-23. For catalytically active materi- als involving these types of zeolites, the preferred metal to aluminum ratio is quite low, e.g. 0.5 to 6 but materials with the metal to aluminum ratio being 0.5 to 50 or even 0.5 to 300 will also be functional, but the activity will decrease with higher metal to aluminum ratio.

Finally the formation of mercaptans during dewaxing has been considered. In the typical process, a sulfur contain^¬ ing diesel hydrocarbon mixture is hydrotreated to transform organic sulfur to hydrocarbons and hydrogen sulfide, fol- lowed by dewaxing. In the presence of a normal hydrocrack- ing catalyst intermediate olefins may be formed, which may recombine with hydrogen sulfide and produce mercaptans. However, it was found that using a dewaxing catalyst having a hydrotreatment activity, due to a combined presence of Co and/or Ni and a Group VI metal in the catalytically active material, resulted in a lower concentration of mercaptans in the hydrocarbon product, compared to using a dewaxing catalyst without hydrotreatment activity. The reason was identified to be that a recombination of hydrogen sulfide and olefins into mercaptans takes place where a catalyti^¬ cally dewaxing catalyst without hydrotreatment activity is used, but that this recombination is reversed in the pres^¬ ence of catalytic sites active in hydrotreatment. Without this net desulphurization effect it has been common prac- tice to add a layer of catalytically active material in hy^¬ drotreatment below the catalytically active material in dewaxing, but this additional layer may be avoided, with the effect of cost savings and additional availability of reactor volume.

As it is well known to the skilled person, the mechanisms of catalysis by Group VIIIB metals, specifically Ni and Co, are very equivalent, with cobalt being more active than nickel under low pressure conditions, and nickel being more active than cobalt under high pressure conditions. Similar^¬ ly the catalytic effects of using Group VI metals, specifi- cally Mo and W, are very equivalent, and the use of these metals is very widespread in hydrocracking and hydrotreat- ment catalyst, and interchanging within each group will only show moderate differences in catalytic mechanisms, which will be predictable to the skilled person, especially when considering process pressure and other process conditions.

Examples :

In the following examples all amounts of materials (except water) are stated on dry basis. The shape of catalysts and other specifics are stated as examples only, and shall not be construed as limiting for the scope of the invention, unless stated in the claims.

In the following all reported boiling points are determined according ASTM D7213.

Catalyst A, Ni on ZSM-5, according to the prior art was prepared as follows: 25 g of ZSM-5 with a molar sili^¬ ca: alumina ratio of 80 was mixed with 75 g of aluminium ox- ide and 113 g of water for 18 minutes and extruded in 1/16" cylinder shape. The extrudates were dried at 200°C for 2 hours and calcined for 6 hours at 525°C. The dried and cal- cined extrudates were pore-volume filled with an alkaline solution of nickelhydroxycarbonate and dried for 2 hours at 250°C and then calcined for 5 hours at 525°C. The amount of nickelhydroxycarbonate was adjusted to produce a catalyst with 1.8 wt% elemental Ni content on dry weight basis, in the absence of Mo. The molar ratio of the sum of Mo and Ni to zeolitic Al was 2.8.

Catalyst B, Ni-Mo on ZSM-5, was prepared similarly, but the dried and calcined extrudates were pore-volume filled with an alkaline solution of ammoniumdimolybdate (ADM) and nick^¬ elhydroxycarbonate and dried for 2 hours at 250 °C and then calcined for 5 hours at 525°C. The amount of ADM and nick^¬ elhydroxycarbonate was adjusted to produce a catalyst with 3.9 wt% elemental Mo and 1.1 wt% elemental Ni content on dry weight basis, i.e. a molar Ni:Mo ratio of 0.46. The mo^¬ lar ratio of the sum of Mo and Ni to zeolitic Al was 6.2.

Catalyst C, Ni-Mo on ZSM-5, was prepared as catalyst B with the exception that the amount of elemental Ni was adjusted to 0.6 wt% and the amount of elemental Mo was adjusted to 2 wt%, i.e. a molar Ni:Mo ratio of 0.49. The molar ratio of the sum of Mo and Ni to zeolitic Al was 3.2. Catalyst D, Ni-Mo on ZSM-5, was prepared as catalyst B with the exception that the amount of elemental Ni was adjusted to 1.7 wt% and the amount of elemental Mo was adjusted to 6.2 wt%, i.e. a molar Ni:Mo ratio of 0.45. The molar ratio of the sum of Mo and Ni to zeolitic Al was 10.0.

Catalyst E, Ni-Mo on ZSM-23, was prepared accordingly: 28 g of ZSM-23 with a molar silica : alumina ratio of 43 was mixed with 72 g of aluminium oxide and 118 g of water for 16 minutes and extruded in 1/16" cylinder shape. The extru- dates were dried at 200°C for 2 hours and calcined for 6 hours at 525°C. The dried and calcined extrudates were pore-volume filled with an alkaline solution as catalyst B with the exception that the amount of elemental Ni was ad^¬ justed to 1.4 wt% and the amount of elemental Mo was ad^¬ justed to 5.2 wt%, i.e. a molar Ni:Mo ratio of 0.43. The molar ratio of the sum of Mo and Ni to zeolitic Al was 3.9.

Catalyst F, Ni-Mo on Beta zeolite, was prepared according^¬ ly: 25 g of Beta zeolite with a molar silica : alumina ratio of 300 was mixed with 75 g of aluminium oxide and 118 g of water for 21 minutes and extruded in 1/16" cylinder shape. The extrudates were dried at 200°C for 2 hours and calcined for 6 hours at 525°C. The dried and calcined extrudates were pore-volume filled with an alkaline solution as cata^¬ lyst B with the exception that the amount of elemental Ni was adjusted to 0.6 wt% and the amount of elemental Mo was adjusted to 2 wt%, i.e. a molar Ni:Mo ratio of 0.49. The molar ratio of the sum of Mo and Ni to zeolitic Al was 11.9.

Catalyst G, Co-Mo on ZSM-5, was prepared similarly to Cata- lyst C, but the dried and calcined extrudates were pore- volume filled with an alkaline solution of ammoniumheptamo- lybdate and cobaltnitratehexahydrate and dried for 2 hours at 250°C and then calcined for 5 hours at 525°C. The amount of ADM and nickelhydroxycarbonate was adjusted to produce a catalyst with 2.1 wt% elemental Mo and 0.6 wt% elemental Co content on dry weight basis, i.e. a molar Co:Mo ratio of 0.49. The molar ratio of the sum of Mo and Co to zeolitic Al was 3.3.

Catalyst H, Ni-W on ZSM-5, was prepared similarly to Cata- lyst C, but the dried and calcined extrudates were pore- volume filled with an alkaline solution of ammoniummeta- tungstate (AMT) and nickelnitrate and dried for 2 hours at 250°C and then calcined for 5 hours at 525°C. The amount of AMT and nickelnitrate was adjusted to produce a catalyst with 3.9 wt% elemental W and 0.6 wt% elemental Ni content on dry weight basis, i.e. a molar Ni:W ratio of 0.46. The molar ratio of the sum of W and Ni to zeolitic Al was 3.2.

In a comparative evaluation of catalysts A, B, C and D, the catalysts were sulfided by methods well known to the skilled person, and a hydrotreated straight-run diesel feedstock, characterized in Table 1 was subjected to dewax- ing under the conditions 360°C, 60 barg, ¾ to oil ratio of 230 Nl/1 and an LHSV of 2 h^-1. Treat gas composition was 3.2 vol% H₂S, 0.1 vol% NH₃ and 96.7 vol% H₂ and hydrocar^¬ bons. The further comparative evaluation of catalyst E, and F was made under similar conditions, but with adjusted tem^¬ perature and/or LHSV to compensate for differences in the catalyst activity. Catalyst E wasted tested at 375°C and LHSV of 1 h^-1 and catalyst F, G and H were tested at 370°C and LHSV of 2 h^"1. Table 1

Specific Gravity.

Table 2 characterizes the total liquid product hydrocarbon mixture according to these experiments. As it is seen from Table 2 the cloud point is improved by 29°C by Catalyst C. For similar improvements in the cloud point, Catalyst A was found to have a significantly higher total liquid product sulfur content primarily consisting of mercaptans.

The results for catalysts A, B, C and D demonstrate that for catalysts comprising ZSM5, the absence of a Group VI metal (Catalyst A) results in poor desulfurization . In the presence of both Group VIIIB and Group VI metal the desul- furization increases with increasing ratio of active metals to zeolitic aluminum.

The results for Catalysts B and C demonstrates that for similar concentrations of active metals, CPI is highest at a ratio of active metals to zeolitic aluminum around 3 for comparable ZSM5 based catalysts. A ratio below 0.5 results in a catalyst with very low CPI activity, and at increasing ratios the CPI activity decreases gradually.

The results for Catalysts B, C, G and H demonstrates that effects of Mo and W are interchangeable and similarly that Co and Ni are interchangeable (note that the experiments of Catalysts G and H were conducted at higher temperature) .

The results for Catalysts E and F demonstrate that trends identified for ZSM5 zeolite may be extended to other dewax- ing molecular sieves such as beta zeolite and ZSM23 zeo^¬ lites.

Table 2

Cloud Point Improvement

2 Specific Gravity. Not measured for G and H.

³ The ratio between Group VIIIB metal and Group VI metal

⁴ The ratio of the sum of Group VIIIB metal and Group VI metal to molecular sieve aluminum.

Claims

Claims :

1. A catalytically active material or a precursor for a catalytically active material containing Co and/or Ni, a Group VI metal and a molecular sieve active in dewaxing, in which the totaL concentration of Co and/or Ni and Group VI metal is between than 1 wt% and 10 wt%.

2. A catalytically active material to claim 1 wherein the concentration of molecular sieve is from 1 wt% to 50 wt%, preferably from 10 wt% to 40 wt%.

3. A catalytically active material according to claim 1 or

2 wherein the molecular sieve is a zeolite and the concentration of zeolitic aluminum is between 0.005 wt%, 0.01 wt% or 0.1 wt% and 1 wt%, 3 wt% or 5 wt%.

4. A catalytically active material according to claim 1, 2 or 3 wherein the molecular sieve is a zeolite and the ratio of the total number of moles of non-noble Co and/or Ni and a Group VI metal to the number of moles of zeolitic aluminum is at least 0.5 preferably at least 1.

5. A catalytically active material according to claim 1, 2,

3 or 4, in which the molecular sieve is a zeolite and the ratio of the total number of moles of Co and/or Ni and a Group VI metal to the number of moles of zeolitic aluminum is less than 300, preferably less than 50 and even more preferably less than 6.

6. A catalytically active material according to claim 1, 2, 3, 4 or 5, wherein the molar ratio of Co and/or Ni to Group VI metal is 0.05-10.

7. A process according to claim 1, 2, 3, 4, 5 or 6, where the Group VI metal is molybdenum or tungsten.

8. A catalytically active material according to claim 1, 2, 3, 4, 5, 6 or 7, where the molecular sieve active in dewax- ing, is a zeolite, preferably taken from the group consisting of zeolites with framework type codes BEA, MFI, MTT, and TON.

9. A catalytically active material according to claim 1, 2, 3, 4, 5, 6,' 7 or 8, where the zeolite is taken from the group consisting of ZSM-5, ZSM-22, ZSM-23 and beta zeolite.

10. A catalytically active material according to one of the claim 1, 2, 3, 4, 5, 6, 7, 8 or 9 which is formed from a precursor for a catalytically active material by sulfida- tion, either as presulfidation or in-process sulfidation.

11. A process for dewaxing of a hydrocarbon feed of which 80%, preferably 90% and most preferably at least 98% boils in the temperature range 150-400°C into a hydrocarbon product,

according to which said hydrocarbon feed contacts a material catalytically active in dewaxing according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 under dewaxing conditions.

12. A process according to claim 11 wherein the dewaxing conditions defined by the temperature being 200-450°C

the pressure being 20-100 barg

the hydrogen to oil ratio being 50-2000 Nl/1

and space velocity (LHSV) being 0.1-20 h^"1

13. A process according to claim 11 or 12 wherein said hydrocarbon feed is provided as a product from a pre- treatment process step in which a hydrocarbon feed for pre- treatment comprising at least 100 ppm organic sulfur is directed to contact a material active in hydrodesulfurisation under hydrodesulfurisation conditions.

14. A process according to claim 13 wherein the hydrodesul- furisation conditions are defined by

the temperature being 200-450°C

the pressure being 20-200 barg

the hydrogen to oil ratio being 50-2000 Nl/1

and space velocity (LHSV) being 0.1-10 h^"1