CORONADO IRENE (FI)
| US20110027169A1 | 2011-02-03 | |||
| US20170267932A1 | 2017-09-21 |
| CLAIMS 1. A method for treating a side water frac tion (1) which comprises at least one undesired com pound and which is formed in a thermochemical treat ment of biomass, cha r a c t e r i z e d in that - the side water fraction (1) comprising at least one undesired organic compound is treated by means of a reforming treatment (2) in order to convert the organic compound into at least hydro gen (5) and optionally also other compounds (6) selected from the group comprising organic com pounds, hydrocarbons, carbondioxide, carbonmonox- ide and their combinations, and - the reforming treatment (2) is catalyzed by Ni/NiAl204 catalyst (3) . 2. The method according to claim 1, cha r a c t e r i z e d in that the Ni/NiAl204 catalyst (3) is Ni/NiAl204 washcoat catalyst. 3. The method according to claim 1 or 2, cha r a c t e r i z e d in that the Ni/NiAl204 catalyst (3) is Ni/NiAl204 spinel washcoat catalyst. 4. The method according to any one of claims 1 to 3, cha r a c t e r i z e d in that the Ni/NiAl204 catalyst (3) is formed by arranging Ni/NiAl204 as a thin washcoat layer onto a substrate. 5. The method according to any one of claims 1 to 4, cha r a c t e r i z e d in that Ni content of the Ni/NiAl204 catalyst is 8 - 15 wt%. 6. The method according to any one of claims 1 to 4, cha r a c t e r i z e d in that the Ni/NiAl204 catalyst (3) is prepared such that Ni-precursors are impregnated into a boehmite carrier material to form a catalytic material, the catalytic material is dried and calcinated, and a slurry comprising at least the catalytic material is prepared and stirred, and the substrate is washcoated with the slurry, and the wash- coated substrate is thermally treated. 7. The method according to any one of claims 1 to 5, cha r a c t e r i z e d in that the Ni/NiAl204 catalyst (3) is prepared such that Ni-precursors are impregnated by means of an incipient wetness impregna tion into a boehmite carrier material to form a cata lytic material, the catalytic material is dried and calcinated, and a slurry comprising at least the cata lytic material is prepared and stirred, and the sub strate is washcoated with the slurry, and the wash- coated substrate is dried, calcinated and treated by reduction . 8. The method according to any one of claims 1 to 7, cha r a c t e r i z e d in that the reforming treatment (2) is an aqueous-phase reforming (APR) . 9. The method according to any one of claims 1 to 8, cha r a c t e r i z e d in that the aqueous- phase reforming (APR) is carried out at temperature of 200 - 250 °C and under pressure of 30 - 34 bar. 10. The method according to any one of claims 1 to 9, cha r a c t e r i z e d in that the biomass is a lignocellulosic based biomass. 11. The method according to any one of claims 1 to 10, cha r a c t e r i z e d in that the biomass has been treated by means of at least one process step which is selected from the group comprising a gasifi cation, Fischer-Tropsch (FT) reaction of syngas, py rolysis, bio-oil refining and their combinations. 12. The method according to any one of claims 1 to 11, cha r a c t e r i z e d in that the side water fraction (1) comprises 1 - 40 % by volume organic com pounds . 13. The method according to any one of claims 1 to 12, cha r a c t e r i z e d in that the hydrogen (5) may be recirculated to the thermochemical treat- ment to adjust H2/CO ratio or to improve hydrotreat ment . 14. An apparatus for treating a side water fraction (1) which comprises at least one undesired compound and which is formed in a thermochemical treatment of biomass, cha r a c t e r i z e d in that the apparatus comprises - at least one reforming treatment device (12) in which the side water fraction (1) comprising at least one undesired organic compound is treated in order to convert the organic compound into at least hydrogen (5) and optionally also other com pounds (6) selected from the group comprising or ganic compounds, hydrocarbons, carbondioxide, carbonmonoxide and their combinations, and - Ni/NiAl204 catalyst (3) which is arranged inside the reforming treatment device (12) for catalyz ing the reforming treatment (2) . 15. The apparatus according to claim 14, cha r a c t e r i z e d in that the reforming treatment device (12) is an aqueous-phase reforming (APR) reac tor . 16. A use of the method according to any one of claims 1 to 13, cha r a c t e r i z e d in that the method is used in the aqueous-phase reforming, in the production of biofuels, in the treatment of the side water fraction after Fischer-Tropsch (FT) reaction, in the treatment of the side water fraction after bio-oil refining, in the treatment of the side water fraction after pyrolysis and/or its post-process, in the treat ment of the water fraction comprising at least organic compound, or their combinations. |
TION
FIELD
The application relates to a method defined in claim 1 and an apparatus defined in claim 14 for treating a side water fraction. Further, the applica tion relates to a use of the method defined in claim 16.
BACKGROUND
Known from the prior art is to convert bio mass to biofuels by thermochemical routes such as by a gasification and Fischer-Tropsch (FT) reaction. Also different side fractions form in these processes.
Further, known from the prior art is to treat different feedstocks comprising organic compounds in an aqueous-phase reforming (APR) process. Further, it is known that different catalysts can be used in this process.
The aqueous-phase reforming (APR) , such as operating conditions, catalysts and reactor designs, have been studied in the art. For instance, different feedstocks, temperatures, pressures and space veloci- ties have been tested for APR over numerous catalysts, mainly platinum- and nickel-based in form of parti cles. These catalysts have been prepared with differ ent supports and metal dopants to enhance the perfor mance of the catalysts. However, product selectivity and durability of the catalysts are questionable. Fur thermore, few reactor designs have been tested for APR, with a predominant use of tubular packed-bed re actors. Recently, intensified reactors have been con sidered to improve mass transport in APR, and conse- quently, increase the product efficiency. Although platinum-washcoated microchannels and membrane reac- tors enhance the performance, catalyst loading and re placement are significant barriers for scale up appli cations. Further, noble metal-based catalysts are ex pensive and economically inefficient in large scales.
OBJECTIVE
The objective is to disclose a new type meth od and apparatus for treating water fractions derived from biorefineries. Further, the objective is to dis close a new type method and apparatus for producing hydrogen from the aqueous solutions derived from bio refineries. Further, the objective is to disclose an improved method and apparatus for treating water frac tions in an aqueous-phase reforming. Further, the ob jective is to produce a new type catalyst to be used in the aqueous-phase reforming. Further, the objective is to prepare a new type catalyst. Further, the objec tive is to disclose a catalyst composition for coating a substrate.
SUMMARY
The method and apparatus and use are charac terized by what are presented in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are included to provide a further understanding of the invention and constitutes a part of this specification, illus trate some embodiments of the invention and together with the description help to explain the principles of the invention. In the drawings:
Fig. 1 is a flow chart illustration of a method and an apparatus according to one embodiment, and Fig. 2 shows results from one example carried out according to one method embodiment.
DETAILED DESCRIPTION
In a method for treating a side water frac tion (1) which comprises at least one undesired com pound and which is formed in a thermochemical treat ment of biomass, the side water fraction (1) compris ing at least one undesired organic compound is treated by means of a reforming treatment (2) in order to con vert the organic compound into at least hydrogen (5) and optionally also other compounds (6) selected from the group comprising organic compounds, such as modi fied organic compounds, hydrocarbons, carbondioxide, carbonmonoxide and their combinations, and the reform ing treatment (2) is catalyzed by Ni/NiAl 2 0 4 catalyst (3), preferably Ni/NiAl 2 0 4 washcoat catalyst.
An apparatus for treating a side water frac tion (1) which comprises at least one undesired com pound and which is formed in a thermochemical treat ment of biomass can comprise at least one reforming treatment device (12) in which the side water fraction (1) comprising at least one undesired organic compound is treated in order to convert the organic compound into at least hydrogen (5) and optionally also other compounds (6) selected from the group comprising or ganic compounds, such as modified organic compounds, hydrocarbons, carbondioxide, carbonmonoxide and their combinations, and Ni/NiAl 2 0 4 catalyst (3) , preferably Ni/NiAl 2 0 4 washcoat catalyst, which is arranged inside the reforming treatment device (12) for catalyzing the reforming treatment (2) .
One embodiment of the method and the apparatus is shown in Fig 1.
In this context, the biomass means any bio mass. In one embodiment, the biomass is a lignocellu- losic based biomass. Preferably, the biomass has been treated by converting into biofuels. The biomass may be converted into the biofuels by thermochemical routes such as by a gasification and Fischer-Tropsch (FT) reaction of syngas or other feedstock, or by a pyrolysis and bio-oil reforming. In one embodiment, the biomass has been treated by means of at least one process step which is selected from the group compris ing the gasification, Fischer-Tropsch (FT) reaction of syngas, pyrolysis, bio-oil refining and their combina tions. In one embodiment, the biomass has been treated by means of the gasification and/or the Fischer- Tropsch (FT) reaction of syngas. In one embodiment, the biomass has been treated by means of the pyrolysis and/or the bio-oil refining. In one embodiment, the side water fraction (1) is formed in the Fischer- Tropsch reaction or in the bio-oil refining.
In this context, the side water fraction (1) means any water fraction, biorefinery water fraction, water based side fraction or water based residue frac tion, in which fraction may be any fraction, separated fraction, flow, stream, outflow or their combination. The side water fraction may comprise at least one harmful organic compound, such as hydrocarbon, oxygen ated hydrocarbon or other organic compound or the like, for example alcohols, aldehydes, ketones, acids, aliphatic, aromatic and cyclic hydrocarbons. In one embodiment, the side water fraction comprises at least one organic compound, e.g. MeOH, organic compound with longer carbon chain or other compound. In one embodi ment, the side water fraction comprises at least MeOH. In one embodiment, the side water fraction comprises organic compound with longer carbon chain, such as al cohol, ketone, aldehyde and/or organic acid. In one embodiment, the side water fraction comprises 1 - 40 % by volume organic compounds, e.g. organic hydrocarbons or other organic compounds. In one embodiment, the side water fraction comprises over 5 % by volume, preferably 5 - 40 % by volume, more preferably 5 - 20 % by volume, organic compounds. In one embodiment, the side water fraction comprises 1 - 10 % by volume or ganic compounds.
In one embodiment, the Ni/NiAl 2 0 4 catalyst (3) is arranged in the form of a film, preferably a thin film, onto a substrate. The substrate can be formed from a metal material or a ceramic material or other suitable material. In one embodiment, the substrate can be a wall, reactor wall, static mixer, mesh, fi bres, fillers or other suitable substrate which are formed from the metal or ceramic material, or for ex ample, open cell foams which are formed from the ce ramic material.
In one embodiment, the Ni/NiAl 2 0 4 catalyst is Ni/NiAl 2 0 4 washcoat catalyst, more preferably Ni/NiAl 2 0 4 spinel washcoat catalyst, wherein the Ni/NiAl 2 0 4 is as a thin washcoat layer on the substrate, such as on the metal or ceramic surface of the substrate.
In one embodiment, the washcoat catalyst can be formed by preparing a catalytically active washcoat composition from a carrier material, preferably with a high surface area, e.g. aluminium oxide based carrier material, and one or more catalyst agents, e.g. met als, and by arranging the formed catalytically active washcoat composition onto the substrate, such as the metal or ceramic structure.
In one embodiment, Ni content of the Ni/NiAl 2 0 4 catalyst (3) is 8 - 20 wt%. In one embodi ment, Ni content of the Ni/NiAl 2 0 4 catalyst is 8 - 15 wt%, in one embodiment 10 - 14 wt%, and in one embodi ment about 11 - 13 wt%.
In one embodiment, the Ni/NiAl 2 0 4 catalyst (3) is prepared such that a catalyst agent, e.g. Ni, is impregnated, e.g. by an incipient wetness impregnation method, to a carrier material, e.g. boehmite, to form a catalytic material. Ni catalyst agent can be a Ni- precursor such as nickel nitrate or other precursor. The resulting catalytic material, e.g. in form of pow der, is dried and calcined, for example to transform nickel nitrate/boehmite into nickel oxide/boehmite . A slurry is prepared. In one embodiment, the slurry is prepared by mixing the resulting catalytic material with a binder, an acid and water. The slurry is ar ranged by washcoating onto a substrate, such as a met al or ceramic substrate, and the washcoated substrate is thermally treated, e.g. by means of a high tempera ture calcination. Then a thin layer of Ni/NiAl 2 0 4 can be formed onto the substrate.
In one embodiment, the Ni/NiAl 2 0 4 catalyst (3) is prepared such that Ni-precursors are impregnated into a boehmite carrier material to form a catalytic material, and the catalytic material, preferably in a powder form, is dried and calcinated, and a slurry comprising at least the catalytic material, and pref erably at least suitable liquid, is prepared and stirred, and the substrate is washcoated with the slurry, and the washcoated substrate is thermally treated, such as dried, calcinated and treated by re duction. In one embodiment, the catalytic material is dried by means of under pressure or vacuum drying or their combination. In one embodiment, the catalytic material is dried under vacuum. In one embodiment, the catalytic material is calcinated at a temperature of 450 - 550 °C, preferably at 490 - 510 °C. In the cal cination, Ni-precursor can be converted, e.g. from nickel nitrate to nickel oxide. In one embodiment, the slurry comprises at least the catalytic material and water, preferably ion-exchanged water. Further, the slurry may comprise a suitable solution and acid, such as HN0 3 , and a binder. In one embodiment, the sub strate is pre-treated and calcinated before the wash coating. In one embodiment, the formed washcoated sub strate is dried at a temperature of 400 - 600 °C, preferably 450 - 550 °C, for a sufficient time, e.g. about 3 - 7 min, such as about 5 min. In one embodi ment, the washcoated substrate is slowly dried by air flow at ambient temperature and pressure before the above flash-drying. In one embodiment, the washcoated substrate is calcinated at a temperature of 700 - 900 °C, preferably 750 - 850 °C, for a sufficient time, e.g. about 1.5 - 2.5 hours, such as about 2 hours, to fix the catalytic material on the substrate. In one embodiment, the formed washcoat catalyst is treated by reduction at a temperature of 350 - 450 °C, preferably 370 - 430 °C, with a sufficient H2:N2 ratio. In one embodiment, H2:N2 ratio can be about 1.
In one embodiment, the reforming treatment (2) is a 3-phase reforming treatment. In one embodi ment, the reforming treatment (2) is an aqueous-phase reforming (APR) . In one embodiment, the aqueous-phase reforming (APR) is carried out at temperature which is 200 - 250 °C, preferably about 230 °C, and under pres sure which is 30 - 34 bar, preferably 32 bar. In one embodiment, an aqueous solution which comprises 0.1 - 10 wt%, preferably 3 - 7 wt%, organic compounds and which is formed from the side water fraction (1) is fed to the aqueous-phase reforming (APR) . In one em bodiment, the side water fraction (1) is diluted with water before the feeding to the aqueous-phase reform ing (APR) . In this context, the aqueous-phase reform ing means any aqueous-phase reforming, catalytic aque ous-phase reforming or the like.
In the reforming treatment (2) at least hy drogen (5) and optionally some other compounds (6), such as organic compounds, hydrocarbons, carbondioxide and/or carbonmonoxide are formed. Preferably, at least hydrogen (5) is formed. In one embodiment, also car- bondioxide and carbonmonoxide can be formed during the reforming treatment (2) . In one embodiment, hydrogen and carbondioxide are formed. In one embodiment, also some hydrocarbons, e.g. methane, ethane or other hy drocarbon, can be formed during the reforming treat ment (2) . In one embodiment, methane is formed. In one embodiment, also some organic compounds, e.g. alcohol, ketones, aldehydes and organic acids or other organic compounds, can be formed during the reforming treat ment (2) . In one embodiment, at least a part of the reforming treatment products are gaseous products. In one embodiment, at least a part of the reforming treatment products are liquid products. In one embodi ment, the reforming treatment products are mainly gas eous products. In one embodiment, the reforming treat ment products are mainly liquid products. In one em bodiment, the gaseous reforming treatment products can comprise at least CO, C0 2 , CH 4 , C 2 H 6 , C 2 H 4 and/or C 3 H 6 . In one embodiment, the liquid reforming treatment products can comprise alcohol, ketones, aldehydes and/or organic acids.
In one embodiment, the method comprises more than one reforming treatment step or device (12), such as aqueous-phase reforming (APR) step or reactor. In one embodiment, the apparatus comprises more than one reforming treatment device (12), such as aqueous-phase reforming reactor.
In one embodiment, the hydrogen (5) is fed back to the thermochemical treatment, e.g. to the Fischer-Tropsch (FT) unit, to adjust H 2 /CO ratio. In one embodiment, the hydrogen (5) is fed back to the bio-oil refining unit for hydrotreatment, e.g. to im prove hydrotreatment of pyrolysis oils, e.g. hydro genation, hydrodeoxygenation or the like. In one embodiment, the apparatus comprises at least one feed inlet for supplying the side water fraction (1) to the reforming treatment device (12) . The feed inlet of the side water fraction may be any suitable inlet known per se, e.g. pipe, port or the like. In one embodiment, the apparatus comprises at least one feeding device. In this context, the feeding device can be any feeding device, equipment or other suitable device for feeding the side water fraction (1) to the reforming treatment device (12) . In one em bodiment, the feeding device is selected from the group comprising pump, compressor, tube, pipe, other suitable feeding device and their combinations. In one embodiment, the apparatus comprises at least one addi- tion device for adding the catalyst (3) to the reform ing treatment device (12) . The addition device may be any suitable addition device. In one embodiment, the apparatus comprises at least one product outlet for supplying hydrogen (5) or other compound stream (6), such as organic compound, hydrocarbons, carbondioxide and/or carbonmonoxide stream or product out from the reforming treatment device (12) . The product outlet may be any suitable outlet known per se, e.g. pipe, outlet port or the like. Any suitable reforming treat- ment device (12), e.g. aqueous-phase reforming reac tor, known per se can be used as the reforming device in the apparatus .
In one embodiment, the reforming treatment device (12) is an aqueous-phase reforming reactor.
In one embodiment, the apparatus comprises more than one reforming treatment devices (12) . In one embodiment, at least two reforming treatment devices are arranged in parallel. In one embodiment, at least two reforming treatment devices are arranged sequen tially. In one embodiment, the method is based on a continuous process. In one embodiment, the apparatus is a continuous apparatus. In one embodiment, the method is based on a batch process. In one embodiment, the apparatus is a batch apparatus.
In one embodiment, the apparatus and the method is used and utilized in the aqueous-phase re forming, in the production of biofuels, in the treat ment of the side water fraction after a Fischer- Tropsch (FT) reaction, in the treatment of the side water fraction after bio-oil refining, in the treat ment of the side water fraction after pyrolysis and/or its post-process, in the treatment of the water frac tion comprising at least organic compound, or their combinations .
Thanks to the invention the different water based streams with harmful organic compounds can be treated effectively. High conversion rates and hydro gen selectivity can be obtained when the reforming treatment, such as the aqueous-phase reforming, is catalyzed with Ni/NiAl 2 0 4 catalyst. The performance of this catalyst is remarkably superior compared to nick el-based catalysts in a packed-bed tubular reactor. The improvement derives from the high activity of the catalyst and the reduction of the internal mass trans fer limitations. Further, this catalyst represents a much less expensive alternative to the traditionally used platinum-based catalysts.
The method and apparatus offers a possibility to treat different water based side and residue streams easily, and energy- and cost-effectively. The present invention provides an industrially applicable, simple and affordable way to treat the water based streams. The water based streams can be treated under mild conditions, such as at low temperature and under medium pressure. Further, no evaporation stages are needed. The method and apparatus are easy and simple to realize in connection with production processes of biofuels, also in a small scale process. Then more en vironmentally friendly biofuel production process can be provided. Further, the biofuel production process can be optimized by utilizing the hydrogen produced in the reforming treatment device. Further, an amount of waste water for disposal can be decreased.
EXAMPLES
Example 1
Figure 1 presents the method and also the ap paratus for treating a side water fraction (1) derived from a biorefinery.
The side water fraction (1) has been formed in a thermochemical treatment of lignocellulosic based biomass. The lignocellulosic based biomass can be treated by converting into the biofuels by means of the thermochemical routes such as by a gasification and Fischer-Tropsch (FT) reaction of syngas or other feedstock, or by a pyrolysis and bio-oil reforming. The side water fraction (1) has been formed in the Fischer-Tropsch reaction or in the bio-oil refining.
The side water fraction (1) comprises at least one undesired organic compound. The side water fraction (1) may comprise 1 - 40 % by volume organic compounds. The apparatus comprises at least one re forming treatment device (12), in this embodiment an aqueous-phase reforming (APR) reactor, in which the side water fraction (1) is treated by a reforming treatment (2) in order to convert the organic compound into at least hydrogen (5) and optionally also other compounds (6), such as organic compounds, hydrocar bons, carbondioxide and/or carbonmonoxide . Further, the method and apparatus comprise Ni/NiAl 2 0 4 catalyst (3) , preferably Ni/NiAl 2 0 4 spinel washcoat catalyst, which is arranged inside the reforming treatment de vice (12) for catalyzing the reforming treatment (2) . Preferably, the aqueous-phase reforming can be carried out at temperature of 200 - 250 °C and under pressure of 30 - 34 bar.
The Ni/NiAl 2 0 4 spinel washcoat catalyst (3) is arranged in the form of a film, preferably a thin lay er, onto a substrate, such as a metal substrate or a ceramic substrate. Preferably the Ni/NiAl 2 0 4 spinel washcoat catalyst (3) is prepared in a catalyst pre paring stage (4) . The Ni/NiAl 2 0 4 spinel washcoat cata lyst can be formed such that a Ni-precursor, e.g. nickel nitrate, is impregnated by an incipient wetness impregnation method to a boehmite carrier material to form a catalytic material. The resulting catalytic ma terial in form of powder is dried and calcined, for example to transform nickel nitrate/boehmite into nickel oxide/boehmite . A slurry comprising at least the catalytic material is prepared by mixing the re sulting catalytic material, for example with a binder, an acid and water. The slurry is arranged by washcoat ing onto a metal or ceramic substrate, and the wash- coated substrate is thermally treated, e.g. by means of drying, calcination and treatment by reduction.
Then a thin layer of Ni/NiAl 2 0 4 can be formed onto the substrate. Preferably, Ni content of the Ni/NiAl 2 0 4 spinel washcoat catalyst is 10 - 16 wt%.
The hydrogen (5) may be recirculated and fed back to the thermochemical treatment, e.g. to the
Fischer-Tropsch (FT) unit or to the bio-oil refining unit, to adjust H 2 /CO ratio or to improve hydrotreat ment of pyrolysis oils. Example 2
The aqueous-phase reforming (APR) was studied with different catalysts in a laboratory scale pro cess. The main problems of the APR were mass transfer limitations, and the low activity and stability of the catalysts. Both external and internal mass transfers were limited in a 3-phase system of the APR, with sol id catalyst, liquid feedstock and gaseous products. This limitation negatively affected the conversion of reactants and the selectivity towards desired prod ucts. Further, catalysts with low activity, such as typical, previous known Ni-based and Ce-promoted cata lysts, decreased the conversion and selectivity. Plat inum-based catalysts commonly exhibit good performance in terms of activity. However, the noble metal-based catalysts are expensive and economically inefficient in large scales. Furthermore, low stability results in catalyst deactivation by sintering or leaching of the active metal due to, for example, the nature of the feedstock or the hydrothermal, high pressure operating conditions. APR feedstocks are frequently a highly di luted mixture of organic compounds, which exact compo sition is frequently unknown. Therefore, to design an active, selective and stable catalyst to convert such mixture constitutes a challenging task.
The different catalysts were studied in the APR process in which the feedstock comprised methanol. Surprisingly, Ni/NiAl 2 0 4 spinel washcoat catalyst was found to overcome these problems. The mass transfer limitations can be decreased by means of the inexpen sive and durable Ni/NiAl 2 0 4 spinel washcoat catalyst which actively and selectively converts the feedstock into targeted products in the operating conditions of the APR process. Example 3
In this example, a side water fraction formed from lignocellulosic biomass in a Fischer-Tropsch re- actor was treated with the catalyst in the aqueous- phase reforming (APR) reactor according to the process of Fig. 1. The results are presented in Fig. 2.
The aqueous-phase reforming (APR) was carried out at about 230 °C under pressure of about 32 bar. The feedstock of the APR was an aqueous solution, formed from the side water fraction, with 5 wt% organ ic compounds, especially MeOH. The treatment was car ried out with the Ni/NiAl 2 0 4 spinel washcoat catalyst in the aqueous-phase reforming (APR) reactor. Further, the treatment was carried out with two comparative catalysts, NiAl-catalyst and NiCeAl-catalyst, in the aqueous-phase reforming (APR) reactor. The Ni/NiAl 2 0 4 spinel washcoat catalyst comprised about 10 - 13 wt%
Ni. NiAl-catalyst and NiCeAl-catalyst comprised about 10 - 13 wt% Ni on y-Al 2 0 3 support. Further, NiCeAl- catalyst was Ce-promoted.
The results are presented in Fig. 2. Y (%) means yield. CtG is calculated as total mol of carbon- containing gaseous products divided by the mol of car- bon-containing compounds in the feeding solution.
It was observed surprisingly that the Ni/NiAl 2 0 4 spinel washcoat catalyst was more highly ac tive in the aqueous phase reforming (APR) when com pared to the comparative catalysts. The performance of the Ni/NiAl 2 0 4 spinel washcoat catalyst was remarkably superior compared to nickel-based catalysts. High con version rates and hydrogen selectivity could be ob tained when the aqueous-phase reforming was catalyzed with the Ni/NiAl 2 0 4 spinel washcoat catalyst. The im provement derives from the high activity of the cata- lyst and the reduction of the internal mass transfer limitations in the thin layer of the washcoat.
Example 4
In this example, the Ni/NiAl 2 0 4 spinel wash- coat catalyst with 13 wt% Ni content was prepared. This catalyst was used in the tests of Example 3.
Ni-metal precursor such as nickel nitrate was impregnated by means of an incipient wetness impregna tion into a boehmite carrier material in a powder form in order to form a catalytic material. The catalytic material in a powder form was dried by means of a vac uum drying and calcinated at 500 °C to convert nickel nitrate/boehmite into nickel oxide/boehmite . After that a slurry composition comprising 44.4 wt% catalyt ic material, 2.01 wt% Disperal 10 solution, 1.05 wt% HN0 3 and 52.54 wt% ion-exchanged water was prepared and stirred by means of a magnetic stirring at 700 rpm for 24 hours. A metal substrate was washcoated with the slurry. The substrate was pre-treated by an ace tone/isopropanol wash and water rinsing, and the sub strate was calcinated at 900 °C for 6 hours before the washcoating. The washcoated substrate was dried by a slow drying with hot air flow and by a fast drying at 500 °C for 5 min. Further, calcination at 800 °C for 2 hours was made. After that, catalyst reduction was made at 400 °C in which H2:N2 is about 1. Then the thin layer of Ni/NiAl 2 0 4 spinel washcoat catalyst had been prepared on the substrate. It was observed that the strong washcoat can be provided on the metal sur face of the substrate.
The devices and equipments of the aqueous- phase reforming process used in these examples are known per se in the art, and therefore they are not described in any more detail in this context. The method, apparatus and catalysts are suit able in different embodiments for treating different kinds of water fractions and streams.
The invention is not limited merely to the examples referred to above; instead many variations are possible within the scope of the inventive idea defined by the claims.
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