Method for producing catalysts and catalysts thereof

Abstract

The invention relates to a process to produce catalysts by powder injection moulding and the catalysts thereof, wherein the catalysts are made by preparing a ceramic formulation with temperature controlled rheological properties comprising catalytic components, heating the powder formulation up to at least the fluid state transition temperature, shaping a sample by injecting the fluid powder formulation into an injection mould followed by cooling the injected powder formulation below the fluid state transition temperature, de-binding the shaped sample, and sintering the shaped sample to form a ceramic catalyst. Alternatively the ceramic structure may be formed initially followed by a coating of the ceramic structure by one or more catalytic compounds.

1 - 19 . (canceled) 
   
   
       20 . Method for production of ceramic catalysts, the method comprising:
 preparing a ceramic formulation;   heating the powder formulation;   shaping a sample by injecting the fluid powder formulation into an injection mold followed by cooling the injected powder formulation;   de-binding the shaped sample; and   sintering the shaped sample,   wherein the prepared ceramic formulation has temperature controlled rheological properties and comprises a catalytic component, the formulation is heated up to at least the fluid state transition temperature and following the shaping of sample is cooled below the fluid state transition temperature before the de-binding and sintering steps to form a ceramic catalyst.   
   
   
       21 . Method for production of catalysts, the method comprising:
 preparing a ceramic support formulation;   heating the powder formulation;   shaping a sample by injecting the fluid powder formulation into an injection mold followed by cooling the injected powder formulation;   de-binding the shaped sample;   sintering the shaped sample to form a ceramic support structure,   wherein the prepared ceramic formulation has temperature controlled rheological properties, the formulation is heated up to at least the fluid state transition temperature and following the shaping of sample is cooled below the fluid state transition temperature before the de-binding and sintering steps; and   coating the surfaces of the ceramic support structure with one or more catalytic compounds.   
   
   
       22 . The method according to  claim 20 , wherein:
 the injection mold is provided with a number of pins extending across the internal space of the mold such that the formed catalyst obtains a number of through-going internal channels to obtain a voidage fraction ranging from 30% up to 90%; and   the dimensions and physical design of the internal walls defining the internal space of the injection molds are designed to form ceramic catalysts which are comparable in size and shape as present monoliths.   
   
   
       23 . The method according to  claim 22 , wherein the pins have a variable diameter, such as a tapering, in order to form channels with varying cross-sectional areas. 
   
   
       24 . The method according to  claim 22 , wherein the pins have at least one stepwise increase of the pin diameter in order to form internal through-going channels in the catalyst body with an abrupt stepwise increase of the diameter. 
   
   
       25 . The method according to  claim 20 , wherein the formulations comprise one or more catalyst powders, one or more binders, one or more lubricants, and one or more surfactants. 
   
   
       26 . The method according to  claim 25 , wherein the ceramic formulation comprises about 80 weight % ceramic oxides, about 15 weigh% paraffin wax, about 2 weight % polyethylene wax, about 2 weight % vegetable wax, and about 1 weight % cis-9-octadecenoic acid. 
   
   
       27 . The method according to  claim 26 , wherein the vegetable wax is Copernica cerifera. 
   
   
       28 . The method according to  claim 26 , wherein the fluid transition temperature is between room temperature to 150° C., between 40 to 130° C., from 60 to 110° C.; or from 80 to 100° C. 
   
   
       29 . The method according to  claim 26 , wherein the injection pressure is between 3 to 100 bar absolute. 
   
   
       30 . The method according to  claim 22 , wherein the pins form one or more through-going channels, and said channel(s) has/have a varying cross-sectional area along the longitudinal direction of the channel(s). 
   
   
       31 . The method according to  claim 30 , wherein the channels have one or more stepwise changes of the channel diameter. 
   
   
       32 . The method according to  claim 30 , wherein the catalyst is made of a catalytic ceramic oxide material. 
   
   
       33 . The method according to  claim 30 , wherein the catalyst is made of a ceramic oxide material coated with a catalytic material. 
   
   
       34 . The method according to  claim 30 , wherein the varying cross-sectional area is formed by a linear reduction of the internal diameter of the channel(s). 
   
   
       35 . The method according to  claim 30 , wherein:
 the internal channels may be given circular, elliptical, square, triangular, hexagonal, or other forms of the channels cross-sectional areas; and   the catalysts may be given channels which have a length from 0.1 mm to about 800 mm, alternatively from 5 mm to 150 mm, alternatively from 5 to 20 mm.   
   
   
       36 . The method according to  claim 32 , wherein the ceramic compound is a cobalt based oxide capable of catalytically aiding the decomposition of nitrogen oxides. 
   
   
       37 . The method according to  claim 36 , wherein:
 the cobalt based oxide comprises an active Co 2 AlO 4 -phase on a cerium oxide support;   the catalyst is a monolith with dimensions ranging from 25×25×10 mm to 200×200×100 mm, alternatively from 25×25×10 mm and 200×200 and 100 mm, or from 25×25×10 mm and 100×100 and 100 mm;   the through-going channels have a circular cross-section and their internal diameter are abrupt increased from 1.0 mm to 1.5 mm inside the catalyst body; and   the internal through-going channels are ordered in a hexagonal pattern.   
   
   
       38 . The method according to  claim 37 , wherein the catalyst produced is equipped with one or more protrusions and one or more complementary recessions enabling forming an interlocking grip when the monoliths are placed abutting each other. 
   
   
       39 . The method according to  claim 21 , wherein:
 the injection mold are provided with a number of pins extending across the internal space of the mold such that the formed catalyst obtains a number of through-going internal channels to obtain a voidage fraction ranging from 30% up to 90%; and   the dimensions and physical design of the internal walls defining the internal space of the injection molds are designed to form ceramic catalysts which are comparable in size and shape as present monoliths.   
   
   
       40 . The method according to  claim 21 , wherein the formulations comprise one or more catalyst powders, one or more binders, one or more lubricants, and one or more surfactants.