Ceramic substrate reduction catalysts are often used to reduce NOx from large-scale biomass combustion processes.
There are two different approaches to making ceramic reduction catalysts: either the whole substrate can be made from a mixture of materials which have catalytic properties, or the substrate itself is made from a support material and a catalytic coating is applied afterwards.
In the first type, the substrate usually consists of vanadium pentoxide, titania and tungsten. These homogenous substrates are ideal in situations where the flue gas contains abrasive particles, because the surface of the substrate can abrade without loss of activity.
In the second type, the substrate usually consists of cordierite. This is then coated with either a vanadium or zeolite catalyst.
As applications for ceramic substrate reduction catalysts are often large in scale, it is common practice to use multiple substrates to make a grid. The industry standard substrate size is 150mm high, 150mm wide with a range of lengths.
Whitebeam can supply either homogenous or coated ceramic reduction catalysts with a range of cell densities from 16 cells per square inch (cpsi) up to 200 cpsi. The optimum cell density is determined after considering any solid matter (e.g. ash) which is contained in the flue gas, as the size of the cells should be bigger than the size of the solids to avoid blockage.