Catalysed filter based on biosoluble fibers

Abstract

Catalyzed filter consisting of a filter body of bio-soluble fibers catalyzed with a catalyst comprising oxides of vanadium and titanium, wherein the total concentration of alkali metals in the filter body is less than 3000 ppm by weight and/or the total concentration of alkali earth metals in the filter body is less than 20% by weight.

Claims

1. Catalysed filter consisting of a filter body of bio-soluble fibers catalysed with a catalyst comprising oxides of vanadium and titanium, wherein total concentration of alkali metals is greater than zero, but less than 0.1% by weight and the total concentration of alkali earth metals in the filter body is greater than zero, but less than 10% by weight.

2. The catalysed filter of claim 1, wherein the bio-soluble fibers are selected from the group of calcium-magnesium-silicates.

3. A method of removal of particulate matter and nitrogen oxides, dioxins and carbon monoxide from gases comprising the step of utilizing the catalysed filter of claim 1 for the removal of particulate matter and at least one of nitrogen oxides, dioxins and carbon monoxide from gases.

4. A method of removal of particulate matter, dioxins and carbon monoxide from gases comprising the step of utilizing the catalysed filter of claim 2 for the removal of particulate matter and at least one of nitrogen oxides, dioxins and carbon monoxide from gases.

5. The method of claim 3, wherein the temperature of the gasses is less than 450 C.

6. The method of claim 4, wherein the temperature of the gasses is less than 450 C.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) Pursuant to the above findings and observations, the invention provides a catalysed filter consisting of a filter body of bio-soluble fibres catalysed with a catalyst comprising oxides of vanadium and titanium, wherein the total concentration of alkali metals in the filter body is less than 0.1% by weight and/or the total concentration of alkali earth metals in the filter body is less than 10% by weight.

(2) Suitable bio-soluble fibers for use in the catalysed filter according the invention are selected from the group of calcium-magnesium-silicates.

(3) In a further embodiment of the invention, the catalysed filter is used for the removal of particulate matter and at least one of nitrogen oxides, dioxins and carbon monoxide from gases.

(4) Temperature is believed to be a parameter influencing the release rate of the poison and consequently the deactivation rate of the catalytic filters.

(5) Thus, according to a further embodiment of the invention, the temperature of the gasses to be treated with the filter is less than 450 C.

(6) The table below reports chemical analysis of the bio-soluble ceramic filters used in the tests. All filters were impregnated with slurry containing the V/Ti catalyst active in the SCR reaction.

(7) Among the three different filters, only the one made of Fiber 1 reported good and stable SCR activity. The filters made of Fiber 2 and 3 reported deactivation during operation. The rate of deactivation was highly increased by operating the filters at temperatures >250 deg C.

(8) TABLE-US-00001 K Na Mg Ca Fiber 1 0.02 wt % 0.02 wt % 0.7 wt % 8 wt % Fiber 2 0.16 wt % 0.45 wt % 0.94 wt % 23.5 wt % Fiber 3 <200 wt ppm 0.354 wt % <130 wt ppm 410 wt ppm

(9) From the figures reported in the table above, it can be concluded that in order to manufacture a catalytic filter based on V/Ti catalyst and bio-soluble ceramic filters it is necessary to keep the total alkali concentration (i.e. K+Na) in the fibers <3000 wt ppm. Moreover, the total concentration of alkali earth metals is preferred to be <20 wt %.

(10) Fiber 2 and 3 did not meet the former requirement and are therefore believed to not be suitable for the production of catalytic ceramic filters for the removal of NOx and dioxins on V-based catalysts.