Preparation method of denitration catalyst with wide operating temperature range for flue gas

Abstract

The invention discloses a preparation method and application of a denitration catalyst with wide operating temperature for flue gas, which utilizes an organic vanadium compound as a vanadium precursor, and titanium dioxide powder or titanium tungsten powder as a carrier, and is prepared by mechanical ball milling method and heat treatment to obtain a catalyst, which denitration of fixed source flue gas under wide temperature range. Compared with the existing arts, the present invention includes minor modifications to the traditional vanadium tungsten titanium catalyst system and adopts the mechanical ball milling method, the activity and resistance to sulfur and water poisoning are improved significantly, thus providing a preparation technology of SCR denitration powder catalyst which is green, highly efficient, low cost and simple in operation. Through the interaction of the organic vanadium precursor with the carrier, the vanadium surface atom concentration of the catalyst is higher, the species of polymeric vanadium is more, and the vanadium oxide is more easily reduced, thereby obtaining higher denitrification activity at low temperature. The denitration catalyst of the present invention has relatively higher activity at 200-450° C. while having good resistance to sulfur and water poisoning.

Claims

1. A preparation method of denitration catalyst with wide operating temperature range for flue gas, characterized in that: the preparation method comprises the steps of: initially mixing a titanium dioxide powder or a titanium tungsten powder as a carrier and an organic vanadium compound as a vanadium precursor, then adding to a ball mill tank for carrying out mechanical ball milling for 30-120 mins with a rotation speed of 20-80 rpm; and carrying out drying and roasting processes to obtain the SCR denitration catalyst powder with wide temperature range, wherein said drying process comprises the step of drying in an oven at 110° C. for 8 hours; and said roasting process comprises the steps of: roasting in a muffle furnace: first by a rapid temperature rise method in which a rapid temperature rise at room temperature at 10° C./min to 110° C. is carried out; then by a slow temperature rise method in which a slow temperature rise at 2° C./min to 300° C. is carried out; and by a rapid temperature rise method in which a rapid temperature rise at 10° C./min to 500° C. is carried out and maintain at 500° C. for 4 hours; and finally natural cooling with the muffle furnace to obtain a final product of SCR denitration catalyst with wide temperature range.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram showing a denitration efficiency of the catalyst in powdered form obtained in the embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(2) The present invention is described in further detail below with reference to specific embodiments.

Embodiment 1

(3) A preparation method of denitration catalyst with wide operating temperature range for flue gas

(4) Step 1: initially mixing of 98 g titanium tungsten powder and 3.4 g vanadium oxalate, then adding to a ball mill tank for the mechanical ball milling for 30 min with a rotation speed of 40 rpm to obtained a ball milled mixture;

(5) Step 2: taking out the ball milled mixture and drying at 110° C. for 8 hours, then roasting in an air atmosphere: at room temperature, rapid temperature rise at 10° C./min to 110° C.; slow temperature rise slow temperature rise at 2° C./min to 300° C.; rapid temperature rise at 10° C./min to 500° C. and maintain at 500° C. for 4 hours; and finally natural cooling with the muffle furnace to obtain a SCR denitration catalyst with wide operating temperature range in powdered form.

(6) FIG. 1 shows the results of denitration activity test of the catalyst. Test conditions: the catalyst powder is pressed into a tablet, crushed and sieved, catalyst particles of 50-100 mesh is selected for denitration activity evaluation, 1.0 g catalyst, NO 500 ppm, NH.sub.3 400 ppm, O.sub.2 5 vol. %, N.sub.2 balance, total flue gas flow rate is 1 L/min, gas airspeed GHSV 60,000 h.sup.−1 (standard condition).

(7) It can be seen from the test results that as the reaction temperature increases, the denitration efficiency of the vanadyl oxalate catalyst first increases and then remains at 80%, and the denitration efficiency is higher than that of the conventional ammonium metavanadate catalyst, the advantage is especially significant at the low temperature to reaction window (<300° C.).

Embodiment 2

(8) A preparation method of denitration catalyst with wide operating temperature range for flue gas

(9) Step 1: initially mixing of 98 g titanium tungsten powder and 6.0 g acetylacetonate vanadium, then adding to a ball mill tank for the mechanical ball milling for 40 min with a rotation speed of 30 rpm to obtained a ball milled mixture;

(10) Step 2: taking out the ball milled mixture and drying at 110° C. for 8 hours, then roasting in an air atmosphere: at room temperature, rapid temperature rise at 10° C./min to 110° C.; slow temperature rise slow temperature rise at 2° C./min to 300° C.; rapid temperature rise at 10° C./min to 500° C. and maintain at 500° C. for 4 hours; and finally natural cooling with the muffle furnace to obtain a SCR denitration catalyst with wide operating temperature range in powdered form.

(11) FIG. 1 shows the results of denitration activity test of the catalyst. Test conditions: the catalyst powder is pressed into a tablet and then crushed and sieved, catalyst particles of 50-100 mesh is selected for denitration activity evaluation, 1.0 g catalyst, NO 500 ppm, NH.sub.3 400 ppm, O.sub.2 5 vol. %, N.sub.2 balance, total flue gas flow rate is 1 L/min, gas airspeed GHSV 60,000 h.sup.−1 (standard condition).

(12) It can be seen from the test results that the denitration activity of the vanadium acetylacetonate catalyst is higher than that of other catalysts, and has excellent denitration performance.