Catalyst for synergistic control of oxynitride and mercury and method for preparing the same

Abstract

Disclosed are a catalyst for synergistic control of oxynitride and mercury and a method for preparing the same. The catalyst includes the following components by mass percentage: a carrier: TiO2 72%-98.6%, active components: V2O5 0.1%-5%, WO3 1%-10%, Cr2O3 0.1%-5% and Nb2O5 0.1%-5%, and a co-catalyst of 0.1%-3%. The present invention can be used for reducing the oxynitrides in a flue gas, meanwhile oxidizing zero-valent mercury into bivalent mercury and then controlling the reactions, has relatively high denitration performance and also has high mercury oxidation performance; compared with current commercial SCR catalysts, the mercury oxidation rate of the catalyst is improved to a great extent, which can adapt to the requirements for mercury removal in China's coal-fired power plants, the conversion rate of SO2/SO3 is relatively low, and the catalyst has a better anti-poisoning ability, and is a new catalyst with a low cost and high performance.

Claims

1. A method for preparing a catalyst for synergistic control of oxynitride and mercury, wherein the method comprises the following steps: 1) drying TiO.sub.2 and use TiO.sub.2 as a carrier; 2) stirring ammonium metavanadate and ammonium metatungstate under 50° C.-70° C. to dissolve in an oxalic acid or tartaric acid solution to obtain a solution A with pH value less than 2; stirring chromic nitrate under 10-50° C. to dissolve in deionized water or tartaric acid to obtain a solution B; stirring niobium oxalate under 50-70° C. to dissolve in deionized water or tartaric acid to obtain a solution C; 3) stirring cupric nitrate under 10-50° C. to dissolve in deionized water or tartaric acid to obtain a solution D; or stirring ferric nitrate under 10-50° C. to dissolve in deionized water or tartaric acid to obtain a solution E; or stirring ammonium molybdate under 10-50° C. to dissolve in deionized water or tartaric acid to obtain a solution F; 4) mixing the solution A, solution B and solution C with one of the solution D, solution E and solution F to obtain an impregnating solution, immersing the carrier from step 1) into the impregnating solution, stirring evenly for ultrasound concussion, evaporating and stirring with water bath for 10-60 minutes, drying in the oven and then calcine under 400° C.-550° C. for 3-5 hours to obtain the catalyst for synergistic control of oxynitride and mercury.

2. The preparation method according to claim 1, wherein the drying in step 1) is drying under 105° C.-120° C. for 12 hours-24 hours.

3. The preparation method according to claim 1, wherein the ultrasound concussion time in step 4) is 10-60 minutes.

4. The preparation method according to claim 1, wherein the water bath temperature in step 4) is 70-90° C.

5. The preparation method according to claim 4, wherein the drying condition in oven in step 4) is drying under 105-120° C. for 12-24 hours.

Description

DESCRIPTION OF THE PREFERRED EMBODIMENT

(1) Technical solution to the present invention will be further described next with specific embodiments.

(2) Unless otherwise particularly specified, raw materials and equipment used in the present invention can be purchased from the market or are commonly used in this field, and, unless otherwise particularly specified, methods in the following examples are conventional methods in this field.

EXAMPLE 1

(3) 1) TiO.sub.2 (nanoscale anatase TiO.sub.2, commercially available, particle size less than 30 nm) was dried under 105° C. for 12 hours and used as a carrier;

(4) 2) Ammonium metavanadate and ammonium metatungstate were stirred under 50° C. to dissolve in oxalic acid solution to obtain a solution A with pH value less than 2; Chromic nitrate was stirred under 10° C. to dissolve in deionized water to obtain a solution B; Niobium oxalate was stirred under 50° C. to dissolve in deionized water to obtain a solution C;

(5) 3) Cupric nitrate was stirred under 10° C. to dissolve in deionized water to obtain a solution D;

(6) 4) The solution A, solution B and solution C were mixed with the solution D to obtain an impregnating solution, the carrier from step 1) was immersed into the impregnating solution, stirred evenly for ultrasound concussion with ultrasonic cleaner for 10 minutes, evaporated and stirred with water bath under 70° C. for 10 minutes, dried in the oven under 105° C. for 12 hours and then calcine under 400° C. for 5 hours to obtain a catalyst for synergistic denitration and mercury oxidation with V.sub.2O.sub.5, WO.sub.3, Cr.sub.2O.sub.3, Nb.sub.2O.sub.5 and CuO in the following mass percentage: carrier TiO.sub.2 98.6%, active component V.sub.2O.sub.5 0.1%, active component WO.sub.31%, active component Cr.sub.2O.sub.3 0.1%, active component Nb.sub.2O.sub.5 0.1% and co-catalyst CuO 0.1%. The prepared catalyst was grounded and sieved to obtain catalyst particles with particle size of 40-60 mesh.

(7) Test 1:

(8) 0.2 g catalyst particle prepared in example 1 was put into a catalyst denitration activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with inner diameter of 8 mm. O.sub.2/N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 were controlled and mixed via mass flowmeter, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 5% O.sub.2, 1000 ppmNO, 1000 NH.sub.3, 500 ppmSO.sub.2 and 10% H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−1, reaction temperature of 350° C. and NH.sub.3/NO as 1. Test gas composition with ULTRMAT 32 gas analyzer manufactured by SIEMENS and the denitration efficiency was 72%.

(9) 0.2 g catalyst particle prepared in example 1 was put into a catalyst mercury removal activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with inner diameter of 8 mm. Hg.sup.0/N.sub.2, O.sub.2/N.sub.2, HCl\N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 were controlled and mixed via mass flowmeter, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 100 μg/m.sup.3Hg.sup.0, 5% O.sub.2, 10 ppmHCl, 300 ppmNO, 50 ppmNH.sub.3, 500 ppmSO.sub.2 and 10% H.sub.2O, with N.sub.2 as balance gas, air speed of 300000h.sup.−1 and reaction temperature of 350° C. Mercury concentration was tested with EMP-2 portable mercury analyzer manufactured by NIC and the oxygenation rate of zero-valent mercury was 68%.

EXAMPLE 2

(10) 1) TiO.sub.2 (nanoscale anatase TiO.sub.2, commercially available, particle size less than 30 nm) was dried under 105° C. for 12 hours and used as a carrier;

(11) 2) Ammonium metavanadate and ammonium metatungstate were stirred under 50° C. to dissolve in tartaric acid solution to obtain a solution A with pH value less than 2;

(12) Chromic nitrate was stirred under 10° C. to dissolve in deionized water to obtain a solution B;

(13) Niobium oxalate was stirred under 50° C. to dissolve in deionized water to obtain a solution C;

(14) 3) Cupric nitrate was stirred under 30° C. to dissolve in tartaric acid to obtain a solution D;

(15) 4) the solution A, solution B and solution C were mixed with the solution D to obtain an impregnating solution, the carrier from step 1) was immersed into the impregnating solution, stirred evenly for ultrasound concussion with ultrasonic cleaner for 10 minutes, evaporated and stirred with water bath under 70° C. for 10 minutes, dried in the oven under 105° C. for 12 hours and then calcined under 400° C. for 5 hours to obtain a catalyst for synergistic denitration and mercury oxidation with V.sub.2O.sub.5, WO.sub.3, Cr.sub.2O.sub.3, Nb.sub.2O.sub.5 and CuO in the following mass percentage: carrier TiO.sub.2 92.4%, active component V.sub.2O.sub.5 0.1%, active component WO.sub.31%, active component Cr.sub.2O.sub.3 2.5%, active component Nb.sub.2O.sub.5 2.5% and co-catalyst CuO 1.5%. The prepared catalyst was grounded and sieved to obtain catalyst particles with particle size of 40-60 mesh.

(16) Test 2:

(17) 0.2 g catalyst particle prepared in example 2 was put into a catalyst denitration activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with inner diameter of 8 mm. O.sub.2/N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 were controlled and mixed via mass flowmeter, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 5% O.sub.2, 1000 ppmNO, 1000NH.sub.3, 500 ppmSO.sub.2 and 10%H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−1, reaction temperature of 350° C. and NH.sub.3/NO as 1. Gas composition was tested with ULTRMAT 32 gas analyzer manufactured by SIEMENS and the denitration efficiency was 75%.

(18) 0.2 g catalyst particle prepared in example 2 was put into a catalyst mercury removal activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with inner diameter of 8 mm. Hg.sup.0/N.sub.2, O.sub.2/N.sub.2, HCl\N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 were controlled and mixed via mass flowmeter, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 100 μg/m.sup.3Hg.sup.0, 5%O.sub.2, 10 ppmHCl, 300 ppmNO, 50 ppmNH.sub.3, 500 ppmSO.sub.2 and 10%H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−1 and reaction temperature of 350° C. Mercury concentration was tested with EMP-2 portable mercury analyzer manufactured by NIC and the oxygenation rate of zero-valent mercury was 70%.

EXAMPLE 3

(19) 1) TiO.sub.2 (nanoscale anatase TiO.sub.2, commercially available, particle size less than 30 nm) was dried under 105° C. for 12 hours and used as a carrier;

(20) 2) Ammonium metavanadate and ammonium metatungstate was stirred under 50° C. to dissolve in oxalic acid solution to obtain a solution A with pH value less than 2;

(21) Chromic nitrate was stirred under 10° C. to dissolve in deionized water to obtain a solution B;

(22) Niobium oxalate was stirred under 50° C. to dissolve in deionized water to obtain a solution C;

(23) 3) Cupric nitrate was stirred under 50° C. to dissolve in deionized water to obtain a solution D;

(24) 4) The solution A, solution B and solution C were mixed with the solution D to obtain an impregnating solution, the carrier from step 1) was immersed into the impregnating solution, stirred evenly for ultrasound concussion with ultrasonic cleaner for 10 minutes, evaporated and stirred with water bath under 70° C. for 10 minutes, dried in the oven under 105° C. for 12 hours and then calcined under 400° C. for 5 hours to obtain a catalyst for synergistic denitration and mercury oxidation with V.sub.2O.sub.5, WO.sub.3, Cr.sub.2O.sub.3, Nb.sub.2O.sub.5 and CuO in the following mass percentage: carrier TiO.sub.2 85.9%, active component V.sub.2O.sub.5 0.1%, active component WO.sub.31%, active component Cr.sub.2O.sub.3 5%, active component Nb.sub.2O.sub.5 5% and co-catalyst CuO3%. The prepared catalyst was grounded and sieved to obtain catalyst particles with particle size of 40-60 mesh.

(25) Test 3

(26) 0.2 g catalyst particle prepared in example 3 was put into a catalyst denitration activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with inner diameter of 8 mm. O.sub.2/N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 were controlled and mixed via mass flowmeter, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 5% O.sub.2, 1000 ppmNO, 1000NH.sub.3, 500 ppmSO.sub.2 and 10% H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−, reaction temperature of 350° C. and NH.sub.3/NO as 1. Gas composition was tested with ULTRMAT 32 gas analyzer manufactured by SIEMENS and the denitration efficiency was 79%.

(27) 0.2 g catalyst particle prepared in example 3 was put into a catalyst mercury removal activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with inner diameter of 8 mm. Hg.sup.0/N.sub.2, O.sub.2/N.sub.2, HCl\N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 were controlled and mixed via mass flowmeter, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 100 μg/m.sup.3Hg.sup.0, 5% O.sub.2, 10 ppmHCl, 300 ppmNO, 50 ppmNH.sub.3, 500 ppmSO.sub.2 and 10% H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−1 and reaction temperature of 350° C. Mercury concentration was tested with EMP-2 portable mercury analyzer manufactured by NIC and the oxygenation rate of zero-valent mercury was 73%.

EXAMPLE 4

(28) 1) TiO.sub.2 (nanoscale anatase TiO.sub.2, commercially available, particle size less than 30 nm) was tried under 110° C. for 18 hours and used as a carrier;

(29) 2) Ammonium metavanadate and ammonium metatungstate were stirred under 60° C. to dissolve in oxalic acid solution to obtain a solution A with pH value less than 2;

(30) Chromic nitrate was stirred under 30° C. to dissolve in deionized water to obtain a solution B;

(31) Niobium oxalate was stirred under 60° C. to dissolve in deionized water to obtain a solution C;

(32) 3) Ferric nitrate was stirred under 10° C. to dissolve in deionized water to obtain a solution E;

(33) 4) The solution A, solution B and solution C were mixed with the solution E to obtain an impregnating solution, the carrier from step 1) was immersed into the impregnating solution, stirred evenly for ultrasound concussion with ultrasonic cleaner for 30 minutes, evaporated and stirred with water bath under 80° C. for 30 minutes, dried in the oven under 110° C. for 18 hours and then calcined under 475° C. for 4 hours to obtain a catalyst for synergistic denitration and mercury oxidation with V.sub.2O.sub.5, WO.sub.3, Cr.sub.2O.sub.3, Nb.sub.2O.sub.5 and Fe.sub.2O.sub.3 in the following mass percentage:

(34) carrier TiO.sub.2 92.2%, active component V.sub.2O.sub.5 2.5%, active component WO.sub.35%, active component Cr.sub.2O.sub.3 0.1%, active component Nb.sub.2O.sub.5 0.1% and co-catalyst Fe.sub.2O.sub.3 0.1%. The prepared catalyst was grounded and sieved to obtain catalyst particles with particle size of 40-60 mesh.

(35) Test 4

(36) 0.2 g catalyst particle prepared in example 4 was put into a catalyst denitration activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with inner diameter of 8 mm. O.sub.2/N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 were controlled and mixed via mass flowmeter, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 5% O.sub.2, 1000 ppmNO, 1000 NH.sub.3, 500 ppmSO.sub.2 and 10%H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−, reaction temperature of 350° C. and NH.sub.3/NO as 1. Gas composition was tested with ULTRMAT 32 gas analyzer manufactured by SIEMENS and the denitration efficiency was 83%.

(37) 0.2 g catalyst particle prepared in example 4 was put into a catalyst mercury removal activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with inner diameter of 8 mm. Hg.sup.0/N.sub.2, O.sub.2/N.sub.2, HCl\N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 was controlled and mixed via mass flowmeter, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 100 μg/m.sup.3Hg.sup.0, 5% O.sub.2, 10 ppmHCl, 300 ppmNO, 50 ppmNH.sub.3, 500 ppmSO.sub.2 and 10% H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−1 and reaction temperature of 350° C. Mercury concentration was tested with EMP-2 portable mercury analyzer manufactured by NIC and the oxygenation rate of zero-valent mercury was 79%.

EXAMPLE 5

(38) 1) TiO.sub.2 (nanoscale anatase TiO.sub.2, commercially available, particle size less than 30 nm) was dried under 110° C. for 18 hours and used as a carrier;

(39) 2) Ammonium metavanadate and ammonium metatungstate were stirred under 60° C. to dissolve in tartaric acid solution to obtain a solution A with pH value less than 2;

(40) Chromic nitrate was stirred under 30° C. to dissolve in deionized water to obtain a solution B;

(41) Niobium oxalate was stirred under 60° C. to dissolve in deionized water to obtain a solution C;

(42) 3) Ferric nitrate was stirred under 30° C. to dissolve in tartaric acid to obtain a solution E;

(43) 4) The solution A, solution B and solution C were mixed with the solution E to obtain an impregnating solution, the carrier from step 1) was immersed into the impregnating solution, stirred evenly for ultrasound concussion with an ultrasonic cleaner for 30 minutes, evaporated and stirred with water bath under 80° C. for 30 minutes, dried in the oven under 110° C. for 18 hours and then calcined under 475° C. for 4 hours to obtain a catalyst for synergistic denitration and mercury oxidation with V.sub.2O.sub.5, WO.sub.3, Cr.sub.2O.sub.3, Nb.sub.2O.sub.5 and Fe.sub.2O.sub.3 in the following mass percentage: carrier TiO.sub.2 86%, active component V.sub.2O.sub.5 2.5%, active component WO.sub.35%, active component Cr.sub.2O.sub.3 2.5%, active component Nb.sub.2O.sub.5 2.5% and co-catalyst Fe.sub.2O.sub.3 1.5%. The prepared catalyst was grounded and sieved to obtain catalyst particles with particle size of 40-60 mesh.

(44) Test 5

(45) 0.2 g catalyst particle prepared in example 5 was put into a catalyst denitration activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with an inner diameter of 8 mm. O.sub.2/N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 were controlled and mixed via mass flowmeter, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 5% O.sub.2, 1000 ppmNO, 1000NH.sub.3, 500 ppmSO.sub.2 and 10% H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−1, reaction temperature of 350° C. and NH.sub.3/NO as 1. Gas composition was tested with ULTRMAT 32 gas analyzer manufactured by SIEMENS and the denitration efficiency was 86%.

(46) 0.2 g catalyst particle prepared in example 5 was put into a catalyst mercury removal activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with an inner diameter of 8 mm. Hg.sup.0/N.sub.2, O.sub.2/N.sub.2, HCl\N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 were controlled and mixed via mass flowmeter, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 100 μg/m.sup.3Hg.sup.0, 5% O.sub.2, 10 ppmHCl, 300 ppmNO, 50 ppmNH.sub.3, 500 ppmSO.sub.2 and 10% H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−1 and reaction temperature of 350° C. Mercury concentration was tested with EMP-2 portable mercury analyzer manufactured by NIC and the oxygenation rate of zero-valent mercury was 84%.

EXAMPLE 6

(47) 1) TiO.sub.2 (nanoscale anatase TiO.sub.2, commercially available, particle size less than 30 nm) was dried under 110° C. for 18 hours and used as a carrier;

(48) 2) Ammonium metavanadate and ammonium metatungstate were stirred under 60° C. to dissolve in oxalic acid solution to obtain a solution A with pH value less than 2;

(49) Chromic nitrate was stirred under 30° C. to dissolve in deionized water to obtain a solution B;

(50) Niobium oxalate was stirred under 60° C. to dissolve in deionized water to obtain a solution C;

(51) 3) Ferric nitrate was stirred under 50° C. to dissolve in deionized water to obtain a solution E;

(52) 4) The solution A, solution B and solution C were mixed with the solution E to obtain an impregnating solution, the carrier from step 1) was immersed into the impregnating solution, stirred evenly for ultrasound concussion with ultrasonic cleaner for 30 minutes, evaporated and stirred with water bath under 80° C. for 30 minutes, dried in the oven under 110° C. for 18 hours and then calcined under 475° C. for 4 hours to obtain a catalyst for synergistic denitration and mercury oxidation with V.sub.2O.sub.5, WO.sub.3, Cr.sub.2O.sub.3, Nb.sub.2O.sub.5 and Fe.sub.2O.sub.3 in the following mass percentage: carrier TiO.sub.2 79.5%, active component V.sub.2O.sub.5 2.5%, active component WO.sub.35%, active component Cr.sub.2O.sub.3 5%, active component Nb.sub.2O.sub.5 5% and co-catalyst Fe.sub.2O.sub.3 3%. The prepared catalyst was grounded and sieved to obtain catalyst particles with particle size of 40-60 mesh.

(53) Test 6

(54) 0.2 g catalyst particle prepared in example 6 was put into a catalyst denitration activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with inner diameter of 8 mm. O.sub.2/N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 were controlled and mixed via mass flowmeter, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 5% O.sub.2, 1000 ppmNO, 1000 NH.sub.3, 500 ppmSO.sub.2 and 10% H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−, reaction temperature of 350° C. and NH.sub.3/NO as 1. Gas composition was tested with ULTRMAT 32 gas analyzer manufactured by SIEMENS and the denitration efficiency was 88%.

(55) 0.2 g catalyst particle prepared in example 6 was put into a catalyst mercury removal activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with inner diameter of 8 mm. Hg.sup.0/N.sub.2, O.sub.2/N.sub.2, HCl\N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 were controlled and mixed via mass flowmeter, deionized water was injected into a heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 100 μg/m.sup.3Hg.sup.0, 5% O.sub.2, 10 ppmHCl, 300 ppmNO, 50 ppmNH.sub.3, 500 ppmSO.sub.2 and 10% H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−1 and reaction temperature of 350° C. Mercury concentration was tested with EMP-2 portable mercury analyzer manufactured by NIC and the oxygenation rate of zero-valent mercury was 87%.

EXAMPLE 7

(56) 1) TiO.sub.2 (nanoscale anatase TiO.sub.2, commercially available, particle size less than 30 nm) was dried under 120° C. for 24 hours and used as a carrier;

(57) 2) Ammonium metavanadate and ammonium metatungstate were stirred under 70° C. to dissolve in oxalic acid solution to obtain a solution A with pH value less than 2;

(58) Chromic nitrate was stirred under 50° C. to dissolve in deionized water to obtain a solution B;

(59) Niobium oxalate was stirred under 70° C. to dissolve in deionized water to obtain a solution C;

(60) 3) Ammonium molybdate was stirred under 10° C. to dissolve in deionized water to obtain a solution F;

(61) 4) The solution A, solution B and solution C were mixed with the solution F to obtain an impregnating solution, the carrier from step 1) was immersed into the impregnating solution, stirred evenly for ultrasound concussion with ultrasonic cleaner for 60 minutes, evaporated and stirred with water bath under 90° C. for 60 minutes, dried in the oven under 120° C. for 24 hours and then calcined under 550° C. for 3 hours to obtain a catalyst for synergistic denitration and mercury oxidation with V.sub.2O.sub.5, WO.sub.3, Cr.sub.2O.sub.3, Nb.sub.2O.sub.5 and MoO.sub.3 in the following mass percentage: carrier TiO.sub.2 84.7%, active component V.sub.2O.sub.5 5%, active component WO.sub.310%, active component Cr.sub.2O.sub.3 0.1%, active component Nb.sub.2O.sub.5 0.1% and co-catalyst MoO.sub.30.1%. The prepared catalyst was grounded and sieved to obtain catalyst particles with particle size of 40-60 mesh.

(62) Test 7

(63) 0.2 g catalyst particle prepared in example 7 was put into a catalyst denitration activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with inner diameter of 8 mm. O.sub.2/N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 via mass flowmeter were controlled and mixed, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 5% O.sub.2, 1000 ppmNO, 1000NH.sub.3, 500 ppmSO.sub.2 and 10% H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−, reaction temperature of 350° C. and NH.sub.3/NO as 1. Gas composition was tested with ULTRMAT 32 gas analyzer manufactured by SIEMENS and the denitration efficiency was 90%.

(64) 0.2 g catalyst particle prepared in example 7 was into a catalyst mercury removal activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with inner diameter of 8 mm. Hg.sup.0/N.sub.2, O.sub.2/N.sub.2, HCl\N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 were controlled and mixed via mass flowmeter, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 100 μg/m.sup.3Hg.sup.0, 5% O.sub.2, 10 ppmHCl, 300 ppmNO, 50 ppmNH.sub.3, 500 ppmSO.sub.2 and 10% H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−1 and reaction temperature of 350° C.

(65) Mercury concentration was tested with EMP-2 portable mercury analyzer manufactured by NIC and the oxygenation rate of zero-valent mercury was 89%.

EXAMPLE 8

(66) 1) TiO.sub.2 (nanoscale anatase TiO.sub.2, commercially available, particle size less than 30 nm) was dried under 120° C. for 24 hours and used as a carrier;

(67) 2) Ammonium metavanadate and ammonium metatungstate were stirred under 70° C. to dissolve in tartaric acid solution to obtain a solution A with pH value less than 2;

(68) Chromic nitrate was stirred under 50° C. to dissolve in deionized water to obtain a solution B;

(69) Niobium oxalate was stirred under 70° C. to dissolve in deionized water to obtain a solution C;

(70) 3) Ammonium molybdate was stirred under 30° C. to dissolve in tartaric acid to obtain a solution F;

(71) 4) The solution A, solution B and solution C with the solution F were mixed to obtain an impregnating solution, the carrier from step 1) was immersed into the impregnating solution, stirred evenly for ultrasound concussion with ultrasonic cleaner for 60 minutes, evaporated and stirred with water bath under 90° C. for 60 minutes, dried in the oven under 120° C. for 24 hours and then calcined under 550° C. for 3 hours to obtain a catalyst for synergistic denitration and mercury oxidation with V.sub.2O.sub.5, WO.sub.3, Cr.sub.2O.sub.3, Nb.sub.2O.sub.5 and MoO.sub.3 in the following mass percentage: carrier TiO.sub.2 78.5%, active component V.sub.2O.sub.5 5%, active component WO.sub.310%, active component Cr.sub.2O.sub.3 2.5%, active component Nb.sub.2O.sub.5 2.5% and co-catalyst MoO.sub.31.5%. The prepared catalyst was grounded and sieved to obtain catalyst particles with particle size of 40-60 mesh.

(72) Test 8

(73) 0.2 g catalyst particle prepared in example 8 was put into a catalyst denitration activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with an inner diameter of 8 mm. O.sub.2/N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 were controlled and mixed via mass flowmeter, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 5% O.sub.2, 1000 ppmNO, 1000NH.sub.3, 500 ppmSO.sub.2 and 10% H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−, reaction temperature of 350° C. and NH.sub.3/NO as 1. Gas composition was tested with ULTRMAT 32 gas analyzer manufactured by SIEMENS and the denitration efficiency was 94%.

(74) 0.2 g catalyst particle prepared in example 8 was put into a catalyst mercury removal activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with inner diameter of 8 mm. Hg.sup.0/N.sub.2, O.sub.2/N.sub.2, HCl\N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 via mass flowmeter were controlled and mixed, deionized water was injected into a heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 100 μg/m.sup.3Hg.sup.0, 5% O.sub.2, 10 ppmHCl, 300 ppmNO, 50 ppmNH.sub.3, 500 ppmSO.sub.2 and 10% H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−1 and reaction temperature of 350° C. Mercury concentration was tested with EMP-2 portable mercury analyzer manufactured by NIC and the oxygenation rate of zero-valent mercury was 91%.

EXAMPLE 9

(75) 1) TiO.sub.2 (nanoscale anatase TiO.sub.2, commercially available, particle size less than 30 nm) was dried under 120° C. for 24 hours and used as a carrier;

(76) 2) Ammonium metavanadate and ammonium metatungstate were dried under 70° C. to dissolve in oxalic acid solution to obtain a solution A with pH value less than 2;

(77) Chromic nitrate was stirred under 50° C. to dissolve in deionized water to obtain a solution B;

(78) Niobium oxalate was stirred under 70° C. to dissolve in deionized water to obtain a solution C;

(79) 3) Ammonium molybdate was stirred under 50° C. to dissolve in deionized water to obtain a solution F;

(80) 4) The solution A, solution B and solution C were mixed with the solution F to obtain an impregnating solution, the carrier from step 1) was immersed into the impregnating solution, stirred evenly for ultrasound concussion with ultrasonic cleaner for 60 minutes, evaporated and stirred with water bath under 90° C. for 60 minutes, dried in the oven under 120° C. for 24 hours and then calcined under 550° C. for 3 hours to obtain a catalyst for synergistic denitration and mercury oxidation with V.sub.2O.sub.5, WO.sub.3, Cr.sub.2O.sub.3, Nb.sub.2O.sub.5 and MoO.sub.3 in the following mass percentage: carrier TiO.sub.2 72%, active component V.sub.2O.sub.5 5%, active component WO.sub.310%, active component Cr.sub.2O.sub.3 5%, active component Nb.sub.2O.sub.5 5% and co-catalyst MoO.sub.3 3%. The prepared catalyst was grounded and sieved to obtain catalyst particles with particle size of 40-60 mesh.

(81) Test 9

(82) 0.2 g catalyst particle prepared in example 9 was put into a catalyst denitration activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with inner diameter of 8 mm. O.sub.2/N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 via mass flowmeter were controlled and mixed, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 5% O.sub.2, 1000 ppmNO, 1000NH.sub.3, 500 ppmSO.sub.2 and 10% H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−, reaction temperature of 350° C. and NH.sub.3/NO as 1. Gas composition was tested with ULTRMAT 32 gas analyzer manufactured by SIEMENS and the denitration efficiency was 96%.

(83) 0.2 g catalyst particle prepared in example 9 was put into a catalyst mercury removal activity evaluation unit and activity evaluation was conducted in a fixed bed reactor with an inner diameter of 8 mm. Hg.sup.0/N.sub.2, O.sub.2/N.sub.2, HCl\N.sub.2, NO/N.sub.2, NH.sub.3/N.sub.2, SO.sub.2/N.sub.2 and N.sub.2 were controlled and mixed via mass flowmeter, deionized water was injected into heating pipeline for vaporization by adjusting volume in a micro-injection pump to realize addition of vapor and obtain simulated flue gas in such composition as 100 μg/m.sup.3Hg.sup.0, 5% O.sub.2, 10 ppmHCl, 300 ppmNO, 50 ppmNH.sub.3, 500 ppmSO.sub.2 and 10% H.sub.2O, with N.sub.2 as balance gas, air speed of 300000 h.sup.−1 and reaction temperature of 350° C. Mercury concentration was tested with EMP-2 portable mercury analyzer manufactured by NIC and the oxygenation rate of zero-valent mercury was 95%.

(84) The aforesaid example is just a better scheme for the present invention, instead of any form of limitation, and other variants and versions are allowed on the premise of not exceeding the technical solution recorded in the claims.