Dual-function knitted catalytic gauze used for nitric acid manufacture

Abstract

The invention relates to a catalyst used for nitric acid manufacture, in particular to a dual-function knitted catalytic gauze used for nitric acid manufacture, and solves the problems that the existing platinum base alloy catalytic gauze is large in platinum consumption and the filling volume of noble metal platinum, and high in cost. The knitted catalytic gauze comprises a main reaction zone catalytic gauze, a secondary reaction zone catalytic gauze and a postreaction zone catalytic gauze divided according to the direction of ammonia gas along air flow in an ammonia oxidation furnace. The ingredients of the main reaction zone catalytic gauze include 90-95 percent of platinum, 4-8 percent of rhodium and 1-5 percent of palladium; the ingredients of the secondary reaction zone catalytic gauze include 50-73 percent of platinum, 5-7 percent of rhodium and 20-45 percent of palladium; and the ingredients of the postreaction zone catalytic gauze include 9-20 percent of platinum, 1-5 percent of rhodium and 75-90 percent of palladium. By conducting optimal sectionalization of the ammonia oxidation furnace system and the catalytic gauze, the invention fills noble metal of the catalytic gauze according to the proportion and characteristic for different sections completing chemical reaction, thus being in line with the distribution of chemical reaction of ammonia oxidation and simultaneously ensuring the smooth completion of chemical reaction. The platinum gauze of the whole system has the dual functions of catalysis and recovery, the platinum consumption is reduced by 20-30 percent; the total filling volume of noble metal is reduced and the cost of each set of catalytic gauze is reduced by 10-20 percent.

Description

technical field [0001] The invention relates to a catalyst for nitric acid production, in particular to a double-function knitted catalytic net for nitric acid production. Background technique [0002] In the field of nitric acid production, the process route of preparing nitric acid by ammonia oxidation is widely used. Ammonia oxidation is generally completed at a temperature of 800-950°C and a pressure of 0.1MPa to 1.1MPa, and a platinum-based alloy catalyst is used under the above conditions. In addition to the mechanical loss caused by airflow erosion during the use of platinum alloy catalytic nets, most of the loss is volatilized in the form of oxides and lost with the airflow, forming platinum consumption. During the use of platinum alloy mesh, with the passage of time, the consumption of platinum continues to increase, the degree of pollution of the catalyst continues to increase, and the activity of the catalyst gradually decreases, which reduces the production effi...

AI Technical Summary

Problems solved by technology

[0005] The present invention solves the problem that the chemical composition of the multi-layer platinum-based alloy catalytic net used in the preparation of nitric acid in the existing ammonium oxidation furnace is all the same, the utilization rate of the catalytic net in the lower layer of the ammonia oxidation furnace is low, the platinum consumption is large, and the filling amount of precious metal platinum in the entire platinum net is relatively high. To solve the problems of large size and high cost, a double-function knitted catalyst for nitric acid production is provided

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