Low load noble metal catalyst for dilute nitric acid reduction, preparation and application

Abstract

The invention provides a low load noble metal catalyst for dilute nitric acid reduction and belongs to the technical field of dilute nitric acid catalysis. Calculated as per the total mass of the catalyst, the catalyst comprises the following ingredients by mass percentage: 0.02-0.25% of active ingredient, 0.5-5% of assistant and the balance of carrier, wherein the active ingredient is one or moreof noble metals Pd, Pt and Rh; the assistant is an alkali metal element K or Na; and the carrier is active carbon. The invention further provides a preparation method of the catalyst, which comprisesthe steps: 1) preparing an assistant saline solution and an active ingredient saline solution in proportion, 2) loading the prepared assistant saline solution onto the active carbon carrier, and drying and roasting to form a standby sample, and 3) loading the prepared active ingredient saline solution onto the standby sample, and drying and roasting to form the catalyst. The loading capacity of noble metals in the catalyst is only 0.02-0.25%; when cost is lowered, the dilute nitric acid reduction can be effectively catalyzed to generate nitrous acid ester; a nitric acid conversion rate reaches above 90%; and nitrous acid ester selectivity reaches 100%.

Description

technical field [0001] The invention belongs to the technical field of dilute nitric acid catalysis, and specifically relates to a dilute nitric acid reduction low-load precious metal catalyst, its preparation and application. Background technique [0002] Ethylene glycol is a bulk chemical product and an important organic chemical raw material. my country has abundant coal resources, and the route of using coal to synthesize gas and oxalate to produce ethylene glycol is developing rapidly in my country. As of March 2018, a total of 17 coal (synthesis gas) to ethylene glycol (CTMEG) projects have been put into operation and successfully tested in China, forming a total ethylene glycol production capacity of 3 million tons per year. It is estimated that in 2022, together with the 17 projects that have been put into production and successfully tested, a total of about 13.5 million tons / year CTMEG production capacity will be formed. In the coal-to-ethylene glycol technical ro...

AI Technical Summary

Problems solved by technology

But the concentration of nitric acid is too low, the reaction is more difficult

In the coal-to-ethylene glycol process, 2wt% dilute nitric acid is generated in the regeneration reaction kettle liquid, and the concentration of nitric acid is low, which limits the conversion of nitric acid

There are bibliographical reports using noble metal catalysts such as 3.5wt% Pd or Pt, which can effectively catalyze the reduction reaction of dilute nitric acid to generate nitrite, but the loading of noble metals is too high, and the catalyst cost is higher; 0.2-2% is used in the report of the patent (CN106565494A) Palladium is the active component, and 0-10% iron or titanium is the auxiliary agent. The prepared catalyst can effectively catalyze the reduction of dilute nitric acid, and the loading capacity of precious metals is reduced.