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Highlighting on:* Beneficial Use of Nitrous Oxide When Manufactured, and* Its Adverse Impact When Emitted In Traces With the Industrial Gaseous Effects and Other Human Activities
180 oC Highlighting on Beneficial Use of Nitrous Oxide When Manufactured • Introduction • Properties (colourless, critical temperature, critical pressure, boiling point…) • Uses of Nitrous oxide (medicine, semi conductor industry, …) • Nitrous oxide manufacture and market volume NH4NO3 N2O + H2O
Adverse Impact of Involuntarily Emitted Nitrous Oxide There are 2 major sources of N2O emissions: • Improper application of N-fertilizers in agriculture • Oxidation of ammonia for nitric acid manufacture
3. Development of the Nitric Acid Technology • Basic chemistry of nitric acid process has not changed in the last hundred years. • N.B. 4NH3 + 5O2 4NO + 6H2O 2NO + O2 2NO2 3NO2 + H2O 2HNO3 + NO 4NH3 + 4O2 2N2O + 6H2O 4NH3 + 3O2 2N2 + 6H2O 4NH3 + 6NO 5N2 + 6H2O
No-yield , per cent Fig. 1 Change I nitric oxide yield as a function of oxygen-to-ammonia ratio
Development in Nitric Acid Technology • Among various development in nitric acid technology the following milestones are cited: • Development of material of construction: • Construct larger ammonia converters • Construct of big absorption towers for N2O • Development of Catalyst:
Development of abatement systems for NOx in general and N2O in particular • The boom in the measuring instrument made it possible to measure continuously NH3 / NOx in the tail gas (or exhaust goal thus reducing excess ammonia to about) • The development in the catalysis (SCR selective catalytic reduction) made it possible to improve the performance of abatement reaction considerably. To less than 50 pm in tail gas
Development of abatement systems for NOx in general and N2O in particular • The latest development includes a catalyst and process of reducing N2O emissions at the top of the same reactor of NOx emissions The tail gas upstream of tail gas turbine is fed to the reactor first catalyst bed for catalytic thermal decomposition of N2O N2O N2 + ½ O2 -82 KJ Then the tail gas is mixed with ammonia before entering the second catalyst bed where NOx is catalytically reduced to N2 & water vapor 4NO + 4HH3 + O2 4N2 + 6H2O -1628 KJ 3NO2 + 4NH3 7/2 N2 + 6 H2O -1367 KJ