Large Volume Inorganic Chemicals - Ammonia ... - ammk-rks.net

Chapter 33.6 Emerging techniques for nitric acid3.6.1 Combined NO x and N 2 O abatement with addition ofhydrocarbonsDescriptionSee also Section 3.4.7. In contrast to the technique described there, NO x is eliminated byreaction with ammonia in a first step (comparable to an SCR system). In a second step, N 2 O isremoved by catalytic reduction with a hydrocarbon, such as natural gas or propane as shown inFigure 3.13.Hot processgasTail gas fromabsorption:•NO x•N 2OTail gas heaterProcess gasto coolercondenserEmissionto airNH 3300 – 500 ºCExpanderturbineCombinedreactorDe-NO xDe-N 2OHydrocarbonFigure 3.13: Overview of the combined treatment of NO x and N 2 O with hydrocarbonsAchieved environmental benefits• simultaneous abatement of N 2 O and NO x to levels similar to those given in Section 3.4.7 areexpected• expected N 2 O reduction of about 97 %.Cross-media effects• consumption of hydrocarbons and NH 3• no information is available on other potential pollutants (e.g. CO).142 Large Volume Inorganic Chemicals – Ammonia, Acids and Fertilisers