Selective catalytic oxidation of ammonia in synthesis/producer gas streams from ammonia based hydrogen production : A performance evaluation under reducing conditions
(2026) KETM05 20261Chemical Engineering (M.Sc.Eng.)
- Abstract
- Selective catalytic oxidation (SCO) of ammonia is a interesting field of research and is becoming increasingly more popular due to ammonias role as a hydrogen carrier for ammonia based hydrogen production. With the rise of ammonia based hydrogen, focus now lies on finding cheap and efficient ways to remove unreacted ammonia from the final gas stream. This to be done, without burning or destroying the hydrogen by converting the ammonia and some of the hydrogen into nitrogen and water using oxygen and a catalyst.
This thesis aims to investigate and evaluate the performance of five different catalysts, four of which are zeolite based, for SCO of ammonia and to see if they work under reducing conditions when they have been proven to work... (More) - Selective catalytic oxidation (SCO) of ammonia is a interesting field of research and is becoming increasingly more popular due to ammonias role as a hydrogen carrier for ammonia based hydrogen production. With the rise of ammonia based hydrogen, focus now lies on finding cheap and efficient ways to remove unreacted ammonia from the final gas stream. This to be done, without burning or destroying the hydrogen by converting the ammonia and some of the hydrogen into nitrogen and water using oxygen and a catalyst.
This thesis aims to investigate and evaluate the performance of five different catalysts, four of which are zeolite based, for SCO of ammonia and to see if they work under reducing conditions when they have been proven to work under oxidizing conditions. It also aims to find a zeolite based catalyst capable of SCO of ammonia in a reducing environment.
The results shows that the catalysts do not perform well in the hydrogen rich reducing environment and the selectivity for ammonia was at most 40\% and at worst 0\% with it being close to zero to be the more reasonable assumption. The reason for the low selectivity could be attributed to multiple factors but the biggest is most definitely the hydrogen. The hydrogen outcompeted the ammonia for the active sites on the catalysts due to its greater affinity towards metallic copper and silver compared to ammonia, resulting in almost no conversion of ammonia into nitrogen. The hydrogen most likely reacted with the majority of the oxygen before the ammonia could, leading to mostly water forming in the reactor.
The conclusion drawn from the tests was that the catalysts were not selective towards ammonia in the reducing environment. Using catalysts for SCO in oxidizing environments in reducing ones does not work. This was not surprising, however, since so little research on SCO in hydrogen rich environments could be found this was the next best option. Further research is needed on the topic if a zeolite based catalyst for SCO of ammonia that work under reducing conditions is to be found and synthesised (Less) - Popular Abstract (Swedish)
- Vätgas är en av de påtänkta lösningarna när vi rör oss mot en fossilfri värld. Problemet är att vätgas är otroligt knepigt att flytta i stora mängder billigt och effektivt. Istället brukar man ta hjälp av en så kallad vätgasbärare som då ska vara enklare och billigare att transportera utan att man förlorar speciellt mycket vätgas. En sådan bärare som börjar få mer uppmärksamhet är ammoniak. Att omvandla ammoniak till väte är relativt enkelt men kommer inte utan besvär. Reaktionen kan aldrig gå fullt åt vätgas och kväve hållet vilket innebär att det alltid kommer finnas lite ammoniak kvar och den vill man inte släppa ut.
Syftet med detta arbete har varit att ta fram fem selektiva katalysatorer som ska kunna förstöra ammoniaken utan att... (More) - Vätgas är en av de påtänkta lösningarna när vi rör oss mot en fossilfri värld. Problemet är att vätgas är otroligt knepigt att flytta i stora mängder billigt och effektivt. Istället brukar man ta hjälp av en så kallad vätgasbärare som då ska vara enklare och billigare att transportera utan att man förlorar speciellt mycket vätgas. En sådan bärare som börjar få mer uppmärksamhet är ammoniak. Att omvandla ammoniak till väte är relativt enkelt men kommer inte utan besvär. Reaktionen kan aldrig gå fullt åt vätgas och kväve hållet vilket innebär att det alltid kommer finnas lite ammoniak kvar och den vill man inte släppa ut.
Syftet med detta arbete har varit att ta fram fem selektiva katalysatorer som ska kunna förstöra ammoniaken utan att påverkar vätgasen i strömmen speciellt mycket och utvärdera hur de presterade med det ändamålet. Eftersom detta är ett relativt nytt forskningsområde baseras mycket på forskning gjort i andra sammanhang och ska testas att översättas till detta arbetes betingelser.
Resultatet visade tyvärr att ingen av de fem katalysatorer som tillverkades var selektiva nog för ammoniaken och lyckades inte förstöra något. Vätgasen som fanns i strömmen var mer reaktiv till metallerna i katalysatorerna än vad ammoniaken var och konkurrerade ut den om platser på katalysatorerna. Resultatet blev att ingen eller väldigt lite ammoniak förstördes och mest omvandlades vätet som reagerade till vatten.
Slutsatsen är att katalysatorerna som testades inte är selektiva för ammoniak när det finns vätgas i strömmen. Mer tid och forskning behövs för att hitta en katalysator som fungerar under dessa betingelser. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/student-papers/record/9238317
- author
- Graneskog, Carl LU
- supervisor
- organization
- course
- KETM05 20261
- year
- 2026
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Chemical Engineering, Ammonia, Zeolites, Catalysis, Selective Catalytic Oxidation, Hydrogen, Kemiteknik, Ammoniak, Zeoliter, Katalys, Selektiv Katalytisk Oxidation, Väte
- language
- English
- id
- 9238317
- date added to LUP
- 2026-06-22 09:45:44
- date last changed
- 2026-06-22 09:45:44
@misc{9238317,
abstract = {{Selective catalytic oxidation (SCO) of ammonia is a interesting field of research and is becoming increasingly more popular due to ammonias role as a hydrogen carrier for ammonia based hydrogen production. With the rise of ammonia based hydrogen, focus now lies on finding cheap and efficient ways to remove unreacted ammonia from the final gas stream. This to be done, without burning or destroying the hydrogen by converting the ammonia and some of the hydrogen into nitrogen and water using oxygen and a catalyst.
This thesis aims to investigate and evaluate the performance of five different catalysts, four of which are zeolite based, for SCO of ammonia and to see if they work under reducing conditions when they have been proven to work under oxidizing conditions. It also aims to find a zeolite based catalyst capable of SCO of ammonia in a reducing environment.
The results shows that the catalysts do not perform well in the hydrogen rich reducing environment and the selectivity for ammonia was at most 40\% and at worst 0\% with it being close to zero to be the more reasonable assumption. The reason for the low selectivity could be attributed to multiple factors but the biggest is most definitely the hydrogen. The hydrogen outcompeted the ammonia for the active sites on the catalysts due to its greater affinity towards metallic copper and silver compared to ammonia, resulting in almost no conversion of ammonia into nitrogen. The hydrogen most likely reacted with the majority of the oxygen before the ammonia could, leading to mostly water forming in the reactor.
The conclusion drawn from the tests was that the catalysts were not selective towards ammonia in the reducing environment. Using catalysts for SCO in oxidizing environments in reducing ones does not work. This was not surprising, however, since so little research on SCO in hydrogen rich environments could be found this was the next best option. Further research is needed on the topic if a zeolite based catalyst for SCO of ammonia that work under reducing conditions is to be found and synthesised}},
author = {{Graneskog, Carl}},
language = {{eng}},
note = {{Student Paper}},
title = {{Selective catalytic oxidation of ammonia in synthesis/producer gas streams from ammonia based hydrogen production : A performance evaluation under reducing conditions}},
year = {{2026}},
}