Next generation ammonia synthesis: a highly integrated computational modelling and experimental approach

Ammonia synthesis by the Haber Bosch Process is a large scale reaction of major importance since it forms the basis of synthetic fertiliser production, with ca 85% of the ammonia produced being used to feed crops. It has been estimated that the fertiliser produced via the Haber Bosch Process sustains 40% of the current global population. This reaction is becoming more and more important as demand for food increases along with population growth. As operated currently, which involves large scale chemical plants operating at high reaction pressures and temperatures employing hydrogen feedtsocks generated from fossil fuel sources, the Haber Bosch Process is responsible for the consumption of 1-2% of manmade energy and it also results in about 1.6% of the manmade CO2 released to the atmosphere. The aim of this research is to discover and develop new catalysts which can operate in smaller reactors on a local scale such that fertilisers can be prepared close to their point of use. This will cut down on the CO2 footprint of the process since it would be possible to use feedstocks which are non-fossil fuel based and are derived from renewable energy souces such as wind power and also it would negate the requirement for transportation of fertiliser over long distances. The development of such smaller localised ammonia production units, which could be started up and shut down quickly, would require more active catalysts able to work at lower pressures than those currently employed. In this work we are using a combination of computer modelling and experiments to develop such new catalysts. The new localised sustainable ammonia production capabailities which would result from success in this area would also have impact on the growing interest in using ammonia as a fuel to replace the CO2 producing fossil fuels such as petrol and diesel currently employed.

This project integrates materials synthesis and characterisation, catalytic activity testing and computational modelling and prediction to the development of novel ammonia synthesis catalysts applicable to carbon-free ammonia production on a localised scale. As currently practiced, ammonia synthesis is conducted on a large scale with a production rate of ~ 174 million tonnes per annum which is growing at ~ 1.5% per annum. Around 85% of the ammonia produced is applied to the production of synthetic fertilisers which have credited with the sustenance of ca. 40% of the global population. It has been estimated that ammonia production as currently practiced is responsible for around 1-2% of global energy demand when the production of feedstock is taken into account. Much of the hydrogen produced is sourced from fossil based sources neaning that industrial ammonia production accounts for ~ 1.6% of anthropogenic CO2 formation. The increasing availability of renewably derived power, whereby hydrogen can be produced via electrolysis of water, makes sustainable green ammonia synthesis on a localised scale a tantalising prospect. Indeed it has been acknowledged that ammonia may be a suitable store of power in intermittent periods of over supply of renewably derived electricity and in order to accomplish this it will be necessary to develop reactor systems which can started up and shut down quickly. A further driver for localised ammonia synthesis capability lies in the increasing recognition of the application of ammonia as a fuel. In order to achieve these goals it will be neceesary to identify appropriate catalysts capable of activity under milder process conditions. For this,a stepchange advance in ammonia catalyst development is required.
In order to realise any industrial benefit and to achieve maximum impact it is necessary to have direct contact with an industrial company with interests related to this area. Accordingly, Haldor Topsoe A/S are involved as a partner in this project. Under the terms of a non-disclosure agreement, they will provide industrial guidance and also some support in kind. This will include the provision of industrial expertise and attendance at annual progress meetings in addition to receiving progress updates every six months.