Lead by Dr Simon Beaumont and Dr Andrew Smallbone of the Chemistry and Engineering Departments respectively, Durham University is collaborating with Johnson Matthey, NFU (National Farmers’ Union) Energy and the University of Nottingham to reduce greenhouse gas emissions in the agriculture industry.
Methane and nitrous oxides are the main gases released by the farming sector, which is responsible for 10% of annual UK greenhouse gas emissions. Up to half of this is due to the methane released when cows and sheep digest the cellulose that makes up a large proportion of their diets (so called “moo-thane”).
The £250,000 project aims to apply existing methane catalyst technology (COMET™ technology from Johnson Matthey) developed for use in coal mines to the barns in which a significant proportion of this methane is released by cows and other animals.
The COMET™ technology refers to a ‘bimetallic catalyst based on platinum and palladium, for the oxidation of methane to form carbon dioxide and water.
This conversion is worthwhile as methane has been shown to be more effective at trapping heat over 100 years than carbon dioxide – the Environmental Protection Agency in the United States calculates that methane is 25 times more potent as a greenhouse gas than carbon dioxide.
The presence of the COMET™ catalyst reduces the temperature required for this reaction to below the auto-ignition temperature of methane. It also improves the economic and environmental viability of the reaction, as well as helping to make it effective at such low concentrations of methane.
COMET™ was designed in order to reduce amounts of methane present in mines (where its risk of combustion when mixed with air created a hazard) in which concentration in the air is typically in the order of around 1% – making any chemistry particularly difficult. It is estimated that in barns methane concentrations are even lower. This project aims to prove whether the catalyst can work efficiently at lower concentrations than it was designed for initially or can be adapted to do so.
As well as the concentration of methane, other factors under consideration for this application of the technology include seasonal changes, barn architecture and other compounds within the air in barns. For example, water is an inhibitor of the reaction described above so humidity ranges must be considered.
The agriculture industry has a net zero emissions goal by 2050 set by the UK government. The NFU has gone one step further and aims for zero greenhouse gas emissions across England and Wales by 2040. In order for this goal to be reached, many changes will have to be made including wider implementation of mixed rotation and introduction of more nitrogen fixing plants such as clover to avoid over-use of fertilisers. If the COMET™ technology turns out to be applicable, it will be a great asset to the farming industry reducing their emissions and potentially reaching this milestone.
Image: Victoria Cheng