Carbamide Power Systems - Urea Fuel Cells for Low Cost Energy

Lead Research Organisation: Heriot-Watt University
Department Name: Sch of Engineering and Physical Science

Abstract

Building on our previous funding (EP/F028083/1) this project aims to demonstrate a prototype fuel cell technology using low cost catalysts, an alkaline conducting polymer membrane and a non-toxic easily distibuted renewable fuel source. Fuel cells are a high growth multi billion pound market and find application within vehicles, mobile and stationary power generation and off-grid applications. Fuel cells operate by reacting a fuel such as hydrogen, ammonia gas or an alcohol such as methanol with an oxidant material (usually atmospheric oxygen from the air) to give water, carbon dioxide, nitrogen and electrical power. The drawbacks of such fuels are that hydrogen gas requires storage at low temperatures or high pressures making it difficult to distribute in bulk; ammonia and methanol are toxic to humans and animals. Urea offers a potential alternative fuel source; it is a low cost, mass manufactured, easily transported, non-toxic solid used as cheap fertiliser, is a major component of human and animal urine and is already sold as a pollution reducing additive for diesel vehicles, providing a readily accessible distribution network. Fuel cells typically comprise several components; a fuelling system, catalyst layers and a conductive membrane material sandwiched together forming a membrane electrode assembly or MEA. Multiple MEA are then assembled together forming a fuel cell stack that can be integrated into a vehicle etc. Within this project the funding will be used to optimise a fuel cell system described in our GB patent application (filed May 2009) focusing on developing novel economic catalyst materials and polymeric electrolyte membranes suited to non-toxic fuel for application in MEAs operating below 100oC. Existing polymer electrolyte membranes (PEM) such as the fluoro-polymer Nafion are proton conductors and are optimised to use hydrogen gas or methanol as the fuel source. It was shown in previous research that acidic proton exchange polymers do not work with basic fuels as they are chemically incompatible. Within conventional PEMFCs the catalyst materials are often of precious metals, such as platinum or rhodium more common in jewellery than power systems. These materials can be very expensive (>30000/ kg) and although used in small amounts in fuel cells they are a major contributor to overall cost, creating a barrier to mass uptake. Platinum catalysts can also be poisoned (de-activated) by fuel contaminants such as carbon monoxide causing cell failure and although alternate, non-platinum metal catalysts are in development they are some time from commercial application. In addition to developing a prototype fuel cell that overcomes the above problems our initial evaluation of our market competitors and IP position indicates opportunities to develop the technology in a number of unique market sectors within renewable energy, mobile & stationary power and water treatment both within the UK and overseas. During the funding period a comprehensive freedom to operate study will be undertaken and business plan for technology commercialisation developed identifying areas of commercial exploitation enabling the work to be carried forward into a commercial activity on completion. The follow on funding will allow the retention and development of key research personnel with specialised skills in electrochemistry who will gain additional experience of commercially driven product development.

Planned Impact

Major beneficiaries of the project will be companies active in the renewable energy, portable device, water treatment and electricity generation sectors where urea can be used directly as a source of fuel providing power for mobile devices, vehicles etc. Urea solutions such as AdBlue or Greenox are available globally as NOx reducing additives for diesel vehicles fitted with SCR catalysts but at this time there is no use for them outside of this application and a niche market opportunity exists to use urea as a power source. Within the UK technology licensing to fuel cell developers such as Johnson-Matthey, AFC Energy or ITM Power etc would allow them to raise finance to invest in capital equipment and manufacturing processes to develop new products, enter new markets to securing existing or create new jobs. Urea is a component of waste water (e.g. municipal sewage works) and the technology can be used to purify the water producing electricity as a by-product reducing the biological impact of such waste on the environment. Urea is a non-toxic low-cost industrial product which is widely used as fertiliser. Urea can be synthesised from ammonia produced from natural gas or coal. Global urea production is about 140 million tons per year. Bulk urea retails for ~US$ 250 per ton offering a low cost energy vector and is readily available as AdBlue, a 32.5% urea solution developed by Europe's AdBlue urea- selective catalytic reduction (SCR) project and is available worldwide to remove NOx generated by diesel powered vehicles. Despite the high availability of urea, there is currently no technology able to generate electricity from urea or AdBlue. A large amount of human or animal urine, containing about 2-2.5wt% urea, is produced everyday. There is a significant level of urea in municipal waste water but the available denitrification technologies are expensive and inefficient. Recently it has been reported that hydrogen can be generated from urine or urea-rich waste water through electrolysis. However, to generate electricity directly from urine or urea-rich waste water would be a better choice. Urine has been regarded as a 'liquid gold' (Chemistry World, August, 2009, p. 25) therefore urea/urine fuel cells will be an ideal way to 'extract' energy from urine or urea-rich waste water in the future. In short term, urea fuel cells can be used for off-grid power generation, for example, to provide power for telecommunication towers. It can be used for portable and transport applications if the power density is high enough through further development. Continuing developments in fuel cell technology are consistent with the demands of the recent UK White Paper on a low carbon future for the UK and are likely to result in appreciable export opportunities for UK industry. The industrial partners will all benefit from the proposed research, but so will other UK fuel cell developers as well as component suppliers control providers and those potentially involved in the application of fuel cell based systems, such as BOC, BP, Air Products, and others. Benefits will arise from technological enhancements in the fuel cell sector, allowing UK players to continue to compete on a world-stage and by provision of trained staff to the UK fuel cell industry.

Publications

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Description The key finding of this project is that, the low power density of urea/urine fuel cells is mainly limited by the sluggish anode activity thus to develop efficient anode catalysts will be the key to the application of urea/urine fuel cells.
Exploitation Route The relevant experimental results have been published in international journals which are shared with researchers in the fuel cell community.
Sectors Energy

Environment

 
Description We were invited to write a paper on the topic of Urea/urine fuel cells. This paper was published in magazine, Science Pictorial, June 2011. This will make the public to have better understanding of this technology.
First Year Of Impact 2011
Sector Education,Energy,Environment
Impact Types Cultural

Societal