Improved membranes and processes for the low energy recovery of ammonia in synthesis plants

Prof. Barry Crittenden, Dr. Semali Perera, Dr. Olivier Camus

University of Bath, Department of Chemical Engineering

This project is targeted at the development of a novel ceramic membrane and process for the most cost-effective recovery of ammonia in ammonia synthesis plants. The manufacturing of ammonia and fertilisers would benefit greatly from a reduction of the energy consumption in the process of ammonia production. Based on preliminary flowsheeting calculations, the use of ceramic membranes for ammonia recovery in the synthesis loop could provide a reduction of about 3% in energy consumption for a 1500 MTPD ammonia plant. The development of this technology would also represent the first commercial opportunity for ceramic gas separation membranes. This development requires the close integration of groups responsible for developing the membranes, providing the data to support the flowsheeting exercise and in carrying out the field evaluation of the products. The two key objectives of the process are the development of cost-effective microporous membranes, which will require a substantial reduction in production cost compared to laboratory devices available today and the development and demonstration of the ammonia separation process in which they will be used. The membrane production cost will need to be reduced to approximately 1000eu/m² if this is to be achieved. This will also need to be combined with a significant advance in our ability to model the membrane performance to allow the use of flowsheet models. The first part of the programme will concentrate on the optimisation of the membrane systems and development of reduced cost production routes. Provided these demonstrate the necessary progress a module will be designed and installed on a commercial ammonia plant to confirm membrane performance under full process conditions.

Keywords: ceramic membranes, gas separation, ammonia recovery