Perhaps 80% of small and medium food manufacturing facilities burn coal or liquid fuel in their boilers and perhaps 80% of these facilities have boilers which have excess pressure on their steam and go to a pressure reducer; or they have stand-by boilers and therefore have that excess capacity.
All of these companies could consider cogeneration or own generation if electricity tariffs are appropriate, says Theo Lotter, new business director of the leading South African industrial boiler supplier and consultancy.
Of course the primary criterion for any business is whether tariffs for both bought electricity and sold electricity allow such a project to be economic. This is a question of where tariffs are now and where they will go to in future.
A comforting factor is that steam generation of electricity is not new technology – in fact it has been around since the industrial revolution. However, it has been improved vastly since then.
Lotter says companies in Africa which could immediately consider such projects are likely to be those which already have waste material to burn in their boilers.
As steam engines are ”external combustion engines”, all varieties of biomass, waste fuels, municipal solid waste, and industrial by-products can be burned in incinerators or waste fuel boilers to make steam. This includes forest products.
This is different from gas turbines or diesel combustion where the working fluid (providing power to a turbine or piston) is directly involved in the combustion.
Steam engines – small, usually fast-running piston engines – scale down in size well, work better with wet steam, and operate on very modest operating speeds.
Lotter says his company can do financial viability studies factoring in the price of electricity to see whether these would be viable. This kind of study could be done every year, following changes in electricity prices. Among factors to be considered besides the price of electricity, are the type of fuel to be used, and the pressure and heat required.
Suppliers of technology related to boiler generation: South Africa: Alstom John Thompson Africa
Tel 0219598400 or 0834486558; email@example.com
Spilling Energie Systeme GmbH
Tel +49/(0)40-789175-0; firstname.lastname@example.org