Composite Steam Boiler

The developing countries of the world need to use local energy resources to a much greater extent as a substitute for expensive imported liquid or solid fuels. In many of these countries there is an abundance of renewable energy sources such as wood, seed husks and stalk fibres.

These have proved themselves to be excellent fuel types when burnt in suitably designed furnaces which can supply both heat and power for a wide range of applications.

The Cochrane Composite Boiler
Composite Boiler In response to this energy requirement, Cochrane Engineering, the largest boiler and pressure vessel manufacturers in Zimbabwe, undertook a study of the various established fuel burning and heat transfer systems available. This study revealed that a steam boiler plant incorporating the water tube boiler type furnace, with a shell type convective heat section, would offer great advantages in economy of construction, efficient fuel utilization and high pressure design. These features make it possible to run back-pressure or pass-out type steam turbines, and this permits combined cycle operations for the simultaneous production of electrical power and process steam for heating.

The COMPOSITE Boiler designed and built by COCHRANE ENGINEERING, completely fulfils these requirements.

The COMPOSITE Boiler is offered in a range of sizes as set out below:
STEAM OUTPUT: 5 tonnes/hr to 25 tonnes/hr
PRESSURES: Std. 1 035 kPa. Maximum 3 200 kPa
SUPER HEAT if required Saturation temperature plus 50 C standard: higher super heat temperature can be offered for specific requirements.

FUELS Woodbark, sawdust. Husks: cotton seed, sunflower, wheat. Stalk fibre: bagasse, maize, coconut,
Also : Traditional fuels – coal, lignite, anthracite, oil and gas.


Simple cycle heating with steam, or the production of electrical power through a suitable steam turbine. Combined cycle power and heating, using back pressure pass out steam turbines, with exhaust steam being used for process heating.

Typical Applications include:

Drying of mineral ores
Textile processing
Food cooking and processing
Pharmaceutical manufacture
Crop drying: Maize and Tobacco
Industrial heating: paint shops and oil refining
Abattoirs; cleaning, sterilization and processing of by-products
Milk processing, pasteurizing and sterilizing
Institutions: heating and hot water services
Less time to assemble:

Since furnace and shell are separated extensive dismantling of plant prior to delivery becomes unnecessary. As a result significant time and cost savings can be obtained both in delivery and subsequent assembly.

A successful design:

A prototype of the Composite Boiler was installed for testing at the Forestry Commission’s Erin Forest in North Eastern Zimbabwe. It was highly successful, meeting, and even surpassing all the criteria laid down for it prior to testing, proving that the composite is indeed a real answer to Africa’s growing fuel supply problem.