Microgen boiler. Credit: John Thompson a division of ACTOM

To cater for the growing demand for small, modular medium-pressure power boilers that can accommodate renewable fibrous fuels as well as coal, John Thompson developed the MicroGen boiler range that caters to traditional and new heat power applications.

The article first appeared in ESI Africa Issue 4-2020.
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The introduction of the MicroGen power boiler is particularly suited to renewable fibrous-biomass fuel as well as coal-fired, mini- or micro-grid power islands and industrial co-generation applications. The boiler comes in two designs: the MicroGenV at a nominal 25tph and the MicroGenX at a nominal 45tph at steam pressures between 31 bar(g) and 67 bar(g); and steam temperatures from saturated steam up to 485°C superheated steam, for turbine applications.

These two boiler capacities correspond nominally with net electrical outputs of 5MWe and 10MWe respectively, in the case of single boiler power islands. The compact design incorporates a singledrum configuration with a membranewall furnace construction and flag tube evaporator bank.

“The MicroGenV and MicroGenX boilers are designed to burn biomass, renewable fuels and coal because we are still catering for a number of customers that want to burn coal and biomass for power generation. We supply this power island as a turnkey solution, and have already successfully supplied a 30t/h boiler into the market,” explains Etienne De Villiers, John Thompson Divisional Technical Manager.

As thermal efficiency will be crucial for any energy project, the MicroGen boiler is supplied with a comprehensive heat recovery tower.

The MicroGen boiler is configured to facilitate manufacturing of the pressureparts in large sub-assemblies to facilitate cost-effective transportation and minimise expensive and time-consuming site construction work.

The furnace design incorporates a CAD (continuous ash discharge) stoker, a suitably proportioned furnace and pneumatic fuel spreaders. This configuration can accommodate suspension-firing of small and light biomass size fractions while allowing heavier solid fuel particles to burn on the grate.

As thermal efficiency will be crucial for any energy project, the MicroGen boiler is supplied with a comprehensive heat recovery tower, which includes a tubular air-heater and banks of extended surface economiser. Flue-gas clean-up equipment is supplied to suit the site, fuel and/or customer specific requirements.

The MicroGen is a modular power boiler with the ability to produce electrical power and process steam via turbo-alternator. Its unique design applies Computational Fluid Dynamics (CFD) technology to support optimum combustion and heat transfer while minimising the risk of erosion. The solution’s design is characterised by standard modular units for cost-effective transportation and reduced installation period.

As a leader in the field of boiler technology, John Thompson is committed to product development and the advancement of thermal/combustion technology. Modern boiler design and more efficient combustion methods enable long-term cost-savings and help to maximise uptime while complying with stringent clean-air requirements. ESI

About the company
The company was rebranded in 2009 to ACTOM from Alstom South Africa. Over the years, we have evolved and are proud to have achieved Level 1 B-BBEE contributor status again in 2020. Acquisition of the Savcio Group in 2012 enabled ACTOM to diversify its offering from predominantly manufacturing and distribution to include repair, maintenance and service-related activities. ACTOM is now the largest manufacturer, solutions provider, repairer, maintainer and distributor of electro-mechanical equipment in Africa, offering a winning and balanced combination of manufacturing, service, repairs, maintenance, projects and distribution through its 35 outlets throughout Southern Africa. ACTOM has several fabrication facilities inclusive of three John Thompson facilities. John Thompson is a division of ACTOM (Pty) Ltd.

www.johnthompson.co.za/