Superior Solid Fuel Conversion - VIGC
The AESI biomass fueled thermal systems fully apply the process of first converting the solid fuels to gaseous phase followed by combustion of that gas thereby delivering heat to a fire tube boiler heat exchanger (Vertically Integrated Gasification and Combustion – VIGC). The demonstrated reasons of this approach as superior to others in current use are visibly apparent and best understood in a comparative setting.
Solid fuel boiler plants generally appear in three principle arrangements
- Integral Grate where the fuel is burned inside the boiler firing chamber,
- Dedicated Furnace where the fuel is burned in a separate unit, and resultant heat is ducted to the boiler
- Gasifier Combustor which updates from Dedicated Furnace to Gasification.
VIGC is a further advancement
- In the VIGC, burning solid material is replaced with Gasification technology.
- VIGC further extends the moisture and low quality fuel range, up to an acceptance of 60% by mass of water.
- Because the fuel is first converted to gaseous state, combustion efficiency is improved considerably across the range of boiler operation and the solid fuel calorific content is completely removed.
- This absolute fuel energy extraction in turn, lowers fuel consumption and units operate well in turndown ratio of 5:1 or better.
- When even greater turndown is required, the VIGC shuts down into 'Slumber' mode between periods of operation, reverting to full output when demand renews.
- VIGC emissions control is self fostered. Firstly because of the complete consumption of carbon materials during the gasification process, and followed by complete and high temperature combustion of the produced gas.
- Further to emissions, the VIGC is the result of decades of study and improvements, using the physical advantages created by proper geometry of internal, dry combustion chambers, reflective orientation of refractory, and the reduced fuel gas velocity which delivers in process residence times of over 4 seconds.
- In combination the above results in reduced boiler tube cleaning and maintenance and provides a clear emission flow, even prior to a baghouse.
- The VIGC also delivers improved safety of the operation, heating response is faster and the units are made for positive dump of surplus heat in alarm conditions.