Heuristic Engineering Inc.

3040 West 5th Avenue, Vancouver, B.C. V6K 1T9  Canada

Phone: (604) 263-8005  Fax: (604) 263-0786 Email: info@heuristicengineering.com

Converting refuse to energy in the 21st Century

THE EnvirOcycler - BASIC PRINCIPLES

The two-stage EnvirOcycler gasifies wet (wood waste moisture content as high as 65%, wet basis) or dry, shredded, solid waste in a large first stage of gentle updraft gasification. Shredding the waste permits the formation of loose, fluffy fuel piles, a necessary condition for proper gasification. Underfire and overfire air are injected - under tight control - into the first stage to convert the waste into a burnable producer gas.
 
First stage producer gas is immediately burned in a second stage of vigorous cyclonic combustion.  The second stage is located directly above the first stage.  Primary combustion air is injected through a proprietary flame holder at the bottom of the second stage to ignite the producer gas.  High velocity, secondary combustion air is injected tangentially through tuyères (nozzles) in the brick-lined walls to complete combustion of the burning producer gas.

By splitting combustion up into two stages, with two different, tightly controlled, sources of combustion air injected into each stage, it is possible to operate the EnvirOcycler with excess air levels as low as 15%.   This enables the EnvirOcycler to dispose of very wet wastes while maintaining discharge temperatures of at least 1,750°F (950°C) .

Ash Removal

Particulate matter carried up into the EnvirOcycler's second stage is thrown centrifugally out to the second stage walls and falls back down into the first stage.  It is removed from the first stage by the built-in ash removal system.  Shredding the fuel before admission ensures that ash removal is continuous.

In a forest products industry installation in Minnesota the ash is sold as a liming agent to local farmers with full approval from that State's Department of Agriculture. Only about one tenth the normal amount of "lime" is required because of the ash's high pH.

Stack Cleanup

The EPA (Environmental Protection Agency) specifies a particulate limit of 0.08 gr/dscf at 12% CO₂ by volume in §60.52 "Standard for particulate matter" in Subpart E "Standards of Performance of Incinerators", Title 40, Part 60 of the Code of Federal Regulations, Revised as of July 1, 1995.  Regional pollution control agencies can, of course, set tighter standards. Because emissions from the EnvirOcycler are already quite low (less than 0.05 grains on wood waste) the amount of stack cleanup normally required is minimal.