The benefits of using pressurized steam have been known since ancient times. The use of autoclaves dates back to various cultures over 6000 years ago. The high-pressure steam autoclave was invented by a French scientist in 1879 to sterilize and disinfect medical instruments. Autoclaves are now commonly used in healthcare, laboratories, and commercial food preparation. Today, Estech USA’s Mod-3 System utilizes high-pressure steam and mechanical forces in a rotating vessel to significantly alter the weight of the municipal solid waste while sterilizing it.
During the process...
- 100% of waste is sterilized
- Glass products are broken into small pieces
- Some lastic products shrink into balls while other plastics shrink only little
- Metals are cleaned and crushed
- Labels are stripped off
- Biomass fibers from food, paper stocks, vegetable wastes, and small wood chips are thermo-mechanically pulped
- Food wastes are reduced to various fibers.
- Common household chemicals are hydrolyzed and detoxified
Through this process, the MSW is reduced by 80% by volume. The waste stream contents, now sterile, dry, and virtually odorless, are separated - fiber, metals, plastics, and other misc contents (less that 4% of total). This remainder is sterile and is free of pathogens, litter, and decaying material that attracts vermin and flies. It is ground and used as landfill cover or other architectural fill.
Estech™’s proven and proprietary Fibrecycle® autoclave process is an elegantly simple and robust system that sterilizes, reduces, and sorts municipal waste.
HOW IT WORKS
A Fibrecycle® plant contains:
- An inbound waste-tipping floor
- A main processing area with 2 steam autoclaves and pre- and post-treatment equipment
- Gasifier and a gas turbine electric generator, IGCC
- Water testing and treatment plant
- Hazardous material segregation and isolation equipment
- And a shipping area for recyclables, an office area, maintenance shops, and a central control room.
The Fibrecycle® process begins when waste (with large items removed) is fed from a conveyor into one of the autoclave vessels, and is then evenly distributed in the vessel. The door is closed and sealed, and vessel rotation begins.
While the vessel rotates, steam is introduced and raised up to 7 atmospheres pressure at about 330°F for a processing period of up to 45 minutes. As the cycle proceeds, the vessel contents are dried. The processed, sterilized, and dried materials are then discharged onto an output conveyor. It is pathogen free and is virtually odorless. This allows for easy sorting and handling of the processed material without the health and safety risks associated with raw municipal waste.
The sterilized waste is next fed into a trommel screen where the dry biomass (mostly cellulosic fibers) is separated. Afterwards, valuable products (such as plastics and metals) are extracted for recycling. Iron and aluminum are easily extracted using magnets and eddy current separators. In the European Fibrecycle® model, glass is separated and recycled.
This separated biomass typically represents more than 30% of the municipal solid waste stream weight, and well over 60% of the treated volume – representing an enormous reduction in waste volume. With the metal removal process, municipal waste weight is reduced by more than 80%.
Dry biomass has many beneficial uses. After a detailed examination during the Mod-3 System development period, Estech™ concluded that the best use for biomass was as a solid fuel. Thus, providing renewable energy from a domestic source.
A Standard Mod-3 System includes a pressurized IGCC (Integrated Gasification Combined Cycle). Based on typical US MSW composition, this system generates 10MWe of electricity on continuous basis. This provides 9MWe for sale, 1MWe for plant operations, and a steam source for the autoclave process. Other technologies of various capacities are available for various capacities of the Mod-3 System.