GlassPack®

Glass
Aggregate
Technology

Glass Furnace
Technology

   Sediment
   Vitrification

   Glass Furnace
   Technology
   Feasibility Study

   MGP
   Waste Testing

   Q&A

   Vitrification vs.
   Incineration

Lightweight Aggregate

Testing
Services

Combined Heat
and Power

Home

Site Map

Technologies > Glass Furnace Technology > Sediment Vitrification

Sediment Vitrification
Glass Furnace Technology, or vitrification, is a relatively simple process that has been used for centuries to melt minerals into glass. Glass melting in its basic form has not changed significantly since the Middle Ages, the only difference being contaminated river sediment is substituted for sand and limestone, the typical raw materials in glassmaking. The end product of processing river sediment is a granular, black glass aggregate that has many uses in the construction industry.

Dryer
A thermal dryer is used to remove water from the sediment. The primary purpose of pre-drying the sediment is to improve the energy efficiency of the vitrification process. An additional benefit is that the size of the sediment melter can be minimized by reducing the amount of water in the feedstock. A heat exchanger transfers energy from the melter's hot exhaust gas into the thermal dryer, where it is used to evaporate the water.

Not shown on this diagram, but nonetheless integral to the system, is the sophisticated closed-loop dryer exhaust treatment system. The water vapor that is removed from the sediment is not vented to the atmosphere; instead, it is directed to a condenser system that converts the vapor back to water. The water is then pumped back to the dredging system's water treatment facility. Since this is the original source of the water contained in the sediment, it does not represent a new source of contaminants.

Feeder
Dried river sediment is fed into a mechanical feeder on one end of the melter. The feeder conveys the sediment continuously into the main section of the melter.

Melter
The melter is built of refractory brick that has been specially treated to resist chemical and physical abrasion, has a high melting point, and provides a high degree of insulation. A series of oxy-fuel burners directed into the side of the melter combine natural gas and oxygen, raising the internal temperature of the melter to 2,900 degrees Fahrenheit. At these temperatures, organic contaminants (such as PCBs) are destroyed, and the sediment melts and flows out of the processing system as molten glass.

Quench Tank
Molten sediment remains in the melter for several hours before it flows from a tap into the water-quenching tank. The cool water is used to harden the molten glass into glass aggregate. Quenching with water improves the hardness of the glass, yielding it inert to the environment. The hardened glass is removed from the quench tank by a screw conveyor as glass aggregate.

Heat Recovery
A heat exchanger extracts energy from the melter's hot exhaust gas. The heat energy is transferred to the dryer for use in removing water from the incoming sediment. Heat transfer is performed by pumping thermal fluid in a closed loop between the dryer and the heat exchanger. By removing energy from the exhaust gas, the heat recovery system also cools the exhaust gas prior to the air quality control system.

Air Quality Control and Carbon Filter
The air quality control system includes several technologies that are proven to be highly efficient at the cleanup of exhaust gasses. These systems include a wet scrubber, a fabric filter and a carbon filter. The wet scrubber eliminates SO2 and HCl, the fabric filter removes particulate (dust), and the carbon filter captures mercury. Together, these systems represent the state-of-the-art in air cleanup technologies.

<back 1 2 3 4 5 6 next>