How is oxygen supplied?
Two options are available. One is cryogenic oxygen storage. In many cases, an oxygen supply company will provide a tank and deliver liquid oxygen as needed to maintain the inventory to supply the system. On-site oxygen generation is another option that may be economical for higher use and continuous application. This system consists of a skid-mounted production plant that contains compressors, vacuum pumps and a molecular sieve to separate oxygen from the nitrogen in ambient air.
Is oxygen dangerous?
Oxygen is a common commodity found in hospitals, wastewater treatment facilities and an array of other facilities, including glass furnace plants. The codes for designing, installing, and maintaining oxygen supply systems are well developed and problems are extremely rare.
Is oxygen expensive?
The costs of producing oxygen have fallen in recent years because of drastic improvements in air separation processes. On a per weight basis, oxygen is one-seventh the cost of natural gas. In addition, using oxygen provides an order of magnitude reduction in exhaust gas. The significant improvement in emissions reduces off-gas treatment costs and ultimately reduces the capital costs of the facility.
How is the process started and stopped?
A small quantity of natural gas is used during startup to bring the unit up to temperature before introducing the feedstock. If a problem necessitates interruption or immediate shutdown, this can be achieved without damage to any equipment or hardware. In a normal shutdown, natural gas would be increased to maintain temperature in the combustor as the solid feedstock is reduced.
What about air permitting?
In many situations, a GlassPack® system should be within the guidelines for a minor source or a general exemption. Air permitting criteria and sludge characteristics vary regionally. Process vent flows are low enough that the size, complexity and cost of any control technologies would be substantially reduced.