High energy arc ignition of pulverized coal
AssigneeCombustion Engineering, Inc.
InventorsMartin E. Smirlock, Donald A. Smith
Life of this patent
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Abstract
An electrical discharge is controlled in such a manner as to permit its use to reliably ignite a fuel stream consisting of pulverized coal entrained in air. The ignition technique of the present invention creates expanding and contracting plasma pockets at a rate which is high compared to the velocity of the fuel stream and permits the ignition of the fuel stream in a cold furnace and/or without supplemental combustion of liquid or gaseous hydrocarbon fuels.
Claims10
A method for igniting a fuel stream comprising pulverized coal in the absence of any sources of ignition energy other than an electric arc ignitor disposed in the stream, said method comprising the steps of:
- establishing a fuel stream having a transport air-to-coal weight ratio of less than unity and having a velocity not exceeding 150 feet per second;
- directing the fuel stream to an ignition zone, an electric arc ignitor projecting into the ignition zone;
- and
- creating an intermittent electric arc in the fuel stream at the ignitor tip, said arc being established at a frequency in the range of 8 to 12 times per second, each arc lasting for between 100 and 200 microseconds and resulting in the dissipation of between 6 and 12 Joules of energy at the ignitor tip.
Dependencies are inferred from the claim text.