Number of Burner Jets

For design rates up to 12 MMscfd, the burner lines are usually specified as 6-inch pipe. The common header on the second stage burner would be approximately 18-inch pipe. 

The number of jets is based on gas velocity. For 1-inch standard pipe, the recommended velocity permits a flow rate of 61,200 scfd per jet. Expressed as an equation 

MMscfd means millions of standard cubic feet per day (for a flare system, standard cubic feet is almost always equivalent to actual cubic feet). 

The jets are on a square or rectangular layout with a pitch of 18 to 24 inches. A first estimate of the required pitch can be obtained from the following  

No jets should be placed closer than 12 inches to the inside of the stack. For gases with low heating values, it is usually preferable to decrease the jet pitch to less than 18 inches in order to avoid an increase in the stack inside diameter. It is preferable to keep the pitch above 15 inches. 

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Size, Spacing and Number of Burner Jets - The jet nozzles are 380 mm lengths of 25 mm stainless steel pipe. They discharge vertically from the horizontal burner lines, which run across the bottom of the stack. The jet nozzles are not insulated. 

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