Staged hydrocarbon combustion system

A process for the combustion of hydrocarbon vapors, comprising:

• passing the vapors through a first vapor directing assembly to a flare stack for disposal of the vapors at one end of the flare stack, the passage of the vapors through the first vapor directing assembly continuing until the flow rate of the vapors reaches a first predetermined value;
• passing the vapors at and above the first predetermined flow rate through a second vapor directing assembly to the flare stack, the passage of the vapors at and above the first predetermined flow rate through the second vapor directing assembly continuing until the flow rate of the vapors reaches a second predetermined value;
• and
• simultaneously passing the vapors having a flow rate at least equal to the second predetermined value through the first and second vapor directing assemblies for disposal of such vapors in the flare stack.

A hydrocarbon vapor combustion apparatus for disposal of hydrocarbon vapors comprising:

• an elongated stack having a first end, a medial portion, a second end and a centrally disposed passageway extending therethrough, the medial portion having at least a first port and a second port openly communicating with the centrally disposed passageway;
• first vapor directing means extending through a portion of the centrally disposed passageway of the stack via the first port for discharging vapors at low flow rates into a combustion zone at the second end of the stack;
• first valve means disposed within the first vapor directing means for directing the flow of vapor through the first vapor directing means;
• fluid seal means communicating with the first vapor directing means for preventing flashback from the stack upon burning of the vapors at the second end of the stack, the vapors being introduced into the fluid seal means at a position below a fluid level and being withdrawn therefrom at a position above the fluid level;
• second vapor directing means extending through a portion of the centrally disposed passageway of the stack via the second port for establishing fluid communication between the first and second vapor directing means and for discharging vapors at intermediate flow rates into the combusiton zone at the second end ofthe stack;
• second valve means disposed within the second vapor directing means for directing the flow of vapors through the second vapor directing means;
• and
• flow rate measuring means for measuring the flow rate of the vapors from the fluid seal means, the flow rate measuring means operably connected to the first and second valve means such that the vapors are selectively discharged at the second end of the stack into the combustion zone via the first and second vapor directing means, the flow rate measuring means operably directing the first valve means in an open mode and the second valve means in a closed mode at low flow rates less than a first determined flow rate value, the flow rate measuring means operably directing the first valve means in a closed mode and the second valve means in an open mode at intermediate flow rates equal to and greater than the first predetermined flow rate and less than a second predetermined flow rate, and the flow rate measuring means operably directing both the first valve means and the second valve means in open modes at high flow rates equal to and greater than the second predetermined flow rate.