A. H. Lundberg Associates, Inc. designs the stripper off gas (SOG) system with the utmost concern for both safety and stability of operation. Since the stripper off gas is extremely odorous and toxic, the system is designed so that it does not vent to the atmosphere except under the most extreme upset conditions.

Most condensate stripping systems operate under pressure and therefore do not need an additional motive force for the SOG system. Rupture discs and flame arresters are installed near the reflux condenser. At the point of incineration a rupture disc, mist eliminator, and flame arrester are also installed. Steam make up is added to the SOG line to insure a minimum safe gas velocity during start up, shut down and upset conditions.

The stripper off gas can be burned in all locations including a dedicated incinerator, power or recovery boiler, and lime kiln. When burning in a dedicated incinerator the stripper off gas generally provides more than sufficient fuel value so that continual use of auxiliary fuel is not necessary. Stripper off gas may be liquefied to allow measurement of flow and density as a method to monitor methanol destruction rates. Further, liquefying the SOG permits mixing with the heavy liquor to the recovery boiler and burning as a liquid.

All SOG systems are designed with the appropriate safety interlocks including low flow, high temperature in the line near the point of incineration, rupture disc failure, loss of flame at the point of incineration, and loss of electrical power and instrument air. Under these conditions the system will revert to its fail-safe position and vent to the atmosphere.