The pulp mill environment is tough; its dirty, its humid, it poses safety risks to personnel, facility, & equipment. There are serious concerns about fire and explosions but also sample delivery and maintennce. You need a reliable monitoring system.
Most monitoring systems are only able to measure the percent of flammability of a specific gas or narrow family of gases. In pulping applications, however, it is necessary to measure the overall concentration of all flammable gases and vapors entering the incinerator.