The high-pressure and high-temperature sampling system (HPHTSS) was designed to extract dust-laden flue gas isokinetically from either an oxidizing or reducing environment. The maximum design temperature of the gas stream is specified as 980°C (1800°F) for the HPHTSS. The maximum working pressure of the gas stream is specified as 150 psig.

The probe is a 3/8-in.-o.d. and 1/8-in.-i.d. 304 SS tube. The probe is used for only one sampling test and then discarded. The key to the sampling system is the use of a vessel designed to withstand high-pressure and temperature conditions to enclose the low-pressure sampling devices.

The process gas is cooled through a set of impingers to remove moisture and organic vapors if present. A set of up to six impingers may be used in this sampling system. These impingers are rated for 200 psig at 120°C (250°F) maximum operating conditions. The impingers are made of 304 SS, with the interior surfaces coated with Teflon. The Teflon-coated surfaces allow the HPHTSS to be used for trace metal sampling.

The dry gas is then throttled to atmospheric pressure and metered through a rotometer and orifice in order to measure total flow. The process gas then reenters the main gas stream for cleanup and disposal.