Purge air

As initially discussed in Section 3, carbon canisters are used in the automotive emission control system to temporarily store hydrocarbon vapors. The vapors are later purged into the air charge stream of the air induction system, thus regenerating the carbon canister. Carbon canister design is dependent on the characteristics of the vapors sent to the canister and the amount of purge air available. In the following section, factors that affect the performance of the evaporative emission control system will be discussed. 

After purging air out of the cell and the tubes with nitrogen, electrolyte saturated with nitrogen was introduced to the cell. 

TPD-NH3 curves were obtained in a temperature range of 120 to 600°C, at a rate of 15°C/min. The adsorption of ammonia onto the sample was carried out at 25°C. Subsequently, the removal of ammonia was performed at 500 or 550°C for 1 h by purging air or pure nitrogen. Blank runs were carried out under the same conditions but with no NH3 adsorbed. The TPD-NH3 curves were obtained after subtraction of the blank run. 

Pellet degassing, however, still presents a problem. The volume of purge air required to degas the pellets makes recovery of ethylene from the purge stream using conventional methods uneconomical. 

As shown by Leonard (1988), purge air can be used to protect motor (or rotor) bearings from corrosive fumes in the contactor stage. This approach can work well as... 

The system consists of a water cooled ring adapter with purge air supply (Figure 29) and of a control and evaluation unit. The laser beam with an excitation wavelength of 1064 nm is focused in the measurement volume by a light fiber and the enhanced thermal radiation is captured by an appropriate detector head perpendicularly. It can be applied directly in the raw exhaust without dilution up to exhaust gas peak temperatures of 700°C. Its sensitivity (3 (ig/m3) and variability for realtime (20 Hz) soot characterizing in different applications is shown. 

Optical Access kept free by means of purge air supply... 

Purge air from pump head or check valves. Change pump seals if necessary. Be sure mobile phase is degassed. 

Relief devices Emergencies Process isolation Instruments Adequacy, vent size, discharge, drain and support Dump, drown, inhibit and dilute Block valves, fire-valves and purging Air quality, time lag, reset wind-up and materials of construction... 

Vacuum Drying Books. (A) Frozen (or wet) books are placed in a chamber and heated by warm air. Vacuum is applied to remove water vapor as the ice thaws (5, 7). This is sometimes called the purged air system. (B) Frozen (or wet) books are placed in an unheated chamber. Moist air is evacuated and replaced with dry heated air (0% r.h.). When the replacement air becomes saturated with moisture, it is evacuated and the process repeated until the books are dry (4, 5). (C) Thawing books are put in a chamber. Vacuum is applied and then controlled at a pressure of about 5 torr. Heat is then applied to books through shelves to replace latent heat of vaporization. As moisture is released from books in vapor form (outgassing), it is collected by pumps and reverted to ice on cooled condensers in the chamber. After most of the water leaves the books, the book temperature is increased gradually from 32 °F to 80°-85°F the chamber is opened after 48 hr, the books are removed from the shelves, and the condensers are defrosted (4,5,10). 

The feed gases enter the adsorbers at 400 psia and 80°F. The product gases leave the adsorbers at almost 400 psia and a temperature of 140°F. Regeneration includes 30 ft3 (SC) of flue gas per pound of carbon and 80 standard cubic feet of purging air per pound of carbon. The flue gas is at 600°F (its maximum temperature) and 5 psig, and the air is at 90°F and 5 psig. The air may reach a maximum temperature of 600°F at the start of the purging. 

---