Flow rate, of purge gas

The predicting error of flow rate of purge gas OBJpgf... 

The predicting error of hydrogen quench of catalyst bed (STD m /h) The predicting error of flow rate of purge gas (STD m /h)... 

With inert gas as protective gas and an oxygen content inside the containment system = 2% (v/v), the flow rate of protective gas after the purging phase may be reduced to that necessary for maintaining the minimum pressure differential (this may be considered as a shift towards leakage compensation )... 

Pressurization techniques are similar to those used in zones 1 and 2, with the exception that purging shall not be applied. The high flow rate of protective gas during the purging period accompanied by a high velocity of gas may stir up dust layers inside the p-room on components and thus adversely affect the safety of this type of protection. Static pressurization, leakage compensation... 

Purge Gas Flow Rate. The purge gas flow rate can be adjusted up to about 220 ml of argon per minute. Normally the flow rate of the argon... 

A change in the flow rate of the gas used to purge the DSC can have several effects. First, it is possible that it will change the temperature and enthalpy calibration. The magnitude of this variation will vary from one type of DSC design to another as some instruments preheat the purge gas prior to its entering the DSC cell. Second, for experiments where a volatile substance is evolved from the sample when it is heated, the DSC peak shape will be affected by the speed at which the volatile substance is removed. 

Temperature programmed reduction of prepared samples was carried out using a Cahn System 113 thermal balance. The samples were purged in a stream of 85%Ar/15%H2 for 2 hours. Then the temperature was increased to 990°C at a rate of 50°C/hr. The flow rate of the gas mixture was 60 ml/min. 

The basic process as outlined above is very flexible, and modifications and variations can be easily incorporated into it to further improve the overall efficiency and/or to make it more suitable for specific types of feeds. Thus, external fuel, recycle gas, or liquid fuels can be easily introduced into the burner in the case of lean tar sands. By providing for a purge gas stream off the top of the combustion bed, one can adjust the flow rate of fluidizing gas to the pyrolysis bed. If desired, after recovery, gas produced in the pyrolysis bed can be recycled back to that bed and used instead of combustion gases to fluidize it. This is very important for lean tar sands which would otherwise have very low product concentration in the combined exit gas stream, making product recovery difficult. 

Rq is the flow rate of the gas recycle and the molar ratio hydrogen/toluene at the reactor inlet. Equation (7.5) gives the gas recycle if the input of hydrogen and toluene are specified. Further, we may work out the relation that links the feed of toluene Fj-and of hydrogen as function of production, selectivity and purge concentration in hydrogen (see Example 7.3). Finally, for the gas recycle we obtain the relation ... 

Gas recycle. Non-reacted hydrogen and methane is recycled to the reactor by means of a gas compressor. Purge is necessary to prevent methane build-up. The flow rate of the gas recycle is determined by the reaction conversion, as well as by the constraint of a strict ratio hydrogen/hydrocarbon at the reactor inlet. 

A debatable point is the specification of purge. Fixing a purge flow rate or composition is not feasible, because of incompatibility with the overall material balance (see feasible specifications in Chapter 3). On the contrary, setting the purge as split ratio leads always to convergence. Note that in this study we have chosen to keep constant the flow rate of the gas recycle. This is rational, because the compressor is an expensive piece of equipment, which operates preferably at constant flow rate, close to the maximum capacity. 

In start-up it is desirable to purge the headers with fuel gas to remove the air prior to igniting the pilots at the flare tip. The purge time should be at least V/cfh hrs, where V is the total volume of headers (cubic feet), including knockout drum and flare stack, and cfh is the flow rate of fuel gas (cubic feet per hour). 

Figure 3. Recoveries of selected compounds as a function of purge gas flow rate...

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