Equipment purge flow

A corrosive gas, introduced into the thermobalance as a reactant or generated as a product, must be kept away from contact with all metal or reactive parts of the apparatus. Reaction with balance components will (at best) cause error in measurements and (at worst) could ultimately destroy expensive equipment. For experiments involving corrosive compounds, it may be necessary to use balances manufactured from materials that do not react with the particular gases concerned or to include purging flows of inert gas that oppose undesirable contacts for example, a maintained flow across the balance beam is directed toward the sample. 

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. 

The ABB internal pumps plants and ABWR use a seamless wet motor internal pump design. Each pump is equipped with a heat exchanger for cooling and a purge flow that flows to the RPV to prevent crud intrusion. 

Fig. 4. Equipment flow sheet of elemental fluorine production and liquefaction plant, 9 t/d capacity. Step 1 purging residual F2 at rates indicated all but a trace of residual F2 is removed in 15min N2 purge is maintained for 1 h to remove last traces. Step 2 HF removal at rates indicated all but a trace of HF is...

Blowing down Verify flow path before starting the flow. lines for cleaning., Blow (purge) lines to safe location which protects the operator and environment Wear proper personal protective equipment (PPE) Follow proper sampling procedures Use safe blow-down design CCPS G-22 CCPS G-23 CCPS G-29... 

Ignition controls shall include upstream (in flare header prior to knockout drum) dual flow sensing equipment which shall start the automatic flare purge, pilot ignition and the flare ignition cycle. N P Refinery will be responsible for the wiring between the flow sensors and the ignition control panel. 

Filtered air may be used to purge a complete room, or it m be confined to a specific area and incorporate the principle of laminar flow, which permits operations to be carried out in a gentle current of sterile air. The direction of the airflow may be horizontal or vertical, depending upon the type of equipment being nsed, the type of operation and the material being handled. It is important that there is no obstruction between the air supply and the exposed product, since this may resnlt in the deflection of microorganisms or particulate matter fiom a non-sterile surface and canse contamination. Airflow gauges are essential to monitor that the correct flow rate is obtained in laminar flow units and in complete suites to ensure that a positive pressure fiom clean to less clean areas is always maintained. 

Other kinds of electrical equipment may also be used in hazardous locations. One kind is purged and pressurized electrical equipment. This equipment works by using air or nonflammable protective gas flow or pressure to prevent hazardous materials from entering the enclosure NFPA 496 defines three types of purged and pressurized equipment as identified in Table 7-5. 

The outlet of the compressed air supply point is opened and purged for 5 min. Adjust to a flow volume of about 30 1/min. Then the compressed air is passed through an air sampler equipped with a 0.22 pm filter. Sampling time should be about 5 min. This procedure should be performed three times. One filter should later be incubated for anaerobic, the other for aerobic viable count. Viable count should be < 200 CFU/m. ... 

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