Purging regulators

Flush (purge) regulators used for corrosive gases with dry air or dry nitrogen into a trap or hood. The regulators used for corrosive gases should be serviced at 3- to 6-month intervals. 

Figure 2.48 Injector back pressure regulation. 1. Carrier gas inlet filter, 2. mass flow regulator, 3. electronic pressure sensor, 4. septum purge regulator, 5. solenoid valve, 6. electronic pressure control valve and 7. injector with column installed.

If ah systems are go, turn on the seal gas. Open the expander and eompressor ease drains to purge systems. Close drains and eheek seal gas pressure. Seal gas temperature must be 70-80°F downstream of the regulator. 

Personnel and equipment need to be decontaminated in the CRZ. However, the CRZ might be a small area immediately adjacent to the remediation area, which workers are aware of, and is also marked appropriately. Although the CRZ is less formal and likely does not have many decontamination stations, efforts should be made to make sure that personnel and equipment are appropriately cleaned. Many times, due to the logistics of a smaller job, disposal of wastes becomes difficult. If purge water is drummed and left on the site, it is imperative that it is identified, labeled properly, recorded in the site log, and disposed of in the proper manner (in accordance with applicable, local, state, federal, or other regulations). 

Figure 14.10 Schematic diagram of the aromatics analyser system BP, back-pressure regulator CF, flow controller CP, pressure controller Inj, splitless injector with septum purge V, tliree-way valve column I, polar capillary column column 2, non-polar capillary column R, restrictor FID I, and FID2, flame-ionization detectors.

After testing for soundness it will be necessary to safely introduce gas into the pipework displacing the air or inert gas that is in it. Similarly, if pipework is decommissioned for any reason fuel gas must be displaced by air or inert gas. This is a requirement of the Gas Safety (Installation and Use) Regulations, Regulation 21. Guidance on recommended procedures is given in the British Gas publication Purging Procedures for Non-Domestic Gas Installations (IM/2). 

After soundness testing and purging, a competent person must commission the item of plant. It is a requirement of the Gas Safety (Installation and Use) Regulations, Regulation 33, that an appliance is fully commissioned at the time that gas is made available to it or that it is isolated in such a manner that it cannot be used. 

Gas pressure must be properly regulated, all lines purged before use, and ignitors proven to work before initial startup. Also, all gas burning equipment must be regularly inspected for leaks to avoid risks of an explosion. 

Control the carriage of dangerous substances in all road tankers and in tank containers with a capacity of 3 m or more. They apply to all substances which exhibit any of the dangerous properties detailed in Schedule 1 to the regulations, from the commencement of loading until the tank has been emptied and cleaned or purged, so that any residual substance or its vapour is not sufficient to create a risk to health and safety. 

The oxygen from the dual gas regulator module flows directly through two ports into a closed-end manifold in the fuel cell stack to provide optimum oxygen distribution in the cells. All the oxygen that flows into the stack is consumed, except during purge operations. 

We mentioned in Chapter 2 (Section 2.6.1) that a purge-and-trap procedure sometimes precedes an analysis by gas chromatography. An example of this procedure is found in the City of Lincoln, Nebraska, Water Treatment Plant Laboratory. Water treatment includes chlorination. When water is chlorinated, chlorine reacts with organic matter to form trihalomethanes (THMs), such as chloroform, bromoform, bromodichloromethane, and chlorod-ibromomethane. THMs in water are regulated by the Safe Drinking Water Act, and so the laboratory must analyze the treated water to determine their concentration. 

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