Chlorine valve leaks

Parts of chlorine cylinder, tools and procedures to stop leaks, valve leaks, fusible plug thread and metal leaks, side wall leaks, and installationn of valve hoods. 

The chlorine header should be maintained at positive pressure to permit detection and correction of any chlorine piping leaks. The hydrc en header is also maintained at a positive pressure to avoid pulling air into the hydrogen, creating a potentially explosive mixture. The brine header pressure should be maintained to give the desired caustic concentration in the cell liquor. Normal practice is to adjust individual brine feed valves so that each cell receives the correct brine flow rate. 

After changing a chlorine cylinder, two workers opened the valves to make sure there were no leaks on the connecting pipework. They did not expect to find any, so they did not wear air masks. Unfortunately there were some small leaks, and they were affected by the chlorine. 

C for mixtures containing 8-18% of hydrogen [8], A faulty non-return valve allowed hydrogen to leak into a fibreglass-reinforced pipeline containing chlorine, and spontaneous ignition and explosion occurred [9],... 

The evening shift loaders first task was to return the repaired chlorine line to service. The loader quickly pressured the section of piping with 100 psig (690 kPa gage) compressed air and determined the repairs were leak-free. He next opened a valve connecting the 2-inch (5 cm) pipeline to 160 psig (1100 kPa gage) compressed chlorine gas. 

The stainless valves were improper, but if they leaked slightly during normal operation dry chlorine would enter the scrubber and harmlessly be neutralized. FFowever, during this startup with the piping under a vacuum, moisture from a slight leak managed to combine with the dry chlorine and create an aggressive corrosive fluid. 

Chlorine tank car manway, four angle valves, safety relief valve, packing gland leaks, installing valve hoods and outlet valve nuts, yoke assemblies, and checking tank car pressure. 

In ease of aceidental release of chlorine gas, sueh as from a leaking cylinder or associated apparatus, evacuate the area and eliminate the source of the leak if this can be done safely. Full-face suppUed-air respiratory protection and protective clothing may be required to deal with a ehlorine release. Cylinders with slow leaks should be carefully removed to a fume hood or remote outdoor locations. Chlorine leaks may he detected by passing a rag dampened with aqueous ammonia over the suspected valve or fitting. White fumes indicate escaping chlorine gas. 

Excess flow valves are standard additions to pump discharge lines. These prevent too rapid discharge of chlorine if the line leaks or even breaks. The rising-ball design is a standard, illustrated by Chlorine Institute Drawing No. 101. 

Leaks Call for emergency assistance. If leak is around valve stems, try to tighten the packing nut or packing gland. If leak does not stop, close container valve. If possible, reduce pressure in the container by removing the chlorine as a gas (not liquid). Move container to an isolated area. 

Gaseous Products Gases like Oxygen, Nitrogen are filled up under high pressure. All the fittings should be tested to be leak proof at up to 150-200 kg/cm and approved by statutory authorities. Gas cyUnders should be procured from approved manufacturers only and should have serial no, test pressure, date of discontinuation from service marked. Separate record should be kept for each of the gas cylinder procured. The valves should be tested prior to purchase. Only standard colour code should be followed, e g. yellow for chlorine, black for oxygen etc. by the manufacturer. 

Do not spray water on a chlorine leak. To do so makes the leak worse because of the corrosive action of wet chlorine. When a leak occurs in equipment in which chlorine is being used, immediately close the chlorine container valve. 

If a chlorine container is leaking in such a position that chlorine is escaping as a liquid, the container should be turned if possible so that chlorine gas escapes instead. The quantity of chlorine escaping from a gas leak is about one-fifteenth the amount that escapes from a liquid leak through the same size hole. Leaks at valve stems are often stopped by tightening the valve packing nuts or closing the valve. 

Leaks in the vicinity of the cylinder and ton container valve stems can usually be stopped by tightening the packing nut. If this does not stop the leak, the valve should be closed and the chlorine in the outlet piping evacuated. If the valve cannot be shut leak-tight, the outlet cap with gasket should be installed. In the event the valve continues to leak, the applicable emergency kit recommended by the Chlorine Institute should be used to seal the leak and the cylinder/container moved to a safe area. See the section Emergency Kits. ... 

Leaks. If ammonia vapor is directed at a leak, a white cloud will form indicating the source of the leak. A plastic squeeze bottle containing aqua ammonia can be used. If such a wash bottle is used, the dip tube should be cut off so that squeezing the bottle directs vapor, not liquid, out of the nozzle. Contact of aqua ammonia with brass or copper is to be avoided. Commercial 26° Baume aqua ammonia should be used. If a leak co-curs in equipment or piping, the chlorine supply should be shut off, the pressure relieved, and necessary repairs made. Gas leaks around a valve stem may usually be contained by tightening the packing nut. 

Use methyl chloride in a well-ventilated area only, preferably a hood with forced ventilation. The cylinder should never be directly connected to a container of liquid, since reverse flow can occur, causing a reaction within the cylinder. To prevent reverse flow, a trap, check valve, or vacuum break should be inserted into the line. Cylinders of methyl chloride should be stored and used only in well-ventilated areas away from heat and all sources of ignition such as flames and sparks in order to avoid fire and explosion hazards. Flames should never be used to detect methyl chloride leaks use a soapy water solution. Do not use methyl chloride around sparking motors or other non-explosion-proof equipment. Reserve stocks of methyl chloride cylinders should not be stored with cylinders containing oxygen, chlorine, or other highly oxidizing or flammable materials. [4]... 

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