Examples, condenser leak

In cases where water should not come into contact with the vapours being eon-densed, the shell side may be operated at negative pressure, that is, under siphoa In case of a tube leak, the condensing vapour will get mixed with water and get earned away from the condenser due to the siphon. An on-line pH meter can indicate the leak if the vapour is acidic. Some other detector, for example, conductivity meters, can also be used. For example, Condenser for Liquid SO ... 

When a leak occurs between the process and one of the utility systems, it is often difficult to track down the source of the leak. For example, it is quite common to place a hydrocarbon detector in the plume from a cooling tower. Then, if one of the process coolers or condensers leaks, the detector will detect the presence of hydrocarbons. The difficulty lies in knowing which of the equipment items is leaking. 

Another item to keep in mind is that if there is any leakage in a system such as this, the leakage will be preferential. For example, a vapor leak in the condenser would leak proportionally more propane than butane. This would change the performance of the cycle considerably. 

The inspection of equipment in-service and in the process of failure presents a very dangerous problem to the inspector. The corrosion inspector must take the utmost care in such a situation in order to avoid both injuries and contamination of the environment. It is no exaggeration to state that this problem presents a significant challenge to the inspector. An example of this type of inspection is a leaking condensate-storage tank under pressure. In this situation it is important that the operation is shut down before beginning the safety inspection. 

Most condensers used in steam power plants operate at pressures well below the atmospheric pressure (usually under 0.1 atm) to maximize cycle thermal efficiency, and operation at such low pressures raises the possibility of air (a noncondensable gas) leaking into the condensers. Experimental studies show that the presence of noncondensable gases in the vapor has a detrimental effect on condensation heat transfer. Even small amounts of a noncondensable gas in the vapor cause significant drops in heat transfer coefficient during condensation. Eor example, the presence of less than 1 percent (by mass) of air in steam can reduce the condensation heat transfer coefficient by more than half. Therefore, it is common practice to periodically vent out the noncondensable gases that accumulate in the condensers to ensure proper operation. 

Chemical Reactions. Products from gas-phase chemical reactions can also be trapped in rare gas matrices, and those products which absorb light can be studied by optical spectroscopic techniques. For example (31), the products from a low pressure 1 mm. of Hg) atomic flame of oxygen atoms plus acetylene were allowed to leak through a small oriflce in a borosilicate glass reaction chamber, where they were mixed with an excess of gaseous krypton at 1(H mm. of Hg pressure. The mixture was condensed on a quartz window cooled to liquid helium temperature. The only detectable small free radical found was HCO, but it was present in considerable quantities. Similar experiments by Harvey and Brown (23) showed that HNO could be easily produced and trapped from the gas-phase reaction of hydrogen atoms plus nitric oxide. 

The pressure measurements should always be done by capacitance manometers (CAs) and not by thermal conductive gauges. TM depend on the gas mixture (water vapor and permanent gases) and are not reproducible enough for BTM measurements details are given on pp 327, 328 in [2]. For leak testing no special equipment specifications are required. The leak rate for the chamber, e.g., <1 x 10 mbarL/s, and for the condenser, e.g., <1 X 10 mbarL/s, should be specified since it might be helpful to measure the chamber and condenser separately. The maximum tolerable leak rate in the two examples is <1 x 10 mbarL/s, if the DR data at 0.1%/h should have an error <10%. If a helium leak tester is not available in production, it should be specified for quotation. 

Leak rates chamber with cold and heated shelves and condenser with cold surfaces each < 1 X 10 mbar L/s. To measure DR data of 0.2 %/h of both products with an influence of the leak rate smaller than 0.002 %/h, the leak rate for the example products, and a chamber of 100 L, a leak rate < 10 mbar L/s would be sufficient (for details see pp 95-98 in [4]). 

EVS were put to work on real systems on several occasions in the oil and gas industries for two main reasons. The 1st reason was the critical nature of many operations associated with the transport of gas and other petroleum products, and the 2nd is the predictability of localized corrosion of steel, the main material used by the oil and gas industry. Meany has, for example, reported four detailed cases where extreme value distribution proved to be an adequate representation of corrosion problems in underground piping and power plemt condenser tubing [15]. In another study, data from water injection pipeline systems and from the published literature were used to simulate the sample functions of pit growth on metal surfaces [Id]. It was concluded that maximum pit depths were adequately characterized by extreme value distribution, that a Gaussian distribution could model corrosion rates for water injection systems, and that an exponential pipeline leak growth model was appropriate for all operation regimes. 

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