the bob cat

the bob cat

Hasil (Bahasa Indonesia) 1:

kucing bob

Hasil (Bahasa Indonesia) 2:

Because hydrogen has the potential to be explosive when mixed with oxygen, it is important to know the purity of the hydrogen gas in air during generator operation or in a stand-by mode. Hydrogen gas analyzers are calibrated to display the purity of air in hydrogen during generator operation. If a given purity analyzer displays 98 percent pure hydrogen, the analyzer assumes that 2 percent of the gas is air. In fact, the impurity can be a combination of air, carbon dioxide, water, and oil vapor. When the impurities are other than air, there is an element of inaccuracy introduced to the analyzer output.

If the carbon dioxide has been thoroughly purged from the generator prior to operation, the likely contaminants then include air, water, and oil vapor. Many hydrogen purity analyzers also include dryers upstream to remove water and oil vapor prior to entering the hydrogen purity analyzer. In these instances, it is more likely that the impurities measured by the analyzer are indeed air.

Operators of hydrogen-cooled generators need to be aware that just because hydrogen purity may display a high reading, this does not mean that the generator is dry. The dryers installed upstream of generator gas analyzers eliminate water as a contaminant and a potential signal of impurity.

As an example, dew point measurements taken at many gas turbine sites over the last several years revealed high purity readings on the purity analyzers that did not coincide with the measured dew points. Typical dew points ranged from +20°F to +70°F, while the purity analyzers usually showed 99 percent and higher. Further investigation of the purity analyzers, and discovery of the upstream dryers, explained the discrepancy.

This can be a particular problem on generators used for peak load conditions. Some generators are equipped with internal electric heaters to keep relative humidity of the hydrogen coolant low, but many utilities are reluctant to operate these heaters for safety reasons.