At low temperatures, the purity of chlorine cannot be increased
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The turbine sampling port is located on the liquefaction frame, on the heat exchanger of a certain unit (where the temperature of chlorine is around 40 degrees). The pipeline is exposed to the air for about one meter in length; there are three valves in total at this location, all of which are closed after sampling. Once winter arrives and the temperature drops below zero, when samples are taken on-site to analyze the purity of chlorine, the purity level cannot reach the desired 99.4%; with low temperatures, it only reaches around 80%. Further replacement processes are required, usually three or four times, in order to increase the purity level. I also considered whether it might be a problem with the absorbing solution; I heated it before preparing the sample, and it was still warm to the touch at the site. Does low temperature have an effect on chlorine gas?
The physical properties of chlorine change with temperature, especially at lower temperatures. During gas sampling and analysis, low temperatures can affect various aspects, leading to unsatisfactory results in chlorine purity tests. The following are some possible influencing factors: 1. **Condensation issues**: At low temperatures, chlorine or other accompanying gases may condense into liquids, affecting the flow of gas within the pipelines and the representativeness of the samples taken. When the gas flows through the cooler sections, part of it may condense, preventing an accurate acquisition of a complete gas sample. 2. **Adsorption on the inner wall of the pipeline**: Low temperatures may enhance the adsorption of chlorine gas by the material forming the inner wall of the pipeline, resulting in the gas not being entirely in gaseous state at the time of sampling and thus reducing the purity of the gas used for analysis after sampling. 3. **Chemical reaction rate**: If sampling and purity analysis involve chemical reactions, a decrease in temperature may lead to a reduction in the reaction rate, which in turn can affect the test results for chlorine purity. 4. **Equipment failure or errors**: Low temperatures can also affect the accuracy and reliability of instruments, including the sealing performance of sampling valves and the calibration of analytical equipment, thereby impacting the test results. To address the issue of low temperatures making it difficult to achieve the desired results in chlorine purity tests, the following measures can be tried: – **Equipment insulation**: Insulate the pipelines, especially those exposed to air, to prevent chlorine from condensing within them. - **Instrument calibration**: Recalibrate the analytical instruments under low-temperature conditions to ensure the accuracy of the test results. - **Process optimization**: It may be necessary to optimize the sampling process, such as shortening the length of the pipelines, increasing the sampling flow rate, or cleaning the pipes regularly to reduce adsorption on their inner walls. - **Heating measure**: Heat the sampling port to ensure that chlorine does not partially condense due to low temperatures during sampling. - **System inspection**: Examine the entire sampling and analysis system, including all valves and connection points, to ensure there are no leaks and that the samples remain free from contamination by external air throughout the process. - **Technical consultation**: If the problem persists, it may be necessary to consult professional experts in chemical analysis or process engineering in order to identify the specific cause of the issues with chlorine purity testing and develop appropriate solutions. By taking into account the above factors and measures, you may be able to improve the accuracy of testing chlorine purity under low-temperature conditions in winter. .