Discontinuous gas analysis method and equipment thereof

Abstract

This invention discloses one interval gas analysis method, which comprises the following steps: a, closing second valve fixed on first one and opening first one connected to the high pressure device with the gas inside filled with first and second valves capacitor as sample; b, closing first valve and opening second valve with first storage through second valve downstream; c, releasing the sample gas through second valve; d, analyzing released sample gas to get sample parameters. This invention also discloses one device to exert above method.

Description

technical field [0001] The present invention relates to gas analysis, more specifically, to an intermittent gas analysis method and device. Background technique [0002] In the field of chemical production, it is often necessary to analyze the concentration of various process gases. For example, in urea synthesis, it is necessary to keep the ratio of ammonia and carbon dioxide in the synthesis tower within a certain range, so it is necessary to analyze the concentration of ammonia and carbon dioxide. The above-mentioned reaction process is usually carried out in a high-pressure environment, such as above 150 atmospheres, which requires a method and device that can measure the gas concentration in a high-pressure environment. [0003] In order to measure the gas concentration in a high-pressure environment, the off-line analysis method after sampling is usually used. The specific method is: connect a valve to the high-pressure device, and when sampling is required, connect a ...

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Problems solved by technology

However, this method requires manual sampling of high-pressure gas, even toxic gas, which has great potential safety hazards and high labor costs; due to the off-line analysis after sampling, it takes a long time, the measurement lags seriously, and the reference value of the measurement results is small; at the same time, the sampling frequency Low, cannot effectively monitor the gas concentration change in the high-voltage device under test

[0004] In order to solve the inadequacy of online analysis in the above technical solutions, there is currently an online analysis method: install a pressure reducing valve on the high pressure device under test, use this pressure reducing valve to reduce the high pressure in the high pressure device to normal pressure, and then reduce the normal pressure to normal pressure. The compressed gas is sent to the gas analysis instrument for analysis

However, since the sample gas flow rate required by the gas analysis instrument is relatively small, and there is still a large proportion of decompression, the vent aperture of the decompression valve must be adjusted to a small size in this working mode. Large particles of dust or debris of device materials can easily block the pressure reducing valve; in addition, in some devices, the process gas to be measured will crystallize during the decompression process, blocking the pressure reducing valve, such as in urea synthesis During the measurement of the gas-phase ammonia-carbon ratio in the device, the temperature of the ammonia and carbon dioxide in the high-pressure synthesis tower is greatly reduced during the process of decompression by a large proportion, thus forming ammonium carbamate crystals to block the pressure relief valve

Obviously, this method has a large maintenance workload and cannot well meet the needs of gas analysis in high-pressure devices

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