EXPLOSIVE GAS MONITORING METHOD AND APPARATUS

摘要

Monitoring of the recirculated atmosphere of an oxygen pulping reactor to determine when the inflammability level of combustible gases in the reactor atmosphere has reached a predetermined percentage of the lower explosive limit (LEL) of the reactor atmosphere in terms of combustible organic vapors and carbon monoxide is disclosed. Continuous or discrete samples of the reactor atmosphere are taken at spaced regions, and the samples are applied to: (1) flamed ionization detectors, which determine theconcentration of combustible organic vapors (e.g., aliphatic, olefinic, aromatic, acetylenic, alcohols, aldehydes, ketones, etc.) in the samples; and, (2) carbon monoxide analyzers, which determine the concentration of carbon monoxide in the samples. The outputs of the flame ionization detectors are calibrated in terms of percent LEL for the contributing combustible organic vapors and, thus, provide percent combustible organic vapor LEL information. The outputs of the carbon monoxide analyzers are calibrated in terms of percent LEL based on the carbon monoxide in the samples. The outputs of the flame ionization detectors are compared and the highest percent output is applied to an alarm and recording subsystem. These outputs are also compared to determine if they are close to one another. If the comparison indicates that a substantial difference exists, a differential sensor activates a further alarm to denote a wide variance that may indicate a faulty detector channel. Similarly, the outputs of the two carbon monoxide analyzers are compared and the highest percent output is applied to an alarm and recordingsubsystem. Also, if the outputs are substantially different a differential indicator is activated. In addition, in an alternative embodiment, the highest flame ionization output is summed with the highest carbon monoxide analyzer output and the result is applied to a controller that continuously controls the position of a vent valve, as well as to an alarm and recording subsystem. Finally, an oxygen analyzer is provided for measuring the oxygen concentration of at least one of the reactor atmosphere samples.