Due to the characteristics of piping, process, continuity and full closure of chemical production operations, process personnel need to observe the various types of process parameters, such as reaction temperature, material flow, vessel pressure and liquid level, ingredients, etc. to determine whether the process is normal, the quality of the product is qualified, according to the meter instructions to increase or reduce production, even parking. Instrumentation malfunction caused by abnormal indication, most from the field instrumentation, so the maintenance of on-site instrumentation operation is particularly important. field instrumentation parameters are generally divided into four categories: temperature, pressure, flow, liquid level. According to the different measurement parameters, the fault of different field meter is analyzed.
The concrete ideas are:
Before analyzing the faults of the on-site instrumentation system, we should understand the changes of the load and the parameters of the raw material to the field operator, view the record curve of the fault meter and carry out the comprehensive analysis to determine the cause of the instrument malfunction. If the instrument record curve is a dead line, or record the original fluctuation curve, now suddenly become a straight line, the fault is likely in the instrument system. Because the current record meter is mostly DCS system, the change of parameter can react very sensitively to the computer. At this time, the process parameters can be changed artificially, and the curves change. If not change, the basic can be concluded that the instrument system is a problem, such as the curve can track the change of process parameters, basically can exclude instrumentation system failures. If the process parameters are changed, the record curves are found to mutate or jump to the maximum or smallest, and at this time the fault is often in the instrument system. The failure occurs before the meter record curve has been normal, the record curve after fluctuation becomes no rule or control system is difficult to realize automatic control, even manual operation can not control, at this time the failure may be caused by improper process operation. When it is found that DCS display meter is abnormal, it can go to the scene to inspect the indicator value of the parameter field meter, if the difference is very large, it is likely that the instrument system malfunction.