Methanol (Controlled Stream)
Ratio Control System for Air Methanol It is recommended that the inlet temperature and pressure of the feed mixture be indicated and recorded. Recording process conditions is also recommended.
6.2 Heat Exchanger Heat exchangers are inherently stable operating units. Extensive instrumentation is therefore not usually proposed. However: control on flow parameters is necessary and proper indication and recording of the inlet and outlet conditions is recommended. Temperature measuring elements and heat-exchanger installation should be placed as close as possible to the active heat exchange surface, consistent with requirements for adequate mixing of the process stream. A thermal element installed several feet downstream of the exchanger in the process .pipeline will cause a time delay in the control system. This time delay or distance-velocity lag has a particularly noticeable effect on control performance. Thermocouples in protective thermal well are proposed' as temperature measuring elements. Particular care must be taken to minimize 97