Monitoring flow-rate changes of a plurality of fluid streams

摘要

Changes in the flow-rates of each one of a plurality of fluid streams which pass from respective conduits (13) to a common conduit (12) are monitored by taking a representative sample of fluid from a sampling point (16) of the common conduit, determining the change in composition of at least key components of the sample relative to a preceding sample obtained in the same manner, and computing from the change in composition the composition of the fluid stream whose flow-rate has changed, so that the fluid stream can be identified by reference to a library or database of fluid stream compositions. When the fluid streams are gases (e.g. gases to be flared at an oil refinery or chemical process plant), each sample may be analyzed by a gas chromatograph (18) at predetermined intervals and the fluid stream whose flow-rate has changed may be identified automatically by comparison with a database or library (22) of fluid streams. The thus identified fluid stream may be recorded and/displayed (19). The monitoring may be completely automatic. The method and apparatus of the invention avoid the necessity to provide flow-monitoring equipment in each conduit (13).