In the process of operating pipelines for transport, and vessels and tanks for storage of natural gas, petroleum and petroleum products, a large variety of chemicals may be used to protect the integrity of these vessels. These chemicals can act as biocides, corrosion inhibitors, scale inhibitors, anti-foaming agents, emulsion breakers, and hydrate inhibitors to name a few.
The chemicals are added in small, but effective amounts where effectiveness may in many cases be maintained below a one percent concentration. These chemicals tend to be expensive so small amounts are good for cost minimization and also avoid displacing the fluids such as oil, gas or fuels in the pipeline. However, small effective amounts are very slightly more than amounts that are inadequate and ineffective. These protective chemicals are typically consumed at non-linear and unpredictable rates so trying to maintain a minimum, but yet effective amount is very difficult. There are two fundamental challenges for efficient use of these types of chemicals. First, equipment that is reliable and cost effective for measuring chemical concentrations below one percent are generally unavailable or impractical. Secondly, since the chemical concentration may fall below the threshold for effective amounts without warning, it is common for pipeline operators and owners of vessels and storage tanks to simply use quite a bit more than necessary as a precaution against not having enough. Since the chemicals are very expensive, any over-use of the chemicals can directly and substantially impact the bottom line of the end-user. Therefore, it is highly desirable to have a mechanism to closely monitor the amounts of the chemicals to make sure that a minimum effective amount is present in the storage vessel or along the length of a pipeline at all times.