Detection of impurities in fluid flowing in refinery pipeline or oil production operations using nuclear techniques

A method and apparatus were developed for determining chlorine in fluids such as crude oil at wellheads or loading docks, refined product, or refinery feedstock or waste water. The fluid is bombarded with fast neutrons giving rise to thermal neutron capture gamma rays. The chlorine content is determined from the energy spectra of the thermal neutron caputre gamma rays. If the salinity of the salt water is known, and all the chlorine in the fluid is present as sodium chloride, then the salt water content in the fluid can also be determined. The sulfur content is determined from the gamma ray spectra simultaneously with the chlorine content. If the fluid contains a gas homogeneously mixed, then the percentage of gas or gas/oil ratio can be determined. The measurements are unaffected by the velocity and volume flow rate of the crude oil stream. The chemical source for the thermal neutrons is less expenisve and requires less maintenance than evacuated-envelope accelerator-type neutron generators. (DN)