Resumo:
The use of fuel oils for energy generation in thermoelectric plants makes an important
contribution to the Brazilian power grid, especially during periods of lower water abundance.
The fuel oil used by some power plants is a by-product of petroleum refining, and may
contain contaminants that are harmful to the machinery when present in considerable
amounts. In this context, the present work brings the development of a system for online
monitoring of the processes of supplying thermoelectric power plants with heavy fuel oil.
This system allows the visualization of the flow rate and the amount of water contained in
oil, since this is one of the main contaminants that can be found in this type of fuel. Its
application aims to provide the plant with more detailed knowledge about the purchased fuel,
as well as allowing the interruption of supply operations in the event of an irregular product.
For the implementation of the system, a multi-path ultrasonic method for flow measurement
is used, as well as a capacitive method for identifying the water content. This work presents
the development of electronic circuits for performing the proposed measurements, including
an innovative circuit for measuring capacitance through an oscillating current source. The
individual elements of the system are tested and calibrated, ultimately leading to the
assembly and installation of a working prototype in a thermoelectric power plant.
