Artificial Neural Network and Neutron Aplication in a Volume Fraction Calculation in Annular and Stratified Multiphase System

Multiphase flows, type oil–water-gas are very common among different industrial activities, such as chemical industries and petroleum extraction, and its measurements show some difficulties to be taken. Precisely determining the volume fraction of each one of the elements that composes a multiphase flow is very important in chemical plants and petroleum industries. This work presents a methodology able to determine volume fraction on Annular and Stratified multiphase flow system with the use of neutrons and artificial intelligence, using the principles of transmission/scattering of fast neutrons from a 241Am-Be source and measurements of point flow that are influenced by variations of volume fractions. The proposed geometries used on the mathematical model was used to obtain a data set where the thicknesses referred of each material had been changed in order to obtain volume fraction of each phase providing 119 compositions that were used in the simulation with MCNP-X –computer code based on Monte Carlo Method that simulates the radiation transport. An artificial neural network (ANN) was trained with data obtained using the MCNP-X, and used to correlate such measurements with the respective real fractions. The ANN was able to correlate the data obtained on the simulation with MCNP-X with the volume fractions of the multiphase flows (oil-water-gas), both in the pattern of annular flow as stratified, resulting in a average relative error (%) for each production set of: annular (air= 3.85; water = 4.31; oil=1.08); stratified (air=3.10, water 2.01, oil = 1.45). The method demonstrated good efficiency in the determination of each material that composes the phases, thus demonstrating the feasibility of the technique.

Evaluation of Gaseous Fluid Dispersion Through Packed Bed Using Radiotracers Technique

In this study, it was developed a methodology for the determination of the dispersion of a gaseous tracer in porous media using the radiotracer technique. In order to evaluate several porous media, a cylindrical filter was constructed in PVC and connected to a system with constant flow. Inside this unit silica crystals (16-20) mesh was used as porous media and CH3Br (Methyl Bromide) marked with 82Br was used as radiotracer. An instantaneous pulse of tracer was applied in the system entrance and registered by two NaI (3x3)” scintillation detectors located one before and the other after the filter. The curves produced by the radioactive cloud and recorded by the detector were analyzed statistically using the weighted moment method. The mathematical model one considered as great dispersion of tracer was used to evaluate the flow conditions inside the filter system. The results show us that the weight moment method associated with radiotracer techniques is useful to evaluated an industrial filter and allows to measure the residence time distribution, τ, and the axial dispersion, DAB, gas in a porous medium.