Page 58 - 00. Complete Version - Progress Report IPEN 2014-2016

58 Application of Ionizing Radiations | Progress Report

tectors, the five tungsten-shielding-cases and columns has long been recognized as a poten-
collimators systems are mounted on two MDF tial source of maldistribution and it has been
plates of 20 mm thick and, thus, they are easi- studied extensively. A third-generation gam-
ly adaptable to different industrial objects. The ma transmission tomography system, devel-
source shielding-cases were built with tung- oped at IPEN, was used to evaluate the liquid
sten, instead of lead, in order to make them as distribution of a Rashig ring random packed
small as possible. They were designed to con- column, at two different water flows: 2 and 6
tain up to two radioactive sources with differ- liters/min. For each water flow, the measure-
ent energies and to have a system with step- ments were carried out at nine column heights.
per motor controlled by computer, maintaining The liquid-gas holdup was determined by the
the operators at a distance from the radioac- reconstructed images. The distribution of the
tive sources. In this CT, each of the seventy de- Rashig rings, as well as the position and the av-
tectors is connected to a set of multichannel erage accumulated amount of the water con-
type electronic acquisition board, developed centration, among the Rashig rings, could be
at our Laboratory. The developed tomography determined, even at a low temporal resolution
system is capable of generating real-time im- of the system of 8.8 hours. The regions of ac-
ages of the interior of industrial process tow- cumulated water concentration were similar
ers or tubes, with fast transients, without par- for the water flow velocities, at 2 and 6 liters/
alyzing the production. This non-destructive min. However, the average accumulated wa-
analysis system contributes to achieve high ter concentration for 6 liters/min was higher,
productive and optimized yields in industri- compared to 2 liters/min. The spatial resolu-
al processes, as well as contributing to the re- tion of the tomography system determined by
duction of environmental impact, inherent to the modulation transfer function (MTF) anal-
industry activity. The beneficiaries of the re- ysis was of 1.45 mm.
sults of this project are the oil refining indus-
tries and their derivatives and basic chemi- Ionizing Radiation
Application in Food and
cal industries.
Gas-Liquid Distribution in the Random Agricultural Products

Packed Column using a third-generation
gamma tomography News aspects on food irradiation and analyses
of natural biocompounds in edible flowers

Random packed distillation columns are used,
extensively, in chemical and petrochemical We highlight our objectives in the studies of
industries to perform highly efficient process ionizing radiation in eatable flowers and start
separation. Liquid flow distribution has been a with new studies to establish minimum and
major concern when scaling up random packed maximum amount of 2-Alkylcyclobutanones
columns. The liquid distribution in random (2ACB) to endorse the safe consumption of irra-
packed columns is not often uniform, even diated fat food. There is extensive research on
when the liquid is uniformly introduced into the most suitable technology for food preser-
the column. The knowledge on porosity vari- vation, which does not compromise the qual-
ation (gas holdup) of random packed columns ity of its bioactive compounds and toxicity of
is useful for understanding the fluid dynamics. irradiated foods. In this way, radiation process-
The porosity variation in the random packed ing has been shown to be an effective alterna-

Instituto de Pesquisas Energéticas e Nucleares