Experimentation column
Recent accidents have highlighted the lack of reliable data on the behaviour of products in the aqueous phase. In 2003, Cedre therefore decided to design and construct a new experimental tool to study the time taken by a pollutant in the water column to surface or settle. This equipment can be used, for example, to simulate the solubilisation kinetics of a product as it rises up through the water column from tanks of a grounded vessel in order to correctly assess the threat for responders and the environment, as well as the value and the possibilities of response. By extension, it can also be used to study the trajectory of bubbles or an object rising to the surface or settling to the bottom in the water column.
Characteristics
This experimentation column was installed in Cedre’s
experimentation hall where it can be supplied with seawater
at a controlled temperature.
Its dimensions (5 m high and 0.8 m in diameter)
make it a unique tool. It is comprised of six sides of
which three are transparent and three are made of stainless
steel. It is fitted with a watertight lid, 5 valves for
regular sampling of the water column at different heights
and a pipe to inject the product in question located at
the bottom of the column which may be fitted with nozzles
of various diameters to simulate varying leak rates. It
also includes an atmosphere sampling system at the top
of the column to assess the transfer kinetics at the air-water
interface.
Usage
Substances
can be injected into the water column either from the
base or from the surface. However, the protocol used to
study the solubilisation kinetics remains the same in
both cases and is based on the principle of filming and
image processing. First, a video and a series of photographs
are taken during the movement of the pollutant in the
water column.
These images are then saved in a computer-based
format. This data is processed using specialised software
to study the evolution of the size of droplets according
to their movements, both in terms of their speed and their
trajectory.
The
experimentation column
IT
tool for data acquisition and processing