Why Is Industrial Tomography Important and What Are Its Uses?

Posted by Enurga on September 13th, 2019

When we talk about tomography, people generally associate it with medical X-ray tomography, famously known as Computed Tomography (CT) scanning. Tomography is a broader term and also encompasses other industrial processes and measurements apart from medical diagnosing and evaluation. 

The term “tomography” comprises of two Greek words – “tomos” which means sharp in the sense of making sharp cut and “graphein” which means to write. Industrial Process Tomography, therefore, refers to cross-sectional imaging of parameters of industrial processes, which are a function of time. 

The primary purpose of using industrial process tomography is to obtain several measurements around the multiphase process periphery and use this data to reveal the cross-sectional distribution of process components in time and space. Such information helps in designing and optimization of industrial processes and process equipment and, thereby, improves the accuracy of multiphase system measurements.

Basically, with the help of tomographic imaging, multiple measurements are taken at different angles or directions through the object being investigated and an image is reconstructed by producing a 2D distribution of parameters. Then, several 2D images can be stacked together sequentially to obtain a 3D image. It is a non-intrusive technique which we can use to measure phase distribution in multiphase equipment without interruption of normal operations. It provides us a way to quantify multiphase opaque flow fields, which otherwise is impossible to do so.

Multiphase systems are used in various modern industrial and environmental processes, for instance, for industrial production of polymers, food, pharmaceuticals, etc. Such systems consist of gas-liquid, liquid-solid, gas-solid, gas-liquid-solid, and liquid-liquid-solid-gas mixtures and are used as major processing units of modern industry. 

Such mixtures need to be transported, mixed, and separated through pipes, tanks, and settlers/crystallizers/distillation columns, respectively. They have to be reacted in stirred slurries, bubble columns, and other reactors. In each case, there is no sufficient theory to predict the phase distribution, flow pattern, and mixing. 

If these process units can be designed and operated more efficiently, there will be substantial savings in capital expenditures and operating costs. Since these systems are difficult to measure and control with conventional instrumentation, computed tomography is employed.

For example, infrared emission tomography and/or x-ray tomography systems are used to perform non-destructive evaluation of plastic components and obtain soot mass concentration in diesel particulate filters. 

On the other hand, if we talk about infrared emission/absorption spectroscopy systems, they are used for determining the local particulate and gas species’ concentrations and temperatures in a turbulent or laminar reacting flow. Generally, such measurements are obtained in the infrared wavelengths. 

Fortunately, there are advanced tomography and spectroscopy systems available in today’s time for measurement of parameters such as soot mass concentration, gas concentration, and flame temperature which we cannot obtain through other means.