The challenge
Accurately measuring rheology
Rheology is the process of gauging the deformation and flow of matter, with a focus on non-Newtonian fluids and the flow of solid plastics. The rheology of process and tailing streams has an impact on how they are transported and their performance throughout the production line.
Rheology can also be used as a proxy method of measuring the physical and chemical changes within the substance of interest.
Accurate rheology measurements allows operators to tighten the process control parameters, optimising the amount of product processed while reducing production time.
Our response
Simplifying a complicated procedure
Our researchers have designed a new monitoring software known as the Online Rheometer (iOR) which measures the rheology of a fluid of interest by taking a side stream and measures the pressure drop generated over a pipe of known dimensions for a series of known volumetric flow rates.
The inlet to the iOR is attached as a bypass of the thickener underflow (or other unit operations) before the underflow pump, ensuring that the rheology measured is as close to the condition inside the thickener as possible and not sheared excessively.
The iOR provides the means to collect data in real time allowing a greater understanding of the process conditions. This can be seen in the monitoring of thickener underflow rheology.
While thickeners often use underflow density as a control parameter, rheology is more relevant to the performance of a thickener, and provides more relevant data for underflow transport.
The advantages of the system also include the capacity to calculate rheology on substances which aren’t homogeneous, can operate autonomously over a long period, an adjustable shear rate range of 0.5 – 100 and data collected via the iOR can be accessed remotely online.
The results
Simpler, easier and faster
Several commercial instruments exist to measure rheology online, however these units are not well suited for handling multi-phase flows. Our online rheometer has no protrusions into the flow, so wear is reduced.
It doesn’t require velocity profile measurement which is problematic in solids laden flows.
The advantages iOR provides would allow organisations to tighten their control strategy and lower the capital costs of running such a procedure.