Improving the Sensitive of Industrial Acid-Dew Point Sensors for Flue-Gas Analysis

The project will run in close collaboration between CBE, UoS and Land Instruments who want to realise the full market leading potential of an enhanced sensor. As such, this PhD project will span many TRL levels - approaching a final product at the end of project. Initial research will focus upon three concurrent themes:
#1 - Electrode Geometry. Electrical conductivity is measured between a pair of platinum electrodes mounted on the end of glass thimble (25mm diameter). One is also a thermocouple. They are made via traditional glass blowing methods,
which despite the glassblowers skills, produces electrodes of variable (and large - mm) separations. To improve sensitivity, we need to make the electrodes larger and more interdigitated, and closer together. Rather than using traditional glass blowing to position the platinum electrodes in molten glass we will use metal evaporation and shadow lithography to coat and make a range of electrode geometries onto a custom "base" electrode, thus modifying its electrode geometry. The student will quantify the sensitivity as a function of a separation distance between electrodes and their overlap distance.
#2 - Modern Manufacturing Techniques. The corrosive environment means electrodes are made of platinum. To produce platinum patterned electrode surfaces on glass we will investigate the use of modern materials processing. This
includes Pt-ink screen printing and inkjet printing, the latter allowing for rapid prototyping (this has been discussed with Patrick Smith - MechEng). Advances in laser etching, micromachining, and welding will also be explored as
this offers routes to precise and reproducible glass thimble geometries and production, with the possibility for etching of tracks and through-holes for electrodes (cf. glass microfluidic devices).
#3 - Artificial Chimney/Flue Gas Stack. To validate the sensors performance and commissioning of final prototype products we need a stable and reproducible artificial chimney of known acid-dew-point. We have already developed a crude
system based upon a hot-airgun, acid solution, and glass tubing which will be developed and commissioned and used throughout the research programme.
#4 - Prototype Testing. As this project focusses on improving an existing sensor, the route to full prototype testing is relative easy and the best sensors fabricated throughout the project can be incorporated into existing probe assemblies and electronics for real world testing. Land routines tests probes in China in coal fired power stations.
#5 - Combinatorial Sensors. New fabrication routes allow for more than one sensor to be included in a sensor. Combining multiple sensors with a temperature gradient will allow for quicker measurement and entirely novel and market leading sensors.
#6 - Understanding the Commercial and Environmental Impact. This product falls under the product group of "Power, Combustion, Environmental" of Land Instruments and the impact these improved sensors have impact both on the environment and economically though energy efficiency and legislation and control. To better understand this impact full environmental and techno-economic analysis the improved sensors can help direct will be conducted. This will be led by
the second supervisor.