Development of diagnostic techniques for the optimisation of steam and condensate loop efficiency and reliability

Steam dryness is a critical parameter in a steam system, impacting both the efficiency and quality of processes that utilise steam. It refers to the amount of water contained within the steam eg, if steam contains 10% water by mass, it's said to be 90% dry, or have a dryness fraction of 0.9. The dryness of steam is particularly important in applications that are sensitive to this parameter. For

example, the manufacture of tyres requires consistent steam dryness for optimal results. In sterilisation processes a dryness between 0.95 to 1 is required for metal loads, and 0.9 to 1 for other loads (BSEN285). In enhanced oil recovery from tar sands, a steam dryness between 0.5 and 0.8 is used. Steam separators are often used to ensure the dryness of steam remains within target. These devices

work by using centrifugal force, taking advantage of the difference in the specific gravities of liquid and gas to separate the two. However, without real-time precise measurement, there is no reliable way to know the exact value of steam dryness at any point in the system. This can be particularly problematic

when industry applications use varying levels of insulation and pressure drops along their steam lines. Accurate measurement of steam dryness is also crucial when metering a steam flow to make an accurate energy assessment of the system. Furthermore, the efficiency of steam separators over a large range of conditions cannot be guaranteed without accurate steam dryness measurements.

Despite the importance of measuring steam dryness, there is a lack of real-time devices that can accurately measure this parameter. The industry currently relies on acquired experience and occasional calibration exercises that are time-consuming, costly, and limited to small sections of the whole steam line.

New sensor technology is urgently needed by the steam industry to enable the real-time measurement and monitoring along the complete steam line, and improve both energy efficiency and process quality. The studentship will aim to develop new optical/acoustic diagnostic techniques that can provide real-

time measurement of steam dryness. The specific objectives will be to: 1. Set up a new high-pressure steam test facility in the TFMRC. 2. Research potential techniques for steam dryness quantification by optical and acoustic sensing 3. Test the proposed diagnostic technique(s) to quantify their performance

4. Explore signal processing approaches to calibrate and augment the measured data Methodology The methods build upon a feasibility study conducted at Spirax-Sarco's Technology Centre in Cheltenham in July 2023. The Lead Supervisor performed optical measurement on their high-pressure line and recorded data for a range of steam pressures, dryness, flow velocity, and flow configuration.

The feasibility study demonstrated that long-range optical microscopy could be used to quantify the size, shape, velocity and acceleration of water droplets in high-pressure steam lines. Spirax-Sarco will organise, fund and install a new high-pressure Steam Testing Facility (STF) within the TFMRC. To the best of our/Spirax-Sarco's knowledge, Sussex

would be the first UK university to host such a facility. After commission of the STF by our industry, the project will focus on the development of steam dryness sensing techniques. While the specific measurement techniques to be developed will emerge as part of the studentship, we anticipate that the PhD will build upon our preliminary findings and

consider: - Machine vision approaches to quantify: a) the local water droplet size and velocity distribution in steam, and b) the spatial and temporal distribution of condensates in the pipeline - Laser diffraction and scattering to measure the droplet size distributions that cannot be resolved optically.

- Light extinction to quantify the optical density of the steam Ultrasonic sensing to measure the speed of sound in steam