Dmitri Nešumajev, Senior Research Scientist at the Department of Energy Technology, is one of the three scientists at the Tallinn University of Technology who may be elected Academician of the Estonian Academy of Sciences this year.
At the conference of academician candidates on 2 November, Nešumajev provided an overview of his research activities. The title of his presentation was ‘Through research to industrial applications’.
The focus of Nešumajev’s research is heat transfer enhancement. He has carried out both experimental research and mathematical modelling, from laboratory scales to 250 MW boilers installed in Narva.
His research is highly pertinent at the moment, as the results of his research allow greenhouse gas emissions to be reduced and are thus directly linked to the efforts of achieving carbon neutrality in the oil shale sector. There are several ways to achieve this: reducing the consumption of materials and cost of equipment, increasing their efficiency and operational reliability. ‘I have dealt with quite a wide spectrum of topics,’ Senior Research Scientist Nešumajev said. ‘The results can be implemented in many ways, from solar collectors to nuclear reactors.’
Nešumajev’s first research topics were primarily related to heat transfer. He first researched the effect of thermophysical properties of the heat transfer surface on heat transfer. He came to the conclusion that material properties may affect the intensity of heat transfer up to 20%.
He then conducted an experimental study to research the effect of surface roughness on heat transfer. The study revealed that the intensity of heat transfer may increase faster than frictional force. This research also had a practical application: it was the basis for the creation of the device for convective heat transfer intensification, i.e., a turbulator. In this case, the reduction in fuel consumption is equal to the reduction in CO2 emissions. He also studied the devices for convective heat transfer intensification in industrial conditions.
He then focused his research on fuel combustion in large-capacity CFB boilers. On his initiative, the properties of thermal power equipment at variable loads were determined.
According to Nešumajev, one modern solution for reducing CO2 emissions is combustion in an environment enriched with oxygen. In this technology, CO2 can successfully be captured from other components and then either stored or utilised to its maximum extent.
A techno-economic assessment of CCS technology possibilities in shale oil production was also conducted. In the assessment, both post-combustion technology and oxy-fuel combustion technology were analysed. ‘It is possible to achieve 100% CO2 capture efficiency,’ based on Nešumajev’s assessment. ‘However, if we were to burn 50% of biomass with oil shale, we could even achieve so-called negative emissions.’ The same methods were used by scientists in the shale oil production assessment.
When speaking about possible activities as an academician, Dmitri Nešumajev pointed out the need to shift to carbon-neutral energy production. ‘This is the biggest challenge I am facing as an energy technician,’ he said.
Watch a video of the presentation HERE.
Dmitri Nešumajev was born on 25 October 1974. After graduating from the Kehra Upper Secondary School, he continued his education at the Tallinn University of Technology. It was here where he became a thermal engineer and received his Master of Science in Engineering degree and Doctor of Engineering degree. His doctoral thesis was titled ‘Experimental and Numerical Investigation of Combined Heat Transfer Enhancement Technique in Gas-Heated Channels’. Nešumajev has also spent all of his professional career at the Tallinn University of Technology.