Pulverised burners

Research overview >

In this area, we are 

• investigating how reacting particles entrained to jet flows behave near the burners, and

• developing forced particle dispersion methods to reduce soot from biomass gasification

Many combustion and gasification technologies for biomass use "pulverised burners". Small particles are transported to the reactor by gas (pneumatic transport) and heated quickly to convert quickly in the reactor. We have a working hypothesis that flame dynamics, emissions, and other important performance indicators are strongly affected by how fuel particles spread inside the reactor upon injection. This is because the local densities of particles will change the local reaction conditions to modify how chemical reactions progress.

For this reason, we are investigating the behaviour of fuel particles near the burner outlet. First question is how fuel particles spread when they are injected into a large volume of vessels at high speed. Another question is how fuel particles change their sizes, how they release gases, and if and how the trajectory of particles are affected by the reactions. We are using high-speed photography (up to 5000 images per second) to follow the movement of particles to answer these questions.

Then, we also want to apply the knowledge to optimize or develop a new design or control techniques to improve the performance of combustion and gasification (e.g. soot reduction in entrained flow gasification process). They key issue here is to actively disperse fuel particles. We have been trying several effective methods such as swirl flow, synthetic jet (acoustic wave), bluff body, and so on. We are investigating how such various techniques can change the dispersion of fuels and improve the reactor performances. 

The methodology is commonly called process intensification (enhancing mixing of gas and solid flows to improve reactor performances) in chemical engineering field, but it has been rarely applied to gasification or combustion field. The results of the project will contribute to develop a new paradigm in designing and operating these reactors.

The project has been supported by Swedish Energy Agency, Norrbotten Research Council, and Swedish Centre for Biomass Gasification.

Publications

• Marcelo Dal Belo Takehara, Kentaro Umeki, Rikard Gebart, Investigation of oxygen-enriched biomass flames in a lab-scale entrained flow reactor, Fuel 366 (2024) 131343. [link to the article (open access)] 

• Marcelo Dal Belo Takehara, Muhammad Aqib Chishty, Kentaro Umeki, Rikard Gebart, Pulverized biomass flame under imposed acoustic oscillations: flame morphology and emission characteristics, Fuel Processing Technology, 238 (2022) 107484. [link to the article (open access)] 

• Marcelo Dal Belo Takehara, Ángel David García Llamas; Muhammad Aqib Chishty, Kentaro Umeki, Rikard Gebart, Effect of acoustic perturbation on particle dispersion in a swirl-stabilized pulverized fuel burner: cold-flow conditions, Fuel Processing Technology 228 (2022) 107142 [link to the article (open access)]. 

• Ángel David Garcia Llamas, Ning Guo, Tian Li, Rikard Gebart, Kentaro Umeki, Rapid change of particle velocity due to volatile gas release during biomass devolatilization, Combustion and Flame 238 (2022) 111898 [link to the article (open access)]. 

• Qing He, Qinghua Guo, Kentaro Umeki, Lu Ding, Fuchen Wang, Guangsuo Yu, Soot formation during biomass gasification: A critical review, Renewable and Sustainable Energy Reviews 139 (2021) 110710. [link to the article] 

• Ángel David García Llamas, Ning Guo, Tian Li, Rikrad Gebart, Terese Løvås, Kentaro Umeki, Morphology and volume fraction of biomass particles in a jet flow during devolatilization, Fuel, 278 (2020) 118241. [link to the article] 

• Burak Göktepe, Kentaro Umeki, Ammar Hazim, T. Staffan Lundström, Rikard Gebart, Soot reduction in an entrained flow gasifier of biomass by active dispersion of fuel particles, Fuel 201 (2017) 111-117. [link to the article] 

• Ammar Hazim Saber, Burak Göktepe, Kentaro Umeki, T. Staffan Lundström, Rikard Gebart, Active fuel particles dispersion by synthetic jet in an entrained flow Gasifier: Cold flow, Powder Technology, 302 (2016) 275–282.

• Burak Göktepe, Kentaro Umeki, Rikard Gebart, Does distance among biomass particles affect soot formation in an entrained flow gasification process?, Fuel Processing Technology, 141 (2016) 99-105.