Renewable Energy Global Innovations features: Co-Combustion Characteristics of Hydrothermally Treated Municipal Solid Waste with Coal in a Fluidized Bed

Significance Statement

Co-combustion of municipal solid biomass wastes and coal at high efficiency has been a challenge in recent time due to the hazardous nature of the waste gases generated in the process. Utilization of bubbling fluidized beds reactors, that use coal, has been called into question due these pollution effects. Measures have been taken to try and solve this problem that originates from the use of coal. In this paper, numerical and experimental models have been adopted for the simulation of the combustion process, within a bubbling fluidized bed reactor, so as to determine temperatures at which coal could be substituted with hydrothermally treated municipal solid waste.

A research team led by Professor Kunio Yoshikawa from Tokyo Institute of Technology and Associate Professor Tamer Ismail from Suez Canal University in Egypt, with Dr. Liang, Dr. Abd El-Salam and Prof. Yuqi Jin investigated the co-combustion characteristics of hydrothermally treated municipal solid waste with coal in a fluidized bed reactor. Their aim was to present models that use composite fuel (coal and municipal solid wastes) at least reactor modification. Their work is now published in the peer-reviewed journal Fuel Processing Technology.

Foremost, experiments had to be conducted using reliable CFD in order to predict crucial results and critical requirements for curbing and ensuring efficiency. The three approaches that were available for numerical simulations were: Euler-Lagrange approach, Euler-Euler approach and Discrete Element Method. Euler-Euler approach was adopted where ratios of 10, 20, 30 and 50% of the hydrothermally treated municipal solid waste were chosen to be tested at 700°C, 800 °C and 900 °C so as to determine the temperatures at which coal could be replaced with the hydrothermally treated municipal solid waste.

The research team had to determine the right temperature and mixture of the system that had the least emissions and yet could be operated at the least cost. They observed that for mixing ratios of 10 and 20% of the HT MSW there was a significant reduction in the CO outflow emission during the co-combustion with coal. Additional mixing of coal with the HT MSW lead to a further decrease in SO₂ emission from the combustion. Low levels of HCL were recorded for all the mixtures displaying a positive effect of the mixture. Nitrogen levels were also kept to a minimal as the blending mixing ratios of the HT MSW were increased.  Initially, high levels of NO were recorded due to increase in temperature but with the mixing of the HT MSW to 30% level, a significant drop was observed for all temperatures.

This research paper shows that with accurate simulation, trends for co-combustion can be predicted for various emitted gas species in the bed. This research sheds light into a promising way to simulate the combustion of solid waste in bubbling fluidized beds when using minimal coal. This study also reveals the features of a detailed structure for the combustion process inside the solid bed. Finally, it indicates the possibility of accepting the mixing ratio of the hydrothermally treated municipal solid waste, co-combusted with coal up to 30% without major modification of the coal-fired bubbling fluidized beds reactor.

About The Author

Dr. Tamer M. Ismail is an associate professor of Department of Energy and Fuel Science, Suez Canal University, Egypt. He obtained PhD in 2010, in Mathematical Modelling of MSW Incineration. He is one of the expert in the field of CFD of solid combustion and gasification having several research in this field. He is considered the pioneer in this field in Suez Canal University. He has a patent for CFD simulation code called, COMMENT- Code. Also, in the field of waste to energy he has several special work in designing many reactors, such as, fluidized bed, chemical looping combustor and bioreactor fermentor.

His major research areas are energy conversion, thermal engineering, combustion, gasification, waste treatment technologies, and he wrote many papers in this field. He works as research associate in Harbin Institute of Technology, Tokyo Institute of Technology and nstituto Politécnico de Portalegre, Universidade de Trás-os-Montes e Alto for combustion and gasification technologies.

About The Author

Dr. Kunio Yoshikawa is a professor of Department of Environmental Science and Technology, Tokyo Institute of Technology, Japan. He graduated from Tokyo Institute of Technology and obtained PhD in 1986. After graduation from Tokyo Institute of Technology, Prof. Yoshikawa worked for Mitsubishi Heavy Industries for one year, and then went back to his home university to become a research associate, associate professor and professor.

His major research areas are energy conversion, thermal engineering, combustion, gasification, waste treatment technologies and atmospheric environmental engineering, and he wrote more than 200 papers. He is an associate editor of Applied Energy. His main awards are AIAA (American Institute of Aeronautics and Astronautics) Best Paper Award in 1999, ASME (American Society of Mechanical Engineers) James Harry Potter Gold Medal in 2001, JSME (Japan Society of Mechanical Engineers) Environmental Technology Achievement Award in 2006, Fellow of JSME in 2008 and Best Educator Award of Tokyo Institute of Technology in 2014.

Reference

Liang Lu¹, T.M. Ismail², Yuqi Jin³, M. Abd El-Salam⁴, Kunio Yoshikawa¹. Numerical and experimental investigation on co-combustion characteristics of hydrothermally treated municipal solid waste with coal in a fluidized bed.  Fuel Processing Technology volume 154 (2016) pages 52–65.

Show Affiliations

1. Department of Environmental Science and Technology, Tokyo Institute of Technology, G5-8, 4259 Nagatsuta, Midori-Ku, Yokohama 226-8502, Japan
2. Department of Mechanical Engineering, Suez Canal University, Ismailia, Egypt
3. State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
4. Department of Basic Science, Cairo University, Giza, Egypt

 

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