Development of a Feedback Control System for a Lab-Scale Biomass Combustion System Using Programmable Logic Controller

Authors: Samuel O. Alamu, Seong W. Lee, Blaise Kalmia, Marc J. Louise Caballes, Xuejun Qian

Abstract:

The application of combustion technologies for thermal conversion of biomass and solid wastes to energy has been a major solution to the effective handling of wastes over a long period of time. Lab-scale biomass combustion systems have been observed to be economically viable and socially acceptable, but major concerns are the environmental impacts of the process and deviation of temperature distribution within the combustion chamber. Both high and low combustion chamber temperature may affect the overall combustion efficiency and gaseous emissions. Therefore, there is an urgent need to develop a control system which measures the deviations of chamber temperature from set target values, sends these deviations (which generates disturbances in the system) in the form of feedback signal (as input), and control operating conditions for correcting the errors. In this research study, major components of the feedback control system were determined, assembled, and tested. In addition, control algorithms were developed to actuate operating conditions (e.g., air velocity, fuel feeding rate) using ladder logic functions embedded in the Programmable Logic Controller (PLC). The developed control algorithm having chamber temperature as a feedback signal is integrated into the lab-scale swirling fluidized bed combustor (SFBC) to investigate the temperature distribution at different heights of the combustion chamber based on various operating conditions. The air blower rates and the fuel feeding rates obtained from automatic control operations were correlated with manual inputs. There was no observable difference in the correlated results, thus indicating that the written PLC program functions were adequate in designing the experimental study of the lab-scale SFBC. The experimental results were analyzed to study the effect of air velocity operating at 222-273 ft/min and fuel feeding rate of 60-90 rpm on the chamber temperature. The developed temperature-based feedback control system was shown to be adequate in controlling the airflow and the fuel feeding rate for the overall biomass combustion process as it helps to minimize the steady-state error.

Keywords: Air flow, biomass combustion, feedback control system, fuel feeding, ladder logic, programmable logic controller, temperature.

References:

[1] Fane, A. G., and C. Y. Wen. "Fluidized bed reactors." Handbook of multiphase systems (1982).
[2] Green Jr, L. "«They're off!» in the circulating FBC handicap." Coal mining (Chicago, Ill.) 22, no. 11 (1985): 49-52.
[3] McFarlane, Randall C., Terrence W. Hoffman, Paul A. Taylor, and John F. MacGregor. "Control of fluidized bed reactors. 1. Modeling, simulation, and single-loop control studies." Industrial & Engineering Chemistry Process Design and Development 22, no. 1 (1983): 22-31.
[4] Singh, Ravendra, Fernando J. Muzzio, Marianthi Ierapetritou, and Rohit Ramachandran. "A combined feed-forward/feed-back control system for a QbD-based continuous tablet manufacturing process." Processes 3, no. 2 (2015): 339-356.
[5] Haque, SK Hasan Hafizul, HM Imran Hassan, and SM Abul Hossain. "Comparison of Control System Using PLC & PID." In ASEE 2014 Zone I Conference. 2014.
[6] Beylot, Antoine, Jacques Villeneuve, and Gaël Bellenfant. "Life cycle assessment of landfill biogas management: sensitivity to diffuse and combustion air emissions." Waste management 33, no. 2 (2013): 401-411.
[7] Hiltunen, M., Nitrous oxide (N2O) emissions in fluidized bed boilers. Presentation in ECCP I Review: Non-CO2 Gases. Brussels, Belgium. http://forum.europa.eu.int/Public/irc/env/eccp_2/library?l=/eccp_fluorinated/presentations_meeting (referred 8.2.2006).
[8] Qian, Xuejun, Seong Lee, Raghul Chandrasekaran, Yulai Yang, Marc Caballes, Oludayo Alamu, and Guangming Chen. "Electricity Evaluation and Emission Characteristics of Poultry Litter Co-Combustion Process." Applied Sciences 9, no. 19 (2019): 4116.
[9] Zhu, S., and S. W. Lee. "Co-combustion performance of poultry wastes and natural gas in the advanced Swirling Fluidized Bed Combustor (SFBC)." Waste management 25, no. 5 (2005): 511-518.
[10] Griffen, Bryan T. "The design and evaluation of a PLC-based model predictive controller for application in industrial food processes." (2003).
[11] Petruzella, Frank D. Programmable logic controllers. Tata McGraw-Hill Education, 2005.
[12] Basu, Prabir. Biomass gasification and pyrolysis: practical design and theory. Academic press, 2010.
[13] Li, Pin-Wei, and Chien-Song Chyang. "A comprehensive study on NOx emission and fuel nitrogen conversion of solid biomass in bubbling fluidized beds under staged combustion." Journal of the Energy Institute 93, no. 1 (2020): 324-334.