Shutdown and Startup of a SOFC/GT Hybrid System

Author(s):  
Christoph Stiller ◽  
Bjo̸rn Thorud ◽  
Olav Bolland

During shutdown and startup trips, the SOFC/GT hybrid system and its components must be protected from critical incidents such as anode oxygen exposure, excessive temperature gradients and carbon deposition. A further task is to minimise the need for auxiliary equipment and resources. The paper shortly presents a previously published detailed model of a pressurised SOFC hybrid cycle for the analysis of transients and control strategies. Shutdown and startup procedures are proposed based on the possibility to use the GT system for temperature control of the SOFC. Air flow and SOFC system inlet temperature are controlled by using a combustion device upstream the turbine, turbine exhaust gas throttling and a variable bypass around the recuperative heat exchanger. During startup, a small amount of hydrogen for the ignition phase of the SOFC is used. A considerable nitrogen demand for anode flushing has been detected, though it is uncertain how much is required to safely protect the anode from oxygen exposure. In the simulation, shutdown takes app. 2 hours and startup takes app. 5.5 hours. It is, however, uncertain how quick temperature variations the SOFC can withstand. A more flexible control strategy would allow the system to follow a low load immediately after startup initiation by utilizing the gas turbine.

Author(s):  
Ai-guo Liu ◽  
Yi-wu Weng

This paper presented the work on the design and part-load operation of a power generation system composed of a pressurized molten carbonate fuel cell and a micro-gas turbine (MCFC/MGT). The gas turbine was based on the commercially available one and the MCFC was assumed to be newly designed for the hybrid system. The effect of different control strategies on the performance of system during part-load operation has been analyzed. Performance of system and gas turbine was compared at the same part-load considering the different control strategies. The results show that the system efficiency is lower compared with the same systems analyzed by the other authors. The system has good performance when both the turbine inlet temperature and cell temperature are maintained close to the design-point condition, but it is difficult for gas turbine to obtain the original power.


2014 ◽  
Vol 977 ◽  
pp. 321-325
Author(s):  
Yuan Tao Sun ◽  
Jin Zhu Zhang ◽  
Yun Long Wang ◽  
De Hui Fan ◽  
Rong Fu Zhu

To study control strategies of combined hybrid electric vehicle, the paper does some working conditions Toyota Prius car such as starting, acceleration and uniform speed using testing instruments. The relation curves between speed of rotation, output moment of torque, speed of rotation of engine and time were obtained when power battery was in high SOC condition and low SOC condition about generator and electric motor. This relation curves can be useful to analyze control strategies of the combined hybrid system in some different conditions.


2000 ◽  
Author(s):  
M. Zahran ◽  
A. Hanafy ◽  
O. Mahgoub ◽  
M. Kamel

2020 ◽  
Author(s):  
Daniel Poremski ◽  
Sandra Henrietta Subner ◽  
Grace Lam Fong Kin ◽  
Raveen Dev Ram Dev ◽  
Mok Yee Ming ◽  
...  

The Institute of Mental Health in Singapore continues to attempt to prevent the introduction of COVID-19, despite community transmission. Essential services are maintained and quarantine measures are currently unnecessary. To help similar organizations, strategies are listed along three themes: sustaining essential services, preventing infection, and managing human and consumable resources.


1989 ◽  
Vol 24 (3) ◽  
pp. 463-477
Author(s):  
Stephen G. Nutt

Abstract Based on discussions in workshop sessions, several recurring themes became evident with respect to the optimization and control of petroleum refinery wastewater treatment systems to achieve effective removal of toxic contaminants. It was apparent that statistical process control (SPC) techniques are finding more widespread use and have been found to be effective. However, the implementation of real-time process control strategies in petroleum refinery wastewater treatment systems is in its infancy. Considerable effort will need to be expended to demonstrate the practicality of on-line sensors, and the utility of automated process control in petroleum refinery wastewater treatment systems. This paper provides a summary of the discussions held at the workshop.


Author(s):  
Ivan Herreros

This chapter discusses basic concepts from control theory and machine learning to facilitate a formal understanding of animal learning and motor control. It first distinguishes between feedback and feed-forward control strategies, and later introduces the classification of machine learning applications into supervised, unsupervised, and reinforcement learning problems. Next, it links these concepts with their counterparts in the domain of the psychology of animal learning, highlighting the analogies between supervised learning and classical conditioning, reinforcement learning and operant conditioning, and between unsupervised and perceptual learning. Additionally, it interprets innate and acquired actions from the standpoint of feedback vs anticipatory and adaptive control. Finally, it argues how this framework of translating knowledge between formal and biological disciplines can serve us to not only structure and advance our understanding of brain function but also enrich engineering solutions at the level of robot learning and control with insights coming from biology.


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