0
Research Papers

Fuel Cell Temperature Control With a Precombustor in SOFC Gas Turbine Hybrids During Load Changes

[+] Author and Article Information
Valentina Zaccaria

National Energy Technology Laboratory,
U.S. Department of Energy,
Morgantown, WV 26507
e-mail: Valentina.zaccaria@netl.doe.gov

Zachary Branum

The School of Engineering of
Matter, Transport, and Energy,
Arizona State University,
University Drive,
Tempe, AZ 85281
e-mail: Zachary.branum@gmail.com

David Tucker

National Energy Technology Laboratory,
U.S. Department of Energy,
Morgantown, WV 26507
e-mail: David.tucker@netl.doe.gov

1Corresponding author.

Manuscript received December 9, 2016; final manuscript received May 15, 2017; published online June 21, 2017. Assoc. Editor: Robert J. Braun.This work is in part a work of the U.S. Government. ASME disclaims all interest in the U.S. Government's contributions.

J. Electrochem. En. Conv. Stor. 14(3), 031006 (Jun 21, 2017) (8 pages) Paper No: JEECS-16-1159; doi: 10.1115/1.4036809 History: Received December 09, 2016; Revised May 15, 2017

Abstract

The use of high temperature fuel cells, such as solid oxide fuel cells (SOFCs), for power generation is considered a very efficient and clean solution for conservation of energy resources. When the SOFC is coupled with a gas turbine, the global system efficiency can go beyond 70% on natural gas lower heating value (LHV). However, durability of the ceramic material and system operability can be significantly penalized by thermal stresses due to temperature fluctuations and noneven temperature distributions. Thermal management of the cell during load following is therefore essential. The purpose of this work is to develop and test a precombustor model for real-time applications in hardware-based simulations, and to implement a control strategy to keep constant cathode inlet temperature during different operative conditions. The real-time model of the precombustor was incorporated into the existing SOFC model and tested in a hybrid system facility, where a physical gas turbine and hardware components were coupled with a cyber-physical fuel cell for flexible, accurate, and cost-reduced simulations. The control of the fuel flow to the precombustor was proven to be effective in maintaining a constant cathode inlet temperature during a step change in fuel cell load. With a 20 A load variation, the maximum temperature deviation from the nominal value was below 0.3% (3 K). Temperature gradients along the cell were maintained below 10 K/cm. An efficiency analysis was performed in order to evaluate the impact of the precombustor on the overall system efficiency.

<>

Figures

Fig. 1

HyPer facility layout

Fig. 2

Example of curve fitting approach for the integral term of Eq. (3)

Fig. 3

Cathode inlet temperature response after a step in precombustor fuel valve

Fig. 4

Step change in fc load and response of fuel utilization and heat production

Fig. 5

Thermal effluent, and turbine inlet and outlet temperatures trends after the step change

Fig. 6

Comparison between turbine outlet and cathode inlet temperature responses after the step change

Fig. 7

Temperature profile along the cell

Fig. 8

Temperature gradient distribution at different time

Fig. 9

Trends of fuel cell load, turbine outlet temperature, and precombustor flow over time

Fig. 10

Comparison between cathode inlet temperature trends in open and closed loops

Fig. 11

Trends of turbine inlet temperature and heat transferred to the turbine during time with temperature controller

Fig. 12

Temperature profile along the cell with temperature control

Fig. 13

Temperature gradient distribution at different time with temperature control

Fig. 14

System efficiency comparison with and without the use of precombustor for temperature control

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related Proceedings Articles
Related eBook Content
Topic Collections