Analysis of a high-temperature heat exchanger for an externally-fired micro gas turbine. (22nd January 2015)

• Record Type: Journal Article
• Authors: Baina, Fabiola; Malmquist, Anders; Alejo, Lucio; Palm, Björn; Fransson, Torsten H.
• Is Part Of: Applied thermal engineering. Volume 75(2015:Jan.)
• Page Start: 410
• Page End: 420
• Publication Date: 2015-01-22
• Subjects: Externally fired gas turbine -- Heat exchanger -- Biomass gasification gas -- Deposit materials -- Effectiveness -- Pressure drop; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2014.10.014
• Languages: English
• ISSNs: 1359-4311

Abstract

Abstract: The externally-fired gas turbine (EFGT) can convert fuels such as coal, biomass, biomass gasification gas and solar energy into electricity and heat. The combination of this technology with biomass gasification gas represents an interesting option for gasification, for which it has been difficult to find a conversion technology. In this system, the heat exchanger deals with the contaminants of biomass derived gas instead of the turbine itself. However, these contaminants can build a deposit layer in the heat exchanger that can affect its performance. The heat exchanger is important in externally fired gas turbines since the turbine inlet temperature is directly dependent on its performance. Several studies on heat exchangers for externally fired gas turbines have been carried out. However, very few detailed studies were found comparing the performance of heat exchangers for externally fired gas turbines considering the effect of deposit materials on the surfaces. In this regard, this work compares the performance of a corrugated plate heat exchanger and a two-tube-passes shell and tube heat exchanger considering the effect of thickness of deposit material with different thermal conductivities on pressure drop and effectiveness. The results show that the effectiveness of the corrugated plate heat exchanger is more influenced at larger thicknesses of deposit materials than the two-tube-passes shell and tube heat exchanger. There is an exponential increase in the pressure drop of the plate heat exchanger while a monotonic increase of pressure drop is seen for the shell and tube heat exchanger. The increase in the thickness of the deposit material has two effects. On one hand, it increases the resistance to heat transfer and on the other hand, it reduces the through flow area increasing the velocity and hence the heat transfer coefficient. Additionally, the effectiveness of the heat exchangers had a stronger influence on the power output than the pressure drop. Highlights: The performances of two heat exchangers for externally fired gas turbine-cycles were compared. The effectiveness of the corrugated plate heat exchanger is more influenced at larger thicknesses of deposit materials. The effect of the deposit materials is twofold for both heat exchangers. The effectiveness has a stronger influence in the power output than the pressure drop.