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U.S. Department of Energy
Office of Scientific and Technical Information

Materials and Manufacturing Challenges for Compact Heat Exchangers of Supercritical CO2 Power Cycles

Conference ·
OSTI ID:1571297
 [1];  [2];  [2];  [2];  [3];  [3];  [3]
  1. National Energy Technology Lab. (NETL), Albany, OR (United States); brian.fronk@oregonstate.edu
  2. National Energy Technology Lab. (NETL), Albany, OR (United States)
  3. Oregon State Univ., Corvallis, OR (United States)
The supercritical CO2 (sCO2) power cycles rely heavily on heat recuperation to increase efficiency. Compact heat exchangers are proposed to reduce equipment size and enhance heat transfer between heat source and sCO2. Microchannel architectures in these heat exchangers are typically formed by a lamination process wherein channels are formed in layers of sheet material, which are then stacked and joined together using diffusion bonding, brazing, or transient-liquid-phase bonding (TLPB). TLPB of Ni-based superalloy (Alloy 230) sheets into stacks was investigated. Electron microscopy identified solidification shrinkage porosity on the bond line as the most common defect in the TLP bonded stacks. Tensile yield strengths of 76-86 % of the base alloy strength were obtained on bonded stacks. Scanning electron microscopy on the fracture surfaces indicated ductile failure mode in the bonded zone. Environmental stability of joined regions in Alloy 230 stacks was investigated by exposing to CO2 at 700°C for 1500 hours. Mass change and post-exposure microscopic analysis showed a corrosion behavior similar to the base material.
Research Organization:
Oregon State University
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
DOE Contract Number:
EE0007108
OSTI ID:
1571297
Country of Publication:
United States
Language:
English