The efficiency of generating electricity from heat using concentrated solar power plants (which use mirrors or lenses to concentrate sunlight in order to drive heat engines, usually involving turbines) may be appreciably increased by operating with higher turbine inlet temperatures, but this would require improved heat exchanger materials. By operating turbines with inlet temperatures above 1,023 kelvin using closed-cycle high-pressure supercritical carbon dioxide (sCO2) recompression cycles, instead of using conventional (such as subcritical steam Rankine) cycles with inlet temperatures below 823 kelvin1–3, the relative heat-to-electricity conversion efficiency may be increased by more than 20 per cent. The resulting reduction in the cost of dispatchable electricity from concentrated solar power plants (coupled with thermal energy storage4–6) would be an important step towards direct competition with fossil-fuel-based plants and a large reduction in greenhouse gas emissions7. However, the inlet temperatures of closed-cycle high-pressure sCO2 turbine systems are limited8 by the thermomechanical performance of the compact, metal-alloy-based, printed-circuit-type heat exchangers used to transfer heat to sCO2. Here we present a robust composite of ceramic (zirconium carbide, ZrC) and the refractory metal tungsten (W) for use in printed-circuit-type heat exchangers at temperatures above 1,023 kelvin9. This composite has attractive high-temperature thermal, mechanical and chemical properties and can be processed in a cost-effective manner. We fabricated ZrC/W-based heat exchanger plates with tunable channel patterns by the shape-and-size-preserving chemical conversion of porous tungsten carbide plates. The dense ZrC/W-based composites exhibited failure strengths of over 350 megapascals at 1,073 kelvin, and thermal conductivity values two to three times greater than those of iron- or nickel-based alloys at this temperature. Corrosion resistance to sCO2 at 1,023 kelvin and 20 megapascals was achieved10 by bonding a copper layer to the composite surface and adding 50 parts per million carbon monoxide to sCO2. Techno-economic analyses indicate that ZrC/W-based heat exchangers can strongly outperform nickel-superalloy-based printed-circuit heat exchangers at lower cost.A robust ceramic/refractory metal (ZrC/W)-based composite for use in heat exchangers in concentrated solar power plants above 1,023 kelvin is described, having attractive high-temperature thermal, mechanical and chemical properties combined with cost-effective processing.

中文翻译：

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用于聚光太阳能发电厂热交换器的陶瓷金属复合材料

使用集中式太阳能发电厂（使用镜子或透镜来聚集阳光以驱动热力发动机，通常涉及涡轮机）的热量发电效率可能会通过在更高的涡轮机入口温度下运行而显着提高，但这需要改善热量交换材料。通过使用闭式循环高压超临界二氧化碳 (sCO2) 再压缩循环，而不是使用入口温度低于 823 开尔文 1–3 的传统（例如亚临界蒸汽兰金）循环，在入口温度高于 1,023 开尔文的情况下运行涡轮机，相对热-电能转换效率可提高20%以上。由此产生的集中式太阳能发电厂（结合热能存储 4-6）可调度电力成本的降低将是朝着与化石燃料发电厂直接竞争和大幅减少温室气体排放迈出的重要一步。然而，闭式循环高压 sCO2 涡轮系统的入口温度受到用于将热量传递给 sCO2 的紧凑型金属合金基印刷电路型热交换器的热机械性能的限制。在这里，我们展示了一种坚固的陶瓷（碳化锆，ZrC）和难熔金属钨 (W) 复合材料，用于温度高于 1,023 开尔文的印刷电路型热交换器。这种复合材料具有吸引人的高温热、机械和化学性能，并且可以以具有成本效益的方式进行加工。我们通过多孔碳化钨板的形状和尺寸保持化学转化制造了具有可调通道模式的 ZrC/W 基换热器板。致密的 ZrC/W 基复合材料在 1,073 开尔文下的失效强度超过 350 兆帕，热导率值是该温度下铁基或镍基合金的两到三倍。在 1,023 开尔文和 20 兆帕的压力下，通过将铜层粘合到复合材料表面并向 sCO2 添加百万分之 50 的一氧化碳来实现对 sCO2 的耐腐蚀性。技术经济分析表明，基于 ZrC/W 的换热器可以以更低的成本大大优于基于镍超合金的印刷电路换热器。