荷兰采购需求：耐高温窑具、辐射管和热交换器

We are developing a heat exchanger for cooling a challenging air-solids mix and need specific tubes. We're looking for 100 pieces, each 2m long with a 50mm ID and approx. 65mm OD. The preferred materials are reaction-bonded or sintered SiC, with density ≥ 3.0 g/cm³ and minimal free Si. Tubes must be suitable for abrasive gas-solid flows, with smooth internal surfaces and strict dimensional tolerances. They need to endure continuous operation at temperatures between 700 °C - 800 °C and tolerate thermal cycling with a gradient of at least 400 °C. Can you provide an estimate based on these specs?