Urgent~~~ Heating issue with the caustic soda tank
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Dear bosses, I work in the field of static equipment, and I’m currently facing a problem with a large liquid caustic tank. I would like to ask for your advice. Medium: 47% NaOH solution; operating temperature: 30°C. Tank material: S30408. The storage tank is equipped with an internal heating coil, with hot water as the medium flowing through this coil; the operating temperature for this coil is 70°C, and its material is also S30408. The operating pressure is 0.3 MPa. Is it okay to use this internal heating coil in this manner? I’ve checked some information, but the opinions vary.
No problem; it is used to prevent alkali crystallization in winter. The temperature inside the tube is designed to be 70 degrees, and the actual operating temperature will not be too high.
No problem; alkali solutions below 80°C do not cause significant corrosion to S30408
Corrosion of 304 by concentrated alkali at 80 degrees is still quite severe; it is recommended to use 316 or a higher-grade material instead.