Titanium does not show the required mechanical strength for high temperature high pressure applications and it can only be used to form liners for an SCWO apparatus. Therefore, pressure tubes made of alloy 625 were lined with titanium grade 2, Additionally corrosion tests with coupons made of titanium grades 2, 5, 7, 12 and P-C were performed.
Product Number:
51300-98417-SG
ISBN:
98417 1998 CP
Author:
N. Boukis, C. Friedrich, E. Dinjus
Publication Date:
1998
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According to literature data, Nickel base alloys are not sufficiently corrosion resistant in chloride bearing SCWO environments. Titanium was proposed several times as a suitable material for the construction of a corrosion resistant reactor. Titanium does not show the required mechanical strength for high temperature high pressure applications and it can only be used to form liners for an SCWO apparatus. Therefore, pressure tubes made of alloy 625 were lined with titanium grade 2, Additionally corrosion tests with coupons made of titanium grades 2, 5, 7, 12 and P-C were performed. The coupons were placed inside an alumina-lined reactor. Materials were exposed to simulated SCWO feeds consisting of water, oxygen and HCI, H2S0, or H,PO,. Experimental temperatures were up to 600°C, pressures up to 27 MPa and experimental times up to 200 hours. Corrosion in chloride containing solution is low. In the presence of sulfate or phosphate, corrosion of titanium grade 2 becomes severe. For these environments an upper limit of the corrosion rate could be estimated.Keywords: Titanium, oxidation, SCWO, supercritical, water, oxygen, hydrochloric acid, sulfiric acid, phosphoric acid, high temperature, high pressure