Issues with the material of the propylene oxide storage tank shell
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Can a regular carbon steel Q235B be used for the tank body of propylene oxide storage tanks? Generally, stainless steel 304 is used, or the tank walls are lined with stainless steel. If an internal floating roof is used for the propylene oxide storage tank, can the design pressure be set at 2000–2500 Pa? Thank you!
Propylene oxide: Boiling point 34°C, fire hazard classification is Class A B. It can be stored at normal temperature under saturated pressure; a design pressure of no more than 0.5 MPa is sufficient. The material of choice is stainless steel 304, with carbon steel being an alternative as well.
Q235B can only be used at temperatures above 20°C; taking the influence of ambient temperature into account, Q345R should be chosen for carbon steel.
Propylene oxide: Boiling point 34°C; the explosive limit of its mixture with air is 2%–22%. The storage temperature should be kept below 25°C. In China, atmospheric pressure dome tanks are commonly used, equipped with breather valves; the positive pressure is controlled at 1.96 KPa. Depending on the operating temperature, a design positive pressure of 20 KPa and a negative pressure of 0.490 KPa can be adopted. As for the tank material, Q345R is preferred; its maximum operating temperature is 475°C and its minimum is -20°C.