Air separation unit operation guide

1.The cold box foundation is composed of foundation body, water baffle, cold insulation layer and surface layer. 2.The surface of fractionator foundation after completion shall meet the following requirements: a) There should be no cracks and other defects on the surface; b) The surface should be clean, and no inflammable materials such as wood board and linoleum are allowed to be carried; c) Surface flatness < 5 / 1000; d) The surface levelness is less than 5 / 1000, and the total length should not be more than 15mm. 3.After the foundation is qualified, mark the installation center line of the container according to the installation position of the vessel, and mark the direction and position of the pipe orifice.

Lean alloy steel is often used in special pressure-bearing equipment. The alloying elements often added include manganese, silicon, chromium, nickel, molybdenum, vanadium, boron and rare earth elements. Most of silicon and manganese melt into ferrite, only a small amount into cementite, which are commonly used strengthening elements in lean alloy steel. The amount of chromium and nickel is generally small, and the main role of chromium and nickel is to increase the undercooling degree of austenite and refine the microstructure. Part of chromium is dissolved in ferrite and some in cementite, which can improve the stability of cementite. Molybdenum is dissolved in ferrite slightly, and has the effect of solid solution strengthening. It is a strong carbide forming element, which can improve the high temperature strength of steel and improve the temper brittleness.