Method for deodorizing and reducing grease hydrolysis rate by replacing part of water vapor with nitrogen

The invention discloses a method used for deodorizing with both nitrogen and water vapor, and more specifically relates to a method for deodorizing and reducing grease hydrolysis rate by replacing part of water vapor with nitrogen. According to the method, two-stage deodorization technology is adopted for deodorization of decolorized plant grease, and the hydrolysis rate of the grease is reduced by replacing a part of water vapor with the nitrogen for deodorization. According to a traditional deodorization process and a traditional two-stage deodorization process, steam is selected as steam stripping gas, certain oxygen is contained, hydrolysis and oxidization of grease may be caused, and the cost of adopted nitrogen is high. According to the method discloses in the invention, the two-stage deodorization process is adopted, grease is heated in an upper-stage packed tower under an extremely vacuum condition, and nitrogen is introduced into the tower and oxygen in the grease is discharged at a relatively low re