Polyether polyol is abbreviated as polyether. It is an oligomer whose main chain contains ether bond (—R—O—R—) and the terminal group or side group contains more than 2 hydroxyl groups (—OH). It is prepared by addition polymerization of an initiator (a compound containing an active hydrogen group) with ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO), etc. in the presence of a catalyst. The largest polyether producers are all common polyether polyols. Polyether polyols are produced with glycerol (glycerol) as the initiator and epoxide, by changing the PO and EO addition methods (mixed addition or separate addition), addition ratio, addition order and other conditions. The main purpose 1. Detergent or defoamer L61, L64, F68 are used to prepare low-foam, high detergency synthetic detergent; L61 and L81 are used as defoamers in the papermaking or fermentation industry; F68 is used as an antifoaming agent in the blood circulation of artificial heart-lung machine to preven