Sasakura Engineering Co., Ltd.

Asahi Glass Company, Limited

Shiro Ohno

Hiroki Kamiya

Hiroshi Funaki

Koichi Yanase

Yasushi Nishimura

Mikio Morita

Masao Uehara

Norio Shintani

Kenichiro Nagatomo

Nobuyuki Deguchi

Satoru Hirano

An aqueous solution containing a fluorine-containing emulsifier in a low concentration of at least 1 ppm by mass and at most 1% by mass (e.g., coagulation waste water after an emulsion polymerization of a fluoropolymer and/or an aqueous solution obtained by washing with an aqueous solution a waste gas from a drying process and/or a heat treating process of the fluoropolymer) is subjected to vacuum concentration under a pressure of at most 100 kPa and a temperature of the aqueous solution of at most 100&#xb0; C. by means of a heating tube surface evaporation type concentrator equipped with a heat pump or the like, and the fluorine-containing emulsifier is recovered from a highly concentrated aqueous solution containing the fluorine-containing emulsifier in a higher concentration of at least 5% by mass. According to the present method, the fluorine-containing emulsifier can be recovered with a high yield from a low-concentration liquid such as coagulation waste water of a fluoropolymer.

Method for recovering fluorine-containing emulsifier

This disclosure relates to a centrifugal separator for separating suspended substances from a liquid such as the waste water of a ship. The centrifugal separator comprises a base frame, a tubular drive shaft journalled vertically on the frame and adapted to be driven, a cylindrical rotor fixed coaxially to the shaft adjacent one end thereof, a circumferential chamber formed inside the rotor around the shaft and the chamber having upper and lower ports adjacent the shaft, a pipe fixed coaxially inside the shaft, an inner passage formed inside the pipe, an annular passage formed inside the shaft and around the pipe, each of the passages communicating with one of the ports, axially aligned first and second headers formed on the frame, each of the headers having a port, the other end of the shaft extending rotatably into the first header so that annular passage opens in the first header, and one end of the pipe extends rotatably through the first header and into the second header so that the inner passage opens in the second header. The circumferential chamber is formed by an outer cylindrical wall and an inner conical wall, the diameter of the conical wall increasing in the downward direction.

Centrifugal separator for separating sludge in waste water

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Osaka, Japan

Shiro Ohno