Chiyoda Corporation

Takao Kameda

Sachio Asaoka

Hiroaki Nishijima

Nobuo Moriya

Kouji Sakashita

Nobuhiro Onda

Tetsuo Maejima

Noboru Takei

Makoto Yasui

Kazuya Kumagai

Masataka Uemura

Keiji Shimoda

Takeshi Kouzaki

Sosuke Kido

The impurity removal method removes impurities in an exhaust gas and includes forming a froth layer in a tank, by blowing the exhaust gas into an absorbing liquid contained in the tank via a gas dispersion pipe, wherein, given that a proportion of the gas occupying the froth layer is defined as a gas holdup, impurities such as soot dust included in a gas such as an exhaust gas is removed efficiently and at a low cost by setting a gas holdup in the froth layer to be 0.4&#x2dc;0.9, setting a height of the froth layer to be 0.2&#x2dc;1.8 m, and setting a gas-liquid contact area per unit volume of the froth layer to be 1500&#x2dc;2500 m/m.

Method of removing impurities

High purity, crystalline adduct of bisphenol A and phenol is produced multi-stage crystallization of a phenolic slurry of bisphenol A with a crystal separation and washing step being interposed between each of the two stages. Each of the crystallization stage includes a series of crystallization towers operated at decreasing temperatures. The crystallization of the slurry is performed by continuously discharging a portion of the slurry from each of the crystallization towers, introducing the discharged slurry into one or more coolers and then recycling the cooled slurry to the tower. Another portion of the slurry in each crystallization slurry is continuously discharged, heated for dissolving fine crystals of the adduct and then recycled to the crystallization tower so that large crystals are grown in each of the crystallization steps. An apparatus having a plurality of coolers and suitable for effecting the above crystallization is also disclosed.

Process for the production of crystalline adduct of bisphenol A and

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Yokohama, Japan

Takao Kameda