| 摘要 |
A process and apparatus for producing sodium hydrosulfite by reacting a sodium borohydride/sodium hydroxide/water mixture with sulfur dioxide and sodium hydroxide and/or with sodium bisulfite, in a continuously circulating aqueous reaction mixture. Downstream of a point at which sodium hydrosulfite is drawn off the reaction mixture is divided into first and second streams 82, 84. Sulfur dioxide and sodium hydroxide and/or sodium bisulfite are fed with water into the first stream (82), the second stream (84) flowing through a bypass line and rejoining the first stream at a point (86) downstream of the input of these reactants. Further downstream the sodium borohydride mixture enters the system and the main reaction takes place in a static mixer (18) and a degassing tank (19).
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