摘要 |
<p>A process for the neutralisation of an acid stream by (a) feeding the acid stream and calcium hydroxide through a first reaction zone, preferably a plug flow reactor (1) to a second reaction zone, preferably a stirred tank reactor (12) so that the calcium hydroxide partially neutralises the acid stream during feed of the stream to the second reaction zone, the second reaction zone being provided with means for measuring the pH of the solution within the second reaction zone (14) and means for feeding aqueous base to the second reaction zone. The apparatus comprises a plug flow reactor (1) provided with means for feeding the acid stream (4) and calcium hydroxide stream (8) thereto under ratio feed-forward control (7), and a stirred tank reactor (12) provided with means for measuring the pH of the solution therein (14), an aqueous base feed (15) and feedback control means (17) for controlling the addition of aqueous base thereto.</p> |