单项选择题
A.二萃进料大B.一萃塔釜温低C.一萃塔溶剂小D.原料反丁烯高
A.溶剂回收塔B.炔烃精馏塔C.丁二烯精制塔D.炔烃萃取精馏塔
A.762~763B.772~773C.782~783D.792~793