In this paper,main equipment and processes for producing small tonnage tar products are introduced.Optimization is given by adding liquid seal and flow control device on side-cut line of the negative pressure intermittent distillation column so that actual process requirement can be met,economic benefit can be maximized and full play can be given to the advantages of small tonnage products,with annual economic benefit of 1 million yuan.

Negative pressure distillation, Low capacity tar products, Liquid sealing device; Improvement method of distillation unit, Flow control device