延迟焦化装置大油气管线结焦原因分析及改进措施

Analysis of coking on overhead vapor lines in delayed coking unit and solutions

某1.0 Mt/a延迟焦化装置焦炭塔顶大油气管线原设计为90°弯头形式,急冷油注入采用传统三点斜插式,在装置运行过程中发现大油气管线结焦速度较快,在3个月内,焦炭塔顶压力由0.17 MPa增加至0.28 MPa,影响装置的安全生产及经济效益。为解决上述问题,对大油气管线形式及急冷油注入方式进行改造:将焦炭塔顶大油气管线形式由90°弯头改为可在线清焦的四通结构,同时将急冷油注入方式由三点斜插式改为喷嘴结构,并对急冷油的注入位置、消泡剂的注入方式及工艺操作参数进行了优化。装置改造后大油气管线的清焦周期延长至6个月,且能够实现在线清焦,实现了安全生产及提高经济效益的综合效果。

The 90 degrees bend was originally designed for the overhead oil vapor lines of a 1. 0 MM TPY delayed coking unit,and traditional three point oblique insertion was adopted for the injection of quench oil.The rapid coking was found in the oil vapor line,Within three months,severe coking was found on the surface of overhead vapor lines,and the pressure of the coke drum overhead was increased from 0. 17 MPa to 0. 27 MPa,and economic benefit and safe operation of the unit were affected. To solve these problems,the form of overhead vapor lines was modified and injection of quench oil was revamped： the form of overhead vapor lines was revamped from 90 degrees bend to four way structure and the injection of quench oil was modified from three point oblique to nozzle structure. In addition,the injection point of quench oil,injection mode of foam removal agent and process parameters were also optimized. After revamping,the coke cleaning cycle of overhead vapor lines was extended to6 months and online coke cleaning was realized. Safe operation and good economic benefits have been achieved.