延迟焦化加热炉过剩空气量对其运行周期的影响

Effect of excess air on operating period of delayed coker heater

关键词:  热强度  过剩空气量  运行周期  延迟焦化  焦化加热炉 

Key words:  heat intensity  excess air  operating period  delayed coking  coker heater

摘要:

延迟焦化装置加热炉过剩空气量不仅影响其热效率,还影响加热炉的运行周期。介绍了加热炉炉管结焦机理,分析了影响加热炉炉管结焦的影响因素,利用专业的焦化加热炉工程设计软件,考察过剩空气量对焦化加热炉对流段和辐射段热负荷、炉管表面热强度、炉管管壁温度及火焰燃烧温度的影响,同时分析了对焦化加热炉炉管运行周期的影响。通过考察,某石化公司延迟焦化加热炉过剩空气量从5%(y)提高到13%(y),炉膛温度由715.8 ℃降至709.4 ℃,炉管管壁温度由510.3 ℃降至505.8 ℃。结果 表明:过剩空气量稍高可适当降低辐射炉炉管的表面热强度,从而降低辐射炉炉管的表面温度及辐射炉炉管内的结焦倾向,延长运行周期。 

Abstract:

Excess air in heaters of delayed coker unit will not only affect the thermal efficiency, but also affect the operating period of the heater. The coke deposition mechanisms of the heater tubes were briefly introduced, and the factors leading to tube coking were analyzed. Using the professional engineering design software, the influences of excess air on the heat duty of convective and radiant section of coker heater, the furnace tube surface heat intensity, the tube wall temperature and the flame temperature were discussed respectively. The influence on the operating period of the heater was analyzed simultaneously. When the excess air in the heater of a delayed coker unit was increased from 5% to 13%, the combustion chamber temperature might decrease from 715.8 ℃ to 709.4 ℃, the tube wall temperature might decrease from 510.3 ℃ to 505.8 ℃. The results showed that higher excess air could reduce the surface heat intensity of radiant tube, thus lowered the radiant tube surface temperature and tube coke deposition tendency, and extended the operating period of the heater as a result.