Abstract: Taking the atmospheric tower of a ten million ton refinery as the research object, the influence of extraction position of the middle section of the atmospheric tower on the heat exchange network is investigated by using PRO Ⅱ process simulation software and i-HEAT heat exchange network calculation software. The results show that when the second middle extraction/return position of atmospheric tower moves down to the same position of the third side line. The temperature of heat extraction can be increased by 12 ℃, the heat extraction can be increased by 9.3 MW, the final temperature of heat exchange by the economic pinch temperature difference can be increased by 1.2 ℃, the heat load of the heating furnace and cooling water consumption are reduced by 0.9 MW and 0.5 MW respectively. The temperature of the surplus heat below the pinch point increases correspondingly. The original surplus heat can produce 11.7 MW medium-pressure steam and 4.4 MW low temperature hot water. After the scheme adjustment, the surplus heat can produce 10.6 MW high-pressure steam and 5.6 MW medium-pressure steam. The steam output and pressure increase obviously and the economic benefit is remarkable. Especially for refineries with insufficient high-pressure steam, moving down second middle extraction/return position of atmospheric tower represents a significant advantage.

Key words: atmospheric tower, extraction position, heat extraction, heat exchanger network, final temperature of heat exchange

摘要： 以某千万吨级炼油厂的常压塔为研究对象,使用PRO Ⅱ和i-HEAT软件,考察常压塔中段抽出位置对换热网络的影响。结果表明:常二中的抽出/返回位置下移至与常三线相同的抽出位置时,取热温度提高了12 ℃,取热量增加了9.3 MW,经济夹点温差下的换热终温升高了1.2 ℃,加热炉热负荷降低了0.9 MW,冷却水消耗降低了0.5 MW。原富余热量可产中压蒸汽11.7 MW、低温热水4.4 MW,方案调整后,富余热量可产高压蒸汽10.6 MW、中压蒸汽5.6 MW,产汽量明显增加,经济效益显著。对于高压蒸汽供给不足的炼油厂,常二中抽出/返回位置下移方案的优势更为明显。

关键词: 常压塔, 抽出位置, 取热量, 换热网络, 换热终温