国内石化有机液体储罐VOCs深度减排管控技术进展

Recent advances of VOCs deep emission reduction and control technologies for petrochemical organic liquid storage tanks in domestic

石化是我国有机液体储存量最大的行业。有机液体储罐除大、小呼吸产气外,还有高温重油储存热裂解产气现象。现有国内外标准存在以下问题:(1)允许储罐排放的挥发性有机物(VOCs)浓度较高;(2)选用浮顶罐或固定顶罐+罐顶排气处理装置均符合标准,但允许排放的VOCs浓度差别很大。2019年,我国有机液体储存源VOCs排放量为392~904 kt,主要发生在石化行业。要提升我国环境空气质量、减少VOCs排放,储罐深度减排是关键。提出了“储罐VOCs深度减排”判据,将储存柴油的固定顶罐改为内浮顶罐可实现深度减排,现有固定顶罐、浮顶罐增加罐顶气治理可实现深度减排。介绍了中国石油化工股份有限公司大连(抚顺)石油化工研究院开发的以“低温柴油吸收-脱硫及总烃均化-蓄热氧化/催化氧化/热力焚烧炉”为核心的Tg系列储罐废气处理技术及应用实例,以及近年开发的内浮顶罐内置气袋VOCs减排技术。最后提出了储罐VOCs深度减排标准建议。

Petrochemical industry has the largest storage capacity of organic liquid in domestic. In addition to the gas emission by working and standing loss, the organic liquid storage tank also has the phenomenon of gas emission by thermal cracking during the storage of high-temperature heavy oil. There are two main problems in the existing domestic and foreign standards:(1)The concentration of VOCs allowed to be discharged from storage tanks is high;(2)The differences of emission reduction requirements are dramatic when applying floating roof tank or fixed roof tank+tank top exhaust treatment device. In 2019, VOCs emissions from organic liquid storage sources in domestic were 392~904 kilotons, mainly in the petrochemical industry. To improve our ambient air quality and reduce VOCs emission, deep emission reduction of storage tanks is the key. The criterion of “VOCs deep emission reduction for storage tanks” is proposed. Changing the fixed roof tank for storing diesel into the inner floating roof tank can be considered as deep emission reduction, and adding tank top gas treatment to the current fixed roof tank and floating roof tank can be considered as deep emission reduction. The Tg series storage tank waste gas treatment technology developed by FRIPP with “from low temperature diesel absorption to desulfurization and total hydrocarbon homogenization, then to regenerative oxidation or catalytic oxidation or thermal incinerator” as the core is introduced with examples of application, as well as the VOCs emission reduction technology with built-in air bag in inner floating roof tank developed in recent years. Suggestions on VOCs deep emission reduction standards for storage tanks are put forward.