Abstract:

The 1.2 MM TPY heavy oil FCC unit of PetroChina Lanzhou Petrochemical Company has experienced an increase in SO_x content in the regenerated flue gas due to changes in feedstock properties, and the problem of blue smoke tailing in the discharged flue gas has become increasingly serious. In order to improve the appearance of smoke plumes, avoid excessive TDS(total dissolved solid) in discharged wastewater, and reduce the operating load of wet flue gas desulfurization tower, industrial experiments are conducted using enhanced RFS09 sulfur transfer agent and optimizing unit operation to eliminate blue smoke tailing in discharged flue gas. The results show that when the sulfur mass fraction of the feedstock is 0.4%～0.7%, and the sulfur transfer agent dosage accounts for 3.5% of the catalyst system storage, the phenomenon of blue smoke tailing can be controlled; the SO₂ in the flue gas at the inlet of the desulfurization tower is stably controlled below 500 mg/m³, the alkali consumption is reduced by 48.5%, and the TDS of the discharged wastewater is reduced from 41,400 mg/L to 6,400 mg/L, the COD(chemical oxygen demand) of the wastewater is improved, and the sulfur in the flue gas is significantly transferred to the gas product. The application of enhanced RFS09 sulfur transfer agent has no negative impact on product distribution, product properties and unit operation. This industrial experiment further demonstrates that the enhanced RFS09 sulfur transfer agent can effectively reduce the source emissions of FCC regenerated flue gas pollutants and reduce secondary pollution.

Key words: sulfur transfer agent, RFS09, FCC flue gas, blue smoke trailing, SO₃, alkali consumption, TDS, COD

摘要：

中国石油天然气股份有限公司兰州石化分公司1.2 Mt/a重油催化裂化装置因原料性质变化导致再生烟气中SO_x含量上升，外排烟气蓝烟拖尾现象愈发严重。为改善烟羽外观、避免外排废水TDS(溶解性固体总量)超标并降低湿法脱硫塔操作负荷，开展了运用增强型RFS09硫转移剂并优化装置操作、消除外排烟气蓝烟拖尾的工业试验。结果表明：当原料硫质量分数为0.4%～0.7%、硫转移剂藏量占系统藏量的3.5%时，蓝烟拖尾现象得以控制，脱硫塔入口烟气SO₂的质量浓度稳定控制在500 mg/m³以下、碱液消耗量降低48.5%、外排废水TDS由41 400 mg/L降至6 400 mg/L,废水COD(化学需氧量)减小，烟气中的硫大幅向气体产品中转移。增强型RFS09硫转移剂的应用对产物分布、产品性质和装置运行均无负面影响。该工业试验也进一步表明：增强型RFS09硫转移剂能很好地实现催化裂化再生烟气污染物源头减排，并减少二次污染。

关键词: 硫转移剂, RFS09, 催化裂化烟气, 蓝烟拖尾, SO₃, 碱液消耗, TDS, COD