关键词: 沸腾床, 渣油, 加氢裂化, 结焦, 脱固油浆, 催化剂, 反应, 分馏

Abstract:

The article analyzes the reasons for easy coking and blocking in the ebullated-bed residue oil hydrocracking unit. The coking prone areas and typical symptoms of coking in an ebullated-bed residue oil hydrocracking unit of a refinery are introduced. In response to the problem, the optimization is carried out from feedstocks, catalysts, reaction and fractionation conditions and others. Through introducing the purified FCC slurry into the residue oil and dynamically adjusting the residue oil conversion rate to control coking: when processing the residue oil produced from Middle East high sulfur and low nitrogen crude oil, the conversion rate is controlled above 75%; when processing the residue oil produced from Middle East low sulfur crude oil, the conversion rate is controlled at no more than 70%; when processing the residue oil produced from low sulfur and high nitrogen crude oil, the conversion rate is controlled within 65%. The ratio of replacement is controlled at 0.90 to 0.95 kg of fresh catalyst per ton of residue; lower control liquid level(25%～30%) at the bottom of vacuum distillate tower, and increase the flow rate of distillate back to the bottom of the tower to reduce coking of asphalt on the bottom wall of the tower. And then, the sediment mass fraction of the bottom oil of the atmospheric tower is stable at less than 0.2%, ensuring the unit long-term stable operation under high residue oil conversion rate.

Key words: ebullated-bed, residue oil, hydrocracking, coking, purified FCC slurry, catalyst, reaction, fractionation