Analysis of the performance of vacuum columns of ELOU-AVT plants showed that in many cases long residue contains as much as 30 % vacuum gas oil with final boiling point up to 560°C. A comparative analysis was made of three options for increasing extraction of heavy gas oil in the residual fuel oil fractionation process. A conventional scheme involving pressure reduction at the vacuum column top, fractionation of the long residue without its heating after the primary vacuum column in an additional vacuum column, and fractionation of the residual fuel oil by a two-column scheme without heating of the residual fuel oil in the first column with extraction of only the light gas oil and with heating of the long residue of the first column, followed by its fractionation in the second column with extraction of the heavy vacuum gas oil was investigated. The performance of the vacuum column of the ELOU AVT-6 vacuum fractionation plant was analyzed. The process was simulated in Apen HYSYS environment. It is shown theoretically that extraction of heavy vacuum gas oil can be increased by deep-vacuum fractionation of vacuum residue. The merits and demerits of two-column vacuum fractionation of residual fuel oil were examined. A design of the fractionating column and feedstock feeding device is proposed.

ELOU-AVT 装置真空塔的性能分析表明，在许多情况下，长渣油含有多达 30% 的真空瓦斯油，终沸点高达 560°C。对比分析了在渣油分馏过程中增加重瓦斯油提取的三种方案。常规方案包括减压塔顶减压、在附加真空塔初级减压塔后分馏长渣油、不加热渣油通过两塔方案分馏渣油研究了第一塔中的油，仅提取轻质瓦斯油，加热第一塔的长渣油，然后在第二塔中分馏，提取重减压瓦斯油。分析了 ELOU AVT-6 真空分馏装置的真空塔的性能。该过程是在 Apen HYSYS 环境中模拟的。理论上表明，减压渣油的深减压分馏可以提高重减压瓦斯油的提取率。考察了渣油二塔减压分馏的优缺点。提出了分馏塔和进料装置的设计。