关键词: 重交沥青装置, 减压塔, CTS技术, 高酸低硫原油, 抗腐蚀, 抗结焦, 填料腐蚀

Abstract:

The processing feedstocks for a 2.5 MM TPY heavy-traffic asphalt unit at a CNOOC refinery are mostly high acid and low sulfur cycloalkyl marine crude oil. Naphthenic acid can cause severe corrosion to the vacuum system under high temperature. Corrosion issues such as the third vacuum line filler and header tank of the unit are prominent, and there is coking phenomenon in the vacuum and high temperature section, which seriously affects the long-term operation of the unit. In order to solve the corrosion problem of the middle and lower fillers of the vacuum tower of the unit, the fillers are replaced with 317L and treated with stainless steel anti-corrosion and anti-coking surface modification technology(CTS), and long-term industrial application testing is conducted. After continuous operation for two years, the maximum and minimum tensile strength of 317L+CTS filler are 11.9% and 9.2% higher than 317L filler, respectively. After continuous operation for three years, there is no significant change in the tensile strength of 317L+CTS filler, and the tensile strength of 317L filler decreases by 16% to 41%. After being treated with CTS technology, the anti-corrosion, anti-coking, and anti-scaling of the filler have been significantly improved. The application of CTS technology in heavy-traffic asphalt unit can effectively reduce by high temperature naphthenic acid corrosion problem, extend the operating cycle, and ensure the safe, stable, and efficient operation of the unit.

Key words: heavy-traffic asphalt unit, vacuum tower, CTS technology, high acid and low sulfur crude oil, anti-corrosion, anti-coking, filler corrosion