(84b) Fractionation Towers Inspection From the Point of View of the Process

This paper was written to share experiences about fractionation towers inspection from the point of view of the process. The items mentioned are intended to provide guidance to the future towers inspectors to focus on points extremely important and relevant that will impact directly over the operation of distillation columns. A critical inspection is a tedious task. It is necessary to remain inside the tower for hours. However, it is a great opportunity to identify potential problems that could have the column when coming back into service. If we make a good job, we will save headaches when the tower is already in operation. The points mentioned in this paper correspond to inspections performed on Vacuum and Atmospheric fractionation towers, during routine maintenance shutdown of the units, on November 2008. The Refinery, called Luján de Cuyo(Belonging to YPF), is located in Argentina, in the province of Mendoza. Distilling vacuum tower, called CV10, is 37 meters length and a diameter of 8.2 meters in its largest section. It processes around 9000 m3/d of atmospheric residue. Distilling atmospheric tower, called CV1, is 39.6 m length and 4 m in diameter. It processes around 11000 m3/d of crude. Inspections for each of the towers had been previously planned to cover a total inspection. Previous planning is necessary to avoid delays and time extensions of the scheduled shutdown. Although was conducted a complete inspection of each one of the towers, the scope of this paper is only on the points of major interest, which will be useful for processes inspectors. We will focus on the following points: Vacuum tower: - Inspection and testing of distributors. - Inspection and testing of sumps and chimmey trays. - Inspection of Dual-element filter screens. - Design problems. Atmospheric distillation Tower: - Inspection of trays. (Valves, holes, measurements of weirs and clearance under the downcomer). - Inspection and testing of sumps. - Design problems. - Test of Gravity flow distributor.