Yubo Qin Description of Dagang Decompression Tower
PetroChina Dagang Petrochemical Company
5 Mt/a atmospheric and vacuum distillation unit
Vacuum tower (C-1201)
Tower internals design and manufacturing
1. Transformation background
In 2004, the internal parts and packings of vaccum tower (C-1201) in Dagang Petrochemical were designed and manufactured by Tianjiu Company. After the device was started, the tower internalts and the packings were severely corroded, and the air cooling at the top of the tower was corroded. The device could not operate for a long period. Since then, Tianjiu Company, Zehua Company, Sulzer Company, etc., have carried out many transformations, replacing the packings in the decompression tower for 6 times, and carrying out two major technical transformations. After the above transformation, the long-term operation of the device was still not achieved. In a relatively short period of time, serious corrosion phenomena have occurred, seriously affecting the normal operation and safe production of the device.
In May 2014, the decompression tower was reformed by Pei-yang National Distillation Technology Corporation Limited (Pei-yang Distillation) during maintenance. In the case of short reconstruction period and difficult reconstruction, most of the internal parts and packings in the middle section and the washing section of the second reduction section were updated through process and structure optimization, thickness optimization, and material upgrade. After the transformation of the device, the start-up is successful, and the technological indexes meet the design requirements. Up to now, it has been running steadily for 2 years and 1 month, and no internal parts or packings corrosion has affected the device operation. Through the transformation of the vacuum tower by Pei-yang Distillation, the longest stable operation time of the device was achieved.
In order to completely solve the corrosion problem and meet the long-term normal production needs of the device, a major renovation of the decompression tower was required.
2. Transformation plan
The atmospheric and vacuum distillation unit of Dagang Petrochemical Company processes low sulfur and high acid crude oil. The vacuum tower is of fuel type and adopts full packing dry operation. The original diameter of the tower is Φ5200 / Φ7400 /Φ8200 /Φ4200mm. Due to the long-term severe corrosion of vacuum tower, three-line segment and the washing section and internal parts, the vacuum tower, three- line segments and washing tower body and internal parts will be partially replaced and transformed, and the tower diameter of replacement section will be expanded from Φ8200mm to Φ9800mm.
At the same time, the material was upgraded. The material of the composite layer of the new tower was upgraded to 625 alloy, and the material of the internal parts and packings of the new tower was upgraded to AL-6XN.
The diameter of the vacuum tower after transformation is Φ5200 / Φ7400 / Φ9800 / Φ8200 /Φ4200mm. The packing type of the modified part is selected according to the different gas-liquid load conditions of each section.
The tower body and internal parts minus the second line section and above, the feed section, and the section below the feed section are considered according to profit. A number of patented technologies and proprietary technologies for packings and tower internals developed by Tianjin University and Pei-yang Distillation have been applied to the internal heat exchanger section of the first and second heat exchange sections, and the washing section. The basic structures such as and distributors in this project have been successfully applied to the design of many related plant construction and renovation projects undertaken by Pei-yang Distillation.
5 Mt/a atmospheric and vacuum distillation unit
Vacuum tower (C-1201)
Tower internals design and manufacturing
1. Transformation background
In 2004, the internal parts and packings of vaccum tower (C-1201) in Dagang Petrochemical were designed and manufactured by Tianjiu Company. After the device was started, the tower internalts and the packings were severely corroded, and the air cooling at the top of the tower was corroded. The device could not operate for a long period. Since then, Tianjiu Company, Zehua Company, Sulzer Company, etc., have carried out many transformations, replacing the packings in the decompression tower for 6 times, and carrying out two major technical transformations. After the above transformation, the long-term operation of the device was still not achieved. In a relatively short period of time, serious corrosion phenomena have occurred, seriously affecting the normal operation and safe production of the device.
In May 2014, the decompression tower was reformed by Pei-yang National Distillation Technology Corporation Limited (Pei-yang Distillation) during maintenance. In the case of short reconstruction period and difficult reconstruction, most of the internal parts and packings in the middle section and the washing section of the second reduction section were updated through process and structure optimization, thickness optimization, and material upgrade. After the transformation of the device, the start-up is successful, and the technological indexes meet the design requirements. Up to now, it has been running steadily for 2 years and 1 month, and no internal parts or packings corrosion has affected the device operation. Through the transformation of the vacuum tower by Pei-yang Distillation, the longest stable operation time of the device was achieved.
In order to completely solve the corrosion problem and meet the long-term normal production needs of the device, a major renovation of the decompression tower was required.
2. Transformation plan
The atmospheric and vacuum distillation unit of Dagang Petrochemical Company processes low sulfur and high acid crude oil. The vacuum tower is of fuel type and adopts full packing dry operation. The original diameter of the tower is Φ5200 / Φ7400 /Φ8200 /Φ4200mm. Due to the long-term severe corrosion of vacuum tower, three-line segment and the washing section and internal parts, the vacuum tower, three- line segments and washing tower body and internal parts will be partially replaced and transformed, and the tower diameter of replacement section will be expanded from Φ8200mm to Φ9800mm.
At the same time, the material was upgraded. The material of the composite layer of the new tower was upgraded to 625 alloy, and the material of the internal parts and packings of the new tower was upgraded to AL-6XN.
The diameter of the vacuum tower after transformation is Φ5200 / Φ7400 / Φ9800 / Φ8200 /Φ4200mm. The packing type of the modified part is selected according to the different gas-liquid load conditions of each section.
The tower body and internal parts minus the second line section and above, the feed section, and the section below the feed section are considered according to profit. A number of patented technologies and proprietary technologies for packings and tower internals developed by Tianjin University and Pei-yang Distillation have been applied to the internal heat exchanger section of the first and second heat exchange sections, and the washing section. The basic structures such as and distributors in this project have been successfully applied to the design of many related plant construction and renovation projects undertaken by Pei-yang Distillation.
