What does the device purging plan include?

Purging medium, process, precautions, how to suppress pressure, how to handle instrument accessories, how to inspect, etc

When purging, be sure to remove the pressure gauge, flow meter, drain valve, temperature gauge, and control valve, or cover them with blind flanges

1. Purging process, steam inlet and exhaust points for each purging unit; 2. Whether various equipment and instruments need to be isolated, and the positions of the shut-offs; 3. Sequence of purging operations and control of purging time; 4. How to deal with various dead corners; 5. Safety precautions during purging, hazard identification, and corresponding risk mitigation measures

Here’s a table of contents for you. Table of Contents
Chapter 1: Preparatory Work Before Steam Purging and Pressure Testing 1-1
1.1. Purpose 1-1
1.2. Conditions 1-1
1.3. Preparation Work 1-1
1.4. Requirements for Pressure Testing 1-1
1.5. Precautions 1-2

Chapter 2: Operations for Steam Purging and Pressure Testing 2-1
2.1. Purging of the Main Process in the Plant’s Main Body 2-1
2.1.1. Purging of the Crude Oil Inlet Line 2-1
2.1.2. Purging of the Three Lines Before Crude Oil Treatment 2-1
2.1.3. Purging of the Three Lines After Crude Oil Treatment 2-3
2.1.4. Purging of the Tail Oil Process Line 2-4
2.1.5. Purging of the C-102 Bottom Pipeline 2-5

2.2. Purging of Various Side Lines in the Plant’s Main Body 2-7
2.2.1. Purging of the Initial Distillate System 2-7
2.2.2. Purging of the Initial Side Oil Line 2-8
2.2.3. Purging of the Normal Distillate System 2-8
2.2.4. Purging of the Normal Distillate Circulation Line 2-9
2.2.5. Purging of the First Normal Distillate Line 2-10
2.2.6. Purging of the Second Normal Distillate Line 2-11
2.2.7. Purging of the First Normal Distillate Line 2-12
2.2.8. Purging of the Second Normal Distillate Line 2-13
2.2.9. Purging of the Third Normal Distillate Line 2-14
2.2.10. Purging of the Reduced Distillate System 2-15
2.2.11. Purging of the Reduced Distillate Oil Line 2-16
2.2.12. Purging of the Internal Recirculation Line of the First Reduced Distillate Line 2-16
2.2.13. Purging of the First Reduced Distillate Line 2-17
2.2.14. Purging of the Reduced Distillate Circulation Recirculation Line 2-18
2.2.15. Purging of the Second Reduced Distillate Line 2-19
2.2.16. Purging of the First Reduced Distillate Line 2-20
2.2.17. Purging of the Third Reduced Distillate Line 2-21
2.2.18. Purging of the Second Reduced Distillate Line 2-22
2.2.19. Purging of the Fourth Reduced Distillate Line 2-23
2.2.20. Purging of the Washing Oil Line 2-25
2.2.21. Purging of the Fifth Reduced Distillate Line 2-25
2.2.22. Purging of the Vacuum Residue Oil Line 2-27
2.2.23. Purging of the Vacuum Bottom Quench Oil Line 2-29

2.3. Purging of the Light Hydrocarbons System 2-30
2.3.1. Purging of the Separator Tank at the Compressor Inlet 2-30
2.3.2. Purging of the Separator Tank at the Compressor Outlet 2-30
2.3.3. Purging of the Reflux Line at the Top of the Stabilization Tower 2-31
2.3.4. Purging of the Oil Drain Line from the Stabilization Tower 2-31
2.3.5. Purging of the Liquefied Gas Line 2-32
2.3.6. Purging of the Naphtha Line 2-33
2.3.7. Purging of the Non-condensable Gas Line 2-34
2.3.8. Purging of the Amine-Poor Liquid (MDEA) Line 2-35
2.3.9. Purging of the Amine-Rich Liquid (MDEA) Line (with Steam Sent Out of the Plant) 2-36

2.4. Purging of the Gas Systems 2-37
2.4.1. Purging of the High-Pressure Gas System 2-37
2.4.2. Purging of the Reduced Distillate Gas System 2-37
2.4.3. Purging of the Initial and Normal Distillate Gas Systems 2-38

2.5. Purging of Other Systems 2-40
2.5.1. Purging of the Sealing Oil System 2-40
2.5.2. Purging of the Heavy Dirty Oil System 2-41
2.5.3. Purging of the Startup Diesel System 2-41
2.5.4. Purging of the Startup Gasoline System 2-42
2.5.5. Purging of the Electrodesulfonation Oil Drain Line 2-43

2.6. Airtightness Testing of Towers 2-44
2.6.1. Airtightness Testing of the Initial Distillation Tower 2-44
2.6.2. Airtightness Testing of the Atmospheric Pressure Tower and Atmospheric Pressure Stripping Tower 2-45
2.6.3. Airtightness Testing of the Vacuum Distillation Tower 2-46
2.6.4. Airtightness Testing of the Stabilization Tower 2-47
2.6.5. Airtightness Testing of the Liquefied Gas Desulfurization Tower 2-48
2.6.6. Airtightness Testing of the Reduced Distillate Gas Desulfurization Tower 2-49

2.7. Appendix: Purging and Pressure Testing Procedures 2-50
2.7.1. Purging Procedures 2-50
2.7.2. Pressure Testing Procedures 2-55
2.7.3. List of Blind Flanges and Gaskets 2-59

Chapter 5 Pressure Testing of Equipment and Piping (Airtightness and Pressure Holding) 2 1 Airtightness Plan for System Equipment and Piping 2 1.1 System Airtightness Plan 2 1.1.1 Pressure Pipeline Pressure Testing Plan 2 1.1.2 Conditions to be Met Before Pressure Testing 2 1.1.3 Pressure Testing Equipment 2 1.1.4 System Airtightness Requirements 3 1.2 Pressure Testing 5 1.2.1 Pipeline Testing 5 1.2.2 Hydrostatic Testing 7 1.2.3 Pneumatic Testing 8 1.2.4 Leakage and Vacuum Testing 9 1.3 Cleaning Procedures 10 1.3.1 Pipeline Cleaning 10 1.3.2 Air Purging 11 1.3.3 Steam Purging 12 1.3.4 System Flushing 13 1.3.5 Chemical Cleaning 13 1.3.6 Pipeline Degreasing 14 1.3.7 Oil Cleaning 15 1.3.8 The methods for inspecting the quality of equipment degreasing and the corresponding acceptance criteria shall comply with the provisions below 15

It depends on what pipeline is being purged. If it’s a steam pipeline, it needs to be purged multiple times, with purging carried out several times a day; finally, it is determined whether it meets the standards based on the results of testing. The other pipelines can be purged with air, and one can feel whether they are satisfactory by hand.

Are there any relevant regulations that can be consulted?

Regarding the gas purging of the system before driving it for the first time: 1. Before purging the pipelines, the maintenance department removes all flow meters, filters, and other accessories from the pipelines； The control valve was removed, and the flow was directed through the bypass line. 2. The pressure should be increased slowly when gas is introduced into the tower to prevent the trays from being blown over. 3. During steam purging, steam must not pass through the pump body. 4. When purging cold exchange equipment (except reboilers), close the valves on its inlet and outlet pipelines, drain all the water remaining in the equipment, open the outlet valve and then slowly open the inlet valve to introduce steam; ensure that any water remaining in the equipment is continuously drained, and the vent valve must be kept open on the other side as well. 5. For the pipelines of the purging equipment, if there is no vent valve, open the flange on the side closest to the equipment to remove any debris from the pipelines; after that, tighten the flange and proceed with purging the equipment. 6. After purging each piece of equipment, the drain and vent valves should be fully opened to prevent a vacuum from forming in the system. 7. When purging each system is complete without any residues, maintain the pressure in all towers and containers at 0.6~0.7 MPa. 8. After the equipment pressure testing is completed, maintain the pressure for 2 hours before releasing it; someone should be assigned to monitor this process to prevent steam from condensing and creating a vacuum that could damage the equipment.

When it comes to environmental protection these days, purging must be done in a sealed environment

The steam pipeline purging plan of our unit is provided for reference only. “7.12 Pipeline Purging and Flushing 7.12.1 When each system is purged according to its pipe number, measures should be taken to prevent dirt from the pipelines from entering the equipment, or dirt from the equipment from entering the pipelines. 7.12.2 The system purging parameters shall meet the following requirements: 7.12.2.1 There shall be sufficient flow rate. 7.12.2.2 The purge pressure shall not exceed the design pressure. 7.12.2.3 The purging flow rate shall be no lower than the operating flow rate, and should not be less than 20 m/s. 7.12.3 Steam pipelines are purged using steam; when using steam for purging, the pipes should be heated gradually, and water should be drained promptly. After maintaining a constant temperature for a certain period of time, purging is carried out, followed by allowing the temperature to drop naturally to ambient levels. Then the temperature is raised again to heat the pipes, and purging is performed once more at that constant temperature. This process is repeated, generally at least three times. ”