I’m seeking help from fellow colleagues regarding the purging issues that occur during the first operation of acid water stripping and solvent regeneration! ! ! !
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This post was last edited by liaifeng on 2018-8-1 at 10:57. For the first operation of distillation and regeneration, procedures such as purging, pressure testing, airtightness checking, and water washing are required. Questions: 1. Is steam or air used as the purging medium? If steam is used for purging, are the thermal stresses on the pipes taken into account? Apart from water hammer, could thermal damage be caused to the pipes? ； Additionally, it should be determined whether steam purging enters the tank or the solvent container; if it does, whether the anti-corrosion coating on the tank might peel off due to the high temperatures. After all, the operating temperatures for acid water tanks and solvent containers are only 60-70 degrees. 2. What medium is used for pressure testing? After checking relevant information, it was found that many suggestions recommend using water for pressure testing. Please briefly describe the advantages and disadvantages of pressure testing various types of media! 3. Which order is more reasonable for the processes of purging, pressure testing, airtightness testing, and water washing? I hope all fellow sailors will engage in more discussions to establish a more reasonable startup procedure for the sulfur combined facility! Please have the forum owner pin this post so it’s easier for everyone to discuss and learn! Thank you!
So many views, and not a single answer
No one answered, so let me explain. I have only been working for half a year since graduating, so there might be mistakes in what I say; please correct me, and let’s all learn together*: 1. Steam purging. The impact of thermal stress should be minimal; according to the experienced workers, steam was used for fuel gas displacement back in the day, as it has great power. Pipes should be fine at temperatures below around 300 degrees, as long as steam is applied for a short period of time. For steam to enter the large tank, I don’t think it’s necessary; washing with water is sufficient. On the contrary, I believe it is necessary to purge the tank with steam before carrying out maintenance work inside it; (however, one must take into account the possibility of a sharp increase in tank pressure, and high temperatures may cause oil in the tank walls to vaporize). The steam purging required for a tank being put into use for the first time is not as critical as the purging done during maintenance. I can’t explain why it’s possible to use steam purging even at a low design temperature; however, heat exchangers with design temperatures in the tens of degrees can also be purged using steam, provided that the vent on the other side is opened. I am not aware of the temperature tolerance for corrosion resistance. 2. The system can be pressurized using nitrogen, with the pressure applied usually being higher than the operating pressure. According to the information, hydrotesting likely refers to the pressure testing of equipment; water is commonly used for this purpose, as it provides a higher level of safety in case the equipment fails under pressure and bursts. Water is relatively incompressible, while some materials that cannot be exposed to water can be tested using gas instead. Nitrogen can be used for system pressure testing. 3. The order of these steps – washing, purging, pressure testing, and airtightness check – might be incorrect in many ways; I hope everyone can help me correct it. I’m a newcomer who hasn’t even turned a valve yet during my practical training phase, half a year after graduating
Steam purging must pass over the pump; steam must not enter the pump