3 replies to this topic

[Shaileshprocess]

For this project we have following problem statement, we are looking your expert opinion on feasibility on proposed solution.

 

 

Problem statement is as described below -  

 

Below is the requirement for flaring to existing acid gas flare in blocked discharge scenario .

 

 

• Single existing flare is not adequate to handle total relief rate during depressurization. Relief flow has to be routed to both existing flares.
• Above sketch shows 2 relief devices mounted on same line. Capacity for each relief valve shall be the same as respective flare capacity.
• It is essential that flow is distributed to each flare within their capacity. Therefore, conventional pop-action type relief device cannot be used, as they will give more than required flow which will exceed flare capacity.
• Therefore, modulating type relief devices (see excerpt below from API-520) have to be used in this application. Each pilot type relief valve shall be open at same set pressure and will release only required flow (110 TPH for one and 85 TPH for second).

 

Response on below clarifications is required from expert-

• Is it feasible to connect PSVs for different locations

Any past experience on similar system. 

Attached Files

•  PSV sketch.pdf   11.05KB   8 downloads

Edited by Shaileshprocess, 06 March 2023 - 11:22 PM.

[latexman]

I see no "Above sketch . . . " or "(see excerpt below from API-520)".  To add those, click Edit on original post (OP), click Use Full Editor, under the full editor text window you will see the Attach Files functions.

[Pilesar]

Maybe, but I think the solution as described is not feasible at first glance. Backpressures, springs, etc. will not be equal. As soon as one relief valve opens, it will stay open and rob flow from the other valve. Then they will fight each other. You will have full flow through the single valve alternately. In order to split the flow, you would then have to connect the flare headers downstream of a single relief valve. Then you would have two flares on a single header and risk backflow in the header which would be a safety problem. Instead, consider an instrumented protective system to open a vent to one flare header using an orifice plate for flow control. Then route the PSV discharge to the other header with setpoint at a higher pressure.

Edited by Pilesar, 06 March 2023 - 03:47 PM.

[Shaileshprocess]

sketch is added