Problems with the calculation mode in Flarenet

The rating is calculated based on the input pipe diameter; it is used to evaluate the existing flare system design, as well as to design new flare systems. It helps identify the bottlenecks at various pipe diameters and determines the areas that need to be modified

Hello, I would like to ask further: (1) If my maximum allowable back pressure is 3.8 bar, and the valve outlet pressure reaches 4 bar according to the Rating mode. In other words, the pressure at the valve outlet is already greater than the maximum allowable back pressure; in such a case, will the safety valve not activate, resulting in pressure buildup inside the container? (2) Can this software determine whether the pressure in each pipe exceeds the pressure it can withstand?

This post was last edited by christopher on 2016-6-10 20:07. (1) Generally, the pressure at the outlet of a standard spring-loaded safety valve should not exceed 10% of the set value; if it does, the valve’s discharge performance is affected, which can lead to pressure buildup in the container. (2) The pressure that a pipe can withstand can be calculated based on its wall thickness, temperature, and allowable stress.

Hello, then I would like to ask further: I first used the Design pattern to design each pipe diameter based on the given discharge rate. If, in the currently designed torch piping system, the discharge volume increases due to complex fault conditions, and I use the Rating mode, it will show that the calculated back pressure is greater than the maximum allowable back pressure – I can understand this. But I really want to know what the consequences will be – will the safety valve not activate? So there’s no fluid in that torch pipeline system? You say that a container is overpressured yet the safety valve doesn’t activate – what kind of logic is that? I don’t quite understand. Also, if I increase the flow rate, can the pipeline withstand the pressure? Can this be determined using this software?

1. In Flarenet’s design for flare systems, it is possible to define multiple operating conditions; all of these conditions are taken into account, and the design algorithm determines the pipe diameter based on all of them. If changes occur in the leakage volume or leakage sources due to system modifications, the Debottlenecking approach can be used to identify the bottlenecks and determine which pipe diameters need to be enlarged or modified. 2. When the back pressure exceeds the maximum allowable value, it doesn’t mean that discharge is not possible; however, when the outlet of a conventional spring-loaded safety valve is under pressure equal to 10% above the set value, the valve’s discharge capacity drops sharply. If the discharge capacity does not meet the design value, it will cause overpressure in the container. Reference can be made to API 520, 521 3; as the discharge volume increases, flarenet can be used to determine the back pressure in the pipeline. As for whether the pipeline can withstand this pressure, it can be calculated by checking the wall thickness, temperature, and allowable stress. The flare can only determine the back pressure; it cannot verify whether the wall thickness meets the requirements. This is also simple – one just needs to calculate it using the formula for pipeline wall thickness. You can refer to API 14E

Are you still there, friend? You’re very proficient with this software; I’m still a bit confused. (1) According to the first point you mentioned, for example, if Condition 1 is a fire, Condition 2 is a power outage, and Condition 3 is cooling failure, each of these conditions has a different amount of leakage. I used Design to calculate the pipe diameter value for the most dangerous operating condition ； Or is it all operating conditions combined together to determine the diameter value for the maximum flow rate of each valve (with each valve possibly not being under the same operating conditions)? (2) What if one of my safety valves experiences a power outage or a fire at the same time? How should that be handled?

(1) In the Rating mode, when I viewed the pressure graph, I saw that the pipeline pressure after the safety valve showed a descending line graph. If it is evident that the starting pressure on this line graph is greater than the maximum allowable backpressure, the software will display a red color. Does this mean that the fluid is stuck in front of the safety valve, or does it mean something else? (2) In a flare system, what exactly do we mean by overpressure in such a system – is it the overpressure in the pipes within the flare piping network, or rather the overpressure in the pipes of the devices located before the valves? (3) In Flarenet, can the pressure that the pipeline can withstand be calculated based on the parameters required by the software? Is the allowable stress available in this software? Thank you so much!

1. The flarenet operating conditions are classified based on the source of release and the amount of release; it analyzes the source of release and the corresponding amount of release under different scenarios such as fires, power outages, and cooling failures. The pipe diameter calculated for the design conditions is the one that meets all conditions. 2, see Article 1.

1. A line graph showing a downward trend represents the pressure drop in the pipeline. If the software displays red, it means that the pressure in that section of the pipeline, as calculated, has exceeded the allowable backpressure. The amount of venting was entered by you in the FlareNet system; the software then gives a warning indicating that the pipe diameter is insufficient for such a level of venting. 2. We use FlareNet to analyze the flare system, starting from the release source and examining the pipelines downstream of it. 3. Flarenet cannot perform pressure and wall thickness calculations; the allowable pressure can be found by referring to tables based on the material.