The issue of steam flow rate
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This post was last edited by sxf1028102800 on 2016-2-25 09:29. I came across some information stating that the outlet temperature of the waste heat boiler is too high, exceeding the normal range; therefore, it is planned to reduce the boiler pressure in order to lower the outlet temperature. The pressure was reduced from 4 Mpa to 1 Mpa. The information also mentions the need to consider the steam flow rate and whether it can withstand the maximum pressure allowed by the pipes. I’m not quite sure what this means – could someone with expertise please explain it? Thank you, points will be given
Does the increase in flow rate resulting from steam pressure reduction require the “maximum pressure that the pipeline can withstand”? I really don’t understand this either. When discussing flow rates or selecting pipe diameters, factors such as pressure drop, sedimentation, erosion, wear, vibration, noise, static electricity, bubble point, and the critical velocity of gases are generally taken into account.
As I understand it, in the information provided, the phrase \"it is necessary to consider the steam flow rate and determine whether this flow rate can withstand the maximum pressure the pipeline can handle\" should have the word \"decrease\" added after \"pressure\". That is, “to consider whether the steam flow velocity can withstand the maximum pressure drop the pipeline can handle.” For saturated steam whose pressure is reduced from 4 Mpa to 1 Mpa, its temperature drops from 250°C to 180°C. With the amount of steam remaining unchanged, simple estimation using the ideal gas law indicates that its volume becomes 2.88 times the original volume; in existing pipelines, the flow velocity becomes 2.88 times the original value. The higher the flow rate, the greater the pressure drop. With the steam volume remaining constant, after a change in operating conditions, the pressure drop in the piping system increases, which may fail to meet the system’s process requirements. ”Maximum pressure the pipeline can withstand: it can handle 4 Mpa, and even more so at 1 Mpa. For reference
I find you guys a bit strange~~ First of all, do your subsequent processing steps have no requirements regarding pressure or temperature? Secondly, it is generally necessary to avoid excessive pressure drops and high flow velocities; the flow velocity of saturated steam should be kept between 25 and 40 m/s. Exceeding this limit can result in severe airflow noise as well as erosion. Lastly, why not consider solutions related to the boiler itself, such as reducing the heat load, thereby lowering the boiler pressure and outlet temperature? ~~
The pressure has dropped; pressure isn’t the issue – the problem is that the increased flow rate causes erosion
I think the same way; when the steam density decreases, the volumetric flow rate increases, which in turn raises the flow velocity. It is necessary to check the pressure drop in the pipeline to see whether the steam after pressure reduction at the user end can still meet the user’s requirements