What are the main factors that affect the pressure drop in process piping systems?

I disagree. The higher the Reynolds number the lower the friction factor ... look at a Moody chart. Also the friction factor is dependant on the relative roughness of the pipe ... right hand axis of a moody chart High reynolds numbers donnot directly impact the pressure drop ... but high reynolds numbers usually happen at high velocities and high velocity causes high pressure drop

Another important consideration in fluid properties must be the presence of multiple phases in the flow media: vapor or entrained gas, or the presence of solids.

Pressure drop in a piping system is influenced by factors like pipe diameter, fluid velocity, pipe length, and fluid viscosity. Additionally, fittings, valves, and any obstacles in the pipe can contribute to pressure losses.

Process piping systems pressure reduction one of main issue is damaged pipes, leakages flanged connections along pipeline system. Another factor occurs process piping systems pressure sensors, probes, or other automatic gauging instruments inserted into the flow stream indicates error data to the pumping and level sensor system. Prevent from pressure drop issues on process piping systems, it is very important unchoke the pipes from any solid debris or obstructions that may cause bigger turbulence in the fluid flow. Routine maintenance should include checking for any structural problems with the piping system, besides damaged or worn sections of pipes must be replaced as soon as possible to avoid further more escalating loss factors.

Large pressure drop particularly changes in diameter from small to large diameter can cause Cavitation. This is a phenomenon in which the static pressure of a liquid reduces to below the liquid's vapour pressure, leading to the formation of small vapor-filled cavities in the liquid. Cavitation can cause vibration and mechanical degradation of the i piping.

Too add to this I would say change in diameter in a run of piping with constant feed flowrate/pressure. An opening from small to larger diameter would cause dramatic pressure drop and sometimes a change in phase of the material in the line.

The diameter of the pipe is a primary factor; smaller diameters increase frictional resistance and lead to higher pressure drops. The length of the pipe also contributes significantly, with longer pipes creating more surface area for friction, thus increasing pressure losses. Internal surface roughness is another important aspect, as rougher surfaces cause greater friction and turbulence, resulting in higher pressure drops. Additionally, the presence of fittings and valves, such as bends, elbows, tees, and control valves, introduces extra resistance and turbulence, further contributing to pressure drops.

The rule of thumb for sizing pipe for slurries is so the nominal & design flows are between 1 to 3 m/s of flow. Lower flows risked plugging. Higher flows will have wear issues.

In Bingham Plastics, there can be pressure drop even in cases of zero flow. This may be dependent on quiescent time. In fact, this is measurable and can be significant. As flow increases beyond this structure-breaking threshold, there is additional pressure drop which increases with flow.

The velocity of the fluid increases with higher flow rates, leading to greater frictional resistance and higher pressure drops. The flow regime, whether laminar or turbulent, is influenced by the flow rate; turbulent flow, which typically occurs at higher velocities, causes significantly higher pressure drops due to increased mixing and friction. In contrast, laminar flow, occurring at lower velocities, results in lower pressure drops. higher flow rates can also lead to increased energy consumption and wear on the piping system, making it essential to balance the flow rate for optimal performance and efficiency.

Nonographs are also a good starting point for flow / dP / velocity / diameter. One has to remember as well all these equations are derived from experiments..........pressure drop is often presented as an exact science yet there is plenty of variance in the data (1930s-1960s) used to derive Colebrook, Cranes formulas, Darcey-Weisbach and yet it is reported on graphs with no accuracy / repeatability / variance data. A great mentor of mine once said these methods are 10 - 30% accurate IF USED IN CONTEXT. I think the best I have ever had in 30 years design / ops is 6% accuracy, strangely with multiphase pressure drop (you'd have thought the least accurate) using the Rose-Duckworth methods.

Typically, the pipe smooth ie: stainless steel vs carbon steel that with most liquids water and it’s corrosive nature creates friction and thus pressure drop, simple! Also are the # of 90s, types of valves, and as mentioned pipe size changes, and the vertical height the liquid changes, if any.

A common mistake is estimating pressure drop based on the pipe lengths and ignoring the elbows, valves and other hardware. In reality, the pressure drop through relatively short straight sections of pipe is low compared to the pressure drop going through strainers, elbows and valves.

Pressure drop calculation highly depends on the flow regime. There are many methods available but for example, for multiphase flow in a pipeline, the pressure drop calculations become more complicated, and not only do the properties of each phase require attention but also the interactions between the phases have great importance. To select a proper method, a very good understanding of the fluids, the phases, flow regimes, etc is needed. In Multiphase flow, more complicated experimental correlations have to be employed. This is incorporated in a few software e.g., Olga is one of the best software that provides rich correlations for multiphase flow in a pipeline.

Most software has the Colebrook-White mathematical representation for the Moody diagram. However, other simpler equations are available. Be sure to be careful whether you are using the Moody friction factor or the Fanning friction factor. They differ by a factor of 4. Pressure drop equations and calculators can be found at https://www.LMNOeng.com

Just curious if process engineers still calculate pressure drop in equivalent pipe lengths? Used to commonly do this when calculating pressure drop in a Coriolis meter.

Just a gentle bump for energy consumption/ carbon emissions: going up a pipe size can significantly reduce pressure loss and therefore pump power. So you're up against the age old CAPEX Vs OPEX. But with Net Zero approaching perhaps we can add more weight to the OPEX argument.

Here’s something that I’ve seen time to time: - garbage bags clogging up control valves - hard hats - coveralls - and probably anything else you can’t even imagine right now

All else considered, the main factor influencing pressure drop in a process piping system is money, the more money you have the lower pressure drop you can afford.

Absolutely! When it comes to critical systems (PSV lines, Pump/compressor systems, etc) where phase and properties are predetermined for equipment design, we use equivalent lengths. Grab isometric drawings and get elevations, lengths, elbows and elbow types, valve and valve types (cranes predetermined drops) and plug our way pretty quickly and thoroughly through a system.