Maximize Plant Throughput by Optimizing Wash Frequency

Fouling and scale buildup is the bane of any processing plant. It restricts capacity, reduces heat transfer, increases cleaning requirements, fuel consumption, and total costs.

In some high fouling industries pumps and pipelines can require cleaning and washing on extremely high frequencies, and the ability to identify when these become a ‘bottleneck’ can increase total plant throughput.

The type of equipment which can foul and require cleaning is vast, and can include anything and everything:

But how can you identify when a piece of equipment’s throughput or performance is degrading?

Every piece of equipment is different, but the key identifier is the same - historic key performance indicator degradation. The Key Performance Indicator (KPI) should be identified for every critical piece of equipment, but can be looked at for individual pipelines as well.

For example, take a heat exchanger with the purpose of recovering as much heat as possible (that is, it is not controlling to a set point):

In terms of fouling and wash requirements, the KPI would be total heat transfer (MW). If the heat transfer is continually reducing over time then the economic breakeven point can be used.

Another example is a simple pump. Looking at the pumping efficiency, or another common identifier is pumping throughput at maximum speed. If 6 months ago a pump was able to achieve 300 kL/hr at 100% speed, but is now only able to achieve 250 kL/hr, then the possibility of a wash should be considered (as well as pumping maintenance). This could be a result of solids buildup on either the pump suction or discharge or both. Looking at line pressures is often enough to identify the location of any restrictions.

Another tip to identify solid buildups within pipes where the fluid is hot is a thermal imaging camera - the buildup will act as an insulation and will result in a cold spot, further proof of washing requirements.

All different pieces of equipment have different KPIs which can be used to identify performance degradation. This degradation can then be tracked and measured to estimate the rate of scale build up, or fouling rate, leading to an improvement in planning and wash frequency.

“Success is simple. Do what’s right, the right way, at the right time”

Arnold Glasow

Washing frequency is often one of the simplest ways to maximize plant performance, throughput, and efficiency. The rule of thumb is to complete the wash before the restriction becomes a restriction.

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