Process Compressor Cleaning with Rochem: Case Study

We know our products work exceptionally well: we designed them that way. However, we don’t expect our customers to simply take our word for it. We carry out case studies, collecting the data which backs our claims.

Amongst other great benefits, Rochem equipment and FYREWASH® chemicals increase efficiency and reduce costs. This particular case study shines a light on the work we did for a UK customer, looking at the problems they had, what we supplied and the impact of our efforts.

The customer

This customer came to us from a cracked gas plant (oil refinery). They are the world’s largest producer of speciality graphite cokes and the largest anode coke producer in Europe.

Having noticed fouling, they were interested in upgrading their cleaning for their cracked gas compressor:

• Type: Centrifugal compressor, horizontally split, back-to-back arrangement
• Gas handled: Methane (CH4), Ethane (C2H6), Propane (C3H8), Hydrogen (H2)
• Sections: 2 (Low Pressure / High Pressure)
• Stages: 8 (4 x Low Pressure / 4 x High Pressure)

The issues

The customer experienced worsening fouling of the cracked gas compressor affecting both the LP and HP sections. Upon investigation, the main fouling component was ammonium chloride.

This increasingly problematic fouling caused reduced plant throughput and increased power consumption, i.e. reduced end product and higher costs. It also led to recurring unscheduled plant shutdowns in order to carry out urgent manual cleaning.

The existing cleaning schedule

When we were asked for help, the existing cleaning schedule involved a plant shutdown every five years to carry out manual cleaning of the process compressor internals.

The solution

It was clear to us and the customer that the existing cleaning schedule was insufficient to manage the levels of fouling experienced. We recommended introducing frequent on-line washing which is the preferred option for process compressors.

On-line washing is carried out during normal operation without impacting production. The cycle completes in a short timeframe while maintaining a level of cleanliness to facilitate effective, efficient compressor operation.

In this instance, we provided the following equipment:

• Nozzle assembly: LP and HP (nozzles to deliver a fine spray of water/detergent). We determined the optimum location for this specific customer’s nozzles using computational fluid dynamic modelling (CFD).
• Double block-and-bleed valve
• Hose assembly
• Wash delivery skid
• Full design study and calculations
• In-depth performance analysis

Due to the nature of fouling observed, we recommended using FYREWASH® F1 as the chemical of choice when washing. We offer a range of FYREWASH® chemicals suited to different situations. Our new FYREWASH Compresolve 5000 has been developed to target a wide range of foulants.

The results

We look at a broad spectrum of results to determine how effective a cleaning schedule has been. At this site the following data was recorded after implementing our recommended cleaning equipment and schedule:

• The polytropic head increased by 28%
• The pressure ratio improved from 2.0 to 2.5
• The polytropic efficiency improved from 62 to 82%
• The relative work input reduced
• The plant throughput increased by 10% (based on mass flow)

The customer has been extremely impressed with the upgraded system and we remain in contact to see if further improvements can be made e.g. to the cleaning schedule.

The bottom line: is process compressor cleaning worth it?

While process compressor cleanliness is our speciality, we are conscious that we work for businesses where the bottom line is… the bottom line. If our solutions are not cost-effective, customers will not be interested.

In this case study we looked to see if the numbers added up to make the results worth the investment and it is calculated that the customer will save USD 15M over two years! This is thanks to:

• Improved equipment reliability
• Increased plant throughput
• Reduced equipment maintenance/overhaul costs
• Less manhour costs
• Less unscheduled shutdowns (lasting an average 9-10 days each) i.e. profitable production is maintained

The initial expense of equipment, and ongoing cost of minimal maintenance and FYREWASH® chemicals is a tiny fraction of that huge saving. It’s undeniable that our work has been a huge success and we’re delighted to have another happy customer.

Get in touch

This case study is just one example of the great results we’ve achieved on behalf of our customers.

If you’re interested in how Rochem could help at your site, please get in touch. Our knowledgeable team will be happy to talk about your specific requirements and answer all your questions.

We offer bespoke cleaner solution based on detailed analysis of your fouling and process conditions to ensure maximum effectiveness from the cleaning process.