Case Studies

Analysis & Rerating Solve Pipeline’s Acoustic Resonance Problem

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The phenomenon occurs when a system experiences extreme vibration caused by excessive pump pressure and pulsation.

Written by: Greg Matteson & Jeff Johnson
Published by: Pumps & Systems

A North American natural gas liquids pipeline company was experiencing an acoustic resonance issue that cost up to $35,000 a month in maintenance and repair. A six-week project resulted in rerating three American Petroleum Institute (API) designation between-bearing (BB3) horizontal multistage split-case mainline pumps and performing extensive and specific vibration analyses to identify the problem. The project involved designing and manufacturing new impellers using exclusive milled vane technology, conducting API hydraulic performance tests, and returning the pumps into service.

This midcontinent pipeline gathers, processes, stores and transports natural gas—in this case, propane. Because of its geographic location, extreme temperatures and conditions are a factor in the selection of major equipment and components. The pumps operate at 2,917 gallons per minute with 2,926 feet at 1,500 horsepower and 3,560 revolutions per minute (rpm).

The Problem

The pipeline company was experiencing an acoustic resonance vibration problem at the pump crossover, causing major maintenance and repair issues. Acoustic resonance occurs when a system experiences extreme vibration due to excessive pump pressure and pulsation, with frequencies loud enough for humans to hear. This can happen with the use of variable speed drives.

The pulsations are caused by a non-uniform flow from turbulence, sudden change of flow structure, direction or cross-section.

The acoustic resonance had existed since the pumps were installed more than five years ago. Rather than repairing or replacing them, the company performed continuous unscheduled maintenance that cost as much as $35,000 in a single month.

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Engineering is at the Heart of Hydro Inc.’s Aftermarket Services

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Hydro Inc. has a strong engineering capability and an expansive global reach in the pump industry, especially in aftermarket services. Pump Engineer had the pleasure of speaking with George Harris, Chief Executive Officer and Founder of Hydro Inc., where he discussed the company’s recent research initiatives, reliability support for customers, customized designs and the significance of upgrades and health audits.

Written by: Deirdre Morgan
Publisher: Pump Engineer / December 2016

“We were very fortunate that early in the company’s development we had the good fortune to work closely with Dr. Elemer Makay, a foremost consultant to the power generation industry and a specialist in troubleshooting multi-stage, high energy pumps”, states Harris. “Engineering combined with meticulous observation and analysis in the field were key to his troubleshooting process. As a result of his training over a twenty year period, engineering became the focus and strength of Hydro Inc.’s aftermarket services”.

According to Hydraulic Institute statistics, 85% of the critical pumps in industries, such as power, refineries and pipelines, are custom designed for the specific application intended. In order to properly rebuild, upgrade or troubleshoot these installations requires a solid aftermarket engineering capability and experience. Not only must the engineer understand pump fundamentals, but also the application and system in which the pump is being used, as well as the changes that may have occurred in plant operating conditions since the pump was originally installed.

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The Importance of Feed Pump Barrel Inspections

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Written by: Greg James
Publisher: Pump Industry / November 2016

Rebuilding a typical boiler feed pump cartridge and returning the running clearances to specification is a critical process for effective and efficient plant operation. The cost to rebuild a cartridge – supply new mechanical seals, bearings and consumables, the lost production, down time and the labour costs – is a significant investment.

After rebuilding a cartridge and returning all operating clearances to specification, the good work can be greatly affected by installing the cartridge into a distorted barrel and/or discharge head combination.

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Middle East Power Plant Demonstrates the Advantages of Pump Health Audits

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With the help of a field evaluation, plant managers avoided unnecessary pump repairs.

Written by: Gary Dyson & Thomas Arakal
Publisher: Pumps & Systems / December 2016

 

A decade-old, 1,000-megawatt (MW) combined cycle power plant in the Middle East called an equipment repair and engineering company to conduct a pump health audit. Given the age of the plant and the fact that none of the pumps had undergone a major overhaul, plant personnel asked the engineering firm to determine which pumps should be pulled for repair at the next scheduled outage. The equipment consisted of six condensate extraction pumps and six boiler feed pumps.

Leaving the production process undisturbed, the field pump health evaluation team conducted a non-invasive pump study. Flow, pressure, vibration, power consumption, temperature and other data were collected for all the pumps in various regimes of operation. A team of engineers analyzed and compared the results of the measurements to the original design parameters. The study’s conclusions and engineering recommendations were published.

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Pipeline Receives Pump & Seal Improvements

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Seal upgrade and pump repair in the U.S. midwest boost efficiency and reliability with minimal downtime.

Written by: Ken Babusiak, John Ciffone
Publisher: Pumps & Systems / November 2016

 

Mechanical seals on pumps in the oil and gas industry often need to be upgraded to meet more stringent standards, such as tighter emissions regulations. More advanced seals also offer companies increased efficiency and reliability.

Older pumps, however, sometimes need to be modified to accommodate these enhancements because the newer parts may not be the same size and shape as the ones they are replacing. In these cases, a parts supplier can partner with an aftermarket engineering firm to come up with a long-term plan for revitalizing older pumps. The refurbished pumps can offer benefits including direct cost savings and a reduction in repair and maintenance.

An Upgrade Plan Emerges

In 2011, a field service engineer was at a pipeline station for service when a technician informed him that the company was considering overhauling all of its pumps as preventive maintenance. The company planned to investigate the possibility of upgrading mechanical seals.

The field service engineer and his team decided to analyze all of the user’s pumping stations from Illinois to Iowa—about 500 miles of pipeline. Every field service engineer who worked on the pipeline met in Cedar Rapids, Iowa, where a regional engineer led a meeting about what would be the best technology solution for this user.

The team decided to replace the existing single mechanical seals with a mechanical seal developed specifically for single-seal installations and designed to attain maximum achievable controllable technology (MACT) compliance in light hydrocarbons and other volatile organic compounds (VOCs).

Image 1. The bottom half of the coupling end bearing housing installed on the pump with the bottom half of the journal bearing, oil rings and seals installed (Images courtesy of Hydro Inc.)

Image 1. The bottom half of the coupling end bearing housing installed on the pump with the bottom half of the journal bearing, oil rings and seals installed (Images courtesy of Hydro Inc.)

The field service engineers provided information on the pumps in their area, the seal data and the coupling information. All of the pumps would require minor modifications to accommodate these new seals. The team collated information about the pumps and wrote the necessary engineering projects for the preliminary drawings. Once the drawings were approved and finalized, the pumps were sent to a pump repair and service provider to be upgraded to accept the higher-technology seal.

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