The EIA recently reported there are 135 operable petroleum refineries in the U.S. as of June. With only 18 of these refineries built after 1975, the bulk of them are 45-100 years old. Environmental regulations, refining process improvements, energy efficiency, safety concerns and product demand impact thousands of centrifugal pumps pushing product through old refineries.
Figure 1. Original 10-stage JTC was replaced with a six-stage Conhagen pump.
Environmental regulations are concerned with fugitive emissions of product, seal buffer fluids and lubricating oil. Congress' first attempt at clean air, the Air Quality Act of 1967, was a failure. The Clean Air Act of 1970 introduced regulations with statutory deadlines for enforcement. Highly motivated refiners began replacing packing with mechanical seals in all pumps with hazardous pumpage. Many early mechanical seal retrofits failed because the old pumps relied on packing's damping and stiffness characteristics for smooth operation. A collaboration between users and pump and mechanical seal manufacturers developed the most popular retrofit of single-stage overhung process pumps: replacing everything except the impeller and volute. It was popular because the improvements did not affect the piping, baseplate or driver.
During normal pump refurbishment, Conhagen's mechanics identify and record worn and damaged parts. When unusual damage or premature wear is discovered, Conhagen sends an as-found report to the customer with recommendations for repair or upgrade. Customers are eager to reduce their cost of ownership by extending mean time between repairs, mitigating damage during normal operation and improving performance. Conhagen partners with them to identify the root cause of premature wear or failure and develop solutions.
Drop-in replacements are extreme upgrades that are expensive, complicated and only justified by reducing total cost of ownership. Conhagen recently replaced a 10-stage axial-split-type pump with a sixstage barrel-type pump (as seen in Figure 2) in 450-degree Fahrenheit diesel fuel, nonspared service. The plant's piping was unchanged, and the driver was not moved. Installation, including welding of the new pump pedestal to the existing baseplate, took one day.
For more than 25 years, this axial-split pump required overhaul every 18 months. Since 2012, the Conhagen replacement has run without any service to the bearings, seals or pump.
In 2015, Conhagen replaced a 450-horsepower screw-type pump (shown in Figure 3) in 350-degree Fahrenheit vacuum tower-bottoms service with a three-stage centrifugal pump. A new baseplate supporting the replacement motor, pump and coupling was grouted to a clean concrete surface created by a diamond wire saw which cut the original pump baseplate from the foundation. The replacement pump flanges mated to the existing piping. Again, the mean time between overhauls has been extended from weeks to years, with only one outage during this time due to a cold start (the pumpage is solid when cold).
Conhagen designs and manufactures unique pumps for industry regulations and customer applications. Its staff of experienced engineers apply state-ofthe- art engineering and manufacturing processes to all work. Conhagen can confidently reverse-engineer existing components using Faro arms, laser scanners and laser trackers. In-house software quickly produces hydraulic and aerodynamic components. Computational fluid dynamics software helps optimize the geometry and confirm the performance of the components. The latest finite element analysis codes allow designers to quickly assess stress, deflection and thermal effects on the mechanical design and interaction with other components. Conhagen also uses Turbomachinery Research Consortium's rotordynamic software suite, XLTRC2, for lateral and torsional vibration analysis. These are the same tools OEMs use, but in the hands of the engineer assigned to the job.
Customers can talk directly to Conhagen's engineers. The assigned engineer is responsible for the project from beginning to end. They visit the jobsites, develop and present proposals to the customers, negotiate the final work scope and deliverables, perform the work, keep the customer apprised of progress and then help the customer write management of change documents. Large projects require a project manager to maintain communications and provide schedules to the customer and vendors while the engineer focuses on the work.
Customers can visit Conhagen's shops anytime to audit progress, witness events or discuss technical issues. When the project is completed, customers receive a report containing as-found, as-shipped dimensions, positive material identification of components, certified material test results for provided materials, balance reports and copies of all dimensional drawings of components provided (including specifications of materials, heat treat and processes). After all, the pump belongs to the customer, not Conhagen. When rerates affect the configuration or operation of the equipment, Conhagen also provides installation, operation and maintenance manuals.
Conhagen is a small business but has big capabilities. Each member of Conhagen finds it exciting and rewarding to solve problems for its customers.
For more information, visit www.conhagen.com or call (409) 938-4226.
