Case Study
Oil refinery
Company: Oil refinery
Objective
solution
Results
Trap Audits Best Left to Experts
Common sense suggests that maintenance is the key to long-lasting machinery performance.
Yet steam traps are often left to their own devices, to either fail or succeed. And without a steam trap maintenance program in place, customers are certain to experience high failure rates. Spirax Sarco is helping customers to implement steam trap maintenance programs that result in energy savings amounting to millions of dollars over time.
One such customer, an oil refinery in Texas, USA was continuously experiencing a high failure rate on its 4,790 strong steam trap population (62% tracers, 6% process and 32% drips). Eventually, the steam losses were judged to be too high, and plant management asked Spirax Sarco to help reduce costs.
PLANT EXPERIENCES MORE THAN STEAM LOSS
It did not take long for Spirax Sarco’s team to notice symptoms of a highly inefficient steam system. Steam traps were improperly installed, waterhammer problems were in evidence and the condensate recovery system was damaged.
A thorough steam trap audit identified five distinct problem areas:
Improperly installed and leaking steam traps
Freezing sulfur
Waterhammer
Wasted blowdown
Steam turbine inefficiencies.
ACHIEVING ABOVE AND BEYOND THE INITIAL SCOPE
Problem 1: The Spirax Sarco team identified process traps that were not properly installed. For example, in the heavy oil cracking vapor recovery unit, the float and thermostatic steam traps were installed upside down and leaking steam. Proper installation led to annual savings of $235,784.
Problem 2: In the Complex 7 Sulfur Loading Rack, sulfur was freezing due to backpressure, dirt problems and incorrectly sized or selected steam traps. Spirax Sarco recommended UIB30 inverted bucket traps to solve this problem.
Problem 3: Waterhammer problems were found in the main condensate header by the hydrogen unit. The Spirax Sarco team identified the culprit as a leaking, high-pressure steam trap. Another area with potential waterhammer issues was tracked down to a 450 psig steam line between the cogeneration unit and Complexes 7 and 8, where over 40% of the steam traps were either missing or cold. The Spirax Sarco team recommended installing TD62LM thermodynamic steam traps, new isolation valves and strainers with blowdown valves where necessary.
Problem 4: A damaged boiler blowdown heat recovery exchanger was dumping blowdown into the sewer. Our inspection also found design issues that were causing corrosion and waterhammer. In fact, the heat exchanger shell was already showing signs of damage. The team recommended the installation of a new Spirax Sarco heat recovery package. If installed, it will allow the plant to recover the majority of energy available in the blowdown line with projected savings totaling just over $900,000 every year.
Problem 5: Steam turbine inefficiencies led the Spirax Sarco team to perform a plant-wide assessment of every unit in operation. The team suggested opening all of the bleeding valves and installing steam traps throughout the turbine casings and inlets to keep them free of condensate and to avoid steam waste. The potential for savings is just under $150,000 per year. Spirax Sarco also recommended complementing the plant steam trap management program with a detailed steam leak survey and air/nitrogen leak survey. This has lead to additional annual savings opportunities of $160,000 and $460,000 respectively.
ACTIVE STEAM TRAP MANAGEMENT CAN NET MILLIONS FOR OUR CUSTOMERS
Once Spirax Sarco was able to demonstrate the enormous savings possible with steam trap audits, annual checks became standard. The solutions provided by Spirax Sarco have resulted in reducing the customers annual operating costs by significant amounts, reaching $778,000 in only one year (2001) and reaching $4.7 million by 2006. With the new steam trap program in place, the plant’s failure rate reduced from 5.5% in 2001 to a much lower 1.5% in 2006. If the steam traps had been left alone, we project that the failure rate would have tripled, from 5.5% in 2001 to 16.5% by 2006.
“Each year, Spirax Sarco surveys all traps within our facility using infrared and acoustic tools to locate dysfunctional traps and evaluate the associated energy loss,” said the plant’s Complex 3 Operations Manager. “Based upon these findings, each trap is scheduled for repair or replacement. The program has been in effect for several years and has resulted in significant steam savings at our facility.”
Despite customer skepticism, budget constraints and limited manpower, the Spirax Sarco team had demonstrated the importance of active steam trap management. In fact, the customer is so pleased with the project results; they have encouraged their accounting team to uncover additional steam system inefficiencies, finding opportunities that could translate into several hundred thousand dollars of additional savings for the plant.