According to a Solomon study of 116 chemical plants across Europe, the Americas, Asia, and the Middle East, compressor failure was the second leading cause of all downtime and slowdowns between 2009 and 2013. István Bognár and Tibor Poór, head process engineers at MOL Petrochemical, know this first-hand.
Recently at the company’s plant in Hungary, the two engineers were looking for a way to prevent impulse pipe plugging on the facility’s critical cracked gas compressors. When the compressors ran normally, gas pressure fluctuated inside impulse pipes. But when fouling from process gas accumulated on impellors or discharge lines inside the compressor, or if a leaking connection caused continuous flow inside the pipe, blockages in the impulse pipes were threatening to trip the units. Making the matter more complicated, the degree of deposit could only be seen after the compressor had been disassembled.
Bognár and Poór decided to use the unique diagnostic capabilities of Emerson’s Rosemount™ 3051S remote pressure transmitter. The transmitter counts the number of plugging alerts it detects until it reaches a preset number of alerts, at which point it sends a signal to the DCS. When the compressor is cleaned, the counter is set to zero by a reset switch. Integrating the analysis of pressure data using Emerson’s AMS Device Manager allows for the correlation of other operation parameters such as material flow rate. A similar function could also be programmed into the PLCs of the compressor manufacturer. A regular email is automatically sent to plant decision makers that analyzes the trend data of the previous eight hours, including pressure trend data, counter value, position on the DCS screen, possible thickness of the deposit, and time since previous maintenance. This has proved invaluable to understanding the status of compressor health at all times.
Bognár and Poór say the asset monitoring solution has made it possible to take a more proactive maintenance approach that has cut costs and improved plant availability. Some of the business benefits have included preventing unplanned shutdowns at an estimated savings of a minimum $5 million per event, and preventing unexpected machine failure, which can cost $1 million per year. Using the transmitter failure prediction tool the plant is also better prepared for cleaning activities or for diaphragm changing. Early planning of cleaning shutdowns can help save on the $2 million cost per shutdown. In addition to preventing environmental issues caused by flares, optimization of chemical dosing, which costs about $5 million per year, is possible. Reducing turbo machinery energy through steam consumption is another benefit, and at an estimated cost of $1,000 per day, could provide a significant boost to the plant’s bottom line as well.
How have you used smart devices to improve asset reliability at your plant? Comment below.