ARC Advisory Group and Plant Services recently conducted a survey targeting manufacturing operations that rely on heavy rotating machinery in a power capacity range of 200 HP to 30,000 HP. This includes heavy-duty pumps, turbomachinery, centrifugal pumps, axial compressors, reciprocating compressors, and blowers that are either used in production operations or are critical to safety.
The performance and uptime of heavy rotating equipment play an important role in business profitability in industries such as oil & gas, mining, and chemicals, and in safety for the power generation industry. However, capital-intensive industries dominate the use of these types of equipment. One of the most important metrics used in these operations is return on capital employed, which depends in large part on the availability of rotating equipment. Based on the response from our survey participants, over 80 percent of the respondents target 90 to 95 percent availability of the equipment.
Machine builders and manufacturers employ a wide variety of methods to achieve this level of availability. The purpose of this survey was twofold: 1) identify current industry practices to reach the target availability; and 2) identify the layers of protection incorporated in machinery for predictive maintenance, diagnostics, and failure analysis purposes.
Survey goal, approach and responses
ARC designed and hosted the Web survey, which solicited participants via emails from Plant Services and ARC. Between February 2015 and June 2015, we received 67 valid responses that subsequently were used in the analysis. All respondents received the final survey report.
This survey sought to identify gaps in the capabilities of currently available machine automation equipment, such as AC drives, programmable logic controllers (PLCs), and safety systems, used to implement layers of protection to detect imbalance, cavitation, vibration, and other abnormal operating conditions. The survey also identified specific technological innovations that are being employed closer to the edge of the machine control to improve layers of protection and availability with automation solutions, intelligent sensors, embedded advanced control algorithms, and predictive condition monitoring.
The roles of the respondents were: 40 percent engineering managers, 31 percent engineers, and the remainder asset managers from a wide range of asset-intensive industries. In terms of the types of businesses represented, owner/operators of machinery accounted for 50 percent of respondents, system integrators accounted for 26 percent, and the rest were either an OEM machine builder or an automation vendor. Combined, over 40 percent of the respondents were from the oil & gas exploration and power generation industries. A second tier of industries, which included cement & glass, electronics & electrical, chemical, refining, and food & beverage, combined to account for 35 percent of the respondents.
Automation for control and protection
Respondents were asked what types of automation is currently used to control the machine and prevent catastrophic failure. PLCs were used as the standard machine control in over 75 percent of the cases. Proprietary systems ranked second, while AC drives with an integrated PLC ranked third.
When implementing a layer of protection, the PLC continued to be the solution of choice; however a distributed control system (DCS) was employed over 36 percent of the time. Combined, SIL 2- and SIL3-safety rated PLCs was employed over 40 percent of the time. We interpret these results suggest that over 40 percent of the rotating equipment employs a secondary safety controller that has a SIL rating in addition to non-SIL-rated automation system. Essentially, machine builders use safety certified controllers to ensure that machines are shutdown in an orderly fashion to prevent a catastrophic event.
Sensors that identify impending catastrophic operating conditions
Imbalance, cavitation, vibration, and insipid surging often indicate impending catastrophic conditions. Rotating pumps, which include axial, reciprocating, and centrifugal, were the most dominant types of rotating equipment used in operations. Vibration was the most common operating condition identified by automation systems that could lead to a catastrophic event. Cavitation ranked as the least-used indicator, whereas insipid surging and imbalance were used equally often.