Magazine process newsMagazine process news

Site ExplorerSite Explorer

Savvy Maintenance Doubles Savings

Condition Monitoring

Dedicated software modules from Siemens monitor mechanical assets in process plants, enabling preventive maintenance and contributing to increased safety and reduced downtimes.

Pumps, positioners, heat exchangers, and compressors are a part of almost every plant in the process industry. Issues with these mechanical components can affect the entire plant, so their states need to be constantly monitored and evaluated. As mechanical assets typically do not provide any state information automatically, plant operators have confronted this problem with redundant installations or the implementation of additional special sensors and condition-monitoring systems. However, both solutions involve significant costs.

Mechanical assets such as pumps are key components of many plants in the process industry. Failure of these assets negatively affects the entire plant

Intelligent diagnosis from the process data

Dedicated software modules from Siemens make such add-on solutions unnecessary. As indirect diagnosis tools, they determine and evaluate the states of mechanical assets directly from process data readily available in the control system. For this purpose, the tools compile and evaluate relevant analog and binary values, establish logic connections, and trigger a corresponding pre-defined maintenance message to the operator via a communication interface. In this way, the modules issue alerts to prevent the damage of assets by unfavorable operating states or when wear limits are being reached. If desired, active intervention into the operation of the mechanical components is also possible using the modules, but this feature is not activated by default. Upgrading the modules does not impact the process itself.

Expertise and experience gained in the field

Siemens has been active in the fields of plant engineering and process control for decades. The company has also always collaborated closely with industry partners on the development of new, innovative solutions: The software modules for pump monitoring were developed together with plant operators and pump manufacturers. The experience gained from this has paid off again with the intelligent diagnosis modules for mechanical plant components and their integration into the plantwide asset management of Simatic PCS 7. In addition to software modules for pump monitoring, there are now additional modules for monitoring valves, heat exchangers, and turbocompressors.

The systematic integration of mechanical assets into condition monitoring and plantwide asset management using such intelligent diagnosis modules enables preventive maintenance and offers substantial benefits: cost savings, high plant availability, and prevention of unplanned downtime. At the same time, this integration creates the basis for performance monitoring and supports measures to increase efficiency and to achieve a high degree of process reliability and a consistently high product quality.

(All photos: Siemens AG)

Condition monitoring with Simatic PCS 7

For monitoring the status of mechanical assets with the Simatic PCS 7 plant asset management, Siemens has developed a series of diagnosis modules that serve as proxies for certain mechanical assets such as pumps, valves, and heat exchangers. This approach is based on an intelligent evaluation of sensor signals that are already available in the control system and does not require additional sensors such as structure-borne noise or acceleration sensors.

  • PumpMon: The diagnosis module PumpMon determines limit-value violations of the pumps’ rated operating range and deviations from the expected characteristic curve, reports them to the user, and makes them available for further processing. PumpMon can provide support for the optimization of the pump design through recording and statistical evaluation of the operating data of the collective load. At the same time, the software enables identifying existing potential for energy savings.

  • ValveMon: Like pumps, valves are among the most widely used actuators in process plants. Abrasion, cavitation, valve cone corrosion, scaling, and fouling are among the most common wear phenomena. The ValveMon module monitors valve states based on corresponding process values and enables detecting malfunctions and impending failures early on, supporting optimized maintenance planning and contributing to an improved availability of the entire plant.

  • HeatXchMon: The primary problem with heat exchangers is fouling. Residues of the process medium form and build up on the heat exchange surfaces, reducing efficiency. HeatXchMon determines deviations from the reference heat flow for precise calculation and display of the current degree of fouling, energy loss, and daily costs.

  • CompMon: Turbocompressors have no mechanical parts subject to wear over time. Depending on the type of conveyed medium, however, the aerodynamic performance can be reduced by contamination, caking, or abrasion. The operating set point can also change through fluctuations in the suction-side medium temperature, pressure, or composition, or through flow resistance changes on the pressure side. The CompMon module calculates key performance figures (e.g., conveyance or efficiency) and issues an alert if the corresponding values indicate damage to the compressor, accumulation of dirt particles on the rotor disk, or liquid-impact erosion of the blades.