A Case Study: How to Upgrade, Improve, and Redesign Turbomachines

Many plants have experienced a shutdown due to operational challenges or equipment failure. Increased reliability, better operational processes, and higher-performing turbomachines help reduce downtime and unforeseen hurdles. Most plants have a working list of improvements and modifications for their turbomachines, such as compressors, pumps, turbines, fans, blowers, etc. Some manufacturers and vendors are even trying new and innovative turbomachinery/equipment solutions to increase their market share and profits.

COMMONALITY & SIMPLIFICATIONS

Commonality and simplifications are keys to success and profitability. Developing different solutions for various operators and plants is wasteful, time-consuming, and expensive. Rather, developing a universal family of turbomachines suitable for separate operators and plants in different countries and regions is advantageous.

Evaluate all feedback and improvement requests from different operators and units and develop a common solution. Simultaneously, there may be ways to simplify a turbomachine’s auxiliary components, such as replacing several components with one part, eliminating unnecessary parts and pieces that may not be needed, etc. Fewer size variations for hardware, bolts, fasteners, connections, and others are best. For example, one turbomachine’s bolts and nuts were one of two sizes. In general, fewer hardware varieties, whether bolts, connections, machinery pieces, subsystems, etc., are a benefit. Aim for commonality in all aspects of design and manufacturing.

The commonality of parts and pieces is important, as it saves costs and avoids complications. Improvements, changes, and developments should first consider a common solution.

HIGHER RELIABILITY & FEWER CHALLENGES

Many turbomachinery operators are shifting from preventive and time-based maintenance to condition-based maintenance. Some operators prefer longer intervals between routine maintenance and overhauls. A promising approach is replacing the gear unit or lube oil to extend lube-oil replacement intervals from every two to every three years. This change could be beneficial, but it must not compromise the turbomachinery’s reliability, operation, or safety. Therefore, extensive checks, studies, and assessments are typically required to implement this improvement.

As a consultant for a major turbomachinery packager, I observed that all development projects were focused on preventive maintenance and improving efficiency; however, this narrow focus should not overshadow the importance of overall operation and maintenance. There is a growing trend in plants to extend operating time between overhauls and preventive maintenance. Additionally, new concepts like predictive maintenance, condition monitoring, condition-based maintenance, optimized maintenance schemes, and other modern approaches are gaining significant attention in the fields of operation, reliability, and maintenance.

ACCESS, SPACING & SMART CONFIGURATION

In many initial turbomachinery package designs, allocated spaces for access, operation, and maintenance are often inadequate, and sometimes access to specific subassemblies or subsections is entirely overlooked. If the existing configuration doesn’t provide sufficient space for a particular installation, a different layout should be considered, ensuring necessary access based on field operation feedback.

Intelligent design is crucial for enhancing operational efficiency and maintenance. For example, in a redesigned turbomachinery package, the casing might be opened on one side to allow access and installation of internal components without disturbing the attached piping on the other side. Additionally, removable legs on the turbomachinery stand can simplify the placement and future removal of the unit.

EASE OF ASSEMBLY

To support installation and assembly teams, target ease of assembly and disassembly. For example, joints can be machined for better matching; proper marking can speed up assembly and reassembly.

MECHANISMS IN TURBOMACHINES

Many turbomachine mechanisms operate in a 3D environment that makes their design, configuration, and operation challenging. Often, the goal or target of these mechanisms is ambitious, but insufficient time and resources are allocated to design, simulate, test, and verify them. Underestimating and simplifying can lead to malfunctions, as many mechanisms have complex systems, therefore thorough assessments and verifications are needed.

OPTIMUM SENSORS, INSTRUMENTS & CONDITION MONITORING

Many operators complain about reliability, operational challenges, high vibrations, and dynamic problems. A common request is to install sensors and a condition-monitoring system to predict impending failures and conduct root-cause analysis.

ALIGNMENT, BALANCING & TOOLS

Alignment and balancing are important for better and safer operation, increased reliability, and less vibration. Tools that increase field balancing or field alignment, including field balancing provisions, alignment tools, etc., improve turbomachine health.

CASE STUDY: ELIMINATION OF SAFETY CLUTCH IN A TURBOMACHINERY PACKAGE

In a turbomachinery package, a safety clutch was installed between the electric motor driver and the gear unit to act as a torque limiter, preventing excessive torque transmission in an emergency. The external clutch also served as a brake because the original electric motor was not equipped with one; however, the clutch became the source of numerous operational failures.

It didn’t make sense to keep the emergency clutch, and after extensive negotiations with the electric motor manufacturer, both parties agreed to incorporate a built-in brake and torque limiter into the electric motor itself. As a result, the external safety clutch was removed from the turbomachinery package.

The electric motor was then directly connected to the gear unit, resulting in a cheaper, more compact, lighter design with improved overall reliability and safety. This new configuration also led to a reduction in costs and enhanced reliability, availability, and performance. Additionally, eliminating the clutch re-engagement process simplified the overall operation of the turbomachine. Many preventive maintenance tasks associated with the safety clutch and its connections were also eliminated.

About the Author

Amin Almasi is a Chartered Professional Engineer in Australia and the U.K. (M.Sc. and B.Sc. in mechanical engineering). He is a senior consultant specializing in rotating equipment, condition monitoring and reliability.