Energy-Centered Maintenance - Potential for a chemical manufacturing facility

There are three (3) major avenues of unlocking extra dollars for any manufacturing enterprise: Reliability, Efficiency, and Quality, also known as the REQ framework. With a Condition Monitoring software (such as the one offered by us at Nanoprecise Sci Corp and many others) and an Asset Performance Management (APM) software platform (such as those from AVEVA , 阿西布朗勃法瑞公司（ABB） , 霍尼韦尔 , etc.), an enterprise can achieve Reliability, Efficiency & Quality aspects in a true sense. This means that outputs of condition monitoring software such as fault mode, severity level, incremental energy consumption due to the fault, and the root cause can help as inputs for APM to create insights and incentivize actions that ultimately lead to that value realization where one can generate atleast more than 2-3x minimum RoI even on an individual asset basis (ofcourse asset HP and how often it runs matters here). In this article, we will tackle Reliability & Efficiency angle and keep the quality aspect for a later article.

Let's look at a typical petrochemical manufacturing facility. The questions we need to ask are:

-? What are the different types of assets in such a facility? Rotating Equipment (motor-driven machinery such as pumps, compressors, turbines, fans, blowers, gearboxes etc.), static equipment, valves, steam traps etc.

-? Which type of assets fail most often or need maintenance most often? (Without a doubt, it is rotating equipment from the evidence below)

-? Which types of assets consume the most energy in a plant? (More than 40% of the energy consumed in a petrochemical facility is by motor-driven machinery, as can be seen below).

Even though the Drivepower segment in the pie chart above is completely driven by electric motors, motor-driven machinery also exists in other segments, such as Boilers, Cogeneration, Other (HVAC), and Process Heating. Since motor-driven machinery is responsible for almost 50-65% of global electricity consumption, we can safely assume this number is between 20% and 60%, or around 40% of the whole plant.

As per “Energy Efficiency Improvement & Cost Saving Opportunity for the Petrochemical Industry”:

“Energy is a very important cost factor in the chemical industry in general, and the petrochemical industry is even more energy intensive than other sub-sectors within the chemical industry. The petrochemical industry is responsible for 70% of the chemical industry’s fuel expenditures and 40% of the expenditures on electricity. The costs of energy and raw materials (which are, to a very large extent, derived from fossil fuels) are roughly 2/3rd of the total value of shipments of the petrochemical industry. Because energy is such an important cost factor, energy efficiency is a very important opportunity for cost reductions.”

Thus, if the revenue of this chemical manufacturing is $20 billion (assuming 80% of it is shipment-related revenue):

Total sales from shipments - $16 billion

Total COGS from their annual report - $8.071 billion

Expenditure on electricity – 7% of $8.071 = $564 million, based on the diagram below:

Energy consumed by motor-driven machinery – 40% of $564 million = $225 million (on a conservative basis, let's assume $150 million, which is 26% of overall energy consumption).

Energy savings that can be achieved through appropriate maintenance action on a motor-driven machinery

>95% of motor-driven machinery have 6 common fault modes):

-? Shaft faults (such as misalignment, unbalance, looseness)

-? Bearing fault

-? Gear fault

-? Pump cavitation or impeller fault

Now, more than 90% of the motor-driven machinery is misaligned at any given point in time due to improper installation, ground settlement issues etc. as per the paper attached and the diagram shown below:

The graph below shows how the energy consumption increases due to misalignment offset being beyond manufacturer-acceptable alignment:

5 (1/100 mm) Misalignment offset (7% of machines in the plant) = 0% increase in energy 10 (1/100 mm) Misalignment offset (10% of machines in the plant) = 1% 20 (1/100 mm) Misalignment offset (23% of the machines in the plant) = 1.5% 50 (1/100 mm) Misalignment offset (31% of the machines in the plant) = 2.5% 100 (1/100 mm) Misalignment offset (18% of the machines in the plant) = 6.5% 160 (1/100 mm) Misalignment offset (11% of the machines in the plant) = 17.5%

The weighted average increase in energy consumption for the whole chemical plant just due to misalignment = 0%*7% + 1%*10% + 1.5%*23% + 2.5%*31%+6.5%*18%+17.5%*11% = 4.32%

So, just due to misalignment, the overall energy consumption increase in a plant is around 4.32%. Other faults can easily double it. It is safe to assume that around 10% of the energy consumption can be decreased by taking appropriate maintenance action on appropriate equipment at the appropriate time.

The total cost saved just due to energy savings achieved by the right maintenance action (that is possible through the right maintenance insight, possible through a sophisticated condition monitoring program like Nanoprecise’s) = 0.1*150 million = $15 million. Even in the worst case and most conservative scenario, this number cannot be less than $10 million (especially if one adds up the energy lost due to other fault modes, not just the shaft misalignment).

But to achieve this number, distinguishing between anomalies versus faults is important.

Because APM programs can only characterize anomalies, condition monitoring software like Nanoprecise’s can pinpoint the fault type. This will also dictate to the customer the appropriate maintenance action (like a prescriptive maintenance program).

The APM program tells when the motor is under load, but the motor can be under load due to normal operations or shaft misalignment. Determining whether it is due to normal process upset or shaft misalignment is an important aspect of incentivizing appropriate maintenance action. Without this, the user cannot understand whether to reduce production or maintain equipment. This is where the issue lies.

The customer cannot decrease his production. It’s the appropriate maintenance action where he wants to save energy. Here, he can get energy efficiency and maintenance to prevent eventual downtime.

Suppose this chemical manufacturing facility gets the APM + Nanoprecise condition monitoring software. In that case, the facility can save almost $10 million in energy and downtime savings per annum, provided maintenance actions are taken as suggested after validating them on-site.

However, to identify faults accurately, one needs a sensor that can provide high-resolution data with quality. With acceptable quality data along with a comprehensive software platform that is automated to the extent that it can perform some of the duties of a data scientist plus a reliability or vibration analyst, one can achieve the below 5 objectives necessary to achieve Energy Centered Maintenance for an organization:

-? Detect an anomaly in the data (whether vib, acoustic, flux, temp or any other data)

-? Diagnose if this anomaly relates to a mechanical, structural or electrical fault or is just a process upset

-? Calculate the remaining time to fault threshold due to the fault and select the most severe

-? Calculate the incremental change in energy consumption

-? Based on the type of fault and its severity, recommend the root cause and associated action to be taken

In the end, these outputs can be integrated with the CMMS or maintenance work order management modules of the APM system to automate work orders and, hence, close the loop.