FOR the efficient management of plant operations, the critical considerations for the energy manager include product quality, safety, downtime, and, of course, energy use. A production plant in Germany has set a greenhouse gas emissions reduction goal of 25% by 2030 (using 2015 as a baseline) and turned to the plant energy manager to help deliver that target.
Sanid Usanovic reviews how a German food and beverage plant uses the Fluke ii900 Industrial Acoustic Imager in standard maintenance to save energy significantly.
Reducing environmental impact
Manufacturing firms worldwide are reviewing the efficiency of operations to reduce costs and drive down their environmental impact. Led by sustainability officers’ with the support of energy managers, efforts to lower energy usage are helping to decrease the environmental impact of production and contribute to global and local efforts to reduce climate change.
In 2011, the International Organisation for Standardisation (ISO) introduced a new voluntary standard for designing, implementing and maintaining an energy management system. A technical committee undertook the development of ISO50001. Like other ISO standards, it is intended to be realised across various industries and encourages adopters to implement a Plan, Do, Check, Act framework for energy management. Since the Paris Agreement of 2015, the drive for ever more sustainable operations and to reduce the effect of climate change has accelerated.
This company is taking a stand against climate change and has committed to reducing greenhouse gas emissions. One crucial program element focuses on reducing the plant’s indirect emissions from energy use. Specifically, this considers the emissions resulting from the generation of the electricity purchased by the company from the utility provider.
For the bottling plant in Germany, one area under review was how to tackle the energy wasted through leaks in compressed air systems. The Carbon Trust estimates that the UK industry uses over 10TWh of electricity to produce compressed air, making it the direct root cause of over five million tonnes of CO2 emissions a year.
The cost of compressed air leaks
The energy consumption at the food and beverage processing plant compressed air systems was at R6 million. It is estimated that if there were no maintenance system in place, the losses due to leaks in the network would be between 25-30%. Implementing a maintenance regime from this starting point would represent a potential energy cost saving of R2,4-R3 million per year for the plant in question. Whilst desirable, it is doubtful that any plant will achieve a 100% leak-free compressed air system. The target for good practice is between 8%-15%, and for best practice is 6-8% energy losses due to leaks.
Maintenance methods
When looking for leaks, it is essential to remember that some components of a compressed air system are especially vulnerable, such as pneumatic cylinders, flanges, filters, tools, presses and drop hammers, which should be checked first.
Some traditional ways of detecting leaks include listening for hissing sounds or coating joints with soap and checking for bubbles. The soapy water method is inefficient and inadequate for a manufacturing facility’s size and scope of compressed air lines. Many cannot hear the hissing of air leaks in a quiet environment, let alone a functioning bottling plant. An improvement on the soap and water method was ultrasonic leak inspection.
Ultrasonic tools use microphones to identify the sounds associated with escaping air/gas.
In a range of about 38 to 42 kHz. They convert sound captured in this range into audible sound and rely on human hearing to identify whether a noise is a leak. That makes the detection subjective and reliant on enhanced skills and training.
Large manufacturing companies like this one may outsource checks and inspections for leaks in compressed air networks. Specialist companies will carry out annual checks that could deliver what would be considered good practice levels of leakage, between 8-15%. However, a new testing regime less reliant on annual checks through a third-party vendor was sought to decrease the energy losses further by reducing leaks in the network.
The food and beverage production plant agreed to test the use of industrial acoustic imagers at the plant to check for leaks in compressed air systems. Recent developments in industrial acoustic imagers, such as the Fluke ii900, mean they are equipped with an array of microphones, providing visualisation of sound field within an expanded field-of-view, that enables maintenance teams to visually locate air, gas, or vacuum leaks very quickly and accurately in compressed air systems. This means it is possible to detect leaks even in noisy environments and from a distance, and as such, maintenance programs can be adopted whilst the plant is operational.
The detected leaks are then displayed on an LCD, making it possible for a user with little-to-no experience to detect leaks immediately. The acoustic imagers can evaluate the distance to the target and estimated size of the leak, making it easier to prioritise a repair schedule.
Solar loading and wind are environmental factors that must be considered. Solar loading occurs when one or more sides of a structure are uniformly heated by the sun, causing temperature differences to be masked. Similarly, wind moving over a structure can wash away thermal signatures or create unexpected pressure differences, leaving some problems undetected.
The food and beverage production plant has started using the Fluke ii900 to locate compressed air leaks. The equipment is capable of reporting an estimation of the size of the leak. From that data, it is possible to estimate the company’s energy cost and evaluate the return on investment.
