Food processing has a 'waste heat' problem

Thriving and building a sustainable food & beverage (F&B) business in a prevailing buyer’s market has brought up two key challenges: keeping operational costs optimised and demonstrating a commitment to the environment.

In recent times, decarbonisation has emerged as a common solution to both challenges, creating a sudden shift towards renewable energy sources. But are we at risk of creating another ‘cobra effect’ of generating a new set of problems whilst resolving current problems? Meaning, could an industrywide switch to renewables at this time cause more harm than good? With rising energy prices and limited grid capacity, widespread shifts to electricity could overburden the energy grid and cause prices to soar, crippling business and hurting the economy. The fact is our renewable energy solutions aren’t quite ready to support the world’s energy needs.

Then, what can be done in the meantime? Can organisations still cut back on emissions without cutting production output? Yes.

But before making any major energy decisions, some of which may lead to expensive overhauls to plant infrastructure, F&B companies should take a hard look at all options. What is right for one facility may not be optimal for the next. And whilst a path to net zero emissions might not be visible from the outset, it does become much clearer when organisations follow a three-step process that begins first with minimising process parameters, followed by optimising utilities and finally developing a roadmap to complete decarbonisation.

Let’s take a closer look at how this process unfolds.

Minimise

It is imperative that organisations first dive into the manufacturing processes and establish a baseline of thermal utility generation, including fuels and energy used, efficiency, operational practices and heat usage. A thermal energy expert will take a detailed look at the input operating temperature and pressure of systems to ensure they are at the required settings for the desired process output. At this point, a scope can be developed to minimise those input parameters and lower energy use by applying solutions such as reducing setpoints, upgrading process equipment and decreasing cycle times.

Optimise

Right now, most companies rely on carbon-emitting energy sources, and they will continue to do so until their energy is fully renewable. Between now and then, optimising facilities to use as little energy as possible is key.

Unlike other sectors, including heavy industry, food plants produce a lot of waste heat through cooling and process whilst simultaneously needing heat at relatively low temperatures (below 121°C). This positions the food industry perfectly for applying an optimisation strategy we call Circular Thermal. By implementing an internal process heat exchanger network and industrial high-temperature heat pumps, plants can recover waste heat and displace fossil-generated heat, achieving up to an 80% total carbon reduction.

This three-step process first includes de-steaming (conversion to pressurised hot water) all applications below 121°C. Why is de-steaming so important? The power needed to generate steam is much more intensive than maintaining hot water. If steam is needed, however, then we may look at sustainable steam trap solutions with real-time monitoring of traps and trap failures to reduce steam loss and improve efficiency.

After deciding on whether steam or hot water is appropriate, we move to the recovery of direct heat when a positive differential temperature is available. Finally, using industrial heat pumps, we raise the temperature of low-grade heat to the temperature that is useful for the process. This strategy can be used across the food industry and can help plants knock off 50% of their primary energy demand just by applying it.

Decarbonisation

Once complete optimisation is achieved and the plant has realised a steep drop in demand of the energy generation source, we arrive at the third and final step of selecting and sizing an optimum source of a non-fossil-fuel energy source. By removing the small amount of remaining greenhouse gas (GHG) emissions with a non-fossil-fuel energy source, a plant can achieve net zero emissions.

This approach is much more affordable than outright switching to renewables without addressing the massive amounts of wasted energy that plants would produce if nothing else changed. Beyond the extremely high burden to a company’s bottom line, if companies industrywide followed suit and did not address the energy waste, we could be looking at a situation where the energy grid becomes overtaxed. This would lead to extremely high energy costs, possible disruptions in energy availability or even damage to the economy. Now, if non-fossil-fuel energy solutions are not available in certain regions or are insufficient to support a specific plant or facility, we may look at installing carbon capture on fossil-fuel installations.

Conclusion

This three-step process to decarbonisation is the optimal way to achieve net zero emissions because it is one of only a few strategies that brings a return on investment.

We are living in a critical time when F&B companies across the world are uncertain of their path forward. As energy prices continue to rise, regulatory demands tighten and our grid capacity becomes increasingly strained, there’s a fear that we are headed towards difficult times. Fortunately, there is a sustainable way forward — one that not only cuts emissions and reduces energy demand but also improves operational costs. By minimising energy use, optimising systems to ensure maximum efficiency and decarbonising energy generation, in that order, companies can seamlessly navigate this energy transition and ensure they won’t be left behind.

Image credit: iStock.com/jordachelr