BAMBOO: Optimising waste and being flexible with energy

Can heavy industry be more sustainable? This is the question at the heart of most projects in this publication and one that visitors to the BAMBOO project website see before anything else. The site then goes on to showcase just how the project is working to ensure it can be. BAMBOO’s aim is, therefore, a simple one – to enable energy intensive industries to adapt their current production patterns to use more fluctuating renewable energy supplies and make better use of the waste streams they produce.

The project is working towards this objective by addressing these energy and resource efficiency challenges through new technologies. This work focuses on developing novel solutions that provide better information about integrating variable and non-programmable energy sources, and allow industry to improve its flexibility in terms of the supply of electricity it uses and to decrease its consumption and dependence on fossil fuels.

The technologies being developed by BAMBOO focus on three main innovation pillars: waste heat recovery, electrical flexibility and waste stream valorisation, enabling industrial companies to make better use of waste resources that are currently often lost. Utilising waste products like heat and gases, as well as being able to be more flexible in terms of renewable energy use, will ultimately increase industrial competitiveness.

“When we are talking about energy intensive industry traditionally, we refer to industries whose main aim is to produce as much as possible using whatever energy is needed to make this happen,” explains BAMBOO’s Jorge Arroyo. “This has changed in recent years, with the European Commission funding the kind of projects that make processes more energy efficient.

“We know that in the process industries there are a lot of waste streams, often producing gases that can be used but often are not,” he continues. “Many companies just don’t know how to use these gases, while those that do use them could perhaps use them more efficiently.

“That’s why our focus is on the technologies that use off-gas and waste streams produced by process industries more efficiently, making them more energy and resource efficient.”

Waste heat

In terms of waste heat recovery, BAMBOO is developing technologies that will capture the heat within liquid streams produced in the steel-making process. Using high-temperature heat pumps at the Arcelor Mittal steel plant in Spain, it is enabling low and medium grade waste heat produced in the process to be upgraded to higher temperatures, which can then be used to optimise the process.

“They have big furnaces producing a lot of waste heat streams that can be recovered,” explains Arroyo. “What we realised is that many companies have not characterised these streams. They know that they are producing hot gases and that this energy can be used, but they don’t have the technologies in place to be able to use it. So, we have upgraded one of these streams, which we are now working on to enable the use of steam produced by the boilers to supplement the use of natural gas in the process.”

BAMBOO’s second use case for waste heat recovery is in the petrochemical sector, working with Tüpras in Türkiye, using organic rankine cycles (ORC) to produce electricity. This process uses organic, high molecular mass fluid with a boiling point that occurs at a lower temperature than water to steam, allowing for heat recovery at lower temperatures, which can be converted to electricity.

“This is not a new technology, but the novelty we are introducing is that we will use a real stream,” adds Arroyo. “This means we use technology to mitigate oscillating flows from the process to work at optimal levels.

“This has always been a challenge in the petrochemical industry where variable temperatures in the waste streams have been a problem for technology providers looking to make use of the wasted heat,” he continues. “Another challenge for BAMBOO is to adapt the existing ORC technology to be able to operate in a harsh environment subjected to restrictive regulations. We hope to demonstrate this technology at Tüpras and then to be able to scale up to an industrial scale.”

Electrical flexibility

The second innovation pillar for BAMBOO is electrical flexibility, and here the project is working to provide industries with a greater flexibility of energy use, involving the integration of renewable electricity sources and storage solutions. This strategy also includes the potential to provide electricity to the grid and so will lower overall energy costs for industry, too. Electrical flexibility also involves a demand response approach – adapting processes that use electricity to be able to use it when it is cheaper, so when availability is high and prices are low – in the case of renewables, when the wind is blowing and the sun is shining.

To demonstrate these technologies, BAMBOO is working with paper and pulp company UPM in Germany where a virtual, seasonal battery is being developed that will store energy when there is high photovoltaic production of electricity in the summer, to be used when electricity prices are high in the winter. Connected to the grid, this will also help provide grid stability.

Key challenges the project faces here include the fact that paper mills often generate energy on-site in combined heat and power plants, relying mostly on fossil fuels to cover the high demand for electricity and heat. Meanwhile, many companies are on fixed electricity contracts and are in production 24/7 and so it is difficult to be flexible in their use.

“At UPM, we are trying to demonstrate how the whole plant can be used as a virtual battery and optimise the way that electricity is consumed,” explains Arroyo. “They are trying to adapt their production process to times when there is high photovoltaic production of electricity using an optimisation tool aligned with forecasted/actual renewable power generation and grid demand.”

Waste stream valorisation

Waste stream valorisation is the final innovation pillar on which BAMBOO is focusing its efforts. The project is exploring the calorific values of various waste streams that, when valorised, can be used as fuel in the plant itself or sold to other plants, so becoming a revenue stream. The valorisation will largely consist of replacing fossil fuels with off-gases produced as waste using improved combustion monitoring systems and the use of low NOx emissions burners combined with biomass.

This technology is being demonstrated at the steel plant at Arcelor Mittal in Spain and at Grecian Magnesite mineral plant in Greece. Processes at the Arcelor plant produce gases, some of which are already being used to replace natural gas. For example, the blast furnace gas produced has a low calorific value so is difficult to re-use or for it to replace natural gas. By monitoring the combustion in the furnaces, they already control the high temperatures needed using the blast furnace gas mixed with natural gas, but BAMBOO is working to enable more of the blast furnace gas to be used and so reduce the amount of natural gas needed.

“BAMBOO is developing a flame monitoring system that will help the plants have better control of the flames,” explains Arroyo. “This way they will be able to control the mix of gases better, and so maintain the high temperatures needed in the process and control the quality of the steel being produced.”

For Grecian Magnesite, the objective is to increase the use of biomass fuel in their processes, while still maintaining the very high temperatures needed to produce caustic calcined and dead burnt magnesia. Currently, coke is used which produces a large amount of CO₂ (MgCO₃ thermal decomposition) along with NOx and CO₂ emissions. Being able to replace the coke with high-quality biomass will help reduce these emissions and allow for flexible consumption based on market prices.

“By valorising waste streams like this, as well as capturing the waste heat produced and utilising this heat within the processes, and adopting electrical flexibility, we hope to be able to help increase efficiencies, reduce harmful emissions and lower overall production costs at all the plants we are working with,” concluded Arroyo.

“In turn, we hope that by demonstrating how these new technologies can deliver, we are also clearly showing that they are transferrable and replicable in other process industries where heat is produced, waste streams created and electricity used.”