Waste heat

Last month, Evonik Industries AG (Essen; ) and Uniper (Düsseldorf, both Germany; ) launched the Technical Options for Thermal Energy Recovery (TORTE) project in Gelsenkirchen. As one of the first phases of Evonik’s Herne Green Deal to sustainably transform the Herne chemical site, the TORTE project will feed industrial waste heat from isophorone production into the district heating network. Around 1,000 homes in the Ruhr region will be supplied by the end of 2024.

To recover this industrial low-temperature waste heat, Uniper has installed a large onsite heat pump to feed up to 1.5 MW of heat into the district heating network to supply local customers. This sustainably recovered heat from the Herne site will help Uniper to reduce its emissions by 1,750 ton/yr of CO₂. The project also supports Evonik’s sustainability ambitions to reduce carbon emissions and its use of fossil resources at its sites.

Limescale

A research team from ETH Zurich (Switzerland; ) and the University of California, Berkeley () has developed a limescale-repellent coating that prevents the adhesion of limescale crystals. The researchers examined — at the microscopic level — the interactions among individual growing limescale crystals, the surrounding water flow and the surface. Based on this, the team developed several coatings from various soft materials and tested them in the laboratory at ETH Zurich. The most effective coating was a polymer hydrogel, the surface of which is covered in tiny ridges formed in microtextured molds that were fabricated by photolithography. In boilers, the riblets ensure that the limescale crystals have less contact with the surface, so they cannot adhere and are thus easier to remove; water flowing over the hydrogel and through the ribbed structure carries them away. While the coating can’t fully prevent limescale crystals from forming, the constant passive removal of the microscopic crystals stops them growing together to form a layer.

Rather than applying for a patent for their development, the researchers have deliberately decided in favor of publication, which appeared in a recent issue Science Advances. This means that all interested parties are free to further develop and utilize the new coating.

Copper recovery

Last month, BASF SE (Ludwigshafen, Germany; ) and hydroGeophysics Inc. (HGI; Tucson, Ariz.; ) announced an exclusive partnership aimed at combining expertise in mineral processing, hydrometallurgy and deep-well injection. The collaboration aims to optimize copper extraction in the mining industry by utilizing HGI’s geophysical techniques to identify areas within the heap that currently offer poor recovery and will involve the design and implementation of a deep-well injection program, incorporating BASF’s LixTRA leach aid to facilitate a significant uplift in copper extraction. The heap leach process, which involves piling low-grade ores onto a liner and dripping a lixiviant (usually acid) over the heap to dissolve copper into solution, offers a cost-effective method for copper extraction. However, the non-uniformity of heaps often leads to areas of ore compaction and poor lixiviant permeation, resulting in suboptimal recovery of metal. HGI employs geophysical technologies to characterize the structural components of the heaps, enabling the design, operation and monitoring of targeted lixiviant injection wells. By adding BASF’s LixTRA leach aid, greater ore-lixiviant contact is made, which ultimately leads to higher copper dissolution and increased metal recovery. Initial results from a client’s site have demonstrated a 20% increase in copper recovery during the trial period, prompting further testing on a larger scale to quantify the benefits.

Ceramics

Earlier this year, the E.U. Horizon project eLITHE (Electrification of ceramic industries high temperature heating equipment) was launched to advance the decarbonization of the ceramics industry. The four-year project is coordinated by Fundación CIRCE (Zaragoza, Spain; ), with participation of experts in the ceramics and electrification sectors — 18 partners from nine European countries. It will showcase innovative, sustainable and cost-effective pathways for electrifying high-temperature thermal processes, such as melting, calcination and firing.

Among the new technologies being demonstrated are microwave-assisted heating at Mytilineos S.A. (Marousi, Greece), flexible hybrid H₂ burners at the Brick and Tile Research Institute (IZF; (Essen, Germany) and electric technologies at Torrecid S.A. (Castellón, Spain). Its enabling technologies will involve smart control through digital twins, novel sensors and materials, and high-temperature energy storage.

Plastics

A team of scientists from Nanyang Technological University, Singapore (NTU Singapore; ) has developed an artificial “worm gut” to break down plastics. By feeding worms with plastics and cultivating microbes found in their guts, researchers from NTU’s School of Civil and Environmental Engineering and Singapore Center for Environmental Life Sciences Engineering have demonstrated a new method to accelerate plastic biodegradation.

Previous studies have shown that Zophobas atratus worms — the larvae of the darkling beetle commonly sold as pet food and known as “superworms” for their nutritional value — can survive on a diet of plastic, because its gut contains bacteria capable of breaking down common types of plastic. However, their use in plastics processing has been impractical due to the slow rate of feeding and worm maintenance.

NTU scientists have now demonstrated a way to overcome these challenges by isolating the worm’s gut bacteria and using them to do the job without the need for large-scale worm breeding.

In the study, published in Environment International, the NTU scientists fed three groups of superworms different plastic diets — high-density polyethylene, polypropylene and polystyrene — over 30 days. The control group was fed a diet of oatmeal. After feeding the worms plastic, scientists extracted the microbiomes from their gut and incubated them in flasks containing synthetic nutrients and different types of plastics, forming an artificial “worm gut.” ❐