In November 2020 Maarten Schutyser, chair of NWGD (Netherlands Working Group Drying), welcomed over 90 people from all over the world to the online NWGD symposium with the theme: “Drying in challenging times”.
In the first block Juray de Wilde from Université Catholique de Louvain (France) talked about vortex chamber technology and Eoin Murphy from Teagasc (Ireland) about VOMM continuous dryer.
In the second block five short presentation of companies followed. Floris Schoenmakers from Futurekitchens (Netherlands) and Paul van der Weide from Cosun (Netherlands) presented powdered soups from vegetable surplus as well as protein transition in the context of drying. Mathias Trojosky from Allgaier (Germany) and Hein Weijdema from Cevap (Netherlands) presented their technologies namely an innovative contact disk dryer and an inexpensive multi-effect distillation principle. Finally, Meishan Guo from Surface Measurement Systems (United Kingdom) gave insight into the impact of drying conditions of material stability.
In the third block Jeremie Bardo from Riera Nadeu (Spain) talked about their flash and spray drying technologies. Jamal Yagoobi from the Worcester Polytechnic Institute (USA) introduced the Center for Advanced Research in Drying. The last presentation was given by Varsha Pida from Albemarle (Netherlands) on the support of catalyst during drying.
Intensified spray drying using vortex chamber technology and radial multi-zone operation
Juray De Wilde – UCLouvain
Drawbacks of conventional spray drying are a poor heat transfer between air and droplets, the big size and therefore high energy requirements as well as limited velocity. To overcome these disadvantages Juray de Wilde and his team investigated a vortex chamber dryer and improved it towards a radial multi-zone dryer. The advantages of this dryer are the high efficiency and energy savings, the compactness and low investment costs as well as the good product separation and the premium product quality.
The vortex chamber technology consists of a static geometry in which the drying air is tangentially injected. It combines a high-G intensified gas-droplet contact, separation and particle segregation. To be able to intensify spray drying with this method, multi-zone operation is necessary. This leads to the axial multi-zone dryer (AMD) where the liquid product is sprayed through the cylindrical wall into the hot zone in the middle, moves towards the wall into the colder zone and is collected at the wall. However, the axial motions of the nozzle spray were stronger than the simulations predicted. Therefore, the powder was burnt as there were no distinct high and low-temperature zones.
The researchers changed the system to a radial multi-zone dryer (RMD) where the liquid is sprayed through a central nozzle in co/counter current with hot air injection. This leads to distinct hot and cold zones, whereas the initial drying takes place in the hot zone and final drying in the cold zone. Due to the rapid evacuation of the particles to the cold periphery, the hot and cold air are used efficiently, and high product quality can be obtained.
VOMM Continuous dryer for whey
Eoin Murphy – Teagasc
The Irish Agriculture and Food Development Authority called ‘Teagasc’ and the Irish diary industry are expanding their pilot plant facility Moorepark Technology Ltd. During the expansion, a continuous dryer developed by the Italian company VOMM and France’s National Research Institute for Agriculture, Food and Environment (INRAE) is being installed. The VOMM continuous dryer can be used to dry permeate and whey streams, consuming less energy than conventional spray drying methods.
When liquid whey and permeate are dried using the conventional method, they are first concentrated from 6% to 60% dry matter, then crystallized and spray dried to 97% dry matter. The spray drying step uses much more energy than the concentrating step, but concentration was only done until 60% since after this point the viscosity became too high. The VOMM continuous dryer uses the innovative Poudre Sans Tour (PST) process. This process is based on an agitated thin-film evaporator where viscosity is controlled by a vigorous mechanical treatment that maintains a fluid state at a high dry matter content. Using this technique, the feed can be superconcentrated to 80% DM and subsequently wet granulated to 88% DM before final drying, which strongly cuts the energy consumption of the process.
From vegetable surplus to premium powder ingredient
Floris Schoenmakers – Futurekitchens
In the beginning of 2020 Futurekitchens was founded by Floris Schoenmakers and Jef Cavens. They set-up a production and are selling powdered vegetable soup since then. It is supposed to be a healthy snack with a lot of vegetables from overproduction. Futurekitchens, which is certified by the B Corporation, wants to connect the sustainable development goals with a top product. Therefore, overproduction is used, which often ends up as a land fill and produces methane, which roughly contributes 8% to global warming. The start-up buys overproduction from farmers, processes these products to mash, which is then dried in a freeze dryer and pulverized. These single pulverized ingredients including herbs are mixed to form the final product and are filled into a single use package made of sugarcane. The first sustainable package material, called “earth film”, led to leaking seals. For now the only product is soup, but with the same process other products like smoothies or baby food can be produced, as the ingredients are stored separately. Regarding sustainability in processing, freeze drying consumes a lot of energy and alternatives for it are still in consideration like refractance window drying.
Protein transition at Cosun in the context of drying
Paul van der Weide – Cosun
The agro-industrial cooperation Cosun is looking for ways to optimally use the plants they are growing. One of the opportunities they saw was making better use of proteins, since plant proteins are a fast growing market. For this reason, Cosun established their corporate protein strategy, with the goal to develop a significant protein business by obtaining a sustainable, competitive position in the protein market.
An example of this project is the extraction of the RuBisCO protein from sugar beets. The leaves of the beet plants contain small amounts of the RuBisCO protein, which can be extracted and used as a valuable functional protein, for example for meat substitutes and bakery products. Aside from the low yield, there are some other challenges when it comes to processing the RuBisCO protein. It is thermosensitive, so concentration and drying have to be done at low temperatures, and thus it is more difficult to control the microbiology.
Together with the HAS, BioscienZ and The Protein Brewery, Cosun launched the Green Protein Excellence Center (GPEC). This is an open innovation platform to support development of proteins from agro-industrial raw materials and coproducts for food and feed applications.
Innovative contact disc dryer CDry
Mathias Trojosky – Allgaier Process Technology GmbH
Allgaier Process Technology developed the CDry, an innovative way of a contact disc dryer for suspensions and solutions. The functional principle of the CDry is based on discs that are steam heated from inside. The product is applied on both sides of the surface of the discs and after a product-specific turn-around the dried product is scraped off the disk. Suitable products are for example brewery waste water, pigment, polymer, algea, milk and enzymes. It is possible to conduct customer trials at the test machine in the technical center in Uhingen or to use a mobile CDry for tests directly at customer sites.
The CDry has many advantages. It consumes up to 50 % less thermal energy than convective dryers and its capacity can be up to 60% higher than other compact dryers with a small footprint while minimizing processing costs. In addition, the CDry is customizable concerning number of discs, diameter, material and coating of the discs and it has an automatic cleaning system for easy material and production change. The current development project “CDry Fit for Food” aims to revise the disc dryer to meet (hygiene) requirements of the food industry, which will be presented at ANUGA FoodTec 2021. Another project is CDry inductive, which is an innovative dryer option using induction heating instead of steam heating.
Cevap technology based on Multi-Effect Distillation principle
Hein Weijdema – Cevap Technology BV
CEVAP Technology B.V. was started five years ago by Heijn Weijdema to fill a gap in the water treatment market. Methods to treat small volumes of water used to be expensive, and cheaper methods were only available for large volumes. With the equipment made by CEVAP, also small volumes of water can be treated in a cost-effective way. The new technology is based on the existing vacuum multi-effect distillation (VMED) principle, which is used to make clean water vapour out of dirty water. The problem with the current evaporation equipment is that maintenance and cleaning is difficult and expensive, and that it is made of stainless steel being sensitive to corrosion and very expensive.
The CEVAP equipment is made of plastic, which is not sensitive to corrosion. Inside the plastic vessels, disposable cartridges with thin plastic foils are placed. When these cartridges are contaminated, no expensive cleaning or maintenance has to be done since they can simply be removed.
Impact of drying conditions on stability of food and pharmaceutical materials
Meishan Guo – Surface Measurement Systems
With the DVS, Dynamic gravimetric Vapour Sorption method, of Surface Measurement Systems (SMS), solids can be characterized via the absorption and adsorption of molecules of the sample. It is a fully automated instrument, which reaches equilibrium fast and is a pioneer in vapour sorption technology. The gravimetric data reveal moisture-induced phase transition points like caking or deliquescence and glass transition similar to DSC (Dynamic scanning calorimetry) ramps. This system can measure in a wide range of temperatures, pressures and vapours. It is a very sensitive technique to investigate various physicochemical properties and for example protein-sugar interactions. DVS can characterize crystalline and disordered materials like polymorphs and amorphous materials.
SMS conducted a study on Bovine Serum Albumin (BSA) mixed with maltose and sucrose and its impact on moisture-induced phase transitions. It was shown that the relative humidity (RH) of the glass transition did not change significantly with increasing BSA content. However, the crystallization point was shifting towards higher RH with increasing BSA. This indicates that BSA acts as a stabilizer. For the sucrose-BSA mixtures different freeze-dry conditions were tested, which showed that with the DVS method it is possible to study the stability under different conditions.
New flash dryer & spray drying technologies
Jeremie Bardo – Riera Nadeu/WinProcess
In order to save space, the Spanish industrial equipment manufacturer Riera Nadeu proposes to use a flash dryer instead of their spray drying tower. A flash dryer is based on a similar principle as a spray dryer, but the product has a much smaller residence time, allowing for a more compact drying chamber. Riera Nadeu developed a drying chamber with a closed loop system. With this system, the dry particles will leave the drying chamber together with the steam, whereas the particles which are not fully dried yet, will recirculate until they are dried as well. The flash dryer can be equipped with a spray nozzle or a wet-solid feeding system, so both liquid feeds and wet-solids can be dried, making it more versatile than a traditional spray dryer.
These flash dryers have been developed several decades ago to dry pigments and ceramics. Currently, also pharmaceuticals and food products can be dried using this flash dryer.
Center for Advanced Research in Drying (CARD)
Jamal Yagoobi – Worcester Polytechnic Institute (WPI)
The director of CARD, Jamal Yagoobi, introduced the Centre for Advanced Research in Drying, which was established as an US National Science Foundation (NSF) Industry University Cooperative Research Centre (IUCRC) in 2016. It is located at the WPI as well as at the University of Illinois (UIUC) with ten faculty members from each institute. The CARD focuses on conserving energy and becoming more
sustainable within drying processes, as drying has a high impact and accounts for ca. 20% of all process energy use in American manufacturing. Furthermore CARD, wants to reduce costs of drying, improve product quality as well as throughput and train the next generation of professionals.
In total 21 projects have been funded since 2017. This year ten projects are running, e.g. ultrasonic drying of bio-polymers and vegetable proteins, novel nozzle design for fine powders and enhanced heat and mass transfer and smart drying with machine learning. One project is about novel energy-efficient drying technologies focusing on di-electrophoresis, ultrasonic and slot jet reattachment nozzles to achieve up to 25% energy efficiency. The best performing technologies will be scaled up and advanced sensors and AI shall be integrated for optimal process control. First results are a smart drying unit, which includes conductive, ultrasound, radiative and convective drying methods to reduce energy consumption as much as possible.
Finally, Jamal Yagoobi invited to the next semi-annual meeting in May 2021 and the 22nd International drying symposium in June 2021 (27.6. – 30.6.2021) at WPI campus.
Catalyst support drying – Towards future applications
Varsha Paida – Albemarle Catalysts BV
Albemarle is a large chemical manufacturing company with several divisions, of which one is the Albemarle Catalysts Division. In Amsterdam they have a site which produces various types of catalyst, for example hydro processing catalysts (HPC). In the production line of HPCs, several drying steps are needed which need a lot of energy. According to the EU regulations, the Amsterdam site needs a 50% reduction in CO2 emissions by 2030, so Albemarle is looking for opportunities to reduce their energy consumption and CO2 footprint. Currently, 90% of the energy used on site is by natural gas and 10% by electricity. One method which could be effective is by optimizing the current production methods, making them more energy efficient and consequentially reducing the gas consumption. Another method is replacing natural gas with a more environmentally friendly energy source, like electricity, hydrogen or renewable energy sources.