Grenzebach lifts the lid on its Ultra High-Efficiency Dryer for gypsum wallboard, which combines proven technology with a revolutionary configuration...
Global Gypsum (GG): What led Grenzebach to develop the Ultra High-Efficiency Dryer?
Robert Brier (RB): Grenzebach is a technological leader in the global gypsum sector that is always questioning the status quo and looking for ways to improve. Besides aiming to be price-competitive, we can leverage our strong engineering expertise to push the development of the sector further than ever before, to bring new benefits to our clients. At the same time, the sustainability of operations, particularly the reduction of CO2 emissions, is an increasingly important priority for wallboard producers worldwide.
The patented Ultra High-Efficiency Dryer is a response to these drivers, as we wanted to focus our developments on the most energy-intensive part of the plant. The new design can help producers to meet their sustainability goals, while saving costs.
GG: Is the Ultra High-Efficiency Dryer an evolution or a revolution?
RB: It is both. On the technical side, it is an evolution, as we have only used proven technologies from across our dryer range. We are still blowing hot air onto boards to evaporate water. However, the configuration of those proven components is quite revolutionary. We have fundamentally changed the way that wallboard is dried, including the temperature regime, number of decks and how we utilise energy around the system.
GG: How does it differ from a conventional dryer?
Dennis Schattauer (DS): The fundamental aim behind the Ultra High-Efficiency Dryer is to reduce the energy used, while still evaporating the same volume of water. We have made two main alterations to do this. The first is to increase the residence time. So that we can keep the same line-speed before the dryer, we have multiplied the number of decks inside after the initial high-temperature zone. Increasing the residence time allows us to decrease the temperature in the remaining zones, allowing us to use less natural gas. Meanwhile, the hot gas from the high-temperature zone is also redirected to the low-temperature zones, further reducing gas use and associated CO2 emissions.
GG: How significant will the CO2 savings be?
DS: We anticipate reductions of up to 30% for both CO2 emissions from the dryer and the cost of using natural gas, but this is just part of the story. Thanks to the heat exchangers in the energy recovery system, it will also be possible for wallboard producers to recover up to 50% of the water used in the slurry. This is a big deal in water-scarce regions.
GG: What changes will have to be made to the plant to use an Ultra High-Efficiency Dryer?
RB: The Ultra High-Efficiency Dryer is intended as a 1:1 replacement for existing technology, with entry and exit speeds maintained. It is slightly longer and taller than a conventional dryer. It will easily fit into most wallboard plants, but adjustments can be made, for example repositioning ducting and heat exchangers, in the unlikely event that sufficient space is unavailable. This may reduce the efficiency gains, but they would still be around 20%.
GG: How will the up-front cost compare?
RB: We can't pretend that an Ultra High-Efficiency Dryer will cost the same as a conventional one. There's going to be a premium. However, the gains to be had in terms of reduced natural gas spending are soon recouped. The additional cost of installing the new design compared to a conventional one will be less than three years in most cases, sometimes even less.
GG: How will a similar size dryer cope with three times as much wallboard inside? Are there not three times as many things that can go wrong?
DS: On the face of it, there appears to be more that could go wrong, because there are more moving parts. This includes the elevators that we use to separate the boards into the higher number of decks. However, the equipment is moving at a much lower speed. Simultaneously, the lower temperature means that wallboards are not at risk of over-calcination on the edges. Due to this, we can run them with small gaps between them, greatly reducing the potential for boards to jam in the dryer.
GG: What stage has development reached so far?
DS: We have modelled the complete dryer and are currently building full-scale test sections at our workshop in Bad Hersfeld. We have three sections and are focused on the low-temperature sections most keenly, as this is where the biggest innovations are. Next, we will simulate the distribution of the boards in the low temperature decks, which have been multiplied in number. The elevators used are a proven technology in our wallboard dryer range.
GG: Which types of wallboard producer do you think will be most interested, at least initially?
RB: We are interested to work with any wallboard producer that is committed to reaching its climate targets. Several of the larger ones have committed to reducing their CO2 emissions by 40% by 2035. This is not a target that can be reached by tweaking existing processes. It needs major steps.
I am delighted to say that, following just the initial modelling demonstration, one client has already ordered two Ultra High-Efficiency Dryers. They are scheduled for installation by the end of 2024. This shows its high level of confidence in our new approach.
GG: Which world regions is the Ultra High-Efficiency Dryer best suited for?
DS: The 'cop out' answer is 'everywhere,' but we expect the most enthusiastic operators, at least at first, to come from markets where natural gas prices are the highest. Water-stressed markets with 'almost free' gas are also important for this technology, thanks to its potential to halve water consumption. For many, this will be the most important factor.
GG: What comes next for Grenzebach after the Ultra High-Efficiency Dryer?
RB: The Ultra High-Efficiency Dryer is the first step towards a new technological approach that we envisage for wallboard production. The crux is that, by reducing overall energy needs, we can start to talk about using lower-grade heat sources so that we can do away with the need for natural gas to be used in the dryer entirely. Low-temperature heat options include electrically-derived heat from renewable electricity sources, heat pumps, biomass boilers and other waste-derived fuels, as well as various combinations of these.
In the coming years, our new approaches will open up different options for producers around the world, with flexibility the key. Our understanding of how a wallboard plant functions will change enormously. It's an exciting technological journey and one that is starting right now!
GG: Thank you for an interesting discussion. We look forward to following your developments.
RB/DS: You are very welcome!
Robert Brier
Robert Brier has been chief executive officer of Grenzebach, based in Bad Hersfeld, Germany, since March 2022. He joined Grenzebach in 2002, having previously worked for Babcock BSH. He has held numerous roles in sales, project management and operations, both in Germany and the US.
Dennis Schattauer
Dennis Schattauer has been Grenzebach's Sales Director for Building Materials since August 2023. He joined the company's gypsum department in 2022, having previously worked in its glass division and CNUD EFCO, which was acquired by Grenzebach in 2019.
