Luca Linari: The PrimeDry HotAir Box is an innovation from ANDRITZ that focuses on utilizing exhaust heat to enhance energy efficiency and reduce carbon dioxide emissions in tissue-making processes.
ANDRITZ PrimeDry HotAir Box Close up
Luca Linari: Energy efficiency is crucial for sustainability and competitiveness in tissue production due to factors such as tough company commitments on CO₂ footprint reduction, taxes on emissions and rising energy costs. Never have marginal differences in energy consumption been so significant for sustainability and competitiveness and in tissue production. The motivation to maximize energy efficiency and reduce carbon dioxide emissions is therefore high and rising. With this in mind, ANDRITZ is determined to leave no stone unturned in its quest to minimize the energy input required to manufacture tissue.
Luca Linari: It addresses the limitations of drying capacity and machine speed in tissue. All technologies can encounter roadblocks to progress, and in tissue production, the viscosity of water itself has historically restricted water removal by the suction roll. This means that either drying capacity or machine speed limits most tissue machines. ANDRITZ has addressed both these limitations with its new PrimeDry HotAir Box technology for Dry Crepe tissue machines, for new machines or upgrades.
Luca Linari: PrimeDry HotAir Box channels part of the hood exhaust flow, which follows the air-to-air recovery exchanger and blows this air directly and evenly across the paper web just before the suction roll. This has the effect of raising the temperature of the paper web. Therefore, the viscosity of the water in the paper web is reduced, which leads to increased dryness after the press.
ANDRITZ PrimeDry HotAir Box: Highlighted air systems
Luca Linari: The effect is most significant in the world’s many single press applications, where the technology can increase post-press dryness significantly, and consequently give a remarkable increase in speed with the same drying load or a reduction in energy required for a given drying capacity. For this reason, PrimeDry HotAir Box is particularly suitable for rebuilds of single press machines, for which the return on investment can be exceptionally quick, particularly with high energy prices.
Luca Linari: Yes, double press and shoe press configurations can also benefit appreciably from reduced energy consumption or higher speed for an unchanged energy input. The common factor is that higher performance or energy savings are the two possible outcomes from investing in PrimeDry HotAir Box.
Luca Linari: Variable factors such as grammage, energy costs and machine configuration will determine the difference which PrimeDry HotAir Box can make. In parts of the world where tissue paper grammage is typically lower, speed is unlikely to be a limiting factor because it is probable that the mill is operating its machines at their design speed limit. In this case PrimeDry HotAir Box offers energy-saving potential for an unchanged tissue output. On the other hand, in regions where grammages are typically higher, there is likely to be scope for raising machine speed to increase output without increasing energy consumption, although energy saving at the same speed is the other option. This is why PrimeDry HotAir Box is such a relevant innovation: it has the potential to bring benefits in such a diversity of tissue-making scenarios.
ANDRITZ PrimeDry HotAir Box with air systems
Luca Linari: The scope includes a stainless-steel flow box with a pneumatic retraction system, an air filter on the duct line, three automatic dampers, a centrifugal fan, and instrumentation. The pneumatic retraction system moves the box and leaves space for safe and easy maintenance, tail threading operations and cleaning. The instrumentation for temperature, moisture and other variables is provided to enable control of the system ANDRITZ supplies the logic and an I/O list to be implemented by the paper mill on the machine’s DCS, or within ANDRITZ’s own logic system if it is a new tissue machine.
Luca Linari: The first two installations have taken place in Europe and the Americas both mainly for energy saving. In the first, for example, the PrimeDry HotAir Box is installed alongside a yankee-hood rebuild project aimed at energy reduction. This is an application where, for a relatively small additional investment, the client can significantly increase the benefits of the rebuild. It is straightforward to add this technology as a retrofit on a machine of any age, either as part of a rebuild or as a stand-alone upgrade. The same goes for new machines where PrimeDry HotAir Box brings the marginal gains which increase sustainability and competitiveness. From this perspective, to further maximize its benefits, the PrimeDry HotAir Box can be combined with other ANDRITZ applications, such as the Prime Dry YES (Yankee Eco Steam System), which is used to generate high and low pressure steam to feed the Yankee or other equipment.
Luca Linari: ANDRITZ is one of the technology leaders, a proven partner to the global tissue industry, and has decades of experience. The PrimeDry HotAir Box is a perfect example of its comprehensive competence, from individual components and rebuilds to complete PrimeLine tissue machines. Saving resources is the common theme throughout our portfolio and with PrimeDry HotAir Box we have set the benchmark even higher and are constantly working on future generations of this and other technologies to improve outcomes for customers.
