Paper 360
As the effects of climate change become more evident, companies around the world are working to reduce their environmental impact. The tissue industry relies on many resources to manufacture its products, and energy crises, water scarcity, and the rising cost of raw materials are driving tissue producers to find new ways to contribute to environmental efforts while still remaining profitable.
To help tissue mills reduce their environmental footprint, there has been significant innovation in sustainable tissue technology. As a result, tissue makers have considerable opportunities to produce tissue more sustainably. There are multiple process technologies, automation solutions, and services that a mill can incorporate to lower energy consumption, reduce CO2 footprint, minimize water usage and optimize fiber mix.
Tissue mills with efficient technologies, optimized designs, and sustainable practices are best positioned to minimize their environmental footprint while maximizing production. Valmet Advantage hybrid technologies can produce premium-quality tissue at low energy and fiber consumption.
LOWER ENERGY CONSUMPTION
Energy consumption is the primary source of human-induced greenhouse gas emissions (GHGs). To reduce energy consumption and, in turn, GHGs, it’s important for tissue makers to consider how much energy production processes use, as well as what kinds of fuels they consume.
When designing or updating mills, a combination of process technologies, automation solutions, and project services can reduce energy consumption and make it possible to convert all or portions of power consumption from fossil fuels to renewable resources. With a full suite of solutions, it’s possible for a typical, full-size mill to reduce energy use by up to 495 kWh/ton and, in turn, reduce carbon emissions by 96-131 kg/ton when compared to a mill with older technology.
In drying processes, there are several technologies that use carbon-neutral energy sources, including CFB boilers and hot air generators, steam hoods with a large Yankee, hydrogen burners, and electric heaters. For instance, an electrical heated hood with a large Yankee can be powered by steam and electricity from renewable sources while maintaining a high production capacity. This combination can reduce energy by 47 kWh/ton and net carbon emissions close to zero kg/ton of produced paper.
To utilize the full potential of a mill, it is essential to have very good control of the process. This level of control requires industrial digital and automation solutions. These tools can collect and analyze large amounts of data to automatically make process corrections, as well as provide tissue producers with valuable insights that allow them to make immediate decisions based on actual mill conditions. This can help ensure that the process operates in the most optimum way every moment. Utilizing a production line’s full capability by minimizing waste and maximizing efficiency with the lowest possible specific consumption is positive from all sustainability aspects.
Through optimization, it’s possible to continuously improve mill performance over time, increasing efficiency, reducing downtime, and maximizing output. Key factors that can help enhance mill performance are:
Training and skill development: Offer regular training opportunities for operators and maintenance staff to learn to effectively operate and maintain equipment.
Process optimization: Analyze the process to identify and address bottlenecks and inefficiencies.
Energy auditing: Conduct an energy audit to identify opportunities to improve energy efficiency.
Technology investment: Research technological advancements and consider strategic investments in those that can enhance performance.
Benchmarking: Compare mill performance against industry benchmarks and identify areas for improvement.
Safety protocols: Regularly review and update safety protocols and training programs. Prioritizing safety can help protect personnel and production uptime.
Data analytics: Use data analytics to gather insights into performance trends. Implement predictive maintenance based on data analysis to prevent unplanned downtime.
The Advantage™ ViscoNip® press developed by Valmet is an important component in the tissuemaking process to improve mill energy efficiency.
MINIMIZE WATER USAGE
Many people across the world face water scarcity. To help ensure water security, it’s crucial that companies that use large amounts of water work toward reducing their water footprint. Water is essential for tissue mill processes, yet there are proven ways to minimize water consumption and improve wastewater quality over the long term while maintaining production efficiency.
Each mill’s water quality and process are different, and there are a number of factors that producers must consider to minimize consumption. However, there are many water-efficient solutions that tissue producers can choose to implement. These include:
- Counter-current wash principle, which concentrates fresh water use on processes near the final product and white water on earlier processes
- Good control of retention, which carries particles out of the system instead of settling within the system
- Minimum bacteria growth, which can be controlled through a carefully designed process and chemical program
- Balance between pulp and water tank volumes, which can prevent the need for additional water during process disturbances
- Kidney function, which controls and eliminates harmful substances from the process system
- Online feedback and control, which provide information about the process chemistry
It’s also important for mills to reuse water when possible, such as cooling water and recycling water from effluent treatment.
One solution that manages white water quality and freshwater usage is a combination of controls and a WEM analyzer. A comprehensive, compact analyzer can be integrated as part of the automation system and measures charge and key properties of the furnish.
Another tool is ultrafiltration of the white water. An ultrafilter can capture and reject many unwanted substances from the process, keeping freshwater consumption to a minimum. Both a WEM analyzer and an ultrafilter are suitable for retrofit or greenfield projects.
DIVERSIFY FIBER MIX
The raw material that tissue makers source to produce tissue can impact their carbon footprint. By using process technology that can diversify a mill’s fiber mix, tissue makers can reduce their environmental impact while maintaining attractive tissue properties.
Historically, tissue makers have predominantly sourced wood fibers, virgin fiber, or recycled fiber to make tissue. Yet, overuse of virgin wood fiber can result in deforestation, which can impact biodiversity and release additional CO2 into the atmosphere. Furthermore, the availability of recycled fibers varies. However, there are other fibers tissue makers can source that reduce carbon footprint and deforestation, as well as cost.
Annual fibers, made from plants such as bamboo, bagasse, and straw, are one of the biggest underutilized biobased raw materials in the world. Some of them are today treated as waste and burned in the fields after harvest. With similar properties to wood fiber, annual fibers can have a lower CO2 footprint than wood and can reduce deforestation.
There are technologies that allow tissue makers to save highly valuable fibers. Refiners can convert a diverse fiber mix into microfibrillated cellulose (MFC), a highly refined fiber with fines less than 0.2 mm in length that adds another dimension to how the fiber impacts the final paper properties. By reducing the need for wooden long fiber, MFC reduces a tissue maker’s carbon footprint and cost.
Hybrid tissue machine technologies make it possible to reduce the amount of fiber required to produce tissue products by producing a bulky product with fewer plies while maintaining or even improving softness. Hybrid machines have better fiber efficiency, which can result in nearly 30 percent more roll bulk and 10 percent better softness quality using 20 percent fewer fibers than conventional process technologies. By incorporating these machines, tissue makers can reduce basis weight for hybrid bath tissue products at higher caliper and comparable tensile levels.
JOIN THE GREEN JOURNEY
Although tackling climate change can feel daunting, the paper industry already has many of the solutions it needs to make a difference. There are many opportunities for tissue makers to join the green journey and empower eco-friendly tissue production at their mills.
With the right technologies and project services, it’s possible to design a mill that minimizes environmental footprint, including water consumption, CO2 emissions, and energy use. And by evaluating and diversifying the fiber mix used in tissue production, tissue makers can reduce their environmental impact while maintaining product quality. Through efficient technology, optimized mill design, and environmentally conscious practices, a more sustainable business and future is attainable today.
