Towards energy-efficient and economical tissue production with RunEco solution

Vacuum demand varies for different paper grades, felts and machine speeds, therefore, a tailor-made solution with flexible and variable capacity can balance the supply and demand, resulting in both optimized dewatering and minimized power consumption.

author: Runtech Systems

Industry Insight by:

Runtech Systems Oy

A one stop shop to all paper machine dewatering solutions and services

Together with Nash, another Ingersoll Rand brand, we are the only company that can supply both liquid ring pumps (LRP) and dry vacuum systems, or a combination of them, for a so-called hybrid system. In addition we offer doctors and save-alls, making our offering complete for paper machine dewatering. With this unique portfolio, we can always find a perfect fit for our customer’s demands, needs and budget.

RunEco vacuum system is developed especially to take into account the challenges and demands related to the dewatering and runnability. Traditional method of increasing vacuum levels is replaced with speed adjustable turbo blowers, optimal doctoring and save-all systems with online dewatering measurements. By using only the needed vacuum in the critical consumers, mills can fully benefit from the more efficient nip dewatering strategy and save energy. Depending on machine design and width the most efficient operation sometimes requires one and sometimes two turbo blowers. The specified air flow capacity is typically quite high consisting of overall safety margin, felt life and type margin and with LRPs e.g. pump wear and seal water temperature variation margins. In normal operating conditions the needed air flow capacity is ~40-50% lower than the specified capacity. Regardless of the situation, RunEco system with a fully speed-controlled turbo blower provides high operating efficiency at all times.

Your reliable partner, whenever you are looking for solutions to improve runnability and efficiency

During normal operation one single-stage turbo blower typically provides sufficient capacity. However, a system with two units allows even higher operational flexibility, controllability and energy efficiency. E.g. often tissue machines have three main vacuum consumers, namely the press suction roll and two felt Uhle boxes. Also often the vacuum level of the suction press roll is clearly lower than that of the Uhle boxes. And as air is a compressible medium the volume changes significantly with the surrounding pressure. These unavoidable facts lead to considerable energy losses in a one-unit system through two mechanisms.

First being the throttling losses in the suction press vacuum level control and, second the loss due to the air expansion from the lower suction press roll vacuum state to the higher vacuum in the felt Uhle boxes and in the main vacuum header. An often used vacuum level difference of approx. 10 kPa between the suction press roll and felt Uhle boxes can lead to over 30% increase in the air volume through expansion and thus naturally to large increase in the energy consumption. A two turbo blower RunEco system, while offering a redundant air flow capacity, offers additionally a higher degree of controllability and less losses resulting in a more energy efficient vacuum system.

Typical savings in energy consumption are 30-50% when the losses are eliminated in a two turbo system. In addition we also offer LRP technology to form a combination of both technologies – namely a hybrid system.

A tissue producer gained energy savings of 447 kW which was almost 50% of its previous usage; water usage decreased by 75%. The installed EcoFlow dewatering measurement system provided a better control of the process
A confidential tissue producer kept two LRPs for the chester box.
A RunEco EP550-T1 Turbo Blower was connected to other vacuum consumers to allow for all energy efficiency targets to be reached

Hybrid vacuum system

Quite often a situation has been observed where a single, or a few low air flow consumers (devices) are operating at high vacuum levels, such as a high vac box or a press suction roll high vacuum zone, while the rest use a considerably lower vacuum level. This leads to a situation where the most economical option is to continue the use of the existing LRP. Fully rebuilding a system with blower technology is not always the most efficient solution, especially if this means that different vacuum levels need to be combined in one blower. It is proven that a well maintained LRP operating at low speed to produce high vacuum level can perform at a good efficiency level outperforming systems where a large single blower experiences considerable expansion losses.

Discover the potential of your machine

With the experience of thousands of audits and studies at paper mills, we are able to benchmark the effectiveness of existing vacuum systems, dewatering equipment, suction elements, fabrics and felts. This experience and expertise allows us to work with our customers, help them get the most out of their papermaking process and vacuum systems – and ensure they achieve both their operational and process goals.

Another fundamental issue in an energy efficient vacuum system is dewatering and doctoring. These are not only related to energy consumption, but also play a major role in paper machine runnability (profiles), efficiency (dirt and breaks) and profitability. Therefore, a well-designed and operated dewatering and doctoring system is one of the key issues to a well-performing and energy-efficient machine



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