Energy-saving vacuum system rebuilds

In the papermaking process, providing vacuum is an essential requirement. Still, producing vacuum is always a complex and cost-intensive process. The cost of energy used by a vacuum system over its lifetime exceeds its purchase price many times over. Vacuum system optimization projects provide a very efficient way to reach both cost reduction and sustainability targets.

author: Runtech Systems

Industry Insight by:

Runtech Systems Oy

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

Vacuum system optimization and lower energy consumption start with the EP Turbo Blower. Completely water-free RunEco solution with Turbo Blowers is a fully adjustable, energy-efficient vacuum system for tissue production. It is a tailor-made solution equipped with optimal save-all and doctoring system and online dewatering measurements. RunEco can provide energy savings of 30 to 70%, and is applicable for both greenfield and rebuild projects. Mills have reported that vacuum system optimization with variable speed and capacity turbo blowers have saved them up to 2,000 kW. Together with Nash, another Ingersoll Rand brand, and the original innovators in liquid ring technology, we are the only company in the world that can supply both liquid ring pumps 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.

Hybrid vacuum system

A typical Runtech RunEco vacuum system consists of several smaller size turbo blowers giving clear design and operational advantages over the competition. 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 Liquid Ring Pump (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.

Engineered solutions for pulp and paper industry worldwide

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. Vacuum levels are measured at the vacuum pumps and blowers to identify problem areas. The dewatering elements such as flat boxes, save-all pans and uhle boxes are also reviewed. Specialists study pressure and bleed losses to analyze the energy consumption and evaluate if the vacuum levels are too high. In the following rebuild cases, existing liquid ring pump or pumps are compared to a hybrid system to find an optimal balance between investment and operating costs.

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 liquid ring pumps 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. As mentioned above, 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. In rebuild cases, an economical solution, with suitable airflows, can also be a hybrid vacuum system combining existing LRP with a new turbo blower. The LRP is continued to use for the higher vacuum uhle boxes and/or to assist the turbo blower with higher airflows after a felt change. In a case where the uhle boxes can be operated with moderate vacuum levels, close to the suction press roll vacuum, the LRP can of then be stopped during normal running period and used only for abnormal airflows such as experienced with new felts.

With the experience of thousands of vacuum system audits and dewatering studies at paper mills, we are able to benchmark the effectiveness of existing vacuum systems, dewatering equipment, suction elements, fabrics and felts. All information comes together in an often step-by-step rebuild or upgrade plan that results in minimized operational expenses coupled with a production increase and/or runnability improvements. Today, over 950 Turbo Blowers have been sold globally. 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.

Our main target is to bring notable energy savings and highly improved process efficiency


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