Vacuum Blower Saves 40-50 Percent Tissue Dewatering Costs

Increasing energy costs and environmental/sustainability issue are driving factors

Customers in the tissue and paper industry are increasingly retrofitting their production plants with TURBAIR® blowers, according to Germany-based MAN Diesel & Turbo. Rising energy prices and growing environmental awareness are behind a boom in sales of vacuum systems developed and constructed by MAN Diesel & Turbo at its Zurich, Switzerland, plant. Tissue and paper manufacturers appreciate the numerous benefits of blower technology compared with traditional vacuum generation using water ring pumps, the company reports.

The TURBAIR vacuum system is used for many new installations of tissue, paperboard, and paper machines. At the same time, there is a strong trend toward conversion. The 200th TURBAIR type RT vacuum system left the MAN Diesel & Turbo factory in Zurich at the end of January. The vacuum system consists of two type RT 56 and RT 71 single-stage vacuum blowers, and will replace a total of 10 old water ring pumps for a South Korean customer.

The TURBAIR technology gives tissue, paper, and paperboard producers a huge competitive advantage compared with conventional vacuum systems. Our vacuum system not only makes a significant contribution to environmental protection, it also enables a massive reduction in production costs at the same time,” explained Manfred Dobler, head of Paper Industry at MAN Diesel & Turbo.

Vacuum systems play a central role in the paper production process. They are deployed at the point in the production process at which the installation dewaters the paper using vacuum. TURBAIR systems from MAN Diesel & Turbo handle volume flow rates of 180 up to 2,800 cubic meters/min.

RESOURCE-EFFICIENT,
COST-SAVING DEWATERING

The sustained success of TURBAIR is based on a number of factors:

Constructed using radial flow impellers, the vacuum blowers generally have an absorbed energy consumption that is up to 30 percent lower than conventional water ring pumps since there is no frictional loss caused by the water ring.

The TURBAIR blowers do not require seal water, so operators can save on fresh water.

Depending on the grammage, speed, and material composition of the type of tissue or paper to be produced, the paper machine needs different volumes of air and vacuum levels for optimum, cost-effective dewatering. The TURBAIR blower types have a wide working range so the blowers can also be efficiently operated under partial load. This leads to a further, up to 30 percent, reduction in energy consumption.

Another advantage is that MAN’s blowers have no wearing parts and are especially easy to service. Even older generation vacuum blowers installed by MAN more than 60 years ago are still working to the total satisfaction of numerous customers.

As well as the broad working range of the blower, frequency-controlled drives are increasingly being used. This allows not only the air volume, but also the vacuums to be adapted optimally to the conditions of the paper machine. This leads to a further, up to 20 percent, reduction in energy requirements.

In combination, these benefits result in a simple return-on-investment calculation for our customers. The amortization time of a TURBAIR system of this kind, installed in an existing tissue or paper production mill, is less than two years,” Dobler explains. Numerous conversion references evidence an energy saving of 45 to 65 percent of the absorbed power. This does not even take into consideration the additional savings from the use of a one- to three-stage heat exchanger.

WHEN IS WHICH
BLOWER TYPE USED?

One-stage RT blower with emission regulation: Depending on the size, an RT vacuum blower of 200 to 2,200 cubic meters/min. and up to 60 kPA can be used. Thanks to the automatic outlet regulation, the volume flow adapts flexibly to the relevant requirements of the paper machines. The controller automatically governs the volume requirement from 30 to 100 percent. At the same time, the RT with a frequency-controlled drive can set the vacuum between 35 and 60 kPa.

This large area of application makes the RT range perfect for felt conditioning, for tissue applications, and, most importantly, for replacing existing vacuum systems.

RC Type Vacuum Blower: Depending on the size, the RC type vacuum blower can be used from 180 to 2,800 cubic meters/min and up to 75 kPa. With its up to four intake manifolds, all vacuum levels can be operated on the filter and press section. At the same time, the blower with a frequency-controlled drive can set the vacuum between 55 and 75 kPa. It is chiefly in demand for new installations for graphic papers, paperboard, or chemical pulp. These require a high vacuum, which the RC type blower supplies reliably, thanks to its multi-stage centrifugal design. It can replace entire water ring pump systems. 

LEFT: TURBAIR vacuum blower type RT

ABOVE: Automatic output regulation

RIGHT: TURBAIR® vacuum blower type RC

The chart illustrates a few references where TURBAIR technology replaced a mill’s existing vacuum system:

System

Product

Absorbed power from existing vacuum system

Absorbed power from TURBAIR®

Saving

1

5.0 m wide

1120 m/min

SK paper

180 g/m2

2300 kW

1260 kW

45%

2

5.8 m wide

900 m/min

SC paper
120 g/m2

2100 kW

800 kW

62%

3

5.6 m wide

1200 m/min

Tissue

1070 kW

560 kW

48%

4

4.0 m wide

850 m/min

Kraftliner
180 g/m2

1900 kW

1100 kW

42%

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