PAPRICAN’S NEW PILOT PAPER MACHINE
By Pulp & Paper Canada
The development of a new process, a new pulp and paper grade or just a new manufacturing procedure usually starts with handsheets or laboratory-scale equipment. A successful product must eventually be...
By Pulp & Paper Canada
The development of a new process, a new pulp and paper grade or just a new manufacturing procedure usually starts with handsheets or laboratory-scale equipment. A successful product must eventually be introduced on a commercial scale. Such a scale-up could be very expensive, as the cost of lost production on a new paper machine is in tens of thousands of dollars. A pilot paper machine, which resembles a commercial machine in its speed and the mode of operation, might significantly reduce the scale-up cost of papermaking R&D.
Paprican’s fist pilot paper machine was built in 1965, primarily as the tool for development, demonstration and marketing or Papriformer. With the speed of 1200 metres per minute (m/min), it was the fastest machine in Canada. Following the successful commercialization of twin-forming, many significant developments were achieved using this machine for other projects. The developments include: initial trials on hot pressing, closure of open draws in the press section, impulse drying and development of a press fabric permeability tester. However, after 33 years of successful operation the machine was no longer able to meet the demands of new papermaking projects.
Paprican’s new pilot paper machine was built in 1999 and started up in 2000. The entire machine was designed for high flexibility and easy modification to meet the needs of R&D projects or commercial trials. The machine runs smoothly at 2500 m/min, although a second headbox will be required for papermaking at this speed.
The forming section contains an hydraulic headbox that can be rotated around the axis of the forming roll to modify the extent of water removal on the roll. Thus the former can operate as a roll former, a blade former or a combination of roll and blade former. With the slice width of 0.56 m the machine will be able to produce a sheet that is 0.36 m wide.
The press section consists of a four-roll three-nip press followed by a shoe press as a fourth option. The drives of the press section are arranged in such a manner that the machine can operate with all but the second press nip open. By setting the appropriate combination of press nips the machine can simulate the press section of many commercial machines. The sheet is transferred between presses and from the fourth press to the press section using the web transfer system developed at Paprican. The machine has no open draws.
The dryer section of the machine consists of just two High-Intensity Dryers (HID), a novel technology developed at Paprican. Since the drying rate achieved on HID is an order of magnitude greater that that of a conventional dryer, with two units, the new machine will be able to dry newsprint sheet at 800 to 900 m/min, while at higher speeds the sheet will be only partially dried. There will be no CD shrinking during drying, as the paper is restrained. Results obtained on the smaller prototype self-standing dryer indicate that an HID sheet is stronger and has a better print quality than conventionally dried paper.
Among the unique features of Paprican’s pilot paper machine is its stock preparation system, which is designed for whitewater closure. The sophisticated chemical preparation and addition system makes this pilot machine particularly suitable for various wet end chemistry trials under operating conditions ranging from open to fully-closed whitewater systems. The integrated control system, that includes drive motor control as well as data acquisition, uses FIX Intellution software and an Ethernet link to provide single-window access to all information. A computer model of the machine’s whitewater system, written using CADSYM and PAPDYN, can assist with machine trials especially those aimed at wet end chemistry and system closure.
The new machine will be used for further development and demonstration on HID, projects on system closure, sheet forming, and others. The machine is also available on a contract basis to paper mills and industry suppliers for confidential trials.