A tool for Evaluation of the Kraft Pulp Process.

PulpMac is a number of libraries which together with FlowMac blocks describe the Kraft Pulping Process. You can get a feeling about it by running a screening demo (mp4) or a screen demo(swf) depending on your computer. Another demo  for Continous Digester.

A sophisticated demo for AZP Bleaching of Pulp.


Pulp Mac AB (Bengt Nilsson) has developed modeling of the Kraft Process since 1990. First directly in Extend (Korsnäs, Tofte) and later on in FlowMac when it became available.


PulpMac is a knowledge based system to be used by the kraft pulping industry in engineering and evaluation of mill performance. Process modeling for decision support is the main idea. The system is modular based with a graphical interface and made for modeling of kraft pulping. It is, compared to other modeling tools, much easier to use. Besides mass balances it includes accumulation of process knowledge, estimate of production costs and even some kraft fiber properties.

PulpMac allows detailed modeling of the kraft pulp process for mass balances, dynamic simulation and the accumulation of process information. All the information contained in a PulpMac model including the flowsheet is saved in a single computer file which is easily transferrable by e-mail or hardware to suppliers or other offices, etc.

Making a model in PulpMac.

PulpMac contains five libraries – Digester, Screening&washing, Bleaching, Evaporation&Rec.boiler and Caustization - with 180 blocks. There are also twelve tutorial models in PulpMac to be used for training in use of the system and understanding of important processes. One of the models describes the whole kraft pulping process (except dryer which is taken from FlowMac if wanted).

Models are constructed in PulpMac by connecting process unit blocks to a flowsheet on the computer screen. The blocks can be designed according to the specifications made by the mill. The resulting model on the computer screen looks much like the process flowsheet familiar to process operators. The flowsheet can be printed in color.

Hardware requirements.

PulpMac is used together with FlowMac and have the same requirements.

Graphical Interface.

PulpMac presents balances on a computer screen and prints a flowsheet in color with important data animated close to each process unit. A section of a PulpMac flowsheet for a part of the screening department is given below.

The flowsheet demonstrates a cascade screening system. The model is constructed from a number of screening blocks from PulpMac and the rest is FlowMac. The screening process is based on the Q & T theory.

Each block contains a dialog for data input, selection of run setup and presentation of important information like screening efficiency, type of screen, pulp consistency,etc. The dialog can be viewed and data changed while a simulation is active.

Simulation using PulpMac.

During a simulation, flows of water, fiber, COD, steam, condensate and temperature and so far up to 60 tracers are transferred between blocks. Summaries of operation costs and energy consumption are included - if needed. Flows are iterated until a balance is achieved. A simulation can be paused to modify process parameters for sensitivity analysis. Sliders allow continuous changes of important parameters, such as reject degree or kappa number.

Time lags in chests, pipes and paper machine sections are included into dynamic simulations. Dynamic retention can be simulated.

Any data collected during a simulation can be transferred to ACSII files or to a spreadsheet (Excel, open Office, etc) for further analysis. A notebook for selected data can be made. Plotters illustrates flow or concentrations of selected process parameters.

User Friendly Software.

PulpMac and FlowMac are simple to use. After only a few hours of training, normally on the web, the user can design models of the kraft production process. The results of course are depending on the input values and that certainly need some kraft pulping skills.

PulpMac is supplied to a customer including training and the modeling of a selected production process.

Some PulpMac Applications:

  • Preengineering of a Process, New or Rebuilds

  • Modeling of the Complete kraft mill including Fiber, Water, Chemical and COD balances

  • Modeling of the Mill Energy Situation (Steam, Warm Water, Electricity)

  • Training of Operators

  • Trouble Shooting

  • Simulation of Control Strategies in Buffer Chests and Mill Unbalance (production increase)

  • Knowledge Data Base for a Process Unit

  • Calibration of process instruments by use of a flow balance

  • Modeling the economy of a product. Mass balance of money!

  • Modeling of “closed” water systems

Latest news

Support and Upgrade of FlowMac

In the mid of 2014 I will close my and papermac AB:s responsibility for supply, upgrade and support of FlowMac. The reason is age and a very ... [Read more]

So far tests has shown that FlowMac can be operated by Extnedsim9. Models having up to 75 blocks can be rebuilt in Extendsim9LT.

[Read more]

Linerboard machine model
A Linerboard machine model used for production increase is now available in FlowMac. It is produced by the most experienced user of FlowMac.

An upgraded version of Extendsim is on the way. It has many promising new functions. Papermac will test it and upgrade FlowMac.

[Read more]

Windows 8
Tested by one experienced customer. Extend6 runs without problem

Last edited: 2013-01-21 04:18

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