With funding from ÅForsk, ÅF and VTT have co-operated in developing a new simulation architecture, where features of ChemSheet are used within CheMac, an Extend based program like FlowMac and KraftMac. The result is a new simulation tool that that will improve the performance of ÅF’s other Extend based simulation programs, FlowMac and KraftMac.
2 Aims of the project
The purpose of this R&D project was to develop a new simulation tool, in which pH and solubility of a number of key substances in pulping and paper-making processes could be calculated by combining the features of ChemSheet to process simulation performed with CheMac. The ultimate aim is to integrate CheMac with FlowMac and KraftMac.
The aims of the project were as follows:
- A separate PC calculation tool for pH and solubility in pulp suspensions.
- Data interchange between CheMac and pH calculation (spreadsheet or ASCII).
- Integrated pH-calculation in CheMac.
- Integrated solubility calculation in CheMac with the development of basic thermodynamic data files to describe the chemical composition of pulp suspensions in pulping and papermaking.
2. Achievements in the development work
The simulation tool developed combines the existing features of ChemSheet/ChemApp thermodynamic equilibrium calculation and flowsheet calculation by CheMac. To achieve that a completely new set of Blocks was developed and collected in a CheMac library. The Blocks in the CheMac library are then further combined and used in simulation models.
The ultimate aim is to later integrate CheMac with FlowMac and KraftMac. Blocks have been built to convert CheMac flows and data to FlowMac and vice versa, but the testing of these blocks are not done yet.
2.1 CheMac Library
The CheMac library developed, built on the Extend platform, is based on the thermodynamic chemistry database ChemAPP. The target has been to construct the pulp and paper making unit models with chemistry calculation.
CheMac uses a thermodynamic calculator for calculating equilibrium between vapour, water and fiber water phases. It also includes dissolution/precipitation of solid phases. Thermodynamic routines are in a separate dynamic link library (DLL) that is called from Extend models.
The following Blocks have been developed in the project;
a) Block used to initialize the thermodynamic system.
b) Blocks used for various processes such as:
· A Stage (acid stage)
· D Stage (ClO2 bleaching stage)
c) Blocks used for defining various feed flows such as:
· Pulp feed
· Water feed
· Gas feed
d) Blocks used to convert flows between FlowMac and CheMac:
· FlowMac to CheMac
· CheMac to FlowMac
2.2 CheMac Flowsheet
By combining and connecting several mixer and splitter blocks, the blocks described in section 2.1, different mill processes such as bleaching and washing can be simulated and predictions of washer and bleaching operations and performances are possible to simulate.
3. Connection with ABLE R&D co-operation
In the CheMac project, VTT PRO and ÅF are project partners in "Advanced Bleaching Plant" (ABLE) - research project. In the ABLE project, program modules for bleaching chemistry have been developed. However, since the development of ABLE modules is not finalised, the inclusion of bleaching chemistry modules into CheMac and hence FlowMac/KraftMac has not been fully implemented.
4. IPR, Intellectual Property Rights
The thermochemical calculation tool based on Chem Sheet, is customised for ÅF. The integrated calculation tool is best developed by using the library ChemApp (by GTT-Technologies, Aachen Germany) which is coupled to a modified interface, allowing it to be used together with FlowMac in the future. VTT has provided the calculation moedel as DLL library which utilizes the subset of ChemApp database (Eqfiber). This is developed to a ModChem DLL library, developed for ÅF as a customized application, for use of ÅF (and not to be sold as retail software product). Both parties have agreed and signed a research contract, which defines the mutual intellectual property rights (IPR) involved in this development work.