Reports within the forest industry research area

The overall aim of the project was to design and develop new environmentally friendly plasticizers from non-edible biobased products such as waste paper. During the project white writing paper and brown paper towels were liquefied by acid catalysed hydrolysis in the presence of ethylene glycol and glycerol. The liquefaction efficiency was good for brown paper, but the process did not work well in the case of white paper. The liquefied products were characterized by NMR, ESI-MS, SEC and SEM and used as monomers for synthesis of biobased plasticizers. A potential high volume application for these esters would be as plasticizers for poly (vinyl chloride) (PVC). The synthesized plasticizers were, thus, blended with PVC by solution casting and the blends were characterized for their mechanical propertiess anand miscibility by tensile testing. DSC and FTIR. The new plasticizers had similar or even better plasticizing efficency compared to traditional diisooctyl phthalate plasticizer. Novel bio-based plasticizers with high environmental and economic potential were, thus, successfuylly designed from non-edible liquefied biomass.

  10-065.pdf 

This study considers application of tertiary treatment of effluent water in two Swedish pulp mills in a holistic perspective. Calculations of improved waste water quality and costs for membrane filtration, chemical treatment *precipitation@ and sand filtration have been performed. The results differ considerably between the two plants as well as between treatment methods. Generally, nutrient discharges decrese more with chemical treatment than in other methods, while suspended solids are more effectively removed with filtration. Sand filtration is less expensive to install and operate than the other two methods.

The recipient to one of the mills is a large lake in central Sweden, while the other mill is located in a coastal area by the Bothnian Bay. Both recipients exhibit fairly good ecological status and the amounts of organic material and nutrients discharged by the mills are small compared to background loads. Simulations show no significant effects in the recipients of tertiary treatment of the pulp mill effluents. On the positive side, however, is the recipients of tertiary treatment load on the environment of some substances. Against this should be considered the environmental effects of building and operating the treatment plants.

Our analysis of the combined environmental effects of the different treatment methods show that the total nutrient emissions decrease in all cases. In all other categories the environmental impact increases due to i.a. increased consumption of energy and chemicals during building and operating the treatment plants and due to increased sludge production. There is no established way of comparing different categories of environmental impact, but we have applied different methods to assess and normalize different environmental impacts. Numerical results from the different categories can be normalized against total emissions per year and per peson in a certain region, or can be normalized against politically established emission targets in different categories. This gives an indication about how much of the ”available space” in a sustainable society that is consumed by the impacts. The monetary value of increased CO2 emissions can also be estimated using abatement costs in other instances or using the price in emissions trading markets. In similar ways the monetary value of decreased nutrient emissions can be assessed and compared against the increased climate impact from the treatment plats.

In summary the results indicate that the environmental benefit of tertiary treatment in the pulp mills is ambiguous in a holistic perspective. None of the methods to compare different impact categories in this study definitely answers the question whether the benefit exceeds the costs. One reason for this is that primary and secondary treatment of the effluent waters are already installed in the mills and the present environmental impact is limited. There is also lack of data concerning the effect on potentially toxic substances by the tertiary treatment, which is a significant gap in the environmental balance account.

09-158 Effekter av ytterligare reningssteg

The objectives of the project were to study some novel application of high frequency treatments and their effect on chemistry, structure and properties of Norway spruce wood. The project was focused on:

• Improved permeability of Norway spruce wood by high frequency treatments:

• Study the impact of treatments on structure and properties of wood to select the optimal treatment parameters with regards to specific processing afterwards;

• Comprehensively study the chemistry, anatomy, physical-mechanical properties of the treated spruce wood;

• Perform impregnation, laboratory and field standard decay tests to assess durability of treated and impregnated spruce wood.
  

08-065 Application of ultrasound....

Making paper with reasonable properties is a complex procedure that evolved over several centuries. At today mekmassaprocess exposed wood chips and fiber to mechanical load in several steps under the influence of water, water vapor and chemicals. The issue for this project is how resnonansfenomen can be used for energy efficiency of the process and improve fiber quality. The point is that the resonance can be used to concentrate the energy to frequency ranges that relate to the chip and fiber egenfrekrevenser and to monitor and control the cavitation. The initial analysis focused on both "lågfrekvensraffinering" focusing on the degradation of the chip and exposing the fiber, and "High frequency raffiniering", ie focus on fibrillation in the ultrasonic range.

06-279_ethanol_production_from_wood.pdf

The purpose of this study is to update the hypothetical reference mills developed in the 2005 FRAM project to reflect the technical changes that have occured in recent years. The main empahasis in this study is on the technical changes which have affected energy consumption and production.

There was no eucalyptus kraft pulp mill in the FRAM project, but such a mill has been included in this study.

  09-163fine-paper-final-jan-2011.pdf

The study analysis prerequisites for ethanol production from wood in Sweden with concern to market issues, production methods, raw material supply and current usage of requested raw material assortments.

From a Swedish perspective, cereals, sugar beet and several cellulosecontaining materials as straw, energy forest and wood are possible raw materials. At an early stage, Swedish research focused on wood, with branches and tops, as the primary resource for ethanol production. The R&D has so far only tested purer materials as wood chips and saw dust. Research progress within fermentation of pentose sugars, minimising water flows, optimising byproduct usage and integration concepts are also needed before large scale plants can be built.

The raw material competition is increasingly fierce with several sectors (pulp and paper, energy, saw mill, board producers and biofuel) competing for wood raw material. Our analysis indicates a raw material potential of 5 TWh (branches and tops) could be available for ethanol production under two conditions; an increased take-out of forest residues and usage of new raw material assortments from agriculture and forest. 5 TWh raw material corresponds to approximately 350 000 m3 ethanol. The EU biofuel directive recommends a substitution of fossil vehicle fuels of 5,75% and 10% 2010 respectively 2020. If these figures where to correspond to ethanol, 760 000 respectively 1 400 000 m3 ethanol will be needed. Thus, wood raw material cannot fully substitute fossil fuels without using assortments already used by other sectors.

Today, Swedish ethanol production (wheat) is expensive in comparison to production based on other raw materials as sugar cane or molasses. The reasons are lower cost for raw material and labour. Today, the custom duty on ethanol from countries outside is a condition for profitability of Swedish production. The Swedish government are currently working to annull the duty, which if succeded, will cause great difficulties for Swedish ethanol producers as the competition with imported ethanol from South America or Asia will be fierce. This situation may however change if the demand and price level continue to rise.

06-279_ethanol_production_from_wood.pdf

1   Background
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:

·        Mixer
·        Splitter
·        Washer
·        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.

05-076_chemac_finrep.pdf

The results from the 10 weeks storage experiment showed that storage of logs without bark is a good alternative to the traditional storage of logs with bark. The wood quality of both spruce and pine logs, with and without bark, remained quite good during the storage. After 10 weeks of storage, the largest cracks could be found in dry stored spruce logs without bark while the dry stored pine was most infested with blue stain. After the more normal storage time of three weeks the damages were limited. Sprinkling effectively protected the stored logs from wood damages. The run-off from logs without bark, for both spruce and pine, showed lower concentrations of organic material and phenols as well as higher pH compared to run-off from logs with bark. On the other hand the concentrations of phosphorus seemed to be increased in run-off from logs without bark. Since the wood quality was mainly preserved and the run-off for most analysed substances was cleaner when storing logs without bark the method has environmental advantages.

06-219_lakvattenkvalitet.pdf