Biomass procurement cost minimization for implementation of a retrofit biorefinery in a pulp and paper mil

As the forest industry emerges from the last economic recession, it finds itself evolving, to adjust to changes happening in their product markets (wood products, pulp and paper, etc.). In order to flourish in these new markets, many changes will come about in forestry firms, including expanding product portfolios by incorporating more biorefinery processes into current facilities. However, the added production of multiple value-added products along with current production will imply a more complete utilization of current feedstocks, and will most likely put a strain on the feedstock procurement supply chain.;Thus, as the transformation of mills into retrofit forest biorefineries occurs over a medium-to-long period of time, additional changes will have to occur throughout the mill (and company) supply-chains. These changes in procurement supply chains will have an impact on the bottom-line costs of the mill, and may ultimately determine whether or not a process is implemented. Therefore, it is in the best interest of the mills to explore biomass material procurement options beforehand, in order to better understand their effects on overall costs.;The objective of the project was to determine the conditions where different biomass procurement strategies for a biorefinery, result in reduced feedstock procurement costs, such that, they satisfy the facility's feedstock quantity and quality requirements, and are economically viable for a forestry firm in a competitive market.;A case study newsprint mill along with its forest material supply network was used to develop the necessary methodological framework and required modeling tools to prove the objectives.;The simulation, optimization, and their associated cost models aim to imitate realistic procurement activities to source forest material for all of their current (i.e. newsprint and cogeneration) and future (i.e. biorefinery) operations. Activity-based cost (ABC) accounting methods, were used within the simulation model, to calculate delivered product costs for each product extracted from each harvesting cutblock in the network, which was then used in the optimization model to fulfill the customers' feedstock demands on an annual basis.;The models can thus be used as a platform for evaluating various optimized procurement strategies for a company according to the process activities (which will determine the feedstock requirements) undertaken during the biorefinery's lifespan. This creates valuable feedstock quantity and cost information which will assist decision-makers in developing the correct biorefinery implementation strategy that considers existing feedstock resources within the area.;The project analyzed the feedstock procurement costs and feasibility of 11 biorefinery scenarios involving two biorefinery technologies (fast pyrolysis, and organic solvent pulping) retrofitted in a newsprint production mill, over a 20 year biorefinery project lifespan. During this time, the newsprint mill may (or may not) choose to partially (or completely) shut down newsprint production.;Along with the main pulp and paper production lines, and the implemented biorefinery processes, the mill also has a biomass boiler and cogeneration plant to produce steam and power consumed at the mill. Over the lifespan of the project, steam and power demands will change depending on the processes implemented, and so will the biomass demands of the boiler.;Along with process changes, other modifications are done to the biomass procurement supply chain and included within the optimization model as constraints. To reduce biomass procurement costs, forest harvesting systems are changed from cut-to-length to full-tree equipment over a 10 year period of time. This harvesting system change is expected to improve the integrated harvesting of multiple forest products (sawlogs, pulp logs, fuel logs and residues) as well as reduce harvesting costs due to the lower harvesting cost of using a full-tree system. Also, fibre exchange contracts are in place with local sawmills to exchange sawlogs harvested for chip materials used by the pulp and paper mill and biorefinery.;The tested scenarios focused on fulfilling feedstock demand according to available resources in the area, for the different processes being initiated or shutdown at the mill during the transition phases from P&P mill to biorefinery, while minimizing procurement costs over the lifespan of the project.;Biorefinery scenario analyses coupled with optimized biomass procurement costs for the simulated forest network determined which biorefinery implementation has the best technical and economic feasibility for the mill, and surrounding forest industry.;Results from the scenario analyses indicate that lower procurement costs are obtained when a pyrolysis process is implemented instead of an organic solvent due to the higher cost of providing hardwood chips from a forest with low amounts of hardwoods.;Certain trade-offs were found to be present in each scenario, that may affect their application in the newsprint mill used. The lowest cost procurement scenario for example involves the procurement of softwood chips for the pyrolysis process, as well as a complete exit from newsprint operations by year six. However, when analyzed with a biomass cost to revenue ratio, this scenario was found to have a value above 0.5 which makes it economically un-attractive. This is due in part to the trade-off of one commodity product (newsprint) for another (bio-oil) with lesser value (sold as a fuel oil substitute).;In other biorefinery scenarios that utilize higher quantities of products from the forest for both the current and future biorefinery processes (e.g. running newsprint while running pyrolysis biorefinery using hogfuel as a feedstock) tend to better utilize all the materials coming from harvesting operations (i.e. chips, residues, barks, hogfuels); nevertheless, they also tend to have higher total biomass costs per year due to the procurement of larger quantities of materials.;In the organic solvent pulping biorefinery, the biomass cost to revenue ratio was found to be acceptable only in scenarios where newsprint production was continued, due to the continued revenues from newsprint. Ideally in this situation the mill would increase the capacity of the organosolv process, however it was found that the biomass network cannot provide such large quantities of materials (above 1000 dry tonnes per day of woodchips for the biorefinery process). Thus, the decision on which procurement strategy to use will depend on whether the mill decides or not to maintain its newsprint production.;If newsprint production is continued, and a pyrolysis technology is selected, than the use of hogfuel as a feedstock for the pyrolysis process is better suited as it will reduce feedstock costs, since there is an abundance of unused hogfuel in the supply chain. On the other hand, if organic solvent production is used, newsprint production must be maintained and the scale of the organosolv process needs to be reduced to 750tpd for the biomass procurement network to be able to produce enough woodchips to supply both processes.;With the development and application of both simulation and optimization models to evaluate biorefinery scenarios, all the objectives of the PhD study were accomplished, and the hypotheses proven, while contributing to the body of knowledge.