The degree project was done at Södra Cell Värö with the purpose to investigate how the use of energy for pulp drying in a pulp dryer could be made more effective to decrease the energy consumption or increase the capacity. The pulp dryer is one of the machines that consumes the most energy at SCV. The air that dryes the pulp is heated by low pressure steam, and since the amount low pressure steam was limited, the purpose with the project was to investigate how the low pressure steam best could be used. If the drying capacity could be improved it could enable for an increase in production or a decrease low pressure steam consumption. The task was divided into: 1. Analysis of steam and condensate flows connected to the pulp dryer. Can they be adjusted to improve the drying capacity? 2. Investigation of possible sectors of application for hot air flows from vacuum pumps. 3. Investigation of the condensate system. Can condensate and flash steam be used in a better way to provide more steam to the pulp dryer? For task 1, air and energy balances were made ove the pulp dryer, then temperature, flow and moisture content were measured for all air flows in and out. To investigate how the consumption low pressure steam in the pulp dryer depends on the air flows in to the pulp dryer, tests were made where the rotation speed for the fans and the temperature for the air were varied. The result of measuring the air balance over the pulp dryer was that the same amount air was going in and out, which means that all the air was going in to the dryer preheated. The energy balance over the thermal recycling system showed that 40 % of the energy in outgoing air was being reused. Increasing the rotation speed from 750 rpm to 1000 rpm was favourable when the production was high. Increasing the temperature of the air in to the pulp dryer showed that the consumption low pressure steam decreased. Recommended rotation speeds: December – february: 1000 rpm, all levels of production mars – november: 1000 rpm for high production (over 3 bar low pressure steam to pulp dryer) 750 rpm for low production (below 3 bar low pressure steam to pulp dryer) For task 2, temperature, flow and moisture content were measured for all air flows out from the vacuum pumps. The air flows out from the vacuum pumps had a temperature of 40-50 °C, which was too low to be used for preheating of air to pulp dryer. For task 3, a mapping of the condensate system including all steam and condensate flows connected to the pulp dryer was made. The mapping was made in AutoCAD. Since the experiment with increased temperature of the air in to the pulp dryer showed that an increase in temperature caused the consumption low pressure steam to decrease, calculations of how much more the consumption low pressure steam could be decreased by switching to steam of a higher pressure for preaheating the drying air. By using only steam of higher pressure for air preheating, the amount available low pressure steam to the pulp dryer could be increased with 6 tonnes/h. / Examensarbetet utfördes på Södra Cell Värö med syfte att undersöka hur energianvändningen för massatorkning på torkmaskinen (TM) kunde effektiviseras för att ge lägre energiförbrukning eller högre kapacitet. TM är en av de mest energiförbrukande avdelningarna på bruket. Massan torkas där med luft som värms av processånga vilken utgörs av lågtrycksånga, och eftersom tillgången av lågtrycksånga var begränsad var det önskvärt att undersöka hur den kunde användas på mest effektiva sätt. Om torkkapaciteten kan förbättras kan det möjliggöra en ökning av produktionen alternativt en minskning av förbrukning av lågtrycksånga. Uppgiften delades upp i: 1. Analys av ång- och luftflöden kopplat till TM. Kan de justeras för att ge bättre torkkapacitet? 2. Undersökning av möjliga användningsområden för varma luftflöden från vakuumpumparna. 3. Undersökning av kondensatsystemet. Kan kondensat och flashånga utnyttjas på ett bättre sätt för att tillhandahålla mer ånga till TM? Till uppgift 1 ställdes luft- och energibalanser upp över TM, och sedan gjordes mätningar på temperatur, flöde och fukthalt på in- och utgående luftflöden. För att undersöka hur förbrukningen lågtrycksånga i torkskåpet påverkas av tilluften gjordes försök där varvtal på tilluftfläktar och temperatur på tilluft varierades. Resultatet av luftbalansmätningarna var att inget undertryck rådde över torkskåpet, vilket innebär att all tilluft gick förvärmd in till torkningen. Energibalans över värmeåtervinningssystemet visade att ca 40 % av energin i utgående våtluft återvinns. Försök med varvtal och temperatur på tilluft visade att en ökning av varvtal från 750 rpm till 1000 rpm var gynnsamt vid hög produktion, samt att en temperaturökning på tilluft minskade förbrukningen lågtrycksånga i torkskåpet. Rekommenderade körinställningar: December-februari: 1000 rpm, alla produktionsnivåer Mars-november: 1000 rpm vid hög produktion (över 3 bars tryck på lågtrycksångan till skåpet) 750 rpm vid låg produktion (under 3 bars tryck på lågtrycksångan till skåpet) Till uppgift 2 gjordes mätningar på temperatur, flöde och fukthalt på utgående luftflöden från vakuumpumpar. Luftflödena från vakuumpumpar höll en temperatur på 40-50 °C, vilket var för lågt för att kunna användas till att förvärma torkluft till TM. Till uppgift 3 gjordes en kartering av kondensatsystemet inkluderande alla ång- och kondensatflöden kopplade till massatorkningen. Karteringen utfördes i AutoCAD. Eftersom försöket med temperaturökning på tilluft visade att lågtrycksångförbrukningen i skåpet minskade med ökad temperatur på tilluft, beräknades hur stor en ytterligare besparing lågtrycksånga skulle kunna bli om all tilluft förvärmdes av mellantrycksånga. Genom att använda mellantrycksånga för att förvärma all tilluft till torkskåpet skulle mängden tillgänglig lågtrycksånga till torkskåpet kunna ökas med 6 ton/h.

Munksunds pappersbruk är ett integrerat massa- och pappersbruk som består av två fiberlinjer, en barr- och en lövlinje där båda kokarna är kontinuerliga med efterföljande tvättsteg. En kartering av COD (eng. Chemical Oxygen Demand) och natrium utfördes för båda linjerna för att utvärdera tvätteffektiviteten. COD anger hur mycket syre som krävs för att bryta ned det kvarvarande organiska materialet och natrium används som en indikator på tvättförlusten av kokkemikalierna. Karteringen utfördes genom att analysera in- och utgående flöden vid varje tvättsteg, exklusive kokarna. En förenklad metod användes, där tre flöden analyserades och den fjärde beräknades genom flödes- och massbalanser. Modellen som användes för att beskriva tvätteffektiviteten för respektive utrustning var tvättutbytet Y, som erhölls genom en massbalans. Studien visade att halten COD och Natrium minskar mest från början för respektive linje och når ett gränsvärde runt 8,2 kg COD/adt och 6,6 kg Na/adt för barrlinjen, respektive 8,5 kg COD/adt och 4,8 kg Na/adt för lövlinjen, där ytterligare substans inte kan tvättas bort. Båda linjerna tvättar likvärt med avseende på COD, men lövlinjen tvättar bättre med avseende på natrium. I det sista tvättsteget hade båda fiberlinjerna eliminerat 98% av den inkommande COD-mängden med massan från kokarna. Vidare hade barrlinjen eliminerat 86% och lövlinjen 93% med avseende på natrium i det sista tvättsteget. Utvärderingen av de olika tvättutrustningarna visade att DD-filtret i lövlinjen var effektivast både med avseende på COD och natrium, följt av PO-pressen. På barrlinjen var filter 1 mest effektivt med avseende på COD och natrium. / A mapping of COD (Chemical oxygen demand) and sodium will be done to evaluate the different washing steps. COD describe the amount of oxygen needed to dissolve the organic matter left in the pulp and sodium is used as an indicator of the washing loss of the cooking chemicals. The in- and outgoing streams of the washing steps was analyzed to examine the efficiency. A simplified method was applied where three streams were analyzed and the fourth was calculated through flow-and mass balances. The model used to describe the wash efficiency in this study was the wash yield, which can be obtained by mass balances. The study showed that the content of COD and sodium decreased most in the beginning and reaches a limit value of 8,2 kg COD/adt and 6,6 kg Na/adt in the softwood pulp line and 8,5 kg COD/adt and 4,8 kg Na/adt in the soft wood pulp line, where no more content could be removed. Both pulp lines washed efficient with aspect of COD, but the hardwood pulp line washed more efficient in the aspect of natrium compared to the softwood pulp line. In the last washing step, both pulp lines had removed 98% of the ingoing COD from the digester. With aspect to natrium the softwood pulp line had removed 86% and the hardwood pulp line 93% in the last washing step. The evaluation of the different washing equipment showed that the DD-filter in the hardwood pulp line was the most efficient with aspect of both COD and Sodium, followed by the PO-press. In the softwood pulp line, filter 2 was the most efficient regarding both COD and Sodium. The flow- and mass balances turned out to be complicated at some of the washing steps, especially around the Q1-press in the hardwood pulp line and press 1-3 and filter 2 in the softwood pulp line. The reason for this could be that different functional chemicals are added before the Q1-press, which was not considered in this study, additional causes could be unidentified flows that affect the balances. The study was limited to only analyze three streams and calculate the fourth, an analyze of all the streams would give a more accurate result. However, the study provides a good overview of the wash efficiency in the pulp mill.

This thesis investigates the optimization of washing techniques before bleaching a pulp produced using ionic liquids. One pulp is from softwood and the other from wheat straw. Through experiments with varied temperatures and concentrations, the effectiveness of different washing conditions was evaluated, focusing on their impact on kappa number, viscosity, yield and reject amount for the softwood pulp. The wheat straw pulp was studied using the same optimal washing conditions that gave the best results for the softwood pulp. The results showed that washing at 75°C with 1.5% NaOH was the most effective. After washing, the softwood pulp had a kappa number of 20.0 and a viscosity of 162 mL/g. For the wheat straw pulp, the best result was a wash with 1.5% NaOH at 75°C, resulting in a kappa number of 16.2 and a viscosity of 446 mL/g. The washing process proved effective on a laboratory scale and the next step will be to conduct pilot-scale trials. The trials so far show that there is potential to scale up the washing of pulp produced by ionic liquid-based cooking. After washing, bleaching was performed using sodium chlorite. This method was suitable for laboratory-scale experiments, leading to a kappa number reduction from 20.0 down to 0.39 for the softwood pulp, with a viscosity loss from 162 mg/L down to 152 mL/g and a brightness of ISO 85%. For the wheat straw pulp, the kappa number decreased from 16.2 down to 0.62, the viscosity fall to 272 mL/g from 446 mg/L and the brightness reached ISO 76%. The study demonstrates that washing parameters can be optimized to achieve high brightness of the final bleached pulp without significantly altering its physical properties. The kappa number decreases while the viscosity remains relatively stable for the soft wood pulp, indicating that the process can consistently produce the same results. The wheat straw pulp lost viscosity from a high level. Loss of viscosity must be expected in some extent. The insights from this study reveal that pulp produced with ionic liquids can be washed and bleached effectively under control. The control of loss of viscosity is crucial for industrial applications. Future process development will require efficient chemical recovery. It is not possible to have wastes out of the process. It will be essential to close the process and it will ensure the sustainability of the process.

published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Dentistry / Master / Master of Dental Surgery

No description available.

North America is the world’s largest pulp and paper producing region as well as the largest consuming region. An understanding of market integration is critical for designing relevant policies since it is important to improve national welfare and ensure long-run competitive market equilibrium. In addition, it is crucial for the Canadian industry to maintain the competitiveness for its pulp and paper products in the world market, because any deterioration in the performance of the Canadian pulp and paper industry will have negative social and economic impact on the well-being of Canada and affect Canadian balance of payment. This thesis contains three essays that investigate the market integration of the combined markets of Canada and the US, and the competitive position of Canadian pulp and paper products in the US market. The first essay presents an econometric analysis of spatial integration of the US and Canada newsprint markets as reflected in newsprint prices. It applies the Johansen multivariate cointegration procedure to test the law of one price for five regional markets (British Columbia, Ontario, Quebec, US east, US west) of newsprint using monthly data for the 1988 to 2004 period. Preliminary data analysis shows that all price series are non-stationary I(1) processes. The hypothesis that the Law of One Price (LOP) holds for all five regional newsprint markets simultaneously was not supported by the Johansen multivariate test. The LOP was also tested for national markets, and it was found to hold between US west and US east newsprint prices. The results suggest that there is a single newsprint market in the US, whereas there are several distinct newsprint markets in Canada. The second essay examines the degree of market integration among US import markets for three pulp and paper products, and further analyses the dynamic interaction between US domestic and US import markets. Persistence profile results show that long-run equilibrium exists in the US import markets for three pulp and paper products of interest; moreover, given a system-wide shock, a new equilibrium could be reached in a relatively short period. Forecast error variance decomposition suggests that US markets are critical since shocks to domestic US prices for relevant pulp and paper products explain a substantial amount of movements in import prices. The third essay studies substitution between main categories of imported pulp and paper products and between imported and domestic pulp and paper products in the US market. A restricted translog subcost function approach was employed to derive the elasticity of substitution. The results suggest that Canadian pulp and paper products are still competitive and have maintained their competitiveness in the US market. However the consecutive demand decline for pulp and paper in the US has brought hard times to Canada. It seems that if Canadian pulp and paper industry wants to retain a dominant position in the world market place, it will have to create global reach and develop new markets.

Master of Agribusiness / Department of Agricultural Economics / Michael Boland / The Western Sugar Cooperative is a 135,000 acre sugar beet processing cooperative headquartered in Denver, Colorado with sugar beet processing factories located in Ft. Morgan CO, Torrington WY, Scottsbluff NE, Lovell WY, and Billings MT. The objective of the thesis is to analyze alternatives for maximizing the net revenue of co-products at Western Sugar. The ethanol policies of the U.S. government have had many unintended consequences including increasing the price of corn which is a key ingredient in animal feed production. Sugar beet co-products are produced in fixed proportions. That is, for every unit of sugar produced a corresponding unit of sugar beet pulp is created which is mostly water. Historically this has been dried into an animal feed pellets, however removing water from any high volume and high speed manufacturing process is energy intensive. Natural gas prices have increased dramatically and are projected to stay that way for a long time. As a result, the cost of manufacturing pellets is very high. The research shows that we are able to significantly increase our net income by increasing the percentage and price of pressed feed pulp rather than drying the pulp into pellets. This equals 20 million dollars of revenue in our pulp product line for the 2008-2009 sugar beet campaign. The thesis contains various analyses for changes in critical costs and prices. More importantly it details the subsequent management decisions implemented to maximize net income in the co-products business.

BACKGROUND: Thymoquinone (TQ) is one of the most active ingredients of Nigella sativa seed. TQ has a variety of pharmacologic properties including possess antinociceptive, antibacterial, anti-inflammatory, anti-oxidative activities and osteogenic effects on bone cells. Because of these properties, TQ might play an important role in odontogenic effects on human dental pulp cells and be used as a pulp capping material. PURPOSE: This study evaluates the effect of TQ on the attachment efficiency, proliferation, and odontogenic differentiation of Human Dental Pulp Cells (HDPC's). The effect of TQ on odontogenic differentiation was also determined by evaluating alkaline phosphatase (ALP) activity and Dentin Sialoprotein (DSP) expression. METHODS: Human dental pulp cells were cultured in triplicate using growth media with various TQ concentrations: 5 μM, 10μM, 15μM, 30μM, and 0μM as a control group at 7 and 21 days. Crystal violet staining was used to determine cell attachment efficiency and cell proliferation. The proliferation rates were normalized to cell numbers of each group at 16 hours. Cell differentiation was assessed by evaluating ALP activity and DSP expression. The data were normalized on per million cells basis. Univariate analyses including ANOVA and Student’s t-test were conducted. RESULTS: Higher cell attachment efficiency was shown in all TQ groups at 16 hours (P<. 0001) except for the 5 μM group. A significantly higher cell proliferation rate was shown with low TQ concentration 5 μM at 7 days (P<. 0001) and at 21days (P<. 0.05). However, the cell proliferation rates decreased significantly with higher TQ concentrations at both time intervals (P< 0.0001). Similarly, prolifration rates decreased at 21 days TQ =10 μM (P< 0.0001) and TQ =15 μM (P=0.0006). Significantly higher levels of alkaline phosphatase activity were observed in all TQ groups at 7 days (P <0.0001) and at 21 days (P <0.0001). Dentin sialoprotein expression was significantly down regulated in all TQ groups at 7 days compared to the control (P <0.05), however, at day 21 only TQ =15 μM exhibited significant down regulation of DSP compared to the control (P <0.0001). CONCLUSION: All tested TQ concentrations significantly enhanced cell attachment efficiency at 16 hours except TQ =5 μM. Cell proliferation rates were increased significantly by low TQ concentration 5 μM, and decreased significantly with higher TQ concentration 30 μM at 7 and 21 days. TQ exhibits odontogenic potential by inducing a significant increase in ALP activity at 7 and 21 days. TQ did not have any effect on DSP expression at 21 days except TQ =15 μM which significantly decreased DSP expression.