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Although considered one of the major energy-intensive industries (EIIs), the pulp and paper industry has also the potential for energy production from an industrial waste, black liquor. This study proposes black liquor gasification (BLG) coupled with calcium looping (CaL) as a CO2 capture route for the pulp and paper industry. BLG with H2 production (BLG-CaL-H2), BLG with gas turbine combined cycle (BLG-CaL-GT) or with solid oxide fuel cell (BLG-CaL-SOFC) were considered. The dependence of carbon capture and storage (CCS) cost on the natural gas, limestone, electricity imported and H2 sale prices aside the expenditures related with BLG-CaL were evaluated. The CCS route, based on CaL retrofitted to the pulp and paper plant, was found to have a lower cost of CO2 avoided (39.0 €/tCO2) when compared with BLG-CaL (48.8–57.1 €/tCO2). Between the BLG-CaL scenarios, BLG-CaL-H2 presented the lowest cost of CO2 avoided (48.8 €/tCO2) but the highest energy penalty. Based on the thermodynamic performance, it was shown that CaL retrofit and BLG-CaL-SOFC presented the best overall performance, turning the electricity importer reference plant into electricity exporter. The economic sensitivity showed that the capital requirement of BLG-CaL has a strong effect on the cost of CO2 avoided for all alternatives. The H2 production is also strongly affected by the H2 sale price while BLG-CaL-SOFC and BLG-CaL-GT are strongly dependent on natural gas price.

This paper discusses the potential of gasoline, ethanol and methanol ternary blend as an alternative passenger car fuel in Sweden. Sweden has set various targets aimed to reduce its GHG emissions and to increase the share of renewables in the transportation sector. Nevertheless, the majority of the energy consumed in the road transportation sector still comes from fossil fuels. In order to replace the energy supply of fossil fuels by more renewable fuels, the potential of alternative renewable fuels needs to be explored. Therefore, the potential of a domestically produced ternary blend of Gasoline‐Ethanol‐ Methanol (GEM) fuel blend is analysed in this report. In order to test whether it has the potential to become a successful alternative fuel, an analysis is performed on the: methanol and ethanol production potential from domestic second‐generation feedstocks, the selection of the most suitable production pathways of the biofuels, the potential for a Swedish GEM fuel distribution infrastructure, the economic competitiveness of GEM fuel, and lastly on the environmental impact of the shift from cars running on neat gasoline to GEM fuel. In order to perform the analysis, two scenarios are developed for projecting the share of the GEM cars(cars running on GEM fuel blends) in the Swedish passenger car fleet, considering a time horizon from 2017 to 2030. In Scenario 1, a high share of passenger cars running on GEM fuel is obtained with 22 percent by 2030. In Scenario 2, a low share of cars running on GEM fuel is obtained with 17 percent by 2030. In both scenarios, the passenger cars running on GEM fuel take over the share of cars running on gasoline. The scenarios serve to project the energy demand for GEM fuels. By 2030, the projected energy demand for GEM fuels is 9.7 and 7.5 TWh for Scenario 1 and Scenario 2, respectively. From the biofuel potential studies, it can be concluded that the production potential of the alcohol fuels, derived from currently untapped domestic secondary resources, exceeds the projected energy demand of 9.7 and 7.5 TWh in 2030. According to this thesis, the production potential of 2nd generation ethanol and methanol are 36 and 61.1 TWh, respectively, by 2030. Moreover, the study shows that the majority of the existing fuel distribution network of E85 and gasoline, which is forecasted to have a significant overcapacity in the same time‐span as the scenarios, can be utilized in a GEM fuel distribution network. As a consequence, no major investments are required to develop a Swedish GEM fuel distribution network. Regarding the selection of the biofuel production pathways, this study indicates the most suitable way of producing methanol is by black‐liquor gasification. Regarding second‐generation ethanol, this thesis indicates that the fermentation forestry residues is the most beneficial production pathway. The biofuel production pathways are selected based on the energy yield ratios, the biofuel production cost and biomass feedstock cost. Moreover, this study demonstrates that under the current Swedish policies, GEM fuels blends are economic competitive with gasoline and E85. In order to test the economic competitiveness, a pay‐off curve was developed based on the pump price of gasoline and fuel economy of GEM fuel blends. This study shows the pump prices of GEM fuel blends pay‐off in comparison to gasoline. This analysis indicates that the pump prices of GEM fuel blends lays between 0.87 and 0.92 euro per liter. Regarding the environmental impact, this study indicates that the amount of GHG emissions avoided varies between 10.1 and 13.3 million metric tons CO2eq in Scenario 1. In Scenario 2, the amount of GHG emissions that can be avoided varies between 8.6 and 11.3 million metric tons CO2eq. Moreover, this study indicates that high methanol containing GEM fuel blend are more favourable in terms of biomass utilization, and high ethanol containing GEM fuel blends are more favourable in terms of economy and GHG savings.

The purpose of this thesis was to assess the feasibility of carbon capture in Finnish Kraft pulp mills. The feasibilities of thirteen different technology options were evaluated based on their technical maturity, capture potential and estimated break-even price for emission allowance including biogenic emissions. Also the role of pulp and paper in-dustry in climate change mitigation was discussed. The study was conducted by comparing oxy-fuel combustion cases modelled with Balas software and a fuel switch option calculated based on mass and energy balances with results from previous studies. The technical maturity was evaluated based on previous studies and existing commercial activity. The break-even prices from literature were recalculated under the same assumptions for investment costs, commodity costs and supporting policies. Two price estimates were calculated: one including supporting pol-icies and possibly available revenue and another excluding them. The capture potential was estimated using a reference mill scaled to the pulp production rate of 1200 ADt/d. Part of the technologies require large structural changes and were considered available only if the mill is rebuilt. Thus the capture potential in the reference mill was scaled up based on either the capture potential in mills to be rebuilt by 2030 or the capture poten-tial in all Finnish pulp mills. The relevant capture potential was calculated based on the production capacities and the estimated age distribution of the chemical recovery sec-tions in Finnish pulp mills. The results from this thesis were subjected to qualitative and numerical sensitivity analyses. Carbon capture in pulp mills seems feasible only if other revenues than CCS supporting policies are available. These revenues could include by-products like biofuels, higher energy efficiency or increased pulp production. The cases of lignin separation and black liquor gasification to transportation fuels were most cost efficient, but the capture poten-tials were limited to 1.45 Mt(CO2)/a and 0.82 Mt(CO2)/a, respectively. Small scale car-bon capture for utilization could be achieved with pre-calcination, as the break-even price was only around 4.5-7.3 /t(CO2). Large scale implementation of carbon capture in the Finnish pulp mills with monoethanolamine (MEA) absorption had a capture po-tential of up to 12 Mt(CO2)/a, but the break-even price was around 70-80 /t(CO2) ex-cluding transportation and storage costs. Moreover, barriers in transportation and stor-age and in the lack of incentives for bio-CCS remain. In addition to CCS, the pulp and paper industry could mitigate the climate change by increasing the amount of carbon based products, sustainable forestry practices and investments in forestation.

The purpose of this thesis was to assess the feasibility of carbon capture in Finnish Kraft pulp mills. The feasibilities of thirteen different technology options were evaluated based on their technical maturity, capture potential and estimated break-even price for emission allowance including biogenic emissions. Also the role of pulp and paper in-dustry in climate change mitigation was discussed. The study was conducted by comparing oxy-fuel combustion cases modelled with Balas software and a fuel switch option calculated based on mass and energy balances with results from previous studies. The technical maturity was evaluated based on previous studies and existing commercial activity. The break-even prices from literature were recalculated under the same assumptions for investment costs, commodity costs and supporting policies. Two price estimates were calculated: one including supporting pol-icies and possibly available revenue and another excluding them. The capture potential was estimated using a reference mill scaled to the pulp production rate of 1200 ADt/d. Part of the technologies require large structural changes and were considered available only if the mill is rebuilt. Thus the capture potential in the reference mill was scaled up based on either the capture potential in mills to be rebuilt by 2030 or the capture poten-tial in all Finnish pulp mills. The relevant capture potential was calculated based on the production capacities and the estimated age distribution of the chemical recovery sec-tions in Finnish pulp mills. The results from this thesis were subjected to qualitative and numerical sensitivity analyses. Carbon capture in pulp mills seems feasible only if other revenues than CCS supporting policies are available. These revenues could include by-products like biofuels, higher energy efficiency or increased pulp production. The cases of lignin separation and black liquor gasification to transportation fuels were most cost efficient, but the capture poten-tials were limited to 1.45 Mt(CO2)/a and 0.82 Mt(CO2)/a, respectively. Small scale car-bon capture for utilization could be achieved with pre-calcination, as the break-even price was only around 4.5-7.3 /t(CO2). Large scale implementation of carbon capture in the Finnish pulp mills with monoethanolamine (MEA) absorption had a capture po-tential of up to 12 Mt(CO2)/a, but the break-even price was around 70-80 /t(CO2) ex-cluding transportation and storage costs. Moreover, barriers in transportation and stor-age and in the lack of incentives for bio-CCS remain. In addition to CCS, the pulp and paper industry could mitigate the climate change by increasing the amount of carbon based products, sustainable forestry practices and investments in forestation.

Mitigation of climate change and energy security are major driving forces for increased biomass utilization. The pulp and paper industry consumes a large proportion of the biomass worldwide including bark, wood residues, and black liquor. Due to the fact that modern mills have established infrastructure for handling and processing biomass, it is possible to lay foundation for future gasification based bio-refineries to poly-produce electricity, chemicals or bio-fuels together with pulp and paper products. There is a potential to export electricity or bio-fuels by improving energy systems of existing chemical pulp mills by integrating gasification technology. The present study investigates bio-fuel alternatives from the dry black liquor gasification (BLG) system with direct causticization and direct methane production from the catalytic hydrothermal gasification (CHG) system. The studied systems are compared with bio-fuel alternatives from the Chemrec BLG system and the improvements in the energy systems of the pulp mill are analyzed. The results are used to identify the efficient route based on system performance indicators e.g. material and energy balances to compare BLG systems and the conventional recovery boiler system, potential biofuel production together with biomass to biofuel conversion efficiency, energy ratios, potential CO2 mitigation combining on-site CO2 reduction using CO2 capture and potential CO2 offsets from biofuel use, and potential motor fuel replacement. The results showed that the dry BLG system for synthetic natural gas (SNG) production offers better integration opportunities with the chemical pulp mill in terms of overall material and energy balances. The biofuel production and conversion efficiency are higher in the CHG system than other studied configurations but at a cost of larger biomass import. The dry BLG system for SNG production achieved high biomass to biofuel efficiency and considerable biofuel production. The energy ratio is significant in the dry BLG (SNG) system with less biomass demand and considerable net steam production in the BLG island. The elimination of the lime kiln in the dry BLG systems resulted in reduced consequences of incremental biomass import and associated CO2 emissions. Hydrogen production in the dry BLG system showed the highest combined CO2 mitigation potential i.e. on-site CO2 capture potential and CO2 offset from biofuel replacing fossil fuel. The results also showed that the motor fuel replacement potential with SNG as compressed natural gas (CNG) replacing gasoline in the transport sector is significantly high in countries with large pulp industry. QC 20120528

Black liquors are presently combusted in recovery boilers where the inorganic cooking chemicals are recovered and the energy in the organic material is converted to steam and electricity. A new technology, developed by Chemrec AB, is black liquor gasification (BLG). BLG has more to offer compared to the recovery boiler process, in terms of on-site generation of electric power, liquid fuel and process chemicals. A prerequisite for both optimization of existing processes and the commercialization of BLG is better understanding of the physical and chemical processes involved including interactions with the refractory lining. The chemistry in the BLG process is very complex and to minimize extensive and expensive time-consuming studies otherwise required accurate and reliable model descriptions are needed for a full understanding of most chemical and physical processes as well as for up-scaling of the new BLG processes. However, by using these calculated model results in practice, the errors in the state of the art thermochemical data have to be considered. An extensive literature review was therefore performed to update the data needed for unary, binary and higher order systems. The results from the review reviled that there is a significant range of uncertainty for several condensed phases and a few gas species. This resulted in experimental re-determinations of the binary phase diagrams sodium carbonate-sodium sulfide (Na2CO3-Na2S) and sodium sulfate-sodium sulfide (Na2SO4-Na2S) using High Temperature Microscopy (HTM), High Temperature X-ray Diffraction (HT-XRD) and Differential Thermal Analysis (DTA). For the Na2CO3-Na2S system, measurements were carried out in dry inert atmosphere at temperatures from 25 to 1200 °C. To examine the influence of pure CO2 atmosphere on the melting behavior, HTM experiments in the same temperature interval were made. The results include re-determination of liquidus curves, in the Na2CO3 rich area, melting points of the pure components as well as determination of the extent of the solid solution, Na2CO3(ss), area. The thermal stability of Na2SO3 was studied and the binary phase diagram Na2SO4-Na2S was re-determined. The results indicate that Na2SO3 can exist for a short time up to 750 °C, before it melts. It was also proved that a solid/solid transformation, not reported earlier, occurs at 675 ± 10 °C. At around 700 °C, Na2SO3 gradually breaks down within a few hours, to finally form the solid phases Na2SO4 and Na2S. From HTM measurements a metastable phase diagram including Na2SO3, as well as an equilibrium phase diagram have been constructed for the binary system Na2SO4-Na2S. Improved data on Na2S was experimentally obtained by using solid-state EMF measurements. The equilibrium constant for Na2S(s) was determined to be log Kf(Na2S(s)) (± 0.05) = 216.28 – 4750(T/K)–1 – 28.28878 ln (T/K). Gibbs energy of formation for Na2S(s) was obtained as ΔfG°(Na2S(s))/(kJ mol–1) (± 1.0) = 90.9 – 4.1407(T/K) + 0.5415849(T/K) ln (T/K). The standard enthalpy of formation of Na2S(s) was evaluated to be ΔfH°(Na2S(s), 298.15 K)/(kJ mol–1) (± 1.0) = – 369.0. The standard entropy was evaluated to be S°(Na2S(s), 298.15 K)/(J mol–1 K–1) (± 2.0) = 97.0. Analyses of used refractory material from the Chemrec gasifier were also performed in order to elucidate the stability of the refractory lining. Scanning electron microscopy (SEM) analysis revealed that the chemical attack was limited to 250-300 μm, of the surface directly exposed to the gasification atmosphere and the smelt. From XRD analysis it was found that the phases in this surface layer of the refractory were dominated by sodiumaluminosilicates, mainly Na1.55Al1.55Si0.45O4.