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AbstractThis paper presents the experimental plans and designs as well as examples of predictive modeling of a pilot-scale CO2 injection experiment at the Heletz site (Israel). The overall objective of the experiment is to find optimal ways to characterize CO2 -relevant in-situ medium properties, including field-scale residual and dissolution trapping, to explore ways of characterizing heterogeneity through joint analysis of different types of data, and to detect leakage. The experiment will involve two wells, an injection well and a monitoring well. Prior to the actual CO2 injection, hydraulic, thermal and tracer tests will be carried out for standard site characterization. The actual CO2 injection experiments will include (i) a single well injection-withdrawal experiment, with the main objective to estimate in-situ residual trapping and (ii) a two-well injection-withdrawal test with injection of CO2 in a dipole mode (injection of CO2 in one well with simultaneous withdrawal of water in the monitoring well), with the objective to understand the CO2 transport in heterogeneous geology as well as the associated dissolution and residual trapping. Tracers will be introduced in both experiments to further aid in detecting the development of the phase composition during CO2 transport. Geophysical monitoring will also be implemented. By means of modeling, different experimental sequences and injection/withdrawal patterns have been analyzed, as have parameter uncertainties. The objectives have been to (i) evaluate key aspects of the experimental design, (ii) to identify key parameters affecting the fate of the CO2 and (iii) to evaluate the relationships between measurable quantities and parameters of interest.

AbstractNORDICCS is a virtual CCS networking platform aiming for increased CCS deployment in the five Nordic countries. This paper reports from work investigating options for CO2 transport infrastructure in the Nordic region. Five specific CCS cases have been selected from which capture is analyzed in detail and from which CO2 transport cost has been calculated assuming CO2 being captured only at the site itself or, assuming the selected capture site develops into a CO2-hub with CO2 from several adjacent sources. In the latter case cost has been calculated defining for what volumes pipeline transport becomes less costly than corresponding ship transport. Additionally, cost for both pipeline and ship transport has been calculated as a function of distance and volume in order to apply these calculations to derive the least costly transport mode for the fifty-five largest sources in the region with a coastal location. Also, the effect on cost for systems that will require ramp-up (i.e. transported volumes increase over time) has been calculated. Finally, an analysis of the potential for build-up of clusters in the region was performed. The work clearly shows that ship transport is the least costly transport option, not only for the five selected cases individually but also for most of the emission sources located along the coastline. The work also shows that ship transport is the least costly transport option for most of the potential clusters in the region during the ramp-up phase. An obvious but still important conclusion is that constrained storage capability and injectivity may have a profound impact on design and cost of a CO2 transport system.

Abstract This paper is part two of a study on a CD 82 TMP chip refiner where relations between changes in the process conditions and changes in the properties of the produced pulp are investigated. Focus is on the ratio between tensile index and specific energy consumption when results from five tests are compared. Pulp properties were measured for composite pulp samples taken from the refiner blow line. Residence times and pulp consistencies were estimated by use of the extended entropy model. Clearly, an increase in specific energy does not necessarily implicate an increase in strength properties of the pulp produced. It is of high importance to have access to information about the refining zone conditions when searching for an optimal operation point in terms of the ratio between tensile index and specific energy. In these tests, this ratio had a maximum at about 55 % measured blow line consistency. Unfavourable operating conditions were identified at high pulp consistencies, especially after the FZ, where pulp consistencies well above 70 % were observed. The estimated residence time for each refining zone responded differently when applying changes in production rate, plate gaps and dilution water flow rates. In conclusion, the results associated with estimated pulp consistencies where easier to interpret compared with results for residence times, implying that additional tests are required for the latter variable. In addition to tensile index, pulp properties like freeness, Somerville shives and light scattering coefficient were included in the analysis.

Fe2O3-containing waste materials from the steel industry are proposed as oxygen carrier for chemical-looping combustion. Three such materials, red iron oxide, brown iron oxide and iron oxide scales, have been examined by oxidation and reduction experiments in a batch fluidized-bed reactor at temperatures between 800 and 950°C. NiO-based particles have been used as additive, in order to examine if it is possible to utilize the catalytic properties of metallic Ni to facilitate decomposition of hydrocarbons into more reactive combustion intermediates such as CO and H2. The experiments indicated modest reactivity between the waste materials and CH4, which was used as reducing gas. Adding small amounts of NiO-based particles to the sample increased the yield of CO2 in a standard experiment, typically by a factor of 1.5-3.5. The fraction of unconverted fuel typically was reduced by 70-90%. The conversion of CH4 to CO2 was 94% at best, corresponding to a combustion efficiency of 96%. This was achieved using a bed mass corresponding to 57 kg oxygen carrier per MW fuel, of which only 5 wt% was NiO-based synthetic particles. The different materials fared differently well during the experiments. Red iron oxide was fairly stable, while brown iron oxide was soft and subject to considerable erosion. Iron oxide scales experienced increased reactivity and porosity as function of the numbers of reduction cycles.

Carbon capture and storage (CCS) is expected to play a key role to achieve deep emission cuts in the energy intensive industry sector. The implementation of carbon capture comes with a considerable investment cost and a significant effect on the plants operating cost, which both depend on site conditions, mainly due to differences in flue gas flow and composition and depending on the availability of excess heat that can be utilized to power the capture unit. In this study we map the costs required to install and operate amine-based post-combustion CO2 capture at all manufacturing plants in Sweden with annual emissions of 500 kt CO2 or more, of both fossil and of biogenic origin, of which there are 28 plants (including a petrochemical site, refineries, iron and steel plants, cement plants and pulp and paper mills). The work considers differences in the investment required as well as differences in potential for using excess heat to cover the steam demand of the capture process. We present the resulting total CO2 capture costs in the form of a marginal abatement cost curve (MACC) for the emission sources investigated. Cost estimations for a transport and storage system are also indicated. The MACC shows that CO2 capture applied to 28 industrial units capture CO2 emissions corresponding to more than 50% of Swedish total CO2 emissions (from all sectors) at a cost ranging from around 40 €/t CO2 to 110 €/t CO2, depending on emission source. Partial capture from the most suited sites may reduce capture cost and, thus, may serve as a low-cost option for introducing CCS. The cost for transport and storage will add some 25 to 40 €/t CO2, depending on location and type of transportation infrastructure.

Abstract The CO2 absorption capacity in three hybrid solvents based on butyl-3-methylimidazolium acetate ([Bmim][OAc]) and three different cosolvents (Dimethyl ethers of polyethylene glycol (DEPG250), propylene carbonate, and water) was investigated and compared, and [Bmim][OAc]-DEPG250 shows the highest CO2 absorption capacity. The effects of the mass ratio of [Bmim][OAc]-DEPG250 and temperature on their CO2 absorption capacity, density, and viscosity were further investigated. In addition, the absorption capacities of N2 and CO2 in [Bmim][OAc]-DEPG250 with the simulated flue gas as a feed gas were studied and compared with that using the pure gas as a feed gas. Thermodynamic models were used to represent the experimental data, and then process simulation and evaluation were carried out. The results show that the addition of DEPG250 dramatically decreases the viscosity, while the absorption capacity of hybrid solvents is still comparable with pure [Bmim][OAc]. The type of gas stream, that is, pure gas or gas mixture, has a negligible effect on the N2 and CO2 absorption capacity. The simulation results show that [Bmim][OAc]-DEPG250 only utilizes less than 50% of the heating duty of aqueous amine solution because of the low-pressure desorption and preheating with waste heat in this hybrid solvent-based process. The CO2 capture cost of using this [Bmim][OAc]-DEPG250 reduces by 11% compared with that of using aqueous amine solution due to the significant decrease (by 52%) in utility cost.

AbstractChemical-looping combustion (CLC) is an unmixed combustion concept where fuel and combustion air are kept separate by means of an oxygen carrier, and the CO2 capture is inherently achieved. This work presents findings from a continuously operated 10kW pilot for solid fuels. Using petcoke as fuel, the following oxygen carriers are compared: (a) ilmenite, (b) ilmenite + lime, (c) manganese ore, and (d) manganese ore + lime. Compared to ilmenite, the use of manganese ore as oxygen carrier greatly enhanced the rate of gasification. By adding lime particles to the Mn ore, performance improved further. The addition of lime to ilmenite had a small beneficial effect on gas conversion and char gasification rate.

This study presents the effect of lignocellulosic compounds and monolignols on the yield, nanostructure and reactivity of soot generated at 1250 C in a drop tube furnace. The structure of soot was characterized by electron microscopy techniques, Raman spectroscopy and electron spin resonance spectroscopy. The CO2 reactivity of soot was investigated by thermogravimetric analysis. Soot from cellulose was more reactive than soot produced from extractives, lignin and monolignols. Soot reactivity was correlated with the separation distances between adjacent graphene layers, as measured using transmission electron microscopy. Particle size, free radical concentration, differences in a degree of curvature and multi-core structures influenced the soot reactivity less than the interlayer separation distances. Soot yield was correlated with the lignin content of the feedstock. The selection of the extraction solvent had a strong influence on the soot reactivity. The Soxhlet extraction of softwood and wheat straw lignin soot using methanol decreased the soot reactivity, whereas acetone extraction had only a modest effect.