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Ignition of suspensions of coal and biomass particles in air and oxy-fuel for Carbon Capture and Storage (CCS) and climate change mitigationTrabadela Robles, Ignacio January 2015 (has links)
Carbon Capture and Storage (CCS) is a legitimate technology option that should be part of a balanced portfolio of mitigation technologies available Post-Kyoto Protocol framework after Paris 2015 and beyond the 2020s or the cost achieving 2 degrees Celsius stabilisation scenario will significantly increase. Oxy-fuel combustion as a CCS technology option increases fuel flexibility. Additionally, oxy-biomass as a bio-energy with CCS (BECCS) technology can achieve negative carbon dioxide (CO2) emissions in sustainable biomass systems. Also, oxygen (O2) production in an air separation unit (ASU) gives potential for extra operational flexibility and energy storage. In this work, new designs of 20 litre spherical (R-20) and 30 litre non-spherical (R-30) ignition chambers have been built at the University of Edinburgh to carry-out dust ignition experiments with different ignition energies for evaluating pulverised fuel ignitability as a function of primary recycle (PR) O2 content for oxy-fuel PF milling safety. A set of coals and biomasses being used (at the time of submitting this work) in the utility pulverised fuel boilers in the UK have been employed. Coal and biomass dusts were ignited in air and oxy-fuel mixtures up to 30 % v/v O2 balance mixture CO2 where peak pressures (Pmax) from ignition were recorded. Pressure ratios (Pmax/Pinitial) were determined the key parameter for positive ignition identification with a value above 2.5 to be considered positive. Particle size effects in coal and biomass ignition were evaluated. Results on biomass were more variable than with coals, requiring a stronger ignition source (5,000 J) mainly due to larger particle sizes. Finer biomass particles behaved similarly to air ignition in 25 % v/v O2 in CO2. Larger particles of biomass did not ignite at all for most cases even reaching 30 % v/v O2 in CO2. A reference coal used, El Cerrejon, behaved as expected with 30 % v/v O2 balance CO2 matching air case; particles between 75-53 microns had lower ignitability than finer below 53 microns but were critical in devolatilisation. Most fuels did not ignite in 21 % v/v in CO2 below 200 g/m3 concentrations. The use of adequate ignition energy strength is needed for the PF mill safety case, with 5,000 J energy required for the biomasses tested. An indication of potential ignition chamber volume and geometry effect has also been observed when comparing results from R-20 and R-30 ignition chambers. Important implications include that oxy-biomass PR with 21 % v/v O2 content would give improved pulverised fuel (PF) milling safety when compared to air firing but reduced ignitability and a 25 % v/v O2 balance CO2 atmosphere would approach to oxy-biomass ignition behaviour in air in mills.
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Numerical modelling of geophysical monitoring techniques for CCSEid, Rami Samir January 2016 (has links)
I assess the potential of seismic and time-domain controlled-source electromagnetic (CSEM) methods to monitor carbon dioxide (CO2) migration through the application of a monitorability workflow. The monitorability workflow describes a numerical modelling approach to model variations in the synthetic time-lapse response due to CO2 migration. The workflow consists of fluid-flow modelling, rock-physics modelling and synthetic seismic or CSEM forward modelling. I model CO2 injected into a simple, homogeneous reservoir model before applying the workflow to a heterogeneous model of the Bunter Sandstone reservoir, a potential CO2 storage reservoir in the UK sector of the North Sea. The aim of this thesis is to model the ability of seismic and time-domain CSEM methods to detect CO2 plume growth, migration and evolution within a reservoir, as well as the ability to image a migrating front of CO2. The ability to image CO2 plume growth and migration within a reservoir has not been demonstrated in the field of CSEM monitoring. To address this, I conduct a feasibility study, simulating the time-lapse CSEM time-domain response of CO2 injected into a saline reservoir following the multi-transient electromagnetic (MTEM) method. The MTEM method measures the full bandwidth response. First, I model the response to a simple homogeneous 3D CO2 body, gradually increasing the width and depth of the CO2. This is an analogue to vertical and lateral CO2 migration in a reservoir. I then assess the ability of CSEM to detect CO2 plume growth and evolution within the heterogeneous Bunter Sandstone reservoir model. I demonstrate the potential to detect stored and migrating CO2 and present the synthetic results as time-lapse common-offset time sections. The CO2 plume is imaged clearly and in the right coordinates. The ability to image seismically a migrating front of CO2 remains challenging due to uncertainties regarding the pore-scale saturation distribution of fluids within the reservoir and, in turn, the most appropriate rock-physics model to simulate this: uniform or patchy saturation. I account for this by modelling both saturation models, to calculate the possible range of expected seismic velocities prior to generating and interpreting the seismic response. I demonstrate the ability of seismic methods to image CO2 plume growth and evolution in the Bunter Sandstone saline reservoir model and highlight clear differences between the two rock-physics models. I then modify the Bunter Sandstone reservoir to depict a depleted gas field by including 20% residual gas saturation. I assess the importance and implication of patchy saturation and present results which suggest that seismic techniques may be able to detect CO2 injected into depleted hydrocarbon fields.
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Carbon dioxide enhanced oil recovery, offshore North Sea : carbon accounting, residual oil zones and CO2 storage securityStewart, Robert Jamie January 2016 (has links)
Carbon dioxide enhanced oil recovery (CO2EOR) is a proven and available technology used to produce incremental oil from depleted fields. Although this technology has been used successfully onshore in North America and Europe, projects have maximised oil recovery and not CO2 storage. While the majority of onshore CO2EOR projects to date have used CO2 from natural sources, CO2EOR is now more and more being considered as a storage option for captured anthropogenic CO2. In the North Sea the lack of low cost CO2, in large volumes, has meant that no EOR projects have utilised CO2 as an injection fluid. However CO2EOR has the highest potential of all EOR techniques to maximise recovery from depleted UK oil fields. With the prospect of Carbon Capture and Storage (CCS) capturing large tonnages of CO2 from point source emission sites, the feasibility of CO2EOR deployment in the North Sea is high. This thesis primarily aims to address a number of discrete issues which assess the effectiveness of CO2EOR to both produce oil and store CO2. Given the fundamental shift in approach proposed in North Sea CO2EOR projects, the carbon balance of such projects is examined. Using a life cycle accounting approach on a theoretical North Sea field, we examine whether offshore CO2EOR can store more CO2 than onshore projects traditionally have, and whether CO2 storage can offset additional emissions produced through offshore operations and incremental oil production. Using two design scenarios which optimise oil production and CO2 storage, we find that that net GHG emissions were negative in both ‘oil optimised’ and ‘CO2 storage optimised’. However when emissions from transporting, refining and combusting the produced crude oil are incorporated into the life cycle calculations the ‘oil optimised scenario’ became a net emitter of GHG and highlights the importance of continuing CO2 import and injection after oil production has been maximised at a field. This is something that has not traditionally occurred. After assessing rates of flaring and venting of produced associated gas at UK oil fields it is found that the flaring or venting of reproduced CH4 and CO2 has a large control on emissions. Much like currently operating UK oil fields the rates of flaring and venting has a control on the carbon intensity of oil produced. Here values for the carbon intensity of oil produced through CO2EOR are presented. Carbon intensity values are found to be similar to levels of current UK oil production and significantly lower than other unconventional sources. As well as assessing the climate benefits of CO2EOR, a new assessment of CO2EOR potential in Residual Oil Zones (ROZ) is also made. ROZ resource, which is thought to add significant potential to both the oil reserves and CO2 storage potential in some US basins, is here identified in the North Sea for the first time. Based on the foundation of North Sea hydrodynamics study, this thesis identifies the Pierce field as a candidate ROZ field where hydrodynamic tilting of the oil water contact has naturally occurred leaving a zone of residual oil. To test the feasibility of CO2EOR in such a zone a methodology is presented and applied. Notably the study highlights that in this case study recoverable reserves from the ROZ may approach 20% of total field recoverable reserves and have the capability to store up to 11Mt of CO2. While highlighting the CO2EOR potential in the ROZ the thesis discusses the importance in expanding the analysis to quantify its importance on a basin scale. Discussion is also made on whether new resource identification is necessary in a mature basin like the North Sea. With CO2EOR being considered as a feasible option for storing captured anthropogenic CO2, it is important to assess the security of storage in CO2EOR. Using real geochemical and production data from a pilot CO2EOR development in Western Canada two approaches are used to assess the partitioning of CO2 between reservoir fluids through time. Using a number of correlations it is found that CO2 dissolution in oil is up to 7 times greater than in reservoir brine when saturations between the two fluids are equal. It is found that after two years of CO2 injection solubility trapping accounts for 26% of injected CO2. The finding that significantly more dissolution occurs in oil rather than brine indicates that CO2 storage in EOR is safer than in brine storage. However a number of factors such as the increase in oil/CO2 mobility due to CO2 injection is also discussed. The overall conclusion from the work is that CO2EOR in the North Sea has the potential to be an effective way of producing oil and storing CO2 in the North Sea. A number of design, operational and accounting factors are however essential to operate an exemplar CO2EOR project where low carbon intensity oil can be produced from a mature basin while storing large tonnages of captured anthropogenic CO2.
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Carbon dioxide sequestration methodothologies - A reviewMwenketishi, G., Benkreira, Hadj, Rahmanian, Nejat 30 November 2023 (has links)
Yes / The process of capturing and storing carbon dioxide (CCS) was previously considered a crucial and time-sensitive approach for diminishing CO2 emissions originating from coal, oil, and gas sectors. Its implementation was seen necessary to address the detrimental effects of CO2 on the atmosphere and the ecosystem. This recognition was achieved by previous substantial study efforts. The carbon capture and storage (CCS) cycle concludes with the final stage of CO2 storage. This stage involves primarily the adsorption of CO2 in the ocean and the injection of CO2 into subsurface reservoir formations. Additionally, the process of CO2 reactivity with minerals in the reservoir formations leads to the formation of limestone through injectivities. Carbon capture and storage (CCS) is the final phase in the CCS cycle, mostly achieved by the use of marine and underground geological sequestration methods, along with mineral carbonation techniques. The introduction of supercritical CO2 into geological formations has the potential to alter the prevailing physical and chemical characteristics of the subsurface environment. This process can lead to modifications in the pore fluid pressure, temperature conditions, chemical reactivity, and stress distribution within the reservoir rock. The objective of this study is to enhance our existing understanding of CO2 injection and storage systems, with a specific focus on CO2 storage techniques and the associated issues faced during their implementation. Additionally, this research examines strategies for mitigating important uncertainties in carbon capture and storage (CCS) practises. Carbon capture and storage (CCS) facilities can be considered as integrated systems. However, in scientific research, these storage systems are often divided based on the physical and spatial scales relevant to the investigations. Utilising the chosen system as a boundary condition is a highly effective method for segregating the physics in a diverse range of physical applications. Regrettably, the used separation technique fails to effectively depict the behaviour of the broader significant system in the context of water and gas movement within porous media. The limited efficacy of the technique in capturing the behaviour of the broader relevant system can be attributed to the intricate nature of geological subsurface systems. As a result, various carbon capture and storage (CCS) technologies have emerged, each with distinct applications, associated prices, and social and environmental implications. The results of this study have the potential to enhance comprehension regarding the selection of an appropriate carbon capture and storage (CCS) application method. Moreover, these findings can contribute to the optimisation of greenhouse gas emissions and their associated environmental consequences. By promoting process sustainability, this research can address critical challenges related to global climate change, which are currently of utmost importance to humanity. Despite the significant advancements in this technology over the past decade, various concerns and ambiguities have been highlighted. Considerable emphasis was placed on the fundamental discoveries made in practical programmes related to the storage of CO2 thus far. The study has provided evidence that despite the extensive research and implementation of several CCS technologies thus far, the process of selecting an appropriate and widely accepted CCS technology remains challenging due to considerations related to its technological feasibility, economic viability, and societal and environmental acceptance.
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A comprehensive review on carbon dioxide sequestration methodsMwenketishi, G., Benkreira, Hadj, Rahmanian, Nejat 09 December 2023 (has links)
Yes / Capturing and storing CO2 (CCS) was once regarded as a significant, urgent, and necessary option for reducing the emissions of CO2 from coal and oil and gas industries and mitigating the serious impacts of CO2 on the atmosphere and the environment. This recognition came about as a result of extensive research conducted in the past. The CCS cycle comes to a close with the last phase of CO2 storage, which is accomplished primarily by the adsorption of CO2 in the ocean and injection of CO2 subsurface reservoir formation, in addition to the formation of limestone via the process of CO2 reactivity with reservoir formation minerals through injectivities. CCS is the last stage in the carbon capture and storage (CCS) cycle and is accomplished chiefly via oceanic and subterranean geological sequestration, as well as mineral carbonation. The injection of supercritical CO2 into geological formations disrupts the sub-surface’s existing physical and chemical conditions; changes can occur in the pore fluid pressure, temperature state, chemical reactivity, and stress distribution of the reservoir rock. This paper aims at advancing our current knowledge in CO2 injection and storage systems, particularly CO2 storage methods and the challenges encountered during the implementation of each method and analyses on how key uncertainties in CCS can be reduced. CCS sites are essentially unified systems; yet, given the scientific context, these storage systems are typically split during scientific investigations based on the physics and spatial scales involved. Separating the physics by using the chosen system as a boundary condition is a strategy that works effectively for a wide variety of physical applications. Unfortunately, the separation technique does not accurately capture the behaviour of the larger important system in the case of water and gas flow in porous media. This is due to the complexity of geological subsurface systems, which prevents the approach from being able to effectively capture the behaviour of the larger relevant system. This consequently gives rise to different CCS technology with different applications, costs and social and environmental impacts. The findings of this study can help improve the ability to select a suitable CCS application method and can further improve the efficiency of greenhouse gas emissions and their environmental impact, promoting the process sustainability and helping to tackle some of the most important issues that human being is currently accounting global climate change. Though this technology has already had large-scale development for the last decade, some issues and uncertainties are identified. Special attention was focused on the basic findings achieved in CO2 storage operational projects to date. The study has demonstrated that though a number of CCS technologies have been researched and implemented to date, choosing a suitable and acceptable CCS technology is still daunting in terms of its technological application, cost effectiveness and socio-environmental acceptance.
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A novel approach to solvent screening for post-combustion carbon dioxide capture with chemical absorptionRetief, Frederik Jacobus Gideon 14 March 2012 (has links)
Thesis (MScEng)--Stellenbosch University. / ENGLISH ABSTRACT: Carbon dioxide (CO2) is classified as the main greenhouse gas (GHG) contributing to global warming.
Estimates by the Intergovernmental Panel on Climate Change (IPCC) suggest that CO2 emissions must be
reduced by between 50 to 85% by 2050 to avoid irreversible impacts. Carbon capture and storage (CCS)
strategies can be applied to de-carbonize the emissions from fossil-fueled power plants. Compared to
other CCS techniques, post-combustion capture (PCC) is most likely to be implemented effectively as a
retrofit option to existing power plants. At present however CCS is not yet commercially viable. The
main challenge with CCS is to reduce the inherent energy penalty of the CO2 separation stage on the
host plant.
Seventy-five to eighty percent of the total cost of CCS is associated with the separation stage. There are
several technologies available for separating CO2 from power plant flue gas streams. Reactive absorption
with aqueous amine solutions has the ability to treat low concentration, low pressure and large flux flue
gas streams in industrial-scale applications. It is most likely to be the first technology employed
commercially in the implementation of CCS. The energy required for solvent regeneration however, is
high for the standard solvent used in reactive absorption processes, i.e. MEA. This leads to a reduction in
thermal efficiency of the host plant of up to 15%. Alternative solvent formulations are being evaluated in
an attempt to reduce the energy intensity of the regeneration process.
The main objective of this study was to establish a novel, simplified thermodynamic method for solvent
screening. Partial solubility parameters (PSPs) were identified as the potential basis for such a method.
The major limitation of this approach is that the model doesn’t account for effects from chemical
reaction(s) between materials, e.g. CO2 reacting with aqueous alkanolamine solutions; considering only
the effects from dissolution. The EquiSolv software system was developed based on PSP theory. The
Hansen 3-set PSP approach was used to describe the equilibrium behaviour of CO2 absorbing in task
specific solvents. The Hansen theory was expanded to a 4-set approach to account for contributions
from electrostatic interactions between materials. The EquiSolv program was used successfully to screen
large sets of solvent data (up to 400 million formulations) in the search for suitable alternative solvent
formulations for CO2 absorption.
The secondary objective of this study was to evaluate the ability of the proposed PSP model to
accurately predict suitable alternative solvents for CO2 absorption through preliminary experimental
work. A series of CO2 absorption experiments were conducted to evaluate the absorption performance
of predicted alternative solvent formulations. The predicted alternative solvent formulations exhibited a
significant improvement in absorption performance (up to a 97% increase in the measured absorption
capacity) compared to conventional solvent formulations. Statistical analysis of the experimental results
has shown that there is a statistically significant concordant relationship between the predicted and
measured rankings for the absorption performance of the predicted solvent formulations. Based on this
it was concluded that PSP theory can be used to accurately predict the equilibrium behaviour of CO2
absorbing in task specific solvents.
Recently ionic liquids (ILs) have been identified as potential alternatives to alkanolamine solutions
conventionally used for CO2 absorption. Absorption experiments were conducted as a preliminary
assessment of the absorption performance of ILs. Results have shown ILs to have significantly improved
performance compared to conventional alkanolamine solvents; up to a 96% increase in the measured
absorption capacity compared to conventional solvents. Future work should focus on developing task
specific ionic liquids (TSILs) in an attempt to reduce the energy intensity of solvent regeneration in CO2
absorption processes. / AFRIKAANSE OPSOMMING: Koolsuurgas (CO2) word geklassifiseer as die vernaamste kweekhuis gas (GHG) wat bydra to globale
verwarming. Beramings deur die Interregeringspaneel oor Klimaatsverandering (IPKV) toon aan dat CO2
emissies teen 2050 verminder moet word met tussen 50 en 85% om onomkeerbare invloede te vermy.
Verskeie koolstof opvangs en bergings (KOB) strategieë kan toegepas word ten einde die koolstof
dioksied konsentrasie in die emissies van kragstasies wat fossielbrandstowwe gebruik, te verminder. Naverbranding
opvangs (NVO) is die mees aangewese KOB tegniek wat effektief toegepas kan word op
bestaande kragstasies. Tans is KOB egter nog nie kommersieël lewensvatbaarvatbaar nie. Die hoof
uitdaging wat KOB in die gesig staar is om die energie boete inherent aan die CO2 skeidingstap te
verminder.
Tussen vyf-en-sewentig en tagtig persent van die totale koste van KOB is gekoppel aan die skeidingstap.
Daar is verskeie metodes beskikbaar vir die skeiding van CO2 uit die uitlaatgasse van kragstasies.
Reaktiewe absorpsie met waterige oplossings van amiene kan gebruik word om lae konsentrasie, lae
druk en hoë vloei uitlaatgasstrome in industriële toepassings te behandel. Dit is hoogs waarskynlik die
eerste tegnologie wat kommersieël aangewend sal word in die toepassing van KOB. Die oplosmiddel wat
normalweg vir reaktiewe absorpsie gebruik word (d.w.s. MEA) benodig egter ‘n groot hoeveelheid
energie vir regenerasie. Dit lei tot ‘n afname in die termiese doeltreffendheid van die voeder aanleg van
tot 15%. Alternatiewe oplosmiddelstelsels word tans ondersoek in ‘n poging om the energie intensiteit
van die regenerasieproses te verminder.
Die hoof doelwit van hierdie studie was om ‘n nuwe, ongekompliseerde termodinamiese metode te
vestig vir die keuring van alternatiewe oplosmiddels. Parsiële oplosbaarheidsparameters (POPs) is
geïdentifiseer as ‘n moontlike grondslag vir so ‘n metode. Die model beskryf egter slegs die ontbindings
gedrag van materiale. Die effekte van chemise reaksie(s) tussen materiale, bv. die tussen CO2 en
waterige oplossings van alkanolamiene, word nie in ag geneem nie. Die POP teorie het gedien as
grondslag vir die ontwerp van die EquiSolv sagteware stelsel. Die Hansen stel van drie POPs is gebruik
om die ewewigsgedrag te beskryf van CO2 wat absorbeer in doelgerig-ontwerpte oplosmiddels. Die
Hansen teorie is verder uitgebrei na ‘n stel van vier POPs om die bydrae van elektrostatiese wisselwerking tussen materiale in ag te neem. Die EquiSolv program is verskeie kere met groot sukses
gebruik vir die sifting van groot stelle data (soveel as 400 miljoen formulasies) in die soektog na
alternatiewe oplosmiddels vir CO2 absorpsie.
Die sekondêre doelwit van die studie was om die vermoë van die voorgestelde POP model om geskikte
alternatiewe oplosmiddels vir CO2 absorpsie akkuraat te voorspel, te ondersoek deur voorlopige
eksperimentele werk. ‘n Reeks CO2 absorpsie eksperimente is gedoen ten einde die absorpsie
werkverrigting van die voorspelde alternatiewe oplosmidels te ondersoek. ‘n Verbetering in absorpsie
werkverrigting van tot 97% is gevind vir die voorspelde oplosmiddels vergeleke met die van
oplosmiddels wat tipies in die industrie gebruik word. Statistiese ontleding van die eksperimentele
resultate het getoon dat daar ‘n beduidende ooreenstemming tussen die voorspelde en gemete
rangskikking van die voorspelde oplosmiddels se werkverrigting bestaan. Dus kan POP teorie gebruik
word om die absorpsie van CO2 in doelgerig-ontwerpte oplosmiddels akkuraat te beskryf.
Ioniese vloeistowwe (IVs) is onlangs geïdentifiseer as moontlike alternatiewe oplosmidels vir die
alkanolamien oplossings wat normaalweg gebruik word vir CO2 absorpsie. Absorpsie eksperimente is
gedoen ten einde ‘n voorlopige raming van die absorpsie werkverrigting van IVs te bekom. Daar is
bevind dat IVs ‘n beduidende verbetering in werkverrigting toon in vergelyking met die alkanolamien
oplosmiddels wat normaalweg gebruik word. ‘n Verbetering in absorpsie werkverrigting van tot 96% is
gevind vir die voorspelde IV-bevattende oplosmiddels vergeleke met die van oplosmiddels wat tipies in
die industrie gebruik word. Die fokus van toekomstige navorsing moet val op die ontwikkeling van
doelgemaakte ioniese vloeistowwe (DGIVs) in ‘n poging om die energie intensiteit van oplosmiddel
regenerasie in CO2 absorpsie prosesse te verminder.
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Enhanced CO2 Storage in Confined Geologic FormationsOkwen, Roland Tenjoh 30 September 2009 (has links)
Many geoscientists endorse Carbon Capture and Storage (CCS) as a potential strategy
for mitigating emissions of greenhouse gases. Deep saline aquifers have been reported to
have larger CO
2 storage capacity than other formation types because of their availability
worldwide and less competitive usage. This work proposes an analytical model for screening
potential CO
2 storage sites and investigates injection strategies that can be employed to
enhance CO
2 storage.
The analytical model provides of estimates CO 2
storage efficiency, formation pressure
profiles, and CO 2
–brine interface location. The results from the analytical model were
compared to those from a sophisticated and reliable numerical model (TOUGH 2
). The
models showed excellent agreement when input conditions applied in both were similar.
Results from sensitivity studies indicate that the agreement between the analytical model
and TOUGH2 strongly depends on irreducible brine saturation, gravity and on the relationship
between relative permeability and brine saturation.
A series of numerical experiments have been conducted to study the pros and cons of
different injection strategies for CO 2 storage in confined saline aquifers. Vertical, horizontal,
and joint vertical and horizontal injection wells were considered. Simulations results
show that horizontal wells could be utilized to improve CO 2 storage capacity and efficiency
in confined aquifers under pressure-limited conditions with relative permeability
ratios greater than or equal to 0:01. In addition, joint wells are more efficient than single
vertical wells and less efficient than single horizontal wells for CO 2 storage in anisotropic
aquifers.
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Three essays on energy efficiency and environmental policies in CanadaGamtessa, Samuel Faye Unknown Date
No description available.
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Technoeconomical evaluation of small-scale CO2 liquefaction using Aspen Plus / Teknoekonomisk utvärdering av småskalig förvätskning av CO2 med Aspen PlusSvanberg Frisinger, Maja-Stina January 2021 (has links)
Syftet med den här studien är att göra en teknoekonomisk utvärdering av processer för förvätskning av CO2 med hjälp av Aspen Plus. Ett flertal förvätskningsprocesser från tidigare studier jämfördes och från dessa valdes två förvätskningsprocesser ut för fortsatta studier och simuleringar. Dessa två förvätskningsprocesser var ett internt kylt förvätskningssystem och ett externt kylt förvätskningssystem av Øi et al., Energy Procedia 86 (2016) 500-510, som kallats system A, samt av Seo et al., International Journal of Greenhouse Gas Control 35 (2015) 1-12 kallat system B. Dessa två olika processer simulerades för teknisk analys med hjälp av Aspen Plus. Aspen Economical Analyzer (AEA) användes för att göra den ekonomiska analysen. I dessa simuleringar användes ett massflöde på 45 ton/h inkluderat vatteninnehåll, i jämförelse med tidigare studier med högre massflöden runt 100 ton/h. Elektricitet-och kylbehovet undersöktes i ett flertal olika fall med varierande kyltemperatur mellan kompressorerna. Två fall med integrering av fjärrvärme samt två fall med en värmepump undersöktes också med varierande återgående temperatur på fjärrvärmevattnet. Detta gjordes för att undersöka hur mycket värme som kan tillvaratas från förvätskningsprocessen. Vidare bestämdes även investeringskostnader samt driftskostnader med hjälp av AEA. Från detta bestämdes även den årliga kostnaden av kapitalet, CAPEX, och kostnaden att förvätska CO2 räknades ut i form av €/ton. Resultaten visade att integrering av fjärrvärme samt värmepumpar är användbart för att tillvarata på så mycket värme som möjligt från förvätskningssystemen. I de fall med en värmepump samt en återgående temperatur på 47°C i fjärrvärmenätet hade ett COP på 3.07 samt 3.15 för system A samt system B vardera. Kostanden att förvätska CO2 var 17.42 €/ton för system A samt 17.75 €/ton för system B utan använding av en värmepump samt en återgående temperatur på 47°C i fjärrvärmenätet. Vid integrering av en värmepump gick kostnaden av förvätskning upp till 20.85 €/ton för system A samt 21.69 €/ton för system B. Kostnaden av förvätskning dominerades av driftskostnader med kostnaden av kapitalet har en mindre påverkan. Utnyttjandegraden har även en stor påverkan på kostanden av förvätskning, då lägre kapaciteter visade sig leda till markant högre förvätskningskostnader. När intäkterna från fjärrvärmeproduktionen adderades till kostnadskalkylen, minskade kostnaden av förvätskning, speciellt för de system med en värmepump, där priset minskade till 10.26 €/ton för system A eller 10.98 €/ton för system B. I linje med tidigare studier pekar även dessa resultat på att det ekonomiska optimumet sammanfaller med energioptimum. Resultaten visade även att system A, det internt kylda systemet, hade den lägsta förvätskningskostanden och minsta elektricitetsförbrukningen med och utan värmepump, och därför är system A optimalt för småskalig CO2 förvätskning. / The aim of this study is to do a technoeconomical analysis on CO2 liquefaction systems using Aspen Plus. Several liquefaction systems from previous studies were compared, and from these, two liquefaction systems were chosen for further studies and simulations. These liquefaction systems were namely an internal liquefaction system and an external liquefaction system by Øi et al., Energy Procedia 86 (2016) 500-510, called system A and Seo et al., International Journal of Greenhouse Gas Control 35 (2015) 1-12, called system B. These systems were simulated for technical analysis using Aspen Plus, and Aspen Economical Analyzer (AEA) was used for economical studies. A small-scale liquefaction system was studied with a mass flow rate of 45 tonne/h including the water content, as compared to other studies with higher mass flow rates of around 100 tonne/h. The electricity demand and cooling demand were studied in several cases of interstage cooling between compressors. Furthermore, two cases of district heating as well as two cases of heat pumps were studied with varying return temperatures of the district heating water. This was done to study how much heat could be recovered from the liquefaction process. Furthermore, the capital expenses as well as the operating expenses were also determined using AEA. From this, the annual CAPEX and the cost of CO2 was calculated in terms of €/tonne CO2. The results showed that district heating and heat pumps can be useful to recover heat from the liquefaction processes. The simulations that included a heat pump and assumed a return temperature of 47°C had a COP of 3.07 and 3.15 for system A and B respectively. The determined cost of production was 17.42 €/tonne for system A and 17.75 €/tonne for system B when not using a heat pump and a return temperature of 47°C in the district heating grid. However, when adding a heat pump the total production cost (TPC) increased to 20.85 €/tonne for system A, and 21.69 €/tonne for system B. It was also shown that the TPC is highly dominated by the operating expenses while the total capital investment has a smaller impact on the TPC. The capacity is also important for the TPC as lower capacities was shown to lead to significantly increased production costs. When taking the revenue streams from district heating into account the TPC was decreased, in particular for the systems including the heat pumps, where the TPC for system A was 10.26 €/tonne while for system B it was 10.98 €/tonne. In accordance with previous studies it was shown that the economical optimum is closely related to the energy optimum. It was concluded that as system A, the internal liquefaction system, had the lowest TPC and electricity input with and without the heat pump and thus it is the optimal configuration for small-scale CO2 liquefaction.
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A Multimethod Assessment of Carbon Capture and Storage Possibilities in Sweden / Multimetodologisk utvärdering av lagrings- och avskiljningsmöjligheter för koldioxid i SverigeEdvardsson, Albert, Gustafsson, William January 2024 (has links)
Mitigating greenhouse gas emissions from the Swedish industry is central in reaching set up environmental goals on a national level and fighting climate change that results in economic, environmental and social disasters on a global scale. The efforts of mitigating greenhouse gas emissions from the Swedish industry have historically focused on investing in renewable technologies that have no emissions from production. However, to rapidly decrease emissions of greenhouse gases, such as carbon dioxide, could be done by sequestering the gas from point sources at the industry sites and thereafter transport it to geological formations on- and offshore in a process more commonly known as Carbon Capture and Storage. Even so, the Carbon Capture and Storage technology is relatively new and has not yet been implemented on an industrial scale in Sweden. The real potential of Carbon Capture and Storage in relation to helping the Swedish industry in reaching set up national and international environmental goals is therefore unknown. Here we show, via a literature review and performing interviews with stakeholders from the investigated field, that there is a big potential for Carbon Capture and Storage to mitigate carbon dioxide emissions from the Swedish industry and create negative emission rates by storing emissions originated from biogenic sources. Our results demonstrate that there are regulatory, economic, environmental, and social measures that are needed to create a future market for Carbon Capture and Storage and trading with negative emissions. These include evaluating domestic storage sites, changing laws and regulations, and sharing knowledge between countries and companies to create a wider understanding of the technology. We anticipate that our study on the dynamics of a Carbon Capture and Storage market will help stakeholders to identify levers and restraints in the current market so that the transition towards net zero emissions will accelerate, especially when having the national 2045 net zero emission objective in mind. Nonetheless, there is a great need for research to understand such a market, and more specifically to create a consensus between stakeholders on a national and global level when creating it. / Att minska växthusgasutsläppen från den svenska industrin är centralt för att nå nationella och globala klimatmål och vidare bekämpa klimatförändringar som på en global skala resulterar i ekonomiska, miljömässiga och samhälleliga katastrofer. Historiskt sett har åtgärderna för att minska utsläppen av växthusgaser främst legat på satsningar inom förnybara tekniker där utsläppen från produktion är nästintill noll. Däremot behövs åtgärder för att snabbt minska utsläppen av växthusgaser, såsom koldioxid, där detta kan göras genom att avskilja koldioxiden från industriernas punktkällor och sedan lagra gasen på land och till havs genom en process som är mer känd under namnet koldioxidavskiljning och lagring. Trots detta är koldioxidavskiljning och lagring en relativt ny teknik som inte har tillämpats på industriell skala i Sverige. Teknologins verkliga potential för att uppfylla nationella och globala klimatmål är därför outforskad. Studien visar, genom en litteraturstudie och semistrukturerade intervjuer med intressenter inom forskningsområdet, att tekniken koldioxidavskiljning och lagring har stor potential när det kommer till att minska koldioxidutsläpp från den svenska industrin och även när det kommer till att skapa negativa emissioner av koldioxid genom lagring av biogen koldioxid. Resultatet visar att det är regulatoriska, ekonomiska, miljömässiga och samhälleliga åtgärder som är nödvändiga för att skapa en framtida marknad för koldioxidavskiljning och lagring och handel med negativa utsläpp. Dessa innefattar utvärdering av inhemska lagringsplatser, ändring av lagar och regler samt att sprida och dela kunskap mellan länder och företag för att skapa en vidare förståelse av teknologin. Vi förutser att användningsområdet för studien av en framtida marknad för koldioxidavskiljning och lagring kan hjälpa intressenter inom forskningsområdet att identifiera åtgärder som kan verka som hävarm och även hinder för en framtida utveckling mot nettonollutsläpp. Detta då de svenska miljökvalitetsmålen fastslår att nettonollutsläpp senast ska nås år 2045. Däremot behövs vidare studier för att förstå en framtida marknad för koldioxidavskiljning och lagring samt negativa emissioner, mer specifikt behövs konsensus mellan intressenter på en nationell och global nivå för att skapa en sådan marknad.
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