IntroductionOn thissection there will be mentioned the aims and the objectives of the project andthe research that has been done in order to complete the study.
Aimsodjectivesthis studyis aiming to show the advantages anddisadvantages of current Carbon Capture and Storage technologies and theireffectiveness at reducing the disaffectsof anthropogenic climate change.Theobjectives are to examine the Carbon Capture and Storage technologies, accordingtheir positives and negatives. Also to identify the best way to record the anthropogenic climate change.
BackgroundMost of the environmental problems start during the industrialrevolution, since then they have been increased dramatically. In addition to thatduring the last 200 years the human population have been growth rapidlyfrom 1 to 6.5 billion. Before the IndustrialRevolution in the 19th century, global average CO2 was about 280 ppm. CO2 is one of the mostnotorious greenhouses gases produced from human activity.
The consetation of CO2 in the globe is increasing, that phenomenon hasbeen noted over the years from the environmentalists worldwide. From 1995 to2001, average global CO2 emissions increased at a rate of 1.4% per year. Whilethis increase is slower than the increase in use of primary energy, it ishigher than the increase in CO2 emissions over the past 5 years. There is sufficient evidence toshow that human activities have contributed significantly to the gradualwarming of the Earth over the past 50 years. According to the AustralianGreenhouse Gas Inventory, in 2006, 576.0 million tones CO2-equivalent (CO2e) werereleased from human activities. Carbon dioxide was the most significant ofgreenhouse gases in Australia’s inventory, making up 74.
3% (427.8 milliontonnes) of total CO2 emissions. Electric power generation is the greatest contributor to CO2 gas emissions , asit produce approximately 50% of the total CO2 that are produced. Anotherhuge factor of CO2 emitions is the transport sector. Moreover,on December 2017, the average CO2 level at Mauna Loa, Hawaii, was at 406.
75ppm, whichwas 1.61ppm higher than the average for November 2016 5, although the biggestever increase over the period of a year was from 2015 to 2016. In addition, itwas very different from the CO2 levels at the period before the IndustrialRevolution. While some of the increase in CO2 levels can be attributed to the ElNiño phenomenon, a significant portion of it was due to activities of humans. Business-as-usual emission scenarios forfossil fuel emissions suggest that atmospheric CO2 could peakin 2,250 AD at ?2,000?p.
p.m. CO2 valuesas high as this were last seen in the Triassic around 220–200?Myrs. Somestudies claim that greenhouse gas emissions have decreased recently.
Although thosestudies have consider only the emissions for the generation of energy accordingto the estimations that each country made. Changes in land use, including theeffects of deforestation and the loss of land have not considered. The wordssensitivity of the correlation between increasing atmospheric CO2 levels and climate change has spotan increase in the research and development for techniques that produce energywith clean methods and that is renewable also. However, the fast tempo which temperature at the globe is increasing, will demand drastic actions forreduction in CO2 emissions, that means restriction of the old ways for energy productionand establishment of new clean energyproduction ways that are also renewable. In order to combat the rising levelsof CO2, Carbon Capture and Storage (CCS) technologies have gained theattention of researchers and environmentalists worldwide. This study will investigatethree of the most promising CCS technologies that will help at the reduction ofthe anthropogenic climate change: (1) biomass carbon sequestration, (2) geographical sequestration, (3)mineral carbon sequestration. BiomassAninteresting way to isolate carbon would be using biomass.
Biomass a materialthat produced form living organisms. Specifically, the biomass is working as a storage forenergy as it uses H2O +CO2 +Solar Energy = Biomass + O2. As it can be understood there is no need forlarge amount of human recourses as the primary need is Sun light. Crops are consideredgood option for the production of biomass. Although there would be need forlarge areas of planting fields in order to produce sufficient amount ofbiomass. On the other hand the sources of machines and generally theagriculture reassures would produce significant amount of CO2 in that scale.
So the benefits of the biomasswould canceled with the CO2 emission that the agricultural sources wouldproduce. The use ofalgae for producing biomass would be more preferable in compare to the crops asthey do not demand cultivable land. The algae consume large amounts (80% to 99%under optimum conditions) of CO2 as they grow and produce O2. There has been calculatedthat an algal pond of 3600 acres would effectively capture 80% of a typical200MWh natural gas-fired power plant’s CO2 emissions during daylight hours,assuming an algal areal biomass productivity rate of 20g dry weight per squaremeter per day. From all the above it can be understood that the Algae is themost suitable method for CO2 capture than the crops.Another efficientway to store CO2 in a stable form of carbon is the biochar wich holds 90% ofcarbon.
Its produced by pyrolysis whichis the direct thermal decomposition of biomass in the absence of oxygen, which produces a mixture of solids, liquid,and gas products. Also pyrolysis creates gases such as hydrogen and methane,which are combustible fuel. geologic sequestrationGeologic sequestration demands 3 processes:capturing CO2, transporting CO2 , and placing theCO2in a geologic formation forpermanent or semi-permanent storage. The carbon dioxide is placed into thegeologic formation using the system of injection wells.
An injection well is like an oil well or waterwell, despite that instead of pumping oil or water out of the ground, CO2 is injected into the well.Injection wells are also used for the disposal of various types of wastes andto enhance oil recovery in some areas. Thereare studies that are suggesting to use deep saline aquifers that are deeperthan 1km from Earth’s surface, deeper than the freshwater sources, as a storageplace for the CO2 thatwould be liquefied. The mechanisms for storing or isolating CO2 at aquifers are the followings, (a) Dissolution ofCO2 into the aquifer water, (b) Hydrodynamic trapping of a CO2 plume, (c) Occurrence of geochemicalreactions between CO2 and the aquifer fluids or rocks to form stable solidscarbonates. The geochemical reactions of CO2, aquifer fluids and rocks areproceeding at a relatively slow pace. Although it has been discovered that highconcentrations of silicates in aquifers are accelerating the geochemicalreactions. There are 2 types of aquifers the freshwater aquifers and the salineaquifers. As it can be understood thefreshwater aquifers are vital as they are drinking water and they are extremelyprotected.
Also the freshwater aquifers are shallower than the saline ones,another factor is that the freshwater cannot hold high pressure as the salineones so they are not practical for efficient storage CO2 . In conclusion freshwater aquifers are not good location for geologicalsequestration. On the other hand the saline ones are deeper and there is moreknowledge on that technology due to the injection technology. Also due to theirdepth are making a better sealing with the outer surface so they are moresecure. However, their high level of availability makes them useful as they cansource big volume of CO2. Apart fromthe aquifers there are also depleted oil and gas field that with the techniqueof Enhanced Oil Recovery (EOR) they can extract most of the amount of oil andgas that is trapped in the fields, which in other case it would be unrecoverable.
By that way CO2 would be stored as the injected CO2 will reach with the oil.Also those fields have proved their reliability due to the fact that they werestorage or oil and gas for thousands to millions of years. Another importantfactor is that they are well known as they have been studied on the past andthey are capable of storing huge amounts of CO2 Mineral carbon sequestrationMineral carbon sequestration is the reaction of CO2 witha compound that gives a thermally stable and poorlysoluble carbonates at ambient conditions. Those carbonates containthe following elements iron, magnesium and calcium. From those elements mainlythe magnesium silicates and the calcium silicates are the most common forcarbon sequestration, those materials are also well known around the word. Onthe other hand, iron has a great value for making steel so I does not appliesfor carbon sequestration use.
Although, Australia seems to differ on thatmater as it is known to have big amounts of low-grade magnetite which can beused for sequestration.In our days precipitated calcium carbonate is produced form carbonatingcalcined limestone which is a calcium oxide but this procedure produce amountof CO2 that is similar to the amount needed for the calcium carbonateformation. As it can be understood this procedure would create a viciouscircle.
Also it would be impossible a batch of calcined limestone to carbonateentirely. So insead of beneficial this procedure would be problematic as Iwould release CO2 to the environment.Apparently there is greatvalue at the steel slugs, the iron slugs and the materials that based to cementas they have very high comprehensiveness at oxides of magnesium and calcium. Additionally,the slugs of steel have been proved to be able to carbonate very easy withoutthe need of high pressure and temperature this has been also proved from W. Huijgen, G.-J.
Witkamp and R. Comans that calcium conversions of over 70% are possible at relatively mild processconditions (d<106•m, T=200°C, O2=10bar, t=15min) without any furtherpretreatment or addition of chemicals. Furthermore there is high availabilityof slugs and it is also predicted to be a rising of the production of steel andiron slugs in a global scale. This method is very promising as it allowsbenefiting the slugs for capturing CO2 by carbonation. Last but not list itwould be also beneficial as it counteract the steel industrial wastes The key to climate change Using the chart above wecan list the biomass as the method with less Carbon storage capacity but atshort period of time, the injection of CO2 underground has less storagecapacity in compare to mineral carbonate although it demands less time toachieved which is still significant. The mineral carbonates are able to storemore CO2 but the demand plenty more time.
Although the mineral carbonsequestration is a safer approach as the product is solid at ambient conditionin compare to the underground injection which run the risk of licking. CO2licking will cause big damage to the area around the leak. As it has been notedpreviously all the methods for CO2 sequestration have their own limitations.Although there are moreobstaclesto the application of those methods. Firstly the techniques that are used forthe production of electricity are interfering with the cost for the CO2capture. For example courtiers that are using natural gas, black coal and browncoal to generate electricity are producing plenty of CO2, in order to capturemost of it there is need for large and costful chemical facilities. Also theplaces that injection well would take place might be in a large distance. As aresult of the factors the cost building the facilities and sequestration CO2will be significant, resulting the method of geologic sequestration to berestricted to certain areas.
Also most of the modern power plants have been builded without the scopeof including carbon capture equipment and I would be costful to do the appropriatemodification so they can be able to capture it. Apparently as the amount of captured CO2 would raise, the cost tostorage it would also rise as the cheapest locations would have been filled andthen there would be need for more locations. With the current data it is not easy the cost for carboncapture and storage to be estimated The target for reducing theCO2 emittions can be achieved easier by using the carbon capture methods insteadof trying to replace all the existing power generation method with renewable asthe renewable are still on an early stage and they are not capable to cover the needs of the entireplanet. During the first steps of the transaction to renewable energy sourcesthe geological sequestration would be more efficient in compare to other carboncapture methods as of its cost and the fast delivery of results.
Many oilcompanies can also get involved as they can use CO2 in liquid and high pressureform as a mechanism to extract any trapped oil or gas. Furthermore as the cost forgeological sequestration would raise due to the decease of sedimentary basins availability,the mineral carbon sequestration will be the best available solution as themineral carbon sequestration forms inert carbonates that are easy and safe fordisposal. There is need for the mineral carbon sequestration to be developedand use slugs from iron and steel instead of natural oxides and silicates dueto their low availability Despite the fact that biomass carbonsequestration needs more time to give sufficient results it can be an efficientapproach in long term without interfering to other environmental actions.Wisely it would be important biomass carbon sequestration methods to develop parallelto mineral carbon sequestration and geological carbon sequestration.