The Importance of the Tar Sands - Term Paper Example

TAR SANDS Executive summary Tar sands occur in tailings and they are sometimes referred to as oil sands. There is noclear distinction between the two. The concept of oil sands or tar sands is well understood from Canada ( Cerclay 2) which has many industries that mine the resource. Processes have evolved over time with new technologies being discovered on how to effectively mine the oil. The bitumen go through a series of processes before it can become useful. The whole process is known as upgrading (Nikiforuk 29). Scientific method being developed by scientists currently is the solvent process. Suitable solvents are used to absorb the impurities and leave no traces in the bitumen. Figure 1 (Cerclay et al 57) Figure 2 (Nikiforuk 20). Future technologies that use steam by injecting it to the ground is underway the method is almost completed and has been used in some industries. Steam is preferred to some of the inventions since recycling is done and water conserved. In general, the other convention oil wells are easier to mine than the numerous tar sands (Cerclay et al 57). Production effectiveness is compared between the scientific extraction and the traditional methods. Though most effective, the scientific methods need expertise to carry out the operation. These tailings have been found to affect the environment and appropriate measures are being taken to curb the problem. This can only be achieved if research is done and more effective technologies are invented. INTRODUCTION Mining of tar stands entails various processes. The general name given to it is refining. The crude tar sand is then processed in a way similar to the oil wells but extraction becomes rather complex. The processes involved in recovery tar sands are mainly extraction systems and thereafter separation. It aims at separating the bitumen from the crude (Nikiforuk 28). Upgrading is needed before refining the bitumen. Numerous scientific methods or technologies are used. Recovery technology is the very fast method to be depending on viscosity, grade and depth of the area. In-situ technology is used in deeper and less warm resources. The tar must be less viscous for this technology. Other methods include stream injection, solvent vapor. Cerclay (34) recommends Cold Heavy Oil Production with sand chops. Tar sands exist in ecosystems known as tailings. To manage them, ponds are normally used. The tailing then settles for 3-5 years. The ponds keep the tallying from entering the watershed. BACKGROUND INFORMATION Tar sands or oil sands as some countries call it are usually a mixture of water, bitumen, sand, clay and it is black heavy asphalt –like hydrocarbon. The bitumen from them can be developed to form synthetic crude element of the oil. This is further refined to produce asphalt, jet fuel and other chemicals like gasoline (Brown p. 12). Some tar sands are lean and their mineral matter consolidated whereby the sand grains become tightly cemented with the chemicals. Lessons can be learned from the existing technologies used in the process. They can be further modified to make the process of synthetic oil extraction more effective. Most of the oil in the world is found disguised as tar sands. Larger deposits of these resources lie in Canada in a place known as Alberta. Venezuela and Middle East countries also have these resources in large quantities just like Canada. Significance of the study Scientific methods and microstructures are advantageous compared to the traditional methods like heating and distillation. The report will aid the miners to more effectively extract large quantities of tar using less complex methods. The study also brings out clearly the importance of the tar sands. All the processes tar sand oil under before getting crude oil is highlighted in this work. The new and scientific methods stated in this paper are important since it is very efficient. Ionic method is very simple and can reduce the load of having to put up with the task of excavation. Normally the use of trucks in mining areas impact negatively on the environment. Any new development in this sector is a remedy to environmental destruction. There are new technologies which are being developed and have been tested and found effective. The report covers the solvent method. Ionic separation by the use of cations of ILs is a big step in the technological inventions. This study brings out clearly the type of materials used in the extraction. Steam is a major component used in vapor method. Water is used in almost all the methods, be it ionic on mechanical methods. Hydrocarbons like heptane are used due to their stability and that they boil at low temperatures. Most people in the world are not of the emissions of the tar sands. The emissions are currently the chief producers of greenhouse gas. Little legislative attention has given to the industries mining bitumen from the sand or oil sands. If care is not taken then in the next decade, their emissions will overwhelm the atmosphere. They need to use the appropriate technologies that are eco-friendly Opening pit method It is sometimes referred to as ex-situ extraction. This method was introduced in about a decade ago. It has evolved from the use of bucket wheels to use of draglines connected to strong plants supported by many conveyer belts (Nikiforuk 20). It improved the mining efficiency and costs were significantly reduced. It uses shovels that are powered by electricity and hydraulically supported. The shovels excavate tar sands which are then loaded into huge trucks, with carrying capacities of 320 tons in each trip. The trucks transport the load to the extraction plant. Alternatively it can be piped to this point. The mixture is piped into basins or tailing ponds to settle. The separation then takes place and the extracted bitumen are sent to be upgraded further. Bitumen at this stage gets upgraded to get a crude oil that is synthetic in nature (Brown p .26). One limitation of this method is cost effectiveness. The costs of transportation to the separation center can be high. The material used here is mainly water. Fig 3 (Brown p .26). Upgrading bitumen This is needed to improve hydrocarbons in the bitumen so as improved and make the product gotten valuable. This process has four steps. The first one being coking that removes carbon, distillation to remove all the impurities. Conversion process needs catalysts to take place while hydro-treatment that removes sulphur and the traces of hydrogen present in the mixture. The quality of upgraded bitumen depends on how effective the entire process of separation was done. Figure 4(Cerclay 45) Hot water treatment of bitumen Three steps are involved in this process namely: scavenging, condition and separation. Conditioning is the initial stage. It is of two types. In the first one, the already mined tar is pumped in a water mixture and caustic to a drum that provides the conditioning. It is done at room temperatures for particle reduction and initial bitumen digestion. The end product is slurry and is screened so as to send undigested materials and the huge lumps into the separation cell. The new method known as hydro transport, tar sands become crushed immediately at the site and pipeline moves them to a well built extraction plant (Cerclay 45). Separation cell functions as the settling medium or rather vessel. The sand sinks to the bottom, tailing and the less viscous bitumen and skimmed (Cerclay 45). Additional removal of the bitumen takes place in the scavenger cells. A sheath of water is absence between the tar and the sand particles. Therefore a strong bonding is formed between the two indicating a strong energy needed to separate them. The other methods of extraction are the in-situ. This involves drilling and pumping of the more volatile tar sand. The various are modes are: Steam assisted gravity drainage Two horizontal wells are drilled. One well is dug at the most bottom part within the formation and the other just 5 meters on top of it. Steam is injected using upper well into the reservoir. The bitumen is then melted by the heat that the steam produces. The steam used enables the gravity to assist in the flow of bitumen into the lower well (Nikiforuk 45). Apparently bitumen is pumped to the open surface. This method is cheaper compared to the open site method. The rate of producing oil is relatively high compared to other methods. Scientifically, gravity and steam are adopted in this method. Other methods, like the cyclic steam stimulation adopts the use of steam. The well sits for some days to allow enough heat into the tar sand. It heats the bitumen and then pumped out. Pumping can take up to a week. If there is low production, the well undergoes many cycles of soaking, injection, and production. The series of activities goes on until the cost of production is considerate. The vapor extraction method also uses steam. It is similar to other steam methods only that hydrocarbon solvent dilutes the bitumen in the upper well. It is injected into the well. Its advantage is that energy is used efficiently and bitumen partially upgraded to crude oil in the sands. Cold flow production is achieved pumping without steam. Pumps known as progressive cavity are used (Larter et al pg. 36). This method is suitable in areas having their bitumen less viscous and it can pump easily. It is the cheapest method. Its limitation is the task of disposing large sand quantities. The vapor method becomes more scientific since steam pressure principles are used. The bitumen conveyed to surface through pumping is a froth. This is processed into a stripper where air bubbles are removed and bitumen froth transferred to storage tanks. Particles of the sandy sediments at the bottom and soon pumped directly to a system known as tailings processing. Tailing is occasionally maintained using ponds. The sand sinks to the bottom and settles after a period of three years Toe to heel air injection It is still new in the mining industry. This method injects air into the vertical well then combines it with a production well that is vertically placed. At the begging of the process, the horizontal well is heated using steam to melt the steam (Larter et al 46). The heating cycle takes three months at the reservoir and on completion the steam is immediately cut off. Air is then forced into the vertically placed well and combustion reaction follows suit. As the reaction proceeds, bitumen pours vigorously into the horizontally laid well and comes out to the surface by natural pressure. Combustion takes place with a temperature of 400c partially upgrading the oil underground. Heating makes asphaltine found in the oil to remain as coke used as fuel for the combustion. Water is used in the initial steaming stages but returned back where it is treated and reused in the process. This technology after being tested in some parts of the world like Fort Table 1. (Cerclay p. 230) Mcmurray has been soon been adopted around the world (Larter et al 56). As seen in this process, it does not require much material; steam and water are the main drivers of the process. Extraction from the sand using ionic liquids A work completed in the last 18 months in a place known as Penn State, it has found out that some ionic liquids are able to separate the bitumen in the tar sand to get a crude oil which is refined and the desired final products gotten. This separation is done using solvents that are non-polar that lowers viscosity of bitumen and makes the separation much easier (Cerclay p. 230). This process is found to take place under standard room temperatures and less waste or no wastes are totally produced. The bitumen recovered is very clean and detective. Mineral fines that can be detected by IL ions are not found. The ions do not contaminate the oil. The sand comes out uncontaminated after the residual irons are removed through little washing in cold water (Cerclay p. 200). The ILs have unique properties allowing to be easily separated from the water which is then recycled. ILs has an outstanding property about its stability. It is chemically stable and its thermal stability is great compared to most chemicals. The chemical also has very low to almost null flammability. Its vapor pressure is very low and negligible. This makes it attract solvents in chemical reactions and other processes that are chemical in nature. In this process, a versatile ILs is used. It has a 1 - alkyl-3-methylimidazolium cations (Sheppard et al 37). When oil sand is stirred using imidazodium IL then toluene added at room temperatures, different three layers will appear. At the bottom is the sand layer and clays, in the middle is the ionic IL with bitumen in small amounts while at the top is toluene plus bitumen. The top layer is then easily removed by the use of a pipette. All bitumen are eventually removed with no fine particles detected. Water is never used in the separation stage but small amounts are used in the event of separating the chemical residue from the bottom layer components that contain sand particles and some clay. Using the ionic approach, a bench can be built then a special unit scale is placed on it. Then tar quantities measured in kilograms can be separated. Solvent processes This process uses low boiling solvents, usually hydrocarbons. They include ethanol, heptanes and cyclohexane. They are mixed in the extract and the countercurrent three stage washing is used. Thorough draining followed by settling takes place for about 30 minutes. The remaining steps recover the used solvent from the entire process (Larter et al 67). This process requires less transportation by much science is applied. A person needs to know the laws and the mechanisms behind solubility of the solvents. The solvent used is usually perfect in its adsorbent characteristics and must be stable. The role of tar sand on global warming Public protest Figure 5. (Sheppard et al 33) Tar sand development emissions are bound to have three times more intensive green gas than the usual oil. They are the fastest growing greenhouse pollution in the world. The emissions have doubled for the past two decades. Predictions are that they are to double in emission by 2020. (Sheppard et al 33) states that regulations have not been put in place on these companies. As a result they are not accountable for their activities and have commercialized the industries. The industries should instead incorporate cleaner productions in their planning processes and the life cycle analysis of the products should be used (Larter et al 89). The land is greatly affected by the mines. Excavation leads to dereliction of the land. In situ method in particular uses steam that is injected directly to the ground. Therefore the geochemical nature of the soil is changed. Open pits dug have led to deforestation, habitats destroyed and wildlife affected. Sludge in form tailings is very toxic (Larter et al 78). They are kept in the created lakes and ponds for the indefinite storage of the wastes. The waste finds their way into the natural water system through seepage. Aquatic life that depends on water has been the victims of this form of pollution. Release of toxic gases like sulphur dioxide contributes to acidic rain Future developments “Top –down combustion” as described by (Sheppard et al 34), where combustion is initiated and the reaction maintained by injecting air at the reservoirs top. The oil is heated and mobilized into the horizontally placed wells aided by the gravity. Another development is the pressure pulse flow enhancement technology. This is a recent technology that will use large-amplitude and energy waves of low frequency that enhances the flow rates (Sheppard et al 34). Eventually nuclear energy has been recommended in the production of steam as well as electricity in the recovery of tar sand and reducing the emission of carbon dioxide. Conclusion In a nutshell, tar sand oil is mined while the other oil found in the numerous wells underground is extracted. Traditionally, it entails clearing the ground and digging out so that sand that has a considerate amount of oil tar is carried away for further processing. Mining is more complex than the usual extraction of the oil present in the wells. Technologies used in this were adopted from the ones previously innovated while the current ones are simple but need skilled scientists who understand the chemical processes. Materials used in extracting tar sand range from water to some other solvents which leave no traces in the final product. In closed methods or in-situ methods, combustion takes place which is much more scientific since the principles of pressure is used. The most commendable is the ionic method. It uses ILs solvent which has unique properties. It is highly stable, less flammable and at room temperatures attracts solvents. This method has been developed to have a scaled container put on top of a table and loads of tar sand added to it. Eco-friendliness of this technology has been making it become more popular among oil sands producing companies. Works cited Brown, Chrales E. World energy resources. New York City: Springer, 2002. Print Cerclay, Hilda. Tar sands: The Golden Calf. Bloomington: iUniverse, 2012. Print. Larter, S et al. “The Origin, Prediction and Impact of Oil Viscosity Heterogeneity on the Production Characteristics of Tar Sand and Heavy Oil Reservoirs”. Journal of Canadian Petroleum Technology. 47. 1 (2008): 1-10 Print. Nikiforuk, Andrew. Tar Sands: Dirty Oil and Future of a Continent. Vancouver: Greystone/David Suzuki Fdtn, 2009. Print. Sheppard, Mary C. Oil Sands Scientist: The Letters of Karl A. Clark. Edmonton: University of Alberta, 2009. Print. Read More