On December 7, 2011, the United Nations Climate Change Conference held in Copenhagen, as scheduled, representatives from 192 countries and regions attended the meeting. After a few days of fiery conference speeches, the conference seemed to turn into a brawl.
While the national emissions reduction targets tug-of-war, how to achieve these emissions reduction targets, will be the future of the country's attention, so carbon capture technology has once again become the focus of media attention.
Technological fantasies such as man-made volcanoes or space mirrors are unreliable, and sequestration technology (CCS), as opposed to carbon dioxide capture, is considered to be saving the planet. We all know that mankind to prevent global warming energy saving and emission reduction, especially to reduce carbon dioxide emissions. Emission reduction path, but coal is the main source of energy, reducing the use of coal is costly CCS becomes an important alternative for those who do not want to change the structure of energy consumption in the country, which is greatly attractive.
People may feel a little weird about carbon capture technology, not realizing that it is, "one of the most popular international cutting-edge and important topics in the field of climate change in the world today, and one that international political leaders have voted to pay great attention to. "At the end of last year, the central bank governor Zhou Xiaochuan, talked about the meaning of "carbon capture", in this regard, the financial industry is promising. According to experts at Zhejiang University, many foreign research institutions have smelled the great temptation to quietly target the domestic carbon emissions market.
The concentration of carbon dioxide in the primitive atmosphere was very high and was not suitable for human survival, the earth solidified the carbon dioxide buried underground (i.e., into coal into oil), thus reducing the concentration of carbon dioxide in the atmosphere, and it became suitable for human survival. Now, on the contrary, by opening coal mines, oil, carbon dioxide buried in the ground dug out, and then released into the atmosphere, the concentration of carbon dioxide in the atmosphere increased, and the greenhouse effect ensued with a series of effects.
In reality, this is a mockery of the Industrial Revolution, with frenzied fossil energy use and retribution. The post-industrial era is the industrial revolution destined to solve these troubles.
Global carbon dioxide emissions were only 2 million tons in 1850, raising to 259 million tons in 2005. Of this, global consumption of fossil fuels is mainly concentrated in the industrial, power and transportation sectors which account for about 63.09% to 72.96% of total global CO2 emissions.
Now, the world's heads of state want mankind in 2050, climate control does not exceed 1850 degrees Celsius 2 degrees above.
Scientists have come up with various ways on how to reduce carbon dioxide emissions in the atmosphere.
The first step is "carbon capture". According to Fang Professor Wang Mengxiang mature chemical absorption method, simply put, is the use of CO2 and a certain degree of water absorption, the chemical reaction between the separation of CO2 gas from the flue gas, scientists have found a variety of excellent performance and environmental protection of the above absorption. There is also a method called "Membrane Separation," in which fossil fuels are burned to produce flue gas when it passes through the membrane during the sorting process, some will dissolve and pass through, but certain passes are "blocked". In order to improve the efficiency of carbon dioxide emissions, scientists have also invented a method of flame cutting with pure oxygen combustion, so that the high purity of carbon dioxide emissions. It is reported that internationally, including China, such as the United States, Britain, Norway, there are many carbon capture pilot projects, including carbon capture efficiency can be as high as 90%.
"Carbon capture" is not the most difficult In addition, "even if the captured carbon dioxide recycling, production of carbonated beverages, and ultimately CO2 or discharged into the atmosphere, scientists need to CO2 safe and permanent preservation," this carbon capture and storage The technology is called the acronym carbon
Capture and storage (CCS) technology.
Scientists are currently thinking mainly in terms of "underground storage," including deep-sea storage and geologic storage. Let me talk about deep-sea storage, you know, the oceans are the world's largest reservoir of carbon dioxide, totaling 50 times more than what is stored in the atmosphere, and playing an important role in the global carbon cycle. The ocean storage of CO2 is mainly ocean storage sites transported to the seafloor through pipelines or ships of CO2, and then injected into the seafloor of CO2, the CO2 in the bottom of the water in the sea is finally carbonized and preserved, this method also has some hidden dangers: "CO2 ships with high pressure to the seafloor in the case of CO2 leakage leads to disastrous consequences, especially seaquakes often. consequences, especially seaquakes are frequent. "
Scientists believe that the more feasible geological storage, CO2 brine layer at a depth of 1 kilometer to 2 kilometers to the ground, the pressure will convert CO2 into a so-called "supercritical fluid" and sulfurization rate is slow, like underground coal oil, in such a state, CO2 is not easy to leak. Carbon dioxide is not easy to leak. "In addition, this rock is structurally better, there is more than enough space to accommodate carbon dioxide and continuity, is it a large enough area? is a saltwater aquifer that is expected to reach ten trillion tons of global reserves, which could store up to 1,000
To date, there have been three successful CCS projects progressing globally***. Carbon dioxide from Weyburn's Midale project landfill through a coal gasification plant in North Dakota, an abandoned oil field in Saskatchewan BP operations Algeria's Sara field project extracts carbon dioxide from produced gas from local inputs into the ground, and Statoil Norway's major oil and gas company has two similar projects in the North Sea. Hundreds of CCS projects are under construction world.
In China, following the Huaneng Gaobeidian project in Beijing, the Huaneng Shidongkou Second Power Plant Carbon Capture Project was launched in Shanghai in July, with a total investment of 150 million yuan, which will be completed by the end of the year, and is expected to capture 100,000 tons of carbon dioxide a year, claiming to be the world's largest carbon capture project for a coal-fired power plant.
, although the CCS technology is still in the experimental stage, its technical ability to receive the desired effect has not yet been confirmed, but the high cost has been called to speak. According to a report published last year by the Massachusetts Institute of Technology, per ton of carbon dioxide capture and processing pressure of supercritical fluid, transporting a ton of carbon dioxide to fill the burial spent $ 30-50 $ 10-20, which is to say that the dollar a ton of carbon dioxide emissions in the atmosphere, the power plant will have to pay $ 40-70, the current price of carbon in the European Union, compared to the $ 8-10 Europe / ton, the number of The median carbon price is also close to the recommendations of the UN Intergovernmental Panel on Climate Change (IPCC).
Fang Professor Wang Mengxiang gave the reporter a simple calculation: for example, burning a ton of coal two tons of carbon dioxide emissions now coal price of 600 yuan / ton, plus the increase in carbon emissions of more than 600 yuan, the cost doubled, and burning a ton of coal to generate electricity 300 degrees amortized to the price of electricity per kilowatt-hour increased by 70% - 90%, while the price of carbon in the production, transportation, and sales of each commodity. Accounting for the increase, and finally will be able to calculate the price of goods with carbon emissions. "With the carbon tax levied, the figure is very substantial." No wonder experts say the global carbon market has the most potential for oil trading after carbon emissions trading will become the largest market in the future.
Meanwhile, national capital has begun to covet the industry, the European Commission has made it clear that the EU plans 8 billion euros of direct investment in the field of CCS technology research, development. "For us, this is both a challenge and an opportunity, at present, many foreign institutions have been targeting the domestic carbon emissions market, such as Zhejiang University has established a technology partnership with the EU, the United States, the United Kingdom Department of Energy, in fact, our domestic cost of carbon capture technology compared to many foreign countries to be low, if you can seize part of the market share is still very promising! But unfortunately, some domestic companies vision. Fang taught? Professor Wang Mengxiang (Youth Times)
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Carbon Capture Technology Introduction
Four main different types of CO2 collection and harvesting systems:
Post-combustion (flue gas separation) separation of fuels in the fuel prior to the separation (hydrogen-rich gas lines) in the oxygen-enriched combustion and industrial separation (chemical cycle combustion). Combustion), each capture technology is characterized by its proven technology in the following table. The selection of the capture system, the carbon dioxide concentration of the gas stream, the pressure of the gas stream and the type of fuel (solid or gaseous) are all considered to be an important factor.
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For a large number of decentralized CO2 emission sources it is difficult to achieve carbon capture, so the main target for carbon capture is a centralized CO2 emission source like a fossil-fueled power plant, a steel mill, a cement plant, an oil refinery, an ammonia plant.
> Separation systems capture CO2 emissions in three main categories: combustion systems, oxygen-enriched combustion systems, and pre-combustion systems.
Introduction to combustion systems
Post-combustion capture and separation is the process of separating the flue? CO2 and N2 in the channel gas. chemical solvent absorption method is currently the best post-combustion CO2 capture method, high capture efficiency and selectivity, reduce energy consumption and cost of the collection.
/> Chemical absorption. France In addition to chemical solvent absorption, adsorption, membrane separation, using a reversible chemical reaction between an alkaline solution and an acidic gas, the flue gas contains not only carbon dioxide, nitrogen, oxygen, and H2O, sulfur oxides (SOx), nitrogen oxides, dust, hydrogen chloride, hydrogen fluoride, and other pollutants but also contains impurities in the presence of the flue gas into the absorber tower, which will increase the cost of capture and separation before entering the flue gas. Pre-treatment is required, including scrubbing and cooling, in addition to water, electrostatic precipitator, desulfurization and denitrogenation, etc.
The flue gas is pre-treated into an absorber, the temperature of the absorber is maintained at 40?60°C, the CO2 is absorbed by an absorbent, usually an amine absorber (e.g., monoethanolamine MEA) with which the solvent is balanced against the moisture in the system, and the solvent vapors of the solvent are removed from the gas, and then the flue gas goes to the scrubber vessel, where droplets of carbon dioxide leave the absorber tower after the CO2 is absorbed in the solvent-rich solvent by heat exchange. is pumped to the top of the regeneration tower. The regenerated absorbent is obtained at a temperature of 100?140°C and slightly above atmospheric pressure water vapor is returned to the regeneration tower through a condenser, while the carbon dioxide leaves the regeneration tower reproducing the base solvent is pumped back to the absorption tower through a heat exchanger and a cooler.
Oxygen-enriched combustion system
Oxygen-enriched combustion system with pure oxygen or oxygen-enriched air instead of fossil fuel combustion as the medium of combustion products are mainly carbon dioxide and water vapor in addition to excess oxygen to ensure complete combustion as well as fuel oxidation products, fuel or air leakage of the inert fraction of all the components of the system in the flue gas cooled in the high CO2 vapor condensate after cooling CO2 content of 80%
98%. This high concentration of CO2 is compressed, dried and further purified into a pipeline for storage. The density is supercritical through a pipeline, where the content of inert gases needs to be reduced to a lower value to avoid an increase in the critical pressure of CO2 that may be due to the flow of the two phases in the pipeline, and is characterized by the fact that the transport of said acidic gas components is also necessary to remove the CO2, after drying, in the pipeline in order to prevent condensation and corrosion and to allow the use of conventional carbon steel materials., Due to the higher CO2 concentration of the oxygen-enriched combustion system, making the cost of capture separation lower, but oxygen-enriched currently supplying the higher the cost of oxygen production by air separation methods, including the use of polymer membranes, variable pressure adsorption and cryogenic distillation.
/>Pre-combustion capture systems introduced
Pre-combustion capture systems have two main stages of reaction.
First, the fossil fuel, the first reacts with oxygen or water vapor to produce a mixture of gases known as syngas) (consisting mainly of CO and H 2, called ? The steam reforming reaction, in which the steam must be carried out at high temperatures, is called "partial oxidation" for liquid or gaseous fuels with O2, while reacting solid fuels with oxygen until the syngas is cooled, and then the CO in the syngas is converted to so-called "gasification" by the steam reforming reaction. ". Carbon dioxide, and produces more H2. finally, the carbon dioxide from the mixture is separated and H2, H2, and carbon dioxide content of up to 15% to 60% of the dry mixture at a total pressure of 2?7 MPa. c?o2 from the gas mixture is separated and captured and stored, and the H2 is used as a gas-fired combined-cycle fuel feed to an intake turbine,? gas turbine and steam turbine combined cycle to generate electricity.
This process, considered in the Carbon Capture and Storage Coal Gasification Combined Cycle (IGCC) power generation methodology, consists of: Separation of CO2 and H2 from the gas CO2 mixture. Pressure change adsorption, chemical absorption of carbon dioxide (CO2 is removed from the gas mixture by a chemical reaction and a reversible reaction occurs in the presence of depressurization and heating, and after combustion with the CO2 alone from the flue gas, etc.), physical adsorption (usually used in the case of a gas turbine and a steam turbine. ), physical adsorption (typically used for separation of gas mixtures at high CO2 partial pressures or high total pressures), membrane separation (polymer membranes, ceramic membranes), and so on.
Carbon Capture and Storage Technology
Carbon Capture and Storage (CCS) is the collection, transportation, and safe storage of industrial and energy sources of CO2 emissions in a place where they are isolated from atmospheric processes for long periods of time. The main three passes of CCS consist of capture, transportation, and sequestration
Carbon Capture
CO2 capture refers to the process of separating, and compressing carbon dioxide from the flue gases produced by the combustion of fossil fuels.
For a large number of dispersed sources of carbon dioxide emissions it is difficult to realize the carbon capture of carbon by separating the sources of emissions from fossil fuel power plants, steel mills, cement plants, oil refineries, ammonia plants. Capture of fossil fuel power plants is the main target of carbon dioxide concentration there are three main, post-combustion capture system capture system oxidized fuel before combustion capture system.
CO2 capture has been used in a number of industrial applications in the chemical adsorption process in a plant in Malaysia, separating the flue gas stream of a gas-fired power plant for the production of urea at 0.2 x 106 tons of CO2 per year. Physical solvent method coal gasification plant in North Dakota, separated from the gas stream, separates 3.3 x 106 tons of CO2 per year for the production of synthetic natural gas, captured CO2 for enhanced crude oil recovery projects in Canada.
Low-carbon transportation
Transportation of CO2 by compressed CO2 pipelines or transport vehicles for storage was put into operation in the early 1970s in the United States, with more than 2
500 kilometers of CO2 pipelines, through which about 40 × 106 tons of CO2 are captured for enhanced crude oil recovery and stored in each
Carbon sequestration
Carbon sequestration
The CO2 is transported to Texas and reaches storage places such as geologic structures where CO2 is injected into underground brackish water aquifers, abandoned oil and gas fields such as coal mines, geologic structural formations, or deep below the seabed or sea floor.
This process involves a great deal of research, development and general application of technologies in oil and gas exploration and production, such as pumping CO2 into the ground, perforating CO2 at the bottom of wells or sieving it into rock formations.
BR/> In addition to the reinjection of CO2 into oilfields for enhanced recovery, the injected CO2 can be recovered in coal seams as coal bed methane, a process commonly referred to as Enhanced Oil Recovery (EOR) and Enhanced Coal Bed Methane (ECBM). There are three industrial scale (greater than 1 x 108tCO2/A) projects that have adopted this technology:
Carbon's Sileipu, North Sea Nel (SLEIPNER) project, the Weyburn project in Canada (Weyburn's) and the Salah (Shara) project in Algeria. Introduction of transport technology
CO2 transportation, the most viable option is the use of pipelines
Pipelines are a mature market for the technology, CO2 gas compression can increase the density, which can reduce transportation costs, but also the use of shipping CO2 insulated tanks mounted on the tanker for the transportation of liquid CO2 is, in some cases, from an economic point of view, more attractive, especially when there is a need for Long-distance transportation or CO2 shipments overseas, but due to the limited demand in this case, and consequently the transport scale is small. Road and rail tankers are technically feasible for the procedure. However? , in addition to small-scale transportation, such transportation systems, pipelines and ships compared to the current no economic unlikely for large-scale transportation.
The United States and other countries in the pipeline transportation technology is already very mature, and need to solve the problem of how to reduce transportation costs.
The cost of transportation depends largely on the length of the pipeline, the diameter of the pipeline, the cost of capture (including compression) is very high, and therefore the transportation cost is low in proportion to the total cost. As long as the capture and storage costs are low, or in order to obtain some other benefits (e.g. enhanced oil recovery) many countries transport CO2 over long distances where the transportation costs are high.
For example, the United States uses the Sheep Mountain (Goat Mountain) Pipeline, the longest pipeline, for the long-distance transportation of high-pressure liquid CO2 for enhanced oil recovery, transporting CO2 from southern Colorado to the Permian Basin in Texas, a distance of 65 miles. 's Permian Basin, a distance of 656 kilometers.
Introduction to carbon sequestration
Carbon sequestration is the process of capturing, compressing and transporting CO2 to a designated site for long-term storage.
Currently, the main archives are geological storage, marine storage and manganese carbonate ore storage. In addition, some industrial processes capture CO2 during the production process and store small amounts.
However, emissions from ordinary power plants, untreated flue gas contains about 3% to 16% carbon dioxide, the compression rate is much smaller than that of pure CO2, the carbon dioxide content of the compressed flue gas coming out of coal-fired power plants is only 15% of the stored 1 ton
CO2 requires about 68 cubic meters of storage space under such conditions, therefore, only from the flue gas Separation of carbon dioxide, in order to adequately and efficiently underground treatment.
Underground CO2 sequestration to prevent CO2 leakage or migration requires sealing the entire storage space, therefore, it is also important to choose a suitable sealing cover layer with good sealing performance, which can play the role of a "talisman" to ensure long-term CO2 storage underground.
The more effective way is to use conventional geological confinement formations, including gas fields, oil fields aquifers for the first two, because they are familiar with their structure and geological conditions based on part of the human energy system, so using them to store carbon dioxide is much more convenient and cost-effective;
Aquifers, because it is very popular, and therefore has a very large potential for carbon dioxide sequestration. potential for carbon dioxide sequestration
Depending on the carbon sink, the way the carbon sinks go into geological storage, ocean storage, carbonate ore sequestration, and industrial fixed sites and modes, each of the sealing modes is different in terms of technology, and their state of development is tabulated below
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- The current state of the art of the development of
Carbon Capture and Sequestration (CCS) technology,
- The current state of development of CCS technology,
- The current state of development of CCS technology,
CCS technology, due to its consistency with the basic structure of the existing energy system under the close attention of the international scientific community and industry, by the constraints of energy resources, the technology is of particular general concern to industrialized countries, the United States of America's close attention to the European Union and Canada has developed a technology research program to carry out research on the theory of CCS technology, testing, demonstration and application, according to the International General Energy Administration statistics, as of today, the global total of carbon capture 131 commercial projects, capture 42 R & D projects, geological deposits demonstration projects 20 61 R & D projects, geological burial, the more well-known Norwegian Sleipner project Weyburn project in Canada and Algeria in
Salah project.
BR /> In recent years, Europe and the United States began in November 2002, the U.S. Department of Energy, American Electric Power & Energy (AEP) peak power thermal power plants as the main storage object of the test underground storage of carbon dioxide emissions. plant at the mouth of West Virginia to carry out research projects on methods of geological storage of carbon dioxide;
In February 2003, the European Commission funded a research project on carbon dioxide storage to carry out the nature of CO2 reservoirs in Denmark, Germany, Norway and the UK to store emissions from hydroelectric power plants; there are several demonstration projects around the world of CCS pilot projects for 250MW scale IGCC coal-fired power plants
.The World Carbon Sequestration Leadership Forum held in Melbourne, Australia on September 14, 2004 confirmed that in 2010, 10 experiments were conducted to strengthen international cooperation to promote scientific and technological projects, and that the participating countries showed strong interest in international cooperation on carbon sinks
Projects and experiments have demonstrated that
The CCS technology is a cutting-edge technology with a great potential to reduce CO2 emissions.
In this case, a win-win situation will be realized in economic development and environmental protection.
In the U.S.A., for example, the U.S.A. started the official launch of the CO2 storage research and development program under the auspices of the U.S. Department of Energy in 2000, while the research on terrestrial ecosystems (forests, soils, vegetation, etc.) as the main research areas include geologic sequestration and sequestration of carbon dioxide in oceanic storage, and developed a detailed technology roadmap for more information, please refer to the following table
In 2005, 25 field trials for injection, storage and monitoring of CO2 in underground structures were conducted in the US and have entered the validation phase.
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Prospects and Actions for the Development of Carbon Capture and Storage Technology in China
China's national conditions, stage of development, and energy structure dictate that carbon capture and storage (CCS) technology is an important strategic choice for China's climate change, and the most promising market for carbon capture and storage in the world. Although the technology is still in the research, development and demonstration stage, but the domestic universities, research institutions and enterprises of the positive action and progress, CCS center construction feasibility study is also being carried out a comprehensive understanding of the CCS technology itself has the problem of China is of great significance to improve the R & D capacity to cope with climate change ability and competitiveness ...... />China's response to climate change carbon capture and storage
"The entry into force of the "Kyoto Protocol" for mankind **** with the response to climate change into the increased hope, but is still relatively simple, the use of renewable energy and other technological means to reduce carbon dioxide emissions Improving the efficiency of energy use, energy-driven modern society, fossil fuels will continue to be the main source of energy supply carbon dioxide and other greenhouse gas emissions are under enormous pressure to stabilize the concentration of greenhouse gases at a certain level, the need to take a comprehensive in this case, the IPCC Carbon Capture and Storage technology to reduce emissions in order to *** with the flexibility to deal with the emission reduction of greenhouse gases.
The so-called carbon dioxide, timely collection collection and storage measures to produce carbon dioxide from the combustion of fossil fuels, medium-term and long-term storage in natural underground reservoirs to reduce carbon dioxide emissions into the atmosphere This technology not only implies an important option for global greenhouse gas emissions, and its fundamental measures to reduce the concentration of carbon dioxide in the atmosphere, to achieve the use of near-zero-emission energy.
In recent years, China's rapid economic growth on energy demand is increasing greenhouse gas emissions have ranked among the world's leading, while China is a profound impact on climate change in developing countries, extreme weather events, the frequency of coal-based energy and secondary energy structure of thermal power plants, carbon capture and storage is a very broad application prospects in China, China's carbon emissions reduction and responding to climate change will also become an important technology option.
Chinese CCS: in the R & D stage
From the 1970s, China began to pay attention to carbon dioxide enhancement of oil recovery research and international advanced practices, compared with the former carbon dioxide capture CCS research and development in China, is still only applicable to some high-purity carbon dioxide, and it is easier to capture refining, ammonia, hydrogen, natural gas purification and other Carbon from industrial production processes. The overall appearance of carbon dioxide capture and storage is still in the laboratory stage, but mainly by post-combustion capture, industrial applications are mainly to improve oil recovery national major issues.
However, in recent years, China has done a lot of work on CCS research, since 2003, the Chinese government participated in the Carbon Capture Leadership Forum "973 Program", including the "863 Program" for CCS. in addition, Huaneng, Shenhua and other large companies are planning to research CCS. In addition, Huaneng, Shenhua large companies planning, research, and demonstration of CCS July 16, 2008, China's first coal-fired power plant carbon capture demonstration project - Huaneng Beijing Thermal Power Plant power plant carbon dioxide capture demonstration project was formally completed and put into operation, marking the first time that the carbon dioxide gas emission reduction technology is applied in the field of China's coal-fired power generation.
The first CCS Center as a developing country, the Coal Information Research Institute (CIRI) has cooperated with the International Energy Agency (IEA) to establish the "CCS Center" which will actively promote the development and demonstration of CCS technology in China, as well as the transfer of technology and the sharing of information***.
The reality of the challenges faced by CCS
CCS as a basic technology method of greenhouse gas emission reduction has great potential for development, but its application will greatly change the traditional forms of energy production, affecting the economic costs; geological structure, marine ecology, human health, the Earth cycle of the system has great uncertainty affecting the living environment of human beings, the application will also change the existing perception of the existing system, the existing system of the human environment, the application will also be a major challenge. Change people's existing perceptions, existing laws, regulations and policies, and social tolerance. Problems facing CCS:
> The cost is too high. It is currently estimated that the application of CCS will increase the cost of power generation by about $0.01-0.05/kWh, more than 20% of energy consumption, which will hinder the development of CCS
Health, safety and environmental risks. The application of CCS will likely be associated with the risk of pipeline transportation, geologic sequestration leakage, and the risk of carbon dioxide injection into the ocean caused by the risk that these risks will affect human health, safety, and ecology Unforeseen potential risks of CCS have been a major concern to society that is unacceptable, but also impede the development of CCS.
Lack of relevant laws and regulations, lack of an appropriate legal framework to facilitate the implementation of geologic sequestration, and lack of consideration of long-term liabilities.
Lack of awareness of issues such as matching of sources and sinks, risk assessment and monitoring. Awareness of the shortcomings of CCS; Capture, Transportation and Storage (CTS) technology itself, which has yet to be studied in depth; distances from the main sources of CO2, also to better understand and establish storage points and cost curves for Capture, Transportation and Storage (CTS); the need for improved estimates of storage capacity at the global, regional and local levels, in order to better understand the process of long term storage, flows and leaks, etc.