I received my Master’s degree in chemical engineering from SU, USA. I worked as a writer and researcher for Fortune 500 company clients.
The Current Scenario
In India, the annual CO2 emissions fell by 30 MTCO2 (1.4%) in the fascial year 2019-2020 (CarbonBrief 2020). This is because of a fall in the economy and a slowdown in activities arising from the outbreak of the coronavirus (COVID-19). However, we cannot deny the fact that carbon emissions have been increasing over the years. The carbon emissions in 2018 were 123 Mt CO2 that increased to 132 Mt CO2 in 2019 in India (CarbonBrief 2020).
According to iea.org statistics report, the total amount of carbon emissions resulting from gas and oil operations is presently 5200 million tonnes of carbon dioxide. This accounts for 15% of the total energy sector's carbon emissions. According to the reports, these emissions came from various sources of the gas and oil industry, including processing and collection of gas, conventional and unconventional production, and from its distribution and transmission to end-use consumers.
Future scenarios depicted by the International Energy Agency (IEA) reveal that the reduction of carbon dioxide emissions through renewable energy production is limited. Hence, a need arises for an alternate strategy to reduce carbon dioxide emissions immediately. It is claimed that carbon capture storage and utilization (CCSU) is a technology with the potential for significant reductions in carbon dioxide emissions within the next ten to twenty years.
The Quest for Alternate Strategies to Reduce Carbon Dioxide Emissions
This article focuses on the concept of carbon capture storage and utilization and explores current technologies used in the industries as well as new emerging technologies in India. In the oil and gas sector, carbon capture is carried out by processes such as post-combustion, pre-combustion, oxy-fuel combustion, and by direct-air capture method (National Energy Technology Laboratory). A solvent, sorbent, or membrane technology is used in the carbon capture methods. The captured carbon storage and utilization methods include geological storage, depleted gas and oil reservoirs, saline aquifers, un-mineable coal beds, deep oceans, and enhanced oil recovery (EOR) (National Energy Technology Laboratory).
Carbon capture storage and utilization (CCSU) is a method to capture carbon dioxide emissions from industrial flue gas streams. The carbon dioxide emissions majorly occur from coal-fired electricity generation power plants, oil and gas plants, and industrial processes. The carbon dioxide is captured either chemically, physically, or biologically and it is either stored or converted into useful chemicals. Captured carbon dioxide is stored in geological formations such as depleted oil and gas reservoirs, un-mineable coal seams, deep saline reservoirs, deep oceans, and enhanced oil recovery for over millions of years (ENERGY.GOV).
Carbon Capture Storage Methods
In the conventional oil wells, the oil from the oil wells is brought to the surface via the pressure of the pumps or by the natural pressure of the reservoir, resulting in 25% oil recovery from the oil wells. The Enhanced Oil Recovery method increases the recovery of oil (15%) by injecting substances into underground oil wells. This increases the pressure and reduces the oil viscosity. There are various EOR methods.
- The application of heat such as steam injection in thermal recovery lowers the oil’s viscosity and enhances the oils flow through the reservoir.
- Various gases such as nitrogen, natural gas, and carbon dioxide are injected into the oil wells and it expands in the reservoirs lowering the oil’s viscosity and pushing the additional oil to the surface. The captured carbon is sequestered in underground oil fields via pipelines to squeeze out the remaining oil in the older fields. The Enhanced Oil Recovery technology not only increases oil supplies and reduces our dependence on oil imports but also provides a safe and permanent method to store carbon dioxide underground.
Other carbon capture methods include Solid sorbents such as polymeric materials, activated carbonaceous materials, zeolites, metal-organic frameworks (MOFs), silica, alkali metal carbonates, and membrane technology
New Carbon Storage and Utilization Methods
Another option is to convert the captured carbon dioxide into useful chemicals in order to avoid high transportation and sequestration cost. This can be carried out at the site where carbon dioxide is being emitted. This method to permanently store carbon dioxide emissions from industrial and power plant sources provides good environmental benefits. Recently, industries and research institutes are showing interest in incorporating alternate carbon capture methods that are non-toxic, non-corrosive, and sustainable such as algae technology, non-aqueous solvent technology, alternate solvents to monoethanolamine (MEA), and diglycolamine (DGA) such as sodium carbonates. Other upcoming technologies in research and development include converting captured carbon into hydrogen, formic acid, and methane. Methane can not only be used as a fuel for transportation but can also serve as stored energy, which can be used later. Hence, methane as a fuel provides an alternative to depleting non-renewable sources of energy like petroleum and coal.
Synthesizing succinic acid from captured carbon dioxide as a method to biologically sequester carbon dioxide emissions is another approach. Succinic acid is an essential C4 building block chemical. Succinic acid with high productivity is produced by an isolated strain of genus Citrobacter. The occurrence of multiple gases in the flue stream such as air pollutants and moisture affect the durability and efficiency of the catalysts used to reduce carbon emissions to useful products such as methanol. The conversion steps involve various complex reaction steps and mechanisms that make it difficult to carry out a selective conversion of carbon dioxide to the desired product. In addition to this challenge, carbon dioxide reduction requires hydrogen. However, a substantial amount of hydrogen generation is difficult to achieve. Research work proposes bimetallic core-shell materials that include Ni, Cu, and Fe catalysts. The catalyst is also abundantly available and low in cost.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2021 Nikita Nandakumar Thattamprambil