Related Research Articles
A heat engine is a system that converts heat to usable energy, particularly mechanical energy, which can then be used to do mechanical work. While originally conceived in the context of mechanical energy, the concept of the heat engine has been applied to various other kinds of energy, particularly electrical, since at least the late 19th century. The heat engine does this by bringing a working substance from a higher state temperature to a lower state temperature. A heat source generates thermal energy that brings the working substance to the higher temperature state. The working substance generates work in the working body of the engine while transferring heat to the colder sink until it reaches a lower temperature state. During this process some of the thermal energy is converted into work by exploiting the properties of the working substance. The working substance can be any system with a non-zero heat capacity, but it usually is a gas or liquid. During this process, some heat is normally lost to the surroundings and is not converted to work. Also, some energy is unusable because of friction and drag.
Gasification is a process that converts biomass- or fossil fuel-based carbonaceous materials into gases, including as the largest fractions: nitrogen (N2), carbon monoxide (CO), hydrogen (H2), and carbon dioxide (CO2). This is achieved by reacting the feedstock material at high temperatures (typically >700 °C), without combustion, via controlling the amount of oxygen and/or steam present in the reaction. The resulting gas mixture is called syngas (from synthesis gas) or producer gas and is itself a fuel due to the flammability of the H2 and CO of which the gas is largely composed. Power can be derived from the subsequent combustion of the resultant gas, and is considered to be a source of renewable energy if the gasified compounds were obtained from biomass feedstock.
Fluidized bed combustion (FBC) is a combustion technology used to burn solid fuels.
The Brayton cycle, also known as the Joule cycle, is a thermodynamic cycle that describes the operation of certain heat engines that have air or some other gas as their working fluid. It is characterized by isentropic compression and expansion, and isobaric heat addition and rejection, though practical engines have adiabatic rather than isentropic steps.
A combined cycle power plant is an assembly of heat engines that work in tandem from the same source of heat, converting it into mechanical energy. On land, when used to make electricity the most common type is called a combined cycle gas turbine (CCGT) plant, which is a kind of gas-fired power plant. The same principle is also used for marine propulsion, where it is called a combined gas and steam (COGAS) plant. Combining two or more thermodynamic cycles improves overall efficiency, which reduces fuel costs.
The Rankine cycle is an idealized thermodynamic cycle describing the process by which certain heat engines, such as steam turbines or reciprocating steam engines, allow mechanical work to be extracted from a fluid as it moves between a heat source and heat sink. The Rankine cycle is named after William John Macquorn Rankine, a Scottish polymath professor at Glasgow University.
A supercritical fluid (SCF) is any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist, but below the pressure required to compress it into a solid. It can effuse through porous solids like a gas, overcoming the mass transfer limitations that slow liquid transport through such materials. SCFs are superior to gases in their ability to dissolve materials like liquids or solids. Also, near the critical point, small changes in pressure or temperature result in large changes in density, allowing many properties of a supercritical fluid to be "fine-tuned".
A combustor is a component or area of a gas turbine, ramjet, or scramjet engine where combustion takes place. It is also known as a burner, burner can, combustion chamber or flame holder. In a gas turbine engine, the combustor or combustion chamber is fed high-pressure air by the compression system. The combustor then heats this air at constant pressure as the fuel/air mix burns. As it burns the fuel/air mix heats and rapidly expands. The burned mix is exhausted from the combustor through the nozzle guide vanes to the turbine. In the case of a ramjet or scramjet engines, the exhaust is directly fed out through the nozzle.
Supercritical carbon dioxide is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure.
The steam-electric power station is a power station in which the electric generator is steam driven. Water is heated, turns into steam and spins a steam turbine which drives an electrical generator. After it passes through the turbine, the steam is condensed in a condenser. The greatest variation in the design of steam-electric power plants is due to the different fuel sources.
An integrated gasification combined cycle (IGCC) is a technology using a high pressure gasifier to turn coal and other carbon based fuels into pressurized gas—synthesis gas (syngas). It can then remove impurities from the syngas prior to the electricity generation cycle. Some of these pollutants, such as sulfur, can be turned into re-usable byproducts through the Claus process. This results in lower emissions of sulfur dioxide, particulates, mercury, and in some cases carbon dioxide. With additional process equipment, a water-gas shift reaction can increase gasification efficiency and reduce carbon monoxide emissions by converting it to carbon dioxide. The resulting carbon dioxide from the shift reaction can be separated, compressed, and stored through sequestration. Excess heat from the primary combustion and syngas fired generation is then passed to a steam cycle, similar to a combined cycle gas turbine. This process results in improved thermodynamic efficiency, compared to conventional pulverized coal combustion.
Supercritical fluid chromatography (SFC) is a form of normal phase chromatography that uses a supercritical fluid such as carbon dioxide as the mobile phase. It is used for the analysis and purification of low to moderate molecular weight, thermally labile molecules and can also be used for the separation of chiral compounds. Principles are similar to those of high performance liquid chromatography (HPLC); however, SFC typically utilizes carbon dioxide as the mobile phase. Therefore, the entire chromatographic flow path must be pressurized. Because the supercritical phase represents a state whereby bulk liquid and gas properties converge, supercritical fluid chromatography is sometimes called convergence chromatography. The idea of liquid and gas properties convergence was first envisioned by Giddings.
Oxy-fuel combustion is the process of burning a fuel using pure oxygen, or a mixture of oxygen and recirculated flue gas, instead of air. Since the nitrogen component of air is not heated, fuel consumption is reduced, and higher flame temperatures are possible. Historically, the primary use of oxy-fuel combustion has been in welding and cutting of metals, especially steel, since oxy-fuel allows for higher flame temperatures than can be achieved with an air-fuel flame. It has also received a lot of attention in recent decades as a potential carbon capture and storage technology.
A transcritical cycle is a closed thermodynamic cycle where the working fluid goes through both subcritical and supercritical states. In particular, for power cycles the working fluid is kept in the liquid region during the compression phase and in vapour and/or supercritical conditions during the expansion phase. The ultrasupercritical steam Rankine cycle represents a widespread transcritical cycle in the electricity generation field from fossil fuels, where water is used as working fluid. Other typical applications of transcritical cycles to the purpose of power generation are represented by organic Rankine cycles, which are especially suitable to exploit low temperature heat sources, such as geothermal energy, heat recovery applications or waste to energy plants. With respect to subcritical cycles, the transcritical cycle exploits by definition higher pressure ratios, a feature that ultimately yields higher efficiencies for the majority of the working fluids. Considering then also supercritical cycles as a valid alternative to the transcritical ones, the latter cycles are capable of achieving higher specific works due to the limited relative importance of the work of compression work. This evidences the extreme potential of transcritical cycles to the purpose of producing the most power with the least expenditure.
A closed-cycle gas turbine is a turbine that uses a gas for the working fluid as part of a closed thermodynamic system. Heat is supplied from an external source. Such recirculating turbines follow the Brayton cycle.
The circulating fluidized bed (CFB) is a type of fluidized bed combustion that utilizes a recirculating loop for even greater efficiency of combustion. while achieving lower emission of pollutants. Reports suggest that up to 95% of pollutants can be absorbed before being emitted into the atmosphere. The technology is limited in scale however, due to its extensive use of limestone, and the fact that it produces waste byproducts.
An internal combustion engine is a heat engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons, turbine blades, a rotor, or a nozzle. This force moves the component over a distance. This process transforms chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to.
Lower-temperature fuel cell types such as the proton exchange membrane fuel cell, phosphoric acid fuel cell, and alkaline fuel cell require pure hydrogen as fuel, typically produced from external reforming of natural gas. However, fuels cells operating at high temperature such as the solid oxide fuel cell (SOFC) are not poisoned by carbon monoxide and carbon dioxide, and in fact can accept hydrogen, carbon monoxide, carbon dioxide, steam, and methane mixtures as fuel directly, because of their internal shift and reforming capabilities. This opens up the possibility of efficient fuel cell-based power cycles consuming solid fuels such as coal and biomass, the gasification of which results in syngas containing mostly hydrogen, carbon monoxide and methane which can be cleaned and fed directly to the SOFCs without the added cost and complexity of methane reforming, water gas shifting and hydrogen separation operations which would otherwise be needed to isolate pure hydrogen as fuel. A power cycle based on gasification of solid fuel and SOFCs is called an Integrated Gasification Fuel Cell (IGFC) cycle; the IGFC power plant is analogous to an integrated gasification combined cycle power plant, but with the gas turbine power generation unit replaced with a fuel cell power generation unit. By taking advantage of intrinsically high energy efficiency of SOFCs and process integration, exceptionally high power plant efficiencies are possible. Furthermore, SOFCs in the IGFC cycle can be operated so as to isolate a carbon dioxide-rich anodic exhaust stream, allowing efficient carbon capture to address greenhouse gas emissions concerns of coal-based power generation.
The Whitetail Clean Energy is a proposed power station in Wilton, Redcar and Cleveland, England. The generating process of the plant is listed as a "clean energy source", using natural gas and oxygen in a Allam-Fetvedt Cycle to create power. The excess carbon dioxide not used by the co-generation process is intended to be captured and stored under the North Sea, making the plant the first in the United Kingdom to utilise this type of technology, and also using carbon sequestration under the North Sea. The plant is also included in the Net Zero Teesside project. The power plant is proposed to start generating in 2025.
Supercritical carbon dioxide blend (sCO2 blend) is an homogeneous mixture of CO2 with one or more fluids (dopant fluid) where it is held at or above its critical temperature and critical pressure.
References
- ↑ Carbonaceous fuels include natural gas, biomass, coal, municipal solid waste, and sour gas (natural gas with a high content of sulfur dioxide).
- 1 2 USpatent 8959887,Allam; Rodney John (Wiltshire, GB), Brown, Jr.; Glenn William (Durham, NC), Palmer; Miles R. (Chapel Hill, NC),; Brown, Jr., Glenn William& Palmer, Miles R.,"System and method for high efficiency power generation using a carbon dioxide circulating working fluid",published 2015-02-24,issued 2013-11-04, assigned to Palmer Labs, LLCand 8 Rivers Capital, LLC
- 1 2 USpatent 8986002,Palmer; Miles R. (Chapel Hill, NC), Allam; Rodney John (Chippenham, GB), Brown, Jr.; Glenn William (Durham, NC), Fetvedt; Jeremy Eron (Raleigh, NC); Allam, Rodney John& Brown, Jr., Glenn Williamet al.,"Apparatus for combusting a fuel at high pressure and high temperature, and associated system",published 2015-03-24, assigned to 8 Rivers Capital, LLCand Palmer Labs, LLC
- 1 2 USpatent 9062608,Allam; Rodney John (Wiltshire, GB), Palmer; Miles R. (Chapel Hill, NC), Brown, Jr.; Glenn William (Durham, NC); Palmer, Miles R.& Brown, Jr., Glenn William,"System and method for high efficiency power generation using a carbon dioxide circulating working fluid",published 2015-06-23,issued 2013-03-13, assigned to Palmer Labs, LLCand 8 Rivers Capital, LLC
- 1 2 USpatent 9068743,Palmer; Miles R. (Great Falls, VA), Allam; Rodney John (Chippenham, GB), Brown, Jr.; Glenn William (Durham, NC); Allam, Rodney John& Brown, Jr., Glenn William,"Apparatus for combusting a fuel at high pressure and high temperature, and associated system",issued 2015-03-24, assigned to 8 Rivers Capital, LLCand Palmer Labs, LLC
- 1 2 USpatent 9416728,Palmer; Miles R. (Great Falls, VA), Allam; Rodney John (Chippenham, GB), Brown, Jr.; Glenn William (Durham, NC); Allam, Rodney John& Brown, Jr., Glenn William,"Apparatus and method for combusting a fuel at high pressure and high temperature, and associated system and device",issued 2016-08-16, assigned to 8 Rivers Capital, LLCand Palmer Labs, LLC
- 1 2 USpatent 9869245,Allam; Rodney John (Wiltshire, GB), Palmer; Miles R. (Chapel Hill, NC), Brown, Jr.; Glenn William (Durham, NC); Palmer, Miles R.& Brown, Jr., Glenn William,"System and method for high efficiency power generation using a carbon dioxide circulating working fluid",published 2015-09-10,issued 2018-01-16, assigned to 8 Rivers Capital, LLC
- 1 2 USpatent 10018115,Palmer; Miles R. (Chapel Hill, NC), Allam; Rodney John (Chippenham, GB), Brown, Jr.; Glenn William (Durham, NC), Fetvedt; Jeremy Eron (Raleigh, NC); Allam, Rodney John& Brown, Jr., Glenn Williamet al.,"System and method for high efficiency power generation using a carbon dioxide circulating working fluid",published 2015-03-24, assigned to 8 Rivers Capital, LLC
- 1 2 USpatent 10047671,Allam; Rodney John (Wiltshire, GB), Brown, Jr.; Glenn William (Durham, NC), Palmer; Miles R. (Chapel Hill, NC),; Brown, Jr., Glenn William& Palmer, Miles R.,"System and method for high efficiency power generation using a carbon dioxide circulating working fluid",published 2018-08-14,issued 2015-01-23, assigned to Palmer Labs, LLCand 8 Rivers Capital, LLC
- ↑ "2018". MIT Technology Review. Retrieved 2020-10-01.
- ↑ "Breaking ground for a groundbreaker: the first Allam Cycle power plant". Modern Power Systems. 15 May 2016. Retrieved 29 November 2016.
- ↑ Isles, Junior (2014). "Gearing up for a new supercritical CO2 power cycle system" (PDF). Gas Turbine World. Vol. 44, no. 6. Pequot Publishing. Archived from the original (PDF) on 11 August 2016. Retrieved 29 November 2016.
- ↑ Grant, Annalee (6 March 2015). "Exelon, NET Power confident in planned carbon capture pilot project in Texas". SNL. S&P Global. Retrieved 29 November 2016.
- ↑ Dodge, Edward (14 November 2014). "CCS Breakthrough: sCO2 Power Cycles Offer Improved Efficiency and Integrated Carbon Capture". Breaking Energy. Breaking Media. Retrieved 29 November 2016.
- ↑ Allam, Rodney; Martin, Scott; Forrest, Brock; Fetvedt, Jeremy; Lu, Xijia; Freed, David; Brown, G. William; Sasaki, Takashi; Itoh, Masao; Manning, James (2017-07-01). "Demonstration of the Allam Cycle: An Update on the Development Status of a High Efficiency Supercritical Carbon Dioxide Power Process Employing Full Carbon Capture". Energy Procedia. 114: 5948–5966. doi: 10.1016/j.egypro.2017.03.1731 . ISSN 1876-6102.
- ↑ Lu, Xijia; Forrest, Brock; Martin, Scott; Fetvedt, Jeremy; McGroddy, Michael; Freed, David (2016-09-20). "Integration and Optimization of Coal Gasification Systems With a Near-Zero Emissions Supercritical Carbon Dioxide Power Cycle". Proceedings of the ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy. American Society of Mechanical Engineers Digital Collection. doi:10.1115/GT2016-58066. ISBN 978-0-7918-4987-3.
- ↑ Rathi, Akshat (31 May 2018). "A US startup has lit the first fire in its zero-emissions fossil-fuel power plant". Quartz. Retrieved 2020-10-01.
- ↑ "Power Engineering International". Power Engineering International. 18 November 2021. Retrieved November 18, 2021.
- ↑ LLC, NET Power. "NET Power Demonstration Plant Wins 2018 ADIPEC Breakthrough Technological Project of the Year". www.prnewswire.com (Press release). Retrieved 2020-10-01.