Research

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21 pages, 4080 KiB

Open AccessArticle

One-Dimensional Analysis of Double Annular Combustor for Reducing Harmful Emissions

by Gijeong Jeong and Kyubok Ahn

Energies 2021, 14(13), 3930; https://0-doi-org.brum.beds.ac.uk/10.3390/en14133930 - 30 Jun 2021

Cited by 1 | Viewed by 2672

The number of aircraft flights worldwide has increased steadily since the introduction of air transportation to the public. Accordingly, environmental issues caused by the exhaust gases of aircraft engines have emerged. In particular, international organizations have crafted emission regulations since gases exhausted during [...] Read more.

The number of aircraft flights worldwide has increased steadily since the introduction of air transportation to the public. Accordingly, environmental issues caused by the exhaust gases of aircraft engines have emerged. In particular, international organizations have crafted emission regulations since gases exhausted during takeoff and landing have been identified as the direct cause of air pollution near airports. Nitrogen oxides (NOx) produced at high combustion temperatures and carbon monoxide (CO) due to incomplete combustion affect the performance of the combustion chamber. Therefore, annular combustors comprising two annular zones have been developed to reduce the emissions of these two substances, which occur under different conditions. Parameters that should be considered when modifying a conventional single annular (SAC) to a double annular combustor (DAC) are discussed herein. In this paper, an optimization algorithm for obtaining the main design parameters of the DAC is presented to minimize NOx and CO emissions and an operation solution for reducing carbon monoxide emission is identified. A thermodynamic model of a high-bypass turbofan engine (PS-90A) is used to establish the inlet and outlet conditions of the combustor. Analysis results show that NOx emissions can be effectively reduced by adjusting the design parameters and CO emissions can be significantly decreased by partially turning off the fuel supply based on the engine cycle. Full article

(This article belongs to the Special Issue Technologies Conducive to Low Green House Gas Emission)

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22 pages, 9082 KiB

Open AccessArticle

Monofacial and Bifacial Micro PV Installation as Element of Energy Transition—The Case of Poland

by Piotr Olczak, Małgorzata Olek, Dominika Matuszewska, Artur Dyczko and Tomasz Mania

Energies 2021, 14(2), 499; https://0-doi-org.brum.beds.ac.uk/10.3390/en14020499 - 18 Jan 2021

Cited by 33 | Viewed by 3577

Abstract

The several government subsidies available in Poland contributed to an increased interest in PV installations. Installed PV capacity increased from 100 MW in 2016 up to 2682.7 MW in July 2020. In 2019 alone, 104,000 microinstallations (up to 50 kWp) were installed in [...] Read more.

The several government subsidies available in Poland contributed to an increased interest in PV installations. Installed PV capacity increased from 100 MW in 2016 up to 2682.7 MW in July 2020. In 2019 alone, 104,000 microinstallations (up to 50 kWp) were installed in Poland. The paper determines the energy gain and the associated reduction of CO₂ emissions for two types of solar installation located in Poland. The monofacial solar modules with a power of 5.04 kWp (located in Leki) and bifacial solar modules with a power of 6.1 kWp (located in Bydgoszcz). Both installations use mono-crystalline Si-based 1st generation PV cells. With comparable insolation, a bifacial installation produces approx. 10% (for high insolation) to 28% (for low insolation) more energy than a monofacial PV installation. Avoided annual CO₂ emission in relation to the installation capacity ranges from 0.58 to 0.64 Mg/kWp for monofacial and from 0.68 to 0.74 Mg/kWp for bifacial and is on average approx. 16% higher for bifacial installations. Cost-benefit analyses were made. For different electricity prices, the NPV for monofacial and bifacial was determined. Full article

(This article belongs to the Special Issue Technologies Conducive to Low Green House Gas Emission)

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18 pages, 6961 KiB

Open AccessArticle

Low Emissions Resulting from Combustion of Forest Biomass in a Small Scale Heating Device

by Karol Tucki, Olga Orynycz, Andrzej Wasiak, Antoni Świć, Leszek Mieszkalski and Joanna Wichłacz

Energies 2020, 13(20), 5495; https://0-doi-org.brum.beds.ac.uk/10.3390/en13205495 - 20 Oct 2020

Cited by 11 | Viewed by 2278

Abstract

The paper concerns the analysis of harmful emissions during the combustion process in households. The subject of the analysis is a low emission heating device with an output of 50 kW for burning biomass of forest origin (low-quality hardwoods or softwoods). The proposed [...] Read more.

The paper concerns the analysis of harmful emissions during the combustion process in households. The subject of the analysis is a low emission heating device with an output of 50 kW for burning biomass of forest origin (low-quality hardwoods or softwoods). The proposed boiler is automatically fed from the connected container by means of a screw conveyor. In this way, the optimum amount of fuel is supplied for maximum heat output (adjustment of the ratio of primary air to fuel). The proposed biomass heating system is equipped with a primary and secondary air supply system and exhaust gas sensors. This ensures optimal regulation of the air mixture and efficient and clean combustion. Proper control of the combustion process, control of the air supply by means of a lambda sensor and power control of the system ensure a low-emission combustion process. The system precisely adjusts to the heat demand. This results in highly efficient heating technology with low operating costs. In the presented work, the emission of exhaust gases from the proposed heating device during the combustion of woodchips and beech–oak pellets were measured. It is demonstrated that the proposed design of the boiler equipped with intelligent control significantly reduces emissions when the biomass solid fuels are used, e.g., CO emissions from beech and oak chips and pellets in the low-emission boiler—18 extract pipes shows the value <100 ppm, which is even lower than when gas is burned in the other boilers; on the other hand, the pine chips show even higher emission when burned in the low-emission burner. Consequently, the choice of biomass source and form of the fuel play some role in the emissions observed. Full article

(This article belongs to the Special Issue Technologies Conducive to Low Green House Gas Emission)

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16 pages, 14453 KiB

Open AccessArticle

Parametric Study of Various Thermodynamic Cycles for the Use of Unconventional Blends

by Odi Fawwaz Alrebei, Philip Bowen and Agustin Valera Medina

Energies 2020, 13(18), 4656; https://0-doi-org.brum.beds.ac.uk/10.3390/en13184656 - 07 Sep 2020

Cited by 6 | Viewed by 1802

Abstract

This paper aims to conduct a parametric study for five gas turbine cycles (namely, simple, heat exchanged, free turbine and simple cycle, evaporative, and humidified) using a CO₂-argon-steam-oxyfuel (CARSOXY) mixture as a working fluid to identify their optimal working conditions with [...] Read more.

This paper aims to conduct a parametric study for five gas turbine cycles (namely, simple, heat exchanged, free turbine and simple cycle, evaporative, and humidified) using a CO₂-argon-steam-oxyfuel (CARSOXY) mixture as a working fluid to identify their optimal working conditions with respect to cycle efficiency and specific work output. The performance of the five cycles using CARSOXY is estimated for wet and dry compression, and a cycle is suggested for each range of working conditions. The results of this paper are based on MATLAB codes, which have been developed to conduct the cycle analysis for CARSOXY gas turbines, assuming a stoichiometric condition with an equivalence ratio of 1.0. Analyses are based on the higher heating value (HHV) of methane as fuel. This paper also identifies domains of operating conditions for each cycle, where the efficiency of CARSOXY cycles can be increased by up to 12% compared to air-driven cycles. The CARSOXY heat exchanged cycle has the highest efficiency among the other CARSOXY cycles in the compressor pressure ratio domain of 2–3 and 6–10, whereas, at 3–6, the humidified cycle has the highest efficiency. The evaporative cycle has intermediate efficiency values, while the simple cycle and the free turbine-simple cycle have the lowest efficiencies amongst the five cycles. Additionally, a 10% increase in the cycle efficiency can be theoretically achieved by using the newly suggested CARSOXY blend that has the molar fractions of 47% argon, 10% carbon dioxide, 10% H₂O, and 33% oxyfuel at low compressor inlet temperatures, thus theoretically enabling the use of carbon capture technologies. Full article

(This article belongs to the Special Issue Technologies Conducive to Low Green House Gas Emission)

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18 pages, 11275 KiB

Open AccessArticle

The Combustion of Methane from Hard Coal Seams in Gas Engines as a Technology Leading to Reducing Greenhouse Gas Emissions—Electricity Prediction Using ANN

by Marek Borowski, Piotr Życzkowski, Jianwei Cheng, Rafał Łuczak and Klaudia Zwolińska

Energies 2020, 13(17), 4429; https://0-doi-org.brum.beds.ac.uk/10.3390/en13174429 - 27 Aug 2020

Cited by 10 | Viewed by 2589

Abstract

Greenhouse gases such as carbon dioxide and methane cause global warming and consequently climate change. Great efforts are being made to reduce greenhouse gas emissions with the objective of addressing this problem, hence the popularity of technologies conductive to reducing greenhouse gas emissions. [...] Read more.

Greenhouse gases such as carbon dioxide and methane cause global warming and consequently climate change. Great efforts are being made to reduce greenhouse gas emissions with the objective of addressing this problem, hence the popularity of technologies conductive to reducing greenhouse gas emissions. CO₂ emissions can be reduced by improving the thermal efficiency of combustion engines, for example, by using cogeneration systems. Coal mine methane (CMM) emerges due to mining activities as methane released from the coal and surrounding rock strata. The amount of methane produced is primarily influenced by the productivity of the coal mine and the gassiness of the coal seam. The gassiness of the formation around the coal seam and geological conditions are also important. Methane can be extracted to the surface using methane drainage installations and along with ventilation air. The large amounts of methane captured by methane drainage installations can be used for energy production. This article presents a quarterly summary of the hourly values of methane capture, its concentration in the methane–air mixture, and electricity production in the cogeneration system for electricity and heat production. On this basis, neural network models have been proposed in order to predict electricity production based on known values of methane capture, its concentration, pressure, and parameters determining the time and day of the week. A prediction model has been established on the basis of a multilayer perceptron network (MLP). Full article

(This article belongs to the Special Issue Technologies Conducive to Low Green House Gas Emission)

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16 pages, 4011 KiB

Open AccessArticle

Prototypical Biomass-Fired Micro-Cogeneration Systems—Energy and Ecological Analysis

by Krzysztof Sornek

Energies 2020, 13(15), 3909; https://0-doi-org.brum.beds.ac.uk/10.3390/en13153909 - 31 Jul 2020

Cited by 12 | Viewed by 2287

Abstract

Combined heat and power systems dedicated to micro-scale applications are currently increasing in popularity. The use of such systems is beneficial from the standpoint of increasing the usage of renewable energy, increasing energy efficiency and reducing CO₂ emissions into the atmosphere. This [...] Read more.

Combined heat and power systems dedicated to micro-scale applications are currently increasing in popularity. The use of such systems is beneficial from the standpoint of increasing the usage of renewable energy, increasing energy efficiency and reducing CO₂ emissions into the atmosphere. This paper shows two examples of prototypical micro-cogeneration systems powered by biomass. In the first, smaller one, electricity is generated in thermoelectric generators using heat from the wood-fired stove. The second one is equipped with a 100 kW_t batch boiler and operates according to a modified Rankine cycle. The energy and ecological analysis were conducted and discussed, including selected aspects of heat and power generation and gaseous pollutant emission. Measurements were performed using a dedicated control and measurement station with a PLC controller. As was shown, thermoelectric generators operated respectively with the power of 22.5 W_e in the case of the air-cooled unit and 31.2 W_e in the case of the water-cooled unit. On the other hand, the maximum power level of ca. 1145 W_e was obtained in the system with a batch boiler operating according to a modified Rankine cycle. The ecological analysis showed that the average amount of CO emission during the wood combustion in the tested stove was 1916 mg/m³ (in the combustion phase). In the case of straw combustion, it was characterized by lower CO₂ emissions compared to coal, but higher CO₂ emissions compared to gasoline and natural gas. Based on the obtained results, some outlines for the systems development were given. Full article

(This article belongs to the Special Issue Technologies Conducive to Low Green House Gas Emission)

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14 pages, 5450 KiB

Open AccessArticle

Simulation Model of Regenerative LNG Refrigeration System for Re-Liquification of BOG

by Sung-Hun Son and Kibum Kim

Energies 2020, 13(15), 3894; https://0-doi-org.brum.beds.ac.uk/10.3390/en13153894 - 30 Jul 2020

Cited by 4 | Viewed by 1941

Abstract

Boil-off gas (BOG) disposal in liquefied natural gas (LNG) tankers has long been considered inevitable owing to the constant vaporization of the LNG in the storage tanks, but results in energy waste and environmental pollution. To address these challenges, we developed a re-liquification [...] Read more.

Boil-off gas (BOG) disposal in liquefied natural gas (LNG) tankers has long been considered inevitable owing to the constant vaporization of the LNG in the storage tanks, but results in energy waste and environmental pollution. To address these challenges, we developed a re-liquification system that can condense the BOG and return it to the storage tank. The re-liquification system was modeled, and a case study was conducted to evaluate the viability of the system. The energy waste, which was quantified by tonnes of oil equivalent (TOE), greenhouse-gas emissions in tonnes of carbon dioxide (TCO₂), and cost reduction in millions of U.S. dollars (MUSD), was evaluated for five different tanker cruising speeds. The re-liquification system significantly reduced the average TOE, TCO₂, and cost by up to 9120.40 TOE/year, 19,474.33 TCO₂/year, and 1.9765 MUSD/year, respectively, for five different tanker speeds with multi-stage compression. Full article

(This article belongs to the Special Issue Technologies Conducive to Low Green House Gas Emission)

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Review

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25 pages, 2731 KiB

Open AccessReview

Utilization of Gaseous Carbon Dioxide and Industrial Ca-Rich Waste for Calcium Carbonate Precipitation: A Review

by Natalia Czaplicka and Donata Konopacka-Łyskawa

Energies 2020, 13(23), 6239; https://0-doi-org.brum.beds.ac.uk/10.3390/en13236239 - 26 Nov 2020

Cited by 19 | Viewed by 4274

Abstract

Technologies for the management of various types of waste and the production of useful products from them are currently widely studied. Both carbon dioxide and calcium-rich waste from various production processes are problematic wastes that can be used to produce calcium carbonate. Therefore, [...] Read more.

Technologies for the management of various types of waste and the production of useful products from them are currently widely studied. Both carbon dioxide and calcium-rich waste from various production processes are problematic wastes that can be used to produce calcium carbonate. Therefore, the purpose of this paper is to provide an overview about the state of the development of processes that use these two wastes to obtain a valuable CaCO₃ powder. The paper reviews the current research on the use of post-distillation liquid from the Solvay process, steelmaking slag, concrete, cement, and gypsum waste as well as some others industrial Ca-rich waste streams in the calcium carbonate precipitation process via carbonation route. This work is an attempt to collect the available information on the possibility of influencing the characteristics of the obtained calcium carbonate. It also indicates the possible limitations and implementation problems of the proposed technologies. Full article

(This article belongs to the Special Issue Technologies Conducive to Low Green House Gas Emission)

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