scholarly journals Numerical simulation and combustion analysis of coal and biomass co-combustion

2022 ◽  
Vol 355 ◽  
pp. 02013
Author(s):  
Jiahu Li ◽  
Zhi Wang ◽  
Chi Ma
Keyword(s):  
Wheat Straw ◽  
Combustion Process ◽  
Clean Energy ◽  
Nozzle Position ◽  
Component Field ◽  
Fluent Software ◽  
Reduction Effect ◽  
Biomass Particles ◽  
Gas Component

China began entering the 14th Five-Year Plan period in 2021. With the proposed carbon-neutral long-term goal, the strategic position of clean energy is becoming increasingly prominent. using biomass power generation is one of the main application ways. In order to study the mixed combustion process of coal and biomass, this paper takes 300MW lignite boiler as the research object and uses Fluent software to explore the influence of biomass types and the location of biomass nozzle on the mixed combustion, and obtains the corresponding temperature field, flue gas component field and the distribution of pollutant NO. The results showed that when the biomass particles were sprayed into a fixed position with a certain proportion, the NO emission of wheat, corn and cotton straw was reduced, and the effect of wheat straw was the most obvious. When a certain proportion of wheat straw and coal are co-fired, the higher the biomass nozzle position, the higher the peak temperature in the main combustion zone, and the better the emission reduction effect of NO.

Power Projects and Covid-19: A Practical Analysis of the Relevance of Force Majeure Clauses under the Standardised Power Purchase and Implementation Agreements of Uganda

2020 ◽  
Vol 1 (2) ◽  
pp. 189-193
Author(s):  
Aisha Naiga ◽  
Loyola Rwabose Karobwa
Keyword(s):  
Renewable Energy ◽  
Renewable Energy Sources ◽  
Clean Energy ◽  
The State ◽  
Energy Sources ◽  
Policy Goals ◽  
Force Majeure ◽  
Practical Analysis ◽  
Energy Justice

Over 90% of Uganda's power is generated from renewable sources. Standardised Implementation Agreements and Power Purchase Agreements create a long-term relationship between Generating Companies and the state-owned off-taker guaranteed by Government. The COVID-19 pandemic and measures to curb the spread of the virus have triggered the scrutiny and application of force majeure (FM) clauses in these agreements. This article reviews the FM clauses and considers their relevance. The authors submit that FM clauses are a useful commercial tool for achieving energy justice by ensuring the continuity of the project, despite the dire effects of the pandemic. Proposals are made for practical considerations for a post-COVID-19 future which provides the continued pursuit of policy goals of promoting renewable energy sources and increasing access to clean energy, thus accelerating just energy transitions.

Technology Focus: Wellbore Tubulars (July 2021)

2021 ◽  
Vol 73 (07) ◽  
pp. 50-50
Author(s):  
Robello Samuel
Keyword(s):  
Geothermal Energy ◽  
Elevated Temperatures ◽  
Clean Energy ◽  
Well Integrity ◽  
The Future ◽  
Geothermal Wells ◽  
Abandoned Wells ◽  
Thermal Simulations ◽  
Technology Focus

How we think about the future of the pipe industry must evolve. How must tubular design and manufacturing change as we transition to clean energy? Geothermal energy is an area that needs attention and, further, needs very specific attention on tubulars. Tubulars are an important component in the construction of geothermal wells, and we must align our requirements for geothermal energy. Some of the main challenges encountered in geothermal wells are corrosion and scaling. Moreover, temperature becomes a major consideration for tubulars, even more so with the temperature excursion during geothermal production. Perhaps the critical aspect in the design of the geothermal wells involves casing selection and design. Beyond manufacturing casing pipes to withstand these problems, considering the manufacturing of other components, such as connections, float collars, and float shoes, also is essential. Thermal expansion and thermal excursion of casings are well-integrity concerns; thus, casing design is important for long-term sustainability of geothermal wells. Apart from thermal simulations, guidelines and software are needed to undergird the designs to withstand not only temperature excursions but also thermomechanical and thermochemical loadings. Engineered nonmetallic casings also provide an alternative solution because they provide the desired strength and corrosion resistance in addition to meeting the goals of sustainability. Undoubtedly, the future of the tubular industry is going to be revitalized. The question now is how we can retrofit existing abandoned wells for this purpose. Recommended additional reading at OnePetro: www.onepetro.org. SPE 199570 - Special Considerations for Well-Tubular Design at Elevated Temperatures by Gang Tao, C-FER Technologies, et al.

scholarly journals Testing the Environmental Kuznets Curve Hypothesis for Turkey: The Role of Clean Energy Consumption and Ecological Footprint

2020 ◽  
Author(s):  
Suleyman Yurtkuran
Keyword(s):  
Economic Growth ◽  
Energy Consumption ◽  
Capita Income ◽  
Environmental Kuznets Curve ◽  
Ecological Footprint ◽  
Clean Energy ◽  
Kuznets Curve ◽  
Per Capita ◽  
Environmental Kuznets Curve Hypothesis

Abstract This study aims to investigate the dynamic relationship between income, clean energy consumption, exports, imports, urbanization and ecological footprint for Turkey from 1973 to 2015 using the environmental Kuznets curve hypothesis. The long-term coefficients derived from the ARDL approach demonstrate that import increase the ecological footprint, whereas urbanization and clean energy consumption do not have an impact on environmental pollution in the long-term. In addition, the 2001 dummy variable is negative and statistically significant. The crisis in 2001 slowed down the economic growth rate. This situation also caused reduction of environmental pollution. Moreover, the long run estimates indicate that the EKC hypothesis is valid in Turkey. However, the turning point of per capita income was calculated as $16,045 that outside of the analyzed period. As economic activities increase, human pressure on nature continues to increase. Consequently, the only factor that reduces the ecological footprint has been determined as exports. In contrast, economic growth and clean energy consumption cannot be used as a tool to reduce the ecological footprint. Turkey needs a higher level of per capita income than the threshold level to improve environmental quality.

scholarly journals Evaluation method of clean power grid development mode

2021 ◽  
Vol 236 ◽  
pp. 02002
Author(s):  
Bingqi Jiao ◽  
Zhicheng Xu ◽  
Kuan Zheng ◽  
Xiaoqing Yan ◽  
Junshu Feng
Keyword(s):  
Evaluation Method ◽  
Power Grid ◽  
Clean Energy ◽  
Power Grids ◽  
Analysis Method ◽  
Development Mode ◽  
Grid Construction ◽  
Development Evaluation ◽  
Relative Change

In response to the climate change, it has been becoming the consensus of most countries in the world to accelerate the development of a high proportion of clean energy. The power grid is the core to support the development of a high proportion of clean energy, and the key is to accelerate the construction of clean power grids. This paper focuses on the main characteristics of clean power grid construction, and proposes a set of clean power grid development evaluation indicators including 5 first-level indicators and 19 second-level indicators and an analysis method based on radar charts. Taking China Power Grid as an example, this paper analyzes in detail the characteristics of the medium and long-term development mode of clean power grids and the relative change trends of specific indicators, and discusses the key links and potential problems that need attention in the development of clean power grids.

Evaluation of Clinical, Laboratory and Ultrasonography Variables as Prognostic Indicators in Equine Colic Surgery

2021 ◽  
Author(s):  
Gurpal Singh ◽  
Vandana Sangwan ◽  
Arun Anand ◽  
Jasmeet Singh Khosa ◽  
Simrat Sagar Singh ◽  
...  
Keyword(s):  
Wheat Straw ◽  
Prognostic Indicators ◽  
Peritoneal Cytology ◽  
Polymorphonuclear Cells ◽  
Intestinal Histology ◽  
Term Outcome ◽  
Long Term Outcome ◽  
Post Surgery ◽  
Equine Colic

Background: Equine colic surgery is an expensive procedure and availability of reliable prognostic indicators aid in decision making process. This study aimed to evaluate clinical, hemato-biochemistry, ultrasonography, surgery and peritoneal cytology / intestinal histology as prognostic indicators (based on strangulating vs non-strangulating lesion) for equine colic surgery. Methods: Fifteen equines {13 females and 2 males; 5 Thoroughbred, 9 Marwari and one mule} operated for intestinal colic were investigated. The feeding history, pre and post-surgery clinical, hematological and biochemical findings were recorded. Pre and post-surgery ultrasonography, peritoneal cytology and intestinal histology were done. Three equine were euthanized intra-operatively and 12 were followed for short and long term outcome. Result: On surgery, three equine were diagnosed for strangulating (right dorsal displacement of large colon, large colon volvulus and small colon strangulation) and 12 for non-strangulating colic {impaction (3), fecalith (5), sand colic (2), foreign body (1) and small intestine ileus (1)}. Detection of polymorphonuclear cells alone or with lymphocytes on peritoneal fluid cytology was indicator of good prognosis. Feeding of wheat straw is major predisposing factor for non-strangulating colic in Marwari breed but had favorable surgical prognosis (7/9=77.78%). While Thoroughbreds, not on wheat straw, are susceptible to strangulating colic that require early referral for favorable surgical outcome. Prolonged capillary refill time, injected mucous membranes, absent borborygymi, high serum creatine kinase and glucose are poor prognostic indicators for colic surgery. Thoroughbred equine with severe pain, elevated levels of Hb, neutrophils, packed cell volume (PCV), serum glucose and low peritoneal total protein are indicators of strangulating lesion. The equine colic surgery bears a very good short term (10/12=83.33%) and excellent (10/10=100%) long term outcome. 

Nutritive value index of treated wheat straw with Pleurotus fungi fed to cow

2007 ◽  
Vol 2007 ◽  
pp. 197-197
Author(s):  
Hassan Fazaeli ◽  
Seyed Ahmad Mirhadi
Keyword(s):  
Wheat Straw ◽  
Nutritive Value ◽  
Animal Feed ◽  
White Rot Fungi ◽  
White Rot ◽  
Fungal Treatment ◽  
Voluntary Intake

Biological de-lignification of straw by white-rot fungi seems a promising way of improving its nutritive value. The bio-conversion of lignocellulosic materials is circumscribed to the group of white-rot fungi, of which some species of Pleurotus are capable of producing upgraded spent-straws as ruminant feed (Fazaeli et al., 2004). Treating of cereal straw with white-rot fungi as animal feed was studied by several workers (Gupta et al., 1993; Zadrazil, 1997). However, most of the trials were conducted at in vitro stage and used cell wall degradation and in vitro digestibility as an index to evaluate the biological treatments. This experiment was conducted to study the effect of fungal treatment on the voluntary intake, in vivo digestibility and nutritive value index of wheat straw obtained from short-term and long-term solid state fermentation (SSF).

scholarly journals Measurement and calculating of supersonic ejectors

2019 ◽  
Vol 213 ◽  
pp. 02097
Author(s):  
Lukas Vojta ◽  
Vaclav Dvorak
Keyword(s):  
Stagnation Pressure ◽  
The Other ◽  
Ansys Fluent ◽  
Supersonic Ejector ◽  
Air Inlet ◽  
Optimum Position ◽  
Constant Area ◽  
Mixing Chamber ◽  
Nozzle Position ◽  
Fluent Software

This paper deals with numerical and experimental investigation of the flow in an air to air supersonic ejector with constant area mixing chamber. The mixing chamber of previous ejector was completely repaired since a scratch from previous turning had been found. As a result, a new geometry of the mixing chamber was created. Several measurements were conducted with different nozzle position (NP): 1 mm, 2 mm and 3 mm. Furthermore, for a given NP, two different values of stagnation pressure of 200 kPa and 300 kPa at the primary air inlet were investigated in more detail. All numerical simulations were performed in the ANSYS Fluent software. It was found that the influence of the position of the nozzle influences the ejection factor only to a certain extent. For the other parameters of the ejector is also a need to find the optimum position of the nozzle. Repair of the mixing chamber has contributed to reduce the pressure difference at the wall of the mixing chamber.

Photochemical conversion of AgCl nanocubes to hybrid AgCl–Ag nanoparticles with high activity and long-term stability towards photocatalytic degradation of organic dyes

2012 ◽  
Vol 90 (10) ◽  
pp. 858-864 ◽  
Author(s):  
Jizhuang Wang ◽  
Changhua An ◽  
Meiyu Zhang ◽  
Chuan Qin ◽  
Xijuan Ming ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Environmental Remediation ◽  
Organic Dyes ◽  
Clean Energy ◽  
Active Species ◽  
Significant Loss ◽  
Term Stability ◽  
Long Term Stability ◽  
Photochemical Conversion

The performance of a photocatalytic reaction is mainly determined by the quality of the photocatalyst. For real applications, significantly enhancing the stability and activity of the photocatalysts still remains a challenge for materials scientists and chemists. In this paper, we have achieved a highly efficient plasmonic AgCl–Ag nanophotocatalyst via photochemical conversion of AgCl nanocubes. Compared with reported photocatalysts, the as-achieved nanophotocatalyst exhibits superior activity, long-term stability, and wide applicability in the decomposition of organic dye pollutants. For example, only 30 s is needed to bleach methyl orange molecules assisted by AgCl–Ag nanoparticles. Furthermore, the catalyst can be reused up to 50 times without significant loss of activity. A possible mechanism was discussed and the specified photocatalytic reactions verified that both O2•– and OH• radicals were the main active species in decomposing pollutants. The excellent performance of the present photocatalyst suggests promising applications in environmental remediation, clean energy creation, and solar cells.

Phenomenological Modeling of Combustion in Pre-Chamber and the Pilot Flame for Natural Gas Engines

2019 ◽  
Author(s):  
Long Liu ◽  
Xia Wen ◽  
Qian Xiong ◽  
Xiuzhen Ma
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Alternative Fuels ◽  
Gas Flow ◽  
Combustion Process ◽  
Clean Energy ◽  
Combustion Model ◽  
Flame Surface ◽  
Flow Process ◽  
Natural Gas Engines

Abstract With energy shortages and increasing environmental problems, natural gas, as a clean energy, has the advantages of cheap price and large reserves and has become one of the main alternative fuels for marine diesel engines. For large bore natural gas engines, pre-chamber spark plug ignition can be used to increase engine efficiency. The engine mainly relies on the flame ejected from the pre-chamber to ignite the mixture of natural gas and air in the main combustion chamber. The ignition flame in the main combustion chamber is the main factor affecting the combustion process. Although the pre-chamber natural gas engines have been extensively studied, the characteristics of combustion in the pre-chamber and the development of ignition flame in the main combustion chamber have not been fully understood. In this study, a two-zone phenomenological combustion model of pre-chamber spark-ignition natural gas engines is established based on the exchange of mass and energy of the gas flow process in the pre-chamber and the main combustion chamber. The basic characteristics of the developed model are: a spherical flame surface is used to describe the combustion state in the pre-chamber, and according to the turbulent jet theory, the influence of turbulence on the state of the pilot flame is considered based on the Reynolds number. According to the phenomenological model, the time when the flame starts to be injected from the pre-chamber to the main combustion chamber, and the parameters such as the length of the pilot flame are analyzed. The model was verified by experimental data, and the results showed that the calculated values were in good agreement with the experimental values. It provides an effective tool for mastering the law of flame development and supporting the optimization of combustion efficiency.

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