Justification of the Energy Use of Cedar Husk Waste as an Environmentally Friendly Additive for Co-Combustion with Coal

In this paper, the properties of ignition of mixed fuel pellets formed on the basis of fairly typical energy coal and wood industry waste in the form of cedar husks are experimentally established. The technical characteristics of the initial fuel components and the mixtures based on them, the ignition delay times for different mass concentrations of biomass in coal, and the composition of flue gases formed during the thermal decomposition of these mixed fuels and their base components were determined. Pellets of mixed fuels were made by a hydraulic press. The experiments were performed in an air environment at temperatures from 600 °C to 800 °C. Recording of the processes of pellet ignition and combustion was carried out using a high-speed video camera with an image format of 1024 × 1024 pixels, and a frame rate up to 500 frames per second. The analysis of the flue gas composition was performed using a Test-1 factory gas analyzer (BONER Co.). It was found that the increase in the share of biomass up to 50% in the mixed fuel led to a significant reduction in the ignition delay time to less than 1 s and the sequestration of sulfur oxide emissions by 37.6% and of nitrogen oxides by 3.8% in the studied granular mixed fuels.

Neutronic Performance of a Compact 10 MWe Nuclear Reactor with Low Enrichment (ThxU1−x)N Fuel

Recent interest in compact nuclear reactors for applications in space or in remote locations drives innovation in nuclear fuel design, especially non-oxide ceramic nuclear fuels. This work details neutronic modeling designed to support the development of a new nuclear fuel concept based on a mixture of thorium and uranium nitride. A Monte Carlo N-Particle Version 6.2 (MCNP-6) model of a compact 10 MWe reactor design which incorporates (ThxU1−x)N fuel is presented. In this context, a “compact” reactor is a completely assembled reactor which may be emptied of coolant and transported by specialized commercial vehicle, deployed by a C130J aircraft, or launched into space. Core geometry, reflector barrels, and the heat exchange zones are designed to support reduction of overall reactor volume of core components while maintaining criticality with a fixed total fuel mass of 4500 kg. Dense mixed nitrides of thorium nitride (ThN) additions in uranium nitride (UN) in 5 wt.% increments between $$0.05 \le x \le 0.5$$ 0.05 ≤ x ≤ 0.5 have been considered for calculation of $$k_{\infty }$$ k ∞ and $$k_{{{\text{effective}}}}$$ k effective . ThN additions in UN results in a slight increase in the magnitude of the temperature coefficient of reactivity, which is negative by design. The isotopic distribution of the principal actinide inventory as a function of burnup, time, and initial fuel composition is presented and discussed within the context of the proliferation risk of this core design.

Analysis of conversion of water transport engines to liquefied natural gas

The article considers the problems of preservation and the most economical use of existing energy sources with minimal emissions into the environment, which are urgent in modern conditions. Tightening measures to exclude or minimize the negative impact on the nature is an objective vital necessity for the survival of humanity on the planet. The search for the most environmentally friendly fuel is an important task for researchers in various fields of modern science. The measures of the International Maritime Organization (IMO) on tightening the environmental requirements at sea and the advantages of the conversion of transportation means, including ships, from black oil to liquefied natural gas are outlined. It has been stated that since 01.01.2020 IMO has put forward the requirements for the sulfur concentration in the initial fuel up to 0.5%. The sulfur content in marine fuels is illustrated, according to the current standards. Possible advantages for the Russian Federation are considered in the event that appropriate legislative acts are adopted in the field of shipbuilding and the operation of ships. The advantages of liquefied natural gas compared to other fuels are listed. The forecast values of the demand for liquefied natural gas for bunkering ships for 2020–2040 are illustrated. Research has been carried out and a formula has been derived to determine the conditions for the transition of ships to liquefied natural gas. Existing and possible in the near future projects for the generation of liquefied natural gas in the Arctic zone of Russia are considered. It is concluded that the Russian Federation has vast deposits of natural gas and scientific and technical potential for the development and revival of shipbuilding both within the country and abroad.

Analysis of the vaporization processes in the vehicle fuel tank. New equation for determining the vapor amount

Introduction (problem statement and relevance). Hydrocarbon emissions from vaporizationtank fuel contribute significantly to the total emissions of hazardous substances from vehicles equipped with spark ignition engines. To meet the established standards for limiting hydrocarbon emissions caused by evaporation, all modern vehicles use fuel vapor recovery systems, the optimal parameters of which require the availability and application of mathematical models and methods for their determination.The purpose of the research was to develop a model of vapor generation processes in the car fuel tank and a methodology for determining the main quantitative parameters of the vapor-air mixture.Methodology and research methods. The analysis of the processes of vapor generation in the fuel tank was carried out. It was shown that the mass of hydrocarbons generated in the steam space was directly proportional to its volume and did not depend on the amount of fuel in the tank.Scientific novelty and results. New analytical dependences of the vaporization amount on the saturated vapor pressure, barometric pressure, initial fuel temperature and fuel heating during parking have been obtained.Practical significance. A formula was obtained to estimate the temperature of gasoline boiling starting in the tank, depending on the altitude above sea level and the volatility of gasoline, determined by the pressure of saturated vapors. Using the new equations, the vaporization analysis in real situations (parking, idling, refueling, explosive concentration of vapors) was carried out.

Plant community response to fuel break and goat grazing in southern California

Background: California is a global biodiversity hotspot, yet increased urbanization of wildlands, warming temperatures, and invasion of nonnative species pose serious risks to these areas due to an increase in wildfire frequency. Fuel management is a tool for reducing fire risk to neighboring communities and natural resources that involves a two-step process requiring an initial reduction of woody vegetation followed by a repeated control of woody plants and reduction of herbaceous cover. To understand the compositional and structural changes resulting from fuel treatment methods in southern California chaparral, we evaluated the compositional and structural impacts of a recently created fuel break established around the Lake Morena community on the Cleveland National Forest. The area was initially treated with cut and pile burning, then treated with herbicide, and lastly grazed by 1,200 goats. The purpose of this study is to (1) evaluate the compositional and structural differences associated with the initial fuel break, and (2) quantify compositional shifts in herbaceous and woody vegetation caused by goat grazing over time. Results: Plots on fuel breaks and in adjacent wildlands exhibited significantly different species assemblages. Total herbaceous cover (both native and nonnative) was 92 times greater on fuel breaks than in adjacent chaparral-dominated wildlands and native shrub cover was 55.3 times greater in adjacent wildlands than on fuel breaks. Goats had a significant impact on reducing native and nonnative herb cover (87% reduction in cover, 92% reduction in height), but were ineffective at reducing the cover and height of most woody species such as Adenostoma fasciculatum, Eriogonum fasciculatum, Quercus berberidifolia, and Artemisia tridentata. However, goats were found to be effective in controlling nonnative grasses including Bromus diandrus and Bromus madritensis. Conclusion: Initial fuel break creation was effective at reducing wood biomass and height, simultaneously giving rise to an abundance and diversity of native and nonnative herbaceous species. Although targeted goat grazing was successful at reducing herbaceous biomass, it was ineffective at reducing woody biomass which is often one of the most important goals for fuel management in chaparral ecosystems.

The character of residential cooktop fires

A series of experiments was conducted to investigate the global preignition and combustion characteristics of corn oil heated in 9.7 to 26 cm diameter pans by a residential electric-coil element cooktop. For comparison, torch-ignited gasoline, heptane, and corn oil experiments were conducted in the same configuration except without the heating element energized. Heating oil on a typical electric cooktop leads to vaporization and generation of an aerosol cloud followed by autoignition. The evolution of the light-extinction coefficient before autoignition is measured and shown to be related to the pan diameter and initial fuel mass. Continued heating leads to enhanced vaporization of the burning oil and growing fires with the peak heat release rate, radiative heat flux, radiative fraction, and peak flame height larger than the gasoline fires regardless of pan diameter. CO and soot yields, and the CO/CO2 ratio are measured to decrease with pan diameter.

Heat Release Rate Characterization of NFPA 1403 Compliant Training Fuels

When using solid fuels for live fire training, NFPA 1403: Standard on Live Fire Training Evolutions requires that the materials be wood based. While the standard offers guidance on the type of fuels that are permissible for use in training, it offers little in the way of quantitative methods of selecting an appropriately sized fuel package. In order to examine the effects of fuel mass and orientation on heat release behavior, free burn heat release rate (HRR) experiments were conducted on twenty-one wood-based training fuel packages and twelve comparison furniture items. Training fuel packages demonstrated peak HRRs ranging from 1.0 MW to 3.6 MW, with the total energy release between 210 MJ and 1615 MJ. The furniture items exhibited peak HRRs between 0.9 MW and 3.7 MW, with the total energy release between 180 MJ and 995 MJ. A least-squares linear regression analysis indicated a good linear fit between total energy release and fuel mass burned among the training fuel packages (R$$^2$$ 2 $$=$$ = 0.98), suggesting that the effective heat of combustion is approximately constant at 14.2 MJ/kg. Generally, peak HRR increased as initial fuel mass increased, although the relationship was more variable, with the peak HRRs of similarly sized training fuel packages varying by nearly 1 MW. The results indicated that while total energy release was dependent largely on the initial fuel mass, peak HRR and peak burning duration were also dependent on the orientation and type of fuel in the fuel package. Wood-based training fuel packages were capable of producing peak HRRs comparable to individual items of furniture, although the total energy release was typically higher for the training fuel packages compared to corresponding furniture items.

Composite catalysts for the catalytic processing of fuel oil

The paper describes the catalytic cracking of heavy petroleum feedstock on catalysts based natural Taizhuzgen zeolite and Narynkol clay (Kazakhstan). Catalytic cracking was studied on fuel oil of the M-100 brand taken from the LLP Pavlodar Oil Chemistry Refinery (Kazakhstan). Air was added into the reaction medium. It was found that under optimal conditions, the conversion of the heavy residue of M-100 fuel oil reaches 46.2%, when cracking the initial fuel oil, the yield of the middle distillate fraction is 85.7 wt. % due to the content of 41.1 wt. % residual light gas oil in the resulting products. The optimal composite catalyst allows carry out the cracking of heavy oil residues without preliminary purification and with a high degree ofconversion to diesel fraction.

Fabrication and Assembly of the First Accident Tolerant Fuel Concept for TREAT Testing

Following the tragic events at the Fukushima Daiichi power plant in 2011, priority was given to increasing the accident tolerance of fuel systems for the current fleet of nuclear reactors. These enhanced Accident Tolerant Fuel (ATF) concepts include a wide variety of fuel and cladding materials, both as variants of the current Zircaloy-UO2 system and also as novel fuel and cladding concepts. In addition to testing at steady-state, prototypic, conditions within a nuclear reactor, performance of these ATF concepts in off-normal and transient conditions must be evaluated. The Transient Reactor Test (TREAT) facility at Idaho National Laboratory’s (INLs) Materials and Fuels Complex (MFC) was restarted in the Fall of 2017 and is well-suited to serve this purpose. September of 2018 marked the first fueled specimen to be tested in TREAT since its restart; testing of fuel specimens has been ongoing since then. Initial fuel tests focused on the traditional Zircaloy-UO2 fuel system in order to gain a more thorough understanding of operating characteristics of both the test vehicle system and also the interactions between the reactor and the experiment itself. These tests also served to commission new test vehicles using the well-characterized Zircaloy-UO2 system. The Separate Effects Test Holder, SETH Capsule, is a modular capsule designed such that it can support a wide variety of specimen geometries ranging from prototypic pressurized water reactor (PWR) fuel samples, heat sink based experiments, and more. The capsule itself is an additively manufactured titanium capsule, within which the experimental specimen is loaded. The SETH Phase I series of tests included five individual SETH capsules, each with a single fuel rodlet and instrumentation to measure temperature during irradiation in TREAT. Each fuel rodlet is representative of a fuel rod in a PWR, with UO2 in Zircaloy-4 cladding. In August of 2019, TREAT irradiated the first ATF candidate fuel, U3Si2. This marked the first transient test of an ATF concept and is part of a larger campaign that will irradiate a total of four capsules containing ATF concepts. This test campaign, SETH Phase II, built upon the previous SETH Phase I campaign with a nearly identical design except for the fuel rodlet itself. Two of the four SETH capsules contained U3Si2 fuel within Zircaloy-4 cladding, and the other two capsules contained U3Si2 fuel within SiC cladding. This paper reviews the design, fabrication, and assembly efforts resulting in the four qualified SETH capsules for TREAT irradiation of these ATF concepts.