Water Content In Fuel Research Articles

Prediction model of water content in surface dead fuel based on convolution neural network and meteoro-logical factors regression.

Water content of surface fuels is an important indicator of forest fire risk level and fire behavior, and the prediction model of which has a significant effect on fire risk prediction and management. Based on field meteorological factors of Quercus mongolica and Pinus sylvestris var. mongolica forests and water content data of dead fuels on the ground, we conducted the relative importance ranking of meteorological factors random forest and Pearson correlation analysis, and predicted water content of fuels using deeply learned convolutional neural network and meteorological factors regression. The results showed that water content of Q. mongolica fuels in the wild was significantly higher than that of P. sylvestris var. mongolica. The results of random forest showed that the factors that had significant effect on water content of fuel were humidity, temperature, rainfall, wind speed, and solar radiation, with the importance ranking from the largest to the smallest. Results of correlation analysis showed that temperature, humidity, and rainfall of current day had a significant impact on water content of fuels, and certain correlations were observed between meteorological factors. The prediction R2 of the convolutional neural network model for the surface fuel water content of Q. mongolica and P. sylvestris var. mongolica forest was 0.928 and 0.905, the mean absolute error (MAE) was 6.1% and 8.1%, and the mean relative error (MRE) was 8.9% and 4.2%, respectively. However, the R2, MAE, MRE of meteorological factors regression were 0.495 and 0.525, 30.5% and 39.5%, 52.1% and 32.6%, respectively. The precision of convolution neural network model was significantly higher than that of meteorological factors regression. Our results showed that the deeply learned convolutional neural network could provide some reference for the prediction of fuel water content in the future, and effectively support higher level forest fire management.

Fluidized bed combustion of high water content alcohol extracted herb residue and the impacts of blending wasted activated coke

Combustion of herb residues (HRs) for heat recovery is a good way for their utilization, but there exists such a problem as high concentration NOx emission in flue gas. The alcohol extracted herb residue (AEHR), one special type of HRs, was chosen as the object and was subjected to immediate combustion in a fluidized bed reactor to investigate the characteristics of its resulting NOx emission. The results showed that, most of the NOx in the flue gas was produced from the char nitrogen (CN); as the fuel water content increased, the NOx emission concentration exhibited a trend of first decreasing and then increasing; and a properly low combustion temperature inhibited the NOx emission upon the premise of ensuring full combustion. Air staging combustion was adopted to effectively control NOx: the NOx emission concentration in the flue gas was reduced to 296 mg·m−3 and the NOx emission reduction rate reached 46.51 % compared to conventional combustion. Co-combustion by blending wasted activated coke (WAC) into the AEHR helped both stabilize the combustion state and reduce further the NOx emission. When the blending ratio of WAC fell within a proper range of 20–30 %, the NOx emission concentration in the flue gas was as low as 231.4 mg·m−3. In addition to the dilution effect of the combustion flue gas of the blended WAC, the local reducing atmosphere caused by its incomplete combustion as well as its strong absorbability and catalytical effect was accountable for the further decrease of the NOx emission concentration.

Sodium polyacrylate hydrogel fixed bed to treat Water-Contaminated cloudy diesel

The applications of hydrogels in industry and academia are numerous and well known. However, the use of these cross-linked polymer materials is presented in this article with a particular purpose that is unexplored in the literature: to reduce water content from diesel aiming at meeting commercial specifications for turbidity in a continuous process. Currently, there are different processes in the industry to reduce water content in fuels, such as coalescing filters (for non-soluble water) and distillation (with high energy demand). However, this work showed the potential application of hydrogel as an alternative technology, being able to remove soluble water with ease of installation and low energy consumption. Sodium polyacrylate (SPA) hydrogel was chosen among others - polyacrylamide (PAAm) and poly(acrylic acid) (PAA) hydrogels - to treat cloudy diesel in a fixed bed. This polymer was characterized in terms of morphology and chemical composition and the swelling degree kinetics was studied considering different lyophilisation conditions and particle diameters. Also, the effect of type of external media and temperature on the equilibrium swelling degree were assessed. The lyophilized SPA hydrogel reduced the water content of diesel from around 630 ppm to near 100 ppm and the turbidity from Haze 6 down to Haze 1. These results demonstrate that the new technology has a potential use in petroleum refineries, storage and distribution facilities and also in small scale applications, such as in gas stations.

Seasonal variations in fire conditions are important drivers in the trend of aerosol optical properties over the south-eastern Atlantic

Abstract. From June to October, southern Africa produces one-third of the global biomass burning (BB) emissions by widespread fires. BB aerosols are transported westward over the south-eastern Atlantic with the mid-tropospheric winds, resulting in significant radiative effects. Ascension Island (ASI) is located midway between Africa and South America. From June 2016 to October 2017, a 17-month in situ observation campaign on ASI found a low single-scattering albedo (SSA) as well as a high mass absorption cross-section of black carbon (MACBC), demonstrating the strong absorbing marine boundary layer in the south-eastern Atlantic. Here we investigate the monthly variations of critical optical properties of BB aerosols, i.e. SSA and MACBC, during the BB seasons and the driving factors behind these variations. Both SSA and MACBC increase from June to August and decrease in September and October. The average SSA during the BB seasons is 0.81 at 529 nm wavelength, with the highest mean ∼ 0.85 in October and the lowest ∼ 0.78 in August. The absorption enhancement (Eabs) derived from the MACBC shows similar trends with SSA, with the average during the whole of the BB seasons at ∼ 1.96 and ∼ 2.07 in 2016 and 2017, respectively. As the Eabs is higher than the ∼ 1.5 commonly adopted value by climate models, this result suggests the marine boundary layer in the south-eastern Atlantic is more absorbing than model simulations. We find the enhanced ratio of BC to CO (ΔBC/ΔCO, equal to BC/ΔCO as the BC background concentration is considered to be 0) is well correlated with SSA and MACBC, providing a simple way to estimate the aerosol optical characteristics in the south-eastern Atlantic. The exponential function we proposed can approximate SSA and MACBC with BC/ΔCO, and when BC/ΔCO is small it can capture the rapid growth of SSA as BC/ΔCO decreases. BC/ΔCO is influenced by combustion conditions and aerosol scavenging. From the analysis of the location of BB, the primary source fuel, the water content in the fuel, combined with the mean cloud cover and precipitation in the transport areas of the BB plume, we conclude that the increase in BC/ΔCO from June to August is likely to be caused by burning becoming more flaming. The reduction in the water content of fuels may be responsible for the change in the burning conditions from June to August. The decrease in BC/ΔCO in September and October may be caused by two factors, one being a lower proportion of flaming conditions, possibly associated with a decrease in mean surface wind speed in the burning area, and the other being an increase in precipitation in the BB transport pathway, leading to enhanced aerosol scavenging, which ultimately results in an increase in SSA and MACBC.

Air preheating and exhaust gas recirculation as keys to achieving an enhanced fuel water content range in stratified downdraft gasification

The strict fuel water content requirements inhibit the breakthrough of small-scale stratified downdraft gasification CHP plants. The present work was conducted to enlarge the allowable fuel water content range in a wood-chip-driven downdraft gasifier with a nominal fuel load of 90 kW. Specifically, the range was enhanced to include wetter and drier fuel using the methods of air preheating and continuous exhaust gas recirculation (EGR). In this study, three dry (i.e., 8 m%, 5 m%, 2 m%) fuel water content levels were tested with EGR rates ranging from 0 to 62.5 l∙min−1, and three wet fuels (i.e., 8 m%, 17 m%, 21 m%) were tested at three different air temperatures (i.e., 20 °C, 60 °C, 100 °C). Three novel findings were obtained: (1) Air preheating successfully shifted the flame front upward, enlarging the applicable maximum fuel water content from 18 m% to 21 m%, but the gas quality slightly worsened in terms of LHV and tars. (2) The application of EGR lowered the fuel water content limit from 8 m% to 2 m% and even increased the cold gas efficiency and reduced the tar content in the product gas. (3) The evaluations revealed that the flame front must be positioned within a relatively narrow range and close to the reactor throat to ensure steady operation. A safe and long-lasting operating point for each fuel water content was determined. The results of this work indicate that an enhanced fuel flexibility will be possible in stratified downdraft gasifiers in the near future.

Deviations and errors review on measuring and calculating heavy fuel oil consumption and fuel stock onboard vessels equipped with volumetric fuel consumption flowmeters

A common way of measuring heavy fuel oil consumption on board a vessel is to use volumetric fuel flow meters installed at fuel systems inlets for each of the major fuel consumers. At each stage of the fuel processing cycle, certain mass fuel losses or deviations and calculation errors occur that are not counted accurately into fuel consumption figures. The goal of this paper is to identify those fuel mass losses and measuring/calculating errors and perform their quantitative numerical analysis based on actual data. Fuel mass losses defined as deviations identified during the fuel preparation process are evaporation of volatile organic compounds, water drainage, fuel separation, and leakages while errors identified are flow meter accuracy and volumetric/mass flow conversion accuracy. By utilizing statistical analysis of obtained data from engine logbook extracts from three different ships numerical models were generated for each fuel mass loss point. Measuring errors and volumetric/mass conversion errors are numerically analyzed based on actual equipment and models used onboard example vessels. By computational analysis of the obtained models, approximate percentage losses and errors are presented as a fraction of fuel quantity on board or as a fraction of fuel consumed. Those losses and errors present between 0,001% and 5% of fuel stock or fuel consumption figures for each identified loss/error point. This paper presents a contribution for more accurate heavy fuel oil consumption calculation and consequently accurate declaration of remaining fuel stock onboard. It also presents a base for possible further research on the possible influence of fuel grade, fuel water content on the accuracy of consumption calculation.

Evaluation and extension of the load and fuel flexibility limits of a stratified downdraft gasifier

The small-scale biomass gasifiers' application for CHP in conventional households is still inhibited by their inflexible operating conditions, which do often not meet the user's desires of yielding varying loads and switching between any available fuels. Thus, the present work aims to identify the gasifier's flexibility limits by investigating sudden steps in load and fuel water content in a woodchips-driven, stratified downdraft gasifier with a 90-kW nominal fuel load. In contrast to former work, the focus was set on the transient processes, during which the product gas composition and the gasifier bed temperatures were continuously monitored. The evaluations revealed that the gasifier produces a continuously high and almost load independent product gas quality in the range of ±20% of the nominal load, even throughout sudden load changes. Steps of 8 m% fuel water content from dry to wet fuel turned out to be the maximum manageable step size without additional measures. Switches from wet to dry fuel required the previously introduced methods of exhaust gas recirculation and water injection. These methods successfully enlarged the allowable step to over 8 m% fuel water content. These promising results will allow a future more versatile and user-optimized operation of stratified downdraft gasifiers.

Feasibility Study of Emission Reduction on Marine Engine with Variation of Emulsified Water Concentration and Turbocharger Compression Ratio

The characteristics of black carbon and nitrogen oxide reduction versus the water content of emulsion fuel were studied by numerical methods, and a method of reducing fuel consumption was achieved by adjusting the turbocharger compression ratio. The results of the combustion period characteristics, versus the three types of emulsion fuel and the turbocharger compression ratios, shows that the combustion period is shortened in the order of CR00 > CR01 > CR02 > CR03, according to the compression ratio of the turbocharger. As the fuel water content increases, the combustion period is shortened in the order of EMDO16 < EMDO13 < EMDO10. The nitrogen oxide and black carbon reduction was because the combustion period increased, with increasing compression ratio, while the combustion period was shortened, with increasing moisture content of emulsion fuel. This also caused is an increase in the combustion pressure and a shortening of the combustion period, due to the expansion of the volume, in turn due to the micro-explosion of water. This may be due to the shortening of the post combustion period and the reduction of black carbon emissions. In addition, combustion was accelerated in the order—CR00 > CR01> CR02> CR03. By optimizing the water content of the emulsion fuel and turbocharger compression ratio, while considering the exhaust emission and combustion state, reduction of the fuel consumption rate and output improvement are shown.

The Effect of Water Contents to Diesel Fuel-Water Emulsion Fuel Stability

The declining world oil and gas reserves along with increasing gas emissions from fossil fuel consumption has received serious attention as an urgent problem worldwide. The alternative solution to the problem uses emulsified fuel which is expected to provide better combustion efficiency and will contribute to emission reductions, such as NOx and particulate matter (PM). The one of most important factor in emulsion fuel is its stability. In this work, the effect of water contents to stability of diesel-water emulsion fuels has been investigated. The stability of emulsion fuel related to coalescence and sedimentation formation. The diesel fuel-water emulsification process was carried out in a standard stirred tank consisting of a cylinder tank (93 mm in diameter) and Rushton disk turbine (40 mm in diameter). Materials used consist of diesel oil (Pertamina DEX), demineralized water, surfactants (Lecithin, Triton X-100 and Tween 80). The surfactant used is a mixture of Lecithin - Triton X-100 (76.6%: 23.4%) and Lecithin - Tween 80 (45.5%: 54.5%) at 1% total volume of emulsion. The impeller set in constant speed at 1900 rpm. To reduce emulsification energy consumption, water is added gradually into the tank at 2 mL/min of flowrate. Water content varies at 5%, 10%, 20%, and 40% by total volume of emulsion. Physical properties of emulsion fuel such as viscosity and density at room temperature were investigated periodically. The characterization of emulsion fuel stability was measured by slope value of absorbance ratio at wavelength 450 nm and 850 nm. Sediment formation was periodically by visual observation as emulsion phase percentage. Emulsion droplet size was measured by Dynamic Light Scattering (DLS) method. Physical properties of emulsions such as density and viscosity tend to constant value in order of time. Emulsion fuel with 5% water content has the largest volume of emulsion phase in the rest of time, 83 % for L-T emulsion fuel and 95% for L-Tx. The lowest slope value shown by 5% emulsion fuel water content, -8.657×10-5 for 5% L-T emulsion fuel and -2,084 × 10-4 for 5% L-Tx emulsion fuel. Droplet size measurement of emulsion shown that different amount of added water caused the different droplet size of emulsion.

Effect of dust deposition on spectrum-based estimation of leaf water content in urban plant

Abstract Hyperspectral technology has equipped large-scale efforts to estimate leaf water content. In an urban environmental context, these efforts may be hampered by dust deposition on leaves. However, the influence of dust deposition on the accuracy of estimating water content is still to be elucidated. This study aimed to comprehensively analyze the influence of dust deposition on the spectrum-based estimation of water content in Shanghai, China. We measured the amount of dust deposition, water content, and the spectrum of 707 sample leaves. We then derived the spectrum-based indexes of water content and assessed the influence of dust deposition on the performance of such indexes in estimating leaf water content. The results revealed that dust-polluted leaves retained the correlations between the observed water content indexes, which includes Equivalent Water Thickness (EWT) and Fuel Water Content (FWC), with spectrum-based indexes. However, these correlation coefficients dramatically varied with the changes in dust deposition amount. EWT had weaker while FWC got stronger correlation coefficients with spectral indexes for dusty leaves compared with clean cases. The spectral indexes were correlated with EWT at a consistently stronger extent than with FWC, suggesting an advantage of using EWT over FWC to represent the leaf water content. The correlations between EWT and spectral indexes were stronger with leaf samples from the same tree species compared with the case of using leaf samples from mixed species. These findings can strengthen the understanding of the influence of dust pollution on leaf water content estimation using spectral indexes.

An Effect of Biosolar-Water Emulsion on Small Marine Diesel Engine

This study aims to analyze the effect of water/biosolar emulsion fuel on the performance of engine diesel used in small capacity diesel engines. The fuel used is a mixture of biosolar 20% which is added 10% and 15% water (b20,WDE 10%, WDE 15%) which will be compared with dexlite fuel and biodiesel 20% (b20). Measurement of engine performance with various fuels was carried out in accordance with IMO marine engine regulation tier 3. The water-emulsified diesel could be used in the light-duty small diesel engine without modifications. The result shows that the net diesel fuel consumption and the exhaust gas temperature decreased with increasing water content of fuels over the investigated loading range.Performance produced by DWE 10% and 15% will been reduce Power, and Torque at each RPM. In detail, DWE 10% has better results than the DWE 15%. In the NOx emission test results, the use of water/biodiesel emulsified fuels 10% and 15% can reduce NOx emissions.

Optimization study of the produced electric power by SOFCs

In this work, an optimization study of the delivered power density by the solid oxide fuel cells is presented according to a thermodynamic model. The power density is defined by the current density, the Nernst potential and the three losses: concentration, activation and ohmic. A comparison between the Tafel and Butler-Volmer formulations was performed to quantify the activation loss. A program in FORTRAN language was developed locally for the resolution of the mathematical equations representing the used physical model. The obtained results show that the SOFCs power density is inversely proportional to the anode thickness, electrolyte thickness and cathode thickness. The optimum fuel water content ensures the maximum power density is 6.25%. The cell power density is proportional to the oxygen concentration in the oxidant, the operating temperature and the operating pressure.

Spatially resolved chemical species concentrations above the fuel bed of a small grate-fired wood-chip boiler

This work concerns the first stage of combustion in a small, air-staged, wood-chip boiler because comprehensive experimental data on the release of wood-volatiles during thermal conversion of solid biomass on grates are necessary to provide reliable data for the validation and optimization of fuel bed models and gas phase combustion models. Despite this importance, data especially from small-scale boilers are rare. This work provides detailed information about the spatial distribution of gaseous species, water and tar above the fuel bed of a commercial boiler with a nominal heat output of 40 kW. Furthermore, the influence of the primary air ratio and the wood-chip moisture on the fuel gas composition and the quantity of fine particulate matter emissions were investigated. Fuel gas volume fractions were: 16.6% CO, 3.6% H2, 1.8% CH4, 6.3% CO2, 0.2% O2, 28.3% H2O, 43.2% N2 for wood-chips with a fuel water content of 12% and a primary air ratio of 0.25. The corresponding tar content and the lower calorific value amounted to 78 g m−3 at standard temperature and pressure (STP) and 5.14 MJ kg−1, respectively. The locally different concentration of species and temperature above the fuel layer resulted from the fuel bed movement. Strong gradients in species fraction were detected in direction of the fuel flow while species fraction gradients perpendicular to fuel bed movement were marginal. Particulate matter emissions of the investigated boiler were 7 mg m−3 (at STP and O2 volume fraction of 13% in the dry exhaust gas) with aforementioned testing conditions.

Mathematical modeling of extra-heavy oil gasification at different fuel water contents

In this study, a kinetic model for extra-heavy oil gasification has been developed. It is a zero dimensional, steady state model based on global reaction kinetics and is capable of predicting performance parameters of the process. Effects of parameters, including fuel water content and equivalence ratio on tar yield, gasification temperature and performance parameters such as syngas higher heating value (HHV), carbon conversion efficiency (CCE), cold gas efficiency (CGE) have been discussed. The results indicate that the higher equivalence ratio is more favorable for carbon conversion and tar cracking; however, it lowered gas caloric value and cold gas efficiency. It is also found that the higher carbon conversion and lower tar yield are possible at higher fuel water content. The model is validated by experimental and thermodynamic data and found relatively to be in good agreement.

Use of Natural Resin to Reduce Water Content in Diesel Fuel

We propose using a wood resin to remove water from diesel fuel. We have studied the effect of the quantity of resin used and its contact time with the fuel on the water content in the fuel. We have also determined the changes in density, kinematic viscosity, electrical conductivity, flash point, and heat of combustion for diesel fuel after contact with the resin. Under optimal conditions, the heat of combustion of the fuel increases by 633 J/g, and the water content is reduced by 69%.

Quantification of fuel moisture effects on biomass consumed derived from fire radiative energy retrievals

Satellite based fire radiant energy retrievals are widely applied to assess biomass consumed and emissions at regional to global scales. A known potential source of uncertainty in biomass burning estimates arises from fuel moisture but this impact has not been quantified in previous studies. Controlled fire laboratory experiments are used in this study to examine the biomass consumed and the radiant energy release (Fire Radiative Energy, FRE, (MJ)) for western white pine needle fuels burned with water content (WC, unitless) from 0.01 to 0.14. Results indicate a significant relationship: FRE per kilogram of fuel consumed = −5.32 WC + 3.025 (r2 = 0.83, n = 24, P < 0.001) and imply that not taking into account fuel moisture variations in the assumed relationship between FRE and fuel consumed can lead to systematic biases. A methodological framework to derive a revised formula that enables the estimation of biomass consumed from FRE, which explicitly takes into account fuel water content, is presented.

Water Content in Biodiesel, Diesel, and Biodiesel–Diesel Blends

Biodiesel has a higher affinity toward moisture content than petroleum diesel, and the water retaining capacity of biodiesel is higher than diesel. The water content in fuels can be classified in free, emulsionated, and soluble water. High water content in biodiesel and diesel can cause problems such as water accumulation and microbial growth in fuel tanks and transportation equipment. Currently, there is a lack of information on water absorbance in biodiesel and biodiesel/diesel blends. Experiments were conducted to determine the water absorbance of biodiesel and biodiesel–diesel fuel blends evaluating the temperature and blend ratio parameters. Soluble water in biodiesel ranged from (1500 to 1980) mg·kg–1 in the temperature range of (283.15 to 323.15) K, which was 10 to 15 times higher than diesel. Results also showed that, at constant relative humidities, biodiesel absorbed 6.5 times more moisture than diesel. The presence of free and/or emulsionated water in biodiesel and blends was determined through turbidity experiments.

H 2 rich syngas by selective CO 2 removal from biomass gasification in a dual fluidized bed system — Process modelling approach

A process model of dual fluidized bed gasification is presented based on mass- and energy balances. The model further covers the evaluation of thermodynamic equilibrium states. The gasification is investigated for the special case that CaO/CaCO 3 is used as bed material allowing selective transport of CO 2 from the gasification reactor to the combustion reactor by repeated carbonation and calcination. Experimental data are used to determine the model parameters. An empirical approach towards the kinetics of fuel conversion allows prediction of process behaviour at varied fuel water content. The selective transport of CO 2 results in high H 2 contents in the produced syngas. The lower operating temperatures in the gasification reactor increase the efficiency of energy conversion. The results are in agreement with experimental data and show the thermodynamic limitations of the technology.

Fluidized Bed Steam Gasification of Solid Biomass - Performance Characteristics of an 8 MWth Combined Heat and Power Plant

The work focuses on a dual fluidized bed gasification technology that is successfully operated for combined heat and power production at a scale of 8 MWth in Guessing/Austria since 2002. The reactor concept consists of a circulating fluidized bed system with a steam-fluidized bubbling bed integrated into the solids return loop. Accompanying the operation of the commercial scale plant, parameter models have been developed and validated by comparison to measured data. As the models naturally fulfill mass and energy balances, the simulation also allows the validation of measurement data. The behaviour of the plant is studied by carrying out variations of selected parameters. Evaluation of different plant operation cases yields correlations between process variables. The solids circulation rate is shown versus riser exit velocity. Fuel water content and gasification temperature significantly influence global plant performance. Simulation predicts the efficiency of the existing power plant in optimized operation. Finally, part load behaviour is investigated and performance maps of the CHP plant are presented. High fuel water content at high gas engine load results in high gas velocities in the riser (erosion limit) and higher heat ratio in the produced energy. It is concluded that CHP-concepts based on fluidized bed steam gasification can reach high electric efficiencies and high overall fuel utilization rates even at small plant capacities of about 10 MWth.

Dynamic models of aquiferous content of living fuels

Forest fire occurrence is closely relative with fuel water content. There are a lot of research about dead fuels, but forest fuels consist of both dead fuels and living fuels. Each large fire occurrence has a good relationship with living fuels. Especially living fuels can influence the production and development of big forest fire, so, we selected Tahe, in Daxingan Mountains, as observation site. According to actual data, we can establish a set of models of different living fuel water content variation with linear-regression method.