Effect Of Biogas Research Articles

The effect of biogas and dimethyl ether on the thermal characteristics of a dual‐fuel diesel engine: A numerical study

AbstractThis investigation used the Diesel‐RK simulation program to carry out a numerical analysis of the effects that dual‐fuel mixes have on the combustion, performance, and emissions of a dual‐fuel diesel engine. It applied the multizone combustion model, and the controlling equations were solved for each individual combustion region. The engine characteristics were examined under the following scenario: it was initially powered by single‐fuel regular diesel (DF), then it switched to dual‐fuel use with 20% biogas, and then it was changed again with the use of 30% dimethyl ether (DME). On this basis, the mentioned biogas and DME ratios were used. The results showed that combustion pressure for the operation of 30% DME and 20% biogas was reduced by 2.45% and 9.57%, respectively, with respect to diesel fuel alone. The Sauter mean diameter (SMD) of the droplets was reduced by 12.6% for 30% DME and 16.2% for 20% biogas. Heat release and brake thermal efficacy (BTE) were reduced slightly with the use of biogas or DME in comparison with DF. The brake‐specific fuel consumption (BSFC) increased by 15.27% and 8.34%, with 30% DME and 20% biogas respectively due to the difference in the energy content of the tested fuels. Nitrogen oxide emissions decreased by 2% and 28% for the operation of 30% DME and 20% biogas, respectively. The summary emission equation (SE), which describes the combination of NOx and PM emissions, decreased by 4.23% and 5.40% with 30% DME and 20% biogas respectively. Based on the results, this paper recommends the use of 20% biogas with diesel rather than 30% DME. The current findings matched well with other scientists' results.

Biogas conditioning and digestate recycling by microalgae: Acclimation of Chlorella vulgaris to H2S-containing biogas and high NH4-N digestate and effect of biogas: Digestate ratio

Microalgae have the potential for biogas upgrading and digestate management as a downstream technology of anaerobic digestion. Through the acclimation to typical swine manure digestate with 1630 mg/L NH4-N, semi-continuous microalgae treatment was operated for biogas treatment with up to 4000 ppm H2S. Control of pH was necessary at high biogas to digestate liquid (G/L) ratios above 1 mol/L or 25:1 v/v (1 atm, 25 °C). Biogas decarbonation and desulfurization were achieved simultaneously with G/L ratios from 0.04 to 1.63 mol/L (1:1 to 40:1 v/v, at 1 atm, 25 °C), and nearly all methane remained in the upgraded biogas. Ammonia nitrogen as high as 930 mg NH4-N/L/d was removed at higher G/L ratios. The removed carbon and nitrogen were captured and assimilated into biomass at rates up to 13 g CO2/L/d and 540 mg NH4-N/L/d, respectively. The optimal phosphorus assimilation rate was 49 mg PO4-P/L/d obtained at the G/L ratio of 1.02 mol/L. These findings demonstrate that microalgal can treat high-H2S biogas and high-NH4-N digestate within a broad range of G/L ratios, including ratios that are similar to biogas and digestate generation ratios from swine manure digesters.

Active indole-3-acetic acid biosynthesis by the bacterium Azospirillum brasilense cultured under a biogas atmosphere enables its beneficial association with microalgae.

This study assessed, at the physiological and molecular levels, the effect of biogas on indole-3-acetic acid (IAA) biosynthesis by Azospirillum brasilense as well as the impact of this bacterium during CO2 fixation from biogas by Chlorella vulgaris and Scenedesmus obliquus. IpdC gene expression, IAA production and the growth of A. brasilense cultured under air (control) and biogas (treatment) were evaluated. The results demonstrated that A. brasilense had a better growth capacity and IAA production (105.7±10.3μgml-1 ) when cultured under biogas composed of 25% CO2 +75% methane (CH4 ) with respect to the control (72.4±7.9μgml-1 ), although the ipdC gene expression level was low under the stressful condition generated by biogas. Moreover, this bacterium was able to induce a higher cell density and CO2 fixation rate from biogas by C. vulgaris (0.27±0.08gl-1 d-1 ) and S. obliquus (0.22±0.08gl-1 d-1 ). This study demonstrated that A. brasilense has the capacity to grow and actively maintain its main microalgal growth-promoting mechanism when cultured under biogas and positively influence CO2 fixation from the biogas of C. vulgaris and S. obliquus. These findings broaden research in the field of Azospirillum-microalga interactions and the prevalence of Azospirillum in environmental and ecological topics in addition to supporting the uses of plant growth-promoting bacteria to enhance biotechnological strategies for biogas upgrading.

Effect of Biogas and Nutrient Recovery Technology on Methane Emissions and Nutrient Budgets

Effect of Biogas and Nutrient Recovery Technology on Methane Emissions and Nutrient Budgets

Analysis of the impact of gasoline, biogas and biogas + hydrogen fuels on emissions and vehicle performance in the WLTC and NEDC

The use of gasoline fuel in passenger cars has become popular once again due to the pollutants (oxides of nitrogen and particulate matter) diesel engines emit. In addition, research and development have been going on regarding the use of alternative and environmental fuels, such as biogas and hydrogen fuel, in passenger cars. In this study, a numeric engine model that was empirically validated with the engine test was used. Then, the effects of biogas and biogas + hydrogen fuels on fuel consumption and emissions in the Worldwide Harmonized Light Duty Test Cycle and New European Driving Cycle were analysed. Based on the findings, it was concluded that positive results in terms of emissions and fuel consumption could be obtained with a low ratio of hydrogen (5% as molar) added to biogas fuel. With the addition of hydrogen, 16.3% increase in fuel consumption with the use of biogas alone decreased to 12.1% and the increase in CO emissions decreased from 21.6% to 11.7% during NEDC cycle.

Techno-economic analysis of anaerobic digestion implementation in small Italian breweries and evaluation of biochar and granular activated carbon addition effect on methane yield

The aim of the work was to evaluate the techno-economic feasibility of anaerobic digestion implementation in small breweries located in the mountain area of Friuli-Venezia Giulia region (Italy). A territory-oriented approach was adopted, analysing the production of organic residues in local breweries and the potential methane production from each residue. An energy balance and a simplified dimensioning for anaerobic reactor installation at brewery scale was proposed, analysing actual energy consumption and the effect of biogas on plant energy balance improvement. Brewery spent grain, spent yeast, whirlpool residue and end-of-fermentation beer were identified as the main organic residues in the analysed plants. Biochemical methane potential tests revealed high methane potential of spent yeast, up to 486.9 NL CH4/kg VSadded, and spent grain, up to 356.2 NL CH4/kg VSadded. Granular activated carbon and biochar were added to selected tests to evaluate an eventual increase in methane yield; a noticeable effect was observed in particular on spent yeast, due to the enhanced microorganism activity and C/N ratio optimization. Co-digestion tests were performed on spent grain and spent yeast: a synergistic effect arose with a mixture of 70% spent yeast and 30% spent grain, where methane yield increased up to 447.7 NL CH4/kg VSadded. Electricity consumption was estimated as 130.6–148.9 MJ/hL, while heat need was 116.4–147.0 MJ/hL; it was showed that anaerobic digestion implementation, through a digester having 65 m3 volume, could provide up to 53.9% of electric and 64.4% of thermal need of the facility.

Effect of biogas on the performance and emissions of diesel engine fuelled with biodiesel-ethanol blends through response surface methodology approach

Fossil fuels consumption rate is an important issue which needs to be addressed regarding future perspectives in terms of the world overall energy requirement due to its exhausting nature and also due to environmental concern. Hence, more diversified research for alternate sources of fuel is needed, even to the extent of using only dual fuels; a mixture of high and low viscous fuel to eliminate diesel from compression ignition (CI) engines completely. In the present study, soya and soya ethanol blends are used as fuels for the CI engine. Besides the use blends in a diesel engine, the response surface methodology technique is also implemented for getting better responses. RSM results confirm that the use of dual fuel results in satisfactory engine performance and emission in a standard diesel engine without any modification in the engine. Blends, engine speed, air flow rate, and engine load are the input variables considered for attaining better BTE, VE, CO, HC, and NOx as the responses. From all the tested fuel blends considered in the study, the result shows that a blend of soya biodiesel with 8% blending with dual fuel mode at 1486 RPM, 49.5 mm manometer air flow, 6.27 kg engine load show an overall good engine performance. The performance and emission characteristics (BTE, VE, CO, HC, and NOx emission) are found to be 24.29%, 68.53%, 0.0715% volume, 51.6 ppmv and 1080.2 ppmv respectively.

Performance studies and emission analysis of azolla and corn husk biogas powered dual fuel mode compression ignition engine

ABSTRACTThe objective of this study is to analyze the effect of biogas on the operating characteristics and exhaust gas emissions of a CI diesel engine using a mixture of biogas and diesel. A 5.2 kW Kirloskar made single cylinder, water cooled, direct injection diesel engine is altered for biogas mode operation by connecting a venturi gas mixer at air inlet manifold. Azolla and corn husk feedstocks are employed to produce biogas. Biogas when used in engine reduced the ignition delay which resulted in reduced smoke and hydrocarbon emission, also improved combustion phasing, and increased the peak heat release rate. Around 1.58% increase in brake thermal efficiency was found for Azolla biogas mode operation.

Effects of biogas and raw slurries on grass growth and soil microbial indices

AbstractBiogas slurry is increasingly used as fertilizer. Earlier research was focused on plant growth and soil chemical properties, with only little information available regarding the effects of biogas slurry on soil and root microbial indices. For this reason, a 70 d pot experiment was conducted in which biogas and raw slurries obtained from six biodynamic farms were added to a soil. Italian ryegrass (Lolium multiflorum Lam.) was cultivated to investigate the effects on plant yield, N uptake (two harvests), soil microbial biomass, soil fungi, and root‐colonizing microorganisms. Biogas slurries increased the mean total above‐ground plant biomass by 66% and raw slurries by 35% in comparison to the control. The mean plant N‐uptake increased under biogas and raw slurry application by 166% and 65%, respectively, compared with the unfertilized pots. The effects of biogas and raw slurry application on soil microbial indices were similar except for the lower fungal biomass after biogas slurry amendment. In contrast to biogas slurries, the raw slurries significantly increased microbial biomass C and N by roughly 25% in comparison to the control. The application of biogas slurries significantly decreased the soil ergosterol content in comparison with raw slurry and control treatment, leading to a significantly lower ergosterol : microbial biomass C ratio. In the roots, biogas and raw slurry application significantly decreased the concentrations of the amino sugars galactosamine and glucosamine by 39 and 27%, respectively, but not that of ergosterol in comparison with the control. This was most likely due to a reduced colonization with arbuscular mycorrhizal fungi in the presence of highly available plant nutrients.

The study of simulated biogas on combustion and emission characteristics in compression ignition engines

New renewable fuels have been developed for diesel engines, contributing to the reduction of carbon emissions and to fuel security. However, the combustion characteristics of these fuels and emissions still remain unclear. A study to investigate diesel engine performance integrated with biogas and hydrogen has been carried out. Biogas is principally a mixture of methane (CH4) and carbon dioxide (CO2) along with other trace gases. In this study the simulated gaseous biogas (60% CH4 and 40% CO2 vol.) and hydrogen (2% vol.) fuels were fed into the engine intake manifold and diesel fuel was injected into cylinder as a pilot ignition fuel. The effects of biogas and hydrogen showed reduced PM compared with diesel combustion. In addition, up to 39 and 33% reduction in total particulate mass and smoke, respectively, was seen. However, there was a slight increase in particle number when gaseous fuel addition was used, where the particulate size distributions have moved towards the nucleation region thus benefitting the after-treatment systems. Reduced thermal efficiency was observed for the gaseous fuel addition.