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The thematic area studied in this paper considers environmental issues such as atmospheric pollution from the combustion of fossil fuels, and the environmental impacts from the generation of urban agricultural solid wastes. This study has estimated the potential for hydrogen and biogas production from solid urban waste (SUW) and wine waste from Bento Goncalves, which is a region in Brazil with the largest wine throughput and subsequent waste generation, thus providing a potential high-energy feedstock. The resulting hydrogen and biogas are assumed to displace the existing fuels in the local bus fleet. The analytical work consisted of three scenarios - scenario 1: production of biogas using SUW, sourced exclusively from the municipality of Bento Goncalves; Scenario 2: the possibility to supply SUW from Bento Goncalves and surrounding cities, to produce biogas; Scenario 3: the possibility to use wine waste and SUW for biogas production. Scenario 3 showed the greatest energy yield with 37.9 Gg of biomethane produced per year, which can supply the entire public bus fleet of Bento Goncalves. The resulting hydrogen production potential using steam reforming of biomethane is 1.09 E+08 Nm3H2.d−1 which can generate 2.62 TW h.year−1 of electrical energy, avoiding approximate emissions of 355 ktonCO2.year−1. These findings indicate value in the production of biogas from urban and agricultural wastes, especially for the generation of methane, hydrogen and useful energy outputs. Its production from renewable and clean sources contributes to the gradual transformation of an economy currently dependent on non-renewable resources into a circular and renewable economy.

Food wastage is a relevant problem all over the world. Remains of prepared foods increase the waste of resources due to energy and labor used in their preparation. However, food waste has a high energy potential can be converted in the form of methane via anaerobic digestion. This study evaluated the potential for recovery of energy contained in food wastes and presented a way to stablish the anaerobic digestion process using solely food waste. For this purpose, a prototype anaerobic digester was used of complete mixture with a volume of 408 L, 15% of total solids, temperature of 29.4 °C and an agitation system. The system was operated at steady state for 51 days in hydraulic retention time of 103 days, volatile solids and chemical oxygen demand of 0.80 g L−1 rd−1. According to the literature, the stabilization period presented typical inconvenient of food wastes digestions processes, that was solved monitoring at more frequent intervals the volatile fatty acids and with the maintenance of a compatible volume of organic load according with the size of the reactor. It was obtained a reduction of 90% in volatile solids and 82% in chemical organic demand. The methane production was 0.51 L.g−1CODc, 0.44 L.g−1VSc and volumetric yield of 0.32 L.L−1rd−1, representing 59% of the composition of the biogas. The adequate levels of agitation frequency, feeding load, temperature and C/N ratio were found in this study using the prototype anaerobic biodigester.

The containment in pig farming generates a large volume of effluent that can be treated by anaerobic digestion. To use the biogas generated in the process, in electricity generation, a better understanding of the variables involved is necessary. The objective of this study was the evaluation of biogas production parameters, power generation, performance of the generator group in the biogas conversion into electric energy and the avoided cost of electric energy of a pig farming property. Parameters of concentration, biogas production and consumption, and generation of electric energy were monitored, and the information generated was stored in a database. The results have indicated an average daily production of 443 m3, with an average of 0.10 m3 of biogas per pig and an average concentration of 68% methane. The average of electric energy generation was 324.5 kWh/day, and the efficiency of the generator was 17% with an average active power of 70 kW and a daily operation of 6.5 h. The avoided cost by self-consumption of electric energy generated in the property was R$ 13718.20, and during the monitoring period there was a total generation of electric energy of 70.5 MWh, of which 26.6 MWh were exported to the distribution network. The study also emphasizes that the appropriate choice of sensors and the methodology for monitoring and collecting data continuously could lead to an important data to use in correlated studies concerning generation of electricity from biogas.

Partial load operation of SI engines is conventionally achieved by the use of a throttle to control the airflow or air-fuel mixture into the engine. When the engine operates at partial load the throttle causes high pumping losses which has an effect on decrease of the engine efficiency. One of the possible ways to decrease the pumping losses during partial loads is to operate the engine under lean mixture condition. The limitation in this case can be misfiring of used fuel. The combustion limits can be extended by addition of hydrogen to the regular fuel. This work presents an analysis of use of hydrogen-methane taking into account aspects related to the efficiency and emission of pollutants. To carry out this study an experimental system composed of a SI engine was used. Two important differentials were used. First, the engine was supplied with simulated biofuels according to the typical biogas composition of the Brazilian landfills (Bio60); second, the system was operated in partial load, with the addition of H2, forming the HBio60 blend, in an attempt to increase efficiency and reduce pumping losses by increasing lambda value and variation in trottle position. The same aspects were evaluated with the engine operating with biogas composed of 95% of methane (Bio95) and in mixture with hydrogen (HBio95). The tests were performed at different ignition angles and air/fuel ratio. The results showed that adding H2 allows the combustion limits to be extended, with an effective increase of indicated efficiency. On the other hand, the reduction of NOx emissions was greater than 95% in the lean mixture provided by the presence of H2. The idea is to encourage change in the control algorithm of SI engines typically fueled with natural gas and use the H2-methane blends as fuel. Furthermore, diesel-powered buses in Brazil could be converted to SI gas engines without the loss of efficiency.

A preocupação com a preservação do meio ambiente e a necessidade de diversificação da matriz energética são alguns dos fatores que têm impulsionado a busca por energias alternativas. Nesse contexto, o presente trabalho analisou o processo de digestão anaeróbia de resíduos alimentares provenientes de um restaurante popular, observando o potencial bioquímico da geração de metano. O experimento consistiu no uso de reatores anaeróbios em regime batelada com volume de 250 mL, sendo 150 mL de volume útil à geração de biogás (headspace) e 100 mL remanescente preenchido nas proporções de 1:1 de substrato:inoculo, em relação ao teor de sólidos voláteis (gSVinoculo:gSVsubstrato). Os reatores foram operados por 30 dias sob temperatura constante em 30°C. Os resultados obtidos apresentam o teor de sólidos voláteis dos resíduos alimentares de 85,21% e uma relação C/N de 18,81. Foi possível alcançar uma produção específica de metano de 0,311 Nm³.kgSVr-1 e reduções de 23,58% para SV e de 81,27% para DQO.

In the last decades, the whole world has been feeling the effects of environmental pollution, especially air pollution in large cities, with the transport sector as a major contributor to this scenario. In this sense, Brazil presents 27 states with great potential for biogas generation from landfills through anaerobic digestion. Only in the year 2016, the calculations presented in this paper point to a methane production in landfills of 5.57E+09 m3. On the other hand, the high number of rivers and hydroelectric dams in the country makes possible the generation of electricity that reached 90.27 TWh in 2016. However, the water that is drained by the floodgates to control the level of the reservoirs becomes an interesting wasted energy source for other uses, such as the production of other clean fuel, hydrogen, through classical processes such as electrolysis. It is pointed out the possibility of producing 2.76E+06 tons of hydrogen only with the energy drained in these hydroelectric plants. These two fuels together can be used to fuel vehicles powered by the hydrogen–methane blends, like HBio95 and HBio60. The promise of harmful and CO2 emissions by focusing on mixture of gases has recently attracted the interest of vehicle manufacturers and transport operators. In this scenario, this work presents an analysis on the use of mixture of gases in the urban bus fleet of the 27 Brazilian states, using as energy source derived from secondary energy from Brazilian hydroelectric plants and biogas from sanitary landfills, comparing this scenario with the use of only methane from landfills or only H2 from hydroelectric plants, assessing issues such as pollutant emissions, engine performance and deployment facilities.

The purpose of this study was to evaluate the biogas production and the potential production obtained with the anaerobic digestion of cutting poultry carcasses. The carcasses were used to supply batch digesters with 8 liters of capacity of fermentation material. To perform this process, analysis content of total solids (TS) and volatile solids (VS) were performed. We used a system of three treatments, TRA (Treatment A) - 8% of ground chicken and 92% of water; TRB (Treatment B) - 8% of ground chicken, 20% of swine inoculum and 72% of water; TRC (Treatment C) - 13% of ground chicken, 20% of swine inoculum and 67% of water. The results were evaluated statistically showing that TRB treatment has shown better performance compared to the other two treatments, resulting in obtaining biogas at 0,3854 m³/kg TS and 0,4158 m³/kg VS, with an average production of methane (CH4) of 75.63%, thereby producing 0,2748 m³ of methane per kg of TS added and 0.2964 m³ of methan/kg VS-1 (???), with a hydraulic retention time (HRT) of 31 days. Key words: Anaerobic, methane, environment.

In this study, we compared cassava starch-based biodegradable polymers (PBMs) and glycerol (G) as additives used to increase biogas production from the co-digestion of swine wastewater (ARS). We chose to work with an inoculum comprising 40% (v/v) of the total volume of the reactor; this inoculum was obtained from a Canadian model digester for treating swine waste. In the anaerobic digestion process, batch reactors were used on a laboratory scale with a total volume of approximately 4 L and a working volume of 3.2 L. Three treatments were conducted to compare the efficiency of solid removal, the chemical oxygen demand (COD), and the production of biogas. The first treatment contained only swine waste; the second included the addition of glycerol at 1, 3, and 5% (w/v); and the third treatment included the addition of 1, 3, and 5% (w/v) of PBM residue in relation to the swine wastewater. From the results, it can be concluded that higher yields were obtained for the treatment with 3% PBM and 1% glycerol. Most treatments showed high removal rates of total solids and total volatile solids. Reductions lower than 70% were obtained only for treatments with PBM and glycerol at a ratio of 5%. O presente trabalho tem por finalidade comparar o potencial aditivo no aumento da produção de biogás de polímeros biodegradáveis a base de fécula de mandioca (PBM) e do glicerol, já comumente empregado com essa finalidade, ambos em co-digestão com água residuária de suinocultura. Utilizou-se como matéria-prima para produção de biogás, água residual de suinocultura, material plástico biodegradável produzido a partir de fécula de mandioca e glicerina bruta proveniente do processo de produção de biodiesel. Optou-se por trabalhar com 40% (v/v) de inóculo do volume total do reator. Para a condução do processo de digestão anaeróbia empregaram-se reatores com alimentação batelada de escala laboratorial de volume total de aproximadamente 4 litros e volume útil de 3,2 litros. Foram realizados 3 tratamentos visando comparar a eficiência da remoção de sólidos, demanda química de oxigênio e produção de biogás. O primeiro tratamento conteve apenas resíduo de suíno, o segundo a adição de glicerol em percentuais de 1, 3 e 5% (m/v) no mesmo resíduo e o terceiro a adição de 1, 3 e 5% (m/v) do polímero biodegradável a base de fécula de mandioca ao resíduo suíno. A partir dos resultados pode-se concluir que as maiores produções foram obtidas no tratamento de 3% de PBM e 1% de glicerol. A maioria dos tratamentos apresentou elevadas taxas de remoção de sólidos totais e sólidos totais voláteis. Apenas os tratamentos com PBM e glicerol na proporção de 5% obtiveram reduções inferiores a 70%.

This study aimed to evaluate the crude glycerol efficiency, from biodiesel production, biogas production with co-digestion of swine manure. The process was conducted with several concentrations of glycerol 0, 5, 10, 20, 30 and 40% (w/w) and swine manure with a concentration of 20, 40 and 60% (w/w) with pH 7.2 and 35°C. The fermentation periods were 21 and 30 days. Fifty ml of micro-reactors were used airtight coupled to a 10 ml syringe best condition to evaluate the production of biogas. Analysis was also performed to evaluate total solids reduction of solids mass in proposed treatments. Using a digestion system on a laboratory scale, is constituted by a 20 L reactor total volume, a gas meter and a reservoir for storage thereof, biogas production was evaluated for the sample with 5% of glycerol and the control sample (0% glycerol). With the aid of a gas chromatograph analyzed the methane content thereof. It was observed that the amount of swine manure has great influence on the production of biogas and the concentration in the sample yield was better with 60%. The crude glycerol together to swine manure at a rate of 5% w/w can be used as a supplement in anaerobic digestion, providing a significant increase in the production of biogas in its content of methane and removal of total solids. Moreover, it has been found that concentrations of 20, 30 and 40% (w/w) of glycerol were inhibitory at all studies, difficulties occur and little production of biogas. Chromatographic analysis of the sample with 5% glycerol was satisfactory in relation to methane content, showing 58.87% of CH4 in the biogas. Key words: Anaerobic digestion, methane, crude glycerol, swine manure.

The growth in the sugar and alcohol sector in Brazil has led to a significant increase in vinasse production, what aggravates the issue of its destination. Anaerobic biodigestion is an alternative for the treatment of this byproduct, presenting a relevant economic factor: its use as a source of energy. This work presents a technical–economic assessment of the electric energy production from vinasse biogas, obtained from an alcohol plant located in the state of Parana, Brazil, under three different operations. For each operation, it was considered five scenarios, varying from the most optimistic (best energy selling price) to the most pessimistic (worst energy selling price). The viability of the proposed project was calculated by using the Internal Rate of Return (IRR), Net Present Value (NPV) and Discounted Payback Period (DPP), showing that the plant is feasible for almost all scenarios. The energy production costs for the expected scenario for Operations 1, 2 and 3, were US$ 38.91 MW h −1 , US$ 56.32 MW h −1 and US$ 46.93 MW h −1 , respectively.

The generation of electric energy distributed throughout Brazil′s rural area contributes in the supply and logistics of energy production all over the country. This work aimed to analyze biogas production from swine waste and the generation of electric energy using biogas as primary source. Biogas was produced in Sao Miguel do Iguacu - Parana, Brazil, in a rural property which uses two biodigesters to produce biogas, whose electric conversion is performed in an engine-generator set of 100 kVA. With an average of 4672 housed animals, 554 Nm 3 day −1 of biogas were used in the generation of 847 kWh day −1 of electricity and the rest was incinerated in a flare. The average specific consumption of biogas in the engine-generator set was 0.68 m 3 kW h −1 and its efficiency was 22.21%. The cost of electric energy production using biogas was 0.12 R$ kW h −1 and the cost of the supplier′s electricity was 0.14 R$.kWh −1 . One can observe the economical feasibility of electricity production from biogas, even without receiving carbon credits.

One of the largest sources of energy available in rural and agro-industrial areas is the biomass, which is found in the form of vegetal and animal residues, such as crop leftovers, animal manure, energetic plantations and agro-industrial effluents. Such residues may be used by rural producers or agro-industries for direct burning, aiming to produce heat or biogas in biodigesters. Swine production generates a large amount of manure that causes environmental issues when not treated properly, due to its high levels of methane. When it is released in the atmosphere, it expressively contributes to the greenhouse effect. The co-generation of electric energy is still one of the ways to utilize biogas generated from food production. Apart from generating energy, it is also possible to sell carbon credits, what provides the producer with higher income. The present work aimed to determine the cost of installation, as well as the feasibility of biogas-based electricity production, by studying the scale economy in several scenarios of swine, biogas and electric energy production, sale or not sale of carbon credits, and investment costs with the estimated amortization period. One can notice that when carbon credits generate profit, production costs decrease and the LPV (Liquid Present Value) increases. Energy production only leads to loss when there is no additional income with carbon credits.

Uma das maiores fontes de energia disponíveis nas áreas rurais e agroindustriais é a biomassa. A mesma aparece na forma de resíduos vegetais e animais, tais como restos de colheita, esterco animal, plantações energéticas e efluentes agroindustriais. Estes resíduos podem ser utilizados pelo produtor rural ou agroindústria para a queima direta, visando a produção de calor ou produção de biogás em biodigestores. Junto às propriedades rurais onde há a atividade de suinocultura, ocorre a disponibilidade destes resíduos, caracterizando-se num grande potencial energético. Neste trabalho objetivou-se determinar o custo do biogás e a viabilidade de produção de eletricidade gerada a partir do mesmo numa propriedade rural, utilizando-se como equipamentos de conversão de biogás em eletricidade um motor de combustão interna acoplado a um gerador elétrico.

The objective of this article was to analyze the thermodynamic of a hybrid system, SOFC / ST (SOFC fuel cell and ST steam turbine). The fuel for the analysis was the gas methane (biogas) produced through the anaerobic digestion of the organic residues. The utilized methodology was the energy balance of the system SOFC / ST, considering the internal reforming of methane in the fuel cell, in a way to obtain its electric effectiveness. The result was compared to a conventional combined cycle of gas turbine and steam turbine (GT / ST) for powers between 10 MW and 30 MW. The efficiency of the hybrid system SOFC / ST varied from 61 to 66% in relation to the lower heating value of methane; and the efficiency of the combined cycle GT / ST varied from 41 to 55% within the same power interval. For distributed generation, the SOFC fuel cell is the most efficient technology.

One of the largest available sources of energy in the rural and agro-industrial areas is the biomass. It appears in the form of vegetable and animal residue, such as crop remains, animal manure, energy plantations and agro-industrial effluents. This residue can be used by the rural producer or agro-industry for direct burning, seeking the production of heat or biogas production in digester system. In agricultural properties of hog raising, the readiness of this residue occurs, being characterized in a great energy potential. This work aims to determine the cost and viability of electricity production, using biogas as fuel in group engine generator

The biogas is an alternative fuel produced by the biomass anaerobic digestion (organic waste) and is composed by methane and carbon dioxide. The shift in the composition of biogas is very important because it increases its use viability as biofuel. The remotion of carbon dioxide (CO 2 ) increases the methane (CH 4 ) concentration in biogas composition, making its heating value higher. A decrease of acid hydrosulphide (H 2 S) concentration reduces the corrosion produced during the use of biogas in thermal systems for the secondary energy production. This work aimed to develop a physical and chemical mechanism for biogas CO 2 remotion. The device developed was an absorption column stuffed of 250 cm high and 30 cm of diameter, using pipe of PVC rigid of 20 mm of diameter as stuff and water as solvent. Tests were done with inside pressure and gas flow in the column between 300 and 500 kPa and 190 and 670 cm 3 /s. The original biogas has a concentration of 33% CO 2 . With the utilization of the column absorption a reduction in CO 2 concentration of 15% was obtained, which showed an increasing of 57% in the lower heating value of biogas per unit of mass