Methane production by fermentation is a complex biochemical process, in which micromolecular organic substances are broken down by anaerobic bacteria into simple stabilized chemicals—mainly methane CH4 and carbon dioxide CO2. The organic matter of the slurry consists mainly of fats, proteins and carbohydrates. As a result of biochemical changes in the process of anaerobic decomposition, some of this matter is mineralized to simple chemical compounds. Cattle and pig husbandry offers enormous potential for useable biogas plant substrates. As a result of the constantly increasing amounts of animal husbandry products, and increasingly stringent environmental protection requirements aimed at reusing natural fertilizers, it is necessary to look for alternative processing methods. The need for efficiency in obtaining biogas from substrates (e.g., manure) was met by the laboratory stand presented in this article, for which the Polish patent No. 232200 was obtained. The new technology also allo... [more]

Combustion is the most commonly used technology to produce energy from biomass; nevertheless, there are still thermal efficiency problems in current biomass combustion furnaces and a lack of knowledge about the properties of residual biomasses that could be used as fuels. Aiming to contribute to knowledge of the potential of residual biomass for energy generation, this work reports on the implementation of a 2D computational model to study the combustion performance of several solid biomass fuels, and its application in the analysis of Lippia origanoides bagasse combustion. The model uses an Eulerian−Lagrangian approach; in the continuous phase, governing equations are solved, and in the dispersed phase, particles are tracked and the mass, momentum, species and energy transfer between the phases are calculated. The model was validated against experimental data from a combustor fueled by three biomasses: wood pellets, olive stone and almond shell. The results show deviations of less tha... [more]

In this study, biomass−specific gasification data is experimentally collected for numerical simulations of fixed−bed reactors. Since biomass properties vary, it is crucial to have characteristic biomass data. Extensive data is collected to determine an appropriate description of specific biomass behavior, including basic data (e.g., heating value, size, densities, ultimate and total analysis etc.), biomass pyrolysis and heterogeneous gasification reaction data. Heterogeneous reactions were comparatively investigated in the forms of powder, particles, and a fixed−bed. The powder was investigated in depth with CO2, O2, and H2O (gas fraction 5−20 vol.%; temperature CO2, O2 and H2O, respectively, at 730−790 °C, 360−405 °C, 720−780 °C), while particle reactions and fixed−bed reaction were only studied with CO2. A model description for a fixed−bed batch reactor was applied, modified, and compared to experimental fixed−bed batch reactor results. This study concludes that determining the appro... [more]

Biomass gasification is an attractive technology and one of the pathways for producing hydrogen. Due to the variable seasons and low calorific value of biomass, the addition of coal in the gasifier is suggested because coal has a high calorific value and carbon-to-hydrogen ratio. In general, the gaseous product obtained in gasification always contains a high amount of carbon dioxide, therefore, the co-gasification of biomass and coal should integrate with the calcium looping carbon dioxide capture process to provide purified hydrogen. In this work, the model of the co-gasification of biomass and coal integrated with the calcium looping carbon dioxide capture process was developed through an Aspen Plus simulator. The developed model was used to analyze the performance of this process. The sensitivity analysis demonstrated that increasing the gasification temperature, steam-to-feed (S/F) ratio, calcium oxide-to-feed (CaO/F) ratio, and regenerator temperature could improve hydrogen produc... [more]

Catalytic upgrading of fast pyrolysis bio-oil from two different types of lignocellulosic biomass was conducted using an H-ZSM-5 catalyst at different temperatures. A fixed-bed pyrolysis reactor has been used to perform in situ catalytic pyrolysis experiments at temperatures of 673, 773, and 873 K, where the catalyst (H-ZSM-5) has been mixed with wood chips or lignin, and the pyrolysis and upgrading processes have been performed simultaneously. The fractionation method has been employed to determine the chemical composition of bio-oil samples after catalytic pyrolysis experiments by gas chromatography with mass spectroscopy (GCMS). Other characterization techniques, e.g., water content, viscosity, elemental analysis, pH, and bomb calorimetry have been used, and the obtained results have been compared with the non-catalytic pyrolysis method. The highest bio-oil yield has been reported for bio-oil obtained from softwood at 873 K for both non-catalytic and catalytic bio-oil samples. The r... [more]

The course of pyrolysis of pea husks was studied. It was stated that the compaction of a sample during its pyrolysis causes an almost two-fold increase in the content of hydrocarbons in the composition of volatile products in the temperature range of 350−470 °C. Low density polyethylene (LDPE), novolac, and coal tar pitch (CTP) wastes were added to feedstocks in the amount of 2 wt% in order to decrease the contribution of saturated and unsaturated hydrocarbons along with oxygen-containing compounds in volatile products. The analysis of the obtained products of pyrolysis was conducted using the techniques of thermogravimetry/Fourier transform infrared spectroscopy (TG/FT-IR), attenuated total reflectance (ATR) and ultraviolet (UV)-spectroscopies, gas chromatography-mass spectrometry (GCMS), X-ray diffractions (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). It was determined that pitch took the first place in a series of effectiveness in decreasing... [more]

An energy production system that combines biomass and fuel cells produces much energy with minimal environmental impact. However, the hydrogen sulfide (H2S) contained in gasified biomass degrades fuel cell performance, thus negating the advantages of this combination. In this study, the removal of H2S by adsorption after biomass gasification was investigated. Metal oxides with high adsorption performance are common H2S adsorbents. However, they have a significant environmental impact in terms of metal depletion, which is an environmental impact indicator. Therefore, neutralized sediment materials from mine drainage treatments can be used as H2S adsorbents. A previous study found that the adsorption performance of H2S adsorbents is equivalent to that of metal oxides, especially in the high-temperature zone (300 °C), and the environmental impact is considerably lower than that of metal oxides. However, because the neutralized sediment is a powder (Φ 4.5 μm on average), there is a possibi... [more]

Based on the decision of representatives from the West African region and feedback from locals in Togo, an advanced continuous-feed, forced-draft, biomass cookstove named “Apeli” was developed. The stove was tested in modified ISO measurements based on the ISO 19867-1:2018 standard. This included a long shutdown operation using wood pellets and short shutdown operations using wood pellets, bamboo pellets, wheat straw pellets and palm kernel shells. Due to the fast shutdown capability, the short shutdown was chosen for more realistic results using this stove type. For cold start and long shutdown operation using wood pellets, the thermal efficiency is determined as 44.1% at a 1116 W power output by emitting 0.272 g CO and 17.2 mg PM 2.5 per MJd at high load. At low load, the efficiency is 38.0% at a 526 W power output by emitting 1.1 g CO and 45.1 mg PM 2.5 per MJd. Due to a misinterpretation of the standard, the burnout duration of the tests with long shutdown is approx. 1.5 min shorte... [more]

Mercury is considered one of the most harmful ecotoxic elements. A main source of its anthropogenic emissions is fuel combustion. For fuels with a high mercury content, costly methods are required to remove mercury from the flue gases. The solution to this problem is to remove mercury from the fuel before combustion. This can be achieved by a mild pyrolysis process. Solid fuel samples with relatively high mercury content were examined. These included waste (refuse-derived fuel, paper, sewage sludge, and rubber), waste wood biomass (hornbeam leaves, pine and spruce bark), and six coal. The mild pyrolysis process was performed at 300 °C in an argon flow of 500 cm3/min. The residence time was 30 min. Proximate and ultimate analysis (including mercury content) was conducted for raw fuels and chars. The process allowed a significant reduction in mercury content from 36 to 97%. Mercury was most easily removed from biomass and waste with the most difficult being from coal. The effectiveness o... [more]

Gasification is considered a clean and effective way to convert low quality biomass to higher value gas and solve various waste utilization problems as well. However, only 80% of biomass is converted through thermal processes. The remaining part is char, which requires more time for conversion and in that case reduces the efficiency of gasifier. Seeking to optimize the process of gasification, this work focuses on the intensification of residual char gasification in a gasifier. For this purpose, three different types of char prepared from wood, sewage sludge and tire were examined under different conditions in a lab-scale gasification setup. Results showed that the air flux increase from 0.11 kg/(m2s) to 0.32 kg/(m2s) intensified the gasification process and the gasification rate increased from 0.8 to 2.61 g/min with the decrease of duration of wood char gasification by 72%. An additional introduction of pyrolysis gas into the char gasifier led to decreased bed temperatures, but the ga... [more]

Identifying a modeling procedure of biomass thermal decomposition that is not only simple enough to implement and use, and computationally efficient, but also sufficiently accurate for engineering design activities, and with a spectrum of applications as broad as possible is a very difficult task. The authors propose a procedure which consists of two main stages: (a) the static modeling phase with the purpose of generating the algorithm (macro functions) that supplies a Computational Fluid Dynamics (CFD) model with specific input data (source/sink terms and local material properties) and (b) the dynamic modeling phase, where the CFD model is bi-directionally coupled to the external biomass decomposition model in the form of a User-Defined Function (UDF). The modeling approach was successfully validated against data obtained from single particle decomposition experiments, demonstrating its applicability even to large biomass particles, under high heating rates and combusting conditions.

One of the tools to attain the goal of climate-neutrality by 2050 by the European Union is increasing the share of renewable energy sources (RESs) in the energy mix of member states. A major part of the future bioenergy mix is to be played by biomass. As many hazards have been pointed out when using forest biomass, particular attention is paid to the potential of agro biomass. However, as agro biomass is sourced mostly locally, the supply may not be sufficient to meet the growing demand. Therefore, international trade (including overseas) might become increasingly important to meet the EU renewable energy targets. In this context, it is seaports that may play a major part in developing biomass supply chains. The main purpose of the article is to fill the research gap by identifying the pros and cons for the development of biomass sea-based supply chains through secondary ports and specifying their relevance from the perspective of major stakeholders in the context of decarbonization pr... [more]

Tanzania has a high rural population, of which many rely on off-grid diesel generators to produce electricity. The focus of this paper is to assess if the waste biomass residues in Tanzania have sufficient energy potential to produce renewable electrical energy for small-scale electricity generation using off-grid diesel generators coupled with anaerobic digestion (AD) and/or gasification. The gaseous fuel produced can then be used to substitute diesel fuel used in small-scale dual fuel diesel gen-sets; thus, providing more affordable electricity whilst reducing dependency on fossil fuels. The biomass waste streams estimated are those arising from agriculture, forestry, livestock, and urban human waste. To answer this question, the energy potentials of each of these biomass waste streams are quantified, followed by further calculations to determine the electricity generation capacity per stream based on overall efficiencies of 10 and 25%. The results show that combined these waste stre... [more]

This paper deals with the state and perspectives of bioenergy development in the context of exploiting the potential of available natural resources. We analyse the economic benefits of transitioning to alternative biofuel within the research task in cooperation with the Vojany black coal power plant. Within the applied methodology, a non-parametric data envelopment analysis method was used to confirm the most economically efficient types of fuels used in the combustion process. The assumption of fuel efficiency was confirmed by testing fuel combustion combinations directly in the power plant. The transition to 100% combustion of solid recovered fuel creates the potential for sustainable production of the analysed power plant and compliance with the current emission values of basic pollutants and new stricter limits, which will be binding in the EU from August 2021. The proposed solutions were analysed by Monte Carlo simulation. An estimate of the economic results achieved by the power... [more]

Biomass chemical looping gasification (CLG) is a novel gasification technology for hydrogen production, where the oxygen carrier (OC) transfers lattice oxygen to catalytically oxidize fuel into syngas. However, the OC is gradually reduced, showing different reaction activities in the CLG process. Fully understanding the CLG reaction mechanism of fuel molecules on perfect and reduced OC surfaces is necessary, for which the CLG of ethanol using Fe2O3 as the OC was introduced as the probe reaction to perform density functional theory calculations to reveal the decomposition mechanism of ethanol into the synthesis gas (including H2, CH4, ethylene, formaldehyde, acetaldehyde, and CO) on perfect and reduced Fe2O3(001) surfaces. When Fe2O3(001) is reduced to FeO0.375(001), the calculated barrier energy decreases and then increases again, suggesting that the reduction state around FeO(001) favors the catalytic decomposition of ethanol to produce hydrogen, which proves that the degree of reduct... [more]

The demand for clean energy is a key global issue requiring global ideas to be implemented through local action. This is particularly important in Poland’s energy transition, since the country produces energy mainly from conventional sources, i.e., coal, gas, and crude oil. Adverse climate change caused by high emissions of the economy based on the combustion of hydrocarbons as well as the growing public awareness have made it necessary to look for new environmentally friendly energy sources. The aim of the paper is to demonstrate that the use of alternative energy sources, biomass in particular, is compatible with sustainable development policy. Eight indicators for the EU-28 and for Poland were analysed in order to verify the progress in modifying the energy mix between 2010 and 2018 in the context of implementing Sustainable Development Goals (SDGs). The analysis showed that both in the EU-28 and in Poland, the aggregated indicator taking into account the positive and negative chang... [more]

This paper addresses the solar thermochemical conversion of biomass or waste feedstocks based on pyro-gasification for the clean production of high-value and energy-intensive fuels. The utilization of solar energy for supplying the required process heat is attractive to lower the dependence of gasification processes on conventional energy resources and to reduce emissions of CO2 and other pollutants for the production of high-value chemical synthetic fuels (syngas). Using concentrated solar energy to drive the endothermal reactions further allows producing more syngas with a higher gas quality, since it has not been contaminated by combustion products, while saving biomass resources. The solar-driven process is thus a sustainable and promising alternative route, enabling syngas yield enhancement and CO2 mitigation, thereby potentially outperforming the performance of conventional processes for syngas production. This review presents relevant research studies in the field and provides t... [more]

Hydrothermal pretreatment of biomass can improve fuel characteristics based on the decomposition properties of subcritical water. Thus, this study used a hydrothermal treatment to improve the fuel characteristics of empty fruit bunches (EFBs), which are generated as waste after palm oil extraction. The experimental reaction temperature was increased from 180 °C to 250 °C at an interval of 10 °C and the mass ratios between the dry sample and water content were set to 1:8 and 1:16 so that the sample was sufficiently immersed. Additionally, the material properties of EFB under hydrothermal treatment conditions were investigated using mass and energy yields, elemental analysis, proximate analysis, thermogravimetric analysis, derivative thermogravimetry, and Fourier transform infrared spectroscopy analysis of the reaction products. As the reaction temperature increased, the fixed carbon content and heating value increased because volatile matter, including oxygen, was removed first, which i... [more]

The continued growth and evolving lifestyles of the human population require the urgent development of sustainable production in all its aspects. Microalgae have the potential of the sustainable production of various commodities; however, the energetic requirements of algae cultivation still largely contribute to the overall negative balance of many operation plants. Here, we evaluate energetic efficiency of biomass and lipids production by Chlorella pyrenoidosa in multi-tubular, helical-tubular, and flat-panel airlift pilot scale photobioreactors, placed in an indoor environment of greenhouse laboratory in Central Europe. Our results show that the main energy consumption was related to the maintenance of constant light intensity in the flat-panel photobioreactor and the culture circulation in the helical-tubular photobioreactor. The specific power input ranged between 0.79 W L−1 in the multi-tubular photobioreactor and 6.8 W L−1 in the flat-panel photobioreactor. The construction of m... [more]

Formic acid is a liquid organic hydrogen carrier giving hydrogen on demand using catalysts. Metal complexes are known to be used as efficient catalysts for the hydrogen production from formic acid decomposition. Their performance could be better than those of supported catalysts with metal nanoparticles. However, difficulties to separate metal complexes from the reaction mixture limit their industrial applications. This problem can be resolved by supporting metal complexes on the surface of different supports, which may additionally provide some surface sites for the formic acid activation. The review analyzes the literature on the application of supported metal complexes in the hydrogen production from formic acid. It shows that the catalytic activity of some stable Ru and Ir supported metal complexes may exceed the activity of homogeneous metal complexes used for deposition. Non-noble metal-based complexes containing Fe demonstrated sufficiently high performance in the reaction; howe... [more]

In Thailand, Napier grass is expected to play an important role as an energy resource for future power generation. To accomplish this goal, numerous areas are required for Napier grass plantations. Before introducing crops, the land potential of the country and the impact of crops on the environment should be assessed. The soil and water assessment tool (SWAT) model is very useful in investigating crop impacts and land potential. Unfortunately, the crop growth parameters of Napier grass are yet to be identified and, thus, conducting effective analysis has not been possible. Accordingly, in this study, parameter calibration and SWAT model validation of Napier grass production in Thailand was carried out using datasets from eight sites with 93 samples. Parameter sensitivity analysis was performed prior to parameter calibration, the results of which suggest that the radiation use efficiency and potential harvested index are both highly sensitive. The crop growth parameters were calibrated... [more]

Energy-storage metabolites such as neutral lipids and carbohydrates are valuable compounds for liquid biofuel production. The aim of this work is to elucidate the main biological responses of two algae species known for their effective energy-rich compound accumulation in nitrogen limitation and day−night cycles: Nannochloropsis gaditana, a seawater species, and Parachlorella kessleri, a freshwater species. Lipid and carbohydrate production are investigated, as well as cell resistance to mechanical disruption for energy-rich compound release. Nitrogen-depleted N. gaditana showed only a low consumption of energy-storage molecules with a non-significant preference for neutral lipids (TAG) and carbohydrates in day−night cycles. However, it did accumulate significantly fewer carbohydrates than P. kessleri. Following this, the highest levels of productivity for N. gaditana in chemostat cultures at four levels of nitrogen limitation were found to be 3.4 and 2.2 × 10−3 kg/m2·d for carbohydrat... [more]

This study investigated the quantitative and qualitative attributes of liquid product and biochar obtained from pyrolysis of woody biomass (rubberwood sawdust (RWS)) and non-woody biomasses (oil palm trunk (OPT) and oil palm fronds (OPF)). The prepared biomass was pyrolyzed at temperatures of 500 °C, 550 °C, and 600 °C by using an agitated bed pyrolysis reactor, and then the yields and characteristics of liquid product and biochar were determined. The results showed that liquid product and biochar yields were in the respective ranges of 35.94−54.40% and 23.46−25.98% (wt.). Pyrolysis of RWS at 550 °C provided the highest liquid yield. The energy content of the water free liquid product was in the range 12.19−22.32 MJ/kg. The liquid product had a low pH and it mainly contained phenol groups as indicated by GC-MS. The biochars had high carbon contents (75.07−82.02%), while their oxygen contents were low (14.22−22%). The higher heating value (HHV) of biochar was in the range 26.42−29.33 MJ... [more]

Biomass residues are often considered as a resource if conveniently converted in fuel and alternative feedstock for chemical processes, and their conversion into valuable products may occur by different pathways. This work is focused on the thermochemical conversion at moderate temperature and in steam atmosphere, a mild process in comparison to hydrothermal liquefaction, followed by extraction of soluble products in a solvent. Such process has been already applied to various residues and here extended to the case of marc, the residual pomace from wine making, largely produced worldwide. A pressurized batch reactor was used for the quantitative determination of produced solid and liquid fractions, and their qualitative characterization was performed by instrumental analyses. The pressurized steam conversion of marc was effective, providing a yield in liquid fraction, upon extraction in solvent, up to 30% of the raw dried biomass. The use of polar and nonpolar solvent for the extraction... [more]

This study presents a combined cooling, heating, and power system powered by biogas, suitable for small scale communities in remote locations. To run such a system, in order to obtain the daily life essentials of electricity, hot water, and cooling, municipal waste can be considered as an option. Furthermore, the organic Rankine cycle part of the organic Rankine cycle powered vapor compression chiller can be used in times of need for additional electric production. The system comprises a medium temperature organic Rankine cycle utilizing M-xylene as its working fluid, and the cooling was covered by an Isobutane vapor compression cycle powered by an R245fa employing organic Rankine cycle. The system analyzed was designated to provide 250 kW of electricity. The energetic and exergetic analysis was performed, considering several system design parameters. The impact of the design parameters in the prime mover has a much greater effect on the whole system. The system proposed can deliver co... [more]