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18 pages, 3158 KiB

Open AccessArticle

A Sustainable Approach on Spruce Bark Waste Valorization through Hydrothermal Conversion

by Iuliana Bejenari, Gabriela Hristea, Constantin Cărăușu, Alice Mija and Irina Volf

Processes 2022, 10(1), 111; https://doi.org/10.3390/pr10010111 - 06 Jan 2022

Cited by 3 | Viewed by 1620

Abstract

In the context of sustainable use of resources, hydrothermal conversion of biomass has received increased consideration. As well, the hydrochar (the solid C-rich phase that occurs after the process) has caused great interest. In this work, spruce bark (Picea abies) wastes [...] Read more.

In the context of sustainable use of resources, hydrothermal conversion of biomass has received increased consideration. As well, the hydrochar (the solid C-rich phase that occurs after the process) has caused great interest. In this work, spruce bark (Picea abies) wastes were considered as feedstock and the influence of hydrothermal process parameters (temperature, reaction time, and biomass to water ratio) on the conversion degree has been studied. Using the response surface methodology and MiniTab software, the process parameters were set up and showed that temperature was the significant factor influencing the conversion, while residence time and the solid-to-liquid ratio had a low influence. Furthermore, the chemical (proximate and ultimate analysis), structural (Fourier-transform infrared spectroscopy, scanning electron microscopy) and thermal properties (thermogravimetric analysis) of feedstock and hydrochar were analyzed. Hydrochar obtained at 280 °C, 1 h processing time, and 1/5 solid-to-liquid ratio presented a hydrophobic character, numerous functional groups, a lower O and H content, and an improved C matter, as well as a good thermal stability. Alongside the structural features, these characteristics endorsed this waste-based product for applications other than those already known as a heat source. Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes)

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11 pages, 1518 KiB

Open AccessFeature PaperArticle

The Effect of Electromagnetic Microwave Radiation on Methane Fermentation of Selected Energy Crop Species

by Marcin Zieliński, Marcin Dębowski and Joanna Kazimierowicz

Processes 2022, 10(1), 45; https://doi.org/10.3390/pr10010045 - 27 Dec 2021

Cited by 6 | Viewed by 2023

Abstract

The aim of the present study was to determine how thermal stimulation via electromagnetic microwave radiation impacts the yields of biogas and methane produced by methane fermentation of five selected energy crop species in anaerobic reactors. The resultant performance was compared with that [...] Read more.

The aim of the present study was to determine how thermal stimulation via electromagnetic microwave radiation impacts the yields of biogas and methane produced by methane fermentation of five selected energy crop species in anaerobic reactors. The resultant performance was compared with that of reactors with conventional temperature control. The highest biogas production capacity was achieved for maize silage and Virginia mallow silage (i.e., 680 ± 28 dm³_N/kg_VS and 506 ± 16 dm³_N/kg_VS, respectively). Microwave radiation as a method of heating anaerobic reactors provided a statistically-significantly boost in methane production from maize silage (18% increase). Biomethane production from maize silage rose from 361 ± 12 dm³_N/kg_VS to 426 ± 14 dm³_N/kg_VS. In the other experimental variants, the differences between methane concentrations in the biogas were non-significant. Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes)

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9 pages, 1658 KiB

Open AccessArticle

Performance of a Gasifier Reactor Prototype without a Blower Using Palm Oil Waste

by Arief Suardi Nur Chairat, Vendy Antono, Prayudi Prayudi, Roswati Nurhasanah and Hakimul Batih

Processes 2021, 9(11), 2094; https://doi.org/10.3390/pr9112094 - 22 Nov 2021

Viewed by 1850

Abstract

The usage of palm oil empty fruit bunches (EFBs) in the gasification process adds value to the empty bunches as a renewable energy source. In this study, we design and manufacture a new updraft type of gasifier reactor without a blower so that [...] Read more.

The usage of palm oil empty fruit bunches (EFBs) in the gasification process adds value to the empty bunches as a renewable energy source. In this study, we design and manufacture a new updraft type of gasifier reactor without a blower so that it does not require electric power in its operation, but uses power from engine suction. Our test results compare the use of biomass waste in conjunction with diesel fuel to run a diesel power plant for 20 min at a load of 10,000 W: diesel with coconut shell charcoal (350 mL), diesel with acacia wood charcoal (380 mL), and diesel with EFB charcoal (400 mL). The test shows that the highest efficient and the most optimal biomass in the gasification process is coconut shell charcoal, because coconut shell charcoal has a dense structure and, at the time of the experiment, the coconut shell charcoal was filled 15 cm below the gas outlet pipe hole. From the standpoint of the economic value of the gasifier reactor that is proposed in this study, the result with the lowest cost is that of diesel with EFB charcoal, because, in this experiment, EFBs were the biomass that was not purchased. The additional use of empty fruit bunches of charcoal is able to save 50% diesel usage. Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes)

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21 pages, 4586 KiB

Open AccessFeature PaperArticle

Biogas Upgrading by Pressure Swing Adsorption with Design of Experiments

by Yi-Fang Chen, Po-Wei Lin, Wen-Hua Chen, Fong-Yu Yen, Hong-Sung Yang and Cheng-Tung Chou

Processes 2021, 9(8), 1325; https://doi.org/10.3390/pr9081325 - 29 Jul 2021

Cited by 10 | Viewed by 3806

Abstract

Global warming is predominantly caused by methane (CH₄) and carbon dioxide (CO₂) emissions. CH₄ is estimated to have a global warming potential (GWP) of 28–36 over 100 years. Its impact on the greenhouse effect cannot be overstated. In [...] Read more.

Global warming is predominantly caused by methane (CH₄) and carbon dioxide (CO₂) emissions. CH₄ is estimated to have a global warming potential (GWP) of 28–36 over 100 years. Its impact on the greenhouse effect cannot be overstated. In this report, a dual-bed eight-step pressure swing adsorption (PSA) process was used to simulate the separation of high-purity CH₄ as renewable energy from biogas (36% CO₂, 64% CH₄, and 100 ppm H₂S) in order to meet Taiwan’s natural gas pipeline standards (>95% CH₄ with H₂S content < 4 ppm). Three selectivity parameters were used to compare the performance of the adsorbents. In the simulation program, the extended Langmuir–Freundlich isotherm was used for calculating the equilibrium adsorption capacity, and the linear driving force model was used to describe the gas adsorption kinetics. After the basic case simulation and design of experiments (DOE) for the laboratory-scale PSA, we obtained a top product CH₄ purity of 99.28% with 91.44% recovery and 0.015 ppm H₂S purity, and the mechanical energy consumption was estimated to be 0.86 GJ/ton-CH₄. Lastly, a full scale PSA process simulation was conducted for the commercial applications with 500 m³/h biogas feed, and the final CH₄ product with a purity of 96.1%, a recovery of 91.39%, and a H₂S content of 1.14 ppm could be obtained, which can meet the standards of natural gas pipelines in Taiwan. Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes)

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16 pages, 1672 KiB

Open AccessFeature PaperArticle

Thermophilic Anaerobic Digestion of Second Cheese Whey: Microbial Community Response to H₂ Addition in a Partially Immobilized Anaerobic Hybrid Reactor

by Giuseppe Lembo, Silvia Rosa, Valentina Mazzurco Miritana, Antonella Marone, Giulia Massini, Massimiliano Fenice and Antonella Signorini

Processes 2021, 9(1), 43; https://doi.org/10.3390/pr9010043 - 28 Dec 2020

Cited by 14 | Viewed by 2420

Abstract

In this study, we investigated thermophilic (55 °C) anaerobic digestion (AD) performance and microbial community structure, before and after hydrogen addition, in a novel hybrid gas-stirred tank reactor (GSTR) implemented with a partial immobilization of the microbial community and fed with second cheese [...] Read more.

In this study, we investigated thermophilic (55 °C) anaerobic digestion (AD) performance and microbial community structure, before and after hydrogen addition, in a novel hybrid gas-stirred tank reactor (GSTR) implemented with a partial immobilization of the microbial community and fed with second cheese whey (SCW). The results showed that H₂ addition led to a 25% increase in the methane production rate and to a decrease of 13% in the CH₄ concentration as compared with the control. The recovery of methane content (56%) was reached by decreasing the H₂ flow rate. The microbial community investigations were performed on effluent (EF) and on interstitial matrix (IM) inside the immobilized area. Before H₂ addition, the Anaerobaculaceae (42%) and Lachnospiraceae (27%) families dominated among bacteria in the effluent, and the Thermodesulfobiaceae (32%) and Lachnospiraceae (30%) families dominated in the interstitial matrix. After H₂ addition, microbial abundance showed an increase in the bacteria and archaea communities in the interstitial matrix. The Thermodesulfobiaceae family (29%)remained dominant in the interstitial matrix, suggesting its crucial role in the immobilized community and the SHA-31 family was enriched in both the effluent (36%) and the interstitial matrix (15%). The predominance of archaea Methanothermobacter thermoautrophicus indicated that CH₄ was produced almost exclusively by the hydrogenotrophic pathway. Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes)

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18 pages, 15526 KiB

Open AccessFeature PaperArticle

Experimental and Numerical Analysis of a Low Environmental Impact Pyro-Gasification System for the Energetic Valorization of Waste through a Biomass Steam Power Plant

by Alfredo Gimelli, Massimiliano Muccillo, Raniero Sannino, Giacobbe Braccio, Vincenzo Capone, Giacinto Cornacchia, Matteo Manganiello, Carmine Mongiello and Vinod Kumar Sharma

Processes 2021, 9(1), 35; https://doi.org/10.3390/pr9010035 - 25 Dec 2020

Viewed by 2372

Abstract

This paper addresses the study of a pyro-gasification plant designed, built, and operated to recover inert metals from different types of solid waste. Experimental tests were carried out using pulper as the solid waste. However, while a reliable composition analysis of the produced [...] Read more.

This paper addresses the study of a pyro-gasification plant designed, built, and operated to recover inert metals from different types of solid waste. Experimental tests were carried out using pulper as the solid waste. However, while a reliable composition analysis of the produced syngas was carried out, a precise composition evaluation of the pulper used during the experimental activities was not performed and the related data were characterized by unacceptable uncertainty. Therefore, with the aim of reliably characterizing the plant operation, a thermochemical model of the gasification process was setup to simulate the equilibrium operation of the plant and a vector optimization methodology was used to calibrate the numerical model. Then, a decision-making problem was solved to identify the most suitable optimal solution between those belonging to the Pareto optimal front, thus obtaining reliable composition data for the adopted pulper waste. In particular, four different identification criteria were applied for the selection of small subset of solutions over the 3138 dominant solutions found. Among them, the solution (i.e., set of calibration parameters) that minimizes the experimental-numerical difference between the lower heating value of the produced syngas seemed to provide the most reliable approximation of the real plant operation. Finally, a possible plant configuration is proposed for the energetic valorization of the pulper waste and its overall conversion process efficiency is estimated. Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes)

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15 pages, 2750 KiB

Open AccessArticle

Arundo donax Refining to Second Generation Bioethanol and Furfural

by Isabella De Bari, Federico Liuzzi, Alfredo Ambrico and Mario Trupo

Processes 2020, 8(12), 1591; https://doi.org/10.3390/pr8121591 - 03 Dec 2020

Cited by 14 | Viewed by 2048

Abstract

Biomass-derived sugars are platform molecules that can be converted into a variety of final products. Non-food, lignocellulosic feedstocks, such as agroforest residues and low inputs, high yield crops, are attractive bioresources for the production of second-generation sugars. Biorefining schemes based on the use [...] Read more.

Biomass-derived sugars are platform molecules that can be converted into a variety of final products. Non-food, lignocellulosic feedstocks, such as agroforest residues and low inputs, high yield crops, are attractive bioresources for the production of second-generation sugars. Biorefining schemes based on the use of versatile technologies that operate at mild conditions contribute to the sustainability of the bio-based products. The present work describes the conversion of giant reed (Arundo donax), a non-food crop, to ethanol and furfural (FA). A sulphuric-acid-catalyzed steam explosion was used for the biomass pretreatment and fractionation. A hybrid process was optimized for the hydrolysis and fermentation (HSSF) of C6 sugars at high gravity conditions consisting of a biomass pre-liquefaction followed by simultaneous saccharification and fermentation with a step-wise temperature program and multiple inoculations. Hemicellulose derived xylose was dehydrated to furfural on the solid acid catalyst in biphasic media irradiated by microwave energy. The results indicate that the optimized HSSF process produced ethanol titers in the range 43–51 g/L depending on the enzymatic dosage, about 13–21 g/L higher than unoptimized conditions. An optimal liquefaction time before saccharification and fermentation tests (SSF) was 10 h by using 34 filter paper unit (FPU)/g glucan of Cellic^® CTec3. C5 streams yielded 33.5% FA of the theoretical value after 10 min of microwave heating at 157 °C and a catalyst concentration of 14 meq per g of xylose. Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes)

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18 pages, 1400 KiB

Open AccessFeature PaperArticle

From Cardoon Lignocellulosic Biomass to Bio-1,4 Butanediol: An Integrated Biorefinery Model

by Isabella De Bari, Aristide Giuliano, Maria Teresa Petrone, Giovanni Stoppiello, Vittoria Fatta, Cecilia Giardi, Francesco Razza and Alessandra Novelli

Processes 2020, 8(12), 1585; https://doi.org/10.3390/pr8121585 - 01 Dec 2020

Cited by 29 | Viewed by 4532

Abstract

Biorefineries are novel, productive models that are aimed at producing biobased alternatives to many fossil-based products. Biomass supply and overall energy consumptions are important issues determining the overall biorefinery sustainability. Low-profit lands appear to be a potential option for the sustainable production of [...] Read more.

Biorefineries are novel, productive models that are aimed at producing biobased alternatives to many fossil-based products. Biomass supply and overall energy consumptions are important issues determining the overall biorefinery sustainability. Low-profit lands appear to be a potential option for the sustainable production of raw materials without competition with the food chain. Cardoon particularly matches these characteristics, thanks to the rapid growth and the economy of the cultivation and harvesting steps. An integrated biorefinery processing 60 kton/y cardoon lignocellulosic biomass for the production of 1,4-butanediol (bio-BDO) is presented and discussed in this work. After designing the biorefinery flowsheet, the mass and energy balances were calculated. The results indicated that the energy recovery system has been designed to almost completely cover the entire energy requirement of the BDO production process. Despite the lower supply of electricity, the energy recovery system can cover around 78% of the total electricity demand. Instead, the thermal energy recovery system was able to satisfy the overall demand of the sugar production process entirely, while BDO purification columns require high-pressure steam. The thermal energy recovery system can cover around 83% of the total thermal demand. Finally, a cradle-to-gate simplified environmental assessment was conducted in order to evaluate the environmental impact of the process in terms of carbon footprint. The carbon footprint value calculated for the entire production process of BDO was 2.82 kg_CO2eq/kg_BDO. The cultivation phase accounted for 1.94 kg_CO2eq/kg_BDO, the transport had very little impact, only for 0.067 kg_CO2eq/kg_BDO, while the biorefinery phase contributes for 0.813 kg_CO2eq/kg_BDO. Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes)

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9 pages, 1220 KiB

Open AccessFeature PaperArticle

Effect of Harvesting Age and Size Reduction in the Performance of Anaerobic Digestion of Pennisetum Grass

by Carlos Alexander Pizarro-Loaiza, Patricia Torres-Lozada, Josep Illa, Jordi Palatsi and August Bonmatí

Processes 2020, 8(11), 1414; https://doi.org/10.3390/pr8111414 - 06 Nov 2020

Cited by 6 | Viewed by 2134

Abstract

In the rural zones of Latin American and Caribbean developing countries, the poorest households rely on traditional fuels such as firewood to meet their daily cooking needs. Many of those countries are located near the equator, where they have a tropical climate and [...] Read more.

In the rural zones of Latin American and Caribbean developing countries, the poorest households rely on traditional fuels such as firewood to meet their daily cooking needs. Many of those countries are located near the equator, where they have a tropical climate and grass is one of the most common biomass crops. The aim of this study was to evaluate the effect of harvesting age (30, 44, and 57 days) in the performance of anaerobic digestion of King Grass (Pennisetum purpureum cv. King Grass) grown under tropical climate conditions. Three reduction methods of crop size were also compared. Results showed that 44-day harvesting age presented the greater specific methane yield (347.8 mLCH₄ g⁻¹VS) and area-specific methane yield (9773 m³CH₄ ha⁻¹ y⁻¹). The machine chopped method (1–3 cm for stems and 1–10 cm for leaves) was the reduction method that maximized the methane production. From those results, the calculated area required for grass cultivation to provide the cooking energy to a typical family in the Colombian rural zones is 154 m². Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes)

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27 pages, 18911 KiB

Open AccessFeature PaperArticle

CFD Hydrodynamics Investigations for Optimum Biomass Gasifier Design

by Emanuele Fanelli

Processes 2020, 8(10), 1323; https://doi.org/10.3390/pr8101323 - 21 Oct 2020

Cited by 3 | Viewed by 2902

Abstract

Biomass gasification is nowadays considered a viable option for clean energy production. Furthermore, still more efforts need to be spent to make this technology fully available at commercial scale. Drawbacks that greatly limit the full-time plant availability—and so its economically feasibility—mainly concerns syngas [...] Read more.

Biomass gasification is nowadays considered a viable option for clean energy production. Furthermore, still more efforts need to be spent to make this technology fully available at commercial scale. Drawbacks that greatly limit the full-time plant availability—and so its economically feasibility—mainly concerns syngas purification by contaminants such as tars. Different technological approaches were investigated over last two decades with the aim to increase both the plant availability and the overall efficiency by keeping, at the same time, CAPEX and OPEX low. Among technologies, fluidized beds are surely the most promising architectures for power production at thermal scale above 1 MW_th. Gasifier can be surely considered the key component of the whole power plant and its proper design, the main engineering effort. This process involves different engineering aspects: thermo-structural, heat, and mass transfer, and chemical and fluid-dynamic concerns being the most important. In this study, with the aim to reach an optimal reaction chamber design, the hydrodynamics of a bubbling fluidized bed reactor was investigated by using a CFD approach. A Eulerian–Eulerian multiphase model, supported by experimental data, was implemented to describe the interactions between the solid and fluid phases inside the reactor while a discrete dense phase model (DDPM) model was considered to investigate momentum exchange among continuous phases and solid particles simulating char. Different process parameters, such as the bed recirculation rate and the particles circulation time inside the bed, were at least analyzed to characterize the hydrodynamics of the reactor. Results indicate that the recirculation time of bed material is in the order of 6–7 s at bench scale and, respectively, of 15–20 s at full scale. Information about solid particles inside the bed that should be used to avoid elutriation and agglomeration phenomenon, suggest that the dimension of the mother fuel particles should not exceed the value of 5–10 mm. Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes)

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0 pages, 2976 KiB

Open AccessArticle

Life Cycle Assessment Analysis of Alfalfa and Corn for Biogas Production in a Farm Case Study

by Fabiola Filippa, Francesco Panara, Daniela Leonardi, Livia Arcioni and Ornella Calderini

Processes 2020, 8(10), 1285; https://doi.org/10.3390/pr8101285 - 14 Oct 2020

Cited by 11 | Viewed by 3001

Abstract

In the last years the greenhouse effect has been significantly intensified due to human activities, generating large additional amounts of Greenhouse gases (GHG). The fossil fuels are the main causes of that. Consequently, the attention on the composition of the national fuel mix [...] Read more.

In the last years the greenhouse effect has been significantly intensified due to human activities, generating large additional amounts of Greenhouse gases (GHG). The fossil fuels are the main causes of that. Consequently, the attention on the composition of the national fuel mix has significantly grown, and the renewables are becoming a more significant component. In this context, biomass is one of the most important sources of renewable energy with a great potential for the production of energy. The study has evaluated, through an LCA (Life Cycle Assessment) study, the attitude of alfalfa (Medicago sativa) as “no food” biomass alternative to maize silage (corn), in the production of biogas from anaerobic digestion. Considering the same functional unit (1 m³ of biogas from anaerobic digestion) and the same time horizon, alfalfa environmental impact was found to be much comparable to that of corn because it has an impact of about 15% higher than corn considering the total score from different categories and an impact of 5% higher of corn considering only greenhouse gases. Therefore, the analysis shows a similar environmental load in the use of alfalfa biomass in energy production compared to maize. Corn in fact, despite a better yield per hectare and yield of biogas, requires a greater amount of energy inputs to produce 1m³ of biogas, while alfalfa, which requires less energy inputs in its life cycle, has a lower performance in terms of yield. The results show the possibility to alternate the two crops for energy production from an environmental perspective. Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes)

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16 pages, 3137 KiB

Open AccessArticle

Comparing Low-Temperature Hydrothermal Pretreatments through Convective Heating versus Microwave Heating for Napier Grass Digestion

by Kanyarat Saritpongteeraka, Jutawan Kaewsung, Boonya Charnnok and Sumate Chaiprapat

Processes 2020, 8(10), 1221; https://doi.org/10.3390/pr8101221 - 30 Sep 2020

Cited by 10 | Viewed by 2264

Abstract

This study investigates the effects of convective hydrothermal pretreatment (CHTP) compared to microwave pretreatment (MWP) on the anaerobic digestion of hybrid Napier grass for biomethane production. For rapid estimation of methane yield (Y_CH4), enzymatic hydrolyzability (EH), whose test lasts only 2 [...] Read more.

This study investigates the effects of convective hydrothermal pretreatment (CHTP) compared to microwave pretreatment (MWP) on the anaerobic digestion of hybrid Napier grass for biomethane production. For rapid estimation of methane yield (Y_CH4), enzymatic hydrolyzability (EH), whose test lasts only 2 days was used as a surrogate parameter instead of the biochemical methane potential (BMP) assay that normally takes 45–60 days. The relationship between EH and BMP was successfully modeled with satisfactory accuracy (R² = 0.9810). From CHTP results, quadratic regression characterised by p < 0.0001 and R² = 0.8364 shows that Y_CH₄ increase was clearly sensitive to detention time at all CHTP temperatures. The maximal Y_CH₄ achieved of 301.5 ± 3.0 mL CH₄/gVS_add was 53.2% higher than the control. Then, MWP was employed at various power levels and microwave exposure times. Changes in lignocellulosic structure by Fourier-transform infrared spectroscopy (FTIR) and energy balance demonstrate that MWP caused more damage to plant cells, which proved more effective than CHTP. In the best conditions, approximately 50% of energy was needed for MWP to achieve the equivalent improvement in Y_CH4. However, CHTP is a more suitable option since waste heat, i.e., from a biogas CHP (combined heat and power) unit, could be used, as opposed to the electricity required for MWP. Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes)

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16 pages, 4599 KiB

Open AccessArticle

SuperPro Designer^®, User-Oriented Software Used for Analyzing the Techno-Economic Feasibility of Electrical Energy Generation from Sugarcane Vinasse in Colombia

by Licelly Canizales, Fredy Rojas, Carlos A. Pizarro, Nelson. H. Caicedo-Ortega and M. F. Villegas-Torres

Processes 2020, 8(9), 1180; https://doi.org/10.3390/pr8091180 - 18 Sep 2020

Cited by 18 | Viewed by 9603

Abstract

SuperPro Designer^® is a process simulator software used for analyzing the techno-economic feasibility of large-scale bioprocesses. Its predetermined built-in features allow for easy implementation by non-experts, but a lack of examples limits its appropriation. This study aims to validate the implementation of [...] Read more.

SuperPro Designer^® is a process simulator software used for analyzing the techno-economic feasibility of large-scale bioprocesses. Its predetermined built-in features allow for easy implementation by non-experts, but a lack of examples limits its appropriation. This study aims to validate the implementation of SuperPro Designer^® by non-experts for the techno-economic analysis of anaerobic digestion in Colombia, using vinasse as feedstock. These results demonstrate the financial feasibility of such a process when a processing flow rate of 25 m³/h is ensured. Additionally, this study validates the manageability of the tool for assessing the economic feasibility of a technology, a key practice during technology development regardless of the area of expertise. Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes)

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11 pages, 2069 KiB

Open AccessArticle

Upgrading of Biogas to Methane Based on Adsorption

by Jun Liu, Qiang Chen and Peng Qi

Processes 2020, 8(8), 941; https://doi.org/10.3390/pr8080941 - 05 Aug 2020

Cited by 9 | Viewed by 4361

Abstract

Upgrading raw biogas to methane (CH₄) is a vital prerequisite for the utilization of biogas as a vehicle fuel or the similar field as well. In this work, biogas yield from the anaerobic fermentation of food waste containing methane (CH₄ [...] Read more.

Upgrading raw biogas to methane (CH₄) is a vital prerequisite for the utilization of biogas as a vehicle fuel or the similar field as well. In this work, biogas yield from the anaerobic fermentation of food waste containing methane (CH₄, 60.4%), carbon dioxide (CO₂, 29.1%), hydrogen sulfide (H₂S, 1.5%), nitrogen (N₂, 7.35%) and oxygen (O₂, 1.6%) was upgraded by dynamic adsorption. The hydrogen sulfide was removed from the biogas in advance by iron oxide (Fe₂O₃) because of its corrosion of the equipment. Commercial 13X zeolite and carbon molecular sieve (CMS) were used to remove the other impurity gases from wet or dry biogas. It was found that neither 13X zeolite nor CMS could effectively remove each of the impurities in the wet biogas for the effect of water vapor. However, 13X zeolite could effectively remove CO₂ after the biogas was dried with silica and showed a CO₂ adsorption capacity of 78 mg/g at the condition of 0.2 MPa and 25 °C. Additionally, 13X zeolite almost did not adsorb nitrogen (N₂), so the CH₄ was merely boosted to ac. 91% after the desulfurated dry biogas passed through 13X zeolite, nitrogen remaining in the biogas. CMS would exhibit superior N₂ adsorption capacity and low CO₂ adsorption capacity if some N₂ was present in biogas, so CMS was able to remove all the nitrogen and fractional carbon dioxide from the desulfurated dry biogas in a period of time. Finally, when the desulfurated dry biogas passed through CMS and 13X zeolite in turn, the N₂ and CO₂ were sequentially removed, and then followed the high purity CH₄ (≥96%). Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes)

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Review

Jump to: Research

38 pages, 3489 KiB

Open AccessFeature PaperReview

Syngas Derived from Lignocellulosic Biomass Gasification as an Alternative Resource for Innovative Bioprocesses

by Cosetta Ciliberti, Antonino Biundo, Roberto Albergo, Gennaro Agrimi, Giacobbe Braccio, Isabella de Bari and Isabella Pisano

Processes 2020, 8(12), 1567; https://doi.org/10.3390/pr8121567 - 28 Nov 2020

Cited by 44 | Viewed by 7574

Abstract

A hybrid system based on lignocellulosic biomass gasification and syngas fermentation represents a second-generation biorefinery approach that is currently in the development phase. Lignocellulosic biomass can be gasified to produce syngas, which is a gas mixture consisting mainly of H₂, CO, [...] Read more.

A hybrid system based on lignocellulosic biomass gasification and syngas fermentation represents a second-generation biorefinery approach that is currently in the development phase. Lignocellulosic biomass can be gasified to produce syngas, which is a gas mixture consisting mainly of H₂, CO, and CO₂. The major challenge of biomass gasification is the syngas’s final quality. Consequently, the development of effective syngas clean-up technologies has gained increased interest in recent years. Furthermore, the bioconversion of syngas components has been intensively studied using acetogenic bacteria and their Wood–Ljungdahl pathway to produce, among others, acetate, ethanol, butyrate, butanol, caproate, hexanol, 2,3-butanediol, and lactate. Nowadays, syngas fermentation appears to be a promising alternative for producing commodity chemicals in comparison to fossil-based processes. Research studies on syngas fermentation have been focused on process design and optimization, investigating the medium composition, operating parameters, and bioreactor design. Moreover, metabolic engineering efforts have been made to develop genetically modified strains with improved production. In 2018, for the first time, a syngas fermentation pilot plant from biomass gasification was built by LanzaTech Inc. in cooperation with Aemetis, Inc. Future research will focus on coupling syngas fermentation with additional bioprocesses and/or on identifying new non-acetogenic microorganisms to produce high-value chemicals beyond acetate and ethanol. Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes)

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