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Zbair M, Limousy L, Drané M, Richard C, Juge M, Aemig Q, Trably E, Escudié R, Peyrelasse C, Bennici S. Integration of Digestate-Derived Biochar into the Anaerobic Digestion Process through Circular Economic and Environmental Approaches-A Review. MATERIALS (BASEL, SWITZERLAND) 2024; 17:3527. [PMID: 39063819 PMCID: PMC11278828 DOI: 10.3390/ma17143527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Revised: 07/10/2024] [Accepted: 07/11/2024] [Indexed: 07/28/2024]
Abstract
The growing energy consumption and the need for a circular economy have driven considerable interest in the anaerobic digestion (AD) of organic waste, offering potential solutions through biogas and digestate production. AD processes not only have the capability to reduce greenhouse gas emissions but also contribute to the production of renewable methane. This comprehensive review aims to consolidate prior research on AD involving different feedstocks. The principles of AD are explored and discussed, including both chemical and biological pathways and the microorganisms involved at each stage. Additionally, key variables influencing system performance, such as temperature, pH, and C/N ratio are also discussed. Various pretreatment strategies applied to enhance biogas generation from organic waste in AD are also reviewed. Furthermore, this review examines the conversion of generated digestate into biochar through pyrolysis and its utilization to improve AD performance. The addition of biochar has demonstrated its efficacy in enhancing metabolic processes, microorganisms (activity and community), and buffering capacity, facilitating Direct Interspecies Electron Transfer (DIET), and boosting CH4 production. Biochar also exhibits the ability to capture undesirable components, including CO2, H2S, NH3, and siloxanes. The integration of digestate-derived biochar into the circular economy framework emerges as a vital role in closing the material flow loop. Additionally, the review discusses the environmental benefits derived from coupling AD with pyrolysis processes, drawing on life cycle assessment investigations. Techno-economic assessment (TEA) studies of the integrated processes are also discussed, with an acknowledgment of the need for further TEA to validate the viability of integrating the biochar industry. Furthermore, this survey examines the techno-economic and environmental impacts of biochar production itself and its potential application in AD for biogas generation, aiming to establish a more cost-effective and sustainable integrated system.
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Affiliation(s)
- Mohamed Zbair
- Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace, CNRS, IS2M UMR 7361, 68100 Mulhouse, France; (M.Z.); (M.D.); (S.B.)
- Université de Strasbourg, 67000 Strasbourg, France
| | - Lionel Limousy
- Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace, CNRS, IS2M UMR 7361, 68100 Mulhouse, France; (M.Z.); (M.D.); (S.B.)
- Université de Strasbourg, 67000 Strasbourg, France
| | - Méghane Drané
- Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace, CNRS, IS2M UMR 7361, 68100 Mulhouse, France; (M.Z.); (M.D.); (S.B.)
- Université de Strasbourg, 67000 Strasbourg, France
| | - Charlotte Richard
- ENGIE, Lab CRIGEN, 4 Rue Joséphine Baker, 93240 Stains, France; (C.R.); (M.J.); (Q.A.)
| | - Marine Juge
- ENGIE, Lab CRIGEN, 4 Rue Joséphine Baker, 93240 Stains, France; (C.R.); (M.J.); (Q.A.)
| | - Quentin Aemig
- ENGIE, Lab CRIGEN, 4 Rue Joséphine Baker, 93240 Stains, France; (C.R.); (M.J.); (Q.A.)
| | - Eric Trably
- INRAE, University of Montpellier, LBE, 102 Av. des Etangs, 11100 Narbonne, France; (E.T.); (R.E.)
| | - Renaud Escudié
- INRAE, University of Montpellier, LBE, 102 Av. des Etangs, 11100 Narbonne, France; (E.T.); (R.E.)
| | | | - Simona Bennici
- Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace, CNRS, IS2M UMR 7361, 68100 Mulhouse, France; (M.Z.); (M.D.); (S.B.)
- Université de Strasbourg, 67000 Strasbourg, France
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Rücker C, Grabitz E, Kümmerer K. Are Si-C bonds cleaved by microorganisms? A critical review on biodegradation of methylsiloxanes. CHEMOSPHERE 2023; 321:137858. [PMID: 36642148 DOI: 10.1016/j.chemosphere.2023.137858] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/22/2022] [Accepted: 01/11/2023] [Indexed: 06/17/2023]
Abstract
Methylsiloxanes, compounds that contain H3C-Si-O subunits in their molecular structure, are emerging ubiquitous pollutants now detected in many environmental compartments. These compounds and generally Si-C bonds do not occur in living nature, but are industrially produced worldwide in millions of tons per annum and are widely used, resulting in their release to the environment. It is an open question whether or to what extent microorganisms are able to decompose these compounds. The presence of methylsiloxanes in many biogases adds to the economic relevance of this question. We here review and critically discuss, for the first time, the evidence obtained for and against degradation of methylsiloxanes by microorganisms, and in particular for microbial cleavage of Si-CH3 bonds. As a result, no convincing demonstration of Si-C cleavage by native environmental microorganisms has been found.
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Affiliation(s)
- Christoph Rücker
- Institute for Sustainable Chemistry, Leuphana University Lüneburg, Universitätsallee 1, D-21335, Lüneburg, Germany.
| | - Elisa Grabitz
- Institute for Sustainable Chemistry, Leuphana University Lüneburg, Universitätsallee 1, D-21335, Lüneburg, Germany
| | - Klaus Kümmerer
- Institute for Sustainable Chemistry, Leuphana University Lüneburg, Universitätsallee 1, D-21335, Lüneburg, Germany
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3
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Galdi SM, Szczuka A, Shin C, Mitch WA, Luthy RG. Dissolved Methane Recovery and Trace Contaminant Fate Following Mainstream Anaerobic Treatment of Municipal Wastewater. ACS ES&T ENGINEERING 2023; 3:121-130. [PMID: 36660091 PMCID: PMC9841518 DOI: 10.1021/acsestengg.2c00256] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 06/01/2023]
Abstract
Anaerobic treatment of municipal wastewater with the staged anaerobic fluidized bed membrane bioreactor (SAF-MBR) shows promise to transform secondary wastewater treatment into an energy-positive process. However, the dissolved methane in SAF-MBR effluent needs to be recovered to reach net energy positive. To recover this methane for energy generation, an air stripping system was constructed downstream of a pilot-scale SAF-MBR facility and operated for over 80 days. The process removed 98% of effluent dissolved methane, and with the addition of intermittent disinfection recovered an average of 90% of the dissolved methane. The exit gas from air-stripping comprised 1.5-2.5% methane and could be utilized by blending with biogas produced from primary solids digestion and the SAF-MBR in an on-site combustion process. The direct energy costs for air stripping methane are <1% of the energy recoverable from the dissolved methane, not accounting for siloxane or sulfide scrubbing. Only siloxanes were observed at levels impacting combustion in this study, with 1.6 mg Si/m3 present in the blended biogas and air stripping mixture. The fate of a subset of trace organic contaminants was examined across the air stripping unit to check for aerobic degradation by methanotrophs or other opportunistic aerobes. Only 1,4-dioxane and benzotriazole showed statistically significant removal among 17 compounds screened, with 0.53 ± 0.13 and 0.34 ± 0.15 fraction removal, respectively. Our results indicate that air stripping is an energy efficient and robust technology for dissolved methane removal and onsite utilization for heat and electricity generation from anaerobic treatment of municipal wastewater.
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Affiliation(s)
- Stephen M. Galdi
- Stanford
University, Stanford, California94305, United States
- NSF
Engineering Research Center for Re-inventing the Nation’s Urban
Water Infrastructure (ReNUWIt), https://www.renuwit.org/contact/
| | - Aleksandra Szczuka
- NSF
Engineering Research Center for Re-inventing the Nation’s Urban
Water Infrastructure (ReNUWIt), https://www.renuwit.org/contact/
- University
of Michigan, 1351 Beal Avenue, Ann Arbor, Michigan48019, United
States
| | - Chungheon Shin
- Stanford
University, Stanford, California94305, United States
- NSF
Engineering Research Center for Re-inventing the Nation’s Urban
Water Infrastructure (ReNUWIt), https://www.renuwit.org/contact/
| | - William A. Mitch
- Civil
and Environmental Engineering, Stanford
University, Stanford, California94305, United States
- NSF
Engineering Research Center for Re-inventing the Nation’s Urban
Water Infrastructure (ReNUWIt), https://www.renuwit.org/contact/
| | - Richard G. Luthy
- Civil
and Environmental Engineering, Stanford
University, Stanford, California94305, United States
- NSF
Engineering Research Center for Re-inventing the Nation’s Urban
Water Infrastructure (ReNUWIt), https://www.renuwit.org/contact/
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Saeid Hosseini S, Azadi Tabar M, F. J. Vankelecom I, F. M. Denayer J. Progress in High Performance Membrane Materials and Processes for Biogas Production, Upgrading and Conversion. Sep Purif Technol 2023. [DOI: 10.1016/j.seppur.2023.123139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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5
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Alves CMAC, Abreu FOMS, Araújo RS, Oliveira MLM. Recent advances in siloxanes removal from biogas and their efficiency: a short review. CHEMICAL PAPERS 2022. [DOI: 10.1007/s11696-022-02460-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Zheng Y, Hou X, Lv S, Ma Z, Ma X. Efficient Removal of Siloxane from Biogas by Using β-Cyclodextrin-Modified Reduced Graphene Oxide Aerogels. NANOMATERIALS 2022; 12:nano12152643. [PMID: 35957075 PMCID: PMC9370590 DOI: 10.3390/nano12152643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/25/2022] [Accepted: 07/29/2022] [Indexed: 12/02/2022]
Abstract
In this study, β-cyclodextrin-modified reduced graphene oxide aerogels (β-CD-rGOAs) were synthesized via a one-step hydrothermal method and were used to remove hexamethyldisiloxane (L2) from biogas. The β-CD-rGOAs were characterized by the Brunner–Emmet–Teller technique, using Fourier-transform infrared spectroscopy, Raman spectrometry, scanning electron microscopy (SEM), contact angle measurements, and X-ray diffraction. The results of the characterizations indicate that β-CD was grafted onto the surface of rGOAs as a cross-linking modifier. The β-CD-rGOA had a three-dimensional, cross-linked porous structure. The maximum breakthrough adsorption capacity of L2 on β-CD-rGOA at 273 K was 111.8 mg g−1. A low inlet concentration and bed temperature facilitated the adsorption of L2. Moreover, the β-CD-rGOA was regenerated by annealing at 80 °C, which renders this a promising material for removing L2 from biogas.
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Affiliation(s)
- Yanhui Zheng
- Hebei Key Laboratory of Inorganic Nano-Materilas, College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024, China; (Y.Z.); (X.H.); (S.L.)
- Department of Preshool and Art Education, Shijiazhuang Vocational College of Finance & Economics, Shijiazhuang 050061, China
| | - Xifeng Hou
- Hebei Key Laboratory of Inorganic Nano-Materilas, College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024, China; (Y.Z.); (X.H.); (S.L.)
| | - Siqi Lv
- Hebei Key Laboratory of Inorganic Nano-Materilas, College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024, China; (Y.Z.); (X.H.); (S.L.)
| | - Zichuan Ma
- Hebei Key Laboratory of Inorganic Nano-Materilas, College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024, China; (Y.Z.); (X.H.); (S.L.)
- Correspondence: (Z.M.); (X.M.); Tel.: +86-311-80787400 (Z.M.)
| | - Xiaolong Ma
- School of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China
- Correspondence: (Z.M.); (X.M.); Tel.: +86-311-80787400 (Z.M.)
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7
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Amaraibi RJ, Joseph B, Kuhn JN. Techno-economic and sustainability analysis of siloxane removal from landfill gas used for electricity generation. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 314:115070. [PMID: 35452888 DOI: 10.1016/j.jenvman.2022.115070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 02/28/2022] [Accepted: 04/09/2022] [Indexed: 06/14/2023]
Abstract
A technoeconomic analysis (TEA) and life cycle assessment (LCA) was conducted on the use of landfill gas (LFG) for electricity generation using an internal combustion engine. This study provides insights that can guide LFG waste to energy (WTE) operators on decisions concerning installation of contaminant removal from LFG for electricity generation. Four scenarios were analyzed; the first (Scenario 1) was a facility with a single siloxane removal unit (SREU) sized for 6 months of continuous use, the second (Scenario 2) was a facility with parallel SREUs sized for one month of use, the third (Scenario 3) was a facility with no SREU, and the fourth was a facility that flared all LFG captured. The TEA revealed that the chiller cost was over 50% the total purchase cost of the LFG pre-treatment system. When the complete LFG to electricity process was analyzed, the internal combustion engine had the highest percentage of total capital investment and the total annual cost. For the base case, it became economically beneficial to install a SREU at facilities with LFG flowrates greater than ∼2000 m3/h. Sensitivity analysis showed that at a base case of 1700 m3/h, LFG (50% CH4), and 50 mg/m3 D4, the net income of facilities in Scenarios 1 to 3 became positive at an electricity sales price greater than 5.5 cents/kWh. LCA revealed that Scenario 2 had the greatest CO2 emission reduction. Scenario 3 is observed to save less CO2 emissions as biogas flowrate increases due to frequent engine shutdowns. Although there are differences in the global warming potential (GWP 100) for Scenarios 1 to 3, with Scenario 2 being the best and Scenario 3 being the worst, the differences are very small. For this reason, economics alone are sufficient in decision making.
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Affiliation(s)
- Rarosue J Amaraibi
- Heterogenous Catalysis & Materials Chemistry Group, Department of Chemical, Biological and Materials Engineering, University of South Florida, Tampa, USA
| | - Babu Joseph
- Heterogenous Catalysis & Materials Chemistry Group, Department of Chemical, Biological and Materials Engineering, University of South Florida, Tampa, USA.
| | - John N Kuhn
- Heterogenous Catalysis & Materials Chemistry Group, Department of Chemical, Biological and Materials Engineering, University of South Florida, Tampa, USA.
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8
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Cavali M, Libardi Junior N, Mohedano RDA, Belli Filho P, da Costa RHR, de Castilhos Junior AB. Biochar and hydrochar in the context of anaerobic digestion for a circular approach: An overview. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 822:153614. [PMID: 35124030 DOI: 10.1016/j.scitotenv.2022.153614] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/28/2022] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
Biochar and hydrochar are carbonaceous materials with valuable applications. They can be synthesized from a wide range of organic wastes, including digestate. Digestate is the byproduct of anaerobic digestion (AD), which is performed for bioenergy (biogas) production from organic residues. Through a thermochemical process, such as pyrolysis, gasification, and hydrothermal carbonization - HTC, digestate can be converted into biochar or hydrochar. The addition of either biochar or hydrochar in AD has been reported to improve biochemical reactions and microbial growth, increasing the buffer capacity, and facilitating direct interspecies electrons transfer (DIET), resulting in higher methane (CH4) yields. Both biochar and hydrochar can adsorb undesired compounds present in biogas, such as carbon dioxide (CO2), hydrogen sulfide (H2S), ammonia (NH3), and even siloxanes. However, an integrated understanding of biochar and hydrochar produced from digestate through their return to the AD process, as additives or as adsorbents for biogas purification, is yet to be attained to close the material flow loop in a circular economy model. Therefore, this overview aimed at addressing the integration of biochar and hydrochar production from digestate, their utilization as additives and effects on AD, and their potential to adsorb biogas contaminants. This integration is supported by life cycle assessment (LCA) studies, showing positive results when combining AD and the aforementioned thermochemical processes, although more LCA is still necessary. Techno-economic assessment (TEA) studies of the processes considered are also presented, and despite an expanding market of biochar and hydrochar, further TEA is required to verify the profitability of the proposed integration, given the specificities of each process design. Overall, the synthesis of biochar and hydrochar from digestate can contribute to improving the AD process, establishing a cyclic process that is in agreement with the circular economy concept.
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Affiliation(s)
- Matheus Cavali
- Department of Sanitary and Environmental Engineering, Federal University of Santa Catarina, 88040-970, Florianópolis, Santa Catarina, Brazil.
| | - Nelson Libardi Junior
- Department of Sanitary and Environmental Engineering, Federal University of Santa Catarina, 88040-970, Florianópolis, Santa Catarina, Brazil
| | - Rodrigo de Almeida Mohedano
- Department of Sanitary and Environmental Engineering, Federal University of Santa Catarina, 88040-970, Florianópolis, Santa Catarina, Brazil
| | - Paulo Belli Filho
- Department of Sanitary and Environmental Engineering, Federal University of Santa Catarina, 88040-970, Florianópolis, Santa Catarina, Brazil
| | - Rejane Helena Ribeiro da Costa
- Department of Sanitary and Environmental Engineering, Federal University of Santa Catarina, 88040-970, Florianópolis, Santa Catarina, Brazil
| | - Armando Borges de Castilhos Junior
- Department of Sanitary and Environmental Engineering, Federal University of Santa Catarina, 88040-970, Florianópolis, Santa Catarina, Brazil
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Microalgal Cultures for the Bioremediation of Urban Wastewaters in the Presence of Siloxanes. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19052634. [PMID: 35270319 PMCID: PMC8909507 DOI: 10.3390/ijerph19052634] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/20/2022] [Accepted: 02/23/2022] [Indexed: 11/25/2022]
Abstract
Microalgae are widely used in the bioremediation of wastewaters due to their efficient removal of pollutants such as nitrogen, phosphorus, and contaminants of emerging concern (CECs). Siloxanes are CECs that reach wastewater treatment plants (WWTPs), leading to the production of biogas enriched with these compounds, associated with the breakdown of cogeneration equipment. The biological removal of siloxanes from wastewaters could be a sustainable alternative to the costly existing technologies, but no investigation has been performed using microalgal cultures for this purpose. This study evaluated the ability of Chlorella vulgaris to bioremediate primary (PE) and secondary (SE) urban effluents and remove volatile methylsiloxanes (VMSs). C. vulgaris grew successfully in both effluents, and approximately 86% of nitrogen and 80% of phosphorus were efficiently removed from the PE, while 52% of nitrogen and 87% of phosphorus were removed from the SE, and the presence of VMSs does not seem to have a negative influence on nutrient removal. Three out of the seven of the analysed VMSs were detected in the microalgal biomass at the end of the PE assay. However, dodecamethylcyclohexasiloxane (D6) was the one that accumulated to a greater extent, since 48% of the initial mass of D6 was detected in the biomass samples. D6 is one of the most lipophilic VMSs, which might contribute to the higher adsorption onto the surface of microalgae. Overall, the results indicate C. vulgaris’ potential to remove specific VMSs from effluents.
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Vitamin C-Assisted Fabrication of Aerogels from Industrial Graphene Oxide for Gaseous Hexamethyldisiloxane Adsorption. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11188486] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Volatile methyl siloxanes (VMSs) as a trace impurity in biogas decreases its energy utilization, and thus need to be removed. In this paper, a one-step hydrothermal reduction was performed to produce three-dimensional reduced graphene oxide aerogels (rGOAs) using industrial-grade graphene oxide (IGGO) as raw material and vitamin C (VC) as a reductant to facilitate the fabrication of rGOAs. The synthesis of rGOAs was a simple, green, and energy-efficient process. The developed rGOAs were characterized using the Brunauer–Emmett–Teller method, Raman spectrometry, scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction measurements and contact angle. The results obtained showed that rGOA-1 with a VC/IGGO ratio of 1/1 (m/m) exhibited a hierarchical porous structure and super-hydrophobicity, yielding a high specific surface area (137.9 m2 g−1) and superior water contact angle (143.8°). The breakthrough adsorption capacity of rGOA-1 for hexamethyldisiloxane (L2, a VMS model) was 11 times higher than that of IGGO. Low inlet concentration and bed temperature were considered beneficial for the L2 adsorption. Interestingly, rGOA-1 was less sensitive to water, and it was readily regenerated for reuse by annealing at 80 °C. The rGOAs have been demonstrated to have great potential for the removal of siloxanes from biogas.
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Pascual C, Cantera S, Lebrero R. Volatile Siloxanes Emissions: Impact and Sustainable Abatement Perspectives. Trends Biotechnol 2021; 39:1245-1248. [PMID: 34167844 DOI: 10.1016/j.tibtech.2021.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 11/30/2022]
Abstract
Eliminating volatile siloxanes from gas emissions is increasingly important due to their persistent detrimental economic, societal, and environmental impacts. Although physicochemical technologies are currently the only commercially available abatement methods, recently developed biobased technologies are emerging as a more cost-effective and sustainable alternative to promote the removal of volatile siloxanes.
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Affiliation(s)
- Celia Pascual
- Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain; Institute of Sustainable Processes, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain
| | - Sara Cantera
- Laboratory of Microbiology, Wageningen University and Research Center, Campus Helix building 124 (Office 4030) Stippeneng 4, Wageningen 6708, WE, The Netherlands.
| | - Raquel Lebrero
- Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain; Institute of Sustainable Processes, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain.
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12
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Carbon Capture from Biogas by Deep Eutectic Solvents: A COSMO Study to Evaluate the Effect of Impurities on Solubility and Selectivity. CLEAN TECHNOLOGIES 2021. [DOI: 10.3390/cleantechnol3020029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Deep eutectic solvents (DES) are compounds of a hydrogen bond donor (HBD) and a hydrogen bond acceptor (HBA) that contain a depressed melting point compared to their individual constituents. DES have been studied for their use as carbon capture media and biogas upgrading. However, contaminants’ presence in biogas might affect the carbon capture by DES. In this study, conductor-like screening model for real solvents (COSMO-RS) was used to determine the effect of temperature, pressure, and selective contaminants on five DES’ namely, choline chloride-urea, choline chloride-ethylene glycol, tetra butyl ammonium chloride-ethylene glycol, tetra butyl ammonium bromide-decanoic acid, and tetra octyl ammonium chloride-decanoic acid. Impurities studied in this paper are hydrogen sulfide, ammonia, water, nitrogen, octamethyltrisiloxane, and decamethylcyclopentasiloxane. At infinite dilution, CO2 solubility dependence upon temperature in each DES was examined by means of Henry’s Law constants. Next, the systems were modeled from infinite dilution to equilibrium using the modified Raoults’ Law, where CO2 solubility dependence upon pressure was examined. Finally, solubility of CO2 and CH4 in the various DES were explored with the presence of varying mole percent of selective contaminants. Among the parameters studied, it was found that the HBD of the solvent is the most determinant factor for the effectiveness of CO2 solubility. Other factors affecting the solubility are alkyl chain length of the HBA, the associated halogen, and the resulting polarity of the DES. It was also found that choline chloride-urea is the most selective to CO2, but has the lowest CO2 solubility, and is the most polar among other solvents. On the other hand, tetraoctylammonium chloride-decanoic acid is the least selective, has the highest maximum CO2 solubility, is the least polar, and is the least affected by its environment.
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Wang G, Li G, Xing X, Zhang Z, Hao Z. Unraveling the adsorption and diffusion properties of hexamethyldisiloxane on zeolites by static gravimetric analysis. WATER RESEARCH 2021; 197:117097. [PMID: 33836298 DOI: 10.1016/j.watres.2021.117097] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 02/20/2021] [Accepted: 03/27/2021] [Indexed: 06/12/2023]
Abstract
Utilization of biogas from wastewater treatment plants (WWTPs) as a kind of renewable energy can effectively alleviate the escalating energy crisis. However, volatile methylsiloxanes (VMS) exist in biogas as impurities and hinder its efficient use. Adsorption is the main technology to achieve high-efficiency purification of VMS currently, yet studies on the adsorption processes and mechanisms are quite insufficient. Here, we use the static vapor adsorption method to investigate the adsorption performances and mechanisms of four typical zeolite adsorbents (Hbeta, SBA-15, MOR and MCM-41) towards hexamethyldisiloxane (L2), which is a representative of VMS. Results suggest the adsorption interaction of L2 and zeolite is closely related to the pore size of zeolite and follows the order of Hbeta > MCM-41 > SBA-15 > MOR. The adsorption rate constants of L2 on MCM-41 are larger than the others in the most relative pressure ranges. Besides, cyclic adsorption/desorption performances of L2 on MCM-41, SBA-15 and Hbeta show their super recycling properties. These studies would provide important information on designing an effective zeolite-L2 adsorption system, and are helpful to understand the deeper adsorption mechanisms of VMS on zeolites.
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Affiliation(s)
- Gang Wang
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, Research Center for Environmental Material and Pollution Control Technology, University of Chinese Academy of Sciences, Beijing 101408, China; School of Materials Design & Engineering, Beijing Institute of Fashion Technology, Beijing 100029, China
| | - Ganggang Li
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, Research Center for Environmental Material and Pollution Control Technology, University of Chinese Academy of Sciences, Beijing 101408, China
| | - Xin Xing
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, Research Center for Environmental Material and Pollution Control Technology, University of Chinese Academy of Sciences, Beijing 101408, China
| | - Zhongshen Zhang
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, Research Center for Environmental Material and Pollution Control Technology, University of Chinese Academy of Sciences, Beijing 101408, China.
| | - Zhengping Hao
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, Research Center for Environmental Material and Pollution Control Technology, University of Chinese Academy of Sciences, Beijing 101408, China.
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Impact of Compressed Natural Gas (CNG) Fuel Systems in Small Engine Wood Chippers on Exhaust Emissions and Fuel Consumption. ENERGIES 2020. [DOI: 10.3390/en13246709] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The projected increase in the availability of gaseous fuels by growing popularity of household natural gas (NG) filling stations and the increase in the production of gaseous biogas-derived fuels is conducive to an increase in the use of NG fuel. Currently, natural gas in various forms (compressed natural gas (CNG), liquefied natural gas (LNG)) is popular in maritime, rail and road transport. A new direction of natural gas application may be non-road mobile machines powered by a small spark-ignition engine (SI). The use of these engines in the wood chippers can cause the reduction of machine costs and emissions of harmful exhaust gases. In addition, plant material chippers intended for composting in bio-gas plants can be driven by the gas they are used to produce. The biogas can be purified to bio-methane to meet natural gas quality standards. The article presents the design of the natural gas supply system, which is an upgrade of the Lifan GX 390 combustion engine spark ignition engine (Four-stroke, OHV (over head valve) with a maximum power of 9.56 kW), which is a common representative of small gasoline engines. The engine is mounted in a cylindrical chipper designed for shredding branches with a maximum diameter of up to 100 mm, which is a typical machine used for cleaning work in urban areas. The engine powered by CNG and traditionally gasoline has been tested in real working conditions, when shredding cherry plum (Prunus cerasifera Ehrh. Beitr. Naturk. 4:17. 1789 (Gartenkalender4:189–204. 1784)). Their diameter was ca. 80 mm, 3-metere-long, and humidity content ca. 25%. The systems were tested under the same actual operating conditions, the average power generated by the drives during shredding is about 0.69 kW. Based on the recorded results, it was found that the CNG-fuelled engine was characterized by nitrogen oxides (NOx) emissions higher by 45%. The other effects of CNG were a reduction in carbon dioxide (CO2), carbon monoxide (CO) and hydrocarbon (HC) emissions of about 81%, 26% and 57%, respectively. Additionally, the use of CNG reduced fuel consumption by 31% and hourly estimated machine operating costs resulting from fuel costs by 53% (for average fuel price in Poland: gasoline: 0.99 EUR/L and CNG: 0.71 EUR/m3 on 08 November 2020). The modernization performed by the authors ensured the work of the drive unit during shredding, closer to the value of stoichiometric mixtures. The average (AVG) value of the air fuel ratio (AFR) for CNG was enriched by 1.2% (AVG AFR was 17), while for the gasoline engine the mixture was more enriched by 4.8% (AVG AFR was 14). The operation of spark-ignition (SI) combustion engines is most advantageous when burning stoichiometric mixtures due to the cooperation with exhaust aftertreatment systems (e.g., three-function catalytic converter). A system powered by CNG may be beneficial in systems adapting to operating conditions, used in low-power shredding machines, whose problem is increased HC emissions, and CNG combustion may reduce them. The developed system does not exceed the emission standards applicable in the European Union. For CO emissions expressed in g/kWh, it was about 95% lower than the permissible value, and HC + NOx emissions were 85% lower. This suggests that the use of the fuel in question may contribute to tightening up the permissible emission regulations for non-road machinery.
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