Long-term influence of high alkalinity on the performance of photosynthetic biogas upgrading

Rodero, María del Rosario; Severi, Cristian Alfredo; Rocher-Rivas, Ricardo; Quijano, Guillermo; Muñoz, Raúl

doi:10.1016/j.fuel.2020.118804

Cited by 24 publications

(10 citation statements)

References 41 publications

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“…The high CO2 removal efficiencies observed in stages C to E were supported by the high pH and buffer capacity of the cultivation broth under the prevailing operational conditions. These values here achieved were higher than those reported by Rodero et al, (2020), who observed CO2 concentrations between 1.5 and 4.4% in a similar indoors experimental set-up with a higher IC concentration in the cultivation broth (1203-3814 mg L -1 ). It should be also stressed that the CO2-REs observed in stages A to C were higher than those previously described during winter by Marín et al, (2018a), who recorded CO2 REs between 63.6% and 85.9% in a similar outdoors photobioreactor configuration during winter without greenhouse.…”

Section: Biogas Upgrading 13contrasting

confidence: 82%

Innovative operational strategies in photosynthetic biogas upgrading in an outdoors pilot scale algal-bacterial photobioreactor

et al. 2021

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Section: Biogas Upgrading 13contrasting

confidence: 82%

Innovative operational strategies in photosynthetic biogas upgrading in an outdoors pilot scale algal-bacterial photobioreactor

et al. 2021

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“…observed in stages C to E were supported by the high pH and buffer capacity of the cultivation broth under the prevailing operational conditions. These values here achieved were higher than those reported byRodero et al, (2020), who observed CO2 concentrations between 1.5 and 4.4% in a similar indoors experimental set-up with a higher IC concentration in the cultivation broth (1203-3814 mg L -1 ). It should be also stressed that the CO2-REs observed in stages A to C were higher than those previously described during winter by Marín et al, (2018a), who recorded CO2 REs between 63.6% and 85.9% in a similar outdoors photobioreactor configuration during winter without greenhouse.…”

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confidence: 83%

Innovative technologies for biogas upgrading

Jesús¹,

Fernando²

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The biogas from the anaerobic digestion of wastewaters or organic solid waste represents a key renewable energy vector in order to mitigate the use of fossil fuels. Biogas upgrading is required prior use as a vehicle fuel or injection into natural gas networks. In this context, several international regulations exist setting the maximum and minimum allowed concentrations of each biomethane component depending on its final application.Multiple physical-chemical and biological technologies are nowadays commercially available in order to remove CO2 and H2S from biogas. However, most of these technologies must be sequentially implemented to remove both H2S, CO2 and trace contaminants such as siloxanes or volatile organic contaminants. In this sense, this thesis focuses on the study of new technologies supporting the simultaneously removal of H2S and CO2 from biogas in a single step process, in a sustainable manner and with low operating costs.The state-of-the-art of biogas upgrading technologies is presented in the Introduction section. The objectives, approach and strategies followed in this thesis are summarized in the Aims and Scope section.In Chapter 1, the bioconversion of biogas to biomethane coupled to centrate treatment was evaluated during summer time in an outdoors pilot scale high rate algal pond (HRAP) interconnected to an external CO2-H2S absorption column (AC) via settled broth recirculation. CO2-removal efficiencies ranged from 50 to 95% depending on the alkalinity of the cultivation broth and environmental conditions, while a complete H2S removal was achieved regardless of the operational conditions. A maximum CH4 concentration of 94%, along with a limited O2 and N2 stripping, were recorded in the upgraded biogas at recycling liquid-to-biogas (L/G) ratios in the AC of 1 and 2. Process operation at a constant biomass productivity of 15 g m -2 d -1 (controlled via settler waste) and the minimization of effluent generation supported high carbon and nutrient recoveries

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“…However, as is evident from the literature, a similar trend exists between N 2 and O 2 stripping, resulting in comparable percentages of the respective gases in the upgraded biomethane. 17,23,25 For this, it can be speculated that a similar N 2 concentration (∼0.5%) can be envisaged in the upgraded biomethane under similar operating conditions with actual biogas.…”

Section: ■ Resultsmentioning

confidence: 93%

“…This is consistent with the observations by Majumder (2016), 62 who reported a nominal gas holdup at low superficial gas velocities. Mathematically, a theoretical estimate of the gas holdup, Δ g , was obtained to be 0.006 via eq 22, as given by Chisti (1989) 63 for bubble column bioreactors operating at u G < 0.05 m/s Δ = u 2.47 g G 0.97 (23) Improvements in sparger designs to decrease the bubble diameter and hence increase the gas−liquid contact could result in higher oxygen stripping. However, for such low gas holdup, scale-up of the bubble column reactor with minimal errors for similar sparger designs can be envisaged.…”

Section: ■ Resultsmentioning

confidence: 99%

Design, Commissioning, and Performance Assessment of a Lab-Scale Bubble Column Reactor for Photosynthetic Biogas Upgrading with Spirulina platensis

Bose

O’Shea

Lin

et al. 2021

Ind. Eng. Chem. Res.

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The two-step bubble column-photobioreactor photosynthetic biogas upgrading system can enable simultaneous production of biomethane and value-added products from microalgae. However, due to the influence of a large number of variables, including downstream processes and the presence of microalgae, no unanimity has been reached regarding the performance of bubble column reactors in photosynthetic biogas upgrading. To investigate this further, the present work documents in detail, the design and commissioning of a lab-scale bubble column reactor capable of treating up to 16.3 L/h of biogas while being scalable. The performance of the bubble column was assessed at a pH of 9.35 with different algal densities of Spirulina platensis at 20 °C in the presence of light (3–5 klux or 40.5–67.5 μmol m –2 s –1 ). A liquid/gas flow (L/G) ratio of 0.5 allowed consistent CO 2 removal of over 98% irrespective of the algal density or its photosynthetic activity. For lower concentrations of algae, the volumetric O 2 concentration in the upgraded biomethane varied between 0.05 and 0.52%, thus providing grid quality biomethane. However, for higher algal concentrations, increased oxygen content in the upgraded biomethane due to both enhanced O 2 stripping and the photosynthetic activity of the microalgae as well as clogging and foaming posed severe operational challenges.

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Long-term influence of high alkalinity on the performance of photosynthetic biogas upgrading

Cited by 24 publications

References 41 publications

Innovative operational strategies in photosynthetic biogas upgrading in an outdoors pilot scale algal-bacterial photobioreactor

Innovative operational strategies in photosynthetic biogas upgrading in an outdoors pilot scale algal-bacterial photobioreactor

Innovative technologies for biogas upgrading

Design, Commissioning, and Performance Assessment of a Lab-Scale Bubble Column Reactor for Photosynthetic Biogas Upgrading with Spirulina platensis

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