Biogas Flow Rate Research Articles

Performance evaluation of a control strategy for photosynthetic biogas upgrading in a semi-industrial scale photobioreactor

The validation of a control strategy for biogas upgrading via light-driven CO2 consumption by microalgae and H2S oxidation by oxidizing bacteria using the oxygen photosynthetically generated was performed in a semi-industrial scale (9.6 m3) photobioreactor. The control system was able to support CO2 concentrations lower than 2% with O2 contents ≤ 1% regardless of the pH in the cultivation broth (ranging from 9.05 to 9.50). Moreover, the control system was efficient to cope with variations in biogas flowrate from 143 to 420 L h−1, resulting in a biomethane composition of CO2 < 2.4%, CH4 > 95.5%, O2 < 1% and no H2S. Despite the poor robustness of this technology against failures in biogas and liquid supply (CH4 concentration of 67.5 and 70.9% after 2 h of biogas or liquid stoppage, respectively), the control system was capable of restoring biomethane quality in less than 2 h when biogas or liquid supply was resumed.

Performance of Sweet Potato’s Leaf-Derived Activated Carbon for Hydrogen Sulphide Removal from Biogas

In this study, sweet potato leaf activated carbon (SpLAC) was prepared by the chemical activation method using KOH and applied as an adsorbent for H2S removal from biogas. The study focused on the understanding of the effect of carbonization temperature (Tc), varying KOH : C activation ratio, flow rate (FR) of biogas, and mass of SpLAC on sample adsorption capacity. The BET analysis was performed for both fresh and spent activated carbons as well as for carbonized samples, which were not activated; also, the activated carbon was characterized by XRF and CHNS techniques. The results showed that removal efficiency (RE) of the SpLAC increased with increase carbonization temperature from 600 to 800°C and the mass of sorbent from 0.4 g to 1.0 g. The optimal test conditions were determined: 1.0 g of sorbent with a KOH : C ratio of 1 : 1, Tc=800°C, and FR=0.02 m3/h which resulted in a sorption capacity of about 3.7 g S/100 g of the SpLAC. Our findings corroborated that H2S removal was contributed not only by the adsorption process with the pore available but also by the presence of iron in the sample that reacted with H2S. Therefore, upon successful H2S sorption, SpLAC is suggested as a viable adsorbent for H2S removal from biogas.

Absorptive Desulfurization of Model Biogas Stream Using Choline Chloride-Based Deep Eutectic Solvents

The paper presents a synthesis of deep eutectic solvents (DESs) based on choline chloride (ChCl) as hydrogen bond acceptor and phenol (Ph), glycol ethylene (EG), and levulinic acid (Lev) as hydrogen bond donors in 1:2 molar ratio. DESs were successfully used as absorption solvents for removal of dimethyl disulfide (DMDS) from model biogas steam. Several parameters affecting the absorption capacity and absorption rate have been optimized including kinds of DES, temperature, the volume of absorbent, model biogas flow rate, and initial concentration of DMDS. Furthermore, reusability and regeneration of DESs by means of adsorption and nitrogen barbotage followed by the mechanism of absorptive desulfurization by means of density functional theory (DFT) as well as FT-IR analysis were investigated. Experimental results indicate that the most promising DES for biogas purification is ChCl:Ph, due to high absorption capacity, relatively long absorption rate, and easy regeneration. The research on the absorption mechanism revealed that van der Waal interaction is the main driving force for DMDS removal from model biogas.

Assessment of dual-fuel diesel engine performance by modulating biogas flow rate and intake charge preheating

ABSTRACT In this experimental study, the performance, combustion and emission of a diesel engine both in pure diesel mode (PDM) and in dual fuel mode (DFM) have been assessed and compared. The biogas flow rates (BFR) at various loads have been modulated in a manner to lower the biogas consumption at lower loads and increase the consumption at higher loads. The investigation has been carried out without and with preheating of the intake charge. The objective behind the modulation of BFR and intake charge preheating is to improve the diesel engine performance in DFM from part to higher loads. In this study with preheating, there is 10% increment of brake thermal efficiency (BTE) at 100% load in comparison to the one without preheating; while there is a reduction of 36.7% carbon monoxide (CO), 26.5% unburnt hydrocarbon (UHC) and 79.4% nitrogen oxides (NOx) at the same load.

Enhanced Adsorption of Carbon Dioxide from Simulated Biogas on PEI/MEA-Functionalized Silica.

A series of efficient adsorbents were prepared by a wet-impregnation method for CO2 separation from simulated biogas. A type of commercially available silica, named as FNG-II silica (FS), was selected as supports. FS was modified with a mixture of polyethyleneimine (PEI) and ethanolamine (MEA) to improve the initial CO2 adsorption capacity and thermal stability of the adsorbents. The influence of different adsorbents on CO2 adsorption performance was investigated by breakthrough experiments. Scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and N2 adsorption–desorption isotherm were used to characterize the silica before and after impregnating amine. Additionally, the thermal stability of adsorbents was measured by differential thermal analysis (TDA). Silica impregnated with mixtures of MEA and PEI showed increased CO2 adsorption performance and high thermal stability compared with those obtained from silica impregnated solely with MEA or PEI. With a simulated biogas flow rate of 100 mL/min at 0.2 MPa and 25 °C, FS-10%MEA-10%PEI exhibited a CO2 adsorption capacity of ca. 64.68 mg/g which increased by 81 % in comparison to FS-20%PEI. The thermal stability of FS-10%MEA-10%PEI was evidently higher than that of FS-20%MEA, and a further improvement of thermal stability was achieved with the increasing value of PEI/MEA weight ratio. It was showed that MEA was able to impose a synergistic effect on the dispersion of PEI in the support, reduce the CO2 diffusion resistance and thus increase CO2 adsorption performance. Additionally, if the total percentage of amine was the same, FS impregnated by different ratios of PEI to MEA did not exhibit an obvious difference in CO2 adsorption performance. FS-15%PEI-5%MEA could be regenerated under mild conditions without obvious loss of CO2 adsorption activity.

Removal of Hydrogen Sulfide from Biogas Using a Red Rock

The potential of red rock (RR) materials for the removal of H2S from biogas was studied. The rock samples were collected, sieved, and organized in various particle size ranges such as 0.32-250 μm, 250-500 μm, 500-750 μm, 750 μm-1 mm, and 1-1.5 mm. These samples were calcinated at the various temperatures as 500°C, 750°C, and 1000°C and then characterized for phase composition by energy-dispersive X-ray florescent technique, surface morphology by Zeiss Ultra Plus Field Emission Scanning Electron Microscopy (FE-SEM), and surface area by the Brunauer-Emmett-Teller (BET) method. The calcinated RR was filled in the bed reactor, and biogas was allowed to pass through the adsorbent while recording the inlet and exit concentration of H2S. The results show that particle size, calcination temperature, adsorbent mass, and biogas flow rate were parameters that influenced the removal efficiency and adsorption capacity of RR. The sample sieved at 0.32-250 μm and calcinated at a temperature of 1000°C showed 95% high removal efficiency and adsorption capacity of 0.37 g/100 g of the sorbent. Regeneration of spent materials when exposed to air, keep on by reuse in the column, appeared to have nearly similar removal efficiency as the original calcined sample. Thus, the overall performance of the material is promising, which is due to the presence of metals such as iron and magnesium, among others. Therefore, proving the successful elimination of contaminant, RR is an available material for biogas purification.

Study of performance criteria of serial configuration of two chemostats

This paper deals with thorough analysis of serial configurations of two chemostats. We establish an in-depth mathematical study of all possible steady states, and we compare the performances of the two serial interconnected chemostats with the performances of a single one. The comparison is evaluated under three different criteria. We analyze, at steady state, the minimization of the output substrate concentration, the productivity of the biomass and the biogas flow rate. We determine specific conditions, which depend on the biological parameters, the operating parameters of the model and the distribution of the total volume. These necessary and sufficient conditions provide the most efficient serial configuration of two chemostats versus one. Complementarily, this mainly helps to discern when it is not advisable to use the serial configuration instead of a simple chemostat, depending on: the considered criterion, the operating parameters fixed by the operator and the distribution of the volumes into the two tanks.

Study of performance criteria of serial configuration of two chemostats

This paper deals with thorough analysis of serial configurations of two chemostats. We establish an in-depth mathematical study of all possible steady states, and we compare the performances of the two serial interconnected chemostats with the performances of a single one. The comparison is evaluated under three different criteria. We analyze, at steady state, the minimization of the output substrate concentration, the productivity of the biomass and the biogas flow rate. We determine specific conditions, which depend on the biological parameters, the operating parameters of the model and the distribution of the total volume. These necessary and sufficient conditions provide the most efficient serial configuration of two chemostats versus one. Complementarily, this mainly helps to discern when it is not advisable to use the serial configuration instead of a simple chemostat, depending on: the considered criterion, the operating parameters fixed by the operator and the distribution of the volumes into the two tanks.

Study of performance criteria of serial configuration of two chemostats

This paper deals with thorough analysis of serial configurations of two chemostats. We establish an in-depth mathematical study of all possible steady states, and we compare the performances of the two serial interconnected chemostats with the performances of a single one. The comparison is evaluated under three different criteria. We analyze, at steady state, the minimization of the output substrate concentration, the productivity of the biomass and the biogas flow rate. We determine specific conditions, which depend on the biological parameters, the operating parameters of the model and the distribution of the total volume. These necessary and sufficient conditions provide the most efficient serial configuration of two chemostats versus one. Complementarily, this mainly helps to discern when it is not advisable to use the serial configuration instead of a simple chemostat, depending on: the considered criterion, the operating parameters fixed by the operator and the distribution of the volumes into the two tanks.

Study of performance criteria of serial configuration of two chemostats

This paper deals with thorough analysis of serial configurations of two chemostats. We establish an in-depth mathematical study of all possible steady states, and we compare the performances of the two serial interconnected chemostats with the performances of a single one. The comparison is evaluated under three different criteria. We analyze, at steady state, the minimization of the output substrate concentration, the productivity of the biomass and the biogas flow rate. We determine specific conditions, which depend on the biological parameters, the operating parameters of the model and the distribution of the total volume. These necessary and sufficient conditions provide the most efficient serial configuration of two chemostats versus one. Complementarily, this mainly helps to discern when it is not advisable to use the serial configuration instead of a simple chemostat, depending on: the considered criterion, the operating parameters fixed by the operator and the distribution of the volumes into the two tanks.

Study of performance criteria of serial configuration of two chemostats

This paper deals with thorough analysis of serial configurations of two chemostats. We establish an in-depth mathematical study of all possible steady states, and we compare the performances of the two serial interconnected chemostats with the performances of a single one. The comparison is evaluated under three different criteria. We analyze, at steady state, the minimization of the output substrate concentration, the productivity of the biomass and the biogas flow rate. We determine specific conditions, which depend on the biological parameters, the operating parameters of the model and the distribution of the total volume. These necessary and sufficient conditions provide the most efficient serial configuration of two chemostats versus one. Complementarily, this mainly helps to discern when it is not advisable to use the serial configuration instead of a simple chemostat, depending on: the considered criterion, the operating parameters fixed by the operator and the distribution of the volumes into the two tanks.

Removal of Hydrogen Sulfide from Biogas Using a Bubbling Tank Fed with Aerated Wastewater

ABSTRACT The work develops a simple bubbling tank scrubber that is fed with aerating wastewater for the removal of hydrogen sulfide (H2S) in biogas. A 2,000 L plastic tank, in which fixed liquid levels 0.80 and 1.0 m and volumes of 1.1 and 1.4 m3 was kept, was used for the scrubbing tests. A polyvinyl chloride (PVC) pipe with holes of 1 mm diameter was used to sparge the biogas into the tank liquid. Results indicate that with an influent liquid of pH 7.5–7.7, a flow rate of 23–25 L min–1, influent biogas flow rates of 0.050–0.200 m3 min–1, and a H2S concentration of 907 ± 212 ppm, the pH of the effluent liquid stabilized at 6.6–6.9. With gas/liquid rate ratio of 2–8 m3 m–3 liquid and volumetric gassing intensities of 0.04–0.20 m3 m–3 liquid min–1, average H2S removals of 86–71% were obtained. Absorption of CO2 in the tested digester gas into the scrubbing liquid caused a decrease in the pH, thus decreasing the H2S removal efficiency. Increasing pH of the scrubbing liquid to 8.0 improved the H2S removal efficiency to as high as 99%.

Feasibility Study of Biogas Upgrading Facility Development from Anaerobic Digestion of Palm Oil Mill Effluent in Indonesia

Palm Oil Mill Effluent (POME) can be processed using anaerobic digestion technologies to produce biogas. Biogas, that was produced from the anaerobic digestion process from POME, contained a high impurity CO2 30% - 45% and H2S around 1500 - 3000 ppm. In this research, a feasibility study was conducted to develop an anaerobic digestion facility from POME and biogas upgrading facility using absorption-based technologies: water scrubbing and amine scrubbing. The technical study was carried out using Aspen Plus software with a biogas flow rate of 0.8 MMCFD and methane content in biogas of 65% mole fraction. The target biomethane product contains CH4> 95%, CO2< 5%, H2S < 10 ppm and water content<10 lb/MMscf. The investment and operating costs for an aerobic digestion facilities use data from previous biogas projects that have been registered in the UNFCCC CDM (Clean Development Mechanism) project in Indonesia. Meanwhile, the biogas upgrading facility's investment cost is obtained from the simulation results using Aspen Plus software. An economic study was conducted to calculate the gas price of biomethane with an expected internal rate of return of 12%. The purity level of biomethane from water scrubbing facilities reached 97.38% and from amine scrubbing facilities reached 99.93%. From the simulation and calculation result, the lowest gas price of biomethane was $ 13.06/MMB tu using amine scrubbing technology.

Emission from Compression Ignition Engine using Biogas Blends with Diesel as a Fuel

A study on performance and emission of compression ignition (CI) engine has been made by utilizing biogas blends at different loads. The flow rate of biogas with air was important parameter to get the desired results. The blend of 30% with diesel was optimum which yielded optimum emission characteristics. Higher specific fuel consumption and lower brake thermal efficiency was observed when the proportion of biogas mixes with diesel in comparison with neat diesel. The out coming results from the experimental investigation exhibited reduction in NOx emission and smoke opacity. The other emissions hydrocarbon (HC) and carbon monoxide (CO) has been higher than diesel. The use of biogas as an alternative fuel in correct proportion with diesel can meet the energy demand on scarcity of conventional fuel.

Impact of Biogas Blends with Diesel on Emission of Compression Ignition Engine

Main objective of the work was to investigate the output like emission from compression ignition engine which has been run by diesel as well as the blends of biogas with diesel. Volume flow rate of biogas with petrol as a major parameter to reach the expected outcome. The engine was operated with diesel, and blends of biogas 15%, 25% and 35% with petrol. The study focused on the variation of outputs hydrocarbon, carbon monoxide(CO) Nitrous oxides(NOX) and smoke for the brake power generated by the engine. The engine exhibits better results when the proportion of biogas was increased.

Micro-combined heat and power using dual fuel engine and biogas from discontinuous anaerobic digestion

The modeling of the Micro-CHP unit operating in dual-fuel mode is performed based on experimental results carried out at the laboratory scale. The engine tests were performed on an AVL engine, with a maximum power of 3.5 kW, using conventional diesel as pilot fuel and synthetic biogas as primary fuel. The biogas flow rate is evaluated using the experimental results from the literature, based on the anaerobic digestion in batch reactor of a mixture of 26% of Oat Straw and 74% of Cow Manure, diluted to contain only 4% of volatile solid.The engine operation was modeled using the Artificial Neuron Network (ANN) method. Experimental engine tests were used as a database for training and validation phases of ANN models. Three different ANN models are developed to model respectively the pilot fuel flow rate, the airflow rate and the exhaust gas temperature. Engine power output, biogas flow rate and biogas methane content were used as the same input layer.Given that the evolution of the biogas flow evolves along the entire digestion duration (50 days), the simulation work is performed by varying the number of digesters to be used in parallel mode. It is obtained that the optimal operation condition, minimizing the number of digesters and using less than 10% of the energy from diesel fuel, is to use 5 digesters and run the engine under load of 70%. It is concluded that a micro-CHP unit of 1 kWe, requires a dual fuel generator with a nominal power of 1 kWe, five digesters and a daily availability of effluents of 171 kg/day, consisting of 45 kg/day of oat straw and 126 kg/day of cow manure. It can also produce up to 2.45 kW of thermal power from the exhaust.

Removal of hydrogen sulfide using a photocatalytic livestock biogas desulfurizer

The objective of this study was to develop a simple operating photocatalytic biogas desulfurizing reactor (PDR) using sol-gel preparation assay in coordination with biogas absorption chiller. Hydrogen sulfide in biogas can be oxidized to SO2 by photocatalytic oxidation of TiO2-coated carriers with UV irradiation. This PDR method is the lowest maintenance cost and simple operation for small biogas consumption users water than packed scrubber or granular ferric oxide filter. Experimental results showed that H2S removal efficiency by the first PDR was 99.1 ± 1.1, 92.9 ± 2.9, 88.2 ± 3.6, 84.1 ± 2.3, and 82.7 ± 9.4% under biogas flow rate at 1, 2, 3, 4, and 5 L/min, respectively. Removal efficiency of H2S at biogas flow rate at 1 L/min was significantly different from the other biogas flow rate sets (P < 0.05). Experimental results showed that total H2S removal efficiency for all biogas flow sets was more than 99% by the dry PDR. Thus, this implies that the photocatalytic reactor can be applied to remove H2S from biogas. The successful development of the PDR can help to promote utilization efficiency of livestock biogas and reduce livestock’s greenhouse gas emissions.

Adsorption of Sulphur in Biogas by Activated Carbon Derived From Mangrove Fruits (Rhizopora stylosa) as Solid Residue of Natural Dyes Extraction

Hydrogen sulfide (H2S) is considered as impurity in biogas. H2S could react to form sulfur dioxide (SO2) and sulfuric acid (H2SO4) during the burning process. The corrosive property of these compounds possibly cause damage the power plant system. Overcoming this problem, activated carbon impregnated with KOH has been proven to work very well in adsorbing H2S. On the other hand, mangrove fruits pulp residue from the natural dyes extraction process has not utilized. Mangrove (Rhizopora stylosa) fruits contain about 50% fixed carbon which is possibly made as activated carbon. The purposes of this research were to determine the adsorption efficiency of H2S in biogas using activated carbon derived from mangrove fruits residue and to determine isotherm equilibrium constants for adsorption. The small scale adsorption devices consist of cooler, flow stabilizer, flow regulator, flow meter and column adsorber. At certain flow rate, biogas was sampled in every 10 minutes and then analyzed using portable H2S gas analyzer. Temperatures of biogas entered the adsorption column were in the range of 33-34oC. The optimum biogas flow rate was 4 liter per minute (lpm) for 250 grams (16 cm of height) of activated carbon. We found the adsorption efficiency was decreased by time and still reached 79.6% for 50 minutes contact time. Based on coefficient of correlation value (R2) on isotherm model, Langmuir model is more suitable for the H2S adsorption of biogas in this study. We found the Langmuir equilibrium constant k was 0.033 and maximum adsorption capacity (x/m)max was 0.284 mg/mg.

Development of a control strategy to cope with biogas flowrate variations during photosynthetic biogas upgrading

The design and evaluation of a control system for a photosynthetic biogas upgrading unit was successfully carried out in this study. This control system ensured a specific biomethane quality under any disturbance in the biogas flowrate. The recycling liquid flowrate, and indirectly the liquid to biogas (L/G) ratio, was selected as the manipulated variable in order to maintain the CO2 and O2 content of biomethane, and therefore comply with the requirements for its use as natural gas substitute (≤2.5% and ≤1.0%, respectively). The control system was able to maintain the biomethane CO2 content below the set point value under a stepwise increase in the biogas flowrate from 60 to 150 ml min−1, together with negligible H2S concentrations and an O2 stripping from the recycling liquid to the biomethane lower than 1%, thus obtaining a consistent biomethane quality over time. On the contrary, the biomethane CO2 content increased up to 13.2% under this stepwise increase in the biogas flowrate without control system. Successful results were also obtained when the control system was challenged with stepwise surges in the biogas flowrate between 60 and 120 ml min−1 under different temperatures (15 and 35 °C) and inorganic carbon concentrations (1500, 500 and 100 mg L−1) when the recycling liquid entering the absorption column presented a pH = 10. However, the high liquid flowrates required at a cultivation broth pH of 8.5 as a result of the low CO2 mass transfer led to an excessive O2 desorption to the biomethane, resulting in biomethane O2 contents >1%.

Harga Jual BioCNG dari Palm Oil Mill Effluent sebagai Sumber Energi Alternatif

&lt;p class="judulabstraking"&gt;Indonesia as the largest producer of palm oil, produces huge palm oil wastewater. The wastewater produces biogas which contributes to global warming, and the utilization of the biogas reduces GHG emissions of methane gas. By increasing the concentration of methane gas in the biogas, and increasing the gas pressure of biomethane, so-called bioCNG (Compressed Natural Gas), the gas utilization easier in the transportation and the energy content of the gas increases. In this paper, an assessment of the economics of bioCNG production facility in the Palm Oil Mill (POM) with a capacity of 60 tons/hour was conducted. The investment cost is estimated based on the biogas flow rate produced from an aerobic digester in the POM. By using a covered lagoon technology for anaerobic digester, and technology of membrane for gas purification, and based on the natural gas trading regulations, the selling price of bioCNG is determined by 10.27 USD/MMBTU with an IRR of 12%. This price can compete with the prices of other fossil fuels. However, the support from government regulations are still needed to utilize bioCNG as a new renewable fuel that can contribute to national energy security, GHG reduction, and achievement of the mix energy target.&lt;/p&gt;