Optimization Of Hydrogen Production Research Articles

Reactor conceptual design by optimization for hydrogen production through intensified sorption- and membrane-enhanced water-gas shift reaction

In this feasibility study, a novel industrial-scale reactor structure for continuous hydrogen production via intensified water-gas shift (WGS) reaction is proposed. It considers both trickling calcium-oxide sorbent for carbon dioxide removal (SOR) and Pd-based membrane for hydrogen separation (MEM). It is shown that WGS, SOR, MEM, and cooling can be decoupled with a special reactor superstructure mathematically represented with the pseudo-homogenous one-dimensional model. The final reactor structure and operating conditions are determined by using rigorous multi-objective optimization. Two objective functions take all main costs into account (total reactor volume and respective volumetric fractions for the catalyst, sorbent, and membrane) and the main benefit (hydrogen yield). The results show that the best cost-benefit relation can be achieved with the two-module reactor and combined WGS and SOR processes, with 95% carbon monoxide conversion (64% higher than the equilibrium conversion at the same conditions) and the outlet-stream containing only 0.7% of carbon dioxide.

Optimization of hydrogen production from food waste using anaerobic mixed cultures pretreated with waste frying oil

The fermentation of food waste by anaerobic mixed cultures pretreated with waste frying oil (WFO) was examined in this study. Waste frying oil was used as a stressing agent to suppress hydrogenotrophic methanogens and enrich H2-producing bacteria. Lipid-rich compounds can be adsorbed onto the cell wall of some species, including methanogens, and they can reduce the permeability of the membranes and limit nutrient transport into cells. The optimization of H2 yield was performed using a three-factor, three-level Box-Behnken design method. Initial pH, pretreatment duration and waste frying oil concentration were considered the experimental factors. Pretreatment with waste frying oil decreased the production of CH4 significantly and, in turn, improved H2 accumulation. The response surface model predicted complete inhibition of methanogens with 7.74 g/L waste frying oil, an initial pH of 5.5 and a duration of 42.67 h for the pretreatment conditions. Applying these conditions led to an experimental H2 yield of 71.34 mL/gVS, which was significantly higher than that of untreated cultures (12.97 mL/gVS).

Study of microbial dynamics during optimization of hydrogen production from food waste by using LCFA-rich agent

In dark fermentation of food waste, changes in microbial community composition and dynamics were studied, after inoculum pre-treatment with waste frying oil (WFO). The microbial diversity in the raw sludge was the highest, considering that all genera with abundances higher than 0.1% contributed to only 37.42% of the total diversity. After inoculum pre-treatment with WFO, many genera were inhibited; however, no effect was observed on spore-forming fermentative bacteria. In addition, none-spore-forming H2 producers were enriched significantly after inoculum pre-treatment, while spore-forming H2 producing bacteria (e.g. Clostridium spp.) remained almost unchanged. The predominant OTUs after dark fermentation were Clostridium sp. (27.24%), Aeromonas sp. (13.43%) and Chromobacterium sp. (12.00%).

Optimization of Hydrogen Production Through Methane Steam Reforming in a Membrane Reactor

Optimization of Hydrogen Production Through Methane Steam Reforming in a Membrane Reactor

Optimization of hydrogen production over TiO2 supported copper and nickel oxides: effect of photoelectrochemical features

Low-cost solar hydrogen production through water splitting using photo-electrochemical (PEC) cell offers a clean and renewable source of energy. However, its low performance remains a primary concern. Solar hydrogen production of TiO2 supported copper and nickel oxides photoanod (Cu–Ni/TiO2) was significantly influenced by photoanode fabrication and reaction parameters. To maintain the optimum operating conditions of PEC cell for practical application, we systematically investigated the effect of sintering temperature, photoanode thickness, electrolyte concentration, and applied voltage on hydrogen production over 5 mol% Cu–Ni/TiO2 and PEC characteristics, including charge carrier transfer resistance, photocurrent density, and flat band potential. Findings reveal that the optimized sintering temperature for hydrogen production was 400 °C due to low charge transfer resistance and more excited electrons at the electrode/electrolyte interface. The photocatalyst with the four layers of printed 5 mol% Cu–Ni/TiO2 (thickness ~ 24.8 µm) improved the photocatalytic performance, highlighting the importance of the number of excited electrons and the surface area of the photocatalyst. Furthermore, applied voltage exerted the most significant effect on hydrogen production up to 24.9 mL at the optimum level of 3.4 V by minimizing the recombination rate of electron–hole pairs. The stability of the photoanode was tested under the optimum conditions for 4 days and the maximum accumulative hydrogen of 443.4 mL was produced over this highly stable photoanode.

Optimization of hydrogen production from three reforming approaches of glycerol via using supercritical water with in situ CO2 separation

A pathway for hydrogen production from supercritical water reforming of glycerol integrated with in situ CO2 removal was proposed and analyzed. The thermodynamic analysis carried out by the minimizing Gibbs free energy method of three glycerol reforming processes for hydrogen production was investigated in terms of equilibrium compositions and energy consumption using AspenPlus™ simulator. The effect of operating condition, i.e., temperature, pressure, steam to glycerol (S/G) ratio, calcium oxide to glycerol (CaO/G) ratio, air to glycerol (A/G) ratio, and nickel oxide to glycerol (NiO/G) ratio on the hydrogen production was investigated. The optimum operating conditions under maximum H2 production were predicted at 450 °C (only steam reforming), 400 °C (for autothermal reforming and chemical looping reforming), 240 atm, S/G ratio of 40, CaO/G ratio of 2.5, A/G ratio of 1 (for autothermal reforming), and NiO/G ratio of 1 (for chemical looping reforming). Compared to three reforming processes, the steam reforming obtained the highest hydrogen purity and yield. Moreover, it was found that only autothermal reforming and chemical looping reforming were possible to operate under the thermal self-sufficient condition, which the hydrogen purity of chemical looping reforming (92.14%) was higher than that of autothermal reforming (52.98%). Under both the maximum H2 production and thermal self-sufficient conditions, the amount of CO was found below 50 ppm for all reforming processes.

Metagenomic analysis and optimization of hydrogen production from sugarcane bagasse

The substrate and yeast extract (YE) concentrations of a batch reactor were changed according to a central composite design in order to optimize the conversion of sugarcane bagasse (SCB) into hydrogen. The optimum hydrogen production (1.50 mmol/L) was obtained using 2.77 and 5.84 g/L of YE and SCB, respectively. Taxonomic analysis using the SEED database indicated that Clostridium (33% of total communities) and Methanothermobacter (40% of archaeal community) were the most abundant genera in the high hydrogen performance reactor. Key microorganisms and related pathways involved in all steps of the anaerobic digestion were further revealed and may help drive sugarcane bagasse bioconversion.

Optimization of hydrogen production by photocatalytic steam methane reforming over lanthanum modified Titanium (IV) oxide using response surface methodology

In this study, the optimization of hydrogen production by photocatalytic steam methane reforming over Lanthanum modified TiO2 has been investigated using response surface methodology. The La/TiO2 photocatalysts were synthesized using wet impregnation method and characterized for physicochemical and photocatalytic properties by N2 physisorption, X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX), and ultraviolet-visible (UV-vis) spectroscopy. The characterization shows that the La/TiO2 possesses appropriate properties to be used as photocatalysts. The photocatalysts were employed in the optimization studies of hydrogen production by photocatalytic steam methane reforming. The effects of irradiation time (10–150 min), metal loading (1–3%), methane concentration (10–50%), and steam concentration (0.5–1.5%) on the rate of hydrogen production were determined employing Box-Behnken experimental design. The application of the RSM resulted in the formulation of four models out which the quadratic model was adjudged to adequately fit the experimental data. A further statistical analysis of the quadratic model established the significance of the model with p-value far less than 0.05 and coefficient of determination (R2) of 0.975. A non-significant lack of fit obtained for the model further confirm the suitability of the quadratic model in fitting the experimental data. At the desirability function of 1, optimum conditions of 146.15 min, 2.94%, 22.83% and 1.24% for irradiation time, metal loading, methane concentration, and steam concentration, respectively resulted in the production of 2.42 μmol of hydrogen/min.

Effect of pH on optimization of photofermentative hydrogen production by co-culture of Rhodobacter sphaeroides-NMBL-02 and Bacillus firmus-NMBL-03.

Rhodobacter sphaeroides NMBL-02, photosynthetic purple non sulfur (PNS) bacteria and associated Bacillus firmus NMBL-03 were isolated from water sample collected from 15-20 inches beneath the surface of ponds from Northern region of India in modified Sistrom's media (120 ml) containing 3 g/L malate and 1.2 g/L ammonium sulfate. The isolation was done in air tight serum bottles (120 ml) under tungsten bulb (1.8 kLux light intensity) at 30 oC ± 2 oC. The PNS and heterotrophic bacteria associated with the culture was purified by clonal selection method and characterized by 16S rDNA sequencing. The PNS isolate was identified as Rhodobacter sphaeroides NMBL-02 (ID: 1467407, Accession BANKIT: JN256030) and associated heterotroph as Bacillus firmus NMBL-03 (Gene Bank Accession no.: JN 256029). The effect of initial medium pH on optimization of hydrogen production was investigated in batch process. The maximum hydrogen potential and hydrogen production rate was 2310 ± 55 ml/L and 4.75 ml/L culture/h respectively using glutamate (1.7 mmol/L) as nitrogen source and malate (22.38 mmol/L) as carbon source with 76.39% malate conversion efficiency at initial medium pH 5.0. This co-culture has the ability to produce significant amount of hydrogen in the pH range of 5.0 to 10.0 with 76.39% to 35.71% malate conversion respectively.

Optimization of hydrogen production from agricultural wastes using mixture design

Abstract: Hydrogen production from food waste, cattle manure, potato pulp and pig manure was optimized through using mixture design in this study. The synergic and antagonistic effects of the four substrates on hydrogen yield, substrate conversion efficiency and pH were evaluated. The results showed that the optimal proportion of food waste, cattle manure, potato pulp and pig manure were 61.6%, 38.4%, 0, and 0, respectively. Under the optimal condition, hydrogen yield of 21.0 mL/g VS with VS reduction of 29.4% and pH of 5 could be obtained. The interaction between food waste and cattle manure had strongest synergistic effects. Hydrogen was mainly produced by acetic-butyric metabolic pathway, and ammonification of protein played an important role in the maintenance of pH. Keywords: hydrogen, biohydrogen production, agricultural waste, dark fermentation, mixture design DOI: 10.3965/j.ijabe.20171003.2688 Citation: Liu S, Wang C Y, Yin L L, Li W Z, Wang Z J, Luo L N. Optimization of hydrogen production from agricultural wastes using mixture design. Int J Agric & Biol Eng, 2017; 10(3): 246–254.

Optimization of Hydrogen Production from Nigerian Crude Oil Samples Through Continuous Catalyst Regeneration (CCR) Reforming Process Using Aspen Hysys

The aim of this paper is to increase the level of hydrogen produced in the refinery from heavy treated Naphtha of Nigerian crude oil during catalytic reforming process. An existing continuous catalyst regeneration catalytic reforming process plant with four beds reactor was simulated using Aspen Hysys while treated heavy Napthene from Bonga Crude and Bonny Crude were used as feed for the process. The temperature of reactors for the process was varied between 430 – 540°C and the outlet concentrations of hydrogen (Vol.%) produced was recorded. It was observed that an increase in temperature lead to an increase in the concentration of hydrogen produced as the volume of hydrogen at 430°C was 23.46% volume while at 540°C it was 51.38% volume showing a significant increase in the aromatic yield level. The results also showed that the naphthene content of feed affects the volume of hydrogen produced which made Bonga crude a better source for hydrogen when compared with Bonny crude.

Optimization of hydrogen production by the psychrophilic strain G088

In this study, the response surface method with a Box-Behnken design was applied to evaluate the effect of temperature, pH and glucose concentration to optimize hydrogen production by psychrophilic strain G088 ([EU636029], which is closely related to Polaromonas rhizosphaerae [EF127651]). Biohydrogen production was performed in 120 cm3 serological bottles with a production medium containing 2.75 g/dm3 tryptone, 0.25 g/dm3 yeast extract and glucose concentration in the range of 10–40 g/dm3, pH 3.0–8.0 and temperature 13–37 °C. According to the mathematical model, temperature 26.30 °C, pH 6.2 and glucose 25.31 g/dm3 were the optimum conditions for a predict hydrogen production (HP) of 503.34 cm3, a hydrogen production rate (HPR) and hydrogen yield (HY) of 37.91 cm3/dm3/h and 1.93 mol H2/mol glucose, respectively. The linear effect of pH and quadratic effect of temperature, pH and glucose concentration were the most significant terms affecting HP. Otherwise HPR was affected only by the quadratic terms of temperature and glucose concentration, while HY was affected by the linear and quadratic effect of the three factors. The optimal production conditions were experimentally tested by triplicate corroborating the correspondence with the predicted value by the mathematical model. The experimental values for hydrogen production, yield and rate under these conditions were 513 ± 12.48 cm3, 36.5 ± 4.10 cm3/dm3/h and 1.81 ± 0.04 mol H2/mol glucose, respectively.

Optimization hydrogen production over visible light-driven titania-supported bimetallic photocatalyst from water photosplitting in tandem photoelectrochemical cell

Solar hydrogen production was investigated over a Cu-Ni doped TiO2 photocatalyst from water photosplitting in a tandem photoelectrochemical cell, which was made up by connecting a modified photoelectrochemical cell to dye solar cell in a series. A mathematical representation for preparation parameters for hydrogen production was successfully generated. Optimization of hydrogen production was conducted with varying preparation parameters of Cu-Ni doped TiO2 photocatalyst including molar ratios of water, acetic acid and Cu to titanium tetraisopropoxide. The optimum preparation parameters of photocatalyst was obtained at molar ratios of water, acetic acid and Cu to titanium tetraisopropoxide of 32, 4.9, and 5.9, respectively. Physical and photoelectrochemical characterization revealed that low content of water and Cu decreased the charge transfer resistance and charge carrier recombination rate on Cu-Ni/TiO2 surface. This is attributed to the better crystallinity and less degree of agglomeration which led to obtain optimum particle size at this condition. Maximum hydrogen production rate of 2.12 mL/cm2. h was achieved under the optimum condition using the tandem photoelectrochemical cell in the aqueous KOH and glycerol solution under visible light irradiation (λ > 400 nm).

Mass transfer modeling and maximization of hydrogen rhythmic production from genetically modified microalgae biomass

A transient mathematical model for managing microalgae derived hydrogen production as a source of renewable energy is developed for a well stirred photobioreactor. The model allows for the determination of microalgae and hydrogen mass fractions produced by the photobioreactor with respect to time. A Michaelis–Menten type expression is proposed for modeling the rate of hydrogen production, which introduces a mathematical expression to calculate the resulting effect on H2 production rate after genetically modifying the microalgae species. The so called indirect biophotolysis process was used. Therefore, a singular opportunity was identified to optimize the aerobic (t1), to anaerobic (t2), stages time ratio of the cycle for maximum H2 production rate, i.e., the process rhythm. A system thermodynamic optimization is conducted through the complete model equations to find accurately the optimal system operating rhythm for maximum hydrogen production rate, and how wild and genetically modified species compare to each other. The maxima found are sharp, showing up to a ∼60% variation in hydrogen production rate for t2,opt±1day, which highlights the importance of system operation in optimal rhythm. Therefore, the model is expected to be useful for design, control and optimization of hydrogen production as a source of renewable energy.

Optimization of Hydrogen Production by Response Surface Methodology Using γ-Irradiated Sludge as Inoculum

The temperature, initial pH, and substrate concentration on fermentative hydrogen production was optimized by the Box–Behnken design using γ-irradiated sludge as inoculum, and the fermentation process was analyzed at optimal conditions. The experimental results showed that the maximum cumulative hydrogen production was 3000 mL of H2/L of medium and the hydrogen yield was 1.81 mol of H2/mol of glucose, at 32.9 °C, with an initial pH of 7.92 and a glucose concentration of 17.0 g/L. The highest hydrogen production rate was accompanied by the exponential growth of microorganisms. The mixed cultures underwent the mixed-acid-type fermentation in the first 10 h and then changed to the acetate butyrate pathway until the end of fermentation. The hydrogen yield showed a positive relationship with acetate generation during the fermentation process.

Optimization of hydrogen production with CO2 capture by autothermal chemical-looping reforming using different bioethanol purities

Autothermal Chemical-Looping Reforming (a-CLR) is a process which allows hydrogen production avoiding the environmental penalty of CO2 emission typically produced in other processes. The major advantage of this technology is that the heat needed for syngas production is generated by the process itself. The heat necessary for the endothermic reactions is supplied by a Ni-based oxygen-carrier (OC) circulating between two reactors: the air reactor (AR), where the OC is oxidized by air, and the fuel reactor (FR), where the fuel is converted to syngas. Other important advantage is that this process also allows the production of pure N2 in the AR outlet stream. A renewable fuel such as bioethanol was chosen in this work due to their increasing worldwide production and the current excess of this fuel presented by different countries.In this work, mass and heat balances were done to determine the auto-thermal conditions that maximize H2 production, assuming that the product gas was in thermodynamic equilibrium. Three different types of bioethanol has been considered according to their ethanol purity; Dehydrated ethanol (≈100vol.%), hydrated ethanol (≈96vol.%), and diluted ethanol (≈52vol.%). It has been observed that the higher H2 production (4.62mol of H2 per mol of EtOH) has been obtained with the use of diluted ethanol and the surplus energy needed could be compensated by the energy save achieved during the purification of ethanol in the production process.

Optimization of hydrogen production by solid-state aluminum, calcium hydride, nickel, and sodium borohydride

ABSTRACTA novel solid-state aluminum-calcium hydride-nickel composite/sodium borohydride system was prepared by milling and its hydrolysis performance was characeterized. The optimized system provided 100% hydrogen yield, and the hydrogen generation rate was regulated by altering the calcium hydride concentration, nickel concentration, hydrolysis temperature, and milling time. Hydrogen generation measurements and microstructure analysis showed that improved hydrogen production was obtained by microgalvanic cell formation between nickel and aluminum, decreased grain size by milling, and improved catalytic activity of nickel deposited on the surface of aluminum hydroxide.

Optimization of Hydrogen Production from Pickle Bamboo Shoot Wastewater by Rhodopseudomonas palustris TN1

A pickle bamboo shoot is a top marketing product in the East of Thailand, especially Prachinburi province. Vinegar (acetic acid) and sea salt (NaCl) are added during pickle bamboo shoot productions to preserve the color and texture. These high acidity (pH 3-4), high salt concentration (6.0%) and dark-brown color of the pickle bamboo shoot wastewater (PBSW) lead to the difficulty for bioremediation of PBSW treatment. Rhodopseudomonas palustris TN1 was capable of surviving in 3.0% (w v -1 ) NaCl medium and produce hydrogen under anaerobic-light condition. The Aim of this study is to investigate the ability of biohydrogen production in the PBSW by TN1, the effect of initial pH (6.5, 7.0 and 7.5) and light intensities (1,000, 3,000 and 5,000 lux) were performed under anaerobic-light condition. The hydrogen content in biogas using wastewater as the medium was found to be 98.51%. The optimal condition for the highest hydrogen production was pH 7.36 and light intensity of 3,200 lux at room temperature (30±2oC) giving hydrogen 73.57±5.29 mL L -1 and dry cell weight (DCW) of 5.36±0.51 g L -1 within 96 hrs. In conclusion, TN1 can consume the PBSW as a carbon source to produce hydrogen.

Optimization of hydrogen production from organic fraction of municipal solid waste (OFMSW) dry anaerobic digestion with analysis of microbial community

Summary Effect of mixed culture bacteria (MCB) addition, initial substrate concentration to inoculum (So/Xo), carbon to nitrogen (C/N) ratio on the hydrogen production (HP) from organic fraction of municipal solid waste (OFMSW) via dry anaerobic digestion was investigated. The results showed that supplementation of OFMSW with MCB substantially improved hydrogen yield (HY) and HP. HYs were 306.2 ± 33.0, 149.8 ± 16.6, and 155.3 ± 22.9 mlH2/gCODremoved for OFMSW supplemented with MCB, OFMSW, and MCB, respectively. HP at So/Xo ratio of 9.2 gCOD/gVSS was 3.1 times higher than those obtained at So/Xo ratio of 1.7 gCOD/gVSS. The maximum HY of 338.4 ± 18.9 mlH2/gCODremoved was achieved at So/Xo ratio of 9.2 gCOD/gVSS. The HP and HY were substantially increased from 169.7 ± 17.1 to 524.2 ± 34.4 ml and from 163.1 ± 23.6 to 338.4 ± 18.9 mlH2/gCODremoved with increasing the C/N from 16 to 25, respectively. However, HP and HY decreased at C/N ratio exceeding 26.6. The modified Gompertz equation model was highly fitted to the experimental data with correlation coefficient (R2 > 0.984). The 16S rRNA sequences showed the dominance of Pseudomonas fulva with similarity of 99%. Copyright © 2015 John Wiley & Sons, Ltd.

Optimisation of hydrogen production by steam reforming of chars derived from lumber and agricultural residues

The aim of this study was to develop a process to produce hydrogen-rich gas at temperatures between 650 and 700 °C, by steam reforming of char produced in a pyrolysis reactor. To achieve this, the experimental work was divided into three sections all of which primarily focus on the production of hydrogen by steam reforming. The first section investigated the impact of different chars, produced from different biomasses, and the second and third considered the effects of temperature and residence time on gas composition and yield. Feedstocks selected for this study included apple pomace, birch sawdust, coffee husk, corn cobs, dried distilled grains, hemp seeds, sugar cane and tobacco stalks. It was found that hydrogen yield, calculated as a mass percentage of biomass processed, was highest for chars produced from hemp seeds, tobacco stalk, corn cobs and coffee husk and lowest for apple pomace and sugar cane. A relationship has been derived between char yield and production of hydrogen, especially in the case of hemp seeds. Consequently, a trend was discovered (R2 = 0.90) when comparing the ash free char yield with the carbon content of the feedstock, which is useful to estimate char yields on an ash free basis if the carbon content is known. An inverse relationship was observed, for tobacco stalk, between the quantity of hydrogen produced and its purity, represented as a mole percentage of hydrogen in the gas stream, for the three different steam reforming temperatures (650, 675 & 700 °C). The residence time investigation showed that decreasing the vapour residence time, reduced both hydrogen production and purity, possibly as a result of the water gas shift reaction.