Highest Hydrogen Yield Research Articles

Thermodynamic assessment of hydrothermal combustion assisted fossil fuel in-situ gasification in the context of sustainable development

Developing countries cannot get rid of the fate of relying on fossil energy development in the short term, so the low-carbon transformation must be carried out in the development process to achieve the goal of net zero emissions. This work proposed a novel hydrothermal combustion assisted fossil fuel in-situ gasification (HC-ISG) system combining renewable energy, supercritical hydrothermal combustion technology and supercritical water gasification technology. The system has the advantages of high thermal efficiency, high hydrogen yield, carbon dioxide utilization and storage, and landfill of hazardous waste. Firstly, based on the concept of energy grade, the effects of renewable energy and auxiliary fuel on the characteristics of energy grade change in HC-ISG system is studied. Then, the Gibbs free energy minimization method is conducted to discuss the effects of fossil fuels, oxidants, sub- and supercritical water on the key parameters of the system. The results indicated that for HC-ISG system, the energy grade and input amount of renewable energy have the optimal values. Compared with coke and methane, the system with methanol as an auxiliary fuel for hydrothermal combustion owned better the matching between energy quantity and energy grade. Moreover, increasing the reaction temperature could reduce the exergy destruction of the system and increase the energy grade change of the input energy. When the combustion coefficient was 0.2–0.3, the molar fraction of H2 reached the maximum value. When fossil fuel with high carbon content was used, the maximum H2 yield could reach 89.4 mol/kg, and the carbon emission was 3.9 kg CO2/kg H2, so the HC-ISG system could produce clean hydrogen. The system proposed in this study may provide a promising method for efficient and low-carbon in-situ conversion of fossil energy to hydrogen production.

Insight into the thermal conversion of corn stalk gasification in supercritical water based on reactive molecular dynamics simulations

Supercritical water gasification (SCWG) technology could be used for the clean and efficient utilization of waste biomass. This work first constructed a three-dimensional macromolecular model based on the characteristics of real corn stalks (CS). The reactive force field molecular dynamics (ReaxFF MD) method was then employed to study the gasification process in supercritical water. The depolymerization process of CS in SCW was observed by tracing the evolution of the carbon-containing products during the reaction. Temperature and water concentration effects on the SCWG of CS were analyzed. The results indicated that higher temperature caused more water to decompose into hydrogen and hydroxyl radicals. Meanwhile, the large number of reactive radicals favored the production of gases such as HCHO, CH4, CO, and H2. In addition, HCHO, CH4, and CO2 would continue to hydrolyze or decompose at high temperature to produce small molecule gases such as CO and H2. Furthermore, water-gas conversion and steam-reforming reactions would occur more frequently when the water concentration was higher. As a result, higher gasification rates and higher hydrogen yields were achieved.

A circular approach for the treatment of aqueous metal effluent and biomass to generate superparamagnetic nanometal carbon hybrid and hydrogen-rich gas mixture

In this study, simulated water effluent of transition metals (Ni, Zn, Fe, and Cu) and pine needles were integrated and treated hydrothermally for the generation of hydrogen and superparamagnetic carbon hybrid of metal/metal oxides of nano-size in a single-step. The temperature plays a significant role and decides the product yield and the same was varied (300-600 °C) to optimize the product yield. The highest yield of hydrogen was obtained with nickel metal effluent, 17.2 mmol. gram−1 of pine needles at 600 °C followed by other metals i.e., Fe(11.3 mmol.gram−1), Cu (10.64 mmol.gram−1), and Zn (8.86 mmol.gram−1) and greater than 99 % of the heavy metals (HMs) has been recovered from effluents (Ni, Zn, Fe, and Cu) in the form of nanometal carbon hybrid. The synthesized nanometal carbon hybrids were analyzed with the help of X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), which shows that the metals present in the effluent get transferred to the lignocellulosic matrix of biomass during the supercritical water gasification (SCWG) that eventually gets reduced to pure metal (M(o)) from metal oxide (M(+n)). Metal oxide reduction results in the release of active oxygen, which promote the decomposition of the organics of biomass. Furthermore, the in-situ generated pure metal (M(o)) catalyzes the steam reforming and water gas shift reaction (WGS). Moreover, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM) indicate that synthesized nanometal carbon nanometal hybrid was quasi-spherical or cubical has a size less than <30 nm and are superparamagnetic material.

Enhanced pre-sensitization in metal-free covalent organic frameworks promoting hydrogen peroxide photosynthesis

Pre-sensitization caused by the intersystem crossing (ISC) of the photosensitizers for selective generation of singlet state oxygen (1O2) plays a crucial role in 2-electron O2 photoreduction toward high-yield hydrogen peroxide (H2O2), which has long been ignored. Here, the metal-free, crystalline imine-linked triazine covalent organic frameworks with cyano group-substituted (CN-COF) or non-substituted (H-COF) edge units have been developed to regulate the pre-sensitization. The incorporation of cyano group endowed CN-COF with a strong D-π-A structure, which caused a broad visible-light responsive absorption and dramatically increased charge separation, while providing highly stable photogenerated electrons. Such collaborative effect facilitated the ISC process from singlet to triplet excited states, which enabled the activation of O2 from ·O2− (H-COF) to 1O2 (CN-COF) under visible light irradiation, resulting in significantly improved activity and selectivity for H2O2 production. The CN-COF exhibited a high H2O2 yield rate of 2623 μmol h−1 g−1, and a remarkable apparent quantum efficiency of 9.8 % at 420 nm with an excellent selectivity of 94 %. This work suggests a promising cyanation approach to enhance the photosensitization of O2 to 1O2 based on metal-free organic semiconductors toward efficient O2-to-H2O2 photosynthesis.

An energy-efficient plasma methane pyrolysis process for high yields of carbon black and hydrogen

A novel thermal plasma process was developed, which enables economically viable commercial-scale hydrogen and carbon black production. Key aspects of this process are detailed in this work. Selectivity and yield of both solid, high-value carbon and gaseous hydrogen are given particular attention. For the first time, technical viability is demonstrated through lab scale reactor data which indicate methane feedstock conversions of >99%, hydrogen selectivity of >95%, solid recovery of >90%, and the ability to produce carbon particles of varying crystallinity having the potential to replace traditional furnace carbon black. The energy intensity of this process was established based on real-time operation data from the first commercial plant utilizing this process. In its current stage, this technology uses around 25 kWh per kg of H2 produced, much less than water electrolysis which requires approximately 60 kWh per kg of H2 produced. This energy intensity is expected to be reduced to 18–20 kWh per kg of hydrogen with improved heat recovery and energy optimization.

Facile integration of core–shell catalyst and Pd-Ag membrane for hydrogen production from low-temperature dry reforming of methane

Dry reforming of methane (DRM) is an important way of conversion of CH4 and CO2, two greenhouse gases, for the production of hydrogen. In this study, a catalytic membrane reactor combining an ultra-thin Pd-Ag alloy membrane with a coke-resistant Ni-SiO2@CeO2 core–shell catalyst was developed for high yield hydrogen production from DRM. The performance of membrane in the presence of gases such as CO, CO2 and CH4 was evaluated, and very little reduction in H2 flux (∼2.5 %) was observed in the presence of these gases at the relevant reaction conditions. The catalyst was tested for DRM reaction in both fixed bed reactor (FBR) and catalytic membrane reactor (CMR) to evaluate its performance at different reaction conditions. In a catalytic membrane reactor, the removal of hydrogen resulted in 1.5 times higher methane conversion compared to the calculated conversion at thermodynamic equilibrium at the used reaction conditions when hydrogen is not removed from the reaction mixture. Around 70 % of the produced H2 was recovered from the reaction stream, by virtue of the high H2 flux through the ultra-thin Pd-Ag membrane. Further, the competing reverse water gas shift reaction, that consumes the produced H2, was drastically suppressed by using membrane reactor. The suppression of reverse water gas shift reaction (RWGS) in CMR was confirmed by analyzing downstream gases using gas chromatography mass spectrometer, the result showed significantly lower H2O content for CMR than FBR. Thus, the coupling of ultra-thin membrane with a core shell catalyst synergistically improved the performance of the dry reforming of methane.

Ethanol partial oxidative reforming in gliding arc discharge plasma: A better understanding by a kinetic model study

• Ethanol POR in a GAD plasma reactor was studied through experiments and modeling. • A 0-D model was found for elaborating main pathways of reaction processes. • Results of the model were close to experiment results, with the maximum error 8.6%. • Detailed pathways of main products and ethanol were analyzed based on the results. Ethanol plasma partial oxidative reforming process was investigated through experiments and modeling in a gliding arc discharge (GAD) plasma reactor. The effect of oxygen to ethanol (O 2 /EtOH) molar ratio, flux and input power were evaluated according to yields of main products. The highest yields of hydrogen and carbon monoxide are 38.6% and 55.4%, respectively. The excited-state species including C 2 (A 3 Π g -X 3 Π u ), the C 2 Swan band and the second positive system (SPS) of nitrogen were detected by optical emission spectroscopy (OES). A zero-dimension (0-D) model of ethanol plasma partial oxidative reforming containing 457 reactions was established for describing the pathways of reforming processes and calculated by Chemkin-PRO. The detailed pathways of ethanol dissociation and production of hydrogen, carbon monoxide, methane and carbon dioxide were sorted according to the calculation result of Chemkin-PRO. The frame mechanism of ethanol plasma partial oxidative reforming showed the main pathways in the reforming processes.

Bioelectrochemical extraction of ammonium from low-strength wastewater with concomitant generation of high-purity hydrogen

Bioelectrochemical systems (BES) are emerging environmental biotechnology for recovering ammonia from waste streams. It has been tested extensively for treating ammonium-rich wastewater. This study examined the suitability of BES to facilitate carbon removal and ammonium extraction from a low ammonium liquor (3.7 mM) that mimics municipal wastewater, and concomitant production of high-purity hydrogen gas, which could potentially be harnessed as a fuel or internally recycled for ammonia stripping. Results showed that a two-chamber cation exchange membrane-equipped BES enabled a high hydrogen yield (22.8 m3 H2 m-3 d-1; >98% cathodic efficiency) and chemical oxygen demand (COD) removal (80%; 2.43 kg COD m-3d-1 at a hydraulic retention time of 4.4 h). However, for the treatment of wastewater the system demanded high energy (2.3 kWh kg COD-1; 152 kWh kg-1 N removed) and base for pH adjustment. The technology may be more suitable for recovering ammonium from wastewaters with molar ammonium to BOD ratio closer to the desired stoichiometric ratio of four, and for waste streams containing sufficient alkalinity or pH-buffering capacity, eliminating the need for dosing cation-bearing alkali.

Sr, Mg co-doped LaGaO3-δ supported Fe2O3 improved the water gas shift reaction with chemical looping

Fe2O3 is prospective for the chemical looping redox cycles but must contain a significant amount of inert supports to ensure high stability. The traditional inert supports (Al2O3, MgAl2O4, etc.) have a dilution effect on Fe2O3, which results in a compromised reactivity. In this work, we propose several Sr, Mg co-doped LaGaO3-δ to support Fe2O3 for chemical looping water splitting and investigated the synergy for the enhanced performance. Mechanistic study manifests that doping Sr increases the amount of oxygen vacancies, promoting the oxygen release and uptake during the redox reaction. Doping Mg mitigated the interaction between Fe2O3 and the supports, leading to much enhanced stability. Therefore, Fe2O3/La0.6Sr0.4Mg0.4Ga0.6O3-δ shows both high hydrogen yield (9.75 mmol.g−1) and peak hydrogen production rate (3.7 mmol.g−1.min−1). The performance shows only a slight decrease even after 100 cycles. The observed results can also inspire the selection and development of advanced supports to improve both the reactivity and stability of oxygen carriers.

Invisible active sites of Ni-Co alloy to toluene pyrolysis and hydrogen production at ultra-low temperature

Environmental problems caused by the utilization of fossil energy are becoming more and more serious, so now more attention has been paid to the use of renewable energy. Pyrolysis of biomass is a method that convert biomass energy into hydrogen, but this method is subject to the performance of the catalyst for the pyrolytic reaction. In this study, NiCo2O4 was synthesized by coprecipitation method and examined by microstructure and textual characterizations. The ability of NiCo2O4 to pyrolyze toluene and produce hydrogen was evaluated by temperature-programmed experiment and lifetime test. It was found that the sample could pyrolyze toluene at the concentration of 1500 ppm at 300 °C with a hydrogen production of 0.6%, suggesting toluene was completely pyrolyzed. In the longevity test, toluene can be completely pyrolyzed for at least 5 h at 400 °C, with a high hydrogen yield of above 80% maintained during the pyrolysis process. As the pyrolysis reaction progresses, NiCo2O4 was gradually reduced to nickel-cobalt alloy by hydrogen from the pyrolysis of toluene, indicating the actual active site of nickel-cobalt alloy. This study gives a hint for developing a good catalyst for the ultra-low temperature biomass pyrolysis to produce hydrogen.

Mechanism of hydrogen generation from low melting point elements (Ga, In, Sn) on aluminum alloy hydrolysis

The reaction of aluminum water to produce hydrogen is prevented by an alumina film. To prepare a kind of aluminum alloy with instant hydrogen production and high hydrogen yield, this paper investigates the effect of different Ga content and In–Sn ratio on the hydrogen production performance of aluminum alloy, and also observes the effect of hydrogen production at different temperatures. The composition, structure, and thermal properties are observed by Scanning Electron Microscope, X-ray diffraction, and differential scanning calorimetry. With different ratios of In and Sn, they appear as two intermetallic compounds, In3Sn and InSn4. When Ga, In, and Sn were added to aluminum together, the hydrolytic properties of the Al-Ga-In-Sn alloys are greatly improved. The paper finally prepared an aluminum alloy with a hydrogen conversion rate of more than 98% and activation energy of 39.2 kJ/mol. Further the development and utilization of hydrogen energy are promoted.

Simulation and design of an energy accumulator around the hydrogen energy vector

This work demonstrates the study of the numerical modelling and a design of a compact energy generator based on green hydrogen. This generator aims allowing the energy storage, electricity, cold and heat productions as well as a supply the energy for the production of the sanitary hot water. The generator is considered to be powered by 30 solar cells panels and will mainly consist of a Proton Exchange Membrane (PEM) electrolyzer compiled with a Metal Hydride (MH) tank, a PEM fuel cell, and a system of heat exchangers sized to recover the heat from the electrolyzer, PEM fuel cell and MH tank. Furthermore, the generator will contain an adsorber to manage air conditioning (cooling and heating) and a production of the sanitary hot water. A converter block is included in the generator, in particular, a Buck-booster to raise the voltage of the solar panels and the DC-AC converter for the electricity consumption in the household. The desorption of the hydrogen contained in the tank MH will take place using the heating resistance. In overall, the designed generator is foreseen to have a dimension of 1800 × 1000 × 500 mm and its role is to allow integration of the hydrogen energy for the tertiary and residential sectors. As such it is a suitable choice of components for the cost reduction and high yield hydrogen production, storage, and consumption.

Influence of key operational parameters on biohydrogen production from fruit and vegetable waste via lactate-driven dark fermentation

This study aims at investigating the influence of operational parameters on biohydrogen production from fruit-vegetable waste (FVW) via lactate-driven dark fermentation. Mesophilic batch fermentations were conducted at different pH (5.5, 6.0, 6.5, 7.0, and non-controlled), total solids (TS) contents (5, 7, and 9%) and initial cell biomass concentrations (18, 180, and 1800 mg VSS/L). Higher hydrogen yields and rates were attained with more neutral pH values and low TS concentrations, whereas higher biomass densities enabled higher production rates and avoided wide variations in hydrogen production. A marked lactate accumulation (still at neutral pH) in the fermentation broth was closely associated with hydrogen inhibition. In contrast, enhanced hydrogen productions matched with much lower lactate accumulations (even it was negligible in some fermentations) along with the acetate and butyrate co-production but not with carbohydrates removal. At pH 7, 5% TS, and 1800 mg VSS/L, 49.5 NmL-H2/g VSfed and 976.4 NmL-H2/L-h were attained.

Q-PCR Methodology for Monitoring the Thermophilic Hydrogen Producers Enriched from Elephant Dung

This study aims to create a quantitative polymerase chain reaction (q-PCR) methodology for monitoring the hydrogen-producing mixed cultures enriched from elephant dung using alpha-cellulose as a carbon source through five generations of repetitive sub-culture. The enriched thermophilic mixed cultures from the fifth cultivation cycle gave the highest hydrogen yield of 170.3 mL H2/g cellulose and were used to generate hydrogen from sawdust. Clostridium sp. and Thermoanaerobacterium sp. were the dominant bacteria in thermophilic mixed cultures with high hydrogen yield, according to polymerase chain reaction-denatured gradient gel electrophoresis (PCR-DGGE). q-PCR primers Chis150F and ClostIR, TherF and TherR, and BacdF and BacdR were developed to amplify the 16S rRNA genes of Clostridium sp., Thermoanaerobacterium sp., and Bacillus sp., respectively, for the quantification of hydrogen-producing bacteria in biohydrogen fermentation. Similar q-PCR analysis of Clostridium sp., Thermoanaerobacterium sp., and Bacillus sp. 16S rRNA gene amplification during hydrogen production from cellulose and sawdust revealed increasing gene copy number with time. The molecular approaches developed in this study can be used to monitor microbial communities in hydrogen fermentation processes efficiently.

Effect of Fe on the Hydrogen Production Properties of Al-Bi-Sn Composite Powders.

Fe additives may play an important role in the preparation of aluminum-based hydrolysis hydrogen powder, with high hydrogen yield, low cost, and good oxidation resistance. Therefore, it is necessary to ascertain the effect of Fe on the hydrogen production performance of Al-Bi-Sn composite powders. According to the calculated vertical cross-section of the Al-10Bi-7Sn-(0~6)Fe (wt.%) quasi-binary system, Al-10Bi-7Sn-xFe (x = 0, 0.5, 1.5, 3) wt.% composite powders for hydrogen production were prepared by the gas-atomization method. The results showed that the Al-10Bi-7Sn-1.5Fe (wt.%) powder exhibited an extremely fast hydrogen generation rate at 50 °C, which reached 1105 mL·g−1 in 27 min in distilled water, 1086 mL·g−1 in 15 min in 0.1 mol·L−1 NaCl solution, and 1086 mL·g−1 in 15 min in 0.1 mol·L−1 CaCl2 solution. In addition, the antioxidant properties of these powders were also investigated. The results showed that the hydrogen production performance of the Al-10Bi-7Sn-1.5Fe (wt.%) powder could retain 91% of its hydrogen production activity, even though the powder was exposed to 25 °C and 60 RH% for 72 h. The addition of Fe not only promoted the hydrogen generation rate of the Al-Bi-Sn composite powders, but also improved their oxidation resistance. The Al-10Bi-7Sn-1.5Fe (wt.%) composite powder shows great potential for mobile hydrogen source scenarios with rapid hydrogen production.

Metal boride-decorated CoNi layered double hydroxides supported on muti-walled carbon nanotubes as efficient hydrolysis catalysts for sodium borohydride

Without effective and secure hydrogen production, it is impossible to utilize hydrogen energy on a large scale. Whereas hydrogen emission from NaBH4 hydrolysis with high hydrogen yield is an impressively efficient hydrogen supply method. However, it is affected by sluggish hydrogen production kinetics and low yields, therefore it is required to develop hydrolysis catalysts with good performance under alkaline conditions. In this study, a composite of unique CoNi layered double hydroxide (CoNi-LDH) nanosheets interconnected by muti-walled carbon nanotubes (MWCNTs) was prepared for the first time, and the surface was modified with metal borides produced by in-situ reduction. Among them, CoNi-LDH nanosheets are created when CoNi-MOF spontaneously derivates in alkaline electrolytes. The successful preparation of CoB-LDH-CNT has been confirmed by SEM, TEM, EDS, XRD, and XPS characterization. The hydrolysis experiments show that it has good catalytic activity with an optimal hydrogen generation rate (HGR) of 5167.72 mL·min−1·g−1 and low activation energy (Ea) of 29.93 kJ·mol−1. After ten cycles of experiments, it still has 75.4% of the initial performance, showing excellent stability, which may be attributed to the fact that MWCNTs can help to reconnect broken nanosheets during the reaction. This interconnected multistage structure offers a new methodology for enhancing the catalytic performance of metal boride and metal hydroxide materials.

Degradation of rubber waste into hydrogen enriched syngas via microwave-induced catalytic pyrolysis

Microwave-induced catalytic pyrolysis of end-of-life tires was conducted for the purpose of producing hydrogen-enriched syngas. Tire derived char (TDC) was employed as the catalyst due to its superiorities of excellent microwave-absorbing ability, remarkable catalytic effect, and cost-effectiveness. The effects of the carbon structure, microwave power, and tire-to-catalysts ratio on the hydrogen yield and conversion rate were investigated. TDC had two functions in promoting the production of hydrogen in microwave-induced pyrolysis (MP). One was facilitating the degradation of tar into gas, and the other was initiating the catalytic reforming of light hydrocarbons into hydrogen. The highest hydrogen yield (27.81 mmol/g) and conversion rate (85.57%) were obtained under optimal experimental conditions. The as-generated TDC in MP could be reused as a catalyst for MP, thus improving the economics of this method significantly. This research provides an efficient and economical strategy for the microwave-induced pyrolysis of end-of-life tires to produce hydrogen-rich syngas.

Co–solvent effects on hydrothermal co–gasification of coal/biomass mixtures for hydrogen production

The use of low–rank coals for hydrogen production by gasification can create advantageous options to overcome a potential energy crisis. In this study, the effects of 8 different solvents on gasification and hydrogen yield in coal/biomass co–solvent hydrothermal gasification were investigated. The most effective co–solvent on product conversion and high hydrogen yield was found N–methyl pyrrolidone (NMP) and tetrahydrofuran (THF). Total gas volumes and hydrogen yields obtained from the co–solvent gasification of coal/sorghum blends were higher than the arithmetical sum of the average values of the yields from individual solvent and coal/sorghum blend gasifications. The increase in the hydrogen yield was 11 mol H2/kg feed with the co–solvent THF due to the synergistic effects of THF on hydrogen production. Solvent concentration was effective on both total gas volumes and hydrogen yields. In the catalytic (K2CO3/CaO) runs with a concentration of 20 % (v/v) NMP co–solvent 98.8 ± 0.1 mol H2/kg feed was achieved with a dramatic decrease of CO content in the produced gas mixture. The comparison of the results obtained from subcritical and supercritical water conditions showed that in catalytic processes co–solvent was more effective towards feedstock conversion and almost the same hydrogen yields obtained at lower pressures under the subcritical water conditions.

Defected tungsten disulfide decorated CdS nanorods with covalent heterointerfaces for boosted photocatalytic H2 generation

Owing to their intrinsic and pronounced charge carrier transport when facing the formidable challenge of inhibiting severe surface charge recombination, one-dimensional (1D) CdS nanostructures are promising for advancing high-yield hydrogen production. We herein demonstrate an efficient strategy of boosting interfacial carrier separation by heterostructuring 1D CdS with defective WS2. This process yields solid covalent interfaces for high flux carrier transfer that differ distinctively from those reported structures with physical contacts. As a nonnoble cocatalyst, WS2 can accept photogenerated electrons from CdS, and the sulfur vacancies existing at its edges can effectively trap electrons as active sites for H2 evolution. Moreover, due to its strong negative property, the H+ from the aqueous solution can gather around WS2. WS2 possesses a lower reaction barrier than CdS, which expedites the kinetic process for the reaction. The optimized sample exhibits a high photocatalytic H2 evolution rate of 183.4 µmol/h (10 mg photocatalyst), which is as far as we know among the top in the records for CdS-based photocatalysts. We believe this present work will be inspiring in addressing the interfacial charge carrier transfer by constructing covalent heterointerfaces.

Combined Bio-Hydrogen, Heat, and Power Production Based on Residual Biomass Gasification: Energy, Exergy, and Renewability Assessment of an Alternative Process Configuration

Bio-hydrogen from residual biomass may involve energy-intensive pre-treatments for drying and size management, as in the case of wet agro-industrial residues. This work assesses the performance of an alternative process layout for bio-hydrogen production from citrus peel gasification, with the aim of cogenerating heat and power along with hydrogen, using minimal external energy sources. The process consists of an air-steam fluidized bed reactor, a hydrogen separation unit, a hydrogen compression unit, and a combined heat and power unit fed by the off-gas of the separation unit. Process simulations were carried out to perform sensitivity analyses to understand the variation in bio-hydrogen production’s thermodynamic and environmental performance when the steam to biomass ratios (S/B) vary from 0 to 1.25 at 850 °C. In addition, energy and exergy efficiencies and the integrated renewability (IR) of bio-hydrogen production are evaluated. As main results, the analysis showed that the highest hydrogen yield is 40.1 kgH2 per mass of dry biomass at S/B = 1.25. Under these conditions, the exergy efficiency of the polygeneration system is 33%, the IR is 0.99, and the carbon footprint is −1.9 kgCO2-eq/kgH2. Negative carbon emissions and high values of the IR are observed due to the substitution of non-renewable resources operated by the cogenerated streams. The proposed system demonstrated for the first time the potential of bio-hydrogen production from citrus peel and the effects of steam flow variation on thermodynamic performance. Furthermore, the authors demonstrated how bio-hydrogen could be produced with minimal external energy input while cogenerating net heat and power by exploiting the off-gas in a cogeneration unit.