Hydrogen-rich Syngas Production Research Articles

Experiments, kinetics and DFT analysis on a novel system of biochar-oil-water slurry based hydrogen-rich syngas production via two-stage pyrolysis-reforming

Experiments, kinetics and DFT analysis on a novel system of biochar-oil-water slurry based hydrogen-rich syngas production via two-stage pyrolysis-reforming

Hydrogen-Rich Syngas Production from Waste Textile Gasification Coupling with Catalytic Reforming under Steam Atmosphere

Hydrogen-Rich Syngas Production from Waste Textile Gasification Coupling with Catalytic Reforming under Steam Atmosphere

Characteristics of solar to hydrogen-rich fuel production integrating parabolic trough collectors with partially rotatable tracking strategies

To achieve carbon neutrality, hydrogen and solar energy are receiving increasing attention. Concentrated solar thermal energy by parabolic trough collectors can be used to drive methanol cracking reactions for distributed hydrogen-rich syngas production. In this scenario, the collector is characterized by its small size and easy to integrate with hydrogen utilization equipment. However, parabolic trough collectors use a single-axis strategy with inherent large cosine loss, resulting in a low annual efficiency. The partially rotatable tracking is an advanced tracking strategy, which considers the trade-off between performance and cost compared to double-axis tracking strategies, and shows great potential for applications in distributed solar thermochemical reactions. In this study, solar to hydrogen-rich fuel production integrating parabolic trough collectors with the partially rotatable tracking strategy is proposed. The effect of the partially rotatable tracking strategy on the solar thermochemical conversion of methanol cracking is revealed. An annual normalized optical improvement of 40%∼54% is realized over a latitude range of 0∼50° by means of an optimal daily rotation angle. The solar thermochemical reactor with the partially rotatable tracking strategy has the less irreversibility loss during the concentrating process and the higher thermochemical efficiency. The results show that in three Chinese cities (Beijing, Lhasa and Guangzhou) with different latitudes and irradiation conditions, a partial north-south rotation strategy yields an additional 17.42%, 11.62% and 6.22% of chemical energy per year from the sun, while a partial east-west rotation strategy yields an additional 14.91%, 19.35% and 15.37% per year from the sun. The encouraging results indicate a promising method for the effective conversion of solar energy to chemical energy of hydrogen-rich fuels.

Simulation of thermodynamic systems in calcium-based chemical looping gasification of municipal solid waste for hydrogen-rich syngas production

This study explores calcium-based chemical looping gasification (CLG) as a method for managing municipal solid waste (MSW), with a focus on converting MSW into hydrogen-rich syngas. The innovative CS-MgO-ZrO2 calcium-based sorbent has been identified as optimal, facilitating fluidization crucial for operational stability and economic feasibility. Key discoveries include heightened H2 concentration and CO2 capture efficiency under specific operational parameters (4000 kg/h solid flow rate, 6000 kg/h steam flow rate), despite diminished H2 production at carbon conversion rates (≥0.80). Below 0.38 carbon conversion rates, a syngas injection ratio of 0.18, and oxygen flow rates >1200 kg/h induce spontaneous reactor heating, compromising efficiency and escalating costs. Furthermore, utilizing syngas in the regenerator ensures self-sufficiency and supplementary thermal energy, thereby reducing dependence on external energy sources. This research addresses critical deficiencies in waste-to-energy technologies, emphasizing potential strides in sustainable municipal waste management and energy generation.

Analysis of the effects of Pr1-xCexCoO3/dolomite catalyst on energy saving and carbon reduction in biomass gasification for the production of hydrogen-rich syngas

Biomass is considered a renewable green coal, and its clean and efficient utilization is of great significance for energy conservation and carbon reduction. One of the most critical aspects of biomass gasification is the selection of an appropriate catalyst. In this study, we synthesized a catalyst with 10 % Pr1-xCexCoO3 supported on dolomite using the sol-gel method. We conducted graded internal circulation gasification experiments to produce hydrogen-rich syngas. The effects of element substitution in PrCoO3, temperature, catalyst composition, and steam injection rate on the products were investigated. The optimal gasification conditions were determined through response surface regression analysis. The data indicate that this catalyst can improve gasification efficiency, with Pr0.4Ce0.6CoO3/Dol showing the best catalytic performance. It effectively reduces the required gasification temperature and steam amount, decreases CO2 production, and increases CO and H2 yields. The catalyst accelerates the cleavage and ring-opening reactions of hydrocarbons, leading to terminal chain hydroxylation, followed by the dehydration-condensation of methyl groups into ethers. As the temperature rises, the rate of carboxyl group removal gradually exceeds the rate of carboxyl group formation via the oxidation of hydroxyl and ether chains, resulting in an initial increase and then a decrease in the number of carboxyl groups. Under optimal gasification conditions, CO2 production is reduced by one-fourth compared to using a dolomite catalyst.

Oxygen blown steam gasification of different kinds of lignocellulosic biomass for the production of hydrogen-rich syngas

In this study, the gasification performance of different kinds of lignocellulosic biomass, including corn straw (CS), soybean straw (SS), cotton straw (CTS), rice straw (RS), wheat straw (WS), bamboo wood (BW), maple sawdust (MS), and pine sawdust (PS), was studied in a tube furnace reactor system under identical conditions (temperature = 800 °C, oxygen flow rate = 30 mL/min, steam flow rate = 5 ± 1 mL/min, and time = 55 min). SS showed good gasification characteristics and delivered the highest H2 yield of 28.96 mol/kg. By using the SS, additional optimization was carried out by considering different temperatures (650, 700, 750, 850, 950, and 1050 °C) and different oxygen flow rates (10, 20, 30, 40, and 50 mL/min). After optimization, the initial temperature and oxygen concentration were reduced to 750 °C and 10 mL/min, respectively. An H2 yield of 30.86 mol/kg was achieved with an increase of 6.56 %. Finally, catalytic steam gasification employing three potassium-based catalysts, KCl, KOH, and K2CO3, was tested using SS. KOH and K2CO3 performed distinctly better than KCl. The utilization of KOH as a catalyst resulted in the greatest H2 yield, measuring 39.22 mol/kg, which represents a notable improvement of 27.09 %.

Autothermal downdraft oxy-steam co-gasification of biomass and plastic wastes for hydrogen-rich syngas production: An Aspen plus modelling

The potential of H2-rich syngas generation using downdraft co-gasification of biomass and plastic wastes is investigated using an autothermal restricted equilibrium study using Aspen Plus. A comprehensive sensitivity analysis is carried out to impart the influence of important process parameters, viz. equivalence ratio(ER: 0.1–0.5), feed plastic content(FPC: 0–30 %), steam to feed ratio(SFR: 0–4) and steam temperature(150–1000 °C) on performance parameters, viz. syngas composition, gasification temperature(GT), lower heating value(LHV), cold gas efficiency(CGE), gasification energy efficiency(GEE) and hydrogen energy efficiency(HEE). The ER and SFR showed dominant effects on performance. The increase in ER from 0.1 to 0.5 causes an increase in GT from 565 °C to 1734 °C. The highest syngas H2 content and HEE of 52.1 % and 36.9 %, respectively, are obtained for 0.25 ER. The increase in SFR improves the syngas H2 content at the cost of LHV and GEE, with the highest HEE of 36.9 % obtained at 0.25 ER. The analysis of variance(ANOVA) and response surface methodology(RSM) has also been studied along with the multi-objective optimisation(MOO).

Comparative analysis of hydrogen-rich syngas production from various feedstocks using bubbling fluidized bed

Any carbon-based materials, including any trash that contains carbon, may be converted into sustainable energy through the thermochemical process known as gasification. The bubbling fluidized bed (BFB) is used for sewage sludge (SS), plastic waste (PW), and refuse-derived fuel (RDF) gasification. The sensitivity analysis of gasification processes is examined. The maximum H2 selectivity in RDF gasification is 70 %, followed by SS (65 %) and PW (62 %) at S/B=2. PW gasification, although producing more H2, generates more CO and CO2 than RDF and SS because to its high carbon content. At 700°C–800°C, three feedstocks have good H2 selectivity. RDF gasification has the best selectivity of all component products over the temperature range. The H2/CO molar ratio range (1–2) for chemical synthesis suggests steam to biomass (S/B) values of 1.2–2.6 for RDF and SS. As S/B value increases, CO/CO2 molar ratio increases, which compresses CO2 for CO production, improving syngas quality, notably for power generation. In PW gasification, the H2/CO ratio (≤2) is expected at >750°C. Pressure only effects H2/CO and CO/CO2, in PW gasification. The evaluation of lower heating value (LHV) and cold gas efficiency (CGE) involves exploring a range of selected parameters. Elevated reaction temperatures positively influence both LHV and CGE; however, this is not the case for S/B ratio and reaction pressure. Among the gasification processes, PW gasification exhibits the highest LHV, while SS gasification demonstrates the highest CGE. Besides, the gasification efficiency (ƞG) is found about 35–41 % at the S/B=2, which is lower than the efficiency in terms of CGE (57.6 %) due to the energy consumption increase as the temperature increased. O2/S increases negatively affect product composition but allow parameter indicator value adjustment to parameter indicator of the desired syngas product quality.

Experimental investigation on hydrogen-rich syngas production via gasification of common wood pellet in Bangladesh: Optimization, mathematical modeling, and techno-econo-environmental feasibility studies

Experimental investigation on hydrogen-rich syngas production via gasification of common wood pellet in Bangladesh: Optimization, mathematical modeling, and techno-econo-environmental feasibility studies

The utilization of metal-organic frameworks (MOFs) derived nickel-alumina catalyst for the production of hydrogen-rich syn-gas via methane tri-reforming: An innovative approach for attaining enhanced stability

Methane tri-reforming (MTR) is an innovative approach for the utilization of flue gases. In this study, a new nickel-alumina-based catalyst derived from metal-organic frameworks (MOFs) precursors is developed and tested for MTR. The activity was tested in a packed bed reactor at 600–800 °C and atmospheric pressure. The surface area of MOFs was very high (910 m2. g−1), and the porosity was <2 nm. After calcination, the porosity increased to 5–25 nm. The high surface area and the meso-porosity enhanced the dispersion and active surface area. The various reaction parameters were fine-tuned for optimal performance in MTR. RNAlM-53 catalyst displayed very high CO2 (37.5%) and CH4 (>98%) conversion at 800 °C with a constant H2/CO ratio of 3.2. The catalyst was stable for 100 h without sintering, re-oxidation, and carbon deposition. The calcination process played a pivotal role to control the catalyst porosity which improved the activity by creating new surfaces.

Microwave-assisted catalytic gasification of mixed plastics and corn stover for low tar, hydrogen-rich syngas production

The challenge for efficient management of post-consumer plastic and biomass waste has grown over the past few decades due to their dramatic increases. In comparison to conventional gasification, microwave-assisted co-gasification of plastics and corn stover offers many benefits, including increased H2 yield and gas components compared to unfavorable char/tar. Nonetheless, for future commercialization of the process and ease of product separation, further reduction of the undesirable tar is necessary, which can be achieved over the catalytic route. In this work, we studied the catalytic effect of magnetite for microwave-assisted co-gasification of corn stover and plastic to make syngas with higher H2 and lower tar selectivity over non-catalytic conditions. A 1:1:1 ratio of plastic-corn stover-magnetite was used to evaluate the reaction parameters such as temperature, space velocity, heating media, and catalytic cycles under gasification conditions. In comparison with the microwave non-catalytic route, a 100% increase in the total H2 yield with 76% higher H2 production efficiency (mmol/kWh) was achieved in the presence of the magnetite catalyst, while reducing the overall tar formation from 9% to 2%. When magnetite was reduced in situ during the reaction, it coupled with microwave and delivered oxygen radicals that cracked down plastic and corn stover intermediates generated from the synergistic effect under microwave heating. Soon after the oxygen transfer process initiated, magnetite reached its final oxidation state consisting of microwave-active Fe and Fe3C phases that continued coupling with microwaves along with the generated graphitic carbon to maintain the heat necessary to further reduce the generated tar and make additional gaseous products, as confirmed by XRD, Raman, and TGA analyses.

Development of nickel-based bimetallic catalysts for production of hydrogen-rich syngas via supercritical water gasification of liquid residue from hydrothermal pretreatment of food waste

Hydrothermal carbonization has become increasingly prevalent in the pretreatment of food waste, leading to the generation of substantial volumes of liquid effluent. This hydrothermal liquid effluent from food waste (HLF) contains high content of organic compounds, making it challenging to treat using conventional methods. In this regard, the HLF was considered a potential source for energy production via supercritical water gasification (SCWG). This study aimed to develop effective bimetallic catalysts based on Ni/Al2O3 with four different promoters (Cu, Co, La, and Ce), and investigated their performance in the catalytic SCWG for the treatment of HLF and hydrogen production. Among the tested promoters, the Ce-Ni catalyst was considered the most suitable in terms of its highest H2 yield and H2 selectivity. The optimal Ce content was found to be 5 wt%, with a catalyst dosage of 5 % by weight of HLF. These conditions resulted in the highest H2 selectivity of 1.61 and a relatively high H2 yield of 749.60 mmol/L under SCWG operating conditions of 480 °C and 30 min. Excessive catalyst dosages increased total syngas yield but reduced H2 selectivity. The stability test demonstrated that the Ce promoter contributed to enhancing the catalyst resistance to deactivation by coke deposition. The hydrogen production of 5Ce-Ni decreased by 13.8 % after three reuses, whereas a larger decrease of 26.0 % was observed with Ni/Al2O3. These findings indicate that Ce-Ni catalyst show promise for enhancing H2-rich syngas production in the SCWG of hydrothermal liquid effluent from food waste.

Response surface optimization of hydrogen-rich syngas production by methane dry reforming over bimetallic Mn-Ni/La2O3 catalyst in a fixed bed reactor

The present work utilizes a response surface optimization technique to optimize hydrogen-rich syngas production through the process of methane dry reforming (DRM). This optimization is achieved by employing a bimetallic Mn–Ni/La2O3 catalyst. The study aimed to evaluate the impact of three key parameters, namely reaction temperature, time on stream (TOS), and gas hourly space velocity (GHSV), on the hydrogen to carbon monoxide (H2/CO) ratio in syngas during the DRM. The Mn–Ni/La2O3 catalyst, synthesized using the sequential wet impregnation technique, exhibited suitable physicochemical properties necessary for DRM reaction, as evidenced by the obtained characterization data. Among the five models examined, it was found that the quadratic versus 2FI model substantially fit the experimental data, as evidenced by a p-value <0.05. The analysis of variance (ANOVA) conducted on the quadratic response surface model compared to the 2FI model demonstrated that both the reaction temperature and the TOS had a significant impact on the H2/CO ratio in the syngas. The only significant interaction factor was the relationship between the reaction temperature and the TOS. Under the specified optimal circumstances of 15 000 ml/g.h, 850 °C, and 258.15 min, an H2/CO ratio of 0.98 was achieved. The resulting H2/CO ratio of 0.98 is almost 1, indicating its suitability as a feedstock for methanol production in the Fischer-Tropsch synthesis (FTS).

Microwave-Assisted dry reforming of toluene as a model tar compound using low-cost iron catalyst for syngas clean-up

Gasification of waste feedstock such as biomass, waste plastics suffers from high tar yields during hydrogen-rich syngas production. The presence of tars result in lower quality syngas, lower syngas yields, reactor blockage, reactor down time, and costly maintenance. Therefore, removal of tar from syngas during gasification is essential. Catalytic reforming of tars via in-situ syngas cleanup is an effective way of mitigating tars. This work explores the possibility of microwave-assisted catalytic dry reforming of tars for syngas production. Due to its chemical complexity, toluene, which is one of the main tar constituents, could be used as a model tar compound. Toluene dry reforming was studied using the Fe/Al2O3 catalyst under CO2 under the temperature range of 400–700 ℃. The toluene reforming reaction was conducted using microwave and conventional thermal reactors. Under microwave irradiation, CO2 and toluene conversions are boosted to 80% at 500 ℃. Hydrogen and carbon monoxide yields were approximately five times and ten times higher in the microwave reactor at 500 ℃, respectively, compared to the productions obtained in the conventional fixed-bed reactor at 700 ℃. Filamentous carbon was also produced as a valuable side product to improve the economy of this process and such value-added carbon was only observed in the microwave reactor. Three reaction pathways were observed during microwave reaction: the toluene decomposition produces an initial hydrogen and carbon deposit on the catalyst; the formation of methane and benzene suggests toluene hydrodemethylation as a secondary reaction; and toluene hydrogenolysis forms light alkanes such as methane, and through reforming reaction under CO2 to syngas.

Highly dispersed nickel-tuned silica lanthana catalyst: Interplay of morphology and textural properties for hydrogen-rich syngas through the carbon dioxide reforming of methane

Methane (CH4) and carbon dioxide (CO2) are major contributors to the rise in greenhouse gas emissions, exacerbating global warming. Consequently, it is crucial to convert and utilize these gases effectively to mitigate their impact on the atmosphere. Carbon dioxide (dry) reforming of methane (DRM) offers an efficient solution for converting CH4 and CO2 into syngas (H2/CO). In this study, we compare the effectiveness of a robust catalytic system, including a fibrous silica lanthana-supported nickel (NSLF-10) catalyst, to a silica lanthana-supported nickel composite (NSL-C) developed using commercial lanthana and silica. Our investigation focuses on their respective performances in the production of hydrogen-rich syngas through DRM. The NSLF-10 catalyst exhibited improved physicochemical properties such as uniformly dispersed nickel, stronger metal-support interaction, small nickel particle size, and increased surface area, which significantly enhanced the catalytic performance of DRM. Notably, the NSLF-10 catalyst achieved a high conversion of CH4 and CO2 at 85 % and 83 %, respectively, with an elevated H2/CO ratio compared to the NSL-C catalyst, which has a conversion of CH4 and CO2 at 72 % and 64 %, respectively. The unique properties of the NSLF-10 catalyst provide a high synergistic effect between the nickel active sites and SLF support, leading to a high conversion of CH4 and CO2 with no signs of catalytic deactivation.

Hydrogen rich syngas production through sewage sludge pyrolysis: A comprehensive experimental investigation and performance optimisation using statistical analysis

Bioenergy is anticipated to play a significant role in the United Kingdom’s Net Zero 2050 scenario. This study aims to explore the possibility of producing hydrogen-rich syngas using sewage sludge from a wastewater treatment plant located in England, United Kingdom. The primary objective of this study is to experimentally produce hydrogen-rich syngas from sewage sludge through pre-treatment, drying, and pyrolysis. Furthermore, statistical methods have been employed to optimise the performance of the pyrolyser. The individual desirability scores for lower heating value (LHV) and cold gas efficiency (CGE) were estimated to be 0.83902 and 0.85307, respectively. Combining these scores, the overall desirability of the model reached 0.8460, indicating favourable predictive performance. The optimal operational conditions are reported to be a feed rate of 3.0488 revolutions per minute (rpm) and an operational temperature of 800°C. Under these conditions, the highest calculated CGE of 66.31% and the peak LHV value of 18.36 MJ/ m^3 were achieved.

Optimizing Hydrogen-Rich Biofuel Production: Syngas Generation from Wood Chips and Corn Cobs

This study investigates gasification using wood chips (WC) and corn cobs (CC) for hydrogen-rich syngas production. A simulation model developed in Aspen Plus was used to evaluate the performance of biomass gasification. The model incorporates a system of Fortran subroutines that automate the definition of input parameters based on the analysis of biomass composition. Furthermore, the model’s equilibrium constants were adjusted based on experimentally measured gas concentrations, increasing the precision of the variations. The numerical results predicted hydrogen yields of 65–120 g/kg biomass, with 60–70% energy efficiency for steam gasification (versus 40–50% for air gasification). The hydrogen concentration ranged from 34% to 40%, with CO (27–11%), CO2 (9–20%), and CH4 (&lt;4%). The gasification temperature increased hydrogen production by up to 40% but also increased CO2 emissions by up to 20%. Higher biomass moisture content promoted hydrogen production by up to 15% but reduced energy efficiency by up to 10% if excessive. Steam gasification with wood chips and corn cobs shows promising potential for hydrogen-rich syngas production, offering benefits such as reduced emissions (up to 30% less CO) and sustainability by utilizing agricultural residues.

Performance evaluation of carbon-negative syngas production via chemical looping reforming of methane from biomass pyrolysis volatiles

To realize the clean and efficient directional conversion of biomass, chemical looping reforming of biomass volatile CH4 based on a decoupling strategy is expected to carry out carbon-negative production of hydrogen-rich syngas. In this paper, a multi-functional oxygen carrier (NiFe2O4@SBA-16) for encapsulating the active metal oxide component NiFe2O4 with a three-dimensional interconnecting pore molecular sieve SBA-16 was designed. The experimental results showed that the modification strategy of composite metal oxide encapsulation improved syngas selectivity and CH4 conversion based on the fixed-bed reactor. 20 %NiFe2O4@SBA-16 showed 22.1 % CH4 conversion and 92.6 % CO selectivity under 750 °C, and it maintained good cycle stability after 15 cycles. The H2/CO ratio was effectively improved by adding part of CO2 into the feed gas, and the CH4 conversion reached over 35 %. This study provides essential data for the clean preparation of hydrogen-rich syngas from biomass and the development and design of multifunctional oxygen carriers.

Hydrogen-rich syngas production via steam reforming of acetic acid as bio-oil model compound: Effect of CaO addition to NiAl2O4 catalyst

Bio-oil by-products are inevitable with biomass gasification. It is considered a potential resource for hydrogen production via steam reforming. This study investigated acetic acid as a bio-model compound using a NiAl2O4 catalyst. The effect of reaction conditions on hydrogen-rich production has also been discussed, including reaction time (1 h, 3 h, 5 h and 7 h), steam/carbon ratio (S/C = 1–4) and the blend of NiAl2O4 and CaO (1:0, 3:1, 1:1, 1:3 and 0:1). The fresh and spent samples were characterized by XRD, XPS, SEM, BET, etc. The result showed that the CaO addition has several advantages: 1) it increases hydrogen gas purification; 2) it prevents Ni separation from NiAl2O4; 3) it decreases the sintering of NiAl2O4. However, Ca5Al6O14 formation decreases the activity of hydrogen production. In reaction conditions, steam is an essential factor for hydrogen gas production. The S/C ratio = 3 shows the optimum result for hydrogen gas production. Although the higher S/C ratio = 4 can maintain the adsorption activity of CaO, it causes Ni separation from NiAl2O4. The blend of NiAl2O4 and CaO is another essential factor for hydrogen gas production. Adding CaO has increased hydrogen gas production significantly. However, a little CaO in a blend ratio 3:1 does not maintain the stability of the NiAl2O4 structure. In the end, the optimum conditions are S/C ratio = 3 and blend = 1:1 at 650 °C, which produces hydrogen gas yield (2.1 mol/mol) and H2/CO (5.83).

Waste derived ash as catalysts for the pyrolysis-catalytic steam reforming of waste plastics for hydrogen-rich syngas production

Ash derived from the oxidation of waste tire and processed municipal solid waste in the form of refuse-derived fuel have been investigated for their potential as catalysts in the pyrolysis catalytic steam reforming of high-density polyethylene to produce hydrogen-rich syngas. The surface morphology, element distribution, pore structure and metal composition of the ashes were characterized to explore the effects of these ash properties on the catalytic process. Further work using tire ash investigated the influence of the process parameters, catalytic temperature and catalyst plastic ratio in relation to the production of hydrogen and syngas. The results showed that tire ash had a higher specific surface area and pore volume than refuse-derived fuel ash, resulting in a slightly higher hydrogen yield compared to refuse derived fuel ash. An increase in the temperature of the catalytic steam reforming process with the tire ash catalyst significantly increased the hydrogen yield from 13.3 mmol g−1plastic at 800 °C to 83.2 mmol g−1plastic at 1000 °C. At higher catalyst:plastic ratios, the higher amounts of catalyst produced no discernable increase in hydrogen. A tentative reaction mechanism in relation to waste derived ash as catalysts for the steam reforming of plastics pyrolysis volatiles is provided.