Syngas Formation Research Articles

Strategic conversion of plastic containers with food waste into energy through thermochemical processes

Plastic valorization has received particular attention as an environmentally benign approach to achieve carbon neutrality and reduce greenhouse gas emissions. However, contaminated plastic and biomass waste mixtures suffer from single-stream recycling. Waste mixtures are currently discarded through landfilling and incineration. As a sustainable disposal and valorization method for converting plastic and biomass waste mixtures into energy-intensive products, especially syngas (H2 and CO), this study utilizes catalytic pyrolysis and a CO2 flow gas. A plastic container contaminated with a food waste mixture (PFW) was used as the model waste. The major products of the pyrolysis of PFW were liquid hydrocarbons (HC) (C7–30) and wax-like HCs with negligible formation of oxygen-containing HCs. However, the high production of wax-like HCs becomes a problem. Catalytic pyrolysis was employed to convert HCs into simpler product streams such as syngas. Although syngas formation tripled with the Ni catalyst, catalyst deactivation was observed. To suppress catalyst deactivation and promote CO formation, CO2 was introduced instead of N2. During the CO2-assisted catalytic pyrolysis, the syngas yield from PFW increased to 95.5 % because the chemical reactions between CO2 and liquid/wax-like HCs produced additional H2 and CO. The catalytic reaction with CO2 suppressed carbon deposition because long-chain HCs were converted to CO rather than coke.

Thermochemical valorisation of cattle manure into gaseous fuel and furfural-rich bio-oil

Surplus carbon, in the form of carbon dioxide (CO2), has aggravated global warming over several past decades. To divert the current energy mix that relies heavily on fossil fuels, researchers have realised waste materials as alternative energy. Such attempts could reduce CO2 emissions and potentially contribute to establishing a circular economy. This study investigated the transformation of cattle manure (CM) into value-added products (syngas and furfural) via a thermochemical pathway. The CM was treated with FeCl3 prior to pyrolysis to enhance the conversion selectivity toward syngas and furfural. Slow-pyrolysis was conducted to determine the mechanisms of syngas production, and fast-pyrolysis was undertaken to optimize bio-oil production. Thermogravimetric analysis revealed that Fe impregnation facilitated the thermal degradation of CM, resulting in enhanced syngas formation. The oil product obtained from the Fe-impregnated CM exhibited notable enrichment in furfural and a much simpler chemical composition than that of the untreated CM. Furthermore, the produced biochar catalytically expedited the kinetics of the transesterification reaction of canola oil. The overall results of this study offer a practical means of converting livestock manure into useful resources, thereby contributing to the realisation of a circular economy.

Carbonate Electrolysis for Energy Efficient Direct Air Capture of CO2

Yearly global energy related CO2 emissions continue to increase, reaching a record breaking 37 billion metric tons in 2022. As a major greenhouse gas, CO2 levels need to be reduced by 10s of gigatons to prevent the worst of climate change, something that is no longer feasible with net-zero emissions alone. Removing atmospheric CO2 is therefore of critical importance for the future of our planet. While major improvements have been made in CO2 capture from large point sources, a significant portion of CO2 emitted each year from the United States comes from distributed sources such as cars and smaller factories. Due to the dilute concentrations of CO2 in ambient air, Direct Air Capture (DAC) needs to be highly selective to preferentially absorb CO2 to collect useable amounts. These challenges have made current DAC systems quite costly, both energetically and economically, and require vastly different strategies than carbon capture from concentrated sources.At Giner, we are developing a novel process for the capture and regeneration of CO2 from air into a purified, concentrated CO2 stream that can be redirected as a feedstock for a wide range of applications, including chemical manufacturing and syngas formation. This process involves the capture of CO2 in a concentrated KOH solution using a high-surface area air contactor to form potassium carbonate. The potassium carbonate is then efficiently electrolyzed in a hydrogen-assisted process to regenerate the CO2 at a low operating potential, increasing the electrical efficiency of the process while producing concentrated and purified CO2. In addition, water, hydrogen, and KOH are also regenerated as byproducts that can be recycled back into the CO2 capture and electrolysis processes, reducing both overall energy and chemical consumption.Giner has developed a unique 3-compartment carbonate electrolysis flow cell. Using our electrolyzer, we have seen operating voltage as low as 1.2 V at 100 mA/cm2 in a 5 cm2 cell for potassium carbonate conversion to CO2 with H2 assisted electrolysis. Significant improvements in operating voltage have come from optimization of gas-diffusion layers (GDLs), cell geometry, and membrane selection. Furthermore, we have achieved >97% pure CO2 formation in the internal flow-through compartment. Currently, scale-up is in progress to apply these developments to approach comparable conditions in a 50 cm2 multi-cell stack. Further developments will enable pairing with an in-house, carbonate based, air contactor allowing for capture and regeneration of over 1 ton CO2 per year. Acknowledgement: The project is financially supported by the Department of Energy's ARPA-E Office under the Grant DE-AR0001495

Unveiling the catalytic performance of unique core-fibrous shell silica-lanthanum oxide with different nickel loadings for dry reforming of methane

The dry reforming of methane (DRM) stands as a remarkable process for the conversion of methane and carbon dioxide into syngas (H2/CO). In this study, mesoporous fibrous silica lanthanum oxide-supported nickel catalysts (NSLF-x) with various nickel loadings (3 to 15 wt%) were efficiently fabricated using the microemulsion and impregnation approaches, respectively, to conduct DRM. The results obtained from FESEM and TEM revealed the presence of a unique core-fibrous shell-structured morphology of silica lanthanum oxide support (SLF). Furthermore, XRD and SEM-EDS analyses indicated that the structural integrity of SLF remained consistent regardless of the amount of Ni loading, while the size of NiO nanocrystalline varied with the quantity of Ni loading. Notably, H2-TPR analysis emphasized that the NSLF-15 catalyst exhibited the strongest metal-support interaction among the catalysts. Due to this reason, it exhibited outstanding catalytic activity and stability in terms of CO2 conversion (86.7 %), CH4 conversion (87 %), and a high H2/CO ratio at 750 °C, demonstrating high thermal stability after 28 h without any signs of deactivation. The superior catalytic performance of NSLF-15 catalysts, along with their ability to activate CH4 and CO2, can be attributed to the synergistic effects resulting from the enhanced physicochemical properties and the unique morphology. Additionally, the results from TEM, Raman, and TGA analyses also indicated the presence of non-filamentous carbon and filamentous carbons with accumulation of Ni species due to the elevated temperature of the reaction. Overall, the NSLF-15 catalysts hold significant potential for industrial-scale application for syngas formation.

Optimizing carrot pulp waste valorization via thermochemical conversion using carbon dioxide

This study proposes an environmentally sustainable approach for converting food waste into fuels and chemicals, especially focusing on syngas production. The carbon-negative aspect of the pyrolysis process was achieved by employing CO2 as the reaction medium. Carrot pulp waste (CPW) was used as an exemplary food waste in this work. In the single-stage pyrolysis of CPW, the presence of CO2 led to improved syngas generation. The introduction of CO2, rather than N2 carrier gas, resulted in substantial increase of CO formation at temperatures ≥ 400 °C, with a decrease in bio-oil production. This phenomenon was due to the chemical reactions between CO2 and the volatile organic compounds (VOCs) produced during the pyrolysis of CPW. Specifically, CO2 played a mechanistic role by providing an extra oxygen source for CO production and participating in the oxidative thermal cracking of VOCs. In-depth analysis of multi-stage pyrolysis verified the mechanistic role of CO2, particularly at temperatures ≥ 190 °C. However, CO2-induced reactions influenced the molecular size of the VOCs. To boost the CO2-induced reactions for additional syngas formation, a nickel-based catalyst was introduced during the pyrolysis of CPW, which effectively expedited the homogeneous reactions initiated by CO2, thereby indicating its potential to accelerate and optimize food waste valorization.

Thermochemical conversion of silkworm by-product into syngas

This study explored the valorisation of silkworm by-product, a major by-product of the silk industry (sericulture), which amounts to 16 million tonnes annually. The focus was on transforming waste into energy resources through pyrolysis under CO2 conditions. In one-stage pyrolysis, the evolution of syngas under N2 was found to be comparable to that under CO2. A notable allocation of carbon to biocrude rather than syngas was observed. The two-stage pyrolysis resulted in increased syngas production. However, achieving a homogeneous reaction between CO2 and the volatiles liberated from silkworm byproduct proved challenging. Indeed, the reaction kinetics governing CO2 reactivity was not fast although the temperature windows of the reaction were aligned in the two-stage pyrolysis. To address this issue, pyrolysis was performed using a Ni-based catalyst to expedite the reaction kinetics. Consequently, syngas formation, particularly CO formation, was significantly enhanced under CO2 conditions compared to that under N2 conditions. The syngas yield under CO2 was 36.42 wt% which was 2-fold higher than that of N2. This suggested the potential of CO2 altering the carbon distribution from biocrude to syngas. This strategy would contribute to the establishment of sustainable production of silk by converting sericulture by-product into energy/chemical resources.

Mechanistic study of chemical looping partial oxidation of methane over Ce2(SO4)3/MgO with CoO modification

Chemical looping partial oxidation of methane (CLPOM) to syngas provides an exceptional opportunity for methane utilization. However, it is still urgent to obtain efficient oxygen carrier (OC) and clarify its microscopic mechanism. In this work, CoO and MgO modified Ce2(SO4)3 OC are optimized based on various preparation methods and different CoO and Ce2(SO4)3 doping amount. Considering the conversion rate (XCH4), selectivities of CO (SCO) and H2 (SH2), H2/CO molar ratio, when the doping amount of CoO, Ce2(SO4)3 and MgO is 20 wt%, 30 wt% and 50 wt% respectively, the OC prepared by mechanical ball milling method has a better thermodynamic and kinetic properties in chemical looping reaction. Compared with literature, this OC has a larger XCH4. In multiple cycles, XCH4 is still higher than 90%, SCO and SH2 remain above 95%. Density functional theory calculation reveal that the Co doping reduces the energy barrier (Eb) of rate-limiting step by 24.3% and lowers the migration Eb of lattice oxygen by 78.2%. The OC with oxygen vacancy can further reduce the Eb of rate-limiting step, but the Eb basically remains unchanged when the oxygen vacancy (Ov) concentration is greater than 1.96%. Because of the high Eb of CO2 formation and low Eb of syngas formation, the syngas demonstrates high selectivity and does not produce CO2 in experiment. Meanwhile, the doping of CoO and MgO reduces carbon deposition, refines the nano-particles of OC, increases the specific surface area (SSA), and enhances resistance to sintering and aggregation. The unique pore structure also provides a favorable microenvironment for the reaction. These findings demonstrate that CoO and MgO modified Ce2(SO4)3 OC have the potential for application in CLPOM, and these basic insights can also be applied to other chemical looping systems.

Photo-thermal coupled single-atom catalysis boosting dry reforming of methane beyond thermodynamic limits over high equivalent flow

Driving dry reforming of methane (DRM) reaction by photo-thermal catalysis is a more gentle, efficient and environmentally friendly process than the traditional thermal catalysis. However, the process still lacks efficient catalyst and clear reaction mechanism. In this paper, we developed a Ru1/Mg-CeO2-NR single-atom catalyst (SAC), of which the molar fraction of syngas under photo-thermal catalysis (PTC) conditions could exceed the thermodynamic equilibrium limit of the same temperature in dark condition even at high equivalent flow rates, while achieving a molar level syngas formation rate (0.56 mol·gcat−1·h−1 for H2 and 0.85 mol·gcat−1·h−1 for CO) at only 500 °C. Besides, the electron transfer path of Ru-O-Ce and its promoting effect on RDS of DRM reaction were determined by operando experiments, and the in-depth mechanism of photo-thermal synergistic catalytic reaction was also illustrated. Finally, the superiority of the Ru1/Mg-CeO2-NR SAC configuration was investigated by density functional theory (DFT) calculation and the reversible structural evolution of Ru-O-Ce to Ru-Ov-Ce was verified, which provided the efficient and stable coordination environment for PTC-DRM reaction.

Thermal decomposition of magnesium carbonate in methane atmosphere for the synthesis of syngas: The effect of O2

Excess CO2 emissions from the conventional decomposition of carbonate process industry, have a lasting and detrimental effect on the global climate. It is a significant task to figure out how to minimize these processes' CO2 emissions from sustainable development of society. In this work, the thermal decomposition of MgCO3 in CH4 reduction environment for the formation of syngas was investigated in great depth. The addition of O2 to the thermal decomposition of MgCO3 in CH4 atmosphere reaction system reduced the reaction temperature by 300 °C and prevented the coke formation on the metal oxide (near zero carbon high quality MgO), as demonstrated by both theoretical calculations and experiments. And the formation of valuable syngas byproducts (CO/H2 =1:3) and the noteworthy reduction of CO2 emissions (with a suppressed selectivity of 15%) can be obtained through this process. This research gives a helpful and long-term strategy for cutting down on CO2 emissions in the conventional process industries (ie. carbonate decomposition) and provides a new view for valuable product (ie. syngas) synthesis.

Tunable Syngas Formation at Industrially Relevant Current Densities via CO2 Electroreduction and Hydrogen Evolution over Ni and Fe-derived Catalysts obtained via One-Step Pyrolysis of Polybenzoxazine Based Composites.

Simultaneous electroreduction of CO2 and H2O to syngas can provide a sustainable feed for established processes used to synthesize carbon-based chemicals. The synthesis of MOx/M-N-Cs (M = Ni, Fe) electrocatalysts reported via one-step pyrolysis that shows increased performance during syngas electrosynthesis at high current densities with adaptable H2/CO ratios, e.g., for the Fischer-Tropsch process. When embedded in gas diffusion electrodes (GDEs) with optimized hydrophobicity, the NiOx/Ni-N-C catalyst produces syngas (H2/CO = 0.67) at -200mA cm-2 while for the FeOx/Fe-N-C syngas production occurs at ≈-150mA cm-2. By tuning the electrocatalyst's microenvironment, stable operation for >3h at -200mA cm-2 is achieved with the NiOx/Ni-N-C GDE. Post-electrolysis characterization revealed that the restructuring of the catalyst via reduction of NiOx to metallic Ni NPs still enables stable operation of the electrode at -200mA cm-2, when embedded in an optimized microenvironment. The ionomer and additives used in the catalyst layer are important for the observed stable operation. Operando Raman measurements confirm the presence of NiOx during CO formation and indicate weak adsorption of CO on the catalyst surface.

Plasma-based dry reforming of CH4: Plasma effects vs. thermal conversion

In this work we evaluate the chemical kinetics of dry reforming of methane in warm plasmas (1000–4000 K) using modelling with a newly developed chemistry set, for a broad range of parameters (temperature, power density and CO2/CH4 ratio). We compare the model against thermodynamic equilibrium concentrations, serving as validation of the thermal chemical kinetics. Our model reveals that plasma-specific reactions (i.e., electron impact collisions) accelerate the kinetics compared to thermal conversion, rather than altering the overall kinetics pathways and intermediate products, for gas temperatures below 2000 K. For higher temperatures, the kinetics are dominated by heavy species collisions and are strictly thermal, with negligible influence of the electrons and ions on the overall kinetics. When studying the effects of different gas mixtures on the kinetics, we identify important intermediate species, side reactions and side products. The use of excess CO2 leads to H2O formation, at the expense of H2 formation, and the CO2 conversion itself is limited, only approaching full conversion near 4000 K. In contrast, full conversion of both reactants is only kinetically limited for mixtures with excess CH4, which also gives rise to the formation of C2H2, alongside syngas. Within the given parameter space, our model predicts the 30/70 ratio of CO2/CH4 to be the most optimal for syngas formation with a H2/CO ratio of 2.

Municipal solid waste gasification by hot recycling blast furnace gas coupled with in-situ decarburization to prepare blast furnace injection of hydrogen-rich gas

Waste-to-energy is one of the most effective methods to save energy and reduce carbon emissions. This paper proposes a novel process of municipal solid waste (MSW) gasification by hot recycling blast furnace gas (BFG) coupled with in-situ decarburization to prepare blast furnace injection of hydrogen-rich gas. MSW gasification by the hot BFG is conducted by using Aspen Plus software coupled with equilibrium model or kinetic model. Compared to the equilibrium model, kinetic simulation results exhibit good agreement with the experimental results. Moreover, the technological analysis is also performed to investigate the coupled effects of gasification temperature, MSW/BFG ratio, and steam/MSW ratio on the H2-rich syngas generated from MSW gasification. The results reveal that all the investigated influencing factors have been found with a significant effect on the H2-rich syngas formation. The 25.95 vol% of H2 and 37.20 vol% of CO during MSW gasification by the hot BFG are achieved at a gasification temperature of 900 °C, steam/MSW ratio of 0.46 kg/kg, and MSW/BFG ratio of 0.34 kg/Nm3.

A semiconducting hybrid of RhOx/GaN@InGaN for simultaneous activation of methane and water toward syngas by photocatalysis.

Prior to the eventual arrival of carbon neutrality, solar-driven syngas production from methane steam reforming presents a promising approach to produce transportation fuels and chemicals. Simultaneous activation of the two reactants, i.e. methane and water, with notable geometric and polar discrepancy is at the crux of this important subject yet greatly challenging. This work explores an exceptional semiconducting hybrid of RhOx/GaN@InGaN nanowires for overcoming this critical challenge to achieve efficient syngas generation from methane steam reforming by photocatalysis. By coordinating density functional theoretical calculations and microscopic characterizations, with in situ spectroscopic measurements, it is found that the multifunctional RhOx/GaN interface is effective for simultaneously activating both CH4 and H2O by stretching the C-H and O-H bonds because of its unique Lewis acid/base attribute. With the aid of energetic charge carriers, the stretched C-H and O-H bonds of reactants are favorably cleaved, resulting in the key intermediates, i.e. *CH3, *OH, and *H, to sit on Rh sites, Rh sites, and N sites, respectively. Syngas is subsequently produced via energetically favored pathway without additional energy inputs except for light. As a result, a benchmarking syngas formation rate of 8.1 mol·gcat-1·h-1 is achieved with varied H2/CO ratios from 2.4 to 0.8 under concentrated light illumination of 6.3 W·cm-2, enabling the achievement of a superior turnover number of 10,493 mol syngas per mol Rh species over 300 min of long-term operation. This work presents a promising strategy for green syngas production from methane steam reforming by utilizing unlimited solar energy.

Generation of active oxygen species by CO2 dissociation over defect-rich Ni-Pt/CeO2 catalyst for boosting methane activation in low-temperature dry reforming: Experimental and theoretical study

Herein, we demonstrated a one-pot complex combustion method to synthesize defect-rich Ni-Pt/CeO2 catalyst having oxygen vacancy sites (Vo) by incorporating Ni and Pt species into the ceria lattice. These Vo sites are highly active for dissociating CO2 into reactive oxygen species and CO at low temperature. CH4-TPSR demonstrated that surface reactive oxygen species are more selective than lattice oxygen toward the formation of syngas. The catalytic properties and activity of the synthesized catalysts were also compared with the conventionally impregnated catalyst. In-situ DRIFT and Raman study revealed reactive oxygen-assisted CH4 activation via the formation of CHxO intermediate. DFT calculation also showed the facile formation of CH3O and CH2O species over the bimetallic NiPt-CeO2(111) catalyst surface. The Ni-Pt/CeO2 (0.5 wt%Pt-2 wt%Ni) catalyst showed superior activity and stability with ∼86% conversion of CH4 and CO2 at 675 °C, where the H2/CO ratio is one. The catalyst was stable up to 700 h time-on-stream.

PdCu alloy promoting oxygen migration towards enhanced photocatalytic methane reforming with CO2 to syngas

Photocatalytic methane reforming with CO2 is a meaningful route to syngas. The sluggish mobility of oxygen during the reaction is known as a key issue that causes low activity and poor stability of catalysts due to coke formation. Herein, we report a novel PdCu-ZnO photocatalyst that is made up of PdCu alloy formed by Pd doping of Cu on ZnO nanoplates. The PdCu alloy benefits the oxygen migration process between metal and ZnO. The in situ characterizations and DFT calculations confirm the interaction between PdCu alloy and ZnO, and the process of metal alloy promoting oxygen migration during methane dry reforming has been revealed for the first time. The optimized PdCu-ZnO photocatalyst displayed a high syngas formation rate of over 15 mmol galloy-1h−1 with H2/CO = 1 and splendid stability. The “alloy promoting oxygen migration” strategy could shed light on the design of effective photocatalysts for methane dry reforming.

Sulfidation performance of unsupported and SBA 15-supported Ca-based mixed metal oxides

Coal is the most widely used fossil fuel resource, and clean coal technologies allow an increase in the efficiency of clean energy production. Gasification-based combined cycle power generation systems, for example, aim to produce a mixture of CO and H2 (syngas) formed from coal and biomass. However, H2S is an undesired gasification product of fossil fuels with their high sulfur content. Hot gas desulfurization (HGD) reduces the sulfur contents of the gasification products by eliminating thermal losses of endothermic syngas formation processes. This study aims to develop efficient sorbents to remove H2S from hot flue gas. Unsupported and SBA 15-supported Ca-based binary mixed metal oxides (CuO, FeO, MnO, ZnO) were synthesized as sulfur sorbents by the wet impregnation method. The crystal structure of the sorbents was determined by X-ray diffraction (XRD), while BET analysis was used to determine the surface area and pore size distribution of the sorbents. The results of the XRD and BET analyses revealed mixed metal oxide formation and a high surface area of SBA 15-supported sorbents, respectively. Mixed metal oxide formation was also confirmed by Fourier transform infrared radiation (FTIR) spectroscopy. The desulfurization performance of the sorbents was examined by a simulated gas mixture at 800 °C. A gas chromatography analyzer equipped with a flame photometric detector was used to follow the H2S concentration. SBA 15-supported CaO–MnO exhibited the best desulfurization performance at 800 °C with a breakthrough sulfur capacity (BSC) of 43.38 g S/100 g sorbent in the longest breakthrough time of 1077 min.

Numerical Analysis of Tar and Syngas Formation during the Steam Gasification of Biomass in a Fluidized Bed

A sequential modular hydrodynamic model integrated with detailed reaction kinetics (SMHM-RK) was developed and validated to predict tar and syngas components produced by the steam gasification of biomass in a fluidized bed gasifier. The simulations showed that the prediction accuracy is sensitive to both models for hydrodynamics and reaction kinetics. The simulations showed that the tar composition predicted by the SMHM-RK was more close to the measured values than those predicted by the well-mixed hydrodynamic model integrated with the same reaction kinetics (WMHM-RK). The predictions showed that the total tar decreased, but the polycyclic aromatic tar compounds increased with the increase in gasification temperature. There was an optimum steam-to-biomass ratio (SBR) for minimizing tar formation. The simulations found that the contents of total tar and heavy tar compounds decreased by increasing the SBR from 0.3 to 0.9, and then increased by further increasing the SBR. The injection of a small amount of oxygen in steam gasification cannot reduce tar formation. The injection of oxygen in steam gasification changed the reaction pathways of naphthalene to produce more naphthalene in the syngas. The de-volatilization rate affects pyrolytic volatile compositions and subsequent tar formation. Therefore, biomass devolatilization and homogeneous gas reactions should be solved simultaneously to accurately predict the syngas and tar composition.

Integrated capture and solar-driven utilization of CO2 from flue gas and air

Integrated capture and solar-driven utilization of CO2 from flue gas and air

Green/sustainable strategy for the enhanced thermal destruction of abandoned, lost, discarded fishing gears (ALDFGs)

One of the most prevalent wastes in the ocean is abandoned, lost, and discarded fishing gears (ALDFGs), which poses a potential mortality risk to all marine creatures. Considering the complex compositional nature and non-biodegradability, the thermal destruction of ALDFGs could offer a strategic measure to abate all hazardous potentials triggered by ALDFGs. More specifically, it is of paramount significance to completely break down ALDFGs into the smallest molecules such as syngas (H2 and CO). Also, the conversion of ALDFGs into the smallest molecular units offer an innovative means for neutralizing toxic chemicals (that are inevitably generated from thermochemical process) given that toxicity is proportional to the degree of aromaticity/substitution of heteroatoms (S, N, Cl, etc.). To enhance the overall thermal destruction efficiency, carbon dioxide (CO2) was used as a raw material. CO2 was employed as the renewable resource for carbon and oxygen to enhance syngas formation. In detail, this study experimentally proved the mechanistic contribution of CO2 to shifting carbon in wax-like/liquid hydrocarbons (HCs) into CO. The formation of CO from catalytic thermal destruction under CO2 condition was 64 times more than from thermal destruction without catalyst under CO2. Before the thermal destruction, the plastic types of ALDFGs (fishing rope (PP/PE), line (nylon 6), and net (PE)) were determined. Also, FT-IR analysis revealed that all plastics components in ALDFGs were partially oxidized.

Two-Stage Dry Reforming Process for Biomass Gasification: Product Characteristics and Energy Analysis

The utilization of biomass can not only alleviate the energy crisis but also reduce the pollution of fossil fuels to the environment. Biomass gasification is one of the main utilization methods, which can effectively convert biomass into high-value and wide-use gasification gas. However, this process inevitably produces the by-product tar, which affects the yield of syngas. In order to solve this problem, a two-stage process combining biomass pyrolysis and CO2 catalytic reforming is proposed in this paper, which is used to prepare high calorific value syngas rich in H2 and CO and reduce the by-product tar of biomass gasification while realizing the resource utilization of CO2. The effects of the reforming temperature and CO2/C ratio on the gas yield and calorific value of biomass were investigated by catalytic gasification reforming device, and the system energy consumption was analyzed. With the increase of reforming temperature, the yield of CO increased, and the yield of H2 and the calorific value of gas increased first and then decreased. Increasing the CO2/C ratio within a proper range is beneficial to the formation of syngas. When the reforming temperature is 900 °C and the CO2/C ratio is 1, syngas with a high gas calorific value is obtained, which of is 2.75 MJ/kg is obtained. At this time, the yield of H2 and CO reached the maximums, which were 0.46 Nm3/kg and 0.28 Nm3/kg, respectively. Under these conditions, the total energy consumption of the system is 0.68 MJ/kg, slightly more than 0, and does not require too much external heat.