Biomass Steam Gasification Research Articles

Design and performance analysis of a solar dual fluidized bed gasifier

The potential to conduct allothermal steam-gasification of biomass using a dual fluidized bed gasifier (DFBG) assisted by solar energy has already been conceptually proposed. In this paper the design and operation of a solar DFBG (SDFBG) device to deal with this concept is assessed by modeling, considering thermodynamic, kinetic and fluid-dynamic issues. The challenges identified in previous works, as well as the modifications required in the current state-of-the-art technologies of (no-solar) DFBG for implementing the new solution using heated particles as heat carriers, are worked out. Two SDFBGs, considering different arrangements for integrating the solids carrying the solar energy into the system, are designed. The operation of both under different solar-external heat loads, from autothermal operation (no external heat) to 3 MJkgbio,daf−1 of external heat, is assessed and compared. This work shows how the technology can be implemented and scaled up.

Fuel cell integrated carbon negative power generation from biomass

Combining biomass-fuelled power plant with carbon capture and storage allows CO2 to be removed from the atmosphere, considering biomass a carbon–neutral fuel. In the present study, a biomass-based CO2 negative system has been proposed, which combines a biomass steam gasification facility with a solid oxide fuel cell, a post-combustion carbon capture facility with a molten carbonate fuel cell (MCFC), and waste heat recovery using the organic Rankine cycle. A techno-economic analysis of two scenarios, namely a) with MCFC-based CO2 capture and b) without CO2 capture, was conducted. Integration of MCFC and carbon capture system was able to capture 99.2% of CO2. It was found that the energy efficiency of the system was decreased by 9.43%, with the incorporation of CO2 capture facilities. Furthermore, exergy efficiencies for the configuration with CO2 capture and without CO2 capture are calculated as 62% and 70.22%, respectively. The economic analysis reveals that the levelized cost of electricity (LCOE) for the configuration with CO2 capture and without CO2 capture is estimated to be 0.062 $/kWh and 0.052 $/kWh, respectively. Finally, life cycle CO2 emissions for both the scenarios have been performed, and the analysis reveals that the proposed CO2 negative system is able to capture 1100 tonnes of CO2 per year.

Syngas Production for Fischer-Tropsch Synthesis from Rubber Wood Pellets and Eucalyptus Wood Chips in a Pilot Horizontal Gasifier with CaO as a Tar Removal Catalyst.

This research aims to investigate steam biomass gasification in a pilot horizontal gasifier using rubber wood pellets (RWPs) and eucalyptus wood chips (EWCs) for producing syngas with an H2/CO ratio range of 1.8 to 2.3 for Fischer-Tropsch synthesis. The study was divided into two parts. One was carried out in a lab-scale reactor to determine the effect of temperature and CaO on the gas product composition and the efficiency of tar removal. Another part was determined by investigating the effect of the steam/biomass (S/B) ratio on the produced H2/CO ratios in the pilot horizontal gasifier, which used the optimum conditions of temperature and % loading of CaO for tar removal according to the optimal conditions from the lab-scale gasifier. The lab-scale gasifier results showed that H2 and CO2 increased with temperature due to primary and secondary water gas reactions and hydrocarbon reforming reactions. The water gas shift and hydrocarbon reforming reaction depressed the CO and CH4 contents with increasing temperature, respectively. The optimum gasifying temperature was 900 °C, which obtained H2/CO ratios of 1.8 for both RWPs and EWCs. The tar yield decreased with increasing temperature and was less than 0.2 wt % when using CaO as a tar-cracking catalyst. The operation of the pilot horizontal gasifier at the operating condition of 900 °C and a S/B ratio of 0.5 using 0.2 wt % loading of CaO for tar removal also produced a H2/CO ratio of 2.0. The supply of an external heat source stabilized the gasifying temperature, resulting in a stable syngas composition and production rate of 2.5 and 2.7 kg/h with H2/CO ratios of 1.8 and 1.9 for the RWPs and EWCs, respectively. In summary, the horizontal gasifier is another effective designed gasifier that showed high-performance operation.

Study on counter-flow steam gasification characteristics of biochar with Fe2O3/CaO in-situ catalysis in fixed bed

It is important to explore a relatively cheap and efficient biomass steam gasification process for the high-value utilization of biomass. Biochar was used as raw material for steam gasification, and the steam gasification of counter-flow biochar fixed bed was enhanced by the in-situ catalysis of Fe2O3 and CaO. By changing the steam flow rate and heating temperature, the operating characteristics of counter-flow gasification were explored and compared with updraft and downdraft gasification.The experimental results show that the addition of CaO in counter-flow gasification can improve the gasification intensity of biochar at lower temperature and steam flow rate. At 750 ℃, the biochar loaded with CaO at steam flow rate of 3.75 ml/min has a maximum heating temperature LHV of 11.49 MJ/Nm3. As the heating temperature increases, the hydrogen production yield gradually decreases. At temperature of 850 ℃ and steam flow rate of 3.75 ml/min, the gasification intensity of CaO loaded biochar was 66.44 % higher than that of unloaded biochar, and the gasification intensity was increased by 15.04 % by loading Fe2O3. However, the addition of Fe2O3 can improve the hydrogen production yield of biochar. At 850 ℃ gasification temperature, the hydrogen production yield is 23.25 % higher than that of biochar without catalysis.

Steam Gasification of Biomass for Hydrogen Production – A Review and Outlook

This article summarizes various biomass gasification methods and explains their advantages and disadvantages. First, theoretical aspects of gasification and the variety in reactor designs are overviewed. Despite the eminent effect of reactor design on gas product quality, gasification agents remain the dominant factor that determines the gas composition. Steam gasification is a thermochemical process that promotes organic carbonaceous substances into carbon monoxide and hydrogen while reducing the presence of dilutants. However, several obstacles during gasification and downstream processing have to be overcome to achieve adequate maturity. Gasification characteristics of steam were compared to the other gasification agents, including air, oxygen and CO2. The key performance parameters affecting steam gasification include raw material properties, additive and catalytic materials. While the key operating parameters include operating temperature, residence time, superficial velocity, equivalence ratio and steam-to-biomass ratio. Finally, the techno-economic evaluation and challenges facing the commercialization of steam gasification were discussed.

Improving catalyst performance of Ni-CaO-C to enhance H2 production from biomass steam gasification through induction heating technology

Catalyst performance plays a key role in biomass gasification for H2 production. In this study, induction heating technology was proposed to in-situ heat Ni-based catalyst via Joule heating effect to improve the catalyst performance during steam gasification of biomass for enhancing H2 production. Scanning electron microscope, Brunauer-Emmett-Teller, Thermogravimetric analysis and X-ray diffraction analysis confirmed that less coke deposition, larger specific surface area and more active sites of Ni particles with better crystallinity degree were observed for the used Ni-CaO-C catalysts in induction heating reactor compared to conventional heating reactor (Electric resistance heating). Thus, Ni-CaO-C catalyst in induction heating reactor showed significantly higher catalyst performance, and the H2 production was greatly enhanced from 591–692 mL/g-biomass to 1097–1325 mL/g-biomass (increase rate up to 101.1 %). Furthermore, adding metallic particles into catalyst bed in induction heating reactor can also promote the catalyst performance and then enhanced H2 production. By using induction heating catalytic technology coupled with metallic particles addition, all the H2 yields from steam gasification of four typical biomass (reed straw, wheat straw, corn cob and rice husk) were increased (increase rates reached 106.6–133.5 %) compared to conventional heating reactor. And the ranking of the positive effects of Ni and metallic particles via induction heating on enhancing H2 production was as follows: Ni + Metallic particles coupling effect > Ni effect > Metallic particles effect. Under the optimal conditions, the H2 yields from these four biomass were as high as 1803, 1805, 1722 and 1740 mL/g-biomass, respectively.

Hydrogen rich Syngas by Steam gasification of Waste Lignocellulosic Biomass

The depleting petroleum reserve, as well as increasing demand for crude oil, has attracted the research interest for alternative sources of energy. The surplus lignocellulosic biomass such as forest residues, crop residues, and weeds may be a potential source to derive biofuel by the thermochemical route. Gasification is an established technology for the utilization of biomass to obtain producer gas containing mainly H2 and CO as combustibles. The air-blown biomass gasifiers are widely installed where the resulting producer gas contains 55-60 per cent nitrogen and a lower percentage of H2 and CO with an H2/CO ratio of less than one. Gasification of lignocellulosic biomass using steam as an oxidant produces syn-gas with a lower amount of nitrogen, a higher percentage of hydrogen, and H2/CO > 2.1. Steam as an oxidant favors water gas shift reaction with the formation of hydrogen and enhances the H2/CO ratio. The ratio of steam to biomass was 1.20-1.25 so the water gas shift reaction and steam reforming of methane occur. The percentage of hydrogen in the syngas obtained by gascification of pine needles, camelina straw and Lantana biomass was 56.8, 68.7, and 72.8 per cent respectively. The present article describes the steam gasification of pine needle biomass, crop residue from Camelina sativa, and biomass from weed i.e. Lantana camara to produce syngas with a higher H2/CO ratio along with a high calorific value compared to the one with air-blown gasification.

Heavy tar evolution characteristics during advanced sludge pyrolysis and biomass gasification integrated process

Sludge pyrolysis and biomass gasification integrated process (SPBG) is an attractive route for the comprehensive utilization of the two materials but more tar is produced in this process compared to traditional biomass steam gasification. Nitrogen-containing compounds in the tar bring threatens to the environment and heavy components in the tar contributes to undesired coke formation. In current study, the evolution of heavy tar, especially the nitrogen-rich components, during SPBG is revealed for the first time. It was found that heavy components were mainly distributed in the mass range of 150–450 Da, where aromatics consisted of carbon, hydrogen and nitrogen atoms were the most abundant. Deamination (NH3) and the combination of quinoline accompanied with the generation of the heavy components. Organics from sludge could react with biomass to form heavier oxygen-containing molecules. Meanwhile, steam from sludge promoted heavy components to crack by tar reforming reactions and consumed radicals in bio-char to inhibit the catalytic cracking of tar. Under the combination of above reactions, more heavy molecules were generated at low sludge volatile/biomass ratio and the aromatic content in the heavy tar decreased at high sludge volatile/biomass ratio.

Steam Gasification of Torrefied/Carbonized Wheat Straw for H2-Enriched Syngas Production and Tar Reduction.

Torrefaction/carbonization integrated with steam gasification of agricultural biomass for gas production and tar reduction was not investigated. The aim of this study was to evaluate the influence of the torrefaction/carbonization severity on H2-enriched syngas production and tar reduction during steam gasification of wheat straw (WS). The torrefaction/carbonization experiments were initially performed at 220–500 °C to examine the effect of pretreated temperature on the fuel properties of torrefied/carbonized WS. Then, the gasification temperature (700–900 °C) was optimized at 900 °C in terms of gas formation behaviors. Afterward, steam gasification of raw and torrefied/carbonized WS feedstocks was conducted. WS carbonized at 500 °C (WS-500) possessed the highest H2 concentration (54.21 vol%) and syngas purity (85.59%), while the maximum H2/CO molar ratio (1.83), high carbon conversion efficiency (90.33 C%) and cold gas efficiency (109.24%) were observed for WS torrefied at 280 °C. Notably, the cumulative gas yield, H2 yield, and syngas yield respectively reached 102.68 mmol/g, 55.66 mmol/g, and 87.89 mmol/g from steam gasification of WS-500. In addition, the carbonized WS feedstocks, especially WS-500, revealed a lower tar content. Simply put, integrating torrefaction/carbonization with steam gasification provided a novel and effective route to manufacture H2-enriched syngas with extremely low tar content from agricultural biomass.

Experimental investigation on the methanation of hydrogen-rich syngas in a bubbling fluidized bed reactor utilizing an optimized catalyst

Catalytic methanation processes allow the production of natural gas substitutes on a sustainable and renewable basis. This study investigates the catalytic methanation of syngas from dual fluidized bed steam gasification of biomass in an innovative bubbling fluidized bed methanation reactor with an optimized catalyst. Syngas from conventional gasification and a novel combination with syngas from sorption enhanced reforming were investigated. The applied fluidized bed reactor allowed an almost isothermal operation with optimal reaction temperatures between 320 °C–360 °C. Simultaneously, no chemical deactivation or mechanical attrition during 200 h of operation indicates a high long-term stability of the catalyst. The methane concentration downstream the methanation reactor increased from 43 to 74 vol.-%db through the methanation of a hydrogen-rich syngas produced via sorption enhanced reforming. Simultaneously, the methane yield is doubled to 95% and the hydrogen, carbon monoxide and carbon dioxide conversions are improved. Furthermore, it could be shown that a CO2 content below 1 vol.-%db is feasible in the (raw) synthetic natural gas, allowing grid injection without CO2 separation. The results indicate that sorption enhanced reforming in combination with an optimized fluidized bed methanation can lead to technical and economic improvements in sustainable synthetic natural gas production.

A comprehensive exergoenvironment-emergoeconomic-emergoenvironment based analysis of hybrid steam biomass gasification and solid oxide fuel cell system for a multigeneration system

The present study focused on the exergoenvironmental analysis via Life Cycle Assessment and emergy based evaluation of a multigeneration system of hydrogen, carbon dioxide, and power through biomass gasification (Sawdust). In this regards, energy, exergy, exergoeconomic, exergoenvironmental, emergoeconomic, and emergoenvironmental modeled in MATLAB software for a considered multigeneration system, is to employ hydrogen in a solid oxide fuel cell to increase power yield and to generate hydrogen and CO2 as output products. The Life Cycle Assessment for exergoenvironmental analysis has been performed in SIMA Pro based on Ecoindicator 99. Sensitivity analysis has been performed for the main decision variables of the considered multigeneration system based on energy, exergy, exergoeconomic, exergoenvironmental, emergoeconomic, and emergoenvironmental assessment.

MP-PIC Simulation of Biomass Steam Gasification Using Ilmenite as an Oxygen Carrier

Biomass chemical looping gasification (BCLG) is a complex process for the conversion of biomass using an oxygen carrier, which is influenced by various operating parameters. For a better understanding of this process, biomass steam gasification using ilmenite as an oxygen carrier is numerically investigated in this work using the multiphase particle-in-cell (MP-PIC) method, which is a modified Euler–Lagrange approach. As a first step, a reduced reaction network for biomass gasification is investigated in a spouted bed. As a second step, the reaction network is coupled with oxygen carrier kinetics of ilmenite for the simulation of BCLG in a lab-scale fluidized bed. For both steps, the influence of the main operating parameters, such as reactor temperature, steam-to-biomass ratio, and oxidation degree of the oxygen carrier, are investigated and compared with experimental data from the literature. In general, the simulations show satisfying results and the predicted syngas compositions with varied operating parameters are in good agreement with the experimental data. Furthermore, the main trends for the syngas composition are predicted correctly and the oxidation degree of the oxygen carrier has a significant influence on the resulting syngas composition confirming the experimental results.

Integration of steam gasification and catalytic reforming of lignocellulosic biomass as a strategy to improve syngas quality and pollutants removal

Residual biomass gasification is a promising route for the production of H2-rich syngas. However, the simultaneous formation of pollutants such as light hydrocarbons (HCs), benzene, toluene and xylenes (BTEX), polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) during gasification must be controlled. As a result, this study evaluated the effect of temperature and catalytic reforming over a Rh-Pt/CeO2-SiO2 catalyst during steam gasification of sugarcane residual biomass on syngas composition and pollutant removal. The above was carried out in a horizontal moving reactor, an Amberlite XAD-2 polyaromatic resin was used to collect the contaminants and characterization of the catalyst was performed. In this study, a concentration of up to 37 mol% of H2, a yield of 23.1 g H2 kg−1biomass, and a H2/CO ratio ≥2 were achieved when gasification and reforming were integrated. In addition, the catalyst characterization showed that Rh-Pt/CeO2-SiO2 was not susceptible to sintering and favored the formation of hydroxyl groups that promoted CO oxidation, thereby increasing the H2/CO ratio, as confirmed by in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). At 800 °C, where a high H2 yield was obtained, 209 g Nm−3 of light HCs and BTEX, 10.9 g Nm−3 of PAHs, and 32.5 ng WHO-TEQ Nm−3 of PCDD/Fs were formed after gasification. Interestingly, after catalytic reforming, 62% of light HCs and BTEX, 60% of PAHs, and 94% of PCDD/Fs were removed, leading to cleaner syngas with properties that allow it to be used in a wide range of energy applications.

Application of Fe Based Composite Catalyst in Biomass Steam Gasification to Produce Hydrogen Rich Gas.

A series of composite catalysts with different Fe-based load amounts were prepared and applied to the experiment of biomass gasification assisted by steam. The structure of the catalyst was analyzed by XRD, SEM, TEM, N2 adsorption-desorption, and H2-TPR. The effect of the change of Fe load amounts on the catalytic activity was studied, and the optimal conditions of the gasification reaction were selected. The relationship between catalyst structure and catalytic capacity was clarified. The results showed that under the optimal reaction conditions, the catalyst showed better catalytic activity when Fe load amounts were 10%. The proportion of hydrogen in the gasification gas is as high as 42.2% and the hydrogen production is 27.65 g/kg. The tar content reaches the lowest value of 34.07g/Nm3.

Heat integration and waste minimization of biomass steam gasification in a bubbling fluidized bed reactor

Steam gasification of biomass generates a hydrogen-rich product gas that is diluted in unreacted steam and contaminated with tar. In this study, a novel heat integration alternative is conceptualized through syngas cooling to near-ambient temperature via an indirect water condenser downstream of a bubbling fluidized bed gasifier. The steam generated from heat recovery is used for biomass gasification, whereas the condensed bio-oil (unreacted tar and steam) is collected and recycled to the gasifier for further conversion. A one-dimensional kinetic model is developed and tested against experimental data from the literature on steam gasification of bio-oil and steam gasification of biomass in two separate bubbling fluidized bed gasifiers. The average absolute deviation of model predictions for CO2, CO, CH4 and H2 mole fractions are 60.85%, 14.25%, 30.17% and 10.75% for bio-oil steam gasification and 80.63%, 27.70%, 67.28% and 4.71% for biomass steam gasification, respectively. Based on the agreement observed between the model predictions and experimental data over substantial ranges of operating conditions, the same approach is adopted for modeling integrated biomass and recycled bio-oil gasification. Increasing bio-oil recycle ratio increases water conversion and chemical efficiency at the cost of decreasing carbon conversion and thermal efficiency of biomass gasification process. In addition to reactor temperature and steam-to-biomass ratio, tar recycle ratio can be utilized as an optimization variable to compromise between process chemical and thermal efficiencies, as well as wastewater production. Finally, an economic analysis shows that an incremental return on investment of >33% is achievable for the integrated process.

Kinetic Model of Catalytic Steam Gasification of 2-Methoxy-4-methylphenol Using 5% Ni–0.25% Ru/γAl2O3 in a CREC-Riser Simulator

Hydrogen is an energy vector with a great potential due its ample range of applications and clean combustion cycle. Hydrogen can be produced through biomass steam gasification, with novel catalysts being of significant value to implement this process. With this goal in mind, in the present study, 5 wt % Ni/γAl2O3 promoted with 0.25 wt % Ru was synthesized and characterized. It is assumed that ruthenium facilitates hydrogen transfer to nickel oxide sites, promoting a hydrogen spillover effect, with the H2 adsorbed on Ru being transported to Ni sites. To describe chemical changes, the present study considers a kinetic model involving Langmuir–Hinshelwood-based rate equations, as a sum of independent reactions, with this being applied to the steam gasification of 2-methoxy-4-methylphenol (2M4MP). This tar biomass surrogate was studied in a fluidized CREC (Chemical Reactor Engineering Centre) Riser Simulator reactor, at different reaction times (5, 20 and 30 s.) and temperatures (550 °C, 600 °C and 650 °C). The proposed kinetics model was fitted to the experimentally observed H2, CO2, CO, CH4 and H2O concentrations, with the estimated pre-exponential factors and activation energies being in accordance with the reported literature data. It is anticipated that the postulated model could be of significant value for the modeling of other biomass conversion processes for hydrogen production using other supported catalysts.

Sorption-enhanced steam gasification of woody biomass assisted by Ca/Na/FS (fine slag) composite sorbents

In this research, composite sorbents with high activity in promoting H2 production during sorption-enhanced steam gasification of pine sawdust (PS) were developed by doping coal gasification fine slag (FS) and NaOH into calcined conch shell (CS). The tests performed in a laboratory-scale fixed bed reactor demonstrated that the composite sorbents greatly improved H2 concentration and yield over that achieved with CHCS (CS after hydration and calcination), reaching 73.5% and 600.7 mL/g-PS, respectively. This promotion effect on H2 production was not influenced by the unburned carbon in FS. To obtain high H2 concentration and yield with as little NaOH and as much FS as possible, the optimum sorbent was found to be 3CS-2FS-0.32Na (in mass ratio of CS:FS:NaOH = 3:2:0.32). Under this condition, the H2 concentration and yield reached 74.3% and 572.3 mL/g-PS, respectively. In five cycles of experiment, although the H2 yield of 3CS-2FS-0.32Na decreased from 572.3 mL/g-PS to 416.6 mL/g-PS, it was always higher than with CHCS alone by at least 28%. The results in this study indicate that FS has potential to be an effective inert support material that endows CaO with high activity in H2 production during sorption-enhanced steam gasification. This might help to provide a new approach to minimizing the negative environmental impact of FS.

Calculations of complex chemical reaction equilibria using stoichiometric and non‐stoichiometric approaches in combination with arc‐length continuation

AbstractChemical equilibrium calculations—as they are required to evaluate the evolution limits of any reactive system—are fundamentally performed using either a reaction based stoichiometric (S) approach or a non‐stoichiometric (NS) method. One objective of the present paper is to check and discuss whether both methods lead to comparable solutions in the case of complex chemical equilibria encountered in high temperature and pressure combustion of hydrazine and propane and in steam gasification of glucose and cellulose. Within both calculation models various numerical methods can be used. We apply several techniques for each approach and discuss their easiness of implementation and usage, in particular when chemical equilibria are computed for reacting systems under a multitude of temperature and pressure conditions and feed compositions. In addition, we present a novel approach to perform sensitivity analyses based on a combination of S or NS methods and arc‐length continuation technique. For this purpose, three industrially relevant case studies are exposed: (1) synthesis of ammonia using the Haber process, (2) steam gasification of a typical biomass surrogate, glucose, and (3) steam gasification of cellulose. For all the above reacting systems, our results are benchmarked against their counterparts obtained either from the ubiquitous process simulator: ASPEN‐Plus® or from data available in the open literature.

Enhanced H2 production from steam gasification of biomass by red mud-doped Ca-Al-Ce bi-functional material

The sorption-enhanced steam gasification of biomass (SESGB) using CaO-based materials is considered as a promising method for H2 production. Ca-Al-Ce material has been reported as a good bi-functional material in SESGB process. Red mud is a solid waste in aluminium industry with large yield, which is rich in Fe2O3. In this work, a red mud-doped Ca-Al-Ce bi-functional material was prepared by wet-mechanical mixing method for H2 production from SESGB. The CO2 capture, H2 production, and tar reduction performances during SESGB process using the red mud-doped Ca-Al-Ce bi-functional material were studied. The results show that the optimum addition amount of red mud in the bi-functional material is 5 wt%. After 20 SESGB cycles, the H2 concentration using the red mud-doped Ca-Al-Ce material achieves 65.1 vol%, which is 82.4% higher than that using Ca-Al-Ce material. Besides, with the addition of red mud in the bi-functional material, the tar, residue char yields and CO2 concentration decrease by 25.2%, 8.6% and 52.2%, respectively. Fe2O3 in the red mud reacts with CaO to form Ca2Fe2O5 in the 1st cycle, and Ca2Fe2O5 is stable during 20 cycles, which is beneficial for the generation of oxygen vacancy. The oxidation states of Fe species in the material increase with the number of SESGB cycles, thus the catalytic effects on water gas shift reaction and tar reduction are promoted. The red mud addition is the key factor that results in high H2 production, CO2 capture and tar reduction performances, so the red mud-doped Ca-Al-Ce material appears promising for SESGB.

Simulation of steam gasification of halophyte biomass for syngas production using Aspen Plus®

Simulation of steam gasification of halophyte biomass for syngas production using Aspen Plus®