Process For Syngas Production Research Articles

Improvement of Process Conditions for H2 Production by Chemical Looping Reforming

A syngas production process was studied cyclically, exploiting the redox properties of Ce-based oxygen carriers. The two steps of the looping cycle were investigated through thermogravimetric analysis and fixed bed experiments. While TGA experiments were focused on the identification of the optimal temperatures ranges for methane partial oxidation (900–1000 °C) and carrier regeneration (400–900 °C), fixed bed testing was performed isothermally (at 900 or 950 °C), with a 10% CH4 feed stream in N2 to investigate material stability and cyclic performance reproducibility. The effect of the process times on carbon deposition, specific syngas yields, and selectivity was inspected, together with the investigation of best conditions to fully regenerate the carrier, adjust the syngas final ratio, and to ensure stable performances. The obtained results ensured the possibility to work in fully isothermal operations, with CH4 conversion of up to 38% and specific yields of syngas per mass of O2 carrier between 4.0–6.8 mmol∙g−1, preserved even across cycles, thus paving the path to the development of alternative and effective processes for syngas production. Under the operating conditions of the lab-scale experiment, an effective reforming time was 20 min, corresponding to 1.16 times of the characteristic time of reaction kinetics at 950 °C.

Thermodynamic analysis of using CO2 as a co-gasification agent in supercritical water gasification of glycerol

Using CO2 as a co-gasification agent in supercritical water gasification (SCWG) of glycerol is one of the promising approaches for syngas production. In this study, a non-stoichiometric two-phase model (i.e., supercritical and solid phase) is used for thermodynamic analysis of supercritical H2O-CO2 co-gasification (SCWCG) of glycerol. The Gibbs free energy of the entire system is minimized to calculate the equilibrium compositions of gaseous and solid products. The chemical potentials of gaseous products are accurately predicted by using the PR-BM equation of state. The validity of the established model is initially confirmed through its fitting with experimental data. Subsequently, the model is used to investigate the effects of various single and combined operating conditions on product compositions. The findings indicate that temperature, CO2 addition and glycerol concentration have significant influence on the process performance, whereas the pressure has a negligible effect. In addition, the theoretical maximum H2 molar fraction of 68.15% are obtained. Furthermore, the reaction heat duty and high heating value of gaseous products are analyzed. When the glycerol concentration is low, the SCWCG process turns out to be endothermic and can be energetically self-sufficient by adding a small amount of O2 at the expense of reducing the heating value of gaseous products. The study provides valuable insights on designing an optimal SCWCG process for syngas production from glycerol.

Development of a green process based on a novel tri-reforming reactor to produce syngas for methanol synthesis: Process Design, Modeling and Multi objective optimization

In this study, a clean and energy-efficient reforming process is introduced that can act as a promising alternative to the conventional reforming process for syngas production used in methanol synthesis process. In this proposed configuration, a pre-reformer is combined with a novel tri-reformer consisting of a combustion chamber and a catalytic bed. The combustion chamber was simulated using the CHEMKIN package incorporating GRI3.0 as a comprehensive mechanism and the catalytic bed was modeled by a heterogeneous plug flow model. A multi-objective optimization model was used to explore operational conditions of the proposed process to optimize CH4 conversion, H2 yield, and CO2 net production. Hence, the other aspect of novelty in this study deals with the use of a new methodology for multi-objective optimization of this process. This methodology is the first to integrate the CHEMKIN package and MATLAB software that leads to a higher degree of accuracy and comprehensiveness. The mathematical model of the conventional process was also developed and the favorable comparison between the performances of both processes was studied. The results indicate that eliminating a steam reformer in the novel configuration, not only reduces toxic emissions and the need for a large quantity of energy, but it also significantly decreases the required value of H2O/CH4 ratio. Therefore, the steam content of the process gas is reduced and energy efficiency is improved. Analyzing the characteristics of the synthesis gas produced by the studied cases results, that the proposed case produces a synthesis gas with higher quality (SN = 2 and a higher CO/CO2 ratio) while substantially reducing energy consumption as well as toxic emissions production.

Advanced application of a geometry-enhanced 3D-printed catalytic reformer for syngas production

Catalyst research on reforming processes for syngas production has mainly focused on the active metals and support materials, while the effect of the catalyst’s geometry on the reforming reactions has been poorly studied. The application of 3D-printed materials with enhanced geometries has recently started to be studied in heterogeneous catalysis and is of interest to be implemented for reforming biomass and plastic waste to produce H2-rich syngas. In this study, a geometry-enhanced 3D-printed Ni/Al2O3/FeCrAl-based monolithic catalyst with a periodic open cellular structure (POCS) was designed and fabricated. The catalyst was used for batch steam reforming biomass pyrolysis volatiles for syngas production at different parameters (temperature and steam-to-carbon ratio). The results showed complete reforming of pyrolysis volatiles in all experimental cases, a high H2 yield of ≈ 7.6 wt% of biomass was obtained at the optimized steam-to-carbon ratio of 8 and a reforming temperature of 800 °C, which is a higher yield compared to other batch reforming tests reported in the literature. Moreover, CFD simulation results in COMSOL Multiphysics demonstrated that the POCS configuration improves the reforming of pyrolysis volatiles for tar/bio-oil reforming and H2 production thanks to enhanced mass and heat transfer properties compared to the regular monolithic single-channel configuration.

Techno-Economic Assessment of High-Safety and Cost-Effective Syngas Produced by O2-Enriched Air Gasification with 40–70% O2 Purity

To strike a better balance between gas quality and production cost of biomass-based syngas, a process for high-safety and cost-effective syngas production is designed and studied, which takes advantage of biomass O2-enriched air gasification with 40–70% O2 purity and methanation synthesis. Based on the simulation data, the process is evaluated from techno-economic aspects, including syngas composition, higher heat value (HHV), upper and lower explosive limits (UEL and LEL), toxicity, unit production cost (UPC) and levelized cost of energy (LCOE). Five kinds of biomass are studied as feedstock. The effects of O2 purity, methanation pressure, feedstock cost, and plant scale are determined, respectively. The results show that O2 purity is an important parameter for technical performance, while methanation pressure is a minor parameter except for exergy efficiency. With respect to cost indicators, feedstock cost, and plant scale are crucial variables; by contrast, O2 purity plays a relatively minor role. This process can generate non-toxic syngas containing 33.2–34.9 vol.% CH4. The UEL and LEL are about 34% and 12%, and the average explosive range is about 22%. The HHVs of syngas generated from five kinds of feedstock sit between 13.67–14.33 MJ/m3, and the exergy efficiency achieves 68.68%. The UPC varies between 0.05 $/Nm3 and 0.27 $/Nm3, and the LCOE varies between 3.78 $/GJ and 18.28 $/GJ. When the plant scale is rational, the process shows strong competitiveness in either UPC or LCOE. The techno-economic results demonstrate that the studied process offers an alternative and sustainable pathway to supply gaseous fuel for low-income areas.

Solar metallurgical process for high-purity Zn and syngas production using carbon or biomass feedstock in a flexible thermochemical reactor

Co-production of high-purity Zn and syngas via carbothermal reduction of ZnO was performed in a directly-irradiated concentrated solar reactor, thereby converting and storing intermittent sunlight into high-value chemical fuels and commodities. On-sun experiments were carried out by varying operating parameters including solid carbonaceous feedstocks (either solid carbon or beech wood biomass) in batch and continuous modes at 950–1350 °C, demonstrating solar reactor flexibility and robustness. Decreasing pressure (150–400 hPa) promoted both ZnO reduction rate and net ZnO conversion above 78%, thus enhancing Zn production yield. Nevertheless, CO selectivity decreased because of rising CO2 due to the residence time decrease. A remarkable increase in gas production rates/yields, CO selectivity, and reaction extent was highlighted when increasing temperature during continuous pellets reactant injection. Furthermore, utilizing wood biomass as a sustainable green reducer was proved to be an attractive choice to produce both metallic Zn and high-quality syngas in a single process consisting of biomass gasification with solid ZnO. Zn content exceeding 90 wt% was demonstrated for both batch and continuous tests, unveiling high reactor performance for the metallurgical process. The energy content of the feedstock was upgraded by the solar power input (maximum energy upgrade factor up to 1.2), and the maximum solar-to-fuel energy conversion efficiency up to ∼ 6% was achieved with continuous reactant injection. The high-purity Zn can be further used to produce fuel via CO2-splitting in a complete and fast reaction.

Experimental and simulation study of peanut shell-derived activated carbon and syngas production via integrated pyrolysis-gasification technique

Carbonaceous materials are among the most appropriate and widely used materials in the field of energy production, conversion, and storage. According to recent studies, biochar-based catalytic supports and adsorbents have shown great potential in the fields of energy production and the adsorption and storage of various gases due to their adjustable surface chemistry and porosity. In the present study, the pyrolysis of peanut shell to produce activated carbon as a precursor for catalyst support was investigated. Acid washing pretreatment was performed on raw biomass before pyrolysis to remove metals and impurities and reduce the ash content of the biomass. Before pyrolysis, thermogravimetric analysis was performed to determine the temperature range of biomass thermal decomposition. Pyrolysis was carried out at temperatures of 300, 400, and 500 °C to study the effect of pyrolysis temperature on biochar yield. KOH-activation on biochar was followed by subsequent pyrolysis at 650 °C to produce activated carbon. To study the effect of pyrolysis temperature and KOH activation on the structural and physiochemical characteristics of biochar, nitrogen adsorption/desorption and FTIR analyses were conducted. The pore size of the activated carbon surface changed from mesoporous to microporous with increasing the pyrolysis temperature and subsequent KOH activation, and the biochar specific surface area increased from 3.5 to 363.1 m2 g-1. In order to evaluate and optimize the operating conditions of the biochar and syngas production processes on larger scales, the integrated pyrolysis and gasification processes were simulated in Aspen Plus software. The effects of temperature, pressure, and air to biomass ratio on biochar production rate and H2/CO ratio were evaluated. A temperature of 650 °C, a pressure of 1 bar and an air to biomass ratio of 0.1 were selected as optimum operating conditions to simultaneously achieve maximum biochar production and maintain the quality of synthetic gas. The findings of the experimental and simulation sections of this study could provide a useful guide for the industrial-scale production of biochar and activated carbon as a catalytic support in various chemical production processes, as well as a water polutant adsorbent and gas adsorbent for various gas purification and storage processes.

Simulation analysis of bio-oil reforming for co-production syngas and high purity H2 or CO2 with chemical looping processes

Chemical looping allows for the production of different products, such as syngas, high-purity hydrogen and high concentration CO2, through a single process without the need for separation. In this study, a detailed analysis is investigated by utilizing Aspen Plus software to explore the feasibility of bio-oils efficient utilization in four chemical looping processes. The Sorption Enhanced Steam Reforming (SESR) process for syngas production with CO2 capture can be modified into an autothermal process by combusting a fraction of the syngas, leading to a syngas yield of 11.04 (mol/mol fuel) and a CO2 capture capacity of 4.18 (mol/mol fuel). The Calcium and Chemical Looping Reforming (CaL-CLR) process is a unique approach to attaining the greatest syngas yield of 11.31 (mol/mol fuel) and capturing the highest CO2 of 5.40 (mol/mol fuel) simply by adjusting the flow rate of NiO oxygen carrier to realize autothermic reforming without compromising the syngas output. Nevertheless, the integration of NiO and air reactor (AR) will lead to increased financial and operational outlays. For co-production of syngas and high-purity hydrogen, the Three-Reactors Chemical Looping Hydrogen (TR-CLH) process can produce high-purity hydrogen with 5.70 (mol/mol fuel) under autothermal conditions, but the syngas yield and purity are low. The Chemical Looping Reforming and Water Splitting (CLRWS) process has the potential to create a substantial syngas yield, up to 9.63 (mol/mol fuel), as well as a considerable flow rate of high-purity hydrogen, 8.42 (mol/mol fuel). It is clear that this process is more successful than other processes available; however, the excessively high temperature of the fuel reactor (FR) impedes its further utilization.

CO2 utilization for the production of liquid hydrocarbons by coupled steam and dry reforming of bioethanol

ABSTRACT Ethanol is an interesting fuel that can be produced by both renewable and nonrenewable resources and can be used as fuel or additive to fuels. But bioethanol is not equivalent one by one by fossil fuels in vehicles. In this study, the production of liquid hydrocarbons as synthetic fuels using bioethanol reforming has been simulated by Aspen HYSYS. For this purpose, two processes for syngas production have been proposed: 1: bioethanol steam reforming (ESR) and 2: bioethanol steam reforming coupled with dry reforming (ESR+EDR). Effective parameters including temperature, steam-to-carbon ratio, residence time, and feed split ratio have been evaluated. It is shown that the value of H2/CO using the syngas produced from ESR is in the range of 5. This ratio was modified using ESR+EDR without and with CO2 injection by 2.5 and 2, respectively. These values are suitable for the production of liquid hydrocarbons in the gasoline range. The C5 + selectivity using synthesis gas produced in the Fischer-Tropsch reactor in the ESR and the ESR+EDR without and with CO2 injection has been obtained by is 17.21%, 40.43%, and 42.96%, while CO2 selectivity has been emitted by 0.11, 0.53, and 0.71.

Noncatalytic Syngas Production Processes and Possibilities of Reducing the СО2 Emission into the Environment

Noncatalytic Syngas Production Processes and Possibilities of Reducing the СО2 Emission into the Environment

Process Analysis of Chemical Looping Gasification of Biomass for Fischer–Tropsch Crude Production with Net-Negative CO2 Emissions: Part 1

Large-scale biofuel production plants require an efficient gasification process that generates syngas of high quality (with minimal gas contaminants and inert gases) to minimize the extent of the syngas cleaning processes required for liquid biofuel production. This work presents process modeling of the chemical looping gasification (CLG) process for syngas production. The CLG process is integrated with a Fischer–Tropsch synthesis (FTS) process to produce Fischer–Tropsch (FT) crude with net-negative CO2 emissions, enabling process and system-level analyses of this novel biomass-to-liquid process. CLG resembles indirect gasification in an interconnected circulating fluidized bed reactor, where instead of inert bed material, a solid-oxygen carrier, such as mineral ores rich in iron or manganese oxides, is used. The oxygen carrier particles undergo oxidation and reduction in the air reactor and fuel reactor, respectively, thereby providing heat and oxygen for gasification. This work uses data from CLG experiments performed with steel converter slag as the oxygen carrier and investigates its potential when integrated with different downstream gas cleaning trains and the subsequent fuel synthesis process with the primary objective of quantifying and evaluating the performance of the integrated CLG–FT process plant. Syngas with a high energy content of 12 MJ/Nm3 (lower heating value basis) is predicted with a cold gas efficiency of 73%. CO2/CO ratios, higher than indirect biomass gasification, are also predicted in the raw syngas produced; thus, there exists an opportunity to capture biogenic CO2 with a relatively lower energy penalty in the subsequent gas cleaning stages. This work quantifies other key performance indicators, such as heat recovery potential, negative CO2 emission capacity, and FT crude production efficiency of the CLG–FT plant. A 100 MWth CLG plant produces roughly 677–696 barrels per day of FT crude, with net-negative emissions of roughly 180 kilotonnes of CO2 annually.

Quo Vadis Dry Reforming of Methane?—A Review on Its Chemical, Environmental, and Industrial Prospects

In recent years, the catalytic dry reforming of methane (DRM) has increasingly come into academic focus. The interesting aspect of this reaction is seemingly the conversion of CO2 and methane, two greenhouse gases, into a valuable synthesis gas (syngas) mixture with an otherwise unachievable but industrially relevant H2/CO ratio of one. In a possible scenario, the chemical conversion of CO2 and CH4 to syngas could be used in consecutive reactions to produce synthetic fuels, with combustion to harness the stored energy. Although the educts of DRM suggest a superior impact of this reaction to mitigate global warming, its potential as a chemical energy converter and greenhouse gas absorber has still to be elucidated. In this review article, we will provide insights into the industrial maturity of this reaction and critically discuss its applicability as a cornerstone in the energy transition. We derive these insights from assessing the current state of research and knowledge on DRM. We conclude that the entire industrial process of syngas production from two greenhouse gases, including heating with current technologies, releases at least 1.23 moles of CO2 per mol of CO2 converted in the catalytic reaction. Furthermore, we show that synthetic fuels derived from this reaction exhibit a negative carbon dioxide capturing efficiency which is similar to burning methane directly in the air. We also outline potential applications and introduce prospective technologies toward a net-zero CO2 strategy based on DRM.

Reforming processes for syngas production: A mini-review on the current status, challenges, and prospects for biomass conversion to fuels

Dedicated bioenergy combined with carbon capture and storage are important elements for the mitigation scenarios to limit the global temperature rise within 1.5 °C. Thus, the productions of carbon-negative fuels and chemicals from biomass is a key for accelerating global decarbonisation. The conversion of biomass into syngas has a crucial role in the biomass-based decarbonisation routes. Syngas is an intermediate product for a variety of chemical syntheses to produce hydrogen, methanol, dimethyl ether, jet fuels, alkenes, etc. The use of biomass-derived syngas has also been seen as promising for the productions of carbon-negative metal products. This paper reviews several possible technologies for the production of syngas from biomass, especially related to the technological options and challenges of reforming processes. The scope of the review includes partial oxidation (POX), autothermal reforming (ATR), catalytic partial oxidation (CPO), catalytic steam reforming (CSR) and membrane reforming (MR). Special attention is given to the progress of CSR for biomass-derived vapours as it has gained significant interest in recent years. Heat demand and efficiency together with properties of the reformer catalyst were reviewed more deeply, in order to understand and propose solutions to the problems that arise by the reforming of biomass-derived vapours and that need to be addressed in order to implement the technology on a big scale.

Modeling of methane Tri-reforming slurry bubble column reactor via differential evolution optimization method to produce syngas

Abstract Tri-reforming process of methane has been considered as an important chemical process for syngas production. The aim of this study is modeling and optimization of methane Tri-reforming slurry bubble column reactor (SBCR). A one-dimensional heterogeneous model with plug flow pattern for gas phase and an axial dispersion pattern for liquid-solid suspension has been developed for modeling of SBCR. differential evolution (DE) approach has been used for the optimization of Tri-reforming slurry reactor operating conditions. The effect of operating parameters such as inlet temperature, the ratios of O2/CH4, H2O/CH4, and CO2/CH4 on the temperature of gas, methane conversion, hydrogen production, and H2/Co ratio in the output of reactor are investigated. Methane conversion, hydrogen yield, and H2/Co ratio in optimization conditions were obtained 92%, 1.81, and 1.76, respectively. The results suggest that employment this type of reactor could be feasible and beneficial.

Syngas Generation Process Simulation: A Comparative Study

Methane reforming processes are of great importance for both the reduction of this greenhouse gas concentration in the atmosphere and for hydrogen production for energetic or chemical synthesis purposes. The use of Biogas in substitution for methane in reforming processes still provides a solution for the recovery of organic waste capable of producing Biogas. However, an in-depth analysis of the advantages of this substitution from the point of view of process yield is still lacking. Thus, the main contribution of the present research is the focus given to the comparison between methane and biogas as a reactant for the dry and steam reforming processes. In this work, a computational comparison of syngas production processes was performed, considering the system within the open-loop control. The software Aspen Hysys was used based on the minimization of Gibbs free energy in equilibrium. The parameters studied were: molar ratio of reagents (1-5), temperature (600-1000 °C), and pressure (1-5 bar). Dry methane reforming and steam methane reforming units were simulated, as well as both units using Biogas as a methane source. The plant was built in the simulator, and the results obtained indicated that high values in the molar ratio of CO2/CH4, CO2/Biogas, H2O/CH4, and H2O/Biogas, high temperatures, and low pressures favor the maximum conversion of methane. The use of Biogas in replacement of pure methane in the reform process proved to be advantageous for favoring the synthesis gas production reaction, besides adding value to a residue.

Trimetallic Catalyst Configuration for Syngas Production

AbstractDry reforming of methane (DRM) is a promising catalytic process for syngas production, utilizing and transforming CO2 to higher density compounds in view of circular economy. The performance of a bimetallic NiFe/MgAl2O4 strongly depends on the initial catalyst state – calcined, reduced or CO2‐reoxidized – that corresponds to different structures and is for each state significantly improved by the addition of a low Rh concentration (∼1 wt%). In the bimetallic catalyst, reduction is required to form the most active phase, a Ni3Fe alloy, showing a CH4 consumption rate of 0.9 mol s−1 kgcat−1. For the trimetallic NiFeRh, the effect of the initial state is less pronounced, yielding a CH4 consumption rate of 2.4 mol s−1 kgcat−1 after CO2‐reoxidation. Advanced characterization and modelling were used to gain insights in the trimetallic system and to systematically assess the role of each element. In NiFeRh, reduction leads to the formation of a trimetallic alloy. A subsequent CO2‐reoxidation induces partial Fe segregation from the trimetallic alloy, leading to separate Fe3O4. The latter structure represents the most active state due to the double role that the trimetallic catalyst takes up after H2‐reduction and CO2‐reoxidation: improved activity due to highly dispersed NiRh and NiFe alloy particles and carbon removal due to Fe3O4 particles.

Flexible operation of modular electrochemical CO2 reduction processes

Electrochemical CO2 reduction (eCO2R) is an emerging technology that is capable of producing various organic chemicals from CO2, but its high electricity cost is a big economic obstacle. One solution to reduce the cumulative electricity cost is demand side management, i.e., to adjust the power load based on time-variant electricity prices. However, varying the power load of CO2-electrolyzers often leads to changes in Faraday efficiency towards target components and thereby influences the product composition. Such deviations from the target product composition may be undesired for downstream processes. We tackle this challenge by proposing a flexible operating scheme for a modular eCO2R process. We formulate the economically optimal operation of an eCO2R process with multiple electrolyzer stacks as a parallel-machine scheduling problem. Adjusting the power load of each sub-process properly, we can save electricity costs while the desired product composition is met at any time. We apply an algorithm based on wavelet transform to solve the resulting large-scale nonlinear scheduling problem in tractable time. We solve each optimization problem with a deterministic global optimization software MAiNGO. We examine flexible operation of a modular eCO2R process for syngas production. The case studies show that the modular structure enables savings in the cumulative electricity cost of the eCO2R process via flexible operation while deviations in the syngas composition could be reduced. Also, the maximum ramping speed of the entire process is found to be a key parameter that strongly influences the cost saving.

Biomass chemical looping gasification for syngas production using modified hematite as oxygen carriers

Syngas is a clean energy carrier and a major industrial feedstock. In this paper, syngas was produced via biomass chemical looping gasification (CLG) process. Hematite, the most common Fe-based oxygen carrier (OC), was modified with different metal oxides (CeO2, CaO and MgO) by the impregnation method. The hematite modified by CeO2, CaO and MgO was namely as CeO2-hematite (CeO2-H), CaO-hematite (CaO-H) and MgO-hematite (MgO-H), respectively. The introduction of CeO2, CaO and MgO enhanced the reactivity of lattice oxygen of hematite. The optimum condition for syngas production had been explored as the mass ratio of oxygen carrier to biomass (O/B) of 0.2, the mass ratio of steam to biomass (S/B) of 0.75 and temperature of 800°C in the biomass CLG process. The CeO2-H exhibited the most wonderful performance compared to that for CaO-H and MgO-H. The crystal composition of OC influenced greatly in the CLG process. CeFeO3 had a good oxygen mobility property and lattice oxygen releasing capacity due to the most oxygen vacancy distributed on the OC surface and the most active lattice oxygen, which is conducive to the biomass chemical looping gasification process for syngas production, leading to the highest gasification efficiency of 95.86% and gas yield of 1.20 m3/kg of the three. Cyclic test proved that CeO2-H had well sintering resistance and cyclic performance.

Optimization of SMR process for syngas production through a solar-assisted thermo-chemical reactor with a multi-layered porous core

A two-dimensional steady-state axisymmetric model is developed to analyze the performance of a thermo-chemical porous reactor used for syngas and subsequently hydrogen generation through the steam methane reforming (SMR) process. The finite volume method coupled with kinetics thermo-chemical reaction and local thermal non-equilibrium (LTNE) model with modified P1 approximation is employed to obtain the temperature distribution for both the fluid and porous zones. First, the effects of inlet mass flow rate, inlet steam to methane ratio, porosity, number of pores per inch (PPI), permeability, and reactor length on reactor performance are scrutinized. Next, to optimize the performance of the reactor, an artificial neural network (ANN) is developed to obtain the maximum hydrogen generation rate concerning the effective parameters. Finally, a two-layer porous foam is utilized as the catalyst zone to further improve the performance. Results show that increasing inlet flow rate leads to temperature decline and causes an incomplete reaction. Also, increasing porosity enhances heat absorption at the inlet and decreases radiative heat transfer through the porous foam. At a specified condition (ṁ= 0.25 kg.h−1, XCH4/XH2O = 1/3, and PPI = 10), increasing the porosity from 0.6 to 0.8 has increased hydrogen production by 27 %, while by a further increase of porosity to 0.9, hydrogen production decreased by 3 %. Results indicate up to 164 % increment in the performance of the optimal case compared to the base case. Furthermore, employing the two-layer porous foam with different PPIs could further increase hydrogen production, up to 20 %, and reduced the pressure drop.

Simulation and exergoeconomic analysis of the syngas and biodiesel production process from spent coffee grounds

The integrated production of biofuels from agro-industrial wastes is increasing around the world. The thermodynamic performance and economic analysis of these processes have become topics of interest given the need to reduce the cost of biofuels and their impact on the environment. This study develops a simulation of the production process of syngas and biodiesel from spent coffee grounds, and an exergoeconomic analysis that mainly determines the exergy destruction rate, the investment and operational cost rate, and the exergy destruction cost rate at component level and for the overall system. The total investment cost for the integrated process resulted in 13.2 million dollars. The specific cost of syngas and biodiesel from spent coffee grounds were estimated in $0.36/kg and $0.71/kg, respectively. The results show that the drying process including the air heating for the pretreatment of the biomass had an exergy destruction rate of 11,463 kW and was responsible of the 92% of the overall exergy destruction cost rate. An increment of the dead state temperature reduced the specific cost of syngas and biodiesel in 17% and 8%, respectively. Future studies should focus on the exergoeconomic optimization of the drying process of biomass in order to minimize the operational costs.