Conventional Steam Methane Reforming Research Articles

Optimization of a novel hydrogen production process integrating biomass and sorption-enhanced reforming for reduced CO2 emissions

Recently, there has been a growing demand for clean and sustainable energy sources to bridge the energy gap. Hydrogen has emerged as an attractive and environmentally friendly energy carrier due to its potential for high energy efficiency and minimal pollution generation, making it a promising alternative to fossil fuels. This study proposes and investigates a novel coupled process that utilizes chemical looping technologies for hydrogen production, simultaneously utilizing natural gas and biomass as feedstocks. The primary objective of this research is to develop a process model that maximizes hydrogen production while minimizing carbon dioxide emissions. Aspen Plus version 10 was employed to simulate and analyze the proposed process configuration to achieve this. One of the proposed process's key advantages is its competitiveness compared to conventional steam methane reforming (SMR) processes, which are widely used in industry. The novel process offers significant benefits, such as enhanced hydrogen purity and reduced CO2 content in the product gas. The simulation results obtained from Aspen Plus reveal the successful production of highly pure hydrogen with a molar ratio of H2/CO equal to 268 and syngas with a molar ratio of H2/CO approximately equal to 1. Additionally, the process demonstrates the capability to produce highly high-purity hydrogen with a molar ratio of H2/CO equal to 155,000 in three-section reactors.

Life-cycle analysis of hydrogen production from water electrolyzers

The United States' focus on decarbonization has spawned interest among policymakers in deploying water electrolysis technology for clean hydrogen production. However, water electrolyzers also raise concerns regarding their substantial use of carbon-intensive materials. Here, we conduct a comprehensive life-cycle analysis (LCA) of three prominent water electrolyzer technologies to investigate the environmental implications of their manufacturing and life cycles under different energy sources. All electrolyzer technologies employing low-carbon energy (nuclear, solar, or wind) exhibit life-cycle greenhouse gas (GHG) emissions of 0.3–2.4 kg-CO2-eq/kg-H2. This is significantly lower than the corresponding GHG emissions for hydrogen production via both conventional steam methane reforming and alternative autothermal reforming with carbon capture and storage (by > 50%). The well-to-gate GHG emissions of low-carbon electrolyzers (0–0.36 kg-CO2-eq/kg-H2) qualify for Tier I of the production tax credit in the U.S.’ Inflation Reduction Act of 2022, indicating their suitability for producing decarbonized hydrogen under this program.

Modeling and design of a combined electrified steam methane reforming-pressure swing adsorption process

Steam methane reforming (SMR) is the most widely used hydrogen (H2) production method, converting natural gas and steam into H2 and carbon dioxide (CO2). SMR is a mature industrial technology that burns fossil fuels to provide heat to the endothermic reforming reaction and to generate steam, which contributes to the production of greenhouse gas emissions. In order to reduce heating-based emissions, an electrically-heated steam methane reforming process has been proposed. Conventional SMR uses a packed bed catalyst and receives heat through radiation from hot flames in the surrounding furnace; on the other hand, an electrified SMR employs a washcoated catalyst, and is resistively-heated through the wall of the reactor coil. To gain further insight into the scalability of hydrogen production processes using electrically-heated reformers, this paper takes experimental data from an electrified reformer built at UCLA, extracts kinetic parameters, and uses these parameters to model and scale up a hydrogen production plant with a hydrogen production capacity of 231 kg/h (2607 Nm3/h). The simulated plant includes a reformer, two water gas shift reactors, pressure swing adsorption (PSA) for separation, and a heat exchange network to make steam for the reformer. A two-column-PSA process is dynamically modeled to output 99% H2 purity, and the pressures necessary for separation and H2 recovery are calculated using steady-state simulation data. A sensitivity analysis is conducted for the most energy-efficient H2 production conditions (e.g., operating pressure, heat flux), and CO2 production amounts are compared to a conventional SMR process, demonstrating that electrified SMR can potentially be a significantly cleaner alternative. The optimization of electrified reformers must target high mass and heat transfer along the full length of the reformer to achieve near full methane conversion that will minimize off-gas generation from the PSA unit.

Catalytic cracking of methane to hydrogen and carbon: Scale-up perspective

Decarbonizing natural gas for the production of H2 and value-added nanostructured graphitic carbons via catalytic decomposition of methane (CDM) presents an attractive alternative to conventional steam-methane reforming. This work is an attempt to establish the practical viability of the CDM process considering the reciprocity of methane conversion, the type and quantity of carbon formation, and the effective lifetime of the catalyst. Effects of the reaction parameters and reactor configurations on the catalyst performance, type of carbon-formation, and the catalyst degradation have been analyzed critically, providing state-of-the-art on laying a foundation for the development of new catalysts with better selectivity and longevity. Finally, a continuous regeneration-recycling system has been modeled by simulating a fluidized-bed reactor for Fe-based catalyst. The energy-exchange efficiency of regeneration/recirculation of catalyst via partial combustion has been established to lay out the guidelines for future development of the CDM process on a commercial-scale.

Life cycle environmental performance of methanol production through photocatalytic dry methane reforming

Photocatalytic dry methane reforming uses light energy and a nanostructured photocatalyst to convert both carbon dioxide and methane gas to syngas for production of fuels and value-added chemicals. The conversion of these two greenhouse gases (GHG) makes photocatalytic dry methane reforming a potentially environmentally attractive process; however, little research has been done to assess its life cycle environmental impacts in comparison to conventional commodity chemical production methods. Further, practical research has been limited to lab scale studies, which do not fully reflect the technical and environmental performance of commercial scale systems. In this work, a simulation describing the production of methanol from a photocatalytic dry reforming process is used to inform a life cycle assessment to estimate its potential environmental impacts at scale. Results indicate that for methanol produced via photocatalytic dry methane reforming to have the same life cycle GHG intensity as methanol produced through conventional steam methane reforming, a combination of improved technological performance and process intensification is required. This includes increased chemical conversion, electricity grid decarbonization, and the use of low greenhouse gas intensive feedstocks. Promisingly, results indicate that methanol produced using a photocatalytic dry methane reforming process that employs landfill gas as a feedstock and 100% renewable electricity, could potentially produce methanol with a negative global warming potential. Opportunities to improve the environmental impact of a photocatalytic dry reforming process so as to widen its scenario applicability are also discussed.

A novel on-site SMR process integrated with a hollow fiber membrane module for efficient blue hydrogen production: Modeling, validation, and techno-economic analysis

Steam methane reforming (SMR) is widely used in the hydrogen production industry; however, a significant amount of CO2 is released during this process. Several efforts have been made to produce low-CO2 hydrogen (blue hydrogen) via SMR; however, the proposed solutions are not applicable to small-scale plants. Therefore, this study proposes an on-site SMR process combined with a hollow fiber membrane module (HFMM) for CO2 capture in small-scale plants. First, mathematical models for the on-site SMR process and HFMMs were developed, and their accuracy was validated with real-world data. Second, we designed and implemented the SMR–HFMM model based on different operating conditions and gas compositions at three potential CO2 capture locations (dry syngas, PSA tail gas, and flue gas). The CO2 capture performances at these three locations were compared using five performance indicators: stage cut, separation factor, CO2 recovery rate, permeate composition, and retentate composition. Finally, to evaluate the integrated processes for each CO2 capture location, feasible ranges of the number of HFMMs and the levelized cost of hydrogen (LCOH) were calculated. In the case of CO2 captured in dry syngas, the number of HFMMs required to achieve a CO2 purity of over 90% was calculated to be 10–25. Furthermore, despite additional HFMM installation, the LCOH was 0.8%–1.5% lower than that of the conventional on-site SMR process that is 7.07–7.13 USD/kgH2. The proposed integrated SMR–HFMM process is a potential solution to the problem of CO2 emissions in on-site SMR processes with a lower LCOH. Therefore, the findings of this study could be of significant importance in improving the environmental sustainability of hydrogen production in small-scale plants.

Industrial hydrogen hub planning and operation with multi-scale optimisation

Hydrogen is a chemical product and energy carrier that, if used in the right way, could help decarbonise many sectors such as transportation, electricity production, the steel industry or petroleum refining. However, hydrogen’s versatility, which a strength in terms of energy transition, makes its deployment more complex to plan. This study provides a methodology aiming to understand the evolution of a local energy system including different coupled energy vectors: natural gas, biomethane, hydrogen and electricity. A bottom-up multi-vector linear optimisation provides some elements regarding the planning and hourly operation of hydrogen production and storage infrastructures. The methodology consists in three steps. First, hydrogen demand and the technical context is modelled by defining different evolution scenarios. Then, a first optimisation at the country scale is conducted in order to define the boundary conditions for the third step, where the local hydrogen ecosystem evolution is optimised. This methodology was used to study the evolution of the industrial harbour of Fos-sur-mer in south of France. The results show that electrolysis is expected to grow, replacing existing technologies such as conventional steam methane reforming (SMR). However, depending on the context, keeping the SMR as peak production capacities can bring more flexibility into the local system and thus; improve the competitiveness of hydrogen. For the studied industrial cluster in south of France, we found an average levelised cost of hydrogen of 2.9 €/kgH2 in a reference scenario. This value can decrease to 2.5 €/kgH2 in the most flexible case with large underground storage and go up to 4 €/kgH2 in the case where SMR are banned from 2030. If space is available on a local level, then the development of dedicated renewables together with electrolysis seems to be the optimal trajectory.

A novel moving bed chemical looping process with integration of combustor heat exchangers for hydrogen production: Process simulation and techno-economic analysis

In this study, using natural gas as the feedstock, a new scheme – a chemical looping combustion system with a moving bed reducer, coupled with the steam methane reforming (MCLC-SMR), is proposed and simulated for hydrogen production. This suggested process configuration is compared with other hydrogen production systems including the fluidized bed chemical looping combustion system coupled with the steam methane reforming (FCLC-SMR), the chemical looping partial oxidation system combined with the water-gas-shift reaction (CLPO-WGS), the 3-reactor chemical looping system for hydrogen generation (CLHG-3R), the conventional steam methane reforming (SMR) and auto-thermal reforming (ATR) systems with CO2 capture. The simulation results indicate that the particle circulation rate in MCLC-SMR is 64% less than in FCLC-SMR. MCLC-SMR also shows the best system performance regarding cold gas efficiency (79%) and effective thermal efficiency (75%). The economic assessment indicates that MCLC-SMR can achieve the lowest levelized cost of hydrogen (LCOH) of $1.34/kg at 30 ton/hr H2 production capacity, and CLHG-3R can achieve the lowest LCOH of $2.06/kg at 1 ton/hr H2 production capacity among the six hydrogen production methods. At 30 ton/hr H2 production capacity, the chemical looping reactors in MCLC-SMR are 37% cheaper than in FCLC-SMR. The sensitivity analysis also indicates that MCLC-SMR remains the most economical hydrogen production method over a wide range of price parameters (the prices of particles, chemical looping reactors, natural gas, and electricity).

Transition into Net-Zero Carbon Community from Fossil Fuels: Life Cycle Assessment of Light-Driven CO2 Conversion to Methanol Using Graphitic Carbon Nitride

Direct conversion of waste CO2 into CH3OH by solar irradiation has emerged as the most enthralling alternative to conventional steam methane reforming, which reduced the concentration of greenhouse gases and the consumption of fossil resources. A cradle-to-gate life cycle assessment was carried out to assess the environmental feasibility of implementing the current g-C3N4-based photocatalytic CO2 reduction system based on 1 kg CH3OH production. It was observed that the emerging photocatalytic CH3OH system induced 68 and 53% less carbon footprint and fossil usage, respectively, in producing the same amount of CH3OH as compared to the conventional approach. The CO2 reduction reaction step was identified as the main contributor in photocatalytic system, which accounted for more than 50% of the total environmental impact scores. In the conventional system, the score points of global warming and fossil depletion contributed the most by the product purification and desulfurization step, respectively. In addition, sensitivity analysis manifested that the lowest environmental burden of 46.50 kg of CO2 equiv carbon emission and 15.27 kg oil equiv fossil consumption was obtained in the photocatalytic CH3OH system upon replacing fossil-based energy with hydro-powered electricity. These results suggest a potent replacement of the incumbent industry system for the amelioration of climate benefits and resource conservation with the advanced development of the photocatalytic system.

Carbon-neutral hydrogen production from natural gas via electrified steam reforming: Techno-economic-environmental perspective

This study proposes and evaluates a novel carbon-neutral hydrogen (H2) production process from natural gas through electrified steam methane reforming (e-SMR) with renewable electricity. The process model consists of different unit technologies such as reforming, water–gas shift, hydrogen pressure swing adsorption, and CO2 capture, along with heat recovery. Then, we evaluated the techno-economic-environmental performance of the proposed e-SMR process by comparing it with the conventional fired-heating steam methane reforming (f-SMR). By employing an electrically driven reformer using renewable energy, e-SMR outperforms f-SMR with less natural gas consumption, higher energy efficiency of 78.7%, and lower net CO2eq emission of 5.28 kg CO2eq/kg H2 and captured 5.58 kg CO2/kg H2; however, it has a drawback, i.e., higher H2 unit production cost (UPC) of 3.49 $/kg with a capacity of 7.06 ton/day. Sensitivity and uncertainty analyses identified the major cost drivers of UPC, such as the prices of natural gas, renewable electricity, and interest rates, as well as economic risks and uncertainties. The economic viability of e-SMR was determined by investigating multiple plant capacities, natural gas markets, renewable energy prices, and possible future CO2 selling prices. According to the investigation, currently, the US and India show promise for e-SMR, with abundant and affordable natural gas and renewable energy resources, both priced at around 3.49 $/kg of H2, respectively. Furthermore, the global 2030's scenario with 45 $/MWh of renewable electricity, and capture CO2 credit of 35 $/ton is observed at 3.40 $/kg H2, compared with that of 2050 at 2.91 $/kg H2. e-SMR is well adaptable to many countries' energy mix because it is flexible to utilize hybrid primary energy input, conventional natural gas as feedstock, and conventional/renewable energy for utilities.

Investigating the techno-economic and environmental performance of chemical looping technology for hydrogen production

There is limited research assessing the techno-economic feasibility and environmental footprint of direct partial oxidation of methane using chemical looping technology for hydrogen production. The available studies have not investigated essential aspects of the impact of hydrogen storage cost or economies of scale on hydrogen production cost. In this study, process models were developed based on fundamental science for hydrogen production using chemical looping technology. The results show that for a production plant capacity of 607 tonnes/day, the hydrogen cost is $3.66/kg. When the uncertainty in the input parameters is considered, the hydrogen cost ranges from 3.51 to 4.70 $/kg. The parameters that most influence hydrogen cost are discount rate and hydrogen storage. The hydrogen cost versus capacity profile shows that operating chemical looping at a higher capacity is financially beneficial because of economies of scale. The developed scale factor is 0.64. The net energy ratio is 0.84, indicating chemical looping is a better energy producer than the traditional method of hydrogen production, i.e., steam methane reforming. The greenhouse gas emissions are 2.86 kgCO2/kg-H2. The results show that chemical looping partial oxidation of methane provides better energy efficiency and a better environmental footprint than conventional steam methane reforming.

Comparative techno-economic and life cycle greenhouse gas assessment of ammonia production from thermal decomposition of methane and steam methane reforming technologies

This study assesses the life cycle greenhouse gas (GHG) and economic feasibility of applying thermal decomposition of methane (TDM) technology for ammonia production compared to the conventional steam methane reforming (SMR) technology. A detailed process model for each ammonia-based technology was developed to get data to perform energy, life cycle GHG emissions, and economic analyses. The results showed that the SMR plant consumes 30.3% more fuel than the TDM. The life cycle GHG emissions of TDM and SMR are 1.42 and 2.51 t CO2e/t NH3, respectively. The combustion and process emissions released to the environment and electricity emissions take a large share in the life cycle emissions of SMR and TDM, respectively. The production cost of ammonia from SMR is lower than TDM by $69/t NH3. TDM requires a higher investment because of high capital costs and the huge amount of natural gas needed as feedstock. For TDM, the sale of the oxygen product does not provide sufficient revenue to outperform SMR. However, integrating a carbon capture unit into TDM makes it economic performance better than SMR (with a carbon capture unit) when the sale of oxygen is considered. The results also showed that SMR (without carbon capture unit) is more economically attractive when the carbon price benchmark is below $99/t CO2. Above this carbon price, integrating a carbon capture unit into TDM is economically preferable.

Blue, green, and turquoise pathways for minimizing hydrogen production costs from steam methane reforming with CO2 capture

Rising climate change ambitions require large-scale clean hydrogen production in the near term. “Blue” hydrogen from conventional steam methane reforming (SMR) with pre-combustion CO2 capture can fulfil this role. This study therefore presents techno-economic assessments of a range of SMR process configurations to minimize hydrogen production costs. Results showed that pre-combustion capture can avoid up to 80% of CO2 emissions cheaply at 35 €/ton, but the final 20% of CO2 capture is much more expensive at a marginal CO2 avoidance cost around 150 €/ton. Thus, post-combustion CO2 capture should be a better solution for avoiding the final 20% of CO2. Furthermore, an advanced heat integration scheme that recovers most of the steam condensation enthalpy before the CO2 capture unit can reduce hydrogen production costs by about 6%. Two hybrid hydrogen production options were also assessed. First, a “blue-green” hydrogen plant that uses clean electricity to heat the reformer achieved similar hydrogen production costs to the pure blue configuration. Second, a “blue-turquoise” configuration that replaces the pre-reformer with molten salt pyrolysis for converting higher hydrocarbons to a pure carbon product can significantly reduce costs if carbon has a similar value to hydrogen. In conclusion, conventional pre-combustion CO2 capture from SMR is confirmed as a good solution for kickstarting the hydrogen economy, and it can be tailored to various market conditions with respect to CO2, electricity, and pure carbon prices.

Flexible methanol production process using biomass/municipal solid waste and hydrogen produced by electrolysis and natural gas pyrolysis

Biomass-derived liquid fuels with low greenhouse gas emissions are an integral part of decarbonization plans. Three pathways for enhancing production of methanol from biomass and municipal solid waste (MSW), natural gas, and renewable electricity are explored using hydrogen produced from water electrolysis, natural gas pyrolysis, or combinations of these inputs. A combined electrolysis and natural gas pyrolysis process is designed to be flexible, changing operation modes depending on the cost of feedstocks (i.e. electricity and natural gas). A techno-economic analysis is performed to assess and compare the economic attractiveness of these processes. Hydrogen produced from natural gas pyrolysis could potentially be more economically attractive than electrolytic hydrogen using renewable electricity. Moreover, natural gas pyrolysis CO2 emissions could be substantially lower than emissions from conventional steam methane reforming (e.g., CO2 emissions which are 25 % or lower compared to CO2 emission from steam methane reforming). Hydrogen enhancement of the methanol production process results in increase of around a factor of two in carbon conversion efficiency (e.g. from 44% to 94 %). Methane pyrolysis shows high economic potential assuming the technical challenges to its commercialization are successfully addressed. Given an installed cost of electrolyzer of 1000 $/kW, electricity price of 50 $/MWh, natural gas price of 5 $/GJ and 100 $/ton selling price of carbon black, the natural gas pyrolysis design results in the lowest methanol production cost. Our analysis indicates that methanol could be produced in a price range of 300–1000$/ton depending on feedstock price (particularly electricity) and the chosen process.

Hydrogen production using piston reactor technology: Process design and integration for CO2 emission reduction

The piston reactor is emerging as a simple, inexpensive, and compact technology to carry out chemical reactions. Potential piston reactor advantages include high temperature and pressure conditions at short residence times, large throughput, and fast quenching steps. Published research related to hydrogen production using piston reactors has almost exclusively focused on the POX route for hydrogen production and on exploring reactor performance as opposed to overall process performance in terms of specific production costs and emissions. This study provides a process-level understanding of the techno-economics of hydrogen production using piston reactor technology via the three prominent routes for grey and blue hydrogen production: methane partial oxidation (POX), auto-thermal reforming (ATR), and steam methane reforming (SMR). A piston reactor model is initially used to screen the reactor performance in terms of methane conversion and hydrogen production, revealing underperformance for the SMR route. Next, stand-alone hydrogen production processes embedding the piston reactors for the remaining POX and ATR routes are synthesized and specific production costs and CO2 emissions for ‘grey’ hydrogen production determined. Next, the piston reactor processes are integrated with CO2 capture and compression steps for subsequent sequestration and the impact of such CO2 emission mitigation on ‘blue’ hydrogen production costs is evaluated. The obtained results show that the piston-reactor ATR process significantly outperforms the piston-reactor POX process for both grey and blue hydrogen production. For a 100 TPD plant capacity and a natural gas price of $3.3/GJ, blue hydrogen production costs for the piston reactor-based ATR processes are observed to be 1.6/kg H2, which is competitive with reported blue hydrogen production costs using the conventional SMR route. A sensitivity study reveals that the plant capacity has significant impact while piston reactor useful life had low impact hydrogen production costs.

Plasma steam methane reforming (PSMR) using a microwave torch for commercial-scale distributed hydrogen production

Although large-scale hydrogen production through conventional steam methane reforming (SMR) is available at an affordable cost, there is a shortage of hydrogen pipeline infrastructure between production plants and fueling stations in most places where hydrogen is needed. Due to the difficulties of transporting and storing hydrogen, onsite hydrogen production plants are desirable. Microwave plasma torch-based methods are among the most promising approaches to achieving this goal.The plasma steam methane reforming (PSMR) method discussed here has many benefits, including a high energy yield, a small carbon footprint, real-time fueling because of the short start-up time (<10 min), and the absence of expensive metal-based catalysts. Methane reforming and water gas shift reaction (WGSR) co-occur in the method advanced without a separate WGSR to achieve a high H2 yield.This study examines an experimental investigation of commercial-scale hydrogen production through PSMR utilizing a microwave torch system. The optimum results obtained showed that the hydrogen production rate was 2247 [g(H2)/h], and energy yield was 70 [g(H2)/kWh] of the absorbed microwave power. An assessment of the results indicated a similar trend to that of simulated data (ASPEN Plus). The experimental results presented in this paper demonstrate the potential of a catalyst-free PSMR for commercial-scale hydrogen production.

Techno-economic assessment of solar steam reforming of methane in a membrane reactor using molten salts as heat transfer fluid

This paper reports the results obtained in a techno-economic analysis of the Steam Methane Reforming (SMR) technology aided with solar heat, developed and demonstrated in the European FCH JU project CoMETHy: a compact membrane reformer heated with molten salt up to 550 °C allowed to simultaneously carry out methane steam reforming, water-gas-shift reaction and hydrogen separation. This reactor can be integrated with new generation Concentrating Solar Thermal (CST) systems to supply the process heat. Experimental validation of the technology has been successfully achieved in a pilot scale plant and the results recently published. In this paper, we introduce a fully-integrated scheme and operation strategies of a plant on the 1500 Nm3/h hydrogen production scale. Then, techno-economic analysis of this new solar-driven process is presented to evaluate its competitiveness. Considering a plant capacity of 1500 Nm3/h (pure hydrogen production) and today's costs for the methane feed and the CST technology, obtained Hydrogen Production Cost (HPC) are in the range of 2.8–3.3 €/kg for a “solar-hybrid” system with high capacity factor (8000 h/year operation) and 4.7 €/kg for a “solar-only” case, while HPC≅1.7 €/kg can be obtained with the conventional route under equivalent assumptions. However, a sensitivity analysis shows that the expected drop of the cost of the CST technology will bring the HPC around 2.4 €/kg for the “solar-hybrid” case and close to 3.4 €/kg for the “solar-only” case, thus making the cost of solar reforming closer to conventional SMR with CO2 capture and with wind/solar electrolysis in the future. In the “solar-hybrid” case total CO2 production can be reduced by 13–29% with 58–70% of produced CO2 recovered as pure stream (at 1.3 bar); in the “solar-only” case total CO2 production can be reduced by 52% and 100% of produced CO2 recovered as pure stream (at 1.3 bar). However, compared to the conventional route, CO2 avoidance costs are still relatively high (≥137 €/tonCO2) and process optimization measures required. Therefore, optimization measures have been outlined to increase the overall process efficiency and further reduce the HPC.

Comparative analysis of conventional steam methane reforming and PdAu membrane reactor for the hydrogen production

A comparison study between conventional and PdAu-based membrane steam methane reforming (SMR) processes for small-scale hydrogen production was conducted. Both processes were simulated using a commercial simulation software Aspen Plus. For the PdAu-based membrane reactor, a 1D pseudo-homogenous model was developed via Aspen Custom Modeler (ACM). The optimum operating pressure and temperature for the membrane SMR process are 30 bar and 550˚C. While the conventional SMR process has higher performance operating at 23 bar and 900˚C at the reforming reactor outlet. The simulation results revealed that the membrane SMR process has higher methane conversion, hydrogen yield, and process energy efficiency than the conventional SMR process. Moreover, cost analysis was conducted for both processes to study their economic feasibility. The analysis revealed that hydrogen production costs for conventional and membrane SMR processes are 4.54 and 2.87 $/kg H2 respectively.

Comprehensive process and environmental impact analysis of integrated DBD plasma steam methane reforming

Utilization of electricity generated from renewable sources to obtain hydrogen, H2, is of critical importance to decrease the overall carbon footprint. In this work, integration of a dielectric discharge barrier (DBD) plasma reactor to convert low calorific value gas, such as landfill gas or coal mine gas into hydrogen, into the existing steam methane reforming (SMR) technology was evaluated using process design considerations. In particular, a DBD-enhanced catalytic SMR reactor was modeled to operate at near atmospheric pressure and 500 °C sequentially with the conventional reformer to obtain ~ 65 kmol/hr H2 for distributed production. This allowed decreasing the size of the conventional reformer albeit at the increased overall electricity consumption. Calculated process economics showed that only at an electricity cost of less than $0.004/kWh does the hybrid DBD plasma process derived H2 price become competitive with that of the conventional SMR. A Life Cycle Assessment framework was used to compare environmental impacts from the conventional SMR, hybrid DBD SMR and hybrid DBD SMR utilizing only onshore wind-derived electricity. Larger environmental impacts in the plasma reformer were obtained due to the use of electricity for the plasma reforming operation, which was modeled as coming from the typical U.S. grid mix. Utilizing only 100% wind-derived electricity provided certain environmental benefits, except for the ecotoxicity impact where the wind power scenario modeled here only reduced ecotoxicity impacts associated with electricity by 30%.

The Potential of Gas Switching Partial Oxidation Using Advanced Oxygen Carriers for Efficient H2 Production with Inherent CO2 Capture

The hydrogen economy has received resurging interest in recent years, as more countries commit to net-zero CO2 emissions around the mid-century. “Blue” hydrogen from natural gas with CO2 capture and storage (CCS) is one promising sustainable hydrogen supply option. Although conventional CO2 capture imposes a large energy penalty, advanced process concepts using the chemical looping principle can produce blue hydrogen at efficiencies even exceeding the conventional steam methane reforming (SMR) process without CCS. One such configuration is gas switching reforming (GSR), which uses a Ni-based oxygen carrier material to catalyze the SMR reaction and efficiently supply the required process heat by combusting an off-gas fuel with integrated CO2 capture. The present study investigates the potential of advanced La-Fe-based oxygen carrier materials to further increase this advantage using a gas switching partial oxidation (GSPOX) process. These materials can overcome the equilibrium limitations facing conventional catalytic SMR and achieve direct hydrogen production using a water-splitting reaction. Results showed that the GSPOX process can achieve mild efficiency improvements relative to GSR in the range of 0.6–4.1%-points, with the upper bound only achievable by large power and H2 co-production plants employing a highly efficient power cycle. These performance gains and the avoidance of toxicity challenges posed by Ni-based oxygen carriers create a solid case for the further development of these advanced materials. If successful, results from this work indicate that GSPOX blue hydrogen plants can outperform an SMR benchmark with conventional CO2 capture by more than 10%-points, both in terms of efficiency and CO2 avoidance.