Coal-based Hydrogen Research Articles

Measuring the global warming potential of polygeneration in coal-based hydrogen systems

Measuring the global warming potential of polygeneration in coal-based hydrogen systems

Utilization of coal for hydrogen generation

ABSTRACT The utilization of coal for hydrogen generation presents a multifaceted approach employing processes like coal gasification, pyrolysis, or high-temperature steam reforming. These methodologies entail reacting coal with steam or oxygen under elevated temperatures, yielding a gas mixture comprising hydrogen, carbon monoxide, and various byproducts. This paper delves into the exploration of hydrogen generation from coal, highlighting techniques such as gasification, pyrolysis, and other emerging methods. Notably, hydrogen discoveries within coal basins have garnered significant attention due to their implications for energy production and environmental sustainability. Certain coal basins harbor deposits rich in hydrogen, surpassing conventional coal reserves in their hydrogen content. These hydrogen-rich coals, including select sub-bituminous and lignite varieties, offer promising avenues for hydrogen production and utilization. However, the utilization of coal for hydrogen generation is not without its challenges. Technical hurdles, such as process efficiency and environmental concerns, demand rigorous investigation and innovative solutions. This paper addresses the challenges faced in coal-based hydrogen generation while elucidating the potential future prospects. It explores avenues for enhancing process efficiency, mitigating environmental impacts, and integrating coal-based hydrogen generation into broader energy strategies. Moreover, it underscores the importance of interdisciplinary research and collaboration in unlocking the full potential of coal for sustainable hydrogen production.

Subsidizing Grid-Based Electrolytic Hydrogen Will Increase Greenhouse Gas Emissions in Coal Dominated Power Systems.

Clean hydrogen has the potential to serve as an energy carrier and feedstock in decarbonizing energy systems, especially in "hard-to-abate" sectors. Although many countries have implemented policies to promote electrolytic hydrogen development, the impact of these measures on costs of production and greenhouse gas emissions remains unclear. Our study conducts an integrated analysis of provincial levelized costs and life cycle greenhouse gas emissions for all hydrogen production types in China. We find that subsidies are critical to accelerate low carbon electrolytic hydrogen development. Subsidies on renewable-based hydrogen provide cost-effective carbon dioxide equivalent (CO2e) emission reductions. However, subsidies on grid-based hydrogen increase CO2e emissions even compared with coal-based hydrogen because grid electricity in China still relies heavily on coal power and likely will beyond 2030. In fact, CO2e emissions from grid-based hydrogen may increase further if China continues to approve new coal power plants. The levelized costs of renewable energy-based electrolytic hydrogen vary among provinces. Transporting renewable-based hydrogen through pipelines from low- to high-cost production regions reduces the national average levelized cost of renewables-based hydrogen but may increase the risk of hydrogen leakage and the resulting indirect warming effects. Our findings emphasize that policy and economic support for nonfossil electrolytic hydrogen is critical to avoid an increase in CO2e emissions as hydrogen use rises during a clean energy transition.

Conceptual design and assessment of Integrated capture and methanation of CO2 from flue gas using chemical-looping scheme of dual function materials

Integrated Carbon Capture and Methanation (ICCM) with renewable hydrogen is considered a promising Power-to-Gas technology. Although ICCM is expected to reduced CO2 emission, the potentials of net CO2 reduction and economic feasibility are still unrevealed by careful assessments. This study developed three ICCM processes at industrial scale, and performed an assessment in terms of energy conversion efficiency, comprehensive energy consumption, net CO2 emission, and levelized cost of CO2 conversion. Special attentions were paid to investigate the effects from electricity and hydrogen sources, and plant configuration on the technical, environmental, and economic feasibilities. This work also identified the opportunities and challenges as operation pressure, SNG price, and carbon tax are consideredthe primary factors. A comparison was made between ICCM processes and the reference process that combines CO2 capture with aqueous solutions and CO2 catalytic hydrogenation for CH4 fuels. 89.0 % of energy conversion efficiency could be achieved with ICCM processes, much higher than that of reference process. When ICCM processes are driven by renewable energy, the best comprehensive energy consumption is estimated to be –20.68 MJ/kg CO2; negative CO2 emissions could be easily achieved for ICCM processes, and the best net CO2 emissions is –1.57 kg CO2/kg CO2 when powered by wind energy, demonstrating the technical and environmental feasibility as ICCM process is coupled with renewable energy. The levelized costs of CO2 conversion are in the range of 0.98–2.0 US$/kg CO2. The economic feasibility of ICCM process is primarily limited by H2 production cost. But the levelized costs of CO2 conversion decreases rapidly with H2 production cost, and the ICCM processes could become profitable if the cost of H2 production from renewable energy drops to the same level of coal-based hydrogen (<1.4 US$/kg H2). It is possible for European Union to deploy ICCM plants to bring economic revenues because of its high SNG price and carbon tax.

Technical and economic analysis of different colours of producing hydrogen in China

This paper explores the different types of hydrogen production by exploring them and giving each a different colour. From dark to money in descending order, they represent a gradual reduction in pollution. The basic principles, advantages and disadvantages of the respective production methods are explored at a technical level. The learning curve theory calculates the individual learning rates for different hydrogen production methods to increase the installed capacity while reducing the capital investment and cost of hydrogen production. The study concludes that coal-based hydrogen production is currently the primary method of hydrogen production in China in the short term due to its high resource endowment of coal. As CCUS technology matures, converting brown hydrogen to blue hydrogen and grey hydrogen to turquoise hydrogen are the two more economically viable options. For the cleanest form of green hydrogen, the fundamental problems are the impediments of electrolyser technology (PEM, SOEC cannot be commercialised) and the high wind and photovoltaic power cost. The solution is to use wind and light abandonment to increase hydrogen production in the short term and replace fossil energy with renewable energy generation in the long term to achieve clean hydrogen production. For hydrogen energy, the vigorous development of hydrogen fuel cell vehicles and the massive reduction of greenhouse gas emissions in transport is essential to achieving carbon neutrality while ensuring the supply of hydrogens such as blue hydrogen and green hydrogen.

The carbon footprint and cost of coal-based hydrogen production with and without carbon capture and storage technology in China

CCS (CO 2 capture and storage) technology provides technical support for low-carbon hydrogen production from coal. This study evaluates the carbon footprint and cost of coal-based hydrogen production with and without CCS in China by introducing provincial coal prices and electricity prices, as well as the life cycle greenhouse gas emission factor for consumed electricity. The results show that the carbon footprint of coal to hydrogen is reduced by 52.34%–74.59% to 4.92–10.90 CO 2 eq/kg H 2 after installing CCS technology, which is close to that of solar electricity-based hydrogen production. In addition, CCS increases the cost by 44.59%–60.84% to 1.44–2.11 USD/kg H 2 , but it does not deprive the cost advantage of hydrogen production from coal over renewable electricity-based hydrogen production. Therefore, China should promote the development of coal to hydrogen with CCS to meet the growing demand for hydrogen, at least before there is a breakthrough in hydrogen production from renewable electricity. West China may be the preferred option for future new coal to hydrogen plants, where the cost of coal to hydrogen with CCS is lower than that of other regions. Of course, other complex factors, such as the regional distribution of demand, must be considered to truly determine the site. In addition, coal-to-hydrogen plants in Inner Mongolia, Xinjiang and Shaanxi Provinces, with low hydrogen production costs , strong carbon constraints and low CCS costs, should be the priority option for early CCS projects in China. • The carbon footprint of coal to hydrogen without CCS is 19.37–22.87 CO 2 eq/kg H 2 . • CCS technology can reduce the carbon footprint by 52.34%–74.59%. • The cost of coal to hydrogen without CCS is 0.90–1.46 USD/kg H 2 . • The installation of CCS will increase the cost by 44.59%–60.84%.

Identifying the key development areas for small nuclear power plants

The paper considers the key characteristics of the small nuclear power plant (SNPP) modular design, demonstrates the possibility for reducing the construction cost and time for this class of plants due to factory fabrication, the effect of series manufacturing, and less redundant safety systems. It has been shown that it is possible to extend considerably the fields of application for nuclear technologies thanks to modularity and the possibility of ensuring high safety indicators. Potential applications for SNPPs have been analyzed, including power supply to remote (Arctic) territories, switchover from (renovation of) coal-based electricity generation, high-potential heat and hydrogen production for commercial consumers, and other applications. Rationale has been provided for most typical consumer requirements that define the greatest efficiency of the SNPP application in the given field. The need has been shown for developing and introducing a new technology platform for the SNPP-based nuclear power to decarbonize globally the world economy thanks to expanding greatly the application of nuclear power technologies in addition to the technology platform currently developed for the CNFC with fast reactors (addressing the objective of fuel supply and waste recycling) and the controlled nuclear fusion technology platform (addressing the objective of long-term global energy supply). The new platform needs to be based on an extensive international cooperation involving the formation of international consortiums. It has been proposed that a test site be set up to elaborate hydrogen (heat) production technologies for an individual commercial consumer (captive production) and other technologies for the practical use of SNPPs based on a pilot demonstration nuclear power plant.

Environmental and energy implications of coal-based alternative vehicle fuel pathway from the life cycle perspective.

Coal-based fuels are effective alternative vehicle fuels in coal-rich countries, but whether it is beneficial to the environment and carbon neutrality has always been a concern. This study evaluates the energy efficiency, greenhouse gas (GHG) emissions, water footprint (WF), and environmental impact of coal-based diesel, coal-based synthetic natural gas, coal-based hydrogen, and coal-based electricity pathways from the life cycle perspective. Furthermore, scenario analysis predicts the impact of coal-rich countries on energy and emissions by adjusting vehicle fuel ratio. The results show that the coal-based diesel fuel pathway has lower energy efficiency and emits more GHGs. And GHGs are concentrated in fuel production stage. In terms of WF, the coal-based electricity pathway has the greatest benefits, which gray WF is dominant. From environmental impact perspective, a single vehicle fuel pathway cannot satisfy all impact categories. But the coal-based electricity pathway has the lowest value for the end-point environmental impact categories. Scenario analysis shows that the USA, India, and the European Union can significantly save energy and water resources and reduce GHG emissions with the increase in the proportion of alternative fuel vehicle in 2030. However, even a complete ban on the use of conventional gasoline vehicle in Norway will not reduce water consumption.

A novel hydrogen production system based on the three-step coal gasification technology thermally coupled with the chemical looping combustion process

Coal gasification technology is a significant process for the coal-based hydrogen production system and is considered as a key technology in the transition to “Hydrogen Economy”. To decrease the exergy destruction and enhance the cold gas efficiency of the coal gasification process, a novel three-step gasification technology thermally coupled with the chemical looping combustion process is proposed. And the hydrogen production system with CO2 recovery is integrated based on the three-step gasification technology. Results indicated that the cold gas efficiency of the three-step coal gasification technology is 86.9%, which is 10.1% points enhanced compared with GE gasification technology. Besides, the novel system has an energy efficiency of 62.3%, which is 3.1% higher than that of the reference system. Exergy analysis presented that the employment of the three-step gasification technology contributed to the reduction of system exergy destruction by 4.2%. Furthermore, the energy utilization diagram (EUD) suggested that matching between endothermic reactions and exothermic reactions plays important role in the enhancement of cold gas efficiency.

PEMFC application through coal gasification along with cost-benefit analysis: A case study for South Africa

The availability of cost-effective and environmentally friendly electricity to the entire population is a prime concern of the South African government. It has brought attention to microgrid projects, especially when rural population is considered properly. To address the energy needs of any country, the focus line should be the cost and availability of local resources. Due to the abundance of coal reserves and lack of alternative resources, coal dependence cannot be overlooked in the near future. This paper focuses not only on microgrid needs in South Africa but also on the possible use of hydrogen extracted from coal as a fuel in Proton Exchange Membrane Fuel Cell (PEMFC) in microgrids. The complete assembly of PEMFC and its use in the microgrid are discussed. To make the H2 extraction process eco-friendly and hence worth considering, Carbon capture and sequestration process is discoursed. Furthermore, cost benefit analysis and the long term benefit of the use of PEMFC in microgrids with coal-based hydrogen production are presented in this research.

Multi-technique integration separation frameworks after steam reforming for coal-based hydrogen generation

Coal-based H 2 generation has abruptly increased in recent years. The PSA-VPSA-SC process is the matured and standard framework for H 2 purification and CO 2 capture in many existing plants, including normal and vacuum pressure swing adsorption units in series (PSA-VPSA), and shallow condensation unit (SC). However, this standard process is frequently subjected to low H 2 recovery ratio and high purification cost. In this work, H 2 -selective and CO 2 -selective membrane units, i.e. , HM and CO2M, are attempted to support the standard process and ameliorate constraints. In the beginning, HM unit is arranged after VPSA to enhance H 2 recovery from the decarbonized stream, i.e. , the PSA-VPSA-SC/HM process. As a result, H 2 recovery ratio can be enhanced significantly from 83% to 98%. In the following, VPSA is replaced with CO2M unit to reduce investment and operation cost, i.e. , the PSA-CO2M-SC/HM process. Accordingly, the specific purification cost is diminished from 33.46 to 32.02 USD·(10 3 m 3 H 2 ) −1 , saved by 4.3%, meanwhile the construction cost is falling back and just a little higher than that for the standard process. In the end, another CO2M unit is launched before PSA, i.e. , the CO2M-PSA-CO2M-SC/HM process, which could unbundle CO 2 enrichment partially from H 2 purification, and then save more investment and operation cost. In comparison with the standard process, this ultimate retrofitted process can be superior in all the three crucial indices, i.e. , recovery ratio, investment, and specific purification cost. On the whole, coal-based H 2 generation can be ameliorated significantly through high efficient H 2 -selective and CO 2 -selective membrane units.

Efficiency evaluation of a sustainable hydrogen production scheme based on super efficiency SBM model

The hydrogen production transition from coal to renewable energy is key to realize low-carbon in the whole hydrogen energy system. To accelerate the transition, this study proposes a sustainable hydrogen production scheme combining coal-based hydrogen production with renewable hydrogen production. Specifically, the excess alkalinity generated by water electrolysis can capture the CO2 from coal-based hydrogen production. Additionally, the oxygen generated by water electrolysis can be provided for coal-based hydrogen production. Different from previous studies, we use the super efficiency SBM model with undesirable outputs to calculate the efficiency of coal-based hydrogen production, renewable hydrogen production and the integrated scheme. Results show that the efficiency of the integrated scheme with the reasonable configuration is 2.01. And it has the highest efficiency ranking, followed by coal-based hydrogen production and hydrogen production from wind energy, which are 1.07 and 0.84, respectively. On the other hand, the hydrogen production from solar energy is 0.32, which has the lowest ranking. Therefore, the integrated scheme can provide the low-carbon hydrogen by the inexpensive cost. Popularizing the integrated scheme should promote the large-scale of renewable hydrogen production, thereby guiding the green transformation of hydrogen production.

Study on critical technologies and development routes of coal-based hydrogen energy

Abstract Hydrogen is considered a secondary source of energy, commonly referred to as an energy carrier. It has the highest energy content when compared to other common fuels by weight, having great potential for further development. Hydrogen can be produced from various domestic resources but, based on the fossil resource conditions in China, coal-based hydrogen energy is considered to be the most valuable, because it is not only an effective way to develop clean energy, but also a proactive exploration of the clean usage of traditional coal resources. In this article, the sorption-enhanced water–gas shift technology in the coal-to-hydrogen section and the hydrogen-storage and transport technology with liquid aromatics are introduced and basic mechanisms, technical advantages, latest progress and future R&amp;D focuses of hydrogen-production and storage processes are listed and discussed. As a conclusion, after considering the development frame and the business characteristics of CHN Energy Group, a conceptual architecture for developing coal-based hydrogen energy and the corresponding supply chain, is proposed.

Techno-Economic Analysis of Coal-Based Hydrogen and Electricity Cogeneration Processes with CO2 Capture

The techno-economic performances of various coal-based hydrogen and electricity cogeneration processes are examined under a carbon-constrained scenario. The baseline coal gasification process and the novel membrane and syngas chemical-looping processes are evaluated. Aspen Plus simulation is first performed to analyze the process efficiencies on the basis of a common set of assumptions. This is followed by economic analysis using the cost analysis principles suggested by the U.S. Department of Energy [Cost and Performance Baseline for Fossil Energy Plants, 2007]. The results indicate that the novel membrane and syngas chemical-looping strategies have the potential to notably reduce the energy and cost penalties for CO2 capture in coal conversion processes.

A Novel Coal-Based Hydrogen Production System With Low CO2 Emissions

In this paper, we have proposed a novel coal-based hydrogen production system with low CO2 emission. In this novel system, a pressure swing adsorption H2 production process and a CO2 cryogenic capture process are well integrated to gain comprehensive performance. In particular, through sequential connection between the pressure swing absorption (PSA) H2 production process and the CO2 capture unit, the CO2 concentration of PSA purge gas that enters the CO2 capture unit can reach as high as 70%, which results in as much as 90% of CO2 to be separated from mixed gas as liquid at a temperature of −55°C. This will reduce the quantity and quality of cold energy required for cryogenic separation method, and the solidification of CO2 is avoided. The adoption of cryogenic energy to capture CO2 enables direct production of liquid CO2 at low pressure and thereby saves a lot of compression energy. Besides, partial recycle of the tail gas from CO2 recovery unit to PSA inlet can help enhance the amount of hydrogen product and lower the energy consumption for H2 production. As a result, the energy consumption for the new system’s hydrogen production is only 196.8 GJ/tH2 with 94% of CO2 captured, which is 9.2% lower than that of the coal-based hydrogen production system with Selexol CO2 removal process and is only 2.6% more than that of the coal-based hydrogen production system without CO2 recovery. More so, the energy consumption of CO2 recovery is expected to be reduced by 20–60% compared with that of traditional CO2 separation processes. Further analysis on the novel system indicates that synergetic integration of the H2 production process and cryogenic CO2 recovery unit, along with the synthetic utilization of energy, plays a significant role in lowering energy penalty for CO2 separation and liquefaction. The promising results obtained here provide a new approach for CO2 removal with low energy penalty.

Oil and natural gas prices and greenhouse gas emission mitigation

The hikes in hydrocarbon prices during the last years have lead to concern about investment choices in the energy system and uncertainty about the costs for mitigation of greenhouse gas emissions. On the one hand, high prices of oil and natural gas increase the use of coal; on the other hand, the cost difference between fossil-based energy and non-carbon energy options decreases. We use the global energy model TIMER to explore the energy system impacts of exogenously forced low, medium and high hydrocarbon price scenarios, with and without climate policy. We find that without climate policy high hydrocarbon prices drive electricity production from natural gas to coal. In the transport sector, high hydrocarbon prices lead to the introduction of alternative fuels, especially biofuels and coal-based hydrogen. This leads to increased emissions of CO 2. With climate policy, high hydrocarbon prices cause a shift in electricity production from a dominant position of natural gas with carbon capture and sequestration (CCS) to coal-with-CCS, nuclear and wind. In the transport sector, the introduction of hydrogen opens up the possibility of CCS, leading to a higher mitigation potential at the same costs. In a more dynamic simulation of carbon price and oil price interaction the effects might be dampened somewhat.

Greenhouse gas implications of using coal for transportation: Life cycle assessment of coal-to-liquids, plug-in hybrids, and hydrogen pathways

Using coal to produce transportation fuels could improve the energy security of the United States by replacing some of the demand for imported petroleum. Because of concerns regarding climate change and the high greenhouse gas (GHG) emissions associated with conventional coal use, policies to encourage pathways that utilize coal for transportation should seek to reduce GHGs compared to petroleum fuels. This paper compares the GHG emissions of coal-to-liquid (CTL) fuels to the emissions of plug-in hybrid electric vehicles (PHEV) powered with coal-based electricity, and to the emissions of a fuel cell vehicle (FCV) that uses coal-based hydrogen. A life cycle approach is used to account for fuel cycle and use-phase emissions, as well as vehicle cycle and battery manufacturing emissions. This analysis allows policymakers to better identify benefits or disadvantages of an energy future that includes coal as a transportation fuel. We find that PHEVs could reduce vehicle life cycle GHG emissions by up to about one-half when coal with carbon capture and sequestration is used to generate the electricity used by the vehicles. On the other hand, CTL fuels and coal-based hydrogen would likely lead to significantly increased emissions compared to PHEVs and conventional vehicles using petroleum-based fuels.

Laboratory scale tests of coal-based hydrogen production with CO&lt;SUB align=right&gt;2 capture in the aspect of clean coal technologies

In the light of continuously increasing oil prices as well as stronger environmental regulations, an important issue becomes finding an alternative to fossil fuels. Scientists agree that hydrogen seems to be an ideal, price-competitive and environment-friendly future energy carrier. One of the most effective methods of hydrogen production is the process of steam gasification of coal to hydrogen-rich gas. In this paper the results of laboratory tests of steam gasification of coal oriented on hydrogen-rich gas production with CO2 capture are presented. The coal samples used in the experiments were provided by the Polish coal mine Piast. The tests were conducted in a vertical fixed-bed reactor system in a temperature range of 923-1173 K. The idea of the hydrogen-rich gas production process was based on the simultaneous use of iron oxide as an oxygen-transfer compound that enhances the conversion rate of CO to CO2 and use of calcium oxide to ensure an effective CO2 absorption. The addition of Fe2O3 and CaO significantly improved the total yield of hydrogen produced in a 1-h test duration. At a temperature of 923 K, a maximum of 90% of the total hydrogen content was achieved in the produced gas.

A GIS-based assessment of coal-based hydrogen infrastructure deployment in the state of Ohio

Hydrogen infrastructure costs will vary by region as geographic characteristics and feedstocks differ. This paper proposes a method for optimizing regional hydrogen infrastructure deployment by combining detailed spatial data in a geographic information system (GIS) with a technoeconomic model of hydrogen infrastructure components. The method is applied to a case study in Ohio in which coal-based hydrogen infrastructure with carbon capture and storage (CCS) is modeled for two distribution modes at several steady-state hydrogen vehicle market penetration levels. The paper identifies the optimal infrastructure design at each market penetration as well as the costs, CO 2 emissions, and energy use associated with each infrastructure pathway. The results indicate that aggregating infrastructure at the regional-scale yields lower levelized costs of hydrogen than at the city-level at a given market penetration level, and centralized production with pipeline distribution is the favored pathway even at low market penetration. Based upon the hydrogen infrastructure designs evaluated in this paper, coal-based hydrogen production with CCS can significantly reduce transportation-related CO 2 emissions at a relatively low infrastructure cost and levelized fuel cost.

Comparison of Investment and Related Requirements for Selected Hydrogen Vehicle System Pathways

A model was developed for production, transmission, delivery, and consumption of hydrogen for large-scale systems ultimately providing shaft-work for hydrogen-based vehicles. (See Glossary, after References). Presently, the supply technologies are limited to solar photovoltaic, wind, nuclear, and nuclear thermochemical sources. Transmission technologies include electric power, hydrogen pipeline, and liquid hydrocarbon pipeline. Delivery technologies include both liquid and gaseous hydrogen and liquid hydrocarbon. Storage modes were selected as appropriate for the pathway transmission and delivery modes. Finally, consumption technologies are fuel-cell based, with and without a fuel processor (reformer). Overall, there were 39 separate pathways in this initial analysis. Subsystem efficiencies, capital costs, and capacity factors were derived from a literature search and supported by calculations where necessary. Overall systems efficiency, system peak power capital costs, and systems average power capital costs were calculated to indicate the potential capital investment requirements. The model was exercised to assess the capital cost (and related aspects) requirements to provide the equivalent automobile shaftwork of eleven million barrels of oil per day by the year 2040 (the Administration's objective). These costs range from $650 billion to $11.7 trillion and primarily depend on the selected energy source. The results reveal that nuclear thermochemical systems based on liquid hydrocarbon transmission and delivery lie at the low-cost end of the range, followed by nuclear or wind electric, then nuclear or wind hydrogen pipeline, and finally by solar electric and solar hydrogen pipeline. It is noted that thermochemical systems based on liquid hydrocarbons was the least-cost option for all of the energy sources. One vehicle storage technology, chemical hydride, was determined to be too costly to be included for later analysis. The results were compared against what might be expected of fusion energy. It was found that fusion hydrogen plant capital costs did not compete with Nuclear or Wind (but did with current Solar Photovoltaics) unless fusion plants were very large. The model is planned to be expanded to include coal-based hydrogen production (with CO2 sequestration) and extended to calculate the total cost of energy delivered to the wheels.