scholarly journals Methane Pyrolysis in Molten Potassium Chloride: An Experimental and Economic Analysis

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8182
Author(s):  
Jinho Boo ◽  
Eun Hee Ko ◽  
No-Kuk Park ◽  
Changkook Ryu ◽  
Yo-Han Kim ◽  
...  

Although steam methane reforming (CH4 + 2H2O → 4H2 + CO2) is the most commercialized process for producing hydrogen from methane, more than 10 kg of carbon dioxide is emitted to produce 1 kg of hydrogen. Methane pyrolysis (CH4 → 2H2 + C) has attracted much attention as an alternative to steam methane reforming because the co-product of hydrogen is solid carbon. In this study, the simultaneous production of hydrogen and separable solid carbon from methane was experimentally achieved in a bubble column filled with molten potassium chloride. The melt acted as a carbon-separating agent and as a pyrolytic catalyst, and enabled 40 h of continuous running without catalytic deactivation with an apparent activation energy of 277 kJ/mole. The resultant solid was purified by water washing or acid washing, or heating at high temperature to remove salt residues from the carbon. Heating the solid product at 1200 °C produced the highest purity carbon (97.2 at%). The economic feasibility of methane pyrolysis was evaluated by varying key parameters, that is, melt loss, melt price, and carbon revenue. Given a potassium chloride loss of <0.1 kg of salt per kg of produced carbon, the carbon revenue was calculated to be USD > 0.45 per kg of produced carbon. In this case, methane pyrolysis using molten potassium chloride may be comparable to steam methane reforming with carbon capture storage.

2021 ◽  
Vol 11 (13) ◽  
pp. 6021
Author(s):  
Shinje Lee ◽  
Hyun Seung Kim ◽  
Junhyung Park ◽  
Boo Min Kang ◽  
Churl-Hee Cho ◽  
...  

Steam methane reforming (SMR) process is regarded as a viable option to satisfy the growing demand for hydrogen, mainly because of its capability for the mass production of hydrogen and the maturity of the technology. In this study, an economically optimal process configuration of SMR is proposed by investigating six scenarios with different design and operating conditions, including CO2 emission permits and CO2 capture and sale. Of the six scenarios, the process configuration involving CO2 capture and sale is the most economical, with an H2 production cost of $1.80/kg-H2. A wide range of economic analyses is performed to identify the tradeoffs and cost drivers of the SMR process in the economically optimal scenario. Depending on the CO2 selling price and the CO2 capture cost, the economic feasibility of the SMR-based H2 production process can be further improved.


Author(s):  
Deborah A. Udousoro ◽  
Cliff Dansoh

One of the challenges faced in the United Kingdom energy market is the need to supply clean energy at affordable prices. Hydrogen can be used as an energy carrier and has been applied as fuel for automotive engines. Several technologies exist for the production of hydrogen fuel but their acceptance is dependent on the cost and impact on the environment. Steam methane reforming is an established hydrogen production process in the UK. Currently there are 8 fuel cell buses that run on hydrogen fuel but the hydrogen used is produced via steam methane reforming. Production of hydrogen through solar powered electrolysis is a cleaner option but at what economic cost? In this paper, cost analysis is conducted to compare the cost of producing the amount of hydrogen needed to run the RV1 fuel cell buses at Lea Interchange bus garage through steam methane reforming of natural gas to solar powered water electrolysis. From the analysis it was discovered that levelised energy cost of solar powered electrolysis system is 15 times the levelised energy cost of steam methane reforming of natural gas. Thus, the production of hydrogen is not economically feasible through solar powered water electrolysis system.


Author(s):  
G. Tsatsaronis ◽  
A. Boyano ◽  
T. Morosuk ◽  
A. M. Blanco-Marigorta

In this paper, an advanced exergoenvironmental analysis is conducted for a steam methane reforming process for the production of hydrogen. The approach for calculating pollutant formation is generalized and the assumptions required for applying the analysis are discussed in detail. These are the main contributions of this work to the development of exergy-based methods for the analysis of energy-intensive chemical processes. In an advanced exergoenvironmental analysis, the environmental impact associated with the exergy destruction within a component as well as the component-related environmental impact and a component-related pollutant formation are split into unavoidable/avoidable and endogenous/exogenous parts. This splitting improves our understanding of the sources of thermodynamic inefficiencies and their effect to the formation of environmental impacts and pollutants, and facilitates a subsequent improvement of the overall process. Finally, some improvement options developed on the basis of the results of the advanced exergoenvironmental analysis are discussed.


Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1348
Author(s):  
Philipp Kenkel ◽  
Timo Wassermann ◽  
Edwin Zondervan

Biogas is a significant by-product produced in algae processing and may be used for many different applications, not only as a renewable energy carrier but also as a chemical intermediate in integrated algae-based biorefineries. In this work, the reforming of biogas to H2/CO2 mixtures (referred to as SynFeed) as feed for the direct hydrogenation of CO2 to methanol is investigated. Two conventional processes, namely steam methane and autothermal reforming, with upstream CO2 separation from raw biogas are compared to novel concepts of direct biogas bi- and tri-reforming. In addition, downstream CO2 separation from SynFeed using the commercial Selexol process to produce pure H2 and CO2 is considered. The results show that upstream CO2 separation with subsequent steam methane reforming is the most economic process, costing 142.48 €/tSynFeed, and taking into consideration the revenue from excess hydrogen. Bi-reforming is the most expensive process, with a cost of 413.44 €/tSynFeed, due to the high demand of raw biogas input. Overall, SynFeed from biogas is more economical than SynFeed from CO2 capture and water electrolysis (464 €/tSynFeed), but is slightly more expensive than using natural gas as an input (107 €/SynFeed). Carbon capture using Selexol comes with costs of 22.58–27.19 €/tCO2, where approximately 50% of the costs are derived from the final CO2 compression.


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