Forest residues gasification integrated with electrolysis for production of SNG – modelling and assessment
3
Citation
10
Reference
10
Related Paper
Citation Trend
Keywords:
Substitute natural gas
Methanation
Wood gas generator
Power-to-Gas
Methanation
Substitute natural gas
Power-to-Gas
Cite
Citations (1)
Polymer electrolyte membrane fuel cells (PEMFCs) are often used for household applications, utilizing hydrogen produced from natural gas from the gas grid. The hydrogen is thereby produced by steam reforming of natural gas followed by a water gas shift (WGS) unit. The H2-rich gas contains besides CO2 small amounts of CO, which deactivates the catalyst used in the PEMFCs. Preferential oxidation has so far been a reliable process to reduce this concentration but valuable H2 is also partly converted. Selective CO methanation considered as an attractive alternative. However, CO2 methanation consuming the valuable H2 has to be minimized. The modelling of selective CO methanation in a household fuel cell system is presented. The simulation was conducted for single and two-stage adiabatic fixed bed reactors (in the latter case with intermediate cooling), and the best operating conditions to achieve the required residual CO content (100 ppm) were calculated. This was done by varying the gas inlet temperature as well as the mass of the catalyst. The feed gas represented a reformate gas downstream of a typical WGS reaction unit (0.5%–1% CO, 10%–25% CO2, and 5%–20% H2O (rest H2)).
Methanation
Water-gas shift reaction
Power-to-Gas
Substitute natural gas
Catalytic reforming
Renewable natural gas
PROX
Cite
Citations (7)
Synthetic natural gas (SNG) production from coal is considered again due to rising prices for natural gas, the wish for less dependency from natural gas imports and the opportunity of reducing green house gases. The technical, economic and ecological feasibility of SNG with Mo-based catalysts showed water-gas shift and sulfur-resistant methanation has been studied. In this paper the impact of B2O3 loading on the MoO3/CeO2-Al2O3 catalysts for sulfur-resistant methanation was investigated. The catalysts were prepared by impregnation method and characterized by means of BET, XRD, TEM and NH3-TPD. The results showed that the sulfur-resistant methanation activity of MoO3/CeO2-Al2O3 catalysts were increased at first and then decreased as the increase of B2O3 loading. The catalyst adding 0.5% B2O3 showed the highest activity and the conversion of CO was 55%. The characterization results indicated that the addition of B2O3 had influences on the structure and surface acidity of catalysts and the dispersion of active components, which further impacted the activity of catalysts. Highcrystallization and enhancement of strong acid quantity were not beneficial to the sulfur-resistant methanation, while the high dispersion of active components was favorable to the improvement of the catalyst activity.
Methanation
Substitute natural gas
Water-gas shift reaction
Cite
Citations (0)
CO2 methanation is a well-known reaction that is of interest as a capture and storage (CCS) process and as a renewable energy storage system based on a power-to-gas conversion process by substitute or synthetic natural gas (SNG) production. Integrating water electrolysis and CO2 methanation is a highly effective way to store energy produced by renewables sources. The conversion of electricity into methane takes place via two steps: hydrogen is produced by electrolysis and converted to methane by CO2 methanation. The effectiveness and efficiency of power-to-gas plants strongly depend on the CO2 methanation process. For this reason, research on CO2 methanation has intensified over the last 10 years. The rise of active, selective, and stable catalysts is the core of the CO2 methanation process. Novel, heterogeneous catalysts have been tested and tuned such that the CO2 methanation process increases their productivity. The present work aims to give a critical overview of CO2 methanation catalyst production and research carried out in the last 50 years. The fundamentals of reaction mechanism, catalyst deactivation, and catalyst promoters, as well as a discussion of current and future developments in CO2 methanation, are also included.
Methanation
Substitute natural gas
Power-to-Gas
Cite
Citations (576)
Three different power-to-methane process chains with grid injection in two scales (1 MW el and 6 MW el ) were analysed regarding their investment and operation cost. The process chains were based on biological or catalytic bubbling fluidised bed methanation in combination with proton exchange membrane or solid oxide electrolyser cells. A bottom-up techno-economic analysis showed a cost benefit of around 17–19% lower biomethane production cost for the bubbling fluidised bed technology as less than a third of the reactor volumes is required for catalytic methanation. This cost benefit is only given in combination with PEM electrolysis, as the high-temperature electrolyser stacks currently result in high investment cost. Based on electricity cost of 5 €-ct/kWh el and a plant size of 6 MW el , biomethane production cost of 13.95 €-ct./kWh for catalytic and 17.30 €-ct/kWh for biological methanation could be obtained, both including PEM electrolysis. A significant efficiency increase by integrating the heat of catalytic methanation reaction with the high-temperature electrolysis can be achieved; however investment cost have to decrease below 1000 €/kW el to obtain economically feasible production cost of biomethane. Under current economic and technological circumstances, CO 2 methanation using the bubbling fluidised bed technology is the most cost effective.
Methanation
Power-to-Gas
Substitute natural gas
High Temperature Electrolysis
Cite
Citations (12)
A series of α-Al2O3-supported Ni catalysts with different Ni particle sizes (5–10, 10–20, and 20–35 nm) were prepared and applied in the CO methanation reaction for the production of synthetic natural gas (SNG). The catalytic tests showed that the Ni nanoparticles influenced the catalytic performance in the CO methanation, and the catalyst with a Ni nanoparticle size of 10–20 nm showed the highest CO conversion, CH4 yield, and turnover frequency, and the lowest carbon deposition, demonstrating the possibility of improving the Ni/α-Al2O3 catalysts in the CO methanation for SNG production by controlling their Ni particle size.
Methanation
Substitute natural gas
Carbon fibers
Cite
Citations (114)
Methanation, or the generation of synthetic methane through the combination of carbon dioxide and hydrogen, has been attracting more and more attention of researchers and energy scientists in recent years due to the fact that the development of an effective and economically feasible technology for the implementation of this process will allow solving a number of energy and environmental problems. First, it is the accumulation of excess renewable electricity from solar and wind power plants by using it in the creation of another energy-intensive product, namely synthetic natural gas, which removes the problem of coordinating unstable sources of electricity with energy networks. Secondly, methanation becomes another technology for enriching biogas and turning it into biomethane, which will allow it to be used through existing gas networks and contribute to solving the problem of natural gas shortage.
The development and improvement of methanation technologies are engaged in many organizations of the world - Germany, Denmark, France, the USA, Japan and others. Research is conducted in two main directions: catalytic methanation and biological methanation. In the first direction, methanation is carried out through the Sabatier reaction using catalysts. The problems of such methanation are: the development of catalysts with high activity, selectivity and resistance to the heat of reaction, the provision of optimal reaction modes, in particular temperature and pressure, through the use of various methods of reactor cooling, control of the reaction mechanism, the use of three-phase reactors, changing their structure, and so on. Biological methanation is carried out using of biological methanogens - so-called archaea, which act as a kind of catalyst. The methanation is carried out either directly in the biomass anaerobic digestion reactor (in-situ methanation) or in a separate reactor into which biogas and hydrogen are fed separately (ex-situ methanation). One of the main problems of in-situ methanation is the simultaneous provision of optimal conditions for both acetoclastic and hydrogenotrophic methanogens. This problem is solved by ex-situ methanation, in which the optimal conditions for anaerobic digestion and methanation processes are provided separately. It is clear that optimal conditions are also provided for biomethanation of pure CO2 and H2, when the «broth» for archaea is created separately. A comparison of catalytic and biological methanation technologies shows that catalytic methanation provides higher energy efficiency and requires much smaller reactor sizes than biological methanation for the same methane yield. However, the latter has a higher resistance to harmful impurities than the catalytic one.
Methanation
Substitute natural gas
Power-to-Gas
Biogas
Cite
Citations (2)
Biochar derived from the fast pyrolysis of lauan was activated to develop its pore structure and used as a catalyst support in the methanation of bio-syngas. The physicochemical properties of the support and the ruthenium (Ru)/activated biochar (ABC) catalysts used were characterized using multiple characterization techniques. The effect of Ru loading on bio-syngas methanation was investigated using a range of ABC supported Ru catalysts. CO conversion was low during bio-syngas methanation due to the low H2 content and was increased upon increasing the Ru loading. However, increasing the H2/(CO + CO2) ratio in bio-syngas by addition of H2 significantly improved the conversion of CO and CO2. The CO2 conversion was increased to 17.5% and 55%. CO conversion was 74% and 97% and the selectivity of CH4 reached 84% and 92% using a H2/(CO + CO2) ratio of 2 and 4, respectively.
Methanation
Cite
Citations (57)
Methanation
Substitute natural gas
Non-blocking I/O
Space velocity
Cite
Citations (23)
Methanation
Substitute natural gas
Reaction rate
Water-gas shift reaction
Fraction (chemistry)
Cite
Citations (31)