1,721,190 research outputs found
Experimental investigation of direct internal reforming of biogas in solid oxide fuel cells
No full textHydrogen blending into the gas distribution grid: the case study of a small municipality
No full textHydrogen blending into the gas network may offer an alternative concept for the storage of
the exceeding energy from renewable power sources, improving the flexibility of the
energy system through the integration of the electricity and gas networks. This scenario
foresees the use of electrolyzers to convert power into hydrogen gas. The gas grid could
both provide storage and act as the transport facility of the produced gas, taking
advantage of the robustness and extensiveness of an already existing energy
infrastructure.
In this work, a steady state and multi-species thermal-fluid-dynamic model of the gas
network is applied to a portion of the Italian distribution network, located in EmiliaRomagna,
covering a surface of 2,900 ha and having a throughput of 8.25 MSm3
/year of
natural gas.
The receiving potential capacity of the existing infrastructure is assessed with respect to
hydrogen injection. Fluid-dynamic effects of the hydrogen blending are considered and
commented.
The maximum allowable percentage of injectable hydrogen is calculated on a nodal basis,
referring to the actual gas network configuration. The current Italian regulation on
distributed injection (DM 19/02/2007) of gases into the natural gas network only allows
injecting gases having nearly the same quality of natural gas (UNI-EN 437), thus excluding
any blending practice. However, in the simulated scenario here proposed, it is assumed
that gas quality requirements are on the network as a whole (i.e., after blending of
hydrogen in the grid) rather than at the single injection point. By exploiting the qualitytracking
feature of the model, the constraint of quality assessment at the injection point is
thus relaxed.
Once the blending limit is known for each node, the amount of injectable hydrogen is
calculated accordingly, taking into account the amount of natural gas already flowing
through the node itself.
The node with the major injection capability is the designated one for the injection and
used for the simulation of the case study.
Finally, a comparison between the ‘base case’ and the ‘maximum hydrogen injection case’
is presented and discussed showing how hydrogen blending into the gas grid may lead to
a reduction on the fossil natural gas supply of up to 2,1%
Microstructural characterization of solid oxide fuel cell electrodes by image analysis technique
Full text linkTechno-economic and policy requirements for the market-entry of the fuel cell micro-CHP system in the residential sector
No full textThis work analyses the impact of different support schemes on the retail price of micro-combined heat
and power units based on solid oxide fuel cells in the residential sector. The implications of each
incentive toward the technical implementation of the technology are also analyzed.
A detailed techno-economic assessment of the micro-combined heat and power unit is provided con-
sidering the best-in-class ceramic fuel cell technology and today’s costs for gas and electricity in the res-
idential sector. The Italian case study was used to evaluate the impact of different supporting schemes. In
order to further extend the validity of our research, scenarios for Germany and Denmark are simulated
and discussed.
For large-family residential users consuming 9000 kWh of electricity yearly, the retail price that yields
a five year pay-back-time – without any incentive – is
2500
€
. Under the same assumptions, for the
average family with a consumption of around 3500 kWh, the required price is
650
€
. In both cases, a
retail price that is four and seven time higher respectively is achieved with the
Feed-in Tariff
(
FIT
) scheme
of the type currently in use in the United Kingdom. A modified
Feed-in Tariff
is finally proposed to support
on-site consumption rather than generation with export to the gri
Low Temperature Fischer-Tropsch fuels from syngas: Kinetic modeling and process simulation of different plant configurations
No full textFischer–Tropsch synthesis is considered a key component of alternative-to-oil technology pathways to
obtain synthetic liquid hydrocarbons usable for fuels and chemicals. In view of the growing interest
and establishment of more and more syngas-to-liquids projects, it is essential to develop new process
models that are at the same time detailed and practical-to-use. Aiming at this target, up-to-date literature
kinetics research results have been converted into a well-established industrial process simulator. Low
Temperature Fischer-Tropsch process oriented to middle distillate production is modeled in detail in this
work. Detailed kinetic based on Langmuir–Hinshelwood–Hougen–Watson approach are exploited rather
than traditional product distribution laws, both for Fischer Tropsch synthesis as well as hydrocracking. By
varying the operating conditions and system process configurations, it is possible to simulate and analyse
the performance of once-through and recycle plants with different product outputs
Greening the gas network - The need for modelling the distributed injection of alternative fuels
No full textThe recent unfolding of natural gas sources, especially unconventional gas shales and substituted natural gas from renewables, can boost the transition toward a low carbon energy system. However, it is necessary to study how the gas network, traditionally supplied with fossil fuel gas, could be operated in a more complex scenario that includes multiple and distributed energy sources.
This work deals with the development of a mathematical model able to simulate transmission pipeline networks under steady-state condition while adopting a non-isothermal approach. A review of modelling approaches of fluid flow in gas pipelines and gas pipeline networks is provided. An algebraic formulation to describe compressible fluid networks is also described in detail and implemented for the first time in this work with the aim to simulate the distributed injection of green fuel gasses into the natural gas network. Hydrogen blending (e.g., from power-to-gas systems) and substituted natural gas (e.g., from biogas upgrading or power-to-gas systems) injection are considered.
A numerical simulation of a regional-scale natural gas transmission system is performed where green gasses are injected into the grid. In the case of hydrogen blending, the maximum quantity of injectable hydrogen in each node is calculated to achieve a 10% blend as an upper constraint. In conclusion, the impact of green fuels injection in the gas network on the resulting natural gas quality (i.e., Wobbe index, gas gravity, higher heating value) is investigated thoroughly
Simulation and validation of a Power-to-Power system with hydrogen storage in microporous adsorbent materials
No full text
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