Abstract
An innovative hybrid plant, composed by a solar section for heating up a molten salt stream through a Concentrating Solar Power (CSP) plant, a chemical section for the production of 1000 Nm3/h of Enriched Methane (EM) with a 20 %vol. content of hydrogen, and an electrical section for the electricity production by means of an Organic Rankine Cycle unit (conversion efficiency = 28 %) is presented and assessed. The core of the process is the low-temperature solar steam reformer, where a feedstock composed by methane and water steam is partially converted to hydrogen. The reactor is modeled in detail, the equations set is described and commented, together with the boundary conditions. Then, the reactors’ behavior is simulated. By applying 15 reformers in parallel and imposing a Gas Hourly Space Velocity (GHSV) of 40,965 h−1, it is possible to produce a stream of EM (20 %vol. H2) equal to 1000 Nm3/h and 500 kW approximately of net electrical power output. The molten salt stream is heated up to 550 °C by the CSP plant, then it supplies the reforming process heat duty (reactor heat duty, feedstock preheating, and reactant steam generation) and, finally, it generates the electricity by exploiting its residual sensible heat. By the simulation of the reformers under industrial conditions, the feasibility of the proposed architecture is demonstrated and its potentialities are assessed.
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Abbreviations
- C i :
-
i-component composition (mol m−3)
- c p :
-
Gas mixture specific heat (J kg−1 K−1)
- c p,MS :
-
Molten salt specific heat (J kg−1 K−1)
- CSP:
-
Concentrating Solar Plant
- D er :
-
Effective radial diffusivity (m2 s−1)
- d p :
-
Equivalent catalyst particle diameter (m)
- EM:
-
Enriched Methane
- f :
-
Friction factor
- G :
-
Superficial mass flow velocity (kg s−1 m−2)
- GHSV:
-
Gas Hourly Space Velocity (h−1)
- MDEA:
-
Methyl diethanolamine
- n reformers :
-
Number of reformers inside the shell
- ORC:
-
Organic Rankine Cycle
- P :
-
Reaction pressure (Pa)
- PDE:
-
Partial Differential Equation
- PSA:
-
Pressure Swing Adsorption
- r :
-
Radial coordinate (m)
- r i :
-
Total reaction rate of the i-component (mol kg −1cat s−1)
- r j :
-
Reaction rate of reaction j (mol kg −1cat s−1)
- r t :
-
Catalytic tube radius (m)
- T :
-
Gas mixture temperature (K)
- T MS :
-
Molten salt temperature (K)
- U :
-
Global heat exchange coefficient between the molten salt and reaction packed bed (J m−2 s−1 K−1)
- u s :
-
Gas velocity (m s−1)
- w MS :
-
Molten salt mass flow rate (kg/s)
- z :
-
Axial coordinate (m)
- ∆H j :
-
Enthalpy of reaction j (J mol−1)
- ɛ :
-
Void fraction of the catalytic bed
- λ er :
-
Effective thermal conductivity (J m−1 h−1 K−1)
- µ g :
-
Gas mixture viscosity (kg m−1 K−1)
- ρ B :
-
Catalytic bed density (kg m−3)
- ρ g :
-
Gas density (kg m−3)
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De Falco, M. (2016). Enriched Methane Production Through a Low Temperature Steam Reforming Reactor. In: De Falco, M., Basile, A. (eds) Enriched Methane. Green Energy and Technology. Springer, Cham. https://doi.org/10.1007/978-3-319-22192-2_2
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DOI: https://doi.org/10.1007/978-3-319-22192-2_2
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