.TransiEnt.Producer.Gas.MethanatorSystem.FeedInStation_Methanation

Information

1. Purpose of model

This model represents a feed in station where hydrogen is produced with an electrolyzer and methanated in a methanator to be fed in into a natural gas grid.

2. Level of detail, physical effects considered, and physical insight

The hydrogen can be produced in an electrolyzer and be stored if desired. Herefore one of the FeedInSystems with an electrolzer can be chosen.

The methanation of hydrogen takes place after the hydrogen production and the possible storage.

The methanation can be avoided by a bypass. This bypass is is controlled by the output molar content of hydrogen which can be defined by the parameter 'hydrogenContentOutput'. If this parameter is set to '1' all hydrogen is bypassed. If the parameter is set to '0' all hydrogen is methanated. The bypass fraction is controlled via a PID-controller whereby the set value is equal to 'hydrogenContentOutput'. if 'useVariableHydrogenFraction'=false the meassurement-signal is equal to the volumetric hydrogen fraction at the output. If 'useVariableHydrogenFraction'=true the meassurement-signal is equal to the input value 'hydrogenFraction_input'. This allows defining the hydrogen fraction in the SNG depending of the hydrogen fraction in an outer gas grid.

Consider that the output of the methanator still contains hydrogen such that an actual molar hydrogen content of '0' can not be achieved.

Via the parameter 'useSeperateHydrogenOutput' an additional hydrogen output can be activated. The gas of this output is not methanated before and can be controlled via the input m_flow_feedIn_H2.

Via parameter 'useLeakageMassFlow' a small mass flow of 'simCenter.m_flow_small' is always flowing out of gas ports (to avoid Zero-Mass-Flow problems)

3. Limits of validity

see sub models

4. Interfaces

P_el_set: input for the set value for the electric power

m_flow_feedIn: input for the possible feed-in mass flow into the natural grid etc.

m_flow_feedIn_H2: input for the possible feed-in mass flow of Hydrogen into the natural grid etc.

epp: electric power port for the electrolyzer

gasPortOut: outlet of SNG

gasPortOut_H2: outlet of hydrogen

5. Nomenclature

(no elements)

6. Governing Equations

(no remarks)

7. Remarks for Usage

For start up, a small hydrogen mass flow for the electrolyzer can be set to allow for simpler initialisation.

If useMassFlowControl=true, the electrical power of the electrolyzer will no more be limited by given m_flow_feed. This simplifies the controller if limitation is not needed. useMassFlowControl=false should only be used if feedInStation_Hydrogen has no hydrogen storage and the parameter useMassFlowControl is set to 'false' in feedInStation_Hydrogen as well.

8. Validation

Tested in check model TransiEnt.Producer.Gas.MethanatorSystem.Check.Test FeedInStation_Methanator

9. References

(no remarks)

10. Version History

Model created by Oliver Schülting (oliver.schuelting@tuhh.de) in Feb 2018

Model modified by Oliver Schülting (oliver.schuelting@tuhh.de) in Jul 2018: added conditional separate hydrogen port

Model modified by Oliver Schülting (oliver.schuelting@tuhh.de) in Nov 2018: TWV for Hydrogen output is controled without PID now for faster simulation results. useLeakageMassFlow added

Model modified by Oliver Schülting (oliver.schuelting@tuhh.de) in April 2019: added Boolean useMassFlowControl

Model modified by Carsten Bode (c.bode@tuhh.de), Feb 2021 (added separate medium models for CO2 and H2/SNG)