Develop a process simulation model for a batch thermo-chemical energy storage steam generation demonstration unit.
The client, a technology development company, is designing a new process configuration that utilizes off-peak clean energy and a novel energy storage module to generate green electricity. A major utility company has requested the client to provide a preliminary design and cost estimate of a commercial size power system. The client’s Thermal Energy Storage module is coupled with a fire-tube boiler unit to produce a desired quantity of high-pressure superheated steam. The unit would be used to replace an oil-fired steam boiler unit. Process Engineering Associates, LLC (PROCESS) was contracted by the client to develop a simulation model of the power process.
The energy storage module exploits the energy potential of metals under oxidizing and reducing conditions. Thermal energy liberated during the oxidation step is used to heat air that can power turbo machinery or generate steam. The client has demonstrated bench scale units and is currently demonstrating a pilot scale unit.
While the process can be operated in a quasi-steady condition, it is more typical that the system be operated batch wise. In batch operation there are two distinct modes: energy module charging, reducing conditions, and discharging, operating under oxidizing conditions. In charge mode, the energy storage module is heated via renewable energy. During the charge mode, the module is isolated from the other equipment. The working media component of the energy module is a metal oxide. As this material is reactive, energy addition reduces the metal oxide liberating oxygen molecules. Oxygen is then removed from the energy module system. The energy module is “charged” once a certain temperature is reached.
In discharge mode, the energy storage module is made available to the other component of the process configuration. In this case that would be a fire tube boiler. Ambient air is compressed via a rotary blower and then routed to the thermal module. Oxygen in the air stream slowly “discharges” the media thereby recovering thermal energy. The air stream is heated to very high temperatures in the thermal energy storage module. High temperature air from the modules is then routed through the fire tube boiler where it is cooled via the generation of medium-pressure steam. The steam is then routed to the customer for their use.
Simulation model results were tabulated in Material Balance tables. A Process Flow Diagram (PFD) was developed. A table of preliminary equipment sizes and a Piping and Instrument Diagram (P&ID) were generated. The output from these items provided the input to a ROM Total Installed Cost estimate for the installation. PROCESS completed this work, and the utility company is considering moving forward with the next step of engineering design.
Alternative Electrical Energy Production
- Process simulation development
- Preliminary process design
- Process cost estimation.