Project Synopsis

Develop an AspenPlus simulation model and other process design information for a novel alternative electricity pilot-plant unit for a technology development company.

Project Summary

The client, an alternative energy technology development company, is designing a new process that utilizes off-peak clean energy and a novel energy storage module to generate green electricity. 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 plans on building a pilot-scale unit to prove out the technology. Process Engineering Associates, LLC (PROCESS) was contracted by the client to develop an AspenPlus model of the unit and scaled-up preliminary pilot-plant design information based on laboratory test data. Model results were tabulated in material balance tables. A Process Flow Diagram (PFD) was also developed as well as preliminary equipment sizing and a Piping and Instrument Diagram (P&ID).

The process operates batch wise with two distinct modes: energy module charging and discharging. In charge mode, the energy storage module is heated via renewable energy. During the charge mode the module is isolated from the turbo machinery and associated exchangers. As the charging material is reactive, energy addition reduces the metal oxide liberating oxygen molecules. Oxygen is removed from the energy module by the vacuum blower. As the oxygen is very hot it is cooled before being routed to the vacuum pump. The energy module is “charged” once a pre-determined temperature is reached. Once the module is charged, it is isolated from the vacuum pump.

In discharge mode, the energy storage module is made available to the turbo machinery components, the compressor, and associated heat exchangers. Ambient air is compressed and heated. The energy for preheating the air comes from partially cooled “process” air (or process “gas”) from the power storage module.

Preheated air effluent is either routed to the energy module or bypassed around the module. The amount of air bypassed is such that the inlet temperature to the steam generator downstream of the module is maintained at the target. Preheated air that enters the module is heated by an oxidation reaction and then mixed and co-mingled with the air bypass and then routed to the steam the process heater.

The process heater utilizes the high temperature waste heat available in the effluent from the energy module to generate steam at saturated conditions. The steam is then routed away from the cycle and used elsewhere. Partially cooled exhaust from the Process Heater is routed through the air preheater and then cooled with cooling water service (CWS).

Industry Type

Alternative Energy


Utilized Skills

  • Process simulation modeling
  • Process technology design support.

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