Residential Solid Oxide Fuel Cell Generator Fuelled by Ethanol: Cell, Stack and System Modelling with a Preliminary Experiment

Abstract

The flexibility and feasibility of a 5 kW SOFC generator designed for natural gas (NG) and fuelled by a non‐conventional liquid fuel such as ethanol is analysed. A complete generator model is implemented to predict and determine the main criticalities when ethanol fuel is adoperated. The main balance‐of‐plant (BoP) units considered are the reformer, the recirculation system based on an ejector, the tubular cells bundles constituting the stack unit, the after‐burner zone and the air blower. The electrical and global efficiencies achieved at nominal operating conditions show how ethanol maintains generator performance good, while only slightly reducing the system AC efficiency from 48% (achieved by NG) to 45%. The effectiveness and flexibility of the recirculation system when changing the fuel is also verified since a safe steam‐to‐carbon ratio (STCR) is established after the fuel is switched from NG ethanol. The stack thermal management is analysed in detail and related to the system performances, showing how a high endothermic fuel reforming reaction is required to maintain the overall system efficiency. A preliminary experiment with ethanol feeding the Siemens generator is finally presented. The system response to the new fuel is monitored by several measured parameters and the system regulation is explained.

5kWe+5kWt reformer-PEMFC energy generator from bioethanol first data on the fuel processor from a demonstrative project

“…Finally, a few hours operation of a 5 kW SOFC system with ethanol as fuel instead of natural gas has been described by Lanzini et al [30], together with a thorough simulation of the native NG-fuelled plant. A balance of plant of a similar system has been also simulated [16].…”

Gas Recirculation at the Hydrogen Electrode of Solid Oxide Fuel Cell and Solid Oxide Electrolysis Cell Systems

“…Widely considered for SOFC systems is the use of ejectors which are being investigated theoretically and experimentally (e.g., [1][2][3][4][5][6][7]). In some applications (especially SOEC systems and combined systems of gas turbine and SOFC) increased operating pressure can also be a requirement.…”

“…In some applications (especially SOEC systems and combined systems of gas turbine and SOFC) increased operating pressure can also be a requirement. Widely considered for SOFC systems is the use of ejectors which are being investigated theoretically and experimentally (e.g., [1][2][3][4][5][6][7]). Ejectors can be manufactured from high temperature steels and are well suited for the application due to the lack of moving parts.…”

Recent key technical barriers in solid oxide fuel cell technology

“…Without moving parts, we would expect enhanced reliability and lower maintenance cost. Secondly, SOFCs (by virtue of high temperature operation) can extract hydrogen from a variety of fuels [16,17]. SOFC is the most sulfur-resistant (as H 2 S and COS) fuel cell.…”