Power plant with energy recovery from fuel storage

Abstract

Power plant systems and processes are described that enable recovery of at least a portion of the fuel storage energy associated with a storage system for supplying fuel to the power plant systems. A first embodiment of an energy-recovery power plant system includes at least one fuel storage container and at least one expander that can receive fuel from the fuel storage container at a first pressure and provide the fuel to the power plant at a second pressure that is lower than the first pressure. A second embodiment of an energy-recovery power plant system includes a first conduit fluidly coupling the fuel storage container and the power plant for delivering fuel from the fuel storage container to the power plant and at least one regenerative thermodynamic cycle engine thermally coupled to the first conduit such that heat may be exchanged between the fuel and a working fluid for the regenerative thermodynamic cycle engine.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001] The present application claims priority from prior pending U.S. provisional application No. 60 / 260,608, filed on Jan. 9, 2001, which is incorporated herein by reference.FIELD[0002] The present disclosure relates to a power plant system that includes a fuel storage system.BACKGROUND[0003] Fuel cells provide an environmentally friendly source of electrical power. One form of fuel cell used for generating electrical power, particularly for vehicle propulsion and for smaller scale stationary power generation, includes an anode channel for receiving a flow of hydrogen gas, a cathode channel for receiving a flow of oxygen gas, and a polymer electrolyte membrane (PEM) which separates the anode channel from the cathode channel. Oxygen gas entering the cathode reacts with hydrogen ions that cross the electrolyte to generate a flow of electrons. Environmentally safe water vapor is also produced as a byproduct.[0004] Despite the great attractiveness...

AI Technical Summary

Benefits of technology

0012] In such power plant systems, mechanical power and/or thermal energy may be recovered from the fuel storage systems. For example, a process is disclosed herein that involves providing

Problems solved by technology

Despite the great attractiveness of fueling future mobile and stationary power plants with hydrogen, severe technical and economic barriers are presented by the supply and storage of hydrogen (as either a compressed gas or a cryogenic liquid).

In the absence of any system for recovering energy as hydrogen fuel is released from storage, this energy loss seriously impairs the overall efficiency and economic viability of the so-called "hydrogen economy", as popularly represented by distributed fuel cell energy systems using hydrogen generated by renewable energy sources such as solar photovoltaic power.

In particular, the economic viability of hydrogen and natural gas as fuels particularly for vehicular propulsion has been gravely compromised by the loss of energy required to compress or liquefy these fuels in the fuel supply infrastructure.

There has been a lack of practical devices and methods for recovering hydrogen storage energy to enhance the performance and efficiency of the fuel cell power plant, particularly for small-scale fuel cell power plants.

This system is often cumbersome and expensive to implement due to the large size of the adsorbers and the complexity of the valving required.

Further, the conventional PSA system makes inefficient use of applied energy because of irreversible gas expansion steps as adsorbers are cyclically pressurized and depressurized within the PSA process.

Conventional PSA systems could not be applied to fuel cell power plants for vehicles, as such PSA systems are far too bulky and heavy because of their low cycle frequency and consequently large adsorbent inventory.

A serious challenge for oxygen enrichment by PSA or VPSA using nitrogen-selective zeolite adsorbents arises from the strongly hydrophilic nature of those adsorbents.

In intermittent operation, adsorbed water in the desiccant layer may diffuse into the nitrogen-selective adsorbent zone and cause deactivation of that adsorbent during shutdown intervals.

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