Theoretical and Experimental Studies of Combined Heat and Power Systems with SOFCs

Abstract

The article presents an overview of experimental layout design solutions and the general operation scheme of combined heat and power systems with a high-temperature solid oxide fuel cell (SOFC). This system is an environmentally friendly and energy-saving way to produce electricity and heat. The use of high-temperature SOFCs makes it possible to obtain an electrical efficiency of 45–55%. Combining the electrochemical and mechanical system can increase the total efficiency by up to 60–65% in a hybrid power plant. This article discusses the structure and relationship between the components of a hybrid power plant and various modification options for efficient power generation. The technological schemes for existing and tested hybrid power plants with an SOFC and gas turbine are presented and described in detail. When designing a hybrid power plant, the key factors are the choice of design, heat source, and fuel-reforming method; the design of a solid oxide fuel cell and the number of modules in a stack; selecting devices for generating electricity with the development of cogeneration or trigeneration cycles (for possible use in thermal power plants and for the energy supply of social facilities); the direction of material flows within the system; pressure and tightness; and the interconnection of the hybrid power system elements. Researchers have accumulated and described in scientific papers extensive experience in designing, theoretical research, and numerical modeling of hybrid power plants with high-temperature SOFCs. It is shown that experimental hybrid power plants based on SOFCs of the megawatt class are in operation. Hybrid systems with an SOFC are designed only for the kilowatt power class. Trigeneration systems with a steam turbine exist only in the form of theoretical calculations. Trigeneration systems show the highest electrical efficiency, but the highest construction and service costs. Systems based on high-temperature SOFCs can be used for autonomous systems, and in combination with gas and steam turbines only at thermal power plants. Experimental laboratory studies are limited by the high cost of installations and the difficulties of testing the possibility of using combined heat and power systems on an industrial scale. Therefore, a more detailed study of the relationship between the units of a combined heat and power system is recommended in order to achieve the high efficiency indicators obtained from theoretical studies.

A Review on Solid Oxide Fuel Cell Technology: An Efficient Energy Conversion System

“…Another practical option is the proton-conducting ceramic fuel cell (PCFC), which is a SOFC that operates at low to intermediate temperatures [119]. Difficulties arise during coupling SOFC fuel stack with gas turbine in the complex system configuration [120]. Continuous operation can also lead to sudden disruption of electricity generation.…”

“…Carbon released can be controlled through carbon capture technologies [121,122]. Majority of the expenditures associated with a SOFC system are related to the cost of the infrastructure, fuel, and equipment [120], thereby limiting its economic viability as power source.…”

Numerical Simulation of Processes in an Electrochemical Cell Using COMSOL Multiphysics

“…In an electrochemical cell, certain factors can lead to irreversible voltage losses [33], including:…”

Sintering Aid Strategy for Promoting Oxygen Reduction Reaction on High-Performance Double-Layer LaNi0.6Fe0.4O3–δ Composite Electrode for Devices Based on Solid-State Membranes

“…Simple solid oxides have attracted much attention due to their diverse physical and chemical properties [ 1 , 2 , 3 ]. Complex oxides have found numerous applications in high-temperature electrochemical devices for power-to-gas or gas-to-power systems [ 4 , 5 , 6 , 7 ]. If the complex oxide has high ionic conductivity, it can be used as an ion-conducting membrane in high-temperature devices [ 8 , 9 ].…”