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.

Currently, the key challenge of the oil-refining industry worldwide is to produce environmentally friendly fuel in large volumes to meet market demand, which is due to strict environmental standards governing the permissible sulfur content in fuel. Natural gas, refinery gas, and coal gas contain acid gases such as hydrogen sulfide and carbon dioxide. These compounds must be removed from the gas stream because of the toxicity of H₂S and to prevent the acid gas-induced corrosion of pipelines and facilities. Hydrogen sulfide is released as a result of various industrial processes, and its removal is critical because this compound can cause corrosion and environmental damage even at low concentrations. Sulfur compounds are also present in natural gas, biofuels and other fuel gases used in power plants. This article proposes new adsorbents of natural and waste origin and presents the results of their testing for the removal of acid gases. This paper also considers methods for the preparation of adsorbents from waste and procedures for the removal of sulfur-containing compounds. Using agricultural, industrial waste to produce activated sorbents not only solves the problem of waste disposal but also reduces the cost of desulfurization, contributing to the creation of sustainable and environmentally friendly technologies. The Review Section comprehensively summarizes current research on hydrogen sulfide removal in gas cleaning processes using agricultural and industrial waste as highly efficient adsorbents. In the Experimental Section, 10 composite materials based on natural raw materials and wastes, as well as 6 commercial adsorbents, were synthesized and tested under laboratory conditions. The choice of materials for the adsorbent production was based on the principles of environmental friendliness, availability, and cost-effectiveness. The developed materials based on modified sludge from water treatment plants of thermal power plants are effective sorbents for the purification of gas emissions from petrochemical enterprises. For industrial use, it is necessary to solve the problems of increasing the economic attractiveness of sorbents from waste, the ability of regeneration, the competitive adsorption of pollutants, the use of indicator sorbents, the optimization of operating conditions, and safe waste disposal.

Currently, the process of creating industrial installations is associated with digital technologies and must involve the stage of developing digital models. It is also necessary to combine installations with different properties, functions, and operational principles into a single system. Some tasks require the use of predictive modeling and the creation of “digital twins”. The main processes during the fuel cell modeling involve electrochemical transformations as well as the movement of heat and mass flows, including monitoring and control processes. Numerical methods are utilized in addressing various challenges related to fuel cells, such as electrochemical modeling, collector design, performance evaluation, electrode microstructure impact, thermal stress analysis, and the innovation of structural components and materials. A digital model of the membrane-electrode unit for a solid oxide fuel cell (SOFC) is presented in the article, incorporating factors like fluid dynamics, mass transfer, and electrochemical and thermal effects within the cell structure. The mathematical model encompasses equations for momentum, mass, mode, heat and charge transfer, and electrochemical and reforming reactions. Experimental data validates the model, with a computational mesh of 55 million cells ensuring numerical stability and simulation capability. Detailed insights on chemical flow distribution, temperature, current density, and more are unveiled. Through a numerical model, the influence of various fuel types on SOFC efficiency was explored, highlighting the promising performance of petrochemical production waste as a high-efficiency, low-reagent consumption fuel with a superior fuel utilization factor. The recommended voltage range is 0.6–0.7 V, with operating temperatures of 900–1300 K to reduce temperature stresses on the cell when using synthesis gas from petrochemical waste. The molar ratio of supplied air to fuel is 6.74 when operating on synthesis gas. With these parameters, the utilization rate of methane is 0.36, carbon monoxide CO is 0.4, and hydrogen is 0.43, respectively. The molar ratio of water to synthesis gas is 2.0. These results provide an opportunity to achieve electrical efficiency of the fuel cell of 49.8% and a thermal power of 54.6 W when using synthesis gas as fuel. It was demonstrated that a high-temperature fuel cell can provide consumers with heat and electricity using fuel from waste from petrochemical production.

The article is devoted to the issues of the utilization of hydrogen-containing gas wastes in oil refining deep processing. Gas wastes consist of hydrogen, methane, ethane, propane, butane, other saturated and unsaturated C5-C7 hydrocarbons, sulfur compounds, carbon monoxide, carbon dioxide, nitrogen and oxygen. The use of a hybrid power plant for efficient conversion of the potential energy of the gas mixture into electrical and thermal energy is proposed. It is shown that gas waste from oil production has a net calorific value comparable to the calorific value of natural gas (46 and 49 MJ/kg, respectively). Fuel gas is a valuable product that can be used after desulfurization instead of burning in the atmosphere. The article proposes the developed composition of the adsorbent for hydrogen sulfide capturing, including 40% wt. bentonite, 40% wt. calcium oxide, 10% wt. zinc oxide and 10% wt. manganese oxide. The capture rate was 98.3%. A comparison of various types of fuel for a hybrid power plant with a high-temperature fuel cell and an assessment of the efficiency of using gas waste from oil refineries was carried out. It is shown that fuel gas from oil production waste has a high potential for use in power plants due to its high calorific value and a number of other advantages compared to natural gas.

In the context of limited water resources and the deterioration of natural water bodies’ state, and with the increase in the regulatory requirements for the quality of effluents, assessing the impact of the industrial and energy complex on water bodies is a task of increasingly greater significance to the whole energy sector. “zero discharge” is considered the most effective strategy for creating environmentally friendly thermal power plants. Hybrid reverse osmosis electrodialysis systems make it possible to obtain solutions with a higher concentration of components compared to single electrodialysis treatment, i.e., more efficient separation of brine and pure water. This article proposes experimental and pilot-industrial studies of a hybrid membrane system operation using industrial wastewater for the disposal of liquid waste from an ion-exchange chemical-desalting water treatment plant of a thermal power plant, followed by a calculation of economic efficiency and an analysis of the environmental feasibility of its use. The developed technological scheme offers separate processing of acidic and alkaline waste regeneration solutions using calcium carbonate reagent and desalination on baromembrane and electromembrane units to obtain clean water and dry residue. The hybrid system includes a booster filter press and an evaporator. The hybrid system makes it possible to provide a thermal power plant with a “zero discharge” with a minimum consumption of reagents and electricity, as well as return all wastewater back to the power plant cycle.

Hybrid reverse osmosis electrodialysis systems make it possible to obtain solutions with a higher concentration of components compared to single electrodialysis treatment, i.e. more efficient separation of brine and pure water. The article proposes experimental and pilot-industrial studies of a hybrid membrane system operation using industrial wastewater for the disposal of liquid waste from an ion-exchange chemical-desalting water treatment plant of a thermal power plant, followed by a calculation of economic efficiency and an analysis of the environmental feasibility of their use. The developed technological scheme offers separate processing of acidic and alkaline waste regeneration solutions using calcium carbonate reagent and desalination on baromembrane and electromembrane units to obtain clean water and dry residue. The hybrid system includes a booster filter press and an evaporator. The hybrid system makes it possible to provide a thermal power plant with a "zero discharge" with a minimum consumption of reagents and electricity, as well as return all water from wastewater to the power plant cycle.