Issue 04/2024 (April)

This review paper presents a technical and historical overview of the Polish gas industry in the context of upcoming changes related to the use of hydrogen. The history of the transport of various gaseous fuels is presented: coal and coke-oven gas (with a high content of approx. 50% hydrogen), natural gas and the current problem of the use of biomethane and hydrogen, (pure and blended with natural gas). Technical issues related to the safe operation of gas networks for different types of fuel and for fuel conversion scenarios are also presented. The experience of the gas sector in working with flammable media, forming explosive atmospheres and transported under pressure in extensive infrastructures is sufficient to meet the tasks of the current energy transition, with a prospective mixed hydrogen-biomethane system or a separated methane and hydrogen system.

The article discusses pumping stations and the technological solutions used in them as elements of the gas transmission system. A method for modelling flow machines that can be used for simulation and optimisation calculations of the transmission system is presented. The method includes a model of a centrifugal compressor enabling the efficiency of the compression process to be determined under different operating conditions of the system, a mathematical model of a gas turbine enabling the efficiency of the turbine unit and fuel consumption to be determined at nominal and part load of the machinery, and a mathematical model of a gas fan cooler enabling the efficiency of the cooler and electricity demand to be determined under different operating conditions of the system.

Environmental protection problems are substantively associated with treatment of wastewater flows of industrial facilities. Therefore, it is advisable to improve and introduce resource efficient technologies allowing to remove toxic compounds from the wastewater and to utilize wastewater treatment residues. In this research study, ferritization-based wastewater treatment was studied to remove chromium (VI) compounds, that belong to the first hazards class chemicals. Comparative efficiency of application of thermal and electromagnetic pulse activation of the ferritization process was evaluated. Appropriate experimental installations were assembled and the main parameters of the treatment process were identified: the ratio of iron (II) and chromium (VI) ions, the amplitude of the magnetic field, the frequency of electromagnetic pulses, the duration of the ferritization process, the temperature and pH of the reaction mixture. Expediency of using electromagnetic pulse activation of the reaction mixture has been studied and scientifically substantiated. Optimal values of the electromagnetic field amplitude for this activation method have been determined, that reach 0.01-0.09 T, as well as the ratio of concentrations of heavy metal ions Fe2+/Cr6+ = 10/1 for wastewater from the chromium electroplating production line. The treated water was shown to meet requirements for its reuse in production processes. The developed technology ensures introduction of a closed-circuit water supply at industrial facilities. High chemical stability of after-treatment sediments (residues) allows their safe disposal, in particular, their utilization in construction materials and paint coatings. Thus, this study contributes to improvement of environmental conditions at industrial facilities due to introduction of modern methods for processing toxic liquid waste flows, that also ensure rational use of water, reagents and energy at an industrial facility

The topic of the article results from the need to increase the capacity of municipal waste-to-energy (WTE) plants due to the growth of waste generation and the necessity to move away from the use of fossil fuels in district heating. The case study of such a plant was proposed. The city of Pruszków was selected for which the installation would cover its district heating base load. An economic analysis of such an investment was presented. The necessary input parameters were determined, i.e. the nominal thermal power of the installation, the required waste stream with appropriate properties, the stream available from the area around the city (taking into account existing thermal waste treatment installation), and the amount of substances released into the air with exhaust gases. Defined data were used to calculate the economical profitability of WTE plant taking into account revenues from heat sale and the gate fee for waste acceptance, as well as CAPEX and OPEX. The calculations took into account WTE plant’s accession to the EU emissions trading system (EU ETS), and were performed for two variants. One of them does not change heat prices or gate fees compared to the situation when WTE plant does not participate in the EU ETS. The second one transfers the cost of participation related to the EU ETS in 50% to heat consumers and 50% to waste suppliers. The IRR for the first variant was 2%, while for the second one it was 6%. It should be emphasized, however, that the calculations overestimated CAPEX due to the lack of current completed tenders for installations with similar capacity to the one analyzed in the article. These values also do not take into account preferred financing in form of non-refundable grants. A sensitivity analysis for IRR was prepared for the obtained higher result (6%). The factor that has the greatest impact on IRR is CAPEX, followed by the heat price and the gate fee. Changes in the above parameters in the range of +/- 20% cause changes IRR ranging from approx. 4 to approx. 9%. The summary indicates how the IRR value can be increased, as well as why the investment in WTE plant is beneficial for the local community and the environment.

Very high costs of constructions of large nuclear reactors and long terms of their construction diminished overall interest in this area. In response, a new strategy was introduced by nuclear reactors manufactures aimed at building smaller reactors, (small modular reactors- SMRs) which were expected to be faster to fabricate, safer to operate, and operate at lower cost per reactor. Many SMRs designs rely on a modular system, allowing customers to simply add modules to achieve a desired megawatt output (MWe). SMRs could potentially achieve safety advantages compared to large power plants and aim for a higher safety level especially through simplifications of design and development of active and passive safety systems. Especially passive safety systems will be dominated in SMRs. In article are also quoted world norms connected with safety of nuclear power plants