Thermodynamical motivation of the Polish energy policy

Basing on the first and second law of thermodynamics the fundamental trends in the Polish energy policy are analysed, including the aspects of environmental protection. The thermodynamical improvement of real processes (reduction of exergy losses) is the main way leading to an improvement of the effectivity of energy consumption. If the exergy loss is economically not justified, we have to do with an error from the viewpoint of the second law analysis. The paper contains a thermodynamical analysis of the ratio of final and primary energy, as well as the analysis of the thermo-ecological cost and index of sustainable development concerning primary energy. Analyses of thermo-ecological costs concerning electricity and centralized heat production have been also carried out. The effect of increasing the share of high-efficiency cogeneration has been analyzed, too. Attention has been paid to an improved efficiency of the transmission and distribution of electricity, which is of special importance from the viewpoint of the second law analysis. The improvement of the energy effectivity in industry was analyzed on the example of physical recuperation, being of special importance from the point of view of exergy analysis

Analysis of the cumulative exergy consumption of an integrated oxy-fuel combustion power plant

In order to analyze the cumulative exergy consumption of an integrated oxy-fuel combustion power plant the method of balance equations was applied based on the principle that the cumulative exergy consumption charging the products of this process equals the sum of cumulative exergy consumption charging the substrates. The set of balance equations of the cumulative exergy consumption bases on the ‘input-output method’ of the direct energy consumption. In the structure of the balance we distinguished main products (e.g. electricity), by-products (e.g. nitrogen) and external supplies (fuels). In the balance model of cumulative exergy consumption it has been assumed that the cumulative exergy consumption charging the supplies from outside is a quantity known a priori resulting from the analysis of cumulative exergy consumption concerning the economy of the whole country. The byproducts are charged by the cumulative exergy consumption resulting from the principle of a replaced process. The cumulative exergy consumption of the main products is the final quantity

System approach to the analysis of an integrated oxy-fuel combustion power plant

Oxy-fuel combustion (OFC) belongs to one of the three commonly known clean coal technologies for power generation sector and other industry sectors responsible for CO2 emissions (e.g., steel or cement production). The OFC capture technology is based on using high-purity oxygen in the combustion process instead of atmospheric air. Therefore flue gases have a high concentration of CO2 - Due to the limited adiabatic temperature of combustion some part of CO2 must be recycled to the boiler in order to maintain a proper flame temperature. An integrated oxy-fuel combustion power plant constitutes a system consisting of the following technological modules: boiler, steam cycle, air separation unit, cooling water and water treatment system, flue gas quality control system and CO2 processing unit. Due to the interconnections between technological modules, energy, exergy and ecological analyses require a system approach. The paper present the system approach based on the 'input-output' method to the analysis of the: direct energy and material consumption, cumulative energy and exergy consumption, system (local and cumulative) exergy losses, and thermoecological cost. Other measures like cumulative degree of perfection or index of sustainable development are also proposed. The paper presents a complex example of the system analysis (from direct energy consumption to thermoecological cost) of an advanced integrated OFC power plant

System effects of primary energy reduction connected with operation of the CHP plants

The paper is devoted to explication of one of the advantages of heat and electricity cogeneration, rarely considered in technical literature. Usually attention is paid to the fact that heat losses of the heat distribution network are less severe in the case of cogeneration of heat in comparison with its separate production. But this conclusion is also true in other cases when the internal consumption of heat is significant. In this paper it has been proved in the case of two examples concerning trigeneration technology with an absorption chiller cooperating with a combined heat and power (CHP) plant and CHP plant integrated with amine post-combustion CO2 processing unit. In both considered cases it might be said that thanks to cogeneration we have to do with less severe consequences of significant demand of heat for internal purposes

Optimal coefficient of the share of cogeneration in the district heating system cooperating with thermal storage

The paper presents the results of optimizing the coefficient of the share of cogeneration expressed by an empirical formula dedicated to designers, which will allow to determine the optimal value of the share of cogeneration in contemporary cogeneration systems with the thermal storages feeding the district heating systems. This formula bases on the algorithm of the choice of the optimal coefficient of the share of cogeneration in district heating systems with the thermal storage, taking into account additional benefits concerning the promotion of high-efficiency cogeneration and the decrease of the cost of CO2 emission thanks to cogeneration. The approach presented in this paper may be applicable both in combined heat and power (CHP) plants with back-pressure turbines and extraction-condensing turbines

Influence of biomass cofiring on the optimal coefficient of the cogeneration share in a district heating system

The paper presents a modified algorithm for choosing the optimal coefficient of the share of cogeneration in district heating systems taking into account additional benefits concerning the promotion of highefficiency cogeneration and biomass cofiring. The optimal coefficient of the share of cogeneration depends first of all on the share of the heat required for preparing the hot tap water. The final result of investigations is an empirical equation describing the influence of the ratio of the heat flux for the production of hot tap water to the maximum flux for space heating and ventilation, as well as the share of chemical energy of biomass in the fuel mixture on the optimal value of the share of cogeneration in district heating systems. The approach presented in the paper may be applied both in back-pressure combined heat and power (CHP) plants and in extraction-condensing CHP plants

Dobór optymalnej struktury elektrociepłowni gazowo-parowej opalanej hutniczymi gazami palnymi

CHP plants in ironworks are traditionally fired with low-calorific technological fuel gases and hard coal. Among metallurgical fuel gases blast-furnace gas (BFG) dominates. Minor shares of gaseous fuels are converter gas (LDG) and surpluses of coke-oven gas (COG). Metallurgical CHP plant repowering consists in adding a gas turbine to the existing traditional steam CHP plant. It has been assumed that the existing steam turbine and parts of double-fuel steam boilers can be used in modernized CHP plants. Such a system can be applied parallelly with the existing steam cycle, increasing the efficiency of utilizing the metallurgical fuel gases. The paper presents a method and the final results of analyzing the repowering of an existing metallurgical CHP plant fired with low-calorific technological fuel gases mixed with hard coal. The introduction of a gas turbine cycle results in a better effectiveness of the utilization of metallurgical fuel gases. Due to the probabilistic character of the input data (e.g. the duration curve of availability of the chemical energy of blast-furnace gas for CHP plant, the duration curve of ambient temperature) the Monte Carlo method has been applied in order to choose the optimal structure of the gas-and-steam combined cycle CHP unit, using the Gate Cycle software. In order to simplify the optimizing calculation, the described analysis has also been performed basing on the average value of availability of the chemical energy of blast-furnace gas. The fundamental values of optimization differ only slightly from the results of the probabilistic model. The results obtained by means of probabilistic and average input data have been compared using new information and a model applying average input data. The new software Thermoflex has been used. The comparison confirmed that in the choice of the power rating of the gas turbine based on both computer programs the results are similar.Tradycyjnie elektrociepłownie hutnicze są opalane niskokalorycznymi palnymi gazami technologicznymi w mieszaninie z pyłem węgla kamiennego. W mieszaninie gazów dominujący jest udział gazu wielkopiecowego. Znacznie mniejsze są udziały gazu koksowniczego i konwertorowego. Modernizacja elektrociepłowni hutniczej (tzw. repowering) polega na dobudowaniu do istniejącej struktury członu gazowego. W analizie założono możliwość wykorzystania istniejących turbin parowych oraz części dwupaliwowych kotłów parowych. Układ gazowo-parowy zostanie połączony równolegle z istniejącym obiegiem parowym, zwiększając tym samym efektywność energetyczną wykorzystania niskokalorycznych gazów hutniczych. W artykule zaprezentowano metodologię oraz wyniki końcowe przeprowadzonej analizy modernizacji istniejącej elektro- ciepłowni hutniczej opalanej niskokalorycznymi gazami hutniczymi w mieszance z pyłem węgla kamiennego. Bazowano przy tym na zbiorze danych wejściowych z lat 1996-2000. Z uwagi na probabilistyczny charakter danych wejściowych (min. wykres uporządkowany dostępności energii chemicznej gazu wielkopiecowego oraz wykres uporządkowany temperatury zewnętrznej) wykorzystano metodę Monte Carlo w celu doboru optymalnej struktury kombinowanego gazowo-parowego układu elektrocie- płowni wykorzystując do tego oprogramowanie Gate Cycle. Obliczenia optymalizacyjne zostały również przeprowadzone w oparciu o uśrednioną wartość strumienia energii chemicznej gazu wielkopiecowego dostępnego dla elektrociepłowni. Wyniki obliczeń podstawowych parametrów z tej analizy różnią się w nieznacznym stopniu od wyników uzyskanych za pomocą modelu probabilistycznego. Wyniki uzyskane zarówno z metody probabilistycznej, jak i bazującej na wartościach średnich danych wejściowych zostały porównane z rezultatami obliczeń w oparciu o nowy zestaw danych (lata 2005-2008), jak również nowy model utworzony w programie Thermotlex oraz Engineering Equation Solver. Obliczenia zostały przeprowadzone w oparciu o uśredniony strumień energii chemicznej gazu wielkopiecowego dostępnego dla elektrociepłowni. Zastosowane do doboru struktury modernizowanej elektrociepłowni hutniczej programy komputerowe Gate Cycle i Thermoflex dały zbliżone rezultaty

Life cycle assessment analysis of supercritical coal power units

This paper presents the Life Cycle Assessment (LCA) analysis concerning the selected options of supercritical coal power units. The investigation covers a pulverized power unit without a CCS (Carbon Capture and Storage) installation, a pulverized unit with a "post-combustion" installation (MEA type) and a pulverized power unit working in the "oxy-combustion" mode. For each variant the net electric power amounts to 600 MW. The energy component of the LCA analysis has been determined. It describes the depletion of non-renewable natural resources. The energy component is determined by the coefficient of cumulative energy consumption in the life cycle. For the calculation of the ecological component of the LCA analysis the cumulative CO2 emission has been applied. At present it is the basic emission factor for the LCA analysis of power plants. The work also presents the sensitivity analysis of calculated energy and ecological factors

Thermodynamic simulation analysis of a multifuel CHP plant basing on the technological diagram of Avedore unit 2

The paper presents the results of a simulative thermodynamic analysis of a multifuel CHP plant basing on the technological diagram of Avedore 2. Calculations have been carried out for the operation of Avedore 2 plant in the district heating mode. Several variants of simulation have been considered, determined by the choice of operation of the respective plants, viz. main boiler fired with natural gas, main and biomass boiler, main boiler and GT plant, joint operation of the main and biomass boiler and GT plant, main boiler (fired with heavy fuel oil or/and wood chips) and biomass boiler and GT plant. For each variants a diagram of iso-fuel curves has been developed, illustrating the variability of useful effects (power output and district heat) at various loads of the CHP steam part. In case of the variant in which the main boiler and GT are in operation with natural gas as fuel the exemplary energy indices were determined