Characteristics modeling for supercritical circulating fluidized bed boiler working in oxy-combustion technology

Among the technologies which allow to reduce greenhouse gas emission, mainly carbon dioxide, special attention deserves the idea of ‘zeroemission’ technology based on boilers working in oxy-combustion technology. In the paper the results of analyses of the influence of changing two quantities, namely oxygen share in oxidant produced in the air separation unit, and oxygen share in oxidant supplied to the furnace chamber on the selected characteristics of a steam boiler including the degree of exhaust gas recirculation, boiler efficiency and adiabatic flame temperature, was examined. Due to the possibility of the integration of boiler model with carbon dioxide capture, separation and storage installation, the subject of the analysis was also to determine composition of the flue gas at the outlet of a moisture condensation installation. Required calculations were made using a model of a supercritical circulating fluidized bed boiler working in oxy-combustion technology, which was built in a commercial software and in-house codes

Kierunek transformacji energetyki zgodnie ze ścieżką Coal-to-Nuclear. Założenia i cele projektu DEsire

Z początkiem kwietnia br. rozpoczął się projekt badawczy o akronimie DEsire. Głównym celem projektu jest opracowanie planu dekarbonizacji polskiej energetyki zawodowej na drodze wykorzystania reaktorów jądrowych generacji III/III+ oraz IV. Realizacja siedmiu zadań badawczych ma pozwolić na ocenę zyskującej na świecie popularność ścieżki transformacji Coal-to-Nuclear, przede wszystkim w kontekście potencjału krajowego. Projekt realizowany jest w ramach konsorcjum utworzonego przez pięć podmiotów: Politechnikę Śląską, Ministerstwo Klimatu i Środowiska, Energoprojekt-Katowice SA, Instytut Chemii i Techniki Jądrowej oraz Fundację Instytut Sobieskiego. Finansowanie projektu uzyskano w ramach VI konkursu Narodowego Centrum Badań i Rozwoju „Gospostrateg”

The potential of using hydrogen in the Polish energy system

Realizacja strategii dekarbonizacji polskiej gospodarki wymaga wprowadzenia do eksploatacji nowych technologii energetycznych, w tym technologii wodorowych. W rozdziale zawarto informacje o potencjalnych możliwościach wykorzystania wodoru w procesach generacji elektryczności i ciepła. Struktura pozyskiwania w Polsce zarówno energii elektrycznej, jak i pierwotnej, istotnie różni się od struktury charakterystycznej dla UE. Istnieje znaczny potencjał jej dywersyfikacji. We wszystkich działach energetyki zastosowanie wodoru może ułatwić uzyskanie celów klimatycznych i ekonomicznych (efektywnościowych). Ostateczne scenariusze technologiczne wytwarzania wodoru będą zależeć od stanu rozwoju OZE i ekonomiczności poszczególnych rozwiązań. Ważne jest pytanie, który scenariusz jest najprawdopodobniejszy w Polsce. Biorąc pod uwagę aktualny potencjał OZE oraz przewidywany ich rozwój do 2040 r., wydaje się, że elektrolityczna produkcja wodoru w Polsce z wykorzystaniem OZE nie będzie zbyt wysoka. Założenie 2 GW mocy elektrolizerów w 2030 r. w Polskiej strategii wodorowej jest bardzo (zbyt) optymistyczne (Niemcy 5 GW, Hiszpania 4 GW). Trudno natomiast przesądzić, jakie będzie upowszechnienie innych technologii wytwarzania, zwłaszcza trudno ocenić udział CCS. W najbardziej optymistycznym scenariuszu sformułowanym dla UE udział wodoru w 2050 r. w końcowym zużyciu energii wynosi 24% (2251 TWh) (Hydrogen… 2019). Przewidywana struktura jego zużycia to: 112 TWh (około 5%) – wytwarzanie elektryczności, bilansowanie systemu (power generation, buffering, sektor 1); 675 TWh (30%) – transport (sektor 2); 579 TWh (25,7%) – ogrzewanie i energia dla mieszkalnictwa (heating, power for buildings, sektor 3); 237 TWh (10,5%) – energia dla procesów przemysłowych (industry energy, sektor 4); 257 TWh (11,4%) – nowe zastosowania przemysłowe (new industry feedstock, sektor 5); 391 TWh (17,4%, sektor 6) – istniejące obszary zastosowań przemysłowych (existing industry feedstock). Ten procentowy udział w zakresie sektorów 1 i 3 przeniesiony na grunt Polski można uznać za rozsądny. Aczkolwiek bardzo szkodliwa z ekologicznego punktu widzenia struktura zużycia energii w gospodarstwach domowych w Polsce w chwili obecnej, podpowiada zwiększenie udziału wodoru w tym sektorze

Evaluation of electricity generation subsystem of Power-to-Gas-to-Power unit using gas expander and heat recovery steam generator

In the last years, the European energy policy has required to increase the share of renewable energy sources in the national energy systems. It is important to diversify the energy system not to bring about a global crisis resulting from the fundamental lack of electricity. Unfortunately renewable sources are unstable and generate several problems during integration with the power grid. The solution is to store additional energy produced from renewable sources. In this way, energy can be used when there is a need. The paper discusses the study of the Power-to-Gas-to-Power installation using electrolysis and methanation processes at the energy storage stage and gas expanders during energy discharges. In addition, a part of the Heat Recovery Steam Generation installation has been implemented. The purpose of the work was to determine the impact of a given Heat Recovery Steam Generation installation on the efficiency of the entire installation and flue gas temperature at the outlet from Heat Recovery Steam Generator

Modeling of influence of vibration on intensification of heat transfer within the absorber of the vacuum solar collector

Due to escalating role of mitigation of climate change in power and energy sector, power units based on renewable energy sources (RES) became vital part of global power and heat market, including distributed heat generation as well. Significant number of such installations belong to individual users, commonly using solar collectors to prepare domestic hot water directly at their sites. However, the vitally variable solar irradiance makes the solar energy difficult in efficient harvesting considering long time period. Thus, maximization of power gain from single solar absorber, when the solar radiation flux is temporarily high, might lead to further rise in overall, year-averaged efficiency of such units. The paper concerns modelling of intensification of heat transfer, taking place within the absorber of a vacuum solar collector, due to insertion of vibrating element inside the thermal oil canal, compared to static turbulization method. Different geometries of vibrating elements and amplitudes of oscillatory motion, as well as heat carriers, are investigated using commercially available CFD software. Results indicate rise in solar power acquired within the absorber using vibrating elements, with essential difference between circulating media, and suggest vital benefits from utilization of static turbulizing devices

Study of Twisted Tape Inserts Segmental Application in Low-Concentrated Solar Parabolic Trough Collectors

This article presents the results of an analysis of heat enhancement intensification using twisted tapes in linear absorbers for low-concentration parabolic trough collectors, a technology frequently considered as a supplementary energy source for industrial heat production. This contribution proposes a segmented application of different twisted tapes to intensify heat absorption. A 33.7 mm tubular absorber placed in the collector focal point with an aperture of 1.8 m was selected. The temperature range of the heat transfer fluid was chosen at 60–250 °C. The impact of inserts with twisted ratios of 1, 2 and 4 on system operation was analysed using the Ansys Fluent and mathematical model. The models used were validated based on experimental results from a parabolic trough collector with solar simulator test bench. The results indicated that for the range of mass flow between 0.15–0.3 kg/s, the most optimal is applying twisted ratio 1, except for the highest-temperature section. In this section, it is more optimal to use an insert with a twisted ratio 2, due to the lower need for pumping and the higher efficiency increment. The long-term analysis for the case study plant indicated that the proposed approach increased power gain by 0.27%

An experimental study on parabolic trough collector in simulated conditions by metal-halide solar radiation simulator

The utilization of solar radiation to obtain high-temperature heat can be realized by multiplying it on the illuminated surface with solar concentrating technologies. High-temperature heat with significant energy potential can be used for many technological purposes, e.g. the production of heat, cold or electricity. The following paper presents the results of the experimental study, on the operation of the parabolic linear absorber in the parabolic concentrator solar system. The parabolic mirror with an aperture of 1 m and a focal length of 0.25 m focuses the simulated radiation onto a tubular absorber with a diameter of 33.7 mm, which is placed in a vacuum tube. The length of the absorber is 1 m. The installation is illuminated by the solar simulator, which allows to carry out tests under constant and repeatable conditions. The simulator consists of 18 metal halide lamps, with a nominal power of 575 W each with a dimming possibility of up to 60%. The paper presents preliminary results of heat absorption by the analysed absorber, temperature increment, collected heat flux, and the pressure drop crucial for the optimization of the absorber geometry