Spelling suggestions: "subject:"alkaline electrolyzer"" "subject:"alkaline lectrolyzer""
1 |
Combined Coal Gasification and Alkaline Water Electrolyzer for Hydrogen ProductionHerdem, Munur Sacit January 2013 (has links)
There have been many studies in the energy field to achieve different goals such as energy security, energy independence and production of cheap energy. The consensus of the general population is that renewable energy sources can be used on a short-term basis to compensate for the energy requirement of the world. However, the prediction is that fossil fuels will be used to provide the majority of energy requirements in the world at least on a short-term basis. Coal is one of the major fossil fuels and will be used for a long time because there are large coal reservoirs in the world and many products such as hydrogen, ammonia, and diesel can be produced using coal.
In the present study, the performance of a clean energy system that combines the coal gasification and alkaline water electrolyzer concepts to produce hydrogen is evaluated through thermodynamic modeling and simulations. A parametric study is conducted to determine the effect of water ratio in coal slurry, gasifier temperature, effectiveness of carbon dioxide removal, and hydrogen recovery efficiency of the pressure swing adsorption unit on the system hydrogen production. In addition, the effects of different types of coals on the hydrogen production are estimated. The exergy efficiency and exergy destruction in each system component are also evaluated. Although this system produces hydrogen from coal, the greenhouse gases emitted from this system are fairly low.
|
2 |
Utilization of waste heat from hydrogen production : A case study on the Botnia Link H2 Project in Luleå, SwedenMiljanovic, Andrea, Jonsson, Fredrik January 2022 (has links)
The global hydrogen demand is steadily increasing, and one way of accelerating the green hydrogen supply is to stimulate the green hydrogen economy. Utilization of waste heat from hydrogen production can increase the profitability of produced green hydrogen. Therefore, the aim of this study is to propose a system for integration of waste heat on the district heating (DH) network in Luleå, Sweden. Furthermore, an economic evaluation of the proposed system was conducted. In this study, the system was developed and investigated for two cases i.e. for a PEM and alkaline electrolyzer with an installed capacity of 100 MW. A large-scale heat pump and a heat exchanger were further added to the system to integrate the waste heat on the DH-network, while simultaneously providing cooling to the electrolyzer stack. The system was modelled for static conditions in the software MATLAB, with retrieved hourly DH data from Luleå Energi. The results showed that 203 060 MWhth can be extracted from the PEM electrolyzer with a waste heat temperature of 79 oC, while 171 770 MWhth can be integrated on the DH network annually. For the alkaline electrolyzer, 310 630 MWhth can be extracted at a waste heat temperature of 80 oC, while 226 220 MWhth can be integrated on the DH annually. The overall system efficiency is 94.7 % and 88.4 % for PEM and alkaline connected systems, respectively. Furthermore, the Levelized Cost of Heat (LCOH) is 0.218 SEK/kWhth and 0.23 SEK/kWhth for a PEM and alkaline connected system, respectively. For future scenarios with fourth generation of DH-networks, it is predicted that the LCOH can reach 0.018 SEK/kWth for a PEM electrolyzer system, and 0.017 SEK/kWth for an alkaline electrolyzer system. One conclusion that can be drawn from this study is that the utilized heat from the proposed system is price competitive in comparison with other thermal energy sources.
|
3 |
Eletrolisador alcalino bipolar: avaliação de eletrodos a base de espuma de níquel usando energia fotovoltaica. / Bipolar alkaline electrolyzer: evaluation of electrodes based on nickel foam using photovoltaic energy.SANTIAGO, Natália de Oliveira. 14 March 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-03-14T21:37:10Z
No. of bitstreams: 1
NATÁLIA DE OLIVEIRA SANTIAGO - DISSERTAÇÃO PPGEQ 2015..pdf: 2885726 bytes, checksum: 42752aa08c69c959e3a3f1367b0e8e7a (MD5) / Made available in DSpace on 2018-03-14T21:37:10Z (GMT). No. of bitstreams: 1
NATÁLIA DE OLIVEIRA SANTIAGO - DISSERTAÇÃO PPGEQ 2015..pdf: 2885726 bytes, checksum: 42752aa08c69c959e3a3f1367b0e8e7a (MD5)
Previous issue date: 2015 / Capes / O uso desenfreado de combustíveis fósseis tem causado problemas climáticos
graves em todo o planeta, tais como o aquecimento global e a poluição do ar.
Além de seus efeitos negativos perante a natureza, estes acarretam custos
cada vez maiores de energia, devido à disponibilidade cada vez menor de
reservas de petróleo, de produção e de fornecimento. Nesse contexto o
hidrogênio vem a ser um vetor energético, devido a principalmente à sua alta
eficiência de conversão, reciclagem e natureza não-poluente. É um
combustível que não se encontra na natureza, mas ele pode ser facilmente
produzido. Este trabalho apresenta a produção do hidrogênio através da
eletrólise da água em meio alcalino (hidróxido de potássio, KOH) num reator de
tipo bipolar usando eletrodos de espuma de níquel. A avaliação do reator
eletrolítico, constituído de uma célula unitária, foi realizada pelo método
estatístico de superfície de resposta visando a otimização dos experimentos
através de dois planejamentos com duas variáveis dependentes: a tensão
aplicada e a concentração em porcentagem de massa do KOH. A resposta é
dada na forma de fluxo de hidrogênio (L/h) com o intuito de analisar o
comportamento do reator em diferentes situações. A partir dos parâmetros
analisados, foi encontrado o ponto ótimo de funcionamento do reator, obtido
com uma concentração de 16,6% em massa de KOH e uma tensão aplicada de
2,6 V, produzindo 0,841 L/h de H2, valor máximo obtido para ambos
planejamentos. / The society development is associated to the increasing use of fossil fuels,
creating serious climatic problems such as global warning and air pollution. The
ecological disasters, like floods and droughts, are a consequence of the
increasing release of CO2 and other greenhouse gases. Besides these
environmental problems, the costs relied to the extraction, production and
supply of oil, are increasing due to its availability. Changes are necessary to
control this situation and a way out is the use of another fuel in order to
guarantee sustainability. This fuel of the future can be hydrogen, mainly due to
its high conversion efficiency, recycling and non-polluting nature. It is
particularly attractive as a promising substitute of the fossil fuels. This work
presents the production of hydrogen by alkaline water electrolysis (potassium
hydroxide, KOH) using nickel foam based electrodes. The evaluation of the
electrolytic reactor, consisting of a unit cell, was performed by the statistical
method of response surface experiments through two plans with two dependent
variables: applied tension and KOH concentration. The response is the
hydrogen flow (L/h) in order to analyze the reactor behavior in different
situations. The optimum point of the reactor operation for both schedules was
obtained with a concentration of 16,6% KOH and an applied voltage of 2.6 V,
producing 0,841 L/h of H2.
|
4 |
Environmental Assessment of Electrolyzers for Hydrogen Gas ProductionSundin, Camilla January 2019 (has links)
Hydrogen has the potential to become an important energy carrier in the future with many areas of applications, as a clean fuel for transportation, heating, power generation in places where electricity use is not fit, etc. Already today hydrogen plays a key role in numerous industries such as petroleum refineries and chemical industries. There are different production methods for hydrogen. Today, natural gas reforming is the most commonly used. With the growing importance of green production paths, hydrogen production by electrolysis is expected to grow. Two main electrolyzer technologies are used today; alkaline and polymer electrolyte membrane electrolyzer. High-temperature electrolyzers are also interesting techniques, where solid oxide is under development and molten carbonate electrolyzers is researched. In this thesis, a comparative life cycle analysis was performed on the alkaline and molten carbonate electrolyzer. Due to inaccurate inventory data for the molten carbonate electrolyzer, those results are excluded from the published thesis. The environmental performance of the alkaline electrolyzer technology was compared to that of the solid oxide and the polymer electrolyte membrane electrolyzers. The system boundaries were set as cradle to gate. Thereby, the life cycle steps included in the study are raw material extraction, electrolyzer manufacturing, hydrogen production, and transports in between these steps. The functional unit was chosen as 100 kg produced hydrogen gas. The results show that the polymer electrolyte membrane electrolyzer has the lowest environmental impact out of the compared technologies. It is also determined that the lifetime and the current density of the electrolyzers have significant impact on their environmental performance. Moreover, it is established that electricity for hydrogen production has the highest environmental impact out of the electrolyzers life cycle steps. Therefore, it is important to make sure that the electricity used for hydrogen production derives from renewable sources. / Vätgas har potential att spela en viktig roll som energibärare i framtiden med många användningsområden, såsom ett rent bränsle för transporter, uppvärmning, kraftförsörjning där elproduktion inte är lämpligt, med mera. Redan idag är vätgas ett viktigt inslag i flera industrier, där ibland raffinaderier och kemiska industrier. Det finns flera metoder för att producera vätgas, där reformering av naturgas är den största produktionsmetoden idag. I framtiden spås vätgasproduktion med elektrolys bli allt viktigare, då hållbara produktionsprocesser prioriteras allt mer. Idag används främst två elektrolysörtekniker, alkalisk och polymerelektrolyt. Utöver dessa är högtemperaturelektrolysörer också intressanta tekniker, där fastoxidelektrolysören är under utveckling och smältkarbonatelektrolysören är på forskningsstadium. I det här examensarbetet har en jämförande livscykelanalys utförts på alkalisk- och smältkarbonatelektrolysören. På grund av felaktiga indata för smältkarbonatelektrolysören har dessa resultat uteslutits från den publika rapporten. Miljöpåverkan från den alkaliska elektrolysören har sedan jämförts med miljöpåverkan från fastoxid- och polymerelektrolytelektrolysörerna. Systemgränserna sattes till vagga till grind. De livscykelsteg som inkluderats i studien är därmed råmaterialutvinning, elektrolysörtillverkning, vätgasproduktion och transporter mellan dessa steg. Den funktionella enheten valdes till 100 kg producerad vätgas. Resultaten visar att polymerelektrolytteknologin har den lägsta miljöpåverkan utav de tekniker som jämförts. Resultaten påvisar också att livstiden och strömtätheten för de olika teknikerna har signifikant påverkan på teknikernas miljöpåverkan. Dessutom fastslås att elektriciteten för vätgasproduktion har högst miljöpåverkan utav de studerade livscykelstegen. Därför är det viktigt att elektriciteten som används för vätgasproduktionen kommer ifrån förnybara källor.
|
5 |
Hydrogen Production and Storage Optimization based on Technical and Financial Conditions : A study of hydrogen strategies focusing on demand and integration of wind power. / Optimering av vätgasproduktion och lagring utifrån tekniska och ekonomiska förutsättningar : En studie av vätgasstrategier med fokus på efterfrågan och integration av vindkraft.Langels, Hanna, Syrjä, Oskar January 2021 (has links)
There has recently been an increased interest in hydrogen, both as a solution for seasonal energy storage but also for implementations in various industries and as fuel for vehicles. The transition to a society less dependent on fossil fuels highlights the need for new solutions where hydrogen is predicted to play a key role. This project aims to investigate technical and economic outcomes of different strategies for production and storage of hydrogen based on hydrogen demand and source of electricity. This is done by simulating the operation of different systems over a year, mapping the storage level, the source of electricity, and calculating the levelized cost of hydrogen (LCOH). The study examines two main cases. The first case is a system integrated with offshore wind power for production of hydrogen to fuel the operations in the industrial port Gävle Hamn. The second case examines a system for independent refueling stations where two locations with different electricity prices and traffic flows are analyzed. Factors such as demand, electricity prices, and component costs are investigated through simulating cases as well as a sensitivity analysis. Future potential sources of income are also analyzed and discussed. The results show that using an alkaline electrolyzer (AEL) achieves the lowest LCOH while PEM electrolyzer is more flexible in its operation which enables the system to utilize more electricity from the offshore wind power. When the cost of wind electricity exceeds the average electricity price on the grid, a higher share of wind electricity relative to electricity from the grid being utilized in the production results in a higher LCOH. The optimal design of the storage depends on the demand, where using vessels above ground is the most beneficial option for smaller systems and larger systems benefit financially from using a lined rock cavern (LRC). Hence, the optimal design of a system depends on the demand, electricity source, and ultimately on the purpose of the system. The results show great potential for future implementation of hydrogen systems integrated with wind power. Considering the increased share of wind electricity in the energy system and the expected growth of the hydrogen market, these are results worth acknowledging in future projects.
|
Page generated in 0.0462 seconds