Electrolysis Plant Research Articles

Korozija i zaštita betona u pogonu za proizvodnju katodnog bakra

The most complex type of corrosion in the plants of Copper Smelter and Refineries in Bor is present in the plant of Electrolytic Copper Refinery, where the solution of copper (II) sulfate causes the corrosion of concrete and concrete reinforcement as well as the applied steel materials. The processes of corrosion and destruction of concrete surfaces are particularly pronounced. Corrosion of concrete reinforcement is recognized as the main cause of degradation the concrete structure in many cases, both under the influence of sulfates and the influence of chloride ions. Regarding to this, the protection system also requires a knowledge on corrosion problems, both steel and concrete surfaces. The protection system applied in the Copper Electrolysis Plants consists of laying the acid-resistant plates in the epoxy mass, on a previously primed concrete base. This protection system provides minimum 10 years of a protection durability. This work will present the problems of corrosion of concrete structures that occur daily in the plants of Copper Electrolytic Refinery in Bor, the method they are solved and the method of applying the protection systems.

Demand response-oriented dynamic modeling and operational optimization of membrane-based chlor-alkali plants

Power-intensive processes can potentially provide significant demand response (DR) services. Modeling such processes for demand response is not trivial as models must depict plant transient properties under highly dynamic operation while remaining computationally efficient. We develop a demand response-oriented model for an important power-intensive process i.e., chlor-alkali production using membrane cells, and demonstrate the provision of fast demand response by an industrial-size plant. Through an extensive simulation and optimization case study, we show that the fast modulation of the cell power demand is possible without adverse impact on cell concentration and temperature. Additionally, the cell temperature dynamics are found to restrict the demand response capacity of the plant and must to be explicitly accounted for to support dynamic cell operation in DR scenarios. Substantial load curtailment during peak electricity price periods can be achieved and the energy cost to the electrolysis plant can be reduced.

Current converters with improved power characteristics

This article discusses development issue of semiconductor converters with the natural current external characteristics. The converter consists from a parametric current source, to the outputs of which are connected gated sets. The parametric source is a resonant circuit, which transforming electromotive force input system to the output system of currents. Here the resonant circuit in the current source provides an improvement in the power characteristics of the converter, so increasing energy efficiency indicators. This current converters use for supply most energy-intensive consumers with a steeply falling external characteristic (arc furnaces, electrolysis plants of non-ferrous metals, etc.), and also in electric drives with erection torque motor.

ANALYSIS OF LAYOUT SOLUTIONS OF ELECTROLYSIS SHOP OF HYDROGEN SUPERSTRUCTURE TAKING INTO ACCOUNT THE RELIABILITY AND EXPLOSION RISK

The article considers the layout solutions of the electrolysis shop of the hydrogen superstructure outside the territory of the nuclear power plant. To do this, an annual risk assessment was carried out taking into account the reliability and explosion risk for 1-4, 8 and 16 separate electrolysis shops installed on the site of the hydrogen superstructure. When taking into account equipment breakdowns, with possible explosions and fires in electrolysis plants, the risk due to fires and explosions was several times lower than the risk associated with equipment failures. Calculations showed that the transfer of electrolysis plants to increased hydrogen productivity in the event of failure of one of the cells is the best option in comparison with the reduction in the generation of electricity at the steam turbine installation of the hydrogen superstructure.

Dynamic performance analysis of a high-temperature steam electrolysis plant integrated within nuclear-renewable hybrid energy systems

A high-temperature steam electrolysis (HTSE) plant is proposed as a flexible load resource to be integrated with a light water reactor (LWR) in nuclear-renewable hybrid energy systems (N-R HESs). This integrated energy system is capable of dynamically apportioning electrical and thermal energy on an industrial scale to meet both grid demand and energy needs in the HTSE plant without generating greenhouse gases. A dynamic performance analysis of such a system is carried out to evaluate its technical feasibility and benefits, and safety operating under highly variable conditions requiring flexible output. To support the dynamic analysis, special emphasis is given here to the modeling and control design of the HTSE process, which employs planar solid oxide electrolysis cells, coupled to an LWR. The proposed model includes practical constraints, such as operating limits of equipment, and allows the simulation of transient response of the LWR/HTSE integration case with high penetration of renewable resources. Simulation results involving several case studies show that the HTSE integrated N-R HESs could lead to efficient utilization of clean energy generation sources at levels that maximize profits, i.e., steady-state operation of a nuclear reactor and high penetration of solar or wind energy without curtailment, by providing dispatchable electricity to the grid and producing alternative value-added products (hydrogen and oxygen). The results also indicate that the system can provide various types of ancillary services (i.e., regulation, operating reserves, and load following) to support grid stability while satisfying its operating constraints and control objectives; thus, it is capable of effectively and economically mitigating the increasing levels of dynamic variability and uncertainty introduced by renewables.

LIFE CYCLE ASSESSMENT OF THE HYDROGEN ENERGY FACILITY BY CRITERION FOR MAXIMUM LOAD FREQUENCY

The paper deals with the issue of providing the Nuclear Power Plant (NPP) by the base load in the nighttime offpeak load hours. In order to search a solution to this issue, we analyze the energy storage technologies including the hydroelectric power stations. Since the construction of this station is associated with various risks (technical, environmental, seismic, etc.), and their deployment in the immediate vicinity of Near Nuclear Power Plants is unacceptable. This implies the tariffs for the power supply from the grid transmission system may exceed the nuclear generating costs 3 or 4 times, and significantly affect the cost for the produced peak energy and competitive advantages of these stations. As more competitive technology of electric energy storage, the paper reviews the system based on utilizing hydrogen energy facilities with hydrogen and oxygen produced by water electrolysis due to excess power from nuclear power plants in the nighttime. The key advantage of these facilities is location in the vicinity of NPPs with the possibility of charging at the cost of the NPP energy. At the same time, hydrogen and oxygen production and their further utilization in the NPP steam cycle has the recurrent nature and connected with the daily startup and shutdown procedures of the main facilities. Thus, the aim of this research is to determine the life cycle of the main hydrogen energy facility under cyclic loads. The fatigue fracture theory is applied to analyze the performance of startup/shutdown cycles in the main hydrogen energy facility in combination with the NPP. We have conducted the estimation of fatigue crack growth depending on the load frequency for the critical components of electrolysis plants, compressors, metal hydrogen and oxygen storage tanks, as well as hydrogen-oxygen combustion chambers. The paper focuses on the impact of hydrogen corrosion on the rate of fatigue crack growth and proposes criterion defining the number of cycles occurred prior to the fracture extension process. Based on the criterion of maximum cycles prior to the fraction extension process, we have defined the boundaries for effective performance of the main hydrogen energy facility.

Economic assessment of hydrogen production from solar driven high-temperature steam electrolysis process

Abstract A key prerequisite for the hydrogen economy is cost-effective renewable hydrogen supply. This paper provides a framework for the thermodynamic and economic assessment of solar hydrogen production from the high-temperature steam electrolysis (HTSE) route. A system configuration for the solar-driven steam electrolysis plant is proposed. The thermodynamic and economic analysis is done for varying temperature and current density conditions of the solid oxide electrolyzer powered by concentrated solar (CSP) and photovoltaic (PV) power plants. Based on the expected reductions in the cost of plant components, the levelized cost of hydrogen (LCOH2) for the 2030 scenario is evaluated. Conditions for the viability of this route are checked by comparing the results with the polymer electrolyte membrane electrolysis (PEME) process. The optimum energy efficiency of a PV driven process increases from 9.1% at 873 K, 1500 A/m2 to 12.1% at 1273 K, 8000 A/m2. For the electrolyzer operating at 873 K, the optimum LCOH2 of 22 $/kg is obtained at 6000 A/m2. For the electrolyzer temperature of 1073 K, LCOH2 drops from 16 $/kg at 5000 A/m2 to 12.1 $/kg at 10000 A/m2. When compared to PEME, this route becomes viable beyond 973 K, 6000 A/m2 for PV and 923 K, 3000 A/m2 for CSP driven processes. With the current state of economics, this process is not competitive with the industrial steam methane reforming route. However, the cost target of 6–8 $/kg is achievable if the component costs reduce to 2030 level. Thus, the process has potential to be commercially viable and should be pursued further by creating prototype and pilot scale demonstrations.

REFHYNE project to install world's largest electrolysis plant in Shell German refinery

The REFHYNE consortium will build a new hydrogen electrolysis plant, the largest of its kind in the world, at the Shell Rheinland refinery in Germany. The 10 MW polymer electrolyte membrane (PEM) electrolyser will produce hydrogen primarily for the processing and upgrading of products at the refinery's Wesseling site.

Utilisation of alkaline electrolysers in existing distribution networks to increase the amount of integrated wind capacity

Hydrogen could become a significant fuel in the future especially within the transportation sector. Alkaline electrolysers supplied with power from renewable energy sources could be utilised to provide carbon free hydrogen for future hydrogen filling stations supplying Hydrogen Fuel Cell Vehicles (HFCV), or Internal Combustion Engines (ICEs) modified to burn hydrogen. However, there is a need to develop and use appropriate strategies such that the technology delivers greater economic and environmental benefits.In this work, the use of alkaline electrolysers to increase the capacity of integrated wind power in existing radial distribution networks is explored. A novel optimisation approach for sizing, placement and controlling electrolysers has been introduced, and its performance is assessed through modelling using a United Kingdom Generic Distribution System (UKGDS) case study. The controller objective is to dispatch alkaline electrolysers appropriately to maximise the total amount of profit from selling hydrogen and reduce the losses within the network while considering the realistic characteristics of pressurised alkaline electrolysis plants and satisfying the power system constraints. The impacts of increasing wind power capacity or the initial size of hydrogen filling stations on the results have been investigated and discussed.

European firms pursue H2 by electrolysis

Three European groups plan to individually build electrolysis plants that will use renewable energy to split water and make hydrogen. The groups say they are motivated by the opportunity to make production of hydrogen, now derived mostly via natural gas reforming, more sustainable. The chemical maker Evonik Industries has teamed up with Siemens in a two-year “artificial photosynthesis” research project that will use electrolysis powered by renewable electricity to convert water and carbon dioxide into hydrogen and carbon monoxide. In a subsequent step, microorganisms convert the carbon monoxide and hydrogen into specialty chemicals. The firms say they will bring a test plant on stream in Marl, Germany, by 2021. A second phase will likely involve building a commercial plant with a capacity of up to 20,000 metric tons per year, Evonik says. The initial project is set to receive $3.5 million from Germany’s Federal Ministry of Education & Research. A

Mathematical model for estimating variation in specific energy consumption with respect to capacity utilization for aluminum smelting plant

Primary aluminum production involves refining of bauxite to alumina and smelting of alumina to aluminum. Smelting is an energy-intensive process and consumes 85–90% of the electrical energy consumption. Under the National Mission on Enhanced Energy Efficiency (NMEEE), PAT (Perform, Achieve, and Trade) has been developed, which is a market-based mechanism to improve energy efficiency in the energy-intensive large industries. By the end of the first PAT cycle I, the energy savings of 0.456 million tons of oil equivalent/year is expected to be achieved, which is around 7% of the total national energy saving targets assessed under PAT. To achieve the targeted energy saving and to ensure unbiased implementation of the PAT scheme, normalization factors were developed by JNARDDC as a sector expert. This paper presents the methodology adopted for the formulation of normalization factor for Indian aluminum electrolysis plants.

Performance evaluation of hydrogen production based on off-peak electric energy of the nuclear power plant

The article investigates the efficiency of commercial hydrogen production by water electrolysis on the base of NPP excess energy with its additional purification higher than 99.9999%, considering its transport. The competitive high purity hydrogen release price has been determined as compared to the market price. Besides, the use of high duty electrolysis plants has been suggested. Moreover, the advantages of water electrolysis cyclic operation while consuming electric energy from NPP as compared to the continuous mode have been presented in the paper.

Analysis and Countermeasures of Wind Power Accommodation by Aluminum Electrolysis Pot-Lines in China

The unit energy consumption and its price have become the main obstacles for the future development of the aluminum electrolysis industry in China. Meanwhile, wind power is widely being abandoned because of its instability. In this study, a novel idea for wind power accommodation is proposed to achieve a win-win situation: the idea is for nearby aluminum electrolysis plants to absorb the wind power. The features of the wind power distribution and aluminum electrolysis industry are first summarized, and the concept of wind power accommodation by the aluminum industry is introduced. Then, based on the characteristics of aluminum reduction cells, the key problems, including the bus-bar status, thermal balance, and magnetohydrodynamics instabilities, are analyzed. In addition, a whole accommodation implementation plan for wind power by aluminum reduction is introduced to explain the theoretical value of accommodation, evaluation of the reduction cells, and the industrial experiment scheme. A numerical simulation of a typical scenario proves that there is large accommodation potential for the aluminum reduction cells. Aluminum electrolysis can accommodate wind power and remain stable under the proper technique and accommodation scheme, which will provide promising benefits for the aluminum plant and the wind energy plant.

AREVA H 2 Gen plans 60 MW electrolysis plant, wins ZBT order

AREVA H 2 Gen plans 60 MW electrolysis plant, wins ZBT order

Progress in Aluminum Electrolysis Control and Future Direction for Smart Aluminum Electrolysis Plant

The industrial aluminum reduction cell is an electrochemistry reactor that operates under high temperatures and highly corrosive conditions. However, these conditions have restricted the measurement of key control parameters, making the control of aluminum reduction cells a difficult problem in the industry. Because aluminum electrolysis control systems have a significant economic influence, substantial research has been conducted on control algorithms, control systems and information systems for aluminum reduction cells. This article first summarizes the development of control systems and then focuses on the progress made since 2000, including alumina concentration control, temperature control and electrolyte molecular ratio control, fault diagnosis, cell condition prediction and control system expansion. Based on these studies, the concept of a smart aluminum electrolysis plant is proposed. The frame construction, key problems and current progress are introduced. Finally, several future directions are discussed.

Degradation of Reinforced Concrete Structures of Aluminum Electrolysis Plants Subjected to Elevated Temperature and Cyclic Load

Technical papers describing the temperature related degradation of concrete are abundant, and serious damages often occurred in concrete structures subjected to high temperature such as metallurgy factories, although such occurrences were seldom made public. Concrete structures in aluminum electrolysis plants are generally subjected to high temperature emitted from electrolysis cells and cyclic load of heavy vehicles. Besides, hydrogen fluoride emitted from cells and stray current through reinforcement may cause deteriorating effects. In the case of an electrolysis plant built in Niigata in late 1960's, a part of passageway slab collapsed within a year of operation. A few years later, mesh shaped cracks on operation floor and shear cracks on floor beams and columns were observed. And an overall investigation on floor beams of 4 smelter buildings was carried out to determine the extent of deterioration, in 1972. The residual strength decreased linearly with operation term. The extent of strength reduction in "t" years' operation that we named "Deterioration Factor" and limit of lifetime were estimated. Countermeasures to reduce cyclic load and to reinforce floor beams were then taken, as well as the application of the Deterioration Factor to the next electrolysis plant in Shikoku Island. Details of renewed design of S-Electrolysis Plant and degradation of concrete are discussed. These aluminum electrolysis plants in Niigata and Shikoku have stopped operation in 1985 due to the withdrawal of the refining company, and existing smelter buildings have been diverted to another use. Although this paper presents rather retrospective cases, the authors wish this would be still helpful as a case study on degradation in concrete structure due to elevated temperature.

Electrochemical Impedance Spectroscopy on Industrially-Relevant Solid Oxide Electrolyzer Cell Stacks: A Powerful Tool for in-Situ Investigations of Degradation Mechanisms

In the current efforts of moving energy production to renewable sources, wind and solar energy are widely considered as the key technologies to cover our growing demands. However, the fluctuating nature of these sources requires a flexible energy system and storage technologies to ensure that energy services can be covered in a stable and affordable manner. One promising solution is the synthetic fuel production by solid oxide electrolyzers. Electricity can be stored in a power-to-gas process during times of excess electricity production and then further converted to liquid fuels for e.g. transportation, or at high demands converted back to electricity by either conventional power plants or fuel cells. One of today’s biggest hurdles for a successful commercialization of solid oxide electrolyzers is the stack’s lifetime with current industry targets in the order of five to ten years. To identify and quantify the different degradation mechanisms sensitive in-situ analysis tools are needed. On single cell level, electrochemical impedance spectroscopy (EIS) is a well-established diagnostics tool. On stack level EIS has been shown to be more difficult because of geometrical restrictions of the stack design and significantly lower resistances due to the larger active cell area. Nevertheless, it is becoming a more and more important technique for stack diagnostics. Here we present impedance spectroscopy results of two solid oxide stacks provided by Haldor Topsoe A/S. The first stack was a 14-cell stack (Delta design) specifically optimized for EIS measurements, while the other stack was an 8-cell stack (TSP-1 design), where impedance measurements were carried out without major modifications to the stack. The individual cell voltages were monitored simultaneously by EIS during up to 2000 hours in electrolysis within the ForskEL project 2015-1-12276 “Towards Solid Oxide Electrolysis Plants in 2020”, funded by Danish Energet.dk. The analysis provides valuable insight into the degradation processes which could not have been obtained by current-voltage-data alone.

Reagent Production Technology for Disinfection and Treatment of Drinking Water and Wastewater

There were presented principles of construction and design of complex electrolysis unit, generating on-site use at the same time chlorine-containing anolyte and sodium ferrate. Anolyte is used for water treatment in the municipal supply systems and industrial plants, and sodium ferrate to treat household and industrial wastewater, which after treatment can be discharge into environment without harm. There were substantiated proposed solutions of such unit to improve its performance and energy efficiency. There were offered practical solutions for the automation of anolyte and ferrate production process to control the parameters of the process and ensure its safety. Integrated electrolysis plant for the production of regents for the treatment of dinking water and wastewater has no domestic analogues and can provide competitive of domestic water treatment systems compared with foreign counterparts on the cost, performance and energy efficiency.

PERFORMANCE EVALUATION OF HYDROGEN PRODUCTION ON BASE OF THE OFF-PEAK ELECTRICITY OF ATOMIC POWER STATION

The article investigates efficiency of commercial hydrogen production by electrolysis of water on base of the surplus electricity of atomic power station with additional purification of his in membrane plant higher than 99.9999 percent and also with calculation cost of transportation. It is determined competitive sale price of hydrogen with high degree of purification by compare with market price. It is proposed to use the high power electrolysis plants. More - over, the article shows advantage of cyclical regime electrolysis of water at consumption of electricity from atomic power station in compare with stationary regime.

Black Liquor Electrolysis for Hydrogen and Lignin Extraction

Black liquor is a pulp mill effluent from wood cooking and has a solid content of 15-18% (weak black liquor), which is mostly lignin, an organic compound that finds wide applications in the market. Black liquor is currently used for steam generation purposes, by burning it, which is not an efficient process due to the undifferentiated combustion of the liquor, losing most of the lignin potential. Considering the world’s energy picture, it is essential to develop sustainable energy generation alternatives, including through waste recovery. Having this in mind, the current work focuses on the electrolysis of black liquor for energy recovery. The process has several economic and environmental advantages, as it simultaneously generates a clean fuel (hydrogen) at the cathode and a precipitated material with economic value (lignin) at the anode surface [1]. The generated hydrogen can be eventually fed to a fuel cell that partially powers the electrolysis plant, thereby decreasing the electricity costs. Herein, platinum (Pt), nickel (Ni), and AISI 304 stainless steel bulk electrodes are tested for black liquor electrolysis, both as anodes and as cathodes. Voltammetric methods are used to study the lignin anodic oxidation at the Pt, Ni and AISI 304 electrodes at temperatures ranging from 25 to 55 ºC. Kinetic and diffusional parameters are calculated (e.g., charge transfer and diffusion coefficients, number of exchanged electrons). The hydrogen evolution reaction in the black liquor is also evaluated at the same electrodes, with Pt and Ni showing the best performance. Activation energies are calculated for both electrochemical processes. Finally, a small-scale laboratory black liquor electrolyzer using Ni plates, both for anode and for cathode, is assembled and its operation parameters are evaluated, specifically the applied cell voltage and the electrolysis duration. The produced lignin is characterized by MIR and reveals a high purity compared with typical lyophilized and Klason lignin. [1] H.R. Ghatak, S. Kumar, P.P. Kundu, Int. J. Hydrogen Energy 33 (2008) 2904-2911.