scholarly journals Analysis of a High-Voltage Room Quasi-Smoke Gas Explosion

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 601 ◽  
Author(s):  
Marit Sigfrid Bakka ◽  
Erling Kristian Handal ◽  
Torgrim Log
Keyword(s):  
Emergency Response ◽  
High Voltage ◽  
Air Separation ◽  
Production Plant ◽  
Smoke Alarm ◽  
Gas Explosion ◽  
Fire Dynamics ◽  
Power Circuit ◽  
Separation Unit ◽  
Control Cabinet

During an air separation unit shut-down in a methanol production plant, a stop signal was sent to the control cabinet of a synchronous motor for a booster compressor. The control cabinet stopped magnetizing the rotor, while the system logic ensured that the power circuit breakers for the start reactor coils were opened, in order to be ready for the next start-up. Unintentionally, the circuit breaker was still connected (i.e., power was let through the reactors for a prolonged time period), which led to extensive overheating. Subsequently, the central control room received an unaddressed sub-station smoke alarm, and plant operators were sent out to locate the possible source of smoke. The accessible rooms were searched, and traces of smoke were confirmed. The Emergency Response Organization (ERO) was mustered and, through inspection, the Emergency Response Team (ERT) realized that the smoke originated from a ground floor high-voltage room. Fire hoses were arranged for fire extinguishing, and the ERT withdrew to wait for the room to be electrically isolated. About one minute after briefly opening the only set of doors to the high-voltage room, flames were observed, and a quasi-smoke gas explosion violently forced both door blades open and released a substantial fire ball. Personnel had been in the risk zone shortly before the explosion, but luckily no personnel were hit by the slamming door blades or the emerging flames. The incident revealed several learning points related to improper maintenance, ambiguous smoke alarm, lack of flame detectors in the high-voltage room, insufficient risk understanding and training regarding electrically related fire incidents, and the absence of an automatic fire suppression system. In plants processing hydrocarbons, the safety focus regarding hydrocarbon fire and explosion risk is paramount. However, risks related to electrical accidents and compartment fire dynamics (e.g., backdraft and smoke gas explosion) should also be given proper attention.

An Analysis of On-Bord High-Voltage Converters of Single-Phase Alternating Current with Increased Miroelectric Power Factor

2020 ◽  
Vol 10 (10) ◽  
pp. 44-51
Author(s):  
Yury Yu. SKOROKHOD ◽  
◽  
Sehgey I. VOL’SKIY ◽  
Keyword(s):  
High Voltage ◽  
Single Phase ◽  
Input Current ◽  
Voltage Converter ◽  
Input Unit ◽  
Power Circuit ◽  
Electrical Systems ◽  
Static Converters ◽  
Technical Requirements

The power circuit arrangements of on-board high-voltage static converters fed from a 3000 V AC single-phase network that in the general case produce multi-channel AC and DC output voltages are considered. The basic technical requirements posed to such converters are formulated. The general structural diagram of high-voltage converters with improved electric power consumption quality is given. Possible power circuit arrangements for the high-voltage converter input unit based on single-phase input current correction devices are considered. A classification and criteria for comparative evaluation of the possible power circuit arrangements of these devices are proposed. The information presented in the article will be of interest for specialists engaged in designing on-board electrical systems involving high-voltage converters that must comply with strict requirements for the quality of consumed single-phase input current.

scholarly journals Power-to-Green Methanol via CO2 Hydrogenation—A Concept Study Including Oxyfuel Fluidized Bed Combustion of Biomass

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4638
Author(s):  
Simon Pratschner ◽  
Pavel Skopec ◽  
Jan Hrdlicka ◽  
Franz Winter
Keyword(s):  
Large Scale ◽  
Positive Impact ◽  
Renewable Energy Sources ◽  
Air Separation ◽  
Model Parameters ◽  
Processing Unit ◽  
Fluidized Bed Combustion ◽  
Separation Unit ◽  
Oxyfuel Combustion ◽  
Wind Park

A revolution of the global energy industry is without an alternative to solving the climate crisis. However, renewable energy sources typically show significant seasonal and daily fluctuations. This paper provides a system concept model of a decentralized power-to-green methanol plant consisting of a biomass heating plant with a thermal input of 20 MWth. (oxyfuel or air mode), a CO2 processing unit (DeOxo reactor or MEA absorption), an alkaline electrolyzer, a methanol synthesis unit, an air separation unit and a wind park. Applying oxyfuel combustion has the potential to directly utilize O2 generated by the electrolyzer, which was analyzed by varying critical model parameters. A major objective was to determine whether applying oxyfuel combustion has a positive impact on the plant’s power-to-liquid (PtL) efficiency rate. For cases utilizing more than 70% of CO2 generated by the combustion, the oxyfuel’s O2 demand is fully covered by the electrolyzer, making oxyfuel a viable option for large scale applications. Conventional air combustion is recommended for small wind parks and scenarios using surplus electricity. Maximum PtL efficiencies of ηPtL,Oxy = 51.91% and ηPtL,Air = 54.21% can be realized. Additionally, a case study for one year of operation has been conducted yielding an annual output of about 17,000 t/a methanol and 100 GWhth./a thermal energy for an input of 50,500 t/a woodchips and a wind park size of 36 MWp.

Techno-Economic Evaluation of Pressurized Oxy-Fuel Combustion Systems

2010 ◽  
Author(s):  
Jongsup Hong ◽  
Ahmed F. Ghoniem ◽  
Randall Field ◽  
Marco Gazzino
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Emissions ◽  
Power Plants ◽  
Carbon Dioxide Capture ◽  
Fuel Combustion ◽  
Economic Feasibility ◽  
Operating Conditions ◽  
Air Separation ◽  
Separation Unit ◽  
Coal Price

Oxy-fuel combustion coal-fired power plants can achieve significant reduction in carbon dioxide emissions, but at the cost of lowering their efficiency. Research and development are conducted to reduce the efficiency penalty and to improve their reliability. High-pressure oxy-fuel combustion has been shown to improve the overall performance by recuperating more of the fuel enthalpy into the power cycle. In our previous papers, we demonstrated how pressurized oxy-fuel combustion indeed achieves higher net efficiency than that of conventional atmospheric oxy-fuel power cycles. The system utilizes a cryogenic air separation unit, a carbon dioxide purification/compression unit, and flue gas recirculation system, adding to its cost. In this study, we perform a techno-economic feasibility study of pressurized oxy-fuel combustion power systems. A number of reports and papers have been used to develop reliable models which can predict the costs of power plant components, its operation, and carbon dioxide capture specific systems, etc. We evaluate different metrics including capital investments, cost of electricity, and CO2 avoidance costs. Based on our cost analysis, we show that the pressurized oxy-fuel power system is an effective solution in comparison to other carbon dioxide capture technologies. The higher heat recovery displaces some of the regeneration components of the feedwater system. Moreover, pressurized operating conditions lead to reduction in the size of several other critical components. Sensitivity analysis with respect to important parameters such as coal price and plant capacity is performed. The analysis suggests a guideline to operate pressurized oxy-fuel combustion power plants in a more cost-effective way.

Exergy Analysis of a Novel Cryogenic Concept for the Liquefaction of Natural Gas Integrated Into an Air Separation Process

2016 ◽  
Author(s):  
S. Tesch ◽  
T. Morosuk ◽  
G. Tsatsaronis
Keyword(s):  
Natural Gas ◽  
Power Consumption ◽  
Exergy Analysis ◽  
Primary Energy ◽  
Separation Process ◽  
Air Separation ◽  
Total Power ◽  
Separation Unit ◽  
Total Power Consumption ◽  
Liquefaction Temperature

The increasing demand for primary energy leads to a growing market of natural gas and the associated market for liquefied natural gas (LNG) increases, too. The liquefaction of natural gas is an energy- and cost-intensive process. After exploration, natural gas, is pretreated and cooled to the liquefaction temperature of around −160°C. In this paper, a novel concept for the integration of the liquefaction of natural gas into an air separation process is introduced. The system is evaluated from the energetic and exergetic points of view. Additionally, an advanced exergy analysis is conducted. The analysis of the concepts shows the effect of important parameters regarding the maximum amount of liquefiable of natural gas and the total power consumption. Comparing the different cases, the amount of LNG production could be increased by two thirds, while the power consumption is doubled. The results of the exergy analysis show, that the introduction of the liquefaction of natural gas has a positive effect on the exergetic efficiency of a convetional air separation unit, which increases from 38% to 49%.

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