Supercritical Steam Research Articles

Rosmarinus plants: Key farm concepts towards food applications.

Rosmarinus species are aromatic plants that mainly grow in the Mediterranean region. They are widely used in folk medicine, food, and flavor industries and represent a valuable source of biologically active compounds (e.g., terpenoids, flavonoids, and phenolic acids). The extraction of rosemary essential oil is being done using three main methods: carbon dioxide supercritical extraction, steam distillation, and hydrodistillation. Furthermore, interesting antioxidant, antibacterial, antifungal, antileishmanial, anthelmintic, anticancer, anti-inflammatory, antidepressant, and antiamnesic effects have also been broadly recognized for rosemary plant extracts. Thus the present review summarized data on economically important Rosmarinus officinalis species, including isolation, extraction techniques, chemical composition, pharmaceutical, and food applications.

Classical and advanced exergy-based analysis of a 750 MW steam power plant

ABSTRACT Both the conventional (classic) and advanced exergetic analytical methods were used to investigate the improvement potentials of a pulverised coal-fired 750 supercritical steam power plant. The results show that the subsystem that contributed the most to exergy destruction is the condenser (CND) at about 1.25% and closely followed by the boiler at 1.23%. Furthermore, the data obtained from the present study show that the dominant contributor to the overall exergy destruction in each of the subsystems was the endogenous part of exergy destruction, . In addition, the results show that steam turbines, especially TB1, TB4, TB5, TB6, TB7 to TB17, the condenser and the boiler would benefit immensely by improving their avoidable endogenous exergy destructions. This investigation also shows that the overall unavoidable exergy destruction within the entire power plant was about 42.8%, while the potential for improving the entire power plant was approximately 2.5%. Other important results from this study are comprehensibly documented in the conclusion section.

Comparison of Different Extraction Techniques of Zingiber officinale Essential Oil

Abstract This study aims to find the best conditions for the extraction of Zingiber officinale essential oil using the supercritical fluid extraction (SFE), steam distillation (SD) and hydrodistillation (HD) techniques, regarding the maximum oil yield. For the HD technique is evaluated the best ratio between plant mass and water volume and for SFE and SD the pressure condition was investigated. Principal Component Analysis (PCA) was used to evaluate the similarity between the composition of the essential oil in different pressures and extraction methods. The experimental extraction curve was plotted and three different mathematical models were used to fit the data for SD and SFE methods, obtaining the relevant mass transfer parameters. The essential oil compounds were identified by gas chromatography coupled with mass spectrometry (GC-MS), being α-zingiberene the main component with different contents (from 11.9 to 28.9%). The best condition for the SFE was 100 bar, 40 °C (0.0508 goil/gplant) with 19.34% of α-zingiberene; for the SD, 3 bar (133 °C) (0.00616 goil/gplant) with 28.9% of α-zingiberene; and HD, the volume of 750 mL (0.006988 goil/gplant) with 15.70% of α-zingiberene, all measured on a dry basis.

Energy and Exergy Analyses of Chemical Looping Combustion based 660 MWe Supercritical Coal Fired Power Plant

Coal still remains to be the major resource for power production in many countries. Supercritical (SupC) steam generated coal-fired power plants (CFPPs) are found to be superior to subcritical steam generated plants in terms of the overall plant efficiency. Chemical looping combustion (CLC), which is an indirect combustion between fuel and air, is an innovative, inherent CO2 capture and recent technology for power production. In this study, two cases - conventional SupC CFPP without CO2 capture and CLC-based SupC CFPP for high-ash Indian coal have been simulated. Detailed energy and exergy analyses are conducted for both the cases and compared. The study shows that CLC-based capture technology has less energy penalty with Fe2O3 oxygen carrier and little energy gain with CuO and NiO carriers compared to conventional plant without CO2 capture. This study demonstrates the superiority of CLC-based SupC CFPP for CO2 capture over the conventional plant.

Peculiarities of the Use of Heat-Resistant Steels for Steam Pipelines and the Elements of Their Systems

Power generating units of heat and power plants equipped with steam boilers that have supercritical and high steam parameters and the system of steam pipelines produce the major portion of electric power in Ukraine. This scientific paper describes the peculiarities of the use of heat-resistant pearlitic steels of 12Х1МF, 15Х1М1F, 12Х2МFSR grades and others. These steels are used to manufacture the elements for the steam pipelines of thermal power plants whose service life has already run out and it is a vital problem at the moment. This scientific paper looks into the reasons for the appearance of damages and degraded operating performances of the welded pipe junctions of steam pipelines. The research data obtained during the studies of the structure and mechanical properties of the welded junctions of steam pipelines have been given. Consideration was given to the factors that affect welded junctions during their long-term operation. It was established that the welded junctions made of heat-resistant pearlitic steels degrade during their long-term operation following the creep crack formation mechanism. It was established that the welded junctions of steam pipelines with the accrued operating time of 270.000 hours and an increased number of the start-stop cycles of power generating units are characterized by an increased probability of faults following the fatigue mechanism. It depends to a great extent on the local concentration of stresses in the structures of welded junctions and their structural state.

COMPARISON OF LAURUS NOBILIS EXTRACTS COMPOSITION OBTAINED BY MICROWAVE EXTRACTION, SUPERCRITICAL FLUID EXTRACTION AND STEAM DISTILLATION

A comparison of chemical composition of bay laurel extracts obtained by microwave extraction, supercritical fluid extraction and steam distillation was performed. Microwave extraction and steam distillation were shown to give similar essential oils. Microwave extract contains more monoterpenoid components, especially hydrocarbons. Steam distillation oil contains more sesquiterpenoid compounds, mostly oxygenated. SFE extract composition differs substantially from the ones obtained by two other methods. According to GC-MS data they contain much more sesquiterpenoid components, namely sesquiterpene lactones. This makes SFE a perspective candidate for isolation of biologically active compounds from laurel leaves. However, apart from valuable compound SFE extracts also contain substantial amounts of waxes as well as large quantities of some non-volatile component undetectable via GC-MS. In order to implement SFE into the practice of laurel processing one has to develop an approach for the fractionation of SFE extracts allowing isolating sesquiterpene lactone enriched fraction.

Distribution characteristics of salt-out particles in steam turbine stage

Exploring the distribution characteristics of salt-out particles on the blade surface is one of the most urgent problems for supercritical steam turbine. To obtain more practical distribution characteristics of salt-out particles in the steam turbine stage, the population balance model is loaded based on Eulerian multiphase model to simulate the real existed microscopic behaviors of salt-out particles such as nucleation, growth, aggregation and breakage. The results show that along the axial direction the number of salt-out particles gradually decreases and a ladder-like distribution is observed both on the stator and rotor blades. For the stator blade, a critical position which is 62.9% of the axial chord length occurs before which the diameter of salt-out particles on the pressure surface is greater than that on the suction surface, while after that the situation is opposite; for the rotor blade, a different critical position which is 81.1% of the axial chord length occurs. Along the axial direction the volume fraction of particles declines in the entrance area, fluctuates in the middle area on the stator blade, and on the pressure surface of rotor blade, a peak position of the volume fraction is consistent with the maximum turbulence intensity and particle diameter.

Modeling and performance analysis of subcritical and supercritical coal-fired power plants with biomass co-firing and CO2 capture

Coal-fired power plants are the largest source of carbon dioxide (CO2) emissions into the atmosphere, and these emissions can be effectively reduced by improving the efficiency of the plants, co-firing sustainably grown biomass and applying carbon capture and storage technologies. In this study, the energy and environmental performances of both subcritical (SubC) and supercritical (SC) pulverized coal-fired power plants with biomass co-firing and integrated with an advanced amine-based postcombustion CO2 capture system were evaluated and compared. The impact of biomass (hybrid poplar) addition was investigated at different co-firing ratios varying up to 30% on a heat input basis. All plant configurations were modeled and simulated with Aspen Plus process simulation software. The results show that the use of a SC steam cycle has a positive impact on the energy and environmental performance of the investigated plants, improving the efficiency by 2.4% points and reducing the total fuel consumption and CO2 emissions by 6% in comparison to those of the SubC cases. Biomass co-firing has a negative impact on the energy performance of plants while significantly reducing fossil-based carbon emissions. The reduction of net CO2 emissions is almost proportional to the biomass percentage in the feed. At 30% biomass co-firing, the net plant efficiency is reduced by approx. 1% point, while the net CO2 emissions are 28% lower than those in coal-fired only plants. The introduction of CO2 capture has a major impact both on the emissions generated and on the energy efficiency. Depending on the plant type and co-firing ratio used, the net plant efficiencies are 8.7–9.3% points lower than those of non-capture cases. The net CO2 emissions achieve negative values when carbon is captured from the biomass co-firing plants.

ИССЛЕДОВАНИЯ ТЕПЛООБМЕНА В ПУЧКАХ ТВЭЛОВ ПРИ СВЕРХКРИТИЧЕСКОМ ДАВЛЕНИИ ВОДЫ

Calculations to substantiate the characteristics of a reactor cooled by water with supercritical steam parameters and an adjustable neutron spectrum require clarification of data on heat transfer characteristics. The features and data on heat transfer in round pipes and rod bundles at supercritical pressures (SCP) are considered. In analysis of hydrodynamics and heat transfer dates with the flow of water of supercritical parameters in round pipes, an area of both more intense and degraded convective heat transfer was detected compared to subcritical pressures. It is assumed that one of the reasons for the deteriorated heat exchange is the presence of a near-wall layer consisting of a "gas" phase with low thermal conductivity and a central flow region in the form of a liquid-like phase having a lower temperature. A brief review of data on heat transfer in round tubes and rod bundles with SCP is presented. Since experiments on water are complex and expensive, many results, including the SSC RF - IPPE, were obtained on model media (CO2 and freon-12). Shown that despite the diversity of recommendations on the boundary regime with the deterioration of heat transfer, the proposed ratios give a different dependence of the heat flux density on the mass velocity. They do not consider the influence of such parameters as pressure, channel geometry, temperature of heat exchange surface, etc., they are obtained for a narrow range of parameters. And only extensive analytical studies of Yu.A. Zeigarnik et al. (JIHT RAS, NRU "MEI") allowed to summarize the data on heat transfer in round pipes at SCP. Only limited data was obtained by Russian, Ukrainian and Chinese specialists in heat transfer in bundles with a small number of pipes. The results of Chinese experts have shown that heat transfer in rod bundles at supercritical water pressures is higher and more stable than when water moves in pipes and annular channels. In close bundles, the deterioration of heat transfer occurred at low mass velocities and high heat fluxes, and in widespread deterioration of heat transfer was not observed. The growth of heat transfer in the rod bundles is promoted by mixing with spacer and mixing grids, which destroy the wall barrier layer, which prevents the transfer of heat under supercritical pressure from the wall to the center of the flow. The accumulation of new experimental data and additional analysis of research are necessary. A description and technical characteristics of the thermo-hydraulic facilities of the SCP on water (SVD-1 and SVD-2) and freon-12 (STF) available at SSC RF - IPPE is provided. The results of experiments at SSC RF - IPPE and technical approach and methodology of future experiments in hydrodynamics and heat transfer at SCP is presented and discussed.

Energy assessment of coal-fired steam power plant, carbon capture, and carbon liquefaction process chain as a whole

This study evaluates a chain of units that consist of a supercritical steam power plant, CO2 capture unit, and CO2 liquefaction unit, in terms of energy production and usage. The steam power plant is fueled by Illinois no. 6 bituminous coal and designed to deliver a gross electrical power of 600 MW. Energy performance of two different solvents (30% wt. Monoethanolamine and 40% wt. Piperazine) were considered for CO2 capture unit, and a sensitivity analysis was done to ascertain the effect of Lean/Rich heat exchanger minimum temperature approach on energy consumption of the reboiler. Two separate liquid states of CO2 (19.7 bar, −20 °C and 26.5 bar, −10 °C), which their ship-based transportation feasibility was studied by Global Carbon Capture and Storage Institute, was considered as the state of produced CO2 stream. Three conventional and one novel liquefaction processes were evaluated to deliver CO2 stream at aforementioned liquid states. While both of simulated CO2 capture units are thermally integrated with the steam power plant, just the novel case of liquefaction process is integrated with the steam power plant. According to the results, the reboiler in 40% wt. Piperazine case was ascertained to have 11% less energy consumption than that of 30% wt. Monoethanolamine case. The novel liquefaction process shows the best energy performance, and its equivalent sacrificed electrical energy is the lowest among all. Comparison of all possible chains of cases in this study (19 possibilities) gives a deep insight about affecting parameters of carbon capture and liquefaction in post-combustion.

Composition analysis,antioxidative and antibacterial activities comparison of agarwood oils extracted by supercritical and steam distillation

Agarwood is a traditional and precious medicinal material and natural spice in China and other southeast Asian countries.As the head of all spices,agarwood has many pharmacological activities such as analgesia,antidiarrheal,anti-inflammatory and antibacterial effects. Due to its high price and scarce resources,there were just a few previous studies on it,mainly focusing on the chemical compositions of the agarwood essential oil and solvent extract mixture. The components of agarwood oils obtained by supercritical extraction and steam distillation were analyzed by using Gas Chromatography-Mass Spectrometer( GC-MS),and then the agarwood oils compositions and contents were compared between the traditional extraction method and the recently emerging supercritical extraction method. Antioxidant experiments of scavenging DPPH,ABTS,hydroxyl radical,total reducing power and MIC experiments of five kinds of tester strains such as staphylococcus aureus were combined to illustrate the differences between these two kinds of agarwood oils in terms of antioxidant and bacteriostatic activities. The results showed that the main components of agarwood oil were sesquiterpenoids( 68. 68%) in steam distillation extraction method,but sesquiterpenoids( 23. 78%) and chromones( 29. 42%) in supercritical extraction method. Fourteen common components included benzyl acetone,α-santalol,γ-eudesmol,agarospirol and guaiol etc. The antioxidant activity and inhibitory MIC of agarwood oils in supercritical extraction method were better than those in steam distillation method,and the inhibitory effect of agarwood oil on the growth of bacillus subtilis was found for the first time.

Comparison and sensitivity analysis of the efficiency enhancements of coal-fired power plants integrated with supercritical CO2 Brayton cycle and steam Rankine cycle

The supercritical CO2 (SCO2) power cycle, which is highly efficient and cost effective and features a compact structure, is expected to replace steam Rankine cycle and bring technological revolution to coal-fired power plants. To obtain the quantitative energy saving potentials of the SCO2 power cycle, this study compared the thermodynamic performances of coal-fired power plants with SCO2 cycle and 10 in-service coal-fired power plants with steam as the working fluid. The efficiencies of 538 °C, 566 °C, and 600 °C typical power plants were increased by the SCO2 cycle by 2.52%, 2.39%, and 2.84%, respectively. Exergetic analysis revealed that the decrease in heat transfer irreversibility in the boilers mainly caused the efficiency enhancement. Then, the main devices’ performance parameters, including the isentropic efficiency of the compressor, isentropic efficiency of the turbine, pressure drops of the heat exchangers, regenerator terminal temperature difference, and leakage ratio, were analyzed in terms of their sensitivity to the efficiency enhancement of coal-fired power plants integrated with the SCO2 cycle. The influence of these parameters on the internal irreversibility of coal-fired power plants was also studied. With a 600 °C power plant as an example, the energy saving limits of the main devices’ parameters of SCO2 cycle in comparison with the steam Rankine cycle are as follows: the compressor isentropic efficiency exceeded 75%, the turbine isentropic efficiency exceeded 86%, the pressure drop of the heat exchanger was less than 0.35 MPa, the temperature difference of the regenerator terminal was less than 21 °C, the leakage ratio was less than 2.5% when the leakage was not recovered, and the leakage ratio was less than 16% when the leakage was recovered.

Numerical investigation on aerodynamic characteristics of exhaust passage with consideration of multi-factor components in a supercritical steam turbine

Heat transfer and vacuum in the condenser are affected by the flow characteristics in the low-pressure steam turbine exhaust passage. In this study, the Eulerian-Eulerian equilibrium two-phase model is applied to investigate the contribution of multi-factor components on aerodynamic performance of twin exhaust passage. Results show that the share of steam phase is reduced in the exhaust passage with consideration of the built-in pipelines. Total-pressure loss in the exhaust hood is about four times of that in the throat. The sensitivity of local loss existing in the exhaust hood on the whole loss is higher than that in the throat. Considering the factors of LSBs and pipelines, both the static-pressure recovery coefficient of 15.44% and effective specific enthalpy-drop of 0.145% are the best performance. By evaluating the steam turbine economic, however, static-pressure recovery coefficient and specific enthalpy drop are 1.25 times and 0.475 times of that without pipelines, respectively, relative to built-in pipelines. Therefore, a recommendation on the consideration of twin exhaust passage, last stage blades, steam extraction pipelines, low-pressure heater, and wet steam can obtain a representative aerodynamic characteristic.

Axial-Swept Influence on Inner Flow Performance of HP Steam Turbine Based on CFD

Swept blade technology was used to redesign the supercritical steam turbine sets that could improve the inner-efficiency of turbine sets and decrease the consumption of coal the noxious gas such as NOx. The eighth high-pressure stages, including static and rotor cascades, were selected as tested prototypes that were blew in the low-velocity wind tunnel. We used the five-hole ball head needle to measure the aerodynamic parameters distribution along the width and span direction of the high-pressure stage cascades. With the inkblot display technology, the limit flow spectrums were displaced in the blade surface and the endwalls. These tested data could be used to check the simulation results of CFD software. To improve the efficiency of the steam turbine high-pressure (HP) stage, we selected the supercritical steam turbine HP stage cascade blade as the prototype to research into its inner flow performance of the axial-swept blade by the CFD software. Two different redesigned blades, with ±20°, swept angle, and 30% swept height, named axial fore-swept and axial aft-swept, were built up. The stage passages flow field of the prototype blade, and the two redesigned swept blades were simulated using CFD software with stage interface planes between the stages. The CFD simulation results indicated that the leading edge of swept blades influenced the inlet flow field; the pressure in aft-swept blade stage in both endwalls was higher than in the middle and was beneficial to improve the passage flow properties of HP stage. But for the fore-swept HP stage, its pressure distribution was lower in both endwalls than in the middle and not beneficial to passage flow.

Fly ash from modern coal-fired power technologies: chloride ingress and carbonation of concrete

Low-lime fly ashes produced from modern coal-fired power technologies (developed to enhance efficiency/lower emissions), including nitrogen oxide (NOx) reduction, co-combustion, supercritical steam and oxy-fuel combustion, and their effects on chloride ingress and carbonation of concrete are investigated in this paper. Earlier work indicates that some of these technologies influence fly ash properties, but they mainly follow typical behaviour found for the material (consistence and compressive strength) in concrete. Both accelerated and normal-type exposure tests were carried out on a range of practical water/cement ratio concretes (also enabling interpolation for comparisons at equal 28 d strength). The test fly ash concretes were evaluated against (i) those containing three reference fly ashes covering a range of fineness and (ii) corresponding studies on fly ash concretes from the 1990s. The results show that there was an influence of fly ash fineness, reflected in reactivity/porosity (measured on mortar), and aspects of chemistry on chloride ingress, but there appeared to be minor material effects on carbonation. Comparison with the 1990s data indicated similar behaviour for the materials between studies for both properties. A relationship was also identified for the product of reactive alumina and sub-10 μm contents of the modern fly ashes and chloride resistance of concrete.

Methods for High-Purity Aluminum Oxide Production for Growth of Leucosapphire Crystals (Review)

Methods for the preparation of raw materials to produce leucosapphire are considered. It is shown that the main directions in the production of high-purity aluminum oxide raw materials are: electrochemical oxidation of aluminum, decomposition of alkoxides, high-temperature treatment of aluminum oxide in a halogen-containing atmosphere, and preliminary purification of aluminum-containing compounds followed by their decomposition. It is shown that methods of the purification of aluminum hydroxide and oxide obtained by the Bayer process are the most promising for industrial use. These methods include the complex purification and simultaneous preparation of ceramic preforms starting from aluminum hydroxides or oxides by their treatment in subcritical or supercritical steam and the following heat treatment in a halogen-containing medium.

Supercritical steam generator design and thermal analysis based on HTR-PM

The high temperature gas-cooled reactor pebble-bed module (HTR-PM) being built by the Institute of Nuclear and New Energy Technology of Tsinghua University in China is a typical Generation IV nuclear power system. The subcritical steam generators in HTR-PM can be replaced by the supercritical steam generators to work with the current reactors and a supercritical steam turbine to improve the thermal efficiency, which is being presented in the third technical phase of the HTR-PM program in China. The supercritical high temperature gas-cooled reactor pebble-bed module system scheme is proposed based on HTR-PM. A supercritical steam generator with helically coiled tubes is designed. Parameters of the geometry and the design conditions are listed in detail. The heat transfer performance of the supercritical steam generator is analyzed, and the heat flux, the temperature variation and the heat transfer coefficient along the tube are shown. The effects of the transverse and longitudinal pitches between the tubes in the supercritical steam generator are very important. The tube length, tube bundle height, and the deviation of the tube length in various layers are compared with various transverse and longitudinal pitches and the optimal relative transverse and longitudinal pitches are illustrated.

Influence of modern coal-fired power technologies on fly ash properties and its use in concrete

The work reported in this paper investigated the properties and use of fly ash (FA) produced from technologies developed to reduce the environmental impact and improve the efficiency of the coal-fired power generation process. These include nitrogen oxides (NOx) reduction, co-combustion, supercritical steam technology and oxy-fuel combustion. The nine FA samples examined from these technologies were characterised physically, chemically and in terms of their reactivity. Tests were also carried out to determine the consistence (slump) and compressive strength of FA concretes. Comparisons were made with a selection of reference FAs, the requirements of BS EN 450-1 and reported FA studies from the 1980s and 1990s. The results indicated that, for some technologies, the FA tended to be coarser and of higher loss on ignition (co-combustion and in-combustion NOx reduction) while, for others lower carbon contents were found (supercritical steam) or there was little obvious effect. FA chemistry was slightly affected in some cases, but mainly as expected for the coal being used. There was general agreement between water requirement and activity index with FA fineness for the materials tested. For the FA concretes, similar effects were noted in terms of the dosage of superplasticising admixture needed for a target slump and compressive strength. The behaviour of the materials from the new technologies was found to be similar to that reported in earlier studies on FA and suggests suitability for their use in concrete construction.

Generation IV supercritical water-cooled nuclear reactors: Realistic prospects and research program

Existing conditions make possible obtaining information that being discussed openly by wide scientific community could help outlining or even establishing the expediency of a particular area of present and future research. Use link http://www.sciencedirect.com to learn about the topics or areas that most attract researchers from different countries. The Generation IV International Forum (GIF-IV) established in January 2000 has set a goal to improve the new generation of nuclear technologies in the following areas: stability, safety and reliability, economic competitiveness, proliferation resistance and physical protection. The purpose of the present publication is to prepare a discussion of one of the directions of development of fourth-generation NPPs, the groundwork for which has already been laid in thermal power engineering in various countries. The number of papers published annually on this topic is the largest among other similar topics dedicated to nuclear power plants of the fourth generation. Judging from the operating experience of existing nuclear power plants using water as a coolant, it can be ascertained that the tendency of building water-cooled nuclear power plants will remain during the next 30 to 50 years. During the present stage the task in the development of alternative types of reactors will be limited to demonstration of their performance and acceptability for future power engineering and the society. The project of supercritical water-cooled reactor is based on the operating experience of VVER, PWR, BWR reactors (more than 14,000 reactor-years); many years of experience accumulated in operating fossil thermal power plants (more than 400 power units; 20,000 years of operation of power units) using supercritical (25 MPa, 540°C) and super-supercritical (35–37 MPa, 620–700°C) water steam. In Russia more than 140 supercritical pressure units are currently in operation. Numerical calculation and design of supercritical water-cooled reactor (similarly to BR-10 reactor) will allow not only training personnel for future development of this technology, but will also help revealing the most difficult points requiring experimental confirmation with application of independent test facilities, as well as formulating the plan of first priority experimental studies. Knowledge accumulated over the last 10 years in the world allows the following: further specifying the already developed concept; developing a plan of specific priority studies; compiling task order for designing small-power pilot VVER SKP-30 reactor (30 MW-th). The scope of problems that are to be solved to substantiate VVER-SCP reactor and commence designing an experimental reactor with thermal capacity of 30 MW is the same as that in developing any type of nuclear reactor: physics of the reactor core; material related matters (primarily concerned with the reactor pressure vessel, fuel, and fuel rod cladding); thermal hydraulics of rod bundles in the near- and supercritical areas; water chemistry at supercritical pressure; corrosion of materials, development of safety systems. Research must be carried out both in static conditions and under irradiation. The absence in Russia during the extended time period of approved program with allocation of appropriate funding and preservation of the existing status during the coming two or three years will lead to the situation when Russia will be hopelessly lagging behind in the development of SCWR technology.

On the prospect of introduction of plasma ignition in power boilers

One of the most important issues for modern domestic power industry is the creation and further widespread introduction of solid propellant energy units for super-critical steam parameters with high efficiency (43–46%) and improved environmental parameters. This will significantly reduce the use of natural gas.At the same time, one of the major drawbacks of the operation of pulverized coal power units is the need to use a significant amount of fuel oil during start-up and shutdown of boilers to stabilize the burning of the coal torch in the variable boiler operating modes.In this regard, solid fuel TPPs need to be provided with fuel oil facilities, with all the associated problems to ensure the performance (heating of fuel oil in winter), reliability and safety. All of the above problems increase both the TPP capital construction costs, and the electricity generating cost.A practical solution to the above problems at present is the use of a plasma technology for coal torch ignition based on thermochemical preparation of fuel for combustion. The materials of the developments of JSC “NPO CKTI” on application of plasmatrons in boilers of thermal power plants at metallurgical complexes of the Russian Federation are also considered.Plasma ignition systems for solid fuels in boilers were developed by Russian specialists and were introduced at a number of coal-fi red power plants in the Russian Federation, Mongolia, North Korea, and Kazakhstan. Plasma ignition of solid fuels is widely used in China for almost 30% of power boilers.The introduction of plasma-energy technologies will improve the energy efficiency of domestic solid-fuel thermal power plants and can be widely implemented in the modernization of boilers.During the construction of new TPPs, the construction of fuel oil facilities can be abandoned altogether, which will reduce the capital costs of the construction of thermal power plants, reduce the construction footprint, and increase the TPP safety.