scholarly journals Pilot-Scale Experiences on a Plasma Ignition System for Pulverized Fuels

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4726
Author(s):  
Reyhane Youssefi ◽  
Jörg Maier ◽  
Günter Scheffknecht
Keyword(s):  
Particle Size ◽  
Moisture Content ◽  
Power Plants ◽  
Thermal Power ◽  
Cold Start ◽  
Pilot Scale ◽  
Fuel Quality ◽  
Ignition System ◽  
Plasma Ignition ◽  
Start Up

The need for flexible power generation is growing worldwide as the energy transition is altering the operational regimes of thermal power plants. Plasma ignition systems, as an alternative technology to the conventional start-up method with natural gas or oil firing, offer a cost- and energy-efficient start-up process in pulverized fuel power stations. The application of plasma ignition systems for cold start-ups using different qualities of pre-dried lignite is investigated in a pilot-scale combustion facility. A plasma integrated swirl burner is developed and validated using highly ignitable lignite dust. Eight pre-dried lignite qualities with a moisture content of up to 30% and a broad particle size distribution are investigated for this application to determine the applicability and limitations of the plasma ignition system with regard to the fuel quality. The performance of lignites for cold start-up in the plasma ignition system are categorized based on their ignition and combustion performance. All lignite qualities were ignited under the cold-start-up condition with a plasma power of 4 kW to 7 kW. Lignite qualities with a moisture content of up to 20% and a median particle size of below 450 μm form a self-sustained flame with short-time plasma-supported combustion, while flame blow-out is observed for lignites with lower qualities.

On the prospect of introduction of plasma ignition in power boilers

2019 ◽  
Vol 12 (1) ◽  
pp. 22-28
Author(s):  
V. Ye. Mikhailov ◽  
S. P. Kolpakov ◽  
L. A. Khomenok ◽  
N. S. Shestakov
Keyword(s):  
Russian Federation ◽  
Solid Fuel ◽  
Power Plants ◽  
Thermal Power ◽  
Fuel Oil ◽  
Solid Fuels ◽  
Thermal Power Plants ◽  
Plasma Ignition ◽  
The Russian Federation ◽  
Capital Construction

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.

scholarly journals Wood Chip Drying through the Using of a Mobile Rotary Dryer

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1590 ◽  
Author(s):  
Angelo Del Giudice ◽  
Andrea Acampora ◽  
Enrico Santangelo ◽  
Luigi Pari ◽  
Simone Bergonzoli ◽  
...  
Keyword(s):  
Moisture Content ◽  
Power Plants ◽  
Black Locust ◽  
Thermal Power ◽  
Initial Moisture Content ◽  
Wood Chip ◽  
Wood Chips ◽  
Cocurrent Flow ◽  
Drying Process ◽  
Rotary Dryer

Drying is a critical point for the exploitation of biomass for energy production. High moisture content negatively affects the efficiency of power generation in combustion and gasification systems. Different types of dryers are available however; it is known that rotary dryers have low cost of maintenance and consume 15% and 30% less in terms of specific energy. The study analyzed the drying process of woody residues using a new prototype of mobile rotary dryer cocurrent flow. Woodchip of poplar (Populus spp.), black locust (Robinia pseudoacacia L.), and grapevine (Vitis vinifera L.) pruning were dried in a rotary drier. The drying cycle lasted 8 h for poplar, 6 h for black locust, and 6 h for pruning of grapevine. The initial biomass had a moisture content of around 50% for the poplar and around 30% for grapevine and black locust. The study showed that some characteristics of the biomass (e.g., initial moisture content, particle size distribution, bulk density) influence the technical parameters (i.e., airflow temperature, rate, and speed) of the drying process and, hence, the energy demand. At the end of the drying process, 17% of water was removed for poplar wood chips and 31% for grapevine and black locust wood chips. To achieve this, result the three-biomass required 1.61 (poplar), 0.86 (grapevine), and 1.12 MJ kgdry solids−1 (black locust), with an efficiency of thermal drying (η) respectively of 37%, 12%, and 27%. In the future, the results obtained suggest an increase in the efficiency of the thermal insulation of the mobile dryer, and the application of the mobile dryer in a small farm, for the recovery of exhaust gases from thermal power plants.

Variability in Thermal Performance and Measured Heat Rate in Fossil-Fuelled Power Plants

1992 ◽  
Vol 206 (2) ◽  
pp. 109-123 ◽  
Author(s):  
F L Carvalho ◽  
F H D Conradie ◽  
H Kuerten ◽  
F J McDyer
Keyword(s):  
Thermal Performance ◽  
Power Plants ◽  
Performance Monitoring ◽  
Unit Commitment ◽  
Thermal Power ◽  
Heat Rate ◽  
Plant Performance ◽  
Plant Management ◽  
Fuel Quality ◽  
Stable Operating

The paper examines the variability of key parameters in the operation of ten thermal power plants in various commercial grid environments with a view to assessing the viability of ‘on-demand’ plant performance monitoring for heat rate declaration. The plants of various types are limited to coal- and oil-fired units in the capacity range of 305–690 MW generated output. The paper illustrates the influence of control system configuration on effective and flexible power plant management. The analysis of variability indicates that there is a reasonable probability of achieving adequately stable operating periods within the normal operating envelope of grid dispatch instructions when thermal performance monitoring and display can be undertaken with a high confidence level. The levels of variability in fuel quality, which were measured during nominally constant levels of fuel input and generated output, range from about +1 per cent for oil-fired plants to about ±5 per cent for coal-fired power plants. The implications of adopting on-line monitoring of unit heat rate as an input to the generation ordering and unit commitment process are potentially significant cost and energy conservation benefits for utilities having a high proportion of coal- and oil-fired generation.

Model-Based Analysis of the Start-Up Improvement of a CCPP due to Steam Turbine Warm-Keeping With Air

2019 ◽  
Author(s):  
Dennis Toebben ◽  
Tobias Burgard ◽  
Sebastian Berg ◽  
Manfred Wirsum ◽  
Liu Pei ◽  
...  
Keyword(s):  
Power Plant ◽  
Steam Turbine ◽  
Power Plants ◽  
Cold Start ◽  
Nox Emissions ◽  
Data Set ◽  
Water Steam ◽  
Hot Air ◽  
Start Up ◽  
Low Load

Abstract Combined cycle power plants (CCPP) have many advantages compared to other fossil power plants: high efficiency, flexible operation, compact design, high potential for combined heat and power (CHP) applications and fewer emissions. However, fuel costs are relatively high compared to coal. Nevertheless, major qualities such as high operation flexibility and low emissions distinctly increase in relevance in the future, due to rising power generation from renewable energy sources. An accelerated start-up procedure of CCPPs increases the flexibility and reduces the NOx-emissions, which are relatively high in gas turbine low load operation. Such low load operation is required during a cold start of a CCPP in order to heat up the steam turbine. Thus, a warm-keeping of the thermal-limiting steam turbine results in an accelerated start-up times as well as reduced NOx-emissions and lifetime consumption. This paper presents a theoretical analysis of the potential of steam turbine warm-keeping by means of hot air for a typical CCPP, located in China. In this method, the hot air passes through the steam turbine while the power plant is shut off which enables hot start conditions at any time. In order to investigate an improved start-up procedure, a physical based simplified model of the water-steam cycle is developed on the basis of an operation data set. This model is used to simulate an improved power plant start-up, in which the steam turbine remains hot after at least 120 hours outage. The results show a start-up time reduction of approximately two-thirds in comparison to a conventional cold start. Furthermore, the potential of steam turbine warm-keeping is discussed with regards to the power output, NOx-emissions, start-up costs and lifetime consumption.

scholarly journals Selection Ideal Coal Suppliers of Thermal Power Plants Using the Matter-Element Extension Model with Integrated Empowerment Method for Sustainability

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Zhongfu Tan ◽  
Liwei Ju ◽  
Xiaobao Yu ◽  
Huijuan Zhang ◽  
Chao Yu
Keyword(s):  
Evaluation System ◽  
Supplier Selection ◽  
Power Plants ◽  
Thermal Power ◽  
Fuel Quality ◽  
Extension Model ◽  
Development Capacity ◽  
Generation Cost ◽  
Promethee Method ◽  
The Ideal

In order to reduce thermal power generation cost and improve its market competitiveness, considering fuel quality, cost, creditworthiness, and sustainable development capacity factors, this paper established the evaluation system for coal supplier selection of thermal power and put forward the coal supplier selection strategies for thermal power based on integrated empowering and ideal matter-element extension models. On the one hand, the integrated empowering model can overcome the limitations of subjective and objective methods to determine weights, better balance subjective, and objective information. On the other hand, since the evaluation results of the traditional element extension model may fall into the same class and only get part of the order results, in order to overcome this shortcoming, the idealistic matter-element extension model is constructed. It selects the ideal positive and negative matter-elements classical field and uses the closeness degree to replace traditional maximum degree of membership criterion and calculates the positive or negative distance between the matter-element to be evaluated and the ideal matter-element; then it can get the full order results of the evaluation schemes. Simulated and compared with the TOPSIS method, Romania selection method, and PROMETHEE method, numerical example results show that the method put forward by this paper is effective and reliable.

THE LIFE ASSESSMENT OF STEAM TURBINE ROTORS FOR FOSSIL POWER PLANTS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4371-4376
Author(s):  
SUNGHO CHANG ◽  
GEEWOOK SONG ◽  
BUMSHIN KIM ◽  
JUNGSEB HYUN ◽  
JEONGSOO HA
Keyword(s):  
Power Plant ◽  
Steam Turbine ◽  
Rotational Speed ◽  
Power Plants ◽  
Thermal Power ◽  
Creep Damage ◽  
Life Assessment ◽  
Life Extension ◽  
Start Up ◽  
Operational Life

The operational mode of thermal power plants has been changed from base load to duty cycle. From the changeover, fossil power plants cannot avoid frequent thermal transient states, for example, start up and stop, which results in thermal fatigue damage at the heavy section components. The rotor is the highest capital cost component in a steam turbine and requires long outage for replacing with a new one. For an optimized power plant operational life, inspection management of the rotor is necessary. It is known in general that the start-up and shutdown operations greatly affect the steam turbine life. The start-up operational condition is especially severe because of the rapid temperature and rotational speed increase, which causes damage and reduction of life of the main components life of the steam turbine. The start-up stress of a rotor which is directly related to life is composed of thermal and rotational stresses. The thermal stress is due to the variation of steam flow temperature and rotational stress is due to the rotational speed of the turbine. In this paper, the analysis method for the start-up stress of a rotor is proposed, which considers simultaneously temperature and rotational speed transition, and includes a case study regarding a 500MW fossil power plant steam turbine rotor. Also, the method of quantitative damage estimation for fatigue-creep damage to operational conditions, is described. The method can be applied to find weak points for fatigue-creep damage. Using the method, total life consumption can be obtained, and can be also be used for determining future operational modes and life extension of old fossil power units.

The Analytical Research and Development of On-Line Monitoring Models of Thermal State for Turbine Rotor

2013 ◽  
Vol 744 ◽  
pp. 105-109
Author(s):  
Shi Liu ◽  
Heng Liang Zhang ◽  
Yan Zhou ◽  
Dan Mei Xie
Keyword(s):  
Power Plants ◽  
Thermal Stresses ◽  
Thermal State ◽  
Thermal Power ◽  
Turbine Rotor ◽  
Limiting Factors ◽  
Monitoring And Control ◽  
Start Up ◽  
Temperature Dependent Properties ◽  
And Control

Steam turbine units are required to start up and shut down as fast as possible to improve economy and load-response ability of the units under the qualification of safety. it is important to monitor and control thermal state in turbine during operation, especially during the process of start-up and shutdown. Thermal stresses in turbine rotor in thermal power plants are the limiting factors for rapid startup, shutdown or load change. In this paper the online calculation models of temperature and thermal stress for a two-dimensional axis-symmetric object are obtained after disposing of the nonlinear factor such as temperature-dependent properties by a transformation. The model gained can be used to analyze thermal states in thick-walled components, monitoring and control online.

Measurement of Steam Generator or Reactor Vessel Moisture Carryover Using a Non-Radioactive Chemical Tracer

2009 ◽  
Author(s):  
Robert Fournier ◽  
Michael Thibodeau ◽  
Charles T. French
Keyword(s):  
Moisture Content ◽  
Steam Generator ◽  
Power Plants ◽  
Power Level ◽  
Thermal Power ◽  
Reactor Vessel ◽  
Saturated Steam ◽  
Power Calculation ◽  
Pressurized Water ◽  
Chemical Tracer

All nuclear power plants are licensed to operate at a specific thermal power. Verification of this power level is done by measuring the change in the enthalpy of the feedwater times the mass flow of the feedwater through each steam generator for pressurized water reactor or through the reactor vessel for boiling water reactors. When performing this measurement, it is necessary to determine the enthalpy of the steam exiting each steam generator or the reactor vessel. Since the exit enthalpy of most units is saturated steam, the state of the steam must be defined in terms of the enthalpy of dry stream minus the fraction of moisture being carried over with the steam times the heat of vaporization. The quality of the steam can be measured using a throttling calorimeter, but a much more accurate means of measurement is with the use of a chemical tracer salt that is only carried over with the main steam by droplets of water. Thus, the fraction of moisture in the steam can be defined as the ratio of concentration of the tracer in the steam divided by concentration of the tracer in the riser of the generator or reactor vessel. If the moisture content of the steam is not measured, one must assume that it is zero, which is conservative, since it provides an upper limit for the thermal power calculation. However, from an operational standpoint, if moisture carryover is present but is not accounted for, the thermal power of the unit will be below its licensed power level causing a loss in electrical output due both a lower thermal power and a reduction in turbine cycle efficiency. Moreover, if there is significant carryover, there is the potential for additional damage to the turbine blading and housing from the impingement of the water droplets. This paper describes how a chemical tracer can be used to measure the moisture content of the steam, considerations for the injection and sample points, plant alignment recommendations and the support required from a utility, when performing this test. The paper will also discuss the potential for long term degradation, the effects of extended power uprates on carryover and the limitations of chemistry guidelines.

Thermal Modeling of a Solar Steam Turbine With a Focus on Start-Up Time Reduction

2011 ◽  
Author(s):  
James Spelling ◽  
Markus Jo¨cker ◽  
Andrew Martin
Keyword(s):  
Steam Turbine ◽  
Power Plants ◽  
Thermal Power ◽  
The Body ◽  
Average Error ◽  
Steam Turbines ◽  
Effective Measure ◽  
Start Up ◽  
Turbine Casing ◽  
Main Steam

Steam turbines in solar thermal power plants experience a much greater number of starts than those operating in base-load plants. In order to preserve the lifetime of the turbine whilst still allowing fast starts, it is of great interest to find ways to maintain the turbine temperature during idle periods. A dynamic model of a solar steam turbine has been elaborated, simulating both the heat conduction within the body and the heat exchange with the gland steam, main steam and the environment, allowing prediction of the temperatures within the turbine during off-design operation and standby. The model has been validated against 96h of measured data from the Andasol 1 power plant, giving an average error of 1.2% for key temperature measurements. The validated model was then used to evaluate a number of modifications that can be made to maintain the turbine temperature during idle periods. Heat blankets were shown to be the most effective measure for keeping the turbine casing warm, whereas increasing the gland steam temperature was most effective in maintaining the temperature of the rotor. By applying a combination of these measures the dispatchability of the turbine can be improved significantly: electrical output can be increased by up to 9.5% after a long cool-down and up to 9.8% after a short cool-down.

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