Slagging and Fouling in Coal Fired Boilers - Bright Hub
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This paper applies digital image techniques to observe the slagging characteristics of blended coals in a pilot-scale furnace Collected deposit samples were analyzed by scanning electron microscopy linked with energy-dispersive X-ray analysis SEM-EDX X-ray diffraction XRD and X-ray Fluorescence XRF to acquire the microstructure chemical composition and mineralogy
Fig 1 50 MW coal-fired utility boiler with steam flow rate of 210·103 kg h T fe Tgs and Tge denote flue gas temperatures at the furnace exit after the superheaters and after the air heater respectively Furnace wall slagging The mass flow rate of live steam is determined in the on-line mode from mass and energy balance equations Fig 2
high slagging takes place and when the silica ratio is lower than 65 it may lead to severe slagging For the co-firing of biomass at relatively low levels the mixed ash is still predominantly an alumino-silicate system and the normal coal slagging assessment
A slag flow submodel has been developed to simulate the slag flow and phase transformation behaviors in coal gasifiers The volume of the fluid VOF model is used to capture the free surface of the slag flow and the continuum surface force CSF model is employed to calculate the surface tension between the gas phase and the liquid slag phase
Coal ash is mainly composed of a complex mixture of SiO 2 Al 2 O 3 and CaO with alkali metals alkaline earth metals and transition metal oxides and their compounds 13-16 Generally slagging situation can be predicted according to the ST of coal ash 17 then suitable combustion equipment is selected and the apparatus further determines the coal species having a suitable ST
Slagging Factor for bituminous ash Fe 23 O CaO MgO 0 6 0 6 to 2 0 2 0 to 2 6 2 6 T 250 Temperature EC w here 1400 1400 to 1245 1245 to 1120 1120 Iron Calcium ratio 0 3 or 3 0 0 3 to 3 0 Iron plus Calcium 10 Slagging Index EC where max HT is the highest value of the hemisphere ash fusion temperature under reducing or oxidising
Two types of Zhundong coal with different properties were used to study the universality of minerals on the inhibition of slagging and fouling of different-property Zhundong coal The aim of the study is to select one effective and low-cost mineral as slagging and fouling preventative in Zhundong coal gasification in larger scale FBs
Coal Blending Coal Blending Coal blending is a practice that has been undertaken by many power stations to provide a consistent feedstock of fuel for power generation or to meet different requirements such as solving transportation problems fuel cost reducing slagging and SOx emission 133134
Slagging and Fouling Indices Index Formula Slagging or Fouling Propensity Low Mediu m High Severe
From the calculation get 168 13 T h of coal And from Fuel Air ratio 1 11 671 get 168 13 Total air consumption need get 1962 24 T h Ash fusion Temperature Chemical Composition These are proposing to find how much slagging and fouling inside boiler Because of limitation information we get only coal type A B which has chemical
Coal fired boilers experience deposition and slagging depending upon the ash characteristics of ash in the coal being fired In many cases the operating parameters also play a major role The molten or partial melting pasty ash deposits in radiant heat transfer surface like boiler furnace is termed as slagging The sintered ash deposit in the convection region in boiler is called fouling
Cyclone Slagging Index This index provides information on the slag flow behavior in cyclones This index is based upon partitioning of ash in the cyclone based on size and association of coal minerals Standard partitioning criteria have been developed to provide the composition of the slag
Jun 19 2018· With the slagging index R S when the test coal ash mass ratio for C 1 C 2 is 1 1 comparable values can be obtained for a mixture of coal ashes with biomass B 1 ash additions in the ratio of C 1 C 2 B 1 —15 70 15 Fig 3b for which the amount of fuel directed to the co-mass ratio of raw dry fuels was 7 37 56 m m
The Development of a Slagging and Fouling Predictive Methodology for Large Scale Pulverised Boilers Fired with Coal Biomass Blends By Piotr Patryk PŁAZA M Sc Power and Mechanical Engineering M Sc Environmental Engineering A Thesis submitted to Cardiff University for the Degree of Doctor of Philosophy in Mechanical Engineering
The conventional predictive slagging indices namely Base to acid ratio Slagging factor R s Iron oxide to calcium oxide ratio Silica to alumina ratio Sodium content of coal ash Sodium to potassium ratio and Iron oxide a re done for the coal ash samples and are shown in Table 4
Oct 20 2010· A slag flow submodel has been developed to simulate the slag flow and phase transformation behaviors in coal gasifiers The volume of the fluid VOF model is used to capture the free surface of the slag flow and the continuum surface force CSF model is employed to calculate the surface tension between the gas phase and the liquid slag phase
comprehensive slagging index of mixed coal mixed coal prices According to the industrial analysis of coal ash comprehensive index R and coal prices according to the four coal blending program to calculate the coal price in accordance with the ratio of linear addition to calculate the indicators as shown in table 4 Table 4
Oct 01 2018· The combustion of pulverized coal in power stations is expected to continue to be used for electricity generation for many years to come In pulverized coal combustion slagging and ash deposition are a set of the serious operational problems associated with power station boilers
Slagging Fouling Calculator - Coal Shastra Read More calculation of blend ratio in coal - BINQ Mining · Coal Blending Calculation Method Docstoc Documents Jan 06 2011 · Coal Blending Calculation It is common practice in Brazil to blend Jellinbah coal at around 10-15 of the coke blend Read More Some factors
The impurities in coal are converted into molten slag typically containing SiO2 FeO CaO and Al2O3 when coal feedstock is burned in slagging gasifiers The slag flows down the gasifier sidewalls dissolves and penetrates and reacts with the refractory lining that protects the stainless steel shell of the gasifier from elevated temperatures
Ash is an impurity that will not burn The typical range of ash is 5 to 40 The Ash Increases handling costs affects combustion efficiency and boiler efficiency reduces handling and burning capacity and may causes clinkering and slagging 8 Moisture content Moisture in coal …
Oct 25 2006· With nearly 80 mln tonnes of coal due to be imported by the power sector the central regulator has developed a coal index to determine price The regulator has given a 60 weightage to the ACR Asian Index 30 weightage to Producer Price Index of Australia and 10 weightage to Barlow Jonker Index BJI
article{osti title = {Sintering and collapse of synthetic coal ash and slag cones as observed through constant heating rate optical dilatometry} author = {Hsieh Peter Y } abstractNote = {Ash agglomeration and slagging are responsible for costly maintenance problems in coal-fired boilers Boiler design and operation rely on critical ash fusion temperatures defined by geometric
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were used to calculate B A ratio 1 2 3 Slagging index analysis The slagging index R s of a coal has traditionally been taken as a measure of the slagging propensity of the ash Russell et al 2002 This value indicates the trend in slagging similar to B A ratio and was calculated from Eq 2 It is normally combined