STUDI EFISIENSI BOILER TERHADAP NILAI KALOR BATUBARA PADA BOILER JENIS PULVERIZER COAL KAPASITAS 300 T/H

2020 ◽  
Vol 3 (2) ◽  
pp. 122-130
Author(s):  
Wawan Gunawan ◽  
Bambang Ali Gunawan
Keyword(s):  
Flue Gas ◽  
Turbine Generator ◽  
Fuel Ratio ◽  
Excess Air ◽  
Heat Value

Boiler merupakan proses terjadinya pembakaran bahan bakar batubara pada bejana tertutup yang digunakan untuk menghasilkan steam. Steam tersebut dapat menggerakkan turbine-generator untuk menghasilkan listrik. Excess air merupakan persentase oksigen didalam fraksi massa yang terkandung didalam udara hasil pembakaran (flue gas). Nilai excess air dan efisiensi pada mesin boiler dapat diketahui dengan metode analisa deskriptif dan analisa perhitungan. Tujuan penelitian ini adalah untuk mengetahui pengaruh nilai kalor batubara terhadap nilai efisiensi dan pengaruh nilai kalor batubara terhadap excess air dengan menggunakan metode analisa deskriptif. Prosedur perhitungan diawali dengan menghitung entalpi aktual, low heat value, efisiensi aktual pada variasi nilai kalor batubara dan menghitung Air Fuel Ratio (AFR) aktual, Air Fuel Ratio (AFR) ideal, serta excess air pada mesin boiler. Hasil perhitungan menunjukkan penggunaan batubara dengan nilai LHV lebih besar menghasilkan nilai efisiensi boiler yang lebih tinggi. Penggunaan batubara dengan LHV 31.773 kJ/kg memberikan nilai efisiensi boiler mencapai 57 % dengan nilai excess air sebesar 63,6 %. Sehingga nilai kalor batubara yang lebih tinggi memerlukan excess air yang lebih rendah serta menghasilkan efisiensi yang lebih tinggi.

Numerical Simulation on Moisture Influence to MSW Combustion

2014 ◽  
Vol 1006-1007 ◽  
pp. 181-184
Author(s):  
Zhu Sen Yang ◽  
Xing Hua Liu ◽  
Shu Chen
Keyword(s):  
Numerical Simulation ◽  
Moisture Content ◽  
Flue Gas ◽  
Combustion Process ◽  
Average Temperature ◽  
Excess Air ◽  
Heat Value ◽  
Moisture Influence ◽  
Excess Air Coefficient ◽  
Combustible Gases

The combustion process of municipal solid waste (MSW) in a operating 750t/d grate furnace in Guangzhou was researched by means of numerical simulation. The influence of MSW moisture content on burning effect was discussed. The results show that: with the moisture content dropped from 50% to 30%, the heat value could be evaluated from 13.72% to 54.91% and the average temperature in the furnace could be promoted 90-248°C. However, the combustible gases and particle in the flue gas of outlet would take up a high proportion since lacking of oxygen would lead to an incomplete combustion. The excess air coefficient should be increased to 2.043~2.593 in order to ensure the flue gas residence time more than 2s and temperature in the furnace higher to 800°C.

Sulphur Neutralization by Lignite Ash: Pilot-Scale Combustion Experiments

1979 ◽  
Vol 101 (4) ◽  
pp. 615-619 ◽  
Author(s):  
T. D. Brown ◽  
G. K. Lee ◽  
H. A. Bambrough
Keyword(s):  
Nitric Oxide ◽  
Flue Gas ◽  
Solid Phase ◽  
Coal Ash ◽  
Pilot Scale ◽  
Controlled Experiments ◽  
Excess Air ◽  
Nitric Oxide Emissions ◽  
Carry Over ◽  
Lime Addition

A pilot-scale research boiler (750 kg steam/hr) has been used to study the degree of sulphur neutralization during combustion experiments with three lignites. A series of four closely controlled experiments showed that sulphur balances close to 100 percent could be achieved in the pilot-scale system burning Gascoyne lignite; in these experiments the sulphur retained in solid phase residues varied between 21 and 24 percent of the input sulphur. It was also demonstrated with Utility lignite that external recirculation of flue-gas was moderately effective in reducing nitric oxide emissions at the expense of major increased in the carry-over of unburnt carbon. However, sulphur dioxide neutralization by the coal-ash cations remained essentially unchanged as the recirculation ratio increased. Enhancement of sulphur neutralization by dry lime addition to Poplar River lignite was only found to be effective at addition rates above 1/2 percent lime by weight. The effectiveness of the lime was found to increase as the excess-air level increased.

Novel Gas Cleaning With Integrated Energy Recovery

2011 ◽  
Author(s):  
Bo Herrlander
Keyword(s):  
Flue Gas ◽  
Energy Recovery ◽  
High Energy ◽  
Waste To Energy ◽  
Electricity Production ◽  
Blow Down ◽  
Gas Cleaning ◽  
Heat Value ◽  
Wet Scrubber ◽  
Plant Emissions

High-energy recovery combined with low emissions to air and water was targeted when Jo¨nko¨ping Energi planned their new Waste to Energy plant at Torsvik in Sweden. The plant is compliant with the new EU Industry Directive and the Waste Frame Directive R-formula, which defines energy recovery levels for recycle of energy. In total about 160 000 tons of municipal (40%) and commercial waste (60%) is annually converted into usable energy. The average heat value is 11,7 MJ/kg. The energy produced is a combination of electricity (14 MWe) and heat (42–56 MWth, depending on electricity production). The heat is recovered both in a boiler and in a condenser. The flue gas condensing system is combined with a heat pump (10 MWth) to optimize the heat recovery rate. The plant is designed to fulfill the requirements set by the Swedish authorities, which are more stringent than the EU emission requirements. Some examples of the plant emissions to air guarantees: dust 5, HCl 5, SO2 20, HF1, Hg 0,03, Cd+Tl 0,05, other HM 0,5 all in mg/Nm3 and dioxin 0,05 ng/Nm3. The flue gas cleaning upstream of the condenser consists of a combination of a semi-dry system and a wet scrubber. The gas cleaning system operating range goes from 60 000 up to 127 000 Nm3/h depending on load and fuel heat value. The semi-dry system is carrying out the major part of the gas cleaning and is sufficient to comply with the air regulations. However, in order to minimize the treatment of the condensate from the condenser the wet scrubber is installed after the semi-dry system and upstream the condenser. The blow down from the scrubber is reused within the plant. Thus the polishing scrubber secures minimal treatment of the condensate to comply with the local stringent limits, particular chlorides, before release to the recipient lake Munksjo¨n. Emissions to water were 2010 nitrogen 1,7 mg/l, Cl <3,6 mg/l, As 0,66 μg/l, Cd <0,07 μg/l, Cr <6 μg/l, Cu 0,8 μg/l, Hg <0,4 μg/l, Ni <0,66 μg/l, Pb<1,2 μg/l, Tl<1,3 μg/l, Zn<7,2 μg/l and PCDD/PCDF 0,0088 ng/l. In the wet scrubber acid stage residual HCl and excess ammonia from the SNCR system are removed. The latter compound is important to capture in order to prevent eutrophication. The combination of a semidry and a wet system enables an optimization of the flue gas cleaning with regard to the different operating situations, taking into account seasonal demand variations as well as fuel alterations. The concept has demonstrated very low emissions combined with low consumption of lime. The possibility to optimize the flue gas cleaning performance is a prerequisite for minimal condensate treatment and optimal energy recovery. The paper will describe the system and the operating experiences.

Technical Analysis on Lignite Drying Technology with High Temperature Flue Gas

2013 ◽  
Vol 448-453 ◽  
pp. 1335-1342 ◽  
Author(s):  
Zhi Qiang Wen ◽  
Xian Ran Zhu
Keyword(s):  
High Temperature ◽  
Flue Gas ◽  
Material Balance ◽  
Inert Atmosphere ◽  
Inlet Temperature ◽  
Rotating Speed ◽  
Fine Grained ◽  
Heat Value ◽  
Lower Heat ◽  
Drying Technology

The procedure and system of drum drying technology are introduced for lignite drying and upgrading with high temperature flue gas. The total moisture and inherent moisture of lignite decrease significantly after being dried and the lower heat value (LHV) increases greatly, which means that the quality of lignite is improved obviously. Both the moisture and air dried volatile of the dried product coal decrease gradually when increasing the drum inlet temperature. However, only the moisture decreases and the volatile varies little when increasing the drum outlet temperature.The rotating speed of drum will make a few impact on the drying degree. Because the combustion load and the drying output will affect each other, it is recommended that the independent pulverized coal system is added. The key factors affecting the system material balance are the ratio of fine-grained powder and lower heat value. The appropriate ratio of fine-grained powder is suggested. The inert atmosphere feeding system which can control the oxygen content independently must be designed.

Combustion Properties of Norwegian Biomass: Wood Chips and Forest Residues

2011 ◽  
Vol 110-116 ◽  
pp. 4564-4568 ◽  
Author(s):  
Ehsan Houshfar ◽  
Judit Sandquist ◽  
Wilson Musinguzi ◽  
Roger A. Khalil ◽  
Michaël Becidan ◽  
...  
Keyword(s):  
Flue Gas ◽  
Particle Concentration ◽  
Stable Operation ◽  
Forest Residues ◽  
Fuel Blends ◽  
Operation Conditions ◽  
Excess Air ◽  
Combustion Properties ◽  
Fuel Reactor ◽  
Air Staging

Flue gas emissions and particle size distribution were investigated during combustion experiments of wood, forest residue and mixtures of these two. The combustion experiments were carried out in a grate fired multi-fuel reactor with and without air staging at stable operation conditions and constant temperature of 850 °C. The overall excess air ratio was held at 1.6, and the primary excess air ratio was 0.8 during air staged experiments. NOx emissions are reduced by air staging. Fly ash particle concentration of forest residues in the flue gas is lower than wood. Aerosols number increased in the staged experiments for fuel blends.

NOx Emissions From Industrial Boilers: Potential Control Methods

1974 ◽  
Vol 96 (1) ◽  
pp. 1-6 ◽  
Author(s):  
C. W. Siegmund ◽  
D. W. Turner
Keyword(s):  
Flue Gas ◽  
Two Stage ◽  
Potential Control ◽  
Excess Air ◽  
Stage Combustion ◽  
Utility Boilers ◽  
Industrial Boilers ◽  
Potential Methods ◽  
Further Development ◽  
Methods Of Control

Future regulations may limit emissions of NOx from industrial/commercial boilers as well as utility boilers. The potential methods of control for these boilers are the same as those for utility boilers—low excess air, flue gas recycle, and two stage combustion. Low excess air and flue gas recycle can control NOx from thermal fixation. Two stage combustion controls both thermal and fuel NOx. Further development work is needed to apply these combustion modification procedures to industrial/commercial boilers in which volumetric heat release rate is normally quite high.

scholarly journals Errors Associated With Excess Air Multipoint Measurement Systems

2015 ◽  
Vol 36 (4) ◽  
pp. 405-423 ◽  
Author(s):  
Charlene Ramsunkar ◽  
Chris van Tonder ◽  
Walter Schmitz
Keyword(s):  
Flue Gas ◽  
Single Point ◽  
Flow Simulation ◽  
Simulation Software ◽  
Sampling Errors ◽  
Power Station ◽  
Air Content ◽  
Power Stations ◽  
Excess Air ◽  
Duct Geometry

Abstract Boiler combustion air is generally controlled by the excess air content measured at the boiler economiser outlet using oxygen (O2) analysers. Due to duct geometry and dimensions, areas of high and low O2 concentrations in the flue gas duct occur, which poses a problem in obtaining a representative measurement of O2 in the flue gas stream. Multipoint systems as opposed to single point systems are more favourable to achieve representative readings. However, ash blockages and air leakages influence the accuracy of O2 measurement. The design of multipoint system varies across ESKOMs’ Power Stations. This research was aimed at evaluating the accuracy of the multipoint oxygen measurement system installed at Power Station A and to determine the systematic errors associated with different multipoint systems designs installed at Power Stations' A and B. Using flow simulation software, FloEFDTM and Flownex®, studies were conducted on two types of multipoint system designs This study established that significantly large errors, as high as 50%, were noted between the actual and measured flue gas O2. The design of the multipoint system extraction pipes also introduces significant errors, as high as 23%, in the O2 measured. The results indicated that the sampling errors introduced with Power Station A’s system can be significantly reduced by adopting the sampling pipe design installed at Power Station B.

scholarly journals Analysis of Gas Recirculation Influencing Factors of a Double Reheat 1000 MW Unit with the Reheat Steam Temperature under Control

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4253
Author(s):  
Meng Yue ◽  
Guoqian Ma ◽  
Yuetao Shi
Keyword(s):  
Flue Gas ◽  
Feed Water ◽  
Steam Temperature ◽  
Intermediate Point ◽  
Point Temperature ◽  
Excess Air ◽  
Low Load ◽  
Reheat Steam ◽  
Gas Recirculation ◽  
Feed Water Temperature

In this paper, the simulation software EBSILON is used to simulate the reheat units, and the reheat temperature control mode is deeply explored. In the benchmark system, the influence of different load intermediate point temperature on the flue gas recirculation (FGR) is analyzed. Then, the effects of load, coal quality, excess air factor, and feed water temperature on FGR are studied under the premise of intermediate point temperature as design value, and the cause for FGR change is analyzed by comparing the cutoff bypass flue (CBF) system. The results show that under any load, the FGR decreases with the increase of the intermediate point temperature, while under low load, the change of the intermediate point temperature has a greater impact on the FGR rate. When the intermediate point temperature remains constant, the FGR plunge has an increase of load at low load and is almost unchanged at high load; the FGR rate of coal with low calorific value and high moisture content is low and the coal with low volatile and high ash content has great influence on reheat steam temperature; and the excess air factor and feed water temperature are inversely proportional to the flue gas recirculation rate. In the CBF system, the change trend is similar to the reference system, but under the same working condition, the FGR rate is higher than the latter.

Retrofit of a 75T/H PC-Fired Boiler Into a Coal/Gas Co-Firing One

2011 ◽  
Author(s):  
Dazhui Wen ◽  
Donglin Chen ◽  
Huifang Xu
Keyword(s):  
Flue Gas ◽  
Gas Flow ◽  
Heating Surface ◽  
Coke Oven ◽  
Coke Oven Gas ◽  
Normal Range ◽  
Coal Gas ◽  
Cooling Tube ◽  
Heat Value ◽  
Slag Cooling

For full use of low heat value of coke oven gas and operation under conditions of coal, gas and coal/gas, a previously 75t/h PC-fired boiler was retrofitted: six gas burners with dual-passage were installed under the originally PC-fired burners and tangentially arranged with a larger combustion circle and declined axes; the pulverized coal fired burners were declined downward 8∼10° so as to control the flame center; the heating surface of slag cooling tube and economizer were extended. The operation and test after the retrofit showed that: the combustion was very stable and temperature of the superheated steam was between the normal range under all conditions of load and fuel; the maximum steam rate was 59t/h and temperature of the exhaust flue gas was lower than 160°C under gas condition while gas flow was at 26000 Nm3/h; the maximum steam rate was 81t/h and temperature of the exhaust flue gas was lower than 147°C under coal condition; the maximum steam rate was 77t/h and temperature of the exhaust flue gas was about 155°C under coal/gas condition.

Experimental Study on Combustion Characteristic of Biomass Micron Fuel

2017 ◽  
Author(s):  
Qi Zhang ◽  
Bo Xiao ◽  
Shiping Jin ◽  
Xun Wang ◽  
Xiaokang Liu ◽  
...  
Keyword(s):  
Particle Size ◽  
Combustion Temperature ◽  
Combustion Characteristic ◽  
Agriculture Waste ◽  
Fuel Feed ◽  
Fuel Ratio ◽  
Excess Air ◽  
Waste Energy ◽  
Excess Air Coefficient ◽  
Forestry Residues

This study developed a new kind of biomass fuel with biomass (forestry residues, agriculture waste, energy crops and so on) crushed below certain particle size (micron level, ≤250 μm) to form biomass powder, biomass-micron-fuel (BMF). And effects of excess air coefficient, air-fuel ratio, and particle size of BMF on the combustion temperature were studied through a self-designed lab-scale cyclone combustion system. Results showed that temperature increased first and then decreased with the increasing air flow rate and best excess air coefficient occurred in the region of 1.05–1.18. Similarly, combustion temperature also increased first and then decreased as the fuel feed rate increased and 225 g/m3–265 g/m3 air-fuel ratio would guarantee the effective combustion of BMF. The influence of particle size on the combustion temperature was also determined under five different combustion conditions and results demonstrated that the smaller the particle size is, the higher the temperature will be. (CSPE)

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