Emission Characteristicsof of PCBs of Combustion of Sludge-Coal Water Slurry in Fluidized Bed

2013 ◽  
Vol 340 ◽  
pp. 382-387 ◽  
Author(s):  
Xiao Li Zhao ◽  
Wei Zhu

Sludge-coal water slurry (SCWS) can be produced by mixing coal water slurry (CWS) with sewage sludge according to differenct ratio. This paper focuses on the combustive feasibility of SCWS in a commercial circulating fluidized bed, and on the emission characteristics of polychlorinated biphenyls (PCBs) in flue gas fly ash and bottom ash during combustion of SCWS. The results indicated that incineration can do very well with the temperature 1000 degree, sludge coal water slurry (SCWS) can be effective in improving sludge incineration rate, if the proportion of sludge is 20%~30%,amounts of PCBs is relatively small in flue gas fly ash and bottom ash. So the best burning rate is 20%-30%. Although incineration flue gas fly ash and bottom ash emission standard don't have PCBs regulations, but since PCBs are toxic organic pollutants, it should be strictly regulated.

2013 ◽  
Vol 726-731 ◽  
pp. 1972-1976 ◽  
Author(s):  
Li Jun Nie ◽  
Yang Liu ◽  
Mei Huang

The coal-water slurry produced with Datong coal was tested in a home boiler for heating. The experiment results of dust collection with the new tube type electrostatic precipitation of fly ash of coal water slurry combustion fit the emission standard of air pollutants for boilers (GB 13271-2001). The parameters for the electrostatic precipitation are as follows: the drift velocity of fly ash of coal water slurry combustion, 10.39 cm/s, the number of the tube, 64, the size of the tube, 25.6cm×25.6cm×20cm, the power, 0.24kW.


2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 2689-2698
Author(s):  
Xuemin Liu ◽  
Songsong Zhang ◽  
Yongqiang Chang ◽  
Zhongwei Wang ◽  
Guoli Qi

The influence of main operating parameters on boiler performance was studied, such as bed pressure drop, primary air-flow and secondary air-flow. Combustion adjustment tests were carried out on a circulating fluidized bed boiler with rated capacity of 240 t/h. From the test results, it can be seen that the loss due to exit flue gas is the largest heat loss of the boiler, accounting for more than 70% of the total heat losses. For coal fired boilers, compared with the loss due to unburned solids, the loss due to unburned gases is quite small. The unburned carbon con-tent in bottom ash is far lower than the value in fly ash. The trend of CO concentration in the exit flue gas is similar to that of the unburned carbon content in fly ash. To achieve higher boiler efficiency, the bed pressure drop is suggested to be maintained in about 8.5-9.0 kPa and the oxygen content in exit flue gas around 4%. The NOx emission concentration usually presents a negative correlation with CO concentration in exit flue gas. Through combustion adjustment and operation optimization, the NOx emission can be decreased by about 30% without affecting the boiler efficiency.


2019 ◽  
Vol 7 (1) ◽  
pp. 73
Author(s):  
Yuanda Wattimena ◽  
Asri Gani ◽  
Medyan Riza

Adsorpsi emisi pembakaran batubara dengan menggunakan adsorben zeolit pada jenis briket dan pulverized telah dilakukan. Penelitian ini bertujuan untuk mengurangi emisi gas SO2 dan logam Hg yang berbahaya apabila rilis di udara bebas dengan cara menggunakan adsorben zeolit untuk kecendrungan emisi menjadi bottom ash yang lebih terkendali. Pengujian ini fokus mengevaluasi rasio optimal rasio adsorben terhadap jumlah batubara terhadap performa penyerapan, sehingga penggunaannya tidak mengurangi nilai bakar batubara. Prosedur pembakaran ekspremintal awal dimulai dari pencampuran batubara dan zeolit dengan rasio 4%, 6%, 8%, 10%  dan 12%  yang dibagi dalam bentuk briket dan pulverized. Kedua jenis sampel dibakar secara berurutan pada electrical stainless steel reaction tube furnace pada kondisi temperatur pembakaran Fludized Bed Coal Combustion yaitu 600oC, 700oC, dan 800oC dengan laju alir udara disesuaikan. Flue gas hasil pembakaran yang keluar dari outlet dianalisa menggunakan Gas Combustion and Emission Analyzer (E4400, E-Instrument). Logam Hg yang yang diserap oleh zeolit pada Bottom Ash dianalisa menggunakan NIC Mercury SP Anlayzer. Hasil pengujian menunjukan kinerja zeolit terhadap kapasitas penyerapan logam Hg untuk pembakaran batubara pulverized pada temperatur pembakaran  600oC, 700oC dan 800oC masing-masing didapat pada angka 33,6, 19,25 dan 9,97 ppb/gr serta pada pembakaran briket batubara  masing-masing didapat sebesar 59,83, 37,8 dan 24,22 ppb/gr. Secara simultan untuk mengurangi emisi SO2 dan logam berat Hg pada fly ash untuk temperatur pembakaran Fludized Bed Coal Combustion rasio optimum berkisar antara 6%-8% adsoben zeolit dari jumlah massa batubara Kaway XVI Kabupaten Aceh Barat. Kata kunci:adsorpsi,  fluidized bed combustion, zeolit, briket, pulverized


2018 ◽  
Vol 16 (1) ◽  
Author(s):  
Yuanda Wattimena

Penelitian ini bertujuan untuk mengurangi emisi gas SO2 dan logam Hg dengan menggunakan adsorben zeolit. Pengujian ini fokus mengevaluasi rasio optimal adsorben terhadap jumlah batubara dan performa penyerapan serta tidak mengurangi nilai bakar batubara. Ekspremintal awal dimulai dari pencampuran batubara dan zeolit dengan rasio 4%, 6%, 8%, 10% dan 12% yang dibagi dalam bentuk briket dan pulverized. Kedua jenis sampel dibakar secara berurutan pada electrical stainless steel reaction tube furnace pada temperatur pembakaran Fluidized Bed Combustion yaitu 600oC , 700oC dan 800oC dengan laju alir udara disesuaikan. Flue gas hasil pembakaran dianalisa menggunakan Gas Combustion and Emission Analyzer (E4400, E-Instrument). Logam Hg yang diserap oleh zeolit pada bottom ash dianalisa menggunakan NIC Mercury SP Anlayzer. Hasil pengujian menunjukan kinerja zeolit terhadap kapasitas penyerapan logam Hg untuk pembakaran batubara pulverized pada temperatur pembakaran 600oC, 700oC dan 800oC masing-masing didapat pada angka 33,6, 19,25 dan 9,97 ppb/gr serta pada pembakaran briket batubara masing-masing sebesar 59,83, 37,8 dan 24,22 ppb/gr. Secara simultan untuk mengurangi emisi SO2 dan logam berat Hg pada fly ash untuk temperatur pembakaran Fluidized Bed Combustion rasio optimum berkisar antara 6%-8% adsoben zeolit dari jumlah massa Batubara Kaway XVI Kabupaten Aceh Barat.


Author(s):  
Giuseppe Mininni ◽  
Dario Marani ◽  
Camilla Maria Braguglia ◽  
Ettore Guerriero ◽  
Andrea Sbrilli

The effects of combustion and feeding conditions on Polycyclic Aromatic Hydrocarbons (PAH) and PCDD/F formation and appearance in the emissions at the stack during sludge incineration are discussed in this paper. Partitioning in the solid streams of Cd, Cr, Cu, Mn, Ni, Pb and Zn is also analyzed. Tests were performed on a demonstrative plant equipped with a fluidized bed furnace (FBF) using sewage sludge either as is or spiked with chlorinated organic compounds (tetrachloroethylene or a mixture of tetrachloroethylene, chlorobenzene and toluene) to study the chlorine effect on the presence of micropollutants in the different streams. Exhaust gases were sampled both before and after the treatment system (bag house and wet scrubber). In the untreated flue gas the highest values of PCDD/F and PAH were detected when the afterburning chamber was not in use or operating at low temperatures. Operation of the afterburning chamber at temperature higher than 850–900 °C was sufficient to keep organic micropollutants concentrations in the untreated flue gas at reasonably low levels. No significant correlation of the operating conditions with emissions at the stack was found. High copper concentration in the feed enhanced PCDD/F formation, with exception of tests carried out with high afterburning temperature. The homologue profile of PCDD/F and PAH depended on test conditions. Preferential accumulation of heavy metals in the filter ash with respect to cyclone ash was quantified in terms of an enrichment factor. Out of the seven metals considered, only Cd and Pb undergo significant enrichment in the filter ash. The enrichment increased with increasing chlorine content of the feed. In contrast, Cu, Cr, Mn, Ni, and Zn behaved as refractory (non-volatile) elements even at high chlorine dosage. In accordance with the widely accepted hypothesis that metal enrichment is due to metal vaporization in the combustion chamber and subsequent condensation onto the filter ash particles, a thermodynamic model of the combustion process was able to satisfactorily predict the different metal behavior and the effect of chlorine dosage on metal enrichment.


Author(s):  
Yinghai Wu ◽  
Edward J. Anthony ◽  
Lufei Jia

The hydration of partially sulphated fluidized bed combustion (FBC) ash with saturated steam was carried out in the laboratory. The ash samples were obtained from a commercial-scale 165 MWe circulating fluidized bed combustor (CFBC) firing a petroleum coke and coal blend. Both bottom ash and fly ash were tested, and in addition the bottom ash was also separated into five size fractions and tested. These solid streams and the “as-received” fly ashes were hydrated by steam produced in a pressure bomb for different lengths of time at different saturated temperatures. Samples of the ashes were analyzed for free lime and calcium hydroxide content before and after the hydration process. Scanning electron microscopy (SEM) with an energy dispersive X-ray system (EDX) was employed to determine physical characteristics of the samples. X-ray diffractograms (XRD) were also used to determine the phase composition. These results show that after hydration treatment with saturated steam at elevated pressures, the unreacted CaO in the partially sulphated material can be quantitatively converted to Ca(OH)2. However, the free lime content is also observed to change throughout the hydration process, which indicates that the hydration of CaO is not the only reaction occurring in this system. It is also clear that for fines, i.e., fly ash and <75 μm size fraction bottom ash, the effectiveness of the hydration depends much more strongly on hydration time and temperature than for coarser ashes and it is also clear that the behaviour of each particle size fraction is different.


Sign in / Sign up

Export Citation Format

Share Document