The Study of Partitioning of Heavy Metals During Fluidized Bed Combustion of Sewage Sludge and Coal

2005 ◽  
Vol 128 (2) ◽  
pp. 104-110 ◽  
Author(s):  
I. Gulyurtlu ◽  
M. Helena Lopes ◽  
P. Abelha ◽  
I. Cabrita ◽  
J. F. Santos Oliveira
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Fluidized Bed ◽  
Bituminous Coal ◽  
Fluidized Bed Combustion ◽  
Sulphur Compounds ◽  
Legal Limits ◽  
Higher Temperature ◽  
Combustion Tests ◽  
Fluidized Bed Combustor

The behavior of Cd, Cr, Cu, Co, Mn, Ni, Pb, Zn, and Hg during the combustion tests of a dry granular sewage sludge on a fluidized bed combustor pilot (FBC) of about 0.3 MW was evaluated. The emissions of these heavy metals from mono-combustion were compared with those of co-combustion of the sludge with a bituminous coal. The effect of the addition of limestone was also studied in order to retain sulphur compounds and to verify its influence on the retention of heavy metals (HM). Heavy metals were collected and analyzed from different locations of the installation, which included the stack, the two cyclones, and the material removed from the bed. The results showed that the volatility of metals was rather low, resulting in emissions below the legal limits of the new directive on incineration, with the exception of Hg during the mono-combustion tests. The partitioning of metals, except for Hg, appeared to follow that of ashes, amounting to levels above 90% in the bed streams in the mono-combustion case. For co-combustion, there was a lower fixation of HM in the bed ashes, mostly originating essentially from the sewage sludge, ranging between 40% and 80%. It is believed that in this latter case, a slightly higher temperature could have enhanced the volatilization, especially of Cd and Pb. However these metals were then retained in fly ashes captured in the cyclones. In the case of Hg, the volatilisation was complete. The bed ashes were free of Hg and part of Hg was retained in the cyclones and the rest was emitted either with fine ash particles or in gaseous forms. In mono-combustion the Hg emissions from the stack (particles and gas) accounted for about 50%, although there was a significant amount unaccounted for. This appeared to have significantly decreased in the case of co-combustion, as only about 15% has been emitted, due to the retention effect of cyclone ashes which presented high quantities of unburned matter, calcium and sulphur.

The Study of Partitioning of Heavy Metals During Fluidized Bed Combustion of Sewage Sludge and Coal

2003 ◽  
Author(s):  
I. Gulyurtlu ◽  
M. Helena Lopes ◽  
P. Abelha ◽  
I. Cabrita ◽  
J. F. Santos Oliveira
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Bituminous Coal ◽  
Unburned Carbon ◽  
Fluidized Bed Combustion ◽  
Sulphur Compounds ◽  
Legal Limits ◽  
Bed Temperature ◽  
Combustion Tests ◽  
Sulphur Species

The behaviour of Cd, Cr, Cu, Co, Mn, Ni, Pb, Zn and Hg during the combustion tests of granular dry sewage sludges on a pilot FBC of about 0,3 MW was evaluated. The emissions of these heavy metals from mono-combustion were compared with those of co-combustion of the sludge with a bituminous coal. The effect of the addition of limestone was also studied in order to retain sulphur compounds and to verify its influence on the retention of heavy metals. Heavy metals were collected and analysed from different locations of the installation, which included the stack, the two cyclones and the material removed from the bed. The results showed that the volatility of metals was rather low, resulting in emissions below the legal limits of the new directive on incineration, with the exception of Hg during the mono-combustion tests. The partitioning of metals, except for Hg, appeared to follow that of ashes, amounting to levels above 90% in the bed streams in the mono-combustion case. For co-combustion, there was a lower fixation of HM in the bed ashes, mostly originating essentially from the sewage sludge, ranging between 40 and 80%. It is believed that in this latter case, a slightly higher bed temperature could have enhanced the volatilisation, especially of Cd and Pb. However these metals were then retained in cyclone ashes. In the case of Hg, the volatilisation was complete. The bed ashes were free of Hg and part of it was retained in the cyclone and emitted as both fine ash particles and in gaseous forms. In mono-combustion the Hg emissions from the stack (particles and gas) accounted for about 50%, although there was a significant amount unaccounted for. This appeared to have significantly decreased in the case of co-combustion, as only about 15% has been emitted, due to the retention effect of cyclone ashes which presented high quantities of unburned carbon and possibly condensed sulphur species.

Experimental Studies on Combustion of Cattle Manure in a Fluidized Bed Combustor

1987 ◽  
Vol 109 (2) ◽  
pp. 49-57 ◽  
Author(s):  
K. Annamalai ◽  
M. Y. Ibrahim ◽  
J. M. Sweeten
Keyword(s):  
Fluidized Bed ◽  
Fossil Fuels ◽  
Experimental Studies ◽  
Heat Content ◽  
Fluidized Bed Combustion ◽  
Volatile Solids ◽  
Combustion Technology ◽  
Solids Content ◽  
Combustion Tests ◽  
Fluidized Bed Combustor

Manure from cattle feedlots is a renewable energy source which has the potential of supplementing the existing fossil fuels. But the heat content of manure is rather low. Since, the fluidized bed combustion technology has been used for the energy conversion of marginal fuels, such a technology is being explored for the combustion of feedlot manure. A fluidized bed combustor of 0.15 m (6 in.) diameter was used for the combustion tests on manure. Experiments were conducted with −20 to +20 percent excess air and at bed temperatures ranging from 600°C (1112°F) to 800°C (1472°F). Experimental data revealed that the gasification efficiencies ranged from 90 to 98 percent, while the combustion efficiencies varied from 45 to 85 percent. Higher combustion efficiencies were obtained with decreased volatile solids content of manure. The low combustion efficiencies are attributed to the limited residence time available for the volatiles to burn within the reactor.

scholarly journals N2O and NO Emissions from CFBC Cofiring Dried Sewage Sludge, Wet Sewage Sludge with Coal and PE

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Zhiwei Li ◽  
Hongzhou He
Keyword(s):  
Sewage Sludge ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Pilot Scale ◽  
Conversion Ratio ◽  
Fluidized Bed Combustion ◽  
Mixed Fuel ◽  
Higher Temperature ◽  
Circulating Fluidized Bed Combustion ◽  
No Emissions

Experiments on cofiring dried sewage sludge, wet sewage sludge with coal and polyethylene (PE) were carried out on a pilot scale 0.15MWt circulating fluidized bed combustion (CFBC) plant, and the influence of furnace temperatures, cofiring rates on N2O and NO emissions was investigated. Temperature is an effective parameter influencing N2O emission, and higher temperature leads to significant N2O reduction and decrease of conversion ratio of fuel-N to N2O. Increasing in cofiring rates leads to higher nitrogen content in the mixed fuel, which could result in higher NO and N2O emissions from combustion. With more sewage sludge addition, higher NO but lower N2O emissions are observed. N2O emission from cofiring wet sewage sludge with coal is higher than that from cofiring dried sewage sludge with coal and PE, and fuel-N conversion ratio to N2O and NO is much higher in cofiring wet sewage sludge with coal than that in cofiring dried sewage sludge with coal and PE.

Emission Characteristics of Heavy Metals and Organic Pollutants from the Combustion of Sewage Sludge in a Fluidized Bed Combustor

2008 ◽  
Vol 22 (4) ◽  
pp. 2278-2283 ◽  
Author(s):  
Jingai Shao ◽  
Rong Yan ◽  
Hanping Chen ◽  
Haiping Yang ◽  
Dong Ho Lee ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Fluidized Bed ◽  
Organic Pollutants ◽  
Emission Characteristics ◽  
Fluidized Bed Combustor

Sulphur Oxidation States in Residues from a Small-Scale Circulating Fluidized Bed Combustor

1988 ◽  
Vol 136 ◽  
Author(s):  
E. E. Berry ◽  
R. T. Hemmings ◽  
B. J. Cornelius ◽  
E. J. Anthony
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Small Scale ◽  
Fluidized Bed Combustion ◽  
Sulphur Compounds ◽  
Combustion Gas ◽  
Gas Cleaning ◽  
Utility Scale ◽  
Fluidized Bed Combustor ◽  
Circulating Fluidized Bed Combustion

ABSTRACTSignificant concentrations (∼6%, as CaS) of sulphides or other reduced-sulphur species in solid residues from a small-scale circulating fluidized bed (CFB) combustor have been reported in the literature. The presence of sulphides in similar quantities in residues from a utility-scale combustor would present significant difficulties with handling, disposal or utilization of the residues. This paper discusses the preliminary findings of an investigation of sulphur capture in a small-scale circulating fluidized bed combustion (CFBC) unit using a limestone bed and burning a high-S, high-Fe, Eastern Canadian coal. Data are presented on sulphur capture and chemical speciation for residue samples taken from a number of locations in the circulating bed during operation. The results are discussed in terms of probable mechanisms for the formation of sulphur compounds of reduced oxidation state in the bed and the combustion-gas cleaning system.

Behaviour of inorganic constituents of municipal sewage sludge during fluidized-bed combustion

2007 ◽  
Vol 61 (3) ◽  
Author(s):  
M. Hartman ◽  
M. Pohořelý ◽  
O. Trnka
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Fluidized Bed ◽  
Fluidized Bed Reactor ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Fluidized Bed Combustion ◽  
Metal Contents ◽  
Inorganic Constituents

AbstractThe fate of main heavy metals in municipal sewage sludge (As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, and Zn) was investigated using a fluidized-bed reactor. The behaviour of metals in the incinerator was explored by comparing metal contents in the two main ash streams: bottom (in-bed) ash and ash separated by a cyclone (cyclone-catch ash). All metals showed enrichment in the cyclone ash. The ash originating from sewage sludge is thermally quite stable consisting of quartz, hematite, spar(s), mica(s), apatite, and anhydrite. It does not soften nor becomes sticky and does not tend to agglomerate at temperatures up to 950°C.

scholarly journals Highly Effective Adsorption Process of Ni(II) Ions with the Use of Sewage Sludge Fly Ash Generated by Circulating Fluidized Bed Combustion (CFBC) Technology

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3106
Author(s):  
Tomasz Kalak ◽  
Kinga Marciszewicz ◽  
Joanna Piepiórka-Stepuk
Keyword(s):  
Fly Ash ◽  
Sewage Sludge ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Fluidized Bed Combustion ◽  
Nickel Ions ◽  
Suitable Material ◽  
Circulating Fluidized Bed Combustion

Recently, more and more attention has been paid to the removal of nickel ions due to their negative effects on the environment and human health. In this research, fly ash obtained as a result of incineration of municipal sewage sludge with the use of circulating fluidized bed combustion (CFBC) technology was used to analyze the possibility of removing Ni(II) ions in adsorption processes. The properties of the material were determined using analytical methods, such as SEM-EDS, XRD, BET, BJH, thermogravimetry, zeta potential, SEM, and FT-IR. Several factors were analyzed, such as adsorbent dose, initial pH, initial concentration, and contact time. As a result of the conducted research, the maximum sorption efficiency was obtained at the level of 99.9%. The kinetics analysis and isotherms showed that the pseudo-second order equation model and the Freundlich isotherm model best suited this process. In conclusion, sewage sludge fly ash may be a suitable material for the effective removal of nickel from wastewater and the improvement of water quality. This research is in line with current trends in the concepts of circular economy and sustainable development.

A Simulation Study for Fluidized Bed Combustion of Petroleum Coke With CO2 Capture

2003 ◽  
Author(s):  
Jinsheng Wang ◽  
Edward J. Anthony ◽  
J. Carlos Abanades
Keyword(s):  
Power Generation ◽  
Fluidized Bed ◽  
Petroleum Coke ◽  
Co2 Capture ◽  
Low Cost ◽  
Volatile Content ◽  
Fluidized Bed Combustion ◽  
High Carbon ◽  
Overall Efficiency ◽  
Fluidized Bed Combustor

Petroleum coke is regarded as a difficult fuel because of its high sulphur content and low volatile content. However, its low price and increased production, means that there is a powerful economic stimulus to use it for power generation. In this work, a process simulation has been performed as part of a feasibility study on the utilization of petroleum coke for power generation with low-cost CO2 capture. The proposed system employs a pressurized fluidized bed combustor and a calciner. In the combustor itself, the petroleum coke is burned and most of the CO2 generated is captured by a CaO sorbent under pressurized condition to form CaCO3. The CaCO3 is transported into the calciner where limited proportion of the petroleum coke is burned with pure O2, and calcines the spent sorbent back into CaO and CO2. A nearly pure CO2 stream is obtained from the calciner for subsequent disposal or utilization. The predicted overall efficiency of the combustion is near 40%. The proposed system would also be suitable for firing other high carbon and low ash fuel, such as anthracite.

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