Co-Combustion of Municipal Sludge With Wood/Coal in CFB: Enrichment of Phosphorous and Cadmium in Ashes

2003 ◽  
Author(s):  
Lars-Erik A˚mand ◽  
Bo Leckner ◽  
Leif Hansson ◽  
Olof Norrlo¨w
Keyword(s):  
Trace Elements ◽  
Fly Ash ◽  
Operating Conditions ◽  
Fluidised Bed ◽  
Municipal Sludge ◽  
Bag Filter ◽  
Wood Pellets ◽  
Feed System ◽  
Cfb Boiler ◽  
Fuel Feed

Municipal sludge, originating from two wastewater treatment plants in Sweden, has been burned together with wood pellets or bituminous coal in a circulating fluidised bed (CFB) boiler equipped with a secondary cyclone and bag filter for fly ash removal. Such co-combustion is an alternative to mono-combustion of sludge. The sludge is burned in either mechanically dewatered or pre-dried form. The mechanically dewatered sludge was fed with a pump, but pre-dried sludge could be fed by the fuel feed system normally used for coal. Both types of sludge were burned with either wood-pellets or coal as main fuel under identical operating conditions, typical for a CFB boiler. The focus was on ash balances and on analysis of fuels and ashes to obtain concentrations of relevant species. The presence of phosphorous (P) is of special interest in relation to trace elements, such as mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn). For this reason a comparison has been made between these trace elements and phosphorous in the various ashes and the original sludge as well as other sources of phosphorous that could be used for agricultural purposes. The results show that sewage sludge and fly ash, after combustion of sludge, contain similar amounts of phosphorous as other phosphorous sources for agricultural use, but the levels of trace elements in relation to phosphorous (Hg, Cd, Pb, Cr, Cu) are higher than in animal manure and artificial fertilizer and higher than the present limits in Sweden.

scholarly journals Co-Combustion of Pulp- and Paper Sludge With Wood: Emissions of Nitrogen, Sulphur and Chlorine Compounds

2003 ◽  
Author(s):  
Lars-Erik A˚mand ◽  
Bo Leckner ◽  
Solvie Herstad Sva¨rd ◽  
Marianne Gyllenhammar ◽  
David Eskilsson ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Paper Industry ◽  
Pulp And Paper ◽  
Operating Conditions ◽  
Gaseous Emissions ◽  
Fluidised Bed ◽  
Wood Pellets ◽  
Feed System ◽  
Cfb Boiler ◽  
Fuel Feed

Sludge from wastewater treatment plants in five Swedish pulp and paper mills has been burned together with wood in a circulating fluidised bed (CFB) boiler. The sludge was either mechanically dewatered or pre-dried. The mechanically dewatered sludge had to be fed with a pump, but the pre-dried sludge could be fed by the fuel feed system normally used for coal, wood chips or wood pellets. In parallel to the combustion tests in the CFB boiler the sludges were also investigated as single fuels in a small laboratory FB. The Swedish pulp and paper industry produces three major fractions of sludge: pure fibre sludge, sludge produced by employing a precipitation species like ironaluminiumsulphate, and finally, sludge subjected to biological cleaning. The way of production of the sludge influences its content of, for example, nitrogen, sulphur and chlorine, but the composition of the sludge is also influenced by the pulp and paper process. The present measurements show that the concentrations of nitrogen, sulphur and chlorine in the sludge have a great impact on the corresponding gaseous emissions from combustion. Actions to prevent these emissions could be necessary, depending on the origin of the sludge and treatment process used. In the present project all sludges were burned with wood-pellets as the main fuel under identical operating conditions, typical for a CFB boiler. Wood pellets were chosen as a well defined, low-polluting fuel that makes comparison of emissions from the sludges clear. Co-combustion with wood-pellets has the advantage of enabling operation also with wet sludges that cannot be used as single fuels without pre-drying. No actions were taken to improve sulphur and chlorine retention, by for example adding limestone. From a combustion point of view the co-combustion works well with low levels of carbon monoxide present in the flue gas and no light hydrocarbons.

TEKNOLOGI PENANGANAN EMISI GAS DARI INSINERATOR SAMPAH KOTA

2019 ◽  
Vol 11 (2) ◽  
Author(s):  
Prasetiyadi Prasetiyadi ◽  
Wiharja Wiharja ◽  
Sri Wahyono
Keyword(s):  
Fly Ash ◽  
Pressure Drop ◽  
Spray Drying ◽  
Flue Gas ◽  
Bag Filter

Proses pembakaran sampah kota melalui insinerator akan menghasilkan uap panas yang bisa dimanfaatkan  untuk membangkitkan energi listrik, akan tetapi pada proses ini juga menghasilkan output berupa flue gas yang didominasi oleh partikel (fly ash) dan gas beracun seperti: HCl, SO2, NOx, HF, Hg, Cd dan Dioxin. Sebelum dibuang ke udara bebas, flue gas tersebut harus diolah agar memenuhi baku mutu lingkungan. Teknologi penanganan partikel dan gas polutan tersedia dan dapat dibuat dengan berbagai kapasitas. Untuk menangani flue gas dari insinerator sampah digunakan Quencher untuk menekan laju pembentukan kembali dioksin dan furan setelah proses pembakaran,  Spray Drying Absorption (SDA) untuk mengikat gas asam dan  logam berat serta bag filter untuk menangkap partikel. Selain itu digunakan ID Fan dan Cerobong Asap untuk pengatasi pressure drop yang terjadi akibat pengoperasian peralatan APC dan melepas ke udara.

"Recent Patents on the Triboelectrostatic Separation of Fly Ash"

2019 ◽  
Vol 13 ◽  
Author(s):  
Haisheng Li ◽  
Wenping Wang ◽  
Yinghua Chen ◽  
Xinxi Zhang ◽  
Chaoyong Li
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
High Efficiency ◽  
Separation Efficiency ◽  
High Reliability ◽  
Operating Conditions ◽  
Security Requirements ◽  
Unburned Carbon ◽  
Efficient Operation ◽  
Triboelectrostatic Separation

Background: The fly ash produced by coal-fired power plants is an industrial waste. The environmental pollution problems caused by fly ash have been widely of public environmental concern. As a waste of recoverable resources, it can be used in the field of building materials, agricultural fertilizers, environmental materials, new materials, etc. Unburned carbon content in fly ash has an influence on the performance of resource reuse products. Therefore, it is the key to remove unburned carbon from fly ash. As a physical method, triboelectrostatic separation technology has been widely used because of obvious advantages, such as high-efficiency, simple process, high reliability, without water resources consumption and secondary pollution. Objective: The related patents of fly ash triboelectrostatic separation had been reviewed. The structural characteristics and working principle of these patents are analyzed in detail. The results can provide some meaningful references for the improvement of separation efficiency and optimal design. Methods: Based on the comparative analysis for the latest patents related to fly ash triboelectrostatic separation, the future development is presented. Results: The patents focused on the charging efficiency and separation efficiency. Studies show that remarkable improvements have been achieved for the fly ash triboelectrostatic separation. Some patents have been used in industrial production. Conclusion: According to the current technology status, the researches related to process optimization and anti-interference ability will be beneficial to overcome the influence of operating conditions and complex environment, and meet system security requirements. The intelligent control can not only ensure the process continuity and stability, but also realize the efficient operation and management automatically. Meanwhile, the researchers should pay more attention to the resource utilization of fly ash processed by triboelectrostatic separation.

Unsteady simulations of migration and deposition of fly-ash particles in the first-stage turbine of an aero-engine

2021 ◽  
pp. 1-21
Author(s):  
Z. Hao ◽  
X. Yang ◽  
Z. Feng
Keyword(s):  
Fly Ash ◽  
Film Cooling ◽  
Particle Deposition ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Velocity Model ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Aero Engine

Abstract Particulate deposits in aero-engine turbines change the profile of blades, increase the blade surface roughness and block internal cooling channels and film cooling holes, which generally leads to the degradation of aerodynamic and cooling performance. To reveal particle deposition effects in the turbine, unsteady simulations were performed by investigating the migration patterns and deposition characteristics of the particle contaminant in a one-stage, high-pressure turbine of an aero-engine. Two typical operating conditions of the aero-engine, i.e. high-temperature take-off and economic cruise, were discussed, and the effects of particle size on the migration and deposition of fly-ash particles were demonstrated. A critical velocity model was applied to predict particle deposition. Comparisons between the stator and rotor were made by presenting the concentration and trajectory of the particles and the resulting deposition patterns on the aerofoil surfaces. Results show that the migration and deposition of the particles in the stator passage is dominated by the flow characteristics of fluid and the property of particles. In the subsequential rotor passage, in addition to these factors, particles are also affected by the stator–rotor interaction and the interference between rotors. With higher inlet temperature and larger diameter of the particle, the quantity of deposits increases and the deposition is distributed mainly on the Pressure Side (PS) and the Leading Edge (LE) of the aerofoil.

scholarly journals Recovery of Cenospheres and Fine Fraction from Coal Fly Ash by a Novel Dry Separation Method

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3576
Author(s):  
Jan Wrona ◽  
Witold Żukowski ◽  
Dariusz Bradło ◽  
Piotr Czupryński
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Fine Fraction ◽  
Free Fall ◽  
Raw Material ◽  
Fluidised Bed ◽  
Air Chamber ◽  
Pneumatic Separation ◽  
Bed Separation ◽  
Separation Product

Aluminosilicate microspheres are a valuable fraction of coal fly ash with diverse applications due to their low density. Currently, there is no efficient and ecologically rational method of cenosphere recovery from fly ash. A combination of dry methods for the recovery of both fine ash particles and aluminosilicate microspheres from coal fly ash is presented. It is comprised of fluidised bed separation followed by screening and pneumatic separation in a free-fall air chamber. Fluidised bed separation was assisted by a mechanical activator to prevent agglomeration. This step reduced the portion of material that required further treatment by 52–55 wt.%, with the recovery of microspheres exceeding 97%. Then, the concentrates were individually subjected to pneumatic separation. The final separation product for the fly ash containing 0.64 wt.% cenospheres was a cenosphere concentrate that constituted about 17 wt.% of the initial fly ash. The recovery of cenospheres was around 81%. Usage of a combination of dry methods allowed for maintaining almost 83 wt.% of the raw material in its dry form. Furthermore, the produced fly ash grain fractions could be used for different industrial purposes.

Evaluation of the environmental and plant growth effectiveness of a new substrate consisting of municipal sludge and fly ash

2019 ◽  
Vol 99 ◽  
pp. 163-171 ◽  
Author(s):  
Bo Ma ◽  
Lijuan Liu ◽  
Yazhou Zhao ◽  
Chengliang Zhang ◽  
Zenghui Hu ◽  
...  
Keyword(s):  
Fly Ash ◽  
Plant Growth ◽  
Municipal Sludge

Monitoring of Fluctuations in the Physical and Chemical Properties of a High-Calcium Fly Ash

1987 ◽  
Vol 113 ◽  
Author(s):  
Scott Schlorholtz ◽  
Ken Bergeson ◽  
Turgut Demirel
Keyword(s):  
Fly Ash ◽  
Chemical Properties ◽  
Operating Conditions ◽  
Physical And Chemical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Morphological Studies ◽  
High Calcium ◽  
Physical And Chemical ◽  
And Chemical Properties

ABSTRACTThe physical and chemical properties of fly ash produced at Ottumwa Generating Station have been monitored since April, 1985. The fly ash is produced from burning a low sulfur, sub-bituminous coal obtained from the Powder River Basin near Gillette, Wyoming. One-hundred and sixty samples of fly ash were obtained during the two year period. All of the samples were subjected to physical testing as specified by ASTM C 311. About one-hundred of the samples were also subjected to a series of tests designed to monitor the self-cementing properties of the fly ash. Many of the fly ash samples were subjected to x-ray diffraction and fluorescence analysis to define the mineralogical and chemical composition of the bulk fly ash as a function of sampling date. Hydration products in selected hardened fly ash pastes, were studied by x-ray diffraction and scanning electron microscopy. The studies indicated that power plant operating conditions influenced the compressive strength of the fly ash paste specimens. Mineralogical and morphological studies of the fly ash pastes indicated that stratlingite formation occurred in the highstrength specimens, while ettringite was the major hydration product evident in the low-strength specimens.

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