A Study of Sulfur Reactions in Furnace Deposits

1961 ◽  
Vol 83 (4) ◽  
pp. 444-449 ◽  
Author(s):  
M. Weintraub ◽  
S. Goldberg ◽  
A. A. Orning
Keyword(s):  
Fly Ash ◽  
Liquid Phase ◽  
Flue Gas ◽  
Coal Ash ◽  
Metal Corrosion ◽  
Maximum Absorption ◽  
Boiler Tube ◽  
External Tube ◽  
Sodium And Potassium ◽  
Tube Metal

A study was made of absorption of sulfur from synthetic flue gas by coal ash. When fly ash was placed in a temperature gradient like that in a deposit on a boiler tube, maximum absorption was found in the coldest layer. When held at constant temperature, maximum absorption was found at 1100 F. The amount of absorption was highest for fly ash from furnaces in which serious deposit formation was observed. It was also highest for fly ash containing the highest content of sodium and potassium. The sulfur is probably absorbed as mixtures of normal sulfates, pyrosulfates, and such compounds as potassium-ferric trisulfate. A liquid phase of these compounds in contact with tube metal causes corrosion. The maximum sulfur absorption found at 1100 F coincides with a maximum at the same temperature that has been observed for external tube-metal corrosion.

Corrosion of Superheaters and Reheaters of Pulverized-Coal-Fired Boilers, II

1961 ◽  
Vol 83 (4) ◽  
pp. 468-474 ◽  
Author(s):  
Carl Cain ◽  
Wharton Nelson
Keyword(s):  
High Temperature ◽  
Liquid Phase ◽  
Gas Phase ◽  
Coal Ash ◽  
Pulverized Coal ◽  
Corrosion Mechanism ◽  
Fireside Corrosion ◽  
Factors Affecting ◽  
Ferritic Alloys ◽  
Tube Metal

This paper deals with studies of high-temperature fireside corrosion of reheater and superheater tubes in pulverized-coal-fired boilers. Factors affecting the temperature range and rate of corrosion by molten complex alkali sulfates are described. The influence of sulfides, produced by reaction of complex sulfates with tube metal, on corrosion rate is discussed. The similarity of coal-ash to oil-ash corrosion mechanism is brought out. Methods for distinguishing liquid phase from gas-phase corrosion on ferritic alloys are presented.

Data-driven modeling of fireside corrosion rate

2017 ◽  
Vol 64 (4) ◽  
pp. 397-404 ◽  
Author(s):  
Amrita Kumari ◽  
S.K. Das ◽  
P.K. Srivastava
Keyword(s):  
Fly Ash ◽  
Corrosion Rate ◽  
Flue Gas ◽  
Thermal Power ◽  
Coal Ash ◽  
Gas Temperature ◽  
Ann Model ◽  
Fireside Corrosion ◽  
Content Type ◽  
Network Training

Purpose This paper aims to propose an efficient artificial neural network (ANN) model using multi-layer perceptron philosophy to predict the fireside corrosion rate of superheater tubes in coal fire boiler assembly using operational data of an Indian typical thermal power plant. Design/methodology/approach An efficient gradient-based network training algorithm has been used to minimize the network training errors. The input parameters comprise of coal chemistry, namely, coal ash and sulfur contents, flue gas temperature, SOX concentrations in flue gas, fly ash chemistry (Wt.% Na2O and K2O). Findings Effects of coal ash and sulfur contents, Wt.% of Na2O and K2O in fly ash and operating variables such as flue gas temperature and percentage excess air intake for coal combustion on the fireside corrosion behavior of superheater boiler tubes have been computationally investigated and parametric sensitivity analysis has been undertaken. Originality/value Quite good agreement between ANN model predictions and the measured values of fireside corrosion rate has been observed which is corroborated by the regression fit between these values.

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.

Application of Disk Aerators to Recarbonation of Alkaline Wastewater from Wet Gasification of Carbide

1991 ◽  
Vol 24 (7) ◽  
pp. 277-284 ◽  
Author(s):  
E. Gomólka ◽  
B. Gomólka
Keyword(s):  
Carbon Dioxide ◽  
Liquid Phase ◽  
Gas Phase ◽  
Flue Gas ◽  
Carbonic Acid ◽  
Low Cost ◽  
Flue Gases ◽  
Carbon Dioxide Content ◽  
Patent Claim ◽  
Phase Dispersion

Whenever possible, neutralization of alkaline wastewater should involve low-cost acid. It is conventional to make use of carbonic acid produced via the reaction of carbon dioxide (contained in flue gases) with water according to the following equation: Carbon dioxide content in the flue gas stream varies from 10% to 15%. The flue gas stream may either be passed to the wastewater contained in the recarbonizers, or. enter the scrubbers (which are continually sprayed with wastewater) from the bottom in oountercurrent. The reactors, in which recarbonation occurs, have the ability to expand the contact surface between gaseous and liquid phase. This can be achieved by gas phase dispersion in the liquid phase (bubbling), by liquid phase dispersion in the gas phase (spraying), or by bubbling and spraying, and mixing. These concurrent operations are carried out during motion of the disk aerator (which is a patent claim). The authors describe the functioning of the disk aerator, the composition of the wastewater produced during wet gasification of carbide, the chemistry of recarbonation and decarbonation, and the concept of applying the disk aerator so as to make the wastewater fit for reuse (after suitable neutralization) as feeding water in acetylene generators.

scholarly journals Reactivity of Ground Coal Bottom Ash to Be Used in Portland Cement

J ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 223-232
Author(s):  
Esperanza Menéndez ◽  
Cristina Argiz ◽  
Miguel Ángel Sanjuán
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Bottom Ash ◽  
Blended Cement ◽  
Coal Ash ◽  
Pozzolanic Reaction ◽  
Natural Sand ◽  
Coal Bottom Ash ◽  
Novel Material ◽  
Pozzolanic Properties

Ground coal bottom ash is considered a novel material when used in common cement production as a blended cement. This new application must be evaluated by means of the study of its pozzolanic properties. Coal bottom ash, in some countries, is being used as a replacement for natural sand, but in some others, it is disposed of in a landfill, leading thus to environmental problems. The pozzolanic properties of ground coal bottom ash and coal fly ash cements were investigated in order to assess their pozzolanic performance. Proportions of coal fly ash and ground coal bottom ash in the mixes were 100:0, 90:10, 80:20, 50:50, 0:100. Next, multicomponent cements were formulated using 10%, 25% or 35% of ashes. In general, the pozzolanic performance of the ground coal bottom ash is quite similar to that of the coal fly ash. As expected, the pozzolanic reaction of both of them proceeds slowly at early ages, but the reaction rate increases over time. Ground coal bottom ash is a promising novel material with pozzolanic properties which are comparable to that of coal fly ashes. Then, coal bottom ash subjected to an adequate mechanical grinding is suitable to be used to produce common coal-ash cements.

NOx process inhibition and energy efficiency improvement in new swirl modification device for steel slag based on coal combustion

2018 ◽  
Vol 16 (7) ◽  
Author(s):  
Junxiang Guo ◽  
Lingling Zhang ◽  
Daqiang Cang ◽  
Liying Qi ◽  
Wenbin Dai ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Flue Gas ◽  
Coal Combustion ◽  
Steel Slag ◽  
Coal Ash ◽  
Combustion Efficiency ◽  
Gas Temperature ◽  
Staged Combustion ◽  
Energy Efficiency Improvement ◽  
Swirl Combustion

Abstract In this study, a novel swirl combustion modified device for steel slag was designed and enhanced with the objective of achieving highly efficient and clean coal combustion and also for achieving the whole elements utilization of coal. Coal ash and steel slag were melted in the combustion chamber and subsequently entered the slag chamber. The detrimental substances solidified and formed crystals, which allowed for the comprehensive utilization of the ash and slag. Our experiments mainly aimed to mitigate the formation of NOx, while using the heat and slag simultaneously during the coal combustion without a combustion efficiency penalty. The increase in the device’s energy efficiency and reduction in the NOx emissions are important requirements for industrialization. The experiments were carried out in an optimized swirling combustion device, which had a different structure and various coal feeding conditions in comparison to previously reported devices. The fuel-staged and non-staged combustion experiments were compared under different coal ratios (bitumite:anthracite). For the fuel-staged combustion experiments, the NOx concentration in the flue gas was observed to decrease significantly when the coal ratio of 1:1, an excess air coefficient of 1.2, and a fuel-staged ratio of 15:85 were used. Under these conditions, the flue gas temperature was as high as 1,620°C, while the NOx concentration was as low as 320 mg/m3 at 6 % O2. The air-surrounding-fuel structure that formed in the furnace was very beneficial in reducing the formation of NOx. In comparison to other types of coal burners, the experimental combustion device designed in this study achieved a significant reduction of NOx emissions (approximately 80 %).

scholarly journals Production of ceramics from coal fly ash

2012 ◽  
Vol 18 (2) ◽  
pp. 245-254 ◽  
Author(s):  
Biljana Angjusheva ◽  
Emilija Fidancevska ◽  
Vojo Jovanov
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Solid State ◽  
Liquid Phase ◽  
Bending Strength ◽  
Coal Fly Ash ◽  
Liquid Phase Sintering ◽  
Heating Rates ◽  
Republic Of Macedonia ◽  
The Subject

Dense ceramics are produced from fly ash from REK Bitola, Republic of Macedonia. Four types of fly ash from electro filters and one from the collected zone with particles < 0.063 mm were the subject of this research. Consolidation was achieved by pressing (P= 133 MPa) and sintering (950, 1000, 1050 and 11000C and heating rates of 3 and 100/min). Densification was realized by liquid phase sintering and solid state reaction where diopside [Ca(Mg,Al)(Si,Al)2O6] was formed. Ceramics with optimal properties (porosity 2.96?0.5%, bending strength - 47.01?2 MPa, compressive strength - 170 ?5 MPa) was produced at 1100?C using the heating rate of 10?C/min.

Microstructure and Mechanical Properties of Ambiently-Cured Blended Coal Ash-Based Geopolymer Concrete

2016 ◽  
Vol 857 ◽  
pp. 400-404
Author(s):  
Tian Yu Xie ◽  
Togay Ozbakkaloglu
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Compressive Strength ◽  
Fly Ash ◽  
Bottom Ash ◽  
Coal Ash ◽  
Geopolymer Concrete ◽  
Mass Ratio ◽  
Blended Coal ◽  
Microstructure And Mechanical Properties

This paper presents the results of an experimental study on the behavior of fly ash-, bottom ash-, and blended fly and bottom ash-based geopolymer concrete (GPC) cured at ambient temperature. Four bathes of GPC were manufactured to investigate the influence of the fly ash-to-bottom ash mass ratio on the microstructure, compressive strength and elastic modulus of GPC. All the results indicate that the mass ratio of fly ash-to-bottom ash significantly affects the microstructure and mechanical properties of GPCs

Carbon capture and storage using coal fly ash with flue gas

2021 ◽  
Author(s):  
Tamilselvi Dananjayan Rushendra Revathy ◽  
Andimuthu Ramachandran ◽  
Kandasamy Palanivelu
Keyword(s):  
Fly Ash ◽  
Flue Gas ◽  
Carbon Capture ◽  
Coal Fly Ash ◽  
Carbon Capture And Storage ◽  
And Storage
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