scholarly journals Characteristics of refractory bricks used in the coke production kilns in Colombia

2021 ◽  
Vol 2046 (1) ◽  
pp. 012046
Author(s):  
J F Gelves ◽  
J Sánchez Zuñiga ◽  
J Sánchez Molina
Keyword(s):  
Coke Production ◽  
Refractory Bricks

Characterization of NORM Sources in Petroleum Coke Calcining Processes

2009 ◽  
Author(s):  
Ian S. Hamilton ◽  
Donald A. Halter ◽  
Donald F. Haumann ◽  
Erich H. Fruchtnicht ◽  
Matthew G. Arno
Keyword(s):  
Petroleum Coke ◽  
Product Life Cycle ◽  
Coke Production ◽  
Oil Refining ◽  
Refractory Materials ◽  
Energy Applications ◽  
Aerosol Generation ◽  
Feed Stock ◽  
Rotary Kilns ◽  
Refractory Bricks

Petroleum coke, or “petcoke,” is a waste by-product of the oil refining industry. The majority of petcoke consumption is in energy applications; catalyst coke is used as refinery fuel, anode coke for electricity conduction, and marketable coke for heating cement kilns. Roskill has predicted that long-term growth in petroleum coke production will be maintained, and may continue to increase slightly through 2012. Petcoke must first be calcined to drive off any undesirable petroleum by-products that would shorten the coke product-life cycle. As an example, the calcining process can take place in large, rotary kilns heated to maximum temperatures as high as approximately 1400–1540°C. The kilns and combustion/settling chambers, as well as some cooler units, are insulated with refractory bricks and other, interstitial materials, e.g., castable refractory materials, to improve the efficiency of the calcining process. The bricks are typically made of 70–85-percent bauxite, and are slowly worn away by the calcining process; bricks used to line the combustion chambers wear away, as well, but at a slower rate. It has been recognized that the refractory materials contain slight amounts of naturally occurring radioactive materials (NORM) from the uranium- and thorium-decay series. Similarly, low levels of NORM could be present in the petcoke feed stock given the nature of its origin. Neither the petcoke nor the refractory bricks represent appreciable sources of radiation or radioactive waste. However, some of the demolished bricks that have been removed from service because of the aforementioned wearing process have caused portal alarms to activate at municipal disposal facilities. This has lead to the current investigation into whether there is a NORM concentrating mechanism facilitated by the presence of the slightly radioactive feed stock in the presence of the slightly radioactive refractory materials, at calcining-zone temperatures. Research conducted to date has been used to determine the speciation and concentration of nuclides in both the feed stock and the various refractory materials, as well as the slag that forms at the interface of the two materials, as a function of temperature. Further investigation into any potential for generation of a NORM hazard as a result of refractory demolition has been conducted. Aerosol generation (mass loading), particle size distribution, and pulmonary solubility class have been investigated as a function of demolition-task description. In addition, external radiation levels in the kilns, chambers and waste piles, as a function of temperature profile and brick/operating history have been investigated.

Nanoscale Analysis on Spark Plasma Sintered Fly-Ash Bricks and their Comparative Study with SiN-Zr Refractory Bricks

2020 ◽  
Vol 12 (2) ◽  
pp. 122-128
Author(s):  
D.K. Sahoo ◽  
M.S.V.R. Kishor ◽  
D.P. Sahoo ◽  
S. Sarkar ◽  
A. Behera
Keyword(s):  
Fly Ash ◽  
Intermetallic Compounds ◽  
Spark Plasma Sintering ◽  
Maximum Temperature ◽  
Maximum Hardness ◽  
Refractory Brick ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Refractory Bricks ◽  
Sintered Product

Background: Industries such as thermal power plants use coal as a source of energy and release the combustion products into the environment. The generation of these wastes is inevitable and thus needed to be reused. In India, coals with high ash content usually between 25 to 45% are used. The refractory bricks that were used earlier in steel industries were mainly based on silica, magnesia, chrome, graphite. In modern days, several other materials were introduced for the manufacturing of refractory bricks such as mullite, chrome-magnesite, zircon, fused cast, and corundum. The materials selection for refractory brick manufacturing depends on various factors such as the type of furnace and working conditions. Objectives: The current work aims to focus on the fly-ash subjected to spark plasma sintering process with a maximum temperature of 1500 °C and pressure 60 MPa for 15 minutes and to characterize to observe the properties with respect to their microstructure. Methods: Fly-ash collected from Rourkela Steel Plant was sintered using spark plasma sintering machine at the Indian Institute of Technology, Kharagpur. The powder placed in a die was subjected to a heating rate of 600-630 K/min, up to a maximum temperature of 1500˚C. The process took 15 minutes to complete. During the process, the pressure applied was ranging between 50 to 60 Mpa. 5-10 Volts DC supply was given to the machine with a pulse frequency of 30-40 KHz. The sintered product was then hammered out of the die and the small pieces of the sintered product were polished for better characterization. The bricks collected from Hindalco Industries were also hammered into pieces and polished for characterization and comparison. Results: The particles of fly-ash as observed in SEM analysis were spherical in shape with few irregularly shaped particles. The sintered fly-ash sample revealed grey and white coloured patches distributed around a black background. These were identified to be the intermetallic compounds that were formed due to the dissociation of compounds present in fly-ash. High- temperature microscopy analysis of the sintered sample revealed the initial deformation temperature (IDT) of the fly-ash brick and the refractory brick which were found to be 1298 °C and 1543 °C, respectively. The maximum hardness value observed for the sintered fly-ash sample was 450 Hv (4.413 GPa) which is due to the formation of nano-grains as given in the microstructure. The reason behind such poor hardness value might be the absence of any binder. For the refractory brick, the maximum hardness observed was 3400 Hv (33.34 GPa). Wear depth for the sintered fly-ash was found to be 451 μm whereas for the refractory brick sample it was 18 μm. Conclusion: The fly-ash powder subjected to spark plasma sintering resulted in the breaking up of cenospheres present in the fly ash due to the formation of intermetallic compounds, such as Cristobalite, syn (SiO2), Aluminium Titanium (Al2Ti), Magnesium Silicon (Mg2Si), Maghemite (Fe2O3), Chromium Titanium (Cr2Ti) and Magnesium Titanium (Mg2Ti), which were responsible for the hardness achieved in the sample. A large difference in the maximum hardness values of sintered fly-ash and refractory brick was observed due to the hard nitride phases present in the refractory brick.

Effect of Briquetting Pressure on the Performance of In Situ Formed Sialon in Al2O3-C Refractory Bricks

2014 ◽  
Vol 881-883 ◽  
pp. 1049-1052 ◽  
Author(s):  
Nai Peng ◽  
Cheng Ji Deng ◽  
Hong Xi Zhu
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
X Ray Diffraction ◽  
X Ray ◽  
Z Value ◽  
Refractory Bricks ◽  
Scanning Electron

In this paper, the effects of briquetting pressure on the performance of in-situ formed Sialon in Al2O3-C refractory bricks are investigated. The phase compositions and microstructure of the Al2O3-C refractory were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM).The results show the briquetting pressure hardly has effect on the phase of the sintered specimens, two new phases of Sialon with a Z value of 2 and SiC formed. The micrographs of Sialon crystals have the shape of both column and tabular column, but with a cone tip in the specimens sintered at 200MPa and 300MPa and smooth tip in specimens sintered at 400MPa and 500MPa.

Life Cycle Cost Analysis of Coke Production from Delayed Coking Process

2013 ◽  
Vol 849 ◽  
pp. 380-386 ◽  
Author(s):  
Ren Jin Sun ◽  
Keng H. Chung ◽  
Siauw Ng ◽  
Hao Wang
Keyword(s):  
Carbon Dioxide ◽  
Life Cycle ◽  
Life Cycle Cost ◽  
Negative Impact ◽  
Coke Production ◽  
Life Cycle Cost Analysis ◽  
Environmental Costs ◽  
Delayed Coking ◽  
Processing Cost ◽  
Coke Producer

Life cycle cost (LCC) analysis was performed for a 1.6 million tons per year (30,000 BPD) delayed coking unit. The results show that the LCC of coke production is higher than the price of coke and profits are obtained at the expense of environmental costs. The feedstock cost accounts for a majority of LCC. The variability impacts of processing expenses and carbon dioxide (CO2) price on LCC are relative similar. This suggests that if a higher CO2 price is imposed on coke production, it is unlikely that the producer will make any effort to reduce the CO2 emissions either by improving the efficiency of coking process or implement CO2 remediation initiatives. The CO2 price increase will be considered as a processing cost increase. The green factor (GF) is predominantly dependent on coke price; an increased coke price improves the GF significantly. Increased CO2 price has a negative impact on GF, but the relative incremental impact of CO2 price on GF is less at high CO2 prices. Hence, there is little can be done to improve the GF of coke production, since the coke price is beyond the control of coke producer.

scholarly journals Continental anthropogenic primary particle number emissions

2016 ◽  
Vol 16 (11) ◽  
pp. 6823-6840 ◽  
Author(s):  
Pauli Paasonen ◽  
Kaarle Kupiainen ◽  
Zbigniew Klimont ◽  
Antoon Visschedijk ◽  
Hugo A. C. Denier van der Gon ◽  
...  
Keyword(s):  
Particle Number ◽  
Road Traffic ◽  
Agricultural Waste ◽  
Coke Production ◽  
Strong Increase ◽  
Size Distributions ◽  
Adverse Health Effects ◽  
Carbon Particles ◽  
First Results ◽  
Aerosol Cloud Interactions

Abstract. Atmospheric aerosol particle number concentrations impact our climate and health in ways different from those of aerosol mass concentrations. However, the global, current and future anthropogenic particle number emissions and their size distributions are so far poorly known. In this article, we present the implementation of particle number emission factors and the related size distributions in the GAINS (Greenhouse Gas–Air Pollution Interactions and Synergies) model. This implementation allows for global estimates of particle number emissions under different future scenarios, consistent with emissions of other pollutants and greenhouse gases. In addition to determining the general particulate number emissions, we also describe a method to estimate the number size distributions of the emitted black carbon particles. The first results show that the sources dominating the particle number emissions are different to those dominating the mass emissions. The major global number source is road traffic, followed by residential combustion of biofuels and coal (especially in China, India and Africa), coke production (Russia and China), and industrial combustion and processes. The size distributions of emitted particles differ across the world, depending on the main sources: in regions dominated by traffic and industry, the number size distribution of emissions peaks in diameters range from 20 to 50 nm, whereas in regions with intensive biofuel combustion and/or agricultural waste burning, the emissions of particles with diameters around 100 nm are dominant. In the baseline (current legislation) scenario, the particle number emissions in Europe, Northern and Southern Americas, Australia, and China decrease until 2030, whereas especially for India, a strong increase is estimated. The results of this study provide input for modelling of the future changes in aerosol–cloud interactions as well as particle number related adverse health effects, e.g. in response to tightening emission regulations. However, there are significant uncertainties in these current emission estimates and the key actions for decreasing the uncertainties are pointed out.

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