scholarly journals Near-Graphite Coke Deposit on Nano-HZSM-5 Aggregates for Methanol to Propylene and Butylene Reaction

Catalysts ◽  
2017 ◽  
Vol 7 (6) ◽  
pp. 171 ◽  
Author(s):  
Yu Sang ◽  
Aihua Xing ◽  
Chuanfu Wang ◽  
Zhihua Han ◽  
Yulong Wu
Keyword(s):  
Coke Deposit

Investigation of the coke deposit on Ni–Al2O3 and Co–Al2O3 catalysts

Carbon ◽  
2002 ◽  
Vol 40 (11) ◽  
pp. 2025-2028 ◽  
Author(s):  
J Góralski ◽  
J Grams ◽  
T Paryjczak ◽  
I Rzeźnicka
Keyword(s):  
Coke Deposit

Non-Destructive Characterisation of Coke Deposit on FCC catalyst and its Transient Evolution upon Air-Firing and Oxy-Fuel Regeneration

2021 ◽  
pp. 132998
Author(s):  
Shenyong Li ◽  
Yu Qi ◽  
Yuneng Tang ◽  
Hasan Jubaer ◽  
Baiqian Dai ◽  
...  
Keyword(s):  
Coke Deposit ◽  
Fcc Catalyst ◽  
Non Destructive

A comparative synthesis of ZSM-5 with ethanol or TPABr template: distinction of Brønsted/Lewis acidity ratio and its impact on n-hexane cracking

2018 ◽  
Vol 8 (7) ◽  
pp. 1923-1935 ◽  
Author(s):  
Tong Ma ◽  
Luoming Zhang ◽  
Yu Song ◽  
Yunshan Shang ◽  
Yanliang Zhai ◽  
...  
Keyword(s):  
Lewis Acidity ◽  
Coke Deposit ◽  
Long Lifetime

ZSM-5 by EtOH, possessing an ultra-high Brønsted/Lewis acidity ratio, has a long lifetime and suppresses coke deposit during n-hexane cracking.

scholarly journals Hydrodeoxygenation of Guaiacol over Pd–Co and Pd–Fe Catalysts: Deactivation and Regeneration

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 430
Author(s):  
Nga Tran ◽  
Yoshimitsu Uemura ◽  
Thanh Trinh ◽  
Anita Ramli
Keyword(s):  
Coke Formation ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Regeneration Ability ◽  
Co Catalyst ◽  
Fe Catalyst ◽  
Coke Deposit ◽  
Bio Oil ◽  
Before And After ◽  
Fe Catalysts

In bio-oil upgrading, the activity and stability of the catalyst are of great importance for the catalytic hydrodeoxygenation (HDO) process. The vapor-phase HDO of guaiacol was investigated to clarify the activity, stability, and regeneration ability of Al-MCM-41 supported Pd, Co, and Fe catalysts in a fixed-bed reactor. The HDO experiment was conducted at 400 °C and 1 atm, while the regeneration of the catalyst was performed with an air flow at 500 °C for 240 min. TGA and XPS techniques were applied to study the coke deposit and metal oxide bond energy of the catalysts before and after HDO reaction. The Co and Pd–Co simultaneously catalyzed the CArO–CH3, CAr–OH, and multiple C–C hydrogenolyses, while the Fe and Pd–Fe principally catalyzed the CAr–OCH3 hydrogenolysis. The bimetallic Pd–Co and Pd–Fe showed a higher HDO yield and stability than monometallic Co and Fe, since the coke formation was reduced. The Pd–Fe catalyst presented a higher stability and regeneration ability than the Pd–Co catalyst, with consistent activity during three HDO cycles.

Analysis of Fired-Heater Fouling in a Refinery Coking Unit

Volume 3 ◽  
2004 ◽  
Author(s):  
Omar Barkat ◽  
Richard J. Nyberg
Keyword(s):  
Steam Injection ◽  
Direct Costs ◽  
Critical Parameters ◽  
Opportunity Costs ◽  
Efficient Operation ◽  
Deposit Thickness ◽  
Delayed Coking ◽  
Coke Deposit ◽  
Petroleum Refineries ◽  
Cracking Process

Delayed Coking is a principal thermal cracking process utilized by petroleum refineries to decrease residual output. Fired heater performance is critical to coker unit profitability. Adversely affecting heater performance, coke deposits inside heater tubes must be removed periodically (decoked). There are three main methods of decoking fired heaters: online spalling, steam-air decoke, and pigging. For each decoking technique, the most widely-used procedures are described. Also, the merits and drawbacks of each method are discussed. A survey of industry decoking practice has been attempted as part of this study. Fire-side tube metal temperature (TMT) and heater inlet pressure (PIN) are the critical parameters used to analyze heater tube fouling. However, changes in flow rate, density, process temperature, and steam injection can cause a pass to have higher TMT or PIN than one with greater fouling. This study suggests approximation of coke deposit thickness to obtain a parameter normalized against changes in process variables. When used in conjunction with TMT and PIN, such a parameter can help in evaluating decoke effectiveness and identify the pass with least economically efficient operation. Economic analysis of fired-heater fouling considers direct costs and opportunity costs. Direct costs, such as plant utilities, fuel, in-house manpower, and outside contractor expense are assessed for each decoking method. This study also evaluates opportunity costs associated with reduction of throughput during decoking procedures. An example economic case is presented to illustrate the potential benefit of using estimated coke deposit thickness to schedule decokes.

In-Situ Continuous Coke Deposit Removal by Catalytic Steam Gasification for Fuel-Cooled Thermal Management

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
He Huang ◽  
Xia Tang ◽  
Martin Haas
Keyword(s):  
Thermal Management ◽  
Coke Formation ◽  
Hydrocarbon Fuel ◽  
Steam Gasification ◽  
Enabling Technology ◽  
Coke Deposit ◽  
Cooling Technology ◽  
Aero Engines ◽  
Deposit Removal

Fuel-cooled thermal management, including endothermic cracking and reforming of hydrocarbon fuels, is an enabling technology for advanced aero engines and offers potential for cycle improvements and pollutant emissions control. The principal engine operability issue that will affect this enabling hydrocarbon fuel cooling technology is coke formation and deposition. Furthermore, the extent to which the benefits of high heat sink cooling technology can be realized is directly related to our ability to suppress coke formation and deposition. The successful implementation of this enabling technology is, therefore, predicated on coke suppression. In situ continuous coke deposit removal by catalytic steam gasification is being developed and successfully demonstrated as a means for suppressing pyrolytic coke deposit in fuel-cooled thermal management systems for advanced aero engines. The objective of this research is to investigate the in situ continuous coke deposit removal by catalytic steam gasification for suppressing pyrolytic coke deposition using a single-tube reactor simulator under representative hypersonic operating conditions. A coke removal system removes coke deposit from the walls of a high temperature passage in which hydrocarbon fuel is present. The system includes a carbon-steam gasification catalyst and a water source. The carbon-steam gasification catalyst is applied to the walls of the high temperature passage. The water reacts with the coke deposit on the walls of the fuel passage side to remove the coke deposit from the walls by carbon-steam gasification in the presence of the carbon-steam gasification catalyst. Experimental data shows the in situ continuous coke deposit removal by catalytic steam gasification is able to reduce coke deposit rate by more than ten times.

In-Situ Continuous Coke Deposit Removal by Catalytic Steam Gasification for Fuel-Cooled Thermal Management

2012 ◽  
Author(s):  
He Huang ◽  
Xia Tang ◽  
Martin Haas
Keyword(s):  
Thermal Management ◽  
Coke Formation ◽  
Hydrocarbon Fuel ◽  
Steam Gasification ◽  
Enabling Technology ◽  
Coke Deposit ◽  
Cooling Technology ◽  
Aero Engines ◽  
Deposit Removal

Fuel-cooled thermal management, including endothermic cracking and reforming of hydrocarbon fuels, is an enabling technology for advanced aero engines and offers potential for cycle improvements and pollutant emissions control. The principal engine operability issue that will affect this enabling hydrocarbon fuel cooling technology is coke formation. Furthermore, the extent to which the benefits of high heat sink cooling technology can be realized is directly related to our ability to suppress coke formation. The successful implementation of this enabling technology is, therefore, predicated on coke suppression. In-situ continuous coke deposit removal by catalytic steam gasification is being developed and successfully demonstrated as a means for suppressing pyrolytic coke deposit in fuel-cooled thermal management systems for advanced aero engines. The objective of this research is to investigate the in-situ continuous coke deposit removal by catalytic steam gasification for suppressing pyrolytic coke deposition using a single-tube reactor simulator under representative hypersonic operating conditions. A coke removal system removes coke deposit from the walls of a high temperature passage in which hydrocarbon fuel is present. The system includes a carbon-steam gasification catalyst and a water source. The carbon-steam gasification catalyst is applied to the walls of the high temperature passage. The water reacts with the coke deposit on the walls of the fuel passage side to remove the coke deposit from the walls by carbon-steam gasification in the presence of the carbon-steam gasification catalyst. Experimental data shows the in-situ continuous coke deposit removal by catalytic steam gasification is able to reduce coke deposit rate by more than 10 times.

Metal Dusting Reaction Mechanisms

2006 ◽  
Vol 522-523 ◽  
pp. 15-26 ◽  
Author(s):  
David J. Young
Keyword(s):  
Carbon Nanotubes ◽  
Reaction Mechanisms ◽  
Copper Content ◽  
Cluster Formation ◽  
Metal Dusting ◽  
Coke Deposit ◽  
Alumina Formers

Iron and nickel, model alloys of Ni-Cu and Fe-Cr, and commercial heat resisting alloys were exposed at 650-680oC to flowing CO-H2-H2O gases which were supersaturated with respect to carbon. All ferritic materials, including chromia and alumina formers, developed a coke deposit of carbon nanotubes, the growth of which was catalysed by nanoparticles of Fe3C. Austenitic materials formed graphite filaments and clusters in association with nanoparticles of austenite. Graphite cluster formation was suppressed by alloying copper with nickel. The sensitivity of coking kinetics to alloy copper content was consistent with a mechanism involving graphite nucleation within the subsurface metal. Chromia forming alloys resisted dusting until damage to the scale could no longer be repaired by Cr2O3 regrowth, and carbon gained access to chromium – depleted metal.

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