Gasification Of Petroleum Coke Research Articles

Synergistic effect mechanism of biomass ash-derived K-Ca-Si catalytic system on syngas production and reactivity characteristics of high-sulfur petroleum coke gasification

In this study, three typical biomass ash (BA) components, KCl, CaCO3 and SiO2, are selected as model compounds to construct BA-based key ternary component system for petroleum coke (PC) gasification. Gas product analysis was conducted using gas chromatography to study the influence of different catalysts on the gas product distribution, gas yield and carbon conversion of PC gasification, and clarify the synergistic effects of binary and ternary components in K-Ca-Si catalytic system. In addition, electron scanning microscopy (SEM) and Raman techniques are used to characterize the physicochemical structure of gasification semi-char to reveal the synergistic mechanism of K-Ca-Si system. The results show that the yield of different gases is ordered as H2 > CO > CO2 and the increment of H2 yield, CO yield, syngas yield and carbon conversion in K-Ca-Si catalytic system is 43.41 mmol/g, 26.67 mmol/g, 80.37 mmol/g and 0.49, compared with single PC gasification, respectively. By comparing the theoretical and actual value of gas yield and carbon conversion, it is found that there are synergistic catalytic effects for K-Ca-Si ternary catalyst, but Si will inhibit the activity of K and Ca. Coupled with SEM and Raman analysis, synergistic mechanism of ternary catalytic system can be revealed. KCl and CaCO3 reduce the graphitization degree of semi-char by reacting with carbon matrix, and CaCO3 can stimulate the pore structure development of semi-char, which accelerate reaction between KCl and carbon matrix to form intermediate active sites, thus favoring gasification reaction and exhibiting a synergistic effect. SiO2, on the other hand, will combine with KCl and CaCO3 to form inert silicates, resulting in the deactivation of KCl and CaCO3. It could be concluded that for high K-high Ca-low Si ternary catalytic system, KCl and CaCO3 would still show a synergistic effect due to higher CaCO3 content than SiO2.

Preparation of autoclaved-aerated concrete with waste ash of petroleum coke gasification

ABSTRACT In this paper, a novel route for the utilisation of petroleum coke gasification ash in the preparation of autoclaved-aerated concrete (AAC) is presented. The waste ash along with quartz sand, cement, lime, and gypsum are used as the primary raw materials, with aluminium powder paste serving as the pore-forming agent. The effect of incorporating petroleum coke gasification ash on the dry density and thermal conductivity of the resulting AAC was investigated. The results indicate that the thermal insulation performance of AAC is significantly enhanced by reducing the thermal conductivity coefficient upon the addition of treated petroleum coke gasification ash. At a 40% ash content, the AAC exhibits remarkable performance that meet the requirements of A2.5B05 in GB 11,968-2006, with compressive strength higher than 2.5 MPa and dry density lower than 525 kg m−3. Furthermore, the study examined the optimal calcium silicon ratio after the addition of the ash, with the results demonstrating that AAC prepared with a ratio of 0.25–0.26 exhibits the best compressive strength and dry density. The present study offers a novel perspective on waste management, which carries substantial significance for both the environmental and construction industries.

Mineral evolution and catalytic mechanism in catalytic gasification of petroleum coke with coal/biomass ash

This work investigated the formation and transformation of minerals in the catalytic gasification of petroleum coke with different characteristics of ash, and further revealed the catalytic mechanism. An isothermal gasification experiment under H2O atmosphere was conducted on a self-designed thermogravimetric analyzer. The results show that biomass ash has better catalytic gasification effect due to its higher active mineral content. Simultaneously, coal/biomass ash can effectively change the petroleum coke structure during gasification, and promote the decomposition of C = C, C–C, thiophene and sulfoxide in petroleum coke. The good correlation (correlation coefficient is 0.96) between the structural parameters (ID1/IG, ID3/IG and IG/IALL) indicates that only the mineral elements with catalytic activity in the ash can effectively change the structure of petroleum coke. Sulfur content in petroleum coke at high H2O concentration does not combine with minerals to form sulfide or sulfate, which leads to the deactivation of minerals. The results also show that the catalytic gasification effect of ash is affected by two factors: melting characteristics and the content of catalytic active minerals. At low addition ratio (≤20 %), the catalytic effect of ash mainly depends on the content of active minerals in ash. At high addition rate (≥20 %), the fluidity advantage brought by ash melting begins to play an important role.

Catalytic Gasification of Petroleum Coke with Different Ratios of K2CO3 and Evolution of the Residual Coke Structure.

The catalytic gasification of petroleum coke with different ratios of K2CO3 was investigated by a thermogravimetric analyzer (TGA) using the non-isothermal method. The initial, peak, and final gasification temperatures of the petroleum coke decreased greatly as the amount of K2CO3 increased, and the catalytic reaction became saturated at a concentration of K+ higher than 5 mmol/g; with the further increase in catalyst; the gasification rate varied slightly, but no inhibition effect was observed. The vaporization of the catalyst was confirmed during the gasification at high temperatures. The structural evolution of the residual coke with different carbon conversions was examined by X-ray diffraction (XRD), Raman spectroscopy, and N2 adsorption analyses during gasification with and without the catalyst. The results showed that the carbon crystallite structure of the residual coke varied in the presence of the catalyst. As the carbon conversion increased, the structure of the residual coke without the catalyst became more ordered, and the number of aromatic rings decreased, while the graphitization degree of the residual coke in the presence of the catalyst decreased. Meanwhile, the surface area and pore volume of petroleum coke increased in the gasification process of the residual coke, irrespective of the presence of the catalyst. However, the reactivity of the residual coke did not change much with the variation in the carbon and pore structure during the reaction.

Investigation of Petroleum Coke Gasification with CO2/H2O Mixtures and S/N Removal Mechanism via ReaxFF MD Simulation.

The removal of environmentally harmful S/N is crucial for utilization of high-S petroleum coke (petcoke) as fuels. Gasification of petcoke enables enhanced desulfurization and denitrification efficiency. Herein, petcoke gasification with the mixture of two effective gasifiers (CO2 and H2O) was simulated via reactive force field molecular dynamics (ReaxFF MD). The synergistic effect of the mixed agents on gas production was revealed by altering the CO2/H2O ratio. It was determined that the rise in H2O content could boost gas yield and accelerate desulfurization. Gas productivity reached 65.6% when the CO2/H2O ratio was 3:7. During the gasification, pyrolysis occurred first to facilitate the decomposition of petcoke particles and S/N removal. Desulfurization with the CO2/H2O gas mixture could be expressed as thiophene-S → S → COS → CHOS, thiophene-S → S → HS → H2S. The N-containing components experienced complicated mutual reactions before being transferred into CON, H2N, HCN, and NO. Simulating the gasification process on a molecular level is helpful in capturing the detailed S/N conversion path and reaction mechanism.

ReaxFF molecular dynamics study of co-combustion of waste tires with petroleum coke gasification residue: Combustion characteristics, gas evolution and micro mechanism

Solid wastes such as waste tires (WT) and petroleum coke gasification residue (PCGR) could be used as fuels to realize the recovery of resources. The detailed composition of WT and PCGR was determined in this study through the proximate and ultimate analyses, FTIR, XPS, and 13C NMR characterization. Based on experimental characterization results, molecular models of WT (C557H802O16S4N3) and PCGR (C156H61O5S3N) were constructed. Then, the co-combustion characteristics of WT and PCGR were in-depth investigated via the reactive force field molecular dynamics (ReaxFF MD) simulations. The migration pathways of N/S during combustion in both O2 and O2/N2 atmospheres were also elucidated. Meanwhile, the evolution of specific products with oxygen concentration and temperature was investigated. The results indicated the oxidation process began with thermal decomposition to form small fragments, which were next attacked by O radicals to generate inorganics. Additionally, the blending combustion was promoted as the molar fraction of the WT increased. The PCGR decomposed and burnt faster in fuel-lean conditions. Besides, higher temperature could accelerate the combustion process. The pyrrole/pyridine was converted to HCN and NHx in the first step and then oxidized to NOx. The production of NOx was significantly higher in the O2/N2 atmosphere than that in the O2 atmosphere. The main product was NO, with a small amount of NO2. The conversion of thiol to HS and thiophene S to COS was also observed. The COS easily reacted with H atoms to form HxS. In O2/N2 environment, CNS and elemental sulfur were formed due to the N-rich atmosphere.

Effect of CaO/Fe2O3 on ash fusibility during petroleum coke gasification and combustion

Ash fusibility is closely related to ash melting, sintering and slagging, which is commonly used to guide the utilization of petroleum coke in boiler and gasifier. Calcium (Ca) and iron (Fe) show significant influence on the ash fusibility of petroleum coke. To quantify the influence of CaO/Fe2O3 mass ratio on petroleum coke ash fusibility, ash fusion temperatures (AFTs) analysis, X-ray diffraction (XRD), and FactSage were applied to investigate the characteristics of petroleum coke ash fusibility with various CaO/Fe2O3 mass ratios. The results showed that AFTs were closely associated with the CaO/Fe2O3 ratio and showed different performances in different atmospheres. In the reducing atmosphere, with the increasing of CaO/Fe2O3 ratio, the AFTs presented in turn a rapid decrease (from 0 to 2) and a smooth region (from 2 to ∞). The rapid decrease of AFTs was mainly attributed to the disappearance of high-melting point coulsonite (FeV2O4) and the formation of low temperature eutectics anorthite (CaAl2Si2O8) and gehlenite (Ca2Al2SiO2). The formation of high-melting point calcium orthosilicate (Ca2SiO4) inhibited the formation of CaAl2Si2O8/Ca2Al2SiO2 to keep the AFTs at a stable level. In the oxidizing atmosphere, with the increasing of CaO/Fe2O3 ratio, the AFTs presented in turn a rapid decrease (from 0 to 1), a smooth region (from 1 to 5), and a fast decrease once again (from 5 to ∞), respectively. The decline of AFTs was attributed to the substitution of NiFe2O4 by fusible minerals (Ca2V2O7/CaAl2Si2O8). The synergy effect of the refractory SiO2 and fusible minerals prevented the further decline of the AFTs.

Concept design, technical performance, and GHG emissions analysis of petroleum coke direct chemical looping hydrogen highly integrated with gasification for methanol production process

Petroleum coke gasification for methanol production process has excellent application prospects for the clean utilization of high‑sulfur coke while limiting pollutant emissions from coke combustion. However, the process still suffers from high-energy use and a large CO2 generation caused by composition adjustment. This study proposes a novel petroleum coke chemical looping hydrogen-assisted gasification process for methanol production. Mass-energy coupling is realized by replacing the water gas shift unit with the chemical looping hydrogen unit, and the high temperature gasified gas heats the fuel reactor and in turn the feedstock. Two chemical looping hydrogen scenarios with an operating pressure of 3.0 and 0.1 MPa are considered. The methanol exergy can be increased from 484 to 1030 and 1028 MW by doubling the petroleum coke consumption through the chemical looping integration. The exergy efficiency of the new process is correspondingly increased from 51.6 to 57.1 and 55.2 % with 63.02 and 63.71 % reductions in direct CO2 emissions, as compared to the only gasification route. The calculated life cycle energy consumption and greenhouse gases emissions of the new processes are 40.02/43.84 GJ/t and 693/1055 kg CO2 eq/t, 15.14/7.05 % and 49.09/22.45 % lower than that of the benchmark process. The integration of high-pressure chemical looping technology can introduce significant technical and environmental benefits for methanol production from the petroleum coke.

Parameter optimization and exergy efficiency analysis of petroleum coke-to-hydrogen by chemical looping water splitting process with CO2 capture and self-heating

The petroleum coke-to-hydrogen process is promising since the output of high-sulfur petroleum coke is increasing year by year, the pollution emissions of its combustion for power generation are serious, and the refinery needs a lot of hydrogen. Therefore, this study establishes the process model and conduct the parameter optimization of the petroleum coke direct chemical looping hydrogen production process. The optimized mass ratios of oxygen carrier (Fe2O3), steam, and air to petroleum coke are 12.71, 2.98, and 2.18; however, that are 12.71, 1.79–2.08, and 4.53–5.32 when the proportion of the reduced oxygen carrier entering steam reactor is reduced from 100% to 60–70%, which can be operated in a self-heating mode with air preheating temperature of 278.54–816.80 ℃. When the proportion is increased from 60% to 65.32% and 70%, the product exergy of hydrogen is increased from 454.58 MW to 494.92–530.36 MW with about 100% CO2 capture and the exergy efficiency is therefore increased from 59.56 to 60.75% to 62.32–63.59% and 62.65–63.91%. This paper also studies the sulfur distribution and existing forms of sulfides. Finally, this study found that the exergy efficiency of the chemical looping hydrogen process with the proportion of 65–70% is significantly higher than that of the hydrogen production process by petroleum coke gasification.

CO2 gasification of petroleum coke with use of iron-based waste catalyst from F-T synthesis

In this study, the influence of iron-based waste catalyst (IWC) from F-T synthesis as a cheap additive on the gasification reaction characteristics of petroleum coke (PC) with CO2 at 1000–1300°C was investigated by thermogravimetric analyzer. The gasification kinetics of PC was analyzed by free model method. The surface complexes of PC were determined through temperature-programmed desorption (TPD) methods to reveal the mechanism of IWC catalytic PC gasification. The results show that IWC is an efficient PC gasification catalyst and can reduce the activation energy of PC CO2 gasification. The induction of iron in IWC makes the surface of PC have more activated carbon sites, thereby forming more oxygen-containing intermediates, and the cyclic redox reaction of iron can act as an oxygen carrier to accelerate the reaction of CO2 and carbon, both of these may be the essential reasons for the CO2 gasification of PC catalyzed by IWC.

Effect of Cao/Fe2o3 on Ash Fusibility During Petroleum Coke Gasification and Combustion

Effect of Cao/Fe2o3 on Ash Fusibility During Petroleum Coke Gasification and Combustion

The fate of char structure and active groups in petroleum coke gasification in a drop tube furnace

A research on the fate of active groups from three typical petroleum cokes (petcokes) during gasification in a drop tube furnace have been presented. The results showed that the relative reduction (R) index can be used to assess the gasification reactivity of petcoke. The decomposition of side chain reaction of dealkylation is easier to proceed. Petcoke with a relative ordered degree of char structure has an energy barrier resulting in the transformation from the ordered graphitic carbon structure to amorphous carbon structure occurred only after the temperature reaches 1200 °C. It is recommended to control the petcoke gasification temperature above 1200 °C. A high temperature is beneficial for the conversion of oxygen-containing functional groups to hydroxyl groups. Petcoke with high ash content promotes the decomposition of functional groups to form active radicals, which favors the formation of amorphous carbon and, consequently, more active sites resulting in the high gasification reactivity. The high temperature gasification can make the stable active radicals (aromatic hydrocarbons groups) to break up the thermal barrier and convert to active radicals (aliphatic hydrocarbons and side chains on aromatic structure, oxygen functional groups and hydroxyl groups). The active radicals react with oxygen adsorbed on the carbon surface to generate CO, H2, CH4, etc.

Flow battery electrolyte from carbon black incineration fly ash: A feasibility study of an environment friendly disposal process.

Fly ash represents a kind of finely divided solid waste which is derived from industrial or municipal waste incineration and contains various metal elements. In this work, we focus on the waste-to-resource conversion of one fly ash which is generated from the incineration of petroleum coke gasification waste. The leaching behaviors and waste conversion of this fly ash to value-added products under different treatments were investigated. The majority of the identified elements in leachate demonstrated different leaching patterns as the species of leached element from fly ashes depend on the chemical properties of leaching agents. Moreover, A pathway is developed to harvest toxic vanadium from this fly ash, and the vanadium-containing leachate can be further converted into electrolyte for vanadium redox flow battery (VRFB). The vanadium electrolyte was synthesized by using fly ash leachate as the resource materials in two different ways afterwards: reducing vanadium in the leachate directly (electrolyte from leachate) and synthesizing V2O5 from leachate as the intermediate product (electrolyte from leachate-derived V2O5). The electrochemical behavior and performance of these electrolytes were analyzed to investigate the feasibility of these approaches. The measurement of electrochemical performance proves that the electrolyte from leachate-derived V2O5 is comparable to the standard electrolyte in terms of columbic efficiency (CE), energy efficiency (EE) and stability. Based on experimental results, our research provides a potential solution for the establishment of vanadium flow battery plant. Cost-benefit analysis proves that the payback period of electrolyte synthesized from alkaline leachate and leachate-derived V2O5 is 2.1years and 1.0year, respectively.

In-situ catalytic effect of potassium on petroleum coke gasification with a Mn ore-based oxygen carrier

Potassium was used as a catalyst for Chemical Looping Gasification (CLG) process in order to accelerate petroleum coke gasification. Two catalytic modes were applied, one was to use potassium to modify coke and another one was to a Mn ore based oxygen carrier. The in-situ catalytic effect of potassium during CLG process was experimentally evaluated in a fluidized bed. The influences of reaction temperature, oxygen carrier to fuel ratio, potassium introduction modes and cycles on syngas yields and distribution, carbon conversion and potassium evolution were investigated. Results indicated that both catalytic modes can accelerate coke conversion. Beneficial coke conversion was brought into play after several cycles’ activation for the potassium-modified Mn ore oxygen carrier applied for CLG process. Its activation with cycles led to an increase of the average carbon conversion rate, obtaining a stable value of 4.39%/min, higher than the one of 3.91%/min for the condition without potassium addition. Part of potassium on the surface of oxygen carrier was partially lost in the initial cycles and then fixed on the oxygen carrier particles. The remaining potassium existed in the form of K2Si4O9. The catalytic model of using the potassium to modify coke for CLG process accelerated coke conversion remarkably, obtaining an average carbon conversion rate of 7.8%/min, which is 1.78 times higher than that of using potassium to modify the Mn ore. Besides, the potassium into the reaction process had little effect on the oxygen carrier’s reactivity, but accelerated the water gas shift reaction, producing more H2 and less CO in the syngas.

Enhancement of Desulfurization Capacity with Cu-Based Macro-Porous Sorbents for Hydrogen Production by Gasification of Petroleum Cokes

Macro-porous alumina was used as a support for a pellet-type Cu-based desulfurization sorbent in the gas purification process for producing blue hydrogen by the gasification of petroleum coke. The effects of the macro-porous alumina on the pellet-type sorbents in reducing the gas diffusion resistance into the pores were investigated. The results showed that the macro-porous alumina enhances the diffusion resistance, resulting in an improved sulfur capacity of CuO absorbents. Such effects were more significant on the pellet type CuO absorbents than the powder type. In addition, CO production was observed experimentally during the desulfurization reaction of carbonyl sulfide (COS) at low temperatures (~473 K). Density functional theory calculations were also performed to understand the kinetics of desulfurization and CO production. The simulation results predicted that the kinetics of desulfurization is strongly affected by the local surface environment. The CO generated from C–O bond breaking from COS had a lower adsorption energy than the CO2 formation. These results suggest that the Cu-based desulfurization sorbent has potential catalytic activity for producing CO from COS dissociation.

Addition of V2O5 and V2O3 to the CaO–FeO–Fe2O3–MgO–SiO2 database for vanadium distribution and viscosity calculations

Vanadium oxides were added to the existing GTOx database because of its important role in the ferro-titanium metallurgy as well as in petroleum coke gasification. The CaO–FeO–Fe2O3–MgO–SiO2 system is a part of GTOx database and is chosen because of the existence of experimentally determined vanadium distributions between vanadium ferroalloys and metallurgical slags. The CaO–FeO–Fe2O3–MgO–SiO2–V2O3–V2O5 system including all binary and ternary sub-systems was thermodynamically assessed using all available experimental data. Vanadium was introduced into the thermodynamic description of solid solution phases such as MeO, Spinel, Corundum and Ca2SiO4-α using available experimental information. Particular attention was given to the phase Spinel which forms the wide completely miscible solid solution Fe3O4–FeV2O4–MgV2O4–MgFe2O4. The thermodynamic description of the metallic vanadium containing systems was taken from the SGTE alloy database. With the knowledge about the complex behavior of vanadium in slags as well as in liquid metal alloys it is possible to calculate the vanadium distribution ratios (V)/[V] between iron melts and slags in a wide range of temperatures and compositions, corroborating the validity of the model under reducing conditions. The additionally developed viscosity model shows good agreement between the calculated and experimental values in vanadium-containing slags.

Kinetics of Gasification and Co-gasification of Petcoke and Coal

Co-gasification of petroleum coke with other carbonaceous material is making significant inroads in the quest for efficient utilization of petroleum coke. In the present work, gasification and co-gasification of petroleum coke and low-grade Indian coal was studied by thermogravimetric analysis at three heating rates, 10, 20, 30 °C min−1 under oxygen atmosphere. Physicochemical characterization of petroleum coke revealed that it contains significantly high fixed carbon and has high calorific value with low ash content vis-a-vis coal sample. It was observed that with the increase in heating rate, the ignition and the burn out temperature also increases. Kinetic parameters were calculated by employing commonly used two model-free isoconversional methods, i.e., Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) based on TGA data. The activation energies of petcoke and blend (petcoke + coal) calculated by KAS and FWO methods were found to be 126.75 and 109.94 kJ mol−1, and 128.3 and 111.85 kJ mol−1, respectively. Activation energy values obtained by both the methods demonstrate that the blend requires lesser energy than gasification of petcoke alone. Gasification of blend was found to follow complex multi-step nature of kinetics. Overall, the findings demonstrate that co-gasification could be a practical approach for energy recovery from the petcoke–coal mixture than gasification of petcoke alone.

Valorizing petroleum coke into hydrogen-rich syngas through K-promoted catalytic steam gasification

Hydrogen-rich syngas was successfully produced from catalytic steam gasification of petroleum coke. This work studied the steam gasification of petroleum coke over KOH, K2CO3, KNO3, CaO, Fe2O3, K2CO3–CaO and K2CO3–Fe2O3 in a pressurized fixed bed. KOH and K2CO3 demonstrated good catalytic activity compared with other catalysts. The carbon conversion efficiency (CCE) increased from 14.7 wt% to 61.4 wt% and 87.9 wt% after adding 10 wt% K2CO3 and 10 wt% KOH, respectively, and H2 content increased from 60.9 vol% to 66.7 vol% and 64.2 vol%. The increase of gasification temperature and pressure resulted in the increase of CCE. However, raising temperature was beneficial to the increase of H2 and CO contents, while the elevated pressure was in favor of the formation of CH4. In addition, the K-catalytic steam gasification of petroleum coke accorded with the oxygen transfer and intermediate hybrid mechanism.

Comparison of CO2 gasification reactivity and kinetics: petcoke, biomass and high ash coal

It is desirable to exploit biomass energy along with coal and petcoke through gasification, and understanding the differences between petroleum coke (petcoke), coal and biomass gasification behaviour becomes very essential. Consequently, present investigation compares gasification components of petcoke, sawdust and high ash coal with their physico-chemical properties under isothermal conditions in CO2 atmosphere in the temperature range of 1173–1623 K. Physico-chemical characterisation includes proximate and ultimate analyses, porous structure analysis by Brunauer-Emmett-Teller (BET) surface area from nitrogen (N2) adsorption isotherm, ash composition analysis and ash fusion temperature. The effects of temperature and nature of different solid fuels on gasification reactivity have been discussed. Gasification kinetics has been investigated using two nth-order kinetic models, such as homogeneous model (HM) and shrinking core model (SCM). Influence of diffusion resistance on gasification behaviour of different solid fuels is also reported. Thus, the present study will be helpful to realise the effects of high ash in gasification behaviour as well as in designing and modelling of the suitable gasifier and to establish optimum gasification conditions for petcoke, biomass and high ash coal.

Kinetics of co-gasification of rice husk biomass and high sulphur petroleum coke with oxygen as gasifying medium via TGA

Co-gasification of biomass with petroleum coke is making significant inroads for utilizing the energy content of both biomass and petroleum coke judiciously. In the present work, detailed physico-chemical characterization of the feed materials via standard methods, gasification of individual rice husk (RH) biomass, high sulphur petroleum coke (PC), and co-gasification of RH biomass and high sulphur PC, at three heating rates (10, 20, and 30 °C/min) via thermogravimetric analyzer was investigated. The obtained TGA data was analyzed by employing model-free isoconversional methods, viz. Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) for the determination of kinetic parameters. Activation energy determined from model-free isoconversional KAS and FWO methods for petroleum coke gasification alone was found to be 126.75 and 128.3 kJ/mol, respectively, whereas for the RH + PC (3: 1) blend, it was 86.85 and 87.84 kJ/mol, respectively. Reactivity of PC was found to increase in presence of RH during co-gasification.