Steam Gasification Of Petroleum Coke Research Articles

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.

Effect of occurrence modes of nickel and vanadium on gasification characteristics of petroleum coke

This study investigates the effect of the occurrence modes of nickel (Ni) and vanadium (V) on char structure and reactivity during the steam gasification of petroleum coke (petcoke) in a fixed-bed reactor. Sequential extraction is applied to obtain the occurrence modes of Ni and V. Results indicates that Ni and V associated with the exchangeable form strongly promotes gasification reactivity and increases the methane yield by accelerating aromatic structure decomposition. The carbonates restrain pore structure development by increasing the graphitization degree to lower reactivity and gas yields. The exchangeable form and Fe-Mn oxides are beneficial to the micropore structure development. In comparison with continental petcoke, marine facies form highly disordered structures because high Ni and V contents can promote the pore structure formation. The carbonates strongly lower the reactivity of char and are unfavorable for the heat value of syngas, which should be selectively removed before gasification.

Simulation analysis of steam gasification of petroleum coke with CaO

The work deals with the effect of calcium oxide adsorption on the production of hydrogen and methane in steam gasification of petroleum coke using Aspen Plus process simulator. The prediction accuracy of the proposed model is verified by comparing with the existing experimental results. The effects of water vapor flux, the mass ratio of calcium oxide to petroleum coke, pressure, temperature on hydrogen or methane gasification from petroleum coke steam are studied. The production of hydrogen from petroleum coke gasification requires a low temperature and low pressure environment, while increasing the flow of water vapor is beneficial to the production of hydrogen. Maximum H2 volume fraction of 87.3% is obtained at a temperature of 600 °C, a pressure of 0.1 MPa, the mass of steam to petroleum coke is 1, and the mass of CaO to petroleum coke is 3. The H2 and CO2 volume fractions are found to be increased and decreased by 20% and 27.8% respectively, when compared with the corresponding non-CaO case. The production of methane from petroleum coke gasification requires a low temperature and high pressure environment, while decreasing the flow of water vapor is beneficial to the production of methane. Maximum CH4 volume fraction of 63% is obtained at a temperature of 600 °C, a pressure of 1 MPa, the mass of steam to petroleum coke is 1, and the mass of CaO to petroleum coke is 1. The CH4 and CO2 volume fractions are found to be increased and decreased by 14.4% and 21% respectively, when compared with the corresponding non-CaO case.

Investigation of the Transformation Behavior of Nickel and Vanadium during Steam Gasification of Petroleum Coke

The gasification of petroleum coke (petcoke) can cause fouling and erosion problems. In this study, the evolution of Ni and V during steam gasification is investigated in a fluidized bed from 800 to 1100 °C. The occurrence modes determined by the sequential extraction show that raw petcoke contains diversified Ni forms, whereas V is dominated by organic matter and residual form. The organic matter is rapidly converted to residual form. The Ni in residual form is partially released, whereas the V in residual form is considerably converted to other forms. The volatilization of Ni is positively correlated with the temperature and sulfur content, whereas V has a positive correlation with the exchangeable form. The exchangeable form of V is conducive to forming a well-developed pore structure, whereas carbonates play the opposite role. Under the practical fluidized bed gasification, Ni tends to cause erosion, especially for continental petcoke, whereas V is inclined to cause slagging and fouling.

Reactivity and kinetics for steam gasification of petroleum coke blended with black liquor in a micro fluidized bed

Steam gasification of petroleum coke catalyzed by black liquor (BL) was conducted in a micro fluidized bed to investigate the reaction characteristics and kinetics, including the effects of temperature, particle size, BL loading amount and oxygen content in steam on product gas composition and reaction rate. The completion time of petroleum coke steam gasification at 900°C decreased from 120min for pure coke to about 40min for the coke blended with 10wt.% BL. The corresponding hydrogen fraction in the produced syngas increased by 9vol.%. The gasification reaction was further enhanced by introducing a small amount of oxygen into the steam. The shrinking core model (SCM) and homogenous model (HM) were used to calculate the kinetics of petroleum coke gasification, finding that SCM enabled the better correlation with experimental data than HM did. Using SCM the activation energy was 77kJ·mol−1 for coke gasification with 10wt.% BL as catalyst, which was much lower than 120kJ·mol−1 for the case without BL blended. The activation energy was further reduced to about 63kJ·mol−1 by adding 5% oxygen into the steam, showing a synergistic effects of BL and O2 on petroleum coke gasification. The study also justified the feasibility of syngas production from petroleum coke via fluidized bed gasification.

A Semi-empirical Kinetic Model for Simulating the Steam Gasification of Petroleum Coke Catalyzed by K2CO3

K2CO3-catalyzed steam gasification of petroleum coke at 650–850°C was performed using a laboratory fixed-bed reaction system with an on-line quadruple mass spectrometer. Due to the catalytic effect of K, the catalytic gasification rate exhibited a maximum in the high carbon conversion range, which was different from that in the case of non-catalytic gasification. When the random pore model was used to simulate the catalytic gasification process of petroleum coke, great deviations were found at high carbon conversions. A semi-empirical model (extended random pore model) was proposed on the base of the random pore model. It was found that the extended random pore model could describe well the catalytic gasification profile in the whole carbon conversion range, and the two empirical parameters (α and β) introduced in the extended random pore model could be well correlated with the gasification temperature.

Experimental Study of Petroleum Coke Steam Gasification Catalyzed by Black Liquor in a Fluidized Bed

Steam gasification of petroleum coke with black liquor (BL) was conducted in a fluidized bed. The reaction characteristics was investigated to allow an insight into the catalytic mechanism, and thus to justify the feasibility of H2 production from petroleum coke using the fluidized bed gasification technology. The results showed that BL could not only greatly enhance the gasification rate but also increase the H2 content in the produced gas. In comparison with non-catalytic gasification, the temperature of realizing similar reaction activity decreased by about 200°C when loading with 10wt.% BL, and the corresponding hydrogen amount increased by about 9 percentage point.

The Physicochemical Properties and Catalytic Characteristics of Different Biomass Ashes

Steam gasification of petroleum coke catalyzed by different biomass ashes and different biomass ash loadings were investigated to examine the catalytic effects not only on the gasification activity but also on the H2 production characteristics, and the physicochemical properties of three biomass ashes (rice straw ash, wheat straw ash, and cotton straw ash) were also analyzed. The total contents of alkali metals (K and Na), alkaline earth metals (Ca and Mg), and transition metal (Fe) in RSA, WSA, and CSA were separately up to 22.63, 43.88, and 55.68%, and a large quantity of catalytic components (such as KCl, K2SO4, etc.) were contained in these biomass ashes. The biomass ashes could not only enhance the gasification activity of petroleum coke effectively, but also promote the H2 production greatly. The ordering of the catalytic action of various biomass ashes was CSA > WSA > RSA. The increasing loading of biomass ash was favorable for elevating the gasification activity of petroleum coke and promoting the H2 production, and the effects of the redundant biomass ash loading on those were very little. The mineral matters in biomass was conducive to improve the gasification activity of petroleum coke during the co-gasification processes and to promote the H2 production to produce syngas with high purity H2 (up to 61%) and no virtual CH4 at relatively low temperatures.

The Reactivity and H2 Production Characteristics of Petroleum Coke-steam Gasification Catalyzed by Potassium Salts

Potassium salts-catalyzed steam gasification of petroleum coke for H2 production was performed using a laboratory fixed-bed reaction system with an on-line quadruple mass spectrometer. The gasification reactivity and H2 production characteristics of petroleum coke-steam gasification catalyzed by potassium salts were investigated mainly. The potassium salt catalysts could not only enhance effectively the gasification reactivity of petroleum coke, but also promote greatly the H2 production. The catalytic action of various potassium salts was ordered as K2CO3 > KAc > KNO3 > K2SO4 > KCl. The increasing catalyst loading could promote the H2 production of petroleum coke gasification. However, different potassium salts almost had no effect on the distribution of product gases. It was feasible to produce syngases with high H2 (up to 60%) and no virtual CH4 (below 0.1%) through the catalytic steam gasification of petroleum coke at relatively low temperatures.

Potassium-catalyzed steam gasification of petroleum coke for H2 production: Reactivity, selectivity and gas release

Potassium-catalyzed steam gasification of petroleum coke for H2 production was performed using a laboratory fixed-bed reaction system with an on-line quadruple mass spectrometer. The gasification reactivity, gasification selectivity and gas release for the catalytic gasification were investigated, compared with the non-catalytic gasification. The catalytic gasification could not only effectively promote these reactions (the water–carbon reaction, the water–gas shift reaction and the methane-steam reforming reaction), but also elevate greatly the gasification selectivity towards CO2 (a high gasification selectivity towards CO2 meant a high H2 production). A quantitative calculation method for the gasification selectivity towards CO and CO2 was proposed to further understand the catalytic behaviors of catalysts. In the case of catalytic gasification, the gasification temperature had opposite effects on the gasification reactivity and the gasification selectivity towards CO2, suggesting that there existed an optimum gasification temperature (about 750°C) for H2 production from the potassium-catalyzed steam gasification of petroleum coke. In addition, petroleum coke could be feasibly utilized as the feedstocks for the catalytic steam gasification to produce gases with high H2 (55.5–60.4%) and virtually no CH4 (below 0.1%).

Hydrogen production by steam-gasification of petroleum coke using concentrated solar power—III. Reactor experimentation with slurry feeding

We report on the experimental evaluation of a 5 kW solar chemical reactor for the steam-gasification of petcoke, carried out in a high-flux solar furnace. A petcoke–water slurry was continuously injected into a solar cavity-receiver to create a vortex flow directly exposed to concentrated solar radiation. For a nominal reactor temperature of 1500 K , a water–petcoke molar ratio of 4.8, and a residence time of 2.4 s , the maximum degree of petcoke conversion was 87%. Typical syngas composition produced was 62% H 2 , 25% CO, 12% CO 2 , and 1% CH 4 . The solar energy conversion efficiency—defined as the portion of solar energy absorbed as chemical energy and sensible heat—attained 17%. The effect of varying the particle size (range 8.5– 200 μ m ) and slurry stoichiometry (range 2.1–6.3) on the degree of chemical conversion and energy conversion efficiency was examined.

06/02558 Hydrogen production by steam-gasification of petroleum coke using concentrated solar power — II Reactor design, testing, and modelingZ'Graggen, A. et al. International Journal of Hydrogen Energy, 2006, 31, (6), 797–811

06/02558 Hydrogen production by steam-gasification of petroleum coke using concentrated solar power — II Reactor design, testing, and modelingZ'Graggen, A. et al. International Journal of Hydrogen Energy, 2006, 31, (6), 797–811

Kinetic Modeling for the Combined Pyrolysis and Steam Gasification of Petroleum Coke and Experimental Determination of the Rate Constants by Dynamic Thermogravimetry in the 500−1520 K Range

The detailed kinetic mechanisms for the combined endothermic pyrolysis and steam gasification of petroleum coke are formulated using elementary chemisorption and reaction steps. The pyrolysis model is based on a linear combination of first-order decomposition rates of pseudo components. The gasification model is based on the oxygen-exchange mechanism describing reversible O-transfer surface reactions followed by a unidirectional gasification step, and on an extended mechanism describing, in addition, reversible steam sorption as OH/H groups and irreversible surface chemistry. The kinetic rate laws of Langmuir−Hinshelwood type are derived by assuming sorption equilibrium and by considering inhibition due to recombination of adsorbed oxygen and competition for active sites. The Arrhenius parameters of the rate constants for the pyrolysis and gasification of Flexicoke and Petrozuata Delayed coke are experimentally determined by dynamic thermogravimetric analyses with Ar, H2O, CO2, and H2O−CO2 mixtures in the...

Hydrogen production by steam-gasification of petroleum coke using concentrated solar power—II Reactor design, testing, and modeling

The solar chemical reactor technology for the steam-gasification of petcoke is presented. The reactor features a continuous vortex flow of steam laden with petcoke particles confined to a cavity receiver and directly exposed to concentrated solar radiation. A 5 kW prototype reactor tested in a high-flux solar furnace in the range 1300–1800 K yielded up to 87% petcoke conversion in a single pass of 1 s residence time. The solar-to-chemical energy conversion efficiency attained 9% without accounting for the product's sensible heat, and 20% when the sensible heat is recovered for steam generation and pre-heating. A steady-state process model that couples radiative heat transfer with the reaction kinetics is validated with experimental data and used for optimization and scale-up of the reactor design.

Hydrogen production by steam-gasification of petroleum coke using concentrated solar power—I. Thermodynamic and kinetic analyses

The steam-gasification of petroleum coke using concentrated solar radiation as the source of high-temperature process heat is proposed as a viable transition path towards solar hydrogen production. The advantages are three-fold: (1) the calorific value of the feedstock is upgraded; (2) the gaseous products are not contaminated by the byproducts of combustion; and (3) the discharge of pollutants to the environment is avoided. The thermodynamics and kinetics of the pertinent reactions are analyzed for two types of petroleum coke: Flexicoke and Petrozuata Delayed coke. The net process is endothermic by about 50% of the feedstock's LHV, and proceeds at above 1300 K to produce, in equilibrium, an equimolar mixture of H 2 and CO. A Second-Law analysis on the processing of this syngas to H 2 (by water–gas shift followed by H 2 / CO 2 separation) for power generation in a fuel cell indicates the possibility of doubling the specific electrical output and, consequently, halving the specific CO 2 emissions, vis-à-vis conventional coke-fired power plants. Kinetic rate laws are formulated based on elementary reaction mechanisms describing reversible adsorption/desorption processes and irreversible surface chemistry. The kinetic parameters and their Arrhenius-type temperature dependence are experimentally determined using a quartz tubular reactor containing a fluidized bed of petroleum coke in steam and directly exposed to concentrated thermal radiation. Syngas containing approximately an equimolar mixture of H 2 and CO and with a relative CO 2 content of less than 5% was produced at above 1350 and 1550 K for Flexicoke and Petrozuata Delayed coke, respectively.

03/01709 Steam reforming of dodecane over supported iridium catalysts: Ando, T. et al. Journal of the Japan Petroleum Institute, 2002, 45, (6), 409–413

The steam-gasification of petroleum coke using concentrated solar radiation as the source of high-temperature process heat is proposed as a viable transition path towards solar hydrogen production. The advantages are three-fold: (1) the calorific value of the feedstock is upgraded; (2) the gaseous products are not contaminated by the byproducts of combustion; and (3) the discharge of pollutants to the environment is avoided. The thermodynamics and kinetics of the pertinent reactions are analyzed for two types of petroleum coke: Flexicoke and Petrozuata Delayed coke. The net process is endothermic by about 50% of the feedstock's LHV, and proceeds at above 1300 K to produce, in equilibrium, an equimolar mixture of H2 and CO. A Second-Law analysis on the processing of this syngas to H2 (by water–gas shift followed by H2/CO2 separation) for power generation in a fuel cell indicates the possibility of doubling the specific electrical output and, consequently, halving the specific CO2 emissions, vis-à-vis conventional coke-fired power plants. Kinetic rate laws are formulated based on elementary reaction mechanisms describing reversible adsorption/desorption processes and irreversible surface chemistry. The kinetic parameters and their Arrhenius-type temperature dependence are experimentally determined using a quartz tubular reactor containing a fluidized bed of petroleum coke in steam and directly exposed to concentrated thermal radiation. Syngas containing approximately an equimolar mixture of H2 and CO and with a relative CO2 content of less than 5% was produced at above 1350 and 1550 K for Flexicoke and Petrozuata Delayed coke, respectively.

Studies in catalytic steam gasification of petroleum coke with special reference to the effect of particle size

The object of this work is to study the effect of particle size, porosity, and thickness of a pellet on the gasification of very low ash (<0.5%) petroleum coke with steam both in the presence and absence of catalyst. Isothermal runs were carried out in the temperature range 695-880/sup 0/C using different sizes of particles (0.037-0.59 mm) and also different thicknesses of flat plates (0-7 mm) prepared from these particles. The experimental results showed some unusual behavior. The rate constant was observed to increase with an increase in particle size as well as with a decrease in thickness of the flat plates.