Entrained-Flow Gasification of Oil Sand Coke with Coal: Assessment of Operating Variables and Blending Ratio via Response Surface Methodology

Abstract

Co-gasification of oil sand fluid coke with sub-bituminous coal was performed in an entrained-flow gasifier. The underlying objective of this work was to assess the combined effects of the operating variables (i.e., temperature and oxygen and steam concentrations) and coal/coke blending ratio in an entrained-flow gasification process, where the focus was to quantify the relationships between the response variables and vital operating factors. With a view to the shortcomings of the classical "onefactor-at-a-time" method in identification of the effect of experimental factors and their interactions, a statistical design of the experiment based on response surface methodology (RSM) was used. The response variables used in this work were H 2 , CO, H 2 /CO ratio, gasification efficiency, and carbon conversion. Experiments were conducted over a temperature range of 1000À1400°C, using steam and oxygen to carbon weight ratios of 0.9À4.3 and 0À0.4, respectively, equivalent to 15À50 vol % steam and 0À3 vol % oxygen in N 2 carrier gas. All of the response variables were successfully fitted to either a two-factor interaction or quadratic model. Using RSM, the effects of individual operating factors and their interactions were categorically determined, which were not otherwise possible by the classical design of experiment methodology. Using the resultant response variable correlations, H 2 production was optimized as a function of the temperature, steam and oxygen concentration, and different blending ratios. The full potentiality of Canadian oil sand coke for entrained-flow gasification was successfully investigated via RSM. The results of this work, however, are only applicable to entrained-flow gasification systems.

Enriched-air fluidized bed gasification using bench and pilot scale reactors of dairy manure with sand bedding based on response surface methods

“…The high oxygen concentration also resulted in a high H 2 gas production at a lower ER m . This is because the increased oxidation reaction (C þ O 2 / CO 2 , C þ 1/2O 2 / CO) favors hydrogen production through the water-gas shift reaction [36]. The water in tar production also helps the H 2 production reactions as it was reported that a large production of tar could be produced at a low ER m condition.…”

“…The effect of the increasing temperature on the increasing H 2 composition could be explained mainly by the endothermic reactions of the water-gas reaction (C þ H 2 O 4 CO þ H 2 ) in a higher temperature [36] as well as the exothermic reactions of the water-gas shift (CO þ H 2 O 4 CO 2 þ H 2 ) and dry reforming (CH 4 þ CO 2 4 2CO þ 2H 2 ) [37]. Even though Han et al [38] reported that the effect of exothermic reactions at a higher temperature are minimal on the water-gas shift reaction, the reaction takes place and increases the ratio of H 2 to CO at up to 800 C. Heavy hydrocarbons in a high temperature favor H 2 production through the carbonization reaction (C n H m / n C þ m/2H 2 ), which lowers the tar concentration as the temperature increases [34].…”

“…It is possible that a thermal equilibrium was not closely achieved with a bench-scale gasifier as it does not have enough space and time for the further secondary reactions of syngas followed by the first oxidant reaction. In the pilot scale reactor, the produced CO 2 reacts with carbons through a Boudouard reaction to produce more CO, which help in producing hydrogen as well at a high temperature [36].…”

Pyrolysis of asphaltenes in an atmospheric entrained flow reactor: A study on char characterization

“…Pressure in the furnace is maintained slightly above 1 atm using vacuum pumps. Experiments on coal and oil sand coke have been successfully conducted earlier on the same setup with slight modifications [17,28]. Table 1 shows the operating conditions at which chars were collected.…”

“…Asphaltenes and oil sands coke have significant quantities of vanadium, nickel [United States Environmental Protection Agency (U.S. EPA) regulated elements], and sulfur that prevent their direct combustion. Integrated gasification combined cycle (IGCC) technologies are recommended for such type of fuels [16,17]. Integration of solvent deasphalting and gasification into primary upgrading has been proposed as a convenient alternative to coker based upgrading processes with operational advantages, such as easier handling of the liquid asphaltenes stream and the establishment of a continuous process.…”