Effect of Iron Species and Calcium Hydroxide on High-Sulfur Petroleum Coke CO₂ Gasification

Abstract

The effect of iron species on petroleum coke CO2 gasification was studied in the present work. The effects of the temperature (1173–1673 K), the catalyst types, catalyst loading (ranging from 0 to 5 wt %), and composition during the gasification of petroleum coke CO2 were discussed. The catalytic gasification residue of petroleum coke was identified by X-ray diffraction (XRD). The XRD result shows that the iron species exist as Fe3C at the initial stage of gasification. Then, most Fe3C is transformed into reduced iron Fe0; subsequently, some of these species are oxidized to FeO, Fe2O3, and Fe3O4, while some of which quickly reacted with S in petroleum coke to form stable FeS, leading to catalyst deactivation. The changes during gasification are discussed in terms of the oxygen-transfer mechanism. It is clearly demonstrated that there exists a significant synergistic effect between calcium hydroxide and iron species during petroleum coke gasification. The random pore model is suitable to describe catalytic gasification of petroleum coke. The activation energy of petroleum coke CO2 gasification with 5 wt % FeCl3 is 168.06 kJ mol–1, with the temperature range of 1223–1373 K, which is 29.9 kJ mol–1 lower than pure petroleum coke CO2 gasification.

Investigating char agglomeration in blast furnace coal injection

“…A commonly used gasification figure was selected in order to indicate a char's reactivity; t 0.5 -the time in minutes taken for the chars to reach 50% conversion with a lower number signifying a more reactive char [34][35][36].…”

“…5 specific surface area runs were collected for each sample and checked for consistency with the average used as the final specific surface area result, given in m 2 /g. In order to test the impact of coal pre-heating on agglomeration, the raw coal with the strongest agglomerating tendencies was selected for [24][25][26][27][28][29][30][31][32][33][34] pre-treatment at 300°C for 60 min. This was carried out under both an inert (N 2 ) and oxidative (air) atmosphere in order to clarify whether the impacts on agglomeration are due to thermal or oxidative impacts.…”

“…Extensive agglomeration is likely to result in greater instances of char accumulation and blockages due to the increased size of agglomerated material. Increased occurrences of blockages will result in gas flow issues causing Fuel Processing Technology 178 (2018) [24][25][26][27][28][29][30][31][32][33][34] temperature and pressure build-ups, instability, and an overall reduction in furnace permeability -potentially exacerbating an already problematic issue. Although the precise form of agglomeration in the blast furnace remains uncertain, these results show that the initial heating conditions found in the hot blast region are prone to resulting in coal agglomeration.…”

“…The exceptions to this are the MV4:LV1 blends at 1:3 ratios at both particle sizes. It appears that only by blending MV4 with a particularly unreactive coal can agglomeration be eradicated, however, [24][25][26][27][28][29][30][31][32][33][34] minor blend variations can and do reduce the agglomeration effect. The blend performance of the granulated size specification is more predictable in comparison to the pulverised blends.…”

Improving slurryability, rheology, and stability of slurry fuel from blending petroleum coke with lignite

“…Owing to a continuous demand for crude oil, the production of petroleum coke in China is increasing steadily (Zhou et al 2012). Petroleum coke is a cheap fuel traditionally used as an important feedstock for circulating fluidized bed combustors because of its high calorific value, low volatile content, and high sulfur content (He et al 2011).…”