Abstract
Green petroleum coke (petcoke) is used as a feedstock for raw carbon material or as a fuel. Petcoke with high sulfur (S) content (>4 wt%) is typically restricted to fuel use unless extensive S removal is successful. Here, the S removal mechanisms during both pyrolysis and combustion were explored using the Reactive Force Field (ReaxFF) MD approach. A structural representation (C1648H772O59N24S47) of a green Qingdao petcoke was generated coupling high-resolution transmission electron microscopy lattice fringe image analysis and analytical data. This structure was consistent with elemental, aromaticity (FT-IR), the pair correlation function (XRD), and functional group (S, O, and N from XPS) data. The ReaxFF pyrolysis simulation produced gas and tar yields of 44.7 and 11.0 wt% at 3000 K after 250 ps of simulation. The combustion simulation on the same initial structure was performed in an O2 environment. During the pyrolysis simulation, the first-step for S-removal was thiophenic sulfur conversion to C1–4S (mostly C2S), COS, or CNS. The heteroatom pyrolysis overlapped, for this structure, at these conditions. However, for the combustion simulation earlier conversion of thiophenic sulfur to COS was observed. No N–S containing structures occurred in this O-rich environment, as pyrrolic and pyridinic N quickly oxidized into CON or NO compounds. The S transformation during combustion can be summarized by COS → CO2S → CO3S → CO4S. The H atoms reacted with S-containing gases like COS/C2S/CNS producing HS and H2S rather than with the coke-S.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 146-157 |
| Number of pages | 12 |
| Journal | Combustion and Flame |
| Volume | 198 |
| DOIs | |
| State | Published - Dec 1 2018 |
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All Science Journal Classification (ASJC) codes
- Chemistry(all)
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology
- Physics and Astronomy(all)
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ReaxFF simulations of petroleum coke sulfur removal mechanisms during pyrolysis and combustion. / Zhong, Qifan; Mao, Qiuyun; Xiao, Jin; Van Duin, Adri; Mathews, Jonathan P.
In: Combustion and Flame, Vol. 198, 01.12.2018, p. 146-157.Research output: Contribution to journal › Article
TY - JOUR
T1 - ReaxFF simulations of petroleum coke sulfur removal mechanisms during pyrolysis and combustion
AU - Zhong, Qifan
AU - Mao, Qiuyun
AU - Xiao, Jin
AU - Van Duin, Adri
AU - Mathews, Jonathan P.
PY - 2018/12/1
Y1 - 2018/12/1
N2 - Green petroleum coke (petcoke) is used as a feedstock for raw carbon material or as a fuel. Petcoke with high sulfur (S) content (>4 wt%) is typically restricted to fuel use unless extensive S removal is successful. Here, the S removal mechanisms during both pyrolysis and combustion were explored using the Reactive Force Field (ReaxFF) MD approach. A structural representation (C1648H772O59N24S47) of a green Qingdao petcoke was generated coupling high-resolution transmission electron microscopy lattice fringe image analysis and analytical data. This structure was consistent with elemental, aromaticity (FT-IR), the pair correlation function (XRD), and functional group (S, O, and N from XPS) data. The ReaxFF pyrolysis simulation produced gas and tar yields of 44.7 and 11.0 wt% at 3000 K after 250 ps of simulation. The combustion simulation on the same initial structure was performed in an O2 environment. During the pyrolysis simulation, the first-step for S-removal was thiophenic sulfur conversion to C1–4S (mostly C2S), COS, or CNS. The heteroatom pyrolysis overlapped, for this structure, at these conditions. However, for the combustion simulation earlier conversion of thiophenic sulfur to COS was observed. No N–S containing structures occurred in this O-rich environment, as pyrrolic and pyridinic N quickly oxidized into CON or NO compounds. The S transformation during combustion can be summarized by COS → CO2S → CO3S → CO4S. The H atoms reacted with S-containing gases like COS/C2S/CNS producing HS and H2S rather than with the coke-S.
AB - Green petroleum coke (petcoke) is used as a feedstock for raw carbon material or as a fuel. Petcoke with high sulfur (S) content (>4 wt%) is typically restricted to fuel use unless extensive S removal is successful. Here, the S removal mechanisms during both pyrolysis and combustion were explored using the Reactive Force Field (ReaxFF) MD approach. A structural representation (C1648H772O59N24S47) of a green Qingdao petcoke was generated coupling high-resolution transmission electron microscopy lattice fringe image analysis and analytical data. This structure was consistent with elemental, aromaticity (FT-IR), the pair correlation function (XRD), and functional group (S, O, and N from XPS) data. The ReaxFF pyrolysis simulation produced gas and tar yields of 44.7 and 11.0 wt% at 3000 K after 250 ps of simulation. The combustion simulation on the same initial structure was performed in an O2 environment. During the pyrolysis simulation, the first-step for S-removal was thiophenic sulfur conversion to C1–4S (mostly C2S), COS, or CNS. The heteroatom pyrolysis overlapped, for this structure, at these conditions. However, for the combustion simulation earlier conversion of thiophenic sulfur to COS was observed. No N–S containing structures occurred in this O-rich environment, as pyrrolic and pyridinic N quickly oxidized into CON or NO compounds. The S transformation during combustion can be summarized by COS → CO2S → CO3S → CO4S. The H atoms reacted with S-containing gases like COS/C2S/CNS producing HS and H2S rather than with the coke-S.
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U2 - 10.1016/j.combustflame.2018.09.005
DO - 10.1016/j.combustflame.2018.09.005
M3 - Article
AN - SCOPUS:85053781528
VL - 198
SP - 146
EP - 157
JO - Combustion and Flame
JF - Combustion and Flame
SN - 0010-2180
ER -