Table 3 Studies on slow, rapid, microwave-assisted, co-pyrolysis of DGS
From: A review on the thermochemical reaction mechanisms for distiller pyrolysis process
Feedstock | Catalyst | Reactor | Experimental details | Key Results | Ref |
|---|---|---|---|---|---|
Slow pyrolysis | |||||
 DGS | None | Fixed bed | Mass: 3 g Reaction temperature and pressure: 400, 500, 600 °C and 100, 500, 1000 kPa Carrier and flow rate: N2 | The main component of bio-oil was fatty acid, and its yield decreased with the increase of pressure. At 500 °C and 100 kPa, the maximum yield was 36.4% | [11] |
 Rice husk DGS | None | TG analyzer | Mass: 10 ± 0.1 mg Reaction temperature and heating rate: 50–1000 °C and 10 °C min−1 Carrier gas: 60 mL-N2 min−1 | The mass loss of RHDG of ~ 44% occurred at 250–400 °C. The volatiles released from pyrolysis had more diesel range organic compounds and H/C, O/C ratios. The activation energy of pyrolysis was ~ 240 kJ mol−1 | [23] |
 DGS | None | TG analyzer | Reaction temperature and heating rate: final temperature of 900 °C and 5, 10, 20, 30, 100 °C min−1 Carrier gas: 100 mL-He min−1 | The TG curve showed three main peaks at 280, 330 and 402 °C with a total weight loss of around 79%. NH3 was the main N-compound released at low temperatures with a peak at 319 °C | [29] |
 DGS | None | TG analyzer | Mass: 5 ± 0.2 mg Reaction temperature and heating rate: 50–900 °C and 10, 20, 30, and 40 °C min−1, the temperature rose from 50–900 °C Carrier gas: 150 mL-N2 min−1 | The total mass loss was about 72%. Lignocellulose components such as protein and amino acid can promote the decomposition of DGS | [30] |
 Barley DGS | None | TG analyzer | Mass: 4.5 mg Reaction temperature and heating rate: final temperature of 773 and 900 K and 5, 10, 20 K min−1 Carrier gas: N2 and air | DGS pyrolysis in air and nitrogen was similar, but oxidation environment would enhance degradation and reduced Ea. Degradation of multi-components in DGS and the catalysis of alkali compounds also reduced the activation energy | [27] |
 DGS | None | TG analyzer | Mass: 45% moisture of wet basis Reaction temperature and heating rate: final temperature of 650 °C, 850 °C and 10, 30, 50 °C min−1 Carrier gas: N2 and air | The starting temperatures increased with the increase of heating rate and initial moisture content. The residual weights of DGS after oxidation in air were only 5.49% of the original dry mass | [37] |
 Moutai DGS | None | TG analyzer | Mass:5 mg Reaction temperature and heating rate: final temperature of 1223 K and 10, 20, 30, 40 K min−1 Carrier gas: 20 mL-N2 min−1 | The effective activation energies of DDGs pyrolysis significantly varied with conversion (from 151.2 to 320.5 kJ mol−1 with the conversion range of 0.05–0.95) | [5] |
 Corn DGS | Zeolite | Microscale reactor | Mass: Catalyst mixed with DGS in a ratio of 20:1 with total mass of 5 mg Reaction temperature: 400, 500, 600, and 700 °C Carrier gas: 90 mL-He | Protein and lipid might enhance yield of aromatics and olefins. The highest carbon yields of aromatics and olefins (44.5 and 12.3%, respectively) occurred for a SiO2/Al2O3 ratio of 30 at 600 °C | [38] |
 DGS | Ni–Al-MCM-41/(Me)-γ-Al2O3 | Fixed bed | Mass: 5 g mixed with 5 mg catalyst Heating rate: 20 K min−1 for 1.5 h Carrier gas: 70 mL-N2 min−1 | The average HHV of the bio-oil was 25,739 kJ/kg, which was about 61% of that of gasoline. Catalyst can promote the production of H2, specially for Ni–Pd-γ-Al2O3, the volume percentage in pyrolysis gas reached to 55.6 vol.% | [39] |
Fast pyrolysis | |||||
 DGS | None | Heated foil reactor | Mass: 5–7 mg Heating rate: final temperature of 500–1300 °C and 600 °C min−1 Carrier gas: He | At 1,300 K, the final mass loss was 92wt%. High heating rate can change the protein decomposition mechanism from deamination to dehydration and promote the tar-N decomposition. CO was dominant at temperatures higher than 1,000 °C with increasing gaseous product | [40] |
 Barley DGS | None | Fluidized bed | Reaction temperature: ∼500 °C | The potential yield of GS organic bio-oil was 48wt%. Bio-oil from DDGS had a very high energy content, ∼80% of petroleum (dry basis) and was nearly pH-neutral, but will be more heterogeneous and viscous with time | [41] |
 DGS | CaO | Fixed bed | Reaction temperature: 490, 530, 570 °C Carrier gas: N2 | The oil composition was simple. When CaO was added to pyrolysis at 570 °C, more aliphatic and aromatic hydrocarbons were generated, and content of phenols was increased, while fatty acids and their esters was reduced | [18] |
Microwave-assisted pyrolysis | |||||
 DGS | None | Microwave oven | Mass: 100 g Heating rate: 105, 130, 255, 500, and 570 °C min−1 at the power inputs of 600, 700, 800, 900, and 1000 W Carrier gas: N2 | The highest heating value of DDGS bio-oil was obtained at the 650 °C and 8 min, which was about 66.7% of the heating value of gasoline | [42] |
Co-pyrolysis | |||||
 Oil-based drill cuttings + DGS | None | Fixed bed | Mass ratio of DGS: 10:0, 8:2, 7:3, 5:5, 3:7, 2:8, and 0:10 Reaction time: 250–500 °C | OBDC promoted the pyrolysis of DGS. Mass ratio of OBDC: DGS at 7:3, holding temperature at 350 °C, holding time for 60 min and heating rate at 10 °C min−1 | [43] |
 Waste plastic mulching films + DGS | ZSM-5/MCM-41 | Microwave reactor | Mass: ~ 10 g Mass ratio of DGS: 0.25, 0.5, 1, 2 Reaction time: ~ 750 °C | Higher W/D ratio can promote bio-oil production and retard coke formation and synergy existed between them. Catalyst increased hydrocarbon yield in bio-oil | [44] |