The direct deoxygenation effect of CaO on bio-oil during biomass pyrolysis in a fluidized-bed reactor was studied. Bio-oils were produced from white pine in the presence and absence of CaO at 520 °C and a carrier gas flow rate of 50 L/min (standard temperature and pressure). The results showed that the oxygen content of the organic components in the bio-oils was 39, 39, 39, 36, 32, and 31 wt % for white pine alone and white pine accompanied with CaO at CaO/biomass mass ratios of 1, 2, 3, 4 and 5, respectively. At a CaO mass ratio of 5, the relative reduction of oxygen content in the bio-oil reached 21%. Detailed gas chromatography−mass spectrometry analysis showed that the relative abundances of high oxygen content laevoglucose, formic acid, and acetic acid were highly reduced by CaO, indicating direct fixation of “the active quasi-CO2 intermediates” produced during biomass pyrolysis. Furthermore, the relative abundances of furfural, furfuryl alcohol, etc., mainly derived from dehydration reactions, all increased, showing that CaO addition could also catalyze dehydration reactions. X-ray diffraction and Fourier transform infrared analyses of the solid residues prepared by a thermal balance confirmed the direct fixation of the active quasi-CO2 intermediates and showed that some organic calcium salts appeared at 350 °C, which would decompose below 400 °C to form easily regenerated CaCO3. This further confirmed the feasibility of CaO recycling for in situ deoxygenation of bio-oil.

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Experiments were carried out in a multipath air inlet one-dimensional furnace to assess NO x emission characteristics of the staged combustion of anthracite coal. These experiments allowed us to study the impact of pulverized coal fineness and burnout air position on emission under both deep and shallow air-staged combustion conditions. We also studied the impact of char-nitrogen release on both the burning-out process of the pulverized coal and the corresponding carbon content in fly ash. We found that air-staged combustion affects a pronounced reduction in NO x emissions from the combustion of anthracite coal. The more the air is staged, the more NO x emission is reduced. In shallow air-staged combustion (f M ) 0.85), the fineness of the pulverized coal strongly influences emissions, and finer coals result in lower emissions. Meanwhile, the burnout air position has only a weak effect. In the deep air-staged combustion (f M ) 0.6), the effect of coal fineness is smaller, and the burnout air position has a stronger effect. When the primary combustion air is stable, NO x emissions increase with increasing burnout air. This proves that, in the burnout zone, coal char is responsible for the discharge of fuel-nitrogen that is oxidized to NO x . The measurement of secondary air staging in a burnout zone can help inhibit the oxidization of NO caused by nitrogen release. Air-staged combustion has little effect on the burnout of anthracite coal, which proves to be suitable for air-staged combustion.

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Catalytic upgrading of biomass-based aldehydes into chain-extended intermediates for downstream applications in biofuels, fine chemicals, and renewable materials, is reviewed.

The advantages and disadvantages of the typical semidry flue gas desulfurization (FGD) processes are analyzed, and a novel semidry FGD process with multifluid alkaline spray generator is first proposed to improve the colliding contact efficiency between sorbent particles and spray water droplets, and to form a large amount of aqueous lime slurry. The experimental results show that the colliding contact efficiency between lime particles and water droplets in the prefix alkaline spray generator may reach about 70%, which is significantly higher than the colliding contact efficiency of 25% in duct sorbent injection. The SO2 removal efficiency can reach 64.5% when the Ca/S molar ratio is 1.5, the approach to the saturation temperature is 10.3 °C, and the flue gas residence time is 2.25 s. It is higher than that of in-duct sorbent injection under similar conditions, and the sorbent utilization is improved to 43%. Therefore, the FGD process with a prefix alkaline spray generator can greatly improve SO2 removal efficiency and sorbent utilization and it will be a new, simple and efficient semidry FGD process for industrial application in the future.

The performance of an intermittently aerated sequencing batch reactor (IASBR) technology was investigated in achieving partial nitrification, organic matter removal and nitrogen removal from separated digestate liquid after anaerobic digestion of pig manure. The wastewater had chemical oxygen demand (COD) concentrations of 11,540 ± 860 mg/L, 5-day biochemical oxygen demand (BOD(5)) concentrations of 2,900 ± 200 mg/L and total nitrogen (TN) concentrations of 4,041 ± 59 mg/L, with low COD:N ratios (2.9) and BOD(5):COD ratios (0.25). Synthetic wastewater, simulating the separated digestate liquid with similar COD and nitrogen concentrations but BOD(5) of 11,500 ± 100 mg/L, was also treated using the IASBR technology. At a mean organic loading rate of 1.15 kg COD/(m(3) d) and a nitrogen loading rate of 0.38 kg N/(m(3) d), the COD removal efficiency was 89.8% in the IASBR (IASBR-1) treating digestate liquid and 99% in the IASBR (IASBR-2) treating synthetic wastewater. The IASBR-1 effluent COD was mainly due to inert organic matter and can be further reduced to less than 40 mg/L through coagulation. The partial nitrification efficiency of 71-79% was achieved in the two IASBRs and one cause for the stable long-term partial nitrification was the intermittent aeration strategy. Nitrogen removal efficiencies were 76.5 and 97% in IASBR-1 and IASBR-2, respectively. The high nitrogen removal efficiencies show that the IASBR technology is a promising technology for nitrogen removal from low COD:N ratio wastewaters. The nitrogen balance analysis shows that 59.4 and 74.3% of nitrogen removed was via heterotrophic denitrification in the non-aeration periods in IASBR-1 and IASBR-2, respectively.

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