Biomass Combustion: Evaluation of POPs Emissions (VOC, PAH, PCB, PCDD/F) from Three Different Biomass Prunings (Olive, Citrus and Grapevine)

Abstract

Agricultural activities lead to the production of large quantities of pruning and residual biomass, the correct disposal of which is a topic of great interest. Unfortunately, although it is an environmentally unacceptable practice, disposal often takes place with uncontrolled combustion in field (open burning). Disposal using biomass boilers produces energy from controlled combustion and the use of abatement systems reduces emissions that are inevitably generated in the combustion processes of solid fuel (CO, CO2, NOx, SO2, PM, etc.). Among the pollutants produced in combustion processes, Persistent Organic Pollutants (POPs) are one of the most relevant groups of chemicals that must be monitored for their effect on human health and the environment. This paper reports the data obtained for the emissive characterization of POPs of three different wood biomass prunings (Olive, Citrus and Grapevine) focusing on VOCs, PAHs, PCBs, PCDD/Fs. Emissions samplings were performed at the stack during combustion in a 30 kWth boiler equipped with a multicyclone filter bag for PM abatement in an isokinetic mode in accordance with the CEN and ISO standards methods. Through this work, a complete emission profile of VOCs, PAHs, PCBs, and PCDD/Fs of three different biomass types is provided for the first time, showing that the use of biomass boilers produces quantities of pollutants below the regulatory limits and still lower than those produced by open burning phenomena. Citrus has shown, regarding the other two essences, elevated concentrations in terms of Σ PAH = 174.247 ng/m3, while Olive gave higher results in terms of PCBs and PCDD/Fs (respectively, 39.769 and 3390.63 TEQ pg/Nm3). This is probably due to the high concentration of iron in this biomass (711.44 mg/kg), which during combustion is a catalyst (together with copper) of PCDD/Fs.

Inventory of PCDD/Fs and Fly Ash Characteristics during the e-Waste and Municipal Solid Waste Co-Incineration Process

“…However, the chlorination degrees of PCDD/Fs in BO, CH, and FA are relatively approaching in both MSWI and EWC conditions, which indicates that EWC does not have a salient influence on high/low chlorinated isomers’ generation. A possible explanation is that EW strengthens the existing PCDD/F formation than switching to high-chlorinated PCDD/Fs, in accordance with recent studies. , This phenomenon also suggests similar and linked formation pathways of PCDD/Fs.…”

Analysis of the Effect of Fe2O3 Addition in the Combustion of a Wood-Based Fuel

“…Attempts have also been made to use iron oxides together with minerals, for example, Fe 2 O 3 -coated olivine ((Mg,Fe) 2 [SiO 4 ]), as a catalyst in the gasification of biomass alone and co-gasification of biomass with coal to crack/reform tar and to increase H 2 yield [ 34 ]. The action of iron oxide and copper as a catalyst in the thermal processing of biomass is also known [ 35 ].…”