Giulia Santunionea, Alessandro Bigib, Marco Pugliaa, Nicolò Morsellia, Lorenzo

Sebastianellia, Paolo Tartarinia

aBEELab (Bio Energy Efficiency Laboratory), Department of Engineering “Enzo Ferrari”, bLARMA (Labortorio di Analisi, Rilevamento e Monitoraggio Ambientale), Department of Engineering “Enzo Ferrari”

University of Modena and Reggio Emilia, Via Vivarelli 10/1 – 41125 Modena, Italy.

STUDY OF COPPER CONTENT DISTRIBUTION THROUGH THE

THERMOCHEMICAL CONVERSION CHAIN OF VINE PRUNING BIOMASS

INTRODUCTIONViticulture represents the main agriculture activity in Italy, with the 20% of the

total European wine production. The main problem related with vine cultivation

is represented by the use of large amounts of Cu-based fungicide. Copper

toxicity involves the complete production chain around viticulture, including

the quality of agriculture waste and their emissions when wastes are used as

fuel in power plants.

In a circular economy view, vineyard pruning residues (Fig. 1)can be exploited

as a convenient fuel, through several technologies capable of converting

organic biomass into energy efficiently. Among these, there is gasification, the

thermal decomposition of the biomass into a fuel gas (syngas) through under-

stoichiometric reactions. Gasification of lingo-cellulosic biomass produces

sustainable energy as well as a valuable by-product known as biochar.

Biochar is a carbonaceous material with soil amendment properties. The

feasibility of using biochar as soil amendment depends on its elemental

composition, which depends in turn on the kind of biomass involved in

gasification.

AIM OF THE STUDYTo investigate the copper content distribution throughout the thermochemical

conversion of vineyard pruning residues, analyzing Cu-traceability into biomasspellets, biochar ad gasifier emissions (Fig. 2a,b,d).

Figure 1: Tipical vineyard for «Grasparossa» wine production in Emilia Romagna

region.

Figure 3: Biochar view through Scanning

Electronic Microscope image: micropres

(Ø< 2 μm) and

mesopores (<2 Ø <50 μm) are visible (250x

magnification)

Figure 2:

Thermochemic

al conversion of

pellets (a) to

biochar (b)

through ALL

Power Labs

Power Pallet

PP30 (c). Filters

were handled

according to

UNI EN 13284-1,

2003 (d).

(a)

(b)

(c)

(d)

MATERIALS AND METHODSA semi quantitative analysis on vineyards pellets have been performed in order

to check a possible copper traces. X-Ray Fluorescence spectroscopy was

used to analyze “Grasparossa” pellets.

Cu traces have been measured into pellets through Inductively Coupled

Plasma - optical emission spectroscopy (ICP-OES).Three samples have been incinerated according to the UNI EN

14775:2010 (550° for 4 hours) to get the ashes. The copper extraction from

biomass ashes have been made using 50 ml of 65% HNO3 ultrapure.

The digestion of samples run at 100°C during 10 days. Then, the samples

have been filtered on Whatman blue strain filters.

It is obtained from gasification process of traditional viticulture pruning,

using a ALL Power Labs PP30 (Fig. 2d). The average temperatures

recorded in the run were: 819°C for char reduction starting point and

656 °C for reduction ending point. Biochar production run was

performed with an average electrical load of 13.75 kW applied to the

generator. The nominal consumption of the system was 1.09 kg/kWh

on dry basis, and the nominal biochar production is 10% in weight of dry

biomass. Biochar have been analyzed through Inductively Coupled

Plasma Mass Spectrometry (ICP-MS) which guarantees a higher

sensitivity. Electronic Scanning Microscope image of biochar is shown in

Fig.3.

Particulate emissions were directly sampled at the stack exit: the sampling

device combined a stainless steel probe, a custom-built silica-gel diffusion

dryer, a 47 mm stainless steel inline filter holder (Pall Corporation) and a

diaphragm vacuum pump (Vacuubrand MZ2-NT). The emissions were

sampled on 47 mm quartz fiber filters (QMA grade, Whatman) for 15

minutes with a flow rate ranging between 25 and 15 l min-1 depending on

the sample. 7 samples were collected and for all the mass of emitted

particles was assessed. 3 samples were also extracted and analyzed by

ICP-MS for the estimate of the Cu content.

PelletB

ioch

arEm

ission

RESULTSConsidering that for every kg of dry wood biomass, the All Power Labs gasifier is

designed to generate 0.8–0.9 kWh of electrical energy, copper amount in 1 kg

of biochar is expected to be ten times higher than the amount measured in the

pellets. The results confirm an average Cu-content of 92.96 mg/kg in the

biochar compared with 9.67 mg/kg in the starting biomass. Per each kg of

dried biomass which entered into the Power Pallet, 0.131 mg of copper were

emitted into the atmosphere (Fig.4).

Figure 4: Mean Copper content in samples of particulate emissions, biochar and

pellets. The values are expressed in mg/kg of starting mass and they represent the

average values of 3 samples (P1, P2, P3 for Pellet, B1, B2, B3 for Biochar, F1, F2, F3

for Emission).

CONCLUSIONSThe use of copper-based fertilizer is necessary to cope with a common

viticulture pathological fungus, Plasmopara viticola. For this reason, Italy and

Europe provide a strict regulation about the use of any type of fertilizers in order

to avoid the danger of contamination of vineyard soil, grapes and biomass. This

study gives preliminary data on the traceability of copper along

thermochemical conversion of vineyard pruning. In particular, this work proved

that the main part of copper contained into lingo-cellulosic biomass remains

inside the biochar. Nevertheless, each sample of biochar analyzed and the

average value of the Cu-content largely stay within the limits defined by D.Lgs.

n. 75/2010 regarding soil amendments. Similarly, total particulate coming out

from the exhausted pipe respects the limits drawn by the EuropeanEnvironmental Agency.

ACKNOWLEDGEMENTSThe authors would like to thank Ohad Zivan for his contribution during emissions

sampling test; Chemestry Laboratory LADAC and CIGS (Centro

Interdipartimentale Grandi Strumenti) from University of Modena and Reggio

Emilia for their fundamental support during ICP analysis. The study was realized

with the support of “Programma regionale di sviluppo rurale 2014-2020 – Tipo di

operazione 16.1.01 – Gruppi operativi del partenariato europeo per

l’innovazione: “produttività e sostenibilità dell’agricoltura”. Focus Area 5C –Progetto “Valorizzazione dei sottoprodotti della filiera vitivinicola - Val.So.Vitis»

Contact: Giulia Santunione: giulia.santunione@unimore.it