Fates of nutrient elements and heavy metals during thermal conversion of cattle slurry-derived anaerobic digestates  

作　　者：Daniel J.Lane Olli Sippula Jorma Jokiniemi Mikko Heimonen Niko M.Kinnunen Perttu Virkajärvi Narasinha Shurpali 

机构地区：[1]Commonwealth Scientific and Industrial Research Organization(CSIRO),Queensland Centre for Advanced Technologies(QCAT),1 Technology Court,PO Box 883,Pullenvale,Kenmore,QLD 4069,Australia [2]Department of Chemistry,University of Eastern Finland,Joensuu FI-80130,Finland [3]Department of Environmental and Biological Sciences,University of Eastern Finland,P.O.Box 1627,Kuopio FI-70211,Finland [4]Production Systems Unit,Grasslands and Sustainable Agriculture Group,Natural Resources Institute Finland(Luke),Maaninka FI-71750,Finland

出　　处：《Bioresources and Bioprocessing》2024年第1期1515-1527,共13页生物资源与生物加工(英文)

基　　金：financially supported by the Research Council of Finland grant to NJS(grant#311970);the Finnish Ministry of Agriculture and Forestry(VN/28562/2020-MMM-2).

摘　　要：Thermal processes are emerging as promising solutions to recovering phosphorus and other nutrient elements from anaerobic digestates.The feasibility of nutrient element recovery depends largely on the fates of nutrient elements and heavy metals during thermal processing.This study assesses the partitioning of macronutrients(N,P,K,Na,Ca and Mg)and heavy metals(Zn,Cu,and Mn)between condensed and gaseous phases during thermal conversion of cattle slurry digestates in gas atmospheres of pyrolysis,combustion,and gasification processes.This study also assesses the chemical forms of macronutrients retained in combustion ashes.The partitioning of elements between condensed and gaseous phases was quantified by mass balances based on elemental analyses of char and ash residues.The char and ash residues were prepared in a fixed-bed,batch reactor at temperatures within the range 800-1000°C.Powder X-ray diffraction was used to identify the chemical forms of macronutrient elements in combustion ashes.Volatilisation of P was low(<20%)when the digestates were heated in inert and oxidising atmospheres,whereas a reducing atmosphere volatilized P to a major extent(~60%at 1000°C).Oxidising atmospheres increased volatilisation of N but suppressed volatilisation of K,Na,and Zn.Volatilisation of the following elements was low(<30%)in all investigated operating conditions:Ca,Mg,Mn,and Cu.The combustion ashes contained both high concentrations of P(around 7 w/w%)and acceptable concentrations of regulated heavy metals(Cu,and Zn)for application on agricultural and forest soils in Finland.Phosphorous was retained in the combustion ashes in the form of whitlockite.This form of P is expected to be available to plants when the ashes are added to soil.

关 键 词：Ash utilization Combustion GASIFICATION PYROLYSIS Phosphorous recovery VOLATILIZATION BIOCHAR 

分 类 号：TG1[金属学及工艺—金属学]