Chemical Characteristics of Biomass Ashes Zając, Grzegorz; Szyszlak-Bargłowicz, Joanna; Gołębiowski, Wojciech ...
Energies (Basel),
11/2018, Volume:
11, Issue:
11
Journal Article
Peer reviewed
Open access
The aim of the conducted research was to obtain information on the main components of ashes from 35 biomass species used in combustion processes to obtain reference data for the development of ...utility possibilities for these ashes, with particular emphasis on agricultural use. The examined biomass samples were divided into groups depending on origin: woody biomass and energetic woody plants I-WWB, herbaceous and grassy energy plants II-EC, agricultural waste III-AR, forest waste IV-FR and waste from the agri-food industry V-AFIW. The analysis of the studied elements contents was carried out in the designated groups. The chemical composition of ash was dominated by the macroelements Ca, K, P and S, which suggests the possibility of their agricultural use. At the same time, the low content of toxic elements such as As and Pb should not be a limiting feature in their use, with the exception of wood biomass. In addition, ashes obtained from the biomass combustion were enriched with microelements such as Zn, Cu and Mn, which further increases their possibilities of fertilizer use. The potential use of ash from each type of biomass in the aspect of its chemical composition should be considered individually, regardless of the division into groups depending on the origin of biomass.
The rapid expansion of biomass power generation has resulted in a large amount of ash, which need to be treated urgently. The trace elements in ash also have environmental risks during treatment. ...Therefore, the essential characteristics and potential environmental risks of biomass ash generated by direct combustion of agricultural straw were studied. The leaching characteristics of elements, including major elements (Mg, K, Ca) and trace elements (V, Cr, Mn, Co, Ni, Cu, Zn, Cd, As, Pb and Ba), in fly ash and slag produced by biomass power plant were analyzed through the static leaching experiments of simulating the possible pH value of natural water in the laboratory. The results show that the trace elements are enriched in fly ash and slag, which may be related to the volatility of elements during combustion. And during the leaching test, the leaching concentration of major and trace elements in fly ash is higher than that in slag. Sequential chemical extraction is used to reveal the occurrence forms of trace elements in biomass ash. Except for residue, Mn, Co, Zn, Cd, and Pb in fly ash mainly exist in carbonate bound, V and As are Fe–Mn oxides bound, and Cr, Ni, Cu, and Ba are mainly organic matter bound. In the slag, Cd is mainly carbonate bound, Cu is mainly organic matter bound, while other elements are mainly Fe–Mn oxides bound. The Risk Assessment Code values calculated based on the existing forms of elements show that As and Cd in slag and Mn, Co, Pb and Cd in fly ash need special attention during utilization. The research results can provide reference for the management and utilization of biomass ash.
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•The toxic leaching concentration of biomass ash is lower than the standard limit.•The major elements and trace elements in biomass ash show different leaching laws.•There are different occurrence forms of elements in biomass ash.•Mn, Co, Cd, Pb in fly ash and As, Cd in slag have potential environmental risks.
Use of biomass for energy production is increasing, so management of the resultant ash is important. This review compares current and future production, chemical composition, and reuse options for ...ash from common feedstocks (agricultural residues, energy crops, woody biomass, forest residues, recovered wood, paper sludge, sewage sludge and municipal solid waste). Global production is ~170 Mt/yr, but could increase to ~1000 Mt/yr if all available biomass were exploited. Current production is dominated wood and waste derived ashes, but there is capacity to greatly increase use of agricultural residues. Combustion of virgin biomass in modern furnaces can produce ash with negligible persistent organic pollutants and low contaminant metals concentrations, so application to land is possible. Agricultural residue ashes contain abundant potassium and useful phosphate, so could potentially be used as fertiliser. Forestry ashes are rich in CaO, but slightly higher contaminant metals levels may restrict their use to forestry soils. Recovery of potassium from these ashes, and their use in cementitious materials have also been demonstrated. Biomass containing waste ashes potentially contain more persistent organic pollutants and contaminant metals. However, municipal solid waste bottom ash is routinely used as a construction aggregate for prescribed applications. Paper sludge ash is suitable for restricted use as a soil conditioner and possibly as a secondary pozzolan. However, controlled disposal may be required for recovered wood ash and sewage sludge incineration ash. As persistent organic pollutants tend to partition to the flue gases, fly ash and air-pollution control residues are likely to require controlled disposal.
•Current global production of biomass ash is ~170 Mt/yr.•Production could be 1000 Mt/yr with greater use of agricultural residues and wastes.•Burning virgin biomass in a modern furnace gives ash suitable for application to land.•Burning biomass waste gives ash with potentially problematic contaminant levels.•Pollutants in flue gases mean fly ash and similar residues need controlled disposal.
The main part of companies in Bulgaria are built, however in the 70s, and upgraded last decade. The countrysupplies around 80 % of its supplies of paper, paperboard and pulp with own production. ...Integrated treatment ofwastes is a priority for realizing closed life cycle of materials. The aim of the present work is to investigate thecomposition and other important characteristics of biomass wood ash wasted from paper industry. The correlationsand associations among the chemical characteristics are also studied to find some basic trends and importantrelationships between two similar wastes from different enterprises. It was proved that all samples taken containedBa, Cr, Mn, Ni, Co, Al, Fe, Cu and Zn far below the legal limits for such type of products. A product has a certain anti-acidic effect. The other positive result was that the content of iron is between 34 to 60 mg per 1 kg dry waste. The microscopic photos confirmed that the particles are close to the nano-size materials. The content of the elements C, N, H is in good quantities and ratios, which is a prerequisite for their use as a soil improver. By the results of this study, it was confirmed that all samples produced as a result of the thermal treatment and final low water content achieved are free from pathogen microorganisms and different weed seeds, affecting the yield and soil sustainability. That allows determining the optimal ratio between the used components with a view to obtain products with desired thermal stability and physico-chemical properties as soil improvers.
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•Amines significantly improved the CO2 sequestration capacity of ashes.•Amines enhanced Ca2+ leaching from alkaline ashes.•The phytotoxicity of alkaline ashes were significantly ...reduced after carbonation.
Amine-looping-based CO2 mineralization is a promising technology for simultaneous CO2 absorption, mineralization, and carbonate crystallization in a single step. This paper performed a detailed investigation of the feasibility and underlying mechanism of the amine-looping process using industrial alkaline solid wastes, including one Biomass ash (BA) and two coal-fired fly ashes named FA1 and FA2. The CO2 sequestration capacity and CO2 removal efficiency of selected ashes were investigated in five typical amine solutions, including monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), 2-amino-2-methy-1-propanol (AMP), and piperazine (PZ). The physicochemical property of ashes before and after carbonation and the dissolution of alkaline minerals in various amine solutions were systematically determined to explore the underlying mechanism involved in the amine-looping process. Results show that greater improvement in CO2 removal efficiencies and CO2 sequestration capacities were obtained by selected ashes in amine solutions compared to the traditional CO2 mineralization in the water-ash-CO2 system. It also revealed that amines played important roles in promoting CO2 mass transfer, enhancing Ca2+ leaching, and producing small-sized CaCO3. The largest CO2 sequestration capacity (102.9 g/kg) was achieved by FA1 in PZ solution which was suggested as the preferred solvent for the amine-looping process. In addition, the environmental risk of carbonated ashes for agricultural application in terms of amine loss and phytotoxicity was evaluated. Results implied that the phytotoxicity of carbonated BA could be neglected when a simple centrifugal wash was used to remove the absorbed amine on the surface of carbonated BA whilst the phytotoxicity of selected ashes can be significantly reduced after carbonation reactions.
The objective of this study was to enrich the nutrient content of compost and to investigate the passivation and solubilization of plant micronutrients (Fe, Al, Cu, Ni, Zn, Na, Mn), macroelements (P, ...K, Mg, Ca), and heavy metals (Cr, Cd, Pb) during sewage sludge composting with nutrient-rich biomass ash additives. T0: 0%, T1: 3.5%, T2: 7.0%, and T3: 14.0% dry weight (DW), weight/weight (w/w) biomass ash was added to the sewage sludge + sawdust mixture (volume, 1:1) to obtain the final NPK content and monitored over a 45-day period. Sawdust was used as auxiliary material. The sequential extraction method was used to determine the elemental species. Cr, Cd and Pb showed higher affinity to the residual fraction and occluded in the oxide fraction, which decreased the bioavailability factor (BF) (<1% BF–Cr, 21% BF–Cd and 9% BF–Pb) compared to the control treatment (46% BF–Cr, 47% BF–Cd and 80% BF–Pb). As the amount of biomass ash increased (T1-T3), the percentages of residual Cr (Res-Cr) (10–65%), exchangeable Cd (Exc-Cd) and organically bound Cd (Org-Cd) (14% and 21%), and oxides-Pb (Oxi-Pb) (20–61%) increased. In all composts, Fe, Al, and Cu were associated with organically bound and oxides-entrapped fractions. More than 50% of total Mn and Mg were concentrated mainly in exchangeable fractions, suggesting high mobility and bioavailability (42% BF–Mn and 98% BF–Mg). Ni, Zn, and Na tended to be present in oxide-bound, organically bound, and residual fractions, while K and P were associated with exchangeable and organically bound fractions. The overall results suggest that composting sewage sludge with biomass ash may be the best strategy and technique to overcome soil application bottlenecks because it passivates heavy metals and improves the bioavailability of plant nutrients.
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•Biomass ash effect on the speciation of micro-macro elements was investigated.•Biomass ash effect on the passivation of heavy metals was researched.•Biomass ash addition reduced the bioavailability of all elements except Mn and Mg.•Mn and Mg were concentrated in exchangeable fractions (41% and 48%, respectively).•Biomass ash has a high effect on reducing the bioavailability of heavy metals (<1% BF–Cr, 21% BF–Cd, 9% BF–Pb).
•Ash yields of numerous biomass varieties were characterized.•Contents of 12 ash-forming elements in numerous biomass varieties were studied.•Challenges related to ash of biomass for biofuel ...application were described.
Inorganic matter and some ash-forming elements of biomass may cause numerous technological and environmental problems during biomass processing. Therefore, an extended overview of the ash contents and ash-forming elements of biomass and their significance for solid biofuel combustion was conducted based on reference peer-reviewed data plus own investigations. Initially, some general considerations such as current bioenergy situation and different aspects related to biomass use as biofuels, as well as some common issues concerning the main advantages and disadvantages of ash contents and ash-forming elements of biomass are discussed. Then, definition, specification, terminology clarification and composition related to inorganic and mineral matter of biomass and biomass ash (BA) are considered. Further, the contents and concentration/depletion trends of ash (for 532 biomass varieties) and 12 ash-forming elements based on traditional and complete ash analysis of Si, Ca, K, P, Al, Mg, Fe, S, Na and Ti oxides (141 BA varieties) plus elemental Cl (87 BA varieties) and Mn (156 BA varieties) were characterized. The correlations and associations among the ash yields and contents of ash-forming elements of natural biomass (127 biomass and BA varieties) were also identified using the present database. Finally, the origin and significance of ash-forming elements and their associations established in biomass, namely (1) Si – Al – Fe – Ti; (2) Ca – Mg – Mn; and (3) K – P – S – Cl – Na were described and the benefits and obstacles of these associations for biofuel combustion were evaluated. It was found that the high ash yields and contents of some ash-forming elements such as Cl, K, Na, P, S and some other elements with unfavorable modes of element occurrences (chlorides, sulphates, carbonates, oxalates, nitrates and some oxyhydroxides, phosphates and amorphous material) in biomass and BA may provoke the most critical technological and environmental challenges during biomass processing and especially during biomass thermochemical conversion.
Chemical, physical, mineralogical and radiological characterization of olive biomass fly ash (OBFA) and bottom ash (OBBA) was main objective to determine their potential use as alkaline activators in ...the preparation of alkali-activated materials or geopolymers. Water solubility tests showed that they released K and Na ions, affording a high pH and alkaline content.
Pastes made with 70 wt% vitreous blast furnace slag (SL) and 30 wt% of OBFA or OBBA yielded alkali-activated materials with 28 days mechanical strength of 33 to 18 MPa. In pastes prepared with 30 wt% OBFA, strength values were comparable to those developed by slag pastes activated with a commercial KOH. However, the pastes made with 70 wt% coal fly ash and 30 wt% OBFA or OBBA proved to be inviable because the pH reached was not high enough to activate the precursor.
The radiological calculations of OBFA- and OBBA-SL bearing pastes would conform to European legislation on protection against exposure to ionising radiation, for the activity concentration index (ACI) found in the final product was less than 1 in all cases. The pastes leached primarily K. The presence of elements such as 210Po and 210 Pb at the end of the decay chain in the eluates would not limit the use of biomass ash and slag blends.
These findings have confirmed the feasibility of using olive oil biomass ashes as an alternative alkaline activator in blast furnace slag systems to produce alkali-activated materials or geopolymers, with properties that make them apt for use as building materials.
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