Removal Of Inorganic Elements Research Articles

Bioleaching to produce clean loblolly pine for thermochemical conversion

Lignocellulosic biomass contains inorganic elements that could induce slagging, ash fouling, and emission of both corrosive and harmful gases during thermochemical conversion. Water leaching pretreatment can remove most of the water-soluble elements, while it has limited industrial applicability due to its ineffectiveness in removing water-insoluble elements. Bioleaching is an alternative pretreatment method which has not been fully studied. In this work, bioleaching by Aspergillus niger strains NRRL 2001, NRRL 3122, and NRRL 567 was conducted to pretreat loblolly pine biomass with added water. The removal of inorganic elements (K, Ca, Mg, and S) by bioleaching with A. niger NRRL 2001 was compared with chemical leaching with citric acid, HCl, and NaOH. It was shown that the pH reduction during bioleaching greatly improved K and Mg leaching to the point comparable to acid leaching, whereas Ca was precipitated by oxalic acid produced by the fungus. Bioleaching was also conducted in manually separated needles and chips components of loblolly pine. Glucose was added at different levels to assist bioleaching. At higher glucose levels, gluconic acid and citric acid were produced during bioleaching, leading to the increase of K, Ca, and Mg removal rates by more than 35%, 180%, and 390%, respectively, from the feedstock as compared with water leaching. Overall, bioleaching greatly improved removal of K, Ca, Mg, but not S from loblolly pine feedstocks as compared with water leaching.

XRF Analysis of Water Pretreated/Leached Banagrass to Determine the Effect of Temperature, Time, and Particle Size on the Removal of Inorganic Elements

X-ray fluorescence (XRF) spectroscopy was used to assess the effectiveness of various mild pretreatment methods for improving the fuel quality of banagrass, a tropical grass. Three types of pretreatment were used with increasing levels of severity: (i) S1 involves dewatering (pressing) only, (ii) S2 where the sample is pressed and leached, and (iii) S3 where pressing–leaching–pressing process is used. In addition, the influence of particle size (2 or 60–80 mm), leaching water temperature (25 or 75 °C), and leaching time (1 or 3 min) on the extraction of inorganic elements was examined. The results show that the S3 pretreatment is the most effective and that reducing the particle size has a more significant effect than increasing leaching temperature or time. Using a 2 mm particle size at 75 °C for 3 min produced the greatest effect, removing 50–60 wt % of the Na, ∼65 wt % Mg, ∼90 wt % P, ∼90 wt % K, ∼55 wt % S, and ∼95 wt % Cl. Using dewatering alone (S1) to pretreat the banagrass was the least effective ...

Optimization of bio-oil yields by demineralization of low quality biomass

Lignocellulosic biomass contains inorganic elements (ash) that are known to act catalytically during fast pyrolysis and result in a decrease of the process' selectivity towards the desired liquid product. In this work, the removal of inorganic elements from two forestry residues, two agricultural residues and two energy crops was studied with the aim to maximize the liquid product yield from the fast pyrolysis process. The biomass samples were washed with water and solutions of nitric or acetic acid and the effects of time, temperature, acid type and acid concentration in the washing solution were studied. The original and the pretreated biomass samples were then pyrolyzed in a bench-scale fixed bed reactor in order to investigate the effects of the demineralization on the yields and composition of the pyrolysis products. Washing with water was effective for the removal of up to 42% of the inorganics in the biomass samples, whereas washing with acidic solutions achieved inorganics removal higher than 90%. The most important factor during the biomass pretreatment proved to be the washing temperature; higher temperatures (50 °C) were more effective for the removal of the inorganics than room temperature. The type of acid used in the washing solution was also an important factor, as nitric acid proved to be more effective than acetic acid. In the pyrolysis experiments, the demineralized biomass samples yielded less gas products and solid residue, while the selectivity towards the liquid product was substantially increased in all cases.

Mineral Matter Identification in Nallıhan Lignite by Leaching with Mineral Acids

Coals are heterogeneous, complex noncrystalline macromolecules having both organic and inorganic materials that contain some inorganic constituents. Some techniques have been applied to this fossil fuel in order to remove these undesired inorganic parts from the organic part. Chemical demineralization is one of the suitable methods for removal of inorganic elements although it is an expensive way. But by this method, many elements are leached effectively from the lignite body from the point of economic view because these inorganic parts may cause some undesired deleterious effects. In this study, the demineralization effect of some aqueous acids of 5% such as HCl, H2SO4, HNO3, and HF was studied. The effect of these mineral acids was shown by X-ray spectroscopy.

Characterization of Some Pakistani Coals

Four Pakistani coal samples, in pulverized and screened form, were subjected to density separation, using a series of liquids of various densities, to obtain sink–float fractions. These fractions were extracted with ammonium acetate solution. The virgin, as well as the residual, sink–float fractions were ashed and the ashes were dissolved in an acid mixture. The solutions were analyzed for identification of Cu, Mn, Zn, Fe, Ca and Mg (combined), Na, and K. Some of these elements were found to be associated with float fractions. However, a considerable amount has been found to be concentrated in sink fractions. The results also show that substantial amounts of the elements have been leached with ammonium acetate solution, which indicate their organic affinity. It is inferred, from the results, that density separation can be effectively used for the removal of inorganic elements from these coals. The method also provides a basis to study the organically based elements.

98/02694 The removal of inorganic elements from high-rank coals by agglomeration with vegetable oils: Garcia, A. B. et al. DGMK Tagungsber., 1997, 9702, (Proceedings ICCS '97, Volume 1), 511–514.

98/02694 The removal of inorganic elements from high-rank coals by agglomeration with vegetable oils: Garcia, A. B. et al. DGMK Tagungsber., 1997, 9702, (Proceedings ICCS '97, Volume 1), 511–514.