Effect Of Inherent Minerals Research Articles

Effects of inherent minerals in bean dregs on biomass reduction roasting: A strategy to maximize benefits and minimize drawbacks

Effects of inherent minerals in bean dregs on biomass reduction roasting: A strategy to maximize benefits and minimize drawbacks

Effects of Inherent Minerals on Pyrolysis Behavior and Kinetics of Jimsar Oil Shale

Effects of Inherent Minerals on Pyrolysis Behavior and Kinetics of Jimsar Oil Shale

Effects of inherent minerals on oily sludge pyrolysis: Kinetics, products, and secondary pollutants

Considerable inherent minerals in oily sludge (OS) caused intricate effects on OS pyrolysis behaviors. This work investigated the effects of individual mineral on pyrolytic products and secondary pollutants by pyrolysis of artificial OS, which was prepared by assembling pure mineral chemicals (SiO2, CaO, MgO, Fe2O3, and Al2O3) with petroleum oil. Results showed that the effects of inherent minerals on OS pyrolysis tightly depended on pyrolysis temperature, where the thermal cracking and secondary reactions of heavy hydrocarbons were promoted at high temperature. Their effects also varied with inherent mineral species. The existence of SiO2 in OS had negligible influences on OS pyrolysis. CaO and MgO were favored for almost invariant quality of liquid product and the lowest total petroleum hydrocarbons (TPHs) content in solid residues. Because CaO and MgO weakened the stabilities of hydrogen bonds and hydroxyls groups and thus accelerating devolatilization of TPHs from OS. Fe2O3 and Al2O3 helped in the lower TPHs content in solid residues as well. Moreover, they were favored for more pyrolytic gases and long chain liquid product though the yield of liquid product decreased. It may attribute to the enhanced deoxidation and polymerization of Fe2O3 and Al2O3. Along with OS pyrolysis, inherent minerals tended to inhibit N/S/Cl-containing pollutants at the stage of dehydration and devolatilization (<358 °C), but promote their releasing at the stage of thermal cracking and secondary reactions (>358 °C). This work might provide inspiration for getting insight into the OS pyrolysis behaviors and proposing clean fuel production strategies.

Insight into the Effect of Inherent Minerals on the Constant Current Electrolysis of Alkaline Coal-Water Slurry

Insight into the Effect of Inherent Minerals on the Constant Current Electrolysis of Alkaline Coal-Water Slurry

Synergistic Catalytic Effect of Inherent Minerals and Specific Structures on the Steam Gasification of Lignite and Anthracite

ABSTRACT The synergistic effects of inherent minerals and specific organic structures in coal on steam gasification were comprehensively investigated herein. The steam gasification of lignite, anthracite, and their corresponding demineralized samples were tested by a laboratory fixed-bed micro reactor system. Lignite showed much higher gasification reactivity than anthracite, which led to a significant reduction of gasification temperature. Moreover, it was proved that minerals could promote the release rate of H2 but decrease the release rate of CO, which resulted in high H2/CO of the syngas for lignite, but the effects of minerals on the steam gasification of anthracite were not so obvious. These gasification behaviors could be attributed to the existence of inherent minerals in lignite, which indicated that inherent minerals had a remarkable catalytic effect on steam gasification, but limited impact on that of anthracite. The inherent minerals and organic structures of coal were characterized by scanning electron microscope-energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy (Raman). The results showed that interactions of inherent minerals with oxygen-containing functional groups such as carboxyl functional groups and the more amorphous carbon structures in lignite played a key role in the catalytic effect during steam gasification.

Characteristics and mechanisms of chlorpyrifos and chlorpyrifos-methyl adsorption onto biochars: Influence of deashing and low molecular weight organic acid (LMWOA) aging and co-existence

The effects of inherent minerals in biochars and low molecular weight organic acids (LMWOAs) on chlorpyrifos and chlorpyrifos-methyl adsorption by biochars are unclear. We examined the sorption of chlorpyrifos and chlorpyrifos-methyl onto giant reed-derived biochars before and after deashing or LMWOA aging. The effect of citric acid (CA) as a co-solute on the sorption of chlorpyrifos and chlorpyrifos-methyl was also investigated. With increasing temperature (300–600 °C), the adsorption capacity of biochars increased from 4.32 to 14.8 mg/g for chlorpyrifos and from 15.0 to 50.5 mg/g for chlorpyrifos-methyl. This can be explained by the fact that higher temperature biochar had more aromatic units and pores for capturing more sorbates. The deashing and LMWOA aging treatments exposed more carbon surfaces and improved the porosity of biochar, thus favoring sorption. Further, the deashing treatment resulted in greater sorption enhancement, when compared with the LMWOA aging treatment. At pH 6.5, CA2− and CA3− chelated Ca2+ via bridging at CA concentration below 10 mmol/L, thus reducing the competition of Ca2+ for aromatic surfaces and COO−/OH groups. When the CA concentration was above 20 mmol/L, CA2−, CA3−, and [Ca(CA)2]x− inhibited the sorption of chlorpyrifos and chlorpyrifos-methyl by competing for carbon sites and pores of biochar. These findings will help guide the practical application of biochar in pesticide-contaminated water and soil, and to better understand the role of biochar in the transport, fate, and bioavailability of organophosphorus pesticides in the rhizosphere.

Effect of inherent minerals on sewage sludge pyrolysis: Product characteristics, kinetics and thermodynamics

Inherent minerals in sludge influence sludge pyrolysis behaviors and the final products. In this study, the effects of inherent minerals on sewage sludge pyrolysis were systematically investigated by studying the pyrolysis behaviors of raw sewage sludge (RS) and HCl-washed sludge (WS), and in combination with thermodynamic equilibrium simulations for the hypothetical mineral-free sludge (AS) assumed. The pyrolysis of RS and WS was performed with a novel online thermogravimetric analyzer equipped with an infrared spectrometer and a gas chromatograph coupled with a mass spectrometer (TG-IR-GC/MS). It was found that inherent minerals influenced both the release of volatile products as a function of pyrolysis temperature, and the development of the physicochemical properties of the derived char. In the temperature range of 300–500 °C, hydrocarbons with more than 4 carbon atoms as well as aromatic compounds showed an increased release during WS pyrolysis, with respect to RS, while hydrocarbons with less than 3 carbon atoms such as CH4 and C3H6 exhibited a decreased release. In addition, the inherent minerals enhanced the release of HCN and NH3, both leading to increased NO2 release, and the release of H2S and COS was also promoted while the release of CH3SH, SO2 and CS2 was mitigated. Kinetic analysis confirmed that a catalytic effect induced by the inherent minerals decreased the activation energy at 300–500 °C. Thermodynamic simulations suggested that inherent minerals influenced sludge pyrolysis and the derived products formation by increasing the total Gibbs energy of the sludge pyrolysis system. Therefore, considerations of sludge inherent minerals should be taken into account during pyrolysis for the purpose of value-added commodity production and pollutant mitigation.

An experimental study of CaSO4 decomposition during coal pyrolysis

Coal with different proportions of CaSO4 was pyrolyzed in a fixed-bed reactor in a temperature range of 500–800°C to study the mechanism of CaSO4 decomposition during coal pyrolysis. The results showed that the presence of coal could greatly promote CaSO4 decomposition at high temperatures, and 87% CaSO4 was decomposed at 800°C during Xiaolongtan lignite pyrolysis, which was mainly attributed to the solid–solid reaction (2C+CaSO4→CaS+2CO2). The effects of inherent minerals, coal type, holding time and coal particle size on CaSO4 decomposition were also discussed. By comparing the CaSO4 decomposition rate between raw coal and demineralized coal, it could be concluded that the inherent minerals could greatly enhance CaSO4 decomposition at high temperatures, which was also be proved by the results of thermogravimetric analysis (TGA). CaSO4 decomposition rate presented a significant decrease with the increase of coal particle size. Four coals used in this study could all promote CaSO4 decomposition, but the promotion effect differed among those four coals which may be attributed to the difference in inherent minerals and the reactivity of coal.

A study of char gasification in H2O and CO2 mixtures: Role of inherent minerals in the coal

The effect of inherent minerals in coal on gasification in H2O and CO2 mixtures was investigated, and the synergistic effect was explained. First, low-temperature ash that has the same state as the inherent minerals in raw coal was prepared by low-temperature ashing with an oxygen plasma at 150°C. The minerals were identified by X-ray diffraction. Then, the coal was successively demineralized with deionized water, HCl, HF, and HCl/HF. Char gasification reactivities of the successively demineralized coals with different mixtures of H2O and CO2 were investigated using a thermogravimetric analyzer at 800°C. The gasification reactivity closely correlated with the Ca content in successively demineralized coals. The calcite present in coal catalyzes the gasification reaction, causing the synergistic effect.

Effect of Inherent Minerals on the Release of Fuel-Nitrogen during Coal Pyrolysis

The formation of NO x precursors (mainly HCN and NH 3 ) from the pyrolysis of Pingshuo coal with or without minerals was studied in a quartz fixed bed reactor. The coal sample in the reactor was heated in two kinds of fashion: at a slow heating rate by temperature-programmed and at a fast heating rate than constant temperature. The experimental results revealed that demineralization by acid washing drastically decreases nitrogen conversion to NH 3 at a fast heating rate and at a slow heating rate, but for HCN, its formation is different at fast heating and slow heating rates. The yield of HCN from demineralized coal is slightly lower than that from raw coal at a fast heating rate and it is the reverse at a slow heating rate. On the other hand, the pyrolysis experiments data of demineralized coal and raw coal added with ash from Pingshuo coal combustion also indicated that minerals in coal play an important role in gaseous-N formation, but the reaction mechanism is different for raw coal and demineralized coal.

Assessment of Chlorine−Alkali−Mineral Interactions during Co-Combustion of Coal and Straw

During co-combustion of coal and straw, ash deposition and pollutants (HCl, aerosols, etc.) formation is significantly influenced by the behavior of chlorine and alkali metals. On the bases of measurement data, the effect of inherent minerals in blended fuels on the release and retention of chlorine and alkali metals is investigated through the equilibrium analysis tool FACT-Win. Si, Al, Ca, Mg, and S may greatly affect the behavior of Cl, K, and Na, where the other minor elements, such as Fe, Ti, and Mn have not much influence. According to measurement data, very low amounts of chlorine and sulfur are retained in bottom, air preheater, and cyclone ash in a pulverized fuel combustor. But in filter ash, the chlorine and sulfur contents are relatively high and the ratio (K + Na)/(Cl + 2S) is close to 1. According to equilibrium calculations, in hard coal co-combustion with less than 50% straw, most of the potassium is combined with aluminosilicates to form KAlSi2O6(s,s2), etc., which can prevent ash deposit...