Preparation of CaO-containing carbon pellets from coking coal and calcium oxide:Effects of temperature,pore distribution and carbon structure on compressive strength in pyrolysis furnace

CaO-containing carbon pellets(CCCP)were successfully prepared from well-mixed coking coal(CC)and calcium oxide(CaO)and roasted at different pyrolysis temperatures.The effects of temperature,pore distribution,and carbon structure on the compressive strength of CCCP was investigated in a pyrolysis furnace(350-750℃).The results showed that as the roasting temperature increased,the compressive strength also increased and furthermore,structural defects and imperfections in the carbon crystallites were gradually eliminated to form more organized char structures,thus forming high-ordered CC.Notably,the CCCP preheated at 750℃exhibited the highest compressive strength.A positive relationship between the compressive strength and pore-size homogeneity was established.A linear relationship between the com-pressive strength of the CCCP and the average stack height of CC was observed.Additionally,a four-stage caking mechanism was developed.

Preparation and performance analysis of a coking coal dust suppressant spray

Coking coal dust is extremely hydrophobic;therefore,combination with droplets in the air is difficult and dust suppression is challenging.Here,a dust suppressant spray for coking coal dust was studied in order to improve of the combination of droplets and coking coal dust.Based on monomer optimization and compounding analysis,two surfactant monomers,fatty alcohol ether sodium sulfate(AES)and sodium dodecyl benzene sulfonate(SDBS)were selected as the surfactant components of the dust suppressant.The surfactant monomers were combined with four inorganic salts and the reverse osmosis moisture absorption of each solution was determined.By combining the reverse osmosis moisture absorption values with the water retention experimental results,CaCl_(2)was identified as the optimal inorganic salt additive for the dust suppressant.Finally,the optimal concentration of each component was obtained using orthogonal experimental design i.e.,AES(0.03%),SDBS(0.05%),and CaCl_(2)(0.4%).The dust suppressant solution formulated using this method had a high moisture absorption capacity and excellent performance.

Batch methanogenic fermentation experiments of wastewater from a brown coal low-temperature coke plant

Coke plant effluents with high contents of organic compounds are mainly treated by biological aerobic fermentation after physical pre-treatment. In this study, a brown coal condensate wastewater from a low temperature coking process was fermented under methanogenic conditions in discontinuous experiments. By this fermentation, acetate, propionate, and the main polyphenolic compounds （catechol, resorcinol and hydroquinone） were degraded to a level below the detection limit. The COD was reduced by 72% with a residual concentration of 2.1 g/L. This anaerobic fermented wastewater had a residual BOD5 of 0.66 g/L and 2.2 L CH4 were formed per litre of wastewater. An abiotic pre-treatment for this wastewater with air had a negative effect on the COD reduction and decrease of colour on the methanogenic fermentation due to the autoxidation of polyphenolic compounds to humic-like compounds. This study showed that methanogenic fermentations in the treatment sequence of brown coal coking wastewaters could reduce energy consumption for aeration in further treatment processes and had the potential for a better effluent quality due to a less formation of recalcitrant humic-like compounds.

Optimum active and inert ratios for different metamorphic grade coals

In order to quantitatively describe the difference of optimum active and inert ratio of various metamorphic grade coking coals, the rule of coke micro-strength index （MSI）, determinated by adding different proportions of inert content to ten kinds of single coal, changing with active and inert ratio has been investigated. Three kinds of change rule of the MSI of ten kinds of single coal changing with active and inert ratio have been obtained in the research. It has been demonstrated that Gauss curve model is the optimal model to describe the optimum active and inert ratio of different metamorphic grade coals. On this basis, the optimum active and inert ratio of different metamorphic grade coals can be given.

Effect of Indian Medium Coking Coal on Coke Quality in Non-recovery Stamp Charged Coke Oven

The maximum possibility of utilizing the Indian coking coals and inferior grade coking coal for producing metallurgical coke through non-recovery stamp charging tech_nology was investigated. Indian indigenous coals contained low percent of vitrinite （〈50%） and higher content of ash （〉15%） compared to imported coking coal. Therefore, the selection of appropriate proportion of different types of coals was a major challenge for coke makers. Coal blend selection criterion based on a single coefficient, named as composite coking potential （CCP）, was developed. The use of increased proportion of semi-soft coal （crucible swelling number of 2.5） and high ash （≥15%） indigenous coal in the range of 20%- 35% and 20%-65% respectively in the blends resulted in good quality of coke. Plant data of a non recovery coke oven were used for developing and validating the model. The results showed that the coke strength after reaction （CSR） varied in the range of 63.7%-67.7% and the M40 value was between 81.8 and 89.3 in both the cases.

Co-Ce-Ni Ternary Metal Oxide Modified N-activated Carbon:The Superior Low Temperature NH3-SCR Performance

Introducing reduced metal and nitrogen species is a powerful strategy to improve the reactivity of carbon-based materials for selective catalytic reduction of NO_(x) with NH_(3).To further improve the NH_(3)-SCR performance of non-pitch coal activated coke(NPAC),a series of metal oxides(e.g.,Co,Ce,and Ni)were loaded on nitrogen modified NPAC.The outstanding performance of NPAC-N-CoCeNi as well as the superior SO_(2)-and H_(2)O-tolerate performance are attributed to the extra electrons caused by the modification of N species,and these extra electrons are more conducive to the electron transfer.More importantly,the interaction of the major active component Co^(3+)and the promoter catalysts CeO_(2),NiOx,or CoNiO_(2) can also increase the charge transfer and produce more oxygen vacancy and unsaturated chemical bonds,leading to improving the redox performance of NPAC-N-CoCeNi.In addition,the NH3-SCR reaction is promoted after the metal oxides co-doping mainly via the Mars-van-Krevelen mechanism.

Ignition Dynamic Parameters for Coke in Cement Calciners

The mathematical ignition model was established and researches ofignition dynamic parameters for coke in some typical coal samplesfrom cement plants was carried out according to circumstances of coalcom- busted in cement plants. In order to get the ignitionintemperature T_pi of carbon particles more accurately, the tem-perature rising experimental method was used and the actual heatingcircumstances for pulverized coal in calciners (in cement plants)werealso considered.

A review on co-pyrolysis of coal and oil shale to produce coke

It has become the top priority for coking industry to rationally use and enlarge coking coal resources because of the shortage of the resources.This review focuses on the potential utilization of oil shale(OS)as a feedstock for coal-blending coking,in which the initial and basic step is pyrolysis.However,OS has a high ash content.If such OS is directly used for coal-blending coking,the coke product will not meet market demand.Therefore,this review firstly summarizes separation and beneficiation techniques for organic matter in OS,and provides an overview on coal and OS pyrolysis through several viewpoints(e.g.,pyrolysis process,phenomena,and products).Then the exploratory studies on co-pyrolysis of coal with OS,including co-pyrolysis phenom-ena and process mechanism,are discussed.Finally,co-pyrolysis of different ranks of coals with OS in terms of coal-blending coking,where further research deserves to be performed,is suggested.

Sensitivity analysis of a methanol and power polygeneration system fueled with coke oven gas and coal gas

The sensitivity analysis of a polygeneration energy system fueled with duo fuel of coke oven gas and coal gas is performed in the study,and the focus is put on the relations among syngas composition,conversation rate and performance.The impacts of the system configuration together with the fuel composition on the performance are investigated and discussed from the point of cascading utilization of fuel chemical energy.First,the main parameters affecting the performance are derived along with the analysis of the system configuration and the syngas composition.After the performance is being simulated by means of the Aspen Plus process simulator of version 11.1,the variation of the performance due to the composition of syngas and the conversion rate of chemical subsystem is obtained and discussed.It is obtained from the result that the proper conversion rate of the chemical subsystem according to the specific syngas composition results in better performance.And the syngas composition affects the optimal conversion rate of the chemical subsystem,the optimal point of which is around the stoichiometric composition for methanol production(CO/H_(2)=0.5).In all,the polygeneration system fueled with coke oven gas and coal gas,which can realize the reasonable conversion of syngas to power and chemical product according to the syngas composition,is a promising method for coal energy conversion and utilization.

High temperature dephosphorus behavior of Baotou mixed rare earth concentrate with carbon

Based on the carbothermal reduction technology applied in industry,the dephosphorization behavior of Baotou mixed rare earth concentrate(Baotite) with carbon at high temperature was investigated.The experimental results showed that both the charred coal and the coking coal were effective carbonaceous reductants for the dephosphorization of the Baotite.Among them,the charred coal was more suitable for the dephosphorus due to its high carbon content and lower volatile and ash.When the rare earth pellets,made by pressing the mixture of the Baotite,charred coal and water in mould,were roasted at 1500 oC for 2 h,its dephosphorus rate was as high as 98%.Roasting temperature was a main factor for the dephosphorus rate,and roast time was the second one.The size of both charred coal and coking coal also had influence on the dephosphorus,and was better less than 150 μm.