Based on isothermal thermogravimetric analysis (TGA) and kinetic equations, the optimization toolbox of MATLAB was applied to study the effects of particle size and heating rate on the pyrolysis characteristics and kinetics and to obtain the mechanism function and kinetic parameters of Yuanbaoshan coal at four different particle sizes and heating rates. The pyrolysis characteristics of he samples were analyzed using thermogravimetric (TG) curves and differential thermogravimetric (DTG) curves. The results show that the coal pyrolysis process is strongly affected by heating rate and particle size. As the heating rate increases, the temperature of volatile matter initiation increases, the total volatile matter evolved decreases and the DTG peak shifts toward higher emperature. As the particle size decreases, the temperature of volatile matter initiation of the coal sample decreases and the maximum rate of mass loss increases. In the pyrolysis of coal, the activation energies of the samples were found to increase with growing particle size and decreasing heating rate for both of the devolatilization temperature stages. In the lower temperature stage, the coal samples show a great difference in mechanism function at different particle sizes and heating rates.

On the basis of the physical and chemical performance of Huadian oil shale and the design experience of Huadian 65 t/h oil shale-fired circulating fluidized bed (CFB) boiler operation, this paper introduces several main characteristics of oil shale, such as platy structure, high volatile and Ca/S content, and low ignition temperature, which are relevant to the design of CFB boiler, and analyses key design technologies of largescale oil shale-fired circulating fluidized bed boiler. The design principles of large-scale oil shale-fired CFB boiler are suggested: (1) to adopt a IIshape configuration natural circulation mode with medium-temperature cyclone with downward gas exhaust, reliable antiwear technology and self-desulfurization technology; (2) to determine a circulating ratio of 6, hot state superficial air velocity of 5–6 m/s, combustion portion of about 0.5–0.6 in dense phase zone, and air velocity at the nozzle hole of air cap of 50–60 m/s; (3) to adopt an igniting system with hot gas generator below distributor plate and oil guns as auxiliary ignition device above distributor plate, and fluidized bed ash cooler retrieving the heat taken by hot slag. Lastly, the design scheme of 420 t/h superhigh pressure oil shale-fired CFB boiler is put forward and the general configuration and technical data are given at the end of this paper.

The comprehensive utilization of oil shale is a new promising technology achieving high utilization-factors for both oil shale’s chemical and energy potentials, and avoiding serious environmental impacts. For this technology, it is an urgent issue how to obtain shale oil with a high yield and as well as treat shale char efficiently and economically. In this present work, retorting experiments of three type I oil shales were performed using an aluminum retort, and the effect of retorting temperature, residence time, particle size and heating rate on the yield of shale oil was studied at low retorting temperatures ranging from 400℃to 520℃, respectively, at which shale char obtained has good combustion properties. The experimental data show that an increase in the retorting temperature, the residence time and the heating time has positive significant effect on improving the yield of shale oil, and a middle particle size is helpful for increasing the oil yield as well. The grey system method was applied to evaluate the effect of retorting factors on the yield of shale oil, showing that the retorting temperature is the most marked factor influencing the yield of shale oil.

In this paper, an industrial cold experiment was conducted for studying regulating characteristics of a loop seal in a 65 t/h oil shale-fired circulating fluidized bed (CFB) boiler. The starting characteristic of the loop seal, and the effect of the supplying air and the fluidizing air in the loop seal were investigated. Compared with other regulating modes, the combined regulating mode of keeping the fluidizing air rate constant and regulating the supplying air rate can make the loop seal obtain better regulating quality, and offer more reliable guarantee for steady operation of the CFB boiler as well. In order to prevent circulating material depositing and slagging at the bottom of the loop seal, it was suggested that the fluidizing air rate and the supplying air rate is 2-3 and 1.2-1.5 times of the minimum fluidizing velocity of circulating material, respectively. These experimental results may be used as a reference for regulating the loop seal of the 65 t/h CFB boiler in hot condition and designing a new loop seal.

In this paper, a model on attrition of quartzite particles as an inert bed material in fluidized beds has been established on the particle-particle collision. For the convenience of describing the attrition of quartzite particles in fluidized beds, we chose the attrition rate constant (kARC) as one main characteristic parameter to develop the model. In order to verify the validity of the developed model, an attrition experiment of quartzite articles has been carried out in a lab-scale circulating fluidized bed. The predicted results from the population model were close to the experimental data as far as the engineering use is concerned. Finally, a sensitivity analysis was performed by using the developed model to examine effects of initial particle diameter, attrition time, and fluidization number on kARC.

Curie-point pyrolyser is an instrument that can be used to analyze powder or slurry samples at medium heating rates. It can keep a constant heating rate to heat up the samples until the wire temperature reaches Curie-point temperature and remains the same temperature. In this paper, coal–water slurry (CWS) and its parent coal were studied by using a Curie-point pyrolyser. Kinetic parameters of pyrolysis were calculated and apparent activation energy of CWS obtained is 16.362 kJ/mol, which is a little higher than that of its parent coal, 12.691 kJ/mol. The experimental curves show lean S shape and the heating rate are obtained, which are 617 K/s and 834 K/s, respectively.

The effects of oxygen concentration, particle size, and heating rate on the coal combustion characteristics under an O2/CO2 atmosphere were investigated. The results indicated that the oxygen concentration played the most important role. As the oxygen concentration increases, the ignition and burnout temperatures decrease and the comprehensive combustion property index S increases. Moreover, the improvement of the oxygen concentration intensified the effects of the other factors. The ignition mechanism changes from heterohomogeneous type to homogeneous type as the oxygen concentration increases. The ignition and burnout temperatures decrease slightly as the mean particle size decreases, and the index S increases measurably as the mean particle size decreases. The heating rate has different effects on the ignition temperature, burnout temperature, and index S at different oxygen concentrations.

Combustion of super fine particles is a new pulverized coal combustion technique. Compared with conventional combustion techniques, it has the advantages of good flame stability, high burnout, low NOx release, and low comprehensive cost. Using NETZSCH thermobalance, STA 409C, and maintaining the test conditions for all the samples at the heating rate of 20 °C/min, the paper investigated the combustion properties of Heshan (Hs) subbituminous coal and Jincheng (Jc) lean coal, each in four different average sizes. Significant improvement of combustion properties was observed when particle size was reduced down to 0-20µm.

Pyrolysis of tank bottom oil sludge was investigated to summarize the pyrolysis characteristics through analyzing the change of mass loss, pyrolysis gas compositions in heating process. For this propose, various approaches including thermogravimetric analysis (TGA), CNHS/O elemental analysis, electrically heated fixed bed quartz reactor coupled with Vario Plus emission monitoring system, and oil-gas evaluation workstation (OGE-II) equipped with a flame ionization detector (FID) were used. The pyrolysis reaction is significant in the range of 473-773K where multi-peak DTG curves can be gained. Higher heating rate increases the carbon (C) and sulfur (S) contents but decreases hydrogen (H) content in solid residues. The major gaseous products excluding N2 are CHs (Hydrocarbons), CO2, H2, CO. The yield of CHs is significant in the range of 600-723 K. Higher heating rate causes the peak intensity of CHs evolution to increase and the CHs evolution to move towards a high-temperature region. Around 80% of total organic carbon content (TOC) in oil sludge can be converted into CHs in pyrolysis process. The CHs data were used for kinetic analysis by Vyazovkin model-free iso-conversion approach. Dependences of the activation energy on the degree of conversion obtained from different methods were compared.

Incineration has been proven to be an alternative for disposal of sludge with its unique characteristics to minimize the volume and recover energy. In this paper, a new fluidized bed (FB) incineration system for treating oil sludge is presented. Co-firing of oil sludge with coal–water slurry (CWS) was investigated in the new incineration system to study combustion characteristics, gaseous pollutant emissions and ash management. The study results show the co-firing of oil sludge with CWS in FB has good operating characteristic. CWS as an auxiliary fuel can flexibly control the dense bed temperatures by adjusting its feeding rate. All emissions met the local environmental requirements. The CO emission was less than 1ppmor essentially zero; the emissions of SO2 andNOx were 120–220 and 120–160mg/Nm3, respectively. The heavy metal analyses of the bottom ash and the fly ash by ICP/AES show that the combustion ashes could be recycled as soil for farming.