Anthracite Mixture Research Articles

Investigation of the combustion and fuel properties of slurry fuels formed by biomass and coal

In the study, the combustion and fuel properties of slurry fuels, which are formed by mixing biomass as agricultural waste, sludge swage and algae, and coal as lignite and anthracite in certain proportions, were investigated. The energy properties of new slurry fuels were compared with fossil fuels such as lignite and anthracite, according to the Van Krevelen diagram used. The required stoichiometric air-fuel ratio (SAFR) amount in the burner was calculated during the combustion process. The real fuel-air ratio (RFAR) amount in the burner was determined during the combustion process according to the excess air coefficient (λ) value of 1.5.; as agricultural waste Rice Husks (RH), Corn Cobs (CS), Walnut Shells (WS), Sunflower Shells (SS), Olive Cake (OC), Woodchips (WC) and as other biomass; Brown algae, sewage sludge have been used. As lignite, eight different types with low fuel properties and anthracite, which is the best coal fuel, were used. In the study, the H/C ratio was found to be 1.126 for the mixture of Anthracite + Sewage Sludge + Sunflower Shells (SS) depending on the sewage sludge for the slurry fuels mixture. If it is dependent on Algae, a value of 1.243 was calculated for the mixture of Muğla Ikizköy + Algae + Sunflower Shells (SS). The O/C ratio was found to be 0.242 for Anthracite + Sewage Sludge + Olive Cake (OC) depending on the sewage sludge for the slurry fuels mixture. For Algae, a value of 0.129 was calculated for the mixture of Anthracite + Algae + Olive Cake (OC).

Influence of Molding Technology on Thermal Efficiencies and Pollutant Emissions from Household Solid Fuel Combustion during Cooking Activities in Chinese Rural Areas

Resident combustion of solid fuel has been widely acknowledged as a high potential for pollutant reduction. However, there is a marked asymmetry between more pollutant emission and less burned volatiles of biomass and coal in the combustion process. To study the solid fuel optimum combustion form in a household stove, both the pollution reduction and energy efficient utilization of crop straws and coals were investigated. Taking the molding pressure and clay addition ratio as variable process conditions, the research of bio-coal briquette (made from the mixture of anthracite and biomass) was implemented in the range of 15~35 MP and 5~15%, respectively. Biomass and coal work complementarily for each other’s combustion property development. In particular, the pyrolysis gas produced by biomass low-temperature devolatilization is featured with low ignition point and is distributed in the bio-coal briquette. Its own combustion provides energy for anthracite particle combustion. Consequently, a positive effect was identified when bio-coal briquettes were used as residential fuel, and further improvement manifested in reducing more than 90% of particle matter (PM) and achieving about twice the thermal efficiencies (TEs) compared with the mass-weighted average values of coal briquettes and biomass briquettes. 88.8 ± 11.8%, 136.7 ± 13.7% and 81.4 ± 17.7% more TEs were provided by wheat straw–coal briquettes, rice straw–coal briquettes and maize straw–coal briquettes. 93.3 ± 3.1% (wheat straw–coal), 97.6 ± 0.2% (rice straw–coal) and 90.4 ± 2.2% (maize straw–coal) in terms of PM2.5 emission factors (EFs) was reduced. For bio-coal briquette, a 25 MPa and 10% addition were determined as the optimum molding pressure and clay addition ratio. Bio-coal briquettes with higher TEs and lower PM EFs will bring about substantial benefits for air quality promotion, human health and energy saving.

Catalytic Co-Combustion of Peat and Anthracite in a Fluidized Bed

The catalytic combustion of peat, anthracite, and their mixture in a ratio of 40 : 60 wt % was studied. The addition of peat with a high yield of volatiles to anthracite increased the degree of burnout of the mixture. When the commercial aluminum-copper-chromium oxide catalyst IK-12-70 was used (bed height 1 m, process temperature 700–750°C, particle size of solid fuel less than 1.25 mm), the degree of burnout was 98.2% (peat), 50.9% (anthracite), and 74.2% (peat–anthracite mixture). For large particles of a shaped peat–anthracite mixture with an equivalent diameter of 11.6–18.6 mm, burnout in the upper part of the fluidized bed of the catalyst was 80.5%. The degree of burnout of large particles fed into the lower part of the fluidized bed was evaluated taking into account the degree of burnout of small particles that passed the bed. When large particles of the shaped peat–anthracite mixture were fed, burnout reached at least 95% at a temperature of 700–750°C and a catalyst bed height of 1 m. To avoid accumulation of ash particles in the fluidized bed, the particle size of peat and anthracite in the shaped fuel should not exceed 1–1.5 mm when using a catalyst with a particle size of 2 mm.

Catalytic Fluidized-Bed Co-Combustion of Peat and Anthracite

Results of the studies of catalytic combustion of peat, anthracite, as well as the mixture at the peat to anthracite weight percent ratio 40/60 are discussed. The degree of the mixture burning-off was shown to increase when peat evolving large quantity of volatile substances is added to anthracite. The burn-up degrees of the solid fuel particles less than 1.25 mm in size were 98.2 % of peat, 50.9 % of anthracite, 74.2 % of the peat and anthracite mixture at 700–750 °C and 1 m height bed of the industrial aluminum-copper-chromium oxide catalyst IC-12-70. In combusting coarse particles (equivalent diameter 11.6–18.6 mm) of molded peat and anthracite mixture, the burn-up degree was 80.5 % at the top of the fluidized catalyst bed. The burn-up degree of the coarse particles fed to the bottom of the fluidized bed was estimated with allowance for the burn-up degree of fine particles moving through the bed. With the coarse molded particles of the peat and anthracite mixture fed to 1 m height catalyst bed, the burn-up degree was shown to reach no less than 95 %. When the catalyst used is 2 mm in size, the peat and anthracite particles comprised in the molded fuel must be no more than 1–1.5 mm in size in order to prevent from ash accumulation in the fluidized catalyst bed.

Effect of circulating ash from CFB boilers on NO and N2O emission

NO and N2O emissions from circulating fluidized bed (CFB) boilers are determined by their formation and destruction rates in the furnace. The effect of circulating ash from a CFB boiler on NO and N2O emissions were investigated in a laboratory-scale fluidized bed reactor. The results show that the residue char in circulating ash and the CO generated from the char play an important role in NO reduction and N2O formation; however, active components of circulating ash such as CaO, Fe2O3 accelerate the decomposition of N2O. Experiment was also conducted on a 75 t/h CFB boiler fueled with the mixture of anthracite and biomass. The lower residue carbon content of circulating ash in this experiment is lower; therefore, the reacting rate of NO deoxidize is limited. This result verified the conclusion of laboratory research.

High temperature air-blown gasification of Korean anthracite and plastic waste mixture

Korean anthracite is too high in ash contents and low in calorific value to be used as an industrial energy source, the demand for anthracite has rapidly decreased and its competitiveness weakened. To overcome the problem, a mixture of Korean anthracite and plastic wastes low in ash and high in calorific value was manufactured. A 1.0T/D fixed bed gasification process was developed to understand the gasification characteristics of the mixtures and secure operation technology using Korean and Chinese anthracite. For the Korean anthracite, the syngas composition and heating value are varied from 10 to 20% and from 300 to 800 kcal/Nm3 as a function of steam/air/fuel ratio. Therefore, it is concluded that Korean anthracite is hard to gasify because of low reactivity. For the Chinese anthracite low ash content and higher heating value than domestic anthracite, the syngas composition was maintained at about 20–40% and the calorific value was 800–1,300 kcal/Nm3. A reformer using high-temperature air/steam was installed just after the gasifier to combust and convert tar and soot into syngas. We confirmed that the amount of generated tar and soot showed a salient difference after running the reformer. In the future, gasification experiments of manufactured mixtures of anthracite and plastic waste using 1.0T/D fixed bed gasifier will be performed.

Pressure fluctuation properties in combustion of mixture of anthracite and bituminous coal in a fluidized bed

The combustion characteristics of a mixture of anthracite and bituminous coal were studied in a 0.155 m i.d. fluidized bed combustor (FBC). The properties of the pressure fluctuation for the bed such as the standard deviation, cross-correlation function, dominant frequency and the power spectral density function were obtained through statistical analysis. To interpret the combustion characteristics in the FBC with uniform or multi-sized particles of anthracitebituminous coal mixture, the properties of pressure fluctuation were determined as a function of the particle size distribution and anthracite mixing fraction. In the present work, it is known that the combustion region could be obtained from the analysis of pressure fluctuation properties, and the mixed-firing of anthracite-bituminous coal is related to the reaction models of both coals and particle size distribution. Moreover, the relation between coal size distribution and static mean pressure, and the ignition region could be obtained from the mean pressure profile.

Removal of hydrocarbons from Nile water

The need to remove hydrocarbons from water supply sources raises questions on the efficiency of the present water treatment processes in removing hydrocarbons. Therefore, the effectiveness of physicochemical processes involving chlorination, chemical coagulation and sand filtration were investigated. The effect of variable filtration media was also examined. In addition, the use of an activated carbon column was considered, and the effect of different retention times was evaluated. Results of this study showed that chemical coagulation using alum and Nalco removed only 32% of the total hydrocarbons and 80% of turbidity. Use of sand and a mixture of anthracite and sand filters showed additional removal of hydrocarbons and turbidity during the continuous filtration process. Increasing the anthracite depth relative to the total effective filtration depth increases the efficiency of the filter. Adsorption on granular activated carbon was shown to be an effective means for the removal of hydrocarbons. Results obtained indicated that the carbon adsorption capacity increases linearly as the retention time increases.

Operation of Sunbury Steam-Electric Station Using Pulverized-Anthracite Fuel

Abstract The largest deposits of anthracite in the United States are located in north and central eastern Pennsylvania. Only a few central stations burn this type of fuel, and prior to World War II those stations able economically to justify its use, were relatively small in size. Pennsylvania Power & Light Company, whose service area includes a large segment of the anthracite region, is a pioneer in the burning of anthracite and is the largest single consumer of this fuel in the United States, having burned 2,325,500 net tons in 1951. During 1949 this company completed the installation of four 400,000 lb per hr steam generators at Sunbury Steam Electric Station located between Shamokin Dam and Hummels Wharf on the Susquehanna River near Sunbury, Pa. This paper presents the design features peculiar to the handling, pulverizing, and burning of anthracite, as well as some of the problems encountered during the first 3 years of operation. Reference is also made to a third unit, placed in service in 1951, which burns a mixture of anthracite and bituminous coal and a fourth unit, in the process of construction, which will employ the reheat cycle and also will burn an anthracite-bituminous coal mixture.