中美两国煤炭产量、能耗、矿难比较分析

中、美两国都是煤炭资源非常丰富的国家。从能源消费结构来看,煤炭依然在两国能源消费总量中占重要地位。中国既是一个煤炭生产大国,又是一个煤炭消费大国,中国对煤炭的需求量远远大于美国。但是伴随着中国煤炭行业红火发展的是触目惊心的矿工死难数字,因此,中国矿工死难数字以及死亡率必须引起中央、地方政府以及各个部门的重视。

Effects of Different Biochar Dosages and Types on Growth, Yield and Output Value of Flue-cured Tobacco in Hanzhong Area

[Objective] This study was to investigate the effects of different biochar dosages and trpes on growth, yield and output value of flue-cured tobacco in Hanzhong. [Methods] In May-September of 2013, Xiaonanhai Town, Nanzheng County, Hanzhong City, a field experiment was carded out to study the effects of- biochardosage and type on tobacco agronomic traits, yield and output value in each growth period. [Results] Biochar application significantly increased plant height, stem diameter and leaf size in the early growth pedod, and raised tobacco yield, output value and the proportion of high grade leaf： With the increase of biochar dosage, tobacco agronom~ traits were significantly improved, and yield, output value and proportion of high-grade tobacco leaves also increased significantly, and the highest tobacco yield and output value occurred at the dosage of 900 kg/hm2. Agronomic traits of tobacco leaves with the application of rice husk char and wheat straw char were significantly better than those with the application of peanut shell char, appli- cation of rice husk char was more conducive to the development of leaves in the vigorous pedod and stems in the squaring period, but straw char was beneficial to improvement of plant height and leaf number in the vigorous period and leaf growth in the squaring period, and application of rice husk char had the best effect on the increases of yield and output value of tobacco leaves. [Conclusion] Application of biochar is an effective measure forimproving tobacco-planting soil and promoting the growth and development of tobacco in Hanzhong, biochar application amount should be controlled at about 600-900 kg/hm2, and rice husk char is the preferred choice as soil improvement material.

Flotation of Brazilian and Colombian Coals Using a Negative Bias

Brazil and Colombia have large reserves of coal. Those reserves in Brazil are located predominantly in the south and the main reserves in Colombia are located in the north. Despite the relative ease of exploitation, these resources have been underestimated as a source of energy. Currently, these countries are developing projects and partnerships aiming to qualify this mineral resource, adding quality to the final product of the processing plants. In this scenario, the processing of Brazilian and Colombian coal in flotation columns appears as a promising alternative, having been successful in mineral systems containing fine particles. The paper aims to study the overall process of column flotation for a specific Brazilian coal and a specific Colombian coal. The material used in this study consists of fine coal from Brazil （Copelmi） and Colombia （Cerrejon）. The objective is to recover carbonaceous matter and reduce the ash and contaminants grade. The two coals were floated using a negative bias in a 5 cm diameter conventional flotation column of 5 m high. Flotation parameter investigated included air velocity in the range 0.6 to 1.5 cm/s. For all runs, a constant negative bias of-0.25 cm/s and a pulp concentration of 8% w/w were used. For Cerrej6n coal, 300 g/ton of frother and 907 g/ton of collector was used, whereas for Copelmi coal, 600 g/ton of frother and 1,815 g/ton of collector was employed. The frother was a commercial Aerofroth 65 （AF65）, whereas the collector was Kerosene. For the Colombian coal, in general, yield, organic recovery, ash recovery and water recovery decreased with the increasing air rate. However, for Brazilian coal the air rate had no significant effect. For Colombian coal, the highest yield （60% w/w） and organic recovery （69% w/w） were obtained at the lowest air rate （0.6 cm/s）.

A dynamic optimization model of an integrated coal supply chain system and its application

Various nodes,logistics,capital flows,and information flows are required to make systematic decisions concerning the operation of an integrated coal supply system. We describe a quantitative analysis of such a system. A dynamic optimization model of the supply chain is developed. It has achieved optimal system profit under conditions guaranteeing a certain level of customer satisfaction. Applying this model to coal production of the Xuzhou coal mines allows recommendations for a more systematic use of washing and processing,transportation and sale resources for commercial coal production to be made. The results show that this model,which is scientific and effective,has an important value for making reasonable decisions related to complex coal enterprises.

Heat Transfer Validation and Comparative Evaluation of Biochar Yield from Pyrolysis Cook Stove

The developing world still largely depends on biomass, such as wood, animal dung and agricultural waste for domestic fuel sources that are typically burned in traditional stoves. Ethiopia has different biomass resource for biochar production, through pyrolysis cook stove co-producing biochar. Coffee husks are the major solid residues from the handling and processing of coffee in the study area. This study was to evaluate the biochar co-producing pyrolysis cook stove with respect to heat transfer through the bed and biochar yield. From allothermal type of pyrolysis cook stove, the stove design was selected for both the computational fluid dynamic （CFD） simulation and experimental measurements. ANSYS 14.5 was used for CFD simulation of the wood combustion. The production of biochar from coffee husk, corncob and sawdust at different heating times, bed and stove surface temperature were undertaken. Bulk density, pH and surface area of the biochar were measured. While good agreement between simulation and experimental result was obtained in the conduction phase during pyrolysis, deviation between the two on account of the effect of volatile gas in changing the temperature trend within the biomass bed was noticed. Within the biomass type, the maximum mean biochar yield （38.91%） was seen from coffee husk. In the case of different stove designs, the minimum mean biochar yield （27.11%） was found from normal Anila stove. The pH of biochar is found to be significantly affected by the type of biomass （9.83 mean for corncob and coffee husk, 6.43 mean for sawdust）, heating time （9.19 mean for 90 min and 8.01 mean for 30 min） and stove type （9.52 mean for normal Anila and 8.01 mean for flangeless Anila continuous feeding type）. In fact, the type of biomass is observed to significantly affect the bulk density and surface area ofbiochar.

Conocarpus Biochar Induces Changes in Soil Nutrient Availability and Tomato Growth Under Saline Irrigation

Thermally modified organic materials commonly known as biochar have gained popularity of being used as a soil amendment.Little information, however, is available on the role of biochar in alleviating the negative impacts of saline water on soil productivity and plant growth. This study, therefore, was conducted to investigate the effects of Conocarpus biochar(BC) and organic farm residues(FR) at different application rates of 0.0%(control), 4.0% and 8.0%(weight/weight) on yield and quality of tomatoes grown on a sandy soil under drip irrigation with saline or non-saline water. The availability of P, K, Fe, Mn, Zn and Cu to plants was also investigated. The results demonstrated clearly that addition of BC or FR increased the vegetative growth, yield and quality parameters in all irrigation treatments. It was found that salt stress adversely affected soil productivity, as indicated by the lower vegetative growth and yield components of tomato plants. However, this suppressing effect on the vegetative growth and yield tended to decline with application of FR or BC, especially at the high application rate and in the presence of biochar. Under saline irrigation system, for instance, the total tomato yield increased over the control by 14.0%–43.3% with BC and by 3.9%–35.6% with FR. These could be attributed to enhancement effects of FR or BC on soil properties, as indicated by increases in soil organic matter content and nutrient availability. Therefore, biochar may be effectively used as a soil amendment for enhancing the productivity of salt-affected sandy soils under arid conditions.

Comparative Assessment of the Effect of Wastewater Sludge Biochar on Growth,Yield and Metal Bioaccumulation of Cherry Tomato

To investigate the potential effects of wastewater sludge and sludge biochar on growth, yield and metal bioaccumulation of cherry tomato （Lycopersicon esculentum L.）, a pot experiment was carried out under greenhouse environment with three different treatments, control soil （CP）, soil with wastewater sludge （SS） and soil with sludge biochar （SB）, to reveal the comparative effect between the amendments of wastewater sludge and sludge biochar. The soil used for pot experiment was Chromosol. Wastewater sludge and sludge biochax produced through pyrolysis process at 550 ℃ were applied at 10 t ha-1. No significant difference was found in growth and production of cherry tomatoes between wastewater sludge and sludge biochar applications to the soil. The accumulation rates of metals in the fruits were lower in the treatment with sludge biochar than in the treatment with wastewater sludge. The study highlights the benefits of risk mitigation from toxic metal accumulation in fruits using wastewater sludge and sludge biochar as soil conditioners.

Synergistic Effects of Biochar and NPK Fertilizer on Soybean Yield in an Alkaline Soil

Biochar effects on legume growth and biological nitrogen fixation have been studied extensively, mostly in acidic soils with laboratory produced biochar. In the present study, a pot experiment in a full factorial experimental design was performed to examine soybean yield and nodulation of three genotypes grown with or without biochar and NPK fertilizers in an alkaline soil. We observed synergistic effects of biochar and NPK fertilizer applications on biomass and seed yields for all three soybean genotypes. Total biomass production and seed yield increased on average by 67% and 54%, respectively, with biochar and by 201% and 182% with NPK fertilizer application compared to the control. When applications of biochar and NPK fertilizer were combined, the increases were 391% and367%, respectively. However, the biomass production in the control was very low(692 kg ha-1) due to a high soil p H(8.80). The nodulation increased with biochar and NPK fertilizer applications, and was largest with the combined application. A correlation was found between leaf chlorophyll content(single photon avalanche diode value) and nodule number. We suggested that the synergistic increase in yield was due to a decrease in soil p H caused by biochar and NPK fertilizer applications thereby increasing P availability in this alkaline soil.

Biomass and Energy of Casuarina equisetiofolia Plantations in Southeast Coast of China

The biomass and energy production of Casuarina equisetifolia plantations aged 14 were studied in Huian County, Fujian Province, Southeast of China. The standing crop biomass was 152.60 t/ha, in which the biomass of bole was 67.02 t/ha, accounting for 43.94 % of the total, while that of root was 36.83 t/ha and 24.14 %, respectively. Net primary productivity was 10.17t/(ha.a).The range of gross caloric of components was 19.29～20.23 kJ/g, with the average 19.70 kJ/g. The standing crop energy was 2 987×10^6 kJ/ha. Net energy production was 196.8×10^6 kJ/ha, while solar energy conversion efficiency was 0.90%.