低阶煤无热载体快速热解炉工艺试验研究

为实现煤炭热解分质梯级利用,提出了低阶煤无热载体粉煤快速热解炉工艺,以印尼褐煤为研究对象,对无热载体粉煤快速热解工艺所产焦油、热解气、半焦等进行分析,验证低阶煤无热载体热解炉工艺的技术可行性。结果表明,试验煤种经低阶煤无热载体粉煤快速热解炉工艺处理后热解焦油产率达11.84%、热解气产率14.08%,半焦产率64.97%,其中焦油产率比格金干馏试验提高了1.49%,半焦发热量较原煤提高了2.63 MJ/kg,热解气有效气体含量达80%以上。表明该低阶煤无热载体粉煤快速热解炉工艺具有热解温度可区域精确控制、热解速度快、焦油产率高、产品品质好等优点。     

高硫煤基活性炭的批量制备

在以高硫低阶煤为原料,采用硝酸钾预氧化后加KOH化学活化的工艺制备活性炭的小试研究基础上,进行了高硫煤基活性炭的批量反应器设计和批量制备实验.原料煤样批处理量1.5kg~2.5kg,在碱炭比为2.0∶1,活化温度850℃,活化时间2.0h的条件下,经酸洗后制备的活性炭苯酚吸附量达233.34mg/g,碘吸附量达1405.00mg/g.     

Relationship between the maximum and the random reflectance of vitrinite for coal from the Upper Silesian Coal Basin (Poland)

The relationship between the maximum and random reflectance of vitrinite, R_max and R_r, for Upper Silesian coal is represented by the equation: R_max=1.090R_r−0.052. When the random reflectance is higher than 0.90%, the difference between R_max and R_r values becomes significant. R_max is a more precise rank indicator, the standard deviation is much smaller than the standard deviation of the random reflectance value, which is larger due to the optical anisotropy of vitrinite.     

Study on the correlation of lab assay and field test for fouling-release coatings

In this paper, two organisms, diatom and Ulva spore, were employed to evaluate the antifouling performance of five fouling-release (FR) coatings in laboratory, and field test was also assessed. The correlation of lab assay and field test was studied using Spearman's rank correlation test. The results show that the Spearman's coefficient (r_s) between lab assay and field static test is 0.975 (p = 0.005) for diatom and 0.949 (p = 0.014) for Ulva spore respectively, which are significant at the 95% probability level. This indicates that the lab static assays using diatom and Ulva spore have good agreement with field static test. For dynamic performance evaluation, the r_s between diatoms adhesion assay and field dynamic test is 0.894 (p = 0.041) while the r_s for Ulva spore is 0.289 (p = 0.638), indicating the lab dynamic assay with diatom is accordance with the field dynamic test. Therefore, diatom was used to evaluate the performance of coating materials which exhibits the satisfactory correlation and consistency between lab assessment and field test, confirming that diatom is an adapted evaluation organism to evaluate FR coatings.     

An Experimental Study on Binderless Briquetting of Low‐Rank Coals

The potential of binderless briquetting as a means of transforming low‐rank coals into low moisture high grade solid fuel products has been studied. Using two dried low‐rank coals, binderless briquettes with high mechanical strength have been successfully produced through mechanical compression. An increase in heating value was achieved as a result of moisture reduction in the briquettes compared to as‐received coals. The residue moisture content in the briquettes had a predominant effect on briquetting characteristics and there existed an optimum moisture content for the maximum briquettes strength. The chemical structure and wettability of binderless briquettes were analyzed using FTIR and contact angle measurement. The results showed that hydrophobicity and chemical structure significantly affected the briquette properties.     

Sequential Monitoring of Conditional Randomization Tests: Generalized Biased Coin Designs

Abstract

For the generalized biased coin class of randomization procedures, Smythe (1988 Smythe , R. T. ( 1988 ). Conditional Inference for Restricted Randomization Designs , Annals of Statistics 16 : 1155 – 1161 . [Google Scholar]) proved asymptotic normality of the conditional linear rank test. Clinical trialists often undertake interim analysis to determine whether to stop the trial early for a substantial treatment effect. In this article, we will set up one interim analysis using a conditional randomization test. The joint asymptotic distribution of the interim test statistic and the final test statistic will be explored. We also define the concept of conditional information under a randomization model.     

Asymptotics of Quantiles and Rank Scores in Nonlinear Time Series

This paper extends the concept of regression and autoregression quantiles and rank scores to a very general nonlinear time series model. The asymptotic linearizations of these nonlinear quantiles are then used to obtain the limiting distributions of a class of L-estimators of the parameters. In particular, the limiting distributions of the least absolute deviation estimator and trimmed estimators are obtained. These estimators turn out to be asymptotically more efficient than the widely used conditional least squares estimator for heavy-tailed error distributions. The results are applicable to linear and nonlinear regression and autoregressive models including self-exciting threshold autoregressive models with known threshold.     

区间统计量及其分布

提出区间统计量和区间秩统计量的概念,建立其概率密度函数和联合分布函数,给出区间统计量的均值、方差、协方差和区间秩统计量的平均秩、中位秩、百分位秩计算公式。区间统计量是对顺序统计量的补充,当失效数据较少难以统计分析时,可以通过区间统计量增加其数据,提高统计分析的精度。在此基础上,提出一种区间数据最佳线性无偏估计方法,并对正态分布、极值分布、Weibull分布等常用的位置一尺度分布进行讨论,该方法能够对产品贮存寿命进行小样本预测和可靠性评定。     

Experimental study on microwave drying of Chinese and Indonesian low-rank coals

Drying characteristics of low rank coals in a local microwave oven operating at 2.45 GHz were investigated. Effects of coal particle size, microwave power level, and coal sample size on drying characteristics were studied. Weight losses and temperature history of the samples were measured during drying. Drying rates were then obtained vs. drying time and moisture content. It was found that drying rate was increased with increasing coal particle size showing different trends from conventional drying methods reported in the literature. It was also observed that drying rate increased with increasing power output of the microwave oven or with decreasing coal sample weight. Effects of coal ash content and coal type were also investigated by comparing Chinese and Indonesian low rank coals. Ash content seems to be the governing factor in determining the drying characteristics for coal samples with small particle sizes. Drying mechanism of coals under microwave drying conditions was also discussed.     

微波场中长焰煤与焦煤共热解实验研究

对王家沟(WJG)长焰煤和焦煤(JM)两种原料煤进行了微波共热解实验研究,考察了两种煤配比不同时热解产物的收率及成分变化.结果表明,微波热解条件下,随着混煤中JM比例的增大,焦油收率在逐渐减少,而固体焦的灰分含量与硫含量逐渐增加.SEM照片也表明,固体焦表面的微孔结构越来越多,微孔的边界越来越清晰.煤气中CO2,CO,CH4和CnHm含量在3 min以前随热解时间的延长均逐渐增加,随后逐步减少.随着混煤中JM配比的增大,热解煤气中CO2和CO含量逐渐减少,但CH4和CnHm含量在3 min以前变化不是很明显,在3 min~15 min区间逐渐增加.