发热量回归式在低热值煤发电中的应用

<正> 随着煤炭综合利用事业的不断发展,我国煤炭系统建起了大批低热值煤发电厂。电厂所用燃料主要是矿山生产过程中产生的脏杂煤、低质原煤、洗煤副产品等,通过配合加工,可使配后煤的应用基低位发热量 Q_(net,ar)达到10.454～11.708MJ/kg。为了保证配煤的发热量,必须随时掌握原料煤及配煤的发热量情况。而每批分别测定原料煤及配后煤的发热量很麻烦,也不能及时获得结果。通过实践,用发热量的回归方程式可有效地指导配煤,并对入炉煤的热值情况进行监测,做到科学管理。本文以我局永荣电厂为例,谈谈发热量回归式在低热值煤发电中的应用。     

烟煤1％外水对其收到基低位发热量的影响

从煤1％含水量对其收到基低位发热量影响问题的发现和提出，探讨烟煤1％外水对煤收到基低位发热量的影响并加以应用。     

原煤低位发热量的计算机计算

本文介绍了从工业分析数据出发计算各种煤低位发热量的计算方法;编制了进行此项计算的BASIC程序;列举了应用实例。运用该程序,只要输入煤的工业分析数据,毋需查取任何表格,计算机便可立时键出分析基低位发热量的值。如需计算应用基低位发热量,应再输入应用基水份重量百分含量,即得结果。     

对烟煤分析基低位发热量的经验公式的探讨

我厂是一家回转窑水泥企业,产品有普通硅酸盐水泥、矿渣水泥和白水泥.所用燃料为烟煤,其工业分析按GB212-91执行,低位发热量的计算按<地方水泥企业化验室手册>中规定:各种煤的热值计算,统一使用煤研院近几年提出的新公式.计算烟煤分析基低位发热量的经验公式:     

浅谈全水分、氢值对动力煤应用基低位发热量计价的影响

通过对贵州省内10家火电厂汽车煤应用基低位发热量计价的实际运作,讨论煤中全水分、氢值在计价中的作用.     

2014年1月国内煤炭价格走势分析

<正>2014年1月,国内动力煤市场弱势运行。煤矿出货正常,但销售一般。部分港口报价如下:秦皇岛港动力煤弱势下行,发热量22.99 MJ/kg动力煤报价575~585元/t;广州港印尼煤发热量22.57 MJ/kg报价610~620元/t,山西大混煤发热量20.06MJ/kg报价585~595元/t、发热量20.90 MJ/kg报价600~610元/t,内蒙古优混煤发热量22.99 MJ/kg报价690~700元/t。     

金桥热电厂锅炉燃烧优化调整及经济分析

金桥热电厂目前实际燃煤变化较大,与锅炉设计煤种存在一定的偏差(设计煤种低位发热量为20.06MJ/kg,实际燃煤低位发热量14MJ/kg)。根据节能降耗工作安排,为适应煤种变化,对锅炉燃烧系统与制粉系统进行全面系统的优化调整,掌握锅炉制粉系统和燃烧系统的的运行特性,对影响锅炉能耗的原因进行定量的经济分析。通过锅炉燃烧与制粉系统优化调整,充分挖掘锅炉节能降耗的潜力,确定目前实际燃用煤种的最佳运行方式,提高锅炉运行的安全及经济性。     

煤中全水分的测定

煤中全水分是炼焦精煤中一项重要的计价指标,中国动力用煤采用收到基低位发热量计价,每增加1％的全水分将会使发热量降低260J／g左右。准确测定煤中全水分,可减少煤炭供需双方的质量纠纷,使煤炭按质计价更科学、公正、公平,在煤炭按质计价中起到举足轻重的作用。根据多年的实践经验,提出准确测定煤中全水分可行的操作方法,以避免煤炭供需双方产生不必要的质量争议。     

影响煤炭发热量测定准确性的因素分析

依据GB/T 213-2008《煤的发热量测定方法》,结合煤炭发热量检测中实际工作经验,从热容量标定、称样量、与收到基低位发热量计算有关的检测项目及环境控制等分析了影响煤炭发热量测定准确性的影响因素,并提出相应的预防措施和对策。     

关于煤炭发热量表达形式的探讨

针对用户对煤炭发热量理解方面存在的问题 ,为了更科学地评价煤炭发热量 ,提出了标准态和生产态的概念 ,即标准收到基低位发热量、标准空气干燥基高位发热量、标准空气干燥基低位发热量和生产态收到基低位发热量 ,认为用标准收到基低位发热量Q0net,ar和生产态收到基低位发热量Q net,ar来评价煤炭质量比较合理。     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

典型煤碳燃烧特性研究和数值模拟

本文以三种典型煤的碳燃烧为研究对象，分别采用简单一维沉降燃烧方式和等温加热燃烧方式，实验研究了煤在快速加热条件下，其碳的初期和中，后期燃烧过程。以实验为基础，建立了煤的碳燃烧模型，变工况数值模拟了煤的碳燃烧过程，揭示了煤不同条件下的单颗粒碳燃烧特性。     

用两个形状指数表征粉煤灰颗粒形貌的研究

引用两个形状指数表征颗粒形状的概念,即先将颗粒形状近似为椭圆,再将椭圆图像分离:以圆为基准的颗粒宏观形状指数δ;以光滑椭圆为基准的颗粒轮廓凹凸度,即微观形状指数ζ。分析和发展了近似椭圆模型。并运用图像分析仪对粉煤灰、水泥样品进行实验。结果表明,粉煤灰颗粒的两个形状指数δ和ζ都大于水泥颗粒。证明粉煤灰颗粒的球形度、表面光滑度优于水泥,而且,随着粒径增大,δ和ζ呈下降趋势,表明磨制颗粒越粗。(?)粒形状越不规则。文中还运用近似椭圆模型再现了颗粒的模拟图像。     

酚醛树脂热降解动力学研究

用热失重非等温法对不同甲醛,苯酚魔鬼洋比的酚树脂进行了热降解动力学研究。结果表明,甲醛,苯酚摩尔比为１．５时,酚醛树旨的热发活化能最高。耐热性最好。