Prediction of ash content of unloaded coal based on a discrete element simulation

Based on analysis of regularity of stacking coal,discrete element simultaneous simulation is adopted to predict the process of unloading coal,which is proved to be effcient in the prediction of ash content.The results show that the altitude of new irregular coal is equal to the income coal volume divided by area of cabin.The distribution of infnitesimal flow velocity helps to induce the motion equation of infnitesimal element,which provides the mathematical model for computer simulation.Swarm,a computer programming language,is utilized in this study.Adaptive infnitesimal stacking algorithm helps settle the diffculties in attainment of infnitesimal elements.The result of simulation is similar to the actual situation,which can accurately predict the ash contents of current time and cumulative time.Coal movement in the cabin is a new project,the result of which can also be applied to other solid particles and the widespread of the result will be highly valued.

Calorific values and ash contents of different parts of Masson pine trees in southern China

Calorific value of plants is an important parameter for evaluating and indexing material cycles and energy conversion in forest ecosystems. Based on mensuration data of 150 sample sets, we analyzed the calorific value(CV) and ash content(AC) of different parts of Masson pine(Pinus massoniana) trees in southern China using hypothesis testing and regression analysis. CV and AC of different tree parts were almost significantly different(P<0.05). In descending order, ash-free calorific value(AFCV) ranked as foliage > branch > stem bark > root > stem wood, and AC ranked as foliage > stem bark > root > branch > stem wood. CV and AC of stem wood from the top, middle and lower sections of trees differed significantly. CV increased from the top to the lower sections of the trunk while AC decreased. Mean gross calorific value(GCV) and AFCV of aboveground parts were significantly higher than those of belowground parts(roots). The mean GCV, AFCV and AC of a whole tree of Masson pine were 21.54 kJ/g, 21.74 kJ/g and 0.90%, respectively. CV and AC of different tree parts were, to some extent, correlated with tree diameter, height and origin.

Preparation of activated carbon with low ash content and high specific surface area from coal in the presence of KOH

An activated carbon with ash content less than 10% and specific surface area more than 1 600 m 2 /g was prepared from coal and the effect of K containing compounds in preparation of coal based activated carbon was investigated in detail in this paper. KOH was used in co carbonization with coal, changes in graphitic crystallites in chars derived from carbonization of coal with and without KOH were analyzed by X ray diffraction (XRD) technique, activation rates of chars with different contents of K containing compounds were deduced, and resulting activated carbons were characterized by nitrogen adsorption isotherms at 77 K and iodine numbers. The results showed that the addition of KOH to the coal before carbonization can realize the intensive removal of inorganic matters from chars under mild conditions, especially the efficient removal of dispersive quartz, an extremely difficult separated mineral component in other processes else. Apart from this, KOH demonstrates a favorable effect in control over coal carbonization with the goal to form nongraphitizable isotropic carbon precursor, which is a necessary prerequisite for the formation and development of micro pores. However, the K containing compounds such as K 2 CO 3 and K 2 O remaining in chars after carbonization catalyze the reaction between carbon and steam in activation, which leads to the formation of macro pores. In the end an innovative method, in which KOH is added to coal before carbonization and K containing compounds are removed by acid washing after carbonization, was proposed for the synthesis of quality coal based activated carbon.

FAST MEASUREMENT OF ASH CONTENT IN COAL WASHING PLANT

The coal filter cake is a product of fine coal after floatation which has an ash content of 7-13%, water content of 30±2%, and a particle size of less than 1 mm. The ash content was measured by the intensity of the single backscattered gamma-ray, and its accuracy is mainly dependent on the energy of the gamma-ray. The 238Pu low energy photon source is selected in this work. The energy of its gamma-ray is 15 keV, which can result not only in the best sensitivity, but also in the lowest contribution to the environment radiation. The root mean square deviation of the ash measurement is±0.33% (±1σ).

Quality Evaluation of Yi Medicine "Qibujing" Based on Determination of Water Content and Ash Content

[Objectives]To determine the water content,total ash content and acid-insoluble ash content of Yi medicinal material"Qibujing",so as to provide experimental basis for establishing the Quality Standard(Draft)of Yi Medicinal Material"Qibujing"in Sichuan Province.[Methods]According to the second method(drying method)in 0832 water content determination method and 2301 ash content determination method in Chinese Pharmacopoeia(2015 Edition),it was determined,respectively,and the data were processed by IBM SPSS Statistics 26 and DPS 7.05 data processing system.[Results]All the 14 batches of sample met the stipulation that the water content should not exceed 12.0%,the total ash content should not exceed 8.0%,and the acid-insoluble ash content should not exceed 1.5%under"Guan Zhong-(Qibujing)"in the 2005 edition of Yunnan Traditional Chinese Medicine Standard.There was a negative correlation between water content,acid-insoluble ash content and altitude,and a positive correlation between total ash content and altitude.[Conclusions]It is suggested that Quality Standard(Draft)of Yi Medicinal Material"Qibujing"in Sichuan Province stipulate that the water content should not exceed 12.0%,the total ash content should not exceed 8.0%,and the acid-insoluble ash content should not exceed 1.5%.

Determination of Moisture, Ash, Extract Content and TLC identification of Tibetan Medicinal Material Dracocephalum tanguticum Maxim.

[Objectives] The moisture, ash and extract content of Dracocephalum tanguticum Maxim. were measured.[Methods] The moisture, total ash, acid-insoluble ash and extract content of D. tanguticum Maxim collected from 16 producing areas were detected by using the methods in Chinese Pharmacopoeia (2015 edition, volume I), and D. tanguticum Maxim. was identified by thin layer chromatography in Chinese Pharmacopoeia (2015 edition, volume I).[Results] The moisture content of D. tanguticum Maxim collected from 16 producing areas ranged from 8.68% to 10.36%, averaging 9.28%. The content of total ash was between 7.21% and 11.60%, averaging 9.89%. The content of acid-insoluble ash was 0.21%-2.71%, averaging 1.51%. The extract content (water-soluble) was 26.67%-42.91%, averaging 32.65%. According to the results of TLC identification, the 16 samples and reference substance had the same characteristic spots at the corresponding positions.[Conclusions] It was recommended that the moisture, total ash and acid-insolue ash content of D. tanguticum Maxim were not be more than 11%, 12%, and 3% respectively, while the extract content was not less than 26%. It provides reference for filling the gaps in the quality standards of D. tanguticum Maxim.

Evaluation of Wild Paeonia veitchii Lynch from Sichuan Based on Moisture, Ash and Extract Contents

[Objectives]The research aimed to determine the contents of moisture,ash and extract of wild Paeonia veitchii Lynch produced in Sichuan,so as to provide the basis for evaluating quality of wild P.veitchii Lynch from Sichuan.[Methods]Moisture,ash and extract contents of wild P.veitchii Lynch were respectively determined according to the fourth part of the Chinese Pharmacopoeia of 2015 version,and correlation analysis and TOPSIS analysis were used for data processing.[Results]12 batches of samples all corresponded with the provision that moisture of P.veitchii Lynch should not exceed 14.0%in the Standard of Traditional Chinese Medicine in Sichuan Province of 2010 version;11 batches of samples all corresponded with the provisions that total ash and acid insoluble ash of P.veitchii Lynch should not exceed 7.0%and 1.0%in the Standard of Traditional Chinese Medicine in Sichuan Province of 2010 version;average content of alcohol-soluble extract by hot dipping from 12 batches of samples was 42.29%,which was not less than 30.0%.In P.veitchii Lynch,moisture and acid insoluble ash showed positive correlation with altitude,while total ash and extract content were negatively correlated with altitude.Taking moisture,ash and extract as evaluation indexes,No.9 P.veitchii Lynch sample was the best.[Conclusions]Moisture and ash of P.veitchii Lynch corresponded with the provisions of the Chinese Pharmacopoeia of 2015 version and the Standard of Traditional Chinese Medicine in Sichuan Province of 2010 version,while extract content was higher than provision of the standard.The research could provide reference basis for rational utilization and quality evaluation of P.veitchii Lynch resources.

Quality Evaluation of Leontopodium franchetii Beauv. from Different Localities Based on Moisture,Ash and Extract Contents and Thin-layer Chromatography

[Objectives] The aim was to determine the moisture,ash and extract contents in Leontopodium franchetii Beauv. from different localities. [Methods] The contents of moisture,total ash,acid-insoluble ash and extract in L. franchetii from different localities were determined according to the methods described in Chinese Pharmacopoeia( 2015 Edition). [Results] In the 10 samples,the contents of moisture were all less than or equal to 15. 0%; the contents of total ash were all below 12. 0%; and the contents of acid-insoluble ash were all less than 3. 0%. The contents of water-soluble extract( by cold-soaked extraction method) in the samples were all below 12. 0% except those from Hongyuan Prairie of Sichuan Province and Xinglong Mountain in Lanzhou City,Gansu Province. [Conclusions]The contents of the four indicators measured in this experiment varied by small margins,indicating that the quality was relatively stable. This study provides theoretical data for the revision of the quality standards for L. franchetii.

基于数据生命周期的煤泥浮选智能控制技术研究进展

随着国家政策和新一代人工智能技术的持续牵引,矿山智能化研究取得突破,其中,选煤厂智能化建设受到高度关注,煤泥浮选智能控制技术一直是阻碍选煤厂智能化建设的关键瓶颈之一。以煤泥浮选数据生命周期为主线,从浮选精煤/尾煤灰分在线预测、浮选药剂智能添加和煤泥浮选系统智能决策3个角度综述了煤泥浮选智能控制技术的研究进展,并展望未来煤泥浮选智能控制技术发展趋势。浮选精煤灰分在线预测困难重重,单一视觉特征信息并不可靠,尾矿灰分的预测技术相对更加成熟可靠;浮选药剂添加量受多个过程变量同时制约,模型性能在整个工况区间的自适应性和泛化能力还需进一步提升;当前浮选工业系统智能控制技术的进一步发展严重受限于浮选精煤/尾煤灰分等指标的预测精度、传感器检测精度、药剂添加精度等因素。浮选过程数据集维度更高,难以建立可靠的知识库,以深度学习为代表的新一代人工智能技术能适应这类数据结构。此外,已有浮选监测系统只针对特定矿物,唯一性较高。未来浮选智能控制系统应集中攻克指标预测、传感器检测精度等方面限制,建立多煤种、模板化的煤泥浮选智能控制资料大数据集和大模型。

改良垃圾焚烧底渣固化疏浚淤泥性能试验研究

基于以废治废理念,提出了用改良垃圾焚烧底渣固化疏浚淤泥的新思路,并开展了室内试验研究,测定了固化淤泥试样的含水率、无侧限抗压强度及抗剪强度指标。试验结果表明:垃圾焚烧底渣磨细粉和未研磨的原渣按1∶1比例混合时,具有最优的固化性能;在最优混合比条件下,固化淤泥的无侧限抗压强度、黏聚力和内摩擦角均随龄期和改良垃圾焚烧底渣掺入比的增加而增大,含水率则相反;当改良垃圾焚烧底渣掺入比为35%时,固化淤泥28 d无侧限抗压强度达到了58.4 kPa,含水率由67.4%降至38.0%,采用改良垃圾焚烧底渣固化疏浚淤泥是可行的。

变异系数法-AHP复合加权联用TOPSIS模型优选白附片降毒增效炮制工艺

目的:运用变异系数法-层次分析法(AHP)复合加权联用TOPSIS优选白附片炮制工艺参数,为白附片规范化炮制提供参考。方法:以煮制时间、浸漂时间和蒸制时间为考察因素,以穷举寻根法开展试验设计,以苯甲酰新乌头原碱、苯甲酰乌头原碱、苯甲酰次乌头原碱、新乌头碱、次乌头碱、乌头碱、水分、灰分和胆巴残留量为评价指标,以变异系数法-AHP复合加权计算权重系数,通过TOPSIS模型优选白附片炮制工艺参数。结果:白附片最优炮制工艺参数为煮制20 min、浸漂48 h、蒸制3 h。结论:该工艺稳定、可行,可为白附片的规模化加工炮制提供参考。

粉煤灰掺量对全再生自密实混凝土工作性能与力学性能的影响

本文使用再生粗骨料全部替代天然粗骨料,用粉煤灰分别替代20%、30%、40%、50%和70%(质量分数)水泥,制备了不同水胶比(0.36、0.40和0.45)的全再生自密实混凝土,通过抗折强度试验和抗压强度试验,分析了粉煤灰掺量和水胶比对全再生自密实混凝土性能的影响规律,得到了粉煤灰的合理掺量,提出了适用于全再生自密实混凝土抗折强度的计算公式。结果表明:当粉煤灰掺量由20%增至40%时,所有全再生自密实混凝土拌合物的坍落扩展度呈先增加后降低趋势,且均表现出良好的间隙通过能力,但混凝土拌合物扩展时间T_(500)受粉煤灰的影响不显著;随着粉煤灰掺量增加,全再生自密实混凝土的抗压强度和抗折强度均呈先增加后降低趋势,抗折强度受粉煤灰掺量的影响程度要高于抗压强度;全再生自密实混凝土抗压强度和抗折强度受水胶比的影响程度相同;综合粉煤灰掺量对全再生自密实混凝土工作性能和力学性能的影响,建议粉煤灰对水泥的取代率为30%。

粉煤灰不同掺量对高性能混凝土耐久性影响研究

为了研究粉煤灰掺量对高性能混凝土材料耐久性影响,在P·O42.5级高性能混凝土中掺入10%、20%、30%、50%的粉煤灰。设计混凝土、粉煤灰掺量的试验配合比,将粉煤灰掺量和高性能混凝土配合比作为正交试验的2个变量。试验结果表明,正常环境下10%、20%、30%时的混凝土渗透率较低,抗压强度大,50%的混凝土渗透率较高且抗压强度有所减小,冻融环境下的各个数据值均小于正常环境,说明适量掺入粉煤灰掺量能够提高混凝土材料耐久性。通过对试验数据整理可知,使用所研究方法混凝土渗透率、抗压强度与统计数据均存在最大仅为1%和0.1 MPa的误差,能够将试验研究结果作为实际工程可行的条件。

600 MW对冲燃烧锅炉分磨掺烧煤粉燃尽特性的模拟和试验研究

针对亚临界600 MW自然循环对冲燃烧锅炉燃用3种差异性较大的煤种,通过数值模拟结合现场试验研究了分磨配煤掺烧对降低飞灰含碳量的作用机制,建立了对冲锅炉分层燃烧混煤的燃料特性与燃尽率、飞灰含碳量的关联性,并提出了改善电站锅炉中煤粉燃尽特性的配煤原则。首先设定了3种极端的工况,以优质煤为主分别集中在燃烧器的上、中、下3层燃烧器中进行燃烧;再通过计算流体动力学(computational fluid dynamics,CFD)模拟发现优质煤在上层燃烧器分布且劣质煤在下层分布时,劣质煤在炉内的停留时间显著增加,其在上层高温区充分燃烧,飞灰含碳量低。同时,根据不同工况下各层燃烧器煤粉的热值、挥发分、灰分进行分析,发现热值差异性是影响其燃尽特性的主要影响因素;然后基于燃煤电厂实际运行条件,设置了更切合实际的配煤工况,并进行了数值模拟与现场试试验研究,发现各工况下呈现的煤粉总体燃尽特性符合上述规律,飞灰含碳量相比于电厂原始运行工况下降。最后得到配煤原则为:在充分考虑电厂实际运行条件的情况下,将高热值的煤种向中、上层燃烧器布置,而低热值的煤种向中、下层燃烧器分布。

循环流化床锅炉降低灰渣含碳量热态试验研究

针对循环流化床(CFB)锅炉燃用非设计煤种工况下,对总风量、一/二次风比例、床温、床压等参数进行热态调整试验,分析各参数对锅炉飞灰及底渣含碳量的影响规律。结果表明:在330 t/h负荷的基准工况下(不投飞灰再循环),通过适当提升床压及燃烧室温度,能使燃料充分燃烧,飞灰含碳量由调整前最高20.75%减少到15.97%左右,底渣含碳量从最高2.28%降低至0.40%左右,锅炉效率提高约1.5%以上。此外,飞灰再循环的投入能有效降低飞灰含碳量,建议在生产实践中尽量保证飞灰再循环的连续投入。

灰分指标在PVC-U管材标准中的设立探讨

研究了硬聚氯乙烯(PVC-U)管材灰分指标的测定方法及其在产品标准中的应用。结果表明:在相同灼烧条件下,不同种类PVC-U管材用无机填料的失重率各不相同。不能只依据灰分推导PVC-U管材的填充材料用量和力学性能变化。以灰分指标为代用指标缺乏可靠性,灰分限量值设定无法提升产品质量,对产品质量控制产生干扰作用,且GB/T 5836.1—2018《建筑排水用硬聚氯乙烯(PVC-U)管材》现有力学性能指标作为直接性能指标能够满足PVC-U管材的使用性能要求,没有必要增加灰分指标。

粉煤灰对混凝土抗渗性能的影响规律研究

为分析粉煤灰掺量与混凝土抗渗性能之间的关系,文中开展了粉煤灰掺量及养护龄期对混凝土抗压强度、孔隙率、渗水高度、渗水压力以及氯离子渗透系数的影响研究。结果表明,混凝土早期抗压强度、渗水高度及抗氯离子渗透系数随着粉煤灰掺量的增加而降低,渗水压力及孔隙率随着粉煤灰掺量的增加而降低。当粉煤灰掺量为25%时,混凝土抗压强度、孔隙率、渗水压力、渗水高度及抗氯离子渗透系数均达到最佳。所有类型混凝土抗压强度、孔隙率、渗水压力、渗水高度及抗氯离子渗透系数均随着养护龄期的增加而增强,早期性能的变化速率远远超过后期性能的变化速率。

基于高精度传感器设计的跳汰机浮标运动特性研究

跳汰机浮标运动特性能精准反映跳汰机床层厚度且能预判洗选精煤质量,可指导跳汰选煤过程高效进行。基于超声波测距技术开发新型跳汰机床层厚度传感器,试验探究浮标位置和浮标密度对浮标运动特性的影响程度。结果表明,浮标密度对应床层厚度的最小回归参数为0.710,跳汰机浮标运动特性受浮标密度影响强烈;浮标密度的增加导致浮标运动上下位移峰值差异较大,运动位移上限为8.17~13.67 cm、下限为2.17~6.50 cm;浮标位置影响下的浮标运动位移上限值变化区间和下限制变化区间不大,浮标位置对床层厚度的最大回归参数仅为0.186,浮标运动较为稳定。在九里山矿选煤厂的实际应用中,基于浮标运动位移的监控有效地控制了洗选精煤灰分在9.02%~9.12%,灰分极差仅为0.10%,比应用前波动范围缩小45%,进一步证实自制的高精度传感器能够有效提高精煤质量,对于推进跳汰选煤自动化技术具有积极意义。

粉煤灰对孔道压浆料稳定性的影响分析

粉煤灰是孔道压浆料中应用最广泛的矿物掺合料。该文通过对孔道压浆料生产过程中不同批次粉煤灰配比调整过程进行研究,并通过试验总结粉煤灰掺量、密度对孔道压浆料性能影响。结果表明,粉煤灰对孔道压浆料流动性有促进作用,掺量越高流动度促进效果越强;粉煤灰掺量过高会导致孔道压浆料凝结时间增长,强度降低,最大掺量不宜大于25%;粉煤灰掺量过高或过低会导致在孔道压浆料浆液中部分上浮或沉淀,影响孔道压浆料浆液稳定性;粉煤灰的密度影响在孔道压浆料中的适宜掺量,密度越大,适宜掺量越低。