【作者】 焦有宙；

【导师】 骆仲泱； 倪明江； 岑可法；

【作者基本信息】 浙江大学 ， 工程热物理， 2008， 博士

【摘要】 燃煤电力工业在向社会提供洁净电力的同时，其产生的巨量粉煤灰对环境和生态造成了巨大压力。开展粉煤灰综合利用研究，实现粉煤灰资源化、减量化和效益化，成为缓解环境生态压力，解决资源短缺矛盾的重要举措。目前开展的煤粉炉联产水泥熟料技术研究，其创新之处在于将燃煤电力工业与水泥工业纳入循环经济环节，实现粉煤灰的源利用。为了科学合理的确定煤粉炉联产水泥熟料的系列和品种。本文在分析煤粉炉联产水泥熟料技术研究现状基础之上，对不同种类水泥及其熟料的原料特点、烧成条件、化学组成、矿物种类和水化特性开展了比较分析，对煤灰成分与水泥硅铝质原料的化学组成特点进行了对照分析，对煤粉炉联产硅酸盐、铝酸盐和硫铝酸盐等传统水泥熟料存在的问题进行了理论分析。将具有低碱度、低烧成温度和良好水化性能的Q相矿物引入煤粉炉联产水泥熟料技术，提出了煤粉炉联产Q相水泥熟料的试验构想，按照煤质特性拟定了煤粉炉联产Q相水泥熟料的分类原则。为了探寻Q相矿物的形成机制，本文在实验室高温炉开展了钙铝黄长石2CaO·Al₂O₃·SiO₂转变为Q相矿物的试验研究，并以此为基础，在模拟煤粉炉的两段多相反应实验台，以长广煤和兖州煤为试验煤种，进行了煤粉炉联产改性粉煤灰矿物生成规律试验研究。试验结果表明：2CaO·Al₂O₃·SiO₂能与适量CaO和MgO反应生成具有良好水化活性的Q相矿物；高硫长广煤和低硫兖州煤，随其混合煤粉添加剂质量分数的调整，改性粉煤灰矿物组成由非活性成分占主体，逐渐过渡为矿物组成出现少量水泥熟料矿物，直至矿物组成由水泥熟料矿物占主体且出现目标矿物Q相。改性粉煤灰矿物生成规律试验结果，验证了高硫煤和低硫煤联产Q相水泥熟料的可行性。为了获得煤粉炉联产Q相水泥熟料煅烧制度，本文选取长广煤为试验煤种，在两段多相反应实验台，开展了煅烧温度、物料停留时间、混合煤粉制备方式、炉内气氛和钙基添加剂形式等影响因素试验研究。试验结果表明：在本试验研究条件下，实验台炉内温度设定为1 330℃，物料在炉内停留6．94s是熟料矿物烧成反应的最佳条件，熟料矿物生成反应较为充分；在一定范围内，煤粉与添加剂粒度越小、粒度筛分级差越大，愈有利于混合煤粉中矿物质与添加剂发生水泥熟料矿物生成反应；高硫煤联产Q相水泥熟料，炉内还原性气氛对熟料矿物3CaO·3Al₂O₃·CaSO₄的生成反应产生负面影响，而对Q相矿物的生成反应有促进作用；用CaCO₃替代CaO配料联产Q相水泥熟料，熟料矿物组成中有Q相矿物存在，但熟料矿物生成反应不彻底，还需进一步开展煤粉炉联产Q相水泥熟料钙基添加剂形式及掺加工艺的研究。为了判断煤粉炉联产Q相水泥熟料对锅炉系统运行可能产生的影响，本文以长广煤和兖州煤为试验煤种，开展了混合煤粉燃烧及熔融特性试验研究。试验结果表明：随着添加剂比例的增加，混合煤粉燃烧热失重速率曲线相对原状煤粉而言交得愈为平缓；混合煤粉燃烧速率降低，燃烧明显分为两个阶段，且燃烧后移趋势增大；混合煤粉着火温度提高，着火延迟时间变长，稳定性降低；混合煤粉放热量减少，燃尽时间延长。混合煤粉灰熔融特性试验结果表明：随添加剂CaO质量分数在一定范围内的逐渐增加，混合煤粉熔融特性温度呈现V型变化规律；长广煤和兖州煤联产Q相水泥熟料，其结渣趋势较原状煤都有一定程度的降低。对混合煤粉煤灰软化温度矿物组成进行了XRD分析，并利用CaO-Al₂O₃-SiO₂三元系统相图，对煤灰熔融特性温度变化规律开展了机理分析。分析表明，随着混合煤粉添加剂质量分数变化，煤灰矿物组成中出现低温共融体是煤灰熔融特性温度降低的主要原因。本文对长广煤和兖州煤联产熟料样品矿物组成进行了XRD定量分析，结果显示联产熟料样品矿物组成以2CaO·SiO₂和Q相为主。长广煤和兖州煤联产熟料样品2CaO·SiO₂的质量分数分别为57．2％和46％，Q相矿物质量分数分别为27．2％和32．1％。考虑到熟料样品矿物组成中贝利特和Q相矿物的双重特性，本文将联产熟料定位为贝利特-Q相水泥熟料。联产贝利特-Q相水泥熟料砂浆强度试验结果表明，其砂浆试样各龄期抗压强度和抗折强度接近32．5普通硅酸盐水泥标准；当联产贝利特-Q相水泥熟料中掺入30％的硅酸盐水泥熟料时，其砂浆试样各龄期强度超过了32．5普通硅酸盐水泥标准；联产贝利特-Q相水泥熟料膨胀性能、安定性和凝结时间符合水泥产品相关标准。联产贝利特-Q相水泥熟料，水化3d就出现2CaO·Al₂O₃·8H₂O、3CaO·Al₂O₃·3CaSO₄·32H₂O、xCaO·SiO₂·yH₂O和Al₂O₃·3H₂O等水化产物。且随着水化龄期的延长，2CaO·Al₂O₃·8H₂O、3CaO·Al₂O₃·CaSO₄·12H₂ O、3CaO·Al₂O₃·6H₂O等水化产物逐渐占据主体。煤粉炉联产贝利特-Q相水泥熟料能兼收一定的固硫效果，熟料样品游离CaO质量分数符合水泥熟料产品标准。本文在混合煤粉球形聚合颗粒假设前提下，将煤粉炉联产贝利特-Q相水泥熟料过程简化为混合煤粉球形聚合颗粒灰化过程。对煤中矿物质高温热反应行为，以及长广煤和兖州煤联产贝利特-Q相水泥熟料化学组成进行了分析研究。依据经验公式，对Q相矿物热力学数据进行了估算。对长广煤和兖州煤联产贝利特-Q相水泥熟料化学组成可能发生的矿物生成反应进行了热力学计算，对熟料矿物生成反应优先顺序进行了比较，对可能生成的熟料矿物种类进行了理论分析。联产熟料化学组成矿物生成反应热力学分析结论，与长广煤和兖州煤联产试验熟料矿物组成事实基本一致。采用金斯特林格方程对长广煤和兖州煤联产贝利特-Q相水泥熟料过程进行了动力学分析。初步确立了长广煤和兖州煤联产贝利特-Q相水泥熟料矿物形成化学。本文以一台330MW机组1 004(t．h^-1)煤粉炉为对象，对其实施联产贝利特-Q相水泥熟料技术可能产生的经济、资源和能源效益进行了初步分析。结果表明：此锅炉实施联产贝利特-Q相水泥熟料技术，可给电力企业和水泥企业年创造经济效益6 658万元；水泥企业可年节约黏土质原料7．66万t，节约水泥混合材8．62万t；可年降低能源消耗2．024万t标准煤。更多还原

【Abstract】 While coal-fired power industry provides our society with clean electric power, the generation of jillion fly ash confronts us with pressure from deterioration of environment. Study on comprehensive utilization and realization of resource, reduction and benefit of fly ash become ways and means of mitigation of environment pressure and shortage of nature resource. The innovation of coproduction technology of cement clinker in PPC （pulverized coal combustion） boilers of power plants, lie in achievement of source utilization of fly ash , realization of circular economy between coal-fired power industry and cement industry and breakthrough of impasse of traditional utilization of fly ash.In order to select reasonable series and types of coproduction cement clinker in PPC boilers, based on status analyses of coproduction technology of cement clinker, comparison of raw material characteristics, calcinations condition, chemical composition,mineral component and hydration performance were carried out between different series of cement and clinker, and the properties and difference between minerals in coal ash and silicon -aluminum raw materials of cement were analyzed. Problem of coproduction of traditional cement were analyzed. Then,Q-phase with low alkalinity,low calcinations temperature and better hydration performance was introduced to coproduction technology of cement clinker. In this dissertation, the idea was originally put forward to cogenerate Q-phase cement clinker in PPC boilers, and the sort principle of coproduction of Q-phase cement clinker was primarily designed according to properties of coals.In order to ascertain formation mechanism of Q-phase in the process of cement clinker coproduction, experiments of transform of pure mineral of 2CaO·Al₂O₃·SiO₂ into Q phase were conducted on high-temperature box-type resistance furnace.Then,on the base of experiment results, high-sulphur Changguang coal and low-sulphur Yanzhou coal selected as experimental coals, experiments of mineral formation law of calcium-enriched modified fly ash were performed on two-stage polyphase reaction setup. The collected samples were analyzed by XRD, SEM and EDS,respectively. The results displayed that pure 2CaO·Al₂ O₃·SiO₂ with suitable content CaO and MgO could transform into Q phase; Wheather Changguang coal or Yanzhou coal, with adjustment of addtives content in agglomeration coal powder, minerals component of coproduction modified fly ash varied from mainly con sisting of no-active minerals gradually to appearance of trifling cement clinker minerals, to appearance of cement clinker and aim mineral of Q-phase. Experiments results testified the feasibility of coproduction of Q-phase cement clinker from high-sulphur Changguang coal and low-sulphur Yanzhou coal.High-sulphur Changguang coal as experimental coal, experiments of influencing factors such as calcinations temperature, material retention time, agglomeration coal powder preparation method and atmosphere in furnace on Q-phase cement clinker coproduction were performed on two-stage polyphase reaction setup. The results showed that under con dition of parameters of setup in this experiment, the best calcinations temperature was 1 3 30℃that was in accordance with temperature scope of pulverized coal combustion boilers; Under 1 330℃, at the range of 1.74 second to 6.94 second , extension of material retention time favored Q-phase cement clinker calcinations reaction; At a certain degree, the smaller particle of coal powder and calcium-base additive in agglomeration particles, the greater difference of sieving grade of coal powder and calcium-base additive in agglomeration particles, the easier solid reaction of CaO, MgO and minerals of coal powder took place in the process of combustion of agglomeration particle;Reducing atmosphere in furnace impact negative effect on formation of 3CaO·3Al₂O₃·CaSO₄, while formation of Q-phase can be promoted. With CaCO₃ replacing CaO,there was chance of formation of Q-phase.But increase of the ratio of none-combustible additives in agglomeration coal powder would give rise to heat value decrease,and the reaction of clinker minerals unsufficient. So further study on selection and addition technology of additive agent needs to do .With high-sulphur Changguang coal and low-sulphur Yanzhou coal selected as experimental coals, experiments of combustion characteristics and fusibility of agglomeration coal powder were investigated, The thermogravimetry results revealed that after adding calcium-based additives, the samples’ curve of mass loss become gentle with the increasing ratio of additives in the samples;The velocity of mass loss curves’ peak value fall, which showed the speed of loss weight went into slowly;the combustion process obviously sepa rated into two stages, and with the increasing of the ratio of additives, the burning intensity of the experiod was weakened gradually and in the anaphase the burning intensity was strengthened; the test sampler’s ignition temperatures somewhat increased, the kindling retention time prolonged, and the stability of combustion decreased. With the additive ratio increasing, the inter mixture’s convert ash ratio augmented, and the exotherm’s width of peak get narrow, and the value of calorific power trailed off, and the time of burnout were postponed. The fusion characteristics expriment results showed that with addition of CaO gradually increasing from zero to certain degree, melting characteristics temperature of agglomeration coal powder present variation law of V type. Compared with original Changguang coal and Yanzhou coal, slagging tendency of agglomeration coal powder for coproduction of Q-phase cement clinker was mild. Thermal reaction of minerals of coal ash in pulverized coal combustion boilers were simulated in high-temperature box-type re sistance furnace. Mineral components of coal ash at soft temperature were analyzed by X-ray diffraction, and further theoretically analysis of variation mechanism of melting characteristics temperature of agglomeration coal powder was conducted making use of ternary phase diagram of CaO-Al₂O₃-SiO₂ system .The results showed that with content of CaO and MgO added into agglomeration coal powder varying, existence of co-melting com pound in mineral components of agglomeration coal powder ash gave rise to decreasing of melting characteristics temperature.Experiments of Q-phase cement clinker coproduction were conducted on two-stage polyphase reaction setup under optimized calcination condition. High-sulphur Changguang coal and low-sulphur Yanzhou coal selected as experimental coals, and the collected clinker samples were quantitatively analyzed by X-ray diffraction. The results showed that the minerals components of cement clinker mostly consisted of 2CaO·SiO₂ and Q-phase, and the content of 2CaO·SiO₂ of cement clinker accounted for 57.2% and 46%, and the content of Q-phase of cement clinker accounted for 27.2% and 32.1% . According to minerals components of cement clinker, dual performance of 2CaO·SiO₂ and Q-phase of cement clinker coproduction were fully taken into account. The sample can be named "belite-Q phase cement clinker". The properties of coproduction cement clinker from Changguang coal were tested at measurement laboratory of Zhejiang Zhuji Fuli Cement Co., Ltd. The results indicated that strength of compress and flexiblity of mortar samples at different ages were close to national standard of 32.5 grades Portland cement; when 30 percent Portland cement clinker was added to belite Q-phase cement clinker, strength of compress and flexiblity of mortar samples at different ages exceeded national standard of 32.5 grades Portland cement. Dry shrinkage, setting time and invariability of belite Q-phase cement clinker all satisfied involved national standard of cement clinker. Apart from 2CaO·SiO₂, 2CaO·Al₂O₃·8H₂O crystal, 3CaO·Al₂O₃·3CaSO₄·32H₂O, xCaO·SiO₂·yH₂O gel, and Al₂O₃·3H₂O gel appeared in 3d hydration sample. With hydration process developing, hydration product of 2Ca O·Al₂O₃·8H₂O, 3CaO·Al₂O₃CaSO₄·12H₂O, 3CaO·Al₂O₃·6H₂O gradually enriched.The content of sulfur and free CaO of coproduction cement clinker were measure ed.The results showed that when pulverized coal combustion boilers coproduced belite Q-phase cement clinker, desulfurization efficiency in furnace can be simultaneously enhanced; and the content of free CaO of coproduction cement clinker amounted about to 1 %, meet ing the national standard of cement clinker.Based on the assumption of spherical aggregation particle of agglomeration coal powder, process analysis of coproduction of belite Q-phase cement clinker was reduced to analysis of spherical aggregation particle ashing. Dehydration and decomposition reaction of minerals of coal under high temperature were analyzed, and the chemical composition of cement clinker coproduction from high-sulphur Changguang coal and low-sulphur Yanzhou coal were preliminary investigated. By means of empirical equation, thermo dynamic parameters of Q-phase were estimated. In the light of thermodynamic function of state Gibbs free enthalpy, the free enthalpy variation of mineral formation reactions taking placing in process of coproduction of belite Q-phase cement clinker from Changguang coal and Yanzhou coal were calculated, and the sequence of priority of mineral formation reactions were found out, and the resultants in process of coproduction of belite Q-phase cement clinker were investigated. The analysis conclusion accorded with experiment results of belite Q-phase cogeneration from Changguang coal and Yanzhou coal. Making use of Gentling equation, kinetics analyses of coproduction of belite Q-phase were carried out. Mineral formation chemical of beliet Q-phase cement clinker coproduction from Changguang coal andYanzhou coal were preliminary set up.Last but not least,the benifts of coal-fired power enterprise and cement enterprise were predicted by micro-case method ,one year as analytical period, one 1 004 (t.h^-1) PPC boiler for 330MW power set selected as analyzed object. The analyses showed direct profits of 66 580 000 yuan one year can be made for coal-fired power enterprise and cement enterprise. Cement enterprise can yearly save clay 76 600 t, cement mixture 86 200t. Energy consumption would yearly save 20 240t coal equi valent.更多还原