常压升温下油煤浆表观黏度变化的研究

为探讨煤直接液化工艺中油煤浆表观黏度随温度升高的变化规律,利用高温黏度计测定了煤浆体系的黏度,考察了溶剂、煤浆浓度、煤中含水量和不同显微组分等因素以及剪切速率、配浆温度、溶胀作用等对煤浆黏度 温度特性的影响。研究结果表明,低温下影响煤浆黏度变化的主要因素是溶剂本身的性质,煤浆的表观黏度随温度升高而降低;随温度继续升高在较宽温度范围内黏度变化不大,这是由溶剂性质以及煤在溶剂中的溶胀行为共同作用的结果;当温度达到约220℃后继续升高温度溶胀作用逐渐占优势,从而导致煤浆体系的表观黏度逐渐增大。     

胜利煤液化油煤浆表观黏度的影响因素研究

采用高温黏度计测定了胜利褐煤液化油煤浆在常压加热条件下的表观黏度,考察了煤浆质量分数、煤粉粒径、溶剂性质以及温度、剪切时间、剪切速率、溶胀等因素对煤浆体系表观黏度的影响。在常压室温至350℃的范围内,比较了胜利煤在起始溶剂和循环溶剂两种煤浆体系中的表观黏度。研究结果表明,胜利液化油煤浆体系是一种非牛顿流体,随着温度的升高,煤浆体系的黏度呈现先快速下降,然后基本保持不变,最后又逐渐上升的趋势。煤浆黏度保持不变的温度区间和黏度开始出现增加的温度随着煤浆的质量分数、煤粉的粒径以及配制煤浆所用溶剂的不同而不同。     

煤直接液化残渣的热解特性研究

利用热重、固定床热解和红外光谱技术研究煤直接液化残渣的热解特性及热解产物分布、组成和性质,考察了热解回收油品的适用条件。结果表明,450℃~500℃下神华煤液化残渣(SHR)和胜利煤液化残渣(SLR)热解油产率分别约为32%和20%,450℃后升高温度对油产率影响不大,但会使热解油中沥青烯(A)含量增加。SHR的热解油主要是己烷可溶物组分(HS),与SHR中HS结构相似。但SLR的热解油中A组分含量接近50%。SHR中的HS组分在热解时的聚合并不明显;而SLR中的HS组分在热解过程中伴随明显的聚合,导致热解油中含有大量的沥青烯。在400℃~500℃,两种残渣中A均有向热解油转化的趋势,而且SLR中A组分表现出了较大的逸出能力。但从热解产物组成分布分析,A的逸出还是少量的,一部分分解产生油品,一部分与前沥青烯和四氢呋喃不溶物(THFIS)一起形成了半焦。     

煤的缔合结构研究Ⅱ溶液黏度变化

采用Pal-Rhodes方程描述了一种煤可溶组分PI-1溶液黏度随时间的变化关系,并计算得到了缔合物的缔合维数。25 ℃下PI-1在NMP和CS2/NMP混合溶剂中缔合物的缔合维数分别为2.08和2.19,表明其在低温下缔合属于反应控制机理。随着温度的提高,缔合维数趋于减小,表明在较高温度下,PI-1具有较快的缔合动力学过程,在50 ℃时PI-1在NMP中的缔合维数大于在CS2/NMP混合溶剂中的缔合维数,表明PI-1在NMP的缔合速率相对低于CS2/NMP混合溶剂。     

煤直接液化残渣制备水渣浆成浆性的研究

以煤直接液化残渣制备了水渣浆,考察了粒径分布、搅拌时间、分散剂的用量及种类对水渣浆性质的影响。根据实验确定了制备水渣浆的最佳工艺参数：Alfred粒径分布模型（d_280~154μm、d_154~74μm、d_<74μm 质量分数分别为14%、16%、70%）,搅拌时间20 min,分散剂加入量为干渣基1.0%。实验结果表明,液化残渣制备水渣浆的定黏质量分数分别为73.5%（NSF）和71.0%（SL）。分散剂萘磺酸盐甲醛缩合物（NSF）的分散降黏效果优于改性碱木质素磺酸钠（SL）,而水渣浆的流变性,分散剂SL要优于分散剂NSF。     

煤与生物油的成浆性能研究

利用不同煤种的煤和生物油制备了不同浓度的生物油煤浆,考察了生物油煤浆的成浆浓度、表观黏度、流变特性和稳定性。结果表明,生物油煤浆是具有一定屈服应力的非牛顿流体,其流变特性可用宾汉姆方程来描述;生物油煤浆的屈服应力和表观黏度都随着固体浓度的增加而增大;随着剪切速率的增加,生物油煤浆的表观黏度减小;四种煤中,无烟煤的成浆浓度最高,可达42%,其含碳量高达49%,相当于同种煤制成的74%的水煤浆含量。烟煤次之,褐煤最低;生物油与煤粉之间能够形成絮凝性的大分子网络结构,使得生物油煤浆存在屈服应力并能够保持良好的静态稳定性,4.0~5.0 d天没有软沉淀产生,数月没有硬沉淀产生。     

褐煤中水分对油煤浆流变性质的影响

针对云南褐煤,用真空干燥脱水和恒温恒湿箱处理获得了不同含水率的褐煤,在常温常压(t=19.3℃,p=1.01×105Pa)条件下研究了褐煤含水率对油煤浆流变特性的影响。研究表明,原料煤含水率对油煤浆黏度和流变特性有一定的影响。随褐煤含水率增加,油煤浆黏度先减小后增加。油煤浆浓度不同,剪切速率不同,黏度出现最低值的含水率值wmin也不同。浓度为45.45%的油煤浆,剪切速率小于4.4 s-1时,wmin为9.20%;剪切速率大于4.4 s-1时,wmin为7.80%。浓度为55.56%的油煤浆,剪切速率小于1.32 s-1时,wmin为7.40%;剪切速率大于1.32 s-1时,wmin为10.00%。随剪切速率变化,油煤浆黏度上下行曲线之间形成滞后环,表明油煤浆体系有触变性,并且不同含水率煤浆体系触变性不同,含水率越大,触变性越明显。实验中不同含水率褐煤油煤浆都属于假塑性流体,且含水率对模型参数有一定的影响。     

煤浆浓度和颗粒分布对煤浆黏度预测的影响

采用神华煤制备煤浆,分析了颗粒粒径比λ和小颗粒体积分数ξ对双峰分布浆体黏度的影响,根据浆体黏度的关联式预测了煤浆的黏度并且与实验结果进行了比较。结果表明,采用双峰分布的颗粒制浆可以有效地降低浆体的黏度,同时可以获得较大的浆体体积分数 。在相同体积分数下,随着颗粒粒径比λ的增加,浆体的黏度迅速下降。当小颗粒体积分数ξ_dp1为35%时,浆体的黏度最小。采用Ouchiyama模型计算浆体的最大体积分数Φ_m与实验值较为吻合,而浆体的本质黏度[μ]基本保持不变。考虑λ和小颗粒体积分数ξ对双峰分布浆体的最大体积分数Φ_m的影响,可以采用单峰分布浆体的黏度关联式预测双峰分布浆体的黏度。     

煤直接液化残渣焦CO2气化反应的研究

比较了流化床条件下神华煤及其直接液化残渣焦在CO2气氛中的气化反应性,考察了添加液化催化剂、脱除矿物质以及脱除重质油对煤直接液化残渣气化反应的影响规律。结果表明,残渣焦的气化反应性比原煤焦好,残渣焦在1000℃和1100℃的气化反应性指数为0.135和0.290,而原煤焦的则为0.118和0.200。脱灰后残渣焦气化反应性低于脱灰后的煤焦,说明直接液化反应后剩余的难液化物质的气化反应性低于煤焦;未经脱灰处理的残渣焦气化反应性高于煤焦,反映了液化过程中富集的矿物质及铁系催化剂的催化气化活性。脱除残渣中的重质油会降低残渣焦的气化反应性。     

煤的润湿性及吸附性对煤成浆性的影响

本文讨论大同煤的润湿性、吸附性与煤成浆性的关系。不同类型的添加剂改善煤润湿性的能力不同,只有适当增加煤的润湿性才能配制成性能良好的煤浆。添加剂的合理用量可根据煤表面对添加剂的平衡吸附量来确定,此平衡吸附量用紫外分光光度计测定。实验表明,可用煤的润湿性、吸附性数值初步筛选煤浆的有效添加剂并确定其用量。     

山西典型高铝煤灰熔融及黏温特性改性实验研究

以山西典型高铝煤为研究对象,研究了工业助熔剂石灰石、黏土以及两者的复合助熔剂对其灰熔融特性及黏温特性的影响。结果表明,随着助熔剂含量的增加,煤灰熔融流动温度下降;石灰石的助熔效果优于黏土,复合助熔剂效果优于单一助熔剂。添加石灰石使灰渣临界黏度温度tcv显著降低,添加黏土使其渣型向玻璃渣转变,复合助熔剂较单一助熔剂存在显著协同作用,即能同时实现tcv的降低和渣型的有利转变。对山西典型高铝煤两渡煤,在复合助熔剂添加量为4%(2%石灰石+2%黏土)时,不仅其渣型向玻璃渣转变,且tcv较单独添加石灰石(2%)降低133℃,较单独添加黏土(6%)降低222℃。矿物质分析结果证实了助熔剂的助熔原理。添加复合助熔剂改性的山西高铝煤可达到工业气流床气化对煤种的要求。     

A new and reliable model for predicting methane viscosity at high pressures and high temperatures

In recent years, there has been an increase of interest in the flow of gases at relatively high pressures and high temperatures. Hydrodynamic calculation of the energy losses in the flow of gases in conduits, as well as through the porous media constituting natural petroleum reservoirs, requires knowledge of the viscosity of the fluid at the pressure and temperature involved. Although there are numerous publications concerning the viscosity of methane at atmospheric pressure, there appears to be little information available relating to the effect of pressure and temperature upon the viscosity. A survey of the literature reveals that the disagreements between published data on the viscosity of methane are common and that most investigations have been conducted over restricted temperature and pressure ranges. Experimental viscosity data for methane are presented for temperatures from 320 to 400 K and pressures from 3000 to 140000 kPa by using falling body viscometer. A summary is given to evaluate the available data for methane, and a comparison is presented for that data common to the experimental range reported in this paper. A new and reliable correlation for methane gas viscosity is presented. Predicted values are given for temperatures up to 400 K and pressures up to 140000 kPa with Average Absolute Percent Relative Error (EABS) of 0.794.     

Study of a thermotropic liquid-crystalline polyester at elevated pressures

A thermotropic liquid-crystalline copolyester of 20% hydroxybenzoic acid, 40% isophthalic acid, and 40% hydroquinone polymer was studied at elevated pressures. The characterization techniques at elevated pressures (0–1000 bar) included high-pressure differential thermal analysis and dilatometry; at atmospheric pressure, differential scanning calorimetry, thermal optical analysis, and x-ray analysis were employed. The mechanical properties of the solid specimens prepared at different pressures were studied by compression and dynamic rotation mechanical testing techniques. High-pressure induced a new crystal habit in the solid state and a new mesophase in the melt. These transitions are summarized in a proposed phase diagram. Mechanical tests on the material produced at elevated pressure indicate the possibility of improved properties, implying that the pressure-dependent morphological changes in thermotropic copolyesters could be of practical significance. The finding of a pressure-induced mesophase also confirmed the possibility of extending the range of polymers which might exhibit liquid crystallinity via the application of pressure.     

煤高温快速热解规律研究

利用高温滴管炉在1000℃～1400℃考察了彬县烟煤在高温快速热解过程中失重的变化,同时比较了埃塞俄比亚褐煤和晋城无烟煤的热解规律。结果表明,热解失重率随温度的升高而增加,而且各种煤种的最大失重率在高温下大于工业分析的失重率。对于不同变质程度的煤种其热解特性也不相同,较低的热解温度对高阶煤的影响较小。彬县原煤经过热解后比表面积增加,且随着热解温度的提高而增大,当热解温度超过灰熔点时,总比表面积降低。通过数据回归,得到了三种煤的失重率和热解温度的关联式。     

An apparatus for accurately measuring solubilities of gases in liquids at elevated temperatures and pressures

An apparatus for measuring solubilities of gases in liquids at elevated temperatures and pressures has been constructed. Using this apparatus, the solubilities of N₂ and CO₂ in some solvents have been determined in the temperature range between 20 and 230°C, and at pressures up to 130 atm. The experimental results obtained generally agree well with literature values. It is shown that this apparatus is reliable; attainment of equilibria needs only about 5 hours; precision of the measurements is ±0.2° o.     

Pressure and temperature dependences in p-ZnAs2 at high pressures

Kinetic effects in p-ZnAs₂ were measured at hydrostatic (P ≤ 9 GPa) and quasi-hydrostatic (to P ≤ 50 GPa) pressures on pressure buildup and depressurization. A conclusion on the occurrence of two phase transitions was made: I–II at P = 9–15 GPa and II-III at P = 30–35 GPa. Based on the temperature dependences of electrical resistance, it was shown that the conductivity is determined by activation mechanisms in a temperature range of 250–400 K; in this case, the activation energy changed with temperature and pressure. The pressure dependences of the activation energy and the coefficient R ₀, which characterizes the mobility, concentration, and effective mass of carriers, were calculated.     

Crystallization of polyethylene at elevated pressures

The crystallization from the melt of three sharp polyethylene fractions has been studied at 5 kbar. It has been shown that the thickness of so-called extended-chain lamellae is a function of time, temperature, and molecular weight. There is by no means just the fully extended molecular configuration present. Crystallization is qualitatively similar to that of chain-folded crystals at 1 bar, giving an optimum lamellar thickness which increases with time and decreasing supercooling. Fractional crystallization is widespread and is a major cause of disparate lamellar thickness. Isothermal thickening of lamellae during crystallization has been established directly. Morphological detail suggests further that layers can increase their thickness tenfold over their initial size.     

油浆高温快速裂解过程的气固相产物研究

采用高频炉快速热解装置研究油浆的高温快速热解特性,考察了热解温度、氮气流量对气固相产物的组成和产率的影响。温度是影响气相产物产率的关键因素,气相产物主要为甲烷、氢气和乙烯,升高温度可提高甲烷和氢气的产率,而乙烯产率受高温下二次反应的影响在800℃到达最大值后逐渐降低,乙烷、丙烯产率较小且受二次反应的影响在700℃到达最大值后逐渐降低,温度高于800℃时会有少量乙炔生成且升温可提高乙炔产率。增加氮气流量可降低甲烷、氢气分压,缩短乙烯、丙烯等在高温区的停留时间,从而增加气相产物的产率。积炭产率随热解温度升高迅速增加,氮气流量的增加能够削弱二次反应从而降低积炭产率。     

煤高温快速液化影响因素的研究

用17mL微型盐浴共振搅拌反应釜研究了煤高温快速液化。结果表明,煤阶低且含矿物质少的烟煤液化性能较好;转化率主要受溶剂供氢性能的影响;氢气所做贡献很小,与氮气气氛下的转化率基本一样;催化剂作用不明显;煤的粒径对转化率影响不大,反应器振动影响较大。综合结论分析其机理为,在煤的一次热分解温度范围的高温段,一般在500℃附近,低变质程度烟煤结构中的桥键可充分断裂,形成大量自由基,用足量优秀供氢溶剂作氢源,可有效稳定自由基,形成液体产物,在几十秒钟到几分钟的时间内就达到很高的转化率。