甘肃省低阶煤基活性炭的制备及性能研究

活性炭是一种经特殊处理的炭。煤基活性炭是一种以煤炭为原料,经过磨粉、成型、炭化、活化等工序制成的活性炭。以甘肃省中部地区窑街煤电金河煤炭为原料,在对原料煤进行工业分析、元素分析、二氧化碳反应活性测定的基础上,利用水蒸气活化法,通过单因素试验和正交试验设计,制备得到金河煤基活性炭,考察了活化时间、活化温度、水蒸气流量等因素对活性炭性能的影响。研究结果发现当活化温度为900℃,活化时间4h,水蒸气流量0.20mL/min时,金河煤基活性炭的最高碘吸附值为588mg/g,经酸法脱灰后,其吸附值增加至716mg/g。同时,将脱灰后的活性炭对初始浓度400mg/L苯酚废水进行处理,当投炭量0.10g、初始溶液pH值为7时,去除率可达79%。通过性能表征和吸附试验,验证了制备所得煤基活性炭具有良好的介孔结构和吸附性能。     

原料种类及热解温度对生物质炭理化特性影响的试验研究北大核心CSCD

为探究生物质原料和热解温度对生物质炭理化特性的影响,文章分别对松子壳、油茶壳、木屑和稻壳进行连续热解试验,获得生物质炭产物。通过对生物质炭的产率、工业分析与热值、吸附值、孔隙结构及表面官能团等理化特性的全面表征,研究原料种类及热解温度对生物质炭理化特性的影响。研究结果表明:松子壳炭、油茶壳炭、木屑炭的热值均大于标准热煤的热值;原料的挥发分含量越高,生物质炭的产率就越低,原料的灰分含量与生物质炭的灰分含量的变化趋势相一致;当热解温度为500℃时,4种生物质炭均可以形成较丰富的中、大孔隙结构,但松子壳、油茶壳等硬壳类生物质炭的微孔更为发达;随着热解温度的升高,生物质炭产率不断下降,生物质炭所含官能团的种类发生变化,数量逐渐减少,孔隙数量也减少,生物质炭的吸附能力减弱。     

活化和热解气氛对半焦基活性炭性能的影响

以煤炭分级转化半焦为原料，采用廉价烟气活化法制备适用于小分子污染物吸附脱除的活性炭，分别从活化工况、活化气氛、热解气氛三方面探究并对比了其物化性质和吸附性能。结果表明：分级转化半焦经烟气活化，在最优工况下可以得到比表面积为798.27 m²/g的活性炭，其微孔体积为0.327 cm³/g，碘值可达1056.84 mg/g。当固定烟气气氛中两种组分的浓度时，活性炭的碘值、比表面积和微孔结构随第三种组分浓度的增加呈现先升后降趋势。对比氮气热解半焦和模拟煤炭分级转化多联产系统的煤气热解半焦所制的活性炭，煤气半焦活性炭比表面积、微孔体积和碘值均有所提高，同时可以显著降低能耗，最优活化时间降低50%，经济性较好。     

活化过程对呼图壁煤制备活性炭性能影响研究

以新疆呼图壁煤为原料制备活性炭,研究不同活化过程对活性炭性能的影响。根据煤样热重分析结果设计炭化过程,以制备优质炭化料,然后选择在不同活化过程下制得活性炭。试验结果表明,呼图壁煤制备的活性炭吸附性能及孔隙结构均较为优良,H₂O(g)活化温度的降低有利于制得吸附性能、孔容积与比表面积均较高的活性炭,而高温H₂O(g)活化可得到微孔孔径更为细小的活性炭。相比H₂O(g)活化,CO₂活化有利于制得综合性能更为优良的活性炭。KNO₃催化活化可显著减少活化时间,但不利于制得孔隙结构发达的活性炭。     

煤质成分对煤基活性炭活化成孔的影响机制

以国内常用的8种煤为原料,在相同工艺下,采用KOH活化制备煤基活性炭.利用低温N2吸附、电子扫描电镜(SEM)等手段对活性炭表面的孔结构及表面形貌进行表征,考察原料煤的物理化学性质对煤基活性炭活化成孔的影响机制以及对表面孔隙结构的影响规律.结果表明,原料煤的原生孔隙、挥发分及固定碳有利于活性炭自身的微孔发展;而原料煤的含水量以及灰分含量和固定碳中不可活化的未分解碳氢物质会抑制活化成孔.最终制备出比表面积为546～978 m2/g、总孔容为0.32～0.57 cm3/g的活性炭。     

高中孔率木质素基活性炭的制备及表征

以秸秆木质素为原料,ZnCl_2为活化剂,将两者干法混合均匀后活化制备木质素基活性炭。通过单因素实验和Box-Behnken响应面实验得到高中孔率木质素基活性炭的最佳制备工艺条件为:盐料比1.5∶1,活化温度850℃,活化时间为60 min。该条件可使活性炭亚甲基蓝吸附值达到423.6 mg/g,比表面积达1224.38 m~2/g,平均孔径17.13 nm,总孔容2.165 cm~3/g,中孔孔容1.587 cm~3/g,中孔率达73.3%。     

微波裂解柚子皮制备活性炭的工艺研究

通过将柚子皮微波裂解制得柚子皮炭,用化学活化法制备高品质的柚子皮活性炭。活化剂选用H3PO4,ZnCl2,KOH和NaOH,并对每种活化剂的炭剂比、活化温度、活化时间和浸渍时间进行考察,以碘吸附值为主要品质衡量指标。试验结果表明,最佳工艺条件:活化剂为KOH,炭剂比为1∶2,活化温度为800℃,活化时间为1 h,浸渍时间为36 h。制得的柚子皮活性炭碘吸附值为1 318.21 mg/g,亚甲基蓝吸附值为225 mg/g,得率为42.17%,灰分为4.96%,吸附性达到木质味精精制用颗粒活性炭国家一级品标准。     

2021 年 1 期目录

以棉涤废料为炭前驱体,利用醋酸钙为模板剂,采用单因素法考察在不同热解温度、质量比和热解时间下制得的介孔炭对亚甲基蓝和四环素的吸附性能,从而筛选得到最佳制备工艺参数,同时利用氮气吸附?脱附曲线、扫描电镜、X射线衍射、红外光谱进行物化性能分析,并研究其对水中四环素的吸附规律。结果表明,制备棉涤废料基介孔炭的最佳工艺参数为：热解温度为800 ℃、醋酸钙和棉涤废料质量比为1.5∶1、热解时间为1.5 h。醋酸钙模板剂成孔性能优异,制得的介孔炭总比表面积高达1 106.630 m2·g?1,介孔率达到62%,对水中四环素的吸附过程符合Langmuir模型,为自发吸附,最大吸附值为506.40 mg·g?1。     

化学活化法制备柠条活性炭工艺研究

利用微波裂解技术处理柠条获得高品质的生物质油,大量剩余残炭可进一步活化成优质活性炭,从而推动生物质产业链并提高柠条的综合利用价值。以化学试剂辅以高温法生产活性炭,选取活化剂种类、柠条炭与化学试剂的炭剂比、活化温度、活化时间4个因素,以碘吸附值为主要指标,进行活化工艺优化。结果表明:H3PO4为活化剂的最优工艺条件为:炭剂比1∶1.5、活化温度550℃、活化时间80 min,该条件下活性炭水分、灰分、碘吸附值相应为9.80%、2.77%、1013.37 mg/g,3个主要指标均符合木质净水用活性炭的国家一级品标准。     

聚丙烯与梧桐锯末干混合制备成型活性炭研究

针对塑料及农林废弃物的处理,提出利用塑料及生物质干混合制备活性炭的方法,以达到以废治废的目的。以梧桐锯末为基体,聚丙烯塑料为填充剂,制作成型颗粒。采用K_2CO_3为活化剂,利用高温管式炉,研究城乡废弃物干混合制备成型活性炭工艺的可行性。通过4组独立的单因素实验阐析掺塑率、盐料比、活化温度以及活化时间对成型活性炭吸附性能的影响。研究表明:当掺塑率为5%、盐料比为2.0、活化温度为850℃、活化时间为60 min时,制备的成型活性炭具有较高的碘吸附值(1416.5 mg/g)。扫描电子显微镜(SEM)和Brunauer-Emmett-Teller比表面积测试法(BET)分析显示,成型活性炭具有发达的孔隙结构,比表面积为1738.7 m~2/g,总孔容为0.958 cm~3/g,平均孔径为3.1 nm。初步验证了此工艺的可行性。     

Ash-forming elements in four Scandinavian wood species. Part 1: Summer harvest

Woody biomass in Finland and Sweden comprises mainly four wood species: spruce, pine, birch and aspen. To study the ash, which may cause problems for the combustion device, one tree of each species were cut down and prepared for comparisons with fuel samples. Well-defined samples of wood, bark and foliage were analyzed on 11 ash-forming elements: Si, Al, Fe, Ca, Mg, Mn, Na, K, P, S and Cl. The ash content in the wood tissues (0.2–0.7%) was low compared to the ash content in the bark tissues (1.9–6.4%) and the foliage (2.4–7.7%). The woods’ content of ash-forming elements was consequently low; the highest contents were of Ca (410–1340 ppm) and K (200–1310), followed by Mg (70–290), Mn (15–240) and P (0–350). Present in the wood was also Si (50–190), S (50–200) and Cl (30–110). The bark tissues showed much higher element contents; Ca (4800–19,100 ppm) and K (1600–6400) were the dominating elements, followed by Mg (210–2400), P (210–1200), Mn (110–1100) and S (310–750), but the Cl contents (40–330) were only moderately higher in the bark than in the wood. The young foliage (shoots and deciduous leaves) had the highest K (7100–25,000 ppm), P (1600–5300) and S (1100–2600) contents of all tissues, while the shoots of spruce had the highest Cl contents (820–1360) and its needles the highest Si content (5000–11,300). This paper presented a new approach in fuel characterization: the method excludes the presence of impurities, and focus on different categories of plant tissues. This made it possible to discuss the contents of ash element in a wide spectrum of fuel-types, which are of large importance for the energy production in Finland and Sweden.     

NEXT GENERATION ENGINEERED MATERIALS FOR ULTRA SUPERCRITICAL STEAM TURBINES

正1 ABSTRACT To reduce the effect of global warming on our climate,the levels of CO2emissions should be reduced.One way to do this is to increase the efficiency of electricity production from fossil fuels.This will in turn reduce the amount of CO2emissions for a given power output.Using US practice for efficiency calculations,then a move from a typical US plant running at 37%efficiency to a 760℃/38.5 MPa(1 400/5 580 psi)plant running at 48%efficiency would reduce CO2emissions by 170kg/MW.hr or 25%.     

Aerodynamic performance effects of leading-edge geometry in gas-turbine blades

The purpose of this paper is to illustrate the advantages of the direct surface-curvature distribution blade-design method, originally proposed by Korakianitis, for the leading-edge design of turbine blades, and by extension for other types of airfoil shapes. The leading edge shape is critical in the blade design process, and it is quite difficult to completely control with inverse, semi-inverse or other direct-design methods. The blade-design method is briefly reviewed, and then the effort is concentrated on smoothly blending the leading edge shape (circle or ellipse, etc.) with the main part of the blade surface, in a manner that avoids leading-edge flow-disturbance and flow-separation regions. Specifically in the leading edge region we return to the second-order (parabolic) construction line coupled with a revised smoothing equation between the leading-edge shape and the main part of the blade. The Hodson–Dominy blade has been used as an example to show the ability of this blade-design method to remove leading-edge separation bubbles in gas turbine blades and other airfoil shapes that have very sharp changes in curvature near the leading edge. An additional gas turbine blade example has been used to illustrate the ability of this method to design leading edge shapes that avoid leading-edge separation bubbles at off-design conditions. This gas turbine blade example has inlet flow angle 0°, outlet flow angle −64.3°, and tangential lift coefficient 1.045, in a region of parameters where the leading edge shape is critical for the overall blade performance. Computed results at incidences of −10°,   −5°,   +5°,   +10° are used to illustrate the complete removal of leading edge flow-disturbance regions, thus minimizing the possibility of leading-edge separation bubbles, while concurrently minimizing the stagnation pressure drop from inlet to outlet. These results using two difficult example cases of leading edge geometries illustrate the superiority and utility of this blade-design method when compared with other direct or inverse blade-design methods.     

Hydrogen production by steam-gasification of carbonaceous materials using concentrated solar energy – V. Reactor modeling,optimization, and scale-up

A chemical reactor for the steam-gasification of carbonaceous particles (e.g. coal, coke) is considered for using concentrated solar radiation as the energy source of high-temperature process heat. A two-phase reactor model that couples radiative, convective, and conductive heat transfer to the chemical kinetics is applied to optimize the reactor geometrical configuration and operational parameters (feedstock's initial particle size, feeding rates, and solar power input) for maximum reaction extent and solar-to-chemical energy conversion efficiency of a 5 kW prototype reactor and its scale-up to 300 kW. For the 300 kW reactor, complete reaction extent is predicted for an initial feedstock particle size up to 35 μm at residence times of less than 10 s and peak temperatures of 1818 K, yielding high-quality syngas with a calorific content that has been solar-upgraded by 19% over that of the petcoke gasified.     

汽轮机数字电液调节系统挂闸异常的技术完善

分析了200MW汽轮机数字电液调节系统在运行中存在的挂闸异常问题,采取了相应的技术处理措施,且运行实践效果良好。     

新型高压共轨ECU升压模块的数字化开发与优化

为了提高喷油器电磁阀的响应速率,提出了一种基于CPLD(复杂可编程逻辑器件)应用于高压共轨ECU的数字升压模块。鉴于该升压电路结构参数多,其升压电压的恢复响应要求高等特征,基于Pspice建立了升压电路的仿真模型,研究了不同电路参数下升压模块的输出特性,全面优化了该升压模块的性能。结果显示,该升压模块的最大转换效率可以达90%以上。在柴油发动机上对ECU的试验表明,升压电压最大波动不超过10%,其恢复时间仅为1.3ms,功率管最大温升仅为41℃,满足整机运行范围内ECU的需求。     

Contents in Volume 23,2014

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Trace metal chemistry and silicification of microorganisms in geothermal sinter, Taupo Volcanic Zone, New Zealand

As part of a pilot study investigating the role of microorganisms in the immobilisation of As, Sb, B, Tl and Hg, the inorganic geochemistry of seven different active sinter deposits and their contact fluids were characterised. A comprehensive series of sequential extractions for a suite of trace elements was carried out on siliceous sinter and a mixed silica-carbonate sinter. The extractions showed whether metals were loosely exchangeable or bound to carbonate, oxide, organic or crystalline fractions. Hyperthermophilic microbial communities associated with sinters deposited from high temperature (92–94°C) fluids at a variety of geothermal sources were investigated using SEM. The rapidity and style of silicification of the hyperthermophiles can be correlated with the dissolved silica content of the fluid. Although high concentrations of Hg and Tl were found associated with the organic fraction of the sinters, there was no evidence to suggest that any of the heavy metals were associated preferentially with the hyperthermophiles at the high temperature (92–94°C) ends of the terrestrial thermal spring ecosystems studied.     

Assessment methods of material ageing using Sdobyrev''s creep rupture model

The physical aspects of the activation energy, in higher and high temperatures, of the metal creep process were examined. The research results of creep-rupture in a uniaxial stress state and the criterion of creep-rupture in biaxial stress states, at two temperatures, are then presented. For these studies creep-rupture, taking case iron as an example the energy and pseudoenergy activation was determined. For complex stress states the criterion of creep-rupture was taken to be Sdobyrev's, i.e. σ_red = σ₁ β + (1 − β)σ_i, where: σ₁-maximal principal stress, σ_i-stress intensity, β-material constant (at variable temperature β = β(T)). The methods of assessment of the material ageing grade are given in percentages of ageing of new material in the following mechanical properties: 1) creep strength in uniaxial stress state, 2) activation energy in uniaxial stress state, 3) criterion creep strength in complex stress states, 4) activation pseudoenergy in complex stress states. The methods 1) and 3) are the relatively simplest because they result from experimental investigations only at nominal temperature of the structure work, however, for methods 2) and 4) it is necessary to perform the experimental investigations at least at two temperatures.     

Production of hydrogen from sewage biosolids in a continuously fed bioreactor: Effect of hydraulic retention time and sparging

Hydrogen was produced from primary sewage biosolids via mesophilic anaerobic fermentation in a continuously fed bioreactor. Prior to fermentation the sewage biosolids were heated to 70 °C for 1 h to inactivate methanogens and during fermentation a cellulose degrading enzyme was added to improve substrate availability. Hydraulic retention times (HRT) of 18, 24, 36 and 48 h were evaluated for the duration of hydrogen production. Without sparging a hydraulic retention time of 24 h resulted in the longest period of hydrogen production (3 days), during which a hydrogen yield of 21.9 L H₂ kg⁻¹ VS added to the bioreactor was achieved. Methods of preventing the decline of hydrogen production during continuous fermentation were evaluated. Of the techniques evaluated using nitrogen gas to sparge the bioreactor contents proved to be more effective than flushing just the headspace of the bioreactor. Sparging at 0.06 L L min⁻¹ successfully prevented a decline in hydrogen production and resulted in a yield of 27.0  L H₂ kg⁻¹ VS added, over a period of greater than 12 days or 12 HRT. The use of sparging also delayed the build up of acetic acid in the bioreactor, suggesting that it serves to inhibit homoacetogenesis and thus maintain hydrogen production.