Direct reduction of carburized pre-reduced pellets by microwave heating

A new iron-making process using carburized pre-reduced iron ore pellets and microwave heating is investigated.The pre-reduced pellets,with a porous structure,and fine particles are carburized homogeneously at 400-650 °C in a CO atmosphere.The carburized carbon not only acts reaction as a reduction agent,but also absorbs microwave in the reduction process.Hence,the carburized pre-reduced pellets can be rapidly reduced by microwave heating.There are three procedures involved in the process,namely,gas-based pre-reduction,low-temperature carburization and deep reduction by microwave heating.Carburized pre-reduced iron ore pellets show a rapid temperature rise that is twice as fast as the results for pre-reduced pellets in the laboratory.This not only improves the efficiency of the microwave heating,but also accelerates the reduction of iron oxides.The temperature of the pre-reduced pellets rises to 1050 °C in 45 min when the carburization rate is 2.02%,and the metallization rate and compressive strength reach 94.24% and 1725 N/pellet,respectively.

Calcium looping heat storage performance and mechanical property of CaO-based pellets under fluidization

The CaO-based pellets were fabricated using extrusion-spheronization method for calcium looping thermochemical heat storage under the fluidization.The effects of adhesive,biomass-based pore-forming agent,binder and particle size on the heat storage performance and mechanical property of the CaObased pellets were investigated in a bubbling fluidized bed reactor.The addition of 2%(mass)polyvinylpyrrolidone as an adhesive not only helps granulate,but also improves the heat storage capacity of the pellets.All biomass-templated CaO-based pellets display higher heat storage capacity than biomass-free pellets,indicating that the biomass-based pore-forming agent is beneficial for heat storage under the fluidization.Especially,bagasse-templated pellets show the highest heat storage conversion of 0.61 after 10 cycles.Moreover,Al_(2)O_(3)as a binder for the pellets helps obtain high mechanical strength.The CaO-based pellets doped with 10%(mass)bagasse and 5%(mass)Al_(2)O_(3)reach the highest heat storage density of 1621 kJ·kg^(-1) after 30 cycles and the highest crushing strength of 4.98 N.The microstructure of the bagasse-templated pellets appears more porous than that of biomass-free pellets.The bagassetemplated CaO-based pellets doped with Al_(2)O_(3)seem promising for thermochemical heat storage under the fluidization,owing to the enhanced heat storage capacity,excellent mechanical strength,and simplicity of the synthesis procedure.

饲料颗粒压缩成型力学行为表征研究

为了解不同湿热处理条件对饲料制粒过程力学行为的影响,利用自主搭建的单颗粒压缩(single pellet press,SPP)试验平台,完成了15%、20%和25%水分饲料在70、80、90℃下经过1、3、5 min热处理的颗粒压缩成型试验。根据应力变化率将饲料的压缩曲线划分为压杆入模、挤压段、屈服段和压紧段4个阶段;采用应变强化非线性弹性元件和牛顿黏滞体并联的方式建立了表征压紧段力学行为的非线性弹塑黏性流变模型,模型的决定系数R2>0.98,平均相对百分误差(e)范围为0.52%~7.13%。湿热处理条件对压紧段流变模型参数的影响分析表明:随着饲料水分和热处理温度的升高,饲料压缩变形中塑性变形所占比例增大;而随着热处理时间的延长,弹性变形比例增大。饲料水分的提高有利于湿热处理后饲料中淀粉、蛋白质等黏结剂成分的表达,高水分饲料的压缩特性对温度的敏感性下降。

张宣科技氢基竖炉开炉操作

对张宣科技氢基竖炉开炉操作实践进行了总结。氢基竖炉采用焦炉煤气COG作为气源,开炉前,重点保证高品质球团矿稳定供应、系统分级试压检漏消除漏点、建立塔器液位及循环;2023年5月10日点火开炉,开炉过程中,主要做好启动COG压缩机、加热炉点火升温、装排料、引送高压COG、并入CO_(2)脱除系统、启用喷氧系统等工作,并进行加风强化和控制DRI化学成分操作。5月20-21日,DRI含C量下降至3%左右,达到炼钢电炉的配加要求,且DRI金属化率提升至94%以上,达到设计水平。

清洁环保型熔盐炉及烟气余热回收节能装置研究

分析了燃天然气立式圆筒型熔盐炉的结构型式,研究了燃生物质柴油立式圆筒型熔盐炉的构造(组成),讨论了燃生物质固硫型煤熔盐炉的机械化燃烧装置与立式圆形盘管式炉体结构特点,探讨了熔盐炉烟气余热回收利用节能装置的常用结构型式:对流型换热器、辐射型换热器、热管式换热器、余热锅炉。

唐钢高炉炼铁技术进步

河钢集团唐钢新区是以工艺现代化、设备大型化、物流运输智能化、资源能源循环化、生产绿色化为基础,打造的绿色化、智能化、品牌化新型沿海钢铁基地。三座高炉自投产以来,上部装料坚持“稳定边缘、打开中心,稳定中心、兼顾边缘”的煤气流控制方针;下部采用高风速、高动能的送风制度;坚持低硅冶炼,合理控制铁中[Si+Ti]含量≯0.45%;优化造渣制度,控制渣中MgO/Al_(2)O_(3)在0.55;构建基于“三位一体”精益运营管理模式的高炉长周期稳定顺行管理体制,形成了一套适应高比例球团矿冶炼的高炉炼铁技术,在入炉球团矿配比42%的前提下,高炉最高日产量突破9000 t/d,煤比最高168 kg/t,燃料比最低498 kg/t,各项技术指标均创投产以来新高。

Conceptual Design of 25-Barrel Pellet Injector with Cycle Refrigerator for HL-2A Tokamak

The preliminary design of a multi-barrels pellet injector with cycle refrigerator as an advanced plasma-fuelling tool for HL-2A tokamak has been proposed. The design aims at precise temperature control, easy operation with high reliability and high flexibility. GM-cycle refrigerator and pipe-gun structure have been employed to produce 25 pellets in 25 gun barrels simultaneously and the design aims. have been accomplished. Prime design principle, engineering parameters, structure and layout of the cryostat components as well as calculation of heat load for the cryostat are presented.

甘露消毒丹联合退黄汤治疗慢加急性肝衰竭湿热蕴结证患者的临床观察

目的探讨甘露消毒丹联合退黄汤治疗慢加急性肝衰竭湿热蕴结证患者的临床疗效。方法选择安徽中医药大学第一附属医院就诊的慢加急性肝衰竭患者74例,根据随机数字表法分为对照组与观察组,各37例,两组均给予西药常规治疗,对照组患者给予退黄汤灌肠治疗,观察组在对照组基础上给予甘露消毒丹口服治疗,水煎服400 mL,日1剂,分早晚2次,饭后温服各200 mL,连续治疗8周。观察两组治疗前后临床疗效;进行中医证候评分;检测丙氨酸氨基转移酶(alanine aminotransferase,ALT)、天冬氨酸氨基转移酶(aspartate aminotransferase,AST)、白蛋白(albumin,ALB)以及总胆红素(total bilirubin,TBIL)评价肝功能;检测凝血酶原时间(prothrombin time,PT)、凝血酶原活动度(prothrombin time activity,PTA)评价凝血功能;腹部彩超检查肝右叶厚度、门静脉内径和胆囊壁厚度。结果治疗后观察组总有效率91.89%,显著高于对照组的70.27%(P<0.05)。治疗后两组中医证候评分均较治疗前降低,且观察组低于对照组(P<0.05)。治疗后两组ALT、AST、TBIL指标均较治疗前降低,ALB较治疗前升高,且观察组优于对照组(P<0.05)。治疗后两组PT指标均较治疗前降低,两组PTA指标均较治疗前升高,且观察组优于对照组(P<0.05)。治疗后两组门静脉内径、胆囊壁厚度均较治疗前降低,肝右叶厚度较治疗前升高,且观察组优于对照组(P<0.05)。结论甘露消毒丹联合退黄汤治疗慢加急性肝衰竭患者具有一定临床疗效。

转底炉金属化球团滚筒冷却机传热模型研究

针对目前冶金行业转底炉工艺中圆筒冷却机无法回收球团显热的问题,本文提出采用在循环流化床锅炉中广泛应用的滚筒冷却机来冷却球团的新方案,并据此建立滚筒冷却机的传热模型,通过计算得到球团终温与冷却水出口温度及冷却机的表观传热系数。结果表明:球团的终温随滚筒转速的升高而降低,随球团流量和冷却水入口温度的升高而升高;冷却水出口温度随金属化球团流量和冷却水入口温度的增大而增大;冷却机的表观传热系数随滚筒转速、球团流量和冷却水入口温度的增大而增大,随冷却水流量的增大而减小。本文引入滚筒冷却机将球团的温度从1100℃降低至70℃,同时避免球团内部的氧化问题,符合高温球团的冷却要求,证明了将滚筒冷却机用于转底炉工艺的可行性。

解毒生化丹方联合奥沙利铂干预湿热瘀毒型结直肠癌临床疗效

目的探究解毒生化丹方联合奥沙利铂干预“湿热瘀毒”型结直肠癌的临床疗效。方法选取医院2021年1月—2022年1月收治的107例结直肠癌患者为研究对象,采用随机分组法分为观察组54例与对照组53例,对照组使用FOLFOX方案(奥沙利铂+氟尿嘧啶+醛氢叶酸)治疗,观察组采用FOLFOX方案一半的剂量联合使用解毒化生丹治疗。观察两组患者治疗前后肿瘤因子标志物水平、血清癌基因ras。观察两组患者临床疗效、生活质量评分、不良反应发生率。结果两组患者治疗前CA199、CEA、CA242水平差异无统计学意义(P>0.05)。治疗后观察组CA199、CEA、CA242水平显著低于对照组(P<0.05)。两组患者治疗前COX-2、rasP21水平差异无统计学意义(P>0.05)。治疗后观察组COX-2、rasP21较对照组显著降低(P<0.05)。两组患者治疗前生理功能、身体疼痛、角色限制、总体健康、社会功能、活力、精神健康、情感职能评分差异无统计学意义(P>0.05)。治疗后观察组生理功能、身体疼痛、角色限制、总体健康、社会功能、活力、精神健康、情感职能评分显著高于对照组(P<0.05)。两组患者治疗后观察组客观有效率为27.75%显著高于对照组11.28%(χ^(2)=4.592,P=0.032)。观察组疾病控制率为66.60%略高于对照组48.88%,但两组患者疾病控制率无显著性差异(χ^(2)=3.403,P=0.065)。两组患者治疗后观察组总不良发应为7.40%略低于对照组7.52%,但两组患者总不良发应率无显著性差异(χ^(2)=0.001,P=0.978)。结论解毒生化丹方联合奥沙利铂能有效降低患者毒副反应、提升患者临床疗效、降低肿瘤因子和血清癌基因ras、改善患者生活质量水平。

Field assessment of straw pellet combustion in improved heating stoves in rural Northeast China

Straw pellets are widely promoted and expected to be a cleaner alternative fuel to unprocessed crop residues and rawcoal in rural China.However,the effectiveness of these dissemination programs is not well evaluated.In this field study,emission characteristics of burning strawpellets,rawcoal,and unprocessed corn cobs in heating stoveswere investigated in a pilot village in Northeast China.Emission measurements covering the whole combustion cycle(ignition,flaming,and smoldering phases)shows the promotion of improved heating stoves and straw pellets could reduce pollutant emissions(e.g.,SO_(2) and CO),but increase NO_(X) and PM_(2.5) emissions compared to the initial stove-fuel use pattern in the studied area.There is a significant variance in emission characteristics between different combustion phases.The normalized emission concentrations of the different stove-fuel combinations were higher than the limits in the Chinese national standard for heating stoves,indicating that the standard is not met for real-world emissions.Coal consumption was lower than official data.Household surveys were conducted to identify the barriers to fuel and stove access associated with existing promotion strategies,management,and policies.The pilot program was of the typical“subsidy-and-policy-dependence”pattern and was unlikely to be implemented on a large scale.Technological innovation,operational optimization,and proper policies considering the local socioeconomic factors are needed to sustain the promotion of biomass straw pellets and stoves.

Gas release characteristics during carbonization of iron coke hot briquette and influence of heating rate

The release characteristics of CH_(4),H_(2),CO and CO_(2) from iron coke hot briquette(ICHB)during carbonization were studied.The results show that compared with briquette without iron ore,Fe_(3)O_(4) can inhibit the release rate of H2 and promote the production of CO and CO_(2).In addition,when the heating rate increases from 3 to 7℃/min,the release rates of CH4 and H2 increase,while the release rates of CO and CO_(2) first increase and then decrease.The carbonization process of ICHB was segmented,and corresponding kinetic analysis was carried out.The results show that the activation energy of StageⅡand StageⅣis higher in the carbonization process of ICHB,and the active pyrolysis of coal and the reduction of iron ore occur in these two stages.In addition,the effect of heating rate on the kinetic parameters of ICHB carbonization process was investigated.It was found that when the heating rate increased,the reaction activation energy of StageⅣdecreased first and then increased,which was consistent with the release law of CO and CO_(2).The analysis showed that the increase in heating rate leads to more reactions at higher temperatures,resulting in an increase in the release rate of some gases.In addition,thermal hysteresis can also cause some processes to fail to fully react at the end of heating.It is also found that the apparent activation energy and preexponential factor have kinetic compensation effect during the car-bonization of ICHB.

生物质成型燃料用于我国村镇供暖研究进展

中国北方冬季气候严寒,煤炭作为主要供暖燃料严重污染环境。双碳目标背景下,全面推进北方地区清洁取暖意义重大,合理利用零碳排放的生物质资源尤为重要。针对当前北方村镇生物质成型燃料供暖现状,结合相关供暖方案进行综述,明确了我国生物质成型燃料发展存在原料收集与供应、成型与燃烧设备的发展、相关政策与标准体系等方面问题。在优化炉具质量、提高劣质生物质原料利用率等方面提出建议;并基于此对我国各地生物质成型燃料供暖政策进行对比分析,发现生物质在新能源供暖中优先级较低;对生物质成型燃料村镇供暖成功案例进行分析,提出应因地制宜地选择供暖模式并形成完善的产业链体系;构建农户就地收集、企业就近加工、全域就地使用的方案,按照企业为主、政府推动、居民可承受的思路,探索生物质清洁供暖模式。

燃生物质固硫型煤有机热载体炉节能措施及自动控制

分析了燃生物质固硫型煤有机热载体炉的立式圆形盘管型、卧式管架型、卧式方箱盘管型的结构型式,讨论了有机热载体炉的节能减排措施,研究了空气型、热水型、蒸汽型的烟气余热回收装置的结构形式,探讨了有机热载体炉的自动控制及安全保护,包括检测显示、自动调节、操作控制、信号保护及联锁等。

预热竖窑气固传热与水分蒸发数值模拟

通过对一种新型预热竖窑的预热脱水研究,建立了气固两相传热和水分蒸发收缩核模型.在气体速度分别为10,15和20 m/s与993 K的温度条件下,针对预热竖窑的气体温度分布,以铬铁球团为主的固体混合物料温度分布和水分蒸发情况进行模拟分析.结果表明,该预热竖窑在20 m/s与993 K的条件下,固体物料温度达到850 K以上并实现球团干燥,可以满足物料预热的温度和含水量要求.通过合理的预热工序,防止了冶炼过程中因含水率过高导致球团出现爆裂影响生产安全的问题,也满足了企业对冶炼过程中产生的高温尾气的余热利用的目标.

Aspen EDR在炭黑造粒水换热器设计校核上的应用

炭黑是一种重要的橡胶补强剂,其广泛应用于汽车轮胎、非轮胎橡胶制品、塑料、涂料等行业。因炭黑生产过程中主要是以粉体形式输送,为降低炭黑粉尘对环境的影响,多数炭黑企业均采用湿法造粒工艺对粉状炭黑进行加工。造粒工艺是将粉状的炭黑送至炭黑造粒机中,同时向造粒机中喷入造粒水及其他添加剂,最终将粉状炭黑加工成颗粒状炭黑。由于造粒水的水温会对炭黑粒子大小和外观有一定的影响且工厂内现有的造粒水换热器换热效果不能满足工艺要求,故此次使用Aspen EDR软件完成换热器的设计与校核,不仅达到了工艺要求,而且计算过程简洁明了,大大提高了设计效率。

生物质户用供热技术发展现状及展望

介绍了国内外生物质户用供热产业、技术的发展现状,分析了国外应用比较广泛的生物质供热设备的特点以及生物质和太阳能联合供热系统,指出了生物质供热技术存在的主要问题,并提出我国生物质户用供热技术的发展方向,发展生物质户用供热技术将有效地缓解由农村传统供热带来的资源环境问题,具有良好的环境、经济和社会效益。

生物质固体成型燃料环模成型技术研究进展

综合分析了国内外生物质固体成型燃料环模成型技术、成型设备及产业发展现状,比较了生物质环模颗粒成型机和生物质环模压块成型机的性能和产品,指出了生物质固体成型燃料环模技术及设备存在着基础理论薄弱、原料适应差、易损件寿命短等问题;提出了我国生物质固体成型燃料环模成型技术的发展方向。

用粗糙集理论评价生物质固体成型燃料技术的研究

由于生物质固体成型燃料技术在中国处于发展初期,技术水平良莠不齐,对其进行综合评价比较复杂,且具有不确定性。该文基于粗糙集理论提出了一种综合评价模型,该模型将模糊综合评价中权重系数的确定转化为粗糙集理论中属性重要性的计算,有效地克服了现有评价模型中权重系数确定的主观性,从而使评价的结果更加客观。利用模型对生物质固体成型燃料技术进行了综合评价,得到了符合实际的评价结果,并结合设备使用要求和技术条件,确定了包括机械活塞成型、胶凝粘结成型、液压活塞成型、对辊挤压成型、环模压辊成型等在内的适宜优先推广的技术评价方案。