汽车同步器烧环成因及应对策略

本文简要说明了同步器的工作原理并给出了烧环三要素。对应烧环三要素,从驾驶、装配、制造和产品自身结构四个方面解析了同步器齿环烧环原因。针对四种原因中最棘手的一种——产品自身结构原因,围绕一个单锥改双锥的同步器设计实例可能引发的潜在换档问题(烧环)展开具体理论分析预判和试生产验证,并最终给出切实可行的烧环应对策略。

φ3880 mm多喷嘴水煤浆气化炉烧嘴压差优化总结

河南心连心化学工业集团股份有限公司二期气化装置3台φ3 880 mm多喷嘴水煤浆气化炉(D炉、E炉、F炉)两开一备,近年来烧嘴压差波动成为制约气化炉长周期运行的主要因素(运行周期平均仅43 d)。经分析与探讨,确定了优化改造原则与具体改造方案及步骤。改造试验实施后的试运行情况表明:第一阶段烧嘴室直径由360 mm缩小至325 mm,对烧嘴压差波动抑制效果明显,气化炉运行周期明显提升;第二阶段烧嘴环隙缩小后,并不能避免烧嘴压差波动;第三阶段烧嘴外环氧管包裹高温岩棉后,烧嘴压差整体稳定,烧嘴室积渣明显减少;第四阶段,烧嘴室直径由325 mm缩小至300 mm,气化炉运行周期明显延长(E炉运行周期达96 d)。总之,烧嘴室直径适度改小后,烧嘴压差波动情况得到缓解,大大延长了气化炉的运行周期。

谢尔气化共环式烧嘴损坏的原因分析及保护措施

烧嘴是渣油气化装置的关键设备,其作用是使渣油雾化,以及使油雾与气化剂(O2+H2O)充分接触,以实现气化反应。新型烧嘴有五个环隙,1、3环为 O2+H2O,2环为渣油,4环为屏蔽蒸汽,5环为冷却水(图1)。

试论环烧机的炉床粘结及清理

本文通过对莱芜市铁厂与马兰庄铁矿环烧机炉床粘结机理的分析,提出了解决此问题的新途径。

环烧机篦条的研制与生产

1.引言 环烧机篦条是环烧带中的主要易损件,由于工作条件比较苛刻,使用过程中的烧损、变形及断裂等比较严重,直接影响烧结矿的成本。五年来,多家生产厂为我们提供了不同材料的环烧机篦条,但效果都不太理想,篦条使用寿命一般为1～2个月。

环烧污水综合治理

1概述 环烧机是80年代末开发的一种适合中小型钢铁企业改造"平地吹"或"箱式鼓风吹"等土烧方法的新型烧结机.其特点是投资少、见效快、能耗少、产出多.

环氧氯丙烷交联聚乙烯醇膜的制备与性能

在碱性条件下用环氧氯丙烷(EPI)溶液对聚乙烯醇(PVA)膜进行交联改性,研究了EPI质量分数对PVA膜的耐水性、力学性能和表面亲水性的影响。研究结果表明:通过交联反应,提高了PVA膜的耐水性和力学性能,降低了其表面亲水性;随着EPI质量分数的增加,PVA膜的拉伸强度不断增强,当EPI质量分数为8%时,PVA膜的拉伸强度可达43.

超高碱值环烷酸镁研制

利用稠油环烷酸与氧化镁制备TBN4 0 0超高碱值环烷酸镁。通过对合成工艺条件的考察 ,确定一步法制备工艺。实验室小试及中型试验评价结果表明 :所制备产品的过滤性和稳定性良好 ,积炭疏松 ,胶体中的碳酸镁晶型为无定形。

Effect of sintering temperature on cycling performance and rate performance of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2

LiNi0.8Co0.1Mn0.1O2 powder was prepared by mixing LiOH·H2O and co-precipitated Ni0.8Co0.1Mn0.1（OH）2 at a molar ratio of 1：1.05, followed by sintering at different temperatures. The effects of temperature on the morphology, structure and electrochemical performance were extensively studied. SEM and XRD results demonstrate that the sintering temperature has large influence on the morphology and structure and suitable temperature is very important to obtain spherical materials and suppresses the ionic distribution. The charge-discharge tests show that the electrochemical performance of LiNi0.8Co0.1Mn0.1O2 powders becomes better with the increase of temperature from 700 ℃ to 750 ℃ and higher temperature will deteriorate the performance. Although both of materials obtained at 750 ℃ and 780 ℃ demonstrate almost identical cyclic stability at 2C rate, which delivers 71.9%retention after 200 cycles, the rate performance of powder calcined at 780 ℃ is much poorer than that at 750 ℃. The XRD results demonstrate that the poor performance is ascribed to more severe ionic distribution caused by higher temperature.

I MWth Test Facilities for Circulating Fluidized Bed Combustion

This paper presents the technical parameters and features of 1 MWth test facilities for circulating fluidized bed combustion (CFBC) at Thermal Power Research Institute (TPRI) of State Power Corporation (SP), introduces the test items that can be proceeded and trial combustion projects completed. The development status of CFBC technologies abroad and the level of China in this field are also introduced in the paper.

Calcium ferrite formation characteristic during iron ore sintering with different oxygen atmospheres

It is generally known that the large formation amount of calcium ferrite is favorable for the iron ore sintering. The effects of sintering temperature and O2 content of inlet gas on the calcium ferrite formation characteristic of typical iron ores, including hematite, limonite, specularite and magnetite, were investigated. And the effect of O2 content on the microstructure of the roasted briquettes was also studied in detail. The results show the amount of calcium ferrite initially increases then decreases with the increase of the sintering temperature. The temperature of maximum calcium ferrite generation amount is determined as follows： for hematite and limonite it is 1275 ~C, whereas for specularite and magnetite, 1250℃. The maximum contents of calcium ferrite for hematite, limonite, specularite and magnetite under the optimal sintering temperature are 73%, 82%, 67% and 63%, respectively. Increasing O2 content of the airflow is advantageous to the formation of calcium ferrite. Relatively, the effect of O2 content on the calcium ferrite formation of magnetite is the most pronounced, while O2 content of inlet gas has little effect on the calcium ferrite formation of limonite.

Combustion behavior and influence mechanism of CO on iron ore sintering with flue gas recirculation

The properties of circulating gas have a significant effect on sintering with flue gas recirculation,and the influence of CO in sintering process was investigated.The results show that the post-combustion of CO conducts in sinter zone when flue gas passes through the sintering bed,which releases much heat and reduces the consumption of solid fuel.The ratio of coke breeze can be reduced from 5% to 4.7% with 2% CO in circulating flue gas.In addition,with the increase of CO content in circulating flue gas,the combustion efficiency of fuel is improved,and the flame front is increased slightly while still matches with the heat transfer front.These are beneficial to increasing the maximum temperature and prolonging the high temperature duration,especially in the upper layer of sintering bed.As a consequence,the productivity,vertical sintering velocity and quality of sinter are improved.

Conversion of Fuel-N to N2O and NOx during Coal Combustion in Combustors of Different Scale

With focus on investigating the effect of combustor scale on the conversion of fuel-N to NOx and N20, experiments are carried out in three combustors, including single coal particle combustion test rig, laboratory scale circulating fluidized-bed boiler （CFB） and full scale CFB in this work. For single coal particle combustion, the majority of f-uel-N （65%-82%） is released as NOx, while only a little （less than 8%） fuel-N yields N20. But in labora- tory scale CFB, the conversion of fuel-N to N20 is increases, but the conversion of fuel-N to NOx is quite less than that of single coal particle combustion. This is because much char in CFB can promote the NOx reduction by in- creasing N20 formation. In full scale CFB, both of the conversion of fuel-N to NOx and the conversion of fuel-N to N20 are smaller than laboratory scale CFB.

ACCESSING HIGH THERMAL EFFICIENCY POWER GENERATION USING FLUID PHASE CHEMICAL LOOPING

In order to burn a hydrocarbon fuel efficiently using conventional cycles,very high temperatures are required.Chemical looping combustion（CLC）offers an alternative cycle for large scale power production.In CLC a carrier molecule is used to transport oxygen between two redox reactions,one where the carrier is oxidised and another where it is reduced by reaction with a fuel.Separation of the oxygen carrier from fuel ash can be aided by means of phase difference and this is a key advantage of fluid phase CLC where the carrier medium proposed is sodium,potassium or zinc.The principle exploited in fluid phase CLC is the recirculation of both energy and entropy.High thermal efficiencies,circa 75% at 35 bar are theoretically achievable taking into account component efficiencies,with separation of nitrogen and carbon dioxide,in combination with the water shift gas reaction,as an inherent part of the cycle if air is used as the oxygen source.

SYNTHESIS OF AG(NB_(0.8) TA_(0.2)) O_3 CERAMICS UNDER DIFFERENT AMBIENT CONDITIONS

Different ambient conditions for the synthesis of Ag（Nb0.8Ta0.2）O3 ceramics were investi- gated. The Ag（Nb0.8Ta0.2）O3 powder was synthesized at 950 ℃ under different ambient conditions, and then pressed into disks and sintered between 1060 ℃ and 1100 ℃ respectively. Samples were investigated by X-ray diffraction, scanning electron microscopy and dielectric measurement. The results show that perovskite Ag（Nb0.8Ta0.2）O3 powder was easier to be synthesized in air than in vacuum at 950℃. Grain size of ceramic samples sintered in air was uniform （about 1 μm） and its dielectric loss was small for its high density. However, the samples decomposed greatly and ceramics could hardly be densified when sintered in vacuum, Thus,. higher atmospheric pressure and oxygen atmosphere would benifit the synthesis of Ag （Nb0.8Ta0.2）O3, and suppress its decomposition at high temperature.

Preparation and Application of the Sol–Gel Combustion Synthesis-Made CaO/CaZrO_3 Sorbent for Cyclic CO_2 Capture Through the Severe Calcination Condition

Calcium looping method has been considered as one of the efficient options to capture C02 in the combustion Ilue gas. CaO-based sorbent is the basis for application of calcium looping and should be subjected to the severe calcination condition so as to obtain the concentrated C02 stream. In this research, CaO/CaZrO3 sorbents were synthesized using the sol-gel combustion synthesis （SGCS） method with urea as fuel. The cyclic reaction performance of the synthesized sorbents was evaluated on a lab-scaled reactor system through calcination at 950 ℃ in a pure C02 atmosphere and carbonation at 650 ℃ in the 15% （by volume） C02. The mass ratio of CaO to CaZr03 as 8：2 （designated as CasZr2） was screened as the best option among all the synthesized CaO sorbents for its high CO2 capture capacity and carbonation conversion at the initial cycle. And then a gradual decay in the C02 capture capacity was observed at the following 10 successive cycles, but hereafter stabilized throughout the later cycles. Furthermore, structural evolution of the carbonated CasZr2 over the looping cycles was investigated. With increasing looping cycles, the pore peak and mean grain size of the carbonated CasZr2 sorbent shifted to the bigger direction but both the surface area （SA） ratio and surface fractal dimension Ds decreased. Finally, morphological transformation of the carbonated CasZr2 was observed. Agglomeration and edge rounding of the newly formed CaC03 grains were found as aggravated at the cyclic carbonation stage. As a result, carbonation of CasZr2 with C02 was observed only confined to the external active CaO by the fast formation of the CaC03 shell outside, which occluded the further carbonation of the unreacted CaO inside. Therefore, enough attention should be paid to the carbonation stage and more effective activation measures should be explored to ensure the unreacted active CaO fully carbonatPd river the extended Ioonin cycles.

A novel suspension-floating-circulating fluidized combustion technology for coal slurry

A novel suspension-floating-circulating fluidized combustion technology is proposed for burning coal slurry fuel in traditional circulating ftuidized bed boilers （CFBB）. This technology can solve some existing problems in large- capacity CFBB burning coal slurry. The principles of the suspension-floating-circulating fluidized combustion technology were introduced in detail in this paper. A 130 t/h CFBB was retrofitted based on the technology, and the retrofitted system mainly includes a long-distance transport sub-system, a bed-material conveying sub-system with a wind-seal device invented by the authors, a superheater thermoregulation device using a novel temperature regulator, a return loop flu- idization facility, and a pneumatic ash conveying sub-system with sealed pump. The achieved performance of the retro- fitted CFBB shows that the thermal efficiency is 89.83 %, the combustion efficiency is 96.24 %, and the blending proportion of slurry is 94 %.

Unexpected Chemistry from the Homogeneous Thermal Decomposition of Acetylene:An ab initio Study

The formation of the aromatic ring during the formation of polycyclic aromatic hydrocarbons (PAHs) remains controversial and the experimental evidence is still lacking. Moreover, the formation mechanism of benzene from acetylene in the gas phase has also puzzled organic chemists for decades. Here, ab initio molecular dynamics simulations and electronic structure calculations provide compelling evidence for an unexpected competitive reaction pathway in which the aromatic ring is formed through successive additions of vinylidene. Moreover, no collisions cause bond dissociation of the acetylene molecule during the formation of benzene in this work. This study reveals the key role for the vinylidene carbene and determines the lifetime of vinylidene.

Investigation into Syngas Generation from Solid Fuel Using CaSO4-based Chemical Looping Gasification Process

Chemical-looping gasification （CLG） is a novel process for syngas generation from solid fuels, sharing the same basic principles as chemical-looping combustion （CLC）. It also uses oxygen carriers （mainly metal oxide and calcium sulfate） to transfer heat and oxygen to the fuel. In this paper, the primary investigation into the CLG process with CaSO4 as oxygen carrier was carried out by thermodynamic analysis and experiments in the tube reactor. Sulfur-contained gas emission was mainly H2S rather than SO2 in the CLG process, showing some different features from the CLC. The mass and heat balance of CLG processes were calculated thermodynamically to determinate the auto-thermal operating conditions with different CaSO4/C and steam/C molar ratios. It was found that the CaSO4/C molar ratio should be higher than 0.2 to reach auto-thermal balance. The effect of temperature on the reactions between oxygen carrier and coal was investigated based on Gibbs free energy minimum method and ex- perimental results. It indicated that high temperature favored the CLG process in the fuel reactor and part of syngas was consumed to compensate for auto-thermal system.