焦炉煤气自重整成分变化规律热力学计算

基于焦炉煤气的CH4-H2-H2O-CO-CO2-O2体系,通过热力学平衡模拟计算,对焦炉煤气自重整过程中成分变化规律的影响因素进行了研究与分析。研究结果表明:高温、高CH4含量及低体系压力有利于焦炉煤气自重整。在原始炉气成分中CH4的体积分数为26.4%,氧气加入量为13%,重整温度为900℃和系统压力为0.2MPa的情况下对焦炉煤气进行自重整,则还原气平衡态组分中H2的体积分数可由57.4%提高到约72.6%;CO的体积分数可由8.6%提高到约24.0%。     

气基竖炉工况焦炉煤气甲烷改质行为试验

 利用焦炉煤气+气基竖炉生产优质海绵铁,可延伸焦化行业产业链,同时可促进中国废钢/海绵铁—电炉短流程发展,改变钢铁行业能源、产品结构。针对典型焦炉煤气,通过基础性试验研究了在气基竖炉工况下,温度、H2O和CO2配比,高温海绵铁载体对焦炉煤气中甲烷改质行为的影响。研究结果表明,提高温度有利于焦炉煤气中甲烷的改质反应,1000℃时改质后有效还原气体体积分数最高可达80%;热态海绵铁对焦炉煤气改质有催化促进作用,可提高CO2参与改质反应比例至84.9%、H2O参与反应比例至100%;CO2配入体积分数2%～6%、H2O配入体积分数4%～10%为促进甲烷改质反应的适宜范围。     

焦炉煤气催化部分氧化转化的实验研究

用部分氧化转化法进行了焦炉煤气中甲烷的重整转化实验,分别考虑了（CO2＋H2O）／CH4比例、反应温度丁及配氧量三个因素对甲烷转化率的影响。研究结果表明：焦炉煤气中甲烷重整转化的最佳动力学条件是（CO2＋H2O）／CH4=1．1～1.3、反应温度T=1223-1323K、配氧量O2=6％左右,CH4的转化率大于95％。     

焦炉煤气重整成分变化规律热力学计算

为明确焦炉煤气重整工艺中温度及组分对焦炉煤气重整平衡组分的影响规律，对CH₄-H₂-CO-CO₂-H₂O-O₂竖炉焦炉煤气体系自重整过程中温度、压力、O₂、CO₂和H₂O的变化规律进行了热力学平衡模拟研究。结果表明：高温以及较低的体系压力对焦炉煤气自重整有利，但CH₄转化率较低。在给定焦炉煤气成分及条件下，焦炉煤气重整过程中加入O₂会使CH₄转化变得容易，计算得到的O₂最佳加入量为5.69%(摩尔分数),此时CH₄转化率已经达到99.48%,还原气平衡组分中H₂的摩尔分数可由68.39%提升至75.99%,CO摩尔分数由4.36%提升至18.12%,H₂与CO体积比降至4.19;CO₂加入量是调节焦炉煤气平衡组分中H₂...     

焦炉煤气竖炉法生产DRI的煤气用量及利用率

根据中国资源特点及国内焦炉煤气利用不合理的现状,认为部分地区发展中小型焦炉煤气-气基竖炉工艺生产高品质直接还原铁在技术上是可行的。将焦炉煤气应用于MIDREX竖炉工艺,基于理论计算,探讨焦炉煤气-MIDREX竖炉生产DRI的煤气用量以及煤气利用率,为中国气基竖炉工艺的发展提供工艺参数。结果表明,焦炉煤气经重整后所得还原气体的H_2和CO体积分数比值为2.18,每生产1tDRI需要消耗焦炉煤气599.70m3。当向竖炉通入1 800m~3/t的还原气体时,竖炉内H_2、CO的利用率分别为32.14%和36.14%,还原气综合利用率为33.61%。     

风量对烧结烟气成分影响的实验研究

通过对工业冶金烧结过程进行简化,建立了小型固定型的热态烧结试验台,考察了风量对烧结烟气中可燃稀薄气体组分（CO、H2和CH4）体积分数变化的影响。研究结果表明： CO和H2体积分数随风量与时间的变化趋势相似,呈现刚开始快速增加后平稳再急速下降的变化,CO与H2体积分数总体变化为随着风量的增大而减小;燃烧比φCO/（φCO+φCO2）在风量为100m3/(m2·min)左右时较低,说明此时碳的化学能利用较高,但考虑风量提高伴随风机电耗的提高和漏风量的增加,烧结风量为90m3/(m2·min)是实验中得出的较优风量;CH4体积分数在各个风量下都呈现先快速增加再平稳到接近烧结终点后体积分数剧烈减小,且在烧结风量为70m3/(m2·min)时最大,最高接近2%（体积分数）。此实验结果为烧结实际生产的风量选择和烟气回收等节能减排项目提供了一定的参考。     

富氢还原对烧结矿还原性及还原粉化的影响

钢铁工业CO2排放量约占全球总排放量的8%,为了降低CO2排放量,发展以H2为还原剂的炼铁生产方式势在必行。针对富氢还原对烧结矿还原性及还原粉化的影响进行了试验研究和理论分析。研究结果表明：H2等量代替CO时,H2体积分数由0%增加到12%,烧结矿的RDI-3.15降低约1%~2%;H2等量增加,CO,CO2,N2含量等比例降低时,H2体积分数由0%增加到12%,烧结矿的RDI-3.15升高约1.5%~2.5%;H2体积分数从0%增加到12%,烧结矿还原度Ri由72.56%增加到94.97%。研究结果对于开发富氢还原工艺具有重要的理论参考价值。     

低温非平衡条件下氧化铁还原顺序研究

研究了低温条件下(＜570℃)CO和H2还原氧化铁的动力学机理.结果表明:实际还原过程属于非平衡态过程,它的还原机理与还原气体的成分相关.当还原气体中CO(或H2)的含量不能满足Fe3O4 CO(H2)→3FeO CO2(H2O)反应进行的要求时,氧化铁的还原顺序为Fe2O3→Fe3O4→Fe;如果还原气体成分满足此要求,Fe2O3→Fe3O4→Fe和Fe2O3→Fe3O4→FeO→Fe两种还原顺序将同时存在.     

块状铁矿石竖炉磁化焙烧的工艺优化

竖炉磁化焙烧是处理难选红铁矿较有效的方法。通过对弱磁块矿竖炉磁化焙烧的试验研究,提出了更加科学、高效的竖炉磁化焙烧理论,在现有鞍山式竖炉的基础上,通过高效控制铁矿石竖炉磁化焙烧还原气氛,对竖炉磁化焙烧工艺进行了优化。结果表明：还原气体H2体积分数提高到12%±1%,同时降低CO体积分数,提高块矿焙烧还原温度,可获得最佳的磁化焙烧效果;通过独立设置铁矿石磁化焙烧还原煤气系统与加热煤气系统,可实现还原煤气的成分、流量、压力灵活调节;通过减少还原煤气总量,将矿石还原煤气量降低至1400～1600m3/h,降低竖炉的生产成本;通过独立的还原煤气系统,提高还原煤气中焦炉煤气比例,将H2体积分数控制在12%±1%,矿石磁化率控制在2.33左右,降低了竖炉磁化焙烧煤气消耗,提高矿石磁化焙烧质量;为保证还原煤气降低用量后的压力和喷出的均匀性,将还原煤气喷出塔的出口面积缩小50%,使矿石能够充分、均匀地完成还原。     

焦炭反应性对高炉块状带含铁炉料还原的影响

研究了五种具有不同反应性的焦炭对高炉块状带含铁炉料还原的影响规律,并对料层的压差、CO体积分数以及含铁炉料的还原程度进行了分析.当炉内通入的原始气体中CO体积分数(仅考虑CO和CO₂)为72.22%时,随着焦炭反应性的增强,焦炭气化速率加快,含铁炉料颗粒周围的CO体积分数升高,含铁炉料的还原度依次增高,还原度从使用低活性焦炭时的33.18%增大到使用高活性焦炭时的53.83%;而当原始气体成分中CO体积分数为66.67%时(低于900℃还原FeO的平衡气相体积分数),使用高反应性焦炭也可还原出金属铁.由此可见,适当增加入炉焦炭的反应性,可促进焦炭与含铁炉料间的耦合反应,提升料层CO体积分数,提高含铁炉料进入软熔带区域的金属化率.      

Effect of Water Vapor on O2- Content in Ironmaking Slag

In principle,slag basicity can be expressed as the concentration of free oxygen(O2-) in the slag system.This free oxygen content is equilibrated with different silicate anions in addition to other components in the silicate-based slags.X-ray photon spectroscopy(XPS) and scanning electron microscope equipped with energy dispersive spectrometer(SEM-EDS) were used to investigate the effect of water vapor on the free oxygen content in ironmaking slags.It was found that water in the gas atmosphere plays a significant role in the silicate anion equilibria.Water decreases the amount of free oxygen in the studied slags,with the free oxygen expressed as percentage of the total oxygen decreasing in the order of the following gas mixtures:CO+CO2(44%,pH2 O = 0 k Pa) CO+CO2+H2+H2O(41%,pH2 O = 10.13 k Pa) H2+H2O(37%,pH2 O = 14.19 k Pa).The content of free oxygen ion affects the distribution of elements such as sulfur,phosphorus,and manganese.In addition,it affects the iron oxide content in the slag as well as the interaction between slag and furnace lining.     

Preparation and characterization of Ce-Fe-Zr-O(x)/MgO complex oxides for selective oxidation of methane to synthesize gas

A series of Ce-Fe-Zr-O(x)/MgO(x denotes the mass fraction of Ce-Fe-Zr-O,x=10%,15%,20%,25%,30%) complex oxide oxygen carriers for selective oxidation of methane to synthesis gas were prepared by the co-precipitation method.The catalysts were characterized by means of X-ray diffraction and H2-TPR.The XRD measurements showed that MgFeO4 particles were formed and Fe2O3 particles well dispersed on the oxygen carriers.The reactions between methane diluted by argon(10% CH4) and oxygen carriers were investigated.Suitable content of CeO2/Fe2O3/ZrO2 mixed oxides could promote the reaction between methane and oxygen carriers.There are mainly two kinds of oxygen of carriers:surface lattice oxygen which had higher activity but lower selectivity,and bulk lattice oxygen which had lower activity but higher selectivity.Among all the catalysts,Ce-Fe-Zr-O(20%)/MgO exhibited the best catalytic performance.The conversion of the methane was above 56%,and the selectivity of the H2 and CO were both above 93%,the ratio of H2/CO was stable and approached to 2 for a long time.     

高炉喷吹煤气的煤造气试验

为克服喷吹煤粉给高炉冶炼带来的不利影响,提出了由造气炉燃烧普通煤产生煤气,自风口喷入高炉替代喷吹煤粉的新工艺,研究工艺参数对煤造气质量的影响规律。结果表明,气化剂流量增加,煤气中CO+H_2含量和煤气热值先升高后降低;CO+H_2含量和煤气热值随着反应温度、料层厚度、富氧率的增加而增加。当气化剂流量1.0 m~3/h、反应温度1 000℃、料层厚度1 000 mm、富氧率15%时,煤气质量达到最佳值,CO+H_2含量达到79.37%,煤气热值达到10 229.51 kJ/m~3。     

Study of welding technology on Baosteel high-strength heavy steel Bweldy620QL6

This study aims to conduct the weldability test for a high-strength structural steel,Bweldy620QL6,developed by Baosteel.This steel was subjected to welding,and the effects of two kinds of shielding gas,a binary gas of 80％ Ar + 20％ CO2 and ternary gas of 90％ Ar + 8％ CO2 + 2％ O2,on the performance of the welded joints of high-strength heavy steel were compared.The results show that Bweldy620QL6 has good weldability,and the joints obtained using binary gas and ternary gas meet common requirements.     

Influence of shielding gas on the transfer behavior of droplets

High-speed photography is utilized to capture an image of the arc area during the welding process.The variation in arc shape and droplet transfer behavior is compared when employing shielding gases of different components and proportions(e.g.,80％Ar+20％CO2,85％Ar+10％CO2+5％O2,65％Ar+26.5％He+8％CO2+0.5％O2)using a φ1.2 mm welding wire under 360 A current.Furthermore,the effects of various shielding gas components on the stability of the welding process are discussed.It was determined that the addition of oxygen and helium changed the arc's shape and the behavior of the droplet transfer,and the welding process stability increased.     

Stoichiometry of methane oxidation in the methane-oxidizing strain M 102 under the influence of various CH4/O2 mixtures

In laboratory-scale experiments with growing cells of the obligate methane-oxidizing strain M 102, an overall molar gas turnover ratio of the order given below could be postulated: 1 CH4+1--1.2 O2=0.3 CO2+water. Expectations that the optimal gas mixture of methane and oxygen should lie within the range of this stoichiometric consumption ratio have been verified in fermenter 5 1 batch culture experiments. The optimal range of methane-oxygen mixture, found under the experimental conditions described, is based on the estimated growth parameters as generation and doubling times, yield coefficients related to methane and oxygen, and the efficiency of methane metabolism as indicated in the absolute amounts of CH4, O2, and CO2 turned over. The mentioned stoichiometric relation of 1 CH4:1--1.202 did not change with varying the composition, i.e. the partial pressures of CH4 and O2 introduced as a mixture to the cells. The efficiency of methane oxidation was obviously influenced and decreased markedly when deviating from the broad optimal range of CH4/O2 mixtures. With non-growing cells, on the other hand, the stoichiometric relation showed a considerable shift (1:1.4--1.8 CH4:O2) with a clear tendency towards more O2 consumption. The oxidation potential of growing cells, seems then to have a linear interdependence to the substrate concentrations, i.e. partial pressures.     

A thermodynamic evaluation of nitrocarburizing atmospheres

Knowledge of the thermodynamics of ammonia reforming in complex gases should be valuable for the control of nitrocarburizing processes. In this papersome gas mixtures based on N + H + O and/or N + H + O + C systems are discussed. From the equilibrium behaviour of these gas mixtures the nitrogen potential can be derived. The relations relevant to the application of measurement with oxygen sensors are shown and some errors due to the use of published equations are indicated. The calculation of the gas chemistry was made by a mathematical model named GPRO, developed by the authors, together with a specially determined data base for complex gaseous atmospheres.