Effect of Cr2O3 addition on oxidation induration and reduction swelling behavior of chromium-bearing vanadium titanomagnetite pellets with simulated coke oven gas

The oxidation induration and reduction swelling behavior of chromium-bearing vanadium titanomagnetite pellets(CVTP)with Cr2O3 addition were studied,and the reduction swelling index(RSI)and compressive strength(CS)of the reduced CVTP with simulated coke oven gas(COG)injection were investigated.The results showed that the CS of the CVTP decreases and the porosity of the CVTP increases with increasing amount of Cr2O3 added.The Cr2O3 mainly exists in the form of(Cr,Fe)2O3 solid solution in the CVTP and as Fe-Cr in the reduced CVTP.The CS of the reduced CVTP increases and the RSI of the reduced CVTP decreases with increasing amount of Cr2O3 added.The limited aggregation and diffusion of metallic iron contribute to the formation of dense lamellar crystals,which leads to the slight decrease for reduction swelling behavior of reduced CVTP.This work provides a theoretical and technical basis for the utilization of CVTP and other Cr-bearing ores such as chromite with COG recycling technology.

Partial oxidation of simulated hot coke oven gas to syngas over Ru-Ni/Mg(Al)O catalyst in a ceramic membrane reactor

Hydrogen amplification from simulated hot coke oven gas （HCOG） was investigated in a BaCo0.7Fe0.2Nb0.1O3-δ （BCFNO） membrane reactor combined with a Ru-Ni/Mg（Al）O catalyst by the partial oxidation of hydrocarbon compounds under atmospheric pressure. Under optimized reaction conditions, the dense oxygen permeable membrane had an oxygen permeation flux around 13.3 ml/（cm^2·min）. By reforming of the toluene and methane, the amount of H2 in the reaction effluent gas was about 2 times more than that of original H2 in simulated HCOG. The Rn-Ni/Mg（Al）O catalyst used in the membrane reactor possessed good catalytic activity and resistance to coking. After the activity test, a small amount of whisker carbon was observed on the used catalyst, and most of them could be removed in the hydrogen-rich atmosphere, implying that the carbon deposition formed on the catalyst might be a reversible process.

Perovskite-type oxygen-permeable membrane BaCo_(0.7)Fe_(0.2)Nb_(0.1)O_(3-δ) for partial oxidation of methane in coke oven gas to hydrogen

Perovskite-type oxygen-permeable membrane reactors of BaCo0.7Fe0.2Nb0.1O3-δ （BCFNO） packed with Ru-based catalyst had high oxygen permeability and could be used for hydrogen production by partial oxidation of methane in coke oven gas （COG）. At 1173 K, 94% of methane conversion, 85% of H2 selectivity, 107% of CO selectivity, and as high as 15.4 mL·cm^-2·min^-1 of oxygen permeation flux were obtained. The BCFNO membrane itself had poor catalytic activity to partial oxidation of CH4 in COG. During continuous operation for 70 h at 1173 K, no degradation of the membrane reaction performance was observed. XRD and SEM characterization also demonstrated that the BCFNO membrane reactor exhibited good stability in partial oxidation of methane in COG.

Performance of a tubular oxygen-permeable membrane reactor for partial oxidation of CH_4 in coke oven gas to syngas

A gas-tight BaCo 0.7 Fe 0.2 Nb 0.1 O 3-δ（BCFNO） tubular membrane was fabricated by hot pressure casting.And a membrane reactor with BCFNO tubular membrane and Ag-based sealant was readily constructed and applied to partial oxidation of CH4 in coke oven gas.At 875 ℃,95% of methane conversion,91% of H 2 and as high as 10 ml cm-2·min-1 of oxygen permeation flux were obtained.There was a good match in the coefficient of thermal expansion between Ag-based alloy and BCFNO membrane materials.The tubular BCFNO membrane reactor packed with Ni-based catalysts exhibited not only high activity but also good stability in hydrogen-enriched coke oven gas（COG） atmosphere.

Hydrogen production via chemical looping reforming of coke oven gas

Coke oven gas(COG)is one of the most important by-products in steel industry,and the conversion of COG to value-added products has attracted much attention from both economic and environmental views.In this work,we use the chemical looping reforming technology to produce pure H_(2) from COG.A series of La1-xSrxFeO_(3)(x?0,0.2,0.3,0.4,0.5,0.6)perovskite oxides were prepared as oxygen carriers for this purpose.The reduction behaviors of La1-xSrxFeO_(3) perovskite by different reducing gases(H_(2),CO,CH4 and the mixed gases)are investigated to discuss the competition effect of different components in COG for reacting with the oxygen carriers.The results show that reduction temperatures of H_(2) and CO are much lower than that of CH4,and high temperatures(>800℃)are requested for selective oxidation of methane to syngas.The co-existence of CO and H_(2) shows weak effect on the equilibrium of methane conversion at high temperatures,but the oxidation of methane to syngas can inhibit the consumption of CO and H_(2).The doping of suitable amounts of Sr in LaFeO_(3) perovskite(e.g.,La0.5Sr0.5FeO_(3))significantly promotes the activity for selective oxidation of methane to syngas and inhibits the formation of carbon deposition,obtaining both high methane conversion in the COG oxidation step and high hydrogen yield in the water splitting step.The La0.5Sr0.5FeO_(3) shows the highest methane conversion(67.82%),hydrogen yield(3.34 mmol g^(-1))and hydrogen purity(99.85%).The hydrogen yield in water splitting step is treble as high as the hydrogen consumption in reduction step.These results reveal that chemical looping reforming of COG to produce pure H_(2) is feasible,and an O_(2)-assistant chemical looping reforming process can further improves the redox stability of oxygen carrier.

Hydrogen production from simulated hot coke oven gas by catalytic reforming over Ni/Mg(Al)O catalysts

Hydrogen production by catalytic reforming of simulated hot coke oven gas （HCOG） with toluene as a model tar compound was investigated in a fixed bed reactor over Ni/Mg（Al）O catalysts. The catalysts were prepared by a homogeneous precipitation method using urea hydrolysis and characterized by ICE BET, XRD, TPR, TEM and TG. XRD showed that the hydrotalcite type precursor after calcination formed （Ni, Mg）Al2O4 spinel and Ni-Mg-O solid solution structure. TPR results suggested that the increase in Ni/Mg molar ratio gave rise to the decrease in the reduction temperature of Ni^2＋ to Ni^0 on Ni/Mg（Al）O catalysts. The reaction results indicated that toluene and CH4 could completely be converted to H2 and CO in the catalytic reforming of the simulated HCOG under atmospheric pressure and the amount of H2 in the reaction effluent gas was about 4 times more than that in original HCOG. The catalysts with lower Ni/Mg molar ratio showed better catalytic activity and resistance to coking, which may become promising catalysts in the catalytic reforming of HCOG.

Influence of hydrogen-enriched atmosphere under coke oven gas injection on reduction swelling behaviors of oxidized pellet

It is of great importance to elucidate reduction swelling behaviors and reaction mechanism of oxidized pellet in hydrogen-enriched atmosphere under coke oven gas injection. In this work, the effects of hydrogen concentration in N_2-CO-H_2 atmosphere with unchanged CO content on reduction swelling behaviors of oxidized pellet at 1173 K were studied, to clarify the mechanism of hydrogen-enriched reduction and exclude the influences of CO. Then, the reduction swelling behaviors of oxidized pellet at 1173 K in actual atmosphere under coke oven gas(COG) injection, got from the simulation results of multi-fluid blast furnace model, were investigated. The results show that with the concentration of hydrogen increasing in N_2-CO-H_2 gas from 2% to 18%, the reduction swelling index of pellet decreases from 10.12% to 5.57% while the reduction ratio of pellet increases obviously from 39.85% to 69.58%. In addition, with COG injection rate increasing from 0 to 152.34 m^3/t, the reduction swelling index of pellet decreases slightly from 10.71% to 9.54% while the reduction ratio of pellet is increased from 31.57% to 36.39%. The microstructures of pellet are transformed from the platy structure to the flocculent structure.

Process Optimization of Coke Oven Gas to Methanol Based on the Downgrade of By-Product Steam

In the coke oven gas to methanol(CTM) process, boiling water(above 200 ℃) is generally used as the coolant in the methanol synthesis reactor, and thus, medium-pressure steam is generated as a by-product. In this paper, the influence of the coolant temperature on the CTM process is investigated from two aspects, which are the performance analyses of the reactor and the overall process and the energy integration of by-product steam. The results reveal that the coolant temperature plays a key role in the CTM process optimization. When the coolant temperature is reduced to 187 ℃, though low-pressure steam is generated, the techno-economic performance of the whole process is greatly improved: the energy/exergy efficiency is increased by 4-9%, energy cost is saved by 37.1%, income is increased by 5.4 M$/year, and the C02 emission is reduced by 21.3%.

On-site raw gas cut-off during the shut down of Baosteel phaseⅠcoke ovens

The preparation and implementation of raw coke oven gas cut-off, which was the key process involved with shutting down the Baosteel phase I coke ovens, were investigated, and the main technical points and countermeasures are presented.

焦炉煤气脱碳法及甲烷化法制液化天然气的生命周期环境影响分析

作为焦化副产品,焦炉煤气富含氢气和甲烷,采用焦炉煤气制液化天然气(LNG)已成为当前焦炉煤气利用的主要途径之一。为系统评估焦炉煤气制LNG工艺的能源消耗和环境影响,尤其是碳排放,本文采用生命周期评价方法对脱碳法和甲烷化法两种焦炉煤气制LNG工艺进行系统评价。结果表明,无论采用哪种方法,LNG生产阶段均为焦炉煤气制LNG工艺生命周期环境负荷的控制阶段;在脱碳法工艺中,中压蒸汽是环境影响贡献的关键物质,可通过干熄焦回收红焦余热副产蒸汽补充LNG生产消耗来降低环境负荷;在甲烷化工艺中,电力为主要贡献物质,在碳排放中占比41.09%,若采用可再生能源电力(太阳能发电、风电、水电)替代后环境影响显著降低;相比于脱碳法,采用甲烷化工艺环境性能更优,主要源于甲烷增产优势。本文研究结果可从生命周期角度为焦化行业焦炉煤气的综合利用提供理论支持。

焦炉煤气制合成天然气(SNG)分析

焦炉煤气的利用途径主要包括作为燃料气直接利用、发电、合成甲醇、合成氨或尿素、制氢、合成天然气等,通过对焦炉煤气不同利用途径的技术和经济可行性分析,提出了焦炉煤气制合成天然气,配套建设焦炉煤气合成甲醇或LNG方案。焦炉煤气的统一合理利用,符合大力深化转型综改的政策要求,满足发展循环经济、提高资源综合利用率的要求。既能够填补天然气供应的缺口,又能够起到一定的储气调峰作用,在促进焦化行业健康发展的同时,还能带来一定的经济效益、环境效益和社会效益。

Distribution of reformed coke oven gas in a shaft furnace

In recent years, the reformed coke oven gas (COG) was proposed to be used as reducing gas in a shaft furnace. A mathematical model of gas flow based on the reformed COG was built. The effects of the pressure ratio of reducing gas to cooling gas (k) on the gas distribution in the shaft furnace were investigated. The calculation results show that k is an important operation parameter, which can obviously affect the gas distribution in the shaft furnace. The value of k should be compromised. Both too big and too small k values are not appropriate, and the most reasonable value for k is 1:1.33.Under this condition, the utilization coefficient of reducing gas, the utilization coefficient of cooling gas and the coefficient of upward gas are 0.94, 0.92 and 1.03, respectively. Based on the validation of physical experiments, the calculated values of the model agreed well with the physical experimental data. Thus, the established model can properly describe the reformed COG distribution in an actual shaft furnace.

Catalytic performance of Co-Mo-Ce-K/γ-Al_(2)O_(3) catalyst for the shift reaction of CO in coke oven gas

The catalytic performance of Co-Mo-Ce-K/γAl_(2)O_(3) catalyst for the shift reaction of CO in coke oven gas is investigated using X-ray diffraction(XRD)and temperature-programmed reduction(TPR).The results indicate that Ce and K have a synergistic effect on promoting the catalytic activity,and the Co-Mo-Ce-K/γAl_(2)O_(3) catalyst with 3.0 wt-%CeO2 and 6.0 wt-%K_(2)O exhibits the highest activity.CeO2 favors Co dispersion and mainly produces an electronic effect.TPR characterization results indicate that the addition of CeO2-K_(2)O in the Co-Mo-Ce-K/γ-Al_(2)O_(3) catalyst decreases the reduction temperature of active components,and part of octahedrally coordinated Mo6+transforms into tetrahedrally coordinated Mo6+,which has a close relationship with the catalytic activity.

Development and application of coke oven gas spraying on sinter bed

The Shanghai Meishan Iron and Steel Co., Ltd. has a large supply of coke oven gas (COG) and has the potential to develop and apply the spraying of COG on the surface of a sinter bed. The effects of the amount of COG, the spraying time, and the spraying distribution with the process on the quantity and quality indexes of sinter were investigated in the laboratory experi-ments. The results showed that the COG spraying can improve the sinter indexes to a large extent if appropriate parameters were used. It was found that an appropriate amount of COG, a relatively long spraying time, and a decreasing distribution of the COG amount with the spraying process all help to obtain a better performance for sinter quantity and quality indexes. When the COG spraying was applied to the No. 3 sintering machine, the sinter tumbler index increased by 0.45%, the overall finished product rate increased by 0.72%, the solid fuel consumption decreased by 4.06kg/t, the reducibility increased by 3.89%, and the cost of iron decreased by 5.29 CNY/t, and the CO2, SO2 and Nox emissions also decreased, thus proving the feasibility of this technology. Therefore, COG spraying provides a new way to improve sinter and also decrease the energy consumption and pollution.

Sensitivity analysis of a methanol and power polygeneration system fueled with coke oven gas and coal gas

The sensitivity analysis of a polygeneration energy system fueled with duo fuel of coke oven gas and coal gas is performed in the study,and the focus is put on the relations among syngas composition,conversation rate and performance.The impacts of the system configuration together with the fuel composition on the performance are investigated and discussed from the point of cascading utilization of fuel chemical energy.First,the main parameters affecting the performance are derived along with the analysis of the system configuration and the syngas composition.After the performance is being simulated by means of the Aspen Plus process simulator of version 11.1,the variation of the performance due to the composition of syngas and the conversion rate of chemical subsystem is obtained and discussed.It is obtained from the result that the proper conversion rate of the chemical subsystem according to the specific syngas composition results in better performance.And the syngas composition affects the optimal conversion rate of the chemical subsystem,the optimal point of which is around the stoichiometric composition for methanol production(CO/H_(2)=0.5).In all,the polygeneration system fueled with coke oven gas and coal gas,which can realize the reasonable conversion of syngas to power and chemical product according to the syngas composition,is a promising method for coal energy conversion and utilization.

炼焦煤中直接添加含铅锌冶金粉尘的焦炉煤气脱硫研究

将含铅锌冶金粉尘直接添加到炼焦煤中实现煤气脱硫的新技术 ,使得焦炉煤气脱硫不需要添加专门的脱硫设备成为可能 ,并可同时完成含铅锌冶金粉尘的回收利用 .研究结果表明 ,在加入的冶金粉尘中的Zn和Pb的摩尔数与挥发出的硫的摩尔数之比大于 1的条件下 ,煤气中的硫可以完全脱除 ,并且焦炭的质量与未加入含铅锌冶金粉尘的没有区别 ,焦炭的收得率没有降低 .

高炉喷吹焦炉煤气操作的㶲分析

基于分析理论,建立高炉喷吹焦炉煤气分析模型,系统地研究焦炉煤气喷吹量对高炉损失、热力学完善度和效率的影响,提出高炉喷吹焦炉煤气操作条件下能量利用再优化的途径。研究结果表明:高炉的输入主要为燃料的化学和热风物理;输出主要为铁水的物理和化学、高炉煤气化学以及内部损失;与未喷吹操作相比,当喷吹量为11.89 m3/s时,内部损失和总损失分别降低26.38%和3.98%,外部损失升高2.11%,喷吹焦炉煤气对减少高炉内部的损失更为明显;喷吹焦炉煤气后,高炉的热力学完善度由90.23%上升到92.65%,效率由53.39%上升到54.25%,能量利用的质量得到提高;喷吹焦炉煤气后,铁水和炉渣的物理和化学相对稳定,吨铁炉顶煤气的化学由4.60增加到4.97 GJ,应加强这部分的利用。

高炉喷吹焦炉煤气风口回旋区的数学模拟

基于质量平衡和热量平衡理论,建立了高炉喷吹焦炉煤气风口回旋区数学模型,系统研究了焦炉煤气喷吹量对回旋区焦炭质量流量、理论燃烧温度、炉腹煤气量、炉腹煤气组成和回旋区形状的影响.研究表明:在维持高炉现有的基准操作不变的条件下,随着焦炉煤气喷吹量的增加,理论燃烧温度呈降低的趋势,而炉腹煤气量呈增加的趋势;为了维持理论燃烧温度和炉腹煤气量与基准操作一致,可通过降低风量和提高富氧率进行热补偿.热补偿后,随着焦炉煤气喷吹量的增加,焦炭质量流量呈上升趋势,炉腹煤气中还原气体积呈增加趋势,回旋区体积呈缩小趋势.每增加1 m3/s的焦炉煤气喷吹量,焦炭质量流量上升1.74%,炉腹煤气中还原气体积增加2.04%,回旋区体积缩小1.98%.

焦化行业脱硫工艺多级模糊综合评价

针对目前应用最为广泛的8种焦化脱硫工艺,采用多级模糊数学模型,对焦炉煤气脱硫工艺进行了综合评价。模糊评价的因素集由环境指标、经济指标和技术指标三大类因素构成,其中每一因素集又包括更具体的评价指标;通过确定各具体性能指标的隶属函数,并应用层次分析法(AHP)确定各因素集的权重矩阵,对每一大类因素进行初级综合评价,进一步在初级评价结果基础上进行二级模糊综合评价。结果表明,根据最大隶属度原则,PDS+栲胶法是综合性能最优的焦化脱硫工艺。

用焦炉气生产液化天然气的制冷循环

经过净化的焦炉气(COG)通过甲烷化反应,使CO和CO2转化成甲烷,COG中原有的组分H2、N2、CO、CO2、CH4、CmHn系统,变成H2、N2、CH4系统。本文提出了用低温分离的方法将CH4与H2、N2分离,得到纯度(体积分数)99.5%以上的甲烷,并再进行液化,得到液体甲烷(LNG)的工艺流程,并评述了采用产品甲烷作为制冷剂的带有预冷的后置式甲烷绝热膨胀制冷循环及带有预冷的高压甲烷二次节流制冷循环。