| Coke oven gas (COG) is a byproduct of the coking process, and it is a high quality fuel and chemical raw material. However, tar in COG will cause a lot of problems, such like clogging pipes, corrosion of equipment, environment pollution and other issues. Ammonia washing method is the traditional method for removing tar, but this method can not use the energy carried by COG and cause water pollution. Catalytic cracking of tar has been a hot topic at home and abroad, because it can remove tar and enhance the heat value of COG. However, tar cracking process will generate a lot of deposited carbon, which deposits on the catalyst surface and make the catalyst inactivate. This research takes use of sinter ore, which is common in steel enterprises as catalyst for tar cracking. Deposited carbon can be used as reductant for ironmaking, and cracking of tar can enhance total heat of COG, this method can take full advantage of energy carried by COG and sinter ore. Conclusions are as followings:(1) This research analyzes the cracking effect of tar by using sinter ore as catalyst, and experimental equipment is fixed bed reactor. In the case of controlling height of sinter ore, this paper studys the influence caused by the reaction temperature, tar amount per unit time, particle size of the sinter ore and the effect of water added into the tar cracking process. The height of sinter ore layer is7cm, mass is about90g. Reaction temperature is500℃,600℃,700℃,800℃; Amount of tar added in is0.3g/min,0.5g/min and0.7g/min; Particle sizes of sinter ore are2-4mm and4-7mm. When considering effect of water for tar cracking, a fixed amount of water0.35g/min is added in. Experimental results show that with reaction temperature increasing, the amount of gas generated per unit mass tar cracking increases rapidly, especially between700and800℃, it shows that high temperature is conducive to cracking of tar. With the amount of tar added in increasing, the amount of gas generated per unit time of tar cracking increases, but the amount of gas generated per unit mass of tar cracking decreases. With the particle size of sinter ore increasing, amount of gas generated per unit mass and per unit time of tar cracking decreases. When water was added into the tar cracking process, amount of gas generated per unit mass and per unit time of tar cracking increases, especially CO and H2.(2) This paper makes thermodynamic analysis of the process of purification and reforming of COG using sinter ore by Aspen Plus. Thermodynamic analysis assumes that the heat which COG reforming and tar cracking needed is provided by the outside. Thermodynamic analysis mainly studys the effect of reaction temperature, water carbon ratio, iron carbon ratio and reaction pressure on the balance of COG reforming and tar cracking. Simulation results show that high temperature is conducive to H2and CO, the higher the reaction temperature, the more heat COG carrys. High water carbon ratio is conducive to CH4converted to CO and H2, and reduces the deposited carbon. Changing water carbon ratio can effectively regulate compositions of the reforming COG. Iron carbon ratio has a important influence on CH4, H2and CO, the higher iron carbon ratio is, the less heat COG carrys. High reaction pressure is not conducive to conversion of methane and tar, however, higher reaction pressure will make heat value of COG higher.(3) This paper makes thermal equilibrium process of purification and reforming of COG using sinter ore by Aspen Plus. Thermal equilibrium process assumes that the heat which COG reforming and tar cracking needed is provided by their physical sensible heat. Thermal equilibrium process mainly studys the effect of amount of sinter ore added in, initial temperature of sinter ore, initial temperature of COG, water carbon ratio and reaction pressure on the balance of COG reforming and tar cracking. Simulation results show that the amount of sinter ore is conducive to H2and CO, and can reduce the deposited carbon. Higher the initial temperature of sinter ore and COG is, higher the balance temperature is. High initial temperature of sinter ore and COG is conducive to CH4and tar converted to CO and H2, thus making the total heat COG carrying increases. High water carbon ratio is conducive to reduce the deposited carbon and CH4and tar converted to CO and H2. Water carbon ratio increasing will improve the total heat of COG significantly; when water carbon ratio is lower than1.5. The higher the reaction pressure is, the higher the equilibrium temperature is, the lower amount of CO and H2is. High reaction pressure can increase heat value of COG. |
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