Product Distribution During Fast Coking Process Of Coal Under N₂/N_2CO₂/N_2H2O Atmosphere

Energy consumption in China is still dominated by coal because of the current energy structure.In order to solve this problem,Shenhua Group launched the“Sulfur Recovery and Resource Utilization Technology for Coal-fired Flue Gas”project.The project uses pulverized coal in power plants to produce activated coke,which can absorb SO₂ and recover sulfur resources by some means.Not only this project can reduce the environmental pollution,but also it can alleviate scarcity of sulfur resources.However,the comprehensive studies on the products in the high-temperature rapid coking process are few and the tar and gas products can be neglected in the coke making process.The tar can cause dangers in many ways,the most common kind of which is clogging pipes by condensation.The gas product can be reused,so its calorific value is also worth considering.To solve this problem,comprehensive research on the products in the high-temperature rapid coking process has been studied.The results can also present the optimum conditions for the new coking reactor.Firstly,the high-volatility coal was subjected to fast coking experiments under inert atmosphere.The yield and related properties of the three-phase products under dofferent reaction temperature and reaction residence time were studied.Secondly,CO₂ and H₂O were added as activators to the inert atmosphere,and the changes of reaction temperature,reaction residence time and activator concentration on each product were studied,and the better application conditions were summarized.Studies on the specific surface area characteristics show that increasing the reaction temperature and reaction residence time in high-temperature rapid coking reduce the yield of the coke and promote the formation of pore structure in the coke,resulting in an increase in specific surface area,but the pore structure will be destroyed at over-high temperature.The specific surface area of the coke is reduced;both CO₂ and H₂O have a favorable effect on the specific surface area,and from the experimental results,the activation effect of CO₂ is slightly better than that of H₂O,and the increase of the concentration of the activator can continue to increase the specific surface area of coke.Studies on the yield and properties of tar show that the increase of reaction temperature and reaction residence time can reduce the yield of tar,and the addition of CO₂ and H₂O can further inhibit the formation of tar,and H₂O can do better.The main products of tar in the process are mainly aromatic hydrocarbons,and with the increase of reaction temperature,the types of tar substances decrease,the even oscillation of tar substances increases,the content of aromatic hydrocarbon derivatives decreases,and the content of high-boiling substances increases.Under the N_2CO₂ atmosphere,the tar produced more components with higher boiling point.However,due to the inhibition of the dehydrogenation and cyclization of the water vapor,the heavy component content in tar is relatively low,which is beneficial to the fluidity of tar.Studies on gas products show that the gas yield increases with the increase of reaction temperature,reaction residence time and activator concentration,but the calorific value of gas decreases.The addition of CO₂ can effectively increase the calorific value of gas products.In the high temperature and fast coking in drop tube furnace at 800-1100?,the better low tar conditions obtained under three kinds of atmosphere are as follows:under N₂atmosphere,experimental temperature is 1100?and residence time is 5 s;under N_2CO₂atmosphere,experimental temperature is 1000?and the proportion of CO₂ is 30%;under N_2H2O atmosphere,experimental temperature is 1100?,residence time is 5s and water intake is 2-3.5 ml/min.