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In order to reduce SO2 emission in the iron sintering process, the flue gas circulation sintering (FGCS) process has been recommended and put into practice. In this process, flue gas containing low SO2 concentration is recirculated to the sintering process, achieving the concentration of SO2 content in the off-gas, which is favorable for current flue gas desulphurization processes. In this study, SO2 behavior in different sintering zones was investigated under the simulated experimental conditions. In the moisture condensation zone and sinter mixture zone, SO2 of recirculated flue gas is absorbed by the moisture and slaked lime of sinter mixture; in the drying and preheating zone, part of SO2 in circulating flue gas is absorbed by dry slaked lime in sinter mixture under low temperature conditions, and SO2 is generated by oxidization of sulfides and re-released by decomposition of sulphurous acid; in the hot zone, SO2 in circulated gas is partially absorbed by the molten phases, newly crystallized minerals such as calcium ferrite and dissociative CaO; in sinter zone, part of SO2 is absorbed by residual CaO in sinter under the condition of humid circulated flue gas, which results in unfavorable increase of residual S in the up layer sinter.

Sulfur dioxide is one of the precursors of acid rain and desulfurization of the exhaust gases in iron ore sintering plants is essential. For the purpose of reducing SO2 emissions of iron ore sintering, flue gas circulation sintering (FGCS) process was employed to enrich SO2 content in off-gas in this work. Effects of simulated flue gas components involving O2, CO, SO2 and H2O(g) content and temperature on iron ore sintering properties were investigated in a laboratory scale sinter pot. Experimental results show that, compared with the conventional sintering process, the sinter quality became obviously worse when the O2 content in inlet gas was less than 18%. The presence of CO in inlet gas improved the sintering properties, so did the sensible heat of the heated inlet gas. However, either an excessive SO2 content of more than 1 000 ppm or H2O content of more than 5% in inlet gas would be detrimental for sintering and results in the sulfur retention in finished sinter. Thus, in the practice of FGCS, it is necessary to add O2 content up to no less than 18%, and keep H2O content less than 5% in the circulated flue gas. Beside, FGCS process is capable of enriching SO2 in off-gas with a peak value of 2 006 ppm when the SO2 content of inlet gas was 500 ppm, while the maximum SO2 content was 1 256 ppm in the conventional sintering process. SO2 concentrated in off-gas is more readily to be captured by the current flue gas desulfurization (FGD) technologies.

Different from cloud computing, edge computing moves computing away from the centralized data center and closer to the end-user. Therefore, with the large-scale deployment of edge services, it becomes a new challenge of how to dynamically select the appropriate edge server for computing requesters based on the edge server and network status. In the TCP/IP architecture, edge computing applications rely on centralized proxy servers to select an appropriate edge server, which leads to additional network overhead and increases service response latency. Due to its powerful forwarding plane, Information-Centric Networking (ICN) has the potential to provide more efficient networking support for edge computing than TCP/IP. However, traditional ICN only addresses named data and cannot well support the handle of dynamic content. In this article, we propose an edge computing service architecture based on ICN, which contains the edge computing service session model, service request forwarding strategies, and service dynamic deployment mechanism. The proposed service session model can not only keep the overhead low but also push the results to the computing requester immediately once the computing is completed. However, the service request forwarding strategies can forward computing requests to an appropriate edge server in a distributed manner. Compared with the TCP/IP-based proxy solution, our forwarding strategy can avoid unnecessary network transmissions, thereby reducing the service completion time. Moreover, the service dynamic deployment mechanism decides whether to deploy an edge service on an edge server based on service popularity, so that edge services can be dynamically deployed to hotspot, further reducing the service completion time.

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