国产300 MW机组综合升级改造的实践

通过对某发电厂11号机组汽轮机、锅炉效率低及供电煤耗高的问题进行分析,制定综合升级改造方案。改造内容包括:汽轮机通流部分改造、无烟煤改烧烟煤、磨煤机出口分离器改造、降低锅炉排烟温度改造、一次风机高压变频改造等。机组实施综合升级改造后,运行情况稳定,汽轮机效率、锅炉效率明显提高,供电煤耗大幅下降,取得了良好的经济效益和社会效益。     

A Non-Forced-Write Atomic Commit Protocol for Cluster File Systems

Distributed metadata consistency is one of the critical issues of metadata clusters in distributed file systems. Existing methods to maintain metadata consistency generally need several log forced write operations. Since synchronous disk IO is very inefficient, the average response time of metadata operations is greatly increased. In this paper, an asynchronous atomic commit protocol （ACP） named Dual-Log （DL） is presented. It does not need any log forced write operations. Optimizing for distributed metadata operations involving only two metadata servers, DL mutually records the redo log in counterpart metadata servers by transferring through the low latency network. A crashed metadata server can redo the metadata operation with the redundant redo log. Since the latency of the network is much lower than the latency of disk IO, DL can improve the performance of distributed metadata service significantly. The prototype of DL is implemented based on local journal. The performance is tested by comparing with two widely used protocols, EP and S2PC-MP, and the results show that the average response time of distributed metadata operations is reduced by about 40%-60%, and the recovery time is only I second under 10 thousands uncompleted distributed metadata operations.     

韶关发电厂200MW汽轮机低压缸通流部分改造

阐述了200MW汽轮机低压缸通流部分改造的主要工艺，并对改造过程中具体问题提出处理办法。经过改造前后的性能试验对比表明，汽轮机低压缸改造后的性能有大幅度提高。