1000 MW燃煤机组尿素制氨系统选择与经济性分析

Selection and Economic Analysis of Ammonia Production System in 1000 MW Coal-Fired Units

某电厂二期拟建2×1000 MW燃煤机组,锅炉尾部采用选择性催化还原脱硝工艺(SCR)。为了确定尿素制氨系统类型,分别调研了电加热尿素热解系统、气气换热尿素制氨系统、尿素普通水解系统、尿素催化水解系统。技术上,尿素水解制氨系统在机组高(低)负荷运行、施工、检修、故障、腐蚀、堵塞、安全性等方面具有一定优势。经济上,尿素热解制氨系统固定投资与尿素水解的相当,两者差别一般在10%以内,且多数情况尿素水解系统固定投资花费较低;4种尿素制氨系统运行费用分别为2259万元/a、1994万元/a、2012万元/a、1885万元/a,尿素催化水解系统年运行费用最低且较尿素普通水解系统的低127万元。因为尿素催化水解制氨系统中蒸汽、电、除盐水等费用占运行费用的比例仅为10.07%、1.07%、0.11%,同时其尿素分解率≥99%。综合考虑技术和经济2个层面因素,宜推荐尿素催化水解制氨系统。本分析方法对同类系统选择具有参考意义。

A power plant plans to build 2×1000 MW coal-fired units in the second phase,and selective catalytic reduction denitration process(SCR)is adopted at the tail of boiler.In order to determine the type of ammonia production system,the urea pyrolysis system of electric heating,urea pyrolysis system of gas-gas heating exchange,common urea hydrolysis system,catalytic urea hydrolysis system are investigated.Technically,urea hydrolysis system has certain advantages in high(low)load operation,construction,maintenance,failure,corrosion,blockage,safety and other aspects.The fixed investment of urea pyrolysis ammonia production system is similar to that of urea hydrolysis,and the difference between the two is generally within 10%,and the fixed investment cost of urea hydrolysis system is low in most cases.The operating costs of the four urea ammonia production systems are 22.59 million yuan/a,19.94 million yuan/a,20.12 million yuan/a and 18.85 million yuan/a respectively.The annual operating costs of catalytic urea hydrolysis system are the lowest,1.27 million yuan lower than that of common urea hydrolysis system.This is because that steam,electricity and desalinization costs account for only 10.07%,1.07%and 0.11%of operating costs in catalytic urea hydrolysis system,and the rate of urea decomposition is more than 99%.Considering both technical and economic factors,the catalytic urea hydrolysis system should be recommended.This analysis method has reference significance for the selection of similar systems.