中国固定式燃气内燃机环境管理的形势、问题和对策

Develop status,difficulties and countermeasures of stationary gas internal combustion engine in China

固定式燃气内燃机是实现碳减排富有成效的技术方案之一,但其相应的环境管理略滞后,应尽快制定固定式燃气内燃机排放标准,且在环境管理体系中明确固定式燃气内燃机“非正常情况”下的达标判定依据。典型机组在线监测结果显示,监测期间NO_(x)排放小时质量浓度介于0~305 mg/m^(3);NO_(x)与CO均出现不同程度的排放超标现象,超标小时数分别为61、4 h,分别占有效小时数的9.8%、0.6%;NH_(3)质量浓度为0.94 mg/m^(3),排放达标。结果表明,选择性催化还原技术(SCR)系统与生产设备不同步投运是造成内燃机启动、停机阶段NO_(x)超标的主要原因;SCR催化剂老化是正常运行时段NO_(x)排放超标的主要原因。通过优化SCR系统停机控制调整逻辑、增加SCR催化床层厚度有望解决以上两个原因引起的NO_(x)超标问题。“调峰模式”“调负荷不停机”两种运行情景的NO_(x)日排放量分别为9.5、11.4 kg,前者环境效益明显。研究结果能为生态环境部门提高固定式燃气内燃机NO_(x)排放监管的科学性、有效性提供参考。

Stationary gas internal combustion engine would provide an efficient way to reduce carbon emissions,but its environmental management is delayed.It is recommended to clarify the emission standards of air pollutants and judgement of“abnormal circumstances”for stationary gas internal combustion engines.The emission characteristics of a typical units was analyzed,it was showed that the hourly concentration of NO_(x)was 0-305 mg/m^(3),and the hours for NO_(x)and CO emission concentrations exceeding standard were 61 and 4 h,accounting for 9.8%and 0.6%of the effective hours,respectively.Also,the NH 3 concentration was 0.94 mg/m^(3),which met the emission standard.The results indicated that the reasons for NO_(x)emission concentration exceeding standard during the start-up and shut down stages were that SCR denitration system being operating non-simultaneously with the electric generator;that for NO_(x)emission concentration exceeding standard during normal operation was the aging performance of catalysts.The optimization of control logic scheme for SCR denitration system and increasing of catalytic depth could solve the problem of NO_(x)emission concentration exceeding standard mentioned above.The emissions of“peak regulation mode”and“load transferring without interruption of power supplying”were calculated,the results showed that the daily NO_(x)emissions were 9.5 and 11.4 kg,respectively,which indicated that the former had a better environmental benefit.The research results provide references for government management departments to improve the scientificity and effectiveness of supervision for stationary gas internal combustion engine.