Development of High Turbulence BGR Ultra-low NOx Combustor for Liquid Fueled Micro Gas turbine

微型燃气轮机系统是目前国内一家能源厂备受关注的系统。对于燃料的观点，即使在地震等紧急情况下，使用液体燃料的能源工厂也是可取的，因为它安全且燃料供应顺利。此外，在工厂的日常使用中，能源工厂的燃烧排放应该降至最低。超低NOx液体煤油燃烧器是为此开发的微型燃气轮机燃烧器。开发的燃烧室有一种独特的流动系统，称为向上旋流。这种流动可以形成燃烧气体再循环的向上逆流，对高湍流度的火焰稳定是有效的。利用BGR的作用实现低NOx燃烧也是有效的。本文取得的主要结果如下。(1)主燃区长度较长，导致CO、NOx等不良燃烧增加，火焰稳定性差。(2)涡流发生器叶片倾角的影响不大，但取消涡流发生器后，HC和CO排放增加。(3)在一次燃烧区底部设置导流片对火焰有很强的稳燃作用。为了稳定火焰，需要有足够的叶片高度。此外，为了稳定火焰，需要在主燃区出口处有足够大的喉部直径。(4)对燃烧室的主燃区、涡流发生器、导流片和出口喉部的尺寸进行了优化，使燃烧室具有足够的排放性能。在一次过量空气系数为1.5~1.6的条件下，NOx排放指数小于0.8g/(kg燃料)，CO排放指数小于10g/(kg燃料)

Micro gas turbine system is now received much attention for a local energy plant. As for the viewpoint of fuel, an energy plant using liquid fuel is desirable because of safety and smooth fuel supply even id the emergency situation such as earthquake. Also combustion emission from energy plant should be minimized for daily use of the plant. Ultra low Nox combustor with liquid kerosene fuel is developed as a micro gas turbine combustor for this purpose. The developed combustor has a unique flow system that is called upward swirl flow. This flow can form the upward reverse flow with burned gas re-circulation and is effective for flame stabilization with high turbulence. Also it is effective to attain a low Nox combustion by the effect of BGR. The main results obtained here are as follows. (1) Longer length of primary combustion zone results the undesirable combustion such as CO and Nox increases and low stability of flame. (2) The effect of vane angle of the swirl generator is not so much, however HC and CO emissions increase when the swirl generator is eliminated. (3) Air guide vane set at the bottom end of primary combustion zone shows the strong effect on the flame stabilization. For flame stabilization, enough height of vane is needed. Also an enough size of throat diameter at the outlet of primary combustion zone is needed for flame stabilization. (4) An optimization among the size of primary combustion zone, swirl generator, air guide vane and outlet throat results the enough emission performance of the combustor. Nox emission index less than 0.8 g/ (kg-fuel) and CO emission index less than 10 g/ (kg-fuel) can be attained under the primary excess air ratio of 1.5 〜 1.6