Experimental Study of Direct Water Injection Effect on NOx Reduction from The Gas Fuel

Abstract

Direct Water Injection (DWI) is commonly used in many nitrogen oxides (NOx) emissions control applications due to its effect to reduce the adiabatic flame temperature. In this paper an experimental test rig is designed to study the effect of water injection spray inside a simulated gas turbine combustor from the gas fuel. The practical work introduced by the chemical reaction methodology followed by the experiment which was presented and discussed carefully. Results are obtained in term of the exhaust gas temperature and different injection parameters including position, direction and fuel mass flow rate on the nitrogen oxide emission value in PPM (Parts per Million) at different conditions. The results showed that the best water injection effect was obtained at 45° degree inside the primary air zone. Injection location has a major effect on the NOx reduction as the best injected location is the Primary air zone compared with the direct fuel nozzle tip due to the increase of the water droplets residence time inside the combustor and perform a vortex that will affect the reduction of exhaust gas temperature and NOx emission respectively. The huge impact was observed at LPG (Liquefied Petroleum gas) flowrate 2.7L/min and water to fuel ratio about 0.4 as the NOx value was decreased about 73% from almost 381 PPM to 73 PPM. The chemical reaction arrangement order methodology presented good agreement with the experimental results at different fuel flow rate and equivalence ratio. The chemical Reaction equations were implemented to calculate the different adiabatic flame temperatures which is experimentally known as the exhaust gas temperature and impacted directly the NOx emission results.