35 7 th Asia DME Conference November 16-18, 011 Niigata Toki Messe Convention Center, Niigata, Japan Low Combustion of DME by Exhaust Gas Recirculation under the High Pressure *Hiroaki TAKEUCHI Mamoru OZAWA Ryosuke MATSUMOTO *Dept. of Mech. Eng., Kansai University
The research purpose and its back ground The application of DME to boiler and gas turbine And The utility of reduction by exhaust gas recirculation The application of DME and EGR to boiler Exhaust gas Air The reduction by EGR was successful on this project. DME Hirakawa Guidam Co.ltd The fundamental characteristics of DME combustion with EGR at high pressure
Physical properties of DME DME Propane Methane Chemical formula CH 3 OCH 3 C 3 H 8 CH 4 Liquid density kg/m 3 0.67 0.49 N.A. Boiling point K (at0.1mpa) 48 31 11 Saturated vapor pressure MPa (at98k) 0.61 0.93 4.6 Adiabatic flame temperature K 7 50 36 Burning velocity cm/s 50 43 37 Ignition temperature K 63 743 93 Pre-mixed combustion Low thermal emission Flash back Diffusion combustion High thermal emission No flash back
reduction by EGR Exhaust gas Mass recirculation Low emission BUT Unstable combustion Exhaust gas + Air Fuel Air Enthalpy recirculation Stable combustion
Experimental setup Oxygen concentration of combustion air Mixing N into combustion air Temperature of combustion air Preheating the diluted air with electrical heater EGR ratio Flow rate of recirculation exhaust Flow rate of air gas Diluted air 1% Diluted air O O % Exhaust % gas O %
Combustion chamber Fuel port:φ6 Air port:φ4 1 Fuel : DME Combustion ratio : 11.6kW, Initial air ratio : 1.5
Experimental condition DME:99.9%,Methane:99%,Propane:99%
Experimental condition DME:99.9%,Methane:99%,Propane:99%
Experimental condition DME:99.9%,Methane:99%,Propane:99%
Combustion test at the atmospheric pressure (a) Diluted air temp.:300k (b) Diluted air temp.:700k Combustion rate:8kw,initial air ratio:1.5,pressure:0.1mpa
Experimental condition DME:99.9%,Methane:99%,Propane:99%
Combustion test at high pressure (a) Diluted air temp.:300k (b) Diluted air temp.:700k Combustion rate:8kw,initial air ratio:1.5,pressure:0.1mpa
reduction ratio reduction ratio at 0% O with EGR at 0% O without EGR The reduction of DME is successful by decreasing the oxygen concentration of combustion air under also high pressure.
reduction ratio reduction ratio at 0% O with EGR at 0% O without EGR The reduction of DME is successful by decreasing the oxygen concentration of combustion air under also high pressure.
com : generated in combustor accumulation by EGR Exhaust gas accu : by recirculation Total = Com accu Air Exhaust gas N Air DME DME accu n n1 k1 com k 100 nk Recirculat ed exhaust Exhaust gas gas
com : generated in combustor accumulation by EGR Exhaust gas accu : by recirculation Total = Com accu Air Exhaust gas N Air DME DME accu n n1 k1 com k 100 nk Recirculat ed exhaust Exhaust gas gas
com : generated in combustor accumulation by EGR Exhaust gas accu : by recirculation Total = Com accu Air Exhaust gas N Air DME DME accu n n1 k1 com k 100 nk Recirculat ed exhaust Exhaust gas gas
com : generated in combustor accumulation by EGR Exhaust gas accu : by recirculation Total = Com accu Air Exhaust gas N Air DME DME accu n n1 k1 com k 100 nk Recirculat ed exhaust Exhaust gas gas
concentration on actual EGR model generated in combustor by recirculation Combustion rate : 8kW Initial air ratio : 1.5 Diluted air temp : 300K Pressure : 0.1MPa High O % of combustion air Low Total emission is deceased with increasing EGR ratio.
Conclusion Under the atmospheric pressure DME combustion can be applied to the low oxygen concentration compared with methane and propane due to high burning velocity and low ignition temperature. The concentration becomes 6ppm. Under high pressure At 0.3MPa, the concentration is about twice as high as that at 0.1MPa. However, the concentration becomes under 11ppm by the low oxygen concentration of combustion air. Actual EGR model Total emission is decreased by EGR, although the emission by accumulation is increased. Because the emission by combustion is decreased sufficiently.
Thank you for listening
(at 0 %-O ), CO ppm 1 ton/h steam output boiler EGR Flow ratio Fuel Diluted Flue gas + Air Air rate 1% Diluted air of O recirculation Flow rate of air % Exhaust Combustor air O exhaust % gas O gas % Flue gas 10 100 80 60 40 0 Rated steam output 1 ton/h CO DME 11.35 Nm 3 /h 6.7 43.4 CO 10 ppm 0 0 10 0 30 40 50 FGR %
at 0% O Ex 0.1 0.1 O, Ex at 0% O 0.1 N, at0% O 0.79 Ex 0.1 N 0.79 O, Ex, Ex Fuel gas:dme, Combustion rate:8kw, Initial air ratio:1.5, Pressure:0.1MPa
emission by combustion Combustion rate : 8kW Initial air ratio : 1.5 Diluted air temp : 300K Pressure : 0.1MPa
emission by accumulation n=1 Air Fuel Fuel Air accu, n1 0 accu Exhaust gas n com, n1, accu, Chamber 100 O N CO HO n= n3 com, n1 com, n 100 100 n=3 n Exhaust gas accu, n1 n1 n 1のとき 0 n のとき accu n, k1 com, k 100 nk Results
O% of combustion air EGR ratio Flow rate of recirculation exhaust gas Flow rate of air 1% Diluted air O % Diluted air O % Exhaust gas O % Combustion rate : 8kW Initial air ratio : 1.5 Diluted air temp : 300K Pressure : 0.1MPa
O% of combustion air EGR ratio Flow rate of recirculation exhaust gas Flow rate of air 1% Diluted air O % Diluted air O % Exhaust gas O % Combustion rate : 8kW Initial air ratio : 1.5 Diluted air temp : 300K Pressure : 0.1MPa
Flow rate of Exhaust gas Combustion rate : 8kW Initial air ratio : 1.5 Diluted air temp : 300K Pressure : 0.1MPa
Momentum mass flux ratio - Velocity of diluted air m/sec Momentum mass flux Momentum mass flux ratio Fuel Air V V Fuel Air Diluted ait temp. DME Methane Propane 300K 700K 0.3 0. 0.1 Combustion rate : 8kW Initial air ratio : 1.5 Pressure : 0.1MPa 0 0 5 50 75 1001515017500 EGR ratio %
Velocity of diluted air m/sec Velocity of combustion air Diluted ait temp. DME Methane Propane 300K 700K 00 175 150 15 100 75 50 5 0 0 5 50 75 1001515017500 EGR ratio % Combustion rate : 8kW Initial air ratio : 1.5 Pressure : 0.1MPa