Development of Low-NOx DME Multi-Port Burner

Abstract

This study focuses on the fundamental characteristics of DME (Dimethyl Ether) combustion, aiming at the development of low-NOx multi-port burner suitable for the tube-nested combustor. In the tube-nested combustion, the water tubes are moved into the furnace closely to the burner to cool the burning flame directly in the field of burning reaction leading to NOx reduction. To prevent the unburned combustibles emission, the diffusion burner used in the tube-nested combustor needs a high performance of the fuel-air mixing. Multi-port burner consists of a fuel-port and surrounding multi-airports , which induce a strong re-circulation flow. Thus the fuel-air mixing is enhanced so that the thermal NOx and CO emissions are significantly reduced. The NOx emission of the DME from the co-axial diffusion burner was over 130 ppm at 0% O 2. On the other hand, NOx emission of DME from the multi-port burner was reduced to 60 ppm at 0% O 2. With the help of the tube-nested combustion, NOx emission of DME was further reduced to 20 ppm at 0% O 2 .

B102 LOW NOx COMBUSTION OF DME BY EXHAUST GAS RECIRCULATION(Combustion-1)

“…Figure 2 All tire metallic parts of the setup consist of SUS304. [[he pressure of the combustion chamber is controlled by a pressure control valve, The multi-port diifision burner was designed by the authers to achieve well-mixed condition ef fuel gas, steady and strong re-circulation fo11owed by stable eombustion and small but uniformly distributed fiames [4], The fuel gas was issued from the eenter hole and the combustion air was from small multiple ports placed around the fuel p(nt. at 530mm frem the burner exit by using a water-cooled sampling probe, and were analyzed with the gas analyzer (Horiba Corp. PG-235a).…”

DME-Fired Water-Tube Boiler-A R&D Study

“…Then the flame should be small in size but uniformly distributed to prevent hot spots leading to thermal NOx generation. To meet such requirements, various types of burner plates were examined in the laboratory test (10) . The newly-developed burner plate, consisting of fuel injection port in the center and small air injection ports surrounding the fuel port, realized short and clearly distinguished flames aligned on a circumference, so that an annular flame with uniform height is formed.…”

“…This indicates that the proposed design principles for the burner plate are substantial for low-NOx combustion and may be applicable to the commercial-scale burner design. The detailed description can be found elsewhere (10) . In what follows, the 700 kW-class (steam output 1 ton/h) and 7 MW-class (10 ton/h) boilers are described.…”

Low NOx Combustion of DME by Means of Flue Gas Recirculation

“…The combustor, shown in Fig.3, consists of the multi-port diffusion burner and the combustion chamber. The multi-port diffusion burner was designed by the authors to achieve well-mixed condition of fuel gas, steady and strong re-circulation followed by stable combustion and small but uniformly distributed flames (4) . The fuel gas was issued from the center hole and the combustion air was from small multiple ports placed around the fuel port.…”