47 Development of a dual-fuel Precessing Jet nozzle to reduce NOx emissions, and increase radiant heat transfer in rotary kilns

Fields:

Aerodynamics, Laser Diagnostics, Combustion, Industrial Design

Supervisors:

Dr. Gus Nathan, Mr Steven Hill (FCT) and Dr Peter Mullinger

Moderator:

 

Number of Students:

2

Description:

Precessing Jet nozzles have been developed and applied to rotary cement and lime kilns firing natural gas and shown to reduce NOx emissions by 30-60%, while simultaneously increasing radiant heat transfer. The increased heat transfer can generate specific fuel savings and increased production rates, providing savings of up to US$1m per year. Despite these acknowledged benefits, many plants (especially in the USA) are not choosing to adopt this technology because of their requirement to be able to fire oil when natural gas is not available, notably during the winter months when the price of natural gas is high. To date a dual-fuel combustion system, to allow firing of either natural gas or oil, has not been developed.

The fundamental problem of a dual-fuel Gyro-Therm system is aerodynamic. Unlike in conventional burner systems, the oil lance cannot be at the centre of the Gyro-Therm burner. This causes the oil spray pattern to be asymmetric. The aim of the project therefore is to develop an aerodynamic solution to the problem by designing a suitable configuration to correct the asymmetry in the spray pattern.

The proposed project will continue from a 2001 project, so that all the equipment is available. A reduced scale configuration of the proposed burner design will be set up in the laser laboratory. Water will be used to simulate the oil spray, and air will be used in the same way as in full-scale designs. The laser sheet will be used assess the degree of asymmetry and to measure the size of the oil droplets. In this way modifications to the burner design will be developed and assessed to correct the asymmetry in the "oil" spray pattern. The project will be funded, and jointly supervised by, Fuel and Combustion Technology International (FCT). The project will be of interest to anyone interested in experimental fluid dynamics, in laser diagnostics and in the development of practical systems to reduce air pollution from industrial combustion systems. The project is best conducted by two people, since the rig must be operated by two people.