OCR Text |
Show SPRAY OIL MIXER Figure 1: The Multiple Venturi Atomizer INTRODUCTION Heavy residual oil is the fuel of choice for industrial and utility boiler owners where natural gas and coal are not continuously available. Many regions within the United States have been designated as Ozone Non-Attainment areas under the recently revised National Ambient Air Quality Standards ( N A A Q S ) and are under increasing pressure to reduce N O x emissions. N O x emissions reductions can be obtained by (1) switching to an alternate fuel with less propensity for N O x production such as natural gas, (2) installation of flue gas treatment systems such as S C R and S N C R , and (3) installation of low N O x burner equipment. The first option is not possible where natural gas is unavailable, such as in the Northeast United States. The second option, S CR or S N C R , is costly and prohibitive to many industrial boiler owners. The most cost effective option to reduce N O x emissions from residual oil is the installation of low N O x burner equipment. This paper compares the results of two recent applications where low N Ox techniques are utilized in a field-erected and a package water tube boiler. Multiple Venturi MV Atomizer: COEN's predominant atomizer of choice for boiler applications is the Multiple Venturi ( M V ) atomizer. The M V atomizer is an inside mix, twin fluid atomizer used for the combustion of liquid fuels from light oil up to heavy asphalt or pitch which require heating prior to atomization (see Figure 1). Liquid fuel passes through the central fuel tube, surrounded by the steam tube, until reaching the multiple venturi mixer where a two-phase mixture is produced. This mixture is forced through a nozzle body to increase its momentum prior to exiting through a plain-jet cap. The cap design of the M V allows great flexibility for flame shaping through the cap drilling pattern. Four different sizes of the M V atomizer are used to achieve capacity ranges from 1 to 40 gallons per minute fuel flow. BACKGROUND N O x is the term typically used to refer to N O , and N O 2 formed by combustion. Man-made N O x sources are a small portion of the global N O x ; however, they tend to be concentrated in urban areas resulting in excessive production of ozone which is a known lung irritant. The |