(107c) Low-NOx Burner Retrofit Challenge

 AICHE 2016

Low-NOx Burner Retrofit Challenge

Craig Lieb
 Applications Engineer

Zeeco, Inc.

Prepared for Presentation at the 2016 Spring Meeting and 12th Global Congress on Process Safety

Houston, Texas -- April 10-14, 2016 (April 12, 2016)

Abstract

Recently, Zeeco accepted a retrofit challenge to replace 34 conventional burners at a European refinery with a capacity of 11.5 million tonnes per year. The project objectives were to significantly reduce NOx production, increase efficiency, and reduce coking and flame impingement on the heater process tubing. The 237.32 MMBtu/hr heater had a short radiant section and the existing burner flames were too long, creating hot spots on the roof process tubes, leading to tube coking. The required maximum flame dimensions were 9.6 feet (height) by 2.51 feet (wide) with a NOx guarantee of 40ppmv and CO guarantee of 40ppmv.

Due to the age of the customer’s forced draft preheated air ducting system, Zeeco proposed and performed a CFD study of the preheated forced air ducting system and radiant firebox to determine air flow distribution to the burners and the flame shape/dimension within the heater. After evaluating the study results, the customer performed ducting modifications and baffle plate installation. Zeeco determined the ZEECO® GLSF Round Flame Min-Emissions burner was the best choice to meet the flame geometry and burner placements required and still meet emissions targets. Zeeco also matched the existing heater mounting and air duct connection locations, which required Zeeco to design a customized burner geometry for this application. A multi-burner combustion test entailing two burner installations was conducted at Zeeco’s industrial-scale combustion test facility near Tulsa, Oklahoma, and then the project proceeded. This paper will detail the process, the lessons learned, and the outcomes of this successful retrofit project.