PITA FY2014 Projects

Thermal Emissivities And Temperatures Of Tubes In Steam Methane Reformers

PI:Ed Levy, Mechanical Engineering and Mechanics

University:Lehigh University

Co-PI(s):Zheng Yao, Energy Research Center

Industry Affiliate(s):Air Products and Chemicals

Summary:Air Products and Chemicals is the world's largest producer of outsourced hydrogen to oil refineries, which use hydrogen to get the most out of every barrel of crude oil in making cleaner-burning transportation fuels. The hydrogen is produced using the Steam Methane Reforming (SMR) technology. The core of a typical SMR plant is the reformer where several hundred catalyst tubes are subject to high-temperature and high-pressure conditions close to the material limits of special alloys. The reformer tube temperature is perhaps the most critical parameter to ensure safe, reliable and efficient operation of SMR plants. Exceeding the tube design temperature by just 20°C will shorten the life expectancy of a tube by half. Moreover, overheating tubes can cause tube ruptures and plant shutdown. The total cost of a single such event can be several million dollars.

As thermal radiation is the dominant heat transfer mode inside the SMR furnace, reformer tube emissivity is an important physical parameter for accessing tube temperature via either models or radiation thermometry measurement. The surface emissivity not only depends on tube material properties such as composition, aging and surface roughness, but is also affected by operating condition including tube temperature, incident angle and wavelength. The typical reformer tube emissivity ranges from 0.8 to 0.9, and the corresponding difference between measured and actual tube temperature can be about 15°C, which is large enough to affect significantly the tube life or even to cause tube ruptures. This project will develop methodologies and data for obtaining accurate measurement of reformer tube emissivity and temperature.