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Show • Lower Capital Equipment Costs -- Use of the ARCS in the design of a new system will require a smaller furnace volume and less downstream heat recovery equipment. • Reduced Pollutant Emissions -- The lower operating temperature of radiant burners reduces nitrogen oxide emissions while maintaining low levels of unburned hydrocarbons and CO. The first three benefits directly affect production costs that will be reflected in enduse prices. The cost benefits of radiant burner systems for pollutant emission control are also high, providing an indirect, but substantial reduction in the cost of production. These combined benefits can be realized by the wide variety of petrochemical and metals applications targeted for system development, thus improving their competitive position among international commodity suppliers. In addition, a substantial number of other high temperature processes such as glass production could benefit in future years. The ARCS project is being carried out in three phases. During the first phase, reformer and radiant burner modeling was performed to define system requirements and preliminary high temperature burner tests were completed. In Phase II, necessary burner and control system development tasks will be completed and a demonstration plant will be designed. In addition, major combustion system components will be fabricated and tested. During Phase ill, the ARCS will be installed and demonstrated at the field test site. HEATER MODELING AND DESIGN Thermal modeling specific to the steam reforming application was performed with the assistance of Kinetics Technology International, Inc. (KTI) of Monrovia, California. The modeling work was performed to determine required operating conditions for the ARCS radiant burners and to estimate heater construction costs. A recently completed design of a conventional top-fired reformer heater was selected as the baseline design for comparison with an ARCS heater of equivalent capacity. Detailed radiant section modeling was performed to determine burner operating conditions as a function of heater elevation necessary to achieve predetermined tube wall heat flux and temperature profiles. These flux and temperature profiles were determined from computer simulations of the chemical process correlated with performance data from conventional reformer units. Steam reforming is a highly endothermic and temperature dependent process. Since the process fluid temperature and rate of reaction both change as the reactants and products flow through the reformer, the amount of energy absorbed by the process varies significantly along the length of the process tubes. High temperature alloys currently used in reformer process tubes can be operated at temperatures of 1600° to 1700°F. To provide maximum conversion to hydrogen in a fixed process tube length, and a fixed furnace volume, it is desirable to supply sufficient energy to the process to raise the tube metal temperature to a selected design point along the 8 |
