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Show PROCESS EQUIPMENT Both reforming processes would use a simple "cage type" reformer which would combine traditional reforming technology with cage type recuperator technology. Traditional reformers consist of a number of vertical tubes in a refractory lined vessel. The tubes are packed with a reforming catalyst and natural gas and steam/carbon dioxide are passed over the catalyst. The enclosure is heated by direct natural gas firing. Cage type recuperators commonly used in the fiberglass industry pass combustion air on the tube side and flue gas on the shell side to preheat the combustion air. The flow may be co-current, counter-current or both, depending on the flue gas temperature and the desired air preheat temperatures. The tubes are installed vertically. The hot flue gas enters at the bottom of the recuperator and exits from the top. The condensables in the flue gas, predominantly sodium sulfates, tend to run down the tubes and drop into a pit from which they are drained. These technologies can be combined by packing the recuperator tubes with catalyst and passing natural gas and steam or carbon dioxide through them. The tubes would still be installed vertically to allow free draining and reduce fouling. IV. B. GAS TURBINE CYCLE TEAM PROCESSES In this heat recovery scheme, the heat from the glass melter flue gas is used to generate shaft power or electricity using a Brayton cycle. Two processes are described in this section. In the first process, which implements this concept in its simplest form, all the heat input to the Brayton cycle is provided solely by heat exchange from the furnace flue gas. This yields approximately 300 KW for a 250 TPD glass production plant. In the second process, additional heat is provided through post-combustion downstream of the recuperator. This added heat input, along with recuperation of the heat from the gas turbine exhaust, helps yield approximately 1,600 KW of power in this case. PROCESS DESCRIPTION Small Gas Turbine Figure 5 depicts the process where the sensible heat in the glass melter flue gas is used to generate power without the use of supplemental post combustion. The glass melter flue gas exchanges heat with the air in the gas turbine cycle as it is cooled from approximately 2,200°F to 1,100°F. Heat from the flue gas is further recovered downstream of the recuperator through sequential heat exchange for natural gas, oxygen and cullet preheating. The cullet, preheated to around 550-600°F is fed to the melter along with the wet batch. The preheated natural gas is fired along with the preheated oxygen through specially designed oXY-fuel burners . . - 6 - |
