OCR Text |
Show Furnace support system systems include the following: Air System - A 1000 cfm blower running at 35" H20 provides main combustion air, which is controlled by a venturi meter connected to a flow computer and by a 6" actuated butterfly valve controlled by an automatic flow controller. Humidity of the incoming air is monitored by a hygrometer. Fuel System - This system includes a Maxon-provided standard gas train, pilot system and control panel to regulate gas pressure, provide flame safety supervision, and initiate automatic burner ignition. The natural gas is metered in the same way as the air system, with a venturi hooked up to a flow computer, and a control valve linked to a flow controller. Cooling System - Water from the furnace cooling pipes is circulated by a pump and cooled by a heat exchanger which is then cooled by an external chilled water source. Exhaust System - The stacks are exhausted by two exhaust hoods, which cool the hot exhaust by 5: 1 air dilution. The main exhaust blower moves air through the test cell at 15,000 cfm, with make-up air coming directly into the cell from outside via louvers and dormers. Emission Sampling System - Figure 3 is a schematic of the emissions sampling train. Samples are drawn by the extractive probe through ports in the center of the furnace stacks, 2' from the furnace and 2' from the stack exit. CO, C02, total hydrocarbons, O2, and NOx are measured. EXHAUST STACK STACK SAMPLING PORT WATER·COOLED SAMPLING PROBE EA TED SAMPLING HOSE REFRIGERA TION UNIT f[:[:] )=]11118 co & CO2 ~ . • ANALYZER HC &02 ANALYZER NOx ANALYZER Figure 3. Emissions Sampling and Analysis Train. Simulated Industrial Application The purpose of a thermal oxidizer is to destroy gaseous VOCs by raising the temperature of the VOC-Iaden air in a high-oxygen-content environment, causing oxidation to non-polluting substances. These VOCs are usually the by-products of industrial processes such as metallic |