Heat switch gaseous

Fuel switch. The choice of fuel used in furnaces and steam boilers has a major effect on the gaseous utility waste from products of combustion. For example, a switch from coal to natural gas in a steam boiler can lead to a reduction in carbon dioxide emissions of typically 40 percent for the same heat released. This results from the lower carbon content of natural gas. In addition, it is likely that a switch from coal to natural gas also will lead to a considerable reduction in both SO, and NO, emissions, as we shall discuss later. 

According to Grignard, the chlorination must commence in the gaseous phase, and so the methyl chloroformate is first heated in such a way as to produce a slight pressure, then the lamps switched on and the chlorine then introduced at such a rate as to prevent the reaction from being violent. The product may be rectified as described in the preceding method. 

These burners are used where the customer may need to switch between a gaseous fuel like natural gas and a liquid fuel like oil, usually for economic reasons. These burners normally operate on one fuel or the other, and occasionally on both fuels simultaneously. Another application where multiple fuels may be used is in waste incineration. One method of disposing of waste liquids contaminated with hydrocarbons is to combust them by direct injection through a burner. The waste liquids are fed through the burner that is powered by a traditional fuel such as natural gas or oil. The waste liquids often have very low heating values and are difficult to combust without auxiliary fuel. This further complicates the burner design where the waste liquid must be vaporized and combusted concurrently with the normal fuel used in the burner. 

Several modem processes for the production of carbon-based blacks (flame carbons . v.) are based on the thermal decomposition of lower gaseous hydrocarbons in the absence of air. Developed in the 1930s, the thermal black process is still used for the production of pigments. In distinction from other carbon black processes, the method is discontinuous the reaction furnace is heated to about 1400°C with a mixture of natural gas and air, then the air is switched off. The gas is decomposed, an andothermic process which cools the furnace. This cycle is then repeated. Fine thermal blacks of particle size 120-200 nm and medium thermal blacks of 300-500mn are typically produced (Buxbaum, 1998). 

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