Energy efficiency reducing

Microwave heating differs from conventional heating in several respects. First, energy is only transferred directly to those reaction components that are susceptible to microwave polarization. This may improve energy efficiency, reducing the need to heat vessels or the heating apparatus itself it may allow energy to be directed into specific parts of the reactive system such as metal particles,18 or susceptible solid supports.19,20 In some cases, this reduces or eliminates the need for solvents, with obvious economic and environmental benefits.21 A second consequence of this... 

Source reduction, inprocess recycling, and improved energy efficiency reduce the amounts of raw materials and energy required. 

The rapid heat transfer allows nearly isothermal operation with a defined residence time. Therefore, undesired side reactions can be effectively suppressed. The formation of hot spots within the reactor and reactor runaway during fast, highly exothermic reactions can be avoided. As a consequence, higher operating temperatures are attainable, and the same conversion can be achieved with a smaller reactor volume and less catalyst. The smaller unit size in turn improves the energy efficiency, reducing the operational cost. 

Energy efficiency of the process. If the process requires a furnace or steam boiler to provide a hot utility, then any excessive use of the hot utility will produce excessive utility waste through excessive generation of CO2, NO, SO, particulates, etc. Improved heat recovery will reduce the overall demand for utilities and hence reduce utility waste. 

Cooling tower blowdown can be reduced by improving the energy efficiency of processes, thus reducing the thermal load on cooling towers. Alternatively, cooling water systems can be switched to air coolers, which eliminates the problem altogether. 

Reducing products of combustion from furnaces, steam boilers, and gas turbines by making the process more energy efficient through improved heat recovery. 

Increased energy efficiency. Increasing energy efficiency and the introduction of cogeneration reduce CO2 emissions. Remember that emissions should be viewed on a global basis, as discussed in Chap. 10. 

During the late 1970s, concerns were raised about levels of airborne formaldehyde in buildings resulting primarily from constmction using composite panels bonded with urea—formaldehyde resins and combined with energy-efficient building practices which reduced air losses. 

The second law can also suggest appropriate corrective action. Eor example, in combustion, preheating the air or firing at high pressure in a gas turbine, as is done for an ethylene (qv) cracking furnace, improves energy efficiency by reducing the lost work of combustion (Eig. 4). 

Mechanical losses - Bearings, lip seals, mechanical seals, packings, etc., all consume energy and reduce the pump s efficiency. Small pumps (less than 15 HP) are particularly susceptible. 

Flue gas recirculation (FGR) is the rerouting of some of the flue gases back to the furnace. By using the flue gas from the economizer outlet, both the furnace air temperature and the furnace oxygen concentration can be reduced. However, in retrofits FGR can be very expensive. Flue gas recirculation is typically applied to oil- and gas-fired boilers and reduces NO, emissions by 20 to 50%. Modifications to the boiler in the form of ducting and an energy efficiency loss due to the power requirements of the recirculation fans can make the cost of this option higher. 

Use energy-efficient measures such as waste heat recovery from process gases to reduce fuel usage and associated emissions. 

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