Waste Heat Recovery System Market to be worth USD 65.87 Billion by 2021: know about the factors driving the market
The steam & electricity generation application segment is dominated by Waste Heat Recovery System Market. The market in application is also expected to witness growth between 2016 and 2021 owing to growing demand for energy in North America, Europe, and Asia-Pacific. The growing construction industry in the Middle East and Asia-Pacific countries such as China, Japan, and India also drive the market in this segment.
The WHRS market is classified based on end-use industry into petroleum refining, metal production, cement, chemical, paper & pulp, and others. The market is dominated by the petroleum refining end-use industry. In this industry, WHRS is used for various processes such as distillation, thermal cracking, catalytic, and treatment. Cement is the fastest-growing end-use industry of WHRS. The most energy-intensive process in the cement industry is clinker production in kilns. The applications of the waste heat recovered from stack exhausts, combustion exhaust gases, and other sources include preheating and power generation.
Currently, Europe is the largest WHR system market, in terms of value, closely followed by North America. North America is expected to witness a moderate growth rate. Some of the factors driving the North American market are stringent government regulation regarding energy saving and energy efficiency, and incentives provided by the governments, including tax rebates. The region is characterized with continuous technological innovations in the WHR industry and presence of some of the major players in the region.
Heat Recovery Steam Generator Design
Heat recovery steam generators (HRSGs) are used in power generation to recover heat from hot flue gases (500-600 °C), usually originating from a gas turbine or diesel engine. The HRSG consists of the same heat transfer surfaces as other boilers, except for the furnace. Since no fuel is combusted in a HRSG, the HRSG have convention based evaporator surfaces, where water evaporates into steam. A HRSG can have a horizontal or vertical layout, depending on the available space. When designing a HRSG, the following issues should be considered:
The pinch-point of the evaporator and the approach temperature of the economizer
The pressure drop of the flue gas side of the boiler
Optimization of the heating surfaces
The pinch-point (the smallest temperature difference between the two streams in a system of heat exchangers) is found in the evaporator, and is usually 6-10 °C, which can be seen in Figure 2. To maximize the steam power of the boiler, the pinch-point must be chosen as small as possible. The approach temperature is the temperature difference of the input temperature in the evaporator and the output of the economizer. This is often 0-5 °C. The pressure
Drop (usually 25-40 mbar) of the flue gas side also has an effect on the efficiency of power plant. The heat transfer of the HRSG is primarily convective. The flow velocity of the flue gas has an influence on the heat transfer coefficient. The evaporator of heat recovery boiler can be of natural or forced circulation type. The heat exchanger type of the evaporator can be any of parallel-flow, counter-flow or cross-flow. In parallel-flow arrangement the hot and cold fluids move in the same direction and in counter-flow heat exchanger fluids move in opposite direction.