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Plants and Equipment
Published in Carl Bozzuto, Boiler Operator's Handbook, 2021
When the boiler feed water is colder than the steam and water in the boiler, it can extract more heat from the flue gas. Fluids colder than what is in the boiler can also be used in an economizer to recover the heat. An economizer on a high pressure boiler plant makes it as efficient as low pressure boilers. The feed water supplied to the economizer inlet is about the same temperature as steam and water in a low pressure boiler. It is important to be certain the feed water flows through the economizer in the opposite direction of the flue gas so that it sees hotter flue gas as it heats up and the coldest water is exposed to the gas just before it leaves the economizer. Economizers can heat feed water to a higher temperature than the flue gas leaving the economizer because of this counterflow arrangement. For the very large electric generating stations, the feed water is first heated by extraction steam from the steam turbine in the feed water train. It is then sent to the economizer at a temperature in the range of 450-490°F. In the economizer, the feed water temperature is increased to within 50°F of the boiling point at the pressure of the boiler. The feed water is then sent to the steam drum where it mixes with the water that is circulated in the boiler. A typical high pressure boiler would be boiling water at temperatures in the range of 650-690°F. The steam is separated from the circulating water in the steam drum. The dry steam is sent to a superheater, where its temperature is raised to more than 1000°F.
Steam Production and Cooling Tower Water Treatment
Published in Paul N. Cheremisinoff, Handbook of Water and Wastewater Treatment Technology, 2019
The main purpose of the steam drum in a water tube boiler is to provide sufficient volume and low enough velocity to allow separation of steam from water. This can be assisted significantly by the addition of mechanical devices within the drum, causing the steam to travel greater distances on its path to the outlet header. Such devices can greatly reduce the mechanical entrainment of water droplets in steam (mechanical carryover) but do not affect vaporous materials dissolved in steam (volatile carryover).
Boilers
Published in Béla G. Lipták, Optimization of Industrial Unit Processes, 2020
In a drum-type boiler, the water, through natural circulation in the boiler tubes, returns as a hot-water and steam mixture to the steam drum, while the solids accumulate in the mud drum. The steam leaves the steam drum, and fresh feed water is added to maintain the water reserve (level). Large, supercritical, once-through boilers do not use recirculation at full load.
The use of steam dryer with heat recovery to decrease the minimum exhaust flue gas temperature and increase the net efficiency of thermal power plant
Published in Drying Technology, 2023
Utility boilers are normally used in thermal power plants. The boiler model presented by Chantasiriwan[28] is illustrated in Figure 5. Components of utility boiler are furnace (F), evaporator (EV), steam drum (D), superheater (SH), reheater (RH), economizer (EC), and air heater (AH). Input parameters are mass flow rates of fuel and air (mf and ma), inlet air temperature (Tai), fuel temperature (Tf), fuel moisture content (xM), inlet feed water temperature (T9), main steam pressure (ps), reheat steam pressure (pr), cold reheat steam temperature (T2), mass fraction of reheat steam (yr), and surface areas of superheater, reheater, economizer, and air heater. Output parameters are mass flow rate of main steam (ms), main steam temperature (Ts), hot reheat steam temperature (Tr), and exhaust flue gas temperature (Tge). Surface areas of superheater and reheater are selected so that the boiler supplies main steam and reheat steam at specified mass flow rates and temperatures. In addition, the surface areas of economizer and air heater are determined for a specified value of Tge.
Investigation of Slagging Characteristics on Middle and low temperature heat transfers by Burning High Sodium and Iron coal
Published in Combustion Science and Technology, 2022
Bo Wei, Wenya Wu, Kunpeng Liu, Jianjiang Wang, Lijuan Chen, Jinrong Ma, Feng Wang, Xian Li, Wenjun Yang, Houzhang Tan
The slagging samples were collected in a 260 t/h MTS-CFBB along with flue gas flowing. A lot of heat transfers were arranged in the furnace of the boiler, as shown in Figure 1. The heated water was sent into low-temperature economizer by feed pump, and then flowed into the steam drum through high temperature economizer. The saturated water in steam drum was heated in water wall, meanwhile, the saturated steam was flowed through stage 1 evaporator, stage 2 evaporator, stage 1 superheater, stage 2 superheater, and stage 3 superheater in sequence, at last, the superheated steam was used into steam turbine or heat supplying. After the boiler had been operating about 30 days, the slagging samples was collected at stage 1 evaporator (Sampling point A), stage 3 superheater (Sampling point B), stage 2 superheater (Sampling point C), and stage 2 evaporator (Sampling point D) as also shown in Figure 1 when the boiler shut down. From the boiler design information, when the boiler smooth operation at full capacity, the gas temperature range of stage 1 evaporator, the stage 3 superheater, the stage 1 superheater, and the stage 2 evaporator was 876°C–844°C, 844°C–780°C, 720°C–609°C, and 609°C–539°C, respectively.
An investigation of the cooling, heating and power systems integration with carbon capture and storage for LNG carriers
Published in Ships and Offshore Structures, 2023
In the WHR system, the process water coming from the TC air cooler passes through the economiser and evapourator of the exhaust gas boiler (EGB), is collected in the steam drum, superheated, and enters the steam turbine (ST), respectively, as shown in Figure 2. The steam from the turbine is then condensed and collected to the feed water tank. The process water in this tank is recycled to the system with a pump. Seawater is used for condensing steam.