Boiler Feed Application Pumps are a special type of pump used to pump water into a steam boiler. Water can be a newly supplied or returned condensate produced by the condensation of steam produced by the boiler. These pumps are usually high-pressure units that draw from the condensate return system and can be centrifugal or positive displacement. Feedwater pumps range in size up to many kilowatts and the motor is typically separated from the pump body by some style of mechanical coupling.
Large industrial condensate pumps may also serve as feedwater pumps. In order to force the water into the boiler, the pump must definitely generate enough pressure to overcome the steam pressure developed by the boiler. This is typically achieved through the employment of a pump. Another common form of feed pump runs constantly and is given a minimum flow device to prevent over-pressuring the pump on low flows
In thermal power plants, the boiler feedwater pump (BFP) is one of the key auxiliary machines that represent the guts of the system. BFP has been improved and developed with the increasing capacity of thermal power plants, improvements to accommodate higher temperatures and pressures, and changes in operating methods. This white paper describes how BFP has been scaled up to handle higher pressures’ Key Specifications.
Typical BFP structures and materials for conventional supercritical and combined-cycle power plants. Shaft seal and bearing characteristics; technological development for higher capacity and performance. Actual development and provision of BFP with 100% capacity.
Improved structural design to increase the stress tolerance of the BFP to accommodate the more stringent conditions of thermal power plant operation associated with renewable energy diffusion. An example of an effort to streamline BFP design to reduce manufacturing costs and save space.
In terms of capacity and pressure, BFP has expanded and matured with the increase in thermal power generation facilities. Among the pumps used in thermal power plants, the BFP consumes the most energy because it has to generate the high pressure required by the boiler. This means that improving the efficiency of BFP is an important issue that needs to be resolved to reduce its impact on the environment.
The impeller used in BFP is a centrifugal pump with a specific speed (Ns) of about 120 to 250 (m3 / min, m, min1). In general, the higher the specific speed within this range, the higher the pump efficiency, and the same the specific speed, the higher the flow rate. Two BFPs, each with a capacity of 50%, are typically used as the main feed pump. If BFP can provide 100% capacity, not only will it increase capacity to increase specific speed, but it will also improve efficiency by saving space and resources
In recent years, the introduction of renewable energy such as solar power and wind power has been progressing. Renewable energy does not use fossil fuels and does not emit carbon dioxide during power generation, so it is expected to continue to spread as one of the measures against global warming. However, since the output from solar power and wind power greatly depends on the weather conditions such as weather and wind, there is a disadvantage that it is difficult to operate an electric energy system using renewable energy in a stable manner.
To address this issue, thermal power plants need to provide increasingly flexible network operations with higher capacity to adapt to supply and demand. In particular, it is required to improve the load factor, minimize the minimum load factor, and shorten the start-up time.
In association with the supply-and-demand adjustment capability added to thermal power plants, BFPs must operate under more severe conditions such as increased frequency of start-ups and shutdowns, changes in feedwater temperature, and increased frequency of downhills. To meet these requirements, efforts have been made to improve the stress tolerance (toughness) of BFPs by examining the structure, materials, and design.
As described earlier, BFPs are the center of most piping systems in thermal power systems and thus are needed to supply high levels of practicality and reliability. On the other hand, it is also important to provide electricity at the lowest possible price, especially in developing countries, where demand for electricity is increasing and therefore the construction of many new thermal power plants is planned.
For this reason, pump suppliers needed to get together to change the instrumentation for power generation plants and build efforts to cut back the prices for such equipment.