Supercritical carbon dioxide is a fluid state where carbon dioxide is operated above its critical point which causes the compound to behave as both a gas and a liquid simultaneously with the unique ability to flow as a gas though at the same time dissolve materials like a liquid. SCO2 changes density over small difference in temperature or pressure, though stay in the same phase; allowing large amount of energy to be extracted at higher temperatures.
Inherent in its name, the BFPT must be fully compatible with the boiler feed pump. In other words, the necessary power and speed of the BFPT are determined by the requirements of the pump. In a fully integrated and dynamic system such as this, a large portion of the design requires developing a proper heat balance that will optimize the plant performance. In general, the boiler feed pump turbine uses both steam from the boiler and the main turbine to drive the mechanical shaft connected to the boiler feed pump. This arrangement has proven highly successful in efficiently applying the steam’s thermal energy throughout the plant. In certain arrangements, the BFPT can instead accept steam from cold reheat lines, main unit crossover piping lines, and different extractions from the main turbine. Regardless of the source, one distinction specifically unique to the BFPT is that it must accept steam from two separate sources.
It is also important to note that about 20-25% of the total heat generated is used for producing brake power (useful work). The cooling system should be designed to remove 30-35% of total heat and the remaining heat is lost in friction and carried away by exhaust gases.
Geothermal energy has become more and more popular globally due to its sustainability and economic stand point. Geothermal power plants run on a variety of temperatures and utilize hydrothermal resources (water/steam and heat) from below the earth surface to generate electricity for people’s daily consumption. Resources can come from dry steam or hot water wells.
There are three kinds of Geothermal cycle for power plants: binary cycle, dry steam and flash steam. Binary cycle power plants use the heat transfer from geothermal hot water to secondary fluids with a low boiling point at the lower end of standard geothermal temperature (225 to 360 F). This heat will cause the secondary fluid to bubble and turn into steam in the heat exchanger, which is then used to turn the turbine. Since water and secondary fluids are kept apart in the cycle, air emission is minimized.
The useful mechanical energy converted from this system is generally used to drive a centrifugal compressor positioned on the opposite end of the shaft. In the case of this expander-compressor setup, the mentioned turboexpander technology avoids the excessive use of fuel consumption seen in other systems, and significantly decreases the CO2 footprint of the overall design. As well, there are various examples of turboexpanders that use an expander-generator setup, which converts the mechanical energy from the turbine into direct electrical power. Turboexpanders have come a long way in the last 40 years. With the advent of magnetic bearings and more advanced sealing systems, turboexpanders have been able to handle shaft speeds in large and small machines of up to 10,000 rpm and 120,000 rpm, respectively. Moreover, innovations in specific CFD modules for turbomachinery have allowed turboexpander systems to achieve efficiencies upwards of 90%.
Though the expansion of steam takes place in the nozzles and blades, the influence of the leakage steam during the startup phase is significant with steam expanding through the labyrinths resulting in expansions, condensation, and increased velocities which may even reach supersonic levels. During cold start, the flow is minimal, the temperature of the metal is at room temperature and heat exchange happens between the steam and metal parts resulting in thermal stress.
Many people speculate about the confusion on what is considered a compressor, a blower, or simply a fan. In essence, each of these turbo-machines achieve a pressure rise by adding velocity to a continuous flow of fluid. The distinctions between fans, blowers, and compressors are quite simply defined by one parameter, the specific pressure ratio. Each machine type, however, utilizes a number of different design techniques specific to lower and higher-pressure applications. As per the American Society of Mechanical Engineers (ASME), the specific pressure is defined as the ratio of the discharge pressure over the suction pressure (or inlet pressure). The table shown below defines the range at which fans, blowers, and compressors are categorized.
Similarities between the design of fans and blowers occur near the lower end of a blower’s range. As well, many design parallels exist between high-pressure blowers and compressors. For the article, we will be investigating the different design characteristics of centrifugal blowers. Blower selection depends on a number of factors including operating range, efficiency, space limitations, and material handled. Figure 1 shows a number of different impeller blade designs that are available for centrifugal blowers.
In recent years, more and more applications of FSI are found in the reliability research of turbomachinery. Most of them are about turbines, and a few of them address pumps. Kato  predicted the noise from a multi-stage centrifugal pump using one-way coupling method. This practical approach treats the fluid physics and the solid physics consecutively.
Geothermal energy is categorized as a “green energy”, with low emission of approximately 5% of carbon dioxide, 1% H2S, 1% sulfur dioxide and less than 1% of the nitrous oxide of an equal sized fossil or coal power plant. Concentrations of each environmentally disruptive gases are controlled by temperature, composition of fluid, and geological setting. Although most of the geothermal emissions commonly come from existing geothermal resource gas, some percentage of the emission also comes from various processes of the energy conversion process. Non-condensable gases are also emitted as a part of high temperature process of geothermal energy conversion.
According to various studies, the type of geothermal power plant design would really impact the production rate of the mentioned gasses. The selection between open-loop and closed (binary)-loop system is essential while taking into consideration air emission. Geothermal plants to this date are commonly separated into three main cycle design: dry-steam, flash-steam or binary –the first two extensively generate more greenhouse gasses (GHGs) compared to the last. In a binary loop system, gases which are removed from the system will not be transferred to the open atmosphere, instead, after transferring the heat gasses will be run through back to the ground, and result in minimal air pollution. In contrary, open-loop system emits all of the emission gas contained such as hydrogen sulfide, carbon dioxide and many more. There are also different factors which cause the technology to emits gases that are naturally present in the fluid such as fluid chemistry/composition, fluid phase, and geological setting to temperature.
Some of the factors that may cause excitation of a natural frequency include rotational balance, impeller exit pressure pulsations, and gear couplings misalignment. The effect of the resonance can be determined by evaluating the pumping machinery construction. All aspects of the installation such as the discharge head, mounting structure, piping and drive system will affect lateral, torsional and structural frequencies of the pumping system. It is advised that the analysis be conducted during the initial design phase to reduce the probability of reliability problems and the time and expense associated.