China
Africa
Explore chapters and articles related to this topic
Combustion Gas Turbines
Published in Neil Petchers, Combined Heating, Cooling & Power Handbook: Technologies & Applications, 2020
Exhaust losses include the pressure drop through the exhaust stack, silencers, and any heat recovery equipment that creates a back-pressure on the turbine. Back-pressure reduces the pressure ratio across the turbine wheels and, therefore, the power output of the turbine. The turbine will lose approximately 0.25% of power per in. H2O (0.187cm Hg) back-pressure. Heat rate will also increase by about the same percentage.
Plant Security
Published in Frank R. Spellman, Fundamentals of Public Utilities Management, 2020
Backflow may occur under two types of conditions: backpressure and backsiphonage. Backpressure is the reverse from normal flow direction within a piping system that is the result of the downstream pressure being higher than the supply pressure. These reductions in the supply pressure occur whenever the amount of water being used exceeds the amount of water supplied, such as during water line flushing, firefighting, or breaks in water mains. Backsiphonage is the reverse from normal flow direction within a piping system that is caused by negative pressure in the supply piping (i.e., the reversal of normal flow in a system caused by a vacuum or partial vacuum within the water supply piping). Backsiphonage can occur where there is a high velocity in a pipeline; when there is a line repair or break that is lower than a service point; or when there is lowered main pressure due to high water withdrawal rate, such as during firefighting or water main flushing.
Process Design Considerations for Large–Scale Chromatography of Biomolecules
Published in Kenneth E. Avis, Vincent L. Wu, Biotechnology and Biopharmaceutical Manufacturing, Processing, and Preservation, 2020
Richard Wisniewski, Egisto Boschetti, Alois Jungbauer
The pump configuration must ensure complete drainage (e.g., a vertical flow path should be selected). A lobe pump with a flowmeter may provide adequate solution for certain applications where the system back pressure is moderate. Depending on the pump size and the required range of flow rate control, the back pressure range may extend from 50 to 300 psi (3.3–20 bar). The flow rate range cannot be too wide since only the motor speed control can be used for flow control. Low flow rates may be obtained by combining the flowmeter with a bypass or throttling valve to recirculate liquid externally or internally (due to slip backflow) within the pump. Such solutions make the system complex and more costly, complicate the cleaning cycle and may cause the pump to run less efficiently (this factor may also add extra energy to the fluid, causing a temperature increase). In practice, backslip flow in the lobe pump is much more pronounced in small pumps than in larger ones. At higher back pressures, small pumps may produce very little actual flow. Due to backslip flow, the controllable flow range rapidly decreases with an increase in back pressure. In such cases, the diaphragm pump is a better choice, since it performs well at higher back pressures.
Performance evaluation of a combined cycle power plant integrated with organic Rankine cycle and absorption refrigeration system
Published in Cogent Engineering, 2018
I.H. Njoku, C.O.C. Oko, J.C. Ofodu
For combined cycle power plant operating with air cooled condenser, ambient air conditions has direct impact on the performance of the gas turbine cycle and the steam turbine cycle respectively. A drawback of air-cooled condensers (ACC) is that their performance can decline as ambient temperatures increase and result in loss of steam turbine power output. Increased ambient temperature reduces the heat transfer (heat rejection) rate during steam condensation leading to rise in turbine back pressure. As the turbine back pressure increases, the output of the steam turbine decreases (Ramani, Rupeshkumar, Amitesh Paul, Anjana, & Saparia, 2011). Since air cooled condensers operate with the ambient dry bulb temperature as the theoretical minimum attainable temperature, their efficiency can drop by about 10% when ambient temperatures rise (Gadhamshetty, Nirmalakhandan, Myint, & Ricketts, 2006; Nirmalakhandan, Gadhamshetty, & Mummaneni, 2008).