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Proper Steam Bypass System Design Avoids Steam Turbine Overheating
The steam bypass system is generally used during the following modes of operation: start-up and shutdown, steam turbine trip, steam turbine no-load or low-load operation, and simple-cycle operation. On start-up, the isolation of the CTG/HRSG from the STG allows the CTG to be placed on load without delay and well before the heat-up and roll-off of the STG. In addition, a faster start-up of the STG is possible since the bypass system provides the capability of close temperature matching between the steam inlet temperature and the steam turbine metal temperature.
Revision Date: 9/9/2019
Tags: 221118 - Other Electric Power , 221118 - Other Electric Power , Turbine, Valve, Power Engineering
Membrane to condense water and recover heat from flue gas
NETL has partnered with Gas Technology Institute (GTI) and Media & Process Technology Inc. (MPT) who have developed a nanoporous ceramic membrane device that condenses water and recovers heat from flue gas.
Revision Date: 4/30/2019
Tags: 221118 - Other Electric Power , 221112 - Fossil Fuel 化石燃料, Media & Process Technology, Inc., Membrane, Heat Recovery, Power Engineering
How vinyl ester linings can help defend against aggressive conditions experienced in FGD processes.
This is a white paper by Hempel which is available through the Power Engineering site. McIlvaine has been following the use of these linings as opposed to metal alloys or FRP. They have been popular in China.
Revision Date: 12/13/2018
Tags: 221112 - Fossil Fuel 化石燃料, Hempel Americas, Lining, Power Engineering
Maintaining High Combined Cycle HRSG Efficiency and Reliability
This article in Power Engineering by Brad Buecker of Kiewit addresses chemical treatment of HRSG feedwater. During the heyday of coal-fired power plant construction and operation in the last century, many lessons were learned regarding correct water/steam chemistry control in high-pressure, fossil-fuel steam generators. Even seemingly minor issues had the potential to cause serious problems, and some corrosion-induced failures led to injuries and death of plant personnel. Progress in transferring these lessons to the combined cycle power industry has often been slow, and a number of outdated chemistry concepts continue to appear in the specifications for new combined cycle plants. Some problems are magnified by the unique geometrical features of heat recovery steam generators (HRSGs) as compared to their coal unit counterparts. This article will examine three of the most important issues in this regard, as outlined below: • Unless the condensate/feedwater system of the HRSG contains copper alloys (very rare), an oxygen scavenger should not be part of the chemical treatment program. Use of oxygen scavengers, a more accurate term is reducing agent, induces flow-accelerated corrosion (FAC) of plain carbon steel. FAC has caused catastrophic piping and tube failures at a number of facilities over the last three decades, and it continues to occur at many plants. • Tri-sodium phosphate has served as the primary chemical for boiler water treatment in many base-loaded coal units, and the chemistry is often employed in HRSGs. Even at steady load, phosphate treatment is problematic due to the phenomenon known as phosphate hideout. In cycling units, hideout may make phosphate chemistry extremely difficult to control. • While a strong focus should always be placed on operating chemistry, off-line chemistry control is frequently neglected. Air in-leakage into water-filled steam generator networks during down times can significantly damage tubes, piping, turbine blades and rotors, and other equipment. Given the regular cycling nature of most power plants in today's environment, the potential for air ingress and subsequent corrosion may be extensive.
Revision Date: 3/5/2018
Tags: Kiewit, Feedwater, Chemical, Heat Recovery Steam Generator, Power Engineering
Dry scrubber options as listed by Kiewit
In addition to Graff-Wulff, Babcock Turbosorp, and Allied/Lurgi design provide the CFB options. SDA is more widely used but concern about atomizer O &M costs as well as distributing the slurry in droplets which will dry prior to reaching the particulate collector.
Revision Date: 3/26/2014
Tags: Kiewit Power Engineers, Power Engineering
Controlling Water Usage and Wastewater Discharge
This article discusses ways to reduce power plant water consumption and the volume of wastewater discharged. In particular, the author says that clarification and softening of cooling tower make-up water will lead to fewer cooling tower blowdowns and improve water conservation. The article also discusses a wastewater recovery and reuse system which includes micro- or ultra-filters, an ion exchanger and a reverse osmosis system. For zero liquid discharge, an evaporator/crystallizer would also be required.
Revision Date: 11/10/2011
Tags: 221112 - Fossil Fuel 化石燃料, Xylem, Clarifier, Reverse Osmosis, Ion Exchange, Evaporator, Membrane, Cooling Water, Wastewater Treatment, Water Reuse, Zero Liquid Discharge, Power Engineering