Design Considerations and Operation of Condenser Bypass Systems in Combined Cycle Power Plants: Part 2

2004 ◽  
Author(s):  
Richard H. Eaton ◽  
Edward R. Blessman ◽  
Kevin G. Schoonover
Keyword(s):  
Power Plants ◽  
High Energy ◽  
Combined Cycle ◽  
Condenser Tube ◽  
Design Considerations ◽  
Number Of Factors ◽  
Combined Cycle Plant ◽  
Compact Design ◽  
Functional Operation ◽  
Design Challenges

Premature condenser tube failures in combined cycle power plants have been experienced at several installations related to fatigue and erosion of the condenser tubes. The admission of high energy steam into the condenser poses design challenges with respect to the compact design of the condenser in the combined cycle power plant. Dissipation of energy within the condenser is a specialty design usually performed by the condenser manufacturer. Part 1 of this paper reviews condenser design and plant operation that impacts, or may contribute to, condenser tube failures. Part 2 of this paper reviews the condenser bypass system, identifies related opportunities, and provides design considerations to optimize condenser reliability through the controlled admission of high energy steam into the condenser. A number of factors go into properly designing sub-systems, as required by the functional operation of the combined cycle plant. The bypass system is one sub-system, considered integral with the condenser.

Design Considerations and Operation of Condenser Bypass Systems in Combined Cycle Power Plants: Part 1

2004 ◽  
Author(s):  
Richard H. Eaton ◽  
Edward R. Blessman ◽  
Kevin G. Schoonover
Keyword(s):  
Power Plants ◽  
High Energy ◽  
Combined Cycle ◽  
Design Considerations ◽  
Turbine Condenser ◽  
Wide Range ◽  
Combined Cycle Plant ◽  
Steam Turbine Condenser ◽  
Functional Operation ◽  
And Control

As many Combined Cycle Power Plants have come into operation over the last 10 years, premature condenser tube failures have been experienced at several installations. This paper reviews factors and mechanisms contributing to such failures. The steam turbine condenser must operate under a demanding, wide range of conditions. Tubes within the condenser experience cyclic stresses, direct contact from admission of high-energy steam into the condenser, and the effects from a wide service range beginning with start-up and commissioning through continuous or intermittent daily operation. A number of factors go into properly designing condenser related sub-systems as required by the functional operation of the combined cycle plant. The condenser bypass system is a critical component directly affecting the operation, maintenance and control of conditions experienced by the condenser. Part 1 of this paper identifies related problems experienced, in the field, within the condenser considering operation and maintenance, and also provides design considerations to avoid occurrence of tube failures. Part 2 of this paper addresses many key points for consideration with respect to the design and implementation of the high-energy bypass system leading into the condenser.

scholarly journals Ruhrchemie/Ruhrkohle’s Technical Version of the Texaco Coal Gasifier as Part of a Combined Cycle Plant

1982 ◽  
Author(s):  
B. Cornils ◽  
J. Hibbel ◽  
P. Ruprecht ◽  
R. Dürrfeld ◽  
J. Langhoff
Keyword(s):  
High Pressure ◽  
Power Plants ◽  
Coal Gasification ◽  
Operating Time ◽  
Combined Cycle ◽  
Gas Generation ◽  
Load Following ◽  
Gasification Process ◽  
Steady State Operation ◽  
Combined Cycle Plant

The Ruhrchemie/Ruhrkohle variant of the Texaco Coal Gasification Process (TCGP) has been on stream since 1978. As the first demonstration plant of the “second generation” it has confirmed the advantages of the simultaneous gasification of coal: at higher temperatures; under elevated pressures; using finely divided coal; feeding the coal as a slurry in water. The operating time so far totals 9000 hrs. More than 50,000 tons of coal have been converted to syn gas with a typical composition of 55 percent CO, 33 percent H2, 11 percent CO2 and 0.01 percent of methane. The advantages of the process — low environmental impact, additional high pressure steam production, gas generation at high pressure levels, steady state operation, relatively low investment costs, rapid and reliable turn-down and load-following characteristics — make such entrained-bed coal gasification processes highly suitable for power generation, especially as the first step of combined cycle power plants.

scholarly journals Root Cause Analysis of Outages in Combined-Cycle Power Plants

1984 ◽  
Author(s):  
R. L. Duncan ◽  
H. W. Brown
Keyword(s):  
Control System ◽  
Data Base ◽  
Power Plants ◽  
Combined Cycle ◽  
System Failures ◽  
Root Cause ◽  
Combined Cycle Plant ◽  
Equipment Failures ◽  
Plant Equipment ◽  
Insight Into

A data base system has been developed to analyze root causes of failures and unplanned outages in combined-cycle power plants and related equipments. Raw data in the form of plant work orders and outage reports are provided by thirteen utilities. Data encompasses both scheduled and unscheduled maintenance activities involving all plant equipments of mostly combined cycle installations. Primary objectives are to evaluate combined-cycle plant maintenance records to determine root causes of equipment failures, to analyze maintenance data to identify key areas for reliability, availability, and maintainability (RAM) improvement, and to develop an automated data processing system for feedback to project participants. ERAS (EPRI Reliability Assessment System) data were analyzed to determine failure rates and mean downtimes of critical equipment used in combined-cycle plants and integrated gasification combined-cycle plants of the future. A primary ERAS data requirement is to document plant equipment failures involving planned outages, unplanned outages, and noncurtailing maintenance. Maintenance data are mailed directly from the plant on a monthly or weekly basis. In order to maintain significant coordination and feedback, documentation is also mailed by ARINC Research to manufacturers and EPRI project personnel. ERAS is foremost a repository, based on dBASE II software, of raw data records which address combined-cycle plant equipment scheduled and unscheduled maintenance activity. By using dBASE II commands, data contained in “DAILY”, “MONTHLY”, “PROBLEMS”, and “FIREHRS” data base files (DBFs) are analyzed in many ways. Data may be separated by manufacturer or utility. RAM statistics may be analyzed according to six data hierarchies, grouping data by common plant design, system, subsystem, or components. Special report forms can be developed depending on specific data processing needs. During 1982 a total of 1744 maintenance records for the thirteen participating plants were processed. Seventy percent of the events were noncurtailing, of which 612 events involved component failures. The data base included 968 failure events to over 200 different combined-cycle plant components each described by a three digit code. Component repairs accounted for over 50 percent of these failures. Detailed descriptions of these failures identifying causes and failed piece parts can be listed by the computer from the “PROBLEMS” DBF using “FRM’s SYSCOMP” (failures grouped by components) or “SYSPLANT” (failures grouped by plant). It is concluded that work orders do provide insight into possible root cause and can assist engineering in followup failure investigations, although discussions with power plant personnel are often required for additional insight into root cause. The extent of successful root cause determination in the ERAS data base is difficult to quantify due to different root cause interpretations. However, project efforts have successfully identified the failed piece part in 86 percent of equipment failures. An analysis of plant reliability problems showed that failures of combustion turbine and heat recovery boiler panel controls and remote sensing equipment are the most frequent cause of combined-cycle plant unavailability. Each plant appears to have specific problem areas generic to these control system failures. Generic problems were observed in drum level set points, control valves, panel cards and timers, computers and data links, flame scanners, and thermo-couples. Many of the control related problems documented in ERAS records identify the failed part number of the control circuit affected. It is expected that these documented control system failures will begin to yield better insight into root cause as the number of records increase, and cause and effect relationships are established.

DEVELOPMENT AND ANALYSIS OF AN INTEGRATED MILD/PARTIAL GASIFICATION COMBINED (IMPGC) CYCLE

2021 ◽  
pp. 1-34
Author(s):  
Ting Wang ◽  
Henry Long
Keyword(s):  
Power Plants ◽  
Energy Content ◽  
Energy Resource ◽  
Rankine Cycle ◽  
High Energy ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Efficient Manner ◽  
Volumetric Heating ◽  
Partial Gasification

Abstract Around 50% of the world's electrical power supply comes from the Rankine cycle, and the majority of existing Rankine cycle plants are driven by coal. Given how unattractive coal is as an energy resource in spite of its high energy content, it becomes necessary to find a way to utilize coal in a cleaner and more efficient manner. Designed as a potential retrofit option for existing Rankine cycle plants, the Integrated Mild/Partial Gasification Combined (IMPGC) Cycle is an attractive concept in cycle design that can greatly increase the efficiency of coal-based power plants, particularly for retrofitting an old Rankine cycle plant. Compared to the Integrated Gasification Combined Cycle (IGCC), IMPGC uses mild gasification to purposefully leave most of the volatile matters within the feedstock intact (hence, yielding more chemical energy) compared to full gasification and uses partial gasification to leave some of the remaining char un-gasified compared to complete gasification. The larger hydrocarbons left over from the mild gasification process grant the resulting syngas a higher volumetric heating value, leading to a more efficient overall cycle performance. This is made possible due to the invention of a warm gas cleanup process invented by Research Triangle Institute (RTI), called the High Temperature Desulfurization Process (HTDP), which was recently commercialized. The leftover char can then be burned in a conventional boiler to boost the steam output of the bottom cycle, further increasing the efficiency of the plant, capable of achieving a thermal efficiency of 47.9% (LHV). This paper will first analyze the individual concepts used to create the baseline IMPGC model, including the mild and partial gasification processes themselves, the warm gas cleanup system, and the integration of the boiler with the heat recovery steam generator (HRSG). This baseline will then be compared with four other common types of power plants, including subcritical and ultra-supercritical (USC) Rankine cycles, IGCC, and natural gas. The results show that IMPGC consistently outperforms all other forms of coal-based power. IMPGC is more efficient than the standard subcritical Rankine cycle by nine percentage points, more than a USC Rankine cycle by nearly four points, and more than IGCC by seven points.

300 MW Combined-Cycle Plant With Integrated Coal Gasification

1984 ◽  
Author(s):  
Rolf H. Kehlhofer
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Gas Turbines ◽  
Power Plants ◽  
Coal Gasification ◽  
District Heating ◽  
Combined Cycle ◽  
Liquid Fuels ◽  
Combined Cycle Plant ◽  
The Individual

In the past 15 years the combined-cycle (gas/steam turbine) power plant has come into its own in the power generation market. Today, approximately 30 000 MW of power are already installed or being built as combined-cycle units. Combined-cycle plants are therefore a proven technology, showing not only impressive thermal efficiency ratings of up to 50 percent in theory, but also proving them in practice and everyday operation (1) (2). Combined-cycle installations can be used for many purposes. They range from power plants for power generation only, to cogeneration plants for district heating or combined cycles with maximum additional firing (3). The main obstacle to further expansion of the combined cycle principle is its lack of fuel flexibility. To this day, gas turbines are still limited to gaseous or liquid fuels. This paper shows a viable way to add a cheap solid fuel, coal, to the list. The plant system in question is a 2 × 150 MW combined-cycle plant of BBC Brown Boveri with integrated coal gasification plant of British Gas/Lurgi. The main point of interest is that all the individual components of the power plant described in this paper have proven their worth commercially. It is therefore not a pilot plant but a viable commercial proposition.

The Air Injection Power Augmentation Technology Provides Additional Significant Operational Benefits

2007 ◽  
Author(s):  
Eiji Akita ◽  
Shin Gomi ◽  
Scott Cloyd ◽  
Michael Nakhamkin ◽  
Madhukar Chiruvolu
Keyword(s):  
Mass Balance ◽  
Power Plants ◽  
Heat Rate ◽  
Combined Cycle ◽  
Air Injection ◽  
Humid Air ◽  
Diffusion Type ◽  
Number Of Factors ◽  
Compressor Surge ◽  
Injection Power

The Air Injection (AI) Power Augmentation technology (HAI for humid Air injection and DAI for dry air injection) has primary benefits of increasing power of combustion turbine/combined cycle (CT/CC) power plants by 15–30% at a fraction of the new plant cost with coincidental significant heat rate reductions (10–15%) and NOx emissions reductions (for diffusion type combustors up to 60%) (See References 1, 2, 3): Figure 1A is a simplified heat and mass balance for the PG7241 (FA) combustion turbine with HAI. The auxiliary compressor supplies the additional airflow that is mixed with the steam produced by the HRSG and injected upstream of combustors. Figure 1B presents the heat and mass balance for the PG7142 CT based combined cycle power plant with HAI. It is similar to that presented on Figure 1A except that the humid air is created by mixing of steam, extracted from the steam turbine, with the supplementary airflow from the auxiliary compressor. The maximum acceptable injection rates are evaluated with proper margins by a number of factors established by OEMs: the compressor surge limitations, maximum torque, the generator capacities, maximum moisture levels upstream of combustors, etc.

Development and Analysis of an Integrated Mild/Partial Gasification Combined (IMPGC) Cycle: Part 1 — Development of a Baseline IMPGC System

2019 ◽  
Author(s):  
Ting Wang ◽  
Henry A. Long
Keyword(s):  
Power Plants ◽  
Energy Content ◽  
Energy Resource ◽  
Rankine Cycle ◽  
High Energy ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Efficient Manner ◽  
Volumetric Heating ◽  
Partial Gasification

Abstract Around 50% of the world’s electrical power supply comes from the Rankine cycle, and the majority of existing Rankine cycle plants are driven by coal. Given how politically unattractive coal is as an energy resource in spite of its high energy content, it becomes necessary to find a way to utilize coal in a cleaner and more efficient manner. Designed as a potential retrofit option for existing Rankine cycle plants, the Integrated Mild/Partial Gasification Combined (IMPGC) Cycle is an attractive concept in cycle design that can greatly increase the efficiency of coal-based power plants, particularly for retrofitting an old Rankine cycle plant. Compared to the Integrated Gasification Combined Cycle (IGCC), IMPGC uses mild gasification to purposefully leave most of the volatile matters within the feedstock intact (hence, yielding more chemical energy) compared to full gasification and uses partial gasification to leave some of the remaining char un-gasified compared to complete gasification. The larger hydrocarbons left over from the mild gasification process grant the resulting syngas a higher volumetric heating value, leading to a more efficient overall cycle performance. This is made possible due to the invention of a warm gas cleanup process invented by Research Triangle Institute (RTI), called the High Temperature Desulfurization Process (HTDP), which was recently commercialized. The leftover char can then be burned in a conventional boiler to boost the steam output of the bottom cycle, further increasing the efficiency of the plant, capable of achieving a thermal efficiency of 47.9% (LHV). The first part of this paper will analyze the individual concepts used to create the baseline IMPGC model, including the mild and partial gasification processes themselves, the warm gas cleanup system, and the integration of the boiler with the heat recovery steam generator (HRSG). Part 2 will then compare this baseline case with four other common types of power plants, including subcritical and ultra-supercritical Rankine cycles, IGCC, and natural gas.

Design of Fast and Reliable Steam Surface Condensers

2020 ◽  
Author(s):  
Ranga Nadig
Keyword(s):  
Steam Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Combined Cycle ◽  
Design Features ◽  
Surface Condenser ◽  
Combined Cycle Plant ◽  
Startup Time ◽  
On Line ◽  
To Come

Abstract Power plants operating in cyclic mode, standby mode or as back up to solar and wind generating assets are required to come on line on short notice. Simple cycle power plants employing gas turbines are being designed to come on line within 10–15 minutes. Combined cycle plants with heat recovery steam generators and steam turbines take longer to come on line. The components of a combined cycle plant, such as the HRSG, steam turbine, steam surface condenser, cooling tower, circulating water pumps and condensate pumps, are being designed to operate in unison and come on line expeditiously. Major components, such as the HRSG, steam turbine and associated steam piping, dictate how fast the combined cycle plant can come on line. The temperature ramp rates are the prime drivers that govern the startup time. Steam surface condenser and associated auxiliaries impact the startup time to a lesser extent. This paper discusses the design features that could be included in the steam surface condenser and associated auxiliaries to permit quick startup and reliable operation. Additional design features that could be implemented to withstand the demanding needs of cyclic operation are highlighted.

Exergy Evaluation of Two Current Advanced Power Plants: Supercritical Steam Turbine and Combined Cycle

1997 ◽  
Vol 119 (4) ◽  
pp. 250-256 ◽  
Author(s):  
H. Jin ◽  
M. Ishida ◽  
M. Kobayashi ◽  
M. Nunokawa
Keyword(s):  
Steam Turbine ◽  
Thermal Efficiency ◽  
Heat Recovery ◽  
Power Plants ◽  
Exergy Analysis ◽  
Combined Cycle ◽  
Exergy Loss ◽  
Heat Recovery Steam Generator ◽  
Combined Cycle Plant ◽  
Steam Plant

Two operating advanced power plants, a supercritical steam plant and a gas-steam turbine combined cycle, have been analyzed using a methodology of graphical exergy analysis (EUDs). The comparison of two plants, which may provide the detailed information on internal phenomena, points out several inefficient segments in the combined cycle plant: higher exergy loss caused by mixing in the combustor, higher exergy waste from the heat recovery steam generator, and higher exergy loss by inefficiency in the power section, especially in the steam turbine. On the basis of these fundamental features of each plant, we recommend several schemes for improving the thermal efficiency of current advanced power plants.

Combined Heat and Power Plants Based on Mirror Heat Exchange Brayton Cycles

2014 ◽  
Author(s):  
Andrea Passarella ◽  
Gianmario L. Arnulfi
Keyword(s):  
Heat Recovery ◽  
Power Plants ◽  
Combined Heat And Power ◽  
Combined Cycle ◽  
Plant Performance ◽  
Higher Power ◽  
Combined Cycle Plant ◽  
Gas Turbine Exhaust ◽  
Interesting Alternative ◽  
Top Cycle

As gas turbine exhaust gases leave the turbine at high temperature, heat recovery is often carried out in a combined heat-and-power system or in the steam section of a combined-cycle plant. An interesting alternative is a mirror cycle, which involves coupling together a direct Brayton top cycle and an inverted Brayton bottom cycle; this results in significantly higher power output and efficiency, though at the expense of added complexity. The research illustrated in the present paper was based on two in-house codes and aimed to analyze different plant configurations, one of which was a heat recovery (regenerative) top cycle with the heat exchanger hot side located between the top and bottom cycle turbo-expanders. The authors call this configuration a distorting mirror, as the hot side may not be at atmospheric pressure. A parametric analysis was carried out in order to optimize plant performance vs. pressure levels. Simulation showed that, at the design point, very good performance is obtained: efficiency close to 0.50 with plant cost (per megawatt) about half vs. combined-cycle plants. An off-design analysis showed that the mirror plant is a little more sensitive to changes in load than a simple Brayton, single-shaft GT.

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