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SCHUMACHER HOT GAS FILTER LONG-TERM OPERATING EXPERIENCE in the NUON POWER BUGGENUM IGCC POWER PLANT

Description: Coal is a main source of primary energy for power generation and it will remain indispensable in the future. In order to increase the efficiency and to meet environmental challenges new advanced coal-fired power systems were developed starting in the beginning of the 1990s. One of these efficient and clean technologies is the Integrated Gasification Combined Cycle (IGCC) process.
Date: September 18, 2002
Creator: Scheibner, B. & Wolters, C.
Partner: UNT Libraries Government Documents Department

Use of Laboratory Drag Measurements in Evaluating Hot-Gas Filtration of Char from the Transport Gasifier at the Power Systems Development Facility

Description: The initial objective of this study was to better understand the reasons for the substantial increase in filter DP that was observed after the gasifier recycle loop modifications. Beyond this specific objective, a secondary goal was to develop a meaningful method of evaluating the effect of particle size and other particle properties on dustcake drag and filter DP. As mentioned earlier, the effect of particle size on dustcake drag and filter DP can be a very important consideration in the selection and specification of a precleaner cyclone for use upstream of the hot-gas filter. Installing a cyclone ahead of a hot-gas filter will reduce the transient areal loading of dust to the filter, but the beneficial effect of the reduced areal loading may be offset by an increase in drag associated with a finer particle-size distribution. The overall goal of this study was to better understand these tradeoffs and to ultimately develop a procedure that would be useful in analyzing the performance of hot-gas filters and in sizing new hot-gas filters. In addition to the obvious effects of a cyclone on dust loading and particle size, other indirect effects on particulate properties and flow resistance may occur when the cyclone is incorporated into the gasifier recycle loop as was the case at the PSDF. To better understand the importance of these other effects, this study sought to separate the particle-size effect from these other effects by measuring the drag of size-fractionated char samples collected before and after the recycle loop modifications.
Date: September 19, 2002
Creator: Dahlin, R.S. & Landham, E.C.
Partner: UNT Libraries Government Documents Department

Power Systems Development Facility: High Temperature, High Pressure Filtration in Gasification Operation

Description: High temperature, high pressure gas filtration is a fundamental component of several advanced coal-fired power systems. This paper discusses the hot-gas filter vessel operation in coal gasification mode at the Power Systems Development Facility (PSDF). The PSDF, near Wilsonville, Alabama, is funded by the U.S. Department of Energy (DOE), Southern Company, and other industrial participants currently including the Electric Power Research Institute, Siemens Westinghouse Power Corporation, Kellogg Brown & Root Inc. (KBR), and Peabody Energy. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems designed at sufficient size to provide data for commercial scale-up.
Date: September 18, 2002
Creator: Martin, R.A.; Guan, X.; Gardner, B. & Hendrix, H.
Partner: UNT Libraries Government Documents Department

Development of Simulation System for Hot Gas Filtration by Ceramic Candle Filters on High Temperature and/or High Pressure Conditions

Description: Hot gas filtration from industrial processes offers various advantages in terms of improvement of process efficiencies, heat recovery and protection of plant installation. Especially hot gas filtration is an essential technology for pressurized fluidized bed combustion (PFBC) and integrated gasification combined cycle (IGCC).
Date: September 19, 2002
Creator: Park, S.J.; Lim, J.H.; Kim, S.D.; Choi, H.K.; Park, H,S. & Park, Y.O.
Partner: UNT Libraries Government Documents Department

Experimental and Numerical Investigations on Flue Gas Purification during Hot Gas Filtration

Description: The aim of the actual investigations is to integrate the catalytic reduction of carbon monoxide and particularly nitric oxides into the hot gas filtration process with ceramic filter elements of fluidized bed combustors which mainly represent an important N2O-source. According to Klein (Klein 1994) worldwide approx. 260 coal-fired power plants with fluidized bed combustors in the power range > 50 MWel existed in 1994, to which approx. 1% of the global coal dissipation corresponds. These emitted dinitrogen oxide with 70 kt/a, however, 20% of the entire N2O amounts from stationary firing plants. After Kleins calculations an increase of coal-fired fluidized bed combustors only by 10% triples the N2O emission.
Date: September 19, 2002
Creator: Thulfaut, C. & Renz, U.
Partner: UNT Libraries Government Documents Department

Ceramic Hot Gas Filter with Integrated Failsafe System

Description: In order to integrate a failsafe system and to improve the cleaning intensity a new cleaning method was recently developed, the CPP (coupled pressure pulse) cleaning (Heidenreich et al. 2001). For the CPP method the cleaning system is directly coupled with the filter candles. One feature of this new technique is that the cleaning gas pressure exceeds the system pressure only by 0.05 to 0.1 MPa, whereas in case of conventional jet pulse systems two times the system pressure (at least 0.6 MPa) is standard. The key advantage of the coupled pressure pulse cleaning is that a safety filter for each filter candle can be integrated in the clean gas side of the filter. Thus, a candle failure is not longer a serious problem. The integrated safety filter enables the operation of the filter system also in case a filter candle breaks. This increases the availability of the filter and prevents an unscheduled costly shut-down of the system. In this paper the design of the ceramic filter wit h the failsafe system and the CPP cleaning will be described. The new developed safety filter elements, their pressure drop and their filtration and clogging behavior will be shown. Tests of single system components, of the whole filter system and first experiences of operating this system will be reported.
Date: September 18, 2002
Creator: Heidenreich, S.; Haag, W.; Walch, A.; Scheibner, B.; Mai, R.; Leibold, H. et al.
Partner: UNT Libraries Government Documents Department

Experiences of the Application of Hot Gas Filtration to Industrial Processes

Description: Hot Gas Filtration (HGF) is defined as the dry scrubbing of gaseous process effluent above 250 degrees. The potential applications for this technology can be found in Atmospheric Pollution Control (APC) and In-Line Equipment Protection (ILETP). In recent years novel rigid refractory filter media have emerged with several advantages over conventional fabric bag filters and other particulate arrestment systems e.g. electrostatic precipitators. A study has been made of the effect of a wide range of operational conditions, including gas volume and velocity, temperature, particle size distribution, and organic/moisture content, in real process situations on filter elements performance and life expectancy.
Date: September 18, 2002
Creator: Lloyd, B.T.
Partner: UNT Libraries Government Documents Department

Predicting the Operating Behavior of Ceramic Filters from Thermo-Mechanical Ash Properties

Description: Stable operation, in other words the achievement of a succession of uniform filtration cycles of reasonable length is a key issue in high-temperature gas filtration with ceramic media. Its importance has rather grown in recent years, as these media gain in acceptance due to their excellent particle retention capabilities. Ash properties have been known for some time to affect the maximum operating temperature of filters. However, softening and consequently ''stickiness'' of the ash particles generally depend on composition in a complex way. Simple and accurate prediction of critical temperature ranges from ash analysis--and even more so from coal analysis--is still difficult without practical and costly trials. In general, our understanding of what exactly happens during break-down of filtration stability is still rather crude and general. Early work was based on the concept that ash particles begin to soften and sinter near the melting temperatures of low-melting, often alkaline components. This softening coincides with a fairly abrupt increase of stickiness, that can be detected with powder mechanical methods in a Jenicke shear cell as first shown by Pilz (1996) and recently confirmed by others (Kamiya et al. 2001 and 2002, Kanaoka et al. 2001). However, recording {sigma}-{tau}-diagrams is very time consuming and not the only off-line method of analyzing or predicting changes in thermo-mechanical ash behavior. Pilz found that the increase in ash stickiness near melting was accompanied by shrinkage attributed to sintering. Recent work at the University of Karlsruhe has expanded the use of such thermo-analytical methods for predicting filtration behavior (Hemmer 2001). Demonstrating their effectiveness is one objective of this paper. Finally, our intent is to show that ash softening at near melting temperatures is apparently not the only phenomenon causing problems with filtration, although its impact is certainly the ''final catastrophe''. There are other significant changes in regeneration ...
Date: September 19, 2002
Creator: Hemmer, G. & Kasper, G.
Partner: UNT Libraries Government Documents Department

Computer Modeling of Flow, Thermal Condition and Ash Deposition in a Hot-Gas Filtration Device

Description: The objective of the present study is to develop a computational model for simulating the gas flow, thermal condition and ash transport and deposition pattern in the hot-gas filtration systems. The computational model is to provide a virtual tool for design and operation modifications. Particular attention is given to the Particle Control Device (PCD) at the Power Systems Development Facility (PSDF) in Wilsonville, Alabama. For evaluation of gas velocity and temperature field in the vessel, the FLUENT commercial CFD computer code is used. Ash particle transport and deposition pattern was analyzed with the Lagrangian particle tracking approach.
Date: September 19, 2002
Creator: Ahmadi, G.; Mazaheri, A.; Liu, C. & Gamwo, I.K.
Partner: UNT Libraries Government Documents Department

Catalytic Cracking of Gaseous Heavy Hydrocarbons by Ceramic Filters

Description: The use of syngas from waste or biomass gasification to generate electricity is a way which is attracting increasing attention especially with regard to the demands of regenerable energy consumption and to the reduction of waste disposal. In order to feed the syngas to a gas motor or a gas turbine the gas has to be cleaned. In future also the coupling of biomass gasification with a fuel cell will be applied, which needs a very efficient gas cleaning. The decomposition of tars and the removal of particles from the gas are the key issues of gas cleaning. Up to now these two steps are performed in two separate units. Normally, the tars are decomposed in catalytic beds or honeycomb structures. The catalytic decomposition is achieved at temperatures between 750 C and 900 C depending on the catalyst used. Particles are removed by filtration of the hot gas. Filtration at high temperatures and with high efficiencies is possible when using ceramic filter elements. Ceramic hot gas filters are well established in advanced coal gasification, such as the integrated gasification combined cycle process, as well as in waste and biomass gasification and pyrolysis processes. Since the catalytic reaction requires high temperatures the gas has to be reheated after the particles are removed in the filter or the hot unfiltered gas has to flow through the catalytic unit. If the gas is filtered first, reheating of the gas stream is an additional cost factor. Furthermore, pipes downstream of the filter can be plugged, if the temperature of the gas falls below the condensation temperature of the heavy hydrocarbons. Using the second way of hot unfiltered gas flows through the catalytic unit, there is the problem of deactivation of the catalyst by deposition of dust at higher dust concentrations. At worst the catalytic ...
Date: September 19, 2002
Creator: Heidenreich, S.; Nacken, M.; Walch, A. & Chudzinski, S.
Partner: UNT Libraries Government Documents Department

A HIGH TEMPERATURE TEST FACILITY FOR STUDYING ASH PARTICLE CHARACTERISTICS OF CANDLE FILTER DURING SURFACE REGENERATION

Description: Hot gas particulate filtration is a basic component in advanced power generation systems such as Integrated Gasification Combined Cycle (IGCC) and Pressurized Fluidized Bed Combustion (PFBC). These systems require effective particulate removal to protect the downstream gas turbine and also to meet environmental emission requirements. The ceramic barrier filter is one of the options for hot gas filtration. Hot gases flow through ceramic candle filters leaving ash deposited on the outer surface of the filter. A process known as surface regeneration removes the deposited ash periodically by using a high pressure back pulse cleaning jet. After this cleaning process has been done there may be some residual ash on the filter surface. This residual ash may grow and this may lead to mechanical failure of the filter. A High Temperature Test Facility (HTTF) was built to investigate the ash characteristics during surface regeneration at high temperatures. The system is capable of conducting surface regeneration tests of a single candle filter at temperatures up to 1500 F. Details of the HTTF apparatus as well as some preliminary test results are presented in this paper. In order to obtain sequential digital images of ash particle distribution during the surface regeneration process, a high resolution, high speed image acquisition system was integrated into the HTTF system. The regeneration pressure and the transient pressure difference between the inside of the candle filter and the chamber during regeneration were measured using a high speed PC data acquisition system. The control variables for the high temperature regeneration tests were (1) face velocity, (2) pressure of the back pulse, and (3) cyclic ash built-up time.
Date: September 19, 2002
Creator: Kang, B.S-J.; Johnson, E.K. & Rincon, J.
Partner: UNT Libraries Government Documents Department

Development and Behavior of Metallic Filter Element and Numerical Simulation of Transport Phenomena during Filter Regeneration Process

Description: Ceramic filters have revealed to have good thermal resistance and chemical corrosion resistance, but they are brittle and lack of toughness, and liable to rupture under large temperature swings. Metallic filters with their high strength and toughness and good heat conduction ability have showed good thermal shock resistance, 310S and FeAl intermetallic filter elements have exhibited additionally good chemical corrosion resistance in oxidizing and sulfidizing atmosphere( Sawada 1999 and Sunil et al. 1999). The behavior of metallic filter elements at high temperature was investigated and the filtration efficiency of the filter units for hot gas from a coal gasifier unit was tested. Pulse-jet cleaning of filter elements is a key component in the operation of the filtration unit. The pulse-jet is introduced into the filter element cavities from the clean side, and the dust cakes on the outer surfaces of the filter elements are detached and fall into the filter vessel. Sequential on-line cleaning of filter element groups yields a filter operation with no shutdown for filter regeneration. Development of advanced technologies in the design and operation of the pulse cleaning is one of the important tasks in order to increase the system reliability, to improve the filter life and to increase the filtering performance. The regeneration of filter element in gas filtration at high temperature plays a very important role for the operation of the process. Based on experimental observation and field operation, a numerical model is set up to numerically simulate the momentum and heat transport phenomena in the regeneration process, which is essential for understanding of the process, the optimization of process parameters and improvement of the design of the structure of venturi nozzle and the configuration of the apparatus.
Date: September 19, 2002
Creator: Kuang, C.; Zhang, J.; Wang, F. & Chen, J.
Partner: UNT Libraries Government Documents Department

A STUDY ON ASH PARTICLE DISTRIBUTION CHARACTERISITICS OF CANDLE FILTER SURFACE REGENERATION AT ROOM TEMPERATURE

Description: Ceramic barrier filtration is a leading technology employed in hot gas filtration. Hot gases loaded with ash particle flow through the ceramic candle filters and deposit ash on their outer surface. The deposited ash is periodically removed using back pulse cleaning jet, known as surface regeneration. The cleaning done by this technique still leaves some residual ash on the filter surface, which over a period of time sinters, forms a solid cake and leads to mechanical failure of the candle filter. A room temperature testing facility (RTTF) was built to gain more insight into the surface regeneration process before testing commenced at high temperature. RTTF was instrumented to obtain pressure histories during the surface regeneration process and a high-resolution high-speed imaging system was integrated in order to obtain pictures of the surface regeneration process. The objective of this research has been to utilize the RTTF to study the surface regeneration process at the convenience of room temperature conditions. The face velocity of the fluidized gas, the regeneration pressure of the back pulse and the time to build up ash on the surface of the candle filter were identified as the important parameters to be studied. Two types of ceramic candle filters were used in the study. Each candle filter was subjected to several cycles of ash build-up followed by a thorough study of the surface regeneration process at different parametric conditions. The pressure histories in the chamber and filter system during build-up and regeneration were then analyzed. The size distribution and movement of the ash particles during the surface regeneration process was studied. Effect of each of the parameters on the performance of the regeneration process is presented. A comparative study between the two candle filters with different characteristics is presented.
Date: September 19, 2002
Creator: Vasudevan, V.; Kang, B.S-J. & Johnson, E.K.
Partner: UNT Libraries Government Documents Department

A Simple Candle Filter Safeguard Device

Description: In order to reach the highest possible efficiencies in a coal-fired turbine-based power system, the turbine should be directly fired with the products of coal utilization. Two main designs employ these turbines: those based on pressurized fluidized-bed combustors (PFBCs) and those based on integrated gasification combined cycles (IGCCs). In both designs, the suspended particulates, or dust, must be cleaned from the gas before it enters the turbine to prevent fouling and erosion of the blades. To produce the cleanest gas, barrier filters are being developed and are in commercial use. Barrier filters are composed of porous, high-temperature materials that allow the hot gas to pass but collect the dust on the surface. The three main configurations are candle, cross-flow, and tube. Both candle and tube filters have been tested extensively. They are primarily composed of coarsely porous ceramic that serves as a structural support, overlain with a thin, microporous ceramic layer o n the dirty gas side that serves as the primary filter surface. They are highly efficient at removing particulate matter from the gas stream and, because of their ceramic construction, are resistant to gas and ash corrosion. However, ceramics are brittle, and individual elements can fail, allowing the particulates to pass through the hole left by the filter element and erode the turbine. Because of the possibility of occasional filter breakage, safeguard devices (SGDs) must be employed to prevent the dust streaming through broken filters from reaching the turbine. The Energy & Environmental Research Center (EERC) safeguard device is composed of three main parts: the ceramic substrate, the adhesive coating, and the safeguard device housing. This report describes the development and laboratory testing of each of those parts as well as the bench-scale performance of both types of complete SGDs.
Date: September 18, 2002
Creator: Hurley, J. P.; Henderson, A. K. & Swanson, M. L.
Partner: UNT Libraries Government Documents Department