Gas separation – Two or more separators – Plies or layers of different characteristics or orientation
Reexamination Certificate
2001-04-18
2003-04-01
Simmons, David A. (Department: 1724)
Gas separation
Two or more separators
Plies or layers of different characteristics or orientation
C055S385300, C055S487000, C055S498000, C055S521000, C095S286000, C095S287000
Reexamination Certificate
active
06540805
ABSTRACT:
BACKGROUND OF THE INVENTION
1 . Field of the Invention
The present invention relates to a filter unit for an intake air for a gas turbine, which is designed to remove atmospheric dusts, whereby the deposition of the dusts in an air compressor or the like in a gas turbine plant can be alleviated, thereby preventing a reduction in power-generating output and ensuring that it is unnecessary over a long period to carry out the washing or cleaning of the air compressor and the like and the replacement of a filter, and more particularly, to a high-performance filter for an intake air for a gas turbine and a filter unit using such high-performance filter for an intake air for a gas turbine, which can be placed in a reduced space.
2. Description of the Related Art
As shown in
FIG. 8
, a gas turbine a draws the open air b during operation thereof. Atmospheric dusts such as fine dusts, rainwater, mists, fine carbon particles in an exhaust gas, salt particles and the like are in suspension in the open air b, Therefore, there is encountered a problem such atmospheric dusts cause the corrosion and pollution of the inside of the gas turbine, and are deposited particularly on an air compressor c to produce a reduction in performance of the air compressor c to reduce the power-generating output. To previously prevent the drawing-in of the atmospheric dusts, a dust collector or a filter unit e for mechanically separating off the atmospheric dusts from the air to clean the air is placed in an air intake port d in the gas turbine a. The filter unit e is formed into two stages of a coarse filter f made of a rolled band-shaped type glass fiber material, and a medium-performance filter g comprising an ion-exchange fiber filter formed into a folded-type, as disclosed in Japanese Patent Application Laid-open No. 5-106464.
In
FIG. 8
, reference character h designates a turbine section of the gas turbine, and reference character i designates a generator driven by the gas turbine a. In the conventional filter unit for the intake air for the gas turbine, it is impossible to sufficiently remove the atmospheric dusts and hence, a reduction in power-generating output from the gas turbine is produced. In addition, the conventional filter unit is of a small dust holding capacity and hence, it is necessary to replace the filter frequently, e.g., 2 to 3 times a year. For this reason, it is desired to propose a high-efficiency and long-life filter unit for an intake air for a gas turbine, which cannot cause a reduction in power-generating output and in which the filter is only required to be replaced at the time of a regular inspection of the gas turbine obliged to be carried out one time a year.
The present inventors have proposed a filter unit of a four-stage type comprising a panel-type demister or a weather louver, a rolled band-shaped type or blow-through type pre-filter, a box-shaped medium-performance filter, and a box-shaped high-performance filter to meet the above demand. However, such filter unit suffers from a problem that its size is increased, resulting in a widened placement space and an increased equipment cost and hence, a countermeasure is required. Therefore, the present inventors have reached a conclusion that a medium-performance filter and a high-performance may be used in combination from the viewpoints of a low pressure drop, a high efficiency and a long life, and they have referred to prior art techniques concerned with the combination of filters. However, each of such prior art techniques has a problem. More specifically, it is disclosed in Japanese Utility Model Application Laid-open No. 562-132715 that for the purpose of reducing the space for placement of a filter unit, a filter paper having a predetermined collection efficiency is placed at a location downstream in a direction of a air flow within a casing, and filter papers having a collection efficiency lower than that of the downstream-side filter paper are placed at multiple stages at a location upstream of the downstream-side filter paper. However, the filter is not reduced in size and hence, it is impossible to achieve the purpose of reducing the placement space.
It is disclosed in Japanese Utility Model Publication No. H3-35373 that for the purpose of removing salt particles, a spacer having voids is interposed between two filter media having a water-repellency. The arrangement of such filter is intended to ensure that even if the salt particles are converted into liquid drops, the liquid drops are permitted to be dropped along a back of the filter media located on an upstream side. However, the thickness of the filter media is increased, and the area of the filter media cannot be increased in order to provide a life of 8,000 hours or more, and additionally, the pressure drop is increased.
It is disclosed in Japanese Patent Application Laid-open No. 554-94176 that for the purpose of provide a high efficiency of filtration (0.1 &mgr;m DOP) of 99.99% or more (so-called ULPA), a filter is formed in two layers, namely, a filter media having an filtration efficiency of 99.97% or more for particles having a particle size of 0.3 &mgr;m is disposed as the layer downstream in a direction of a air flow, and a filter media having a filtration efficiency lower than 99.97 and equal to or higher than 75% for particles having a particle size of 0.3 &mgr;m is disposed as the upstream layer, and the two filter media are folded in a zigzag fashion in closely superposed states. In this case, the filter is formed in the two layers from the viewpoints of the limitation of size and the ease to make, as compared with a filter unit formed at two stages. In this filter, however, it is an object to provide a high efficiency, but the life is not taken into consideration. When the filter is used in a gas turbine, the filter is clogged earlier and hence, it is necessary to carry out the replacement of the filter two or three times a year.
Therefore, in order to solve the above-described problems, the present inventors has proposed a high-performance filter for an intake air for a gas turbine, as disclosed in Japanese Patent Application Laid-open No. 7-253029, in which a low-efficiency filter media and a high-efficiency filter media are superposed closely on each other from an upstream side in a direction of a air flow, each of the filter media being formed with a filtering area of 25 to 35 m
2
, so that the filter media having a filtration efficiency of 10 to 70% for particles having a particle size of 0.3 &mgr;m is disposed as a layer upstream in the air flow direction, and the filter media having a filtration efficiency of 90 to 99.99% for particles having a particle size of 0.3 &mgr;m is disposed as a downstream layer.
For atmospheric dusts used for the first estimation of the filter, an excellent effect indicating a life of 8,000 hours or more has been provided. However, when the re-estimation of the filter has been carried out using other atmospheric dusts, it has been made clear that the pressure drop in the filter unit has been suddenly increased after lapse of about 4,300 hours, resulting in a shorter life. This is because the concentration of the fine dusts having the typical particle size of 0.3 &mgr;m is as very high as about 5 times that of the dusts used in the first estimation and for this reason, the load has been concentrated on the downstream layer.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a filter for an intake air for a gas turbine and a filter unit using such filter for an intake air for a gas turbine, which can be placed in a reduced space, wherein even if the filter unit is used for high-concentration fine atmospheric dusts having a typical particle size of 0.3 &mgr;m, a life of 8,000 hours or more can be ensured, and a reduction in power-generating output can be prevented by alleviating the deposition of the atmospheric dusts in an air compressor or the like in the conventional gas turbine plate, thereby ensuring that it is unnecessary over a long period of time to carry out the w
Nakajima Fumio
Niinuma Hitoshi
Ohno Katsuhiro
Armstrong Westerman & Hattori, LLP
Nippon Muki Co., Ltd.
Pham Minh-Chau T.
Simmons David A.
LandOfFree
High-performance filter for intake air for gas turbine, and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with High-performance filter for intake air for gas turbine, and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High-performance filter for intake air for gas turbine, and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3066064