Method for cooling a humid gas and a device for the same

Abstract

Cooling performance of a cooler for pre-cooling humid gas supplied to a gas turbine power generation plant, etc. is improved by increasing heat transfer efficiency between the humid gas and cooling liquid flowing in heat exchanger tubes with utilization of condensed liquid generated due to the cooling of the humid gas. In a heat exchanger for cooling humid gas a flowing surrounding heat exchanger tubes 8 of the tube groups 9 a and 9 b by flowing cooling liquid r in the tubes, the liquid droplets c 1 generated by condensation of moisture contained in the humid gas are gathered and sprinkled or fallen in drops on a part of the heat exchanger tube group 9 b , which results in increased heat exchange efficiency.

What is claimed is: 
     
         1 . A method of cooling humid gas in a heat exchanger through heat exchange between the humid gas flowing outside of heat exchanger tubes of a group or groups and cooling liquid flowing in the heat exchanger tubes, wherein liquid condensed from moisture in the humid gas by condensation is gathered and the gathered liquid is sprinkled or allowed to fall in drops on a part of the tube group or on a part of one of the tube groups thereby increasing heat exchange performance. 
     
     
         2 . A heat exchanger comprising a casing and heat exchanger tubes arranged inside the casing to cool humid gas through heat exchange between the humid gas flowing in the casing and cooling liquid flowing in the heat exchanger tubes, wherein
 the heat exchanger tubes are arranged as a tube group or tube groups in the casing, and   a means for allowing cooling water to be sprinkled or fallen in drops on a part of the tube group or part of at least one of the tube groups so that films of the liquid are formed on surfaces of said part of the heat exchanger tubes.   
     
     
         3 . A heat exchanger according to  claim 2 , wherein the heat exchanger tubes extend along the flow path, and the cooling liquid flows inside the heat exchanger tubes in a direction opposite to a flow direction of the humid gas in the flow path. 
     
     
         4 . A heat exchanger according to  claim 3 , wherein
 the heat exchanger is an upright-mounted one, a cooling liquid inlet and a cooling liquid outlet are provided such that the cooling liquid is introduced to the heat exchanger tubes from lower ends thereof to flow up therein and discharged from upper ends thereof,   a humid gas inlet and outlet are provided at an upper and lower part respectively of the casing,   a plurality of baffle plates are provided inside the casing at a proper spacing such that an opening is formed between an end of each baffle plate and the inside surface of the casing with the other end of connecting to the inside surface so that the humid gas introduced from the humid gas inlet flows down snaking in the casing, and each of the baffle plates except a lowest positioned one is inclined toward the opening so the condensed liquid generated from moisture contained in the humid gas received on each of the baffle plates flows on the surface thereof and flows down through the openings, and   the lowest positioned baffle plate is provided horizontally at a position upper than the gas outlet in the casing and has a number of small holes,   whereby liquid generated by condensation of moisture contained in the humid gas fallen down on the lowest baffle plate is allowed to be sprinkled or fallen in drops through the small holes and liquid films are formed on surfaces of the heat exchanger tubes in a region below the lowest positioned baffle plate.   
     
     
         5 . A heat exchanger according to  claim 3 , wherein the heat exchanger is an upright-mounted one, inside of the casing is divided into a left and a right heat exchanger region by an upright partitioning plate with a top side opening provided for allowing communication between the left and right heat exchange regions,
 a cooling liquid inlet and a cooling liquid outlet are provided such that the cooling liquid is first introduced to the heat exchanger tubes of one of both tube groups from lower ends thereof to flow up in the tubes and then introduced to the heat exchanger tubes of the other one of both tube groups from upper ends thereof to flow down in the tubes,   a humid gas inlet is provided in the casing at a part adjacent to the cooling liquid outlet and a humid gas outlet is provided in the casing at a part adjacent to the cooling liquid inlet,   a plurality of baffle plates are provided inside the casing at a proper spacing such that the humid gas introduced from the humid gas inlet flows up snaking in one of heat exchange region and then flows down snaking in the other one of the heat exchange region to be discharged from the humid gas outlet, that flow direction of the humid gas is opposite to that of the cooling liquid, and that liquid generated by condensation of moisture contained in the humid gas falls down by way of the upper surfaces of the baffle plates positioned above a lowest positioned baffle plate which is provided at a position slightly upper than the humid gas inlet, and   a number of small holes are made in the lowest positioned baffle plate,   whereby the liquid received on the lowest positioned baffle plate provided at a position slightly above the humid gas inlet is allowed to be sprinkled or fallen in drops through the holes and liquid films are formed on surfaces of apart of the heat exchanger tubes in a region below the lowest positioned baffle plate.   
     
     
         6 . A heat exchanger according to  claim 3 , wherein
 the heat exchanger consists of a plurality of horizontal heat exchangers arranged above and below,   the cooling liquid outlet of an upper heat exchanger is connected to the cooling liquid inlet of a lower heat exchanger disposed under the upper one via a connecting pipe and the humid gas outlet of the lower heat exchanger is connected to the humid gas inlet of the upper one via a connecting pipe,   the lower heat exchange region of the upper heat exchanger is connected to the upper heat exchange region of the lower heat exchanger via a connecting pipe so that liquid generated from moisture contained in the humid gas by condensation flowing in the upper heat exchanger is introduced to the upper heat exchange region of the lower heat exchanger,   a tray having a number of small holes is provided in the upper heat exchange region of the lower heat exchanger below a condensed liquid inlet above the opening communicating the upper heat exchange region to the lower heat exchange region of the lower exchanger,   whereby the liquid received on the tray is allowed to be sprinkled or fallen in drops through the holes and liquid films are formed on surfaces of a part of the heat exchanger tubes in a region below the tray.