WO2008061686A1

WO2008061686A1 - A gas intake system

Info

Publication number: WO2008061686A1
Application number: PCT/EP2007/009982
Authority: WO
Inventors: Léon Cuvelier
Original assignee: Donaldson Company, Inc.
Priority date: 2006-11-20
Filing date: 2007-11-19
Publication date: 2008-05-29

Abstract

A gas intake system as subject of the present invention comprises: a gas intake for taking in gas, a gas filter located downstream the gas intake and a gas chiller for chilling intake gas, the gas chiller having an inflow side for receiving intake gas and an outflow side for providing chilled gas to the gas filter, the gas chiller for chilling intake gas being adapted to provide chilled gas having a dry bulb temperature and a wet bulb temperature, the dry bulb temperature being larger than the wet bulb temperature of the chilled gas. The gas chiller comprises a gas distributor to divide the intake gas in a first gas stream and a second gas stream. The gas chiller has a direct contact chiller for chilling the first gas stream by directly contacting of the first gas stream with a chilling fluid, and has a guide for guiding the second gas stream to the outflow side. The guide prevents the second gas stream to directly contact the chilling fluid. The first and the second gas stream are merged for providing chilled gas at the outflow side of the gas chiller.

Description

A GAS INTAKE SYSTEM

Technical field of the invention

The present invention relates to a gas intake system, such as an air intake system, e.g. a gas intake system of a gas compression system and/or a turbine unit, e.g. a turbine unit combusting combustible gasses. The present invention further relates to a method of operating a gas intake system, e.g. for increasing the loading time of a gas filter of such a gas intake system or to avoid pressure peaks over a gas filter, and to a method to reduce the temperature of the gas provided to the gas compressor of a gas compression system, e.g. an existing gas compression system.

Background of the invention

Air intake systems, which form part of larger systems such as gas intake systems or turbine units, are well known for many years. Similar gas intake systems used in industrial processes, usually chemical processes, where process gas is to be compressed, are known.

The gas intake systems usually comprise some major components installed in this order in gas flow direction: a gas intake or gas pickup means, a gas filter and optionally, a gas conditioning means, each means having its own particular function.

As an example an air intake system of a turbine unit comprises an air pickup means. The air pickup means or air intake is the most upstream part of the system, via which air from the environment, or ambient air, is taken in. The air pickup means comprises several parts which e.g. prevent dangerous parts to be drafted in with the air intake. Means are provided to prevent e.g. rain and snow and alike to enter into the air intake. A set of sheds may be provided to prevent entrance of rain and snow in the air pickup means of an air intake system, e.g. of a turbine unit. The air pickup means may optionally, comprise a defogging means to prevent water droplets and alike to be drafted in the compression system.

Further downstream in the air stream direction, an air filter for removal of larger and smaller contaminants and particles from the ambient air is provided. This air filter ensures that the air provided to the downstream elements does not comprise particles, which may harm these elements, such as e.g. sand particles and alike, which may harm e.g. turbine or compressor blades and alike. Behind this air filter, the air conditioning means may be installed. After the air filter, a compressing means such as an air compressor may be provided. Air intake system and air compressor together are considered the air compression system which itself may be part of e.g. a turbine unit, e.g. a gas turbine unit, which turbine unit further comprises a combustion chamber and a turbine, which turbine drives the compressing means, and which turbine drives machinery such as generators for providing electric current and alike. Optionally, between the air filter and the compressing means, a silencing unit may be installed.

It is known that gas turbine operating power is sensitive to the inlet combustion air temperature. Cooled air is denser and therefore gives the turbine a higher mass-flow rate and pressure ratio resulting in increased turbine output and efficiency.

Several techniques are known to increase the power output capacity such gas turbines. Often cooling of intake air is used, e.g. in hot geographical regions such as desert. As an example, Donaldson Company (Minneapolis USA) supplies evaporative coolers and chiller coil systems to be installed between the air filter and the compressing means to provide colder, i.e. more dense air to the compressing means. These evaporative coolers and/or chiller coil systems are considered to be an air conditioning means. Cooling water is either made by means of mechanical compressors, absorption chillers recuperating waste heat or ice storage. Optionally ambient water at ambient temperature can also be considered providing the adiabatic exchange only. Foggers are also used as part of possible air conditioning means to inject water droplets within the ducting upstream the compressing means and downstream the air filter to reduce the inlet temperature from the dry towards the wet bulb temperature of the air provided to the compressing means. The air conditioning means may further comprise anti-icing means, and many other elements. The known air intake systems have the disadvantage that the air filter needs frequent cleaning in order to keep the back pressure within acceptable ranges. The cleaning of the air filter may cause downtime of the air intake system and optionally the whole system of which the air intake system is part of, causing economical losses. The build up of contaminants and particles in the air filter itself cause a pressure drop over the filter to raise, which may cause yield decrease of both the compression system and the system of which the air intake system is part of.

Even in case self cleaning filters such as the Donaldson GDX are used, plugging of air filters may occur. Increases of pressure drop over the air filter frequently occurs, e.g. when the air filter is suffering of clay pollution and/or when the air intake system of the air intake system takes in air loaded with hanging fog, staying at the height of the air intake. The latter may cause temporary increased pressure drops over the air filter. E.g. when the filter is loaded with clay, heavy soot or cement, the clay, heavy soot or cement may partially liquefy due to the moisture of the fog, and spread and clog the filter to a larger extent. When the fog has disappeared and the ambient humidity is returned to lower levels, the pressure drop peak may disappear completely or partially. Sometimes the contaminants, when deliquefied, can be recrystallised and may be difficult to dislodge, causing the pressure drop peak disappear only partially. In industrial process, process effluents may load the air filter, such as NaOH effluents, gas pit flare separating CaSO4 in nuclei with Ca and reforming on the filter media with S, or the limestone separating in nuclei form when provided to a steel mill bath to absorb the sulphur and alike. The process effluents may create clogging contamination on the filter as well, in case they are combined with a humidity which is too high.

Also cogeneration means supplying electricity and steam to process industries such as refineries releases pollutants such as ammonia and sulfur which may recristallize and clog the air filter and/or crystallise downstream the filter and foul the compressor blade, generating significant power loss. Eliminating or reducing one of the gases can prevent this event, which event is negative for the process downstream the filter.

Similar problems occur for gas intake systems in industrial processes where gas is to be compressed.

Summary of the invention

It is an object of the present invention to provide good gas intake systems, e.g. those that have a reduced filtration load on the gas filter in the gas intake systems and/or those that avoid pressure peaks due to moisture on gas filters of the gas intake system, as well as methods of operating and constructing such gas intake systems. It is also an advantage of the present invention to provide gas intake systems, which enable the reduction or elimination, i.e. removing from the gas stream, of some elements which might generate pressure peaks at the gas filter due to moisture or provision of saturated gas to the filter, while optionally allowing the reduction of the gas temperature.

The above objective is accomplished by a method and device according to the present invention. According to a first aspect of the present invention, a gas intake system comprises

• a gas intake for taking in gas,

• a gas filter located downstream the gas intake and

• a gas chiller for chilling intake gas, the gas chiller having an inflow side for receiving intake gas and an outflow side for providing chilled gas to the gas filter, the gas chiller for chilling intake gas being adapted to provide chilled gas having a dry bulb temperature and a wet bulb temperature, the dry bulb temperature being larger than the wet bulb temperature of the chilled gas,

The gas chiller comprises a gas distributor to divide the intake gas in a first gas stream and a second gas stream, the gas chiller having a direct contact gas chiller for chilling the first gas stream by directly contacting the first gas stream with a chilling fluid. The gas chiller has a guide for guiding the second gas stream to the outflow side, the guide preventing the second gas stream to directly contact the chilling fluid. The first gas stream and the second gas stream merge at the outflow side of the gas chiller for providing the chilled gas at the outflow side of the gas chiller.

According to some embodiments, the gas chiller for chilling intake gas may be adapted to adjust the dry bulb temperature and/or the wet bulb temperature, for providing the dry bulb temperature being larger than the wet bulb temperature of the chilled gas.

According to some embodiments, V1 being the flow or "volume per time unit" of chilled gas provided by the first gas stream and V2 being the flow or "the volume per time unit" of chilled gas provided by the second gas stream, the ratio V1/V2 may be adapted to provide the dry bulb temperature being larger than the wet bulb temperature of the chilled gas.

According to some embodiments, the gas chiller for chilling intake gas may be adapted to chill intake gas to a dry bulb temperature differing from the wet bulb temperature of the chilled gas according to a preset condition. The preset conditions for the difference between dry bulb temperature and wet bulb temperature of the chilled gas may depend on the position of these temperatures on a psychometric diagram in case the gas is air. In case the gas is air, e.g. ambient air, the dry bulb temperature of the chilled air may be significantly less than the dry bulb temperature of even the wet bulb temperature of the ambient air.

According to some embodiments, the gas chiller further may comprise a flow rate regulator for adjusting the flow ratio of the first gas stream and the second gas stream. The flow ratio is to be understood as the flow of the first gas stream divided by the flow of the second gas stream.

According to some embodiments, the flow rate regulator may be adapted to adjust the flow rate of the first gas stream and/or the second gas stream in function of the dry bulb temperature and/or the wet bulb temperature of the chilled gas at the outflow side of the gas chiller.

According to some embodiments, the flow rate regulator may be adapted to adjust the flow rate of the first gas stream and/or the second gas stream in function of the ambient temperature. According to some embodiments, the flow rate regulator may be adapted to adjust the flow rate of the first gas stream and/or the second gas stream in function of the temperature of the chilling fluid, either the temperature of the chilling fluid at entry of the direct contact chiller, the temperature of the chilling fluid at outlet of the direct contact chiller, or both.

It is understood that adjustment of the flows may be done in function of a combination of the above-mentioned parameters.

According to some embodiments of the present invention, the guide preventing the second gas stream to directly contact the chilling fluid may be provided with one or a plurality of channels, e.g. one or a plurality of tubular guides, such as tubes.

The guide, e.g. each of the channels or optionally tubes, may be provided with one or more inertia separators, such as spin vanes. Each of the channels may comprise one or more spin vanes. The inertia separators, e.g. spin vanes, are optionally installed at the entrance or near the inflow side of the second guide, optionally at the entrances or near the inflow side of the one or the plurality of channels.

Spin vanes cause the gas stream entering and flowing in the second guide to spin, hence to come into contact with the inner surface of the guide for condensing moisture, present in the gas stream, on the inner surface. The spin vanes may generate a vortex and force micro droplets in the gas to move outwards to the inner surface of the guide, e.g. tube, to which they will condense, forming larger droplets. Improved condensate elimination in the gas stream, and an improved mixing of the gas within the guide, may be obtained. As such, since a larger amount of moisture may be condensed from the second gas stream, the amount of moisture guided via the second guide to the downstream merging of the first and second gas stream, may further be reduced. The risk of oversaturating a filter located downstream the intake may be further reduced. A similar effect is obtained using inertia separators other than spin vanes.

This is in particular advantageous when the intake gas is air such as ambient air, which air is nearly or completely saturated, e.g. in foggy ambient. The provision is in particular useful in case the chilling fluid used in the direct chiller is used at ambient temperature. A chilling fluid temperature less than ambient temperature is, however, favoured.

The provision of inertia separators, such as spin vanes, is particularly useful when high gas flows are used, e.g. gas flows in the guide of more than

3m/sec, even more than 5m/sec.Spin vanes may be installed also near the exit of the guide, such as near the exit of the tube. This may improve the mixing of the first and second gas stream when merging both gas streams, e.g. at the outflow side of the gas chiller. An improved mixing of the two gas streams may reduce or even avoid temperature stratification downstream the outflow side of the gas chiller.

As a safety measure, in order to avoid excessive moisture and/or oversaturated gas to pass the gas chiller and enter in downstream elements of the system (e.g. a gas intake system or, more general, a gas or air compression system or a turbine unit, of which the gas chiller is part) absorption media may be installed at the outflow side of the gas chiller. As an example, absorption media with open flute channels or a mist eliminator can be installed. Absorption media with open flute channels, the channels being unparallel to the gas flow direction, cause moisture to be caught by the absorption medium (and drained away by diffusion in the medium), while gas may flow through the medium and the channels.

Absorption media with open flute channels or a mist eliminator may also improve the mixing of the two gas streams at the outflow side of the gas chiller.

According to some embodiments, the guide may be an indirect heat exchanger for chilling the second gas stream.

According to some embodiments, the cooling fluid of the indirect heat exchanger may be the chilling fluid of the direct contact chiller.

According to some embodiments, the chiller may comprise a cooling or chilling fluid regulator for adjusting the temperature and/or the flow per time unit of cooling fluid provided to the chiller.

According to some embodiments, the gas intake system may be an air intake system, optionally an air intake system of an air compressions system or of a turbine unit. According to some embodiments, the gas intake system may be the gas intake system of a turbine unit.

According to a second aspect of the present invention, a gas chiller is provided having an inflow side for receiving intake gas and an outflow side for providing chilled gas, the gas chiller comprising a gas distributor to divide the intake gas in a first gas stream and a second gas stream, the gas chiller comprising a gas collector for merging the first gas stream and the second gas stream at the outflow side of the gas chiller. The gas chiller comprises

• a direct contact chiller for chilling the first gas stream by directly contacting of the first gas stream with a chilling fluid, the direct contact chiller comprises a package, e.g. a package of perforated sheets, and a liquid provider for providing chilling liquid to the package, the package providing a plurality of hollow sections for guiding the first gas stream from the inflow side to the outflow side while allowing direct contact between the chilling fluid and the first gas stream,

• a guide for guiding the second gas stream to the outflow side, the guide preventing the second gas stream to directly contact the chilling fluid, the guide comprising at least one tube extending through one of the hollow sections of the direct contact chiller.

According to some embodiments of the gas chiller, the package of the direct contact chiller may comprise at least two package sections, mounted consecutively in flow direction of the first gas stream. Optionally, at least the most downstream portion of the package, e.g. the package section most downstream, is not provided with chilling water, in order to reduce the risk of entraining chilling water downstream by the first gas stream. According to some embodiments of the gas chiller, a void space may be provided between two consecutive package sections.

According to some embodiments of the gas chiller, the at least one tube may comprise two consecutive tube sections. According to some embodiments of the gas chiller, the at least one tube may comprise two consecutive tube sections, between two consecutive tube sections a slits is provided extending in the in a void spaces between two consecutive package sections. According to some embodiments of the gas chiller, a gas provider for providing the chilled gas, e.g. to the gas filter, with most uniform temperature profile to prevent machinery unbalance may be provided.

According to some embodiments of the gas chiller, the guide may comprise a multitude of tubes, the tubes being substantially equally distributed throughout the gas chiller for preventing temperature stratification downstream.

According to some embodiments of the gas chiller, the package of the direct contact chiller may comprise at least two package sections, mounted one after the other in the chilling fluid flow direction, which is typically parallel to the vertical direction. Each section is provided with a chilling liquid provider and fluid outlet. As such, the temperature increase of the chilling fluid between liquid provider and fluid outlet is reduced. This has as an effect that the temperature differences between gas of the first gas stream and chilling liquid is kept within smaller ranges, resulting in smaller chilled gas temperature gradients measured in a plane perpendicular to the flow direction of the first gas stream. Too large temperature gradients may cause stratification of the gas or air stream.

According to some embodiments of the gas chiller, the gas chiller may be the gas chiller of a turbine unit.

According to some embodiments of the gas chiller, the gas chiller may be an air chiller for chilling ambient air. The air chiller may be a part of a turbine unit, providing chilled air in the turbine unit.

The gas chiller according to embodiment of the second aspect of the present invention may be used to provide the gas intake system according to embodiments of the first aspect of the present invention. The gas chiller according to embodiments of the second aspect of the present invention may be mounted upstream the gas filter, where it has the advantage that the risk on moistening of the gas filter is reduced or even avoided. The gas chiller according to the second aspect of the present invention may also be mounted downstream the gas filter. The gas chiller according to the second aspect of the present invention may also be mounted between the gas filter and the gas compressor. Such mounting has the advantage that the gas intake system has an increased reliability because the risk on providing gas comprising moist droplets to the gas compressor is reduced or even avoided. Hence by reducing or avoiding droplets, damage and harm to the elements of the gas compressor, such as blades of the compressor, may be avoided to a large extent. The gas chiller according to embodiments of the second aspect of the present invention may be provided with inertia separators such as spin vanes or other elements, similar or identical to gas chillers being part of a gas intake system according to embodiments of the first aspect of the present invention.

According to a third aspect of the present invention, a method for taking in gas in a gas intake system is provided, the gas intake system comprising

• a gas intake for taking in gas;

• the gas filter located downstream the gas intake;

• a gas chiller between gas intake and gas filter, which gas chiller is adapted to divide the intake gas into a first gas stream and a second gas stream. The method comprises the steps of

• dividing the intake gas into a first gas stream and a second gas stream; • chilling the first gas stream by directly contacting of the first gas stream with the chilling fluid, guiding the second gas stream to the outflow side while preventing the second gas stream to contact the chilling fluid directly;

• merging the first gas stream and the second gas stream at the outflow side to provide chilled gas having a dry bulb temperature and a wet bulb temperature, the dry bulb temperature being larger than the wet bulb temperature of the chilled gas; • providing the chilled gas to the gas filter.

Optionally means may be provided for providing the chilled gas to the gas filter with most uniform temperature profile to prevent machinery unbalance. In order to avoid stratification of the gas or air stream, which may cause vibrations and alike in the air intake system and in the parts of the process system downwards the air intake system, optionally a gas collector, e.g. a gas mixer may be provided to distribute and mix the second gas stream as uniformly as possible in the first gas stream. Such gas collector might be a uniform location or distribution of the guide, e.g. tubes throughout the gas chiller, for providing a uniformly spread second gas flow V2, preventing temperature stratification downstream. In case the gas chiller comprises a package providing the first gas stream to escape over a given surface, optionally a multitude of guides for guiding the second gas stream are used, which guides providing discharge points at the surface of the package. The discharge points are preferably equally distributed over the surface of the package. Optionally the guides may be equally spread or distributed over or across the intake surface of the gas intake system. Accordingly one or more embodiments of the present invention may have one or more of the following advantages.

Some embodiments of gas intake systems have the advantage that the filter load is reduced. A part of the particles to be filtered from the process gas to be compressed, e.g. ambient air, are trapped by the chilling fluid (e.g. water such as ice water). These particles, which are already trapped and evacuated from the gas stream, will not have to be filtered by the gas filter. Thus the load on the filter is reduced, providing longer standing time for the gas filter, thus requiring less maintenance interventions per time unit. Next to the advantage that at least a part of the gas contaminants are trapped by the chilling fluid, which is preferably water, in case ambient air is to be compressed, organic air polluting contaminants such as VOCs are filtered or trapped from the air as well, which avoids or reduces fouling of e.g. compressor blades and alike to a large extent. It was found that by dividing the intake gas in to a first gas stream being chilled using direct contact with the chilling fluid, and a second gas stream guided by means of a guide to the outflow side, which guide preventing the second gas stream to directly contact the chilling fluid and by merging the first gas stream and the second gas stream at the outflow side of the gas chiller, chilled gas near its saturation point may be provided. The gas of the first gas stream is chilled, and, because of the direct contact with the chilling fluid, its wet bulb temperature T1w and dry bulb temperature T1d will be almost identical, if not identical. The first gas stream will be near its saturation or optionally will provide saturated gas.

The gas of the second gas stream, which may be chilled to some extent as well, will be chilled to a less extent. The wet bulb temperature T2w of the second gas stream will be less than the dry bulb temperature T2d, although it was noticed that some condensation could be formed due to cold surface condensation effects, e.g. when the guide comprises tubes out of thermally conductive material, e.g. steel such as stainless steel, being chilled by chilling fluid. An appropriate selection of dimensions of the guide, may assure the provision of a second gas stream having a wet bulb temperature T2w being less than the dry bulb temperature T2d. It was found that the dry bulb temperature of the first gas stream T1d is less than the dry bulb temperature T2d of the second gas stream. By merging the first and second gas stream at the outflow side of the chiller for providing chilled gas, it was found that even if the first gas stream provides saturated gas, because of the merging of the two streams, the chilled gas after merging may be close to its saturation point, however the wet bulb temperature of the chilled gas will be less than the dry bulb temperature. Hence creation of fog or even droplets of fluid is avoided.

Thus it may be ensured that the chilled gas provided to the gas filter is not saturated or oversatu rated, while being cooled significantly as compared to the dry bulb temperature of the ambient air or gas taken in. Such saturation or oversaturation could cause the pollutants and contaminants trapped on the gas filter to interact with the water particles of dew or fog, which possible could be formed, such interaction causing gas pressure over the gas filter to rise quickly and possibly causing a pressure peak which is not allowable for the downwards located process elements.

The reduction of the filter load to the gas filter of a gas intake system may result in a longer standing time for the gas filter. Alternatively, in case the standing time of the gas filter is not a major issue, the dimensions of the gas filter may be reduced for a given gas volume to be filtered per time unit, or the gas volume to be filtered per time unit may be increased for a given gas filter dimension, in case the standing time of the gas filter may remain unchanged.

Some embodiments of a gas intake systems have the advantage that, especially in case of compression of ambient air and in case the air compression systems are operational in dry regions, the air provided to the compressor is already chilled, which increases the yield of the compressor and thus the yield of the system of which the air intake system is part of, e.g. a turbine unit, e.g. a gas turbine unit. According to some embodiments of gas intake systems according to the first aspect of the present invention, the flow of the first and second gas stream in the gas chiller may be controlled. This may be done during the designing of the gas intake system, where the different elements, and the dimensions of the different elements are designed and controlled e.g. by using design day conditions and process conditions in case of air intake systems. Also other aspects such as geographical and geological aspects may be taken in to account during designing of the gas intake system, more particular an air intake system. The design takes into account the "worst case" ambient conditions, for which conditions the chiller and the gas intake system is designed and dimensioned.

Optionally the gas intake system may be provided with a flow rate regulator, for adjusting the flow ratio of the first gas stream and the second gas stream. Preferably the flow of the second gas stream is adjusted. Such flow rate regulator may be a valve system, e.g. may make use of automated system such as a electromagnetically controlled valves, e.g. valve controlled with coils, or valves, such as rubber valves, controlled with compressed air, e.g. a rubber chamber in the pipe, swelling with the air injected via appropriate air provider. In case the second gas stream is guided via channels such as tubes, a redundant amount of channels or tubes may be installed as compared to the number of channels or tubes necessary to meet the worst case conditions. Some channels or tubes can be physically plugged at their downstream side, in order to prevent gas passing through the plugged channels or tubes. Plugging at the downstream side is preferred in order to prevent any droplets of condense created inside the channel or tube to be entrained. When necessary, some plugs could be removed in case the ambient or other conditions require this removal. According to some embodiments of the present invention, the guide preventing the second gas stream to directly contact the chilling fluid may be provided with one or a plurality of channels, e.g. one or a plurality of tubular guides, such as tubes.

The guide, e.g. each of the channels or optionally tubes, may be provided with one or more inertia separators, such as spin vanes. Each of the channels may comprise one or more spin vanes. The inertia separators, e.g. spin vanes, are optionally installed at the entrance or near the inflow side of the second guide, optionally at the entrances or near the inflow side of the one or the plurality of channels. Spin vanes cause the gas stream entering and flowing in the second guide to spin, hence to come into contact with the inner surface of the guide for condensing moisture, present in the gas stream, on the inner surface. The spin vanes may generate a vortex and force micro droplets in the gas to move outwards to the inner surface of the guide, e.g. tube, to which they will condense, forming larger droplets. Improved condensate elimination in the gas stream, and an improved mixing of the gas within the guide, may be obtained. As such, since a larger amount of moisture may be condensed from the second gas stream, the amount of moisture guided via the second guide to the downstream merging of the first and second gas stream, may further be reduced. The risk of oversatu rating a filter located downstream the intake may be further reduced. A similar effect is obtained using inertia separators other than spin vanes. This is in particular advantageous when the intake gas is air such as ambient air, which air is nearly or completely saturated, e.g. in foggy ambient.

The provision is in particular useful in case the chilling fluid used in the direct chiller is used at ambient temperature. A chilling fluid temperature less than ambient temperature is however favoured.

The provision of inertia separators, such as spin vanes, is particularly useful when high gas flows are used, e.g. gas flows in the guide of more than 3m/sec, even more than 5m/sec.Spin vanes may be installed also near the exit of the guide, such as near the exit of the tube. This may improve the mixing of the first and second gas stream when merging both gas streams, e.g. at the outflow side of the gas chiller. An improved mixing of the two gas streams may reduce or even avoid temperature stratification downstream the outflow side of the gas chiller.

As a safety measure, in order to avoid excessive moisture and/or oversaturated gas to pass the gas chiller and enter in downstream elements of the system (e.g. a gas intake system or more general, a gas or air compression system or a turbine unit, of which the gas chiller is part of) absorption media may be installed at the outflow side of the gas chiller. As an example, absorption media with open flute channels or a mist eliminator can be installed. Absorption media with open flute channels, the channels being unparallel to the gas flow direction, cause moisture to be caught by the absorption medium (and drained away by diffusion in the medium), while gas may flow through the medium and the channels.

Absorption media with open flute channels or a mist eliminator also may improve the mixing of the two gas streams at the outflow side of the gas chiller. If V1 represents the volume per time unit of chilled gas provided by the first gas stream and V2 is the volume per time unit of chilled gas provided by the second gas stream, the ratio V1/V2 may be adjusted in order to keep the dry bulb temperature of the chilled gas above but as close to the wet bulb temperature of the chilled gas.

Such adjustment may be done manually by means of the intervention of an operator. Optionally the gas intake system comprises sensors or instruments for measuring gas properties such as in case of air compression systems: relative or absolute humidity of the ambient air, wet or dry bulb temperature of the ambient air, ambient air pressure and alike, and air properties of the chilled air after the air chiller, such as pressure, wet and/or dry bulb temperature, dew point, humidity and alike. The gas intake system may comprise flow rate regulators for adjusting the gas flow rates of the first and second gas stream in function of the measured gas properties. The adjustment can be done automatically in this particular case. The adjustment is done in such a way that the temperature of the chilled gas at the outflow side of the gas chiller, i.e. of the chilled gas provided to the gas filter, is above the dew point of the chilled gas. More preferred, intake gas is chilled to provide chilled gas having a dry bulb temperature being larger the wet bulb temperature of the chilled gas. The dry bulb temperature may differ from the wet bulb temperature of the chilled gas according to a preset condition. In case the chilled gas is chilled air, the preset conditions for the difference between dry bulb temperature and wet bulb temperature of the chilled air may depend on the position of these temperatures on a psychometric diagram. The dry bulb temperature of the chilled air may be significantly less than the dry bulb temperature of even the wet bulb temperature of the ambient air.

This to create a safety margin for e.g. avoiding creation of fog or small liquid particles in the air provided to the air filter, which may interact with the trapped particles and contaminants on the air filter, in case the gas is air.

The guide for guiding the second gas stream may comprise a bypass for bypassing gas over the direct contact chiller of direct contact heat exchangers. The gas discharging from the guide is substantially identical to the gas being taken in by the guide.

Optionally the guide for guiding the second gas flow may be constructed as an indirect heat exchanger, cooling the second gas stream. The indirect heat exchanger may use the chilling fluid of the direct contact chiller as cooling fluid. Although the second gas stream is not cooled to its dewpoint temperature, in some situations, liquid condensation may occur at the cooling surfaces with which the second gas stream is in contact with, e.g. at the inner side of the tubes, in case the second gas stream is guided through a number of tubes, which are cooled at the outer side by a cooling fluid. The guide may therefore comprise outlets to evacuate possible condensate, resulting from the cooling of the second gas stream. At the outflow side of the gas chiller, the first gas stream and the second gas stream are merged for providing the chilled gas. Optionally, gas mixers or distributors are provided to ensure mixing of both gas streams, resulting in chilled gas discharged from the outflow side, having substantially uniform properties over the outflow side. In order to avoid stratification of the gas or air stream, which may cause vibrations and alike in the gas or air intake system and in the parts of the process system downwards the gas or air intake system, optionally a gas collector, gas mixers or gas distributors are provided to distribute the second gas stream as uniform as possible in the first gas stream. Therefore, in case the gas chiller comprises a package providing the first gas stream to escape over a given surface, optionally a multitude of guide for guiding the second gas stream are used, which guide providing discharge points at the surface of the package. The discharge points are preferably equally distributed over the surface of the package. In such a way, a maximum temperature difference within the gas stream of less than 2°C may be obtained, which maximum of temperature difference of some 2°C at the nose of the machinery is considered as a sufficiently uniform temperature distribution.

The chiller may further comprise a chilling fluid adjuster for adjusting the temperature and or the volume per time unit of chilling fluid provided to the chiller. The adjustment of the temperature of the chilling fluid, and/or the tuning or adjustment of the amount of chilling water provided per time unit, may be used to control the dry bulb temperature and the wet bulb temperature of the chilled gas.

Any of the gas intake systems according to embodiments of the first aspect of the present invention, or any of the gas chillers according to embodiments of the second aspect of the present invention, may be used in applying the method for taking in gas according to embodiments of this third aspect of the present invention. According to a fourth aspect of the present invention, a method to modify an existing gas intake system is provided, resulting in a modified gas intake system having the advantages as set out above. The existing gas intake system comprising

• a gas intake for taking in gas,

• the intake gas filter located downstream the gas intake.

The method according to the fourth aspect of the present invention comprises the step of • providing a gas chiller for chilling intake gas, the gas chiller having an inflow side for receiving intake gas and an outflow side for providing chilled gas to the gas filter, the gas chiller comprises a gas distributor to divide the intake gas in a first gas stream and a second gas stream, the gas chiller has a direct contact chiller for chilling the first gas stream by directly contacting of the first gas stream with a chilling fluid, the gas chiller has a guide for guiding the second gas stream to the outflow side, the guide preventing the second gas stream to directly contact the chilling fluid, the first gas stream and the second gas stream merging at the outflow side of the gas chiller for providing the chilled gas at the outflow side of the gas chiller, the chiller being adapted to provide chilled gas having a dry bulb temperature being larger than the wet bulb temperature of the chilled gas, and

• coupling the inflow side of the gas chiller to the gas intake and coupling the outflow side of the gas chiller to the gas filter.

According to a fifth aspect of the present invention, a method for constructing of a gas intake system is provided. The method of construction of a gas intake system comprises the steps of

• providing a gas intake for taking in gas,

• providing the intake gas filter located downstream the gas intake, • providing a gas chiller for chilling intake gas, the gas chiller having an inflow side for receiving intake gas and an outflow side for providing chilled gas, the gas chiller comprises a distributor to divide the intake gas in a first gas stream and a second gas stream, the gas chiller has a direct contact chiller for chilling the first gas stream by directly contacting of the first gas stream with a chilling fluid, the gas chiller has a guide for guiding the second gas stream to the outflow side, the guide preventing the second gas stream to directly contact the chilling fluid, the first gas stream and the second gas stream merging at the outflow side of the gas chiller for providing the chilled gas at the outflow side of the gas chiller, the chiller being adapted to provide chilled gas having a dry bulb temperature being larger than the wet bulb temperature of the chilled gas, and

Some embodiments of the method, where the gas intake system is an air intake system for compressing ambient air being intake air of the air intake system, the air intake systems are especially advantageous for use in world regions where dry and hot ambient conditions occur frequently. In such regions, the dry ambient air is loaded with numerous dry particles and liquid, amorphous or gaseous contaminants, which are to be removed from the air provided to the compressor of the air compression system. The use of methods and devices according to the present invention, wherein the gas is air such as ambient air, has the advantage that the air provided to the compressor is reduced in temperature, which increases the yield of the air compression, and of the system of which the compression system is part. If the air chiller is provided upstream the air filter, it also has the advantage that a part of the dry particles and contaminants in the ambient air is already knocked down and removed from the air stream prior to providing the air stream to the air filter, resulting in longer standing periods of the air filter, or a reduction of the load of the air filter in the air compression system. The methods and devices according to the present invention further have the advantage that the provision of saturated or over-saturated chilled air to the air filter is minimized or even avoided.

Some embodiments of the method has the advantage that existing and operational gas intake systems can be upgraded, i.e. provided with a gas intake system according to the first aspect of the present invention, without the need of dismantling the already installed gas filters and gas compressor. It may be placed upstream, or even in front of the existing gas filters, and only the existing gas intake is to be displaced.

Any of the gas chillers according to embodiments of the second aspect of the present invention may be applied in the methods to modify or construct a gas intake system according to embodiments of the fourth or fifth aspect of the present invention.

Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate and not merely as explicitly set out in the claims.

Although there has been constant improvement, change and evolution of devices in this field, the present concepts are believed to represent substantial new and novel improvements, including departures from prior practices, resulting in the provision of more efficient, stable and reliable devices of this nature.

The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings. Brief description of the drawings

Fig. 1 is a schematically view of a gas intake system more particular an air intake system, according to the first aspect of the present invention.

Fig. 2 is more detailed schematically view of the gas chiller of the gas intake system of Fig. 1.

Fig. 3 is a detail of the packing of the direct contact chiller being part of the gas chiller of the gas intake system of Fig. 1.

In the different figures, the same reference signs refer to the same or analogous elements.

Description of illustrative embodiments

The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein. Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.

It is to be noticed that the term "comprising", used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

Similarly, it is to be noticed that the term "coupled", also used in the claims, should not be interpreted as being restricted to direct connections only. The terms "coupled" and "connected", along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. Thus, the scope of the expression "a device A coupled to a device B" should not be limited to devices or systems wherein an output of device A is directly connected to an input of device B. It means that there exists a path between an output of A and an input of B which may be a path including other devices or means. "Coupled" may mean that two or more elements are either in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other. Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

Similarly it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

Furthermore, some of the embodiments are described herein as a method or combination of elements of a method that can be implemented by a processor of a computer system or by other means of carrying out the function. Thus, a processor with the necessary instructions for carrying out such a method or element of a method forms a means for carrying out the method or element of a method. Furthermore, an element described herein of an apparatus embodiment is an example of a means for carrying out the function performed by the element for the purpose of carrying out the invention.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description. Features disclosed in relation to one of the embodiments according to one of the aspects of the present invention may be applied in other embodiments according to the same or a different aspect of the present invention. The following terms are provided solely to aid in the understanding of the invention.

The term "flow" is to be understood as the volume of a fluid per time unit provided. For gas-liquid system such as an air-water system, following definitions hold:

• The dry bulb temperature of the gas such as air is the temperature of a gas indicated by a thermometer. • The wet bulb temperature of a gas such as air is the temperature at which a liquid or liquid water, by evaporation into the gas such as air, can bring the gas such as air to saturation adiabatically at the same temperature. The wet bulb temperature is the temperature indicated by a wet bulb psychometer. • The dewpoint temperature is the temperature at which the condensation of the liquid vapour such as water vapour in a space begins for a given state of vapour concentration or humidity and pressure as the temperature of the vapour is reduced. The temperature corresponds to saturation (100 percent relative humidity) for a given absolute humidity at constant pressure.

• Saturated gas or air means gas or air in which no additional liquid vapour or moisture can be added to the gas-liquid, e.g. air-water vapour mixture at given pressure and temperature.

• The saturation temperature is the temperature at which no further liquid vapour such as moisture can be added to the gas-liquid, e.g. air-water vapour mixture. The saturation temperature equals the dew point temperature.

• The relative vapour concentration or the relative humidity is the ratio of the quantity of liquid vapour or water vapour present in the gas or air compared to the quantity of liquid vapour or water vapour present in saturated gas or air at the same temperature and barometric pressure.

In the light of the present invention, the above definitions are defined to the more general gas-liquid system in a similar way to that for an air-water system.

The invention will now be described by a detailed description of several embodiments of the invention. It is clear that other embodiments of the invention can be configured according to the knowledge of persons skilled in the art without departing from the true spirit or technical teaching of the invention, the invention being limited only by the terms of the appended claims.

A gas intake system 100 according to the first aspect of the present inventing is shown schematically in Fig. 1. The gas intake system 100 is an air intake system, comprising an air intake 110 for taking in air 1000 from ambient.

It comprises a set of sheds 111 to prevent entrance of rain and snow in the air intake.

The air intake system 100 may be coupled to, and provided for providing intake air to an air compressor 1400 located downstream the air intake system 100. The air intake system 100 comprises an air filter 130 located downstream the air intake 110 and before, i.e. upstream the air compressor 1400.

The air chiller 120 has an inflow side 121 for receiving air 1000 and an outflow side 122 for providing chilled air 2000 to the air filter 130. The air chiller 120 is adapted to chill ambient air 1000 thereby providing chilled air 2000 with a temperature above its dew point, i.e. air provided in a condition where the dry bulb temperature is above the wet bulb temperature, and the dry bulb temperature of the chilled air being less than the dry bulb temperature of the ambient air.

The ambient air 1000 is divided in a first air stream 210 and a second air stream 220.

The air chiller 120 has a direct contact chiller 300 for chilling the first air stream 210 by directly contacting of the first air stream 210 with a chilling fluid 310. As will be described more in detail by means of Fig. 3, the direct contact chiller 300 or direct contact heat exchanger may comprise a packing 301 which allows chilling fluid 310 to make direct contact with the first air stream 210. The chilling fluid, such as ice or cooled water, is provided at the topside of the packing 301 using appropriate feeding pipes 303. The chilling fluid 310 seeps through the packing 301 downwards where it is gathered in a reservoir 302. Via fluid guiding tubes 304 the fluid is provided to a fluid filter unit 305 for removal of particles and contaminants, which were filtered from the first air stream 210 in the direct contact heat chiller 300. The chilling fluid 310 is than stored and cooled using a storage system 306 from which the chilling fluid is provided back to a cooler 307 and an adjustable valve 308 to the feeding pipes for being provided to the packing 301.

During chilling of the first air stream in the direct contact chiller 300, the first air stream is reduced in temperature and humidified optionally up to its saturation point. It is even possible to cool the first air stream below its dewpoint, so water is extracted from the first air stream. This condensate flows down together with the chilling fluid 310. The first air stream leaving the direct contact chiller 300 at the outflow side 122 is thus cold and optionally at its saturation point.

The air chiller 120 has a guide 400 for guiding the second air stream 220 to the outflow side 122. The guide 400 prevents the second air stream 220 to directly contact the chilling fluid 310. As shown in Fig. 1 , the guide 400 is provided in this embodiment as an indirect heat exchanger, comprising a number of tubes 410. The second air stream 220 flows through the tubes 410 from the inflow side 121 to the outflow side 122. The outer wall of the tubes 410 is brought into contact with the chilling fluid 310. Thermal energy, provided by the second air stream 122 at the inner side of the tubes 410, is conducted to the chilling fluid 310 through the walls of the tubes 410. This may cause a temperature reduction of the second air stream 122. It was noticed that by controlling the flow and/or temperature of the first and second air stream, the second air stream may be cooled to a temperature well above its dewpoint. In spite of this, some water may condensate in the tubes 410. As will be explained in more detail in Fig. 2, the tubes may be provided with outlets to evacuate the condensate from its internal volume.

In order to increase the contact between the second air stream and the inner side of the tube 410, inertia separators, such as in this embodiment spin vanes 430, may be provided near the inflow side 421 of the tube 410.

Due to the spinning of the air stream 220 in the tube 410, created by the spin vanes 430, the contact of air of the air stream with the cooled tubular wall will be intensified. This will cause the second air stream 220 to cool and optionally to condensate to a larger extent inside the tubes 410. Optionally (not shown in figure 1 ) spin vanes may be installed in the tubes 410 near the outlet sides 422 or discharge ends 420 of the tubes. This improves the mixing of the first air stream 210 and second air stream 220 at the outflow side 122, where both air streams merge. As a safety measure, in order to avoid excessive moisture and/or oversaturated gas to pass the gas chiller and enter in downstream elements of the system, e.g. in case of failure of any of the elements of the gas chiller, a mist eliminator or absorption medium, e.g. absorption media with open flute channels optionally unparallel to the gas flow, may be installed at the outflow side of the gas chiller. As an example, a mist eliminator can be installed.

The first air stream 210 and the second air stream 220 are merged at the outflow side of the air chiller for providing the chilled air 2000 at the outflow side 122 of the air chiller 120. The merging of the air streams has the effect that the temperature of the first air stream is raised. This causes the dry bulb temperature of the first air stream to become above the wet bulb temperature of the first air stream, even in case the first air stream was saturated prior to merging. The humidity from the second air stream may influence the humidity of the chilled air to some extent, but is not sufficient to bring the wet and dry bulb temperature of the merged air streams, thus of the chilled air, to become equal. The dry bulb temperature will remain more than the wet bulb temperature. Hence saturation of the chilled air 2000 is avoided. The controlled flows of first and second air stream cause the chilled air 2000 to have a temperature above its dew point, hence reducing or even avoiding fogging at the outflow side 122.

A more detailed schematically view of the air chiller 120 is shown in Fig. 2. A detail of the packing 301 of the direct contact chiller 300, provided with tubes 410 of the guide 400 is shown in Fig. 3.

The air chiller 120 comprises a number of consecutive package sections 323, 324 and 325. Each package section 323, 324 and 325 comprises a packing 301 which forms the mechanical matrix of the direct contact chiller 300. As better shown in Fig. 3, the packing 301 may cellular blocks or honeycomb like structures, e.g. COLDFREE TR40V blocks of Hamon&Cie (Belgium), consisting a PVC thermoformed perforated sheets to form an assembly of more or less square sections standing on a side of the square section. The open end of the channels or hollow sections 312 are facing the air flow and give very low delta p. Chilling fluid 310, such as chilling water, is provided at the top 313 of the package 301 The chilling fluid, e.g. chilling water, drips downwards, through the perforations of the perforated sheets, making a turbulent water layer along each corrugation of the sheet, the first air stream 210 is cooled or chilled by passing through each hollow section 312.

A water distribution system made of a manifold and a series of feeding pipes 303 at a given distance is connected to the cold side of the chiller circuit, providing cold chilling fluid 310. The last package section 325 of the packing optionally remains without chilling fluid feeding to insure no water droplets are entrained downstream. Alternatively, in case the last package section 325 is provided with chilling fluid, a droplet catcher section (not shown in Fig. 2) to act as a safety for any water leaks and chilling water entrained with the first air stream may be provided, which can be the standard air intake hood protection including the droplet catcher and flow equalizers and alike.

The chilling fluid circuit may further comprise a fluid filter unit 305 and a cooling and storage unit 306 comprising fluid cooling unit or fluid cooler and water tank, optionally in multiple sections, connected to the return line of the air cooler by means of pumps and water level control. An overflow system 307 to feed out the produced condensed water, which is entrained by the chilling fluid 310, may be provided.

The consecutive sections may be provided as a modular casing divided, in several sections on the height, determined by the acceptable delta p gradient downstream, the in and out chilling fluid temperature, the flow velocities of the first and second air stream and other process and environment parameters.

Turning now to the guide 400, the guide is provided as an indirect heat exchanger comprising a number of tubes 410 which may be provided through the consecutive package sections 323, 324 and 325 of the direct contact chiller. A given quantity of tubes 410 with given dimension are installed depending upon the delta p across the packing and across the whole air chiller 120, i.e. between inflow side 121 and outflow side 122 and the desired delta t over the air chiller 120 and the delta t over the indirect heat exchanger 400 required for the application. The discharging ends or points 420 of the tubes 410 are equally distributed over the discharging surface 320 of the package 301 for providing a uniform distribution of the second gas stream 220 in the first gas stream 210.

During designing of the air intake system 100, and taking the ambient conditions of reference or designing days into account for the location here the air intake system 100 is to be operational, the quantity of tubes 410, the tube dimensions, the tube materials and alike may be chosen to provide in a controlled way the flow or volume per time unit of the second air stream 220. As the flow/ delta p characteristic of the tube 410 is known, it is possible to determine the quantity of the second air stream 220 needed to prevent any saturation downstream at the outflow side 122 of the air chiller 120 after merging the first and second air stream 210, 220, taking a desired safety margin into account. The tubes 410 may be provided from copper, aluminum or stainless steel. However in case the choice of such thermally conductive materials would provide the creation of excessive condense of the second air stream, polymer materials such as PVC may be used. In case it is preferred to have the flows or volumes per time unit of first and second air stream adjustable, the air chiller 120 may comprise a flow rate regulator 500 for adjusting the flow ratio of the first air stream and the second air stream. Optionally the air chiller 120 may comprises instruments 501 for measuring ambient air properties such as relative or absolute humidity of the ambient air, wet or dry bulb temperature of the ambient air, ambient air pressure and alike, and instruments 502 to measure air properties of the chilled air after the air chiller, such as pressure, wet and/or dry bulb temperature, dew point, humidity and alike. The air intake system may comprise a flow rate regulator 503 for adjusting the flow ratio of the first air stream and the second air stream or the air flow rates of the first and second air stream in function of the measured air properties, in the process and/or ambient. The adjustment can be done automatically in this particular case, which adjustment can be controlled by a controller 503, adjusting the flow rate regulator 500 for adjusting the flow rates in function of the measured air properties by instruments 501 and 502. The adjustment can be controlled by a controller 503 in function of the wet bulb temperature and the dry bulb temperature. The chiller may comprise a chilling fluid regulator 504 for adjusting the temperature and or the flow or volume per time unit of chilling fluid provided to the chiller, i.e. for controlling the cooler 309 or the valve 308.

A bellmouth or tapered or funnelling shape at the tube inlet section can reduce the inlet loss of each tube 410. The tubes 410 may be made such that any condensation within the tube is eliminated. This may be obtained by providing the tubes 410 in several consecutive tube sections 411 , 412 and 413. Each tube section may extend through one of the package sections 323, 324 and 325 of the direct contact chiller 300. Between two consecutive tube sections 411 and 412 or 412 and 413, slits 414 extending in the in the void spaces 319 between two consecutive package sections 323, 324 and 325 of the direct contact chiller 300. Alternatively, not shown in Fig. 2, each slit may extend in one of the package sections. The condensed water in a tube section 411 , 412 and 413 of a tube may be evacuated via small slits 414 in between the tube sections or in the package, or may be evacuated by dripping out of the last tube section 413 at the outflow side 122 of the air chiller 100.

In order to increase the contact between the second air stream and the inner side of the tube 410, inertia separators, such as in this embodiment spin vanes 430, may be provided near the inflow side 421 of the tube 410. In case the tube comprises consecutive tube sections, spin vanes may be provided at the inflow side of some or each tube section.

Due to the spinning of the second air stream 220 in the tube 410, or tube sections 41 1 , 412 and/or 413, created by the spin vanes 430, the contact of air of the second air stream 220 with the cooled tubular wall will be intensified. This will cause the second air stream 220 to cool more and earlier, hence may cause water to condensate to a larger extent and earlier, i.e. closer to the inflow side 411 of the tube 410. Optionally spin vanes 431 may be installed in the tubes 410 near the outlet sides 422 or discharge ends 420 of the tubes 410, in particular the outlet sides 422 or discharge ends 420 of the last tube sections 413 of the tubes 410.

This improves the mixing of the first air stream 210 and second air streams 220 at the outflow side 122, where both air streams merge.

As a safety measure, in order to avoid excessive moisture and/or oversaturated gas to pass the gas chiller and enter in downstream elements of the system, e.g. in case of failure of any of the elements of the gas chiller, a mist eliminator or absorption media, e.g. absorption media with open flute channels optionally unparallel to the gas flow, may be installed at the outflow side of the gas chiller. As an example, or a mist eliminator can be installed.

It is advantageous to provide a gas intake system according to the first aspect of the present invention, as the chilled gas is sufficiently dry to avoid moistening of the gas filter downstream, thus avoiding the contamination and particles trapped by the gas filter to clog due to moistening. For some embodiments, e.g. when using a direct contact chiller for chilling at least a part of the intake gas, the part of the intake gas directly contacting the chilling fluid will partially be cleaned, hence the amount of contaminants and particles guided to the gas filter will at least partially be reduced. Especially in case the gas intake system is an air intake system for compression of ambient air, also VOC may be removed from the air by means of the direct contact chiller. This has the advantage that the amount of VOCs that may contaminate downstream parts of the unit of which the compression system is part of, is reduced.

It is well understood by the skilled person that the air intake system as set out using Fig. 1 , Fig. 2 and Fig. 3 may be used as a gas intake system in industrial processes, whereby only slight modifications are necessary to compress process gas other than air, in stead of compression of ambient air. It is also understood that the air intake system may be used to compress air other than ambient air.

Turning to the second aspect of the present invention, it is understood that the gas intake system as shown in Fig. 1 , Fig. 2 and Fig. 3 is used to provide e.g. compressed air to e.g. a turbine unit such as a gas turbine, or an air conditioning system. The use of the gas intake system as shown in Fig. 1 , Fig. 2 and Fig. 3 has the advantage that the chilling fluid removes a part of the contamination in the first air stream, hence the loading on the gas filter downstream the air chiller is reduced. As moisture creation in the chilled gas, such as chilled air, is avoided prior to the gas filter, the filter will not be moistened and the filtered contaminants on the gas filter will be prevented from reacting or clogging due to the moistening.

Turning to the third aspect of the present invention, reduction of the temperature of the gas provided to e.g. a gas compressor by means of a gas intake system according to the first subject of the present invention can easily be obtained, especially in case the gas intake system is an installed air intake system such as the air intake system of an existing turbine unit. The advantage of the gas intake system is that the gas chiller, especially the air chiller of an air intake system, can be easily mounted in the existing process lines.

The reduction of the temperature of the gas provided to e.g. the gas compressor only requires to dismantle the existing gas intake system, in particular the air intake of an air intake system, and the addition of the gas chiller, in particular the air chiller of the air intake system according to some embodiments of the present invention. After installation of the gas chiller, the gas intake needs to be provided or coupled at the inflow side of the gas chiller. In case the gas chiller, in particular the air chiller comprises a direct contact chiller for chilling at first part of the gas or air to be chilled, the method according to the third aspect of the present invention has the additional advantage of reducing the load on the gas filter or air filet installed after the gas or air chiller.

Other arrangements for accomplishing the objectives of the gas intake system and a method for taking in gas in a gas intake system, a method for modifying an existing gas intake system and a method for constructing a gas intake system, embodying the invention, will be obvious for those skilled in the art. It is understood that an indirect gas chiller, e.g. chilling coils being provided with chilling fluid at one side of the tubular coil and gas to be chilled at the other, preferably the outer side of the tubular chilling coil, the indirect gas chiller provided for chilling intake gas and being adapted to provide chilled gas at a temperature above its dew point, may be used as an element to provide an embodiment of the gas intake systems according to the first aspect of the present invention. It is understood as well that the use of an indirect gas chiller for chilling the first gas stream in case a gas chiller comprising a gas distributor to divide the intake gas in a first gas stream and a second gas stream may be used as well to provide an embodiment of the gas intake systems according to the first aspect of the present invention.

It is to be understood that although preferred embodiments, specific constructions and configurations, as well as materials, have been discussed herein for devices according to the present invention, various changes or modifications in form and detail may be made without departing from the scope and spirit of this invention. Steps may be added or deleted to methods described within the scope of the present invention.

Claims

1.- A gas intake system comprising

• a gas intake for taking in gas, • a gas filter located downstream of the gas intake and

• a gas chiller for chilling intake gas, the gas chiller having an inflow side for receiving intake gas and an outflow side for providing chilled gas to the gas filter, the gas chiller for chilling intake gas being adapted to provide chilled gas having a dry bulb temperature and a wet bulb temperature, the dry bulb temperature being larger than the wet bulb temperature of the chilled gas, wherein the gas chiller comprises a gas distributor to divide the intake gas in a first gas stream and a second gas stream, the gas chiller has a direct contact chiller for chilling the first gas stream by directly contacting of the first gas stream with a chilling fluid, the gas chiller has a guide for guiding the second gas stream to the outflow side, the guide preventing the second gas stream to directly contact the chilling fluid, the first gas stream and the second gas stream merging at the outflow side of the gas chiller for providing the chilled gas at the outflow side of the gas chiller.

2.- A gas intake system according to claim 1 , wherein the gas chiller for chilling intake gas is adapted to adjust the dry bulb temperature and/or the wet bulb temperature for providing the dry bulb temperature being larger than the wet bulb temperature of the chilled gas

3.- A gas intake system according to any one of the claims 1 to 2, wherein

V1 is the flow of chilled gas provided by the first gas stream, V2 is the flow of chilled gas provided by the second gas stream, the ratio V1/V2 is adapted to provide the dry bulb temperature being larger than the wet bulb temperature of the chilled gas.

4.- A gas intake system according to claim 3, wherein the gas chiller further comprises a flow rate regulator for adjusting the flow ratio of the first gas stream and the second gas stream.

5.- A gas intake system according to claim 4, wherein the flow rate regulator is adapted to adjust the flow ratio of the first gas stream and the second gas stream in function of the dry bulb temperature and/or the wet bulb temperature of the chilled gas at the outflow side of the gas chiller.

6.- A gas intake system according to any one of the claims 1 to 5, wherein the guide is an indirect heat exchanger for chilling the second gas stream.

7.- A gas intake system according to claim 6, wherein the cooling fluid of the indirect heat exchanger is the chilling fluid of the direct contact chiller.

8.- A gas intake system according to any one of the claims 6 to 7, wherein the chiller comprises a chilling fluid regulator for adjusting the temperature and or the volume per time unit of chilling fluid provided to the chiller.

9.- A gas intake system as in any one of the claims 1 to 8, wherein the gas intake system is an air intake system.

10.- An air compression system comprising an air intake system as in claim 9.

11.- A turbine unit comprising an gas intake system as in any one of the claims 1 to 9.

12.- A method for taking in gas in a gas intake system, the gas intake system comprising

• a gas intake for taking in gas;

• the gas filter located downstream the gas intake; • a gas chiller between gas intake and gas filter, which gas chiller is adapted to divide the intake gas into a first gas stream and a second gas stream, the method comprising the steps of • dividing the intake gas into a first gas stream and a second gas stream,

• chilling the first gas stream by directly contacting of the first gas stream with the chilling fluid, guiding the second gas stream to the outflow side while preventing the second gas stream to contact the chilling fluid directly;

13.- A method for taking in gas in a gas intake system according to claim 12, wherein means are provided for avoiding temperature stratification downstream the gas intake system.

14.- A method for modifying an existing gas intake system, the existing gas intake system comprising

• a gas intake for taking in gas,

• the intake gas filter located downstream the gas intake and the gas compressor, the method comprises the step of

• providing a gas chiller for chilling intake gas, the gas chiller having an inflow side for receiving intake gas and an outflow side for providing chilled gas to the gas filter, the gas chiller comprises a gas distributor to divide the intake gas in a first gas stream and a second gas stream, the gas chiller has a direct contact chiller for chilling the first gas stream by directly contacting of the first gas stream with a chilling fluid, the gas chiller has a guide for guiding the second gas stream to the outflow side, the guide preventing the second gas stream to directly contact the chilling fluid, the first gas stream and the second gas stream merging at the outflow side of the gas chiller for providing the chilled gas at the outflow side of the gas chiller, the chiller being adapted to provide chilled gas having a dry bulb temperature being larger than the wet bulb temperature of the chilled gas, and

15.- A method for constructing a gas intake system, comprising the steps of

• providing a gas intake for taking in gas,

• providing the intake gas filter located downstream the gas intake,

• providing a gas chiller for chilling intake gas, the gas chiller having an inflow side for receiving intake gas from the gas intake and an outflow side for providing chilled gas to the intake gas filter, the gas chiller comprises a gas distributor to divide the intake gas in a first gas stream and a second gas stream, the gas chiller has a direct contact chiller for chilling the first gas stream by directly contacting of the first gas stream with a chilling fluid, the gas chiller has a guide for guiding the second gas stream to the outflow side, the guide preventing the second gas stream to directly contact the chilling fluid, the first gas stream and the second gas stream merging at the outflow side of the gas chiller for providing the chilled gas at the outflow side of the gas chiller, the chiller being adapted to provide chilled gas having a dry bulb temperature being larger than the wet bulb temperature of the chilled gas, and

16.- A gas chiller having an inflow side for receiving intake gas and an outflow side for providing chilled gas, the gas chiller comprises a gas distributor to divide the intake gas in a first gas stream and a second gas stream, the gas chiller comprises a gas collector for merging the first gas stream and the second gas stream at the outflow side of the gas chiller, the gas chiller comprises

• a direct contact chiller for chilling the first gas stream by directly contacting of the first gas stream with a chilling fluid, the direct contact chiller comprises a package and a liquid provider for providing chilling liquid to the package, the package providing a plurality of hollow sections for guiding the first gas stream from the inflow side to the outflow side while allowing direct contact between the chilling fluid and the first gas stream, • a guide for guiding the second gas stream to the outflow side, the guide preventing the second gas stream to directly contact the chilling fluid, the guide comprising at least one tube extending through one of the hollow sections of the direct contact chiller.

17.- A gas chiller according to claim 16, wherein the gas chiller comprises a means for avoiding temperature stratification downstream the gas intake system

18.- A gas chiller according to any one of the claims 16 to 17, wherein the package of the direct contact chiller comprises at least two package sections, mounted consecutively in flow direction of the first gas stream.

19.- A gas chiller according to claim 18, wherein a void space is provided between two consecutive package sections.

20.- A gas chiller according to any one of the claims 16 to 19, wherein the at least one tube comprises two consecutive tube sections.

21.- A gas chiller according to any one of the claims 16 to 20, wherein the at least one tube comprises two consecutive tube sections, between two consecutive tube sections a slits is for removing condense from the inner volume of the tube sections to the package.

22.- A gas chiller according to any one of the claims 16 to 21 , wherein the guide comprising a multitude of tubes, the tubes being substantially equally distributed throughout the gas chiller for preventing temperature stratification downstream.

23.- A gas chiller as in any one of the claims 16 to 22, the gas chiller being an air chiller for chilling ambient air.

24.- An air intake system comprising an air chiller as in claim 23

25.- A turbine unit comprising a gas chiller as in any one of the claims 15 to 23.