CN1419082A - Apparatus and method for treating cooking fume, peculiar small gas and other harmful substance - Google Patents
Apparatus and method for treating cooking fume, peculiar small gas and other harmful substance Download PDFInfo
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- CN1419082A CN1419082A CN 02159541 CN02159541A CN1419082A CN 1419082 A CN1419082 A CN 1419082A CN 02159541 CN02159541 CN 02159541 CN 02159541 A CN02159541 A CN 02159541A CN 1419082 A CN1419082 A CN 1419082A
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Abstract
The present invention relates to an equipment fo r treating cooking fume, abrnormal smell and other farmful substances and its method. One end of ventilation pipe is communicated with extractor fan near to the cooking stove, its another end is connected with at least one ring reaction chamber with hollow cavity, and the exterior of cooking stove burner is covered with said reaction chamber with at least one outlet. In the interior of the reaction chamber the adsorbing agent, catalyst and filtering screen can be placed. The extractor fan can be used for collecting fume, air, abnormal smell gas and other harmful substances mixture, and the collected mixture is passed through the ventilation pipe, preheated and fed into the reaction chamber, the harmful substance can be oxidated into carbon dioxide and water, or firstly decomposed, then oxidated, and can be discharged into exterior or collected for make secondary treatment.
Description
Technical Field
The invention relates to a device and a method for removing kitchen oil fume, peculiar smell gas and other harmful substances.
Background
Most activities of humans are performed indoors. Contamination of the indoor environment can lead to a variety of diseases. Cooking fume and pungent odor are one of the main indoor environmental pollution sources. When the cooking temperature is higher than 130 ℃, oil smoke is generated from the edible oil and fat, which can cause damage to the respiratory and circulatory systems of people. Especially when the temperature reaches 230-280 ℃, some carcinogenic substances can be generated in the oil smoke. According to the analysis of Taiwan health administration, the lung cancer rate of Taiwan housewives is high, and the main reason is that the Taiwan housewives are in the environment polluted by cooking oil smoke for a long time. On the other hand, irritant gases generated during cooking, such as irritating odor generated during the dry frying of hot pepper, can also damage the respiratory system of human. In addition, some of the hazardous materials come from the cooking heat source. Such as smoke generated from charcoal and flying charcoal dust when barbecued; carbon monoxide is generated from oil-fired ranges, gas-fired ranges or various ranges using coal as fuel due to insufficient combustion. These substances are even more harmful to humans.
In order to remove oil smoke and odor, a conventional method is to collect the oil smoke and odor using a suction fan installed above a cooking range, filter the oil smoke and odor slightly, and then discharge the filtered oil smoke to the outdoor atmosphere or a sewer. This approach has a number of disadvantages.
First, a piping system leading to the outside of the room must be designed and installed. Thereby increasing the house building cost. If the purchased house does not have such a system, the purchaser will spend money and time to rebuild. If a house is rented, the house owner is not allowed to have oil smoke pollution and is not prepared for reconstruction, and the house renter only needs to change the eating habits and does not eat dishes any more.
Secondly, the oil smoke and the peculiar smell discharged to the outdoor cause pollution to the atmosphere or a sewer and influence the life of neighbors.
Third, fumes and odors are not completely extracted from the room. In order to increase the suction efficiency, the fan power must be increased, which in turn may generate more noise.
Fourth, the blower needs to be cleaned by a professional at regular intervals. Otherwise, the oil is condensed and the motor may be burnt. Because the inside of the exhaust duct is difficult to clean, a large amount of oil stains are inevitably accumulated, and potential safety hazards are caused.
Fifthly, an oil layer is accumulated on the inner wall of the fan cover of the exhaust fan, oil dripping and oil leakage are difficult to avoid, frequent cleaning is needed, and the patient is restless and cannot feel well.
Finally, odorous gases are more difficult to remove than oil smoke. With modern open kitchen designs, it is a difficult problem how to avoid odors entering other rooms.
To solve these problems, many improvements have been made. Including the methods of the various patents. Most commonly, the fumes are absorbed by water mist, water curtains or dense water droplets, and the treated air stream is then discharged to the outside (see US5359990, US4929258, US5601072, US 5180405). The disadvantages of this kind of method are that the equipment structure is complex, the effect is limited, the cost ishigh, it is not suitable for household and it is easy to cause secondary pollution. Other physical treatment methods include a method of rapidly cooling the gas flow containing the oil smoke by using a refrigeration technology to separate oil drops (for example, U.S. Pat. No. 5,5280709), a method of separating oil drops by using an aerodynamic principle (U.S. Pat. No. 5754742), a method of improving an oil smoke filter screen (U.S. Pat. No. 5,0365), and the like. These methods are either too complicated or have a very limited smoke removal effect. The methods of removing soot using chemical principles have not been so many. French patent 2106935 proposes heating the oily fume stream with an electric heating element to oxidize and decompose the oil molecules before being discharged to the outside. The biggest problem of the method is that the high electricity cost is difficult to be accepted by ordinary families. The US2224945 patent suggests another type of electric heating method which is not of great practical value. Other methods for improving the structure of the range hood (such as Japanese patent Sho 61-24935, US5842464, US5027790 and the like) do not have substantial breakthrough, cannot solve the existing fundamental problem, and a new idea needs to be found.
Disclosure of Invention
The invention aims to solve the problem of removing kitchen oil fume, peculiar smell gas and other harmful substances.
The invention relates to a device for treating cooking oil fume, peculiar smell gas and other harmful substances, wherein one end of a ventilating duct is communicated with a suction fan near a cooking stove, and the device is characterized in that: the other end of the ventilation pipeline is connected with at least one annular reaction chamber with a cavity, the reaction chamber is sleeved on the periphery of the burner of the cooking stove and is provided with at least one outlet.
The reaction chamber is internally provided with an adsorbent which can adsorb partial reaction products and partial oil smoke, peculiar smell gas and other harmful substances which are not oxidized or decomposed.
The reaction chamber is internally provided with a catalyst which can reduce the temperature required by the oxidation or decomposition of oil smoke, odor gas and other harmful substances.
The reaction chamber is internally provided with a filter screen which can prevent solid particles from escaping from the reaction chamber.
A preheating device for heating and cooking oil fume, peculiar smell gas and other harmful substances is arranged between the ventilating pipe and the reaction chamber or in the ventilating pipe.
The outlet of the reaction chamber is connected with a circulating guide plate or an additional pipeline communicated with the outdoor atmosphere.
The method for treating cooking oil fume, peculiar smell gas and other harmful substances is characterized in that: the exhaust fan is communicated with at least one ventilation pipeline and then enters at least one reaction chamber, in the reaction chamber, oil smoke, peculiar smell gas and other harmful substances in the mixture are directly oxidized into carbon dioxide and water by oxygen contained in the mixture, or are firstly decomposed into intermediate products, the intermediate products are oxidized into the carbon dioxide and the water, all the reaction products and the substances which do not participate in the reaction and do not participate in the reaction in the mixture are discharged from an outlet of the reaction chamber and enter the air, a high temperature level is maintained in the reaction chamber, and the heat energy required for maintaining the temperature in thereaction chamber comes from a heat source of a cooking stove.
The temperature in the reaction chamber is not lower than 100-200 ℃.
A preheating device for heating and cooking oil fume, peculiar smell gas and other harmful substances is arranged between the ventilating pipe and the reaction chamber or in the ventilating pipe, and the heat energy required by the device is from an additional heat source of the non-cooking stove.
After the mixture containing the oil fume, the peculiar smell gas and other harmful substances is processed in the reaction chamber, reaction products and substances which do not participate in reaction and do not participate in reaction in the mixture are discharged from an outlet of the reaction chamber and are guided to be discharged into indoor air in the direction of a suction fan for collecting the oil fume, the peculiar smell gas and other harmful substances generated in cooking activities, so that part of the harmful substances which are not processed can be collected and processed again.
The oil smoke referred to in the invention refers to the smoke substance generated by edible vegetable or animal oil under the heating condition, wherein the smoke substance contains oil molecules, tiny oil drops or other chemical substances. Off-flavor gas refers to the unpleasant, irritating gaseous substances that are produced during cooking of food or cooking condiments. Other harmful substances are contaminants from the cooking heat source, such as carbon monoxide, carbon dust, dust or harmful gaseous organic substances.
Has the advantages that: the technology for treating cooking fumes, odorous gases and other harmful substances proposed by the present invention has the following advantages over the conventional fume extraction methods.
First, if a full indoor discharge method is used, the piping to the outside can be omitted. Thereby reducing the building cost and saving the cost of pipeline installation. Secondly, overcome the use restriction of traditional smoke ventilator. The indoor lampblack-free emission method is suitable for any house, including apartment houses. The relation between the position of the cooking bench and the position of the window and the relation between the upper floor and the lower floor are not needed to be considered, so that the house is designed more freely. And thirdly, oil smoke and peculiar smell which are discharged to the outside are avoided, the pollution to the atmosphere or a sewer is avoided, the smoke discharging direction is not limited, and the life of neighbors is not influenced. Fourthly, indoor pollution is reduced, oil smoke is eliminated, and oil mist is difficult to agglomerate on the inner surface and the outer surface of the exhaust fan and the processing device, so that the oil dripping problem of the traditional range hood is solved, and the cleaning work is greatly reduced. Fifth, because of the elimination of long exhaust ducts and dense filters, the required fan power is reduced, so that noise can be reduced to a minimum. Sixth, most of the off-flavors are eliminated. And seventh, potential safety problems (such as pipeline rupture in the wall, fire caused by oil collection in the pipeline, motor burnout caused by oil stain condensation of a fan shaft and the like) do not exist. Eighth, the installation and maintenance costs are low (no through-wall drilling, no installation by a dedicated person). The present invention also provides the aforementioned third, fourth, sixth and seventh advantages if a method of discharging the treated gaseous mixture to the outside is employed.
Drawings
Fig. 1 is a schematic view of a portable lampblack processing device according to an embodimentof the invention;
FIG. 2 is a schematic cross-sectional view of the reaction chamber of FIG. 1.
Fig. 3 is a schematic view of another portable lampblack treatment device in an embodiment of the invention;
FIG. 4 is a schematic view of a third stationary-type lampblack treatment device according to an embodiment of the invention;
fig. 5 is a schematic view of a four grill type lampblack treatment device according to an embodiment of the invention.
In the figure: 1-a cooking pot, 2-a cooking bench, 3-cooking oil, 4-a burner, 5-a pipeline, 6-a valve, 7-a smoke collecting hood, 8-a telescopic pipe, 9-an exhaust fan, 10-an exhaust fan, 12-a power line, 13-a ventilation pipe, 14-a reaction chamber, 15-a gap between the burner and the reaction chamber, 16-pot circle, 17-outlet of reaction chamber, 18-circulation guide plate, 19-catalyst net, 20-adsorbent net, 21-hole on pot circle, 22-another burner, 23-gas valve, 24-another reaction chamber, 25-metal barbecue plate, 26-fuel box, 27-dining table, 28-lighting lamp, 29-open valve, 30-solid fuel.
Detailed Description
The first embodiment is as follows: as shown in fig. 1, a cooking pot 1 is placed on a cooking range 2. The pot contains cooking oil 3. The gas enters the burner 4 through the pipeline 5 and the valve 6, and after the gas is burnt and heated, the cooking oil is heated to generate oil smoke. Most of the oil smoke will be collected by the smoke collecting cover 7 of the portable oil smoke processing device. Air, oil smoke, peculiar smell gas and some harmful gaseous substances from gas combustion enter the telescopic pipe 8 under the action of the exhaust fan 9 driven by the exhaust fan 10 to form a special gaseous mixture (the telescopic pipe is used for adjusting the distance between the smoke collecting hood and the cooking appliance). The mixture continues through the draught tube 13 into the reaction chamber 14 under the action of the suction fan. After treatment, the waste water is discharged from the outlet 17 of the reaction chamber and is directly discharged into the chamber through the guide of the circulating guide plate 18. The element 16 in the figure is a pot ring placed on the reaction chamber and used to support the cooking utensil. The component 11 is a power switch. The component 12 is a power cord. The portable oil fume treatment device basically meets the condition that the oil fume can be fully oxidized in the reaction chamber. First, the reaction chamber is made of metal or alloy (e.g., stainless steel) into a circular tubular shape (see fig. 2 for details) and is fitted around the periphery of the cooktop burner. The gap 15 between the burner and the inner side of the reaction chamber cannot be too small, otherwise the combustion of the gas is affected. However, the gap should not be too large, otherwise only a small part of the heat energy generated by the combustion of the gas is transferred to the reaction chamber, so that the temperature therein is not sufficient to promote complete oxidation of the soot. The vent 13 is also made of metal or alloy (e.g., stainless steel) and is directly connected to the inlet of the reaction chamber. The heat energy generated by gas combustion is transferred to the reaction chamber by conduction, convection and radiation, and then is partially transferred to the ventilation pipe by conduction, so that the temperature in the pipe is higher as the pipe is closer to the reaction chamber. This causes the gaseous mixture passing therethrough to be progressively heated with the aim of maintaining the aerosol particles sufficiently small for dispersion. In other words, the vent pipe also has a preheating function. In addition, it is also the support frame of collection petticoat pipe,air exhauster and flexible pipe.
Fig. 2 is a schematic cross-sectional structure diagram of the reaction chamber of the portable lampblack treatment device. According to experiments, the method for directly sucking the oil fume, the peculiar smell gas and other harmful substances by the exhaust fan can ensure that the formed gaseous mixture contains enough oxygen so that the oxidation reaction in the reaction chamber can be fully carried out. After this mixture has passed through the draught tube 13 into the reaction chamber 14, it will pass through at least one catalyst mesh 19. It is made up by spraying noble metal platinum or palladium on the surface of reticular nickel wire. The gas enters the burner 4 through the pipe 5, and the heat energy generated by the combustion is transferred to the reaction chamber, so that the temperature is raised to be high enough. Under the auxiliary action of the catalyst, the oil fume, the peculiar smell gas and other harmful substances start to be decomposed or oxidized. After passing through a sufficiently long reaction chamber channel (thereby ensuring a sufficiently long reaction time) will pass through the sorbent web 20. At this time, the soot and some of the offensive odor gas and other harmful substances are oxidized or decomposed. Part of the untreated odor gas and other harmful substances are adsorbed by the adsorbent and are left to be treated when the next cooking is carried out. All reaction products and gaseous substances which have not been treated and which have not participated in the reaction, except for those which have been adsorbed, are discharged from the outlet 17 of the reaction chamber and are then directed upwards through the circulation guide 18 to be discharged into the air. These rising gases may be sucked up again by the suction fan, so that part of the untreated pollutants in the gases is treated again by the reaction chamber. Thereby improving the processing efficiency. The part 16 in thisfigure is a pot ring for supporting the cooking utensil, carbon dioxide and water vapour produced by the combustion of the gas and a small amount of noxious substances can be discharged through the holes 21 in the pot ring, while part of the discharged noxious substances can be pumped into the reaction chamber for treatment. In addition, the reaction chamber can also be in a spiral surrounding shape, and the inner cavity can be provided with guide plates which are arranged in a staggered way. Experimental results show that the portable oil fume treatment device can well remove oil fume, has a certain effect on eliminating peculiar smell gas and can completely realize indoor emission. The processing device can be conveniently placed on different cooking ranges and different cooking holes for use.
Example two: another portable cooking fume treatment apparatus is shown in fig. 3, which is different from the former treatment apparatus only in that the ventilation pipe 13 is connected to two reaction chambers disposed on different cooktops. The purpose is to fully utilize the heat energy of different burner to separate part of the oil smoke and other harmful substances to the burner which is burning but does not produce oil smoke and harmful substances for treatment. Therefore, the power of the exhaust fan can be increased, the oil smoke and other harmful substances can be sucked to the maximum extent, and the treatment efficiency is improved.
Example three: the fixed type oil fume processing device is a fixed type oil fume processing device, as shown in figure 4, the fixed type means that a fume collecting hood 7, an exhaust fan 9, a ventilation pipe 13 and other parts are connected together and fixed on a wall like a traditional oil fume exhaust ventilator. The vent tube elbow and the vent tube straight tube form a long vent line and are connected to the reaction chamber 14. The reaction chamber is also placed on a burner of the cooking top 2, as in the first two embodiments, and the heat energy generated by the combustion of the gas in the burner of the burner provides the high temperature required in the reaction chamber and the energy required for preheating the mixture in the metal chimney. The oil smoke, the peculiar smell gas and other harmful substances collected by the smoke collecting hood 7 are oxidized or decomposed by the oxygen sucked together under the action of high temperature and catalyst after entering the reaction chamber through the ventilation pipeline. Part of the untreated odor gas and other harmful substances are adsorbed by the adsorbent in the reaction chamber and are left to be treated when the next cooking is carried out. All reaction products and gaseous substances which have not been treated and which have not reacted, except for those adsorbed, are discharged from the outlet 17 of the reaction chamber and then are directed upwards through the circulation guide 10 to be discharged into the air. It is possible that these rising gases are again sucked up by the suction fan 10, so that some of the untreated harmful substances are again treated by passing through the reaction chamber. As in the first two cases, the vent tube is also made of metal or alloy, and also has the function of preheating the reactants.
Example four: is a cooking fume treating apparatus which is different from the treating apparatus of the first three embodiments and is used for treating cooking fume, odor gas and other harmful substances generated when the food is cooked by using charcoal or the like solid fuel 30. As shown in fig. 5, the treating apparatus has two symmetrically disposed suction fans 1 and a hood 7. Charcoal or other solid fuels may produce noxious substances such as carbon dust, soot, and carbon monoxide when burned. Most of the heat generated by the combustion is used to heat the metal grill plate 25. The food on the barbecue plate, such as cooking oil, eggs, meat, vegetables and thelike, generates oil smoke and peculiar smell gas after being heated. Most of the oil smoke and peculiar smell gas and the harmful substances generated when the fuel is burnt are sucked by the two exhaust fans, and form a special gaseous or fog-state mixture with the simultaneously sucked air. The mixture is preheated by the action of an extraction fan through a metal vent pipe 13 and enters a reaction chamber 14. Inside the reaction chamber there is a catalyst net 19 and a number of sorbent nets 20. The harmful substances in the mixture are oxidized or decomposed under the action of high temperature and catalysis. Part of the odor and other harmful substances which are not treated are adsorbed by the adsorbent in the reaction chamber and are left to be treated when the next cooking is carried out. All reaction products and untreated and unreacted gaseous species, except those adsorbed, are discharged from the outlet 17 of the reaction chamber. The outlet is provided with a filter screen for filtering solid particles such as carbon powder and soot which can not be treated in the mixture. This solid waste can be periodically removed by opening valve 29. Like the three aforementioned treatment devices, the thermal energy required to maintain high temperatures within the reaction chamber comes from the combustion of solid fuels. The heat of combustion is transferred from the cartridge 26 to the surface of the reaction chamber made of metal or alloy by conduction, convection and radiation, and then to the reactants inside. Part of the heat energy is also transferred upwards through the surface of the vent tube made of metal or alloy, preheating the gaseous mixture passing therethrough. The draft tube design also supports the upper components of the draft fan and smoke collection hood, while the entire treatment unit is placed on the table 27. In the figure, 28 is an illumination lamp.
The embodiment of the method of the invention comprises the following steps: at least one exhaust fan is used for collecting oil fume, peculiar smell gas and other harmful substances generated in the cooking activity. Under the action of the suction fan, the air and the air involved therewith form a gaseous, fog or other mixture. The mixture enters at least one reaction chamber after passing through at least one vent pipe under the action of an exhaust fan. The mixture is preferably preheated before entering the reaction chamber. In the reaction chamber, the oil fume, the peculiar smell gas and other harmful substances in the mixture are directly oxidized into carbon dioxide and water by oxygen molecules contained in the mixture, or are firstly decomposed into intermediate products, and then the intermediate products are oxidized into the carbon dioxide and the water. The reaction product and the substances which do not participate in the reaction and do not participate in the reaction in the mixture can be discharged from the outlet of the reaction chamber and directly enter the air indoors or outdoors. To ensure the oxidation reaction proceeds smoothly, the temperature in the reaction chamber should be maintained at a high level. The heat energy required to maintain the high temperature in the reaction chamber and to preheat the mixture before it enters the reaction chamber comes from the heat source for cooking. One possible option is that the heat energy is taken from the heat source itself which is being used for cooking and which causes the production of fumes, off-flavors and other harmful substances. In order to enhance the treatment of soot, odorous gases and other harmful substances and to suitably reduce the high temperatures required to sustain the oxidation reaction, it is preferable to place a certain amount of catalyst and adsorbent in the reaction chamber. In order to reduce the possibility of solid substances contained in the above mixture, such as soot and carbon dust, escaping from the reaction chamber, it is preferable to add a filter screen near the outlet of the reaction chamber. In order to further improve the treatment efficiency, the gaseous mixture discharged from the reaction chamber may be collected again by the suction fan, so that a part of the harmful substances which have not been treated can be treated again by passing through the reaction chamber.
As is well known, fats and oils are a generic term for higher fatty acid glycerides. It is called oil which is liquid at room temperature and fat which is solid. The composition of these hydrocarbon groups in natural edible oils and fats is not the same, but is composed of three elements of carbon, hydrogen and oxygen in any case.
Under the condition of proper temperature and sufficient air supply, the oil fume formed by the edible oil can be fully oxidized. The general reaction formula can be written as:
wherein X, Y and Z represent the number of atoms of carbon, hydrogen and oxygen in the oil molecule, respectively, (O)2+3.76N2) Representing the composition of air.
If the supply of air is insufficient, carbon monoxide may be generated:
wherein W represents the number of moles of carbon monoxide.
In order to sufficiently remove oil fume and odor and ensure that secondary pollutants such as carbon monoxide are not generated during the treatment process, the following conditions are preferably satisfied in the reaction chamber in order to achieve complete indoor discharge.
1. Sufficiently high reaction initiation temperature
Both reactions are exothermic, but must first be provided with a sufficiently high reaction start temperature to proceed successfully. For typical hydrocarbons, the temperature should not be below 500 ℃. For the oxidation of edible vegetable oil fume, the temperature is preferably not lower than 550-600 ℃. This temperature can be suitably reduced using a specific catalyst, but it must not be lower than 150 ℃. Because the oil fume continuously enters the reaction chamber, the reaction chamber must be ensured to have continuous high temperature. The heat energy for maintaining the high temperature in the present invention is from the heat source of the cooking range. For example, it may come from a cook top that is being used for cooking and causes the production of fumes, off-flavor gases and other harmful substances. Or from other ports on the same cooktop. The cooking range may be a gas fuel range, such as a gas or natural gas range; can be a solid fuel range such as a coal range or a charcoal range; can be a liquid fuel range, such as a kerosene range; but also a range using electric or electromagnetic energy or other types of ranges. From the viewpoint of energy form, the thermal energy for maintaining the high temperature in the reaction chamber may be derived from chemical energy, electric energy or electromagnetic energy. There are numerous specific embodiments of how the heat energy generated by the above-described energy forms can be transferred into the reaction chamber.
For example, when the cooking hob is a gas or natural gas hob, a possible embodiment is to manufacture the reaction chamber from a metal or alloy, one open end of which is connected to a ventilation duct as an inlet for a mixture containing fumes, odorous gases and other harmful substances. The other open end serves as an outlet for the treated mixture. The reaction chamber is placed in the vicinity of the burner, preferably in direct contact with the gas flame, so that a portion of the heat energy generated by combustion can be transferred by conduction, convection and/or radiation to the metal or alloy sheath of the reaction chamber and then to the mixture in the chamber.
2. Sufficiently long reaction time
Heat burners are commonly used in industry to eliminate gaseous hydrocarbons from air. The residence time required for complete oxidative combustion of gaseous hydrocarbons in a thermal combustion furnace is typically in the range of 0.3 to 0.5 seconds. The residence time of cooking oil fume in the reaction chamber is preferably not less than 0.3 second. The retention time of the odorous gas is preferably not less than 0.5 seconds. Assuming that the flow velocity of the mixture in the reaction chamber is V (m/s) and the flow path is L (m), L is preferably not less than 0.3V (m) for the soot and not less than 0.5V (m) for the odorous gas. However, in practice L cannot be too long, and one possibility is to take L0.3V (meters) or less and to subject the gaseous mixture exiting the reaction chamber to a second treatment with the harmful substance which has not yet been treated, by collecting it again by means of an extraction fan.
3. Sufficient oxygen supply
As mentioned above, in order to sufficiently oxidize soot, odor and other harmful substances without generating secondary pollutants such as carbon monoxide, it is necessary to ensure that the mixture near the reaction chamber contains sufficient oxygen. It is known that the use of gas ranges or gas-type water heaters in a narrow and closed room is dangerous. Since the combustion of the gas will consume a limited amount of oxygen in the chamber. Over time, insufficient oxygen supply may result in incomplete combustion and the production of harmful carbon monoxide. But it is completely safe as long as the room door and window are opened to make the oxygen supply no longer limited. The amount of oxygen required for oxidation of soot, off-flavor gases and other harmfulsubstances is much smaller than for combustion of coal gas. Experiments show that in a non-closed room, no matter an axial flow fan or a centrifugal fan is used, a large amount of air can be sucked incidentally while oil smoke, odor gas and other harmful substances are sucked, and oxygen contained in the air is enough to completely oxidize the harmful substances without generating carbon monoxide. On the other hand, carbon dioxide generated by oxidation of soot, odor gas and other harmful substances is negligible compared to fuel combustion, and can be discharged indoors without affecting the composition of indoor air.
4. Sufficiently small and dispersed oil mist form
It has been observed that the so-called soot arising from the rising of hot edible fat is not a completely gaseous substance, but rather is present in the form of an aerosol, more precisely called oil smoke. Generally, once the oil molecules leave the hot cookware, the temperature will drop immediately and aerosol particles will form quickly. As the temperature further decreases, these particles can grow by engulfming each other. Upon encountering a cooler solid surface, such as the fan blades of a fan, it condenses into an oil and adheres thereto. However, if the oil fume is reheated, the grown aerosol particles can be reduced, and the oil cannot be adhered to the hotter solid surface.
If the aerosol particles in the oil fume entering the reaction chamber are too large, only the oil molecules on the surface of the particles will be oxidized and the rest of the molecules will not be processed within a limited reaction time. More seriously, if the ventilation duct connecting the suction fan and the reaction chamber is not properly designed and the temperature inside the ventilation duct is too low, most of the collected oil fume may be condensed on the inner wall of the duct and cannot enter the reaction chamber.
Therefore, for sufficient oxidation of the soot molecules, it is desirable that the soot entering the reaction chamber be in a dispersed mist state, wherein the aerosol particles should be as small as possible (and certainly better if they are in a completely gaseous state). This is achieved by a number of measures, one simple and practical method being to preheat the oil fume before it enters the reaction chamber. There are various preheating methods, one of which is to manufacture the ventilation duct with a material having good heat conductivity, such as metal, so that the heat energy of the reaction chamber can be transferred to the ventilation duct by conduction and radiation. The temperature of the part of the pipe which is closer to the reaction chamber is higher, the oil smoke passing through the pipe is gradually heated, and the aerosol particles are distributed in a small and dispersed way and can not be adhered to the inner wall of the pipe. The heat energy required by the preheating method is also provided by the heat source of the cooking stove.
Another possible preheating method is to provide an additional heat source, such as an electrical heating element, in the ventilation duct. The electrical energy required for the heating of the element is provided by a further power supply. If the power is high enough, the temperature in the ventilation duct will be high enough, and part of the soot may be oxidized before entering the reaction chamber. However, the excessive electric heating power consumes too much electric energy, and is not necessarily suitable from the energy-saving viewpoint.
5. Suitable auxiliary means
Compared with oil smoke, the odor gas is more difficult to eliminate. It requires higher temperatures and longer reaction times. Cooking stoves in general, and electric stoves in particular, do not necessarily allow the reaction chamber to reach the desiredtemperature. The compensation is preferably made by appropriate auxiliary means.
(1) By means of adsorbents
The adsorption amount of the adsorbent generally decreases with increasing temperature and increases with decreasing temperature. When the temperature in the reaction chamber is lower, the adsorbent can adsorb more odor gas which is not oxidized or decomposed. When the temperature in the reaction chamber is higher, the adsorbed odor gas is less, but the proportion of the odor gas which can be oxidized or decomposed is also increased. Another role of the adsorbent is more important. When the cooking operation is finished, people usually cut off the energy supply of the cooking range, such as turning off the gas. The temperature in the reaction chamber, which is supplied with thermal energy by means of the cooking range, rapidly drops. If the peculiar smell gas or the oil fume still escapes from the cooking utensil, the peculiar smell gas or the oil fume cannot be fully oxidized or decomposed after entering the reaction chamber, and the cooking utensil is polluted once being discharged from the reaction chamber. However, if an adsorbent is placed in the reaction chamber, the residual harmful substances can be adsorbed at this time. The adsorption is strong because the temperature is greatly reduced. By the next cooking, the temperature in the reaction chamber rises again and the adsorbed harmful substances may escape again from the adsorbent, either immediately be treated in the oxidation chamber or be pumped again for a second treatment after being discharged from the oxidation chamber. The adsorbent is regenerated and has the ability to adsorb the residual peculiar smell gas or oil smoke after the next cooking stop. In this process, the adsorbent actually serves to extend the reaction time. Taking into account the high temperature and the strongly oxidizing atmosphere inside the reaction chamber. Adsorbents such as ion exchange resins and activated carbons are not preferred. Natural or synthetic zeolites have good high temperature strength and excellent adsorption capacity, but are relatively expensive. The activated alumina has high temperature resistance, is not easy to oxidize, has better adsorption capacity to vapor and peculiar smell gas, and has not very high price. Silica gel has a strong adsorption capacity for water vapor, but the high-temperature strength is not very good. The greatest advantage of using mineral wool or glass fibre is that it is very inexpensive. Although the adsorption capacity is poor, the self-activation capacity is strong, and the self-activation capacity does not need to be replaced once the reaction chamber is placed.
The adsorbent may be placed in the reaction chamber in a variety of ways. For example, when silica gel or activated alumina powder is used, the adsorbent powder may be supported by a gas flow containing the harmful substance from bottom to top in a fluidized bed form, and adsorbed in a fluidized state. If mineral wool or glass fiber is used as the adsorbent, it can be made into a net shape to allow the gas flow to pass through it for adsorption.
The adsorbent is preferably not placed in the ventilation duct or in front of or behind the exhaust fan, otherwise the oil smoke would quickly saturate the adsorbent and no longer adsorb the odorous gases. The soot rich adsorbent is also difficult to regenerate. The adsorbent is adapted to be placed in the reaction chamber adjacent the outlet. Because most of the oil smoke is oxidized into carbon dioxide and water at the position, the adsorption of the adsorbent to the odor gas is not influenced.
(2) Using catalysts
The temperature required for the oxidation or decomposition of the odorous gas molecules can be suitably reduced by using the catalyst. Most catalysts are not high temperature resistant and are easy to poison and lose efficacy under an oxidizing atmosphere. The number of catalysts available for selection is not too great. Platinum with nickel or its alloy as carrier, and catalyst is one of the choices. One possible method is to form the catalyst in the form of a screen and to pass the stream of noxious substances through one or more catalyst screens placed in the reaction chamber. Due to the high temperature in the reaction chamber, the oil smoke can not be adhered to the filter screen, so that the peculiar smell gas can directly contact with the catalyst and be decomposed or oxidized at a lower temperature. Unlike the adsorbent, the catalyst is not strictly placed in the reaction chamber, and is generally placed near the middle section of the reaction chamber. After the catalyst filter screen is used for a period of time, carbon deposit or other dirt can appear on the surface. The cleaning method is various, and the simpler method is to soak the filter screen with alcohol and then lightly scrub the filter screen, so that the platinum and the plating layer are not damaged. After carbon deposit or dirt is removed, the mixture is dried and placed into a reaction chamber for continuous use.
In general, the service life of a catalyst depends on various factors such as the type, quality, service temperature, gas flow composition, concentration and flow rate of the catalyst. In order to prolong the service life of the catalyst, the temperature in the reaction chamber should be reduced as much as possible under the premise of ensuring the sufficient oxidation of the oil smoke.
(3) By cyclic treatment
There are two methods for discharging the mixed gas from the reaction chamber into the air. One is to discharge to the outdoor atmosphere through a pipe connecting the outlets of the reaction chambers. One is to discharge directly from the outlet of the reaction chamber into theroom. In the latter method, the mixed gas discharged from the reaction chamber is guided to be discharged toward the exhaust fan. So that part of the mixed gas discharged from the reaction chamber is not directly discharged into the air in the room, but is sucked again by the suction fan and enters the reaction chamber through the ventilation pipe for secondary treatment. Under the conditions of meeting the requirements of the above-mentioned sufficiently high reaction temperature, sufficiently long reaction time, sufficient oxygen supply, small and dispersed oil mist form and proper auxiliary means, the mixed gas discharged from the reaction chamber is formed from unreacted nitrogen gas, unreacted oxygen gas, carbon dioxide and water vapour produced by reaction, small quantity of abnormal-smell gas which can not be decomposed, oxidized or adsorbed and very small quantity of oil smoke. The cyclic treatment process may allow part of the off-flavor gases to be treated for a second time. The method has another function of recycling the heat energy. The conventional range hood not only pumps out part of the oil smoke and the peculiar smell gas, but also brings out part of the heat energy generated by the cooking stove to the outside. In the present invention, if the circulation treatment process is adopted and the indoor discharge is completed, most of the heat energy generated from the cooking range is concentrated around the range, so that the cooking area is maintained at a higher temperature for a longer time, thereby causing the positive and negative effects. On one hand, the cooking area, especially the part close to the exhaust fan, has higher temperature, so that the oil smoke is not easy to condense on the surfaces of the fan cover, the fan blades and the ventilation pipeline, and the difficulties of oil dripping, oil leakage and difficult cleaning caused by the traditional range hood are avoided. On the other hand, however, the higher temperatures in the cooking zone also make the operator uncomfortable, especially if the cooking time is longer in summer. However, according to experiment and field operation, the temperature change is difficult to be perceived when cooking in a common home, and the temperature change is almost not different from that of the conventional range hood. When this method is used in a restaurant or other location where cooking is specifically performed, the temperature of the cooking area changes significantly. It is preferable to use outdoor discharge. The treated mixed gas exhausted from the reaction chamber is exhausted to the outdoor atmosphere via pipeline, and partial heat energy produced by the cooking stove is taken out of the room, so that the temperature in the cooking area is not too high.
Claims (10)
1. A device for treating cooking oil fume, peculiar smell gas and other harmful substances, one end of a ventilating duct is communicated with a suction fan near a cooking stove, and the device is characterized in that: the other end of the ventilation pipeline is connected with at least one annular reaction chamber with a cavity, the reaction chamber is sleeved on the periphery of the burner of the cooking stove and is provided with at least one outlet.
2. An apparatus for treating cooking fumes, odorous gases and other harmful substances according to claim 1, characterized in that: and an adsorbent capable of adsorbing partial reaction products and partial oil smoke, peculiar smell gas and other harmful substances which are not oxidized or decomposed is placed in the reaction chamber.
3. Apparatus for treating cooking fumes, odorous gases and other harmful substances according to claim 1 or 2, characterized in that: the reaction chamber is internally provided with a catalyst which can reduce the temperature required by the oxidation or decomposition of oil smoke, odor gas and other harmful substances.
4. Apparatus for treating cooking fumes, odorous gases and other harmful substances according to claim 1 or 2, characterized in that: and a filter screen capable of preventing solid particles from escaping from the reaction chamber is arranged in the reaction chamber.
5. An apparatus for treating cooking fumes, odorous gases and other harmful substances according to claim 1, characterized in that: a preheating device for heating and cooking oil fume, peculiar smell gas and other harmful substances is arranged between the ventilating pipe and the reaction chamber or in the ventilating pipe.
6. An apparatus for treating cooking fumes, odorous gases and other harmful substances according to claim 1, characterized in that: the outlet of the reaction chamber is connected with a circulating guide plate or an additional pipeline communicated with the outdoor atmosphere.
7. A method for treating cooking fumes, odorous gases and other harmful substances, characterized in that: the exhaust fan is communicated with at least one ventilation pipeline and then enters at least one reaction chamber, in the reaction chamber, oil smoke, peculiar smell gas and other harmful substances in the mixture are directly oxidized into carbon dioxide and water by oxygen contained in the mixture, or are firstly decomposed into intermediate products, the intermediate products are oxidized into the carbon dioxide and the water, all the reaction products and the substances which do not participate in the reaction and do not participate in the reaction in the mixture are discharged from an outlet of the reaction chamber and enter the air, a high temperature level is maintained in the reaction chamber, and the heat energy required for maintaining the temperature in the reaction chamber comes from a heat source of a cooking stove.
8. A method of treating cooking fumes, off-flavor gases and other harmful substances according to claim 7, characterized in that: the temperature in the reaction chamber is not lower than 100-200 ℃.
9. A method of treating cooking fumes, off-flavor gases and other harmful substances according to claim 7, characterized in that: a preheating device for heating and cooking oil fume, peculiar smell gas and other harmful substances is arranged between the ventilating pipe and the reaction chamber or in the ventilating pipe, and the heat energy required by the device is from an additional heat source of the non-cooking stove.
10. A method of treating cooking fumes, odorous gases and other harmful substances according to claim 7 or 9, characterized in that: after the mixture containing the oil fume, the peculiar smell gas and other harmful substances is treated in the reaction chamber, reaction products and substances which do not participate in reaction and do not participate in reaction in the mixture are discharged from an outlet of the reaction chamber and are guided to be discharged into indoor air in the direction of a suction fan for collecting the oil fume, the peculiar smell gas and other harmful substances generated in cooking activities, so that part of the harmful substances which are not treated can be collected and treated again.
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| CNB021595410A CN1166895C (en) | 2002-12-30 | 2002-12-30 | Apparatus and method for treating cooking fume, peculiar small gas and other harmful substance |
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| CNB021595410A CN1166895C (en) | 2002-12-30 | 2002-12-30 | Apparatus and method for treating cooking fume, peculiar small gas and other harmful substance |
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| CN1166895C CN1166895C (en) | 2004-09-15 |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005106456A1 (en) * | 2004-04-30 | 2005-11-10 | Zongyan He | A method for in situ detecting the oil smoke concentration and a device thereof |
| CN101785615A (en) * | 2009-01-23 | 2010-07-28 | 南方汇通股份有限公司 | Rapid cooling and deodorizing method for plant-fiber mattress and device thereof |
| CN102183053A (en) * | 2011-04-22 | 2011-09-14 | 绍兴文理学院 | Environment-friendly integrated kitchen ware |
| CN103962002A (en) * | 2014-05-22 | 2014-08-06 | 苏州意玛斯砂光设备有限公司 | High-temperature waste gas treatment device |
| CN106164588A (en) * | 2014-04-28 | 2016-11-23 | 曺永子 | Smoke treating device |
| CN106175479A (en) * | 2016-08-30 | 2016-12-07 | 宁波方太厨具有限公司 | A kind of electric baker and control method thereof |
| CN111006259A (en) * | 2019-12-11 | 2020-04-14 | 张跃虎 | Air supply control system of oil smoke self-purification stove |
| CN113522019A (en) * | 2021-08-16 | 2021-10-22 | 安徽坤健生物科技有限公司 | Air purification equipment for biological treatment of kitchen waste |
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2002
- 2002-12-30 CN CNB021595410A patent/CN1166895C/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005106456A1 (en) * | 2004-04-30 | 2005-11-10 | Zongyan He | A method for in situ detecting the oil smoke concentration and a device thereof |
| CN101785615A (en) * | 2009-01-23 | 2010-07-28 | 南方汇通股份有限公司 | Rapid cooling and deodorizing method for plant-fiber mattress and device thereof |
| CN102183053A (en) * | 2011-04-22 | 2011-09-14 | 绍兴文理学院 | Environment-friendly integrated kitchen ware |
| CN106164588A (en) * | 2014-04-28 | 2016-11-23 | 曺永子 | Smoke treating device |
| CN103962002A (en) * | 2014-05-22 | 2014-08-06 | 苏州意玛斯砂光设备有限公司 | High-temperature waste gas treatment device |
| CN106175479A (en) * | 2016-08-30 | 2016-12-07 | 宁波方太厨具有限公司 | A kind of electric baker and control method thereof |
| CN111006259A (en) * | 2019-12-11 | 2020-04-14 | 张跃虎 | Air supply control system of oil smoke self-purification stove |
| CN113522019A (en) * | 2021-08-16 | 2021-10-22 | 安徽坤健生物科技有限公司 | Air purification equipment for biological treatment of kitchen waste |
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| Publication number | Publication date |
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