RU2171033C1 - Infrared radiation method and apparatus for producing smoke - Google Patents

Abstract

FIELD: food-processing industry. SUBSTANCE: method involves generating smoke from wood sawdust with specific surface of 9-12 sq.m/kg and moisture content of 50-70%; using infrared radiation generators as heat sources; adding water to sawdust in an amount of 50-100 wt% and switching on smoke generators. Mentioned conditions allow decomposition temperature to be maintained at the level below 320 C. Such temperatures do not provoke formation of significant amounts of cancerogenic and procancerogenic substances. Apparatus has housing with smoke generating chamber incorporating pyrolysis bath with two side pockets. Auxiliary reflecting surface and baffle are arranged above pyrolysis bath. Water is supplied into side pockets and space between pockets is filled with sawdust having moisture content of 45-70%. Distance from bath to infrared radiation generators is selected experimentally depending on type of radiation generators. It is advisable that apparatus with increased smoke generation capacity be equipped with conveyor. Method allows smoke free from cancerogenic and procancerogenic substances to be produced in apparatus which does not require continuous maintenance and operation. Method and apparatus are generally used for production of cold and hot smoke meat and fish products. EFFECT: simplified method and construction, improved quality of smoke and wider range of smoke products. 3 cl, 2 dwg, 7 ex

Description

 The invention relates to the food industry and can be used in the production of meat and fish products of hot and cold smoked.

 A known method of producing smoke by thermal decomposition of wood sawdust using dry superheated steam (Ershov A.M., Zotov V.V., Nozdrin S.I. Smoked food products: study guide part 2 Improving energy efficiency - Murmansk: MSTU, 1996, p. 86-89). In this method, saturated water vapor is heated to high temperatures and passed through a layer of sawdust. The smoking environment resulting from the decomposition of sawdust is cleaned of solid particles, cooled and used in the process of smoking the product.

This method is carried out in a device known from the same literature (Ershov A. M., Zotov V.V., Nozdrin S.I. Smoking of food products: a manual, part 2 Improving energy efficiency. - Murmansk, MSTU, 1996, - p . 86-89), consisting of a housing, inside of which there is a screw, which serves for feeding and pyrolysis of sawdust. In the middle part of the screw there is a sawdust pyrolysis zone. At the inlet and outlet of the pyrolysis zone, there are openings for supplying and discharging steam. At the exit from the pyrolysis zone, a baking powder is installed in the screw. In the upper part of the housing are heat exchangers, a heater and a jet pump, which serve to superheat steam and supply superheated steam into the auger with moving sawdust. At the exit from the pyrolysis zone, a cyclone was installed to clean the smoking environment from sawdust. In the lower part of the body is a collection of ash. Since the pyrolysis of sawdust occurs at temperatures no higher than 380 ^o C, in the smoking environment contains a small amount of carcinogenic and carcinogenic substances. When using superheated steam, the properties of the resulting smoke medium differ from the properties of smoke obtained by traditional methods, therefore, the taste properties of smoked products prepared using this medium also differ. The devices are complex and metal-intensive, so this method has not found wide application in industry.

 Closest to the proposed invention relating to a method for producing smoke, is the method according to RF patent N 2115322, IPC A 23 B 4/052 (published in BI N 20, 1998).

This method consists in producing smoke from smoke by friction of wood with a moisture content of 50-70% about a rotating metal drum. Pyrolysis in the friction zone is low temperature, as it occurs at a temperature not exceeding 350 ^o C, which contributes to a sharp decrease in the content of carcinogenic and carcinogenic substances. Taste properties of products prepared using smoke obtained by this method do not differ from the taste properties of traditional smoked products. However, in the process of pyrolysis, the surface layers of wood dry out, and at the end of the process they may ignite, which contributes to the formation of harmful substances. As a result, smoke condensates and smoked products contain some benz-a-pyrenes and nitroso compounds.

 Closest to the proposed invention is a device according to A.S. USSR N 1755767, class A 23 B 4/044, (published in BI N 31, 08/23/1992).

 The device for smoking food products contains a housing, in the lower part of which there is a bath for sawdust, and below it a grill for food products. A cap is installed above the bath, while the bath and cap have at least two internal partitions located parallel to their walls. The walls and partitions of the cap are placed between the partitions of the bath so that they form channels open from the ends between the end walls and the bottom of the bath and the cap, in the lower part of which filter material is placed. The central partition of the bath is in contact with the bottom of the cap, it is made in height more than the other partitions and is equipped with holes in the upper part. The grill for placing the product is mounted on the hood. The presence in the device of the cap of the partitions located between the partitions of the bath, and the filter material filling the space between the partitions, ensures the cleaning of smoke from soot and other products of sawdust pyrolysis.

 In this device, the pyrolysis of wood is carried out by burning part of the fuel, that is, in unregulated temperature conditions, which leads to an uncontrolled increase in the temperature of wood fuel with the formation of a large number of carcinogenic and carcinogenic substances. The filters used can trap large particles of soot, partly tar, but are not able to reduce the content of substances harmful and dangerous to human health in smoke. In addition, the combination of the smoke chamber with the product smoking chamber itself also negatively affects the quality of the products.

The proposed inventions solve the problem of obtaining high-quality smoke with a minimum content of benz-a-pyrenes and nitroso compounds in simple in design, reliable and not requiring constant maintenance devices. To achieve such a technical result, in the proposed method for producing smoke, pyrolysis of wood fuel with a moisture content of 50-70% is carried out at a temperature not exceeding 320 ^o C, while water is added to wood sawdust with a specific surface area of 9-12 m ² / kg in an amount of 50- 100% of their mass, and pyrolysis is carried out by the energy of infrared radiation.

Distinctive features of the proposed method are heating wood fuel with infrared energy and adding water to the fuel at the beginning of the pyrolysis process in an amount of from 50 to 70% of its mass. These conditions allow you to maintain the decomposition temperature of sawdust at a level not exceeding 320 ^o C.

 To achieve the above technical result, a device is proposed which is a smoke generation housing with a pyrolysis bath, which is divided by partitions parallel to the walls of the bath, into separate zones for wood fuel (sawdust) and water, and the water zones form two side pockets. Above the bathtub are infrared radiation generators equipped with reflectors. An additional radiating surface is located between the infrared radiation generators and the reflectors. Water is poured into the side pockets of the pyrolysis bath, and wet fuel is placed between them. The distance from the infrared radiation generators to the fuel surface is selected experimentally depending on their type. For installations with high smoke output, continuously operating devices are recommended.

The described device design is more reliable and easier to maintain than the known smoke generators and allows you to produce high-quality smoke, free of carcinogens and carcinogens. The invention is illustrated by drawings, which depict:
in FIG. 1 is a diagram of a batch device for implementing the proposed method, a cross section;
in FIG. 2 is a diagram of a continuous device for implementing the proposed method, a longitudinal section.

 The proposed method is carried out in the following sequence: the fuel 9 is moistened to 45-70% moisture, then loaded into the bath 7 for pyrolysis, add 50-100% water from the mass of fuel 9 to the side pockets 8, after which the infrared radiation generators 2 are turned on and the process is carried out until complete thermal decomposition of the fuel 9, then the residue from thermal decomposition is removed and the cycle is repeated. It should be noted that a certain specific surface of the fuel, its moisture content and the amount of added water corresponds to a certain duration of the pyrolysis process, which can be set by a timer. Actually pyrolysis occurs without the participation of the operator.

 Example 1

Sawdust weighing 0.7 kg with a specific surface area of 9.0 m ² / kg and a moisture content of 44% was placed in a bath 7 for pyrolysis (Fig. 1), 0.35 kg of water was added to the side pockets 8 of the bath 7 for pyrolysis. The duration of heating before the start of smoke formation was 7 minutes, and the duration of smoke formation itself was 112 minutes. In the process of smoke formation, ignition of the fuel was observed.

 The mode is not recommended.

 Example 2

Sawdust weighing 0.7 kg with a specific surface area of 9.0 m ² / kg and a humidity of 45% was placed in the pyrolysis bath 7 (Fig. 1), 0.35 kg of water was added to the side pockets 8 of the pyrolysis bath 7. The duration of heating before the start of smoke formation was 7.3 minutes, and the duration of smoke formation itself was 115.7 minutes. Ignition of the fuel was not observed.

 Recommended mode.

 Example 3

Sawdust weighing 0.7 kg with a specific surface area of 11.0 m ² / kg and a humidity of 45% was placed in the pyrolysis bath 7 (Fig. 1), 0.45 kg of water was added to the side pockets of the 8 bath 7 for pyrolysis. The duration of heating before the start of smoke formation was 16.6 minutes, and the duration of smoke formation itself was 119.5 minutes. Ignition of the fuel was not observed.

 Recommended mode.

 Example 4

Sawdust weighing 0.7 kg with a specific surface area of 11.0 m ² / kg and humidity of 70% was placed in the bath 7 for pyrolysis (Fig. 1), 0.70 kg of water was added to the side pockets 8 of the bath 7 for pyrolysis. The duration of heating before smoke formation was 11.9 minutes, and the duration of smoke formation itself was 142.6 minutes. Ignition of the fuel was not observed.

 Recommended mode.

 Example 5

Sawdust weighing 0.7 kg with a specific surface area of 11.0 m ² / kg and humidity of 70% was placed in the bath 7 for pyrolysis (Fig. 1), 0.80 kg of water was added to the side pockets 8 of the bath 7 for pyrolysis. The duration of heating before the start of smoke formation was 13 minutes, after 10 minutes the process of smoke formation stopped.

 The mode is not recommended.

 Example 6

Sawdust weighing 0.7 kg with a specific surface area of 11.8 m ² / kg and humidity of 47% was placed in the pyrolysis bath 7 (Fig. 1), 0.35 kg of water was added to the side pockets of the 8 bath 7 for pyrolysis. The duration of heating before the start of smoke generation was 2.7 minutes, and the duration of smoke formation itself was 112.7 minutes. Ignition of the fuel was not observed.

 Recommended mode.

 Example 7

Smoke was generated for 72 hours according to the regime of Example 2. Smoke was passed through an absorber in which water was circulated at a temperature of 20 ^o C. 300 kg of smoking product was obtained, which corresponded to TU 2455-001-11796723-94 "Smoking product" SKVAMA ". Technical conditions". In the smoking product, there were completely no substances such as benz-a-pyrene and nitroso compounds, which can contribute to the oncological diseases.

 The proposed device for generating periodic smoke contains (Fig. 1) a housing 1 in which a number of infrared radiation generators 2 are placed, interconnected in parallel with live insulated wires. A block of reflectors 3 is located above the generators 2, which serve to reflect the radiation flux upward from the generators 2. An additional radiating surface 4 is used to generate a long-wave infrared radiation spectrum and to protect the reflectors 3 from pollution. Window 5 of the housing 1 serves to remove the generated smoke, and the damper 6 is designed to supply fresh air to the pyrolysis zone. A bath 7 for pyrolysis is placed under the infrared radiation generators 2. The bath 7 for pyrolysis is divided by partitions placed parallel to the walls of the bath, into separate zones for fuel and water, moreover, the water zones form two side pockets 8 into which a certain amount of water is poured. Fuel 9 is located in the middle zone of the pyrolysis bath 7. The guides 10 are designed to move the pyrolysis bath 7 to the zone of action of the infrared radiation generators 2.

 The proposed device for the generation of continuous smoke contains (Fig. 2) nodes of positions 1-9 for the same purpose as in FIG. 1, however, it is additionally equipped with the following parts and assemblies.

 In the middle zone of the pyrolysis bath 7, there is a scraper conveyor 11 having guides 10 for moving fuel 9 in the pyrolysis bath 7. The hopper 12, located on the housing 1, serves to dispense the supply of prepared fuel 9 to the pyrolysis zone. The hopper 12 is equipped with a agitator 13 and a control flap 14. On the opposite side of the fuel loading zone in the housing 1 is equipped with an ash collector 15 with a flap for unloading 16. The device for generating smoke is equipped with a pipe 17 for supplying water to the side pockets, which is regulated by a control valve 18 .

The periodic device operates as follows. From the housing 1 along the guides 10 extend the bath 7 for pyrolysis. A dose of fuel 9 with a certain humidity is placed in the middle zone of the pyrolysis bath 7, then a certain portion of water is poured into the side pockets 8 of the pyrolysis bath 7. After that, the pyrolysis bath 7 along the guides 10 is moved to the housing 1. The pyrolysis bath 7 on the loading side has an end wall of a larger area than the cross-sectional area of the hole through which the bath is extended from the housing, thereby touching this end wall at the moment of closure with the outer wall of the housing 1, uncontrolled access of air through the loading opening is closed. Then the infrared radiation generators are turned on. A part of the heat flux from the infrared radiation generators 2 is directed downward to the fuel 9, and a part enters the additional radiating surface 4, which partially reflects the heat flux, but partially absorbs and heats accordingly, but to a lower temperature than the radiating coil of the infrared generators 2. The heated radiating surface 4 begins to generate infrared radiation energy with a longer wavelength than the generators 2. The heat flux from the additional radiating surface 4, directed upward, is reflected by a reflector 3, the surface of which is protected from contamination by smoke from the additional radiating surface 4. Thus, the fuel 9, the energy flux of infrared radiation with a different wavelength operates, which ensures uniform absorption of heat fluxes by the fuel surface and reduces the possibility of ignition changes in its individual parts. Moreover, the energy loss of infrared radiation into the environment is small. Initially, the fuel is heated, and due to the combination of the infrared radiation flux with a certain moisture content of the fuel, the phenomenon of thermal moisture conduction takes place, as a result, the heating of the inner layers of wood sawdust is intensified. After a certain period of time, the pyrolysis of the upper layers of the fuel begins to occur. The supply of fresh air is regulated by a shutter 6. As the pyrolysis takes place, the thickness of the fuel layer decreases and at the end of the process, an ash residue of 10-12% by weight of the fuel remains. The use of fuel with a certain moisture content and the additional supply of moisture from the side pockets contribute to the fact that during the entire pyrolysis process, wood particles are surrounded by water vapor, which does not interfere with pyrolysis, but prevents their ignition, therefore, the pyrolysis process proceeds evenly at temperatures below 320 ^o C. After When the pyrolysis is complete, the generators 2 are turned off, the bath 7 is pulled out of the pyrolysis zone, the ash residue is removed, and the cycle is repeated.

A device for generating continuous smoke (Fig. 2) works as follows: the hopper 12 is loaded with prepared sawdust, the conveyor 11 and the agitator 13 are turned on, the sawdust is regulated by the shutter 14, then the infrared radiation generators 2 are turned on and the water supply to the side pockets 8 is opened via the pipeline 17, while the dose of water is regulated by the valve 18. The scrapers of the conveyor 11 move the fuel gradually through the bath 7 for pyrolysis, at the beginning of the bath 7 for pyrolysis the fuel is heated, and at the end of the bath 7 for pyrolysis of complete decomposition. Water is constantly supplied from the side pockets 8 of the bath 7 for pyrolysis. The water supply from the side pockets 8 to the pyrolysis zone in combination with a certain moisture content of the fuel promotes pyrolysis at temperatures less than 320 ^o C. The ash residue by conveyor scrapers 11 is removed into the hopper 15, from which it is periodically discharged using the shutter 16. The generated smoke is continuously discharged through the window 5.

Claims (3)

1. The method of producing smoke from the pyrolysis of wood fuel with a moisture content of 50-70%, characterized in that the pyrolysis temperature does not exceed 320 ° C, while to the wood chips with a specific surface area of 9-12 m ² / kg add water in an amount of 50-100% from their mass, and pyrolysis is carried out by the energy of infrared radiation.  2. A device for producing smoke, containing a body, a pyrolysis bath with partitions parallel to its walls, characterized in that it is equipped with infrared radiation generators, reflectors and an additional radiating surface, and the pyrolysis bath is divided by partitions into separate zones for wood fuel and water, while the water zones form two side pockets.  3. The device according to claim 2, characterized in that for the continuous process of smoke generation, a conveyor is placed in the fuel zone of the pyrolysis bath.

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