RU2135035C1 - Method and line for reprocessing of crab wastes to produce crab grits and crab flour - Google Patents

Abstract

FIELD: food-processing industry. SUBSTANCE: method involves freezing out armor-containing crab wastes including head and chest portions, abdomen, substandard limbs and crab canned product wastes; washing them with sea water and drying in two stages: first stage of preliminary drying until residual moisture content in raw material reaches 50-55% at raw material feeding rate of 0.45-0.55 t/hour and temperature of raw material at output end of preliminary drying apparatus of 35-40 C, second drying stage until residual moisture content in product is below 12%, temperature of raw material at output end of drying apparatus is equal to 60-90 C and flow rate of countercurrent air having temperature of 100-130 C is 2,250-2,750 cu.m/h; grinding dried raw material to obtain grits:flour ratio of (80-85):(15-20) and separating in vibrating sieve into crab grits and crab flour. Line has accumulating hopper 1, belt conveyor 2, gooseneck type conveyor 3, hopper with auger doser 4, preliminary drying apparatus 5 connected via pipeline to exhaust fan 6, drying apparatus 7, milling unit 10, pneumatic conveyor 11, cyclone 12 with unloader and auger feeder, vibratory sieve 13, bag holder 14 and check weigher 15. Method allows dry yield (flour and grits) to reach 22% at residual moisture content of 12%. EFFECT: wider operational capabilities, simplified method and construction and increased yield of dry product. 3 cl, 1 dwg, 4 ex

Description

 The proposed method and line for its implementation relate to the food industry and can be used to obtain crab grains, such as, for example, raw materials for the production of chitin and chitosan, protein-mineral components of feed for livestock, and feed flour used as a basic component of feed, including in fish farming.

 The closest technical solution is a method of manufacturing dried crab grains for industrial processing (TI N 419-91, approved by the Deputy General Director of the GPO "Dalryba" Antonyuk N. C 11.03.91), according to which raw materials for the production of dried crab grits are raw and boiled waste - the shell of the cephalothorax, walking and clawed limbs, obtained by cutting raw crab in the manufacture of canned and boiled - frozen crab meat. The technological process includes the reception of raw materials, its grinding, cooking, pressing, drying, separation of metal impurities, sorting grains by size, packaging.

Raw materials purified from crab meat residues are stored in storage bins. Grinding, cooking, pressing, drying, separation of metal impurities is carried out in accordance with the instructions for the manufacture of feed flour (instruction N 99 "Collection of technological instructions for processing fish", t. 2, M .. "Kolos", 1994, S. 512-526 ) The raw materials are crushed and loaded into a drying apparatus. Cooking - drying under vacuum is as follows: water is supplied to the dryer under a pressure of 0.2-0.3 MPa; raw materials are heated to a temperature of 75 - 80 ^o C, cook at this temperature for 20 to 25 minutes. Then, a vacuum of 0.04 to 0.05 MPa (300 - 400 mm Hg) is created in the dryer and drying begins. Drying of shrimp and crab raw materials is carried out in two stages: the first stage for 1.5 - 2.5 hours (crab raw materials - 1.5 - 2 hours), under heating steam pressure from 0.098 - 0.147 MPa, in a vacuum of 0.05 MPa (350 mm, Hg) at the beginning of the process, with a gradual decrease in pressure to 0.027 MPa (200 mm, Hg) at a temperature of 75 - 80 ^o C. The second stage of drying is carried out at a heating steam pressure of from 0.29 to 0.39 MPa and in a vacuum of 0.027 MPa at a temperature of 80-95 ^o C.

 The total drying time to a residual moisture content of dry product equal to 12% is 3-5 hours.

The one-stage process without the use of vacuum is carried out as follows: the raw materials are boiled for 2.5 - 3 hours by feeding heating steam into the drying chamber of the dryer and into the hollow shaft of the mixer. The temperature of the water leaving the condenser during cooking should be 60-70 ^o C, and by the end of cooking - 40 ^o C.

At the end of cooking, the steam supply is increased to the maximum possible limit so that the temperature of the steam formed inside the dryer is 80 - 90 ^o C, and dried for 2-2.5 hours. Dried crab raw material is served for grinding and then sorted by size. The particles of dried grits should have a size across not more than 10 mm. Next, dried grits are packed in bags with a capacity of up to 30 kg.

 The main disadvantages of the known method of producing grains include the periodicity of the process of obtaining products, low, due to the prolonged high-temperature processing of raw materials, the quality of the grains and its technical and chemical characteristics in terms of further industrial processing.

 The closest line for the production of crab groats is a block-type line for the production of fishmeal RMU I7-IVB, produced by the Nezhinsky Mechanical Plant, with a capacity of up to 8.5 tons per day for raw fish (control measurements of productivity: 4.5 tons per cod / day, for herring - 6.2 t / day, for halibut 6.6 t / day; the yield of flour at the same time is on average 16% with a 10% residual moisture content of the product). The overall dimensions and power consumption of the line units, an average of 16 kWh, make it possible to establish production directly in the marine industry (Romanov-A.A. Handbook of fish-processing plants and equipment, M., "Food Industry", 1975, p. 8 - 12).

The technological line includes the following complex of technological equipment:
(1) coarse material chopper
(2) hopper with screw feeder
(3) I7-IVB unit (varnik 3.1, press 3.2, dryer 3.3)
(4) tray with magnetic metal trap
(5) cyclone dryer with fan
(6) screw conveyor
(7) mill installation with fan
(8) pneumatic transport
(9) cyclone
(10) bag holders
(11) weighing - signaling device.

 The yield of flour obtained according to the direct drying scheme at RMU I7-IVB is on average 16% at 10% moisture content of the final product, since the processing scheme of prepress broths is excluded in the block type design. Steam consumption in the production of flour averages 170 kg / hr or 520 kg per tonne of processed raw materials, energy consumption is 2.3 kW per tonne of raw material.

 The achieved plant productivity when working on shell-containing raw materials in the specified configuration was 500-600 kg / day for finished products or 2.5-3 tons / day for raw materials, which amounted to 30-35% of the estimated capacity. This is due to the need for the raw materials to pass slowly through the grinder, and the press to prevent the pressing of raw materials and the formation of impassable blood clots, which leads to equipment failure. But even with this kind of installation operation, a residual moisture content of 12% is unattainable. It is really possible to get products with a residual moisture content of 19-22% in a continuous mode.

 The problem solved by the invention is to increase the productivity of the process of obtaining crab grains and crab flour due to the implementation of the process in a continuous mode, reducing the cost of the method of obtaining final products while increasing their techno-chemical parameters.

 The essence of the proposed method is as follows.

Carapace-containing food waste from crab production, including cephalothorax, abdomin, substandard limbs and waste from the crab-canning industry, is thawed, washed with sea water and dried in two stages. Pre-drying is carried out until the residual moisture content in the feed is in the range of 50 - 55% at a continuous feed rate of 0.45 - 0.55 t / h, until the temperature of the feed at the exit of the pre-drying device is 35 - 40 ^o C, at maintaining the temperature in the vest space of the preliminary drying device 80-90 ^o C, and forced removal of moisture by air with a temperature of 10 - 20 ^o C with a speed of its advance equal to 1850 - 2750 m ³ / hour. The second stage of drying is carried out until the residual moisture content in the product is not more than 12% while maintaining the temperature of the raw material at the outlet of the drying apparatus equal to 60 - 90 ^o C, the temperature in the outside cavity of the drying apparatus equal to 90 - 100 ^o C, and the countercurrent air speed with a temperature of 100-130 ^o C, equal to 2250 - 2750 m ³ / hour. Dry raw materials are crushed to a ratio of grains: flour, equal to (80-85) :( 15-20), and divided into vibrating sieve into crab grits and crab flour. Finished products are packed in bags with a capacity of 25 - 30 kg.

In contrast to the prototype, the cooking stage is excluded from the technological process, which minimizes protein losses and concentrates protein in flour, avoiding the formation and disposal of prepress broth; reduced time of temperature effects on raw materials due to the fact that the process is carried out continuously. The total heating time of the raw material during drying, on average, is no more than 1.5 hours, and high-temperature heating is about 1.25 hours (versus 3-5 hours in the prototype); at the pre-drying stage, forced steam removal was used by an exhaust ventilation system at a speed of 1850 - 2750 m ³ / h without the formation of rarefaction zones, which eliminates the risk of raw materials being welded in the condensate formed, significantly reduces the temperature of the raw material processing, and eliminates the possibility of local overheating of chemically heterogeneous raw materials its sticking to the details of the apparatus during transportation.

 Mild processing and drying modes of the raw materials in the proposed method contribute to a greater extent, compared with the prototype, the preservation of the native properties and structure of chitin. A comparison of the physico-chemical characteristics of chitosans obtained according to TU 15-01 from dry grains produced by the proposed method and the prototype method indicates a higher molecular weight of the polymer, the viscosity of its one percent solution in acetic acid (30-40%) in the case of raw materials, obtained by the proposed method. The method also provides obtaining crab flour with a high (at least 55%) protein content and preserving the native properties of carotenoid pigments, which significantly increases the value of flour as a feed product.

 New in the method is the deep washing of raw materials with sea water after thawing, which makes it possible to level the differences in the composition of the raw materials used as a complete complex of crab production wastes caused by the difference in conditions, methods and modes of its procurement and the inconstancy of its chemical composition. Washing the raw materials with sea water allows emulsifying and removing residual hepatopancreas lipids, the absence of which determines the quality and drying efficiency; eliminates the need for antioxidants; allows you to compensate for the effect of the proteolytic enzymes of hepatopancreas, as a result of violations of the pre-treatment of raw materials, if any.

Also new in the method is the temperature of the raw material during preliminary drying, equal to 35 - 40 ^o C, necessary to release occlusive moisture from the polymer-mineral structure of the material and to prevent unwanted swelling of chitin-containing raw materials with the moisture content in it that takes place on stages of preliminary drying. Non-swollen, unheated raw materials are less viscous, better transported by auger, and quickly lose moisture at the stage of final drying.

The removal of excess moisture at the stage of preliminary drying with air with a temperature of 10-20 ^o C, passed through the pre-drying device at a speed of 1850-2750 m ³ / h, allows you to not raise the temperature of the raw material above 40 ^o C and reduce the residual moisture content at this stage to 50 - 55%.

In the second stage of drying, the temperature of the raw material varies from 35 - 40 ^o C at the inlet to 60-80 ^o C, maximum 90 ^o C, at the outlet. The temperature regime of the process is maintained by supplying steam to the mesenteric space and the hollow shaft of the apparatus to maintain the temperature in it 90-100 ^o C and counter-flowing air with a speed of 2250-2500 m ³ / h with a temperature of 100-130 ^o C supplied to the top of the dryer apparatus for maintaining a constant temperature of the walls and disks of the worm part of the drying apparatus. The temperature of countercurrent air in the range of 100-130 ^o C allows to achieve drying efficiency to a residual moisture content of the product at the output of not more than 12% and to prevent overheating of the inner surface of the drying apparatus and a decrease in the quality of products. The counterflow air feed rate provides effective moisture removal with a constant vapor temperature of not higher than 90 ^o C and the yield of final products with a residual moisture content of not more than 12%.

 The ratio of grains: flour in the crushed product, equal to (85-80): (15-20), provides the maximum concentration of the basic components in both products: chitin - in grains (up to 32 - 34%), protein - in flour (up to 55- 60%).

 To implement the method, a line is proposed consisting of a storage hopper (1), a conveyor belt (2), a gooseneck conveyor (3), a hopper with a screw batcher (4) with a speed variator, and a preliminary drying device (5) connected by a pipeline with an exhaust fan (6), a drying apparatus (7) connected to a heater (8) and a fan (9), a mill unit (10), a pneumatic conveyor (11), a cyclone (12) with a unloader and a screw feeder, a vibrating screen (13) , bag holder (14), control and weighing device (15) (drawing).

 The proposed method, implemented on the presented production line, allows to achieve an output of dry products (flour and grains) on average 22% with a residual moisture content of 12% (or in terms of 10% humidity, the average yield is 19.4%), increase productivity lines to 10.5 tons / day, reduce production energy consumption to 12-14 kWh (to 1.2-1.4 kW per ton of processed raw materials), and reduce steam consumption to 130 kg / hour (or 350 kg per ton of processed raw).

 The invention is illustrated by examples.

 Example 1

5 tons of ice cream block shell-containing raw materials are placed in a storage hopper. The bunker is filled with sea water or water from the refrigeration system of the refrigerator installation. Raw materials are defrosted to complete "scattering" of blocks, approximately 3-6 hours. The temperature of the defrosted raw material is 1-2 ^o C. After this, the shell-containing raw materials are washed off with a jet of seawater onto a conveyor belt through a gate located in the lower part of the bunker, during which they are washed with a large amount of clean sea seawater. Raw materials are dumped onto the goose-neck conveyor, through which it is fed into the hopper with a screw batcher, which has a gap between the sheets of the bottom 2-3 mm in the lower part to discharge free moisture as a result of tedding. Moisture loss is 3-5%. From the hopper with a screw metering device at a speed of 0.55 t / h, raw materials are fed to a preliminary drying and heating unit of raw materials, to which a pipeline of a vessel’s exhaust fan is connected, which allows air to be pumped through the preliminary drying device in a volume of 2250 m ³ / hour. In the device, the raw material is heated to a temperature of 40 ^o C with deaf steam supplied to the foreign space of the apparatus under a pressure of 3-3.5 kg / cm ² to reach a temperature of 80-90 ^o C. The temperature of the exhaust vapors is 60 ^o C. Heated and dried to a residual moisture content of 53%, the raw materials are conveyed by a screw conveyor into the drying apparatus. The drum of the drying apparatus is heated by steam supplied into the stump space under a pressure of 3.5-4 kg / cm ² until it reaches a temperature of 90-95 ^o C. Toward the movement of raw materials, hot air is pumped into the dryer, pumped by a fan heater with a temperature of 120 ^o C speed of 2500 m ³ / hour. The temperature of the exhaust vapors during drying is 80 ^o C. The residual moisture content of the dried raw materials is 12%. At the outlet of the dryer, dry raw materials are captured by the air stream generated by the mill fan and fed to the mill for grinding. The required ratio of product yields is achieved by installing in the mill the control sieve of maximum grinding with a mesh size of 5 mm and setting the number of grinding hammers of the mill installation equal to 6. The crushed raw material is transferred via a pneumatic conveyor to a cyclone. From the cyclone with a screw feeder, the crushed dried raw material is fed to a vibrating screen, structurally made in the form of a gutter equipped with a perforated false bottom with a perforation hole diameter of 1 mm and located at an angle of 15 ^o , providing a separation efficiency of at least 98% at a separation speed of up to 100 kg of dried products in hour. On a vibrating screen, crab grains are separated, consisting of particles with a granule size of more than 1 mm and enriched with chitin from crab flour (granule size less than 1 mm), enriched with protein. Crab grits and crab flour are packed in bags and transferred to storage in a dry ventilated room. The yield of grains is 935 kg (18.7%), the yield of flour is 165 kg (3.3%). The total yield of dried products is 22%. The ratio of grains: flour is 85: 15. The products obtained are a material uniform in size characteristics, in the bulk of the orange-red color with a characteristic odor, without discrediting signs. The protein content in crab meal is 57.8%.

Example 2. Analogously to example 1, from 5 tons of raw materials with a feed rate of 0.45 t / h, an exhaust fan capacity of 1850 m ³ / h, countercurrent drying air temperature of 130 ^o C and a feed speed of 2250 m ³ / h, 940 kg are obtained (18.8%) crab groats and 160 kg (3.2%) crab flour. The protein content in crab meal is 60.2%.

Example 3. Analogously to example 1, from 5 tons of raw materials with a feed rate of 0.5 t / h, an exhaust fan capacity of 2050 m ³ / h, countercurrent drying air temperature of 100 ^o C and a feed speed of 2500 m ³ / h, cutting temperatures spaces in the pre-drying device and the drying apparatus, respectively 80 and 90 ^o C receive 930 kg (18.6%) of crab grains and 170 kg (3.4%) of crab flour. The protein content in crab meal is 55.4%.

Example 4. Analogously to example 1, out of 5 tons of raw materials with a feed rate of 0.55 t / h, an exhaust fan capacity of 2250 m ³ / h, countercurrent drying air temperature of 110 ^o C and a feed speed of 2500 m ³ / h, chopping temperature spaces in the drying apparatus 100 ^o C receive 938 kg (18.8%) of crab grains and 167 kg (3.3%) of crab flour. The protein content in crab meal is 58.6%.

Claims (3)

1. A method of processing waste from crab production to obtain a finished product with a moisture content of not more than 12%, including thawing raw materials, washing with sea water, drying in two stages, grinding dried, separation and packaging of finished products, characterized in that after thawing, the raw materials are washed with marine water, drying is carried out in a continuous way, while preliminary drying is carried out until the moisture content of the raw materials is 50 - 55% at a feed rate of 0.45 - 0.55 t / h, while maintaining the temperature inside the feed at an output of 35 - 40 ^o C and at forced moisture removal by air with a temperature of 10 - 20 ^o C with a speed of its movement through the preliminary drying device equal to 1850 - 2750 m ³ / h; the second stage of drying is carried out until the temperature of the raw material changes from 30 - 40 ^o C at the beginning of drying to a temperature of 60 - 80 ^o C at the end of drying and the speed of counterflow air with a temperature of 100 - 130 ^o C equal to 2250 - 2500 m ³ / h.  2. The method according to claim 1, characterized in that the grinding of dried is carried out to a ratio of grains: flour, equal to (80 - 85): (15 - 20).  3. A line for the production of crab grains and crab flour from crab production waste, including a storage hopper, a conveyor belt, a gooseneck conveyor, a hopper with a screw dispenser, a drying apparatus, a mill, a cyclone equipped with a unloader and a screw feeder, a bag holder and a weighing machine -control device, characterized in that between the conveyor and the drying apparatus there is a preliminary drying device connected by a pipeline to an exhaust fan, the drying apparatus is connected by a pipeline and a fan heater, and between the cyclone and meshkoderzhatelem set vibrating.

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