A low-temperature desolventization process for soybean meal

Abstract

The invention relates to a low-temperature desolventization process for soybean meal, which comprises the following steps in sequence: (1) In the upper layer of the flash desolventization section, the high-solvent content meal with a solvent content of 30% and a temperature of 50°C is uniformly contacted with a superheated solvent vapor of 150-160°C After heat exchange, it becomes a low-soluble meal with a solvent content of less than 15%; (2) The low-content meal enters the lower layer of the flash desolventization section and continues to contact with the superheated solvent steam evenly to exchange heat, so that the content of the flash desolvent meal is reduced to Below 1%, the temperature rises to 80-85°C to become medium-temperature meal; (3) The medium-temperature meal enters the vacuum desolvation section of -2000--3000mm water column downwards, and performs indirect heat exchange with the steam heating interlayer layer by layer during the downward flow process , the lower part of the vacuum desolventization section is sprayed with superheated steam for short-term stripping, the solvent concentration of soybean meal is reduced to below 1000ppm, and it becomes a desolventized meal at 60°C~65°C; The cold air is used for drying and cooling, and the desolventized meal is cooled to room temperature, with a moisture content of 8%, and is discharged as a finished meal. The process has large output, high production efficiency and low energy consumption.

Description

Technical field [0001] The invention relates to an edible soybean meal processing technology, in particular to a low-temperature desolventizing process for soybean meal. Background technique [0002] Natural soybeans are extremely rich in plant protein, of which water-soluble protein has the highest content. Because protein is easily denatured by heat, the use value of soybean meal is greatly reduced. Low-temperature desolventization at a temperature lower than the denaturation temperature of the protein (80°C) can keep the water-soluble protein in the soybean meal at a higher content. Low-temperature dehydrated soybean meal, commonly known as white soybean flakes, is an important intermediate product for processing edible soybean protein. After deep processing, it can be made into various soybean protein products, such as protein concentrate, protein isolate, tissue protein and other functional soybean protein. Low-temperature desolventization can remove the solvent most thoro...

AI Technical Summary

Problems solved by technology

[0004] The traditional desolventizer has the following disadvantages: 1. There are only two precipitating chambers, and it is difficult for the solvent vapor to form a concentration gradient in the closed chambers of cylinder A and cylinder B. The diameter of the cylinder is large, and the solvent with high temperature and low density The steam is easy to short-circuit and circulate along the top area, and it is discharged out of the heat exchange chamber without sufficient heat exchange, resulting in incomplete desolventization; the white bean chips discharged from the B cylinder have high residual solvents, and the gaps of the white bean chips contain a large amount of solvent vapor that cannot be recovered , can only diffuse into the atmosphere

[0005] 2. The solvent air flow can only contact the surface material and the raised material, most of the material is accumulated at the bottom of the cylinder, without heat exchange; the desolvated wet meal is accumulated at the bottom of the cylinder, the bulk density is high, and the materials are sheared under forced stirring Cutting and extrusion will increase the powder degree and reduce the quality of the output

[0006] 3. The discharge temperature of white bean slices is 60-62°C, rich in water vapor, easy to condense and form water agglomeration, which will increase the powder degree during the transportation process, resulting in a decrease in the yield of qualified products

[0007] 4. The heating time is long, and the total heating time in cylinders A and B reaches 25-30 minutes. Long-term heating will reduce the content of soluble protein and reduce the quality of the output.

[0008] 5. The system integration is not high, the function of a single device is single, and the low-temperature desolventization process of A and B cylinders has been finalized, so it is difficult to improve

[0009] If the C cylinder is improved to further desolventize, the amount of solvent recovery can be increased and the solvent consumption can be reduced, but key indicators such as white bean flakes powder degree and NSI (nitrogen solubility index) will decrease, and the quality of the product will decrease, resulting in a decrease in economic benefits

In addition, it will increase equipment and site investment, increase operating costs and production costs, so the necessity of increasing the C cylinder is not appropriate in terms of income

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