Soybean Meal Fermentation & Drying Technology and Equipment

With the increasing popularity of feedstuff fermentation technology in China, the feed industry and breeding industry have put forward new requirements on the output and quality of fermented raw materials. The reliability of the fermentation raw materials production technology and equipment plays a decisive role in the quality.

The moisture content of feedstuff after solid-state fermentation is normally about 40%, and it’s easy to deteriorate if improperly preserved. In addition, in the industrial production of feedstuff, it’s difficult to add wet materials to the feed production stage automatically. Therefore, most manufacturers of fermentation feedstuff need to adopt drying equipment to reduce the moisture content of feedstuff to be less than 13% for storage and transportation while ensuring its stability and quality.

1. Soybean Meal Fermentation Process

The process of soybean meal solid fermentation can be briefly described as follows. Feed the strain to the raw materials and then add water for mixing until the moisture content of the fermentation materials is about 40%. Then, feed the material into fermentation equipment for solid-state fermentation, which generally lasts 2 to 4 days. After fermentation, drying the materials until the final product moisture content is not higher than 10%, then grind and pass through a 20~40 mesh sieve, and finally packaged. Traditional solid-state fermentation equipment tends to require a large amount of labor. Since the low level of automation, it is unsuitable for continuous production. Current intelligent solid-state fermentation equipment can automatically feed and discharge. The discharge is uniform and stable, and the back end can be connected with the drying system seamlessly, bringing products with excellent and stable quality and good fermentation effects.

2. Current Situation of Solid-state Fermentation Equipment

At present, solid fermentation equipment in the industry mainly includes ground stacking fermentation, ton bag fermentation, above-ground tank fermentation, box fermentation, plastic bag fermentation and underground pool fermentation. Most such equipment has the following problems: low automation, requiring a large amount of labor; poor sanitary conditions, cross-contamination; being difficult to guarantee fermentation conditions; no large-scale and continuous production, if not controlled correctly, it’s likely to be counterproductive in the fermentation process (infected with bacteria and go moldy, produce toxins, etc.). However, the intelligent fermentation equipment has the following characteristics: continuous and scale production; automatic and intelligent operation; the fermentation environment is controllable to ensure the fermentation conditions; good sanitary conditions without cross-contamination and well-cleaned equipment; energy-efficient running which will reduce fermentation costs; fermentation and drying equipment is environmentally friendly.

3. Intelligent Fermentation Equipment

3.1 Automated rectangular fermentation bed (facultative aerobic)

The materials are fed into the distributing machine by air, and then inoculated in the inoculation mixer, and finally be distributed; the fermentation bed has the auxiliary heating function, which is generally used for facultative or anaerobic fermentation; the bed thickness is usually 700 ~1,000 mm and it can be appropriately adjusted according to the actual production conditions; automatic feeding and material tumbling is realizable in the production process; after fermentation, the discharging is automatic, continuous, quantitative, uniform and stable discharging, and the back end can be seamlessly connected with the drying system.

3.2 Round fermentation tower

It’s generally adopted for facultative or anaerobic fermentation, and is for high bed fermentation; the maximum bed thickness is 2,000 mm and it can be appropriately adjusted according to the actual production conditions; automatic feeding and discharging is realizable in the production process, and the discharging is continuous, quantitative, uniform and stable discharging, and the back end can be seamlessly connected with the drying system. Good anaerobic fermentation environment and excellent fermentation effects generate stable products. The capacity is 50~100T/batch.

3.3 Rectangular aerobic fermentation bed

The fermentation machine can automatically adjust the temperature, humidity and ventilation quantity to control the fermentation process. The inoculated materials are fed into the fermentation machine, the bed thickness is usually 300~450 mm and it can be appropriately adjusted according to the actual production conditions; the machine is specially designed for shallow bed fermentation; automatic feeding and material tumbling is realizable in the production process; after fermentation, the discharging is automatic.

3.4 Round fermentation machine (aerobiotic)

The fermentation machine can automatically adjust the temperature, humidity and ventilation quantity to control the fermentation process. The inoculated materials are fed into the fermentation machine, the bed thickness is usually 300 ~500 mm and it can be appropriately adjusted according to the actual production conditions; the machine is specially designed for shallow bed fermentation; automatic feeding and material tumbling is realizable in the production process; after fermentation, the discharging is automatic.

4. Drying Equipment

4.1 Shell and tube dryer

Steam is in the tube pass and materials contact with the shell pass, and the materials are scattered by the shovelling plate, transported and dried in the dryer. The dryer has the following advantages: single equipment has large capacity, high efficiency and energy saving, low steam and electricity consumption for per ton of materials, continuous production.

4.2 Live drying tower

The bed thickness is adjustable and the materials inside are in fluidized state and fully contact with hot air, which will generate a flash evaporation effect. The materials can be dried in the low temperature and continuous production and energy-saving are realizable.

4.3 Combined drying

Combining the tube bundle dryer with the live drying tower: most water is removed from the materials in the tube bundle dryer, and then the materials are fed into the live drying tower for secondary drying, which fully takes advantage of the two machines, resulting in energy-saving and low-temperature drying.

4.4 Circulation drying at low temperature

Large air volume, quick flash evaporation, and the low-temperature drying will ensure the material activity to the most extent, and it can realize the drying of viscous materials and meet the need for large capacity of single equipment.