Aquaculture Feed Production Frequently Problems and Treatment Measures

In the daily production of aquatic feed, we have also encountered some problems from various aspects. We will now enumerate and communicate with you, as follows:

First, formula

1. In fish formulation structure, more raw materials such as oysters, cotton vines, etc. are all crude fibers. Some oil refineries are technologically advanced, and the oil is basically dried and the content is small. Moreover, in the production of such raw materials, it is not easy to absorb water, which has brought a lot of influence on the granulation. In addition, such as cotton peal difficult to crush, affect the efficiency.

2. Treatment measures: Increase the use of rapeseed cakes, add high-quality real estate raw materials such as rice bran to the formula, and add wheat with formula proportion of 5-8%. Through adjustments, from the perspective of the pelleting effect in 2009, it is more ideal and the ton output has also gone up. The 2.5mm pellets are 8-9 tons, which is nearly 2 tons higher than before. The appearance of the particles is also significantly improved.

In addition, in order to improve the efficiency of crushing the pupae, we mix and pulverize the pupae and the pupae in a 2:1 mix. After the improvement, the pulverization speed is basically the same as that of the pounded clams.

Second, the uneven surface of the particles

1, has a great impact on the appearance of the finished product, the other into the water easily collapsed, the utilization rate is low. The main reason is:

(1) The raw material is crushed too coarsely. During the process of tempering, it cannot be fully matured and softened, and it cannot be well combined with other raw materials when passing through the die hole.

(2) In the formulation of fishes with a large amount of crude fiber, bubbles are contained in the raw materials during the tempering process. When the particles are pressed, these bubbles collapse due to the pressure difference between the inside and the outside of the mold. Causes the surface of the particles to be uneven.

2. Treatment measures:

(1) Control the crushing process

At present, our company uses 1.2mm sifting powder for bulk raw materials in the production of fish feed, and controls the frequency of use of the sifter and the degree of wear of the hammer to ensure fineness.

(2) Control steam pressure

According to the recipe, the steam pressure can be reasonably adjusted during production, and the general control is about 0.2. Due to the large amount of crude fiber raw materials used in the formulation of fish, good quality steam and reasonable conditioning time are required.

Third, poor particle water resistance

1. This type of problem is the most common problem in our daily production. It is generally related to the following factors:

(1) Short tempering time, low tempering temperature, uneven or insufficient tempering, low maturation, and insufficient moisture.

(2) Insufficient adhesive raw materials such as starch.

(3) The compression ratio of the ring mode is too low.

(4) The fat content of the formulation and the proportion of crude fiber raw material are too large.

(5) Crush particle size factors.

2. Treatment measures:

(1) Improve the steam quality, adjust the blade angle of the conditioner, extend the conditioning time, and properly increase the moisture content of the raw material.

(2) Adjust formulas, increase starch raw materials appropriately, and reduce fat and crude fiber ratio.

(3) Add binder if necessary. (sodium bentonite pulp)

(4) Improve the compression ratio of the ring die (generally choose 11-13 in Hubei)

(5) Control the crushing fineness

Four, particles containing too much powder

1. It is difficult to guarantee the general appearance of the pellet feed after cooling and screening. The customer reflects more: Fine ash and powder in the pellet are more. From the above analysis, I think there are several reasons:

A. The surface of the granules is not smooth, the incisions are not neat, the loose particles are easy to produce powder, etc.;

B. The classification screen is not completely screened, the screen is clogged, the rubber ball is worn badly, and the screen aperture does not match;

C. There is more fine ash in the finished product warehouse, and the clearance is not complete;

D, packaging dust hidden dangers;

Treatment measures:

A. Optimize the formula structure, reasonably select the ring mode, and control the compression ratio.

B. During the granulation process, the time for conditioning and the amount of feeding and the granulating temperature are controlled so that the raw materials are fully matured and softened.

C. Ensure that the pellets have a neat section and use a soft knife made of strip steel.

D. Adjust and inspect the sizing screen. Use a reasonable screen configuration.

E. The secondary screening process under the finished product warehouse can greatly reduce the ratio of powders.

F, finished product warehouse, line cleanup should be timely, in addition, improve the packaged dust removal device is very necessary, it is best to use negative pressure for dust removal, ideal. In particular, during the packaging process, the packer must periodically perform a clean-up on the packed buffer bucket to remove dust.

Five, different lengths of particles

1, we often encounter in daily production, especially the 420 and above models, the control is more difficult, and its causes are summarized as follows:

(1) The feeding amount of granulation is not uniform, and the quenching and tempering effect fluctuates greatly.

(2) Inconsistent mold roll gap or serious wear of the ring mold and the press roll.

(3) Along the axial direction of the ring die, the discharge at both ends is less than the intermediate discharge rate.

(4) The ring mold relief hole is too large and the opening rate is too high.

(5) The position and angle of the cutter are not reasonable.

(6) Granulation temperature.

(7) Ring die-cutting blade type and effective height (blade wide and narrow) influence.

(8) At the same time, the distribution of raw materials in the pressing room is not uniform.

2. The quality of the feed and the quality of the pellets are generally analyzed from the intrinsic quality and external quality of the feed. As a production system, we are exposed to more of the external quality of the feed pellets. From the perspective of production, the factors affecting the quality of aquatic feed pellets can be roughly summarized as the following:

(1) The formula design organization has a direct impact on the quality of aquatic feed pellets, accounting for about 40% of the total;

(2) Crushing force and uniformity of grain size;

(3) The diameter, compression ratio, and linear velocity of the ring die affect the length and diameter of the particles;

(4) The compression ratio, line speed, quenching and tempering effects of the ring die and the effect of the cutter on the length of the particles;

(5) Raw material moisture, tempering effect, cooling and drying have an effect on the moisture and appearance of the finished product;

(6) The cause of the equipment itself, the reason of the process, and the effect of refining and tempering have an impact on the powder content of the pellets;

3, processing measures:

(1) Adjust the length, width, and angle of the cloth doctor blade and replace the worn doctor blade.

(2) Note that when the production is started and the production is almost completed, the position of the cutter must be adjusted in time due to the small amount of feed.

(3) During the production process, ensure that the feeding amount and steam supply are stable. If the steam pressure is low and the temperature is not up, adjust or stop the machine in time.

(4) Adjust the gap of the mold roll reasonably. Follow the new mold with the new roller, timely repair the pressure roller and ring die due to wear and tear.

(5) Repair the ring mold guide hole and clear the blocked mold hole in time.

(6) When ordering the ring mold, the compression ratio of the three rows of holes at both ends of the original ring mold may be 1-2 mm smaller than that in the middle.

(7) Using a soft knife, the thickness is controlled between 0.5 and 1 mm, as far as possible to ensure that the knife edge is sharp, so that it is in the tooth line of the ring die and the pressure roller.

(8) Make sure that the ring mold is concentric, check the gap of the main shaft of the granulator regularly, and adjust if necessary.

Six, summary control points:

1. Pulverization: Slurry fineness must be controlled according to specifications

2. Mixing: It is necessary to control the mixing uniformity of the raw materials to ensure the proper mixing amount, mixing time, moisture and temperature.

3. Curing: The pressure, temperature, and moisture of the extruder must be controlled

4. Size and shape of pellets: The die and cutter must be selected to the appropriate specifications.

5. Moisture of finished feed: The time and temperature of drying and cooling must be guaranteed.

6. Grease Spraying: It is necessary to control the precise amount of injection, the number of nozzles and the quality of the oil.

7. Screening: The screen size must be selected according to the material specifications.