Difference between feed pellet machine and wood pellet machine

Difference between feed pellet machine and wood pellet machine

Feed pellet machine is also named as pellet feed

mill, fodder pellet mill. It belongs to animal feed processing equipment, which can

directly extrude corn, soybean meal, rice husk, straw and grass into small pellets.
    1, Different Raw Materials
    Feed pellets are mainly made from corn meal, grass meal, straw meal, cottonseed meal,

soybean meal and rice husk etc. These materials are relatively soft and moist so they can

be processed directly with a small amount of liquid. When the pellets mill working, there

will be a heating process, after that, the feed pellets will be even more soft and smooth.
    Biomass pellets are made from more various and harder materials. Logs, wood chips,

waste wood, sawdust, sunflower stalk, cotton stalks, bamboo dust, coffee husk, wheat straw,

palm husk and almost all the biomass waste you can think of can be processed in to pellets.

Biomass pellets mills deal with raw materials contain more fiber, so the process is more

complex than making feed pellet mills.
    2, Different Shapes
    Because of the reason we mentioned above, feed pellet mills and biomass pellet mills

are different from the appearance. Generally speaking, feed pellet is smaller and thinner.

The largest feed pellet mill is about 1 meters high and weighed several hundreds kilograms.

While the smallest biomass pellets mill, for example, the wood pellet mill is more than 2

meters high and weighed around 5 to 6 tons. What’s more, biomass raw materials are hard to

process, so you may need a complete biomass pellet line to help you from chipping and

crushing the raw material till packing the pellets.
    3. Different Input Costs
    If it is a pellet production line with the same output, for example, the pellet

production line that is also 1t / h, the feed pellet production line with

feed

pellet granulator has a lower investment cost than the wood pellet production line.
    Richi machinery produces a variety of animal feed pellet machines and wood pellet machines. If you need a large

amount of pellets, you need to set up a pellet production line. We can provide you with a

complete solution from the early design to the later equipment installation and training.
    High quality pellets can withstand repeated handling as can occur during bagging,

transportation, storage, and moving in feed lines without excessive breakage or generation

of fine particles. Here we describe what factors influence the quality.
    Feed pelleting can be defined as conversion of finely ground mash feed into dense, free

flowing pellets or capsules, in a process that involves steam injection (moisture and heat)

and mechanical pressure. There are several advantages for feeding broilers pelleted rather

than mash feed. The main advantage is the improved bird performance (improved feed intake,

weight gain and feed conversion). Birds fed pelleted diets spend less time and need lower

maintenance energy requirements during eating and digestion in comparison to those fed mash

feed. The other benefits of feeding pelleted diets include increase feed density, decrease

feed dustiness, wastage and selection, better mechanical handling of feed on the feed

lines, and destruction of feed-borne pathogens. Therefore, the full genetic potentials of

modern broiler strains cannot be achieved without pelleted feed. In order to achieve these

multi-benefits, the pellet durability should be of a standard quality (not contain too much

fines), otherwise, the bird’s performance will be adversely affected.
    Pellet durability index
    High quality pellets can be defined as pellets that can withstand repeated handling as

can occur during bagging, transportation, storage, and moving on feed lines without

excessive breakage or generation of fine particles. Pellet quality is usually expressed as

the pellet durability index (PDI), and measured by using a tumbling can device, in which

the pellet sample to be tested is first sieved to remove fines, then tumbled in the

tumbling can device for a defined period of time. The tumbled sample is then sieved to

remove fines, and the amount of intact pellets is determined. The PDI can be calculated as

following: weight of intact pellet after tumbling / weight of intact pellet before tumbling

x 100. Other devices can be used to determine the pellet durability such as Holmen pellet

tester, lignotester, etc.
    Factors affecting pellet quality
    Several factors have an effect on the quality of the pellets. First of all the feed

formulation (raw materials and additives used). Some feed ingredients have a good impact on

pellet quality, while others could adversely affect the quality. Unfortunately, corn-soy

diets are not the ideal diets to achieve the desired pellet quality. Dietary inclusion of

wheat grain or wheat by products (wheat midds, wheat gluten) can increase pellet

durability, because of the high protein (gluten) and hemi-cellulose content of wheat in

comparison to corn or corn co-products. Similarly inclusion of oat as a partial substitute

of corn can increase pellet quality.
    We can rank feed grains according to their positive impacts on pellet quality from best

to worst as followings:
    oat,
    wheat,
    barley,
    corn，
    sorghum.
    It was previously known that starch and its gelatinisation is the most important factor

for achieving the desired pellet quality. However, recent reports indicated that the

positive impact of protein on pellet quality is much more important than that of starch.

Dietary inclusion of oil has an adverse effect on pellet quality. This is attributed to the

coating effect of oil to the feed particles which prevent their penetration by the steam,

also oil reduces the friction generated between die and feed particles with subsequent

decrease in the starch gelatinisation rate. Inclusion of binding agents (e.g. water

(simplest binder), lignin sulphonate, hemicelluloses extract, gelatin, etc.) and/or

surfactants can increase pellet quality, pellet throughput, and lower power consumption

(Table 2). The Feed pellet quality factor (FPQF) is a tool used to predict the pellet

quality of the feed formula. Estimation of the FPQF for certain feed formula: each feed

ingredient has a pellet quality factor (PQF). The PQF has a score from 0 to 10, where 0

predicts poor pellet quality and 10 good pellet quality. We can estimate the FPQF for each

ingredient by multiplying the PQF by the % of inclusion of the feed ingredient in the

formula (Table 1). The overall FPQF equals the sum of the FPQF of all ingredients used in

the formula. Generally, values below 4.7 are indicators for poor pellet quality, while

values higher that 4.7 are indicators for good pellet quality.
    Affect of ingredient particle size and grinding on pellet quality
    The second factor influencing feed

pellet line quality is the feed ingredient particle size. Although doubted by some

researchers, it is accepted that decreasing ingredient particle size has a good influence

on pellet quality. However, over grinding is not recommended to avoid power wastage,

reduced production rate and suboptimal gizzard development. On the other hand, coarse

grinding eases pellet break down and decreases starch gelatinisation (high degree of

gelatinisation is required to produce good pellets).
    Affect of steam on pellet quality
    Processing obviously has a large effect on pellet quality as well. When mash feed

passes through the conditioner, it is exposed to high pressure steam. This steam provides

the heat and moisture required for starch gelatinisation, particles adhesion, feed semi-

digestion, and feed pathogens damage. The steam temperature and the time that mash feed

stays in the conditioner have major influence on the durability of the produced pellets.

Conditioning the feed at a temperature of 80° C is sufficient to produce good quality

pellets. The minimum time that feed should stay in the conditioning tube to produce durable

pellets is 30 seconds. Long time conditioners, in which the feed can stay in the

conditioner for about 3-4 minutes, can be used to improve pellet stickiness.
    Thicker dies have positive impact on pellet durability
    Also die/roll specifications should be kept in mind. Pellets are produced via roll

pressing of the hot mash against metal die. Thicker dies (long die channels) have a

positive impact on pellet durability due to increasing the friction time between feed

particles and die wall with subsequent more starch gelatinisation. Most of starch

gelatinisation occurs when feed passes through the dies. A similar result can be obtained

by using small hole dies. This means that dies of 60 mm thickness are better than those of

50 or 40 mm thickness, and that dies with holes of 3 mm diameter are better than those with

holes of 5 mm diameter. However, using thicker or small holes dies have negative impact on

pellet throughput. Additionally, increasing the distance between roll and die from 0.1 to 2

mm resulted in an increase in the pellet durability.
    The cooler should be taken into consideration.
    After leaving the pellet mill, the temperature

of the pellets ranges from 70-90° C and the moisture from 15-17%. Proper cooling (via a

stream air cooling machine) is required to lower pellet temperature to about 8° C above

the ambient temperature, and moisture % to be 12%. The cooling machine can be either a

horizontal or vertical type. Quick cooling leads to removal of more moisture and heat from

the surface of the pellets than their core, and the resultant pellets will be brittle. On

the other hand, prolonged cooling produces very dry pellets that can be exposed to abrasion

and can be of low palatability.
    Conclusion
    Pellet quality can be influenced by several factors, including the ingredients, diet

formulation and processing. A good rule of thumb is the pellet quality factor (PQF), that

each feed ingredient has. The PQF has a score from 0 to 10, where 0 predicts poor pellet

quality and 10 good pellet quality. From experience we know that starch and its

gelatinisation is the most important factor for achieving the desired pellet quality.

However, recent reports indicated that the positive impact of protein on pellet quality is

much more important than that of starch.