Notes

What affect the molding result of biomass pellets?<br>
Biomass energy has several application settings, such as biogas, alcohol, and biomass molding gas. Biomass molding fuel is one of the most practical and economical setting. Biomass molding gas has biomass pellets as well as biomass briquettes 2 types. Biomass pellets gradually replace briquettes owing to tiny dimension, high density, as well as very easy usage.



Biomass briquettes and biomass pellets

Biomass pellets are made from timber pellet maker. It uses high pressure from roller and also die to mold biomass products into high-density solid pellets. The molding impact is influenced by the resources high quality, molding procedure, as well as equipment efficiency. To boost the molding results of biomass pellets, you need to discover the following variables.



Resources quality

Raw material composition

The raw materials for making timber pellets are composed of different components. They have various reactions in high warm and also high pressure. Some materials like healthy proteins and lignin will certainly soften and have gluing effect. Some materials like cellulose as well as not natural particles are difficult to break down or split. They impede the molding of timber pellets, yet they occupies the most part of biomass materials



The make-up of raw materials has the biggest influence on the pellet durability. The adhering to chart reveals the Pellet Quality Coefficient (PQF) of a number of usual raw materials



The bigger the PQF, the tighter the timber pellets are bound. Some products like bentonite, lignin have high PQF. They can act as binders. Some products like acid oil has low PQF, the fragments inside can't bind together properly. Loose biomass pellets has much less sturdiness. Only when the total PQF of all materials amount to more than 4.7, the timber pellets can materialize successfully.



The fineness of raw materials.

Raw materials with smaller sized granularity have bigger surface, so they are simple to bind. As well as the generated pellets are a lot more small and smooth, challenging to damage. The smaller sized the granulates, the higher the wood pellet strength. But as well tiny granulates requires high power consumption for pulverizing. It is not suggest to pursue also little granulates.



The granulates should be uniform in dimension. Also large granulates are challenging to bind with others, and the surface area have a tendency to be rough. Big bits normally cause glowing split, where the wood pellets are easy to damage. Too huge granulates are hard to get into the die holes. They will certainly aggravate the abrasion of pellet mill die as well as roller, reduce the wood pellet production, as well as reduced the molding price.



Therefore, the granularity of basic materials need to be 1/2 -2/ 3 of the wood pellet dimension. ecostan pellet machine can adopt a screener with the pore size less than 10mm in pulverizing procedure, so that the raw products can satisfy the standard for pelletizing as well as blending, as well as decrease the power usage and also tools abrasion.



The dampness of basic materials.

The dampness in the biomass products have lubrication feature. They can lower the rubbing between the granulates, and also enhance their bonding. The wetness can likewise soften the materials to make sure that they are less complicated to warp and also mold.



Biomass materials varies in dampness material, usually between 8% -15%. The wetness is affected by temperature. For those products with over-high moisture, we need to dry them prior to making pellets.



Molding procedure

The molding temperature level

The biomass molding is to make the organic parts of biomass soften, bond as well as changed under high temperature and pressure.



Usually, the raw materials soften at the temperature of 70 ℃ ～ 80 ℃, bond at the temperature of 160 ℃, melt at the temperature of 240 ℃. With the boost temperature, the raw materials end up being a lot more soften, the liquidity raises, the resistance between raw materials reduce, so they are less complicated to mold and mildew. As determined, the molding stress in high temperature is fifty percent of that in heat.



Heat is not constantly good. Over-high temperature level will trigger carbonization of the biomass materials. Such carbonization is neither uniform neither controllable, which will prevent molding and affect the wood pellet top quality.



The thickness of product layer

In pellet devices, there is a clearance between the roller and also die, where the biomass products create a layer. The clearance can be readjusted from 0.1 mm to 0.3 mm. To create small-size wood pellets, the clearance is tiny, and the other way around.



The thickness of material layer likewise affect the power usage of the pellet equipment. When the product layer is thick, the extrusion stress will enhance. With too much basic materials entering the die holes, they will be too limited to discharge, and also create damages to the equipment. When the material layer is also slim, the extrusion stress is little, the raw materials squeezed into the die holes want, so the timber pellet manufacturing is low.



The picture listed below programs the impact of resources on the extrusion pressure. B describes ideal thickness, A refers to the layer is also thick, C refers to the layer is as well slim. In richi machinery , the extrusion pressure boost a whole lot owing to the long squeezing location. In the C status, the extrusion force is as well little. So an ideal density is a premise of high-efficient manufacturing.



Equipment efficiency

Extrusion speed

Extrusion rate determines the time that basic materials remain in the die holes, so regarding affect the molding high quality. When the raw products leave in the die openings for short time, the system power intake is low, however the timber pellets might hang. When the raw materials leave in the die holes for long, the wood pellets will certainly have higher density and high quality, the unit power usage additionally raise.



If the raw products leave in the die openings for as well long, the rubbing will certainly be too expensive, the pellets will certainly be too dense, the pellet maker will certainly be warm as well as even quit.



The extrusion speed of a pellet machine is impacted by the roller size and rotating speed. A proper extrusion speed guarantee the devices work constantly with low power intake.



Extrusion toughness

The squeezing stress on the raw materials identifies the density of timber pellets. High pressure extrusion and also rubbing will soften as well as warp the raw products and bind them together.




If the extrusion strength wants, the raw materials can't be built efficiently. If the extrusion strength is expensive, it will intensify the abrasion of dies and also contribute to set you back.



The criteria of die opening

The criteria of die openings are restricted by raw material granularity, extrusion rate, extruding strength. Oppositely, the parameters of die holes affect the molding of wood pellets.



Pellet mill die openings have particular compression proportion. High compression ratio raise the extrusion stamina, lower the extrusion rate. They appropriate for the materials with reduced adhesive pressure.



The hole entrance form influence the speed of basic materials entering into the die holes, and affect the thickness of raw materials.



The specification of die holes ought to be changed according to various materials, to make sure that you can obtain high-grade wood pellets with low unit power consumption.

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