TWI900361B - Method for producing biomass pellet fuel using bamboo materials - Google Patents

Abstract

A method for producing biomass pellet fuel from bamboo materials includes a crushing step of crushing bamboo waste into a plurality of process materials with a predetermined particle size or less; a crushing step of introducing the process materials into a water-washing and pulverizing device to form a plurality of powder materials to be molded with a production particle size smaller than the predetermined particle size; a drying step of introducing the process materials into a drying device to dry them to a humidity of less than 15%; a pelletizing step of uniformly mixing the powder materials to be molded with an oil and a plurality of sawdust chips in a pelletizing device to form a plurality of biomass pellet fuels; and a cooling step of cooling the biomass pellet fuels to a temperature of 25-30°C. In response to the characteristics of bamboo waste, a specialized process is provided to convert bamboo waste into biomass pellet fuel.

Description

Method for producing biomass pellet fuel using bamboo materials

The present invention relates to a method for producing fuel, and more particularly to a method for producing biomass pellet fuel using bamboo materials.

Energy demand is increasing worldwide, but the inevitable economic activities associated with energy consumption also generate significant amounts of waste. Therefore, to address both waste and energy issues, the environmentally friendly concept of "waste-to-energy," where waste is converted into fuel, has gained momentum. While many types of waste can be converted into fuel, bamboo, a material frequently used in daily life and easily generated in significant quantities in economic activities, lacks a dedicated, proven technology for its conversion into energy.

Furthermore, while bamboo's calorific value rivals that of wood, it contains higher levels of potassium and chlorine. Potassium forms low-melting-point potassium salt compounds during combustion, which can easily cause ash melting and increase the risk of clogging combustion equipment. Chlorine, when combined with other elements such as potassium and sodium, can form harmful chlorides such as hydrochloric acid. These compounds, in addition to potentially corroding equipment, also pose a high risk of other pollution. Therefore, converting bamboo waste into energy requires careful planning and proper disposal methods.

Therefore, the purpose of the present invention is to provide a method for producing biomass pellet fuel from bamboo materials by "turning waste into energy".

The present invention discloses a method for producing biomass pellet fuel from bamboo, comprising a crushing step of crushing bamboo waste into a plurality of process materials having a predetermined particle size or less; a crushing step of introducing the process materials into a water-washing and pulverizing device to form a plurality of powder materials to be molded having a production particle size smaller than the predetermined particle size; a drying step of introducing the powder materials to be molded into a drying device to dry the powder materials to a humidity of 15% or less; a pelletizing step of uniformly mixing the powder materials to be molded with an oil and a plurality of sawdust chips in a pelletizing device to form a plurality of biomass pellet fuels; and a cooling step of cooling the biomass pellet fuels to a temperature of 25-30°C.

The present invention utilizes a water-washing mechanism during the pulverization step to remove harmful inorganic salts containing potassium, chlorine, and other harmful substances from discarded bamboo, taking advantage of the distinct properties of discarded bamboo compared to wood or other materials. Under appropriate humidity parameters, the waste bamboo can be mixed with the oil and sawdust to form a pelletized material, which can then be used to produce the biomass pellet fuel. Subsequent combustion also reduces the production of harmful substances such as hydrochloric acid and dioxins (1,4-dioxin). This technology effectively addresses the need to "convert waste bamboo into energy" and provides a specialized technical approach.

Referring to Figure 1, an embodiment of the present invention's method for producing biomass pellet fuel from bamboo materials is shown. This method primarily utilizes bamboo waste as the primary raw material. The waste can be selected from bamboo processing waste, leftover bamboo materials, or any combination thereof. This embodiment includes a crushing step 11, a pulverization step 12, a drying step 13, a pelletizing step 14, a cooling step 15, a screening step 16, and a recycling step 17. The screening step 16 and the recycling step 17 can be performed after the cooling step 15; there is no specific order in which they should occur.

In the crushing step 11, considering the different sizes of the bamboo waste, in order to match the specifications of the subsequent equipment and ensure smooth process operation, the bamboo waste is crushed into a plurality of process materials with a predetermined particle size of less than or equal to 30 mm.

In the pulverization step 12, the process material is introduced into a water-washing pulverization device to form a plurality of pre-molded powders with a production particle size smaller than the predetermined particle size. The production particle size is 6 mm or less to accommodate the specifications of a subsequent granulation device. The water-washing mechanism not only further refines the material through pulverization but also dissolves soluble inorganic salts, such as potassium and chlorine, from the process material. This prevents the subsequent combustion of the fuel from generating harmful substances such as hydrochloric acid and dioxins (1,4-dioxin).

The drying step 13 involves introducing the powder to be molded into a drying device and drying it to a humidity of less than 15%. The drying device is preferably a drum-type drying oven that introduces a hot air flow. The drum's rolling motion stirs the material, ensuring that the introduced powder is dried evenly.

The pelletizing step 14 involves uniformly mixing the powdered material to be molded with an oil and a plurality of sawdust chips. The mixture is then pelletized into a plurality of biomass fuel pellets in a pelletizing device. Specifically, the pelletizing device is a ring die pelletizer. Each biomass fuel pellet is cylindrical in shape, with the cylindrical shape typically being 6-25 mm in outer diameter and 3-50 mm in length, based on commonly used market specifications.

After pelletizing, the biomass fuel pellets are still at a high temperature due to the effects of the pelletizing process. Their structure is not yet fully solidified, making them fragile. Therefore, the cooling step 15 cools the biomass fuel pellets to a temperature of 25-30°C, allowing them to stabilize and solidify, making them easier to package. It is worth noting that, in response to the high proportions of potassium and chlorine contained in bamboo materials, this embodiment has already significantly removed these potassium and chlorine components through a water washing mechanism in the pulverization step 12. As a result, the ash melting point of the produced biomass pellet fuel is significantly improved, resulting in higher combustion efficiency. Furthermore, by avoiding the generation of components such as hydrochloric acid and dioxins, corrosion of combustion equipment is reduced, and pollutant emissions during combustion are significantly reduced.

Since some unformed dust and debris are inevitably present in the granulation equipment, to ensure complete utilization of the raw materials, the screening step 16 removes the dust and debris that were unformed in the granulation step 14. The remaining powder to be formed is then reintroduced into the water-washing pulverization equipment, where the process continues with the pulverization step 12.

In the recycling step 17, a portion of the biomass pellet fuel produced is used as fuel for a gasifier. This ensures that the biomass pellet fuel's calorific value is fully utilized through the gasifier. The high-temperature gas stream generated after gasification can be directly introduced into the drying equipment for the next stage of the process, the drying step 13. By weight, only 6.0-8.0% of the produced biomass pellet fuel is sufficient to serve as fuel for the gasifier. In other words, as long as a small portion of the biomass pellet fuel produced in the recycling step 17 is captured, the biomass pellet fuel can be continued to be produced under the condition of a safe supply of raw materials. By recycling the produced fuel, the environmental protection concept of converting bamboo waste into energy is fully implemented.

In summary, this embodiment of the present invention's method for producing biomass pellet fuel from bamboo provides a specialized technical solution for converting waste bamboo into energy. This not only ensures stable production of the biomass pellet fuel, making it less likely to produce harmful substances after combustion, but also allows a portion of the produced biomass pellet fuel to be reused as fuel in the subsequent drying step 13 through the recycling step 17, further fully implementing the environmentally friendly concept of converting waste into energy and recycling. Therefore, the purpose of this invention is truly achieved.

However, the above description is merely an example of the present invention and should not be used to limit the scope of the present invention. All simple equivalent changes and modifications made within the scope of the patent application and the contents of the patent specification of the present invention are still within the scope of the present patent.

11: Crushing step 12: Grinding step 13: Drying step 14: Granulation step 15: Cooling step 16: Screening step 17: Recycling step

Other features and benefits of the present invention are clearly illustrated in the accompanying drawings, including: Figure 1 is a block diagram illustrating an embodiment of the present invention's method for producing biomass pellet fuel from bamboo.

11: Crushing Step

12: Crushing Step

13: Drying step

14: Granulation step

15: Cooling down step

16: Screening step

17: Recycle steps

Claims (10)

A method for producing biomass pellet fuel from bamboo materials comprises: a crushing step of crushing bamboo waste into a plurality of process materials having a predetermined particle size or less; a pulverizing step of introducing the process materials into a water-washing pulverizing device to form a plurality of pre-molded powders having a production particle size smaller than the predetermined particle size; a drying step of introducing the pre-molded powders into a drying device to dry them to a humidity of less than 15%; a granulating step of uniformly mixing the pre-molded powders with an oil and a plurality of sawdust chips, and granulating them in a granulating device to form a plurality of biomass fuel pellets; and a cooling step of cooling the biomass fuel pellets to a temperature of 25-30°C. The method for producing biomass pellet fuel using bamboo materials as described in claim 1, wherein, in the crushing step, the predetermined particle size is 30 mm. The method for producing biomass pellet fuel using bamboo materials as described in claim 2, wherein, in the pulverization step, the produced particle size is 6 mm. The method for producing biomass pellet fuel using bamboo materials as described in claim 1 further includes a screening step after the cooling step, wherein the screening step removes dust and debris that cannot be formed in the granulation step and reintroduces the remaining powder to be formed that has been screened into the water-washing and pulverizing equipment. The method for producing biomass pellet fuel using bamboo materials as described in claim 4, wherein the pelletizing equipment is a ring die pelletizer. The method for producing biomass pellet fuel using bamboo materials as described in any one of claims 1 to 5, wherein, in the crushing step, the bamboo waste is selected from bamboo processing waste, bamboo residual materials, or any combination thereof. The method for producing biomass pellet fuel using bamboo materials as described in any one of claims 1 to 5, wherein, in the pelletizing step, each biomass pellet fuel is cylindrical. The method for producing biomass fuel pellets from bamboo materials as described in claim 7, wherein each biomass fuel pellet has an outer diameter of 6 to 25 mm and a length of 3 to 50 mm. The method for producing biomass pellet fuel from bamboo materials as described in any one of claims 1 to 5 further includes a recycling step, wherein the recycling step uses the biomass pellet fuel as fuel for a gasifier and introduces a high-temperature gas flow after gasification into the drying equipment. The method for producing biomass pellet fuel using bamboo materials as described in claim 9, wherein, in the recycling step, 6.0-8.0% by weight of the produced biomass pellet fuel is used as fuel for the gasifier.