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JP-7856274-B1 - Quality evaluation method for fuel pellets made of EFB

JP7856274B1JP 7856274 B1JP7856274 B1JP 7856274B1JP-7856274-B1

Abstract

[Problem] To provide a quality evaluation method that can estimate, i.e., evaluate, the chlorine concentration of fuel pellets within a predetermined concentration range at a site where fuel pellets are manufactured from EFB (Energy Fiber Blast). [Solution] This is a quality evaluation method for evaluating the chlorine concentration in fuel pellets manufactured using EFB as a raw material. The quality evaluation method comprises a potassium concentration estimation step for estimating the potassium concentration in the fuel pellets, and a chlorine concentration evaluation step for evaluating the chlorine concentration. Based on the estimated potassium concentration, the chlorine concentration evaluation step evaluates that when the potassium concentration is 4,000 ppm or less, the chlorine concentration is less than or equal to the potassium concentration multiplied by 0.086. [Selection Diagram] Figure 3

Inventors

  • 洲脇 康史
  • 鈴木 光匡
  • 西田 泰規
  • 平野 高宏

Assignees

  • テス・エンジニアリング株式会社

Dates

Publication Date
20260511
Application Date
20260220

Claims (8)

  1. A quality evaluation method for evaluating the chlorine concentration in fuel pellets manufactured using EFB as a raw material, The quality evaluation method comprises a potassium concentration estimation step for estimating the potassium concentration in the fuel pellet and a chlorine concentration evaluation step for evaluating the chlorine concentration. The chlorine concentration evaluation step is performed based on the estimated potassium concentration, (1) When the potassium concentration is 4,000 ppm or less, the chlorine concentration is less than or equal to the value obtained by multiplying the potassium concentration by 0.086. A method for evaluating the quality of fuel pellets consisting of EFB, which are evaluated as follows.
  2. The chlorine concentration evaluation step further includes: (2) When the potassium concentration is 3,000 ppm or less, the chlorine concentration is less than or equal to the value obtained by multiplying the potassium concentration by 0.066. A method for evaluating the quality of fuel pellets made of EFB according to claim 1, which is evaluated as follows.
  3. The chlorine concentration evaluation step further includes: (3) When the potassium concentration is 2,000 ppm or less, the chlorine concentration is less than or equal to the potassium concentration multiplied by 0.050. A method for evaluating the quality of fuel pellets comprising EFB according to claim 1 or 2, which is evaluated as follows.
  4. The potassium concentration estimation step involves setting a predetermined amount of the fuel pellets to be used as test pellets, placing the test pellets in a predetermined amount of hot water to loosen them, immersing them for a predetermined time or longer, measuring the potassium concentration in the hot water (hot water potassium concentration), and estimating the contained potassium concentration from the hot water potassium concentration, as described in claim 1 or 2, for the quality evaluation method of fuel pellets made of EFB.
  5. The method for evaluating the quality of fuel pellets according to claim 4, wherein the hot water is 10 times the mass of the test pellet and is heated to 70°C or higher, and the specified time is 10 minutes.
  6. The method for evaluating the quality of fuel pellets according to claim 4, wherein the estimation of the potassium content is performed by multiplying the potassium concentration in the hot water by a predetermined elution coefficient to calculate the potassium content initially present in the test pellet.
  7. A method for evaluating the quality of fuel pellets according to claim 1, wherein the manufacturing process for producing the fuel pellets from EFB includes at least a washing step of crushing the EFB and immersing it in washing water, the fuel pellets are manufactured so that the potassium concentration is 3,400 ppm or less, and the chlorine concentration of the fuel pellets is evaluated to be 300 ppm or less.
  8. A method for evaluating the quality of fuel pellets according to claim 2, wherein the manufacturing process for producing the fuel pellets from EFB includes at least a washing step of crushing the EFB and immersing it in washing water, the fuel pellets are manufactured so that the potassium concentration of the fuel pellets is 3,000 ppm or less, and the chlorine concentration of the fuel pellets is evaluated to be 200 ppm or less.

Description

This invention relates to a quality evaluation method for fuel pellets manufactured using palm fruit bunches, or EFB (Empty Fruit Bunch), as a raw material. Palm fruit is contained in clusters of palm fruit, and palm oil is obtained by pressing the fruit separated from these clusters. The remaining clusters after the fruit has been removed, known as EFBs (empty palm fruit clusters), are generated in large quantities at palm oil plants and were traditionally discarded. However, in recent years, they have begun to be used to produce fuel pellets. Incidentally, regarding wood pellet fuel, the International Organization for Standardization (ISO), the European Committee for Standardization (ESCO), and others have established quality standards. This is to ensure a certain level of quality so that it can be used safely and appropriately when used in boilers, etc. For example, according to the ISO 17225-1 (2021) standard, the highest quality category A1 specifies requirements such as an ash melting behavior, i.e., an ash softening point temperature (DT) of 1,200°C or higher, and a chlorine (Cl) concentration of 200 ppm or less. Fuel pellets made from EFB (Energy-Free Bone) should also be supplied in accordance with these standards to ensure safe use in boilers. EFB contains a relatively high amount of potassium, a low-melting-point metal. While these standards do not specify potassium concentration, high potassium concentrations can lead to clinker formation in the fluidized bed during combustion in boilers, causing combustion ash to solidify and adhere to the furnace and heating pipes, resulting in fouling and slugging. This is because potassium lowers the ash softening point (DT). Therefore, when manufacturing fuel pellets from EFB, as described in Patent Document 1, for example, the EFB is crushed and immersed in washing water to reduce the potassium concentration before being molded into pellets. The ash softening point (DT) of fuel pellets made of EFB (Energy-Fuel-Based Bomb) is measured by providing a sample of the fuel pellets to a specialized analytical laboratory. However, this process takes a long time, affecting the efficiency of fuel pellet manufacturing. The ash softening point (DT) is correlated with potassium concentration. Therefore, at the fuel pellet manufacturing site, a relatively simple testing device is used to measure the potassium concentration of the fuel pellets, and this is used to estimate whether the ash softening point (DT) meets the standard. This is then confirmed by the test results received later from the analytical laboratory. Even if the ash softening point (DT) does not meet the standard for category A1, clinker formation can be suppressed, for example, by co-firing the fuel pellets with other fuels at a predetermined co-firing ratio. However, even in this case, improvement of the ash softening point (DT) is necessary, and controlling the potassium concentration within an appropriate range is required. Japanese Patent Publication No. 2025-24612 This is a flowchart showing the manufacturing process for producing fuel pellets from EFB (Energy Fiber Blast).This graph shows the relationship between potassium concentration and chlorine concentration in fuel pellets made of EFB (Energy-Fuel-Based Batter).This graph shows the relationship between potassium concentration and chlorine concentration in fuel pellets made of EFB (Energy-Fuel-Based Batter).This flowchart shows the procedure for evaluating the chlorine concentration in fuel pellets made of EFB (Energy Fiber Bomb). <This embodiment> Embodiments of the present invention will be described below. The fuel pellet quality evaluation method according to this embodiment is a method for evaluating the chlorine concentration of fuel pellets made of EFB. In fuel pellets made of EFB, the chlorine concentration is often reduced by a washing process, which will be explained later, but as a result the chlorine concentration becomes quite low, making it difficult to directly measure the concentration. Therefore, in the fuel pellet quality evaluation method according to this embodiment, the chlorine concentration is evaluated based on the concentration of another substance that is relatively easy to measure. Specifically, the potassium concentration contained in the fuel pellet is used, and the chlorine concentration is evaluated based on this. <Manufacturing of fuel pellets made from EFB> First, the manufacturing method for fuel pellets made of EFB, which is the target of the fuel pellet quality evaluation method according to this embodiment, will be explained. EFB is first pressed in a pressing step SS1 as shown in Figure 1. EFB is in a state from which the palm fruit has been removed, and it is heated and pressed. This separates the water containing oil. EFB oil is produced from the oil. A water addition step SS2 is carried out on the pressed EFB as needed. That is, water is added. Alternatively, the crushing step SS3 may be performed afte