Method for treating waste plastics

Abstract

A method for processing waste plastic, characterized in that, after dry distillation of coal using a coke oven, when waste plastic is loaded into a coke oven top space portion above the loaded coal in a carbonization chamber to produce coke, a loading test is performed in advance on a physical size model of the carbonization chamber 2 to determine the bulk density p of the waste plastic, in kg / mm 3 , and the angle of repose θ of the pile formed by the loaded waste plastic 12, in °, based on the height h space of the coke oven top space portion, the height y of the waste plastic 12 loaded into the coke oven top space portion 5 is determined, the waste plastic loading amount x, in kg, for each loading port is estimated based on the following (1) and (2) formulas, and determined, y = k × x 0.5 (1) k = (tan θ / (p × d)) 0.5 (2) where d is the oven width of the carbonization chamber, in mm.

Description

Technical Field

[0001] This invention relates to a method for treating waste plastics by loading coal (for coke manufacturing) and waste plastics into the carbonization chamber of a coking oven for dry distillation. Background Technology

[0002] Regarding the disposal of waste plastics, which are discharged in large quantities as industrial waste and general plastic waste, the majority has historically been landfilled or partially incinerated. However, waste plastics are not decomposed by microorganisms and bacteria in the soil during landfilling. Incineration generates a large amount of heat, negatively impacting incinerators, and the treatment of chlorine in the exhaust gases becomes problematic, especially with waste plastics containing chlorine. Anticipating future landfill shortages and increasing environmental concerns, there is a desire to promote the recycling of waste plastics. Recycling methods, in addition to reusing the plastics themselves, include utilizing the heat from combustion and using the gases and oils obtained from thermal decomposition as fuels and chemical feedstocks.

[0003] For example, Patent Document 1 discloses a method for reusing waste plastics by mixing plastic granules formed at 100-160°C with coal and then dry distilling the mixture in a coking oven. On the other hand, Patent Document 2 describes that if a large amount of plastic is mixed, the strength of the resulting coke will decrease. In order to keep the decrease in coke strength to around a few percent, the mass ratio of plastic to coal needs to be less than 1%. Depending on the target coke strength grade, the amount that can be reused is limited.

[0004] As a method for adding waste plastics to a coke oven for processing, one known method involves loading the waste plastics into a space above the coal loaded into the carbonization chamber. According to Patent Document 3, in this method, most of the waste plastics can be thermally decomposed in the high-temperature coke oven, resulting in high-calorie thermal decomposition gases containing hydrogen, methane, ethane, propane, etc. These thermal decomposition gases are contained in the coke oven gases generated within the coke oven carbonization chamber through the thermal decomposition of coal and are thus recovered and reused as an energy source.

[0005] For example, Patent Document 4 discloses a method for producing coke by loading waste plastic into the upper space of the carbonization chamber after dry distillation of coal in a coke oven. The preferred loading time is during the coke maturation period (approximately 2 hours), known as the normal settling time, from the end of dry distillation to the removal of the coke. This is because during this time, the amount of gas typically generated in the coke oven is relatively small, and the heat dissipation from the coke oven is relatively large, which can be utilized as heat of gas decomposition.

[0006] Patent Document 5 relates to a method for treating waste plastics, characterized by preparing coke-making coal or coke-making coal containing 0.1 to 1.0 wt% waste plastics, loading it into a coking oven, and then further loading waste plastics into the overhead space above the coal. During dry distillation, the waste plastics are thermally decomposed and recovered as tar, light oil, and gas. This method discloses a method for loading waste plastics into the overhead space above the coal after loading, and a method for supplying waste plastics from the coal loading point until the end of dry distillation via a supply device leading to the coking oven's overhead space. Through these methods, in the example of this document where waste plastics are loaded into the overhead space, the same amount of waste plastics can be treated as when approximately 5 wt% waste plastics are added. On the other hand, regarding Patent Document 2, the method described in Patent Document 5 involves opening the raw material loading cover and loading waste plastic during the dry distillation of coal in the carbonization chamber of a coking oven. Therefore, it is necessary to ensure that the amount of gas generated in the carbonization chamber does not exceed the gas recovery capacity of the riser pipe.

[0007] Patent document 3 discloses a method for producing coke in which coke raw material is first loaded into the carbonization chamber of a coking oven, and then waste plastic is loaded into the space at the top of the oven. This method suppresses dust during ejection and reduces ejection resistance. In this document, the loading of waste plastic is preferably carried out after the fire has died down (when dry distillation is complete). This is because, generally, if it is done after the fire has died down, the gas production caused by the thermal decomposition of the coke raw material is reduced, and the heat dissipation from the coking oven body is increased. However, it also has the advantage of being able to use this heat for the thermal decomposition of waste plastic.

[0008] Patent document 6 describes a coal leveler that evenly levels the unevenness of the top surface of the coal charged into the coking chamber of a coke oven. The leveler consists of multiple bottomless boxes separated by partitions. Return coal is supplied into the boxes of the leveler. By advancing the leveler into the coking chamber, the return coal falls according to the unevenness of the top surface of the coal, thus leveling the top surface of the coal. When the leveler retracts, excess coal and return coal move into the boxes of the leveler and are recovered, to be reused as return coal in the next charging cycle.

[0009] Patent documents 7 and 8 disclose methods for precisely controlling the coal charging height in the coking chamber of a coke oven, aiming to keep the coal charging height as constant as possible throughout the coking chamber. Therefore, patent documents 7 and 8 describe a method that pre-estimates the relationship between the volume and mass of the coal and the coal pile height, and sets the coal charging amount based on the target coal pile height. Therefore, patent documents 7 and 8 do not describe a method for adding waste plastics to the coke oven for processing. Furthermore, both patent documents 7 and 8 consider the shape of the upper part of the coal before dry distillation as a horizontal plane.

[0010] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2001-49261 Patent Document 2: Japanese Patent Application Publication No. 2019-135278 Patent Document 3: Japanese Patent Application Publication No. 2002-47494 Patent Document 4: Japanese Patent Application Publication No. 4-41588 Patent Document 5: Japanese Patent Application Publication No. 8-157834 Patent Document 6: Japanese Patent Application Publication No. 2002-371285 Patent Document 7: Japanese Patent Application Publication No. 2014-088528 Patent Document 8: Japanese Patent Application Publication No. 2-235988 Summary of the Invention

[0011] The problem that the invention aims to solve This invention relates to a method for treating waste plastics by loading coal (for coke production) and waste plastics into the carbonization chamber of a coking oven for dry distillation. The method focuses on the method of loading waste plastics into the top space of the furnace above the coke layer formed by dry distilling coal in the coking oven.

[0012] When loading waste plastics into the furnace top space after coal dry distillation, it is necessary to maximize the amount of waste plastics loaded to improve waste plastic processing productivity. On the other hand, if too much waste plastic is loaded into the furnace top space, the gap between the top of the loaded waste plastics and the top of the carbonization chamber becomes insufficient, resulting in insufficient heating and blockage in the upper layer. When loading waste plastics, it is necessary to load the maximum amount of waste plastics based on accurately determining the height of the coke layer after dry distillation and accurately predicting the upper limit of the amount of waste plastics that can be loaded.

[0013] The first objective of this invention is to provide a method for processing waste plastics, which maximizes the amount of waste plastics that can be loaded into the top space of the furnace above the coal in the carbonization chamber after the dry distillation of coal in a coking oven to produce coke. The second objective is to accurately estimate the volume of the top space after dry distillation.

[0014] Methods for solving problems In other words, the key points of this invention are as follows.

[0015] [1] A method for treating waste plastics, wherein coal for coke manufacturing (hereinafter referred to as "coal to be loaded") and waste plastics are loaded into the carbonization chamber of a coking oven for dry distillation. The method for treating waste plastics is characterized in that, Based on the height of the space from the top of the coke-forming layer in the carbonization chamber to the top of the carbonization chamber (hereinafter referred to as the "furnace top space") after the coal has undergone dry distillation (hereinafter referred to as the "furnace top space height"), determine the amount of waste plastic to be loaded. Based on the height of the furnace top space, the height y of the waste plastic pile (bulge) loaded into the furnace top space from each loading inlet is determined. Based on the following equations (1) and (2) which express the relationship between the amount of waste plastic loaded at each loading inlet x (kg) and the height of the waste plastic y (mm), the amount of waste plastic loaded at each loading inlet x (kg) is estimated, and the amount of waste plastic to be loaded is determined. y=k×x 0.5 (1) k = (tanθ / (ρ×d)) 0.5 (2) Wherein, ρ: bulk density of waste plastic (kg / mm²) 3 ), d: furnace width of the carbonization chamber (mm), θ: angle of repose (°) of the pile of waste plastics loaded from each inlet. The bulk density ρ (kg / mm²) 3 The angle of repose θ (°) was determined in advance by using a loading test of a full-size model of the carbonization chamber, or by filling the sample into a container with a known volume as shown in JIS K2151 and weighing the mass. In addition, the loading test of the full-size model was used to determine the angle of repose in advance.

[0016] [2] The method for treating waste plastics according to [1] is characterized in that, The height of the furnace top space is determined based on the estimated height of the upper part of the coke layer after dry distillation. Regarding the estimation of the height of the upper end of the coke layer after carbonization, in the past, based on the actual results of multiple processing, the height of the upper end of the coke layer after carbonization was measured, and an estimated formula relating the amount of coal to be loaded to the height of the upper end of the coke layer after carbonization was derived in advance for determination.

[0017] [3] The method for treating waste plastics according to [1] is characterized in that, The height of the furnace top space is determined based on the estimated height of the upper part of the coke layer after dry distillation. Regarding the estimation of the height of the upper end of the coke layer after carbonization, in the past, based on the actual results of multiple processing, the height of the upper end of the coke layer after carbonization was measured, and an estimated formula relating the amount of coal to be loaded, the moisture content of the coal to be loaded, and the height of the upper end of the coke layer after carbonization was derived in advance.

[0018] [4] The method for treating waste plastics according to [1] is characterized in that, The height of the upper part of the coke layer after dry distillation is determined by measuring the level gauge, and the height of the furnace top space is determined based on the determined upper part of the coke layer after dry distillation.

[0019] In this invention, after the coal is dry-distilled in a coking oven, waste plastic is loaded into the top space above the coal in the carbonization chamber to produce coke. Beforehand, a loading test is conducted on a full-size model of the carbonization chamber to determine the bulk density ρ of the waste plastic and the angle of repose θ of the pile formed by the loaded waste plastic. The amount of waste plastic to be loaded is determined based on a prescribed formula, which is used to estimate the relationship between the amount of waste plastic loaded x at each loading inlet and the height y of the waste plastic. This allows for the loading of waste plastic to be maximized. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view showing an example of waste plastic being loaded into the space above the carbonization chamber.

[0021] Figure 2 This is a diagram showing the cross-section of the carbonization chamber before the waste plastic is loaded after the dry distillation is complete.

[0022] Figure 3 It is a cross-sectional view showing the position of the upper end of the coke layer after dry distillation, as measured by a level gauge. Detailed Implementation

[0023] Figure 1 This indicates that waste plastic 12 has been loaded into the furnace top space 5. Figure 2This shows the cross-section of the carbonization chamber 2 of the coke oven 1 after dry distillation. The upper position 14 of the coal bed after loading (the upper end of the coal before dry distillation) is indicated by a double-dotted line. A coke layer 11 (the coal after dry distillation) is formed in the carbonization chamber 2, and the generated gas is discharged through the riser pipe 3. A loading inlet 4 is located at the top of the carbonization chamber 2. During dry distillation, burn-off occurs, and the height decreases from the upper position 14 of the coal bed before dry distillation to the upper position 13 of the coke layer after dry distillation. The upper end of the coke layer 11 is the upper position 13 of the coke layer after dry distillation, and the space above the coke layer 11 is the furnace top space 5. Figure 3 This indicates that after the dry distillation is completed, the level gauge 6 is used to measure the condition of the upper position 13 of the coke layer after dry distillation through the loading inlet 4.

[0024] (Implementation Method 1) First, a test was conducted to load a full-size model of the waste plastic into the carbonization chamber. First, the bulk density ρ (kg / mm²) of the waste plastic was evaluated. 3 Bulk density ρ (kg / mm³) 3 The volume of the stockpile of waste plastics is calculated by examining a full-scale model test, and then back-calculated from the mass of the waste plastics added. Furthermore, the bulk density ρ of the waste plastics can be evaluated using a method as shown in JIS K2151, where a sample is filled into a container of known volume and its mass is weighed. Additionally, the angle of repose θ (°) of the inclined plane of the stockpile of waste plastics loaded into the carbonization chamber is measured in the longitudinal direction of the furnace through a full-scale model loading test. The angle of repose θ can be measured directly using a protractor or by processing data from an image obtained from photographing the shape of the stockpile of waste plastics. Here, if we observe the shape of the waste plastic pile in the space at the top of the carbonization chamber, in a full-size model experimental setup with a furnace width of d (mm), when waste plastic is loaded from a simulated loading inlet and the amount of waste plastic loaded is x (kg), when viewed from the furnace width direction, the waste plastic pile forms an isosceles triangle with a height of y (mm) and an angle of repose of θ (°) on its inclined plane in the furnace length direction. If the area of ​​this triangle is set as A (mm²),... 2 The relationship is as follows:

[0025] A=y 2 / tanθ (3) ρ×d×A=x (4) Transform the relation, k = (tanθ / (ρ×d)) 0.5 (2) The following relation is then obtained.

[0026] y=k×x 0.5(1) This formula represents the relationship between the amount of waste plastic loaded x (kg) and the height y (mm) of the waste plastic pile.

[0027] As a full-scale model experimental apparatus, the width d of the carbonization chamber, the distance from the inlet to position 13 at the top of the coke layer after dry distillation, and the loading speed of the waste plastic were made identical to those of a real coking oven, and waste plastic loading tests were conducted. Two types of waste plastic were used: "low-density" and "high-density". During loading into the coking oven, to improve operability in the conveying process and increase the loading density of the plastic, a volume reduction molding machine was used to compress and shape the waste plastic. Depending on the molding conditions, it was classified into hard granular "high-density" and softer "low-density". As a result, the bulk density ρ of the waste plastic and the angle of repose θ of the waste plastic pile were measured as shown in Table 1.

[0028] [Table 1] That is, if the height y of the waste plastic pile is determined, the amount of waste plastic x required to achieve the height of the pile for each loading inlet can be determined based on equations (1) and (2). In addition, when the carbonization chamber has multiple loading inlets, after calculating the amount of waste plastic x for each loading inlet using the above method, the amount of waste plastic x from each loading inlet is summed, thereby determining the total amount of waste plastic in the carbonization chamber.

[0029] Next, as Figure 1 As shown, the height y of the waste plastic pile is determined by the height h of the space at the top of the furnace. space Confirmed. Regarding the height y of the waste plastic pile and the height h of the space above the furnace. space The relationship can be set to h. space The range of >y is acceptable. From an operational efficiency perspective, maximizing the height y of the waste plastic pile is preferable; the closer y is to h, the better. space The better.

[0030] (Implementation Method 2) The coal to be charged into the coking oven contains moisture, and the coal charging amount t is expressed as the amount of coal charged with moisture (wet-t / ch). Here, wet-t is the mass of the coal charged in its moisture-containing state. Additionally, ch is the charging amount per carbonization chamber. For the height h of the upper end of the coke bed after dry distillation... coke (mm), which can be measured by lowering a measuring rod from the top of the furnace. By measuring the material level under multiple conditions with different charging amounts, the relationship between the coal charging amount t (wet-t / ch) and the height h of the upper end of the coke bed after dry distillation is derived. cokeThe relationship (mm) is used as a preliminary formula. For example, the above measurements were performed in a specific carbonization chamber, and the following results were obtained.

[0031] h coke =141.17×t+1453.3 (5) This is the result of varying the coal loading amount (t, wet-t / ch) within the range of 12 to 15 (wet-t / ch). The moisture content of the coal used is approximately 2%.

[0032] like Figure 1 As shown, since the height h of the carbonization chamber is known... oven (mm), therefore regarding the height h of the furnace top space. space (mm), the following results can be calculated.

[0033] h space =h oven -h coke (6) That is, in the waste plastic treatment method of the present invention, based on the height h of the upper end of the coke layer after dry distillation... coke The height h of the furnace top space is determined by estimation. space Regarding the height h of the upper end of the coke layer after dry distillation coke The estimation can be used to determine the height h of the upper end of the coke layer after dry distillation in many past processing results. coke The amount of coal to be loaded (t) and the height (h) of the top of the coke bed after dry distillation are pre-derived. coke The relationship is presumed and thus predetermined.

[0034] (Implementation Method 3) If the dry distillation of coal is carried out in the carbonization chamber of a coke oven, then the height h of the coal immediately after loading will be... caol In terms of the height h at the top of the coke layer after dry distillation coke Reduce. Set the reduction amount to h. drop (mm). This phenomenon is called "burn-off". The burn-off rate r (%) is calculated by the following equations (7) and (8).

[0035] h drop =h caol -h coke (7) r=h drop / h caol ×100 (8) The height h of the coal immediately after it is loaded is measured by lowering a measuring rod from the top of the furnace. caol and the height h of the upper end of the coke layer after dry distillation cokeBy measuring the coal level under various conditions with different coal moisture contents w (%), the variation in burn-off under different moisture levels was clarified. The burn-off rate (r) varies depending on the coke moisture content. The relationship between the burn-off rate r (%) and the coal moisture content w (%) was measured as follows.

[0036] r = 0.33 × w + 0.66 (9) As long as the moisture content w (%) of the coal to be loaded and the height h of the coal immediately after loading are determined... caol Then, for the height h at the top of the coke layer after dry distillation coke It can be calculated from the above equation (9) and the following equation (10).

[0037] h coke =h caol ×(1-r / 100) (10) Regarding the height h of the coal immediately after loading caol (mm), which can be measured by lowering a measuring rod from the top of the furnace immediately after loading. By measuring the material level under multiple conditions with different loading amounts, the relationship between the coal loading amount t (wet-t / ch) and the coal height h immediately after loading can be derived in advance. caol The relationship (mm) is used as a first-order presumption.

[0038] That is, in the waste plastic treatment method of the present invention, based on the height h of the upper end of the coke layer after dry distillation... coke The height h of the furnace top space is determined by estimation. space Regarding the height h of the upper end of the coke layer after dry distillation. coke Based on the assumptions made in previous processing of actual results, the height h of the coal immediately after loading was measured. caol The height h of the upper end of the coke layer after dry distillation coke The moisture content w of the coal to be loaded is pre-exported, and the height h of the coal immediately after loading is determined. caol The height h of the upper end of the coke layer after dry distillation coke The inference of the influence caused by the relationship. The height h of the coal immediately after loading can be used. caol Based on the measured value of the moisture content w of the coal being charged, the height h of the upper end of the coke bed after dry distillation is estimated using the above estimation formula. coke And confirm it.

[0039] (A variation of Implementation Method 3) As another variation of embodiment 3, the following method can also be used. That is, it is assumed that the height h of the upper end of the coke bed after dry distillation is represented by two variables: the amount of coal charged t (wet-t / ch) and the moisture content of the charged coal w (%). cokeThe formula (mm) establishes a linear equation in two variables. Based on this, for various coal loading amounts and moisture content, the height h of the upper end of the coke bed after dry distillation is measured. coke Furthermore, methods such as multiple regression analysis can be used to determine the coefficients of the linear equation in two variables. Based on the above observations, the linear equation in two variables is determined in advance. After identifying the moisture content w of the coal to be loaded, the coal loading amount t (wet-t / ch) is determined and substituted into the pre-determined linear equation in two variables. From this, the height h of the upper end of the coke layer after dry distillation can be calculated. coke .

[0040] That is, in the waste plastic treatment method of the present invention, based on the height h of the upper end of the coke layer after dry distillation... coke The height h of the furnace top space is determined by estimation. space Regarding the height h of the upper end of the coke layer after dry distillation coke The estimation can be used to determine the height h of the upper end of the coke layer after dry distillation in many past processing results. coke The amount of coal to be loaded (t), the moisture content (w) of the coal to be loaded, and the height (h) of the top of the coke bed after dry distillation. coke The presumed formula of the relationship is determined in advance as a linear equation in two variables.

[0041] Next, the amount of coal to be loaded (t), the moisture content (w) of the coal to be loaded, and other processing conditions are considered for the height (h) of the upper part of the coke bed after dry distillation. coke The influence of these parameters was investigated. Similar to the experiments described above, the position 13 of the upper end of the coke layer after dry distillation was measured for multiple carbonization chambers 2, and the relationship between the amount of coal to be loaded and various processing conditions was investigated. The results show that if the particle size of the loaded coal, the volatile matter content of the coal, the degree of carbonization of the coal, the composition of the coal (C / N / O, etc.), the dry distillation conditions (furnace temperature, carbonization time), and the coal loading speed change, the position 13 of the upper end of the coke layer after dry distillation will also change, even with the same amount of coal loaded. The influence of these parameters on the position 13 of the upper end of the coke layer after dry distillation can be expressed as a multivariate linear function. These parameters can also be considered to improve the estimation accuracy.

[0042] Furthermore, the measured position 13 of the top of the coke layer after dry distillation has a linear correlation with the amount of coal charged, and even with the same amount of coal charged, the position 13 of the top of the coke layer after dry distillation varies for each carbonization chamber 2. Therefore, in such cases, it is preferable to set an estimate for the position 13 of the top of the coke layer after dry distillation for each carbonization chamber 2. For each carbonization chamber 2, based on past processing results, the position 13 of the top of the coke layer after dry distillation is measured, and an estimate of the relationship between the amount of coal to be charged and the position 13 of the top of the coke layer after dry distillation is derived as a linear equation. By substituting the amount of coal charged in this processing into the above estimate, the position 13 of the top of the coke layer after dry distillation in the carbonization chamber 2 of the processing being applied can be estimated. When deriving the estimate based on past processing results, by including processing with as many different amounts of coal charged as possible, a highly accurate estimate can be obtained. These parameters can also be considered to improve the estimation accuracy.

[0043] Furthermore, in addition to investigating the behavior of each carbonization chamber, the relationship between the measured position 13 of the upper end of the coke layer after dry distillation at each loading inlet 4 of each carbonization chamber 2 and the processing parameters was investigated. As a result, even for the same carbonization chamber 2, the estimation formula for the upper end position 13 of the coke layer after dry distillation at each loading inlet 4 sometimes differs. Therefore, in such cases, in estimating the upper end position 13 of the coke layer after dry distillation, it is more preferable to derive an estimation formula for each loading inlet 4, in addition to each carbonization chamber 2, based on past processing results, and to estimate the upper end position 13 of the coke layer after dry distillation based on the measured value of each loading inlet 4. Here, the furnace top deck thickness, conical section height, non-conical section height, coal leveler height, and loading inlet size of the carbonization chamber can be common to all loading inlets. Then, corresponding to the estimated value of the upper position 13 of the coke layer after dry distillation for each loading inlet 4, the amount of waste plastic 12 to be loaded into the furnace top space 5 above the coke layer is determined for each loading inlet 4. This allows for a more accurate estimation of the volume of the furnace top space 5, and enables the amount of waste plastic 12 to be loaded into the furnace top space 5 to be increased to its maximum. These parameters can also be considered to improve the estimation accuracy.

[0044] Regarding the determination of the position 13 at the top of the coke layer after dry distillation, it can be measured manually during the preparation of the estimation model, similar to the experiment described above. However, it is more preferable to use a level gauge 6 to directly measure each loading inlet 4. The level gauge 6 can be either differential pressure type or microwave type. The differential pressure level gauge measures the distance by measuring the pressure change at the nozzle when a nozzle descends in a telescoping motion while a small amount of gas is ejected from the top and contacts the sample. The microwave level gauge measures the distance by measuring the round-trip propagation time from the microwave pulse transmitted from the sensor's antenna to the reflection of the sample surface and its reception by the antenna again as a reflected pulse. By placing the level gauge 6 above the loading inlet 4 of the carbonization chamber 2, the position 13 at the top of the coke layer after dry distillation within the carbonization chamber can be measured when the loading inlet 4 is open.

[0045] Regarding the loading of waste plastics into the carbonization chamber, besides loading waste plastics 12 into the furnace top space 5 above the coke layer after dry distillation, waste plastics can also be mixed into the coal before loading. The mixing of waste plastics into the coal is a major cause of variations in the height of the upper coke layer after dry distillation. Therefore, in multiple practical studies, the mixing rate of waste plastics into the coal and the properties of the waste plastics before loading were investigated to determine their impact on the estimated height of the upper coke layer after dry distillation. The properties of the waste plastics can be parameterized using particle size, apparent specific gravity, bulk density, and angle of repose. The results clarified the impact of the mixing rate of waste plastics and the aforementioned waste plastic property parameters on the height of the upper coke layer after dry distillation; any one of these parameters can be incorporated into the estimation formula as a linear expression. These parameters can also be considered to improve the estimation accuracy.

[0046] In this invention, when estimating the height of the upper end of the coke layer after carbonization based on a presumption, the presumption can be stored in a computer system, and the parameters to be input into the presumption can be input into the computer system. The computer system then calculates the estimated value of the upper end height of the coke layer after carbonization. Preferably, the parameters to be input into the presumption are automatically input into the computer system online. Furthermore, it is preferable that after calculating the estimated value of the upper end height of the coke layer after carbonization using the computer system, the amount of waste plastic to be loaded into the furnace top space is determined based on the calculated estimated value. The automatic control of the computer system can be performed for each carbonization chamber, and further for each loading inlet. More preferably, by inputting the measured value of the upper end position 13 of the coke layer after carbonization into the computer system, the presumption using the measured value can be automatically corrected online.

[0047] Explanation of reference numerals in the attached figures 1. Coke oven; 2. Carbonization chamber; 3. Ascension pipe; 4. Charging inlet; 5. Oven top space; 6. Material level gauge; 11. Coke layer; 12. Waste plastic; 13. Upper position of coke layer after dry distillation; 14. Upper position of coal layer after charging.

Claims

1. A method for treating waste plastics, comprising loading coal (used in coke production) and waste plastics into the carbonization chamber of a coking oven for dry distillation. The method for treating waste plastics is characterized in that, This method determines the amount of waste plastic to be loaded based on the height of the furnace top space. The height of the furnace top space is the distance from the top of the coke layer in the carbonization chamber to the top of the carbonization chamber after the coal has undergone dry distillation. Based on the height of the furnace top space, the height y of the waste plastic pile loaded into the furnace top space from each loading inlet is determined. Based on the following equations (1) and (2) representing the relationship between the amount of waste plastic loaded at each loading inlet x and the height y of the waste plastic, the amount of waste plastic loaded at each loading inlet x is estimated, and the amount of waste plastic to be loaded is determined, wherein, The unit for x is kg, and the unit for y is mm. y=k×x 0.5 (1) k=(tanθ / (ρ×d)) 0.5 (2) Where ρ: bulk density of waste plastic, in kg / mm³ 3 ; d: Furnace width of the carbonization chamber, in mm; θ: Angle of repose of the piles of waste plastics formed by the various loading inlets, in °. The bulk density, ρ, is measured in kg / mm². 3 The angle of repose θ, in °, was determined in advance by using a loading test of a full-size model of the carbonization chamber, or by filling the sample in a container with a known volume as shown in JIS K2151 and weighing the mass.

2. The method for treating waste plastics as described in claim 1, characterized in that, The height of the furnace top space is determined based on the estimated height of the upper part of the coke layer after dry distillation. Regarding the estimation of the height of the upper end of the coke layer after carbonization, in the past, based on the actual results of multiple processing, the height of the upper end of the coke layer after carbonization was measured, and an estimated formula relating the amount of coal to be loaded to the height of the upper end of the coke layer after carbonization was derived in advance for determination.

3. The method for treating waste plastics as described in claim 1, characterized in that, The height of the furnace top space is determined based on the estimated height of the upper part of the coke layer after dry distillation. Regarding the estimation of the height of the upper end of the coke layer after carbonization, based on past practical results, by measuring the height of the coal immediately after loading and the height of the upper end of the coke layer after carbonization, an estimation formula was derived in advance to estimate the influence of the moisture content of the coal to be loaded on the relationship between the height of the coal immediately after loading and the height of the upper end of the coke layer after carbonization. Using the measured values ​​of the height of the coal immediately after loading and the moisture content of the loaded coal, the height of the upper end of the coke layer after dry distillation is estimated and determined by the estimation formula.

4. The method for treating waste plastics according to claim 1, characterized in that, The height of the upper part of the coke layer after dry distillation is determined by measuring the level gauge, and the height of the furnace top space is determined based on the determined upper part of the coke layer after dry distillation.

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