Method for estimating the heat of chemical reaction of polymer compounds and method for thermal decomposition treatment of waste plastics

Abstract

This invention provides a method for estimating the heat of chemical reaction of polymer compounds containing repeating units, such as waste plastics, and a method for thermal decomposition treatment of waste plastics. [Solution] A method for estimating the heat of chemical reaction of a polymer compound, comprising: representing the chemical reaction of a polymer compound containing repeating units containing carbon and hydrogen in units of molecular constituents smaller than the repeating units; stoichiometrically estimating the standard enthalpy of formation of the molecular constituent units using known literature data on the heat of complete combustion; and estimating the amount of heat absorbed or released during the chemical reaction of the polymer compound based on the estimated standard enthalpy of formation of the molecular constituent units. Using the estimation method, the heat of reaction in the thermal decomposition treatment of waste plastics is estimated, the specifications of the heating device are determined based on the estimated value, and the thermal decomposition treatment of waste plastics is performed.

Description

Technical Field

[0001] The present disclosure relates to a method for estimating the heat of chemical reaction of a polymer compound and a method for thermally decomposing waste plastics.

Background Art

[0002] As a method for treating used waste plastics, a technique for thermally decomposing waste plastics (used plastics) and recycling them as resources such as pyrolysis oil is known (see, for example, Patent Document 1).

[0003] Patent Document 2 discloses a pyrolysis treatment apparatus for thermally decomposing waste plastics, which includes a pyrolysis tank for accommodating waste plastics, heating means provided in the pyrolysis tank for heating the waste plastics in the pyrolysis tank, and control means for controlling the heating amount of the heating means to adjust the temperature in the pyrolysis tank.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] When waste plastics are thermally decomposed and gasified or liquefied (oiled) and recycled as fuels or the like, an exothermic reaction or an endothermic reaction occurs depending on the type of waste plastics. Therefore, in the thermal decomposition treatment of waste plastics, it is important to determine the specifications of an appropriate heating device according to the waste plastics to be thermally decomposed.

[0006] This disclosure aims to provide a method for estimating the heat of chemical reaction of polymer compounds containing repeating units such as waste plastics, and a method for thermal decomposition treatment of waste plastics. [Means for solving the problem]

[0007] The above problems will be solved by the following means. <1> To represent the chemical reaction of a polymer compound containing repeating units containing carbon and hydrogen in units of molecular constituents smaller than the repeating unit, The standard enthalpy of formation of the aforementioned molecular constituent units is estimated stoichiometrically using known data on the heat of complete combustion, and Based on the estimated standard enthalpy of formation of the aforementioned molecular constituent units, the amount of endothermic and exothermic reactions of the polymer compound is estimated. A method for estimating the heat of chemical reaction of polymer compounds containing polymers. <2> The aforementioned molecular constituent units are defined as constituent units per mole of carbon. <1> A method for estimating the heat of chemical reaction of polymer compounds described above. <3> The polymer compound is polymer compound A, which contains element X other than carbon, hydrogen, and oxygen in its repeating units, and when estimating the standard enthalpy of formation of the constituent units per mole of carbon in polymer compound A, For polymer compound B, which includes repeating units of the structure obtained by replacing element X of polymer compound A with hydrogen or oxygen, the standard enthalpy of formation of the constituent unit per mole of carbon is estimated stoichiometrically using known data of the heat of complete combustion, and The standard enthalpy of formation of the constituent units per mole of carbon in polymer compound A is calculated by correcting the estimated standard enthalpy of formation of the constituent units per mole of carbon in polymer compound B using the difference between the standard enthalpy of formation of the constituent units per mole of carbon in monomolecule a corresponding to the repeating unit of polymer compound A and the standard enthalpy of formation of the constituent units per mole of carbon in monomolecule b corresponding to the repeating unit of polymer compound B. including, <2> A method for estimating the heat of chemical reaction of polymer compounds described above. <4> The polymer compound is polymer compound D, which contains a carbon double bond in the main chain of the repeating unit, and when estimating the standard enthalpy of formation of a constituent unit per mole of carbon in polymer compound D, For polymer compound E, which includes a repeating unit in which two carbon atoms are single-bonded and hydrogen is bonded to each carbon atom, the standard enthalpy of formation of the constituent unit per mole of carbon is estimated stoichiometrically using known data of the heat of complete combustion, and The standard enthalpy of formation of the constituent units per mole of carbon in polymer compound D is calculated by correcting the estimated standard enthalpy of formation of the constituent units per mole of carbon in polymer compound E using the difference between the standard enthalpy of formation of the constituent units per mole of carbon in monomolecule d corresponding to the repeating unit of polymer compound D and the standard enthalpy of formation of the constituent units per mole of carbon in monomolecule e corresponding to the repeating unit of polymer compound E. including, <2> A method for estimating the heat of chemical reaction of polymer compounds described above. <5> A method for thermally decomposing waste plastics using a heating device, <1> ~ <4> To estimate the heat of reaction in the thermal decomposition treatment of the waste plastic using the method for estimating the heat of chemical reaction of polymer compounds described in any one of the following: Based on the estimated value of the reaction heat, the specifications of the heating device are determined, and The heating device with the specified specifications is used to perform thermal decomposition treatment of waste plastics. A method for thermal decomposition treatment of waste plastics, including those containing [unspecified material]. [Effects of the Invention]

[0008] This disclosure provides a method for estimating the heat of chemical reaction of polymer compounds containing repeating units such as waste plastics, and a method for thermal decomposition treatment of waste plastics. [Brief explanation of the drawing]

[0009] [Figure 1] It is a diagram showing an example of a method for calculating the standard enthalpy of formation per mole of carbon in benzene. [Figure 2] It is a diagram showing an example of a method for calculating the standard enthalpy of formation per mole of carbon in polypropylene. [Figure 3] It is a diagram showing an example of a method for calculating the standard enthalpy of formation per mole of carbon in polyvinyl alcohol. [Figure 4] It is a diagram showing the debenzene reaction formula and enthalpy balance of polystyrene. [Figure 5] It is a diagram showing the dehydrochlorination reaction formula and enthalpy balance of polyvinyl chloride.

Embodiments for Carrying out the Invention

[0010] A method for estimating the heat of chemical reaction of a polymer compound according to the present disclosure and a method for thermally decomposing waste plastic (hereinafter, may be abbreviated as "the estimation method of the present disclosure") will be described.

[0011] When determining the heat absorption or release of a certain reaction, it is common to evaluate the increase or decrease in the standard enthalpy of formation for the substances before and after the reaction. Waste plastic is a mixture composed of various polymer compounds (plastics). However, there is no concept of evaluating polymer compounds in terms of the enthalpy of formation, nor is there a definition of the enthalpy of formation. Therefore, no matter how many physical property value tables are investigated, there is no literature that describes the enthalpy of formation for polymer compounds such as PE, PP, PS, PVC, and PET, which are typical components of waste plastic. What is usually described in the physical property value table of polymer compounds is only the heat of complete combustion.

[0012] On the one hand, the dechlorination treatment process of waste plastics containing chlorine such as PVC is generally a process that promotes, for example, the thermal decomposition reaction of PVC by maintaining a high temperature and an oxygen-free state while kneading. Therefore, it is impossible to quantitatively evaluate the heat absorption and evolution behavior due to such a thermal decomposition reaction only with the information of the complete combustion heat. It is considered that the temperature control of the high-temperature holding process necessary for smoothly proceeding with dechlorination can be realized only when the heat absorption and evolution behavior of the thermal decomposition reaction can be quantitatively evaluated. For this reason, it is desirable to find a method for quantitatively evaluating the degree of heat absorption and evolution of the thermal decomposition reaction of the constituent materials of various waste plastics (especially PET, PVC, PVDC).

[0013] When evaluating the heat of thermal decomposition reaction or the heat of incomplete combustion of polymer compounds such as waste plastics, it is very advantageous to use the standard formation enthalpy instead of the complete combustion heat because stoichiometric evaluation before and after the reaction becomes possible.

[0014] Therefore, the inventors of the present disclosure have studied a method for effectively utilizing physical property value information such as the complete combustion heat of polymer compounds, and as a result of attempting to devise a method for estimating a physical property value corresponding to the standard formation enthalpy for polymer compounds, they have found a method for estimating the heat of chemical reaction of the polymer compounds according to the present disclosure. That is, the method for estimating the heat of chemical reaction of the polymer compounds according to the present disclosure represents the chemical reaction of a polymer compound containing a repeating unit containing carbon and hydrogen in molecular constituent units below the repeating unit, chemically and stoichiometrically estimates the standard formation enthalpy of the molecular constituent units using known data of the complete combustion heat, and estimates the amount of heat absorption and evolution of the chemical reaction of the polymer compound based on the estimated value of the standard formation enthalpy of the molecular constituent units.

[0015] Note that examples of the known data of the complete combustion heat include literature data, experimental data, and the like. This method allows for the estimation of the standard enthalpies of formation of each substance before and after a chemical reaction involving polymer compounds, thereby enabling a proper evaluation of the reaction heat. As a result, it becomes possible to provide important information for determining appropriate heating equipment specifications when designing a process for the thermal decomposition of these polymer compounds.

[0016] The method for estimating the heat of chemical reaction of polymer compounds according to this disclosure involves reducing the molecular components of the polymer compound to a level where a stoichiometric reaction equation can be easily constructed, and defining the enthalpy of formation at the molecular component level. The estimation method in this disclosure is fundamentally based on this idea. Since polymer compounds are generally composed of carbon, ultimately, if it can be converted to the "standard enthalpy of formation per mole of carbon," it will be possible to apply this method to the reaction evaluation of many polymer compounds.

[0017] For example, while it is not necessary to convert to the "standard enthalpy of formation per mole of carbon" for monomolecules, we will use benzene as an example to explain how to convert to the "standard enthalpy of formation per mole of carbon" from the heat of combustion of hydrocarbon compounds. Figure 1 shows an example of how to calculate the standard enthalpy of formation per mole of carbon, using benzene as an example. The molecular formula of benzene is originally C6H6, but when expressed per mole of carbon, it becomes CH, as shown in the "complete combustion stoichiometric formula" in Figure 1. Based on this stoichiometric formula, the standard enthalpy of formation of oxygen is "0", so the balance equation for the complete combustion reaction can be expressed by equation (1) in Figure 1. Then, by rearranging equation (1), we can obtain the "standard enthalpy of formation per mole of carbon" for benzene.

[0018]

number

[0019] This can be expressed by equation (2) in Figure 1. That is, the enthalpy of formation of benzene is [1] Higher heating of benzene per mole of carbon

[0020]

number

[0021] If it is known, [2] Standard enthalpy of carbon dioxide production

[0022]

number

[0023] [3] Standard enthalpy of water

[0024]

number

[0025] It can be uniquely determined using [this method].

[0026] Similarly, for polymer compounds, if the heat of complete combustion is known, then the values ​​of [2] and [3] are also known, making it possible to determine the "standard enthalpy of formation per mole of carbon".

[0027] In the example of benzene (equation (2) in Figure 1), the coefficient of the enthalpy of water formation is "1 / 2," but in the case of polymer compounds, this coefficient changes depending on the type of polymer compound. For example, if the molecular formula per mole of carbon in a certain polymer compound is CH m O l When expressed as such, the coefficient of the enthalpy of water formation is "m / 2".

[0028] Standard enthalpy of formation is defined as the energy required to decompose a polymer into its basic constituent elements (C, H2, O2, N2, S) under standard conditions (where the standard enthalpy of formation is zero). Therefore, the standard enthalpy of formation calculated by equation (2) can be considered as the "pure decomposition heat per mole of carbon (kJ / mol)" of the polymer compound. For reference, using this method, the "standard enthalpy of formation per mole of carbon" calculated from the combustion heat per mole of carbon in benzene (544.5 kJ / mol) is 8.03 kJ / mol. Therefore, converting this to units of the molecular formula C6H6 and multiplying by 6 gives 48.18 kJ / mol. This value roughly matches the literature value of 49.0 kJ / mol for the standard enthalpy of formation of benzene.

[0029] <Method for calculating the "standard enthalpy of formation per mole of carbon" for polypropylene> Next, we will take polypropylene (PP) as a specific polymer compound and illustrate the estimation method of this disclosure. Figure 2 shows the molecular structure of polypropylene and illustrates the method for calculating the "standard enthalpy of formation per mole of carbon" of polypropylene. The molecular structure of polypropylene is a structure in which many constituent units are linked together, with a basic structure of 3 carbon atoms (C) and 6 hydrogen atoms (H) as one unit (structural unit). Therefore, when rewritten in terms of the molecular structure per mole of carbon, it can be expressed as a stoichiometric formula of 1 carbon atom (C) and 2 hydrogen atoms (H), so the formula for complete combustion is the expression CH2 as shown in Figure 2. Accordingly, the heat balance equation for the complete combustion reaction can be expressed by equation (3).

[0030] By manipulating equation (3) in the same manner as shown in Figure 1, the "standard enthalpy of formation per mole of carbon" for the molecular structure of polypropylene can be expressed by equation (4) in Figure 2. According to known data described in "Hideo Oe and Koichi Matsuura: "On the heat of combustion and oxygen index of polymer materials," Research Reports of the Faculty of Engineering, Fukui University, Vol. 23, No. 2, pp. 161-169 (1975)," the total heat of combustion of polypropylene is 11030 kcal / kg. Converting this to kJ, and using the molecular formula CH2, the total heat of combustion per mole of carbon can be calculated.

[0031]

number

[0032] Converted to this, it becomes 646.4 kJ / mol. In this calculation, the atomic weight of C is assumed to be 12 and the atomic weight of H is assumed to be 1. Therefore, this is the heat of complete combustion.

[0033]

number

[0034] Substituting this, along with the known standard enthalpy of formation of carbon dioxide and the standard enthalpy of formation of water, into equation (4), we obtain the "standard enthalpy of formation per mole of carbon".

[0035]

number

[0036] Calculating this yields -33.0 kJ / mol. Here, if we want to evaluate the heat of reaction using the standard enthalpy of formation of the molecular structural unit C3H6 shown in Figure 2, rather than per mole of carbon, we can calculate it by multiplying this value by 3 (i.e., -99.0 kJ / mol).

[0037] <Method for calculating the "standard enthalpy of formation per mole of carbon" of polyvinyl alcohol> Similarly, Figure 3 shows an example of calculating the "standard enthalpy of formation per mole of carbon" for polyvinyl alcohol. In this case, oxygen is added to the polymer compound, but it can be seen that the basic calculation method is exactly the same as in Figure 2. According to known data described in "Hideo Oe and Koichi Matsuura: "On the heat of combustion and oxygen index of polymer materials," Research Reports of the Faculty of Engineering, Fukui University, Vol. 23, No. 2, pp. 161-169 (1975)," the total heat of combustion of polyvinyl alcohol is 5990 kcal / kg. Molecular formula CH2O per mole of carbon 0.5 As such, the heat of complete combustion per mole of carbon

[0038]

number

[0039] Converted to this, it becomes 551.6 kJ / mol. At this time, the atomic weight of C is assumed to be 12, the atomic weight of H to be 1, and the atomic weight of O to be 16. Therefore, this is the heat of complete combustion.

[0040]

number

[0041] Substituting this, along with the known standard enthalpy of formation of carbon dioxide and the standard enthalpy of formation of water, into equation (6), we obtain the "standard enthalpy of formation per mole of carbon" for polyvinyl alcohol.

[0042]

number

[0043] Calculating this gives us -127.8 kJ / mol.

[0044] In each of the above examples, the polymer compound is composed of C, H, or C, H, and O, and only CO2 and H2O are produced by the heat of complete combustion. On the other hand, in cases where the polymer compound contains elements that do not participate in combustion, such as chlorine (Cl), in the bonding elements, such as PVC and PVDC, applying the complete combustion rate formula would necessitate assuming the production of chlorine compounds (chlorine gas, hydrogen chloride, etc.) after the combustion reaction. Since the accuracy of this assumption is questionable, it is possible that the estimation accuracy of the "standard enthalpy of formation per mole of carbon" will be greatly reduced if the estimation method remains based on the complete combustion rate formula. Therefore, for polymer compounds such as polymer chlorides containing chlorine and unsaturated polymer compounds containing carbon double bonds (e.g., PVC, PVDC, polyacetylene, polyacetylene chloride), the "standard enthalpy of formation per mole of carbon" can be estimated by relative evaluation from the difference in values ​​between two monomolecules with similar molecular structures. Specifically, this is as follows.

[0045] (In the case of polymer compounds containing element X other than carbon, hydrogen, and oxygen) When a polymer compound is polymer compound A, which contains elements X other than carbon, hydrogen, and oxygen in its repeating units, in estimating the standard enthalpy of formation of the constituent units per mole of carbon in polymer compound A, For polymer compound B, which contains repeating units of a structure in which element X of polymer compound A is replaced with hydrogen or oxygen, the standard enthalpy of formation of the constituent unit per mole of carbon was estimated stoichiometrically using known data on the heat of complete combustion. The standard enthalpy of formation of a component unit per mole of carbon in polymer compound A is calculated by using the estimated standard enthalpy of formation of a component unit per mole of carbon in polymer compound B as a baseline, and correcting it using the difference between the standard enthalpy of formation of a component unit per mole of carbon in monomolecule a, which corresponds to the repeating unit of polymer compound A, and the standard enthalpy of formation of a component unit per mole of carbon in monomolecule b, which corresponds to the repeating unit of polymer compound B.

[0046] <Method for calculating the "standard enthalpy of formation per mole of carbon" of polyvinyl chloride> For example, the "standard enthalpy of formation per mole of carbon" for polyvinyl chloride (PVC) is calculated by taking the "standard enthalpy of formation per mole of carbon" value for polyethylene as a baseline and adding the difference in "standard enthalpy of formation per mole of carbon" between ethane and chloroethane. In other words, the standard enthalpy of formation per mole of carbon in polyethylene, calculated using the same method as for polypropylene in Figure 2, is -28.9 kJ / mol. On the other hand, the standard enthalpies of formation of ethane and chloroethane, as found in general physical property tables, are -84.7 kJ / mol and -109.0 kJ / mol, respectively. Therefore, when converted to the standard enthalpy of formation per mole of carbon, these are -42.3 kJ / mol and -54.5 kJ / mol, respectively. Thus, the standard enthalpy of formation per mole of carbon in PVC can be calculated as -28.9 + (-54.5 + 42.3) = -41.1 kJ / mol.

[0047] (In the case of polymer compounds containing carbon double bonds in the main chain of repeating units) When a polymer compound is polymer compound D, which contains carbon double bonds in the repeating main chain, in estimating the standard enthalpy of formation of a constituent unit per mole of carbon in polymer compound D, For polymer compound E, which contains repeating units of a structure in which two carbon atoms are single-bonded and each carbon atom is bonded to a hydrogen atom, the standard enthalpy of formation of the constituent unit per mole of carbon was estimated stoichiometrically using known data on the heat of complete combustion. The standard enthalpy of formation of a component unit per mole of carbon in polymer compound D is calculated by using the estimated standard enthalpy of formation of a component unit per mole of carbon in polymer compound E as a reference, and correcting it using the difference between the standard enthalpy of formation of a component unit per mole of carbon in monomolecule d corresponding to the repeating unit of polymer compound D and the standard enthalpy of formation of a component unit per mole of carbon in monomolecule e corresponding to the repeating unit of polymer compound E.

[0048] <Method for calculating the "standard enthalpy of formation per mole of carbon" of polyacetylene> For polymer compounds containing double bonds, such as polyacetylenes and polychlorinated acetylenes, it is difficult to find combustion heat data. In such cases, calculating the "standard enthalpy of formation per mole of carbon" by relatively evaluating two similar monomolecules is a very effective method. In other words, the standard enthalpy of formation per mole of carbon for polyethylene is -28.9 kJ / mol. On the other hand, looking up the standard enthalpies of formation for ethane and ethylene from a general physical property table, we find them to be -84.7 kJ / mol and 52.4 kJ / mol, respectively. Converting these to standard enthalpy of formation per mole of carbon, we get -42.3 kJ / mol and 26.2 kJ / mol, respectively. Therefore, the standard enthalpy of formation per mole of carbon for polyacetylene can be calculated as -28.9 + (26.2 + 42.3) = 39.6 kJ / mol.

[0049] Table 1 summarizes the results of determining the "standard enthalpy of formation per mole of carbon" for representative polymer compounds using the methods described above.

[0050] [Table 1]

[0051] Table 2 also shows, for reference, the standard enthalpy of formation per mole of carbon for several monomolecules. These values ​​were basically taken from the NIST (National Institute of Standards and Technology) physical property tables.

[0052] [Table 2]

[0053] [Evaluation of endothermic and exothermic reactions of polymer compounds] Using the "standard enthalpy of formation per mole of carbon in polymer compounds" calculated by the methods described above, we will now present a method for evaluating the endothermic and exothermic effects of a reaction. Heat of reaction in a certain reaction equation

[0054]

number

[0055] The estimation formula, expressed in common notation, is as shown in equation (7).

[0056]

number

[0057] Here, the first term on the right-hand side is the sum of the enthalpies of formation of the products on the right-hand side of the stoichiometric equation, and the second term on the right-hand side is the sum of the enthalpies of formation of the reactants on the left-hand side of the stoichiometric equation. i and α i These are coefficients applied to substance i on the product side and reactant side, respectively, when expressed in stoichiometric formulas. (Third term on the right-hand side)

[0058]

number

[0059] This term considers the phase change heat effect when a product, which is solid or liquid under standard conditions, sublimes or evaporates. It is considered positive when a phase change occurs. The third term on the right-hand side is enclosed in double parentheses to indicate that it may or may not be considered. Heat of reaction

[0060]

number

[0061] If the value is positive, it indicates an endothermic reaction; if it is negative, it indicates an exothermic reaction. Furthermore, its absolute value represents the amount of heat [kJ / mol].

[0062] <Desorption reaction of a benzene ring from polystyrene> Figure 4 shows an example of evaluating the heat of reaction for the elimination of a benzene ring from polystyrene. The upper part of Figure 4 shows the chemical equation, and the lower part shows the enthalpy balance (result of equation (7)) based on the "standard enthalpy of formation per mole of carbon" that corresponds to it. The value of "standard enthalpy of formation per mole of carbon" in the lower part of Figure 4 is the value from Table 1 or Table 2, rounded to one decimal place. As a result of the enthalpy balance, it can be seen that the reaction changing from the left side to the right side of this chemical equation is an endothermic reaction of (8 × 3 / 4 + 40 / 4 + 3) = 19 kJ / mol. The molecular formula of polystyrene per mole of carbon is CH, so the molecular weight is 13. Therefore, when designing a reactor for this reaction system, it can be seen that an endothermic reaction of 19 / 13 = approximately 1.5 kJ / g should be expected.

[0063] <Desorption reaction of hydrogen chloride from polyvinyl chloride> Similarly, Figure 5 shows an example of evaluating the heat of reaction for the elimination of hydrogen chloride from PVC. The upper part of Figure 5 shows the chemical equation, and the lower part of Figure 5 shows the enthalpy balance (result of equation (7)) at the "standard enthalpy of formation per mole of carbon" corresponding to it. The value of "standard enthalpy of formation per mole of carbon" in the lower part of Figure 5 is the value from Table 1 or Table 2, rounded to one decimal place. As a result of the enthalpy balance, it can be seen that the reaction changing from the left side to the right side of this chemical equation is an endothermic reaction with a heat of (40-92 / 2+41)=35kJ / mol. The molecular formula per mole of carbon in PVC is CH 3 / 2 Cl 1 / 2 Therefore, the molecular weight is (12 + 1.5 + 35.5 / 2) = 31. Consequently, when designing a reactor for this reaction system, an endothermic reaction of approximately 1.1 kJ / g (35 / 31) should be anticipated.

[0064] This disclosure provides a method for estimating the standard enthalpy of formation per mole of carbon in various polymer compounds, and makes it possible to estimate the heat of reaction for chemical reactions involving polymer compounds. As a result, for example, when constructing a process for thermally decomposing waste plastics, which are polymer compounds, it becomes possible to determine the specifications of an appropriate heating device and perform thermal decomposition of waste plastics. [Examples]

[0065] The following describes examples of the method for estimating the heat of chemical reaction of polymer compounds according to this disclosure. However, the method for estimating the heat of chemical reaction of polymer compounds according to this disclosure is not limited in any way to the examples described below.

[0066] [Determining the appropriate heating capacity for the reaction to dechlorinate PVC contained in waste plastics] <Method> We designed a process to dechlorinate waste plastics by heating and kneading them, thereby thermally decomposing the PVC contained in the waste plastics. In other words, we evaluated the amount of heating required to advance the dechlorination reaction shown in Figure 5. In the case of the reaction equation in Figure 5, the result of the calculation in equation (7) is that the dechlorination reaction is,

[0067]

number

[0068] This is an endothermic reaction. Here, assuming there is no phase change,

[0069]

number

[0070] It is set to zero. If the processing rate of waste plastic is W [kg / s], then the heat of PVC pyrolysis

[0071]

number

[0072] This can be expressed by equation (8) below.

[0073]

number

[0074] Here,

[0075]

number

[0076] This is the heat absorption [kJ / mol] of PVC thermal decomposition.

[0077]

number

[0078] This is the molecular weight per mole of carbon in PVC (=31).

[0079]

number

[0080] This represents the mass ratio of PVC that has been thermally decomposed within all discarded plastics.

[0081] The required waste plastic processing speed is W = 3~4 t / hr = 0.83~1.11 kg / s.

[0082]

number

[0083] Assuming this is the case, substitute these values ​​into equation (8) to obtain the heat of PVC pyrolysis.

[0084]

number

[0085] When evaluating,

[0086]

number

[0087] It was found that this corresponds to the amount of heat absorbed.

[0088] <Result> This dechlorination process required raising the temperature to a maximum of 350°C. Therefore, in addition to the thermal influence [kW] that should be added as heating capacity, such as the moisture content, sensible heat, and latent heat of fusion of the waste plastic, the heat of PVC pyrolysis was also considered.

[0089]

number

[0090] By incorporating the estimated thermal effects, we were able to implement an appropriate process design.

[0091] The method for estimating the heat of chemical reaction of polymer compounds and the method for thermal decomposition treatment of waste plastics according to this disclosure are not limited to the embodiments and examples described above. For example, the molecular constituent units are not limited to constituent units per mole of carbon, and the repeating units of the polymer compound may be used as molecular constituent units, and the standard enthalpy of formation of the repeating units may be estimated stoichiometrically using known data of the heat of complete combustion.

Claims

1. To represent the chemical reaction of a polymer compound containing repeating units containing carbon and hydrogen in units of molecular constituents smaller than the repeating unit, The standard enthalpy of formation of the aforementioned molecular constituent units is estimated stoichiometrically using known data on the heat of complete combustion, and Based on the estimated standard enthalpy of formation of the aforementioned molecular constituent units, the amount of endothermic and exothermic reactions of the polymer compound is estimated. A method for estimating the heat of chemical reaction of polymer compounds containing polymers.

2. A method for estimating the heat of chemical reaction of a polymer compound according to claim 1, wherein the molecular constituent unit is defined as the constituent unit per mole of carbon.

3. The polymer compound is polymer compound A, which contains element X other than carbon, hydrogen, and oxygen in its repeating units, and when estimating the standard enthalpy of formation of the constituent units per mole of carbon in polymer compound A, For polymer compound B, which includes repeating units of the structure obtained by replacing element X of polymer compound A with hydrogen or oxygen, the standard enthalpy of formation of the constituent unit per mole of carbon is estimated stoichiometrically using known data of the heat of complete combustion, and The standard enthalpy of formation of the constituent units per mole of carbon in polymer compound A is calculated by correcting the estimated standard enthalpy of formation of the constituent units per mole of carbon in polymer compound B using the difference between the standard enthalpy of formation of the constituent units per mole of carbon in monomolecule a corresponding to the repeating unit of polymer compound A and the standard enthalpy of formation of the constituent units per mole of carbon in monomolecule b corresponding to the repeating unit of polymer compound B. A method for estimating the heat of chemical reaction of a polymer compound according to claim 2, including the method described in claim 2.

4. The polymer compound is polymer compound D containing a carbon double bond in the main chain of the repeating unit, and when estimating the standard enthalpy of formation of a constituent unit per mole of carbon in polymer compound D, For polymer compound E, which includes a repeating unit in which two carbon atoms are single-bonded and hydrogen is bonded to each carbon atom, the standard enthalpy of formation of the constituent unit per mole of carbon is estimated stoichiometrically using known data of the heat of complete combustion, and The standard enthalpy of formation of the constituent units per mole of carbon in polymer compound D is calculated by correcting the estimated standard enthalpy of formation of the constituent units per mole of carbon in polymer compound E using the difference between the standard enthalpy of formation of the constituent units per mole of carbon in monomolecule d corresponding to the repeating unit of polymer compound D and the standard enthalpy of formation of the constituent units per mole of carbon in monomolecule e corresponding to the repeating unit of polymer compound E. A method for estimating the heat of chemical reaction of a polymer compound according to claim 2, including the method described in claim 2.

5. A method for thermally decomposing waste plastics using a heating device, To estimate the reaction heat in the thermal decomposition treatment of the waste plastic by the method for estimating the chemical reaction heat of a polymer compound described in any one of claims 1 to 4, Based on the estimated value of the reaction heat, the specifications of the heating device are determined, and The heating device with the specified specifications is used to perform thermal decomposition treatment of waste plastics. A method for thermal decomposition treatment of waste plastics, including those containing [unspecified material].

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