Method for Enhancing Incinerator Combustion Efficiency using Eco-Friendly Combustion Additive Composition

Abstract

The present invention relates to an eco-friendly combustion improver composition comprising purified water, sodium carbonate, sorbitol, cerium oxide, polylactic acid, and potassium sorbate, and a method for improving combustion efficiency and reducing harmful gas emissions by applying the same to an incineration plant. In particular, the present invention flexibly responds to real-time combustion conditions by automatically controlling the composition and injection conditions of the combustion improver according to the difference between temperature data received from a TMS system and reference temperature data, thereby simultaneously achieving inhibition of clinker formation, slag fluidization, dust reduction, and improved storage stability.

Description

Technology Field

[0001] The present invention relates to a method for improving combustion efficiency in an incinerator using a combustion improvement agent composition applicable to a waste incinerator, and more specifically, to a method for improving combustion efficiency in an incinerator using an eco-friendly combustion improvement agent composition that reduces NOx and CO emissions, facilitates slag fluidization, and simultaneously provides dust reduction and long-term storage stability. Background Technology

[0002] In general, various types of waste are processed at incineration plants, generating large quantities of harmful gases such as NOx and CO during the process. Conventional combustion improvers have focused on single functions, such as slag reduction or catalytic NOx reduction, and have faced limitations in terms of environmental friendliness and long-term storage stability. In particular, the frequent use of expensive precious metal catalysts or toxic preservatives has limited their application in public incineration facilities. Furthermore, there is a lack of development in compositions equipped with complex functions that simultaneously improve combustion efficiency. Meanwhile, existing combustion improver injection methods rely on fixed injection volumes or manual injection, which fail to respond flexibly to real-time changes in combustion conditions and cause problems such as fluctuations in calorific value and clinker formation. Prior art literature

[0003] Republic of Korea Registered Patent No. 10-1415454 Republic of Korea Published Patent No. 10-2019-0000337 The problem to be solved

[0004] The present invention was devised to solve the problems of the conventional technology described above, and aims to provide an eco-friendly combustion improvement agent composition composed of biodegradable and non-toxic substances that reduces the emission of harmful gases such as NOx and CO, fluidizes slag, and effectively suppresses dust generated during combustion, while enabling long-term storage.

[0005] Furthermore, we aim to simultaneously achieve clinker suppression, improved combustion stability, prevention of excessive chemical injection, and cost reduction through an automated system capable of controlling the injection amount and composition of combustion improvers and calorific value enhancing additives based on real-time temperature data. means of solving the problem

[0006] A combustion improver according to the present invention for achieving the above-mentioned purpose comprises 70 to 84 weight% purified water, 10 to 15 weight% sodium carbonate, 5 to 12 weight% sorbitol, 0.3 to 1.5 weight% cerium oxide, 0.5 to 2 weight% polylactic acid, and 0.2 to 1 weight% potassium sorbate.

[0008] And, the combustion efficiency improvement method according to the present invention comprises (a) transferring a combustion improver containing purified water, sodium carbonate, sorbitol, cerium oxide, polylactic acid, and potassium sorbate from a combustion improver storage tank to a main supply stirring tank, (b) storing a calorific value improving additive in a separate storage stirring tank, (c) comparing real-time temperature data of an incinerator with a reference temperature and, if the temperature difference is 50℃ or less, injecting only the combustion improver, and (d) if the temperature difference exceeds 50℃, introducing the calorific value improving additive into the main supply stirring tank, stirring for a certain period of time, and then injecting the mixture.

[0010] Here, the combustion improver comprises 70 to 84 weight% purified water, 10 to 15 weight% sodium carbonate, 5 to 12 weight% sorbitol, 0.3 to 1.5 weight% cerium oxide, 0.5 to 2 weight% polylactic acid, and 0.2 to 1 weight% potassium sorbate, and the calorific value enhancing additive comprises an aqueous solution of glycerin or sorbitol. Effects of the invention

[0011] The combustion improvement agent composition according to the present invention, as described above, effectively suppresses the emission of major harmful gases generated during combustion by performing various functions in combination, and improves the combustion efficiency of incineration facilities by simultaneously providing slag fluidization and dust reduction effects. Furthermore, due to the storage stability and biodegradability of the composition, it is environmentally friendly and suitable for long-term use. Moreover, by improving the injection method through the controlled injection system of the present invention, the amount of additive injected is automatically adjusted according to real-time combustion conditions, thereby suppressing clinker formation and minimizing energy loss, which has the advantage of improving overall incineration efficiency and heat recovery rate. Brief explanation of the drawing

[0012] FIG. 1 is a configuration diagram of a controlled combustion improver injection system according to the present invention. Specific details for implementing the invention

[0013] Hereinafter, the composition and operation of the combustion improvement agent composition according to the present invention and the method for improving combustion efficiency of an incineration plant using the same will be described in detail with reference to the attached drawings and preferred embodiments.

[0015] The combustion improver composition of the present invention comprises purified water, sodium carbonate (Na2CO3), sorbitol, cerium oxide (CeO2), polylactic acid (PLA), and potassium sorbate.

[0017] Sodium carbonate neutralizes acidic gases and contributes to the reduction of slag viscosity. Specifically, at high temperatures, Na2CO3 reacts with internal ash to lower the viscosity of the molten slag, thereby fluidizing it, and contributes to corrosion prevention by neutralizing acidic gases (HCl, SO2, etc.). The main reaction equations are as follows.

[0018] Na 2 CO 3 + 2HCl → 2NaCl + H 2 O + CO 2 ↑

[0019] It is preferable that the content of the sodium carbonate in the composition be 10 to 15 weight percent. If the content of sodium carbonate (Na2CO3) is less than 10 weight percent, there is a risk that the acid gas reduction effect will be reduced because there is insufficient alkali capacity to effectively neutralize acidic gases, such as hydrochloric acid (HCl) or sulfur dioxide (SO2), generated during waste incineration. In addition, the function of lowering the melting point of the slag and reducing viscosity to induce slag fluidization is not sufficiently exerted, which may result in the formation of solidified or sticky slag. On the other hand, if the sodium carbonate content exceeds 15 weight percent, the pH of the composition rises excessively, which may reduce the chemical stability of other major additives, such as cerium oxide or polylactic acid, and crystallization phenomena that impair the uniformity of the entire composition may occur. In particular, high concentrations of sodium carbonate cause precipitation or phase separation during storage, which has a negative impact on long-term storage stability. In addition, the excessive use of sodium carbonate is undesirable in terms of raw material costs as it reduces the economic efficiency of the composition.

[0021] Sorbitol creates a reducing atmosphere and provides exothermic properties. Specifically, the sorbitol is a polyhydric alcohol that provides temperature stability through a rapid exothermic reaction upon combustion and contributes to the suppression of NOx generation by creating a reducing atmosphere.

[0022] Example: CO·H2 generation → NOx reduction:

[0023] NO + CO → ½N2 + CO2

[0024] NO + H2 → ½N2 + H2O

[0025] It is preferable that the content of the sorbitol in the composition be 5 to 12 weight percent. If the sorbitol content is less than 5 weight percent, the contribution to the total calorific value of the composition is low, resulting in insufficient actual combustion assistance function and insufficient induction of a reducing atmosphere, which also reduces the NOx reduction effect. Furthermore, the viscosity-improving effect required to induce dust aggregation or surface adhesion is weakened, limiting synergy in terms of improving incineration efficiency. Conversely, if the sorbitol content exceeds 12 weight percent, excessive heat generation makes it difficult to control the internal temperature of the incinerator, and the excess reducing gas may increase CO concentration and the possibility of incomplete combustion. Additionally, excessive viscosity may degrade the spraying characteristics of the composition, or cause adhesion phenomena during stirring and conveying processes, leading to operational problems with the equipment. Moreover, a high concentration of organic matter may negatively affect the storage stability of the composition and is inefficient in terms of raw material costs.

[0027] Cerium oxide assists in NOx reduction and CO oxidation through selective redox cycles. Specifically, CeO2 is Ce 3+ / Ce 4+It selectively reduces NOx through redox cycles or suppresses incomplete combustion through O2 storage / supply functions. It also acts as a catalyst to assist in the oxidation of CO and carbides. It is preferable that the cerium oxide content in the composition be 0.3 to 1.5 wt%. If the cerium oxide content is less than 0.3 wt%, the amount of CeO₂ in the composition is absolutely insufficient, so the effects of NOx reduction and CO oxidation promotion do not appear significantly. On the other hand, if the CeO₂ content exceeds 1.5 wt%, while the additional NOx reduction effect stagnates, problems such as increased cost of the composition, reduced dispersion stability, and increased viscosity occur. In particular, since cerium oxide exists in the form of fine particles, using a high content increases the likelihood of aggregation or precipitation within the composition, which may reduce long-term storage stability and raise concerns about process issues such as nozzle clogging during injection. Furthermore, at 1.5% or higher, no significant additional improvement in the NOx reduction rate is observed.

[0029] Polylactic acid (PLA) exhibits an effect of enhancing adhesion and aggregating dust particles during the pre-combustion stage. It is a biodegradable polymer that decomposes into CO2 and H2O without leaving residue and produces low smoke emissions during combustion. It is preferable that the content of polylactic acid (PLA) in the composition be 0.5 to 2 weight percent. If the PLA content is less than 0.5 weight percent, the adhesion and aggregation effects are not sufficiently exhibited, and dust or re-entrained fine particles generated during the combustion process may not be effectively controlled. Consequently, the dust reduction effect is negligible, which may lead to reduced combustion efficiency and place a load on downstream dust collection equipment. In particular, since the dust aggregation function is related to the dispersion stability of inorganic particles such as CeO₂, a minimum of 0.5 weight percent can be considered the critical lower limit for the function to be exhibited. Conversely, if the PLA content exceeds 2 weight%, the viscosity of the composition increases excessively, which may cause physical problems such as nozzle clogging and uneven stirring in the injection equipment, and also have a negative effect on mixing stability. In addition, an excessive amount of polymer components increases the likelihood of gelation during storage of the composition and is a factor that reduces economic efficiency. Furthermore, excessive tackiness may cause slag adhesion or wall contamination in the combustion chamber, which can have an adverse effect on combustion stability.

[0031] Potassium sorbate provides long-term storage stability by inhibiting microorganisms. Specifically, the potassium sorbate inhibits the growth of mold and yeast in an aqueous solution within a pH range of 6 to 9. It is preferable that the potassium sorbate content in the composition be 0.2 to 1 weight percent. If the potassium sorbate is less than 0.2 weight percent, the growth of microorganisms such as bacteria or mold is not inhibited during long-term storage due to insufficient preservation of the entire composition. In particular, physical instability such as changes in physical properties, aggregation of fine particles, and separation of layers may occur during the hot and humid summer months or when stored for a long period after opening. Since this can lead to a deterioration in the quality and loss of performance of the composition, a minimum of 0.2 weight percent can be considered the critical lower limit for effective antibacterial action. Conversely, if it exceeds 1 weight percent, not only is the cost burden increased due to the excessive input of potassium sorbate, but side effects may also occur, such as impaired chemical stability of the composition, induction of pH changes, and a weak irritating odor upon spraying, due to interactions with certain additives. In addition, the possibility of preservative residue increases upon environmental release, so it needs to be considered in terms of ecotoxicity.

[0033] Purified water acts as a medium for the uniform mixing of all components, and its content is preferably 70 to 84 weight percent. If the content of purified water is less than 70 weight percent, the viscosity of the overall composition increases, which may cause nozzle clogging in the spraying equipment, lead to uneven stirring and conveying, and reduce solid dispersion. Additionally, inorganic components such as sodium carbonate and cerium oxide may exceed their saturation solubility, increasing the likelihood of precipitation or crystallization, which can adversely affect storage stability. Conversely, if the content of purified water exceeds 84 weight percent, the composition becomes excessively diluted, reducing the concentration of the active ingredient per unit volume during spraying. Consequently, the concentration required to achieve actual function when introduced into an incinerator is insufficient. For instance, the functional efficiency of the composition is reduced in terms of NOx reduction, heat generation assistance, and dust aggregation effects. Furthermore, since a larger amount must be sprayed to achieve the same effect, economic efficiency and operational efficiency may decrease.

[0035] While the aforementioned components can perform their respective functions individually, when applied as a composite composition, they can simultaneously achieve improved combustion efficiency and reduced harmful gases through synergistic effects. For example, the combination of sorbitol and CeO2 strongly reduces NOx by combining a reducing atmosphere with an oxidation catalytic reaction, while the combination of Na2CO3 and PLA simultaneously induces slag fluidity and dust aggregation at high temperatures. Furthermore, the oxidizing power of CeO2 and the adhesiveness of PLA assist in dust capture.

[0037] The method for preparing a composition having the components described above is as follows. First, purified water corresponding to 70 to 75 weight percent of the total composition is introduced into a stainless steel stirring tank, and low-speed stirring is started at approximately 300 to 500 rpm. Sodium carbonate, a water-soluble inorganic material, is slowly dispersed and dissolved in the mixture. Stirring is continued until complete dissolution occurs, and maintaining the temperature at room temperature (20 to 25°C) is suitable. Then, sorbitol (70% liquid phase), a PLA aqueous dispersion, and potassium sorbate, which are organic compounds, are added sequentially. Since PLA increases viscosity, it is desirable to add it slowly and temporarily increase the stirring speed to approximately 500 to 700 rpm to induce uniform dispersion. Cerium oxide in the form of fine particles is pre-mixed with a small amount of purified water to form a slurry, and then slowly injected into the mixture being stirred to prevent aggregation. At this stage, using a high-speed stirrer or an ultrasonic disperser is more effective. After the entire composition is completed, the final pH (approx. 8.5) and viscosity (at the level of 300–500 cP) are checked, and the remaining amount of purified water is added to make the total total 100 wt% to correct the final concentration. The final composition is filtered through a 100–200 μm filter to remove impurities, and is stored in a stirred tank or mobile storage tank to prevent solid sedimentation.

[0039] In order to verify the effectiveness of the combustion improver according to the present invention manufactured as described above, comparative effect experiments by component, NOx reduction rate experiments according to changes in composition ratio, and comprehensive performance experiments according to changes in composition ratio were conducted as follows.

[0041] [Example]

[0042] A composition with a total weight of 1,000g was prepared by mixing 785g of purified water, 120g of sodium carbonate, 70g of sorbitol (70% liquid), 3g of cerium oxide, 15g of PLA aqueous dispersion, and 7g of potassium sorbate. The viscosity was measured to be 410cp and the pH to be 8.8.

[0044] [Comparison Experiment of Effects by Ingredient]

[0045] To verify the functional contribution of cerium oxide (CeO2) and polylactic acid (PLA), which are the main components of the combustion improvement agent composition according to the present invention, a comparative removal experiment was performed for each component. To this end, NOx, CO, and dust emissions were measured by applying a composition excluding cerium oxide (Comparison Group 1), a composition excluding PLA (Comparison Group 2), and a composition according to the present invention (Example) to an incineration test environment under identical conditions, respectively, and the results are as follows.

[0046] Results of the experiment comparing the effects of each ingredient experimental group Composition NOx (ppm) CO (ppm) Dust (mg / Sm³) note Comparison group 1 CeO₂ not added in the embodiments of the present invention 27.2 6.4 - Purpose of comparing NOx and CO reduction effects Comparison group 2 In the embodiments of the present invention, PLA is not added - - 0.87 Purpose of comparing dust suppression functions The present invention Examples Examples of the present invention including all components 20.1 4.3 0.62 Confirmation of simultaneous reduction of harmful gases and dust

[0048] First, when a composition not containing cerium oxide (Comparison Group 1) was applied, the NOx concentration was 27.2 ppm and the CO concentration was 6.4 ppm. This suggests that the reduction effect of harmful gases is insufficient because the reduction atmosphere composition or the catalytic redox cycle action is limited. On the other hand, the composition excluding PLA (Comparison Group 2) showed a dust concentration of 0.87 mg / Sm³, which is interpreted as a result of dust not being sufficiently captured within the incinerator and instead being scattered due to weak dust aggregation or adhesion functions. In contrast, when the combustion improvement agent composition of the present invention was applied, the NOx concentration was 20.1 ppm, the CO concentration was 4.3 ppm, and the dust concentration was 0.62 mg / Sm³, showing a significant reduction in harmful gases and dust across all indicators compared to the comparison groups. This implies that cerium oxide induces selective redox reactions of NOx and CO, while PLA effectively performs the function of suppressing re-entrainment through the aggregation and adhesion of dust. These experimental results demonstrate that the individual components within the composition perform their respective functions while simultaneously playing complementary roles to enhance the overall performance of the composition, suggesting that the optimal formulation of multi-functional compositions can make a decisive contribution to combustion efficiency and environmental pollution reduction.

[0050] [Experiment on NOx Reduction Rate According to Changes in Composition Ratio]

[0051] Meanwhile, to determine the effect of changes in the content of cerium oxide (CeO2) in the combustion improver composition on NOx reduction performance, NOx concentrations were measured under the same experimental conditions by varying the cerium oxide content to 0.0, 0.3, 0.8, and 1.5 wt%, respectively. The measurement results are as follows.

[0052] Experimental results of NOx reduction rate according to changes in cerium oxide composition ratio Cerium oxide (%) NOx (ppm) 0.0 27.5 0.3 22.8 0.8 20.5 1.5 19.3

[0054] Experimental results confirmed a gradual decrease in NOx concentration compared to the absence of cerium oxide (NOx 27.5 ppm), with 22.8 ppm at 0.3% addition, 20.5 ppm at 0.8%, and 19.3 ppm at 1.5%. These experimental results demonstrate that cerium oxide acts as a redox catalyst that effectively decomposes or converts NOx in a reducing combustion atmosphere. In particular, the effect becomes visible starting from the addition of 0.3%, and at 1.5%, the NOx concentration decreases by nearly 30%, thereby proving the existence of critical lower and upper limits at which a substantial reduction function is achieved.

[0056] [Comprehensive Performance Experiment Based on Changes in Composition Ratio]

[0057] The effects of the combined blending ratio of cerium oxide, sorbitol, and sodium carbonate (Na2CO3) on the overall performance indicators of the combustion process—namely, NOx reduction rate, clinker area reduction rate, and combustion temperature deviation—were analyzed, and the results are as follows.

[0058] Comprehensive performance test results based on cerium oxide / sorbitol / sodium carbonate composition Cerium oxide / sorbitol / Na 2 CO 3 wt% NOx Reduction (%) Clinker Area Reduction (%) Combustion temperature deviation (±℃) 0 / 0 / 0 No criteria No criteria ±47℃ 0.3 / 5 / 10 About 17% down About 18% down ±38℃ 0.8 / 7 / 12 About 24% ↓ About 26% ↓ ±27℃ 1.5 / 10 / 15 About 29% ↓ About 34% ↓ ±15℃

[0060] Experimental results showed that the control group (0 / 0 / 0) exhibited no NOx reduction rate or clinker inhibition effect, and the combustion temperature deviation was very unstable at ±47℃. In contrast, performance improved with increasing additive amounts in the experimental group with a composite blend of components. In particular, the 1.5 / 10 / 15 composition demonstrated excellent results, with a NOx reduction rate of approximately 29%, a clinker area reduction rate of approximately 34%, and a combustion temperature deviation of ±15℃. This implies that not only do each component perform specific functions individually, but they also exhibit synergistic effects through interaction, such as improved combustion stability, slag inhibition, and exothermic characteristics. Specifically, the combined use of cerium oxide and sorbitol plays a key role in NOx and temperature stability, while sodium carbonate contributes to the neutralization of acidic gases and the promotion of slag fluidization.

[0062] Meanwhile, the present invention can maximize combustion efficiency by automatically controlling the composition and injection amount of the chemical according to the real-time combustion conditions of a waste incinerator through a controlled combustion improvement agent injection system. More specifically, the method for improving combustion efficiency according to the present invention consists of the following steps.

[0064] First, a combustion improver made of the composition of the present invention is stored in a combustion improver chemical tank (10). The said chemical is transferred to a combustion improver main supply stirring tank (20) and maintained in a uniform state through continuous stirring. At the same time, an additive for increasing calorific value, such as glycerin or a high-concentration aqueous solution of sorbitol, is stored in a separate calorific value increasing chemical storage stirring tank (30).

[0066] The TMS interlocking control unit (40) measures the real-time temperature through a temperature sensor (1) installed at a key location in the incinerator and calculates the difference from a preset reference temperature. If this temperature difference is 50°C or less, the control logic causes only the composition of the combustion improver main supply stirring tank (20) to be sprayed onto the waste through the combustion improver spraying facility (50) and a nozzle installed on the incinerator hopper or conveyor belt. On the other hand, if the temperature difference exceeds 50°C, the TMS interlocking control unit (40) extracts a certain amount of additive from the calorific value enhancement chemical storage stirring tank (30), transfers it to the main supply stirring tank (20), and after stirring for a certain period of time, controls the combustion improver spraying facility (50) to spray the mixed composition onto the incinerator (100). When the temperature difference is 50°C or less, the combustion state is relatively stable, so it is sufficient to have an effect even if only the basic combustion improver is injected. If the temperature difference is 50℃ or more, it means that combustion is incomplete or there is insufficient heat generation. In this case, it is necessary to add a high-heat component (e.g., glycerin, high concentration sorbitol, etc.) to quickly normalize combustion.

[0068] This process is fully automated, eliminating the need for real-time human intervention, and the type and amount of the composition are dynamically determined based on the combustion conditions of the incinerator. This system enhances combustion stability by immediately supplementing with exothermic additives in the event of a rapid drop in combustion temperature, while simultaneously maximizing energy efficiency by preventing excessive oxidation or heat loss caused by high temperatures. Furthermore, quantitative control of the injection volume prevents chemical waste and reduces environmental emissions.

[0070] Specific embodiments of the present invention have been described above. However, those skilled in the art will understand that the spirit and scope of the present invention are not limited to these specific embodiments, but that various modifications and variations are possible within the scope of the invention without altering the essence of the invention. Accordingly, the embodiments described above are provided to fully inform those skilled in the art of the scope of the invention and should be understood as illustrative in all respects and not restrictive, and the present invention is defined only by the scope of the claims. Explanation of the symbols

[0071] 10: Combustion improver chemical tank 20: Combustion improver main supply stirring tank 30: Calorific value enhancing drug storage stirring tank 40 : TMS Interlocking Control Unit 50: Combustion improver injection equipment 100 : Incinerator

Claims

Claim 1 delete Claim 2 A method for improving combustion efficiency in an incinerator, characterized by (a) transferring a combustion improver containing purified water, sodium carbonate, sorbitol, cerium oxide, polylactic acid, and potassium sorbate from a combustion improver storage tank to a main supply stirring tank, (b) storing a calorific value enhancing additive in a separate storage stirring tank, (c) comparing real-time temperature data of the incinerator with a reference temperature and, if the temperature difference is 50℃ or less, injecting only the combustion improver, and (d) if the temperature difference exceeds 50℃, introducing the calorific value enhancing additive into the main supply stirring tank, stirring for a certain period of time, and then injecting the mixture. Claim 3 delete Claim 4 A method for improving combustion efficiency of an incinerator according to claim 2, characterized in that the calorific value enhancing additive comprises an aqueous solution of glycerin or sorbitol.

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