KR20140107827A - Improvement Technology of Stoker type Municipal Solid Waste Incineration Facility using Low-Temperature Vitrification Process - Google Patents

Abstract

The conduction method of the present invention, as a process technology of heating and melting ash generated after burning city waste under a relatively low temperature of 1,200-1,400°C and forming a mineral component within the ash into a glassy melted substance, is a method of uniformly mixing the ash and broken glass pieces of glass waste in order to reduce a melting temperature of the ash. The method comprises mixing about 10-50 parts by weight of broken glass pieces of the glass waste in 90-50 parts by weight of the ash and melting the same, wherein the heating condition includes heating and melting the same from room temperature to 1,400°C at a constant heating rate; maintaining the same at 1,400°C for an hour; cooling the same in a furnace; and rapidly cooling the same at 600°C or lower.

Description

TECHNICAL FIELD [0001] The present invention relates to a stoker type waste incineration facility having a low-temperature melting vitrification process,

The present invention relates to a process improvement method for a stocker type waste incineration facility employing a low-temperature melting and vitrification process, more preferably a process for improving the process of melting all the incineration ash discharged from a conventional stoker type incinerator at a relatively low temperature, It is intended to suggest a technical solution to effectively solve environmental weaknesses found to be relatively vulnerable to food waste incineration facilities.

In the treatment of municipal waste in the past, it was easy to simply return to nature using open burning or landfill, and the circulation system that recycled resources was balanced in its own way. However, since the advent of the industrialization period, the amount of municipal waste generated has increased explosively by the early 2000s due to population growth, mass production and mass consumption. As a result, In 1984, a large-scale incineration facility for waste was constructed, and a stoker-type continuous incineration facility of 50 tons / day was installed in Uijeongbu City. However, this incinerator failed due to lack of analysis and incineration techniques for the waste materials in Korea and lack of ability to deal with the garbage in the country of Japan TAKAKAMASA. Then, as part of the intensive heating in the Mokdong area of Seoul, the incineration facility of 150 tons / day, which is the first facility to incorporate energy by waste heat recovery, ie, the concept of waste-to-energy, has been successfully completed. In 1986, OECF funded construction of a 200 ton / day stoker-type incinerator in Daegu and a 100-ton / day fluidized-bed incinerator in Seongnam city. In 1991, a 400 ton / day And 800 tons / day of recycling facilities in the Noon area. In Korea, as the basic incineration technology and operation techniques for incinerator construction have been established, the government has set up the incineration priority policy of the refuse incinerator nationwide, and the incineration facility of the direct incineration system nationwide.

This has spread to Korea, and the incineration technology and the waste gas treatment designing technology for suppressing harmful gas generation such as dioxin have been secured and satisfied the emission standards of air pollutants. At the same time, the following problems have been raised. The main problems are the recent incidence of inconveniences in the existing incinerator due to the high-caloric municipal waste, secondary pollution caused by incineration ash, and landfill shortage due to incineration ash. In addition, the international environmental regulation [CO2 (CO ₂ )] is strengthened for the exhaust gas, and the necessity of the energy technology of the incineration heat source can be enumerated (Ministry of Environment, 2011)

In Korea, as of 2010, 61 municipal solid waste incineration facilities were operated by 53 stoker type incinerators, 3 fluidized incineration incinerators and 5 pyrolytic incineration facilities, totaling 14,554 tons / Day of garbage is being incinerated (Ministry of Environment, 2012) The government plans to increase the incineration ratio to 23% by 2011, but the installation is delayed due to the difficulty of securing local costs due to the economic crisis of the IMF, the opposition of local residents to the location of treatment facilities, And the incineration ratio of municipal waste in 2010 is 21.6%. In addition, the government plans to revise the second National Waste Management Plan (2002-2011) to reduce the incineration rate from 30% to 23% by 2011, while pursuing a policy toward MBT (Mechanical Biological Pretreatment) (Ministry of Environment, 2011), it is still required to construct a new incinerator.

However, considering the experience so far, we have solved the structural and environmental problems of existing stoker-type facilities, which are currently major incinerators in Korea, and maximized the efficiency of incineration, rather than continuously adding new irrigation incinerators. It is considered that the development of effective improvement technology which can be considered as a sufficient consideration even more in the future is more urgent. In other words, there is a great demand for improvement of environment-friendly process for the second environmental pollution concern of incineration as it is finally discharged from existing stoker type incinerator.

As the problems and alternatives of the incineration facilities currently in operation in Korea can be seen, the development and application of technologies to reduce the environmental destruction factors caused by the atmospheric pollutants and wastewater generated in the incineration process and the domestic industrial structure centering on the stoker type incineration facilities The development and application of effective energy recovery technology for greenhouse gas, incineration heat, and the most environmentally important stabilization and recycling of ash are considered to be urgently needed in the incineration industry in Korea. However, even if it is an environmentally important issue, the unconditional development and application of the technology without economical advantage is ineffective. Therefore, it is possible to harmonize the relatively good economical efficiency of the stoker type incineration facility and the absolute environment friendliness of the pyrolysis melting facility It is believed that the feasibility will be high if concrete technical solutions are provided.

Therefore, in order to minimize secondary environmental pollution caused by incineration and to establish a "sustainable resource recycling-based economic society foundation", which is the vision of the second national waste comprehensive plan, The present invention has a fundamental purpose of providing a practical and concrete process improvement method which is complemented.

Another object of the present invention is to provide an incineration method and a process improvement method that are most appropriate for existing municipal waste incineration facilities in terms of technical efficiency and economy.

In order to accomplish the above object, the present invention provides a method for improving the process of a conventional stoker-type waste incineration facility using a low temperature melting glassification process according to the present invention.

The method for melting vitrification of an ash material according to the present invention is characterized in that the incineration as a to-be-treated substance is heated and melted at a relatively low temperature of 1,200 to 1,400 ° C due to combustion heat of fuel or thermal energy obtained from electricity by a melt solidification process, Of the melt. The melts become glassy materials composed mainly of SiO2, Al2O3 and CaO, and the molten metal rarely leaches out. The heavy metals of low boiling point contained in fly ash and the like are volatilized into the exhaust gas and then concentrated in the molten fly ash collected by the exhaust gas treatment apparatus. The heat source of melting can be roughly classified into a method by the heat of combustion of the fuel and a method by the thermal energy of electricity. The melting reduction has a reduction effect of 1/4 to 1/6 depending on the melt solidification, and the melt is largely reduced in that the true specific gravity is 2.5 to 2.7 and the melt weight is 1.6 on the basis of the unit volume weight. It is possible to concentrate low-boiling heavy metals in fly ash, but since heavy metals having a low boiling point are vaporized by gas, it is necessary to perform sufficient exhaust gas treatment. Measures are needed because the melted materials in the molten state and the alkaline salts such as Na and K are eroded seriously in the area where the melt of fly ash contacts directly. The leaching of heavy metals in the molten and solidified melt is not detected at all at low pH, and it is easy to reuse because it contains less aluminum and iron than fly ash.

According to the present invention, when the low temperature melting vitrification process is applied to improve the process of existing stoker type waste incineration facilities, the following concrete effects are expected.

1. Exhaust emissions of conventional stoker-type incineration facilities When the landfill ash itself is disposed of, it is found that there is a very serious concern about environmental pollution. Although the government currently allows landfill to be reclaimed in its original form, and only the fly ash that is highly likely to dissolve harmful components such as heavy metals is disposed of after being stabilized, the landfill is dismantled. However, In addition, direct landfilling can lead to very dangerous results. Accordingly, when the entire amount of the ash materials is melt-solidified and stabilized by addition of the low-temperature melting glassification process which can be applied even with relatively inexpensive facility investment and operating obesity as provided in the present invention, the elution phenomenon of the harmful heavy metal components contained in the ash It can be effectively controlled or prevented.

 2. On the other hand, summarizing the results of the comprehensive economic feasibility study following the addition of the molten glass vitrification process, it can be concluded that the following merits exist.

 ① It will be possible to obtain the effect of reducing / reducing the amount of final disposal waste by about 1/10 ratio compared with the case of discharging in the form of incineration ash in general stoker type incinerator, and reducing the final landfill cost The effect is expected to be significantly greater.

 (2) If the final landfill is carried out in the form of molten glass, which is not treated as incinerator, the duration of use of landfill can be significantly extended proportionally.

 ③ On the other hand, when disposing of incinerated ashes such as designated wastes or infectious wastes, it may be re-designated as general wastes from environmentally friendly characteristics that the second environmental pollution concerns may be eradicated as a result of the above- In this case, additional landfill cost savings can be expected.

* Current waste landfill cost

 -. Wastes: 40,000 ~ 50,000 won / ton

 -. Designated waste: 85,000 ~ 95,000 won / ton

 ④ In addition, depending on the type of wastes to be incinerated, there may be limitations in the law, but the results of molten vitrification of general household waste incineration as well as specific hazardous wastes are based on the environmental stability described above, (ECO Product) certification system to expand the applicability of the ECO Product certification system so as to eliminate the prejudices of general consumers about these materials and to use them safely. If the government provides institutional and policy support for market development, it will be possible to create an additional revenue structure.

Fig. 1 is an overall process diagram of an environmentally friendly low-temperature melting vitrification system for incineration ash
Fig. 2 is a detailed drawing of a melting furnace for eco-friendly low-temperature melting and vitrification of incineration ash
Figure 3 shows the results of XRD comparison analysis of ash
FIG. 4 is a graph showing a low temperature melting vitrification process
Fig. 5 shows the results of the standard dissolution test (KSLT)
FIG. 6 shows the results of the melting and vitrification of the ash materials
Figure 7 shows the results of the melting and vitrification of the ash materials.

Hereinafter, a method for manufacturing a stabilized ash slag by applying a low temperature melting glassification process to incineration ash discharged from a conventional stoker type waste incineration facility according to the present invention is as follows.

1) Sample Preparation

As a denitrification facility, two representative domestic municipal municipal waste incineration facilities applying SCR (Selective Catalytic Reduction) selective denitrification facility and SNCR (Selective Non-Catalytic Reduction) denitrification facility were selected and each site A incinerator: SCR facility, and B incinerator: SNCR facility). As a representative sample, bottom ash and fly ash were collected and used as experimental samples. The floor material of each incinerator was classified as A-1, B-1, and fly ash was classified as A-2, B-2.

The results of comparative analysis of XRD (Phillips, APD-15, 30 kV, 40 mA, scan speed 5 ° / min, Cu target) for each incineration ash sample and the chemical composition analysis (PerkinElmer, ICP-MS NexIon 300 series) Table 1 summarizes the results. XRD results show several peaks appearing in the crystalline structure, indicating that both the bottom ash and the fly ash have a large amount of crystalline inorganic material structure. However, there was a difference in the crystalline components of the bottom ash and fly ash. SiO 2 and CaSO 4 components were observed in two samples of bottom ash, whereas SiO 2 signals were weak in two samples of fly ash. It is seen that SiO2, which is the main component of sand, is contained in the bottom ash, and the component decomposed at high temperature such as CaSO4 is not contained in fly ash. These results can also be seen in the chemical composition table of Table 1.

As a result of the above analysis, samples A-1 and B-1, which are independently sampled at each site, are composed mainly of SiO 2 and Al 2 O 3, and the alkaline earth metal oxides and carbon generated in the high temperature incineration process And Cl components and various heavy metals were found to be negligible. The results of XRD analysis showed that silica (SiO2) and calcium carbonate (CaCO3) existed as the main crystal phase as commonly observed in the conventional high temperature heat treatment products.

On the other hand, samples A-2 and B-2, which are fly ash samples, contain CaO as a main component, unlike flooring, contain a large amount of Cl components, and various heavy metals are also found to be negligible. XRD analysis of fly ash showed that Ca (OH) 2 and CaF2 were the main crystalline phases. The Cl component is present in the form of NaCl and KCl, and the Cd component is present as a crystalline phase.

2) Experimental Manufacturing Method

A) Melting vitrification experiment

As an alternative to incineration facilities that require relatively low operating costs while reducing the amount of incineration ash, it is important to consider the use of colored bottle glass products that are known to be difficult to exploit for effective recycling purposes other than return to the original product process A very common glass-ceramic process technique was introduced in this experiment to mix the wave glass with the incineration ash samples in proper amounts.

In a conventional glass factory, it is necessary to lower the melting temperature of natural glass composition materials (silica, silica, limestone, etc.) to lower the productivity and energy cost of waste glass glass cullet It is used as a raw material (usually mixed with about 30 wt%). Accordingly, in the experiment of the present invention, the incineration ash and the glass wastes of the colored glass waste are uniformly mixed at a ratio of 7: 3 wt%, and the mixture is heated at a constant heating rate (10 ° C./min) at 1200 ° C., 1300 ° C., And a preliminary experiment was conducted. As a result of the preliminary experiment, the XRD analysis results showed that the crystallization phases which were not fully vitrified in all the ash samples were observed at 1200 ℃ and 1300 ℃. The optimal temperature for the vitrification process was 1,500 ^o C Which was similar to the result of the experiment.

In this case, 90 to 50 parts by weight of the ash is mixed with about 10 to 50 parts by weight of glass wastes of glass waste, and the mixture is heated and melted at a constant heating rate from room temperature to 1,400 ° C. Maintaining the temperature for a period of time, and then cooling the mixture to quench at 600 ° C or lower.

The molten vitrification specimens were heated up to 1,400 ℃ and maintained for 1 hour and then quenched below 600 ℃. The molten vitrification specimens of the flooring were A * -1 and B * -1, respectively, and the molten vitrification specimens A * -2, B * -2. FIG. 4 shows a flow chart of the present molten vitrification experiment.

B) Experiment of heavy metal release

In general, hazard assessment for solid waste is based on toxicity test by extraction method. Therefore, in a concrete experiment to confirm the effect of the present invention, the elution test was performed according to the standard leaching test (KSLT, Korea Standard Leaching Test) of the waste process test method shown in FIG.

3) Experimental results

A) Results of melting vitrification of ash

A photograph of the results of the melting vitrification of the ash is shown in FIG.

In this photograph, it is easy to see that the bottom ash and fly ash of each incinerator show vitrification characteristics of similar tendency with unique color characteristics. On the other hand, it is considered that the powder of incinerator ash is originally derived from the difference. However, there is a concern that the particle shape of the resultant molten vitrification product of fly ash is finer than that of the bottom ash and its strength is also slightly weaker than that of the bottom ash. This may have been the result of the complete absence of free amorphization and that these results could directly affect the subsequent heavy metal leaching experiments. This judgment is more clearly seen from the results of chemical composition analysis and XRD comparison analysis of the molten vitrification samples shown in Table 2 and FIG.

That is, from the XRD comparative analysis results of the molten vitrification samples shown in FIG. 7, two molten vitrification specimens of the flooring exhibit the characteristics of a gentle parabolic amorphous glass material, which is a typical diffraction curve, , It was found that the vitrification did not proceed completely in that the two molten vitrification samples of fly ash had a rather sharp parabolic curve. This suggests that a large amount of Cl components in fly ash inhibited the progress of vitrification at low temperature.

On the other hand, the analysis results of the chemical composition of the molten vitrification samples shown in Table 2 show that the content of SiO2 is higher than the incineration ash before the treatment, because Cl, S and C components are volatilized during the melting process, It is considered to be influenced by the added wave glass.

 B) Experimental results of heavy metal leaching from ash and molten vitrification

Table 4 shows the dissolution test results of 4 samples of each ashes and 4 samples of the molten vitrification test according to the experimental method described above.

Despite the high content of bottom ash, the leaching ratio of each element was low and the leaching ratio was relatively high even though the content of fly ash was small. The reason for this is that the Cl component, which has a high content in fly ash, becomes HCl in the leaching test, and the leaching ratio is higher than that of the bottom material because it directly contributes to the leaching reaction of the other components directly. Also, it is considered that the cause of the fine particles of fly ash is finer than the bottom ash.

The dissolution test results of incineration ash and molten vitrification showed that Zn, Pb, Cr, And showed a very severe elution rate characteristic far exceeding the EPA regulatory concentration. However, it was found that the molten vitrification samples of all of the incinerator samples showed very little or no detectable elution. This can be explained by the mechanism of stabilization of heavy metal components by ordinary vitrification because various heavy metal ions which are highly likely to dissolve act as a network modifier of the glass structure during the vitrification process and are collected in the silica mesh structure and exist very stable . On the other hand, due to the differences in the degree of vitrification described above, the molten vitrification samples of the fly ash were slightly larger than the molten vitrification samples of the bottom ash, but the results were also within the respective regulated concentration ranges This does not seem to be a big concern. However, considering the case of incineration of wastes with high environmental management requirements such as various designated wastes and infectious wastes, it is possible to make such a determination only in the case of the samples adopted in the present experiment. It was judged that sufficient molten vitrification treatment had to be performed at a higher temperature.

4) Experimental result synthesis

A) Among the municipal waste incineration ash, SiO2, Al2O3 and CaO were the main constituents of the bottom ash, and alkaline earth metal oxides and carbon generated during the high temperature incineration process were found to be subsidiary constituents. The results of XRD analysis showed that silica (SiO2) and calcium carbonate (CaCO3) existed as the main crystalline phase. On the other hand, the samples of fly ash consisted mainly of CaO, unlike the flooring material, contained a large amount of Cl components, and various heavy metals were found to be inevitably contained. XRD analysis showed that Ca (OH) 2 and CaF2 existed as main crystal phase, Cl component existed as NaCl and KCl, and Cd component existed as crystalline phase.

(B) For the purpose of improving the economy, the molten glassification temperature of incineration ash is lowered, and 30% of the wastewater of colored glass waste is homogeneously mixed with each ashes under a mixed purpose for effective utilization of other wastes which are difficult to recycle, As a result of vitrification, it was possible to produce a good glass melt at a relatively low temperature of 1,400 ° C.

(C) After analyzing the contents of harmful heavy metals contained in each ash sample, we compared the amount of leaching with the waste elution test method. As a result, it was found that a large amount of hazardous heavy metals were eluted to a serious level there was. On the other hand, only very small amounts were detected in the molten vitrification samples or the results were below the regulated concentration.

(D) Based on the above experimental results, it is considered that there is a serious concern about the second environmental pollution when the incineration ash of the general stokker type incineration facility is simply landfilled, It was judged that the vitrification treatment would effectively control or inhibit the dissolution phenomenon of harmful heavy metal components even at a relatively low facility investment and operation cost.

(E) The most important factor to consider when investing in these additional facilities is the deterioration of economic efficiency due to the excessive investment burden and the operational expenses. As one example of the various heat treatment melters currently being used in related industries, To provide an improvement method of an environmentally friendly low-temperature melting vitrification treatment plant as shown in Figs. 1 and 2.

Claims (3)

Wherein the incinerator incinerator is made by mixing wastewater with incinerator and heating and melting the incinerator at a low temperature to produce an inorganic component in the incinerator as an amorphous glass melt. Process improvement method. The method according to claim 1,
Characterized in that, in order to lower the melting temperature of the incineration ash to a low temperature of 1,200 to 1,400 ° C, about 90 to 50 parts by weight of the ash is mixed with about 10 to 50 parts by weight of glass raw wastes of glass product waste. Process Improvement Methods for Food Waste Incineration Facilities. The process according to claim 1, wherein the melting treatment is performed by heating and melting at a constant heating rate of from 1,400 to 1,400 at room temperature, holding at 1,400 for 1 hour and then cooling, and then quenching at 600 or less. Process improvement method of applied stoker type waste incineration facility.

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