KR100317999B1 - Oxygen Enriched Waste Incinerator and Incineration Method - Google Patents

Abstract

The present invention relates to an oxygen-enriched waste incineration apparatus and an incineration method, by mixing a portion of carbon dioxide gas having a purity of 98% or more generated after combustion with pure oxygen in an appropriate ratio, the oxygen concentration of 30 to 80% according to the characteristics of the waste The enriched gases are melted and discharged from the primary combustion at high temperatures (above 1,200 ℃), the organic materials are partially combusted and pyrolyzed and completely burned in the secondary combustion. After the purification process of the device, acid gas (SOx, HCl, etc.) removal device, dust removal device, etc., some carbon dioxide gas, which is the only gas remaining, is circulated to the first and second combustion furnaces, mixed with oxygen, and burned in the combustion furnace. It is used as a solvent gas, and some of it is recycled as raw materials for manufacturing liquid carbonic acid, solid carbonic acid (Dry Ice), urea fertilizer, etc., and the final ying carbon dioxide is all absorbed by alkaline aqueous solution (mainly Ca (OH) _2). Pollution-free Conversion to carbonate in the body (mainly limestone (CaCO _3)), release, or ever recycled as raw material for cement or the like, characterized by completely removing the combustion gases that cause secondary pollution.

Description

Oxygen Enriched Waste Incinerator and Incineration Method

The present invention relates to a waste incineration apparatus and an incineration method that can safely and completely burn waste by supplying pure oxygen with carbon dioxide gas at an appropriate ratio.

In general, combustible materials are more easily burned in gas with higher oxygen concentration than in air with 21% oxygen concentration, and the temperature of the combustion gas rises, resulting in more complete combustion in air. However, if the oxygen concentration is too high, the combustion speed may explode and there is a risk of an accident.

On the other hand, in the conventional incinerator for incineration of waste, the combustion gas is discharged to the atmosphere by removing the statutory allowance, and the combustion residue is solidified by landfilling. However, such combustion gas emissions and reclamation of landfills are not only pointed out as secondary pollutants, but are also becoming socially problematic.

The present invention is to recycle the inorganic material in the waste by oxygen enrichment using a mixed gas of pure oxygen and carbonic acid gas as combustion gas instead of the combustion air used in the conventional incinerator to melt and recycle at 1200 ℃ or more, Organic materials purify the combustion gas generated after the 1st and 2nd combustion, and recycle the remaining 98% of the carbon dioxide as much as possible first, and convert the surplus carbon dioxide into solid limestone or carbonate and utilize it as cement, slaked lime, etc. It aims to provide an economical incinerator that eliminates the chimneys that are the targets of air pollution and civil complaints and at the same time blocks the discharge of global warming materials by realizing the chimney-free incinerators that emit into nature as pollution-free.

1 is the overall structure and process of the waste incineration apparatus according to the present invention,

2 is a detailed structural diagram of a primary melt-pyrolysis incinerator according to the present invention;

3 is an explanatory diagram of a utilization system of carbon dioxide gas produced in an incinerator of the present invention.

※ Explanation of code for main part of drawing

1: reservoir 2: preprocessor

3: deodorizer 4: primary incinerator

5: melt processor 6: secondary incinerator

7: liquid oxygen storage tank 8: boiler

9: acid gas remover 10: dust collector

11: adsorption tower 12: carbon dioxide gas storage tank

13 carbon dioxide gas solidifier 14 water purifier

15: adsorption tower 21: feeder

22: incinerator body 23: drying rack

24: low temperature pyrolysis zone 25: combustion zone

26 melt zone 27 melt outlet

28 upper outlet 31 pressurizer

32: dehumidifier 33: adsorption purifier

34 condenser 35 liquid carbonic acid reservoir

36: solid carbonate manufacturer 37: heat exchanger

1 shows an incineration apparatus of the present invention, which is composed of a pretreatment unit (A), a melt-complete combustion unit (B), and a post-treatment unit (C).

Waste pretreatment process (pretreatment unit);

The pretreatment unit (A) is composed of a waste storage tank (1), a pretreatment unit (2), and accessories such as a deodorizer (3) and a seal.

The waste storage tank (1) mixes and stores the incoming waste and waste activated carbon generated in this process and a small amount of limestone, and the pretreatment (2) functions to partially crush the waste and supply it to the next process. . The reason for injecting a small amount of limestone into the waste storage tank 1 is to convert and remove the sulfur component contained in the waste into some gypsum and to control the melting point of the melt discharged from the lower part of the combustion section 4.

The pretreatment unit 2 is a deodorizer such as an adsorption tower filled with an adsorbent (mainly activated carbon) by injecting an appropriate amount of carbon dioxide gas so that no air is introduced into the next process, blowing out the air introduced with the waste and the odor generated. 3) The adsorbed and desorbed in 3), and the saturated adsorbent is deodorized with warm carbonic acid gas for regeneration, and the gas deodorized during regeneration is sent to the incinerator described later for combustion.

On the other hand, the leachate flowing out of the pretreatment process is filtered, the filtrate is spray-burned in the incinerator hot part, and the filter medium is mixed with the waste.

Incineration process (melt-to-burn);

The melt-complete combustion section B is composed of a primary incinerator 4 and a secondary incinerator 6, the primary incinerator 4 being the core device of the present invention and its structure is shown in detail in FIG. .

As shown, in the upper part of the primary incinerator 4, the pretreated waste is supplied by the feeder 21, and in the lower part, the combustion oxygen-carbon gas mixture gas mixed at an appropriate ratio is blown in. The waste introduced into the primary incinerator (4) is dried, vaporized, pyrolyzed, partially combusted, melted, etc. from the top, and the solids flow downwardly and are mostly converted to gas and flow upwards. Incombustible inorganics and metals are melt discharged at the bottom.

Another feature of the present invention is to use a mixed gas of oxygen-carbonate gas instead of combustion air, which can easily adjust the oxygen concentration according to the characteristics of the waste, so that the combustion conditions are always safe and stable under optimum conditions. It can maintain and eliminate the risk of high concentration of oxygen, and since there is no nitrogen inflow, the production of nitrogen oxide, a pollutant, is blocked at the source during combustion, and the purity of carbon dioxide gas, the final residue after combustion, is over 98%. It is possible to maintain and very useful for its utilization, thereby improving the economics of the process according to the present invention.

On the other hand, the pretreated waste is supplied to the upper portion of the primary incinerator 4 by the feeder 21, and the waste is dried from the top 23, the low temperature pyrolysis zone 24, the partial combustion zone 25, and the melting zone. Down through (26), all organics are partially oxidized and vaporized-low temperature pyrolyzed and sent to the secondary incinerator (5) via the upper outlet (28) at a temperature of around 500-600 ° C., with all minerals and metals at the bottom. It melts at a high temperature of 1500-1800 ° C. and is discharged from the melt outlet 27 and sent to the melt processor 5, and the inorganic material is vitrified and used as pollution-free aggregates, and metals are used as raw materials for smelters.

In order to adjust the molten state to the optimum conditions in the melting zone 26, a small amount of fuel may be injected as needed, or a small amount of solid fuel such as coke may be added at the time of waste injection. However, if there is little inorganic content in the waste or there is no need for melting, the temperature of the melting zone 26 may be lowered to about 1000 ° C., and a small amount of non-combustible solids removal device may be easily replaced.

On the other hand, the low-temperature pyrolysis gas discharged from the upper part of the primary incinerator 4 is completely burned at a high temperature by supplying oxygen-carbon gas mixed in an appropriate ratio in the secondary incinerator 6, and the mixing ratio of oxygen-carbon gas is incinerator. The temperature of combustion is automatically adjusted to at least 1200 ℃ and the residual oxygen concentration after combustion does not exceed 2%.

Oxygen required for the first and second incinerators (4) and (6) is supplied as liquid oxygen from a large number of air liquefaction plants, stored in the storage tank (7), and vaporized as necessary, and supplied at an appropriate pressure at room temperature. In this case, the cold heat generated during vaporization of the liquid oxygen is usefully used as the cold heat required when preparing the liquid carbonic acid, as shown in FIG.

Post-treatment process (post-treatment section);

The after-treatment unit C is first cooled to 1000 ° C. or less in a quenching device (not shown), which firstly sprays high temperature combustion gas discharged from the secondary incinerator 6 and then sprays the process water, and then steam in the associated boiler 8. Is produced and cooled to about 200 ° C to remove most of the acid gases (SOx, HCl, etc.) by slaked sludge in the semi-dry acid gas (SOx, HCl, etc.) remover (9), and remove the solids in the dust collector (10) Next, a small amount of impurities are adsorbed and removed from the adsorption tower 11 filled with activated carbon by cooling to room temperature, and stored in the carbon dioxide storage tank 12.

Water vapor produced in the boiler 8 is utilized for internal or external heat sources, or for power generation, and the solid matter collected in the dust collector 10 is returned to the waste storage tank 1 to be treated together with the waste, and the dust collector ( The combustion gas passed through 10) is adsorbed / removed from the adsorption tower 11, and the adsorbent is periodically regenerated and used as warm carbonic acid gas.

The gas containing impurities generated during regeneration of the adsorbent is returned to the first and second incinerators 4 and 6 for combustion with circulating carbon dioxide, and the waste activated carbon is returned to the waste storage tank 1 for combustion.

The condensate generated during the cooling process is separated and neutralized and precipitated by chemical treatment, micro-filtration, ultra-filtration, ultra-filtration, and reverse osmosis treatment according to the water quality and use in the water purifier 14. After the necessary process among purification methods such as ion exchange resin treatment, it is used for necessary purposes such as boiler water, cooling water, household water, and the surplus is drained.

The system using the carbon dioxide gas generated in the incinerator of the present invention described above is shown in FIG. 3, which is used as a raw material for urea fertilizers and various carbonates, and also uses vaporizing cold heat of liquid oxygen. It is to be used in the following ways, such as liquid carbonic acid, solid carbonic acid, refrigeration and refrigerator, district cooling.

The application fields of carbon dioxide are divided into the following.

Preparation of liquid carbonic acid;

Liquid carbonic acid is a raw material for solid carbonic acid (Dry Ice), and is widely used for welding inert gas, fire extinguisher, beverage addition, plant growth promotion, etc. In Korea, there is a demand of 20-300,000 tons per year. Conventional manufacturing methods produce carbon dioxide with a purity of 98% or more generated as a by-product from petrochemical plants and ammonia plants at about 25 atm, and then cooled and condensed to -25 ° C by an ammonia freezer. The required power is about 200kw. However, in the present invention, since the cold heat generated in the process of vaporizing the liquid oxygen required in the present process can be used, the pressurizer 31 is pressurized to a low pressure of about 6 atm, and then a dehumidifier 32 for preventing freezing of water. After the adsorption purifier 33 for high purification, the condenser 34 is liquefied using the latent heat of evaporation of liquid oxygen and stored in the liquid carbon dioxide storage tank 35, and then shipped according to the required use. In this process, the amount of liquid oxygen evaporated per ton of liquid carbonate is about 1.2 tons, and the power is about 60 kw, which is about one third of the power required in the existing general manufacturing process. When such inexpensive liquid carbonate is produced, its demand is expected to be widely used in addition to the existing demand.

Preparation of Solid Carbonate

Solid carbonic acid is a -78 ° C. forming solids produced by molding liquid carbonic acid crystal grains produced by injecting liquid carbonic acid at a high pressure in a closed solid carbonic acid manufacturing machine at a high pressure. Widely used. The amount of solid carbonic acid per ton of liquid carbonate is about 0.5 ton, and the vaporized carbon dioxide is recovered and circulated to the suction port of the pressurizer 31. The production of solid carbonic acid is applied as it is, but the production cost of liquid carbonic acid as a raw material is cheaper, so it is possible to produce and supply at a lower price than the existing solid carbonic acid.

Large-scale cold heat production

In the carbon dioxide gas utilization system according to the present invention, the power required to produce one ton of liquid carbonate is about 60 kW, and the cold heat of -40 ° C. which is obtained when evaporating one ton of liquid carbonate is about 80,000 kcal, and the cold heat of 0 ° C. It is 90,000 kcal, which means that at 1 kW of power, about 1,330 kcal of -40 ° C of cold heat and 1,500 kcal of heat of 0 ° C can be obtained, which is equivalent to the power required to produce cold heat by the conventional method, It can be used as a cold heat storage means using the midnight power, it can be advantageous to obtain a low temperature up to -40 ℃, and can be widely used in large freezers, refrigerators, refrigeration and cooling industry, regional cooling.

Preparation of Urea Fertilizer

Urea fertilizer is a representative fertilizer of neutral nitrogen produced by ammonia and carbon dioxide gas, and the required amount of carbon dioxide gas per ton is about 0.8 tons, and in Korea, it has a production capacity of 1 million tons per year. It produces urea fertilizer by making ammonia with hydrogen produced and synthesizing with by-product carbon dioxide. However, it is much more economical to import ammonia made from natural gas directly from oil producing countries than to import naphtha to produce ammonia. In this case, ammonia imported at low prices can produce cheap urea fertilizers if only a large source of carbon dioxide is supplied. As a result, it is an optimal application field for mass demand of inexpensive carbon dioxide produced in the present invention. However, due to the transportation of carbon dioxide, the place of production and the urea fertilizer plant are limited to be in the adjacent area.

On the other hand, the surplus carbon dioxide remaining and utilized to the maximum in the above manner is absorbed and solidified by an aqueous alkali solution (mainly hydrated lime) in the solidifier 13 of FIG. 1 to be solidified by carbonate (limestone, soda ash, etc.) to be released or recycled. do. At this time, excess oxygen which is a non-condensable gas contained in carbon dioxide gas, trace amount of nitrogen gas, etc. is returned to incinerator 4,6. If non-combustible gas such as nitrogen accumulates in the non-condensable gas, it intermittently passes through the small adsorption tower 15 to adsorb and remove the trace amount of impurity gas accompanying the nitrogen gas to the atmosphere.

On the other hand, in order to reduce the initial investment cost, the carbon dioxide gasifier 13 may be omitted and surplus carbon dioxide may be discharged to the atmosphere as it is, and in this case, the amount of gas emitted is less than 1/10 of the existing incinerator. It is very small and does not contain nitrogen gas, so it does not contain nitrogen oxide, which is a pollutant.It is a gas that is completely burned / refined at a high temperature of at least 1200 ℃, so it has negligible content of harmful substances such as dioxins and carbon monoxide. In addition, the amount of fine dust is significantly less than 1/10 of the existing incinerator in proportion to the emission amount, and there is an advantage that it is possible to add a carbon dioxide utilization facility and a solidification device at any time.

Hereinafter, three typical waste samples are compared with the characteristics of the case where the incinerator of the present invention is applied and the case where the conventional incineration method is applied.

Physical properties of the waste sample; (Composition:% by weight)

Sample-A;

Furtherance ; 45% organic matter (carbon fraction; 34.5%. Hydrogen fraction; 7.9%; oxygen fraction; 57.6%).

Moisture 45%,

10% minerals (metals, inorganics)

Low calorific value; 1030 kcal / kg

Sample-B;

Furtherance ; 45% organic matter (carbon fraction; 55.7%; hydrogen fraction; 3.1%; oxygen fraction; 41.2%).

Moisture 45%,

10% minerals (metals, inorganics)

Low calorific value; 1880 kcal / kg

Sample-C;

Furtherance ; 95% organic matter (carbon content; 89.6%. Hydrogen content; 3.7%, oxygen content: 6.6%).

Moisture 5%,

Low calorific value; 6530 kcal / kg

Combustion conditions

Incineration method of the present invention;

(1) The combustion temperature is to be at least 1200 ℃.

(2) The oxygen concentration in the gas for combustion is in the range of 30-80 vol%.

(3) The concentration of residual oxygen after combustion is 2 vol%.

(4) The recovery heat of combustion is 90% of the sensible heat from the combustion temperature to 200 ℃.

Conventional incineration methods;

(1) The combustion temperature is to be at least 800 ℃.

(2) Combustion gas shall be air (oxygen concentration: 21 vol.%).

(3) The residual oxygen concentration after combustion is 10 vol.%.

(4) The recovery heat of combustion is 90% of the sensible heat from the combustion temperature to 200 ℃.

(5) Auxiliary fuels shall be heavy oil with a low calorific value of 10,000 kcal / kg, necessary to raise to 800 ° C when the combustion temperature is below 800 ° C.

Sample-A

Sample-B

Sample-C

As in the above calculation results, the present invention has the following features.

First, the final gas flow rate after the complete combustion in the first and second combustion furnace of the present invention is significantly reduced to 1 / 8.1 to 1 / 13.5 compared to the flow rate compared to the conventional combustion furnace, thereby recycling the carbon dioxide gas discharged accordingly If you do not do so, you can reduce the impact on the environment. Furthermore, in the present invention, it is possible to re-resource all the gases and melts generated from the combustion water, thereby providing a chimney-free zero-emission waste treatment apparatus.

Second, as the flow rate of the combustion gas discharged from the first and second combustion furnaces is drastically reduced, the size of the unit can be reduced, resulting in a reduction in construction cost and required site.

Third, the additional cost of supplying oxygen can be sufficiently offset by considering the social cost savings of carbon dioxide recycling and waste disposal.

As described above, the present invention is capable of completely melting discharge (inorganic matter) and complete combustion (organic matter) of the waste by oxygen enrichment, and since the exhaust gas is only carbon dioxide, it can be recycled, and residual carbonic acid after the first recycling The gas can be converted into absorbed limestone with slaked lime and recycled to raw materials such as cement, and even if released into the atmosphere, the amount is only about 1/10 to 1/20 of the existing incinerator. There is no inflow of nitrogen oxides, and since the amount of exhaust gas after combustion is reduced, the equipment cost and operation cost for the treatment process are greatly reduced. In addition, the present invention, compared to the existing incinerator, the additional cost of oxygen supply, limestone cost required to solidify carbon dioxide gas is sufficiently compensated by the sale price of cheap liquid carbonate, and can eliminate the chimney that has been the target of civil complaints Social costs such as compensation for damage and waste of administrative power are fundamentally eliminated, and the carbon dioxide emissions can be greatly reduced or blocked, which has the effect of preventing global warming and the enormous international ripple effect.

Claims (4)

A pretreatment unit (A) consisting of a waste storage tank (1) for mixing and storing imported waste and activated activated carbon and a small amount of limestone, a pretreatment unit (2) and a deodorizer (3) for partially crushing the waste and supplying it to the next process; A primary incinerator (4) and a secondary incinerator (6), the pretreated waste being fed to the top of the primary incinerator (4) by a feeder (21) and the waste from the top, drying rack (23), low temperature pyrolysis. While going down the stage 24, the partial combustion zone 25, and the melting zone 26, all the organic matter is partially oxidized and pyrolyzed to pass through the upper inlet 28 at the temperature of about 500-600 ° C. 6), all inorganics and metals are melted at a high temperature of 1500-1800 ° C. at the bottom, discharged from the melt outlet 27 and sent to the melt processor 5, and discharged from the upper part of the primary incinerator 4. The pyrolysis gas is a melting-complete combustion unit (B) for completely burning at high temperature by supplying an oxygen-carbonate gas mixed at an appropriate ratio in the secondary incinerator (6); And After cooling the high-temperature combustion gas discharged from the secondary incinerator 6 to 1000 ° C. or less in a quenching device, water vapor is produced in the associated boiler 8 and cooled around 200 ° C., and the semi-dry acid gas (SOx, HCl, etc.) Removed most of the acid gases (SOx, HCl, etc.) by the slaked sludge from the remover (9), removed the solids from the dust collector (10), and then cooled to room temperature in a adsorption tower (11) filled with activated carbon. Waste incineration device, characterized in that consisting of after-treatment (C) to adsorb and remove impurities in the carbon dioxide storage tank (12). Iii) A portion of carbon dioxide gas with purity of 98% or higher generated after combustion in pure oxygen is mixed at an appropriate ratio, Ii combusting the waste at 1,200 ° C. or higher with a gas enriched in the oxygen concentration of the oxygen / carbon gas mixture gas of step iii) in the range of 30 to 80 vol% according to the characteristics of the waste; Iii) purifying the gas produced after combustion through a heat recovery device, an acid gas (SOx, HCl, etc.) removal device, a vibration damper; Iii) circulating, mixing with oxygen, and using combustion gas of the combustion furnace as a whole or part of carbon dioxide gas which is the only gas generated after the step iii); And v) converting the final residual carbonic acid gas which is not used in the step iii) into an aqueous alkali solution and converting it into a solid carbonate which is a pollution-free waste. Iii) A portion of carbon dioxide gas with purity of 98% or higher generated after combustion in pure oxygen is mixed at an appropriate ratio, Ii combusting the waste at 1,200 ° C. or higher with a gas enriched in the oxygen concentration of the oxygen / carbon gas mixture gas of step iii) in the range of 30 to 80 vol% according to the characteristics of the waste; Iii) purifying the gas produced after combustion through a heat recovery device, an acid gas (SOx, HCl, etc.) removal device, a vibration damper; Iii) using all or part of the carbon dioxide gas which is the only gas generated after the step iii) as a raw material for producing liquid carbonic acid, solid carbonic acid (dry ice), urea fertilizer and carbonate; And v) converting the final residual carbonic acid gas which is not used in the step iii) into an aqueous alkali solution and converting it into a solid carbonate which is a pollution-free waste. Iii) A portion of carbon dioxide gas with purity of 98% or higher generated after combustion in pure oxygen is mixed at an appropriate ratio, Ii combusting the waste at 1,200 ° C. or higher with a gas enriched in the oxygen concentration of the oxygen / carbon gas mixture gas of step iii) in the range of 30 to 80 vol% according to the characteristics of the waste; Iii) purifying the gas produced after combustion through a heat recovery device, an acid gas (SOx, HCl, etc.) removal device, a vibration damper; Iv) liquid carbonation of all or part of carbon dioxide gas, which is the only gas generated after the above step iv), using midnight electric power, and used it as a large freezer, refrigerator, freezing and cooling industry, and cold storage means for district cooling Making; And v) converting the final residual carbonic acid gas which is not used in the step iii) into an aqueous alkali solution and converting it into a solid carbonate which is a pollution-free waste.