KR101322075B1 - Apparatus for recovering energy using solid biofuel with improved acid gas treatment efficiency - Google Patents

Abstract

PURPOSE: A device recovering energy by using solid biofuel having excellent efficiency processing acid gas is provided to secure the effectiveness by minimizing the excessive use of combustion air and the generation of unburned powder caused by the heat loss and maximizing the energy recovering efficiency. CONSTITUTION: A device recovering energy by using solid biofuel having excellent efficiency processing acid gas comprises a biofuel supply unit, a traveling-stoker type incinerating boiler, an unburned powder returning conveyor, an economizer (50), an air preheater, a steam turbine generator, one or more wet electrical dust collector (80), a selective catalytic reduction top (90). The unburned powder returning conveyor circulates unburned powder generated in the incinerating boiler to a traveling-stoker (20) and improve the combustion efficiency. The wet electrical dust collectors remove the acid gas and dust generated in a combusting process. The selective catalytic reduction top additionally removes nitrogen oxide generated in the combusting process. [Reference numerals] (AA,LL) Reducing chemical storage tank; (BB) Steam; (CC) Degassifier; (DD) Boiler water supply tank; (EE) Reducer; (FF) Generator; (GG) Power production; (HH) Steam supply; (II) Selective non-catalytic reduction; (JJ) Second air blower; (KK) Combusted gas re-heater; (MM) Clamp-off air blower; (NN) Stocker re-discharge conveyor; (OO) Water supply heater; (PP) Induced air blower; (QQ) Chimney

Description

Energy recovery system using bio solid fuel with excellent acid gas treatment efficiency {APPARATUS FOR RECOVERING ENERGY USING SOLID BIOFUEL WITH IMPROVED ACID GAS TREATMENT EFFICIENCY}

The present invention relates to an energy recovery apparatus using a biosolid fuel having excellent acid gas treatment efficiency, and more particularly, unburnt that causes heat loss in the process of burning biosolid fuel including wood-based biomass through an incineration boiler. Energy recovery system using biosolid fuel with excellent acid gas treatment efficiency that can maximize the energy recovery rate by minimizing the generation of dust and the use of more than necessary combustion air and at the same time reliably and efficiently treating the high concentration of acid exhaust gas generated during combustion. It is about.

Recently, as the problem of climate change caused by global warming is a serious threat to human survival, interest in renewable energy is increasing, and investment to replace existing fossil fuels is rapidly increasing. In this reality, biomass is attracting attention as a field of alternative energy that can solve the concern about depletion of fossil fuel and environmental pollution.

Biomass is a term that refers to a bioorganism including plants, cells, and animals that eat and live by photosynthesis of plants and microorganisms that receive solar energy. Thus, biomass resources include starch-based resources such as grains, wood chips and waste woods, cellulose-based resources including rice straw, rice hulls, and saccharide-based resources such as sugar cane, sugar beet, and food wastes. It has a comprehensive meaning including everything from organic waste.

At present, there are about 1.8 to 2 trillion tons of biomass on dry weight, and about 200% of biomass is produced annually, which is about 10% of this amount, which is about 0.1% of the solar energy on earth. Percentage corresponds to the accumulation of biomass, and biomass is an attractive energy source compared to fossil fuels because it is essentially free from environmental impacts from CO ₂ .

The method of energizing biomass can be divided into thermochemical and biological methods. Among the thermochemical methods, the oldest energy conversion technology is the incineration method. The process of energy recovery of biomass through incineration is determined by process composition and unit equipment design conditions according to the characteristics of the incoming materials and the concentration of air pollutant in the downstream.Incineration is generally based on the type of incinerator. (Stoker) and Fluidized Bed incinerators.

Traveling-stalker type incineration boiler device is commercialized due to the low cost of facilities and ease of operation, but clogging phenomenon of reservoir and supply reservoir supplying biosolid fuel, treble-torker distortion caused by the incorporation of foreign substances, and fine dust generation There is a problem with low energy recovery rate.

In recent years, the allowable concentration of air pollutant emissions is more strictly managed by the regulation of total amount of air pollutants. If the fuel contains high concentrations of pollutants, the target concentration of the existing flue gas treatment system is the target concentration. There is a case that can not be achieved.

The present invention is to overcome the above-mentioned problems of the prior art, one object of the present invention is to structurally solve the clogging phenomenon of the biofuel supply storage for supplying the biosolid fuel structurally stable heat recovery in the back-end incineration boiler It is to provide an energy recovery device using a bio solid fuel.

It is another object of the present invention to provide an energy recovery apparatus using biosolid fuel having excellent acid gas treatment efficiency, which can secure economic efficiency by maximizing energy recovery by minimizing the generation of unburned dust and the use of combustion air more than necessary to cause heat loss. To provide.

It is still another object of the present invention to provide an energy recovery apparatus using biosolid fuel which can treat acid gas with high efficiency to meet strict emission standards by minimizing the emission of acid gas in recovering energy from biofuel.

One aspect of the present invention for achieving the above object is

A biofuel supply storage unit supplying the biofuel;

A treble-stocker incineration boiler which incorporates a treble-stocker for incineration of the supplied biofuel, and recovers steam by using the hot combustion gas generated in the treble-stocker;

A fine fuel conveying conveyor configured to increase combustion efficiency by circulating the fine fuel generated in the incineration boiler to the traveling-stocker;

An economizer for heating the boiler feed water supplied to the incineration boiler;

An air preheater for heating up the combustion air supplied to the incineration boiler;

A steam turbine generator for producing electricity by using steam produced in the incineration boiler;

One or more wet electrostatic precipitators connected to the incineration boiler to remove acid gases and dust generated during combustion;

It is connected to the wet electrostatic precipitator, and relates to an energy recovery apparatus using a biosolid fuel having excellent acidic gas treatment efficiency including a selective catalytic reduction tower that additionally removes nitrogen oxides generated during combustion.

According to the energy recovery apparatus of the present invention, the heat recovery rate can be increased through a configuration capable of supplying stable and continuous biosolid fuel and minimizing heat loss.

In addition, according to the present invention, even if a high concentration of contaminants in the biofuel can reduce the content of the acid gas contained in the exhaust gas, it is possible to improve the stability of the treatment compared to the conventional method, and to reduce the treatment cost.

1 is a block diagram of an energy recovery apparatus using a solid fuel having excellent acid gas treatment efficiency according to the present invention.
2A and 2B are cross-sectional views and a plan view of a solid fuel supply reservoir of an energy recovery apparatus using solid fuel having excellent acid gas treatment efficiency according to the present invention.
3 is a detailed cross-sectional view of an incineration boiler of an energy recovery apparatus using solid fuel having excellent acid gas treatment efficiency according to the present invention.
4 is a photograph and a schematic view of a cross girder traveling-stocker of an energy recovery apparatus using solid fuel having excellent acid gas treatment efficiency according to the present invention.
5 is a photograph and a schematic diagram of a conventional traveling-stocker.
Figure 6 is a schematic cross-sectional view of a wet electrostatic precipitator of the energy recovery device using a solid fuel having excellent acid gas treatment efficiency according to the present invention.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. With reference to the accompanying drawings will be described in detail a preferred embodiment of the energy recovery apparatus using a bio solid fuel excellent in acid gas treatment efficiency according to the present invention, the present invention is not limited to the following examples.

1 is a system configuration diagram of an energy recovery apparatus using a biosolid fuel having excellent acid gas treatment efficiency according to an embodiment of the present invention. The energy recovery apparatus using the biosolid fuel of the present invention includes a solid fuel supply storage unit 10 for supplying the biosolid fuel, and a treble-stalker 20 for incineration of the supplied biofuel. Traveling-stocker type incineration boiler (30) for recovering steam using combustion gas, unburned conveying conveyor (40) for circulating the unburnt generated in the incineration process to the traveling-stocker to increase combustion efficiency, incineration boiler An air preheater 60 for raising the combustion air supplied to the incineration boiler and a steam turbine generator for producing electricity using steam produced by the incineration boiler 30. (70), at least one wet electrostatic precipitator (80) for removing acidic gases and dusts from the air pollutants generated in the combustion process in the incineration boiler (30), the air pollution The quality of selective catalytic reduction including a container (90) for removing nitrogen oxides.

2A-B, the solid fuel supply storage unit 10 includes a storage tank 11 for storing biofuel; A supply chute 12 for supplying the biofuel stored in the reservoir to the traveling-stocker 20; And one or more screwed dischargers 13 driven by the drive motor 15a to transfer biofuel to the feed chute by rotation of the screw, wherein the reservoir 11 and the feed chute 12 are bio It is composed of a bottom enlarged structure that is widened in the lower direction in which fuel is discharged.

As illustrated in FIG. 2A, the storage tank 11 is used to prevent fuel entanglement (bridges) from occurring due to uneven shape of the biosolid fuel and consolidation pressed down from the top. And the supply chute 12 have a bottom enlarged structure. In addition, as shown in FIG. 2B, a plurality of screw ejectors 13a to 13c are arranged and moved up and down by driving motors 15a and 15b along rails 14a and 14b on the left and right sides of the screw ejector 13. While transferring the solid fuel to the supply chute 12 by the rotation of the screw to prevent long-term accumulation and entanglement in the reservoir (11).

3 is a detailed view of the traveling-stalker type incineration boiler. Referring to FIG. 3, the incineration boiler 30 of the energy recovery apparatus using the biosolid fuel of the present invention is a traveling-stoker type incineration boiler. As shown in FIG. 3, the biosolid fuel supplied from the biosolid fuel supply storage 10 to the traveling-stocker 20 is incinerated on the stocker rotating by the drive shaft 21a.

As shown in FIG. 5, the conventional traveling-stalker type incineration boiler 30 has a large gap in the upper horizontal plane, and thus, a large number of foreign substances are mixed, and the jamming of the foreign substances occurs, thereby causing damage to the traveling-stalker. Resulting in unstable energy recovery problems. In the present invention, in order to solve such a problem, as shown in Fig. 4, the traveling-stocker of the cross girder system 23, in which the gap of the upper horizontal plane is made fine, is used.

As such, the present invention prevents uniform heat load retention and traveling-stalker warpage of waste through the application of the cross girder method 23, and makes the same direction of supply of fuel and rotational direction of the traveling-stalker 20. By applying a forward fuel supply method to increase the combustion efficiency, it is possible to minimize the generation of carbon monoxide generated during unstable combustion.

The present invention is an incinerator structure incineration boiler structure, that is, boiler type water pipe (Water) in order to increase the heat recovery rate in the form of steam from the biosolid fuel supplied with the cross-girder travelling-stocker 20 and the forward operation. A tube type structure 31 is adopted. The general incinerator structure has a refractory structure to withstand the high temperature flue gas generated during incineration, and supplies more combustion air than necessary to maintain an appropriate flue gas temperature (850 to 900 degrees), causing heat loss. However, in the present invention, by adopting a boiler water pipe type structure, it is possible to convert the hot exhaust gas generated at the time of combustion while supplying only the required combustion air and convert the water into a steam form while recovering it with the water filled in the tube.

The heat recovery rate of the cross-girder traveling-stocker 20, the forward operation, and the boiler-type water tube type incineration boiler 30 is minimized. To this end, in the energy recovery apparatus of the present invention, fine fine powder falling to the bottom of the traveling-stocker 20 and fine powder of the lower hopper 32 at the rear end of the incineration boiler are fed back into the combustion chamber of the traveling-stocker. And 40.

The fine powder conveying conveyor (40) is a stocker conveying conveyor (41, 42, 43) for re-injecting the fine fine dust falling to the lower part of the traveling-stocker 20 into the combustion chamber of the traveling-stocker; And a boiler conveying conveyor 44 which feeds the fine powder of the lower hopper 32 at the rear end of the incineration boiler into the combustion chamber of the traveling stocker 20. The present invention can maximize the energy recovery efficiency than the existing boiler efficiency through the heat recovery rate increase method described above.

In the energy recovery apparatus of the present invention, one or more wet electrostatic precipitators 80 are connected to the traveling-stalker type incineration boiler 30 to treat acidic gas in the air pollutant generated in the combustion process with high efficiency. Referring to Figure 6, the wet electrostatic precipitator 80 can be removed at the same time by treating the acid gas and dust stably through a three-step reaction. That is, the wet electrostatic precipitator 80 includes a temperature reduction section 81 for reducing the combustion exhaust gas discharged from the incineration boiler 30; A neutralization cleaning section 82 for neutralizing the acid gas in the flue-gas exhausted by using an alkaline compound; And an electrostatic precipitating section 83 for removing residual acid gas and dust remaining in the mist.

In the first stage temperature reduction section 81, the combustion flue gas discharged from the outlet of the incineration boiler 30 is sprayed with cooling water to reduce the temperature to about 60 degrees, and in the second stage neutralization washing section 82, alkalis such as caustic soda (NaOH) are used. The cleaning water containing the compound is used to remove acid gases (SOx, Cl) that pass through the fixed carrier layer (improving the clean water & acid gas contact efficiency). At this time, about 70% of the washing water is used to remove acid gas, and about 30% is converted to fog of 20 or less and moved to the dust collection section, and the charge of the fog is used in the three-stage electrostatic collection section 83. This removes more than 99% of acidic gas and dust remaining in the mist.

Conventional acid gas treatment systems are semi-dry reaction towers that remove calcified lime (Ca (OH) ₂ ) dilutions and remove them through neutralization with acidic gas (SOx, HCl) components. If the concentration and emission allowance standard generated through the combustion process can be applied with the above removal efficiency, it can be applied. However, biosolid fuel as shown in Table 1 [Annex 7 of the Enforcement Regulations of the Law on Saving and Recycling of Resources] If the sulfur and chlorine components contained in the product are brought in close to the legal limits, the acidic gas SOx and HCl concentrations will be more than 350 ppm and 250 ppm, respectively, making it impossible to comply with various legal regulations in Table 2.

division unit Emission allowance standard Optimal Prevention Facility Specific pollutant Hydrogen Chloride (HCl) ppm 15 (12) or less - 12 (12) or less Sulfur oxides (SO ₂ ) ppm 30 (12) or less 5 (12) or less -

* Emission allowance standard: Emission allowance standard applied from January 1, 2015 under the Air Quality Preservation Act.

Optimum Prevention Facilities: Standard Concentration of Optimal Prevention Facilities under Special Act on Improvement of Atmospheric Environment in the Capital Region

Specific pollutant: The emission limit of the specific air pollutant for a workplace that emits more than 10 tons of a single specific air pollutant per year. () Means standard oxygen concentration (% of O ₂ ).

When treating the air pollutants generated during the combustion process using the wet electrostatic precipitator 80, as in the present invention, it is possible to meet the strict legal regulations by removing acidic gas and dust with high efficiency of 99% or more.

The wet electrostatic precipitator 80 is followed by a selective catalytic reduction tower 90 to further remove nitrogen oxides from the gas from which the acid gas and the dust are removed by the wet electrostatic precipitator. Selective Catalytic Reduction (SCR) is a method of removing nitrogen oxides by supplying ammonia (NH ₃ ) to the exhaust gas and selectively reacting it with nitrogen oxides on a suitable catalyst to obtain nitrogen and water. The selective catalytic reduction catalyst (SCR catalyst) generally uses titania, alumina, silica, zirconia, etc. as a carrier of the catalyst, and an oxide such as vanadium, molybdenum, nickel, tungsten, iron, copper, etc. may be used as the active metal. .

As described above, in the energy recovery apparatus using the biosolid fuel of the present invention, only clean gas from which nitrogen oxides, sulfur oxides, and harmful gases are mostly removed is discharged to the atmosphere through the chimney. Therefore, according to the device of the present invention, it is possible to obtain the effect of protecting the worker and preventing environmental pollution.

Although the present invention has been described in detail above, this is merely to describe a preferred embodiment of the present invention and does not limit the present invention. It will be apparent to those skilled in the art that the present invention can be variously modified or modified without departing from the spirit and principles of the present invention, and thus the protection scope of the present invention is set forth in the appended claims. It should be defined as a range and an equivalent range. For example, the energy recovery apparatus of the present invention can be used not only for the combustion of biosolid fuel but also for the treatment of various solid fuels, combustible waste, municipal waste, and the like.

10: solid fuel supply storage unit
20: Traveling-Stalker
30: Incineration Boiler
40: unburned conveying conveyor
50: cutter
60: air preheater
70: generator
80: wet electrostatic precipitator
90: selective catalytic reduction tower

Claims (6)

A biofuel supply for supplying biofuel;
A treble-stocker incineration boiler which incorporates a treble-stocker for incineration of the supplied biofuel, and recovers steam by using the hot combustion gas generated in the treble-stocker;
A fine fuel conveying conveyor configured to increase combustion efficiency by circulating the fine fuel generated in the incineration boiler to the traveling-stocker;
An economizer for heating the boiler feed water supplied to the incineration boiler;
An air preheater for heating up the combustion air supplied to the incineration boiler;
A steam turbine generator for producing electricity by using steam produced in the incineration boiler;
One or more wet electrostatic precipitators connected to the incineration boiler to remove acid gases and dust generated during combustion;
Connected to the wet electrostatic precipitator, the energy recovery device using a bio-solid fuel having excellent acid gas treatment efficiency comprising a selective catalytic reduction tower for additionally removing nitrogen oxides generated in the combustion process.
According to claim 1, wherein the biofuel supply storage unit
A reservoir for storing biofuel; A supply chute for supplying the biofuel stored in the reservoir to the traveling-stocker; And at least one screw-type discharger driven by a driving motor to transfer biofuel to the feed chute by rotation of a screw, wherein the reservoir and the feed chute have a lower portion extending width in a lower direction from which biofuel is discharged. An energy recovery apparatus using biosolid fuel having excellent acid gas treatment efficiency, characterized in that it has an enlarged structure.
The energy recovery apparatus using biosolid fuel having excellent acid gas treatment efficiency according to claim 1, wherein the traveling-stocker is a cross-girder traveling-stocker manufactured by finely forming a gap in the upper plane.
The biosolid according to claim 1, wherein the incineration boiler is a water pipe type incinerator which incinerates the supplied biofuel to recover energy contained in the high temperature combustion gas as steam. Energy recovery device using fuel.
The method of claim 1, wherein the unburned conveying conveyor
A stocker conveying conveyor for re-feeding fine fines falling to the bottom of the traveling-stocker into a combustion chamber of the traveling-stocker; And
And a boiler conveying conveyor for re-injecting the fine pulverized portion of the lower hopper of the lower end of the incineration boiler into the combustion chamber.
The method of claim 1, wherein the wet electrostatic precipitator
A temperature reduction section for reducing the combustion exhaust gas discharged from the incineration boiler;
Neutralized cleaning section for neutralizing the acid gas in the exhaust gas temperature reduced by using an alkaline compound; And
An energy recovery apparatus using biosolid fuel having excellent acid gas treatment efficiency, comprising an electric dust collection section for removing residual acid gas and dust remaining as a mist.

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