US20150143809A1

US20150143809A1 - Environmentally friendly and high efficiency solid fuel production method using high-water-content organic waste, and combined heat and power system using same

Info

Publication number: US20150143809A1
Application number: US14/401,607
Authority: US
Inventors: Jae-Hyeon Ha
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-05-17
Filing date: 2013-05-15
Publication date: 2015-05-28
Also published as: ES2526716R1; WO2013172661A1; ES2526716A2; CN104508093A; RU2586332C1; ES2526716B1; KR101313314B1

Abstract

The present invention relates to an environmentally friendly and high efficiency solid fuel production method using high-water-content organic waste, and, more specifically, relates to a solid fuel production method using high-water-content organic waste, the method comprising: (a) a waste mixing step in which high-water-content organic waste and municipal waste are introduced into a Fe-based reactor and mixed; (b) a hydrolysis step in which high temperature steam is added to the reactor and the mixture of organic waste and municipal waste is placed under pressure and is then stirred in the pressurized state so as to hydrolyse the mixture; (c) a pressure-reducing step in which the steam in the reactor is discharged and the inside of the reactor is rapidly reduced in pressure and left to stand in such a way as to give the organic waste from step (b) a low molecular weight or in such a way as to enlarge the specific surface area of the municipal waste from step (b) and thereby break apart same; (d) a vacuum or differential pressure step in which the reactor is placed under vacuum or differential pressure, and the water content of the reaction product from step (c) is removed; and (e) a solid-fuel forming step in which the reaction product from step (d) is subjected to natural drying and compression moulding so as to produce a solid fuel having a water content of between 10 and 20%.

Description

TECHNICAL FIELD

The present invention relates to an environmentally friendly and high efficiency solid fuel production method using a high-water-content organic waste and a combined heat and power system using the same while noticeably reducing bad smell.

BACKGROUND ART

Organic waste such as sludge, livestock excretions in general is treated using a technology such as incineration, fermentation, direct or indirect drying, etc. In case of the incineration, it produces dioxin and a lot of harmful substance and requires a large amount of externally supplied energy along with increased installation cost, so the above-mentioned incineration has a disadvantage in that it is not economical. In addition, there is also a problem in that a large amount of energy is required so as to lower the water content from 80% to 15% in the course of direct or indirect drying, and bad smell generates from solid fuel during the drying process and after the drying process. In case of the fermentation, it have some problems in that a lot of bad smell generates, and energy efficiency is low, and it takes long time to treat waste water. The marine exhaustion of waste sludge and livestock excretions has been probated since January 2012 upon the effectiveness of the related protocol. In addition, it is expected that the marine exhaustion of food waste water which is produced in the course of treatment of food waste will be prohibited after January 2013 also.
A technology for developing a solid fuel is going on so as to treat high-water-content organic waste into energy source. In this case, it necessarily needs to lower the water content below 15%. Such a solid fuel process technology is categorized into drying and carbonization. In terms of the total amount of energy, the drying is most preferred. The bad smell generating in the course of the drying and the bad smell generating in the course of the storing and use of the produced fuel become problematic.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide an environmentally friendly and high efficiency solid fuel production method using a high-water-content organic waste which makes it possible to noticeably reduce bad smell.
It is anther object of the present invention to provide a combined heat and power system using a solid fuel produced in the above manner.

TECHNICAL SOLUTION

To achieve the above objects, as one aspect of the present invention, there is provided an environmentally friendly and high efficiency solid fuel production method using a high-water-content organic waste, comprising:
(a) a waste mixing step where a high-water-content organic waste and a municipal solid waste are inputted and mixed in a Fe-based reactor; (b) a hydrolysis step where a mixture of the organic waste and the municipal solid waste is pressurized by adding high temperature vapor into the reactor and is agitated in the pressurized state for thereby hydrolyzing the mixture; (c) a depressurization step where the reactor is controlled to remain in normal state after the interior of the reactor is suddenly depressurized by discharging the vapor from the interior of the reactor, and the mixture is crushed by depolymerizing the organic waste treated through the step (b) or by increasing the specific surface area of the municipal solid waste treated through the step (b); (d) a vacuum or differential pressure step where water is eliminated from the reactant treated through the step (c) by providing the vacuum or differential pressure condition to the reactor; and (e) a solid fuel preparation step where a solid fuel of which the water content is 10˜20% is prepared by naturally drying the reactant treated through the step (d).
To achieve the above objects, as another aspect of the present invention, there is provided a combined heat and power system which uses the solid fuel produced by the above-described method.

Advantageous Effects

The present invention is characterized in that the solid fuel may be produced by efficiently drying the internal water of the organic waste in such a way to much more effectively degrade the organic matter and bad smell with the aid of the degrading power of vapor radical and the promoted peptone reaction by the Fe reaction catalyst by inputting and mixing high-water-content organic waste and municipal solid waste into a Fe-based reactor and adding high temperature and pressure vapor and in such a way to completely crush and degrade the organic waste based on the sudden depressurization. In particular, the present invention makes it possible to produce solid fuel within a short time by greatly enhancing the efficiency of drying in such a way that the non-degraded organic waste is depolymerized through the sudden depressurization after high temperature and pressure vapor is inputted and that the specific surface area is increased by expanding the municipal solid waste.
In addition, the solid fuel produced according to the present invention may be provided as a good energy source which may substitute fossil energy thanks to its high calorific power. So, it is possible to efficiently generate electricity based on the combined heat and power generator system using the above mentioned energy source.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating a treatment system of a high-water-content organic waste according to the present invention.

FIG. 2 is an ion product change and permittivity change curve of water.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

The present invention is directed to an environmentally friendly and high efficiency solid fuel production method using a high-water-content organic waste which makes it possible to efficiently dry the internal water of the organic waste in such a way to much more effectively degrade the organic matter and bad smell with the aid of the degrading power of vapor radical and the promoted peptone reaction by the Fe reaction catalyst by inputting and mixing high-water-content organic waste and municipal solid waste into a Fe-based reactor and adding high temperature and pressure vapor and in such a way to completely crush and degrade the organic waste based on the sudden depressurization.
Hereinafter the present invention will be described in detail.
The present invention is directed to a solid fuel production method using a high-water-content organic waste, which includes (a) a waste mixing step where a high-water-content organic waste and a municipal solid waste are inputted and mixed in a Fe-based reactor; (b) a hydrolysis step where a mixture of the organic waste and the municipal solid waste is pressurized by adding high temperature vapor into the reactor and is agitated in the pressurized state for thereby hydrolyzing the mixture; (c) a depressurization step where the reactor is controlled to remain in normal state after the interior of the reactor is suddenly depressurized by discharging the vapor from the interior of the reactor, and the mixture is crushed by depolymerizing the organic waste treated through the step (b) or by increasing the specific surface area of the municipal solid waste treated through the step (b); (d) a vacuum or differential pressure step where water is eliminated from the reactant treated through the step (c) by providing the vacuum or differential pressure condition to the reactor; and (e) a solid fuel preparation step where a solid fuel of which the water content is 10˜20% is prepared by naturally drying the reactant treated through the step (d).
In the present invention, the step (a) is a step where high-water-content organic waste and municipal solid waste are inputted and mixed in a Fe-based reactor. The high-water-content organic waste is one or at least one selected from the group consisting of livestock excretions, sewage sludgy, and food waste and contains more than 80% of water content, and the municipal solid waste preferably contains kind of paper and plastics. The municipal solid waste containing such paper and plastics each having increased specific surface area reacts while expanding together with the organic waste which was depolymerized by means of the depressurization in the depressurization step, so the drying efficiency may be maximized. Since the plastics-based municipal solid waste which is a kind of a petroleum-based organic substance is contained, it is possible to enhance the low calorific power of the produced solid fuel. Preferably, the municipal solid waste contains 50˜55% by weigh of paper, and 40˜45% by weight of plastics.
In the step (a), it is preferred that the high-water-content organic waste and the municipal solid waste are inputted and mixed at a ratio of 3.5˜4:0.5˜1. In addition, it is more preferred that the high-water-content organic waste and the municipal solid waste are inputted and mixed in the reactor at a filling ratio of 70˜90%. Since high temperature and pressure vapor may be supplied from outside the reactor even though the waste, which will be treated, is inputted into the reactor at such high charging rate, and the contact-based reaction with the saturated vapor can be maintained, so that it is possible to enhance the efficiency of reaction in the highest process capacity of the wastes.
In the present invention, the step (b) is a step where a mixture of the organic waste and the municipal solid waste is pressurized by supplying high temperature of vapor into the reactor, and the mixture is agitated in the pressurized state and is hydrolyzed. The substance belonging to the organic waste is degraded and depolymerized by the pressurization, and the bad smell containing sulfuric acid is degraded, so the water content of the organic waste may be greatly lowered thanks to the high temperature while eliminating bad smell. At this moment, it is preferred that the mixture may be agitated and undergo the hydrolysis reaction after the internal pressure of the reactor is made to 20˜25 atm by supplying the vapor of 200˜250° C. into the reactor. FIG. 2 illustrates an ion product ([H+][OH−]change and permittivity change of water. Referring to FIG. 2, the ion product reaction is most active at the temperature of 200˜250° C. and shows 1,000 times higher activity as compared with the room temperature. Since the permittivity lowers to ⅓˜¼ as compared with the room temperature, a potential difference occurs between the ions, which would result in increased organic substance degradation performance. If it is below the range of the above temperature and pressure, it is hard to obtain the desired effect, and when it is above the range of the above temperature and pressure, the loss in energy may occur.
In the step (b) of the present invention, since the supply of the vapor is performed using a boiler which is connected to the reactor, the organic waste in the reactor comes into contact with the vapor from the boiler and physically and chemically reacts for thereby greatly enhancing the efficiency of the reaction without any procedure where the water changes to high temperature water in such a way that it is sprayed while coming into direct contact with the low temperature organic waste. In addition, since the vapor is supplied using the externally supplied boiler, any phenomenon where it reacts with high temperature water does not occur, so the reaction may be maintained even when the amount of the waste increases. Therefore, the mixture of the waste, which will be treated, is charged up to 70˜90% of the reactor, thus causing a contact-based reaction with the vapor.
Since the hydrolysis is performed inside of the Fe-based reactor, the efficiency of the reaction may be greatly enhanced thanks to the catalyst reaction of Fe, in particular the promoted peptone reaction in the region where the saturated vapor occupies in the reactor, and an organic membrane of 1˜2 mm is formed in the inner side of the reactor based on the process and operation of the reactor, so it is possible to prevent any corrosion due to NaCl, etc.
The step (c) of the present invention is a step where the reactor is controlled to remain in normal state after the pressure inside of the reactor is suddenly depressurized by discharging the vapor from the interior of the reactor, so that the organic waste treated through the step (b) is depolymerized or the specific surface area of the municipal solid waste treated through the step (b) is increased, and the municipal solid waste is crushed, more specifically, the step (c) is a step where the reactant pressurized by high temperature vapor is suddenly depressurized, and the volume of increased, thus depolymerizing the reactant or crushing the reactant. Since the volume of the municipal solid waste in the form of raw material is suddenly expanded through the sudden depressurization, and the specific surface area is increased, so the drying time may be shortened because such municipal solid waste is reacted with the water-content organic matter and is dried, thus greatly enhancing the efficiency of the drying. Here, it is preferred that the pressure is suddenly depressurized so that the atmosphere may become 0.9˜1.1 atm by discharging the vapor inside of the reactor for 10˜120 seconds.
In addition, the step (d) of the present invention is a step where the moisture is eliminated from the reactant treated through the step (c) by adopting the vacuum or differential pressure condition to the reactor. It is preferred that the moisture is eliminated by 5˜10% from the reactant treated through the step (c) by adopting the vacuum or differential pressure condition or 10˜15 minutes to the reactor using the vacuum pump connected to the reactor.
Also, the step (e) of the present invention is a step where the reactant treated through the step (d) is naturally dried for thereby producing solid fuel of which the water content is 10˜20%. It is preferred that the solid fuel having low calorific power of above 5,000 kcal/kg is produced.
According to another aspect, the present invention relates to the combined heat and power generator system using the solid fuel produced using the above-described method. Namely, the present invention provides the combined heat and power generator system characterized in that the solid fuel (RDF) is produced from high-water-content organic waste and municipal solid waste, and superheated vapor is produced by supplying the solid fuel to the RDF-based burner and boiler, and electricity may be generated by the steam-based power generation system which uses the superheated vapor.
Hereinafter, the present invention will be described in detail along with the exemplary embodiment.

EMBODIMENTS

Embodiment

1

A batch reactor made of a Fe material and having a dimension of 5 m³was manufactured. 3.5 tons of livestock excretions of which the water-content was 80˜85% and 0.5˜1 tones of paper Municipal Solid Waste (MSW) were inputted into the reactor as soon as possible, and the input port of the top of the reactor was closed. Upon completing the input, the livestock and the MSW were mixed, and vapor of 210° C. was supplied for the internal pressure of the reactor to become 23 atm. At this time, the inputted saturated vapor or superheated vapor reached the reaction condition within about 3˜5 minutes in the vapor supply-dedicated boiler of the top of the previously prepared reactor, so the supply of the vapor was stopped. The supplied vapor and target waste were agitated at 10˜15 rpm so that the supplied vapor and target waste physically and chemically reacted. When the reaction reached a condition below the previously set temperature and pressure while the reaction was being performed, the saturated vapor or superheated vapor was intermittently supplied so as to maintain the atmosphere of 23 atm at 210° C. The above-described state was maintained for 30˜60 minutes depending on the physical property of the treatment target in order for the peptone reaction to take place enough based on the catalyst operation by the vapor, the treatment target organic matter and the Fe-based reactor.
Next, the organic matter and the organic cell or MSW, which had not been degraded during the above-mentioned reaction, were depolymerized or crushed by quickly discharging the vapor through the vapor discharge port by opening the pressure reducing valve until the pressure became the atmospheric pressure (1-atm) within 2 minutes. About 5˜10% of the total water of the reactant was eliminated by performing the vacuum (differential pressure) process for about 10˜15 minutes using the external vacuum (differential pressure) pump so as to eliminate the water from the reactant in the reactor under the high vacuum or differential pressure condition after the processes for depolymerizing and crushing the reactant. The product produced after the reaction was moved to the natural drying place and was naturally dried, so that the final solid fuel of which the water content was 15% was produced.

Comparison Example 1

The solid fuel was produced by the method of the first exemplary embodiment, wherein the solid fuel was produced without adding the municipal solid waste (MSW).

Comparison Example 2

The solid fuel was produced by the method of the first exemplary embodiment, wherein the solid fuel was produced without performing a process for suddenly depressurizing by discharging the vapor after the pressurization.
Experiment and Result
The changes of the water content amount based on the producing time (drying time) of the solid fuel according to the above exemplary embodiment were measured using the non-treated high-water-content waste and the comparison examples 1 and 2 as the control group, and the result of the measurement is shown in Table 1.

TABLE 1

			Comparison	Comparison
Drying	High-water-content	Embodiment	Example	Example
time(hour)	waste(wt %)	1(wt %)	1(wt %)	2(wt %)

0	83	59	84	60
10	80	36	81	47
20	77	10	75	36
40	65	5	63	22
60	61	4	56	15

As shown in Table 1, in case of the comparison example 1 where the treatment was performed without the municipal solid waste, the treatment showed the almost same drying speed as the high-water-content waste which was not treated. Such a result seems to come from the fact that the reactant became a gel state phase thanks to the depolymerization of the organic matter and the external discharge of the level in the molecules, so only the water being on the top of the gel was evaporated, and the water at the bottom of the gel was not evaporated. In case of the comparison example 2 where the treatment was performed without the sudden depressurization process, it is confirmed that the drying speed during the natural drying was not affected because the increase rate of the specific surface was low. In case of the embodiment 1 of the present invention, about 10% of the water content rate was obtained after about 20 hours elapsed, which represents that the efficiency of the solid fuel manufacture is very high.
As a result, it is possible to confirm that the time elapsed until the water content rate became 10% through the sudden depressurization and vacuum processes by adding the municipal solid waste was shortened more than 2 times.
In addition, a result of the analysis with respect to the phases of the municipal solid waste used in the embodiment 1 and the comparison example 2 is as follows.

TABLE 2

		plas-				others
Foods	paper	tics	fibers	wood	rubbers	(incombustible)	total

1.07	51.3	42.6	0.07	3.2	1.74	0.02	100(%)

In addition, as a result of the measurements of the calorific values of the solid fuel prepared according to the embodiment 1 of the present invention and the solid fuel prepared according to the comparison example 1, the case of the embodiment 1 where the municipal solid waste was added showed the average heating value of 5,000 kcal/kg which was 500 kcal/kg higher than the comparison example 1. Namely, it seems that the drying speed was increased since the specific surface area was enlarged in the sudden depressurization process thanks to the paper of more than 50% and the plastics of more than 40% both contained in the municipal solid waste, and the heating value of the solid creature was increased thanks to the plastics which are the petroleum-based organic matter. The average heating value is shown in Table 3 (unit: kcal/kg).

TABLE 3

Embodiment 1	Comparison example 1	Municipal Solid Waste	Sludge

5000	4500	4700	4300

As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described examples are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.

Claims

1. An environmentally friendly and high efficiency solid fuel production method using a high-water-content organic waste, comprising:

(a) a waste mixing step where a high-water-content organic waste and a municipal solid waste are inputted and mixed in a Fe-based reactor;

(b) a hydrolysis step where a mixture of the organic waste and the municipal solid waste is pressurized by adding high temperature vapor into the reactor and is agitated in the pressurized state for thereby hydrolyzing the mixture;

(c) a depressurization step where the reactor is controlled to remain in normal state after the interior of the reactor is suddenly depressurized by discharging the vapor from the interior of the reactor, and the mixture is crushed by depolymerizing the organic waste treated through the step (b) or by increasing the specific surface area of the municipal solid waste treated through the step (b);

(d) a vacuum or differential pressure step where water is eliminated from the reactant treated through the step (c) by providing the vacuum or differential pressure condition to the reactor; and

(e) a solid fuel preparation step where a solid fuel of which the water content is 10˜20% is prepared by naturally drying the reactant treated through the step (d).

2. The method of claim 1, wherein in the step (a), the high-water-content waste is one or more than one waste selected from the wastes of livestock excrements, sewage sludgy and food waste and contains the water content of more than 80%, and the municipal solid waste contains paper and plastics.

3. The method of claim 2, wherein in the step (a), the high-water-content waste and the municipal solid waste are inputted at a ratio of 3.5˜4:0.5˜1 and are mixed.

4. The method of claim 2, wherein in the step (a), the high-water-content waste and the municipal solid waste are inputted at a filling ratio of 70˜90% into the Fe-based reactor and are mixed.

5. The method of claim 1, wherein in the step (b), the mixture of the organic waste and the municipal solid waste is pressurized so that the internal pressure of the reactor becomes 20˜25 atm by adding the vapor of 200˜250° C. to the reactor using a boiler connected to the reactor.

6. The method of claim 1, wherein in the step (c), the pressure is suddenly depressurized for the atmosphere to become 0.9˜1.1 atm by discharging the vapor from the interior of the reactor for 10˜120 seconds.

7. The method of claim 1, wherein in the step (d), the vacuum or differential pressure condition is provided to the reactor for 1015 minutes using a vacuum pump connected to the reactor for thereby eliminating 5˜10% of the water from the reactant treated through the step (c).

8. The method of claim 1, wherein the solid fuel prepared in the step (e) has a low calorific power of above 5,000 kcal/kg.

9. A combined heat and power system characterized in that electricity is generated using superheated vapor produced by supplying the solid fuel to a reactor wherein the solid fuel is produced by the method of claim 1.

10. A combined heat and power system characterized in that electricity is generated using superheated vapor produced by supplying the solid fuel to a reactor wherein the solid fuel is produced by the method of claim 2.

11. A combined heat and power system characterized in that electricity is generated using superheated vapor produced by supplying the solid fuel to a reactor wherein the solid fuel is produced by the method of claim 3.

12. A combined heat and power system characterized in that electricity is generated using superheated vapor produced by supplying the solid fuel to a reactor wherein the solid fuel is produced by the method of claim 4.

13. A combined heat and power system characterized in that electricity is generated using superheated vapor produced by supplying the solid fuel to a reactor wherein the solid fuel is produced by the method of claim 5.

14. A combined heat and power system characterized in that electricity is generated using superheated vapor produced by supplying the solid fuel to a reactor wherein the solid fuel is produced by the method of claim 6.

15. A combined heat and power system characterized in that electricity is generated using superheated vapor produced by supplying the solid fuel to a reactor wherein the solid fuel is produced by the method of claim 7.

16. A combined heat and power system characterized in that electricity is generated using superheated vapor produced by supplying the solid fuel to a reactor wherein the solid fuel is produced by the method of claim 8.