KR20180099086A - Refuse Derived Fuel By Livestock Manure Sludge And Method For Manufacturing Thereof - Google Patents

Abstract

The present invention relates to solid fuel using livestock manure sludge, and a production method thereof. According to the present invention, the solid fuel can be applied as high efficiency fuel owing to high calorific value and low water content, prevents reduction in efficiency even when reused by having the high calorific value, and suppresses release of environmental pollutants when used as fuel since detection amounts of heavy metal is remarkably low.

Description

Technical Field [0001] The present invention relates to a solid fuel using an animal husbandry sludge,

The present invention relates to a solid fuel using an animal manure sludge and a method for producing the solid fuel.

Sludge refers to solid waste from the treatment plant of sewage and wastewater treatment facilities. It has a problem in that it contains a large amount of organic matter and thus has a high value as a fuel instead of a large amount of water and thus requires a pre-combustion drying process. In addition, the sludge has irregular shape depending on the composition and composition, and has a characteristic that the water content in the sludge is not easily removed due to the microbial growth phenomenon. The water at the outermost part of the sludge is called free water and can be easily removed by conventional drying. The interstitial water is the water present between the sludge molecules and the molecules and can be removed by basic physical processes such as squeezing. Surface water is the moisture that comes into contact with the outer surface of irregular sludge molecules and is difficult to remove due to electrical attraction with the molecule. Finally, bound water is a chemical that is chemically bonded to the sludge molecules, which can not be removed by conventional processes and requires chemical treatment. Therefore, the amount of water that can be removed from the sludge through conventional drying processes is about the number of free water, pore water, and some surface number.

Generally, there are two methods of drying sludge: direct drying using heat convection and indirect drying using indirect heat to sludge. The direct drying method is a method in which water is evaporated by applying hot air directly to the sludge. There are a lot of examples to use and it is easy to use but there is a problem that the efficiency is low due to a large amount of heat released compared to other drying methods. The indirect drying method is advantageous in that the thermal efficiency is high by drying the sludge using heat conduction through the heating medium, but there is a problem that the additional facility cost is required when using the vacuum or the reduced pressure.

One of the indirect drying methods, the in-oil drying method, is a method of rapidly evaporating a distillate by using various oils having low specific heat and lower specific gravity than water. The drying method is similar to the frying technology in the food industry. It can easily remove moisture from the sludge, which has a high water content and a high degree of cohesion. Further, the amount of water and the amount of heat of the substituted oil can be obtained .

On the other hand, livestock manure has been a problem since humans have begun to raise livestock, and by the London Convention, which came into effect in August 1975, the marine dumping of wastes was totally banned from 2016, Development of an environmentally friendly treatment method of sewage and wastewater sludge has been urgently required. In addition, the need to use renewable energy instead of petroleum and coal has arisen as the Paris Agreement for 2015 has agreed to reduce greenhouse gas emissions by 5% by 2035. Livestock manure sludge composed of livestock excrement is higher value as a solid fuel requiring high caloric value because it has a higher content of organic matter than sewage sludge. However, due to the characteristics of manure, water content is as high as 90% .

Therefore, there is a need to develop a solid fuel having a low water content and a high calorie and a manufacturing method thereof by recycling sludge and livestock manure.

Korean Patent No. 10-1565704.

An object of the present invention is to provide a solid fuel having a low water content and a high calorie and being manufactured by a simple method by recycling the sludge and livestock manure using in-oil drying and a method for producing the solid fuel.

In order to solve the above-described problems, the present invention provides a sludge-containing sludge, having a calorific value of 4,000 kcal / kg or more, a water content of 10 wt% or less, chlorine (Cl) content of 0.1 wt% or less, mercury (Hg) wt% or less.

The present invention also provides a method for producing a sludge, comprising: 1 to 20 parts by weight of sludge based on 100 parts by weight of an oil; And heating the oil into which the sludge has been introduced to 100 to 150 ° C.

The solid fuel according to the present invention can be utilized as a fuel having a high efficiency due to a high calorific value and a low moisture content and can prevent deterioration of efficiency even when reused due to high calorific value and remarkably low detection amount of heavy metal, There is an effect of preventing the discharge of the exhaust gas.

FIG. 1 shows the results of measurement of evaporation amount according to the drying temperature of each oil.
Fig. 2 shows the drying efficiency evaluation results according to the drying temperature, the drying time and the sludge amount of the vegetable oil and the animal oil.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the present invention, the terms "comprising" or "having ", and the like, specify that the presence of a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Hereinafter, the present invention will be described in detail with reference to the drawings, and the same or corresponding components are denoted by the same reference numerals regardless of the reference numerals, and a duplicate description thereof will be omitted.

Hereinafter, the solid fuel according to the present invention will be described in detail.

The solid fuel according to the present invention comprises sludge and has a calorific value of 4,000 kcal / kg or more, a water content of 10 wt% or less, a chlorine (Cl) content of 0.1 wt% or less, a mercury (Hg) content of 0.0006 wt% to be.

As an example, the calorific value of the solid fuel may be 4,200 to 6,000 kcal / kg, 4,500 to 6,800 kcal / kg, 4,700 to 6,500 kcal / kg, 4,800 to 6,000 kcal / kg when measured using a Cl calorimeter 6,300 kcal / kg, 4,900 to 6,100 kcal / kg, 5,000 to 5,900 kcal / kg, 5,100 to 5,800 kcal / kg or 5,200 to 5,500 kcal / kg. The solid fuel according to the present invention satisfies the above-mentioned calorific value and thus can be utilized as a fuel having an efficiency as high as 4,220 kcal / kg, which is the calorific value of conventional wood pellets.

As an example, the chlorine content of the solid fuel may range from 0.001 to 0.1 wt%, 0.005 to 0.08 wt%, 0.01 to 0.07 wt%, 0.015 to 0.06 wt%, 0.02 wt% To 0.05 wt% or 0.03 to 0.043 wt%, and the mercury content may be 0.00005 wt% or less, 0.00003 wt% or 0.000001 to 0.00001 wt%, and substantially no mercury may be detected.

Wherein the solid fuel has a cadmium (Cd) content of 0.005 wt% or less, a lead (Pb) content of 0.1 wt% or less, an arsenic content of 0.005 wt% or less, a chromium (Cr) content of 0.07 wt% ≪ / RTI >

As one example, the solid fuel has a cadmium content of 0.004 wt% or less, 0.001 wt% or less, 0.0005 wt% or less, 0.00001 to 0.0001 wt%, or 0.000001 to 0.000005 wt%, when detected by PXRF (Portable X-Ray Fluorescence) And substantially no cadmium may be detected. The lead content may be 0.08 wt% or less, 0.05 wt% or less, 0.03 wt% or less, 0.001 to 0.03 wt% or 0.001 to 0.029 wt%. The arsenic content may be 0.004 wt% or less, 0.001 wt% or less, 0.0005 wt% or less, 0.00001 to 0.0001 wt% or 0.000001 to 0.000005 wt%, and substantially no arsenic may be detected. The chromium content may be 0.01 wt% or less, 0.005 wt% or less, 0.004 wt% or less, 0.001 wt% or less, 0.0005 wt% or less, 0.00001 to 0.0001 wt% or 0.000001 to 0.000005 wt% It may not be detected.

As one example, the solid fuel may have a sulfur (S) content of 0.1 wt% or less when detected by PXRF (Portable X-Ray Fluorescence). Specifically, the sulfur content may be 0.05 wt% or less, 0.08 wt% or less, 0.05 wt% or less, 0.03 wt% or less, 0.001 to 0.03 wt% or 0.001 to 0.025 wt%.

In the solid fuel according to the present invention, when the content of the heavy metal (chlorine, mercury, cadmium, lead, arsenic, chromium, sulfur) satisfies the above range, substantially no heavy metal is detected, And the generation of substances and environmental pollutants can be markedly lowered.

Hereinafter, the solid fuel manufacturing method according to the present invention will be described in detail.

A method for producing a solid fuel according to the present invention comprises the steps of: 1 to 20 parts by weight of livestock manure sludge on the basis of 100 parts by weight of an oil; And heating the oil into which the sludge has been introduced to 100 to 150 ° C. Specifically, the sludge is used in an amount of 1 to 15 parts by weight, 1.5 to 10 parts by weight, 2 to 9 parts by weight, 3 to 8 parts by weight, 3.5 to 7.5 parts by weight, 4 to 7 parts by weight, 5.5 to 6.5 parts by weight Or 6 parts by weight. When the content of the oil and livestock manure sludge is within the above range, the solid fuel can be produced which effectively lowers the water content and exhibits an excellent calorific value.

In the heating step, the heating temperature may be 105 to 145 ° C, 110 to 140 ° C, 115 to 138 ° C, 120 to 135 ° C, 125 to 133 ° C or 130 ° C. It is possible to effectively produce a solid fuel that exhibits an excellent calorific value while effectively lowering the water content when the heating temperature is lowered during drying in oil.

As one example, the method for producing a solid fuel according to the present invention may include the step of charging 30 g of livestock manure sludge on the basis of 500 g of slurry, followed by heating to 130 캜.

The oil may include one or more of vegetable oil, animal oil, mineral oil and mixed oil. Specifically, the oil may be a vegetable oil or an animal oil, and more specifically, vegetable oil may be best suited to oil, considering ease of mass production, ease of collection, environmental friendliness, and stability to human body.

The oil may comprise refined waste oil. According to the current law, waste containing more than 5% of oil in waste is classified as designated waste. Waste oil can not be burned in places other than incinerator because there are many impurities in the waste. It is difficult to burn due to high viscosity, When using fuel oil, it is necessary to refine it. In the present invention, the solid fuel can be produced by utilizing the waste oil, thereby reducing the manufacturing cost and preventing environmental pollution due to the recycling of the waste oil.

In the present invention, the heating step may be performed for 5 to 50 minutes. Specifically, the heating may be performed for 10 to 45 minutes, 12 to 40 minutes, 15 to 35 minutes, 20 to 30 minutes, 22 to 28 minutes, or 25 minutes. When the heating is performed for the time in the above range, the solid fuel can be produced which effectively lowers the water content and exhibits an excellent calorific value.

Hereinafter, the present invention will be described in more detail by way of examples. It should be noted, however, that the following examples are illustrative of the invention and are not intended to limit the scope of the invention.

Example  One

500 g of olive oil as a vegetable oil and 25 g of animal manure sludge (poultry) were put into a direct-drying in-oil drying apparatus and dried at 130 ° C for 25 minutes to prepare dried sludge. Then, the dried sludge was pulverized and then molded into a pellet molding machine to produce a solid fuel.

Example  2

A solid fuel was prepared in the same manner as in Example 1, except that lard oil was used as the animal oil instead of the vegetable oil.

Comparative Example  One

A solid fuel was prepared in the same manner as in Example 1, except that light oil was used instead of vegetable oil.

Comparative Example  2

A solid fuel was prepared in the same manner as in Example 1, except that engine oil was used instead of vegetable oil.

Experimental Example  1: Measurement of evaporation amount according to drying temperature of oil

In order to measure the amount of evaporation according to the drying temperature of the vegetable oil, animal oil, mineral oil and mixed oil used in Examples 1, 2, Comparative Example 1 and Comparative Example 2, olive oil, lard oil, light oil and engine oil Each was measured at 110 캜, 120 캜 and 130 캜 for 30 minutes. As a result, as shown in Fig. 1, when a mineral oil (Fig. 1-c) was measured for 30 minutes, it showed a remarkable reduction from 12 g to 24 g, while the vegetable oil (Fig. 1-a), animal oil -b) and the mixed oil (Fig. 1-d) showed a relatively small amount of evaporation with a change of about 0.1 g for 30 minutes. In the case of diesel oil, the amount of evaporation in the oil was large and the deviation of the result was relatively large. Therefore, it was found that the diesel oil was inadequate as a heating medium because of the possibility of causing a later error. There were many impurities and a phenomenon of boiling of the foam and a phenomenon of sticking to the inner wall of the container, which were found to be unsuitable as a heating medium. Therefore, it has been confirmed that vegetable oils and animal oils are suitable as heating media for drying in oil.

Experimental Example  2: Vegetable oil and Of animal oil  Drying temperature, drying time and Sludge  Evaluation of Drying Efficiency by Amount (Measurement of Moisture Content)

In order to evaluate the drying efficiency according to the drying temperature, the drying time and the amount of the sludge of each of the vegetable oil and the animal oil in the production of the solid fuel according to Examples 1 and 2, 500 g of each of olive oil and lard oil was prepared, The drying temperature was controlled at 110 캜, 120 캜 and 130 캜, and the amount of sludge was controlled to 10 g, 20 g and 30 g, and the water content of the sludge was measured for 50 minutes. The results are shown in FIG. 2. In FIG. 2, A, B and C show the case where the amounts of sludge are 10 g, 20 g and 30 g, respectively, and I, II and III show the cases where the drying temperatures are 110 ° C., 120 ° C. and 130 ° C. . As a result, the drying rate of animal oil (Animal) was about 5% faster than that of vegetable oil. Also, the drying rate was faster than that of 20g and 30g when the amount of sludge was 10g and the drying temperature was 110 ℃, but the drying rate was similar regardless of the amount of sludge as the drying temperature increased. As a result of the water content, it took 50 minutes to completely dry the sludge, but it was found that the water content of 10% or less, which is the drying condition of the solid fuel, was satisfied within about 20 minutes.

In the present invention, the water content was measured according to the following formula 1 according to the time (t).

[Formula 1]

As a result, considering that vegetable oil is easier to mass-produce than animal oil, easy to collect, environmentally friendly, and stable to human body, when 30 g of sludge is dried at 130 ° C for 25 minutes, It was found that the solid fuel having the highest efficiency can be produced.

Experimental Example  3: Calorific value and composition evaluation of manufactured solid fuel

In order to evaluate the efficiency and characteristics of the solid fuel according to the present invention, the calorific value of the solid fuel prepared according to Example 1 was measured, and heavy metals and pollutants in the solid fuel were analyzed.

Specifically, the calorific value was measured using a Cl calorimeter (Cl Calimeter, IKA). Cl calorimeter The internal temperature of the Bomb was maintained at 19 ° C using a chiller and 99% O ₂ was used as the combustion gas. 0.1 to 0.4 g of the solid fuel sample was sampled, the precise weight was input to the apparatus, the crucible with the sample was placed in the prepared bomb, and the heating filament was connected by a heating wire having a heat quantity of 50 kcal / kg. The calorific value was calculated by using the internal program of the change of the temperature of the primary bomb and the external cooling water.

Analysis of heavy metals and contaminants was performed using Sl Titan LE PXRF (Portable X-Ray Fluorescence, Bruker). Eight heavy metals that can occur when solid fuel pellets are burned, and sulfur and nitrogen oxides, which are considered to be the main causes of air pollution, were analyzed by PXRF for 60 seconds. The measurement method was Geochem general which can analyze all measurement ranges.

As a result, the calorific value was 5,211 kcal / kg, and the results of elemental measurement by PXRF analysis are shown in Table 1 below.

Heavy metal type Detection result (wt%) Chlorine (Cl) 0.0428 Sulfur (S) 1.4256 Mercury (Hg) 0 Cadmium (Cd) 0 Lead (Pb) 0.028 Arsenic (As) 0 Chromium (Cr) 0

Heavy metal type Detection standard value (wt%) Chlorine (Cl) Max. 0.1 Sulfur (S) Max. 0.1 Mercury (Hg) Max. 0.0006 Cadmium (Cd) Max. 0.005 Lead (Pb) Max. 0.1 Arsenic (As) Max. 0.005 Chromium (Cr) Max. 0.07

<Fuel conversion standard of wood pellet of thermal power plant>

It can be seen from Table 1 that most of the heavy metals are detected below the reference value indicated in the fuel conversion standard of the wood pellet currently used as the alternative fuel in the thermal power plant (Table 2). From these results, it was confirmed that the solid fuel according to the present invention exhibits an excellent calorific value and can be used as a fuel with excellent efficiency as the emission of environmental pollutants is significantly lowered.

Experimental Example  4: Wood flour  Measurement of calorific value of solid fuel according to addition amount

To measure the calorific value of the solid fuel according to the present invention and the conventional calorific value of wood pellets (wood fuel), the solid fuel was prepared by the method according to Example 1, except that the samples 1 to 6 having different amounts of wood powder were prepared and dried The calorific value according to the mixing ratio of sludge and wood powder was measured. The results are shown in Table 3 below.

division Dry sludge (wt%) Wood powder (wt%) Calorific value (kcal / kg) Sample 1 100 0 5,211 Sample 2 80 20 5,090 Sample 3 60 40 4,861 Sample 4 40 60 4,672 Sample 5 20 80 4,543 Sample 6 0 100 4,220

According to the results shown in the above Table 3, in the case of Sample 1 (solid fuel according to Example 1) which does not contain wood powder, the calorific value was the highest at 5,211 kcal / kg and the calorific value was found to decrease as the wood powder content increased . Accordingly, it can be seen that the solid fuel according to the present invention can be utilized as a fuel of superior efficiency that can replace conventional wood pellets.

Claims (7)

Containing livestock manure sludge,
The calorific value is 4,000 kcal / kg or more,
The water content is 10 wt% or less,
The content of chlorine (Cl) is 0.1 wt% or less,
And a mercury (Hg) content of 0.0006 wt% or less.
The method according to claim 1,
The solid fuel,
The content of cadmium (Cd) is 0.005 wt% or less,
The lead (Pb) content is 0.1 wt% or less,
The content of arsenic (As) is 0.005 wt% or less,
And a chromium (Cr) content of 0.07 wt% or less.
The method according to claim 1,
Wherein the solid fuel has a sulfur (S) content of 0.1 wt% or less.
Adding 1 to 20 parts by weight of animal manure sludge on the basis of 100 parts by weight of an oil; And
And heating the oil feedstock to 100 to 150 ° C.
5. The method of claim 4,
Wherein the oil comprises at least one of vegetable oil, animal oil, mineral oil and mixed oil.
5. The method of claim 4,
Characterized in that the oil comprises refined waste oil.
5. The method of claim 4,
Wherein the heating step is performed for 5 to 50 minutes.

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