KR20170098658A - Improved heating value lignocellulosic bio-coal and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a lignocellulose bio-coal having improved caloric value and a manufacturing method thereof. The lignocellulose bio-coal has excellent energy density and energy efficiency, shows high combustion efficiency and has improved caloric values.

Description

TECHNICAL FIELD [0001] The present invention relates to a lignocellulosic bio-coal having improved heat generation and an improved heating value lignocellulosic bio-coal and manufacturing method thereof,

More particularly, the present invention relates to a lignocellulosic bio-coal having an improved calorific value and an improved energy density and energy efficiency, Cellulose-based bio-coal and a process for producing the same.

The Ministry of Environment revised the "Law Concerning the Promotion of Resource Conservation and Recycling" on July 22, 2014. According to the amendment, management of solid fuels, which are attracting attention as renewable energy, has been strengthened, and a management system has been established throughout the entire process from importing, manufacturing, and use of solid fuel products. It is estimated that it provided. The main contents of the amendment include mandatory quality inspection and quality labeling for solid fuel products, compulsory periodic inspection of facilities for manufacturing and using solid fuel products, manufacture, import and use of solid fuel products .

According to the amendment of the Enforcement Regulations of the Recycling Law, solid fuel products are classified as Solid Refuse Fuel (SRF) and Bio Solid Refuse Fuel (Bio-SRF). SRFs include municipal solid waste (including waste furniture), waste synthetic fibers, waste tires, waste synthetic resin except for automobile trash remnants, waste rubber, and fuel mixed with raw materials for manufacturing bio solid fuel products. Bio-SRF can be used to remove wastes, agricultural wastes (rice husks, rice bran, corn bran, etc.), herbaceous waste, scrap wood (except those used for railway sleepers and poles), peanut bark, walnut bark, palm bark, And vegetable residues such as peel (excluding food). SRF and Bio-SRF can be sold as fuel for private boilers, cogeneration plants, and industrial facilities.

There is a big difference in the quality specifications of SRF, Bio-SRF and wood pellets. The bio-SRF quality criteria, which can be contrasted with the quality of wood pellets, are as follows: Bio-SRF has a calorific value of less than 3,000 kcal / kg, ash less than 15%, chlorine less than 0.5% The sulfur content should not be more than 0.6% by weight. For wood pellets, the calorific value based on grade 4 pellets should be 4,040 kcal or higher, the ash content should be less than 6%, the chlorine content less than 0.05%, and the sulfur content less than 0.05%. According to these quality class standards, Bio-SRF can be compared to the quality and quality standards of wood pellets grade 4 pellets, and because of looser standards than wood pellets grade 4 pellets, the demand for Bio-SRF It can be said that it satisfies the conditions that can be further expanded.

In particular, since Empty Fruit Bunch (EFB) and Palm Kernel Shell (PKS) among the oil palm biomass are in the category of Bio-SRF, the possibility of oil palm biomass to expand as demand for Bio-SRF is much greater in Korea . Some companies have already imported PKS from the subtropical region and used it as fuel for power generation. For reference, the quality standard of Bio-SRF applies even if some sawdust are mixed with PKS or EFB.

On the other hand, in order to use lignocellulosic biomass including PKS and EFB as fuels for combustion, it is necessary to reduce the logistical cost by increasing the bulk density as much as possible, and also to increase the energy density thereof. In order to do this, it is necessary to increase the efficiency as a fuel by applying an energy optimization technique such as torrefaction, but once the lignocellulosic biomass is semi-carbonized, the lignin decomposition, which acts as a natural adhesive, There is a problem that pellet molding becomes difficult.

A conventional method for producing bio-coal using seaweeds has been proposed. This configuration has the effect of significantly reducing the amount of harmful gases such as carbon dioxide and reducing combustion instability. However, energy density and energy efficiency There is a problem that it is difficult to exhibit an effect of exhibiting a high combustion efficiency and an improvement in a calorific value.

Korea Registration No. 10-1580621 (Dec. 21, 2015)

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a lignocellulose having an improved energy density and energy efficiency, a high combustion efficiency and an improved calorific value, And a method for producing the same.

In order to solve the above-described problems, the present invention provides a method for producing bio-coal, comprising the steps of pelletizing a lignocellulosic biomass to produce biomass pellets, and performing a semi-carbonization process on the biomass pellets to produce bio- The semi-carbonization process is performed at 200 ° C to 320 ° C under anoxic and atmospheric pressure, and the lignocellulosic biomass includes at least one selected from Empty fruit bunch (EFB) and Palm kernel shell (PKS) Provided is a method for producing lignocellulosic bio-coal having improved heating value.

According to a preferred embodiment of the present invention, the step of preparing the biomass pellet may further include a step of pre-treating the lignocellulosic biomass.

According to another preferred embodiment of the present invention, the pre-treating step comprises drying the EFB to less than 15% moisture content when the lignocellulosic biomass is EFB, and processing the length of the EFB to less than 60 mm . ≪ / RTI >

According to another preferred embodiment of the present invention, the pretreatment may comprise pulverizing to less than 70% of the initial volume when the lignocellulosic biomass is PKS.

According to another preferred embodiment of the present invention, the step of preparing the biomass pellet may be performed at 100 ° C to 170 ° C for 30 minutes to 90 minutes.

According to another preferred embodiment of the present invention, in the semi-carbonization step, the internal temperature is raised from 20 ° C to 25 ° C at a rate of 7 ° C to 13 ° C / min, the inert gas is supplied at a rate of 0.03 to 0.07 L / min As shown in FIG.

According to another preferred embodiment of the present invention, the step of preparing the bio-coal may be performed at 230 ° C to 320 ° C.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a process for producing a semi-carbonized EFB pellet comprising a semi-carbonized Empty fruit bunch pellet or semi-carbonized PKS (Palm kernel shell) pellet having a calorific value of 4,000-6,500 kcal / kg, , Mass yield of 38 to 92% according to the following formula 1 and energy yield (Enerhy yield) of 58 to 97% according to the following relational formula 2 and half-carbonized PKS pellets according to the following relational formula 1 Wherein the mass yield is 40 to 90%, and the energy yield according to the following formula 2 is 51 to 96%.

[Relation 1]

In the above relational expression 1, M _torrefaction represents the mass of the bio-coal after the semi-carbonization, and M _raw represents the mass of the bio-coal before the semi-carbonization.

[Relation 2]

In the above-mentioned relational expression 2, H _hv represents a high calorific value.

According to a preferred embodiment of the present invention, the bio-coal may be a semi-carbonized EFB pellet having an energy denitance of 1.03 to 1.42 according to the following relation 3, and in the case of semi-carbonized PKS pellets, May be 1.06 to 1.34.

[Relation 3]

According to another preferred embodiment of the present invention, when the bio-coal is semi-carbonized EFB pellets, durability according to the following formula 4 may be 70 to 92%, and in the case of semi-carbonized PKS pellets, durability May be 60 to 85%.

[Relation 4]

The durability was measured by weighing 500 g of bio-coal pellets sieved with a diameter of 3.15 mm according to ISO 3310-2 to 0.01 g, putting it into a durability tester based on CEN / TS 15210-1 regulation, Min, and the weight (g) of the bio-pellet after sieving with a sieve having a diameter of 3.15 mm was measured.

According to another preferred embodiment of the present invention, the semi-carbonized EFB pellet comprises 46 to 67.5% by weight of carbon, 18.5 to 43% by weight of oxygen, 4 to 6.15% by weight of hydrogen and the balance nitrogen, And the semi-carbonized PKS pellets may comprise 51.5-67 wt% carbon, 23-40 wt% oxygen, 4.2- 6.2 wt% hydrogen and balance nitrogen, sulfur, ash.

According to another preferred embodiment of the present invention, the calorific value of the bio-coal may be 5,000 to 6,300 kcal / kg.

INDUSTRIAL APPLICABILITY The lignocellulosic bio-coal of the present invention having an improved calorific value and its production method are excellent in energy density and energy efficiency, exhibit high combustion efficiency and have an improved calorific value.

1 is a photograph of a lignocellulosic biomass according to a preferred embodiment of the present invention.
2 is a photograph of a pellet molding apparatus according to a preferred embodiment of the present invention.
3 is a plan view and a three-dimensional structure image according to a preferred embodiment of the present invention.
4 is a photograph of a bio-coal production apparatus according to a preferred embodiment of the present invention.
5 is a photograph of a durability tester according to a preferred embodiment of the present invention.
6 is a photograph of coalized PKS and bio coal pellets according to Comparative Example 3 of the present invention.
7 is a photograph of the coalized EFB and bio-coal pellets according to Comparative Example 4 of the present invention.
8 is a photograph of PKS bio-coal and EFB bio-coal according to a preferred embodiment of the present invention.
FIG. 9 is a graph of carbon, hydrogen, and oxygen mole ratios by temperature according to a preferred embodiment of the present invention.
10 is a graph showing an industrial analysis result according to temperature according to a preferred embodiment of the present invention.
11 is a graph showing calorific value of bio-coal according to a preferred embodiment of the present invention.
12 is a graph illustrating a heating rate increase rate of bio-coal according to a preferred embodiment of the present invention.
13 is a graph showing the durability of bio-coal according to a preferred embodiment of the present invention.
FIG. 14 is a graph of pyrolysis characteristics of bio-coal according to a preferred embodiment of the present invention.
15 is a graph showing a mass yield and an energy yield of bio-coal according to a preferred embodiment of the present invention.
16 is a graph of energy density of bio-coal according to a preferred embodiment of the present invention.

Hereinafter, the present invention will be described in more detail.

As described above, the conventional structure has the effect of significantly reducing the amount of harmful gases such as carbon dioxide and reducing the combustion instability. However, it has an excellent energy density and energy efficiency, a high combustion efficiency and a high heating value There was a problem that it was difficult to show the effect.

Accordingly, the present invention relates to a method for producing biomass pellets by pelletizing a lignocellulosic biomass to produce a biomass pellet and a step of performing a semi-carbonization process on the biomass pellet to produce bio-coal, Characterized in that the lignocellulosic biomass is carried out at atmospheric pressure at 200 ° C to 320 ° C and the lignocellulosic biomass comprises at least one selected from EFB (Empty fruit bunch) and PKS (Palm kernel shell) The present invention provides a method for producing bio-coal. As a result, the energy density and the energy efficiency can be different from the conventional invention, the high combustion efficiency can be achieved, and the heat generation can be improved.

First, the step of producing biomass pellets by pelletizing the lignocellulosic biomass will be described.

The lignocellulosic biomass may be any lignocellulosic biomass that can be conventionally pelletized to produce coal. The lignocellulosic biomass is preferably selected from Empty fruit bunch (EFB) and Palm kernel shell And may include one or more species.

The method may further comprise pretreating the lignocellulosic biomass prior to the step of preparing the biomass pellet.

Drying the EFB to a water content of less than 15%, preferably less than 13%, when the lignocellulosic biomass is an EFB (Empty fruit bunch), and drying the EFB to a length less than 60 mm, preferably less than 50 mm To about < RTI ID = 0.0 > 1. < / RTI > If the moisture content is more than 15%, the pellet forming yield may drop to 50% or less, and if the pellet length is more than 60 mm, the pellets may not pass through the pellet die due to entanglement between the fibers. .

And, when the lignocellulosic biomass is a PKS (Palm kernel shell), it may include pulverizing to less than 70% of the initial volume, preferably less than 60%. If the volume after crushing is 70% or more of the initial volume, pellets may not be easily manufactured.

The step of preparing the biomass pellet is not particularly limited as long as it is a condition for producing the pellet, and preferably at 100 ° C to 170 ° C, more preferably at 120 ° C to 170 ° C due to frictional heat between the pellet roll and the biomass, The pellet molding operation can be carried out at 150 DEG C for 30 to 90 minutes, preferably 40 to 80 minutes, to produce viromass pellets. If the temperature is less than 100 ° C, the durability of the pellet may be poor. If the temperature is more than 170 ° C, a risk of fire due to excessive frictional heat may occur.

On the other hand, when the biomass is passed through the die of the pelletizing apparatus as it is in the form of powder when the pellet is molded, the molding yield of the pellet may be drastically decreased. After 5 minutes or more, If it is not discharged, the frictional heat may cause fire.

Next, the step of producing the bio-coal by performing the semi-carbonization process on the biomass pellet will be described.

The semi-carbonization process may be performed at a temperature of a conventional semi-carbonization process, preferably at 200 ° C to 320 ° C under anoxic and atmospheric pressure, preferably at 230 ° C to 320 ° C under anaerobic and atmospheric pressure. If the temperature of the semi-carbonization process is less than 200 ° C, a low calorific value and a low energy density may occur. If the temperature exceeds 320 ° C, the durability may be lowered.

The semi-carbonizing step is a step of heating the internal temperature at a rate of 20 ° C to 25 ° C, preferably 21 ° C to 24 ° C, and 7 ° C to 13 ° C / min, preferably 8 ° C to 12 ° C / . If the internal temperature is raised from below 20 ° C, there is a problem that excessive energy is consumed at the time of heating. If the internal temperature is raised above 25 ° C, When the temperature is raised from a temperature exceeding 100 ° C, the surface may become excessively semi-carbonated as compared with the inside. If the heating rate is less than 7 DEG C / min, energy consumption is increased and the process time may become longer. If the heating rate is higher than 13 DEG C / min, problems may occur as long as the half- .

The semi-carbonization step is not particularly limited as long as the inert gas is supplied at the half-carbonization step, preferably at a rate of 0.03 to 0.07 L / min, more preferably at a rate of 0.04 to 0.06 L / min Can be performed. If the rate of feeding the inert gas is less than 0.03 L / min, the biomass may be burned to cause a fire problem. If the inert gas is supplied at a rate of more than 0.07 L / min, the manufacturing cost may increase, .

On the other hand, the inert gas can be used without limitation as long as it is an inert gas generally used in a semi-carbonization process. Preferably, nitrogen gas may be used, but is not limited thereto.

The present invention relates to a process for the production of a catalyst having a specific calorific value and comprising a semi-carbonized Empty fruit bunch (EFB) pellet or a semi-carbonized PKS (Palm kernel shell) pellet and having a specific mass yield and a specific energy yield Thereby providing a lignocellulosic bio-coal having improved calorific value.

[Relation 1]

In the above relational expression 1, M _torrefaction represents the mass of the bio-coal after the semi-carbonization, and M _raw represents the mass of the bio-coal before the semi-carbonization.

[Relation 2]

In the above-mentioned relational expression 2, H _hv represents a high calorific value.

Specifically, the lignocellulosic bio-coal has a calorific value of 4,000 to 6,500 kcal / kg, and a calorific value of 5,000 to 6,300 kcal / kg. This shows a much higher calorific value than that of a typical bio-coal having a calorific value of less than 5,000 kcal / kg. If the calorific value is out of the range of 4,000 ~ 6,500 kcal / kg, there is a problem that coal is not suitable for use as fuel.

On the other hand, when the lignocellulosic bio-coal is a semi-carbonized EFB pellet, mass yield may be 38 to 92%, preferably mass yield may be 38 to 65% according to the relationship 1, 2, the energy yield may be 58 to 97%, preferably the energy yield may be 58 to 85%.

If the lignocellulosic bio-coal is a semi-carbonized PKS pellet, the mass yield may be 40 to 90%, preferably 40 to 75%, according to the relationship 1, 2, the energy yield (Enerhy yield) may be 51 to 96%, preferably 51 to 78%.

Accordingly, when the bio-coal is a semi-carbonized EFB pellet, the energy density according to the following Equation 3 may be 1.03 to 1.42, preferably the energy density is 1.19 to 1.42, and the bio- In case of PKS pellets, the energy denity according to the following formula 3 may be 1.06 to 1.34, preferably 1.08 to 1.34.

[Relation 3]

If the energy density is less than the above range, there may arise a problem that the desired energy density improvement is not exhibited. If the energy density exceeds the above range, the semi-carbonization temperature must be relatively increased, resulting in poor durability .

When the bio-coal is a semi-carbonized EFB pellet, the durability according to the following formula 4 may be 70 to 92%, preferably 70 to 82%. If the bio-coal is a semi-carbonized PKS pellet, The durability according to the relational expression 4 may be 60 to 85%, preferably 60 to 73%.

[Relation 4]

The durability was measured by weighing 500 g of bio-coal pellets sieved with a diameter of 3.15 mm according to ISO 3310-2 to 0.01 g, putting it into a durability tester based on CEN / TS 15210-1 regulation, Min, and the weight (g) of the bio-pellet after sieving with a sieve having a diameter of 3.15 mm was measured.

If the durability is less than the above range, the durability may be poor and the bio-coal may be poorly transported. If the durability is out of the above range, the semi-carbonization temperature should be lowered to lower the energy density. .

On the other hand, the semi-carbonized EFB pellets contain 46 to 67.5% by weight of carbon, 18.5 to 43% by weight of oxygen, 4 to 6.15% by weight of hydrogen and residual amounts of nitrogen, sulfur and ash, preferably 54 to 67% 19 to 33% by weight, hydrogen to 4.2 to 5.9% by weight, and balance nitrogen, sulfur and ash. The semicarbonated PKS pellets may also contain 51.5 to 67% by weight of carbon, 23 to 40% by weight of oxygen, 4.2 to 6.2% by weight of hydrogen and a balance of nitrogen, sulfur and ash, preferably 54.5 to 66.5% 23 to 36 wt%, hydrogen to 4.3 to 5.9 wt%, and balance nitrogen, sulfur, ash.

Hereinafter, the present invention will be described with reference to the following examples. The following examples are provided to illustrate the invention, but the scope of the present invention is not limited by the following examples.

[ Example ]

Example  One: Lignocellulose system  Manufacture of bio-coal

(One) Biomass  Manufacture of pellets

The PKS generated as a by-product in the Indonesian palm oil extraction and purification process as shown in FIG. 1B was pulverized to an average volume of less than 60% based on the initial volume as a pretreatment step. Thereafter, the biomass pellet was prepared using the pellet molding apparatus (DUCO, Korea) shown in Fig. 2 at a temperature of 135 ° C due to the self-heating frictional heat. The pellet molding apparatus was a flat die system, and the structure of the pellet die was a pellet die having a structure of discharging in three stages as shown in FIG.

(2) Lignocellulose system  Manufacture of bio-coal

The biomass pellets were semi-carbonized through a manufacturing equipment of bio-coals (New Materials Laboratory, Pulp and Paper, Gyeongsang National University) as shown in FIG. 4 to prepare lignocellulosic bio-coal. Specifically, the inside of the reactor was set to an oxygen-free and an atmospheric pressure state, and nitrogen was supplied to the inert gas at a flow rate of 0.05 L / min. After charging the biomass pellets, the temperature inside the reaction vessel was raised from 24 ° C at a rate of 10 ° C / min, and the reaction was carried out at 200 ° C for 30 minutes to prepare lignocellulosic biocarbons.

Example 2

The lignocellulosic bio-coal was produced in the same manner as in Example 1, except that the temperature of the semi-carbonization was changed from 200 캜 to 250 캜.

Example  3

The lignocellulosic bio-coal was produced in the same manner as in Example 1, except that the temperature of the semi-carbonization was changed from 200 ° C to 230 ° C.

Example  4

Except that PKS was changed to EFB and the water content of the EFB was naturally dried to 10% by the pretreatment step and the dried EFB was cut to have a length of less than 50 mm to use as the lignocellulose bio- Coal was produced.

Example  5

The lignocellulosic bio-coal was produced in the same manner as in Example 4, except that the temperature of the semi-carbonization was changed from 200 캜 to 250 캜.

Example  6

Lignocellulosic bio-coal was produced in the same manner as in Example 4, except that the temperature of semi-carbonization was changed from 200 캜 to 300 캜.

Comparative Example  One

Carbonization was carried out in the same manner as in Example 1, except that the semi-carbonization process was not performed.

Comparative Example  2

Carbonization was carried out in the same manner as in Example 4 except that the semi-carbonization process was not performed.

Comparative Example 3

The lignocellulosic bio-coal was produced under the same conditions as in Example 1 except that the semi-carbonization process was performed first and then the pellet was produced.

Comparative Example  4

The lignocellulosic bio-coal was produced under the same conditions as in Example 4, except that the semi-carbonization process was performed first and then the pellet was produced.

Experimental Example  1: Analysis of quality characteristics

In order to analyze the quality characteristics of the lignocellulosic bio-coal produced according to Examples 1 to 6 and Comparative Examples 1 to 4, Chlorine content, nitrogen content, sulfur content and calorific value were measured.

An elemental analyzer (EA1110, CE Instruments) was used for elemental analysis of pellets before and after bio-coal production. The sample was crushed to a size that passed through a 1 mm metal mesh, and 100 mg was taken. The contents of carbon (C), hydrogen (H), nitrogen (N), and sulfur (S) were measured using an elemental analyzer. The oxygen content was calculated using the following equation (1).

[Equation 1]

O (%) = 100-C (%) -H (%) -N (%) -S (%

Before and after bio-coal production, the intrinsic moisture, fixed carbon, ash, and volatile matter contained in pellets were analyzed based on TGA (SDT Q600, TA Instruments) based on Korean Industrial Standard KS E 3705. The general calculation method for combustion fuel was calculated as 'moisture + volatile matter + fixed carbon + ash = 100'.

(1) Moldability evaluation

The lignin component constituting the woody biomass is heated at a temperature of 120 to 150 ° C. in the pellet molding step, and thus acts as a natural adhesive, whereby the pellet can be molded without a separate adhesive. However, the lignin structure undergoes depolymerization and recondensation through the bio - coal process, and through this process, the lignin structure is transformed into the charcoal structure and the inherent adhesion is lost. As a result, woody biomass produced from bio-coal can not be formed into pellets using self-bonding force unlike before bio-coal production, and thus the yield of pellet molding drops sharply.

6 shows PKS and bio-coal pellets according to Comparative Example 3 of the present invention. FIG. 6A shows PKS bio-coal produced from bio-coal at 200 ° C., FIG. 6B shows PKS bio- And shows the discharged shape when it is molded into pellets by using a pelletizing apparatus after manufacture. When the pellets were molded using the bio-coalized PKS, most of them were discharged in powder form through the pellet die or in a very shortened state, and the molding conditions were not very uniform.

7A and 7B are photographs of coal-fired EFB and bio-coal pellets according to Comparative Example 4 of the present invention. FIG. 7A shows EFB bio-coal produced from bio-coal at 200 ° C., FIG. And shows the discharged shape when molded into a pellet using a post-pelletizing apparatus. As in Comparative Example 3, Comparative Example 4 was discharged in the form of a powder through the die hole before the exothermic process by the pellet die. Since the bonding force between the EFB particles was very weak, .

8 is a photograph of PKS bio-coal and EFB bio-coal according to a preferred embodiment of the present invention. 8A and 8E show the biomass pellets of Comparative Examples 1 and 2 which were not subjected to the semi-carbonization process. As can be seen from FIGS. 8A and 8E, it was confirmed that the pelletization proceeded very easily. Figs. 8B to 8D show the bio-coal according to Examples 1 to 3, Figs. 8F to 8H show the bio-coal according to Examples 4 to 6, and the surface color of the pellet Dark brown to black brown, and finally black. That is, the degree of bio-coalification was easily judged by the surface color of the pellet alone. In addition, it was confirmed that the moldability was superior to that of Comparative Examples 3 and 4 which were pelletized after the coalification.

(2) Elemental change and industrial analysis

Table 1 and Table 2 show the elemental changes when pellets made of PKS and EFB were prepared from bio-coal at different temperatures as in Examples 1 to 6 and Comparative Examples 1 and 2. The composition of PKS and EFB varies depending on the conditions of oil palm biomass and palm oil production plant, such as ash, chlorine, sulfur and nitrogen. The PKS and EFB used in the present invention were obtained from a palm oil production plant in Indonesia and 0.1 to 0.5 wt% of sulfur was detected, which is much more than 0.05 wt%, which is specified in the quality characteristics of the wood pellets. In the case of nitrogen content, the content corresponding to the quality standard of the grade 1 to 4 grade pellets was found to be 0.2 to 0.7 wt%. However, according to the quality standard of Bio-SRF notified by the Ministry of Environment, 0.6% by weight or less of sulfur content satisfies the quality standard of Bio-SRF, so it can be sufficiently used as Bio-SRF. The chlorine content measured separately was 0.2% by weight in EFB and nearly 0.5% by weight in Bio-SRF. However, it did not satisfy the quality standard of the wood pellets of less than 0.05 wt%. As the temperature increased during the production of bio - coal, the content of sulfur was little changed, while the content of nitrogen increased slightly with increasing temperature during the production of bio - coal. It is presumed that the nitrogen component, which is an inert gas injected in the bio-coal production process, remains between the pores of the pellets, thereby affecting the increase of the nitrogen content. When PKS and EFB were made into bio-coal, pellets were prepared and the change in the content of nitrogen was not observed at all. In fact, since the process of making bio-coal with large capacity does not use nitrogen gas, it is expected that no problem of increase of nitrogen content due to increase in temperature during production of bio-coal is expected to occur.

In the case of ash content, the ash content starts to increase as the volatile matter evaporation or moisture content decreases as the bio-coalization progresses. When both PKS pellets and EFB pellets are bioconverted at 250-300 ° C., An increase in content occurred. The PKS pellets increased from 3.1 wt.% To 4.2 wt.%, And the EFB pellets increased from 5.8 wt.% To 8.8 wt.%, Increasing the ash content from 33 wt.% To 52 wt.% Before bioconcentration. The quality standard of wood pellets is allowed up to 6 wt% ash, so EFB pellets deviate from the quality standard of wood pellets due to bio-coalification, but bio ash content can be up to 15 wt% Both PKS pellets and EFB pellets can be used as high-efficiency Bio-SRF.

As bio - coalification progressed, both hydrogen and oxygen content decreased and relative oxygen content increased in both PKS and EFB pellets. Generally, in the case of bituminous coal or sub-bituminous coal, the carbon content reaches about 80% by weight. Even if it is made from bio-coal at a temperature of 300 ° C, the carbon content is only 66% by weight, but the carbon content due to bio- % ≪ / RTI > by weight. As a result, the bio-coalification technology is a very efficient fuel reforming technology that changes the lignocellulosic biomass into a bituminous coal.

division N (% by weight) S (% by weight) C (% by weight) H (wt%) O (% by weight) Ash (wt%) Comparative Example 1 0.2 0.1 49.4 6.4 40.8 3.1 Example 1 0.2 0.1 52.8 6 38.5 2.8 Example 2 0.3 0.1 55.2 5.8 35.1 3.6 Example 3 0.7 0.1 65.6 4.7 24.6 4.2

division N (% by weight) S (% by weight) C (% by weight) H (wt%) O (% by weight) Ash (wt%) Comparative Example 2 0.5 0.5 45.7 6.2 41.4 5.8 Example 4 0.5 0.3 46.9 6.1 42.1 4.2 Example 5 0.6 0.2 55.2 5.7 32.3 6 Example 6 0.8 0.2 66.3 4.5 19.4 8.8

FIG. 9 is a graph of the atomic ratio of carbon, hydrogen, and oxygen according to a preferred embodiment of the present invention, and is a molecular ratio curve of carbon, hydrogen, and oxygen on the Van Krevelen diagram. FIG. 9 shows changes in O / C and H / C of Examples 1 to 6 and Comparative Examples 1 and 2. The higher the temperature of the semi-carbonization, the closer to the bituminous coal, and the Example 6 in which the semi-carbonization process was performed at 300 ° C was closer to the bitterness of the bittern than the Example 3. This means that EFB pellets composed of fibrous form are more easily pyrolyzed than PKS pellets even if they are bio-coalized at the same temperature. As a result, when the PKS pellets and the EFB pellets are bio-coalized at atmospheric pressure, the thermal efficiency of the pellets can be improved to a very high level due to the properties of bituminous coal itself.

10 is a graph showing an industrial analysis result according to temperature according to a preferred embodiment of the present invention. In Examples 1 to 6 and Comparative Examples 1 and 2, as the temperature increases, the volatile matter decreases, whereas the fixed carbon increases as the temperature increases. The lignocellulosic biomass is composed of about 80% by weight of volatile matter and 20% by weight of fixed carbon. Generally, when the bio-coalization proceeds, 80 to 95% by weight of the energy is retained and only 70 to 90% by weight of the initial weight of the biomass is left. During the production of bio-coal, biomass is removed in a gaseous form in an initial weight of 10 to 30 wt%, which corresponds to moisture and volatile matter. The volatile matter removed at this time is a component containing most of the oxygen contained in the lignocellulosic biomass, and the combustion efficiency of the biomass is improved by removing these volatile components. PKS pellets and EFB pellets, as in Example 3 and Example 6, when the bio-coalization progressed at 300 ° C, the ratio of the fixed carbon was increased to about 60%, and the calorific value of these pellets also increased.

(3) Calorimetric measurement

11 is a graph showing calorific value of bio-coal according to a preferred embodiment of the present invention. The calorific values of PKS pellets and EFB pellets of Comparative Example 1 and Comparative Example 2 before production of bio-coal were respectively 19.4 MJ / kg (= 4,610.3 kcal / kg) and 18.0 MJ / kg (= 4,288.9 kcal / kg). However, as the bio-coalization progressed, the calorific value of the PKS pellets and the EFB pellets gradually increased. In Example 2, 21.7 MJ / kg (= 5,157 kcal / kg) and Example 4 was 21.8 MJ / kg (= 5,182.4 kg) Example 3 was improved to 25.9 MJ / kg (= 6,174 kcal / kg) and Example 5 was 25.4 MJ / kg (= 6,038 kcal / kg).

12 is a graph showing a heating rate increase rate of bio-coal according to a preferred embodiment of the present invention. As shown in FIG. 12, the PKS pellets and the EFB pellets were prepared in the same manner as in Example 1 and Example 4 were 7% and 3%, respectively, and 12% and 21% in Example 2 and Example 5 at 250 ° C and 33.9% and 40.8% in Example 3 and Example 6 at 300 ° C, respectively Respectively. The biomass properties of EFB pellets were more sensitive to the temperature during the production of bio - coal than the PKS pellets because of the biodegradability of the pellets. In conclusion, bioconcentration conditions must be applied to biomass because biodegradability of lignocellulosic biomass varies depending on the material properties of lignocellulosic biomass.

Experimental Example  2: Durability analysis

In order to measure the durability of the lignocellulosic bio-coal produced according to Examples 1 to 6 and Comparative Examples 1 to 4, 500 g of bio-coal pellets sieved with a diameter of 3.15 mm according to ISO 3310-2 was mixed with 0.01 g , And the resultant was placed in a durability tester based on the CEN / TS 15210-1 standard as shown in Fig. 5 and then subjected to 10 minutes at a speed of 50 rpm. Thereafter, the weight (g) of the bio pellet after sieving with a sieve having a diameter of 3.15 mm Respectively. Thereafter, durability was calculated according to the following relational expression (4).

[Relation 4]

(1) Evaluation of durability change

13 is a graph showing the durability of bio-coal according to a preferred embodiment of the present invention. The durability of PKS pellets and EFB pellets decreases rapidly depending on the temperature of the semi-carbonization. In particular, in Examples 3 and 6, the durability of PKS pellets and EFB pellets was reduced from 96% and 98% before bioconversion to 72-74% after half-carbonization. In addition, it was confirmed from the results of Examples 1 and 4 that the temperature of the semi-carbonization process is 200 ° C, that of Examples 2 and 5 that the temperature is 250 ° C, and that the durability decreases as the temperature increases. This means that when the biocharged PKS pellets and the EFB pellets are packed and transported, the shape of the pellets may be easily broken before the bio-coalization. In the bio-coalification process, the bonding force between the lignocellulosic biomass particles constituting the pellets is drastically weakened, so that the biomass particles constituting the bio-coalized pellets are separated in powder form or the pellets are easily shortened in length Lt; / RTI >

(2) Evaluation of pyrolysis characteristics

FIG. 14 is a graph of pyrolysis characteristics of bio-coal according to a preferred embodiment of the present invention. Both the KS pellet and the EFB pellet began to lose weight due to the removal of volatile components in the pellet after the water was removed as the temperature increased during the production of bio-coal. Instead of reducing the weight loss due to removal of volatiles, weight loss due to combustion of the fixed carbon began to take place. This tendency can be clearly observed in Examples 2 and 4 at a temperature of 250 ° C in the production of bio-coal, and in Examples 3 and 6 at a temperature of 300 ° C. As can be seen from the results of Examples 1 to 6, The weight loss due to the combustion of carbon was much higher. In Examples 1 and 4, which were prepared prior to production of bio-coal, the production of bio-coal at 200 < 0 > C was small because the amount of fixed carbon was small and it took a long time to remove volatile matter. It was confirmed that the weight loss was very small.

As a result, in order to increase the combustion efficiency of woody biomass, it is necessary to increase the amount of fixed carbon to increase weight loss due to combustion of fixed carbon, and it is important to manufacture pellets having high combustion efficiency through bio-coalization there was.

Experimental Example  3: mass yield, energy yield and energy density analysis

The mass yield, energy yield and energy density of the lignocellulosic bio-coal produced according to Examples 1 to 6 and Comparative Examples 1 to 4 were calculated according to the following relational formulas Respectively.

[Relation 1]

In the above relational expression 1, M _torrefaction represents the mass of the bio-coal after the semi-carbonization, and M _raw represents the mass of the bio-coal before the semi-carbonization.

[Relation 2]

In the above-mentioned relational expression 2, H _hv represents a high calorific value.

[Relation 3]

(1) Mass yield and energy yield measurement

15 is a graph showing a mass yield and an energy yield of bio-coal according to a preferred embodiment of the present invention. The mass yields of the PKS pellets and the EFB pellets when bio-coalized were as shown in Examples 1 and 4, which were 200 ° C. during the production of bio-coal, and about 90 ° C., % To 40 ~ 44%, while the energy yield decreased to about 56 ~ 62% at about 95%. The decrease in mass yield and energy yield during bio-coalition is primarily due to moisture evaporation, removal of volatile matter, and degradation of hemicellulose, and it should be noted that the temperature during the production of bio-coal greatly affects the mass yield and energy yield do.

(2) Measurement of energy density

16 is a graph of energy density of bio-coal according to a preferred embodiment of the present invention. PKS pellets and EFB pellets showed mass reduction to the level of 40-50% compared to the masses of Comparative Examples 1 and 2 which did not undergo semi-carbonization due to the progress of bio-coalization, and the energy was lower than that of Comparative Example 1 And 50% to 60% of the energy of Comparative Example 2, respectively. However, the energy density increased to 30 ~ 40% with bio - coalification, and it could be expected to improve in energy efficiency. However, in Examples 1 and 4 in which half-carbonization was carried out at 200 ° C, the energy density was improved to 10% or less. However, in Example 2, Example 3 and Example 5, In Example 6, an energy density improvement of 12 to 40% level occurred. In particular, in Examples 4 to 6 in which EFB pellets were semi-carbonized, it was found that the synergistic effect of the energy density was larger than in Examples 1 to 3 in which PKS pellets were semi-carbonized. In conclusion, it can be seen that in Examples 1 to 6 made from bio-coal than in Comparative Examples 1 and 2 before bio-coalification of PKS pellets and EFB pellets, higher energy efficiency can be obtained even when a small amount of pellets are burned have.

Claims (12)

Pelletizing the lignocellulosic biomass to produce a biomass pellet; And
Carbonizing the biomass pellet to produce bio-coal,
The semi-carbonization process is carried out at 200 ° C to 320 ° C under anaerobic and atmospheric pressure,
Wherein the lignocellulosic biomass comprises one or more selected from Empty fruit bunch (EFB) and Palm kernel shell (PKS). The method of claim 1, further comprising pretreating the lignocellulosic biomass prior to the step of preparing the biomass pellet. 3. The method of claim 2, wherein the pre-
When the lignocellulosic biomass is EFB,
Drying the EFB to a moisture content of less than 15%; And
And processing the length of the EFB to less than 60 mm. ≪ RTI ID = 0.0 > 11. < / RTI > 3. The method of claim 2, wherein the pre-
And pulverizing the lignocellulosic biomass to less than 70% of the initial volume when the lignocellulosic biomass is PKS. The method according to claim 1, wherein the step of preparing the biomass pellet is performed at 100 ° C to 170 ° C for 30 minutes to 90 minutes. The method of claim 1, wherein the semi-
The internal temperature is raised from 20 ° C to 25 ° C at a rate of 7 ° C to 13 ° C / min,
Wherein the inert gas is supplied at a rate of 0.03 to 0.07 L / min. The method according to claim 1, wherein the step of preparing the bio-coal is performed at 230 ° C to 320 ° C. The calorific value is 4,000 to 6,500 kcal / kg,
Semi-carbonized EFB (Empty fruit bunch) pellets or semi-carbonized PKS (Palm kernel shell) pellets,
In case of semi-carbonized EFB pellets, the mass yield according to the following formula 1 is 38 to 92%, the energy yield according to the following formula 2 is 58 to 97%
A semi-carbonized PKS pellet having a mass yield of 40 to 90% according to the following formula 1 and an energy yield of 51 to 96% according to the following formula 2: Lignocellulose-
[Relation 1]

In the above relational expression 1, M _torrefaction represents the mass of the bio-coal after the semi-carbonization, and M _raw represents the mass of the bio-coal before the semi-carbonization.
[Relation 2]

In the above-mentioned relational expression 2, H _hv represents a high calorific value. 9. The method of claim 8, wherein the bio-
In the case of semi-carbonized EFB pellets, the energy denity according to the following formula 3 is 1.03 to 1.42,
A semi-carbonized PKS pellet having an energy density of 1.06 to 1.34 according to the following relational expression (3): Ligno-cellulose-based bio-coal having improved calorific value.
[Relation 3]

9. The method of claim 8, wherein the bio-
In case of semi-carbonized EFB pellets, the durability according to the following formula 4 is 70 to 92%
In case of semi-carbonized PKS pellets, the lignocellulosic bio-coal having an improved calorific value is characterized in that the durability according to the following relational expression 4 is 60 to 85%
[Relation 4]

The durability is measured by weighing 500 g of bio-coal pellets sieved with a diameter of 3.15 mm according to ISO 3310-2 to 0.01 g, putting it into a durability tester based on CEN / TS 15210-1 regulation, Min, and the weight (g) of the bio-pellet after sieving with a sieve having a diameter of 3.15 mm was measured. The method of claim 8, wherein the semi-carbonized EFB pellets comprise 46 to 67.5 wt% carbon, 18.5 to 43 wt% oxygen, 4 to 6.15 wt% hydrogen, and balance nitrogen, sulfur,
Wherein the semi-carbonized PKS pellets comprise 51.5 to 67% by weight of carbon, 23 to 40% by weight of oxygen, 4.2 to 6.2% by weight of hydrogen, and residual nitrogen, sulfur and ash, Coal. The lignocellulosic bio-coal according to claim 8, wherein the bio-coal has a calorific value of 5,000 to 6,300 kcal / kg.

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