WO2012023479A1

WO2012023479A1 - Solid fuel, and method and apparatus for producing same

Info

Publication number: WO2012023479A1
Application number: PCT/JP2011/068324
Authority: WO
Inventors: 茂也林; 宏天野
Original assignee: 宇部興産株式会社
Priority date: 2010-08-17
Filing date: 2011-08-10
Publication date: 2012-02-23
Also published as: CN102959059B; JPWO2012023479A1; MY161924A; CN102959059A; JP5741585B2

Abstract

Disclosed is a solid fuel which contains, on air dried basis, 20-60% by mass of fixed carbon, 30-66% by mass of volatile content and 3-6% by mass of ash content, while containing 6% by mass or less of moisture content. The solid fuel has a higher calorific value of 20-30 MJ/kg on air dried basis. This solid fuel can be produced by a method for producing a solid fuel, said method comprising a supply step wherein shells left after obtaining kernel oil by oil-pressing palm fruit seeds are supplied to a heating means and a heating step wherein the shells are heated at a temperature of 240-350°C by the heating means, thereby obtaining a heat-treated solid of the shells.

Description

Solid fuel, method of manufacturing the same, and manufacturing apparatus

The present invention relates to a solid fuel obtained by heating biomass, a method for producing the same, and a production apparatus.

As one of the measures against global warming, using biomass as fuel derived from a living thing as an energy source is performed. For example, biomass is used as a partial fuel substitute for coal in a coal-fired power plant. In order to use biomass in a coal thermal power plant, pulverization of biomass is necessary to improve combustion efficiency. A coal-fired power plant has a coal crusher that crushes coal, so biomass is crushed together with coal by a coal crusher, and the pulverized biomass and pulverized coal are mixed and burned (co-fired).

In addition, biomass generally has a high porosity and thus has poor energy transportability, and has a high moisture content, so it has a low thermal energy density and a small calorific value when used as a fuel as it is. For this reason, the biomass is used by drying, crushing and pelletizing the biomass, and carbonizing the biomass. For example, Patent Document 1 describes a method of burning a biomass-based fuel in which carbonized biomass and coal are co-fired. Further, Patent Document 2 discloses the contents of compressing crushed coconut shell and using the coconut shell as a microbial base for garbage treatment instead of fuel.

JP, 2005-114261, A JP 2002-316128 A

However, comminution of biomass with a coal crusher is not easy, and the crushability is worse than that of coal, especially in the case of a shell (palm kernel shell) after the biomass has oiled nuclear oil from the seeds of a fruit of a coconut palm , Can not be finely pulverized.
The biomass carbide used in Patent Document 1 is carbonized at a high temperature of 400 to 500 ° C., and a large amount of energy is lost at the time of carbonization, and there is also the possibility of powderization during transportation and environmental pollution.
Moreover, although the point which compresses coconut shell is described in patent document 2, it does not describe using compressed coconut shell as biomass fuel.
An object of the present invention is to provide a solid fuel which uses palm kernel shell as biomass, is excellent in grindability, is high in calories, and does not generate dust, and a method for producing the solid fuel and its production apparatus.

As a result of various studies, the present inventors have found that low-temperature carbonization treatment of a palm kernel shell can provide a solid fuel that solves the above-mentioned problems.
The present invention was made based on the above findings, and is a solid fuel obtained by heating a shell after squeezing a kernel oil from a seed of a fruit of a coconut, wherein the solid carbon is 20 to 60 on an air-dried basis. To provide a solid fuel containing 30% to 66% by mass of volatile matter, 3 to 6% by mass of ash, 6% by mass or less of water, and having a high calorific value of 20 to 30 MJ / kg on an air-dry basis It is.
In the above solid fuel, assuming that the molar ratio of hydrogen H to carbon C is H / C and the molar ratio of oxygen O to carbon C is O / C, then 0.65 <H / C <1. It is intended to provide a solid fuel wherein 1 and 0.15 <O / C <0.5.
Further, the present invention provides a method for producing the solid fuel, the step of supplying shells to a heating means after squeezing a kernel oil from seeds of a fruit of an eggplant, and heating the shells in the heating means The present invention provides a method for producing a solid fuel, comprising the steps of: heating to obtain a fuel; and setting the heating temperature in the heating to 240 to 350 ° C.
The present invention is also an apparatus for producing a solid fuel, wherein solid fuel is obtained from shells after squeezing nuclear oil from seeds of a fruit of an eggplant, and the heating means for heating the shells to obtain the solid fuel, and It is an object of the present invention to provide a solid fuel manufacturing apparatus characterized in that the heating means is provided with a feeding means for feeding the shell, and the heating temperature in the heating means is 240 to 350 ° C.

According to the present invention, it is possible to obtain a solid fuel which uses palm kernel shell as biomass, is easy to be crushed, has a small amount of crushing energy and is high in calories. In addition, since there is no dust generation property, solid fuel can be obtained which is safe and does not cause environmental pollution.
Although it is out of the scope of the present invention, a palm kernel shell may be pressure-compressed and flattened to be used as a fuel as a reference example.

It is a graph which shows the relationship between the heat processing temperature shown in Table 2, and HGI equivalent number. It is a graph which shows the FT-IR analysis result of the heat processing solid of PKS. It is a graph which shows the FT-IR analysis result of the heat processing solid of wood waste. It is a graph which shows the relationship between the WI equivalent number of heat processing solid of PKS and wood waste and the heat processing temperature. It is a graph which shows the result of a pulverization test of heat processing solid of PKS and wood chips. It is a graph which shows the particle diameter of PKS, and the relationship of under-sieve integration. It is a figure which shows the comparison of the elemental composition ratio of various raw materials. It is a graph which shows the change of the heat processing temperature of PKS and wood waste, and the value of H / C and O / C. It is a graph which shows thermogravimetric analysis of PKS and wood waste in the air, and coal. _{_{O 2: 4%, N 2}} : PKS and wood chips in a 96% and is a graph showing the thermogravimetric analysis of coal. It is a graph which shows the underwater immersion test result of PKS. It is a graph which shows the underwater immersion test result of wood chips. FIG. 13 (a) is a 30 × SEM picture of the fractured surface of PKS before heating, FIG. 13 (b) is a SEM picture of 200 × of the fractured surface of PKS before heating, and FIG. 13 (c) It is a 1000 times SEM photograph of the fractured surface of PKS before heating. FIG. 14 (a) is a 30 × SEM picture of the fractured surface of PKS heat-treated at 300 ° C. FIG. 14 (b) is a 200 × SEM photograph of the fractured surface of PKS heat-treated at 300 ° C. FIG. 14 (c) is a SEM photograph at 1000 times the fracture surface of PKS heat-treated at 300 ° C.

The solid fuel of the present invention will be described based on its preferred production method.
The “shell after oiling a kernel oil from seeds of a fruit of a coconut palm” used as biomass in the present invention is referred to as palm kernel shell (hereinafter sometimes abbreviated as PKS).
The PKS preferably has a water content of 40% by mass or less, and more preferably a water content of 15% by mass or less.

The heat treatment of the PKS is carried out at a temperature of 220 to 400 ° C., preferably 240 to 350 ° C., more preferably 296 to 350 ° C., particularly preferably 300 to 300 ° C. in a state where supply of air is restricted or shut off or an inert gas atmosphere. It is a so-called low temperature carbonization treatment performed at a temperature of 330 ° C. Here, the temperature referred to in the present invention means the temperature of the heat-treated solid. In addition, low temperature carbonization refers to thermal decomposition of an organic solid performed in a reducing atmosphere at 400 ° C. or less. Furthermore, the reducing atmosphere refers to a state in which the supply of air is restricted or shut off or an inert gas atmosphere. The oxygen concentration in the reducing atmosphere (heat treatment atmosphere) is preferably 5% by volume or less.
When the temperature of the heat treatment is less than 220 ° C., the crushability is improved as compared to the case where low temperature carbonization is not performed. When the temperature of the heat treatment exceeds 350 ° C., the solid yield after the heat treatment is small, and the energy loss at the heat treatment tends to be large. When the temperature is 296 ° C. or more, the crushability is significantly improved.
The heating device used for the heat treatment may be a heating device conventionally used for carbonization treatment of biomass, and may be an internal heating type, an external heating type, a batch type or a continuous type. Specifically, for example, an internal heating rotary kiln, an external heating rotary kiln, a moving bed heating apparatus, a packed bed heating apparatus and the like can be mentioned.

The temperature raising rate is not particularly limited, but it is usually from 1 to 10 ° C./minute, preferably from 1 to 5 ° C./minute, from the ambient temperature to the desired heating temperature.
The heat treatment time is preferably within 90 minutes, more preferably within 50 minutes, after reaching a temperature of 220 to 400 ° C. If the heat treatment time is too long, the solid yield after heat treatment decreases and the heat energy recovery rate to solid decreases, so the temperature rise rate and heat treatment time are appropriately determined according to the desired properties of the solid fuel. Do.

By the heat treatment of the PKS, the solid fuel of the present invention as a heat-treated solid and the first gas as a gas component are obtained.
The first gas contains tar and volatile matter. Therefore, also from the viewpoint of suppression of energy loss, after the first gas is discharged from the heating device, the first gas is supplied to the combustion device to burn tar and volatile matter in the first gas, and After obtaining the second gas, it is preferable to return the second gas to the heating device and recover it as part of the energy for the heat treatment of the PKS. The combustion temperature of the first gas in the combustion apparatus is preferably 500 to 1,200 ° C., more preferably 850 to 1,000 ° C.
The combustion apparatus for burning the first gas is not particularly limited as long as it can burn tar or volatile matter in the first gas, and it is usually a refractory-lined gas combustion furnace or the like. The first gas may be burned together with the solid fuel of the present invention by the “heat utilization facility using the solid fuel of the present invention” described later. The first gas can also be cooled to separate the tar.

The properties of the solid fuel of the present invention obtained by the above-described PKS heat treatment will be described. The fixed carbon of the solid fuel is 25 to 60% by mass, preferably 35 to 60% by mass, more preferably 45 to 55% by mass on an air-dry basis. Further, the volatile content is 30 to 66% by mass, preferably 35 to 55% by mass, more preferably 35 to 45% by mass on an air-dry basis. Furthermore, the ash content is 3 to 6% by mass, preferably 3 to 5% by mass on an air-dry basis. In addition, the water content is 6% by mass or less, preferably 5% by mass or less. Furthermore, the higher calorific value is 20 to 30 MJ / kg, preferably 24 to 30 MJ / kg, more preferably 25 to 30 MJ / kg on an air-dried basis. Here, the air-dried base means a solid weight measured by the air-dried sample preparation method described in Japanese Industrial Standard JIS M 8811. Further, the method of measuring the fixed carbon, volatile matter, ash and water of the solid fuel according to the present invention was based on the method described in Japanese Industrial Standard JIS M8812. Furthermore, the high-order calorific value refers to the total calorific value, and the measurement method was according to the method described in Japanese Industrial Standard JIS M8814. The volatile matter contained in the solid fuel is partially aromatic or the like.

The solid fuel of the present invention is substantially equivalent to the particle size of raw PKS by the above-mentioned heat treatment of PKS, and is not pulverized. Therefore, when transporting solid fuel after low temperature carbonization, there is no contamination around the area due to dusting. The average particle size of raw PKS is usually about 5 mm, and the average particle size of the solid fuel of the present invention is also about 5 mm. Here, the average particle diameter referred to in the present invention means a median diameter, and can be obtained by the particle size test method described in JIS M8801.

The solid fuel obtained by the heat treatment of the present invention has improved crushability compared to that before the heat treatment. The WI equivalent number of the solid fuel obtained by the present invention is 0.7 to 2.5. In the case of common fuel coals measured for comparison, the solid fuel is evaluated as having the same degree of grindability as coal because the WI equivalent number is 1.0 to 2.0. Here, the WI equivalent number refers to a relative evaluation of the grindability, and can be obtained by measurement of an initial grinding rate using a ball mill. It indicates that the smaller the value of the WI equivalent number, the easier the pulverization (described later).
In addition, the solid fuel obtained in the present invention has a HGI equivalent number of 16 to 25, is a solid maintaining an appropriate hardness, and has no dusting property. Here, the HGI equivalent number refers to the grindability index obtained by the measurement method similar to HGI described in JIS M8801, and is determined by the degree of grinding at a constant rotation number using a ball mill. The larger the value of the HGI equivalent number, the easier the pulverization is shown (described later).
In the present invention, the equivalent WI number is 2.5 or less, and the equivalent HGI number is preferably 15 or more, particularly preferably 16 or more, from the viewpoint of the required power for pulverizing solid fuel. The details of the evaluation method of the WI equivalent number and the HGI equivalent number will be described in more detail in the following examples.

The solid fuel of the present invention is used as an energy source of heat utilization equipment by supplying it to the heat utilization equipment and burning it. In particular, the solid fuel of the present invention is preferably supplied to a heat utilization facility and burned as a partial replacement fuel for coal.
The heat utilization equipment in which the solid fuel of the present invention is used is not limited, and the existing heat utilization equipment can be used, for example, pulverized coal firing boiler, rotary kiln of cement clinker production equipment, cement clinker A calcining furnace for manufacturing equipment, a coke furnace for iron making equipment, a blast furnace, etc. may be mentioned, and among them, a pulverized coal burning boiler, a rotary kiln for cement clinker manufacturing equipment, a calcining furnace and the like are preferable.

The solid fuel of the present invention may be pulverized and then supplied to the heat utilization facility from the viewpoint of improving combustion efficiency and the like. The degree of this pulverization depends on the heat utilization equipment to which the solid fuel is supplied, but usually, it is preferable to pulverize so that the average particle diameter is 1,000 μm or less, and pulverize so that the average particle diameter is 750 μm or less Is more preferable.
The solid fuel of the present invention has excellent crushability and can be easily crushed by a vertical roller mill, a tube mill, a hammer mill, a fan type mill, etc., and is also provided in a coal-fired power plant. Can be easily pulverized with the coal. Also, solid fuel can be supplied to a heat utilization facility with coal and burned.

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited at all by these examples and comparative examples.

[Measurement of WI equivalent number of solid fuel]
The WI equivalent number is a value proportional to the pulverizing power per unit weight of the solid fuel, and the smaller this value is, the smaller the pulverizing power is. The measurement method of WI equivalent number is as follows.
Among solids, a 4.75 mm sieve was used as a sample for measurement of equivalent number of WI. This sample of 480 g comprises 43 steel balls having a diameter of 36.5 mm, 67 steel balls having a diameter of 30.2 mm, 10 steel balls having a diameter of 25.4 mm, 71 steel balls having a diameter of 19.1 mm, and a diameter of 15 In a ball mill containing 94 9 mm steel balls, it is ground at a rotation speed of 70 revolutions per minute for 1 minute, 2 minutes, 4 minutes, 10 minutes, and each milled using a standard sieve with an opening of 150 μm. The weight under the sieve in time was measured, and the mass fraction was calculated. Next, the relationship between the mass fraction determined above and the grinding time is plotted in the figure, the grinding rate constant kxc (min ⁻¹ ) is determined from the slope, and the WI equivalent number is determined by the following equation.
Equivalent number of WI = Xc ^0.5 · (kxc · Ws) ^-0.82
Xc: Standard sieve opening = 150 (μm)
kxc: Grinding rate constant (min ^-1 )
Ws: 480 (g)

[Measurement of HGI equivalent number of solid fuel]
The HGI equivalent number of solid fuel is measured by the following method. The HGI equivalent number is a numerical value for evaluating the grinding ability of solid fuel, and the larger the numerical value, the better the grinding property. The measurement method of the HGI equivalent number is as follows.
The solid was crushed by a cutter mill, and a sample under a 1,000 μm sieve was used as a sample for measuring HGI equivalent number on a 500 μm sieve. A ball mill containing 50 g of this sample for measurement of 50 g of steel balls with a diameter of 25.4 mm was operated at a speed of 15 to 20 revolutions per minute at 60 revolutions, and the ground sample obtained was sieved using a 75 μm sieve. The sample weight (wg) was measured. Using the numerical value w obtained in this manner, the HGI equivalent number was determined by the following equation.
HGI equivalent number = 13 + 6.93 x w
w: weight under 75 μm sieve (g)

[Solid yield after heat treatment]
The solid yield after the heat treatment was determined by the following equation.
Y = W1 × (1−h1 / 100) / {W0 × (1−h0 / 100)} × 100
Y: solid yield (mass%)
W1: Solid weight after heat treatment (g)
h1: Moisture content of solid after heat treatment (mass%)
W0: Solid weight before heat treatment (g)
h0: Moisture content of solid before heat treatment (mass%)

[High-order calorific value of sample]
The high calorific value was determined according to JIS M8814.

[Calculation of energy fixation rate]
The energy immobilization rate was calculated from the solid yield after the heat treatment and the high calorific value of the sample before and after the heat treatment. The larger the value, the larger the energy available as the heat-treated solid. The energy fixation rate was determined by the following equation. In the present invention, from the viewpoint of effective use of energy, the energy fixation rate is considered to be within the allowable range of 65% or more.
Ye = H1 × W1 × (1−h1 / 100) / {H0 × W0 × (1−h0 / 100)} × 100
Ye: Energy fixation rate (%)
H1: Solid high-order calorific value (MJ / kg) after heat treatment
W1: Solid weight after heat treatment (g)
h1: Moisture content of solid after heat treatment (mass%)
H0: Solid high-order calorific value (MJ / kg) before heat treatment
W0: Solid weight before heat treatment (g)
h0: Moisture content of solid before heat treatment (mass%)

Example 1
Shells (PKS) were used after oil extraction of the kernel oil from the seeds of oil palm fruits. The PKS used is a shell of Indonesian oil palm, and the elemental composition is as follows.
Carbon (% on anhydrous basis) 52.1
Hydrogen (% on anhydrous basis) 4.8
Nitrogen (% anhydrous basis) 0.4
Total sulfur (% on anhydrous basis) 0.03
Chlorine (% anhydrous basis) 0.007
The industrial analysis values are as follows.
Moisture (air dry basis%) 9.0
Ash (air dry basis%) 2.4
Volatile matter (air-dry basis%) 70.7
Fixed carbon (air dry basis%) 17.9
The HGI equivalent number is 14, and the WI equivalent number is 11.

The PKS was dried on the sun to a moisture content of 12% by mass, and used was one having a particle size of 1 to 16 mm and an average particle size of 5 mm.
4 kg of the PKS is placed in a sample case with an inner diameter of 600 mm and a length of 500 mm, and the sample case is attached to an external heating rotary kiln to raise temperature from ambient temperature to 320 ° C. while circulating nitrogen gas as inert gas. Heated at 2 ° C./min. The reference heating temperature was the temperature of the gas phase atmosphere at the center of the axial center of the sample case. In the rotary kiln, the temperature of the gas phase atmosphere is the same as the temperature of the heat-treated solid. After the heating temperature reached 320 ° C., the temperature was maintained at 320 ° C. for 1 minute, and then it was rapidly cooled to 160 ° C. After that, the sample case was taken out of the rotary kiln and the sample was taken out to the air and allowed to cool to room temperature . Thus, a solid fuel as a heat-treated solid and a first gas were produced. The first gas produced together with the solid fuel was continuously supplied to the combustion apparatus and burned during the heat treatment of PKS to obtain a second gas.
The chemical composition, the average particle size, the higher calorific value, the HGI equivalent number, the WI equivalent number, the solid yield, and the energy immobilization rate of solid fuel are shown in Table 1. Table 1 also shows the moisture content and average particle size of PKS and the heat treatment conditions (heat treatment temperature and heat treatment time) of PKS. Table 1 also shows the physical properties of raw PKS (non-heat-treated solid) before heat treatment. The HGI equivalent number is 24, which is much larger than the raw PKS. In addition, the equivalent number of WI was 0.1 times or less of that of raw PKS, and the crushability was improved. In addition, the particle size distribution of the heat-treated solid was almost the same as that of the raw PKS, and the low temperature carbonization did not powder the solid particles.

Example 2
The same procedure as in Example 1 was carried out except that the heat treatment temperature of PKS was changed to 240 ° C. in Example 1, and a solid fuel as a heat-treated solid and a first gas were produced.
The chemical composition of solid fuel, average particle size, higher calorific value, equivalent number of HGI, equivalent number of WI, moisture content and average particle size of PKS, and heat treatment condition of PKS are shown in Table 1. The HGI equivalent number is 16 and is larger than the raw PKS. The equivalent number of WI was about 0.2 times that of raw PKS, and the crushability was improved. In addition, the particle size distribution of the heat-treated solid was almost the same as that of the raw PKS, and the low temperature carbonization did not powder the solid particles.

[Example 3]
The same procedure as in Example 1 was carried out except that the heat treatment temperature of PKS was changed to 350 ° C. in Example 1, to produce a solid fuel as a heat-treated solid and a first gas.
The chemical composition of solid fuel, average particle size, higher calorific value, equivalent number of HGI, equivalent number of WI, moisture content and average particle size of PKS, and heat treatment condition of PKS are shown in Table 1. The HGI equivalent number was 23 and significantly increased from the raw PKS. Furthermore, the WI equivalent number was about 0.1 times that of raw PKS, and the crushability was improved. In addition, the particle size distribution of the heat-treated solid was almost the same as that of the raw PKS, and the low temperature carbonization did not powder the solid particles.

[Reference Example 1]
The same procedure as in Example 1 was carried out except that the heat treatment temperature of PKS in Example 1 was 220 ° C., and a solid fuel as a heat-treated solid and a first gas were produced.
The average particle size of the solid fuel, the HGI equivalent number, the water content and average particle size of PKS, and the heat treatment conditions of PKS are shown in Table 1. The HGI equivalent number was 15, and the crushability was slightly improved as compared to the raw PKS. In addition, the WI equivalent number was about 3 times that of coal, and the crushability was slightly improved.

Reference Example 2
The same procedure as in Example 1 was carried out except that the heat treatment temperature of PKS was set to 400 ° C. in Example 1, to produce a solid fuel as a heat-treated solid and a first gas.
The chemical composition of solid fuel, average particle size, higher calorific value, equivalent number of HGI, equivalent number of WI, moisture content and average particle size of PKS, and heat treatment condition of PKS are shown in Table 1. The grindability was improved for both the HGI equivalent number and the WI equivalent number. However, the energy fixation rate dropped to about 60%.

[Detailed evaluation of grindability by HGI]
Based on the above results, the heating temperature and the crushability were examined in more detail.
[Examples 6 to 16]
The heat treatment was performed in the same manner as in Example 1 except that the heat treatment temperature was changed as shown in Table 2. The results are shown in Table 2 and FIG. It was revealed that the heat treatment temperature increased from 296 ° C. to the equivalent number of HGI, and the heat treatment equivalent number rapidly increased at 300 ° C. or higher. This means that the crushability is significantly improved. In addition, the particles of solid fuel were not pulverized.

Furthermore, the following various tests were conducted to determine the properties of the heat-treated solid of PKS. In various tests, the same PKS as used in Example 1 was used as PKS. The heat treatment of PKS or wood waste was carried out in the same manner as in Example 1 except the heating temperature, unless otherwise indicated.

[Correlation between residual amount of cellulose or lignin and properties of heat-treated solid]
(Correlation with residual cellulose)
A comparison was made between PKS and wood treated with heat-treated wood (Japanese cypress). As a heat processing solid, what was heated at 240 ° C, 260 ° C, and 300 ° C was used. FIGS. 2 and 3 show the results of FT-IR analysis of the heat-treated solid (manufactured by DigiLab, model number: FTS-7000e, single reflection method (using diamond)). FIG. 2 shows the case of PKS and FIG. 3 shows the case of wood waste. FIG. 4 is a diagram showing the relationship between the equivalent number of WI and the heat treatment temperature of the heat-treated solid.
Table 3 shows the weight composition of raw PKS before heating, cellulose in raw wood waste (Japanese cypress) and lignin. It can be seen from Table 3 that raw PKS has a high proportion of lignin and a low proportion of cellulose (including hemicellulose) as compared to raw wood waste. Hemicellulose is a fibrous substance which connects celluloses.

Lignin while having O-CH ₃ bond (2850 cm around ^-1), and C = C bond (1600 cm around ^-1), cellulose does not have the two types of bonds. On the other hand, since the OH bond (around 3400 cm ^-1 ) is mainly a bond possessed by cellulose, the degree of degradation of lignin and cellulose should be inferred by comparing the amounts of the above three types of bonds before and after heating. Is possible.

As is clear from FIG. 2, in the heat-treated solid of PKS, the O—CH ₃ bond and the C = C bond both decrease by heating but remain without being completely decomposed. Also, as is clear from FIG. 3, CCC bonds are hardly reduced in the heat-treated solid of wood waste. Therefore, it is surmised that lignin remains even after heating at least 240 ° C. to 300 ° C. for both PKS and wood waste.

On the other hand, for OH bond, PKS is greatly reduced by heating at least 240 ° C as shown in FIG. 2, but as is clear from FIG. 3, wood waste is also reduced significantly by 300 ° C. Not. Therefore, when PKS and wood waste are heated at 240 ° C to 300 ° C, it is assumed that while lignin remains while both cellulose in raw PKS is largely decomposed, cellulose in raw wood waste is hardly decomposed. .

As a result, the heat-treated solid of PKS having a relatively small amount of residual cellulose is superior in grindability to the heat-treated solid of wood waste having a large amount of residual cellulose. It can also be seen from FIG. 4 that the heat-treated solid of PKS has a relatively lower WI equivalent number than that of the heat-treated solid of wood chips, with the exception of a part of the heat-treated solid.

(Correlation with lignin residue)
The strength of raw PKS, raw wood waste is maintained by cellulose and lignin bonding cellulose to each other. Here, if the residual amount of lignin after heating is large, even if the cellulose is decomposed by heating, the strength of the heat-treated solid is maintained by the remaining lignin, so the strength of the heat-treated solid is greatly reduced. Absent.

As apparent from Table 3 above, raw PKS contains a large proportion of lignin as compared to raw wood waste, so that even in the heat-treated solid, PKS has relatively more residual lignin compared to wood waste. Therefore, the heat-treated solid of PKS is relatively strong compared to the heat-treated solid of wood waste, and is less likely to be pulverized during transportation.

FIG. 5 shows the powdering test results of heat-treated solids of PKS and wood waste. The powdering test was carried out by putting 1 kg or more of wood waste and PKS samples of 1 mm or more in a polyethylene bag, dropping 10 kg from a height of 3.1 m, and then measuring the ratio of 1 mm undersize particles. From FIG. 5, it is judged that the heat-treated solid of PKS has less particles of 1 mm or less compared to the heat-treated solid of wood waste at the same temperature, and is hard to be pulverized. Therefore, the heat-treated solid of PKS having a relatively large amount of residual lignin compared to the heat-treated solid of wood waste is less likely to be pulverized during transportation, and is excellent in the handling property.

FIG. 6 is a graph showing the relationship between the particle size of PKS and the undersize integration. In FIG. 6, the raw PKS, the graph of carbonized goods in each temperature of 290 degreeC, 300 degreeC, 310 degreeC, 320 degreeC, and 330 degreeC is shown. None of the 290.degree. C. to 330.degree. C. carbonized products has a large difference from the raw PKS, indicating that the dusting property is small.

(Comparison between PKS heat-treated solid and coal)
Table 4 shows the results of elemental analysis and industrial analysis of various raw materials. FIG. 7 is a comparison of elemental composition ratios of various raw materials based on Table 4 (ratio of hydrogen H to carbon C = H / C, oxygen O to carbon C) It is a figure which shows ratio = O / C. Both cellulose and hemicellulose have high H / C and O / C values, and both lignin is low. In addition, coal has smaller H / C and O / C values than lignin (see FIG. 7).

Since C of PKS heat-treated solid increases and H and O both decrease as the heating temperature rises, the values of H / C and O / C also decrease as the heating temperature increases. As apparent from Table 4, the heat-treated solid heated with raw PKS at 240 to 280 ° C. decreased in H / C and O / C values and was close to the lignin H / C and O / C values. . On the other hand, the values of H / C and O / C in the woods 240 ° C. and 260 ° C. heat-treated solid did not decrease as much as those of PKS. This is because in PKS, heating causes decomposition of cellulose to increase the proportion of lignin remaining in the heat-treated solid, while wood waste initially contains less lignin in the raw material (raw wood waste), and the amount of remaining lignin is also PKS It is guessed that it is lower than it is.

Also, the H / C and O / C values of PKS heat-treated solid at 300 to 320 ° C. both decrease further than the lignin H / C and O / C values, and coal H / C and O / C Close to the value of. Furthermore, volatiles, fixed carbon, and higher calorific value values in industrial analysis were also close to coal, and PKS heat-treated solid at 300 to 320 ° C. became a fuel close to coal. On the other hand, the values of H / C and O / C in the 300 ° C. heat-treated solid of wood waste were only about the same value as the 240-280 ° C. heat-treated solid of PKS. The carbon content in elemental analysis was also higher in PKS when compared at the same 300 ° C. heat-treated solid. Therefore, when heated at the same temperature, PKS is closer to coal than wood waste and has good characteristics as a fuel.

Moreover, FIG. 8 is a graph which shows the change of the heat processing temperature of PKS and wood chips, and the value of H / C, O / C. The values of H / C and O / C in the PKS heat-treated solid are substantially the same at 240 to 280 ° C., but decrease sharply at 280 to 300 ° C. and do not change significantly at 300 ° C. to 320 ° C. thereafter. Similarly, in FIG. 7, the heat-treated solid at 240 ° C. to 280 ° C. for PKS exhibits almost the same H / C and O / C values (region D1), but when the heating temperature rises from 280 ° C. to 300 ° C. The values of / C and O / C sharply decrease and become approximately the same at 300 ° C. and 320 ° C. (region D2).

Further, as apparent from Table 2, the heat-treated solid of PKS at 300 to 320 ° C. (corresponding to area D2 in FIG. 7) is compared to the heat-treated solid at 240 to 280 ° C. (corresponding to area D1 in FIG. 7). The HGI equivalent number has improved. When the relative positions of the regions D1 and D2 in FIG. 7 are compared, the region D1 is close to cellulose and hemicellulose, and the region D2 is close to coal. Therefore, it is surmised that PKS becomes closer to coal by heat treatment at 300 to 320 ° C., and the grindability is improved.

As described above, by heating PKS at around 300 ° C., the values of H / C and O / C of the heat-treated solid transit from the region D1 to the region D2. Therefore, by heating raw PKS at 300 to 320 ° C., it is possible to obtain a fuel having properties closer to coal.

FIGS. 9 and 10 show thermogravimetric analysis of PKS, wood waste, and coal (both at a heating rate of 10 ° C./min). FIG. 9 shows a graph in air, FIG. 10 in O ₂ : 4%, N ₂ : 96% gas (FIG. 10 on an anhydrous basis). In both of FIG. 9 and FIG. 10, it was confirmed that the PKS semi-carbonized product is closer to coal than the wood chip semi-carbonized product and has good combustion characteristics.

[Correlation of residual lignin and equilibrium water]
(Immersion test in water)
FIG. 11 is a graph showing the results of underwater immersion test of PKS, and FIG. 12 is a graph showing the results of underwater immersion test of wood waste. The immersion test in water was conducted by immersing 100 g of a sample in 1 liter of water at room temperature and measuring the change with time of solid moisture. As is clear from FIGS. 11 and 12, PKS had lower equilibrium water content than wood waste for both the raw material and the heat-treated solid, and was hard to absorb water. Therefore, since the moisture absorbed during storage is also low, PKS has a high amount of heat per unit weight and is excellent in handleability as compared to wood waste.

As described above, it is presumed that PKS contains more lignin in the raw material than wood waste, and there is more residual lignin even after heating. In addition, lignin adheres cellulose to each other and fills the void existing between the cellulose. Therefore, in PKS having a relatively large amount of lignin, there are relatively few voids between celluloses as compared to wood waste. As a result, since the moisture entering between the celluloses decreases when immersed in water, it is presumed that PKS has less equilibrium moisture than wood waste.

(Photograph of the fracture surface)
FIGS. 13 (a) to (c) and FIGS. 14 (a) to (c) are SEM photographs of fractured surfaces of PKS. FIG. 13 shows a broken surface of raw PKS before heating, and FIG. 14 shows a broken surface of PKS heat-treated solid after heating at 300 ° C. Although cell walls (the main constituent is cellulose) are confirmed as irregularities of a substantially hexagonal shape on the fracture surface of the raw material before heating, irregularities like the raw material before heating can not be confirmed on the fracture surface of the heat-treated solid at 300 ° C. The fractured surface was smooth and uniform. It is presumed that this is because the heat-treated solid has a homogeneous structure mainly composed of lignin as a result of decomposition of cellulose by heating.

[Effect of the embodiment]
(1) It is a solid fuel obtained by heating a shell after squeezing a nuclear oil from seeds of a fruit of an eggplant,
Containing 20 to 60% by mass of fixed carbon, 30 to 66% by mass of volatile matter, 3 to 6% by mass of ash, containing up to 6% by mass of moisture, and having a high calorific value of 20 to 30 MJ It was assumed to be / kg.
As a result, fuel close to coal can be obtained in terms of fuel properties such as volatile component and fixed carbon and grindability.

(2) In the solid fuel described in (1) above,
Assuming that the molar ratio of hydrogen H to carbon C is H / C and the molar ratio of oxygen O to carbon C is O / C, 0.65 <H / C <1.1, 0.15 <O It was decided that / C <0.5. As a result, the cellulose is decomposed while leaving lignin, the fiber quality is reduced while maintaining the strength of the PKS heat-treated solid, and the handling is improved by reducing the pulverization during transportation, and the crushability is excellent. Solid fuel can be obtained. It is more preferable if 0.7 <H / C <0.8 and 0.2 <O / C <0.3.

(3) The method for producing a solid fuel according to (1) or (2), wherein the shell is supplied to a heating unit, and the shell is heated in the heating unit to obtain the solid fuel. And a heating step, and the heating temperature in the heating step is set to 240 to 350.degree. This makes it possible to accelerate the decomposition of cellulose while leaving lignin. Therefore, while maintaining the strength of the PKS heat-treated solid and reducing the fiber quality to reduce the pulverization at the time of transportation, it is possible to improve the handling and obtain a solid fuel having excellent grindability.

(4) In the above (3), the heating temperature in the heating step is set to 300 to 330 ° C. This makes it possible to obtain fuel closer to coal.

In the present specification, PKS is heated at 240 ° C. to 350 ° C. to obtain a fuel, but heating may be performed if it is suitable as a fuel. For example, PKS may be pressure-compressed to form a flat plate having a thickness of several mm or less. This makes it possible to obtain a biomass-blended fuel that can be mixed and pulverized with coal and has good combustibility.

Claims

It is a solid fuel obtained by heating shells after squeezing a nuclear oil from the seeds of the fruit of a coconut palm,
Containing 20 to 60% by mass of fixed carbon, 30 to 66% by mass of volatile matter, 3 to 6% by mass of ash, containing up to 6% by mass of moisture, and having a high calorific value of 20 to 30 MJ Solid fuel which is / kg.
Assuming that the molar ratio of hydrogen H to carbon C is H / C and the molar ratio of oxygen O to carbon C is O / C,
0.65 <H / C <1.1
0.15 <O / C <0.5
The solid fuel according to claim 1.
The method for producing a solid fuel according to claim 1 or 2, wherein
Supplying the heating means with a shell after squeezing out the nuclear oil from the seeds of the fruit of the eggplant;
Heating the shell in the heating means to obtain the solid fuel;
The heating temperature in the heating step is set to 240 to 350 ° C.
The method for producing a solid fuel according to claim 3, wherein a heating temperature in the heating step is set to 300 to 330 ° C.
What is claimed is: 1. A solid fuel production apparatus for obtaining solid fuel from husks after oil extraction of nuclear oil from fruit seeds of a coconut palm,
Heating means for heating the shell to obtain the solid fuel;
Supply means for supplying the shell to the heating means;
The heating temperature in the heating means is 240 to 350 ° C., and the apparatus for manufacturing a solid fuel.