KR20100022948A

KR20100022948A - Method to make solid fuel of rice straw

Info

Publication number: KR20100022948A
Application number: KR1020090116357A
Authority: KR
Inventors: 오도건
Original assignee: 주식회사 유니바이오
Priority date: 2009-11-30
Filing date: 2009-11-30
Publication date: 2010-03-03
Also published as: KR101160738B1

Abstract

PURPOSE: A method for manufacturing a solid fuel using rice straw is provided to manufacture a solid fuel of high quality in which an apparent density is more than 500kg/m^3 and a generation amount of fine powder is less than 2.0% by using a suitable molding condition for a property of the rice straw. CONSTITUTION: A method for manufacturing solid fuel using rice straw is for improving a calorific value and reducing ash which the rice straw contains and chlorine and nitrogen content. The mixture is heated in a reaction bath at 25~100°C while stirred with 50~300rpm speeds after adding the rice straw pulverized to 0.5~5.0mm to the 5~30 times distilled water of the rice straw weight in which 1~10% of one specie selected from acetic acid and anhydrous citric acid or 1~10% of a mixture of acetic acid and anhydrous citric acid is added.

Description

Method of making solid fuel using rice straw {Method to make solid fuel of rice straw}

The present invention relates to a method for producing a solid fuel using rice straw, and more specifically, the straw is contained using an aqueous solution of hydrofluoric acid, acetic acid, anhydrous citric acid, and the like. The rice straw pretreatment method reduces the ash content and improves the calorific value, and primarily reduces the straw-containing harmful substances such as chlorine and nitrogen, and the activated carbon is used as the adsorbent during the acid treatment or after the acid treatment. It consists of rice straw-containing chlorine, a method of secondly reducing nitrogen content, and a molding method of molding rice straw into a certain form.

Conventional methods for preparing solid fuel using rice straw include the carbonaceous and clay or water glass and permanganic acid of agricultural and forest by-products consisting of corn stalk, rice straw, sawdust and rice hull in the environment-friendly fuel composition and briquette production method using the same. Environment-friendly briquettes consisting of potassium, calcium carbonate and sodium hydroxide and a method for manufacturing the same are presented. In the manufacturing method of the solid fuel, the method of manufacturing a solid fuel is compressed to high temperature by adding soil or ocher powder to rice straw and mugwort powder. It proposes a method for producing solid fuel by molding.

Rice straw produced 6,236,000 tons in Korea as of 2006, although most of the biomass is derived from agricultural and forest by-products, most of the straw is used for forage, barn litter and compost. The energy of rice straw is characterized by high ash content of about 10%, low calorific value of about 3,600kcal / kg, and high content of corrosion-causing substances such as chlorine and nitrogen, and air pollution. For this reason, rice straw has not been used for power plants or heating fuels that require high quality fuel such as low ash content and high thermal efficiency. Nevertheless, conventional methods for producing solid fuel using rice straws do not suggest methods for reducing the ash content of rice straw or improving the calorific value and improving the energy properties of rice straw. It suggests only a method for producing a solid fuel by mixing with other agricultural by-products such as rice husk and wormwood powder, and does not suggest a method for producing a solid fuel using only rice straw. In addition, there is a problem of reducing the performance of the solid fuel using rice straw by adding components such as chaff, clay, calcium carbonate, ocher powder, etc., rather, increasing the ash content or reducing the calorific value.

The present invention reduces the ash content of rice straw and improves calorific value, while hydrofluoric acid, acetic acid, and anhydrous citric acid are added to distilled water to reduce chlorine and nitrogen content. It consists of a step of adding a certain ratio to react in a reaction tank in which activated carbon is embedded and a molding step of molding the rice straw into a certain form.

As a method for reducing ash contained in rice straw, improving calorific value and primary removal of chlorine and nitrogen, firstly, 0.5 ~ 30% hydrofluoric acid solution with hydrofluoric acid added 0.1 ~ 10% by weight of straw straw. After adding rice straw crushed to 5.0 mm, heated to 25-100 ° C. in a reaction tank containing activated carbon at the center, and reacted for 1 to 24 hours while stirring at a speed of 50 to 300 rpm to filter and dry ash containing rice straw. Decreases, improves calorific value and removes chlorine and nitrogen. Second, one selected from acetic acid and anhydrous citric acid is 1-10% or acetic acid and anhydrous anhydrous. Citric acid) is mixed at a constant rate, and the straw is crushed 0.5 ~ 5.0 mm in distilled water 5 ~ 30 times the weight of rice straw added 1 ~ 10%, and then heated to 25 ~ 100 ℃ in the reaction tank containing activated carbon in the center. And stir at 50 to 300 rpm. By standing 1 ~ 24 hours after the reaction it was filtered and dried to a method for reducing the ash content, which contains the rice straw and to improve the amount of heat generated and eliminate chlorine and nitrogen. Third, by continuously treating the method of reacting the aqueous solution of hydrofluoric acid and the method of reacting the aqueous solution with acetic acid and citric anhydride selectively or in a fixed ratio, thereby reducing ash contained in rice straw and improving the amount of heat generated. It is a method of removing chlorine and nitrogen.

The method of molding the rice straw into a uniform form is dried 0.5 to 5.0 after drying the modified rice straw with a water content of 1 to 15% or less using the hydrofluoric acid, acetic acid, anhydrous citric acid and activated carbon. Pulverized to ㎜, starch, paraffin wax, molasses, vegetable oil, vegetable fatty acid, lignin sulfate (lignin sulphate) selected by adding a binder or mixed in a certain proportion of 0.1 ~ 2.0% of the total weight and then extruded diameter of 6 ~ 8mm Method of producing solid fuel with diameter of 6-8mm, length 32mm or less and apparent density of 500kg / ㎥ or more by extruding for 3 to 30 minutes at an extrusion pressure of 80 to 1,000kgf / ㎠ at a temperature of 70 to 180 ° C using an internal and external extrusion machine. to be.

The energy characteristics of rice straw are about 10% of ash content, low calorific value of about 3,600kcal / kg, and high content of harmful substances such as chlorine and nitrogen. While they did not suggest techniques for improving the energy properties of rice straw, such as the method of reducing the ash content of rice straw or improving the calorific value, the present invention has a ash content of 0.7% or less, a calorific value of 4,300 kcal / kg or more, and chlorine. A method for producing high quality solid fuel with a content of 0.05% or less and a nitrogen content of 0.3% or less and a method for producing a high quality solid fuel having an apparent density of 500 kg / m 3 or more and a fine content of 2.0% or less by deriving molding conditions suitable for the characteristics of rice straw. This will enhance the industrial use and added value of rice straw as a bioenergy source.

In order to achieve the above object, the present invention provides 0.5 to 5.0 mm in hydrofluoric acid solution of 5 to 30 times the weight of straw straw to which hydrofluoric acid (Hydrofluloric acid) is added by 0.1 to 10% by weight in preparing solid fuel using rice straw. After adding the crushed rice straw, the reaction was filtered and dried for 1 to 24 hours while stirring at a speed of 50 to 300 rpm at a temperature of 25 to 100 ° C. to reduce ash contained in the rice straw and to improve calorific value. Reduced chlorine and nitrogen content, 1 ~ 10% selected from acetic acid and anhydrous citric acid, or acetic acid and anhydrous citric acid mixed in a certain ratio 10% added rice straw was reacted with 5% to 30 times the weight of distilled water in hydrofluoric acid, and then filtered rice straw was added. After 24 hours reaction And dried to reduce the ash content, which two drive containing the rice straw, improving the heating value sikimyeo reduced the chlorine and nitrogen content. In addition, in order to mold the rice straw into a uniform form, the modified straw is dried using a hydrofluoric acid, acetic acid, anhydrous citric acid, and activated carbon with a water content of 1 to 15% or less, and then 0.5 to 5.0. Pulverized to ㎜, starch, paraffin wax, molasses, vegetable oil, vegetable fatty acid, lignin sulfate (lignin sulphate) selected by adding a binder or mixed in a certain proportion of 0.1 ~ 2.0% of the total weight and then extruded diameter of 6 ~ 8mm By extruding at a temperature of 70-180 ° C. for 3-30 minutes at an extrusion pressure of 80-1,000 kgf / cm 2, solid fuels having a diameter of 6-8 mm, a length of 32 mm or less and an apparent density of 500 kg / m 3 or more were manufactured.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited by the following examples, and various modifications or changes can be made within the spirit and scope of the present invention to those skilled in the art.

Example 1

For the present invention, the physicochemical properties of rice straw were identified, including moisture content, ash, mineral and chlorine content, lignin and cellulose content, constituent consumption, and calorific value of rice straw. It was. The moisture content was measured using a moisture meter (OHAUS, Model: MB-23), and the ash content was measured after incubation for 3 hours at a temperature of 575 ± 25 ° C. in an electric furnace using a direct ignition method. The analysis was carried out using a line analyzer (ED-XRF), ligrin was analyzed by Klason method, cellulose was Wise method, member consumption was analyzed by elemental analyzer (Model: EA1112), calorific value by automatic calorimeter (Model: AC350).

Rice straw division Moisture content (%) Ash content (%) Lignin (%) cellulose(%) Calorific value (kcal / kg) Composition ratio 6.62 13.01 12.83 54.64 3622.9

Rice straw mineral and chlorine content division Al Si P S Cl K Ca Mn Fe Zn Sr Sn Pb Composition ratio (%) 1.24 3.44 0.23 0.24 2.92 16.81 2.03 0.29 0.07 0.007 0.003 0 0

Straw straw division C H N O Composition ratio (%) 39.12 4.89 1.59 53.67

Example 2

Refer to the physicochemical characteristics of the rice straw analyzed in Example 1 30% of straw straw pulverized to 1-3 mm in 600 grams of hydrofluoric acid solution in which 1-5% of hydrofluoric acid (50% by weight) was added. After adding grams, the mixture was sealed and stirred for 24 hours at a speed of 120 rpm using a shake incubator (Hanbaek Science, Model: HB-201SF) at a temperature of 45 ℃, filtered and dried using a 125 mesh sieve, and dried directly. The ash reduction effect (equivalent to 10% water content) of the dried sample was evaluated using X-ray analyzer, and the chlorine and nitrogen content reduction effect was evaluated by X-ray analyzer (ED-XRF). Evaluated.

Changes of Rice Straw Characteristics According to Folic Acid Concentration division Ash content (%) Calorific Value (kcal / kg) Goat(%) nitrogen(%) No treatment group 13.01 3622.9 2.92 1.59 Foshan 1% 3.31 3908.1 0.29 0.23 Foshan 2% 3.67 3920.8 0.28 0.25 Foshan 3% 3.68 3933.5 0.29 0.19 Foshan 4% 3.14 4059.2 0.25 0.19 Foshan 5% 2.72 4092.4 0.23 0.18

Example 3

To 600 grams of distilled water, add 3% acetic acid (99.5%, Duksan Chemical) and 1-6% citric anhydride (Express, Junsei), respectively, and add 30 grams of rice straw filtered through the 5% hydrofluoric acid treatment group of Example 2. After that, the mixture was sealed and stirred at a speed of 120 rpm for 3 hours using a 1 liter reactor equipped with a pore 10 μm and a 25 cm long stick-type activated carbon at a temperature of 55 ° C., and then filtered and dried using a 125 mesh sieve. The ash reduction effect (equivalent to 10% water content) was evaluated using the direct ashing method, and the chlorine and nitrogen content reduction effect was evaluated using the X-ray analyzer (ED-XRF). Evaluated.

Changes of Rice Straw Properties According to Acetic Acid, Citric Anhydride Composition and Activated Carbon Adsorption division Ash content (%) Calorific Value (kcal / kg) Goat(%) nitrogen(%) Foshan 5% treatment group 2.72 4092.4 0.23 0.18 Acetic acid 3% + Anhydrous 1% 1.80 4153.6 Not detected 0.03 Acetic acid 3% + Anhydrous acidic 2% 1.25 4140.7 Not detected 0.04 Acetic acid 3% + Anhydrous acidic 3% 1.13 4155.3 Not detected 0.03 Acetic acid 3% + Anhydrous acidic 4% 1.14 4195.1 Not detected 0.03 Acetic acid 3% + Anhydrous acidic 5% 0.99 4270.1 Not detected 0.02 Acetic acid 3% + Anhydrous citric acid 6% 0.68 4310.2 Not detected 0.02

Example 4

After filtering 3% acetic acid 3% + citric anhydride 6% of the Example 3 using a 125 mesh sieve, using a hot air dryer (Hanbaek Science Model: HB-502M) at 55 ℃ 72 hours after drying for 1 ~ 3mm size After grinding, water content was adjusted to 10% and corn starch was added to 2% by weight, which was used for molding experiments. Solid fuel was prepared by fixing the time to 10 minutes, changing the compaction pressure to 300 ~ 800kgf / kg, and changing the compaction temperature to 90 ~ 120 ℃, and using the apparent density measuring vessel and the vibrating body, Measured.

Apparent Density Changes of Rice Straw Solid Fuel with Different Compressive Temperature and Compressive Pressure division 300kgf / ㎠ 400kgf / ㎠ 500kgf / ㎠ 600kgf / ㎠ 700kgf / ㎠ 800kgf / ㎠ 90 ℃ 679.1kg / ㎥ 693.0kg / ㎥ 709.3kg / ㎥ 721.7kg / ㎥ 752.4kg / ㎥ 752.4kg / ㎥ 100 ℃ 678.3kg / ㎥ 692.2kg / ㎥ 706.3kg / ㎥ 722.2kg / ㎥ 738.5kg / ㎥ 755.6kg / ㎥ 110 ℃ 683.0kg / ㎥ 697.0kg / ㎥ 711.2kg / ㎥ 726.7kg / ㎥ 743.6kg / ㎥ 760.8kg / ㎥ 120 ℃ 697.0kg / ㎥ 712.2kg / ㎥ 725.7kg / ㎥ 741.5kg / ㎥ 756.7kg / ㎥ 769.1kg / ㎥

Changes in the Generation of Rice Straw Solid Fuel Particles According to the Compressive Temperature and Compressive Pressure division 300kgf / ㎠ 400kgf / ㎠ 500kgf / ㎠ 600kgf / ㎠ 700kgf / ㎠ 800kgf / ㎠ 90 ℃ 1.01% 0.94% 0.88% 0.82% 0.77% 0.72% 100 ℃ 0.81% 0.77% 0.73% 0.69% 0.65% 0.61% 110 ℃ 0.79% 0.74% 0.70% 0.66% 0.63% 0.59% 120 ℃ 0.75% 0.73% 0.69% 0.67% 0.64% 0.58%

1 is a process diagram of manufacturing solid fuel using rice straw

2 is a chlorine and nitrogen adsorption process using activated carbon

3 is a picture of rice straw solid fuel

Claims

Grinding 0.5 ~ 5.0 mm in hydrofluoric acid solution of 5 ~ 30 times the weight of straw with hydrofluoric acid added 0.1 ~ 10% by weight as a method for reducing ash content, improving calorific value and reducing chlorine and nitrogen content of rice straw After adding the rice straw, the method is heated to 25 ~ 100 ℃ in the reaction tank, and stirred at a speed of 50 ~ 300rpm after 1 to 24 hours and then filtered and dried

1-10% selected from acetic acid and anhydrous citric acid or acetic acid and citric acid as a method for reducing ash content, improving calorific value and reducing chlorine and nitrogen content in rice straw (Anhydrous citric acid) is mixed at a constant ratio and added 1 ~ 10% rice straw to 5 ~ 30 times of distilled water.Added rice straw crushed to 0.5 ~ 5.0mm and heated to 25 ~ 100 ℃ in a reactor Filtration and drying after the reaction for 1 to 24 hours while stirring at a speed of

Reaction with hydrofluoric acid solution of claim 1 as a method for reducing ash content, improving calorific value and reducing chlorine and nitrogen content in rice straw, and reacting with aqueous solution added by mixing acetic acid and citric anhydride of claim 2 selectively or in a fixed ratio Filtration and drying by continuous treatment

Method of adsorbing chlorine and nitrogen for 10 to 240 minutes by incorporating activated carbon in the center of the reactors of claims 1, 2 and 3 to reduce the chlorine and nitrogen content of rice straw

In order to reduce the content of chlorine and nitrogen contained in rice straw, chlorine was introduced into the reaction tank containing activated carbon at the rate of 50-2000 ml per minute in the reaction tank containing activated carbon in the center by using a transfer pump. To adsorb nitrogen and nitrogen

Rice straw is a method of forming a straw in a uniform form by drying the rice straw obtained by the method described in claim 1, claim 2, claim 3, claim 4, claim 5 with a water content of 1 to 15% and pulverized to 0.5 ~ 5.0㎜ and starch, paraffin Wax, molasses, vegetable oil, vegetable fatty acid, lignin sulfate (lignin sulphate) or a binder mixed in a certain ratio of 0.1 ~ 2.0% of the total weight of the extruder by using an extrusion molding machine of about 6 ~ 8mm diameter Method of producing a solid fuel by pressing for 3 to 30 minutes at an extrusion pressure of 80 ~ 1,000kgf / ㎠ at a temperature of 70 ~ 180 ℃