RU2484124C2 - Solid-fuel granulated composition, and method for its obtainment - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to production of solid fuel, in which there described is solid-fuel granulated composition based on carbon-containing component, where as carbon-containing component, there added is disperse activated product of low-temperature pyrolysis of wastes of technical rubber products and polymer wastes (pyrocarbon with specific surface S=5000-8000 cm²/g), and wood dust is added as plant waste. At that, as the component that initiates combustion, there added are nitrogen-containing components, and binding agent is added in the form of water solution of polymer plasticising additive with total initial humidity W_initial =10÷35 wt %. Peculiar feature of granulated solid-fuel composition and method for its obtainment is increase in thermal power due to considerable acceleration of fuel combustion at reduced quantity of hazardous gaseous emission to atmosphere. Proposed ratios of components and added quantity of NH₄NO₃ as an oxidiser instead of hydrogen at combustion provides formation of NO₃, N₂ and H₂O. Excess oxygen is supplied to oxidation of fuel components.

EFFECT: obtaining fuel briquettes with high reactivity ability, increased thermal power and high strength of briquettes.

2 cl, 4 cl

Description

The invention relates to the production of solid fuels in the form of briquettes, pellets, compacts and can be used as natural fuel in everyday life, in boiler houses for domestic purposes, in industry and carbox fireboxes.

A fuel briquette is known that contains a carbon-containing component (anthracite block, coal fines, etc.), as sulphite-yeast mash and oil bitumen as binders, the latter simultaneously plays the role of water repellent, in the following ratio, wt.%: Sulphite-yeast mash (2.4 ÷ 6.4); petroleum bitumen (1.2 ÷ 4.2); anthracite block or coal fines - the rest [SU 1452841, 1989].

The disadvantage of the composition is a small moisture resistance and heat resistance.

Known fuel briquette based on a mixture of crushed carbon fuel (coke breeze, coal, charcoal), at least 5% (10 ÷ 40%) of wax (paraffin, polyethylene, oil, vegetable) and at least 2.5% (4 ÷ 15 %) a binder - maize starch, lignin, resin, which is obtained by molding and then cutting into briquettes (GB 2240341 C10L 5/14, publ. 31.07.91).

Also known is a briquette based on a mixture of crushed solid fuel from the group of plant waste products of stone fruit processing 40-75% by weight, coal or coke breeze 15-40% by weight, and a binder from the group including lignosulfonate, molasses, tack pitch or mixtures thereof - up to 100% wt. (RU 2114902, C10L 5/44, publ. 10.07.98).

These briquettes, having sufficient reactivity, have a relatively low mechanical strength, which leads to their destruction during loading and transport operations and, thus, to increased costs when using these briquettes.

The closest is a fuel briquette based on a mixture of crushed solid fuel from the group of plant waste and / or coal and / or coke breeze and a binder from the group comprising lignosulfonate, molasses, tal pitch or mixtures thereof (1 ÷ 8)% wt., And in addition, as a binder, at a certain ratio of components, wt.%, synthetic wax or paraffin (1 ÷ 7), and / or cement, clay (1 ÷ 20) and / or sludge from wastewater treatment (2 ÷ 25) is used at the total content of at least three binders (5 ÷ 50) and crushed solid fuel (up to 100) [RU 21470 29, C10L 5/12, publ. 03/27/2000]. Briquettes have high reactivity, reduced burning time, low cracking strength of briquettes, high moisture content of the briquette and a wide range of harmful gas oxides during combustion (NO _x , CO ₂ , P ₂ O ₅ , etc.), low thermal power. In addition, there are no substances initiating the combustion process of the components. At the same time, a method is known for briquetting difficultly burned shredded tobacco and / or woodworking waste products intended for burning in furnaces, including mixing the components and briquetting. Spent engine oil and peat are used as initiating components in the briquette in the following ratio of components, wt.%: Shredded tobacco and / or woodworking waste (20 ÷ 45), used motor oil (3,5 ÷ 14,0), peat (41.0 ÷ 76.5), water (in excess of 100%) - the required amount [RU 2157402, C1, publ. 10.10.2000].

Briquetting is carried out in the following order. The crushed wastes of the tobacco or woodworking industry (crumbs, sawdust) are mixed with peat, the used machine oil and water are added in an amount of 10% by weight of the available components, and they are mixed for 3-5 minutes in a mixer until a pasty consistency is obtained, from which after extrusion is obtained cylindrical granules, or after briquetting under a pressure of 75 ÷ 100 MPa, briquettes are obtained, and then dried at a temperature of t = 100 ÷ 150 ° C.

The disadvantages of the known fuel briquette and the method of its production are: low calorific value, use of peat and engine oil as a combustion initiator, which increases the content of harmful impurities in gas emissions, and the use of water as a binder leads to high briquette moisture, its low strength and high energy consumption during granulation. The resulting briquettes have low thermal power.

The main objective of the invention is to obtain fuel briquettes with high reactivity, increased thermal power, high strength briquettes (compacts) with a low content of harmful impurities in gas emissions.

This goal is achieved by the fact that in the solid-fuel granular composition based on carbon-containing components and / or coal dust, and / or coke breeze, vegetable waste, a binder and a combustion-enhancing component, a dispersed activated product of low-temperature pyrolysis of rubber products waste is introduced as a carbon-containing component (in particular car tires) and pyrocarbon polymeric waste with specific surface area S = 5000 ÷ 8000 cm ² / g; sawdust. In this case, nitrogen-containing components, such as ammonium nitrate and / or lime-ammonium nitrate or urea, a binder polymer plasticizing additive, are introduced in the form of an aqueous solution of polyvinyl acetate with a plasticizer and / or technical lignosulfonate with a total initial moisture content W _ref = 10 ÷ 35% wt., with the following ratio of components in the granular product (% wt.):

Pyrocarbon 50 ÷ 70 Sawdust 30 ÷ 20 Nitrogen-containing substances 10 ÷ 5 An aqueous solution of a polymer plasticizing additive 10 ÷ 5

The proposed granular solid fuel composition is obtained as follows. First, nitrogen-containing components and wood-and-vegetable waste are mixed and crushed and mechanically activated in a high-speed ball mill, then this mixture is mixed with pyrocarbon, with a specific surface of S = 5000 ÷ 8000 cm ² / g with the stated binder with a total mixture moisture W _ref = 10 ÷ 20% wt. in a high-speed mixer, and then granulated at a specific pressure of 20 ÷ 115 MPa.

Pressing can be carried out by tabletting at a pressure of 20 ÷ 60 MPa, rolling on a roller press to obtain tiles at a pressure of 40 ÷ 115 MPa (hereinafter crushing into granules), briquetting on a briquette press (or in a rotary granulator with an annular or flat matrix) at a pressure of 20 ÷ 80 MPa.

A feature of this granular solid fuel composition and its production method is an increase in thermal power due to a significant acceleration of fuel combustion with a reduced amount of harmful gas emissions into the atmosphere. The claimed ratios of the components and the amount of NH ₄ NO ₃ introduced as an oxidizing agent instead of oxygen during combustion provide the formation of NO ₂ , N ₂ and H ₂ O. In this case, excess oxygen is used to oxidize the fuel components.

The phased process of mechanical activation allows to increase the specific surface of the granulated mixture and increase the surface energy of the particles. Activated particles of a mixture with a given specific surface in combination with the declared binders (aqueous solution of polyvinyl acetate and / or technical lignosulfonate) and with a reduced binder content (W _ref = 10 ÷ 20% wt.) Allow tight compresses with a cracking strength σ _split = 2 ÷ 8 MPa and a compressive strength σ _SJ = 10 ÷ 20 MPa.

Example 1

The following components were used: as a solid fuel - pyrocarbon 50%, sawdust 30%, nitrogen-containing components 10% (ammonium nitrate), an aqueous solution of a plasticizing additive 10%.

These components, after mixing and activation, at a mixture humidity W _ref = 10%, were subjected to granulation by pressing (40 ÷ 75 MPa) in various ways: by tabletting (specific pressing pressure of 40 MPa), compacting (specific pressing pressure of 60 MPa) and briquetting (specific pressing pressure 75 MPa). During tabletting, we obtained cylindrical compacts with a diameter of 15 mm, a height of 5–15 mm, a density of compacts of 1250 kg / m ³ , compressive strength of 12–15 MPa, and a calorific value of 6800 kcal / kg. Pressings light up for 7 minutes at a temperature of 600 ° C and completely burn out in 3.5 ÷ 4.5 hours without residue in the ash of combustible substances.

Example 2

The following components were used: as a solid fuel - pyrocarbon 70%, sawdust 20%, nitrogen-containing components (lime-ammonium nitrate) 5%, an aqueous solution of a polymer plasticizing additive 5%.

These components, after mixing and activation, at a mixture moisture W and _cx = 15%, were subjected to pelletizing granulation. The specific pressing pressure was 115 MPa. In this case, cylindrical compacts were obtained with a diameter of 15 mm, a height of 5 ÷ 15 mm, an average density of compacts of 1300 kg / m ³ , compressive strength of 15 ÷ 17 MPa, with a calorific value of 6950 kcal / kg. Pressings light up for 6 minutes at a temperature of 550 ° C and completely burn out in 3 ÷ 4 hours without residue in the ash of combustible substances.

Example 3

The following components were used: as solid fuel — pyrocarbon 65%, sawdust 20%, nitrogen-containing component (urea) 10%, an aqueous solution of a 5% polymer plasticizing additive.

First, the solid components of the composition were mixed and mechanically activated, then a binder (an aqueous solution of a polymer plasticizing additive) was introduced into the resulting mixture, then the activated mixture was granulated with the initial moisture content of the mixture W and _cx = 20%. When compacting, the specific pressing pressure was 115 MPa. In this case, tiles with a thickness of 5 mm were obtained, the average density of the compacts was 1400 kg / m ³ , the compressive strength was 25–30 MPa, and the calorific value was 7250 kcal / kg. Pressings light up for 4-5 minutes at a temperature of 550 ° C and completely burn out in 3-4 hours without residue in the ash of combustible substances.

Example 4

The following components were used: pyrocarbon 60%, sawdust 30%, nitrogen-containing components (calcium-ammonium nitrate) 5%, technical lignosulfonate 5% as solid fuel.

First, the solid components of the composition were mixed and mechanically activated, then a binder (technical lignosulfonate) was introduced into the resulting mixture, then the activated mixture was granulated with the initial moisture content of the mixture W and _cx = 26%. When briquetting, the specific pressing pressure was 120 MPa. In this case, compacts with a diameter of 15 mm and a height of 14 mm were obtained, the average density of compacts was 1350 kg / m ³ , compressive strength 18 ÷ 22 MPa, with a calorific value of 7000 kcal / kg. Pressings light up for 4 minutes at a temperature of 550 ° C and completely burn out in 4–5 hours without residue in the ash of combustible substances.

Example 5

The following components were used: as a solid fuel - pyrocarbon 70%, sawdust 20%, nitrogen-containing components (lime-ammonium nitrate) 5%, an aqueous solution of a polymer plasticizing additive 5%.

First, the solid components of the composition were mixed and mechanically activated, then a binder was introduced into the resulting mixture, then the activated mixture was granulated with the initial humidity of the mixture W _ref = 16%. When tabletting, the specific pressing pressure was 70 MPa. In this case, cylindrical compacts were obtained with a diameter of 15 mm, a height of 12 mm, an average density of compacts of 1370 kg / m ³ , compressive strength of 20 ÷ 25 MPa, with a calorific value of 7400 kcal / kg. Pressings light up for 3 minutes at a temperature of 500 ° C and completely burn out in 1.5 ÷ 2 hours without residue in the ash of combustible substances.

The considered examples showed that the achievement of the task is realized with the proposed composition of the solid fuel composition. The methods for its preparation allow to increase the calorific value of the composition, to intensify the combustion process due to the optimal ratio of the claimed components. At the same time, the resulting granules, compacts and briquettes have high mechanical strength and density, which reduces the cost of their use and facilitates transportation, allows the use of a large amount of waste. Fuel briquettes have a low ash content, and when burned, they have minimal emissions of harmful substances into the atmosphere at the MPC level.

Claims (5)

1. A solid fuel granular composition based on carbon-containing components and / or coal dust, and / or coke breeze, plant waste, a binder and a combustion-enhancing component, characterized in that a dispersed, activated product of low-temperature pyrolysis of rubber products - pyrocarbon is introduced as a carbon-containing component a specific surface area S = 5000 ÷ 8000 cm ² / g, as vegetable waste - sawdust, and as a component intensifying combustion using nitrogen-containing substances, the binder is introduced as an aqueous solution of a polymeric plasticizer containing no chlorine with a total moisture content of 10 ÷ 35% by weight of the following component ratio, wt.%.:
Pyrocarbon 50 ÷ 70 Sawdust 30 ÷ 20 Nitrogen-containing substances 10 ÷ 5 An aqueous solution of a polymer plasticizing additive 10 ÷ 5 2. The solid-fuel granular composition according to claim 1, characterized in that ammonium nitrate and / or calcium-ammonium nitrate and / or urea are used as nitrogen-containing components. 3. The solid fuel granular composition according to claim 1, characterized in that an aqueous solution of polyvinyl acetate with a plasticizer and / or technical lignosulfonate are used as a binder. 4. A method of producing a solid fuel granular composition based on carbon-containing components, including dosing and mixing carbon-containing components and wood-vegetable waste, their activation, mixing with a binder and granulating the mixture to produce briquettes or compacts, characterized in that the wood chips and nitrogen-containing substances are first mixed , the resulting mixture is subjected to crushing and mechanical activation in a high-speed ball mill to a specific surface S = 5000 ÷ 8000 cm ² / g, then the resulting mixture is mixed They are pressed with pyrocarbon and with a binder, and pressing is carried out at a mixture humidity w _ref = 10 ÷ 20 wt.% and specific pressure 20 ÷ 115 MPa. 5. The method according to claim 4, characterized in that the pressing is carried out by tabletting at a pressure of 20 ÷ 60 MPa, and / or by rolling on a roller press at a pressure of 40 ÷ 115 MPa, and / or by briquetting at a pressure of 20 ÷ 80 MPa.