RU2773500C1 - Method for obtaining fuel briquettes from carbon-containing waste - Google Patents

Abstract

FIELD: fuel briquettes.

SUBSTANCE: invention relates to fuel briquettes. A method for producing fuel briquettes from carbon-containing waste is proposed, characterized in that paper product waste is mixed with water and hydrogen peroxide in an amount of 10 to 15 kg/t for 50 to 60 minutes at a humidity of the mixed mass of 45 to 60%, before finishing mixing tall oil in an amount of 100 to 500 g/t and pine oil in an amount of 40 to 60 g/t are added, then the resulting mass is diluted with water, subjected to froth flotation, to obtain a chamber product, which is mixed together with wood waste, which are used as pine-birch sawdust, and with hydrolytic lignin, thickening is carried out, followed by the formation of fuel briquettes, while the content of components in the briquette is pine-birch sawdust from 30 to 60%, waste paper products from 30 to 60%, hydrolytic lignin from 8 to 20%.

EFFECT: simplification of briquette manufacturing technology and reduction of environmental impact.

1 cl, 4 tbl

Description

The invention relates to the production of fuel briquettes from carbon-containing secondary raw materials, in particular woodworking and woodworking waste. At the same time, practically unclaimed materials are being utilized and, accordingly, the environmental problem is being solved.

A known method for producing a fuel briquette (RF patent No. 2533426, publ. 11/20/2014), which includes grinding wood waste, mixing, drying and subsequent pressing, while as an additional element, the briquette contains a core of pressed aspen sawdust with a hole for traction.

The main disadvantages of the method are the high need for wood waste shredding and the use of an additional core element made of aspen sawdust, which leads to an increase in the number of operations for the production of briquettes, correspondingly complicating the technology of their production. Also, the resulting briquettes have low strength.

Fuel briquettes are known (RF patent No. 2653513, published on May 10, 2018), from a two-component mixture of vegetable, preferably wood, origin: the first component is crushed wood waste from wood processing enterprises and / or wood processing enterprises, and the second component is charcoal, characterized in that a two-component mixture is presented in the form of a homogenized composite material obtained by compounding a matrix of crushed wood waste and hardening dispersed particles of charcoal, carried out in two stages: the first stage - by combining the following simultaneously occurring processes: drying wood waste with the original natural moisture, dispersion of the original charcoal and adsorption to a matrix of dispersed charcoal; and the second stage - in the process of briquetting the composite material, preferably by extrusion, and the combination of drying, dispersion and adsorption is carried out in a dynamic looped heat flow of a mixture of flue gases with wood waste moisture vapor released during the drying process, while the charcoal content in the feedstock is maintained at within 5÷30 wt. %.

The main disadvantages of the method are in a large number of operations for the production of briquettes, which significantly complicates the technology of their production and increases energy costs. Also, the resulting briquettes have low strength.

A known method for producing fuel pellets briquettes (RF patent No. 2369631, published: 10.10.2009), from biological material, preferably sawdust, wood, etc., in which the material is fed to the drying stage and this material is dried to a relative humidity value of 40-65 to 30-45 wt.%, the material is fed from the drying stage, possibly through an intermediate storage stage, to the reactor stage and the material is treated at elevated pressure and heated to 200-300°C by supplying steam; the material is kept in the reactor at the reached temperature for a time sufficient to soften the material; the pressure in the reactor stage is reduced in at least two stages, with the first stage of pressure reduction being carried out to defiberize the material and recover lignin, and the second stage of pressure reduction to feed the material from the reactor stage to an additional drying stage, possibly through an intermediate stage storage and material is granulated.

The main disadvantages of the method are in a large number of operations for the production of briquettes, including the use of heating operations at elevated pressure, which complicates the technology of their production and significantly increases energy costs. Also, the resulting briquettes have low strength.

A known method for producing granules or briquettes (RF patent No. 2518068 published 06/10/2014) from lignin-containing material, including stages in which: lignin-containing material is passed, having a moisture content of less than about 30% by weight, into the reactor; where the lignin-containing material is heated to a temperature of 180-235°C by steam injection into the reactor; keep the material in the reactor for 1-12 minutes to separate lignin; reduce the pressure in the reactor; and shaping the treated material into granules or briquettes.

The main disadvantages of the method are in a large number of operations for the production of briquettes, including the use of heating operations with steam injection, which complicates the technology of their production and significantly increases energy costs.

A known method for producing fuel briquettes from carbon-containing waste (patent No. 2653362, published, 05/08/2018) adopted as a prototype, including grinding, drying to a moisture content of 12-16%, mixing the components of the mixture, including technical hydrolysis lignin, and the preparation of the binder charge is carried out by adding 70-80% sodium carbonate 5-10% to technical hydrolysis lignin and further mechanical activation followed by the addition of tall pitch 15-20% heated to 90 ° C, the resulting mixture in the amount of 10-15% is mixed with wood waste, crushed to 1- 5 mm in the amount of 85-90%, and the briquetting of the mixture is carried out at a temperature of 90±2°C and a pressure of 45-50 MPa.

The main disadvantages of the method are in a large number of operations for the production of briquettes, including the use of mechanical activation and heating operations at elevated pressure, which complicates the production technology and significantly increases energy costs.

The technical result is the simplification of the technology for the manufacture of briquettes and the reduction of the burden on the environment due to the removal during the production of briquettes of harmful impurities passing into the atmosphere during combustion, as well as the disposal of polluting carbon-containing waste.

The technical result is achieved by mixing waste paper products with water and hydrogen peroxide in an amount of 10 to 15 kg/t for 50 to 60 minutes at a moisture content of the mixed mass of 45 to 60%; before the end of mixing, tall oil is added in an amount of from 100 to 500 g / t and pine oil in an amount of 40 to 60 g / t, then the resulting mass is diluted with water and subjected to froth flotation, obtaining a froth product, which is sent to the dump, and a chamber product, which is mixed together with wood waste, as which pine-birch sawdust and hydrolytic lignin are used, and then thickening is carried out, followed by the formation of fuel briquettes, while the content of components in the briquette is pine-birch sawdust from 30 to 60%, waste paper products from 30 to 60%, hydrolysis lignin from 8 to 20%.

The method is carried out as follows. Waste printed paper products are mixed with water and hydrogen peroxide in an amount of 10 to 15 kg / t, in a mixer for 50 to 60 minutes at a humidity of the mixed mass in the range from 45 to 60%. In this case, the destruction of paper waste to flotation size, the removal of paint from the surface of the paper and the separation of inorganic contaminants from paper waste. Some time before the end of the mixing process, tall oil in the amount of 100 to 500 g/t and pine oil in the amount of 40 to 60 g/t are fed into this operation. Tall oil is a collecting agent, pine oil is a foaming agent. The resulting mass is then diluted with water and subjected to froth flotation in a flotation machine at room temperature. During flotation, foam and chamber products are formed. The main part of the paint and all kinds of inorganic impurities that fall into paper waste pass into the foam product. The foam product is sent to the dump.

The chamber product, consisting of purified paper waste, is thickened and mixed with wood waste, which is used as pine-birch sawdust, and hydrolytic lignin. Then carry out the thickening of the resulting mixture, for example, in a hydrocyclone. Briquettes are formed from the resulting mixture, for example, by extrusion. The content of components in the briquette is pine-birch sawdust from 30 to 60%, waste of printed materials from 30 to 60%, hydrolytic lignin from 8 to 20%. Paper waste acts both as a binder and as an energy carrier. The use of paper waste makes it possible to form briquettes at relatively low pressures, which simplifies the technology and makes it possible to obtain sufficiently strong briquettes.

The method is illustrated by the following examples.

Waste of printed products, mainly newsprint, was used as the feedstock. These wastes were placed in a flotation machine and mixed with water without air supply to the flotation machine. The reagents were fed into the mixing process in the following order: hydrogen peroxide at the beginning of mixing, tall oil and pine oil - 2 minutes before the end of the mixing process. Then the solids content in the cell was brought to about 40% by adding water and flotation was carried out. Flotation was carried out in an alkaline environment created by caustic soda. The flotation foam was continuously removed from the cell.

After flotation, the chamber product remaining in the flotation machine was thickened, mixed with pine-birch sawdust, which is a waste of woodworking and hydrolytic lignin, which is a waste of the pulp and paper industry. Then the briquettes were molded by extrusion. The resulting briquettes were dried either by force, by heating to 105°C, or by keeping at room temperature.

Table 1 shows the dependence of the technological parameters of flotation and the strength of the resulting briquettes on the mixing time. The ratio in the briquette - sawdust, paper waste, hydrolytic lignin - 44:45:10. Reagent consumption: tall oil - 300 g/t, pine oil - 50 g/t, hydrogen peroxide - 12 g/t.

Table 1 - Dependence of technological indicators of flotation and briquette strength on mixing time

No. Mixing time, min Yield of froth product of flotation, % Paint content in foam product, % Extraction of paint in the foam product, % Briquette strength, MPa/briquette one thirty 3.21 22.32 39.80 3.6 2 fifty 5.02 32.82 91.53 4.8 3 60 4.98 32.79 90.72 5.2 four 70 4.53 32.16 80.94 5.2

Mixing allows you to grind paper waste to flotation size and wipe the ink from the surface of the paper. At the same time, the separation of possible inorganic impurities that have fallen into paper waste occurs. The mixing time of less than 50 minutes does not allow achieving the required degree of paper waste grinding, sufficient complete removal of ink from the paper surface and separation of inorganic impurities from the paper surface. Mixing times of more than 60 minutes lead to over-grinding of the paper, which worsens the flotation results and leads to additional energy consumption. At the same time, the degree of paint removal and separation of inorganic impurities practically does not increase.

Table 2 shows the dependence of the technological parameters of flotation and the strength of the briquette on the moisture content of the mixed mass. The ratio in the briquette - sawdust, paper waste, hydrolytic lignin - 44:45:10 wt. %. Reagents consumption: tall oil - 300 g/t, pine oil - 50 g/t, hydrogen peroxide - 12 g/t, mixing time - 55 minutes.

Table 2 - Dependence of technological indicators of flotation and briquette strength on the humidity of the mixed mass.

No. Humidity of the stirred mass, % Yield of froth product of flotation, % Paint content in foam product, % Extraction of paint in the foam product, % Briquette strength, MPa/briquette one 40 4.25 24.46 57.75 5.1 2 45 5.11 32.76 93.00 5.1 3 60 5.12 32.84 93.41 5.2 four 70 5.02 30.82 85.95 5.2

The humidity of the mixed mass is less than 45%, which makes it possible to effectively mix it due to a sharp increase in the viscosity of the mass. Humidity of the mass above 60% leads to a decrease in the efficiency of paint removal and separation of inorganic contaminants due to a decrease in the contact surface of rubbing particles during mixing.

Table 3 shows the strength of the briquette from the ratio of sawdust, paper waste, hydrolytic lignin in the briquette. Reagents consumption: tall oil - 300 g/t, pine oil - 50 g/t, hydrogen peroxide - 12 g/t, mixing time - 55 minutes.

Table 3 - Dependence of the strength of the briquette on the ratio of sawdust, paper waste, hydrolytic lignin in the briquette

No. The content of the chamber product in the briquette, wt. % The content of pine-birch sawdust in the briquette, wt. % The content of hydrolytic lignin in the briquette, wt. % Briquette strength, MPa/briquette one 32 62 6 3.1 2 32 60 eight 3.8 3 42 fifty eight 4.8 four fifty 40 ten 5.8 5 60 thirty ten 6.1 6 65 27 eight 6.1 7 45 40 fifteen 5.9 eight 40 40 twenty 5.8 9 38 40 22 5.7

The amount of chamber product in the briquette, less than 40% leads to a decrease in the strength of the produced briquettes. The amount of chamber product more than 60% does not increase the strength of the briquette and leads to a decrease in the completeness of sawdust utilization.

The amount of pine-birch sawdust used as a component for the production of fuel briquettes is more than 60 wt. % leads to a decrease in the strength of the produced briquettes. The amount of pine-birch sawdust is less than 40 wt. % does not increase the strength of the briquette and leads to a decrease in the completeness of the utilization of sawdust.

The addition of hydrolytic lignin makes it possible to increase the strength of the resulting briquettes, while simultaneously utilizing the hydrolytic lignin. The consumption of hydrolytic lignin is less than 8 wt. % practically does not increase the strength of the briquette. The increase in the consumption of hydrolytic lignin above 20 wt. % leads to difficulty in the process due to the complexity of the operation of mixing the chamber product and sawdust with lignin and due to the difficulty of forming briquettes due to an increase in the viscosity of the molded mass. In addition, an increase in the proportion of lignin leads to a decrease in the degree of utilization of paper waste and sawdust.

Table 4 shows the dependence of technological parameters of flotation on the consumption of flotation reagents. Mixing time - 55 minutes, humidity of the mixed mass 52%

Table 4 - Dependence of technological indicators of flotation on the consumption of flotation reagents

No. Tall oil consumption, g/t Pine oil consumption, g/t Hydrogen peroxide consumption, kg/t Yield of froth product of flotation, % Paint content in foam product, % Extraction of paint in the foam product, % one 80 thirty eight 3.01 20.43 34.16 2 100 40 ten 4.97 32.79 90.54 3 300 55 12 5.03 32.81 91.69 four 500 60 fifteen 5.06 32.16 90.41 5 600 70 twenty 5.47 27.14 82.48

The consumption of tall oil less than 100 g/t does not allow to fully extract the paint and inorganic contaminants into the foam product. Tall oil consumption greater than 500 g/t also leads to a reduction in the recovery of paint and inorganic contaminants in the foam product.

The consumption of pine oil less than 40 g/t leads to a decrease in the yield of the foam product due to insufficient foaming and as a result leads to a decrease in the recovery of paint and inorganic contaminants in the foam product. The consumption of pine oil more than 60 g/t worsens the technological performance due to excessive foaming.

The consumption of hydrogen peroxide less than 10 kg/t does not give a noticeable increase in separation efficiency during flotation. The consumption of hydrogen peroxide above 15 kg/t does not increase the separation efficiency, and the cost of the operation increases. Therefore, such an increase is irrational.

The inventive method makes it possible to obtain fuel briquettes suitable, for example, for domestic use. At the same time, an additional amount of energy carriers is produced according to a relatively simple technology and at the same time, such industrial wastes that are little in demand and polluting the environment, such as wood processing products, paper waste, and hydrolytic lignin, are utilized. In addition, harmful components are removed from the feedstock, which also pollute the environment during the combustion of briquettes.

Claims (1)

A method for producing fuel briquettes from carbon-containing waste, including mixing the components of a mixture, including technical hydrolytic lignin and wood waste, and briquetting the mixture, characterized in that paper product waste is mixed with water and hydrogen peroxide in an amount of 10 to 15 kg/t for from 50 to 60 minutes at a moisture content of the mixed mass from 45 to 60%, before the end of mixing, tall oil is added in an amount of 100 to 500 g/t and pine oil in an amount of 40 to 60 g/t, then the resulting mass is diluted with water and subjected to foam flotation, with the production of a foam product, which is sent to a dump, and a chamber product, which is mixed together with wood waste, which is used as pine-birch sawdust, and hydrolytic lignin, and then thickening is carried out, followed by the formation of fuel briquettes, while the content components in the briquette is pine-birch sawdust from 30 to 60%, waste paper products from 30 up to 60%, hydrolytic lignin from 8 to 20%.