Method and equipment for preparing coal-bio-heavy oil blended fuel and testing combustion characteristics of coal-bio-heavy oil blended fuel

Abstract

The invention discloses a method and equipment for preparing coal-biological heavy oil blended fuel and testing combustion characteristics, and the method for preparing the coal-biological heavy oil blended fuel comprises the following steps: uniformly mixing pulverized coal and biological heavy oil according to a set mass ratio, and drying the mixture of the pulverized coal and the biological heavy oil at a set temperature for a set time, the coal-biological heavy oil blended fuel is formed. According to the preparation method of the coal-biological heavy oil blended fuel provided by the embodiment of the invention, the coal-biological heavy oil is mixed and dried to form the coal-biological heavy oil blended fuel, so that the prepared dye has the advantages of high calorific value, few residues, high ignition speed and high burn-off rate, and the emission of gaseous pollutants such as SO2 and NOx in the combustion process is remarkably reduced; the combustion reactivity and the environmental protection performance of the fuel can be obviously improved.

Description

Technical Field

[0001] This invention relates to the field of energy development and environmental protection technology, and in particular to a method and equipment for preparing coal-bio-heavy oil blended fuel and testing its combustion characteristics. Background Technology

[0002] Coal, due to its abundant reserves and low price, has long been widely used as a major fossil fuel. However, traditional coal combustion processes suffer from drawbacks such as high ash and slag production, high emissions of sulfur oxides and nitrogen oxides, and large carbon emissions, placing a serious burden on the environment. To achieve clean and efficient combustion, various co-combustion technologies have emerged. Among them, blending coal with renewable biomass liquid fuels is an effective approach that can improve calorific value, enhance combustion characteristics, and reduce pollutant emissions.

[0003] Bio-heavy oil is a high-energy, environmentally friendly fuel produced from biomass raw materials such as agricultural waste, microalgae, and waste oil through processes like pyrolysis and esterification. Its carbon source comes from the biomass-atmosphere carbon exchange cycle, and its combustion does not increase net CO2 emissions into the atmosphere. As a byproduct of biodiesel production, bio-heavy oil mainly consists of O1~O2. 12 Composed of high-boiling-point alcohols, ketones, esters, ethers, and other oxygen-containing functional groups, bio-heavy oil possesses excellent fuel characteristics such as complete combustion, low sulfur content, clean emissions, and high calorific value. It is also widely available, inexpensive, and produced in large quantities annually. However, its direct combustion suffers from poor stability and strong corrosiveness, limiting its independent application. Currently, my country lags behind international advanced levels in the high-value utilization of bio-heavy oil, with most of it being treated as industrial waste.

[0004] Blending biofuel with coal not only improves the calorific value and combustion efficiency of coal-fired power units and reduces pollutant emissions, but also effectively addresses the resource utilization of biofuel, achieving multiple goals of energy conservation, emission reduction, and resource utilization. However, a coal-biofuel blend with high calorific value, combustion stability, and low emissions, along with optimal combustion methods, is currently lacking. Further research is urgently needed to promote the green transformation and upgrading of the coal-fired power energy structure. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one object of this invention is to provide a method for preparing a coal-bio-heavy oil blended fuel. By mixing and drying coal and bio-heavy oil to form a coal-bio-heavy oil blended fuel, the resulting fuel can have advantages such as high calorific value, low residue, rapid ignition, and high burnout rate. Furthermore, during combustion, SO2 and NO are reduced. x The emission of gaseous pollutants is significantly reduced, which can significantly improve the combustion reactivity and environmental performance of fuels.

[0006] The application further provides a coal-bio-heavy oil blended fuel prepared by the preparation method of the coal-bio-heavy oil blended fuel.

[0007] The application further provides a combustion performance testing method of the coal-bio-heavy oil blended fuel.

[0008] The application further provides a combustion performance testing device of the coal-bio-heavy oil blended fuel.

[0009] The application further provides another combustion performance testing method of the coal-bio-heavy oil blended fuel.

[0010] The application further provides still another combustion performance testing method of the coal-bio-heavy oil blended fuel.

[0011] The application further provides a preparation method of a coal-bio-heavy oil blended fuel according to the first aspect of the application, which comprises: uniformly mixing coal powder and bio-heavy oil according to a set mass ratio; and drying the mixture of the coal powder and the bio-heavy oil at a set temperature for a set time to form the coal-bio-heavy oil blended fuel.

[0012] The preparation method of the coal-bio-heavy oil blended fuel according to the application can make the prepared dye have the advantages of high calorific value, less residue, fast ignition and high burnout rate, and can significantly reduce the emission of gaseous pollutants such as SO2 and NO x during the combustion process, and can significantly improve the combustion reactivity and environmental protection performance of the fuel.

[0013] According to some embodiments of the application, the particle size of the coal powder is 200-300 mesh; and / or the bio-heavy oil is liquid by-product oil, and the sulfur content of the bio-heavy oil is <0.01%.

[0014] According to some embodiments of the application, the set mass ratio is any one of 9:1, 4:1, 7:3, 3:2, 1:1, 2:3, 3:7, 1:4 and 1:9.

[0015] According to some embodiments of the application, before the coal powder and the bio-heavy oil are uniformly mixed according to the set mass ratio and dried, a mortar is used to grind the mixture of the coal powder and the bio-heavy oil, so that the coal powder and the bio-heavy oil form a slurry.

[0016] According to some embodiments of the application, the set temperature is 100-160°C, and the set time is 12-24h.

[0017] The coal-bio-heavy oil blended fuel according to the second aspect of the present application is prepared by the preparation method of the coal-bio-heavy oil blended fuel according to the first aspect of the present application.

[0018] The coal-bio-heavy oil blended fuel according to the second aspect of the present application is prepared by the preparation method of the coal-bio-heavy oil blended fuel according to the first aspect of the present application. x The coal-bio-heavy oil blended fuel according to the second aspect of the present application has the advantages of high calorific value, less residue, fast ignition, high burnout rate, and significantly reduced emissions of gaseous pollutants such as SO2 and NOx during combustion, which can significantly improve the combustion reactivity and environmental performance of the fuel.

[0019] The coal-bio-heavy oil blended fuel according to the second aspect of the present application is prepared by the preparation method of the coal-bio-heavy oil blended fuel according to the first aspect of the present application.

[0020] The coal-bio-heavy oil blended fuel according to the second aspect of the present application is prepared by the preparation method of the coal-bio-heavy oil blended fuel according to the first aspect of the present application.

[0021] The coal-bio-heavy oil blended fuel according to the second aspect of the present application is prepared by the preparation method of the coal-bio-heavy oil blended fuel according to the first aspect of the present application.

[0022] The combustion performance test equipment of the coal-bio-oil blended fuel according to the embodiment of the present application is connected with a compressed air bottle at one end and a flue gas analyzer at the other end, and can pass the combustion products of the coal-bio-oil blended fuel into the flue gas analyzer, so that the combustion performance test equipment of the coal-bio-oil blended fuel can more accurately detect the types and contents of pollutants emitted by the coal-bio-oil blended fuel during combustion, and the monitored data is more accurate.

[0023] The combustion performance test method of the coal-bio-oil blended fuel according to the fifth aspect of the embodiment of the present application, the coal-bio-oil blended fuel is the coal-bio-oil blended fuel according to the fourth aspect of the embodiment of the present application, the combustion performance test method comprises: using a thermogravimetric analyzer and a thermogravimetric-mass spectrometer to test the pyrolysis process of the coal-bio-oil blended fuel.

[0024] The combustion performance test method of the coal-bio-oil blended fuel according to the embodiment of the present application, by using a thermogravimetric analyzer and a thermogravimetric-mass spectrometer to test the pyrolysis process of the coal-bio-oil blended fuel, the combustion process of the coal-bio-oil blended fuel can be more accurately analyzed.

[0025] The combustion performance test method of the coal-bio-oil blended fuel according to the sixth aspect of the embodiment of the present application, the coal-bio-oil blended fuel is the coal-bio-oil blended fuel according to the fourth aspect of the embodiment of the present application, the combustion performance test method comprises: making the coal-bio-oil blended fuel burn on a hot electric furnace to form a combustion flame; using a high-speed camera to capture a combustion picture of the combustion flame of the coal-bio-oil blended fuel; transferring the combustion picture to a computer and recording the height and morphology of the flame in the combustion picture.

[0026] The combustion performance test method of the coal-bio-oil blended fuel according to the embodiment of the present application, by transferring the combustion picture to the computer, the height and morphology of the combustion flame of the coal-bio-oil blended fuel can be more accurately analyzed, and the combustion condition of the coal-bio-oil blended fuel can be more accurately judged.

[0027] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0028] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, taken in conjunction with the accompanying drawings, in which: Figure 1 is a simple diagram of a combustion performance test equipment of a coal-bio-oil blended fuel according to some embodiments of the present application; Figure 2is a schematic diagram of an apparatus used for testing combustion performance of coal-bio-oil blended fuel according to some embodiments of the present application; Figure 3 is a comparison chart of calorific values of Example 1, Example 2, Example 3 and Comparative Example 1.

[0029] Reference signs: 100, an apparatus for testing combustion performance of coal-bio-oil blended fuel; 101, coal-bio-oil blended fuel; 1, compressed air bottle; 2, tube furnace assembly; 21, tube furnace; 22, test tube; 221, air inlet; 222, air outlet; 3, flue gas analyzer; 31, gas inlet; 32, gas outlet; 4, first connecting pipeline; 41, gas flow meter; 42, on-off valve; 5, second connecting pipeline; 51, pressure gauge; 6, condensation tank; 61, cooling medium; 70, hot electric furnace; 71, high-speed camera; 72, computer; 73, light source. DETAILED DESCRIPTION

[0030] Embodiments of the present application are described in detail below with reference to the accompanying drawings, in which like or similar elements or elements having the same or similar functions are denoted by the same or similar reference signs throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only for the purpose of explaining the present application, and should not be construed as limiting the present application.

[0031] Reference is made below to Figures 1-3 A method for preparing coal-bio-oil blended fuel 101 according to embodiments of the present application is described.

[0032] The method for preparing coal-bio-oil blended fuel 101 according to the first aspect of embodiments of the present application comprises: uniformly mixing the coal powder and bio-oil according to a set mass ratio; drying the mixture of coal powder and bio-oil at a set temperature for a set time to form coal-bio-oil blended fuel 101.

[0033] The calorific value of pure bio-oil is as high as 38.3 MJ·kg-1, which is significantly higher than that of pure coal and other inferior biomass raw materials such as microalgae. By mixing coal and bio-oil, the high-calorific-value liquid bio-oil can be used to replace traditional coal, thereby improving the calorific value of coal-bio-oil blended fuel 101. Bio-oil has oxygen-containing functional groups, which can promote ignition and burnout of the fuel and reduce the residue rate. In addition, SO2 and NO xThe gaseous pollutant emission is significantly reduced, the combustion reactivity of the fuel is significantly improved, and the environmental protection performance is improved.

[0034] According to the preparation method of the coal-bio-heavy oil blended fuel 101, the coal-bio-heavy oil blended fuel 101 is formed by drying the coal-bio-heavy oil mixture, and the prepared fuel has the advantages of high calorific value, less residue, fast ignition, and high burnout rate, and the SO2 and NOx emissions in the combustion process are reduced. x The gaseous pollutant emission is significantly reduced, the combustion reactivity of the fuel is significantly improved, and the environmental protection performance is improved.

[0035] According to some embodiments of the present application, the particle size of the coal powder is 200-300 mesh. By setting the particle size of the coal powder to 200-300 mesh, the coal powder can be fully contacted with the combustion-supporting material during combustion, and the combustion is more complete.

[0036] According to some embodiments of the present application, the bio-heavy oil is a liquid by-product oil, and the sulfur content of the bio-heavy oil is less than 0.01%. By making the bio-heavy oil a liquid by-product oil, the cost of the bio-heavy oil can be reduced, and by making the sulfur content of the bio-heavy oil less than 0.01%, the content of sulfur dioxide generated after combustion of the bio-heavy oil can be reduced, and pollution can be reduced.

[0037] According to some embodiments of the present application, the mass ratio is set to any one of 9:1, 4:1, 7:3, 3:2, 1:1, 2:3, 3:7, 1:4 and 1:9. By setting the mass ratio to any one of 9:1, 4:1, 7:3, 3:2, 1:1, 2:3, 3:7, 1:4 and 1:9, the coal-bio-heavy oil in the coal-bio-heavy oil blended fuel 101 can fully play a role.

[0038] Preferably, the mass ratio is set to 1:4.

[0039] According to some embodiments of the present application, before the coal powder and the bio-heavy oil are uniformly mixed according to the set mass ratio and dried, a mortar is used to grind the mixture of the coal powder and the bio-heavy oil, so that the coal powder and the bio-heavy oil form a slurry. By grinding the mixture of the coal powder and the bio-heavy oil with a mortar, the mixture of the coal powder and the bio-heavy oil can be more uniform.

[0040] According to some embodiments of the present application, the temperature is set to 100-160°C, and the time is set to 12-24h. By setting the temperature to 100-160°C and the time to 12-24h, the mixture of the coal powder and the bio-heavy oil can be dried more fully, the water content of the coal-bio-heavy oil blended fuel 101 is reduced, and the effective calorific value is improved.

[0041] The coal-bio-heavy oil blended fuel 101 according to the second aspect of the present application is prepared by the preparation method of the coal-bio-heavy oil blended fuel 101 according to the first aspect of the present application.

[0042] The coal-bio-heavy oil blended fuel 101 according to the embodiment of the present application, prepared by the preparation method of the coal-bio-heavy oil blended fuel 101 according to the first aspect of the present application, has the advantages of high calorific value, less residue, fast ignition, and high burnout rate, and the emission of gaseous pollutants such as SO2 and NO x during combustion is significantly reduced, which can significantly improve the combustion reactivity and environmental performance of the fuel.

[0043] The combustion performance test method of the coal-bio-heavy oil blended fuel 101 according to the third aspect of the present application, the coal-bio-heavy oil blended fuel 101 is the coal-bio-heavy oil blended fuel 101 according to the second aspect of the present application, the combustion performance test method of the coal-bio-heavy oil blended fuel 101 comprises: The coal-bio-heavy oil blended fuel 101 is ignited by resistance wire ignition under air atmosphere; The pollutant emission of the coal-bio-heavy oil blended fuel 101 is monitored by using an online flue gas analysis platform.

[0044] The combustion performance test method of the coal-bio-heavy oil blended fuel 101 according to the embodiment of the present application, by monitoring the pollutant emission of the coal-bio-heavy oil blended fuel 101 by using an online flue gas analysis platform, more effectively detects the types and contents of pollutants emitted by the coal-bio-heavy oil blended fuel 101 during combustion, and the monitored data is more accurate.

[0045] Referring to Figure 1 , the combustion performance test equipment 100 of the coal-bio-heavy oil blended fuel according to the fourth aspect of the present application, the combustion performance test equipment is used for the combustion performance test method according to the third aspect of the present application, the combustion performance test equipment comprises: a compressed air bottle 1, a tube furnace assembly 2, a flue gas analyzer 3 and a condensate tank 6.

[0046] The tube furnace assembly 2 comprises a tube furnace 21 and a test tube 22, the test tube 22 is arranged in the tube furnace 21, at least part of the test tube 22 is located in the tube furnace 21, the test tube 22 has an air inlet 221 and an air outlet 222, the air inlet 221 is connected with the compressed air bottle 1 through a first connecting pipeline 4, and a gas flow meter 41 is arranged on the first connecting pipeline 4.

[0047] The flue gas analyzer 3 comprises a gas inlet 31 and a gas outlet 32, the gas inlet 31 is connected with the gas outlet 222 through the second connecting pipeline 5, and the second connecting pipeline 5 is provided with a pressure gauge 51.

[0048] The condensing tank 6 is internally provided with a cooling medium 61, and at least a part of the second connecting pipeline 5 is located in the condensing tank 6 and is in contact with the cooling medium 61.

[0049] For example, the first connecting pipeline 4 is further provided with a switch valve 42, which can control the on-off connection between the compressed air bottle 1 and the gas inlet 221.

[0050] By means of the combustion performance test equipment 100 of the coal-bio-heavy oil blended fuel, the cooling medium 61 in the condensing tank 6 can cool the combustion tail gas of the coal-bio-heavy oil blended fuel 101, so that the test result of the flue gas analyzer 3 is more accurate.

[0051] For example, after the coal-bio-heavy oil blended fuel 101 is placed in the test tube 22, the compressed air bottle 1 and the flue gas analyzer 3 are opened, compressed air in the compressed air bottle 1 can be introduced into the test tube 22, the coal-bio-heavy oil blended fuel 101 is ignited, and the flue gas analyzer 3 analyzes the content of harmful substances in the tail gas according to the combustion tail gas of the coal-bio-heavy oil blended fuel 101.

[0052] According to the combustion performance test equipment 100 of the coal-bio-heavy oil blended fuel, one end of the test tube 22 is connected with the compressed air bottle 1, and the other end is connected with the flue gas analyzer 3, the combustion product of the coal-bio-heavy oil blended fuel 101 can be introduced into the flue gas analyzer 3, the combustion performance test equipment 100 of the coal-bio-heavy oil blended fuel can more accurately detect the types and contents of pollutants emitted by the coal-bio-heavy oil blended fuel 101 during combustion, and the monitored data is more accurate.

[0053] According to the combustion performance test method of the coal-bio-heavy oil blended fuel 101 according to the fifth aspect of the present application, the coal-bio-heavy oil blended fuel 101 is the coal-bio-heavy oil blended fuel 101 according to the fourth aspect of the present application, and the combustion performance test method comprises: respectively using a thermal gravimetric analyzer and a thermal gravimetric-mass spectrometer to test the pyrolysis process of the coal-bio-heavy oil blended fuel 101.

[0054] According to the combustion performance test method of the coal-bio-heavy oil blended fuel 101 according to the embodiment of the present application, the pyrolysis process of the coal-bio-heavy oil blended fuel 101 is tested by using a thermal gravimetric analyzer and a thermal gravimetric-mass spectrometer, so that the combustion process of the coal-bio-heavy oil blended fuel 101 can be more accurately analyzed.

[0055] Reference Figure 2According to a sixth aspect embodiment of the present invention, a method for testing the combustion performance of a coal-bio-heavy oil blended fuel 101, wherein the coal-bio-heavy oil blended fuel 101 is the same as the coal-bio-heavy oil blended fuel 101 according to a fourth aspect embodiment of the present invention, the method for testing the combustion performance includes: The coal-bio-heavy oil blend fuel 101 is burned in the thermal electric furnace 70 to form a combustion flame; High-speed camera 71 was used to capture images of the combustion flame of coal-bio-heavy oil blend fuel 101; The burning image is transmitted to computer 72, and the height and shape of the flame in the burning image are recorded.

[0056] For example, light source 73 can be used to illuminate the burning flame to take clearer pictures of the burning.

[0057] For example, the light source 73 is electrically connected to the computer 72, and the computer 72 can adjust the on / off state of the light source 73 or the brightness of the light source 73.

[0058] According to the combustion performance testing method of coal-bio-heavy oil blended fuel 101 of the present invention, by transmitting the combustion image to computer 72, the combustion flame height and morphology of coal-bio-heavy oil blended fuel 101 can be analyzed more accurately, and the combustion status of coal-bio-heavy oil blended fuel 101 can be judged more accurately.

[0059] The preparation method and combustion performance testing method of the coal-bio-heavy oil blended fuel 101 according to embodiments of the present invention are described below with reference to some specific examples.

[0060] I. Preparation of Coal-Bio-Heavy Oil Blended Fuel 101 Example 1: Coal powder (300 mesh sieve, calorific value 26.1 MJ·kg⁻¹, sulfur content 0.625%, nitrogen content 1.16%, oxygen content 9.676%, moisture content 3.39%, ash content 14.04%, volatile matter 30.23%, fixed carbon 52.34%) and bio-heavy oil (38.3 MJ·kg⁻¹, sulfur content 0.073%, nitrogen content 0.18%, oxygen content 11.005%, moisture content 0.49%, ash content 1.61%, volatile matter 96.93%, fixed carbon 0.97%) were mixed at a mass ratio of 1:1, with a total mixed mass of 1 g. The coal powder and bio-heavy oil were thoroughly ground in a mortar to form a homogeneous slurry, which was then dried at 120°C for 24 h.

[0061] Example 2: Coal powder and bio-heavy oil from the same source as in Example 1 were selected, with a coal powder to bio-heavy oil mass ratio of 1:4 and a total mass of 1 g after mixing. The mixture was thoroughly ground in a mortar to obtain a blended fuel slurry, which was then dried at 110°C for 20 h.

[0062] Example 3 The coal powder and bio-heavy oil of the same source as in Example 1 were selected, and the mass ratio of the coal powder to the bio-heavy oil was 4:1. After mixing, the total mass was 1 g. The blended fuel slurry was prepared by grinding in a mortar. Subsequently, the blended fuel slurry was dried at 105 °C for 20 h.

[0063] Comparative Example 1 The coal powder and microalgae of the same source as in Example 1 were selected, and the microalgae had a calorific value of 8.03 MJ·kg-1. After the microalgae were pulverized into powder, the microalgae powder was mixed with the bituminous coal at a mass ratio of 1:1, and the total mass of the mixture was 1 g. The blended fuel was prepared by grinding in a mortar. Subsequently, the blended fuel was dried at 120 °C for 24 h.

[0064] Comparative Example 2 The microalgae of the same source as in Comparative Example 1 were selected.

[0065] Comparative Example 3 The coal powder of the same source as in Example 1 was selected.

[0066] Comparative Example 4 The bio-heavy oil of the same source as in Example 1 was selected.

[0067] II. Test of combustion performance of coal-bio-heavy oil blended fuel 101 (1) Calorific value analysis Referring to Figure 1 The calorific values of Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 3 were analyzed.

[0068] The calorific value of Example 1 before drying was 29.8 MJ·kg⁻ 1 , and after drying, it increased to 32.1 MJ·kg⁻ 1 , which was higher than the calorific value of Comparative Example 3. This indicates that a moderate reduction in water content can significantly increase the effective calorific value.

[0069] The calorific value of Example 2 before drying was 32.2 MJ·kg -1 , and after drying, it increased to 34.7 MJ·kg -1 , which was significantly higher than the calorific value of Example 1, 32.1 MJ·kg -1 . The data shows that the higher the proportion of bio-heavy oil, the higher the overall calorific value of the fuel.

[0070] The calorific value of Example 3 before drying was 26.8 MJ·kg -1 , and after drying, it increased to 28.9 MJ·kg -1 , which was higher than the calorific value of Comparative Example 3, 28.1 MJ·kg -1but lower than the calorific value 32.1 MJ·kg of Example 1 -1 The results show that even if the low blending ratio of bio-oil is used, the fuel calorific value can be effectively improved, and the drying treatment is also significant for improving the effective calorific value.

[0071] The calorific value of Comparative Example 1 is 15.2 MJ·kg -1 , which is significantly lower than the calorific value 32.1 MJ·kg of Example 1 -1 , indicating that the energy density of microalgae is low. The calorific value of Comparative Example 3 is 28.1 MJ·kg -1 , indicating that the calorific value of pure coal is low, and the energy density is low.

[0072] (2) Combustion flame test The combustion performance of Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 was evaluated. The ignition was achieved by using a resistance wire, and the process was divided into three stages: ignition, stable combustion and decay combustion.

[0073] The experimental results show that the flame height and brightness are in the order of Comparative Example 3 < Example 1 < Comparative Example 4; the black smoke concentration decreases in the opposite direction. It is shown that the bio-oil is rich in oxidized functional groups, which can promote the ignition and burnout process, and enhance the combustion reactivity of bituminous coal.

[0074] Example 2 burns rapidly, with bright and stable flame and little black smoke, indicating that increasing the content of bio-oil can improve the combustion efficiency and burnout speed.

[0075] The flame height and brightness of Example 3 are significantly higher than those of Comparative Example 3, but slightly lower than those of Example 1, and the black smoke generation is significantly reduced compared with Comparative Example 2, indicating that even a small amount of bio-oil can improve the combustion efficiency and burnout speed.

[0076] The combustion of Comparative Example 1 is unstable, difficult to ignite, with low flame height, and the combustion is accompanied by obvious black smoke and weak brightness. The flame height and brightness of Comparative Example 1 are slightly higher than those of Comparative Example 2, but lower than those of Example 1, and the black smoke concentration is large, indicating that microalgae is not conducive to promoting ignition and stable combustion.

[0077] (3) Combustion characteristic test Thermogravimetric analysis (TG-DTG) test and residue analysis were performed on Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4.

[0078] The thermogravimetric analysis (TG-DTG) results show that the pyrolysis interval of Comparative Example 2 is 300-600°C, and the main combustion temperature is 532°C; the pyrolysis interval of Comparative Example 3 is 250-520°C, and the main peak temperature is 343°C, 362°C and 416°C.

[0079] The DTG curve of Example 1 is closer to Comparative Example 4, with slightly lower peaks, and the combustion process is dominated by bio-heavy oil; the DTG curve of Comparative Example 4 is high and narrow, with concentrated release, which is conducive to ignition. Residue analysis shows that the residual amount of bituminous coal in Comparative Example 3 is 13.9%, while that in Example 1 is only 0.01%, and Example 1 significantly improves the burnout rate and energy utilization efficiency compared with Comparative Example 3.

[0080] The DTG curve of Example 2 is closer to Comparative Example 4, with main pyrolysis peaks occurring between 350 and 470°C, with peak temperatures of 340°C, 358°C and 410°C, respectively, indicating that the combustion process is obviously dominated by bio-heavy oil, with concentrated and strong heat release. Residue analysis shows that the residual amount of Example 2 is as low as 0.005%, indicating that the combustion is complete.

[0081] The pyrolysis characteristics of Example 3 are dominated by bituminous coal, with a pyrolysis range of 300-580°C, and a main combustion peak at about 523°C, but a small pre-peak (about 410°C) can be observed, which is related to the volatile pyrolysis of bio-heavy oil. The DTG curve shows a wider peak shape and a more dispersed heat release process. Residue rate analysis shows that the residue content of Example 3 after combustion is 7.2%, which is much lower than that of Comparative Example 3 (13.9%), but slightly higher than that of Example 1 (0.01%), indicating that part of the bio-heavy oil can still improve the burnout degree of coal.

[0082] The pyrolysis range of Comparative Example 2 is 220-470°C, with a main peak at 340°C, and the curve is wide and slow, with a dispersed release process. The DTG curve of Comparative Example 1 shows a double-peak shape, corresponding to the pyrolysis process of microalgae and bituminous coal, with peak temperatures of 345°C and 518°C, respectively, with non-concentrated release, making it difficult to form stable combustion. Residue rate analysis shows that the residue rate of Comparative Example 1 is 8.7%, which is much higher than that of Example 1 (0.01%), indicating that the combustion is not complete and the fuel utilization efficiency is low.

[0083] (4) Pollutant emission analysis Examples 1, 2, 3, Comparative Examples 1, 2, 3 and 4 were burned at a combustion temperature of from room temperature to 1100°C, with a heating rate of 10°C·min-1, and the emissions of SO2 and NO2 were monitored using an online flue gas analysis platform, and the release content of gaseous products during combustion was analyzed using a thermogravimetric-mass spectrometry (TG-MS) analysis platform.

[0084] The monitoring results show that the concentration of SO2 emitted after combustion of Example 1 is only 151 ppm, and the concentration of NO2 is only 18 ppm. Thermogravimetric-mass spectrometry (TG-MS) analysis shows that the release content of main gaseous products during combustion of Example 1 follows the order CO>CO2>NO>SO2>NO2, and the release content of NO is much higher than that of SO2, which is consistent with the fact that the combustion process is dominated by bio-heavy oil. xThe overall emission level of SO2 is low, which reflects the advantage of the coal-bio-heavy oil mixed combustion system in environmental friendliness.

[0085] The emission concentration of SO2 in the combustion process of Example 2 is only 86 ppm, and the detection of NO2 is 9 ppm, which is far lower than the emission level of traditional coal fuel. TG-MS shows that the main products are still CO>CO2>NO>SO2>NO2, the emission is clean, and meets the green fuel standard. Compared with Example 1, the pollutant emission does not increase significantly, which shows that the high mixing ratio still has good environmental protection performance.

[0086] The emission concentration of SO2 in the combustion process of Example 3 is only 237 ppm; the concentration of NO2 is 26 ppm. The thermal gravimetric-mass spectrometry analysis (TG-MS) further shows that the main gaseous products released in the combustion process of Example 3 still follow the rule of CO>CO2>NO>SO2>NO2. Although the emissions of NO x and SO2 increase slightly due to the increase of coal ratio, the overall emission level is low, which shows good clean emission effect.

[0087] The emission concentration of SO2 in the combustion process of Comparative Example 1 reaches 305 ppm, and the concentration of NO2 is 89 ppm, which are significantly higher than the corresponding emissions (151 ppm and 18 ppm) of the 1:1 bituminous coal-bio-heavy oil mixed fuel. It is believed that the relatively high nitrogen content in microalgae is the main reason for the increase of NO x emission, and its incomplete combustion also increases the release of SO2. The above data show that the combustion performance and environmental protection performance of microalgae in the blended fuel are not as ideal as bio-heavy oil.

[0088] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0089] In the description of the present application, "first feature" and "second feature" can include one or more features.

[0090] In the description of the present application, "a plurality of" means two or more.

[0091] In the description of the application, a first feature being "on", "above", or "on top" of a second feature can include the first and second features being directly in contact, or the first and second features not being directly in contact but being in contact through another feature between them.

[0092] In the description of the application, a first feature being "on", "above", and "on top" of a second feature includes the first feature being directly on, above, and on top of the second feature, or just means the first feature being horizontally higher than the second feature.

[0093] In the description of the application, the description of the reference terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the application. In the description of the application, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0094] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and alterations can be made hereto without departing from the principles and spirit of the application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for preparing a coal-bio-heavy oil blended fuel, characterized in that, include: Mix pulverized coal and bio-heavy oil evenly according to the set mass ratio; The mixture of pulverized coal and bio-heavy oil is dried at a set temperature for a set time to form a coal-bio-heavy oil blended fuel.

2. The method for preparing coal-bio-heavy oil blended fuel according to claim 1, characterized in that, The particle size of the pulverized coal is 200-300 mesh; And / or, the bio-heavy oil is a liquid by-product oil, and the sulfur content of the bio-heavy oil is <0.01%.

3. The method for preparing coal-bio-heavy oil blended fuel according to claim 1, characterized in that, The set mass ratio is any one of 9:1, 4:1, 7:3, 3:2, 1:1, 2:3, 3:7, 1:4, and 1:

9.

4. The method for preparing coal-bio-heavy oil blended fuel according to claim 1, characterized in that, Before drying the mixture of coal powder and bio-heavy oil, it is ground in a mortar and pestle to form a slurry.

5. The method for preparing coal-bio-heavy oil blended fuel according to claim 1, characterized in that, The set temperature is 100-160°C, and the set time is 12-24h.

6. A coal-bio-heavy oil blended fuel, characterized in that, The coal-bio-heavy oil blended fuel is prepared by any one of the methods described in 1-5.

7. A method for testing the combustion performance of a coal-bio-heavy oil blended fuel, characterized in that, The coal-bio-heavy oil blended fuel is the coal-bio-heavy oil blended fuel according to claim 6, and the combustion performance test method of the coal-bio-heavy oil blended fuel includes: The coal-bio-heavy oil blend fuel is ignited using resistance wire ignition in an air atmosphere. The pollutant emissions of the coal-bio-heavy oil blended fuel were monitored using an online flue gas analysis platform.

8. A combustion performance testing device for a coal-bio-heavy oil blended fuel, characterized in that, The combustion performance testing equipment is used in the combustion performance testing method according to claim 7, and the combustion performance testing equipment includes: Compressed air cylinders; A tubular furnace assembly includes a tubular furnace and a test tube, wherein the test tube is disposed in the tubular furnace, at least a portion of the test tube is located inside the tubular furnace, the test tube has an air inlet and an air outlet, the air inlet is connected to a compressed air cylinder via a first connecting pipe, and a gas flow meter is provided on the first connecting pipe; A flue gas analyzer includes a gas inlet and a gas outlet, wherein the gas inlet and the gas outlet are connected by a second connecting pipe, and a pressure gauge is provided on the second connecting pipe; A condenser containing a cooling medium, wherein at least a portion of the second connecting pipe is located inside the condenser and in contact with the cooling medium.

9. A method for testing the combustion performance of a coal-bio-heavy oil blended fuel, characterized in that, The coal-bio-heavy oil blended fuel is the coal-bio-heavy oil blended fuel according to claim 6, and the combustion performance testing method includes: testing the pyrolysis process of the coal-bio-heavy oil blended fuel using a thermogravimetric analyzer and a thermogravimetric-mass spectrometer, respectively.

10. A method for testing the combustion performance of a coal-bio-heavy oil blended fuel, characterized in that, The coal-bio-heavy oil blended fuel is the coal-bio-heavy oil blended fuel according to claim 6, and the combustion performance testing method includes: The coal-bio-heavy oil blended fuel is burned in a thermal electric furnace to form a combustion flame; High-speed cameras were used to capture images of the combustion flame of the coal-bio-heavy oil blend fuel; The burning image is transmitted to a computer, and the height and shape of the flame in the burning image are recorded.

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