| In recent years,with the rapid economic development in China,the demand for coal has increased greatly,and the coal transportation has become the main way to solve the problem of coal resource imbalance caused by the geographical differences in coal storage energy.As the coal production increases rapidly,many problems including occupational diseases like pneumoconiosis and lung disease,environmental pollution,economic losses which are caused by coal dust during the process of mining,transportation and storage will need to be solved.The traditional methods to control open-air coal dust mainly include water sprinkles,tarpaulins,nets and traditional dust suppressors,but they are gradually eliminated by the market because of many disadvantages,for instance,they are non-biodegradable which lead to soil pollution and have short duration and less effect in dust suppression.Under the help of science and technology with continuous progress,a variety of new chemical dust inhibitors have been rapidly developed by researchers and then applied to control the coal dust.At present,the commonly used chemical dust suppressors in the market are the polymer chemical dust suppressor,the high-fold absorbent resin chemical dust suppressor,the mucous the membrane chemical dust suppressor and so on.Compared with the traditional dust suppressor,they are more effective,but there are some disadvantages for them.For example,the polymer is difficult to degrade and its cost is also high;The curing layer after film formation is so brittle that it is easily cracked by vibration and strong wind;What's more,it is difficult to control the microcoal dust.Therefore,it is important to study and develop eco-friendly suppressors which are not only inexpensive,more effective but also biodegradable on the level of practice.This paper chooses nanocellulose extracted from peanut shell as the main material because of its wide range of source and low cost and dimethyl diethylene acrylonic acid chloride(DMDAAC),N,N'-methyl biacrylamide(MBA),acrylacid(AA)and acryl triolas as the auxiliary material,using aqueous solution polymerization method to prepare a new kind of biodegradable nanocellulose dust suppressor.The experiment mainly studied the extraction process of nanocellulose and the preparation process of new degradable nanocellulose dust suppressant.Through the use of pH and viscosity experiments,surface tension experiments,solid content determination experiments,Fourier infrared spectrometer(FTIR),thermogravimetric analyzer and industrial analysis,the nature of the dust suppressant itself was studied in detail.The performance of the dust suppressant was studied through contact angle experiment,permeability experiment,scanning electron microscope experiment,wind resistance performance experiment and evaporation resistance experiment.Through single-factor experiments,the main factors(coal dust particle size,ambient temperature,wind speed,dust suppressant solution concentration)and their interactions were studied,and an open-air transportation dust suppression simulation experiment was carried out to Simulate the dust suppression process on site.The main research conclusions of this article are as follows:(1)The extraction of nanocellulose from peanut shells by acid solution:The peanut shell cellulose is made with the solution of sodium hypochlorite with a mass concentration of 1.7%at the solid liquid ratio of 1:15,and then by adding sulfuric acid with a mass score of 30%,the nanocellulose powder is prepared through centrifugation,dialysis,vacuum freezing and other processes.It is added to 15%nitric acid solution to activate it.After fully dissolving NCC at75?,a small amount of potassium persulphate is added into the solution consisting of NCC solution,AA and DMDAAC in terms of the ratio of 10:5:6and stirred to make them reaction.Finally,through adding MBA and propylene triol,a new kind of biodegradable nanocellulose dust inhibitor is prepared until they have reaction.(2)The pH of the anti-duster solution with a concentration of 5%at a temperature of 25?is 6.31,and its viscosity which is 70.3 mPa·s is much greater than that of water(1mPa·s)and is conducive to bonding the coal dust.The surface tension value is 33.66 m N·m-1 and it is less than the surface tension of water 72.9 m N·m-1,which improves the wetting capacity of water.The solid content of the dust suppressor is 32.1%and its dilution multiples can be increased in practical applications.So it has the advantage of saving costs.By infrared spectroscopy,the absorption peak near 875 cm-1 and 896 cm-1 is the characteristic peak of glycoside bond?-1,4 in fibrous diglysemic,thus the three-dimensional mesh structure of nanocellulose is preserved.In the infrared spectrum of dust suppressant,RCOO-symmetric stretching vibration absorption peak and C=O stretching vibration absorption peak in carboxyl group appear at1640 cm-1 and 1721 cm-1,respectively.It shows that the connection polymerization reaction have completed.According to comprehensive thermal,it shows that the dust suppressor has the good stability as it begins to decompose at 201.1?,thus it is better well-preserved.By analyzing the industrial samples of coal sprayed the dust suppressor and raw coal,it is concluded that the dust suppressor has no effect on coal quality.(3)The contact angle between the dust suppressor and the coal sample is measured at 34°.The dust suppressor has a penetration depth that is up to 7.4 cm within three hours.Through the scanning electron mirror experiment,it can be seen that the surface of the coal dust that is sprayed with the dust suppressor is dense and is bonded to different coal dust particles,forming a stable curing layer.The coal sample sprayed the dust suppressor can still effectively suppress coal dust at the wind speed of 20 m/s and the temperature of 50?.(4)Through the monomer experiment,the paper studies the coal dust particle size,ambient temperature,wind speed,dust suppressor solution concentration and mainly factors affecting the effect of dust suppression.This paper also determines the optimal process parameters of the dust suppressor when it is sprayed through the coal dust concentration as the response value after the study of response surface experiment which studies the interaction of various factors and the two methods of visual analysis and variance analysis.Its optimal process parameters are that the ambient temperature is 25?,the wind speed is m/s and the dust suppressor solution concentration is 5%.(5)By designing the simulation experiment of open-air transportation dust suppression,the performance of the dust suppressor in transportation is simulated.By the wind resistance experiment,the coal dust concentration of the experimental group is much lower than that of the control group both in whole dust and dust call edgy.For example,when the wind speed is 12 m/s,the total dust ratio of the experimental group is reduced by 90.3%and its dust-calling ratio is reduced by 91.5%compared with those of the control group respectively.At the temperature of 32?,the loss rate of coal samples sprayed with anti-dust solution is only 0.36%after six hours.In 15 days'continuous experiment,the curing layer of the model surface sprayed the dust suppressor is stronger than that of the surface formed by spraying water,which is better to suppresst coal dust. |
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