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Environmental and Working Area Dust Emission from the Gypsum Warehouse
Available online at www.sciencedirect.com
ScienceDirect Procedia Engineering 150 (2016) 2080 – 2086
International Conference on Industrial Engineering, ICIE 2016
Environmental and Working Area Dust Emission from the Gypsum Warehouse A.V. Azarov*, N.S. Zhukova, E.A. Kalyuzhina Volgograd State University of Architecture and Civil Engineering, 1, Akademicheskaya Str., Volgograd, 400074, Russia
Abstract The work analyses the emissions analysis for gypsum binder production. The major air pollutant is the suspended solids composed of a mixture of particles in air, which can be either solid or liquid and be a complex mixture of organic and inorganic substances. Studies have shown that excessive concentrations of inorganic dust (gypsum dust) generated by the open gypsum warehouse storage and thus the contribution of emission sources into total concentration of inorganic dust (dust plaster) average vary from 66,28% to 87,67%. The highest excessive concentrations of inorganic dust are registered at the border of regulated areas: up to 20% SiO2 (plaster dust) (from 5,9 to 16,0 shares of maximum allowable concentration (MAC)). © 2016The TheAuthors. Authors.Published Published Elsevier © 2016 by by Elsevier Ltd.Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of ICIE 2016. Peer-review under responsibility of the organizing committee of ICIE 2016 Keywords: disperse composition of dust; plaster dust mass concentration of particulate matter; warehouse storage of gypsum.
1. Experimental research of the plaster dust inflation from the storage warehouse Research object of the content of gypsum spray in the air is public warehouse storage of pre-crushed gypsum rock, where sampling on the borders of the site of the warehouse was carried out. Unloading of crushed gypsum rock from belt conveyor to the gypsum stone storage warehouse is made by means of a mobile drum dumped trolleys installed in the unloading areas, which is accompanied by dust emission into the atmosphere. The amount of gypsum transshipped through piles - 1200000 t/y, download performance of gypsum stone in each shoulder through hard truck resets - 240 t/h; shoulder height of the cone 17 m, footprint shoulder – 5200 m2 and 1000 m2. At the same time
* Corresponding author. Tel.: +7-968-283-80-00 E-mail address: [email protected]
1877-7058 © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of ICIE 2016
doi:10.1016/j.proeng.2016.07.242
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in the outdoor gypsum storage arrives 7,16 t/h of gypsum dust fraction 0 ȝm - 235 ȝm, 2,93 t/h of gypsum dust fraction 0 ȝm - 102 ȝm (at 4000 hours per year of the enterprise). To reduce the negative impact of fugitive emissions sources in the ambient air at the enterprises which produce gypsum binders and process gypsum raw researches of gypsum dust content in ambient air (aerosol) were carried out [1-6]. Analysis of the dust dispersed composition of each resultant samples was performed using the software "Dust 1" [7]. The results showed that the value of the diameter of the dust particles contained in air in the informal source location area can be up to 105 ȝm. Range median diameter d50 values is ranging from 12 ȝm to 51 ȝm, in most cases, this value is close to 20 ȝm in connection with which one can conclude high content in the ambient air near the unorganized source of gypsum dust particles not only relatively small size (up 10 ȝm), but even large from 10 ȝm to 50 ȝm [8-17]. To calculate the fugitive emissions from warehouses (tail-end) storage of dusty materials in the building materials industry the following formula was used [18]:
Ems
K 4 K5 K 6 K7 q Fwork K 4 K5 K6 K 7 0,11q Fdust Fwork 1 K ;
(1)
E ye
0,11 8, 64 102 K 4 K 5 K 6 K 7 q Fwork 1 K T Tr Ts ;
(2)
where Ems - specific emission into the atmosphere of harmful substances (dust) during storage of the material process, g/s; Eye - gross emission of pollutants (dust) during storage process of the material, t/year; K4, K5, K6, K7 coefficients taking into account the type of storage (open/closed space), humidity of the material, surface profile of the stored material, size of the material; Fdust, Fmax, Fwork - dusting surface areas, actual size of the maximum level, filling of the area on which handling operations take place; q - specific dust blowing out, g/(m2·s); T - total storage time of material in the considered period, days; Ɍr – number of rainy days; Ɍs – number of days with steady snow cover. For a more accurate calculations of dust emissions from each type of storage of static storage in the gypsum production and a more accurate assessment of environmental pollution fugitive emissions, depending on the specific content of dust fractions (kg/m3), disperse composition of dust fractions (d5, d50, d95) specific dust blowing out q mg/ (m2·s) from the volume of the rock gypsum, selected at landing sites on the open warehouse storage was investigated, which is determined by the formula [18]:
q
a vb
(3)
where q - specific dust blowing out mg/(m2·s); v - wind speed, m/s; a and b - empirical coefficients, depending on the type of overloaded material [18]. According to [19] specific dust blowing out, g/(m2·s), depending on the wind speed (m/s) and acting on the open storage of bulk materials warehouses obeys power law and also coefficients a and b were obtained to determine the dust emission from the surface for different materials. Researches of specific dust blowing out q from the rock gypsum volume, selected in place of discharge of the outdoor storage warehouse were carried out in an experimental wind tunnel, which simulates the effect of wind loading on the means of creating air artificial uniform rectilinear in the working section airflow. Wind tunnel experiments were based on the principle of reversibility of motion when movement of the air flow impinges on a fixed element. General view of the wind tunnel is shown on Fig. 1. During experimental studies suspended volume of soil (Vconv = 0,02 m3) which has a pre-measured value of the mass of sample plaster dust sifted through a sieve with a mesh size of 0,125 mm, was placed in a wind tunnel. The task of the first stage of the research was to determine a and b coefficients with exponential function q(v). In the course of this phase three types of rock mass were used: N1 – Spc = 11,75 kg/m3; N2 – Spc = 6,06 kg/m3; N3 – Spc = 2,31 kg/m3. The first type of gypsum raw material corresponds by characteristics to the mass stored in the open warehouse storage of investigated enterprise. During the research each type of raw material masses was affected by air flow at different speeds (v1 Ĭ 1 m/s; v2 Ĭ 2 m/s; v3 Ĭ 3 m/s, …, v10 Ĭ 10 m/s). During each test feedstock rate
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changed sequentially, the value of the dust mass (mg) in each experiment were summed with previous value. Thus, one error was eliminated whish affected statistical correlation of experimental results.
Fig. 1 - General view of a wind tunnel
The results, determining the specific surface blowing out from the surface of the gypsum raw materials warehouse are shown in Table 1. Table 1. Parameters defining specific blowing out from the surface of the gypsum raw materials warehouse for three types of specific content of dust fractions (kg/m3). ʋ
Name of raw materials
Characteristics of raw materials Spc, kg/m3
1
Gypsum Rock 0-50 mm Gypsum Rock 0-50 mm Gypsum Rock 0-50 mm
2 3
Parameters of the power model a
b
11,75
0,004
3,958
6,05
0,003
3,673
2,31
0,001
3,839
Calculation was made by the formulas (1) and (2) of the amount of inorganic to 20% dust emission SiO2 (gypsum dust) under static storage materials according to the characteristics previously adopted in the calculations with a and b coefficients for chalk (K4 = 1; K5 = 0,1, K6 = 0,25, Ʉ7=0,5; Fwork = 120000 m2; Fdust = 120000 m2; Ș = 0; T = 365 d.; Ɍr = 101 d.; Ɍs = 80 d.;v = 8,1 m/s): 1. Spc = 11,75 kg/m3; q = 15,77 mg/(m2·s); Ems = 23,65 g/s; Eye = 41,36 t/y. 2. Spc = 6,05 kg/m3; q = 6,51 mg/(m2·s); Ems = 9,77 g/s; Eye = 17,09 t/y. 3. Spc = 2,31 kg/m3; q = 3,07 mg/(m2·s); Ems = 4,61 g/s; Eye = 8,06 t/y. Comparison of the results of calculations with the data obtained using the coefficients a and b for chalk for any specific values of dust blowing out determined experimentally for gypsum dust are shown on Fig. 2. As can be seen on the histogram divergence values previously obtained quantity of emissions calculations (for those in [18] coefficients a and b for chalk) with the results of a regression model based on the results of the experiment is about 50%. Significant percentage differences in the results is associated with high gypsum dust fractions in the mass of rock in the open warehouse storage of gypsum raw materials, i.e. the impact of fugitive emissions of the enterprise on the environment and regulated areas initially set wryly [20]. In addition, the difference between the values of emissions while extent of the specific content of the gypsum dust in the test volume of 2,31 kg/m3 to 11,75 kg/m3 is 50-80%, indicating the need for clarification of the formula (3), however, in accordance with the results obtained in the second stage of the research, the task of which was to produce a mathematical model of the resultant index q (mg/ (m2·s)) from independent variables v (m/s) and Spc (kg /m3) of particulate analysis of dust samples weathered from mass investigated for its aerodynamic properties and their evaluation according to the speed v (m/s).
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Fig. 2. Histogram with grouped assess of calculations results of emissions from the warehouse for gypsum raw material at different values of specific dust blowing out mg / (m2 · s)
Past studies of dependence between specific dust blowing out, with the characteristics of the particulate composition of weathered dust from the wind speed and dust proportion showed that the particle diameter d5 ranges from 4 to 35 ȝm, d50 - 7 to 78 ȝm, d95 - from 12 to 92 ȝm. The values of the characteristics of integral distribution functions of the mass particle over diameters, namely d5, d50, d95 of dust weathered from the test mass of the gypsum raw material at various air speeds are shown on Fig. 3.
Fig. 3. Integral function mass distribution of dust particle over diameters in logarithmic likelihood-grid for dust samples from the weathered studied weight gypsum raw material at different air speeds v (m/s):1) 1,2 - 1,6 m/s; 2) 2,2 - 2,4 m/s; 3) 4,1 - 4,9 m/s; 4) 5,3 - 5,9 m/s; 5) 7,0 - 7,9 m/s; 6) 8,4 - 8,6 m/s; 7) 9,1 - 9,6 m/s; 8) 10,3 - 10,5 m/s; 9) 11,2 - 11,7 m/s; 10) 12,0 - 12,3 m/s
Construction of the base regression models was performed in an integrated system analysis and data management - STATISTICA Advanced Linear/Nonlinear Models (recessed linear/non-linear model) [21, 22, 23]. As a form of a mathematical model exponential growth ( y c exp b0 b1 x1 b2 x2 ) was taken as ratio between the studied variables at the beginning of the research which is very different from the ratio in the final levels of independent variables, that is, in the preformed pattern (figure experimental studies values) of the point with maximum curvature and smoothness leave up, which is clearly faster than the linear and power function. As the error
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function method of least squares is used. The method of assessing the adequacy of the mathematical model quasiNewton method was selected. Shows received adequate mathematical model specific dust blowing out, q, mg/(m2·s):
q v, Sɪɫ
4,93752 exp 0, 068983 0, 233714v 0,112124Sɪɫ ;
(4)
Figure 4 shows the response surface constructed from the dust blowing out resulting mathematical model. Diagram shows that a sharp increase in the weathering values (dust gypsum blowing out) occurs with increasing air flow rate of more than 6 m/s and an increase in levels of dust fractions of more than 7 kg/m3, while the level of dust content of less than 7 kg/m3 change in the surface values response has a smooth character.
Fig. 4. Figure specific surface response dust blowing out, q depending on the levels of specific combinations of gypsum dust content in the test volume Spc and air flow rate v
According to [24] researches of sedimentation rate of the particles contained in the plaster dust obtained sample weights (10 composite samples) during the research of dependence of the specific dust blowing out from the air flow rate and the specific content of dust fractions in the rock mass were conducted. The studies established, intervals settling dust fractions, obtained values of sedimentation velocity (Table 2). The results of the gypsum particles settling studies were constructed based on the equivalent settling velocity of the particle diameter in logarithmic grid (Fig. 5).
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The resulting dependence of the rate of subsidence of the equivalent diameter of the particles, allow us to offer a formula for determining the rate of sedimentation of dust particles contained in the rock mass in the open warehouse storage of raw materials.
vs
A e Bd ;
(5)
or ln vs
ln A Bd ;
(6)
where vs - dust particle settling velocity, m/s; d - equivalent diameter of the particles of dust; A, B - factors that characterize the type of dust. Table 2. Characterization of dust fractions obtained in the study of specific dust blowing out. Gap subsidence, s
Features of the particulate composition, ȝm
Sedimentation speed, m/s
d5
bottom line
d50
d95
upper bound
1-2
35
78
92
1,2
2,5
2-3
30
71
91
0,6
1,2
3-4
29
60
81
0,4
0,6
4-5
24
51
70
0,3
0,4
5-6
19
41
60
0,24
0,3
6-30
16
36
50
0,2
0,24
30-60
9
20
26
0,04
0,2
60-120
6
16
21
0,02
0,04
120-300
5
10
13
0,01
0,02
Ȼɨɥɟɟ 300
4
7
12
-
0,01
Fig.5. The dependence of the sedimentation rate of the equivalent diameter of the particles in the logarithmic grid: d5 - minimum equivalent diameter; d50 - median equivalent diameter; d95 - maximum equivalent diameters.
2. Conclusion The specific content of dust fractions Spc (kg/m3) was determined based on the weight fraction of plaster dust able to extend beyond the boundaries of open gypsum storage warehouse 0-105 ȝm (maximum particle diameter of the fixed boundaries of the warehouse).
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Handled studies of sedimentation rate depending on the equivalent diameter of the dust particles, led to the conclusion that when sedimentation rate 1,2 - 2,5 m/s particles have maximum size of 92 ȝm, median size of 78 ȝm and minimum size 35 ȝm. When settling rate of less than 0,01 m/s particles have a maximum size of 12 ȝm, median size of 7 ȝm and minimum size of 4 ȝm. According to the results of analytical and experimental studies of the mathematical model (regression equation) for determination of the specific plaster dust blowing out stored in the open air, depending on the air flow rate and the content of dust in the rock mass. Studies have shown that the fine dust content exceeds established on the border of regulated areas for inorganic dust up to 20% SiO2 (plaster dust) (5,9 to 16,0 shares of MAC), which leads to the deterioration of sanitary conditions in the plant, on the borders of the sanitary protection zone (SPZ) for regulated areas, and also leads to loss of gypsum raw materials. References [1] A.V. Azarov, A.B. Strelyaeva, N.A. Marinin, The significance of the particulate composition of dust in technological processes, Internet Journal of VolgGASU. 28 (2013). [2] V.N. Azarov, N.A. Marinin, R.A. Burkhanova, A.V. Azarov, About composition of the dust dispersed in the air during materialproduction, Bulletin of Volgograd State University of Architecture and Civil Engineering, Series: Construction and architecture. 30 (2013) 256260. [3] V.N. Azarov, N.A. Marinin, N.S. Barikaeva, T.N. Lopatina, About air pollution by fine-dispersed dust in urban areas, Biosphere compatibility: people, region, technology. 1 (2013) 3034. [4] A.B. Strelyaeva, N.S. Barikaeva, E.A. Kalyuzhina, D.A. Nikolenko, Analysis of air pollution sources by fine-dispersed dust, Internet Journal VolgGASU. 34 (2014). [5] V.N. Azarov, I.V. Tertishnikov, E.A. Kalyuzhina, N.A. Marinin, An estimate of the concentration of fine-dispersed dust (ɊɆ10 ɢ ɊɆ2,5) in the air, Bulletin of Volgograd State University of Architecture and Civil Engineering, Series: Construction and architecture. 25 (2011) 402 406. [6] N.S. Barikaeva, A.B. Strelyaeva, R.V. Orlov, Estimation of suspended particles PM10 and PM2,5 in the air of residential areas, International Journal of Alternative Energy and Ecology. 134 (2013) 3941. [7] V.N. Azarov, A.V. Azarov, RU Certificate of the state registration of computer program 2014618468. (2014). [8] V.N. Azarov, E.Y. Esin, N.V. Azarov, The analysis of the dust composition dispersed in the technosphere, Tutorial, Federal Agency for Education of Russian Federation, Volgograd State University of Architecture and Civil Engineering,Volgograd, 2008. [9] V.N. Azarov, N.M. Sergina, Methods of microscopic analysis of particulate dust composition using PC, deposited the manuscript 1332V2002, 2002. [10] V.N. Azarov, Improving dusty environment assessment and implement measures to reduce dusty air at working and sanitary protection zones of industrial enterprises, Dr. diss., Rostov-on-Don, 2003. [11] V.N. Azarov, V.Yu. Yurkyan, N.M. Sergina, A.V. Kovalev, Methods of microscopic analysis of disperse composition of dust using a personal computer (PC), Legislative and applied metrology. 1 (2004) 4648. [12] V.N. Azarov, N.A. Marinin, D.A. Zhogoleva, On an estimate of the concentration of fine dust (PM10 and PM2,5) in the atmosphere of cities, Proceedings of South-Western State University. 38 (2011) 144149. [13] Technique of microscopic analysis of disperse dust composition using a personal computer (PC), The list of methods of measurements of concentrations of pollutants in the emissions of the industrial enterprises, approved for use in 2014, SRI Atmosphere, St. Petersburg, 2013. [14] Particle image processing program DUST 1: the testimony of the state. reg. computer software DUST 1, 2014. [15] V.N. Azarov, S.A. Koshkarev, M.A. Nikolenko, Systems abatement dedusting using particulate dust analysis in the construction industry, Engineering Don bulletin. 34 (2015). [16] N.S. Ponomareva, About chalk dust concentration in the air of working zones and emissions into the atmosphere at the enterprises construction industry, Bulletin of Volgograd State University of Architecture and Civil Engineering, Series: Construction and architecture. 20 (2010) 9398. [17] V.N. Azarov O.V. Yurkyan, N.M. Sergina, Methods of microscopic analysis of disperse dust composition using a personal computer (PC), Legal and applied metrology. 1 (2004) 4648. [18] Guidelines for calculation of emissions from fugitive sources in the building materials industry, NIPIOTSTROM, Novorossiysk, 2001. [19] A.I. Loboda, V.Y. Tyschuk, Influence of waste dumps on the dustiness of the atmosphere and ways of its normalization, Safety in the mining industry: industry. thematic collection, Minchermeta. (1986) 4751. [20] T.V. Doncova, S.S. Hrapov, V.N. Azarov, About modeling of transport pollutant dynamics in the atmosphere of cities, International Journal of Alternative Energy and Ecology. 134 (2013) 6772. [21] V.N. Azarov, V.I. Boglaev, N.A. Marinin, Description of disperse composition of dust aspiration systems in the manufacture of gypsum, in: Proceeding of IX International Conference indoor air quality and the environment, VolgGASU, Volgograd. (2011) 8690. [22] H.J. Seltman, Experimental Design and Analysis, 2015. [23] R.O. Kuehl, Design of Experiments: Statistical Principles of Research Design and Analysis, 2nd Edition. [24] S.A. Koshkarev, US Patent 156520. (2015).
ScienceDirect Procedia Engineering 150 (2016) 2080 – 2086
International Conference on Industrial Engineering, ICIE 2016
Environmental and Working Area Dust Emission from the Gypsum Warehouse A.V. Azarov*, N.S. Zhukova, E.A. Kalyuzhina Volgograd State University of Architecture and Civil Engineering, 1, Akademicheskaya Str., Volgograd, 400074, Russia
Abstract The work analyses the emissions analysis for gypsum binder production. The major air pollutant is the suspended solids composed of a mixture of particles in air, which can be either solid or liquid and be a complex mixture of organic and inorganic substances. Studies have shown that excessive concentrations of inorganic dust (gypsum dust) generated by the open gypsum warehouse storage and thus the contribution of emission sources into total concentration of inorganic dust (dust plaster) average vary from 66,28% to 87,67%. The highest excessive concentrations of inorganic dust are registered at the border of regulated areas: up to 20% SiO2 (plaster dust) (from 5,9 to 16,0 shares of maximum allowable concentration (MAC)). © 2016The TheAuthors. Authors.Published Published Elsevier © 2016 by by Elsevier Ltd.Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of ICIE 2016. Peer-review under responsibility of the organizing committee of ICIE 2016 Keywords: disperse composition of dust; plaster dust mass concentration of particulate matter; warehouse storage of gypsum.
1. Experimental research of the plaster dust inflation from the storage warehouse Research object of the content of gypsum spray in the air is public warehouse storage of pre-crushed gypsum rock, where sampling on the borders of the site of the warehouse was carried out. Unloading of crushed gypsum rock from belt conveyor to the gypsum stone storage warehouse is made by means of a mobile drum dumped trolleys installed in the unloading areas, which is accompanied by dust emission into the atmosphere. The amount of gypsum transshipped through piles - 1200000 t/y, download performance of gypsum stone in each shoulder through hard truck resets - 240 t/h; shoulder height of the cone 17 m, footprint shoulder – 5200 m2 and 1000 m2. At the same time
* Corresponding author. Tel.: +7-968-283-80-00 E-mail address: [email protected]
1877-7058 © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of ICIE 2016
doi:10.1016/j.proeng.2016.07.242
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A.V. Azarov et al. / Procedia Engineering 150 (2016) 2080 – 2086
in the outdoor gypsum storage arrives 7,16 t/h of gypsum dust fraction 0 ȝm - 235 ȝm, 2,93 t/h of gypsum dust fraction 0 ȝm - 102 ȝm (at 4000 hours per year of the enterprise). To reduce the negative impact of fugitive emissions sources in the ambient air at the enterprises which produce gypsum binders and process gypsum raw researches of gypsum dust content in ambient air (aerosol) were carried out [1-6]. Analysis of the dust dispersed composition of each resultant samples was performed using the software "Dust 1" [7]. The results showed that the value of the diameter of the dust particles contained in air in the informal source location area can be up to 105 ȝm. Range median diameter d50 values is ranging from 12 ȝm to 51 ȝm, in most cases, this value is close to 20 ȝm in connection with which one can conclude high content in the ambient air near the unorganized source of gypsum dust particles not only relatively small size (up 10 ȝm), but even large from 10 ȝm to 50 ȝm [8-17]. To calculate the fugitive emissions from warehouses (tail-end) storage of dusty materials in the building materials industry the following formula was used [18]:
Ems
K 4 K5 K 6 K7 q Fwork K 4 K5 K6 K 7 0,11q Fdust Fwork 1 K ;
(1)
E ye
0,11 8, 64 102 K 4 K 5 K 6 K 7 q Fwork 1 K T Tr Ts ;
(2)
where Ems - specific emission into the atmosphere of harmful substances (dust) during storage of the material process, g/s; Eye - gross emission of pollutants (dust) during storage process of the material, t/year; K4, K5, K6, K7 coefficients taking into account the type of storage (open/closed space), humidity of the material, surface profile of the stored material, size of the material; Fdust, Fmax, Fwork - dusting surface areas, actual size of the maximum level, filling of the area on which handling operations take place; q - specific dust blowing out, g/(m2·s); T - total storage time of material in the considered period, days; Ɍr – number of rainy days; Ɍs – number of days with steady snow cover. For a more accurate calculations of dust emissions from each type of storage of static storage in the gypsum production and a more accurate assessment of environmental pollution fugitive emissions, depending on the specific content of dust fractions (kg/m3), disperse composition of dust fractions (d5, d50, d95) specific dust blowing out q mg/ (m2·s) from the volume of the rock gypsum, selected at landing sites on the open warehouse storage was investigated, which is determined by the formula [18]:
q
a vb
(3)
where q - specific dust blowing out mg/(m2·s); v - wind speed, m/s; a and b - empirical coefficients, depending on the type of overloaded material [18]. According to [19] specific dust blowing out, g/(m2·s), depending on the wind speed (m/s) and acting on the open storage of bulk materials warehouses obeys power law and also coefficients a and b were obtained to determine the dust emission from the surface for different materials. Researches of specific dust blowing out q from the rock gypsum volume, selected in place of discharge of the outdoor storage warehouse were carried out in an experimental wind tunnel, which simulates the effect of wind loading on the means of creating air artificial uniform rectilinear in the working section airflow. Wind tunnel experiments were based on the principle of reversibility of motion when movement of the air flow impinges on a fixed element. General view of the wind tunnel is shown on Fig. 1. During experimental studies suspended volume of soil (Vconv = 0,02 m3) which has a pre-measured value of the mass of sample plaster dust sifted through a sieve with a mesh size of 0,125 mm, was placed in a wind tunnel. The task of the first stage of the research was to determine a and b coefficients with exponential function q(v). In the course of this phase three types of rock mass were used: N1 – Spc = 11,75 kg/m3; N2 – Spc = 6,06 kg/m3; N3 – Spc = 2,31 kg/m3. The first type of gypsum raw material corresponds by characteristics to the mass stored in the open warehouse storage of investigated enterprise. During the research each type of raw material masses was affected by air flow at different speeds (v1 Ĭ 1 m/s; v2 Ĭ 2 m/s; v3 Ĭ 3 m/s, …, v10 Ĭ 10 m/s). During each test feedstock rate
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changed sequentially, the value of the dust mass (mg) in each experiment were summed with previous value. Thus, one error was eliminated whish affected statistical correlation of experimental results.
Fig. 1 - General view of a wind tunnel
The results, determining the specific surface blowing out from the surface of the gypsum raw materials warehouse are shown in Table 1. Table 1. Parameters defining specific blowing out from the surface of the gypsum raw materials warehouse for three types of specific content of dust fractions (kg/m3). ʋ
Name of raw materials
Characteristics of raw materials Spc, kg/m3
1
Gypsum Rock 0-50 mm Gypsum Rock 0-50 mm Gypsum Rock 0-50 mm
2 3
Parameters of the power model a
b
11,75
0,004
3,958
6,05
0,003
3,673
2,31
0,001
3,839
Calculation was made by the formulas (1) and (2) of the amount of inorganic to 20% dust emission SiO2 (gypsum dust) under static storage materials according to the characteristics previously adopted in the calculations with a and b coefficients for chalk (K4 = 1; K5 = 0,1, K6 = 0,25, Ʉ7=0,5; Fwork = 120000 m2; Fdust = 120000 m2; Ș = 0; T = 365 d.; Ɍr = 101 d.; Ɍs = 80 d.;v = 8,1 m/s): 1. Spc = 11,75 kg/m3; q = 15,77 mg/(m2·s); Ems = 23,65 g/s; Eye = 41,36 t/y. 2. Spc = 6,05 kg/m3; q = 6,51 mg/(m2·s); Ems = 9,77 g/s; Eye = 17,09 t/y. 3. Spc = 2,31 kg/m3; q = 3,07 mg/(m2·s); Ems = 4,61 g/s; Eye = 8,06 t/y. Comparison of the results of calculations with the data obtained using the coefficients a and b for chalk for any specific values of dust blowing out determined experimentally for gypsum dust are shown on Fig. 2. As can be seen on the histogram divergence values previously obtained quantity of emissions calculations (for those in [18] coefficients a and b for chalk) with the results of a regression model based on the results of the experiment is about 50%. Significant percentage differences in the results is associated with high gypsum dust fractions in the mass of rock in the open warehouse storage of gypsum raw materials, i.e. the impact of fugitive emissions of the enterprise on the environment and regulated areas initially set wryly [20]. In addition, the difference between the values of emissions while extent of the specific content of the gypsum dust in the test volume of 2,31 kg/m3 to 11,75 kg/m3 is 50-80%, indicating the need for clarification of the formula (3), however, in accordance with the results obtained in the second stage of the research, the task of which was to produce a mathematical model of the resultant index q (mg/ (m2·s)) from independent variables v (m/s) and Spc (kg /m3) of particulate analysis of dust samples weathered from mass investigated for its aerodynamic properties and their evaluation according to the speed v (m/s).
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Fig. 2. Histogram with grouped assess of calculations results of emissions from the warehouse for gypsum raw material at different values of specific dust blowing out mg / (m2 · s)
Past studies of dependence between specific dust blowing out, with the characteristics of the particulate composition of weathered dust from the wind speed and dust proportion showed that the particle diameter d5 ranges from 4 to 35 ȝm, d50 - 7 to 78 ȝm, d95 - from 12 to 92 ȝm. The values of the characteristics of integral distribution functions of the mass particle over diameters, namely d5, d50, d95 of dust weathered from the test mass of the gypsum raw material at various air speeds are shown on Fig. 3.
Fig. 3. Integral function mass distribution of dust particle over diameters in logarithmic likelihood-grid for dust samples from the weathered studied weight gypsum raw material at different air speeds v (m/s):1) 1,2 - 1,6 m/s; 2) 2,2 - 2,4 m/s; 3) 4,1 - 4,9 m/s; 4) 5,3 - 5,9 m/s; 5) 7,0 - 7,9 m/s; 6) 8,4 - 8,6 m/s; 7) 9,1 - 9,6 m/s; 8) 10,3 - 10,5 m/s; 9) 11,2 - 11,7 m/s; 10) 12,0 - 12,3 m/s
Construction of the base regression models was performed in an integrated system analysis and data management - STATISTICA Advanced Linear/Nonlinear Models (recessed linear/non-linear model) [21, 22, 23]. As a form of a mathematical model exponential growth ( y c exp b0 b1 x1 b2 x2 ) was taken as ratio between the studied variables at the beginning of the research which is very different from the ratio in the final levels of independent variables, that is, in the preformed pattern (figure experimental studies values) of the point with maximum curvature and smoothness leave up, which is clearly faster than the linear and power function. As the error
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function method of least squares is used. The method of assessing the adequacy of the mathematical model quasiNewton method was selected. Shows received adequate mathematical model specific dust blowing out, q, mg/(m2·s):
q v, Sɪɫ
4,93752 exp 0, 068983 0, 233714v 0,112124Sɪɫ ;
(4)
Figure 4 shows the response surface constructed from the dust blowing out resulting mathematical model. Diagram shows that a sharp increase in the weathering values (dust gypsum blowing out) occurs with increasing air flow rate of more than 6 m/s and an increase in levels of dust fractions of more than 7 kg/m3, while the level of dust content of less than 7 kg/m3 change in the surface values response has a smooth character.
Fig. 4. Figure specific surface response dust blowing out, q depending on the levels of specific combinations of gypsum dust content in the test volume Spc and air flow rate v
According to [24] researches of sedimentation rate of the particles contained in the plaster dust obtained sample weights (10 composite samples) during the research of dependence of the specific dust blowing out from the air flow rate and the specific content of dust fractions in the rock mass were conducted. The studies established, intervals settling dust fractions, obtained values of sedimentation velocity (Table 2). The results of the gypsum particles settling studies were constructed based on the equivalent settling velocity of the particle diameter in logarithmic grid (Fig. 5).
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The resulting dependence of the rate of subsidence of the equivalent diameter of the particles, allow us to offer a formula for determining the rate of sedimentation of dust particles contained in the rock mass in the open warehouse storage of raw materials.
vs
A e Bd ;
(5)
or ln vs
ln A Bd ;
(6)
where vs - dust particle settling velocity, m/s; d - equivalent diameter of the particles of dust; A, B - factors that characterize the type of dust. Table 2. Characterization of dust fractions obtained in the study of specific dust blowing out. Gap subsidence, s
Features of the particulate composition, ȝm
Sedimentation speed, m/s
d5
bottom line
d50
d95
upper bound
1-2
35
78
92
1,2
2,5
2-3
30
71
91
0,6
1,2
3-4
29
60
81
0,4
0,6
4-5
24
51
70
0,3
0,4
5-6
19
41
60
0,24
0,3
6-30
16
36
50
0,2
0,24
30-60
9
20
26
0,04
0,2
60-120
6
16
21
0,02
0,04
120-300
5
10
13
0,01
0,02
Ȼɨɥɟɟ 300
4
7
12
-
0,01
Fig.5. The dependence of the sedimentation rate of the equivalent diameter of the particles in the logarithmic grid: d5 - minimum equivalent diameter; d50 - median equivalent diameter; d95 - maximum equivalent diameters.
2. Conclusion The specific content of dust fractions Spc (kg/m3) was determined based on the weight fraction of plaster dust able to extend beyond the boundaries of open gypsum storage warehouse 0-105 ȝm (maximum particle diameter of the fixed boundaries of the warehouse).
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Handled studies of sedimentation rate depending on the equivalent diameter of the dust particles, led to the conclusion that when sedimentation rate 1,2 - 2,5 m/s particles have maximum size of 92 ȝm, median size of 78 ȝm and minimum size 35 ȝm. When settling rate of less than 0,01 m/s particles have a maximum size of 12 ȝm, median size of 7 ȝm and minimum size of 4 ȝm. According to the results of analytical and experimental studies of the mathematical model (regression equation) for determination of the specific plaster dust blowing out stored in the open air, depending on the air flow rate and the content of dust in the rock mass. Studies have shown that the fine dust content exceeds established on the border of regulated areas for inorganic dust up to 20% SiO2 (plaster dust) (5,9 to 16,0 shares of MAC), which leads to the deterioration of sanitary conditions in the plant, on the borders of the sanitary protection zone (SPZ) for regulated areas, and also leads to loss of gypsum raw materials. References [1] A.V. Azarov, A.B. Strelyaeva, N.A. Marinin, The significance of the particulate composition of dust in technological processes, Internet Journal of VolgGASU. 28 (2013). [2] V.N. Azarov, N.A. Marinin, R.A. Burkhanova, A.V. Azarov, About composition of the dust dispersed in the air during materialproduction, Bulletin of Volgograd State University of Architecture and Civil Engineering, Series: Construction and architecture. 30 (2013) 256260. [3] V.N. Azarov, N.A. Marinin, N.S. Barikaeva, T.N. Lopatina, About air pollution by fine-dispersed dust in urban areas, Biosphere compatibility: people, region, technology. 1 (2013) 3034. [4] A.B. Strelyaeva, N.S. Barikaeva, E.A. Kalyuzhina, D.A. Nikolenko, Analysis of air pollution sources by fine-dispersed dust, Internet Journal VolgGASU. 34 (2014). [5] V.N. Azarov, I.V. Tertishnikov, E.A. Kalyuzhina, N.A. Marinin, An estimate of the concentration of fine-dispersed dust (ɊɆ10 ɢ ɊɆ2,5) in the air, Bulletin of Volgograd State University of Architecture and Civil Engineering, Series: Construction and architecture. 25 (2011) 402 406. [6] N.S. Barikaeva, A.B. Strelyaeva, R.V. Orlov, Estimation of suspended particles PM10 and PM2,5 in the air of residential areas, International Journal of Alternative Energy and Ecology. 134 (2013) 3941. [7] V.N. Azarov, A.V. Azarov, RU Certificate of the state registration of computer program 2014618468. (2014). [8] V.N. Azarov, E.Y. Esin, N.V. Azarov, The analysis of the dust composition dispersed in the technosphere, Tutorial, Federal Agency for Education of Russian Federation, Volgograd State University of Architecture and Civil Engineering,Volgograd, 2008. [9] V.N. Azarov, N.M. Sergina, Methods of microscopic analysis of particulate dust composition using PC, deposited the manuscript 1332V2002, 2002. [10] V.N. Azarov, Improving dusty environment assessment and implement measures to reduce dusty air at working and sanitary protection zones of industrial enterprises, Dr. diss., Rostov-on-Don, 2003. [11] V.N. Azarov, V.Yu. Yurkyan, N.M. Sergina, A.V. Kovalev, Methods of microscopic analysis of disperse composition of dust using a personal computer (PC), Legislative and applied metrology. 1 (2004) 4648. [12] V.N. Azarov, N.A. Marinin, D.A. Zhogoleva, On an estimate of the concentration of fine dust (PM10 and PM2,5) in the atmosphere of cities, Proceedings of South-Western State University. 38 (2011) 144149. [13] Technique of microscopic analysis of disperse dust composition using a personal computer (PC), The list of methods of measurements of concentrations of pollutants in the emissions of the industrial enterprises, approved for use in 2014, SRI Atmosphere, St. Petersburg, 2013. [14] Particle image processing program DUST 1: the testimony of the state. reg. computer software DUST 1, 2014. [15] V.N. Azarov, S.A. Koshkarev, M.A. Nikolenko, Systems abatement dedusting using particulate dust analysis in the construction industry, Engineering Don bulletin. 34 (2015). [16] N.S. Ponomareva, About chalk dust concentration in the air of working zones and emissions into the atmosphere at the enterprises construction industry, Bulletin of Volgograd State University of Architecture and Civil Engineering, Series: Construction and architecture. 20 (2010) 9398. [17] V.N. Azarov O.V. Yurkyan, N.M. Sergina, Methods of microscopic analysis of disperse dust composition using a personal computer (PC), Legal and applied metrology. 1 (2004) 4648. [18] Guidelines for calculation of emissions from fugitive sources in the building materials industry, NIPIOTSTROM, Novorossiysk, 2001. [19] A.I. Loboda, V.Y. Tyschuk, Influence of waste dumps on the dustiness of the atmosphere and ways of its normalization, Safety in the mining industry: industry. thematic collection, Minchermeta. (1986) 4751. [20] T.V. Doncova, S.S. Hrapov, V.N. Azarov, About modeling of transport pollutant dynamics in the atmosphere of cities, International Journal of Alternative Energy and Ecology. 134 (2013) 6772. [21] V.N. Azarov, V.I. Boglaev, N.A. Marinin, Description of disperse composition of dust aspiration systems in the manufacture of gypsum, in: Proceeding of IX International Conference indoor air quality and the environment, VolgGASU, Volgograd. (2011) 8690. [22] H.J. Seltman, Experimental Design and Analysis, 2015. [23] R.O. Kuehl, Design of Experiments: Statistical Principles of Research Design and Analysis, 2nd Edition. [24] S.A. Koshkarev, US Patent 156520. (2015).