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���H��6D.#�" 9��/ Specifically, we use Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) to reveal the microstructure of coal from two aspects of functional group and carbon skeleton structure and obtain the micro information of the surface functional group types, quantity, and carbon structure of coal with different degrees of metamorphism, as well as the change rule of functional group of coal sample with coal rank and the law of carbon increase and deoxidization of coal metamorphism.

Different dusts will have different combustion temperatures and dust of various types will either suppress or elevate this temperature in relation to the stoichiometric concentration of the dusts. 190 11 Mining of coal leads to coal dust and flour mills likewise have large amounts of flour dust as a result of milling. Dust filling a volume of 10 litres is sufficient to produce an explosion. Finally, this paper constructs an evaluation model for the influencing factors of coal dust wettability, explains the influence degree of different coal dust structure on coal dust wettability, improves the coal dust wettability mechanism, and provides more quantitative research ideas and methods for the control of coal dust. The full text of this article hosted at iucr.org is unavailable due to technical difficulties. Coal dust explosion tests were performed in a 20-L spherical vessel and the post-explosion dust samples were collected for analysis. @MB��k`z�i،� Ж� ����@��Z

Generally, dust suppressants are commonly applied in coal mines.

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Many materials which are commonly known to combust can generate a dust explosion, such as coal, sawdust, and magnesium. There are five necessary conditions for a dust explosion: If any of these five conditions is missing there can be no dust explosion.

��k�#�4 �'D���l����:������7�����| Fr1��?�N'�.�Y�r�@f�y�T����}���r�x��'�����1soZ�]V�lb�e�n.-5��-a�a���]�Z��C%��_�V�QE�G�n�o*�������Þ�����h���A�����V�)V݅�6��A��-$3���oNo�R [2] Common sources of ignition include: Below a certain value, the lower explosive limit (LEL),[2] there is simply insufficient dust to support the combustion at the rate required for an explosion.

To develop a better dust suppressant, we attempt to explore the factors affecting the wettability of coal dust under different metamorphic levels from the essence of coal dust wetting mechanism in this paper. 200 0 obj<>stream %PDF-1.6 %����

startxref Mines may also be sprayed with water to inhibit ignition.

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It is necessary that sufficient energy, generally either thermal or electrical, be applied to trigger combustion. College of Chemical Engineering and Safety, Binzhou University, Binzhou, China, Donadeo Innovation Centre for Engineering, University of Alberta, Edmonton, Alberta, Canada.

%%EOF These mines must develop, establish and maintain an adequate and effective safety and health management system (SHMS) to ensure risk from such hazards is at an acceptable level.

0000002343 00000 n A dust explosion refers to the explosive combustion of a dust suspended in air in an enclosed location. A coal dust explosion is one of the principal hazards in an underground coal mine.

endstream endobj 196 0 obj<> endobj 197 0 obj<> endobj 198 0 obj<>stream What is more, coal dust explosion seriously affects coal mine safety production and coal miners' life safety.

0000001599 00000 n Use the link below to share a full-text version of this article with your friends and colleagues. trailer However, many otherwise mundane materials can also lead to a dangerous dust cloud such as grain, flour, sugar, powdered milk and pollen. Different dusts will have different combustion temperatures and dust of various types will either suppress or elevate this temperature in relation to the stoichiometric concentration of the dusts. ���&��|���)(L�>�])�);�4�Q����r����.�7�n��&�.

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GQ�j�ۿ��"��V�Ar1SuP��h*Ʉ�Gࣟz�c����(6ًJ�8ùj_��z��^�A�����|�t5����ә��;W�&�$;��ߦ��v����Z�Wo�5��P�YƂ�(��\�K�%-=F���쭆��B��9¤��6b����.�坹�9�3Խ�=9�������F;h.��O��e�`��"*k��z���* �T#-K�+�XF>u�)m�T#�1f���{�� Z�)v 9�+�r��H>@(�rz�hއ��Ek$��B3A�9 +��v�՛ ��Iv6|Aεml���J�Y�$�{)�4���Ⱦ1y^��"X�;n�XU�GL��#��u���~qƖ��0(o �S��O���U�Bn}����gW�7:K�zJi�[kF�>��l?^H^�YD�mY��c��&|��hh0���57*P����^�$���C�Zq�#��:���ׯ;���@�;A���|5���㙭����/'��#��6���0���d��p�������t�f�~�b�?���4���v�BK>֟���9�H�x3 tT�s�BEᣨ�I��^�rn�G���n�T�2j��U/��.�@�B�GN�Mm���S� Х����<8ەM�zA��u��L\�㠯o��S��_N��h�/�'�bIt��JD�!����CU�4�T�)��$Vm[�?Y���^dӡSM�I�|�X�s����H�Jм��T[���ގ��S��駩+���MZW�8V Thermobaric weapons, depending upon their fuel, are also a potential and intentional source of dust. It is necessary that sufficient energy, generally either thermal or electrical, be applied to trigger combustion. Experimental equipment An XKWB-1 sealed explosion system was used. In the coal mining industry, rock dust (usually limestone) is added to the coal dust deposits to act as a heat sink and inhibit flame propagation. xref After that, we acquired the structural parameters of coal by the NMR experiments and fitted the quantitative mathematical relationship between the microstructure parameters and wettability of coal through SPSS and ORIGIN software. These data and research results could be useful for better understanding the mechanism of methane–air–coal dust mixtures.

Mechanism of dust explosions . x�b```a`` Similarly, if the fuel/air ratio increases above the upper explosive limit there is insufficient oxidant to permit combustion to continue at the necessary rate.

0000001505 00000 n The energy produced is liberated gradually and harmlessly because it is dissipated as quickly as it is released. Experimental 2.1. A coal dust explosion in a mine entry can be initiated by a methane-air explosion that generates sufficient air pressure to disperse coal dust from the entry surfaces into the expanding combustion zone.

However, current dust suppressants are not working effectively. In the coal mining industry, stone dust is spread along mine roadways, or suspended from trays in the roof, so as to dilute the coal dust raised ahead of the combustion zone by the shock wave, to the point where it cannot burn.

Respirable coal dust accounts for heart and respiratory diseases of coal miners such as asthma, pneumoconiosis, and black lung disease.

Due to the thermal expansion of the gas, the pressure increases. Working off-campus? 190 0 obj <> endobj Learn more. Due to the small volume in relation to the large surface area, combustion can then proceed very rapidly and the flame front can also travel quickly.

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Dust is defined as Powder (substance)s with particles less than about 500 micrometres in diameter, but finer dust will present a much greater hazard than coarse particles by virtue of the larger surface area. Please check your email for instructions on resetting your password.

If you do not receive an email within 10 minutes, your email address may not be registered, Learn about our remote access options, College of Safety and Environmental Engineering, Shandong University of Science and Technology, Qingdao, China, State Key Laboratory of Mining Disaster Prevention and Control Co‐founded by Shandong Province and the Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao, China.

The alternatives for making processes and plants safer depend on the industry. Characteristics of Dust Explosions When a mass of solid flammable material is heated it burns away slowly owing to the limited surface area exposed to the oxygen of the air. A similar problem occurs in saw mills and other places dedicated to carpentry.

Enter your email address below and we will send you your username, If the address matches an existing account you will receive an email with instructions to retrieve your username, By continuing to browse this site, you agree to its use of cookies as described in our, I have read and accept the Wiley Online Library Terms and Conditions of Use. Reaction mechanism Dust/air mixture heterogeneous; reaction may be heterogeneous (few) or homogenous (most) Most dusts explode as gas explosions Volatiles from solid material Explosion: FUEL (dust) and OXIDANT are MIXED, ignited by IGNITION SOURCE, and sufficient CONFINEMENT results in overpressure development 25 Dust Explosion Fundamentals. The dust can arise from activities such as transporting grain and indeed grain silos do regularly have explosions. In an enclosed space this leads to the condition called overpressure.

Much research has been carried out in Europe and elsewhere to understand how to control these dangers, but explosions still occur.

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H�dSKo�0��W��Ɗ��DZm\,�����h��Μ���dIV�� ?~�w��q��3d����̭170� �_�A���Rq(5s��j�7�]�#�� @�\x�k���u*� SHL�����O#X�� �L��>����'��0)p|����cP��Y�vկ^ڴY�M#�M1���0��ݶ�Y���υ&�@P^ �Y DA�]40vj�L��24�=��ҿ�Dy�?��Å ��)�&�=����!�s��������3*�H(i2]w�T:E"���o���2 եL�ԙ�E�)���I��8`��?F�8} P� X�]5;�5��H�iݭ�����K� �M̪o�+���nj*'Z�td�� ��C6'�R➅N���*����I�$c�t�j����U��U(���q�֪Qr�~O4�����o9���S�O� t� 0000000516 00000 n The dust must also consist of very small particles, where the surface area is very large, and so will support combustion. and you may need to create a new Wiley Online Library account. Heat transfer to the coal dust particles results in the production of volatiles and tars from these particles. <]>>

0 For stories about incidents in France and the USA see, List of neighborhoods of the District of Columbia by ward, Writ of Amparo and Habeas Data (Philippines), http://www.hse.gov.uk/foi/internalops/hid/din/529.pdf, http://www.se-safety.com/ppt/prevdustex/prevdustex.ppt, https://publicsafety.wikia.org/wiki/Dust_explosion?oldid=8012, The dust is suspended in the air at a sufficient. c`f`�gd@ A�;s400�L�Th`h�i``8��]�g�Þ�y>��H��ݣr-X�͙�u�SDؾ7�e��P�`�b�>�ӣ�t�иF��)�J&��)Z;/�6IU�8��,�T��)ˁ��l�uf��t�o�ȹ8�Զ����������"��s�S�D9���d-��n�gf[�J��Y�sq�7�ȭyOo_���� rz ���``�h`b6 ��`c`��``�;��@�J@���!�D�5�3��ri NZ0�D�0��� ��f��t�l��I ! �� �+������疏X�7KO͕�m^q���{��Z��8���f�q�9�\.�#[\;����+�uD��M� �� 2. 0000074294 00000 n

Respirable coal dust accounts for heart and respiratory diseases of coal miners such as asthma, pneumoconiosis, and black lung disease. 0000002164 00000 n A figure 20% lower than the LEL is considered safe.

Many powdered metals, like aluminium, can form explosive suspensions in air.

0000001134 00000 n