Cement, Energy and Environment July-Sep 2002

worthy neighbour to the shining the 'feed' conveyor, which passively The more complex and energy new Kuala Lumpur. controls the flow of dust-laden air. involved in the material transfer, the Courtesy: IV orldCement, Jul 02, Pp. 77-81, Enquily no. 2 Fax: +././(0) 1252 718992 Email: mai/(iijworldcement.c.:um IVeb: ll'lt'lt'.worldcement. com CENTRE TO TIGHTEN EMISSION NORMS S/whhajit Roy, The T OJ, 27Jun. 2002. The Union Ministry for Road Transport and Highways has okayed the En v ironment Ministry's proposal to raise the standards for As compared to conventional bag– house or suppression systems, the passive system controls fugi t ive dust in transfer operations to at least equal and soHJt::limes gre·ater levels. The primary dust generating mechanism in the transfer of bulk materials is from air induced to flow with fal ling or projected material. The bulk material creates a frictional drag on the ai r around it and induces air to flow in its wake. When the falling or projected material comes to rest (on the conveyor or other equipment below), the induced air greater the engineering and design changes required to properl y control material and dust-laden airflow. The technology can be successfu lly applied as a partial Dustless Transfer®when physical constraints do not allow installation of a fu ll recircu lation chamber. The technology can also be utiIized to supplement or reduce collection air requi rements for act ive dust collection system s, wh en the Dustless TransferOll alone is not sufficient for dust control. The Dustless Transfer'~) is a checking vehicular emission. The pressuri zes the materia l handli ng proven, alternate technology for new norms are likely to be notified enclosure and flows out the end of control ling fugit ive du st 111 soon. Thi s move comes close on the hee ls of th e De lhi State Government's drive to scruti nizc PUC (pol lution under con tro l) certificates. scheduled to begin from I Jul y. The Road Transport the chute or other leaks under the ski1t of tail seal. The escaping air entrains free particulates becomi ng dustlad en. A second du s t generat ing mechanism occurs when dust-laden a ir is mec hani cal ly Mini stry would now amend the pushed from under ski1ting by the C 'entra/ Molor Vehicle Act 's Rule flexing oft he conveyor belt between 11 5 and in c lude testing of support poi nts (idlers) as a result of hydrocarbons. At present, poll ution material impact. checking centres record only carbon The Dus tl ess Tra ns fer ll<l monoxide leve ls. The proposed rei ieve s pres sure gene rated by ca rbon monoxide levels are also induced ai rflow in the load zone of going to be much higher than the current standards. the belt conveyor by providing a low-resistance recirculation path. The air is recircu lated from the load conveyor-to-conveyor transfers. It is an effective tool in the available arsenal of dust contro l measures, when ~signed and app lied properly. The passive system relics on des ign of a low-r es is tance rec ircu lation pathway to all ow internal recirculation of the induced .airfl ow. The most difficu lt part of the design is calculating the required induced airflow and adequate des ign ing to accommodate thi s ai rll ow. Maintenance of seali ng com ponent s is important to maintain long-term, trouble- free dust control. ( 'oune.1y: Teri Newswire. 16-JOJune 2002. P21. Fax: 9I II .J682/./.J !-:-mail: outrench'a )teri.res.in ll'eh: 11' 11'11'. teriin.urg zo ne ba ck to the source (head The Dustless Transfer "' is best pulley). which results in internal suited fo r conveyor-to- conveyor recirculation of air instead or a net transfers wit h reasonable fall outllow or air from the enclosure. heights and enclosures tha t can be If no air escapes the enclosure, then tightl y sealed. Partial installations DUSTLESS TRANSFER·· OF BULK SOLIDS Darren II. Wood. USA Dus tle ss T rans fe r® is a s trai ght-forward technology for cont roll ing l'ugitive dust emi ss ions from bulk so lid s handling ope rati ons. It recircu lates the induced airflow from the ·take no dust escapes the enclosure either. The inc reasing conccnterati on of du st pa rti c les in sid e th e reci rculation chamber and properly engineered air ve loc itie s cause agglomeration f rom partie lc co lli s ion and sett ling. T he agglomerated dust fal ls back on to the loaded conveyor and sellles into away' conveyor back to the head of the voids. of the technology have resulted in redu ction in a irborne dust from unacceptably high level s to less than 25% of the respirable dust limit. Courtesy: Bttlk solids handling. I 'o/. 22. :\lay-Jun. 1002. Pp211-213. Fnx: ./95323 96 97 % E mni/' llp(ij}tmll.l'tech-online.cnm l l"ch: ll'll'll'.tr nnstech-lll tl itte. co111 .- .... .