Cement Energy and Environment

J down the gas temperature, these require no water. As a result, there is a saving of I 000 m 3 water per day. Training and Continuing Education Plant engineers are imparted regular training on pollution control in all its aspects. Apart from this, they are periodically deputed for training programmes held by institutions like NJTlE, NCB and RTC. Likewise. workers also undergo periodical in- house training on issues related to environment. A view ofthe cement mill "0" sepa baghouse to which 2 modules have been added Returns From Emironmental Modification - A Case Stud~ Consequent upon the upgrading of cement mill II from a rated output of 150 TPH to 170 TPH through va rious modifications inside the mill and in the mill circuit. the increased gas tlow upset the operating parameters of 0- Sepa separator bag house leading to an increase in the baghouse differen tial pressure to 320 - 340 mm WG. This, in turn, caused the filtering capacity to drop and a high stack emission level 45 mg/Nm 1 from 30 mg/Nm 3 , besides. of course. a higher power consumption . A solution to this problem was sought through increase in the filtering area i.e. reduction in the air-to-cloth ratio. Concomitant with this, two additiona l modul es/zones were provided down stream the ex isting bag house (see photo ). This chain of modifications produced the de:-ired resu lt, namely, reduction in differential pressure, i.e . increase in process flows, i.e. increase in production and ultimately reduction in stack emiss ion level 28 mg/Nm 1 and in power consumpt ion by 0.7 un it/ton of cement produced. Table l gives a comparati ve accourll of the operational parameters before and after the modification. Table 1 Comparative operational parameters before and after modification Parameter Before After modification modification No of bags 2304 2560 (Type 18Z128) (Type 20Z128) Air-to-cloth ratio m 3 /min/m 2 1.38 1.24 Bag house 320-340 220-270 differential pressure, mm WG Bag-house fan PowerkW 625 525 Power 3.7 3.0 consumed, units/tonne Bag-life, years 2 2.5 Emission level mg/Nm 3 45 28 El·onomics The vital economics of the modification are as under: Investment on extension of bag-house Rs. 4.3 lac Saving in terms of' lower power consumption and enhanced in bag life Rs.l.75 lac/month Payback period 90 days AnnuaJ saving due to modification Rs. 2llac 3