Ntpcrihandnagar.blogspot.com Website Review

coal properties constantly vary due to sizing differences and the adverse impact of moisture. these affect heating value, flow characteristics and density.the resultant density changes are measured by the gravimetric feeder.  the gravimetric feeder compensates for the variation in bulk density and feeds a fixed weight of coal in response to a boiler fuel demand this ability to accurately weigh the coal provides significant improvement over volumetric types in terms of matching the fuel delivered by the feeder to the actual process energy required on coal fired units. benefits of gravimetric feeder performancereduced safety concernshow it works : gravimetric mode gravimetric feeder w… controlled fast cooling procedure normally rihand-ii and iii 500 mw units take 8-9 days to stop barringusing cfcp, it takes roughy 75 hours after desynchronisation.it is done in 2 stages.first stage: unit parameters lowered by reducing load and steam parameters.second stage: after desynchronisation, till 350 deg( hp casing temp), it is to be cooled thru natural cooling. expansions, axial shift, bearing temperatures, bearing & shaft vibrations need to be observed and logged in the sheet and if any deviation found, should be rectified.and if these deviations are beyond rectification, then abort force cooling.stage i : parameters ensure all auto loops and slcs in service and ms temp <480 deg to be bypas*ed in order to lower temperature. (desk, control desk, sce  & ensure boiler stop valves (ms01 & ms02 ) and its ibv ( ms03 , ms04 , ms05 & ms06 ) are in closed condition.ensure all drains to uft are opened & all drains to sdft are closedensure complete de-pressurization of main steam lineensure tdbfp common aux steam supply mov or manual valve (at aux prds floor ) is in closed condition).ensure maw15aa001 (seal steam supply bypas* mov) is in closed conditionclose maw10aa011 (seal steam header drain going to hpft) & open its atmospheric drainstop both vacuum pump & its