Cement Energy and Environment

• 2.2 Basis for Proposed System Design Initially detailed study is carried out in-house to know whether coal tar can be used as AFR in cement kiln. Contacted Morbi ceramic industry association members to know the availability of material, mode of collection and transportation. Samples were collected & tested from different Coal Tar generating units in Morbi Industrial area. Based on the study coal tar firing system has been installed and extensive trial taken in presence of GPCB and CPCB officials as per regulatory norms and who in turn granted an authorization for co-processing of 54048 MT/annum Coal Tar. 2.3 Brief of coal tar firing system Coal tar is received in closed tanl<er, similar to one which is used in transporting HSD or petrol. Figure-2: Tanker for Coal Tar Transportation Coal Tar from tanker is unloaded in storage tank of 20 KL capacity using adequate capacity pumps. Figure-3: Coal Tar Storage Tank- 20 KL Ca acity Coal Tar tank have heating elements to make the Coal Tar flowable through pipe lines. The tank is having high and low level limit switches and temperature control system. Coal tar from tank is pumped to day tank of 5KL capacity which is nearer to the preheater calciners. The conveying pipe line is heat traced with elements having thermostat based cutoff facility. From Day tank the Coal Tar is pumped to calciner and fired through burner in controlled dosage. The entire coal tar firing system is operated and controlled through ECS from Central Control Room. 3.0 Step by step changes made to improve the Coal Tar firing system. 3.1 Pumping system: Initially screw pump was used to unload Coal Tar tanker and pumping of coal to firing point. Because of high viscosity of Coal Tar and higher temperature the pumps often failed, they are replaced with geared pump having mechanical seal. Mechanical seal eliminated the issue of gland failure due to high temperature. 3.2 Conveying line: Initially conveying lines were without heat tracers, leading to problem of line jamming. Provided return line and heat tracers for recirculation of Coal Tar till required temperature is achieved and proper flowability is ensured. 3.3 Level sensors in storage tanks: Initially experienced problem of manual loading and unloading of Coal Tar from tanker as well as tank. Installation of level sensor with controlled heating for desired temperature having operational interlock for pump operation stabilized for the entire firing cycle. 3.4 Automation Advanced instrumentation control for flow regulation and operation through PLC based logic from CCR helped to gradually increase consumption rate without any adverse effect on pyre– processing system as well as product quality. 12