PROCESS DESCRIPTION
1. INTRODUCTION
The clinker grinding facility will be sized to produce 100 MTPH cement in one cement mill system. Low initial and operating costs are targeted to ensure a viable project.
In its conceptual approach to the development of a process and the design of the cement production facility, Hanjung targets a well-functioning, easy-to-operate and low capital process plant. Heavy emphasis is placed on simplicity of process and plant design, and on adaptability to local conditions.
2. PLANT DESCRIPTION
The equipment sizes indicated feature the latest technology and system design. Highlights of each system are as summarized below.
2.1 Clinker and Gypsum Storage and Handling
The clinker and gypsum transported by river vessels from Chittagong or Mongla will be unloaded by means of a grab crane installed at jetty.
The jetty is located approximately 60m away from the river bank.
The average capacity of grab crane is 150 t/h.
Unloaded clinker or gypsum is conveyed to either the clinker storage with a capacity of 40,000 MT or the gypsum storage with a capacity of 5,000 MT.
Conveyed gypsum is stacked by a reversible belt conveyor to reduce the size of storage
2.2 Clinker and Gypsum Transport to Feed Bins
The clinker is extracted from the clinker storage by gravity type gates and belt conveyor(s). And stored gypsum is reclaimed by a front-end loader.
Reclaimed clinker or gypsum is then alternatively transported via a belt conveyor line and a bucket elevator to respective feed bins.
2.3 Cement Grinding System
The cement grinding area consists of a 4.2m dia. X 13.7m length ball mill with a 3500 kw central drive motor in closed circuit with an O-Sepa N-2500 high efficiency separator. The system is capable of producing 100 MTPH of Ordinary Portland Cement at 3000 Blaine.
The mill discharge material is conveyed by airslide and bucket elevator to the O-Sepa where the coarse material rejects are removed for further grinding.
Cooling in the mill to avoid gypsum dehydration is accomplished by water injection. The water injection system is controlled automatically as a function of the mill exit material temperature.
The O-sepa. classification air consists of primary air and secondary bleed air. The primary air is the recirculated hot air of separator exhaust prededusted by cyclones. The secondary air consists of bleed air and auxiliary vent air from the bucket elevator and airslides.
A constant exit air volume from the O-sepa. should be maintained and controlled by adjusting the bleed air damper and separator fan damper.
A recirculating air duct is installed to increase the heat in the system. The recirculating hot air is taken after the separator fan, while the remaining air is vented through a bag filter.
The mill is vented via a grit separator through a bag filter. The dust collected by mill vent grit separator and bag filter will be recycled by joining to the recirculation bucket elevator.
2.4 Cement Transport to Cement Silo
The product from the cement grinding system is conveyed by airslides and a bucket elevator to the cement silo.
The silo will be designed by Haver & Boecker.