part 1: overview of cogeneration and its status in asia - Fire

Sample case study in a pulp and paper mill 103
CHAPTER 2: SAMPLE CASE STUDY IN A PULP AND PAPER MILL
2.1 Project Description
The Container Corporation of the Philippines (CCP) which uses electricity and thermal
energy simultaneously, plans to set up a cogeneration plant. Located at Balintawak, Quezon
City, it is a paperboard mill and converting plant. It produces various paperboards by
recycling waste papers. CCP operates its mill 365 days a year with 24 hours a day in three
shifts. The mill operation is stopped only due to breakdown of machines, scheduled
maintenance of equipment, power interruption and calamities such as typhoons, fires, etc.
This mill offers a good opportunity for cogeneration as it has steady thermal and electrical
loads, and it requires a steady supply of energy in order to avoid production losses. Before
deciding on making a substantial investment in this project, it is necessary to carry out a
thorough financial analysis of the possible cogeneration alternatives.
The method of conducting pre-feasibility of cogeneration in CCP involves a three-step
procedure, i.e., search and identification of alternatives, estimation of costs and savings, and
economic evaluation of all options.
2.2 Identification of Possible Cogeneration System Alternatives
This stage involves (1) analysis of the current energy consumption pattern of the CCP plant,
and (2) identification of possible cogeneration candidates, and evaluation of technical
parameters for each candidate.
2.2.1 Current Energy Consumption
a) Power consumption
Electricity in the paper factory is used for board making (47 per cent), papermaking (51 per
cent) and lighting & air-conditioning (2 per cent). Analysis of the monthly electricity
consumption of the factory in 1996 shows the following:
• Maximum Monthly Electricity Consumption (May): 1,377 MWh
• Minimum Monthly Electricity Consumption (March): 740 MWh
• Peak Power Demand: 2,430 kW
• Base Power Demand: 2,040 KW
• Total Electricity Consumption in 1991: 12,715 MWh
b) Steam consumption
CCP uses 98 per cent of the total steam production for paper drying while 2 per cent is used
for cleaning the process equipment. Paper drying at CCP requires saturated steam at a
pressure of 7 bar. The steam requirement is met by two boilers with capacities of 9 tons/hr
and 13 tons/hr respectively. Bunker oil is used as fuel for boilers.
Detailed steam and fuel consumption data were analyzed to derive monthly consumption in
1996, daily consumption pattern during the month with high demand, hourly steam demand
profile of the factory for sample peak days. The analysis led to the following: