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

164 Part3: Summary of country studies – Bangladesh and Viet Nam
4.2 Technical Potential for Cogeneration
4.2.1 Identification of sub-sectors with cogeneration potential
Since the textile industry has quite a steady need for various types of energy for its process,
including thermal, refrigeration, and electricity, it is suitable for cogeneration applications.
Unfortunately, no textile factory has so far adopted cogeneration although some of them have
diesel power generation units of large capacities.
The chemical industry, particularly rubber, consumes a lot of electric and thermal energy. In
Viet Nam, most of rubber factories are very old with outdated energy equipment. As it is time
for their process equipment to be replaced, this provides a good opportunity for adopting
cogeneration.
Hotels and office buildings in the commercial sector are big energy consumers. There has
been considerable investment received from foreign companies for their development. These
buildings use electricity to operate cooling systems. They are often poorly designed from
energy aspects since investors have the habit of copying the designs from abroad without
giving due consideration to the local climatic conditions.
Some foreign direct investment companies in the food-processing sector such as Foremost
milk processing factory, Walls ice cream factory, meet their power demand by selfgeneration.
They can easily upgrade their existing energy generation system to operate in
cogeneration mode.
4.2.2 Existing cogeneration facilities in the country
There are several industrial factories in Viet Nam which already have cogeneration facilities
such as the Bai Bang paper factory in northern region, and sugar mills. The Cogido paper
mill, in Southern region, used to have a cogeneration capacity of 9,000 kVA. Installed since
the first commissioning of the mill in 1959, this unit can no longer be used now. Therefore,
the cogeneration technology seems to be familiar to the paper & pulp and sugar sub-sectors
in Viet Nam.
A study sponsored by EC-ASEAN Programme has estimated the total potential of power
generation from sugar mills in Viet Nam to be 250 MW. However, in reality only a few mills
can sell their excess electricity to the utility grid and several others are going through the
negotiation phase. Most of the factories have big difficulty in handling the excess bagasse.
Industries where cogeneration has been in use are pulp and paper, sugar and nitrogen
fertilizer. A paper mill in the north is equipped with fluidized circulating bed boiler of a capacity
to generate 145 tons of steam per hour at 73 bar and 450°C. The plant also has a recovery
boiler fired by the waste from the process, producing 36 tons of steam per hour at the same
temperature and pressure. The steam from the boilers is passed through 2 turbines: one is a
back-pressure turbine producing 12 MW of electricity and the steam leaves at 3 bar for
processes, and the other is a condensing turbine designed to generate 16 MW of electricity.
Though the mill is quite large in size and is equipped with relatively modern technology, the
performance of the cogeneration plant has deteriorated substantially after 20 years of
operation and poor maintenance.
Another paper mill in the Southern region, Dong Nai province, has an oil-fired boiler with a
capacity to produce 40 tons of steam per hour. The cogeneration facility includes an
extraction-condensing turbine of 5 MW capacity. However, the unit is not used since the mill
can get electricity from grid easily. With some modification, the existing unit can be easily
modified to operate as a cogeneration facility in this mill.