INTRODUCTION
: Boiler is the most commonly found energy equipment
in the industry. Performance of the boiler
system not only affects the fuel consumption directly,
but also, at times controls the production output and
quality of product. The Steam system comprises of following components : |
| Steam generation |
: |
Boiler |
| Steam Distribution system |
: |
Pressure reducing stations,
steam traps, steam piping and
insulation. |
| Steam
Utilization system |
: |
End use equipment that consumes steam. |
|
Normally the energy conservation activity in steam system starts from steam
generation and concludes with steam distribution. It has been our observation
that the maximum energy saving potential is in the steam utilization system.
This may sound little absurd, but is definitely logical. The Case study series
is carefully designed to identify and evaluate the impact of Energy conservation activity in each of the systems. The Cases selected are from Energy Audit
studies conducted in various industries and represent a true real life picture
of energy conservation potentials. Boilers are generally classified under three
categories: |
- Non – IBR (or coil type boilers)
- Package (or smoke tube IBR boilers)
- Large water tube boilers
|
Though the classification is based on the IBR regulations, it has a greater
significance from energy conservation angle. The energy conservation
opportunities associated with each of the above boilers are different, so are
the problems faced by the end users.
We have incorporated the case studies classifying them under the above
headings. The facts and figures are from actual field study measurement whereas
names of the company are not mentioned to maintain secrecy.
STEAM GENERATION
SYSTEM : |
The first and foremost activity to be conducted in the energy management
program is to evaluate the boiler efficiency. Format for collecting data for
boiler efficiency is enclosed as Appendix I and the Work sheet for evaluating
boiler efficiency from the collected Data. Fortunately the efficiency evaluation
procedure for all the boilers is same regardless of its classification.
Following is the boiler efficiency test conducted on a non-IBR boiler.
BOILER EFFICIENCY
EVALUATION CALCULATIONS (850 kg/hr) |
| Ultimate Analysis of fuel (w/w): |
| Type of fuel |
F.O. |
|
| C: |
82.98 |
% |
| H: |
12.38 |
% |
| S: |
2.77 |
% |
| N2: |
1.12 |
% |
| O2: |
0.74 |
% |
| Moisture: |
0.01 |
% |
| Ash: |
0.00 |
% |
| Specific Gravity of fuel |
0.92 |
kg/m3 |
| Gross Calorific value of fuel |
9944 |
kcal/kg f |
| Fuel Temperature |
115 |
°C |
|
| Flue gas analysis (v/v): |
Before Eco. |
After Eco. |
| CO2 % |
14.00% |
13.00% |
| N2 |
83.00% |
83.00% |
| O2 % |
3.00% |
4.00% |
| (Actual Measurements of CO2%
from observations) |
|
| Indirect Efficiency Test |
| Average feed water temp. |
74.00 |
°C |
| Average Steam Pressure |
10.50 |
kg/cm2 |
| Average combustion Air temp. |
29.00 |
°C |
| Flue gas temp. Before Eco. |
450.00 |
°C |
| Flue gas temp. After Eco. |
210.00 |
°C |
| (Actual measurements of temperature from observation
table) |
|
| |
Before Eco. |
After Eco. |
| Air ratio |
1.17 |
1.24 |
| Actual wet flue gas (kg/kg F) |
15.27 |
16.38 |
| Flue gas temperature |
450.00 |
210.00 |
| |
| % Dry gas loss |
15.45 % |
7.12 % |
| % Wet gas loss |
7.81 % |
6.47 % |
| Radiation losses |
2.00 % |
2.00 % |
| |
| Efficiency of boiler (Indirect) |
74.74 % |
84.40 % |
Direct Efficiency Test |
|
|
