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ENERGY AUDITat
Technoplast Ltd.Nairobi
on behalf of
Kenya Association of Manufacturers
by
Lean Energy Solutions, Nairobi
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Equipments at Technoplast
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Monthly Electricity Consumption (10-11)
MONTH
ELECTRICITY (KENYA POWER) Specific
energy
costKSh/kWhDemandkVA PowerFactor ConsumptionkWh Total BillKSh CostKSh/kWh
Load
Factor,%
JUL '10 137 0.98 35,542 496,642 13.97 37 13.97
AUG '10 151 0.97 61,222 801,321 13.09 58 13.09
SEP ,10 146 0.97 62,481 14,434 13.03 61 13.03
OCT '10 144 0.97 66,236 862,021 13.01 66 13.01
NOV '10 142 0.96 64,269 885,485 13.78 65 13.78
JAN '11 170 0.75 55,680 786,364 14.12 61 14.12
FEB' 11 144 0.97 60,705 879,523 14.49 60 14.49
MAR '11 161 0.99 54,894 877,203 15.98 48 15.98
APR '11 165 0.98 64,154 1,084,190 16.90 55 16.90
MAY '11 201 0.97 56,999 1,032,488 18.11 41 18.11
JUN '11 201 0.98 77,454 1,407,135 18.17 55 18.17
Total 659,636 9,926,807 15.05
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Approximate Break-up of Electricity
Consumption
Pulverisers58.6%
Roto MouldingMachines
17.9%
Cooling Tower Fan
& Pumps11.4%
Others12.1%
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Control Operation of Cooling Tower Fans
Existing Condition: Cooling water is used for cooling Pulverizing machines &
recycled plastic extruder. 1 no. primary pump circulates water
from the hot well to cold well through the cooling tower. 1 no.
secondary pump circulates water from the cold well to the plantand back to the hot well. Both pumps and fan are operating
continuously.
The cold well temperature in the cold well during normal
production time was observed to be varying from 23°C. Duringshift changeover, the cold well temperature was 17.5°C.
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Control Operation of Cooling Tower Fans
Recommendation: Install temperature controller for switching the cooling tower
fan ON or OFF depending on the cold well temperature. It is
recommended that the fan be switched ON when the cold well
water temperature is 30°C and switched OFF when thetemperature is 25°C. Considering the Nairobi ambient
conditions, it is likely that the cooling tower fan will remain
OFF for about 50% of the time.
Savings: 20,000 kWh/annum i.e. KShs 300,000 per annum
Investment for Temperature Controller: KShs 60,000.
Payback Period: 3 months
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Eliminate Primary Pump in Cooling Tower
Existing Condition: 1 no. primary pump circulates water from the hot well to cold
well through the cooling tower. 1 no. secondary pump
circulates water from the cold well to the plant and back to the
hot well. Both pumps and fan are operating continuously.
Recommendation:
Connect the return line of secondary pump to the top of cooling
tower and eliminate the primary pump.
Savings: 15,000 kWh/annum i.e. KShs 225,000 per annum
Investment: Negligible
Payback Period: Immediate
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IDO Composition & Calorific Value
IDO Composition & Calorific Value
Carbon 83.7 %
Hydrogen 13.1 %
1.8 %
Oxygen 0.5 %
Nitrogen 0.7
Ash 0.02
Moisture 0.25 %
Higher Heating Value of fuel 10700 kcal/kg
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Indirect Efficiency Oven No. 1%O2 in Flue Gas (before APH) 9.80 %
%CO2 in Flue Gas (before APH) 7.25 %
CO in Flue Gas (before APH) 35.00 ppm
Flue Gas Temp. (Tf ) 226.00 °C
Ambient Temp. (Ta) 22.00 °C
Humidity of air 0.010 kg/kg of dry air
Specific Heat of Flue Gas (Cp) 0.24 kcal/kg/°
Specific heat of fly ash 0.16kcal/kg°C
Calculations
Stoichiometric air requirement 14.05 kg of air/kg of fuel
Excess air 87.50 %
Actual air supplied 26.35 kg of air/kg of fuel
Unburnt Carbon in Ash 0.00 kg/kg of fuel
(1) Heat Loss Due to Dry flue Gas 14.87 %
(2) Heat Loss due to evaporation of water formed due to H2 in
fuel 7.43 %
(3) Heat loss due partial conversion of C to CO 0.02 %
(4) Heat loss due to moisture in air 0.23 %
(5) Heat loss due to moisture in fuel 0.02 %
(6) Heat Loss due to radiation & convection (assumed) 2.00 %
Oven Efficiency = 100 - (1+2+3+4) = 75.43 %
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Summary of Energy Efficiency of Ovens
& Expected Savings by Improved Sealing
(with door closed)
Roto
Moulding
Oven
Existing
Efficiency
Expected
Increase in
Efficiency
Remarks
Oven1 75.4% 2.2% Heavy leaks
near burner duct
Oven 3 68.5% 11.6%
Oven 4 71.7% 10.6%
Overall energy efficiency including door opening losses, heating of moulds from cold etc. is likely to be 10% to 40%, also depending on
the size of tanks.
Plug leakages and save about 33,000 litres of IDO per annum i.e. KShs
2.90 million, investment is minor.
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Wood or Agro Briquette Gasification
Down Draft Gasifier Producer Gas Burner
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Basics of Biomass Gasification
Calorific value of Biomass Briquettes : 3800 kcal/kg
Conversion efficiency: 60%
Calorific value of Producer Gas: 1100 -1200 kcal/m3
Quantity of producer gas produced: 2.0 m3/kg biomass
Existing Condition:
IDO is fired in the Roto Moulding Ovens for heating moulds
ECO: Replace IDO in Roto Moulding Ovens
with Gasified Wood or Agro Briquettes
Proposed:
Substitute IDO with Producer Gas produced in Biomass Gasifiers
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Existing IDO consumption: 330,000 litres/annumPrice of IDO: Kshs 88 per litre
Cost of IDO: KShs 29 million per annum
Expected agro briquette consumption: 1.5 million tonsPrice of agro briquette: Kshs 14 per kg
Cost of agro briquettes: KShs 21 million per annum
Saving: KShs 8 million per annum
Investment for Gasifier, gas piping & burners: KShs 30 million
Payback period: 4 years
ECO: Replace IDO in Roto Moulding Ovens
with Gasified Wood or Agro Briquettes