4C.1 Emission Rate Calculations

Submerged Combustion Vaporizers (SCVs)

Total emissions: NO_x = 51 tonnes/yr and CO = 257 tonnes/yr (provided by Vendor’s equipment information, emissions are based upon 30 t/hr and flue gas produced per 100 t/hr LNG vaporization)

No. of SCVs = 5

Emission rate of each SCV:

NO_x = (51 tonnes / 365 days / 24 hours / 3600 s) x 1x10⁶ / 5 = 0.32 g/s

CO = = (257 tonnes / 365 days / 24 hours / 3600 s) x 1x10⁶ / 5 = 1.63 g/s

Total flowrate = 130,000 Nm³hr^-1 (at 0 °C & 101.3 kPa)

At exhaust temperature of 30 °C, the total flowrate = 144,285.71 m³hr^-1

Stack velocity of each SCV = 144,285.71 / 5 / 3600 / (p x 0.6²) = 7.09 ms^-1

LNG Carrier – Auxiliary Engines

· Total generator capacity = 9,350 kW (under 75% load factor)

· Generator load factor = 75%

· Burning Marine Diesel Oil (MDO) or Heavy Fuel Oil (HFO)

According to IMO MARPOL Annex VI, NO_x is limited by the formula:

45.0 x rpm^-0.2 g/kWh

The auxiliary generator will be operating at 720 rpm and therefore, NO_x emission will be 12.07 g/kWh. At 75% load, the NO_x can vary from 7% to 15% and therefore, upper limit of NO_x emission will be 12.07 x 1.15 = 13.88 g/kWh.

NO_x g emission factor = 13.88 g/kWh

SO₂ emission factor = 6 g/kWh (based on 1.5% sulphur content)

CO emission factor = 0.6 /kWh

Emission rate from one chimney:

NO_x = (13.88 g/kWh x 9,350 kW) / 3600 = 36 g/s

SO₂ = (6 g/kWh x 9,350 kW) / 3600 = 15.6 g/s

CO = (0.6 g/kWh x 9,350 kW) / 3600 = 1.56 g/s

As 3 individual stacks are enclosed in a single chimney, therefore, effective diameter = 0.78 m

Exhaust gas velocity = 25 ms^-1

Exhaust temperature = 320 °C

Pipeline Gas Heater

Total emissions : 72 tonnes of NO_x and 45 tonnes of CO a year (based on 4.1 MMSCFD for the Design Case)

Total no. of stack = 4

Emission rate of each stack:

NO_x = (72 tonnes / 365 days / 24 hours / 3600 s) x 1x10⁶ /4 = 0.57 g/s

CO = (45 tonnes / 365 days / 24 hours / 3600 s) x 1x10⁶ / 4 = 0.36 g/s

Total flowrate = 73,900 Nm³hr^-1 (at 0 °C & 101.3 kPa)

At exhaust temperature of 280 °C, the total flowrate = 149,695 m³hr^-1

Stack velocity = 149,695 / 3600 / 4 / (p x 0.54²) = 11.56 ms^-1

Summary of Modelling Parameters

	SCV	LNG Carrier – Auxiliary Engine	Pipeline Gas Heater
No. of Emission Sources	5	1	4
Stack Height (m)	13	41	15
Stack Diameter (m)	1.2	0.78	1.07
Exit Temperature (°C)	30	320	280
Exit Velocity (m/s)	7.09	25	11.56
NOx Emission Rate (g/s)	0.32	36	0.57
SO2 Emission Rate (g/s)	-	15.6	-
CO Emission Rate (g/s)	1.63	1.56	0.36