1- Feedstock Composition
The feed gas composition for the NIOC LNG Project is shown below.
| Carbon Dioxide | 2.53 |
| Water | 0.052 |
| Nitrogen | 4.56 |
| Hydrogen Sulphide | 1.1 |
| Methane | 83.215 |
| Ethane | 5.06 |
| C3+ | 3.483 |
| Total | 100 |
2.7 | Carbonyl sulphide |
229 | Mercaptans |
900 ng/Nm3 | Mercury |
2- Feedstock Pressure and Temperature
(1) Pressure
The feed gas from battery limit to Feed Gas Metering Unit-11 has a normal pressure of 75 bara. During upset or alternative operating conditions, the feed gas pipeline pressure may be changed from normal operating pressure.
(2) Temperature
The arrival temperature of the feed gas varies with the seasons and is fixed at a minimum of 13 ˚C during winter and at a maximum of 27 ˚C during the summer. The average temperature is 20 ˚C.
3- Capacity Consideration
The Liquefaction Units have been optimized to produce LNG at an ambient temperature of 29 C and sea water temperature of 28 C, using electric motors, where power will be supplied from Power Station.
4- Product Specification
4.1 LNG Specification
High Heating Value (HHV) 1050 BTU/SCF (min.)
1100 BTU/SCF (max.)
Methane 85 mol % (min.)
Nitrogen 1.0 mol % (max., Note 1)
Butanes and heavier 1.75 mol % (max.)
Pentanes and heavier 0.1 mol % (max.)
H2S 4.8 mg/Sm3 as S (max.)
Mercaptans 6.9 mg/Sm3 as S (max.)
Total Sulfur 28 mg/Sm3 (max.)
Note 1: To LNG Carrier
2: Sm3 = Standard cubic meter (1.013 bara and 60 ˚F)
4.2 LPG Specification
The following are the specifications of the commercial grade Propane and Butane products.
(1) Propane
| Composition | | |
| | - Ethane content | : | 2.0 liquid volume % (max.) |
| | - Propane content | : | 96 liquid volume % (min.) |
| Quality | | |
| | - Vapor pressure at 100 F | : | 200 psig (max.) |
| | - Volatile residue temp. at 95% evaporation | : | -37 ˚F (max.) |
| | or | | |
| | Butane and heavier | : | 2.5 % liquid volume % (max.) |
| | - Residue on evap. of 100 cm3 | : | 0.04 cm3 (max.) |
| | - Oil stain observation | | pass |
| | - Corrosion, copper strip | | No. 1 |
| Impurities | | |
| | - Total sulphur | : | 0.001 wt % (max.) |
| | - Hydrogen Sulphide | : | negative |
| | - Moisture | : | |
(2) Butane
| Composition | | |
| | - Butane Content | : | 95 liquid volume % (min.) |
| | - Pentane and heavier | : | 1.0 mole % (max., Note 1) |
| Quality | | |
| | - Vapor pressure at 100 ˚F | : | 70 psig (max.) |
| | - Volatile residue temp. at 95% evaporation | : | 36 ˚F (max.) |
| | - Corrosion, copper strip | : | No. 1 |
| Impurities | | |
| | - Total sulphur | : | 0.001 wt% (max.) |
| | - Hydrogen Sulphide | : | Negative |
| | - Moisture | : | 1 ppmv (Note 1) |
Note 1: In order to allow Butane reinjection into LNG
4.3 Condensate Specification
Condensate product (C5+) from the bottom of the debutanizer will be mixed with the stabilized condensate produced in the upstream unit which is the scope of work of POGC (Pars Oil and Gas Company). Maximum C4 content is i-C4 + n-C4 : 0.5 mol% max and RVP at 100 oF ,10 psia in summer and 12 psia in winter.
4.4 Sulfur Specification
Purity : higher than 99.8 % wt
H2S : less than 10 ppm wt
Humidity : less than 0.1 % wt
Color : Bright yellow
