Sistem Satuan

Gas Alam

Oleh:

Prof.Dr.Ir. Slamet, MT Departemen Teknik Kimia

Fakultas Teknik, Universitas Indonesia

Depok, September 2015

Sistem Satuan

• The International System (SI)

• The English Customary Systems

• The Metric System

SI System

Metric System

English System

English (Gas)

Standard Reference Conditions

in Current Use (SI)

Temperature Absolute

pressure

Relative

humidity Publishing or establishing entity

°C kPa % RH

0 100.000 IUPAC (post-1997) [1]

0 101.325 IUPAC (pre-1997)

[1], NIST

[2], ISO

10780[3]

15 101.325 0 ISA [4]

, ISO 13443[5]

, EEA [6]

, EGIA [7]

20 101.325 EPA [8]

, NIST [9]

25 101.325 EPA [10]

25 100.000 SATP [11]

20 100.000 0 CAGI [12]

15 100.000 SPE [13]

Standard Reference Conditions

in Current Use (English)

°F psia % RH Publishing or establishing entity

60 14.696 SPE [13]

, OSHA [14]

, SCAQMD [15]

60 14.73 EGIA [7]

, OPEC [16]

, EIA [17]

59 14.503 78 Army Standard Metro [18]

59 14.696 60 ISO 2314, ISO 3977-2[19]

Publishing or establishing entity

• IUPAC: International Union of Pure and Applied Chemistry

• NIST: National Institute of Standards and Technology

• ISA: ICAO's International Standard Atmosphere

• ISO: International Organization for Standardization

• EEA: European Environment Agency

• EGIA: Electricity and Gas Inspection Act (of Canada)

• EPA: U.S. Environmental Protection Agency

• SATP: Standard Ambient Pressure and Temperature

• CAGI: Compressed Air and Gas Institute

• SPE: Society of Petroleum Engineers

• OSHA: U.S. Occupational Safety and Health Administration

• SCAQMD: California's South Coast Air Quality Control District

• OPEC: Organization of Petroleum Exporting Countries

• EIA: U.S. Energy Information Administration

• Std. Metro: U.S. Army's Standard Metro (used in ballistics)

Penulisan Kondisi Standar

1 std ft3 (© 60oF dan 14.7 psia) =

0.0286 std m3 (© 15oC dan 100 kPa)

• Satuan Inggris

• M (dari angka Romawi) = 1000

• MM = 1 000 000

• MMscf atau MMSCF atau MMCF = 106 std cu ft

• Satuan SI

• M singkatan dari “mega” = 106

• Untuk menghindari kebingungan: satu juta meter kubik standar

ditulis 106 std m3

Inisial M

Konversi Volumetrik-Massa: GAS

)dm std x(101739m std 10

kmol 740 41.

h 24

d.

d

m std 10kmol/h 36

36

36

(MMscf/d) 110MMscf

lbmol 2636.

hr 24

day.

day

MMscflbmol/hr x

lb/hr = (lb-mol/hr)(MW gas) = 110 x(MMscf/d)x(MW gas)

gg x )./dm std (1050400.m std 10

udara kg 06)1.21(E.

h 24

d.

d

m std 10kg/h 36

36

36

g = ( gas)/( udara) = (M gas)/(M udara)

Tekanan

• Tekanan absolut banyak digunakan di banyak perhitungan

• Di satuan Inggris digunakan penambahan „a‟: „psia‟ atau „psfa‟

• Di SI tidak ditulis, P = 138 kPa menunjukkan tekanan absolut

• Tekanan di meteran: penambahan akhiran „g‟

• Inggris: ditulis „psig‟ atau „psfg‟

• SI: ditulis misalnya P = 37 kPa(g)

• 1 Pascal (Pa) = 1 N/m2

• 1 bar = 14.5 psi = 0.987 atm = 1.02 kg/cm2

= 100 000 N/m2 = 100 kPa

• 1 psi = 6.89 kPa

• 14.696 psia = 1 atm (std) = 101.325 kPa = 1.01 bar = 1.03 kgf/km2

luassatuan

GayaTekanan

Contoh

• Meteran tekanan pada tangki CO2 yang digunakan

untuk mengisi botol-botol air soda menunjukkan

angka 51 psi. Pada saat yang sama barometer

membaca 28.0 in Hg. Berapa tekanan absolut di

dalam tangki (psia)?

Penyelesaian

• Tekanan absolut =

tekanan meteran + tekanan atmosfir (barometer)

• Basis: Tekanan barometer = 28.0 in. Hg

• Tekanan atmosfir =

(28.0 in. Hg) x (14.7 psia/29.92 in. Hg) = 13.76 psia

• Tekanan absolut di tangki = 51.0 + 13.76 = 64.76 psia

Konstanta Gas Ideal

ZRTPV P V T R

kPa m3 K 8.314 (kPa)(m3)/(kmol)(K)

MPa m3 K 0.008314 (MPa)(m3)/(kmol)(K)

bar m3 K 0.08314 (bar)(m3)/(kmol)(K)

psi ft3 oR 10.7316 (psia)(ft3)/(lb-mol)(oR)

lb/ft2 ft3 oR 1 545 (lbf)(ft)/(lb-mol)(oR)

atm m3 K 8.2057459 x 10-5 (atm)(m³)/(mol)(K)

mmHg L K 62.3637 (mmHg)(L)/(K)(mol)

1.987 cal / (K)(mol)

Volume, Gravitasi dan Massa

VOLUME :

• 1 ft3 = 0.0283 m3 = 7.48 US gal. = 6.23 UK gal.

• 1 bbl = 0.159 m3 = 5.61 ft3 = 42 US gal. = 35 UK gal.

GRAVITASI: percepatan jatuh-bebas di dalam medan gravitasi bumi

• g = 9.80665 m/det2

• Faktor proporsional Newton (gc) = 32.174 lb-ft/det2-lbf

Massa:

• 1 grain (gr) = 64.79891 milligrams (mg) – SI

• 1 gram (g) = 15.43236 grain (gr)