GAS PROCESSING TECHNOLOGY (TKK 564) Instructor: Dr. Istadi (http://tekim.undip.ac.id/ staf/istadi ) Email:
[email protected]
Instructor’s Background ! BEng. (1995): Universitas Diponegoro ! Meng. (2000): Institut Teknologi Bandung ! PhD. (2006): Universiti Teknologi Malaysia ! Specialization: ! Catalyst Design for Energy Conversion ! Chemical Process Design for Energy Conversion ! Plasma Chemical Reactor Design for Energy Conversion
Course Syllabus: (Part 1) 1.
2.
3.
4. 5. 6. 7.
Definitions of Natural Gas, Gas Reservoir, Gas Drilling and Gas production (Pengertian gas alam, gas reservoir, gas drilling, dan produksi gas) Overview of Gas Plant Processing (Overview Sistem Pemrosesan Gas) and Gas Field Operations and Inlet Receiving (Operasi Lapangan Gas dan Penerimaan Inlet) Gas Treating: Chemical Treatments (Pengolahan Gas: secara kimia) and Sour Gas Treating (Pengolahan Gas Asam) Gas Treating: Physical Treatments (Pengolahan Gas: secara fisika) Gas Dehydration (Dehidrasi Gas) Gas Dehydration (Dehidrasi Gas) Hydrocarbons Recovery (Pengambilan Hidrokarbon)
Course Syllabus: (Part 2) 1. Gas Compression System 2. Nitrogen Rejection and Trace Component Removal 3. 4. 5. 6. 7. 8.
(Penghilangan Nitrogen dan Komponen lainnya) Natural Gas Liquid Processing and Sulfur Recovery (Pemrosesan Cairan Gas Alam dan Penghilangan Sulfur) Gas Transportation and Storage (Transportasi dan Penyimpanan Gas) Liquified Natural Gas #1 (Gas Alam Cair) Liquified Natural Gas #2 (Gas Alam Cair) Second Assignment Ujian Akhir Semester
SISTEM UJIAN ! TUGAS (assignment) (bobot nilai: 10). Bentuk online
quiz assignment
! UJIAN TENGAH SEMESTER (bobot nilai: 40).
Bentuk soal pilihan ganda
LITERATURES 1. A. J. Kidnay, W.R. Parrish, (2006),
Fundamentals of Natural Gas Processsing, Taylor & Francis Group, Boca Raton
2. H.K. Abdel-‐Aal, M. Aggour, and M.A. Fahim,
(2003). Petroleum and Gas Field Processing. Marcel Dekker, Inc., New York.
Definitions of Natural Gas, Gas Reservoir, Gas Drilling, and Gas production (Pengertian gas alam, gas reservoir, gas drilling, dan produksi gas) Week #1
DefiniBons of Natural Gas, Gas Reservoir, Gas Drilling, and Gas ProducBon ! What is Natural Gas? ! The gas obtained from natural underground reservoirs either as free gas or gas associated with crude oil ! Contains large amounts of methane (CH4) along with decreasing amounts of other hydrocarbon ! Impurities such as H2S, N2, and CO2 are often found with the gas ! generally comes saturated with water vapor.
Why are Oil and Gas so Useful? ! Oil is liquid. Meaning that oil may be transported
and delivered through pipe ! The primary use of natural gas is as a fuel, it is also a source of hydrocarbons for petrochemical feedstocks and a major source of elemental sulfur ! Natural gas presents many environmental advantages over petroleum and coal ! Carbon dioxide, a greenhouse gas linked to global warming, is produced from oil and coal at a rate of about 1.4 to 1.75 times higher than from natural gas
Pollutants per Billion Btu of Energy
Primary Sources of Energy in the World in 2003
Major proven natural gas reserves by country
United States energy consumpBon by fuel
Source of Natural Gas (Gas Reservoirs) ! Conventional natural gas generally occurs in deep
reservoirs ! either associated with crude oil (associated gas) or in reservoirs that contain little or no crude oil (non associated gas) ! Associated gas is produced with the oil and separated at the casinghead or wellhead. ! Gas produced in this fashion is also referred to as casinghead gas, oilwell gas, or dissolved gas. ! Nonassociated gas is sometimes referred to as gas-‐well gas or dry gas. However, this dry gas can still contain significant amounts of NGL components. ! Roughly 93% of the gas produced in the United States is nonassociated
Natural Gas ComposiBons ! Water is almost always present at wellhead
conditions but is typically not shown in the analysis ! Unless the gas has been dehydrated before it reaches the gas processing plant, ! the common practice is to assume the entering gas is saturated with water at the plant inlet conditions.
Typical gas ComposiBons
Typical ComposiBon of Indonesian Gas
Processing and Principal Products ! Two primary uses of natural gas: ! As a fuel ! As a petrochemical feedstock ! Three reason of natural gas processing: ! Purification. Removal of materials, valuable or not, that inhibit the use of the gas as an industrial or residential fuel ! Separation. Splitting out of components that have greater value as petrochemical feedstocks, stand alone fuels (e.g., propane), or industrial gases (e.g., ethane, helium) ! Liquefaction. Increase of the energy density of the gas for storage or transportation ! What is different of Purification and Separation?
Generic Raw Gas and Product Slate
Product SpecificaBons ! Natural Gas: ! The composition of natural gas varies considerably from location to location, and ! as with petroleum products in general, the specifications for salable products from gas processing are generally in terms of both composition and performance criteria ! For natural gas these criteria include: Wobbe number, heating value, total inerts, water, oxygen, and sulfur content. ! The first two criteria relate to combustion characteristics. ! The latter three provide protection from pipeline plugging and corrosion.
SpecificaBons for Pipeline Quality Gas
Liquid product SpecificaBon ! As with gases, specifications for liquid products are
based upon both composition and performance criteria. ! For liquid products, the performance specifications include: Reid vapor pressure, water, oxygen, H2S, and total sulfur content. ! Safety considerations make vapor pressure especially important for the liquid products because of regulations for shipping and storage containers.
CombusBon CharacterisBcs ! Natural gas is as a fuel ! pipeline gas is normally bought on the
basis of its heating value ! Determination of the heating value of a fuel involves two arbitrary but conventional standard states for the water formed in the reaction: ! All the water formed is a liquid (gross heating value, frequently called higher heating value [HHV]) ! include latent heat of vaporization of water ! All the water formed is a gas (net heating value, frequently called lower heating value [LHV]) ! HHV-‐ latent heat of vaporization of water ! The heating value is normally calculated at 60°F and 1 atm (15.6°C and 1.01 atm), standard conditions for the gas industry, and, thus at equilibrium, the water would be partially liquid and partially vapor.
Hea9ng Value ….
! Heating values for custody transfer are determined either
by direct measurement, in which bomb calorimetry is used, or by computation of the value on the basis of gas analysis. ! The formulas for the calculation of ideal gas gross heating values, on a volumetric basis are (Gas Processors Association, 1996):
! The equations assume that the gas analysis is given on a
dry basis, that water is xW when the gas is saturated at the specified conditions.
! The mole fraction can be calculated from:
! The vapor pressure of water at 60°F (15.6°C), the common base
temperature, is 0.25636 psia (1.76754 kPa). ! The most commonly used base pressures, Pb, and the values of (1− xW) are listed below.
Contoh Perhitungan HV
! Example 1.2 Calculate the heating value of the Alberta gas given in Table 1.4.
Assume the heating value for the butanes to be that of isobutene, and for the C5+ fraction, use pure hexane. ! Table 1.10 shows the calculations with heating values obtained from Appendix B. This mixture has a gross heating value of 1,202.2 Btu/scf (44,886 kJ/Sm3). Note that credit is not given for the heating value associated with H2S in contractual situations. It is unlikely that a gas stream with 3.3% H2S would be burned.
Wobbe Number ! In gas appliances, maintenance of the same combustion
characteristics are desirable when one gas composition is switched to another. ! one of the more important considerations is maintenance of the same heat release at the burner for a given pressure drop through a control valve. ! This combustion characteristic is measured by the Wobbe number ! Wobbe Number is defined as the gross heating value (Btu/scf) of the gas divided by the square root of the specific gravity (the ratio of the density of the gas divided by the density of air; both densities evaluated at the same pressure and temperature).
! Two gases with the same Wobbe number are interchangeable as far as
heat release at the burner is concerned. ! Formula for Wobbe Number: ! WB = (gross heating value)/(specific gravity)^1/2 ! The Wobbe number normally has a value between 1,100 and 1,400 ! Some typical Wobbe numbers are:
! THANKS YOU
Definitions of Natural Gas, Gas Reservoir, Gas Drilling, and Gas Production (Pengertian gas alam, gas reservoir, gas drilling, dan produksi gas)
DefiniBons of Natural Gas, Gas Reservoir, Gas Drilling, and Gas ProducBon ! What is Natural Gas? ! Merupakan gas yang diperoleh dari reservoir alami bawah tanah baik sebagai gas bebas maupun sebagai gas yang berkaitan dengan crude oil ! Mengandung sebagian besar gas methane (CH4) dan hidrokarbon lainnya dalam jumlah sedikit ! Mengandung impuritas seperti H2S, N2, dan CO2 yang bercampur dengan gas alam tersebut ! Pada umumnya jenuh dengan uap air
Why are Oil and Gas so Useful? ! Oil is liquid, Natural Gas is gas. Minyak dan gas
didistribusikan atau ditransportasikan melalui pipa atau truk tanki ! Penggunaan utama minyak dan gas alam adalah untuk bahan bakar atau fuel. ! Minyak dan gas alam juga dimanfaatkan sebagai sumber-‐sumber hidrokarbon untuk feedstock petrokimia sumber unsur belerang (sulfur) ! Natural gas mempunyai lebih banyak environmental advantages dibandingkan minyak dan batubara
Pollutants per Billion Btu of Energy
Primary Sources of Energy in the World in 2003
Major proven natural gas reserves by country
United States energy consumpBon by fuel
Source of Natural Gas (Gas Reservoirs) ! Pada umumnya, gas alam konvensional diperoleh di dalam
deep reservoirs ! Sumber gas alam tersebut berada bersamaan dengan crude oil (associated gas) ! atau di dalam reservoir yang mengandung sedikit atau bahkan tanpa crude oil (non associated gas) ! Associated gas diproduksi bersamaan dengan crude oil dan dipisahkan di casinghead atau wellhead. Gas yang diproduksi seperti ini disebut juga dengan casinghead gas, oilwell gas, or dissolved gas. ! Non-‐associated gas kadang-‐kadang disebut juga dengan gas-‐ well gas atau dry gas. Walaupun demikian gas ini masih juga mengadnung sejumlah komponen NGL (natural gas liquid). ! Di USA: 93% gas yang dihasilkan di United States adalah non-‐associated
SchemaBc overview of natural gas industry
Natural Gas ComposiBons ! Water atau air selalu ada di dalam kondisi wellhead
tetapi pada umumnya tidak tampak di dalam analisis. Biasanya air bercampur dengan gas dalam kondisi jenuhnya. ! Oleh karena itu, dalam prosesnya gas didehidrasi awal dulu sebelum gas tersebut dibawa ke unit pemrosesan gas ! Pada prakteknya, gas masuk dari well biasanya dalam keadaan saturated with water
Typical gas ComposiBons
Typical gas ComposiBon in Indonesia
Processing and Principal Products ! Penggunaan Utama Gas Alam: ! Sebagai bahan bakar (fuel) ! Sebagai feedstock petrokimia ! Tiga Alasan Pemrosesan Gas Alam: ! Purification (Pemurnian): penghilangan beberapa material, baik yang bernilai maupun yang tidak, yang dapat menghambat penggunaan gas tersebut di industri atau perkotaan ! Separation (Pemisahan): Memisahkan komponen-‐komponen yang mempunyai nilai lebih besar sebagai feedstock petrokimia, sebagai bahan bakar (propane), atau sebagai gas-‐gas industri (e.g., ethane, helium) ! Liquefaction. Increase of the energy density of the gas for storage or transportation ! What is different of Purification and Separation?
Generic Raw Gas and Product Slate
Gas Product SpecificaBons ! Natural Gas: ! Komposisi gas alam sangat bervariasi dari lokasi ke lokasi ! Spesifikasi gas alam bisa juga meliputi: ! Wobbe number, ! heating value, ! total inerts, ! water, ! oxygen, ! and sulfur content. ! Dua kriteria pertama di atas menyangkut karakteristik dari pembakarannya. ! Tiga kriteria terakhir menyangkut proteksi di dalam sistem pemipaannya (pipeline) , misalnya plugging dan korosi
SpecificaBons for Pipeline Quality Gas
Liquid Product SpecificaBon ! Seperti halnya gas alam, spesifikasi produk cair
tergantung kepada kriteria komposisi dan performance ! Untuk produk cair, performance meliputi: Reid vapor pressure, water, oxygen, H2S, dan total sulfur content. ! Pertimbangan Safety menyarankan bahwa tekanan uap merupakan parameter penting untuk produk cair, karena persyaratan pada regulasi pengapalan dan penyimpanan di dalam kontainer
CombusBon CharacterisBcs ! Natural gas sebagai fuel ! pipeline gas biasanya dijual dalam basis
nilai heating value, misalnya: MMBtu/cuft ! Heating Value didefinisikan sebagai energi termal per satuan volume gas (Btu/cuft). Gas alam biasanya mengandung heating value: 900 – 1200 Btu/ft3 ! Ada dua macam Heating Value yang digunakan di industri, yaitu: ! Semua air yang ada adalah cair dinamakan higher heating value [HHV] atau gross heating value ! termasuk latent heat of vaporization of water ! Semua air yang ada adalah berupa gas dinamakan lower heating value [LHV] atau net heating value ! sama dengan (HHV-‐ latent heat of vaporization of water) ! Heating Value normalnya dihitung pada suhu 60°F dan tekanan 1 atm (15.6°C ; 1.01 atm), keadaan standard di industri gas, dan pada kesetimbangan, sebagian air berfasa cair dan sebagian lagi berfasa uap.
HeaBng Value …. ! Heating values ditentukan melalui eksperimen atau
pengukuran langsung menggunakan bomb calorimeter, atau melalui perhitungan berdasarkan analisis gasnya ! Formula untuk menghitung ideal gas gross heating values (on a volumetric basis ) (Gas Processors Association, 1996):
! Persamaan di atas diasumsikan bahwa analisis gas
diberikan pada basis kering, dimana air (xW) jika gas jenuh pada kondisi tersebut.
! Fraksi mol air (xw) dapat dihitung dari:
! Tekanan uap air pada 60°F (15.6°C), adalah: 0.25636 psia (1.76754 kPa). ! Base pressures, Pb, dan nilai (1− xW) adalah.
Contoh Perhitungan HV ! Example 1.2 Calculate the heating value of the Alberta gas given in Table 1.4.
Assume the heating value for the butanes to be that of isobutene, and for the C5+ fraction, use pure hexane. ! Table 1.10 shows the calculations with heating values obtained from Appendix B. This mixture has a gross heating value of 1,202.2 Btu/scf (44,886 kJ/Sm3). Note that credit is not given for the heating value associated with H2S in contractual situations. It is unlikely that a gas stream with 3.3% H2S would be burned.
Wobbe Number ! Dalam implementasi penggunaan gas dalam pembakaran,
karakteristik pembakaran antara komposisi gas yang satu dan yang lain harus konsisten, apalagi jika gas-‐gas yang digunakan berubah komposisinya. ! Satu hal yang harus konsisten adalah kesamaan panas yang dikeluarkan dari burner pada pressure drop tertentu melalui control valve. ! Karakteristik pembakaran seperti ini ditentukan dengan Wobbe number ! Wobbe Number didefinisikan sebagai gross heating value (Btu/scf) dari gas sample dibagi dengan akar kuadrat specific gravity (density gas dibagi dengan density udara; pada tekanan dan suhu yang sama).
! Two gases with the same Wobbe number are
interchangeable as far as heat release at the burner is concerned. ! Formula for Wobbe Number: ! WB = (gross heating value)/(specific gravity)^1/2 ! The Wobbe number normally has a value between 1,100 and 1,400 ! Some typical Wobbe numbers are:
