dpk02 - tahapan pendirian pabrik
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tahapan pendirian pabrikTRANSCRIPT
Tahap Pendirian Pabrik Kimia
Disain Pabrik Kimia
Profesi Sarjana Teknik Kimia ?
Di Industri sarjana Teknik Kimia sebagai : Proses Engineer Project Engineer Manager/Director/Supervisor
TAHAPAN PENDIRIAN PABRIK KIMIA
Skala Laboratorium Skala PilotSkala Pabrik
TAHAPAN PENDIRIAN PABRIK KIMIA
Industri kimia umumnya berskala besar (pabrik). (Skala industri >>> skala laboratorium). Pabrik kimia bisa dikembangkan dari proses
skala laboratorium dan ini memerlukan sejumlah tahapan pengembangan,
Pabrik kimia bisa merupakan pengembangan dari pabrik yang sudah ada.
Tahapan pengembangan yang diperlukan tentunya berbeda.
Tidak ada batasan yang ketat tentang tahapan-tahapan pengembangan proses skala laboratorium menjadi skala industri.
TAHAPAN PENDIRIAN PABRIK KIMIA Menurut simposium American Institute of Chemical Engineers (A.I.Ch.E.)
1. Penelitian Exploratif (Exploratory Research) / Penelitian Fundamental (Fundamental Research)
2. Penelitian Proses (Process Research)3. Pengembangan Proses (Process Development)4. Teknik Proses (Process Engineering)5. Analisis Ekonomi (Economic Analisys)6. Teknik Proyek (Project Engineering)7. Teknik Konstruksi (Construction Engineering)8. Teknik Operasi (Operational Engineering)9. Teknik Penelitian Pasar (Market Research
Engineering).
Penelitian exploratif
Penelitian exploratif adalah penelitian dalam rangka usaha-usaha pembuatan suatu bahan kimia baru, penggunaan bahan baku baru, proses baru, katalisator atau pelarut yang baru,dan sebagainya. Termasuk juga penelitian mengenai struktur
bahan kimia dan mekanisme reaksi. Penelitian jenis ini banyak dilakukan di
perguruan tinggi dan lembaga penelitian pada skala laboratorium.
Hasil penelitian exploratif ini, kemungkinan untuk layak secara teknik dan ekonomis pada skala industri adalah 1 : 100.
Penelitian fundamental Penelitian fundamental bertujuan untuk mencari
nilai besaran-besaran fisis atau kimia (kapasitas panas, panas reaksi, tetapan kecepatan reaksi, dan lain-lain), persamaanpersamaan fungsional misalnya d’Archy untuk aliran fluida dalam pipa, dan juga pengembangan teori yang berlaku umum (relatif). Penelitian ini berorientasi kuantitatif. Hasil penelitiannya bisa bermanfaat untuk
tahap-tahap pengembangan pabrik selanjutnya dan juga bermanfaat untuk memperkaya teori (aspek ilmiah).
Penelitian ini juga dilakukan oleh ahli teknik kimia maupun profesi-profesi lain.
Penelitian proses
Penelitian proses bertujuan untuk mencari data yang cukup dan secukupnya saja untuk tahap pengembangan proses (perancangan pilot plant) atau perancangan pabriknya.
Penelitian dimulai dengan mencoba merancang pabriknya dan membayangkan perancangan alat-alat yang akan dipakai. Perhitungan untuk perancangan tersebut memerlukan data/informasi. Sedangkan data/informasi sudah tersedia di pustaka atau bisa didekati dengan cara-cara tertentu. Namun sebagai lainnya tidak tersedia di pustaka atau tidak bisa didekati.
Selanjutnya dirancang penelitian proses untuk mencari data/informasi yang kurang tersebut. Jadi jelas penelitian proses bisa dijalankan setelah dibayangkan pabrik dan perancangannya.
Setelah tahap ini, kemungkinan kelayakannya untuk skala industri adalah 1 : 10.
Penelitian proses
Simposium A.I.Ch.E. tersebut menurut Soegiarto (1992), menyebutkan bahwa pengembangan proses meliputi kegiatan :a. Perencanaan kegiatan selanjutnya.b. Perancangan pilot plantc. Operasi pilot plantd. Pengolahan data pilot plant untuk
keperluan tahap-tahap selanjutnya (perancangan pabrik)
Pilot plant
Pilot plant adalah suatu unit pemroses yang lengkap seperti pabriknya namun berskala kecil. Harga pilot plant ini cukup mahal, adakalanya $ 2 juta.
Karena mahalnya biaya pilot plant, tahap ini sering diusahakan untuk dilompati.
Untuk proses-proses yang cukup dikenal, hal itu bisa.
Kemungkinan kelayakan secara teknis dan ekonomis untuk skala industri setelah pilot plant adalah 1 : 2 atau 5.
Teknik proses (Process Engineering) Teknik proses adalah perancangan proses
untuk pabriknya. Perancangan ini meliputi deskripsi proses, kebutuhan bahan dan energi (neraca massa dan energi), kebutuhan dan penyediaan utilitas, jenis dan ukuran alat-alat proses serta spesifikasinya, kondisi operasi, material untuk konstruksi, prinsip pengendalian proses, dan lain-lain.
Kegiatan ini memerlukan bekal kemampuan yang paling menyeluruh dari ahli teknik kimia.
Dapat dikatakan bahwa kegiatan ini menjiwai kegiatan pada tahap-tahap lainnya.
Analisis Ekonomi
Tahap berikutnya adalah analisis ekonomi. Hasilnya adalah kebutuhan modal, biaya produksi dan pengeluaran umum, keuntungan dan nilai parameter kelayakan ekonomi (Return on Investment, Pay Out Time, Break Even Point, Discounted Cash Flow, dan lain-lain) serta analisis sensitivitas dan sebagainya.
Jadi dapat disimpulkan apakah pabrik yang dirancang menarik dari segi ekonomi.
Analisis ekonomi pada tahap ini sudah cukup teliti karena perancangan proses pabriknya sudah selesai.
Namun perlu dicatat bahwa analisis ekonomi secara kasar harus selalu dilakukan pada tahap-tahap sebelumnya, sehingga kalau pabrik tidak menarik dari segi ekonomi, tahap pengembangan dihentikan seawal mungkin, agar tidak perlu dijalankan tahap-tahap lebih lanjut yang membutuhkan biaya besar.
Kemampuan melakukan analisis ekonomi pabrik baik secara kasar sampai cukup teliti perlu dikuasai oleh ahli teknik kimia.
Teknik Proyek (Project
Engineering) Tahap selanjutnya, yaitu teknik proyek,
dimaksudkan untuk menjembatani informasi proses menjadi informasi konstruksi.
Dapat dikatakan bahwa sebelum teknik proyek, segala sesuatunya masih dipikirkan sebagai proses, namun sesudah teknik proyek, dipikirkan sebagai pabrik.
Pada tahap teknik proyek, tenaga ahli proses bekerja sama dengan tenaga ahli konstruksi untuk merundingkan konstruksi yang feasible.
Teknik Konstruksi (Construction
Engineering) Pada tahap teknik konstruksi, dirancang
konstruksi alat secara detail (termasuk mechanical design), juga termasuk platform, fondasi, dan lain-lain, serta proses pendirinnya.
Setelah itu dilakukan konstruksi pabriknya. Pada tahap ini, tenaga ahli teknik kimia memantau kegiatannya, untuk melihat apakah proses konstruksi sudah sesuai dengan perancangan prosesnya.
Teknik Operasi(Operation
Engineering) Setelah pabrik didirikan, dilakukan teknik operasi,
yaitu menjalankan pabrik. Pada tahap ini, optimalisasi dan penyempurnaan
selalu dilakukan, karena umumnya pabrik tidak bisa terancang tepat pada kondisi optimumnya.
Peningkatan kapasitas dimungkinkan pula pada tahap ini. Sering dijumpai bahwa pabrik bisa ditingkatkan kapasitasnya menjadi lebih tinggi dari kapasitas terancangnya.
Keahlian teknik kimia juga sangat diperlukan pada tahap operasi. Selama pabrik beroperasi, umumnya dijumpai pula hambatanhambatan teknis yang perlu diatasi juga oleh ahli teknik kimia.
Teknik penelitian pasar(Market Research Engineering)
Teknik penelitian pasar bertujuan mengetahui kebutuhan masyarakat dan sekaligus peluang pasar untuk produk baru atau penyempurnaan produk pabrik yang sudah berjalan.
Dari kegiatan ini bisa muncul ide untuk memodifikasi pabrik yang sudah atau ide untuk mengembangkan pabrik baru.
Tahapan-tahapan yang lengkap
Tahapan Pendirian Pabrik Tahapan-tahapan yang lengkap seperti di muka, umumnya
dilaksanakan untuk pabrik dengan proses baru yang dikembangkan di laboratorium. Untuk proses yang sudah agak dikenal, sebagian tahapan bisa dilompati, sehingga lebih hemat dari segi waktu dan biaya.
Untuk bisa memanfaatkan secara optimal bahan mentah Indonesia untuk kesejahteraan rakyat, kemampuan untuk mengembangkan sendiri pabrik-pabrik kimia untuk menghasilkan produk-produk berkualitas tinggi sangat diperlukan. Kemampuan bangsa Indonesia dalam hal itu masih belum memadai.
Kegiatan-kegiatan yang sudah banyak dilakukan sendiri oleh Indonesia saat ini adalah tahap 1 (penelitian exploratif/fundamental) yang banyak dilakukan oleh perguruan tinggi dan lembaga penelitian.
Selain itu, kalangan industri dan perusahaan rekayasa sudah melakukan tahapan-tahapan 5, 6, 7, 8, 9 (analisis ekonomi, teknik proyek, teknik konstruksi, teknik operasi, dan teknik penelitian pasar) dengan tahapan sebelumnya umumnya oleh pihak asing.
Jadi yang masih perlu dikembangkan oleh bangsa Indonesia adalah kemampuan melakukan tahapan 2, 3, 4 (penelitian proses, pengembangan proses, dan teknik proses. Tahapan 4 (teknik proses) dapat dikatakan sudah mulai dicoba oleh kalangan industri bekerja sama dengan perguruan tinggi.
IMPORTANCE OF EARLY STAGE-DESICISONS
PROCESS DESIGN STAGES AND TOOLS
Bersambung…
Sekian
Ref: Seider, Seader and Lewin (2004), Chapter 1
THE DESIGN PROCESS
The Design Process
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The Design Process
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Schedule - The Design Process
Primitive Design Problems Example
Steps in Designing and Retrofitting Chemical Processes Assess Primitive Problem Process Creation Development of Base Case Detailed Process Synthesis - Algorithmic Methods Process Controllability Assessment Detailed Design, Sizing, Cost Estimation, Optimization Construction, Start-up and Operation
Environmental Protection Safety Considerations
The Design Process
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Primitive Design Problems
The design or retrofit of chemical processes begins with the desire to produce profitably chemicals that satisfy societal needs that arise in the broad spectrum of industries that employ chemical engineers:
– petrochemicals,
– petroleum products
– industrial gases
– foods
– pharmaceuticals
– polymers
– coatings
– electronic materials
– bio-chemicals
Partly due to the growing awareness of the public, many design projects involve the redesign, or retrofitting, of existing chemical processes to solve environmental problems and to adhere to stricter standards of safety
The Design Process
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Origins of Design Problems
Often, design problems result from the explorations of chemists, biochemists, and engineers in research labs to satisfy the desires of customers to obtain chemicals with improved properties for many applications
However, several well-known products, like Teflon (poly-tetrafluoroethylene), were discovered by accident.
In other cases, an inexpensive source of a raw material(s) becomes available
Other design problems originate when new markets are discovered, especially in developing countries
Yet another source of design projects is the engineer himself, who often has a strong inclination that a new chemical or route to produce an existing chemical can be very profitable.
The Design Process
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A typical primitive problem statement is as follows:
“An opportunity has arisen to satisfy a new demand for VC monomer (VCM), on the order of 800 million pounds per year, in a petrochemical complex on the Gulf Coast, given that an existing plant owned by the company produces one-billion pounds per year of this commodity chemical. Since VCM is an extremely toxic substance, it is recommended that all new facilities be designed carefully
to satisfy governmental health and safety regulations.”
Consider, the need to manufacture vinyl chloride (VC),
C CH Cl
H H
The Design Process
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Assess Primitive Problem
Steps in Process Design and Retrofit
Detailed Process Synthesis -Algorithmic
Methods
Development of Base-case
Plant-wide Controllability Assessment
Detailed Design, Equipment sizing, Cap.
Cost Estimation, Profitability Analysis,
Optimization
The Design Process
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Assess Primitive Problem
Steps in Process Design and Retrofit
Development of Base-case
Detailed Process Synthesis -Algorithmic
Methods
Plant-wide Controllability Assessment
Detailed Design, Equipment sizing, Cap.
Cost Estimation, Profitability Analysis,
Optimization
SECTION A
The Design Process
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Steps in Process Design and Retrofit
The Design Process
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Assess Primitive Problem
Process design begins with a primitive design problem that expresses the current situation and provides an opportunity to satisfy a societal need.
Normally, the primitive problem is examined by a small design team, who begins to assess its possibilities, to refine the problem statement, and to generate more specific problems: Raw materials - available in-house, can be purchased or
need to be manufactured? Scale of the process (based upon a preliminary
assessment of the current production, projected market demand, and current and projected selling prices)
Location for the plant Refined through meetings with engineering technical
management, business and marketing. Brainstorming to generate alternatives
The Design Process
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Example: VC Manufacture
To satisfy the need for an additional 800 MMlb/yr of VCM, the following plausible alternatives might be generated: Alternative 1. A competitor’s plant, which produces 2 MMM
lb/yr of VCM and is located about 100 miles away, might be expanded to produce the required amount, which would be shipped. In this case, the design team projects the purchase price and designs storage facilities.
Alternative 2. Purchase and ship, by pipeline from a nearby plant, chlorine from the electrolysis of NaCl solution. React the chlorine with ethylene to produce the monomer and HCl as a byproduct.
Alternative 3. Since the existing company produces HCl as a byproduct in large quantities are produced, HCl is normally available at low prices. Reactions of HCl with acetylene, or ethylene and oxygen, could produce 1,2-dichloroethane, an
intermediate that can be cracked to produce vinyl chloride.
The Design Process
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Survey Literature Sources
Stanford Research Institute (SRI) Design Reports Encyclopedias
Kirk-Othmer Encyclopedia of Chemical Technology (1991) Ullman’s Encyclopedia of Industrial Chemistry (1988) Encyclopedia of Chemical Processing and Design (McKetta
and Cunningham, 1976) ...
Handbooks and Reference Books Perry’s Chemical Engineers Handbook (1997) CRC Handbook of Chemistry and Physics (1997) ...
Indexes See Ferdowsi Library
Patents (see web for example www.uspto.gov/patft) Internet
The Design Process
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Assess Primitive Problem
Steps in Process Design and Retrofit
Development of Base-case
Plant-wide Controllability Assessment
Detailed Design, Equipment sizing, Cap.
Cost Estimation, Profitability Analysis,
Optimization
Detailed Process Synthesis -Algorithmic
Methods
SECTION B
The Design Process
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Steps in Process Design and Retrofit
The Design Process
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Assess Primitive Problem
Steps in Process Design and Retrofit
Development of Base-case
Detailed Process Synthesis -Algorithmic
Methods
Detailed Design, Equipment sizing, Cap.
Cost Estimation, Profitability Analysis,
Optimization
SECTION C
Plant-wide Controllability Assessment
The Design Process
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Steps in Process Design and Retrofit
The Design Process
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Environmental Issues in Design
Handling of toxic wastes 97% of hazardous waste generation by the chemicals and
nuclear industry is wastewater (1988 data). In process design, it is essential that facilities be included
to remove pollutants from waste-water streams. Reaction pathways to reduce by-product toxicity
As the reaction operations are determined, the toxicity of all of the chemicals, especially those recovered as byproducts, needs to be evaluated.
Pathways involving large quantities of toxic chemicals should be replaced by alternatives, except under unusual circumstances.
Reducing and reusing wastes Environmental concerns place even greater emphasis on
recycling, not only for unreacted chemicals, but for product and by-product chemicals, as well. (i.e., production of segregated wastes - e.g., production of composite materials and polymers).
The Design Process
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Environmental Issues in Design (Cont’d)
Avoiding non-routine events Reduce the likelihood of accidents and spills through the
reduction of transient phenomena, relying on operation at the nominal steady-state, with reliable controllers and fault-detection systems.
Design objectives, constraints and optimization Environmental goals often not well defined because
economic objective functions involve profitability measures, whereas the value of reduced pollution is often not easily quntified economically.
Solutions: mixed objective function (“price of reduced pollution”), or express environmental goal as “soft” or “hard” constraints.
Environmental regulations = constraints
The Design Process
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Safety Considerations
Example Disaster 1 – Flixborough: 1st June 1974 http://www.hse.gov.uk/hid/land/comah/level3/5a591f6.htm
50 tons of cyclohexane were released from Nypro’s KA plant (oxidation of cyclohexane) leading to release of vapor cloud and its detonation. Total loss of plant and death of 28 plant personnel.
Highly reactive system - conversions low, with large inventory in plant. Process involved six, 20 ton stirred-tank reactors.
– Discharge caused by failure of temporary pipe installed to replace cracked reactor.
– The so-called “dog-leg” was not able to contain the operating conditions of the process (10 bar, 150 oC)
The Design Process
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Safety Considerations Flixborough - What can we learn?
Develop processes with low inventory, especially of flashing fluids (“what you don’t have, can’t leak”)
Before modifying process, carry out a systematic search for possible cause of problem.
Carry out HAZOP analysis Construct modifications to same standard as original plant. Use blast-resistant control rooms and buildings
T. Kletz, “Learning from Accidents”, 2nd Ed. (1994)
The Design Process
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Safety Considerations (Cont’d)
Example Disaster 2 – Bhopal: 3rd December 1984 http://www.bhopal.com/chrono.htm
Water leakage into MIC (Methyl isocyanate) storage tank leading to boiling and release of 25 tons of toxic MIC vapor, killing more than 3,800 civilians, and injuring tens of thousands more.
MIC vapor released because the refrigeration system intended to cool the storage tank holding 100 tons of MIC had been shut down, the scrubber was not immediately available, and the flare was not in operation.
Bhopal - What can we learn?– Avoid use of hazardous materials. Minimize stocks of hazardous
materials (“what you don’t have, can’t leak”).– Carry out HAZOP analysis. – Train operators not to ignore unusual readings.– Keep protective equipment in working order.– Control building near major hazards.
The Design Process
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Safety Issues: Fires and Explosions
Compound LFL (%) UFL (%)
Acetylene 2.5 100
Cyclohexane 1.3 8
Ethylene 2.7 36
Gasoline 1.4 7.6
Hydrogen 4.0 75
Flammability Limits of Liquids and Gases LFL and UFL (vol %) in Air at 25 oC and 1 Atm
These limits can be extended for mixtures, and for elevated temperatures and pressures (see Seider et al, 2004).
With this kind of information, the process designer makes sure that flammable mixtures do not exist in the process
during startup, steady-state operation, or shut-down.
The Design Process
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The Design Process - Summary
Steps in Designing and Retrofitting Chemical Processes
Assess Primitive Problem
Process Creation Development of Base Case Detailed Process Synthesis - Algorithmic Methods Process Controllability Assessment Detailed Design, Sizing, Cost Estimation, Optimization Construction, Start-up and Operation
Environmental Protection Environmental regulations design constraints
Safety Considerations Should strive to design for “inherently safe plants”
Assess Primitive Problem - covered today
Process Creation - next week