PLANT DESIGN II (CAB 4023) PRODUCTION OF 396, 000 TONNE OF AMMONIA PER YEAR GROUP 11 MUHAMMAD FAIZ MOHD FUDZAILI 10821 MUHAMMAD FAUZI KHAMIS 10826 MUHAMMAD NUR AZIZI ABDUL AZIZ 10853 NUR IZZATI BOHER @ BUJANG AMRI 10935 SOFIA KEETASOPON 10564 SUPERVISOR: DR MOHANAD EL-HERBAWI

GENERAL OVERVIEW

INTRODUCTION

BACKGROUND STUDY Commercially known as anhydrous ammonia Ammonia is a colourless gas with a sharp, penetrating odour. The heart of ammonia manufacture is the Haber process One of the most essential material of the world nitrogen industry

USAGE OF AMMONIA Household cleansing agent Fertilizer products Manufacture synthetic fibers : nylon and rayon Neutralize acidic by-products of petroleum refining

MARKET STUDY 78% used for fertilizer production. 3% used in direct application 19% consumed for industrial end uses. Continuous growth in the ammonia import correspond to demand for fertilizer production. The additional ammonia availability in the market from low cost capacity will displace local production in other regions where gas costs are higher e.g. Europe and US Source : AFA 15th International Forum

Global ammonia capacity is projected to be 224.1 Mt NH3 in 2014. Global ammonia capacity is projected to increase between 2010 and 2015 at an annual growth rate of 3.5%, equating to a net expansion of 37.4 Mt NH3 over 2009. Global ammonia capacity is projected to be 224.1 Mt NH3 in 2014. Much of the growth in ammonia capacity is associated with new urea capacity. Global urea capacity will expand by a net 30% between 2009 and 2014 corresponds to a compound annual growth rate of 5.4%. International trade of urea and merchant ammonia is projected to expand by 15 and 20%, between 2009 and 2014.

PROBLEM STATEMENT Students are required to: Select the most convenience way to produce ammonia. Calculate the mass balance. Perform heat integration for selected process. Perform study on control and instrumentation. Conduct the economics evaluation. Identify the environmental and safety issues related to the plant.

To design a process plant that produce OBJECTIVE To design a process plant that produce 396, 000 tonnes ammonia per year.

ALTERNATIVE PROCESSES

Synthesis gas production Three process steps of industrial ammonia production: Synthesis gas production Gas purification Synthesis of ammonia

SYNTHESIS GAS PRODUCTION Alternative Processes Steam Reforming Process Partial Oxidation Process Electrolysis Process

Steam Reforming Process Reaction : CH4 + H2O → CO + 3 H2 CO + H2O → CO2 + H2 CH4 + 2 H2O → CO2 + 4 H2 Process Description : Natural gas consists mainly of methane and refinery gas is a mixture of hydrocarbon gases. The resulting gas mixture contains by volume about 57% hydrogen, 21% nitrogen, 10% carbon dioxide 11% carbon monoxide and some impurities. Advantages: Produced more hydrogen if compare to other processes. Less energy requirement. Economically competitive due to the low price of the feedstock. Less carbon monoxide produced.

Partial Oxidation Process Reaction : CnH(2n + 2) + ½ nO2 → nCO + (n + 1)H2 Process Description : Oxygen is used instead of air for the reaction This process is adapted to the partial oxidation of coal and fuel oil The carbonaceous materials are burned with a limited quantity of oxygen in the presence of steam at a temperature of about 1300-1500C Disdvantages: Demands careful control of the feed rates to the combustion chamber. Heat resisting materials are needed for the construction of the reaction vessels bricks. Not economically competitive due to the high price of the oxygen. More carbon monoxide produced. 5. Less hydrogen produced.

Electrolysis Process Reaction : H2O ↔ H2 + O2 Process Description : Two electrodes are placed in a vessel full of water. The cathode is an iron plate and the anode is a nickel iron plate. A diaphragm of asbestos is placed between the electrodes. Advantages: Yields very pure hydrogen Disadvantage : Has been utilized commercially where low-cost electricity is available, such as Canada but high cost of electricity in Malaysia.

SYNTHESIS GAS PRODUCTION CHOOSEN! Steam Reforming Process Partial Oxidation Process Electrolysis Process Produced more hydrogen if compare to other process. Less energy requirement. Economically competitive due to the low price of the feedstock Less carbon monoxide produced.

CO2 REMOVAL Process Advantages Disadvantages Water scrubbing Simple plant No heat load Solvent availability at minimal cost Excessive loss of hydrogen Very high pumping load Poor CO2 removal efficiency CHOOSEN! Amine Rapid absorption Excellent stability Easy regeneration High heat consumption on reactivation Less economical at high concentration of CO2 Hot carbonate Inexpensive absorbent Rapid absorption Reactivation up to 100% Less economical at low CO2 concentrations Usually followed by a second absorber to reach low CO2 concentrations in gas

SYNTHESIS OF AMMONIA CHOOSEN! Designation Pressure, atm Tempera-ture, °C Catalyst Recircu-lation Conversion, % Bleed to remove inert CHOOSEN! Haber-Bosch 200-350 550 Doubly promoted iron Yes 10-30 Claude 900-1000 500-650 Promoted iron No 40-85 Casale 600 500 Promoted iron Yes 15-18 No Fauser 200 500 Promoted iron Yes 12-23 *40 % conversion of the gas upon passage through a single converter and 85 % conversion after passage through a series of converters. Gas is vented after one passes through the converters.

PLANT DESIGN

INPUT-OUTPUT STRUCTURE Recycle Purge Product(NH3) Feed (NG, Air, Steam) Process By-Product (H2O,CO2) Purification of feed stream is not required Purge stream is required Recycle is required (Product & By-Product)

REACTOR DESIGN Flow Pattern Models of Reactor Reactor Type Principal Application Advantages Disadvantages Continuous Stirred Tank Reactor (CSTR) Gas-liquid reaction Consistent product quality due to reproducible process control Low operating costs Wide range of throughput Final conversion lower than in other basic reactor types Unfavorable if the reaction must take place in high pressure Tubular Reactor Homogeneous gas phase reactions Favorable conditions for temperature control by heat supply or heat removal No moving mechanical parts High throughput Very high degree of specialization Relative large pressure drop CHOOSEN!

Reactor Configurations Fluidized-bed Catalytic REACTOR DESIGN Reactor Configurations Fixed-bed Catalytic Reactor Fluidized-bed Catalytic The fixed-bed (packed-bed) reactor is a tubular reactor that is packed with solid catalyst particles. Most designs approximate to plug-flow behavior. In fluidized-bed reactors, solid material in the form of fine particles is held in suspension by the upward flow of the reacting fluid. CHOOSEN!

Fixed-bed Catalytic Reactor REACTOR SELECTION Packed with solid catalyst particles. Highest conversion per weight of catalyst. Behaves as plug flow allows efficient contacting between reactants and catalyst. Flexible Fixed-bed Catalytic Reactor

SEPARATION SYSTEM In general, a series of separations are required after the reaction has taken place. The purposes are follows: - To achieve desired product purity. - To recover unconverted reactants. - To remove the hazardous or undesired components before discharging them to environment.

Heterogeneous mixture To separate water and gas (N2 and H2) SEPARATION SYSTEM Heterogeneous mixture (liquid and gas) Two-phase separator To separate water and gas (N2 and H2) To separate fully converted ammonia product (liquid) and partially converted ammonia product (gas)

MATERIAL BALANCE

HEAT INTEGRATION

What is pinch technology? Objective of pinch analysis Methodology for minimizing energy consumption by optimizing heat recovery systems Objective of pinch analysis To achieve financial saving by constructing the best process heat integration To optimize the process heat recovery and reducing external utility loads

METHODOLOGY Identification of hot, cold and utility streams in the process Thermal data extraction for process and utility streams Selection of initial ∆Tmin value Construction of problem table algorithm Identification Tpinch, QH,min and QC,min via heat cascade table Construction of heat exchanger network Calculation of energy saving

Cold Stream Hot Stream Back

Supply temperature TS(°C) Target temperature TT(°C) Stream Supply temperature TS(°C) Target temperature TT(°C) Utility ∆H (kW) No. Name (Refer to iCON) Name Type 1 E105 H1 Hot 427.22 204.44 32328.6998 2 E103 H2 220.00 40.00 59263.3538 3 E115 H8 460.00 300.00 27361.2603 4 E116 H9 150.00 25379.6722 5 E107 C1 Cold 50.00 290.00 20253.3355 6 E113 C2 30.00 189.61 28841.6240 7 E114 C3 350.00 28715.1726 Back

Ts*= Ts - ∆T/2 Tt*= TT + ∆T/2 NOTE THAT:: Stream Supply temperature TS(°C) Target temperature TT(°C) CP(kW/°C) Shifted temperature (°C) Utility ∆H (kW) ∆Tmin/2 No. Name (Refer to iCON) Name Type TS* TT* 1 E105 H1 Hot 427.22 204.44 145.1149 422.22 199.44 32328.6998 5 2 E103 H2 220.00 40.00 329.2409 215.00 35.00 59263.3538 3 E115 H8 460.00 300.00 171.0079 455.00 295.00 27361.2603 4 E116 H9 150.00 169.1978 145.00 25379.6722 E107 C1 Cold 50.00 290.00 84.3889 55.00 20253.3355 6 E113 C2 30.00 189.61 180.6983 194.61 28841.6240 7 E114 C3 350.00 179.0357 355.00 28715.1726 Ts*= Ts - ∆T/2 Tt*= TT + ∆T/2 NOTE THAT:: 1 CP = ∆H/∆T, ∆H is obtained from iCON 2 ∆Tmin = 10˚C Back

Interval Temperature (˚C) PROBLEM TABLE ALGORITHM Interval Temperature (˚C) Stream Population ∆Tinterval (°C) ∑CPC -∑CPH (kW/°C) ∆Hinterval(kW) Surplus/Deficit 455.00   32.78 -171.0079 -5605.6382 Surplus 422.22 67.22 -316.1228 -21249.7738 355.00 60.00 -137.0871 -8225.2272 295.00 80.00 -50.8882 -4071.0528 215.00 15.56 -380.1290 -5914.8075 199.44 4.83 -235.0141 -1135.1181 194.61 49.61 -378.4663 -18775.7150 145.00 90.00 30.4932 2744.3841 55.00 20.00 -148.5425 -2970.8502 35.00 109 102 110 103 106 104 105 Back

Interval temperature (˚C) Adjusted heat cascade (kW) HEAT CASCADE TABLE Interval temperature (˚C) ∆Hinterval (kW) Heat flow (kW) Adjusted heat cascade (kW) 455.00 0.0000   -5605.6382 422.22 5605.6382 -21249.7738 355.00 26855.4120 -8225.2272 295.00 35080.6392 -4071.0528 215.00 39151.6920 -5914.8075 199.44 45066.4995 -1135.1181 194.61 46201.6176 -18775.7150 145.00 64977.3326 2744.3841 55.00 62232.9485 -2970.8502 35.00 65203.7987 QH,min Tpinch (˚C): 455 + 10/2 = 460˚C QC,min

Combine Composite Curve Grand Composite Curve Back

GRID DIAGRAM

Above pinch region: Cpc > Cph Below pinch region: Cph > Cpc 1 Cp rules: Below pinch region: Cph > Cpc No temperature crossover of hot and cold stream through the heat exchanger 2

GRID DIAGRAM WITH HEAT EXCHANGER DESIGN 1) 28715 kW/2 = 171.0079 kW/˚C x (460˚C - T) 2) T = 376.04˚C Back

COMPARISON ON TOTAL UTILITY CONSUMPTION Total Utility Consumption Before HI Name (Refer to iCON) ∆H (kW) Remaining Heat For Cooling Requirement (kW)   C102 32328.6998 17971.1135 C103 59263.3538 30421.7298 C109 27361.2603 13003.6740 C110 25379.6722 5126.3367 H104 20253.3355 0.0000 H105 28841.6240 H106 28715.1726 Total 222143.1182 66522.8540 Total Utility Consumption After HI

Total Utility Consumption ENERGY SAVING AFTER HEAT INTEGRATION Total Utility Consumption Base Case Design Before HI (kW) 222143.1182 After HI 66522.8540 Energy Saved 155620.2642 % Reduction 70.05% = (222,143.1182 kW – 65,522.8540 kW) / 155620.2642 kW = 70.05%

PLANT LAYOUT

PLANT LAYOUT

PROCESS FLOWSHEETING

INSTRUMENTATION & CONTROL

SAFETY & LOSS PREVENTION

HAZARD AND OPERABILITY STUDY (HAZOP) Objective of HAZOP To indentify potential hazards and potential operability problems that may arise from the deviations of design intent.

LIST OF HAZOP GUIDE WORDS NO None of design intent is achieved. MORE Quantitative increase LESS Quantitative decrease REVERSE The logical opposite of the intention AS WELL AS An additional activity occur PART OF Only some of design intent is achieved OTHER THAN Complete substitution

HAZOP ANALYSIS HAZOP Study Nodes Node 1 Methanator (R105) including incoming line discharge from heat exchanger (E117) Node 2 Ammonia Converter (R106) including incoming line discharge from heat exchanger (E105) Node 3 Ammonia Separator (V106) including incoming line discharge from cooler (E120)

Node 1

HAZOP ANALYSIS: NODE 1 Parameter : Flow Guide Word Deviation Possible Causes Consequences Safeguards Recommendations NO No Flow 1. Line (S22) leakage. 2. Loss of feed supply. 3. Blockage inside pipeline (S22). 1. No process gas into the reactor 2. Release of toxic material. 1. Flow indicator is provided. 2. Perform regular schedule inspection on process line. 1. Install gas detection system is provided. 2. Install No Flow alarm

Parameter : Flow Guide Word Deviation Possible Causes Consequences Safeguards Recommendations LESS Less Flow 1. Partially plug line. 2. Control valve failure. 3. Line (S22) leakage. 1. Pressure drop inside the reactor (R105) 2. Less process gas into reactor. 1. Flow indicator is provided. 2. Perform regular schedule inspection on process line. 1. Install gas detection system is provided.

Parameter : Flow Guide Word Deviation Possible Causes Consequences Safeguards Recommendations MORE More Flow 1. Control valve failure. 1. Over pressure inside the reactor. 2. May lead to reactor explosion 3. Undesired product quality 1. Flow indicator is provided. 2. Perform regular schedule inspection on process line. 1. Install gas detection system is provided. 2. Install high flow alarm. REVERSE Reverse Flow 1. Back pressure. 2. Failure of pressure controller. 3. Compressor trips. 1. Reverse flow from reactor (R105) 2. Less of product yield. 1. Flow indicator is provided. 2. regular schedule inspection on process line. 1. Install Non-return/check valve

Parameter : Temperature Guide Word Deviation Possible Causes Consequences Safeguards Recommendations LOW Low Temperature 1. Malfunction of heat exchanger (E117) 1. Rate of reaction is reduced. 1. Temperature indicator is provided. 1. Install low temperature alarm. HIGH High Temperature 1. Failure of cooler. 2. Poor heat transfer in the cooler. 3. HE (E117) failure. 1. Less of product goes to the storage. 1. Temperature indicator is provided. 2. High temperature alarm is provided. 1. Install high temperature alarm.

Parameter : Pressure Guide Word Deviation Possible Causes Consequences Safeguards Recommendations LOW Low Pressure 1. Compressor failure. 2. Pipe leakage. 1. Impact to reactor. 2. May lead to reverse flow. 1. Pressure indicator is provided to notify operator. 1. Install high temperature alarm. 2. Install Low pressure alarm. HIGH High Pressure 1. Failure of pressure relief valve. 2. More process gas into the reactor. 3. Pipe blockage. 1. Pipe vibration. 2. May lead to explosion. 1. Pressure indicator is provided to notify operator. 1. Install high pressure alarm. 2. Install emergency shutdown system.

WASTE TREATMENT

Generally, the effluent discharge from Ammonia Plant needs to comply with Environmental Quality (Sewage and Industrial Effluents) Regulations, (Regulation 8(1) Third Schedule, Standard A, EQA 1979). The main consideration in wastewater treatment system is the COD and BOD value. Parameter Unit Standard A B Temperature °C 40 pH Value - 6.0 – 9.0 5.5 – 9.0 BOD at 20°C mg/L 20 50 COD 100 Oil and Grease Not detectable 10.0

WASTE STREAM Stream No. Component Composition Flow rate (kg/hour) Phase W6 Hydrogen 0.00008% 0.04 Liquid Nitrogen 0.00558% 2.89 Carbon dioxide 0.33557% 173.78 Water 99.65878% 51610.48 54 17.34567% 2087.35 Gas 78.74078% 9475.54 Methane 2.44785% 294.57 Ammonia 1.46570% 176.38

WASTEWATER STREAM

WASTEWATER STREAM

WASTEWATER TREATMENT SYSTEM

PROCESS ECONOMICS & COST ESTIMATION

PLANT SITE SELECTION 1 (selected) 2 Selected Site Gebeng Industrial Estate Phase IV Pasir Gudang Industrial Estate Kerteh Petrochemical Integrated Complex Types of Industrial 5 Price and Land Areas 4 3 Raw Material Sources Transportation Utilities TOTAL MARKS 23/25 21/25 22/25 PERCENTAGES (%) 88 76 80 RANKING 1 (selected) 2 CHOOSEN!

COMPARISON ON PLANT SITE LOCATION

GEBENG INDUSTRIAL ESTATE

ECONOMICS EVALUATION Total Capital Investment: = Fixed Capital Investment + Working capital + Land Cost = RM 379,071,028.14 + RM 18,953,551.41 + RM 6,151,254.01 = RM 404,175,833.56 ≈ RM 404 million Total Cost of Production/Total Operating Cost: = Fixed Cost + Variable Charges + General Expenses = RM 71,415,500.21 + RM 180,306,114.35 + RM 7,581,420.56 ≈ RM 259,303,035.12

PROFITABILITY ANALYSIS UNDISCOUNTED CASH FLOW ANALYSIS From Cumulative cash flow diagram for undiscounted rate above: The rate of return is 26.51% Payback time is 3.3 years after plant start-up

DISCOUNTED CASH FLOW DIAGRAM From the discounted cash flow diagram above: At minimum discount rate of 15%, the net present value is RM550 million with payback time of 3.5 years The discounted cash flow rate of return is 74.95%

From the economic analysis done, the plant is estimated to have a capital investment of RM 215 million. At discount rate of 15%, the net present value of 550 million is attainable for a project life of 20 years and payback time of 3.5 years. With DCFRR of 74.95% and rate of return of 41.33% which is larger than the minimum attractive rate of return of 15%, the project is economically attractive and feasible.

CONCLUSION