Optimisation of Palm Oil Milling Processes

Transcription

1 A Systematic Approach for the Synthesis and Optimisation of Palm Milling Processes Steve Z. Y. Foong, Yi Ling Lam, Viknesh Andiappan, Dominic C. Y. Foo, and Denny K. S. Ng, Department of Chemical and Environmental Engineering/Centre of Sustainable Palm Research (CESPOR), The University of Nottingham Malaysia Campus, Broga Road, Semenyih 43500, Malaysia School of Engineering and Physical Sciences, Heriot-Watt University Malaysia, Putraaya, Wilayah Persekutuan Putraaya, Malaysia SUPPORTING DOCUMENT SHEET MATHEMATICAL MODEL FORMULATION The following subsections present a set of formulation based on the generic superstructure of a palm oil milling process given in Figure 2 (refer to the manuscript). It is assumed that the feedstock i supplied was constant in this set of formulation. A detailed formulation for the proposed multiperiod optimisation model is presented in the full manuscript with comprehensive descriptions on each equation derived. Material Balance Equation S1 shows the component balance for i which may be sent to potential technology. Oi is calculated via eq S2. 1

2 F i Oi = 1 i B F i (S1) i i = F OP i (S2) converts i into p with conversion Xip and the total production rate of p is given in eq S3. F p = I i1 1 B F X i ip p (S3) Similarly, p can be distributed to potential technology to produce p as shown in eq S4 ' F = B F p (S4) p ' 1 ' in which p is converted p with conversion Xp p via technology. The total production rate of p is given in eq S5. P ' = ' F X p1 ' 1 F B p (S5) Equations S6 and S7 calculates the Op and Op from Lip, Lp p, Rip and Rp p. O p = O i I B F L B F R p (S6) i1 1 i ip I i1 1 i ip O P ' P ' = Op B ' F L B ' F R p1 ' 1 p1 ' 1 p (S7) The OPp and OPp are then calculated using eqs S8 and S9. Op OP p = 100% p (S8) F p O OP = 100% p (S9) F 2

3 Despite there are only two stages of conversion technologies and are presented, the formulation can be expanded to match the case study. Utility Balance The u consumption, S11. Con F u and electricity e consumption, Con Ee can be calculated with eqs S10 and F Con u I P ' = B FiUup B ' F Uu' i1 1 p1 ' 1 p (S10) P 1 p1 ' P' ' 1 1 Con E = B F Y B F Y z Y z Y p (S11) e i ep e' 1 Equations S12 and 13 determines the equipment units needed, z and z are determined based on Design F and Design F '. e ' ' 1 ' e' P Design z F B F (S12) p1 P' 1 p Design z B F (S13) ' F ' ' ' es in transmission and distribution accounting for additional 20% of u and e demand as shown in eqs S14 and S15. Demand Con F u F u (S14) 1.2 u Demand E e 1.2 E e Con (S15) Economic Analysis The EP is evaluated from GP, CRF and CAPEX using eq S16 EP = GP - CRF CAPEX (S16) 3

4 where GP and CRF are determined via eqs S17 and S18 respectively. P' I U E Demand Demand GP AOT Fp ' C Fi Ci Fu Cu Ee Ce OPEX 1 i1 u1 e1 CRF r (1 r) max k max k t (1r) 1 t p, i, u k ε, (S17) (S18) Meanwhile, CAPEX and OPEX are calculated based on z and z as shown in eqs S19 and S20. CAPEX z CC z CC ' ' 1 ' 1 ' (S19) OPEX z OC z OC ' ' 1 ' 1 ' (S20) Additional Constraints Addition constraints (eqs. S21 to S24) are added to ensure a single type of technology and were selected. B 0,1 (S21) 1 B 1 (S22) B ' 0,1 (S23) ' ' 1 B 1 (S24) ' where B and B are binary variable denoting the existence of technology and respectively. 4

5 CASE STUDY Palm oil mill effluent (POME) Low Pressure Steam Fresh Fruit Bunches (FFB) Low Pressure Horizontal Vertical Tilted Empty fruit bunches (EFB) Pressed empty fruit bunch (PEFB) EFB Screw Press Recovered Water Vertical Clarifier Vacuum Clarifier Recovered Two-Phase Three-Phase Palm oil mill effluent (POME) cake (DC) Medium Pressure Steam Crusher + Continuous High Pressure Horizontal Sterilized Fruit Bunches Rotating Thresher Sterilized fruitlet Low Pressure Steam Steam Inection Digester Digested fruitlet Liquid product Screw Press Double Press Aqueous phase Three-Phase Organic phase Centrifugal Purifier Palm oil mill effluent (POME) Clarified oil Vacuum Dryer Crude palm oil (CPO) Water Solid product Cake (DC) Palm kernel (PK) Silo Dryer Palm kernel shell (PKS) Wet kernel Clay Bath Hydrocyclone Modified Hydrocyclone Cracked nut Air Cyclone Four-Stage Winnowing Column Cracked mixture Cracked mixture Nut Cracker Double Cracker Ripple Mill Rolek Nut Cracker Palm nut Depricarper Horizontal Rotating Drum Separator Palm oil mill effluent (POME) Palm pressed fibre (PPF) Palm kernel shell (PKS) Palm kernel (PK) Palm pressed fibre (PPF) Figure S1. Superstructure for palm oil milling processes. 5

6 Table S1. Technologies Costing and Conversion Data Sterilisation Horizontal Low-Pressure Horizontal High-Pressure Vertical Tilted Crusher + Continuous Threshing Rotating Drum Digestion Steam Inection Digester Pressing Screw Press 1,000,000 Operating cost 200, t fresh fruit Electricity 30 kwh - Low pressure steam 0.25 t/t FFB 0.15 t steam lost Fresh fruit bunch 1 t 0.87 t sterilized fruit bunch 0.23 t POME 800,000 Operating cost 160, t fresh fruit Electricity 17 kwh - Medium pressure steam 0.2 t/t FFB 0.11 t steam lost Fresh fruit bunch 1 t 0.90 t sterilized fruit bunch 0.19 t POME 1,000,000 Operating cost 120, t fresh fruit Electricity 40 kwh - Low pressure steam t/t FFB t steam lost Fresh fruit bunch 1 t 0.87 t sterilized fruit bunch 0.23 t POME 1,200,000 Operating cost 180, t fresh fruit Electricity 75.4 kwh - Low pressure steam 0.25 t/t FFB 0.14 t steam lost Fresh fruit bunch 1 t 0.90 t sterilized fruit bunch 0.23 t POME 1,050,000 Operating cost 157, t fresh fruit Electricity 90 kwh - Low pressure steam 0.36 t/t FFB 0.18 t steam lost Fresh fruit bunch 1 t 0.88 t sterilized fruit bunch 0.30 t POME 225,000 Operating cost 33, t sterilized fruit Electricity 28 kwh - Sterilized fruit bunch 1 t 0.76 t sterilized fruitlet 0.24 t empty fruit bunch 150,000 Operating cost 15, t sterilized fruitlet Electricity 18 kwh - Low pressure steam 0.13 t/t FFB 0.09 t steam lost Sterilized fruitlet 1 t 1.04 t digested fruitlet 100,000 Operating cost 20, t digested fruitlet Electricity 25 kwh - Digested fruitlet 1 t 0.58 t pressed liquid 0.42 t pressed cake 3.0% - [1] 2.0% [2] 4.0% [1] 2.5% [3] 3.0% [4] 4.0% % - [5] [1] [6] 6

7 Double Pressing Nut Separation Depericarper Rotating Drum Separator Nut Cracking Nut Cracker Double Cracker Ripple Mill Rolek Nut Cracker Kernel Separation Air Cyclone Four-Stage Winnowing Column Clay Bath Hydrocyclone 180,000 Operating cost 36, t digested fruitlet Electricity 40 kwh - Digested fruitlet 1 t 0.60 t pressed liquid 0.40 t pressed cake 250,000 Operating cost 25, t pressed cake Electricity 68.6 kwh - Press cake 1 t 0.59 t palm fruit nut 0.41 t palm pressed fibre 200,000 Operating cost 30, t pressed cake Electricity 55.2 kwh - Press cake 1 t 0.58 t palm fruit nut 0.42 t palm pressed fibre 130,000 Operating cost 26,000-8 t palm fruit nut Electricity 26.4 kwh - Palm fruit nut 1 t 0.95 t cracked mixture 0.05 t uncracked nut 175,000 Operating cost 34,000-8 t palm fruit nut Electricity 35.3 kwh - Palm fruit nut 1 t 0.98 t cracked mixture 0.02 t uncracked nut 180,000 Operating cost 36, t palm fruit nut Electricity 31.1 kwh - Palm fruit nut 1 t 0.99 t cracked mixture 0.01 t uncracked nut 70,000 Operating cost 10,000-8 t cracked mixture Electricity 18.6 kwh - Cracked mixture 1 t 0.81 t cracked nut 0.19 t palm pressed fibre 250,000 Operating cost 13, t cracked mixture Electricity 29.2 kwh - Cracked mixture 1 t 0.19 t palm pressed fibre t palm kernel shell palm kernel 35,000 Operating cost 3,500-5 t Electricity 40.2 kw - Water 1.8 t/t cracked nut 1.8 t POME Cracked mixture 1 t t wet kernel t palm kernel shell 40,000 Operating cost 4,000-5 t cracked mixture Electricity 37.5 kwh - Water 1.7 t/t cracked nut 1.7 t POME Cracked mixture 1 t t wet kernel t palm kernel shell 3.0% - [7], [8] - - [9] [10] [11] [12] [13] - - [14] - - [15], [16] - - [14] - - [11] 7

8 Modified Hydrocyclone Kernel Drying Silo Dryer Clarification Two-Phase Three-Phase Vertical Clarifier Vacuum Clarifier Purification Centrifuge Purifier + Vacuum Purifier Recovery Three-Phase EFB Screw Press 50,000 Operating cost 5,000-5 t cracked mixture Electricity 30.5 kwh - Water 1.7 t/t cracked nut 1.5 t POME Cracked mixture 1 t t wet kernel t palm kernel shell 50,000 Operating cost 5,000-5 t wet kernel Electricity 37.1 kw - Wet kernel 1 t 0.95 t palm kernel 230,000 Operating cost 28, t pressed liquid Electricity 45 kwh - Pressed liquid 1 t 0.61 t organic phase 0.39 t POME 300,000 Operating cost 35, t pressed liquid Electricity 50 kwh - Pressed liquid 1 t 0.58 t organic phase 0.33 t POME 0.09 t decanter cake 150,000 Operating cost 15, t pressed liquid Electricity 32 kwh - Water Pressed liquid t/t pressed liquid 1 t 0.54 t organic phase t aqueous phase 265,000 Operating cost 27, t pressed liquid Electricity 43 kwh - Water t/t pressed liquid 0.52 t organic phase Pressed liquid 1 t t aqueous phase 390,000 Operating cost 55, t organic phase Electricity 35 kwh - Organic phase 1 t t crude oil t POME 300,000 Operating cost 35, t aqueous phase Electricity 50 kwh - Aqueous phase 1 t 0.02 t recovered oil t POME t decanter cake 120,000 Operating cost 20, t empty fruit Electricity 15 kwh - Empty fruit bunch 1 t t recovered oil t pressed EFB % - [17], [18] 3.0% - [19] 5.0% - [20] 3.5% % - 60% [21] 8

9 Note: 1. Capital and operating costs for each technology are estimated based on current supplier availability. 2. Only maintenance costs were included in the operating cost calculation. Labour costs were not being considered in the model. 3. The authors declare no competing financial interest Industrial information obtained from Havy s Mill RESULTS Table S2. Economic Parameters for Scenario 1 Economic Analysis Unit Optimal Conventional configuration configuration Difference (%) Capital cost, CAPEX million USD Operating cost, OPEX million USD/y Gross Profit, GP million USD/y Economic Performance, EP million USD/y Benefit-cost ratio, BCR Table S3. Products, By-products and Utilities for Scenario 1 Flowrates Difference Materials Unit Optimal Conventional configuration configuration % Products Crude palm oil, CPO t/h Palm kernel, PK t/h By-products Palm oil mill effluent, POME t/h Palm kernel shell, PKS t/h cake, DC t/h Palm pressed fibre, PPF t/h Empty fruit bunch, EFB t/h Pressed empty fruit bunch, PEFB t/h Utilities demand Water m 3 /h Low pressure steam, LPS t/h Electricity kwh Others Total oil lost, L t/h Percentage of oil lost %

10 Table S4. Content in By-products for Scenario 1 Materials Unit Content Difference Optimal Conventional (%) configuration configuration Palm oil mill effluent, POME t/h cake, DC t/h Palm pressed fibre, PPF t/h Empty fruit bunch, EFB t/h Pressed empty fruit bunch, PEFB t/h Table S5. Economic Parameters for Scenario 2 Season, α s Unit Low Medium High Average Capital cost, CAPEX million USD Operating cost, OPEX million USD/y Gross Profit, GP million USD/y Economic Performance, EP million USD/y Table S6. Product, By-product and Utility for Scenario 2 Materials Unit Flowrates Low Season Medium Season High Season Feedstock Fresh fruit bunch, FFB t/h Products Crude palm oil, CPO t/h Palm kernel, PK t/h By-products Palm oil mill effluent, POME t/h Palm kernel shell, PKS t/h cake, DC t/h Palm pressed fibre, PPF t/h Pressed empty fruit bunch, PEFB t/h Utilities consumption Utility water m 3 /h Low pressure steam, LPS t/h Electricity kwh ,300 Others Total oil lost, L t/h Percentage of oil lost %

11 Table S7. Chosen and Operated Technologies for Scenario 2 selected Design Capacity Low Medium High Season Season Season Tilted 20,000 kg fresh fruit bunch Rotating Drum 40,000 kg sterilized fruit bunch Steam Inection Digester 20,000 kg sterilized fruitlet EFB Screw Press 10,000 kg empty fruit bunch Double Screw Press 25,000 kg digested fruitlet Depericarper 10,000 kg pressed cake Rolek Nut Cracker 10,000 kg palm fruit nut Four-Stage Winnowing Column 15,000 kg cracked mixture Vertical Clarifier 10,000 kg pressed liquid Centrifuge Purifier 10,000 kg organic phase Three-Phase 20,000 kg aqueous phase Total Unit Table S8. Economic Parameters under for Scenario 3 Market demand price Unit High Demand Low Demand Capital cost, CAPEX million USD Operating cost, OPEX million USD/yr 1.21 Gross Profit, GP million USD/yr Economic Performance, EP million USD/yr Payback Period, PP yr REFERENCES [1] Poku, K. Small-Scale Palm Processing in Africa; Food and Agriculture Organization of the United Nations, [2] Noerhidaat; Yunus, R.; Zurina, Z. A.; Syafiie, S.; Ramanaidu, V.; Rashid, U. Effect of High Pressurized Sterilization on Palm Fruit Digestion Operation. Int. Food Res , 23 (1), [3] Loh, T. K. Tilting. Palm Eng. Bull. 2010, 94, [4] Kandiah, S.; Basiron, Y.; Suki, A.; Taha, R. M.; Tan, Y. H. Continuous Sterilization: The New Paradigm for Modernizing Palm Milling.. Palm Res. 2006, [5] Department of Industrial Works, Environmental Management Guideline for the Palm Industry; Environmental Advisory Assistance for Industry, [6] Palm Research Institute of Malaysia (PORIM). Extraction. Palm Factory 11

12 Process Handbook, Part 1: General Description of The Palm Milling Process; Shah Alam, 1985; pp [7] Harun, M. Y.; Che Yunus, M. A.; Morad, N. A.; Ismail, M. H. S. An Industry Survey of the Screw Press System in Palm Mills: Operational Data and Malfunction Issues. Eng. Failure Anal. 2015, 54, [8] Palm Mill Consultants and Training. Press Station Operations ndex.php/processingknowledge/10-press-station-operations (accessed Apr 10, 2017). [9] HUATAI Cereals and s Machinery. Palm Kernel Recovery Station machine.com/palm_kernel_recovery_station_62.html. (accessed Apr 11, 2017). [10] Obincowelds Construction Company Ltd. Palm Nut Fibre Separator weldconst.blogspot.my/2015/05/palm-fruit-fibre-separator.html. (accessed Apr 11, 2017). [11] Hartley, C. W. S. The Palm (Elaeis guineensis acq.), 3rd ed.; Longman Scientific & Technical: Harlow, Essex, England, [12] Maycock,. H. Innovations in Palm Mill Processing and Refining, Palm Research Institute of Malaysia, [13] Rohaya, M. H.; Nasrin, A. B.; Choo, Y. M.; Ma, A. N.; Ravi, N.; A Commercial Scale Implementation of Rolek TM Palm Nut Cracker: Techno-Economic Viability Study for Production of Shell-Free Kernel.. Palm Res. 2006, 18, [14] Iezany, M. R.; Enhancing the Efficiency Process for Separation of Dry Shell and Palm Kernel, Fac. Chem. Nat. Resour. Eng. Univ. Malaysia Pahang, [15] Rohaya, M. H.; Nasrin, A. B.; Mohd Basri, W.; Choo, Y. M.; Ridzuan, R.; Ma, A. N.; Ravi, N. M. Chemistry, Processing and Bio Energy Palm. In Proceedings of the Malaysian Palm Board (MPOB) International Palm Congress; Malaysian Palm Board: Kuala Lumpur, Malaysia, 2009; pp 9 12 [16] Rohaya, M. H.; Ridzuan, R.; Che Rahmat, C. M.; Choo, Y. M.; Nasrin, A. B.; Nu man, A. H. Dry Separation of Palm Kernel and Palm Shell Using a Novel Five-Stage Winnowing Column System. Technologies 2016, 4, 13 [17] Singh, G.; Manoharan, S.; Kanapathy, K.; Commercial Scale Bunch Mulching of Palms [Malaysia], Proc. Int. Conf. Palm Agric. Eighties, Kuala Lumpur, 1982; pp [18] orgensen, H. K.; Singh, G. An Introduction of The - Drier System in The Clarification Station for Crude and Sludge Treatment. Semin. Malaysian Dep. Environ [19] Alfa Laval. PANX s for Crude Palm : High Performance Three-Phase s PANX/ (accessed Apr 3, 2017). [20] Dexter, Z. D; oseph, C. G.; Zahrim, A. Y.; A Review on Palm Mill Biogas Plant Wastewater Treatment Using Coagulation-Ozonation, in International Conference on Chemical Engineering and Bioprocess Engineering, 2016, 36, pp [21] Malaysian Palm Board (MPOB). Production of Strand Fibre From Empty Fruit Bunch (EFB) (accessed: Apr 10, 2017). 12

13 AUTHOR INFORMATION Corresponding author (D.K.S.N.). Telephone: +6 (03) Fax: +6 (03) Other authors s: (S.Z.Y.F.); (Y.L.L.); (V.A.); (D.C.Y.F.). 13