Water Conservation_RM Mathur

March 16, 2018 | Author: ekbo63 | Category: Pulp (Paper), Paper, Recycling, Mathematical Optimization, Industries


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Water Conservation In Pulp & Paper Industry Through Innovative Water Management & Modeling Techniques. R. M. Mathur, B.P. Thapliyal, A.K.Goel   Central Pulp And Paper Research Institute P.O.Box. 174, Saharanpur Central Pulp & Paper Research Institute , Saharanpur •Pulp and paper industry is one of the major water  consuming industries.  •Water is used for a variety of processes and gets  contaminated  during  processing  with  raw  materials,chemicals, by-products & residues.  •Treatment  of  contaminated  wastewater  has  always  been  an  expensive  &  technically  challenging subject.  Central Pulp & Paper Research Institute , Saharanpur Water Consumption In Indian Paper Mills Raw Material Bamboo Wood+Bamboo Wood+Bamboo Wood+Bamboo+RCF Agro Residues RCF Market Pulp Products Writing/Printing Paper Writing/Printing Paper Writing/Printing Paper  Unbleached varieties News print Writing/Printing Paper News print/ writing  Printing Speciality Paper Water Consumption m3/t 100-120 90-125 80-120 95 100 35 90 Central Pulp & Paper Research Institute , Saharanpur Typical Water Consumption in Wood/ Bamboo Based Mill Others  11% Bleaching  30% Stock  Preparation 4% Power House 6% Chemical  Recovery 10% Pulping  14% Paper  Machine 25% Central Pulp & Paper Research Institute . Saharanpur .   •  recycle and  •  regeneration opportunities. Saharanpur .  Central Pulp & Paper Research Institute .Water management techniques can prove to  be highly effective as they enable efficient  usage of water with considerations of  •  reuse. Central Pulp & Paper Research Institute . Saharanpur .Process Integration The  application  of  methodologies  aimed  at  designing/modernizing    an  Industrial  Facility  by  optimizing  its  various  constituent  units  rather  than improving each individual unit by itself. Saharanpur .Process Integration Methods •Classical pinch based •Mathematical programming based Central Pulp & Paper Research Institute .   Central Pulp & Paper Research Institute .  •Water  surplus  diagrams  are    utilized  to  target water requirement. Saharanpur .Pinch Based Approach •Graphical technique to minimize fresh water  flow •An  extension  of  the  pinch  analysis  technique for heat integration. Purity Fresh Water Water Sources Concentration Water Demands Water Pinch Waste water •Not suitable for multiple contaminant systems Central Pulp & Paper Research Institute . Saharanpur Water Flow .Water Pinch – Composite Curves •Each water related process operation considered as having water inputs and output streams and composite of water demand (Input) and water sources (Output) can be constructed.   •A system of equations is solved with constraints to  get values for various water streams.Mathematical Programming Approach •The  pinch  point  (  pinch  concentration  and  pinch  mass  load)  is  calculated  by  application  of  Composite Table Algorithm (CTA).  •A  Network  is  generated  by  applying  Nearest  Neighbor Algorithm (NNA) •Network  of  all  possible  matches  is  created  and    the system is optimized for minimum fresh water  requirement  based  on  capital/operating  expenses.  Central Pulp & Paper Research Institute . Saharanpur .  reuse & regeneration.  •Provides  insight  into  water  targeting  with  a  consideration of recycle.  Central Pulp & Paper Research Institute . Saharanpur .Advantages of Mathematical Programming Approach •Provides a robust way of water network design. Saharanpur .  •This  demand  may  be  fulfilled  by  mixing  fresh  water  with  effluent  streams  from  other  water  using  operations  and  regenerated water. •The  process  outlet  streams  may  be  used  to  satisfy  the  demand  of  other  operations. Central Pulp & Paper Research Institute .  sent    to  treatment  units  or  discharged without treatment.  •Each  water  using  operation  demands  a  certain  quality  and quantity of water to satisfy its process needs.Basic Network Structure •A  basic  integrated  water  network  consists  of  a  set  of  water using and water treating operations. Unit operation mass flow C P in C Water out C P out Process C Water in C P in Concetration C W out C P out C W  in m. Mass flow rate Central Pulp & Paper Research Institute . Saharanpur . Saharanpur .Water limiting profile Process 4 800 Concetration Limiting Profile  curve Process 3 400 Water Supply  Line 100 Process 1& 2 m. Mass flow rate Central Pulp & Paper Research Institute . Mass flow rate m. Printing and writing papers •Raw materials .000 tpa •Products .hardwood and bamboo .CASE STUDY Mill Details:•Production 75. ratio(84:16) •6 paper machines •3 stationary batch digesters •Pulp is bleached by using C/DEopD1D2 bleaching sequence. • Central Pulp & Paper Research Institute . Saharanpur .   Central Pulp & Paper Research Institute .  •A  complete  water  balance  of  the  pulp  mills  was  prepared using online & portable flow meters.  •The  water  samples  from  various  streams  were  characterized with respect to their pollution load. Saharanpur .METHODOLOGY •The  study  was  carried  out  for  two  contaminants  (TS  &  COD)  in  the  bleach  plant  for  reuse  &  recycle options. Saharanpur .Water Balance Flow Diagram for Mill ( All Figures in m3/hr) Central Pulp & Paper Research Institute .   The  limiting  contaminant  levels  are  fixed  at  10  %  above the current values. •Restriction on re use of water streams •All  matches  prohibited  by  pH  are  disallowed.Data Extraction: •All  operations  assumed  to  be  fixed  contaminant  (FC)  and  fixed  flowrate  operations  type. Saharanpur . •Order  and  flowrate  from  one  process  to another is maintained • Central Pulp & Paper Research Institute . Saharanpur . Extracted Flow Diagram Central Pulp & Paper Research Institute .368 D1 1854 403 CD Pulp washing EOP Pulp washing 368 2970 403 2081 367 1910 373 1447 847 656 S1 D2 D3 1190 367 1037 373 S2 S3 D1 Pulp washing D4 990 847 D2 Pulp washing S4 D5 656 Decker Pulp washing S5 Fig. Saharanpur .No  Detail of Streams  Fin Cin max   m3/hr  TS COD ppm  ppm  4457 3827 3683 3134 2617 1854 1190 1037 990 656 Fout m3/hr  63 51 57 63 63 Cin m ax   COD ppm  2970 2081 1910 1447 656 TS ppm  8797 6982 5674 5063 2617 1 2 3 4 5 C/D Washer 368 EOP Washer 403 D1 Washer D2 Washer Decker washer 367 373 847 Central Pulp & Paper Research Institute .Flow rate and Contamination Data for Mill S. 1 423.4 65.6 149. Net Flow..2 293.7 326. C . Cmin Concentration. Flow ppm t/hr 600 0 d 847 656 847 s 847 Load Kg/hr 0 47.4 47. FlowSource  Flow x ( C2 – C1)/1000 Cumulative Load.5 471.1 980.0 d d d s d s s s 373 367 403 373 368 367 403 368 990 1037 1190 1447 1854 1910 2081 2970 3000 0 373 740 1143 770 1138 771 368 0 Pinch conc.9 1308.4 436.0 Slope 0 72.9 62. Central Pulp & Paper Research Institute .5 113.2 0..8 327.9 785.0 17.0 178. kg/hr (m) 0 47.0 ……….3 47.0 1308.8 313..3 849.4 0.4 63.m…….6 444.2 471.4 440. Saharanpur Pinch Load Pinch point .7 131.Composite Table Algorithm  Flow =  FlowDemand . kg/hr Central Pulp & Paper Research Institute .Limiting Composite Curve Limiting Composite Curve Contaminant Concentration. Saharanpur . ppm 3000 2500 2000 1500 1000 500 Water Composite curve Pinch Concentration Pinch Line Pinch Load 0 250 500 750 1000 1250 1500 Contaminant Load.  than whatever is available of that  source is used completely & next neighbor  is considered to satisfy the demand. Saharanpur .Nearest Neighbour Algorithm ØSources which are immediate higher/ lower  in concentration for a demand are mixed in  ratio  determined  by  mass  balance  to  satisfy the demand. Central Pulp & Paper Research Institute . ØIf the required flow rate is not available for  a source.  DP  + FS (K+1). Saharanpur . Central Pulp & Paper Research Institute .DP  CS(K+1)  =FDP  CDP Where F&C are flowrate & concentration SK & S(K+1)  are immediate cleaner& dirtier  sources ( Nearest Neighbour)  DP is the particular demand. Dp  CSK  +FS (K+1).  DP  = FDP FSK .Nearest Neighbour Algorithm The mass balance equations areFSK . 0 63 Used  191.0 0.0 51.0 0.0 179.W.0 0.0 0.0 125.0 47.0 0. Saharanpur .0 63.0 179.0 784.0 76.0 76.0 305.0 EOP Washer D1 Washer D2 Washer Decker Washer D4 {373}  D5 {847}  76.0 0.0 66.0 57.0 6.0 37.0 275.0 63.0 47.0 708.0 235.0 0.Fresh water Network before study No.0 63.0 51.0 63.0 0.0 0.0 306.0 51.0 63.0 Extra  D2 {403}  D3 {367}  50.0 40.0 C/D Washer D1 {368}  65.0 37. B/W C/D Washer o/l EOP Washer o/l D1 Washer o/l D2 Washer o/l Decker Washer o/l F (m3/hr)  Available  191 37 47 304 351 311 310 784 63.0 250.0 55.0 4.0 57.0 63.  Streams  Name  S1 S2 S3 S4 S5 S6 S7 S8 P1 P2 P3 P4 P5 Freshwater B/W from PM 4 Feed from BSW C/D Washer B/W EOP Washer B/W D1 Washer B/W D2 Washer B/W D.0 57.0 Central Pulp & Paper Research Institute .0 240. Saharanpur .0 234.5 290.0 67.0 √ 50.0 0.0 47.0√ 37.0 305.0 5.0 30.0 716.0 47.0 21.0 21.0 Central Pulp & Paper Research Institute .0 51.0 310.  Streams  Name  S1 S2 S3 S4 S5 S6 S7 S8 P1 P2 P3 P4 P5 Freshwater B/W from PM 4 Feed from BSW C/D Washer B/W EOP Washer B/W D1 Washer B/W D2 Washer B/W D.0 63.0 37.0 63.0 290.0 784.0 √ 0.0 0.0 0.0 0.0 C/D Washer D1 {368}  70.0 √ 0.5 63.0 63.0 57.0 63.0 17.0 Extra  D2 {403}  D3 {367}  30.0 234.Fresh Water Network After Study No.W.5 30.0 √ 21.0 242.0 57.0 11.0 70.0 √ 0.0 √ 0.5 EOP Washer D1 Washer D2 Washer Decker Washer D4 {373}  D5 {847}  70.0 0. B/W C/D Washer o/l EOP Washer o/l D1 Washer o/l D2 Washer o/l Decker Washer o/l F (m3/hr)  Available  191 37 47 304 351 311 310 784 63 51 57 63 63 Used  121.0 301. Proposed Water Balance Network for Mill -1 Central Pulp & Paper Research Institute . Saharanpur . Saharanpur .Results for Mill –I Particulars Min. Fresh Water  191 Min. Fresh Water after PI  Consumption before PI 121 (considering TS and  COD as contaminants) Fresh Water Saving % 36 Units m3/hr M3/hr  - Central Pulp & Paper Research Institute . Fw Min. Central Pulp & Paper Research Institute . •Application of the mathematical programming model developed for water minimization has shown scope of water savings in both the mills after selecting suitable water networks. Saharanpur .Conclusion •The study conducted in selected mills in the pulp mill section has shown that PI studies can be a valuable tool for water conservation. Saharanpur .THANK YOU Central Pulp & Paper Research Institute .
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