Mixed Salt Recovery for High Quality Pulp (MSRP)

Transcription

1 Mixed Salt Recovery for High Quality Pulp (MSRP) Green Manufacturing for Sustainable Business Waste to Value Cost saving & Environment Dr. Jirachote Phattaranawik and Team Central R&D, SCG Chemicals

2 Topics Waste to Value Cost saving & Environment 1. Project background and motivation 2. Project development 3. Mill-trial operation and benefits 4. Commercialization and extended works

3 1. Project background and Motivation SCG s policy 1) Supporting green manufacturing 2) Increase operation flexibility (High flexibility) Waste to Value Cost saving & Environment Objectives 1) Recycle /reutilization of spent caustic in other applications 2) Develop own technology to recover the spent caustic 3) Develop product from raw spent caustic for reuse 4) Develop utilization/consumption method of treated spent caustic Targets to achieve at ROC 1) Reduce operating cost/treatment cost of this spent caustic (mixed salt liquor) Approximately 55% reduction or 20 MB/year 2) Reduce amount of water discharge from ROC- 33% reduction or 160,000 m3/year 3) Achieve product quality & price for pulp mill application and other reuses

4 1. Project background and Motivation Rationale : 1) expensive treatment cost, 2) toxicity and 3) environmental concern Spent caustic line: 33% flow Treated Spent Caustic by wet air oxidation (WAO) Diversion Box the worst trouble for waste water system 6 m 3 /hr m 3 /hr High toxicity Very difficult to treat Dilatants for spent caustic Cost for treatment -55% for spent caustic treatment (40 B/m3)- most expensive/ costly - Total cost is 72 B/m3 Wastewater treatment Plant 22% flow 45% flow Alternative solution: Dilution Steam B/D Cooling B/D Already implemented (RO unit) 20 m 3 /hr 40 m 3 /hr High organic load Low organic load Discharge -High salt (TDS) in the discharge - Conflicted (potentially) with new regulation Recycle/reuse Spent caustic system by using own competitive technology Find the Benefit from salt extract from Spent caustic

5 1. Project background and Motivation Waste to Value Cost saving & Environment Applications & Potential for reuse 1) Pulp and Paper Mill Valuable salts: NaOH, Na 2 S, Na 2 CO 3 1. Max. benefit to both SCG chemicals and Paper 2. Ease for investigation/development 2) Fabric dyeing process 3) Leather tanning Internal By-Product Synergy (i-bps) Central R&D SCG Chem Phoenix PPP SCG Paper Cross business units R&D SCG Paper ROC SCG Chem Waste Caustic salt from ROC Innovation/ Technology Product Kraft recovery process at Phoenix Pulp and Paper 1. External party 2. Market size is large, but variety (difficult for QC) 3. Need more study

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7 1. Project background and Motivation At ROC, SCG Chemicals Rational - Very high treatment cost for MSL - High TDS (salt) discharged wastewater - Environmental problem (water & odor) Benefit to ROC 1. Wet air oxidation (~20-30 mil. Baht/year) -High Pressure Steam Plant Air, Turbine Steam Condensate, Cost of electricity consumption 2. Waste Water Treatment Plant (~2-4 mil. Baht/year) -Chemicals for Treatment, Cost of electricity consumption Waste to Value Cost saving & Environment At Phoenix PPC-SCG Paper Rational - Low efficiency at recovery boiler to convert Na 2 SO 4 to Na 2 S - Heavy metal contaminated Benefit to Phoenix 1. Value of chemicals (Salt cake) (~2-5 mil. Baht/year) 2. Energy saving at recovery boiler (~0.2 mil. Baht/year), Prelim: Mixed salt liquor is used to : 1) Replace directly a salt cake 2) Easier utilization without incineration & energy saving

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9 2. Project development 1) Get and analyze the Customer s requirement Workshop: R&D Chem and Phoenix for customer survey and requirement - Quality of product MSL required by Pulp Mill - Comparative analysis Quality Phoenix Pulp and Paper Green liquor ROC Raw spent caustic 1. Suspended solid (SS) Lower than 100 ppm ppm 2. Total oil and grease Lower than 60 ppm ppm Remove: SS and red oil from spent caustic 3. Total heavy metal Lower than 50 ppm ppm 4. Total active alkaline ppm 50 ppm 5. Reaction efficiency with CaO 75 85% 80%

10 2. Project development 2) Select and develop the technology based on customer requirements Technology & process development to recover the mixed salt liquor (MSL) Criteria for selection: Experimental work & conceptual Design 1) Chemical and physical processes able to remove red oil and suspended solid from raw MSL at high ph 2) High efficiencies for red oil removal and suspended solid removal at reasonably low operating cost 3) Reasonable investment cost, risk assessment for operation, safety issue 4) Ease of integration and upgrading Waste to Value Cost saving & Environment

11 Available technologies for raw MSL (spent caustic) Treatment (Shopping list)- Need own development? Factor/ commercial process Wet air oxidation Electrodialysis Liquid-liquid extraction Chemical precipitation Membrane technology Operating condition 40 Bars, 200 C ED cell, high voltage atm, 2 stages Atm, room temp Process complexity Easy Moderate Moderate Easy Easy Removal efficiency 1) Red oil 2)Suspended solid Concern 1) High 2) Low Secondary waste generation 1) High 2) Low Safety, expensive maintenance 1) High 2) High Need toxic organic, safety issue 1) Low 2) Low Low removal efficiencies 6 bars, room temp. 1) Low 2) High Short membrane lifetime Investment 60 MB 100 MB 120 MB 50 MB 80 MB Operating cost (per Kg dry product) 8000 B 6000 B 6000 B 3000 B 5000 B Problems: NOT a cost-effective process for SCG 1) Infeasible due to high investments and high operating cost 2) Large amount of toxic waste generation 3) Not able to remove both items in the same time

12 2. Project development Waste to Value Cost saving & Environment Development of own technology: 1) Single process (Remove both) or integrated (hybrid) process (Remove each, twice) 2) Performance/cost: The hybrid process is much cost-effective. Technology Performance & operating cost Investment Ultrafiltration (UF) with treatment chemicals 1) Good for oil and solid removals 2) 1200 B/kg salt 30 MB High-speed centrifuge 1) Good for oil and solid removal 2) 1200 B/kg salt 70 MB New invention of MSRP process - Hybrid - Removals oil and suspended solid 1) Good for oil removal (lower than 50 ppm) 2) Good for solid removal (lower than 100 ppm 3) B/kg salt 6 MB selected

13 2. Project development Waste to Value Cost saving & Environment 3) Product development MSRP process MSRP process Red oil solid removal Product Product on spec. -Red oil lower than 50 ppm - Suspended solid lower than 100 ppm

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15 2. Project development 5) Project evaluations from customer - Great potential for chemical saving - Mill-trial operation is in demands by Phoenix Pulp and Paper, SCG Paper team - No impact hand sheet quality and process/unit operations 6) Mill-trial scale operation to prove benefits on both ROC and Phoenix Pulp and

16 MSRP benefit calculated from plant trial Mixed salt liquor (MSL) (Spent caustic) from ROC MSRP process Phoenix Kraft s recovery line 1 MSL = 370 tons Loading MSL for 10 days -7.6 days in TK Stop WAO for 2.4 days At ROC saving cost 0.11 MB in 2.4 days Mixed Salt cake = 18 tons Better than expectation At Phoenix PPC, 0.34 MB for 10 days or 5 MB/year (batch operation) 1. WAO: 15.6 MB/year 1. Reduce salt cake: 64 tons, 10% better than expectation 2. WWTP: 0.55 MB/year 2. 20% reduction in bleaching agent: over expectation Total: Cost Saving 16.1 MB/year 3. 3% Better pulp quality (strength and whiteness): over expectation High performance by-product 1) Cost saving and 2) production improvement

17 4. Commercialization and extended works Commercialization and full-scale plant operation 1. Successful own development technology 2. Produce acceptable product quality for both lab and pilot-scale plants and cost-saving value for ROC is practically obtained. 3. Proposal for full-scale plant at ROC was endorsed for 70 MB: Current works/activities to support the full-scale plant 1) Preventive/counter measurements to plant variation 2) Legal issues: EIA, official permission, insurance, waste to product. 3) Internal business model within SCG

18 Extended plan for innovation development Total Benefit (MB) to all SCG Within SCG MOC Thailand PTT, IRPC, refinery plant Regional AEC Indonesia, Vietnam Worldwide Technology value: 80 MB/year USA, Canada, Brazil, South Africa, China, Licensing/technology package/know-how transferring-exchanging 30 ROC Cost-saving, environmental benefit, CSR, Zero discharge Start Year 2023

19 Project Conclusion: Sustainability & Synergy & Collaboration Cross-BU collaboration Internal By-Product Synergy (i-bps) Waste to Value Cost saving & Environment