Project: HAZOP Study for Distillation columnDesign Intent: To purify formaldehyde as the bottom product, and unreacted methanol as overhead product. Node: Feed (mixture of water, methanol and formaldehyde) from Absorber C-002 entering Distillation column C-003, including Reboiler (RB-1 (E-101), Reflux drum (RD-102), and Pump (P-007-1/2) Operating Condition: Op. Pressure: 101.3 KPa Op. Temperature: 100 deg C (Column) Drawing No: Ref No. N1.01 Parameter Flow Guideword More Cause 1. Malfunction of LCV001. 2. Malfunction of FCV001. 3. High reflux N1.02 Flow No/Less 1. LCV-001 stucked close. 2. Clogging 3. Line leak at feed N1.03 N1.04 N1.05 Flow Pressure Pressure Reverse High Low N/A N01.6 N01.7 Vacuum Temperature High 1. Condenser failure. 2. Malfunction of FCV003. N01.8 Temperature Low 1. Reboiler failure. 2. Malfunction of FCV003. 3. Excessive reflux. 4. FCV-001 fails open N01.9 Level High 1. Blockage of distilation outlet 2. Failure of active pump P-005-001/2 3. Failure of FCV-002 N01.10 Level Low N01.11 N01.12 N01.13 Start-up/Operability Shutdown/Maintenance Corrosion/Erosion High N01.14 N01.15 Composition Others 4. Low reflux causing high level buit up in reflux drum 1. FCV-002 stuck open Low pH due to the present of acid or salt in the distillation overhead system at the right condition exist. unreacted methanol as overhead product. Absorber C-002 entering Distillation column C-003, including Reboiler (RB-103), Condenser Date: Node: Node Rev. No. Consequence Safeguards 1. Overpressure within C-003 leading to flooding in the Rectification section, in the worst case explosion. 2. Product offspec. No. 1 Drawing Rev. No. Recommendations Recommendation Consider to install High flow alarm and high high flow trip (after LCV-001) to stop the flow. 1. FICA-1013 high flow alarm. 2. FICA-1010 1. FCV-001 2. FICA-1013 high flow alarm No product, financial loss due to shutdown. Potential fire and explosion in the presence of ignition source. 2 3 Consider to install Low flow alarm. Pressure gauge routine inspection. Material selection 4 High temperature leading to high FICA 4008 high high vapor pressure built up in the temperature trip reflux drum, in the worst case can cause reflux drum rupture,leading to potential fire/explosion hazard. 1 Consider to install High flow alarm and high high flow trip (after LCV-001) to stop the flow. Product off spec and potential overpressure 1 Incomplete separation leading to product offspec. Incomplete separation leading to 1. FCV-001. product offspec. 5 Recommend to install high temperature alarm and flow control valve at the outlet of RB-103 into C-003. Routine inspection and maintenance. Recommend to install low temperature alarm at the outlet of RB-103 into C-003. 6 Refer to More Flow. 1. FCV-003 2. FICA 1013 3. TICA-1006 low low temperature trip 1. No product. High level built up 1.LT- 2005 2. in the distilation column leading LICA 2005 3. to rupture of distilation column Bypass 1 Consider to install High flow alarm and high high flow trip (after LCV-001) to stop the flow. 1 Consider to install High flow alarm and high high flow trip (after LCV-001) to stop the flow. 1. No product. High level built up 1.LT- 2005 in the distilation column leading 2. LICA 2005 to rupture of distilation column 1 Consider to install High flow alarm and high high flow trip (after LCV-001) to stop the flow. 1. Potential for liquid to backflow into the distillation column. 1 Consider to install high level indicator controller at the reflux drum. To install a level low low trip to trip the pump. 1. No product. High level built up 1. 2x100% pump P005in the distilation column leading 1/2 2. to rupture of distilation column LICA 2005 3. LT2005 1. Potential for gas blowby leading to pump cavitation. 1.LT- 2005 2. LICA 2005 Consider installing level control valve (from C-003 to Pump P-0051/2) 1.Contribute to piping leaking 1 Chemical Injection such as Corrosion Inhibitors which include neutralizers. 2 Change of material from carbon steel to stainless steel which is much more durable to corrosion and increases the life time of the plant. 3 Installation of pH meter and low pressure alarm. 2.Increasing and decreasing of tower pressure drop. 3.Inadequate separation leading to reduction in product capacity and purities (product outspec) 4.Instrument issues such as the leads line to instrumentation plugging 15th Nov 2014 1 A Recommendations Action By Project: HAZOP Study for Absorption Column for Nox Design Intent: To remove unwanted reacction heat and to reduce the absorber tray temperatures to favour absorption. Node: Cooling water inlet, cooling coils within the absorption column and cooling water outlet. Operating Condition: Op. Pressure: 950 Kpa (Column) Op. Temperature: 8-65 DegC (Column), 28 degC (cooling water in) Drawing No: Ref No. Parameter N1.01 Flow More Cooling water inlet valve More cooling water leading to stucked open. product offspec. N1.02 Flow No/Less 1. Blockage of cooling water inlet. 2. Cooling water inlet valve stucked closed. N1.03 N1.04 Flow Pressure Reverse High No foreseen hazard. High pressure due to higher pump discharge pressure from cooling water system. N1.05 Pressure Guideword Low Cause Consequence Loss of cooling water will lead to Nox gas being reliefed to stack. 1. Line leak/rupture in the absorption column, in the worst case leading to offspec of product. 1. Blockage of cooling See N1.02 No/Less flow above. water inlet. 2. Malfunction of cooling water inlet valve mperatures to favour absorption. ater outlet. Safeguards No. 1. TIC to control the 1 cooling water inlet valve. 2.Low temperature alarm 3. SOP 1. Low Flow alarm at inlet of cooling water inlet. Date: Node: 9th Nov 2014 Node Rev. No. A 1 Drawing Rev. No. Recommendations Recommendation Action By To connect Temperature columm Instrument/Control indicator to FIC at make-up water. Engineer 2 Consider to install Column temperature high alarm Mechanical/Process/In strument Engineer 3 Consider to install Column temperature high trip. Mechanical/Process/In strument Engineer Consider to install a pressure relief valve (relieving liquid pressure) at upstream of the cooling water inlet. Mechanical/Process/In strument Engineer 1. start-up procedures for 4 cooling water system. 5 Consider to install a bypass valve at the cooling water inlet. Process/Mechanical Engineer 6 Consider to introduce chemical Process/Mechanical injection (i.e. corrosion inhibitor, /Instrument Engineer biocide, sodium hypochloride) into cooling water supply to ensure that the cooling water specs to be maintained to avoid scaling, corrosion and algae formation.