ENGINEERING SPECIFICATION ASU TYPE NITROGEN GENERATION UNIT FOR DIESEL HYDROTREATER UNIT FOR HINDUSTAN PETROLEUM CORPORATION LTD.

Transcription

1 ENGINEERING SPECIFICATION FOR DIESEL HYDROTREATER UNIT FOR HINDUSTAN PETROLEUM CORPORATION LTD. VISAKH REFINERY DHT PROJECT TEIL JOB NO. : 6261 DOCUMENT NO: A A 16-March-09 For Client s approval SPS SW SVW Rev. no. Issue Date Description Prepared by Checked by Approved by TOYO ENGINEERING INDIA LIMITED MUMBAI INDIA

2 DOC.No A DHT PROJECT Page 2 of 10 TABLE OF C O N T E N T S 1.0 SCOPE TECHNICAL REQUIREMENTS GENERAL AIR COMPRESSOR SYSTEM RE COOLING UNIT / REFRIGERATION UNIT: AIR PURIFICATION UNIT COLD BOX DISTILLATION COLUMN EXPANSION TURBINE EXCHANGERS (INSIDE COLD BOX) LIQUID NITROGEN TRANSFER PUMP STORAGE TANK VAPORISERS CONTROL SYSTEM GENERAL DESIGN REQUIREMENTS CODES AND STANDARDS PERFORMANCE TESTING INSPECTION TESTING AND PERFORMANCE GUARANTEE 9

3 DOC.No A DHT PROJECT Page 3 of SCOPE This Engineering Specification together with requisition/tender, attached data sheets covers the requirement to be met by bidder in the process detail engineering, fabrication, inspection, testing and supply, erection and commissioning of ASU type Nitrogen Generation ni The enclosed specification is intended to give the vendor the functional requirements and operating conditions the plant must fulfill. Vendor shall use the state of the art technology with greatest energy efficiency so as to reduce the power consumption to a minimum. 2.0 TECHNICAL REQUIREMENTS Minimum Technical Requirements mentioned below shall be followed during designing Nitrogen Generation Unit: 2.1 GENERAL The plant shall be based on liquification of air (cryogenic type) and of modular construction & skid mounted for various units like Air Compressor unit, Refrigeration unit, Adsorber unit, Cold box, liquid N 2 storage, Vaporizer. Vendor to include liquid Oxygen storage and distribution, if specified in data sheet The air separation process should include below steps:- Compression Pre cooling Purification Cooling to liquid air temperature Separation into components by low temperature distillation Re-warming of Separated components Storage Vaporization 2.2 AIR COMPRESSOR SYSTEM Bidder to provide Air Compressor as specified in Data Sheet Air Compressor shall be sized to discharge air at all operation conditions specified The air compressor for the Nitrogen generation Plant shall be Centrifugal type driven by Electric motor There shall be 2 numbers (1 W + 1 S/B) of compressor running at 100% capacity. Unless specified otherwise The Centrifugal Air compressor shall be in accordance with API Inlet silencers and fresh air filters shall be provided at the suction of the compressor. The filter construction shall have suitable provision to prevent water ingress into filter/silencer due to rains and also provide a bird screen Air Compressor should be as per Standard Specification of Centrifugal Compressor attached elsewhere.

4 DOC.No A DHT PROJECT Page 4 of RE COOLING UNIT / REFRIGERATION UNIT: Refrigeration unit for pre-cooling air shall be vapour compression type. The complete skid mounted unit shall be used for precooling of air. It shall consist of compressors (1W+1S),water cooled condensors,expansion valves and evaporator coils It shall have fully automatic operation and the turndown of the unit shall be synchronized with the air separation unit turndown The refrigerant to be used shall be environmental friendly unless otherwise specified or approved by the Owner A local panel for the refrigeration unit is to be provided which shall be skid mounted Air cooled type refrigeration system to be considered in case cooling water is not available Moisture Separator to be provided to remove max. free moisture from the cooled air Refrigeration unit should be as per Standard Specification for Refrigeration unit, attached elsewhere. 2.4 AIR PURIFICATION UNIT The Air Purification Unit shall be twin bed desiccant system type. The desiccant shall be activated alumina and molecular sieve or manufacturer standards designed to completely remove balance moisture, carbon dioxide, hydrocarbons and other gases to make the air suitable for cryogenic air separation plant. There will be two vessels in the system. One will be under adsorption and another will be under regeneration Two pre filters and two after filters one working and one stand by shall be provided. After filter at the outlet of air purification unit to arrest dust up to 5 microns with 99% efficiency. Filter elements shall be cleanable without dismantling the pipe work The regeneration heating shall be done by means of an electric heater. Adsorber Unit shall be regenerated by waste N 2 coming from cold box Adsorber Unit shall be fully automatic in operation with provision for manual operation from field Each Adsorber shall be equipped with a suitable corrosion resistant austenitic stainless steel screen for desiccant support. Screen shall be in suitable sections so as to facilitate replacement through manhole. Provision shall be made for replacing and removing desiccant without dismantling the connected pipe work One number online dew point analyzer, one number CO 2 analyzer shall be provided at the exit of the after filters Each Adsorber shall be fitted with safety valve. Pressure and temperature gauges at the air inlet and outlet of each Adsorber shall be provided Material of construction (carbon steel) of all pressure vessels shall be SA 516.Gr.60/70.Forging SA 105,Nozzle pipes SA 106,Fitting SA 234,Bolting SA193 Gr B7 & SA 194 Gr 2H The dynamic adsorption capacity of desiccant to be used for design shall be 7% Maximum for activated alumina Unit package shall have the following features.

5 DOC.No A DHT PROJECT Page 5 of COLD BOX Suitable valves of non lubricated type operated by pneumatic actuator for cycle change over. Provision of repeat indication / annunciation of major parameters in main control room One (1) no. cold box shall be provided enclosing the distillation column, main heat exchangers and expansion turbines and all interconnecting valves and piping The inside of the cold box shall be sufficiently insulated to prevent ingress of heat by perlite insulation Suitable access doors shall be provided for expansion turbine. Suitable access doors for maintenance of the equipment inside the cold box shall be provided. All valves requiring manual operation shall have handles outside the cold box The cold box shall be internally provided with ladders, platforms and access doors at various levels for accessibility for maintenance The material for column, vessel shells, piping inside the cold box shall be austenitic stainless steel. For plate fin exchangers, aluminum alloy material shall be used. Stainless steel material where ever applicable shall be low carbon grade of 304L, 316L or stabilize grades 321/347 shall be used. ASME/ASTM grades shall be specified in contractor s document. Bidder may propose material of construction for column, vessels etc. on aluminum alloy if they have minimum two year experience of similar application of similar capacity All indicating instruments shall have its indicating dial brought out of cold box Electrical type Deriming Heater shall be provided and shall have adequate safety and control instrumentation The various liquid drains from the cold box shall be connected to a stack where the liquids are vaporized by means of dry air. Stack shall be of stainless steel material. Bidder to check necessity of Blower for vaporization & provide accordingly. 2.6 DISTILLATION COLUMN Distillation column shall be provided for separate N 2 from air. Bidder to also separate O 2 etc. if specified The column shall be made of stainless steel material of low carbon content and designed as per ASME Sec. VIII Div. I The trays/structural packing provided inside the column shall be suitable for efficient separation of product gas/liquid & to achieve the required purity in the entire turndown range The column shall be equipped with all necessary instrumentation and control for level, liquid transfers, pressure differential, temperature indication etc. 2.7 EXPANSION TURBINE Expansion turbine shall be provided. The expansion turbine shall be connected to brake

6 DOC.No A DHT PROJECT Page 6 of 10 system Necessary control system shall be provided for temperature control & turndown Lube Oil System / braking oil system considering of oil reservoir of adequate capacity, oil pump, oil cooler, S.S. Piping, duplex filters, oil pressure and return oil temperature gauge, pre alarms & trips for low oil pressure shall be provided A local gauge board containing tachometer, bearing/return oil temperature alarms for over speed, low seal gas pressure etc. shall be provided., 2.8 EXCHANGERS (INSIDE COLD BOX) The exchangers shall be multi pass plate type brazed aluminum construction Bidder to specify number of exchangers and its various locations inside the cold box along with its specification. 2.9 LIQUID NITROGEN TRANSFER PUMP Bidder to provide liquid nitrogen transfer pumps, if specified Suitable control & protection system to be provided The pumps should be as per manufacturer s proven experience STORAGE TANK Liquid nitrogen double wall storage tanks with stainless steel inner shell contained within a carbon steel outer shell shall be provided Capacity of the tanks shall be as specified Both inner & outer shell to be designed as per ASME Section VIII, Div The space between the shells shall be filled with perlite insulation and maintained under vacuum to reduce the heat leak into the tank Hose connection to be provided for tanker unloading, unless otherwise specified Facility for liquid nitrogen injection from storage tank to distillation column shall be provided The tanks shall be fitted with a pressure building coil to raise the operating pressure of the tank suitably in order to meet Vaporizer capacity VAPORISERS Vaporizer should be atmospheric type or steam / water / fired heater type as specified in the Data Sheet Atmospheric Vaporizer should be provided with two sets. One set will be under defrostic mode when other set will be in vaporization mode. Changeover should be automatic unless specified otherwise the change over shall be required after every 8 hours continuous operation. They shall be vertical with aluminum fins Steam / water / fired heater type Vaporizer should be designed for the utility specification applicable for the job All necessary control & protection system to be provided for the vaporizer.

7 DOC.No A DHT PROJECT Page 7 of CONTROL SYSTEM Oxygen and C0 2 analyzers shall be provided for measuring the quality of the product gas The plant shall be capable of fully automatic operation once started. The control and monitoring of the plant shall be from the control room unless otherwise specified control system shall include all safety features comprising of interlocks, alarms, trips etc. for all sub-packages Control system should also operate the N 2 plant at different operating mode such as max generation case, max L/N case etc Following interlocks /alarms indication shall be provided on the skid as a minimum. As applicable for the system.: Interlock system to ensure that regeneration system is initiated only when the valves are switched on in correct position. Audio-visual indication to indicate failure to switch over of valves Audio-visual indication to indicate flow in regeneration circuit. Indicating lamps for control panel on, Adsorber under operation, regeneration on, timer on etc. 3.0 GENERAL DESIGN REQUIREMENTS Following General design requirements shall be followed for Nitrogen Generation Plant. 3.1 Air Compressor, Refrigeration and Purification Unit shall be located in a shed. The rest of the equipment shall be located outdoor. 3.2 The entire plant shall be paved and the area around the ambient air vaporizers shall have gravel. 3.3 Ease of operation and maintenance including any necessary measures for ensuring safety of personnel and equipment as well as a conducive working environment. The layout of the nitrogen plant and storage system shall be in accordance with local & statutory regulations and have adequate access for regular operation & maintenance. 3.4 Corrosion allowance for carbon steel vessels shall be minimum 3mm. 3.5 All couplings, gears, and exposed rotating parts shall be provided with adequate protection guards. 3.6 Vendor shall furnish plant and equipment layout (along with the bid) taking care of the available space. The piping for utilities and products shall be terminated at the battery limit. 3.7 Companion flanges for non-standards flanges shall be provided by manufacturer along with spiral wound gaskets of required grades and fasteners. 3.8 All ties in points at the battery limits shall be provided with isolation valves. 3.9 Silencers shall be provided wherever air or gas venting upto a suitable height is involved to minimize noise level to 85 dba at 1 meter from the silencer The units shall be shop assembled to the maximum extent practical to minimize on site erection work Plant shall be designed for turndown operation and venting of air or product shall be

8 DOC.No A DHT PROJECT Page 8 of 10 minimized to achieve turndown It shall be contractor s responsibility to comply with all relevant requirements of static and mobile pressure vessel (SMPV) rules of CCOE, Nagpur, etc Compliance with applicable national or overseas codes and standards as well as any statutory regulations in existence for a specific item Vendor shall furnish detail write-up of the process of cryogenic within the distillation columns with respect to pressure and temperature and the achievement of purity of Nitrogen All the Sub-Vendors shall have proven track record of supply of similar equipment/items and selected equipment model must have been supplied in two such plants out of which one unit must have worked satisfactorily for 8000 hours to major items such as Air Compressor, exp turbine, liquified N 2 tank, Vaporizer etc Owners/PMC approval shall be taken for all makes not mentioned in the vendor list Bidder shall supply and install all maintenance facilities sized for handling the heaviest single place of equipment for maintenance. The maintenance facilities like EOT/HOT cranes, hoist, chain pulley blocks and monorails for all units covered in the subject package shall be provided. Contractor shall provide sufficient space for maintenance, dismantling and platforms for maintenance as specified D model of Nitrogen Plant shall be prepared in PDMS, if asked. It shall include all details like pumps, drives, vessels, piping platforms etc. Owner / PMC / Purchaser shall witness model review conducted at vendor s center. 4.0 CODES AND STANDARDS The latest edition of following codes and standards shall be applicable for design, engineering for the Nitrogen Generation Unit. a Pressure Vessels -ASME Sec.VII1 Div. I & ASME Sec.IX b Heat Exchangers -TEMA C and ASME Sec.VllI Div c Air cooled exchanger -ASME Sec.VIII Div.I, API 661 d Piping, valves, fittings -ANSI.B 31.3, ANSI-B 16.5 e Centrifugal Air compressor -API 672 f Main Heat Exchanger (with Cold Box) ALPEMA 5.0 PERFORMANCE TESTING 5.1 Contractor shall conduct performance test run of the plant and the following parameters shall be complied at full load. Nitrogen capacity (gaseous & liquid) Battery limit condition (at outlet of N 2 plant). 5.2 The following parameters shall be demonstrated by the contractor during performance test. Capacity & Purity of the unit

9 DOC.No A DHT PROJECT Page 9 of 10 Dew point of N 2 at the outlet throughout the cycle including Cycle change over period Pressure drop across the unit Electrical Power consumption 6.0 INSPECTION TESTING AND PERFORMANCE GUARANTEE 6.1 Typical ITP is attached elsewhere for reference. Bidder to propose Inspection & Test plan, QA / QC, etc. along with their offer. 6.2 Purchaser, as specified, witness Vendor s Inspection & Test and review test document. 6.3 Witnessed by Purchaser s inspector shall in no way relieve Vendor & has responsibility to meet the specification. 6.4 Extent of test / inspection at shop would be as follows. I. Visual inspection II. Dimensional chart III. Hydrostatic test IV. Radiographic examination & other NDT V. Material certificate & other document review 6.5 Specific test requirement for Air Compressor I. Over speed test (SPIR test) II. Balancing test III. Hydrostatic test IV. Mechanical run test V. Shaft seal test (for liquid film N2 mechanical contact shaft seal) VI. Performance test when specified 6.6 Performance test for Nitrogen generation Unit to be carried out. The duration of the test be for 72 hours for gaseous and liquid production. 6.7 Performance / mechanical run test (as applicable) to be carried out for expansion Turbine. 6.8 FAT for control system to be carried out.