Gas Flare Utilisation for SWCNT (Single-Wall Carbon Nanotubes) Production

Transcription

1 The Way Forward, 2012 Praxis Interactive Technology Workshop, 10 th to 13 th September, Istanbul, Turkey Gas Flare Utilisation for SWCNT (Single-Wall Carbon Nanotubes) Production Professor Ghasem Nasr Chair in Mechanical Engineering and Innovation Head of Petroleum and Mechanical & Gas Engineering Director of Spray and Petroleum Research Groups University of Salford Manchester September 2012

2 Outlines Gas exploration overview Definition of Gas Flare Gas Wells and Environment Zero Flaring Methods: Surface Network Design Zero Flaring Methods: Traditional SWCNTs SWCNTs: Using Sprays and Atomistaion (Proof of Concept) Benchmark Parameters Phase-I: Proof of Concept (University of Salford (UoS)) Aims and Objectives Operating Parameters Assembled Apparatus Design Characterisation of Fine Spray: Setup Results Overview Phase-II: Production of SWCNT Prototype: University of Oxford Operating Process Setup Result Overview: SWCNTs Closure 2

3 Gas exploration overview STOP IT!!! The Overall aim is to find an alternative of gas flaring Gas Re-Injection Excess Gas Conditioning for Processing Conditioning for Sale Natural Gas Liquid Recovery Reservoir Wells Fluid Separation (Gas-Oil-Water) Treated Gas for Plant Usage Crude Oil Fractionation Sales or Processing Water Treatment or Drain Crude Oil Storage Crude Oil Shipping Station To Terminals and Sales 3

4 Definition of Gas Flare Gas flaring is the burning of natural gas, which cannot be processed or sold during oil and gas production and processing operations. In past decade, gas flaring was believed to be not environmentally tolerable. Scientist have found that the flaring of gas is an impediment to the environment This has led to attempting to tackle the problem of gas flaring to advance it to an acceptable level worldwide 4

5 Gas Wells and Environment There are currently over 700,000 gas wells worldwide according to World Bank Data. About 110 billion cubic meter (bcm) of natural gas are flared annually. If all the flared gas is stopped and instead converted to hydrogen (H 2 ) and carbon (C) nanotubes, the reduction of CO 2 emissions which stands at 400 million metric tonnes per annum could be drastically reduced. The hydrogen component used for power generation and the irregular carbon nanotubes as composite materials. North America bcm Europe 3 bcm Middle East 16 bcm FSU bcm Central and South America 10 bcm Africa 37 bcm Asia 7-20 bcm 5

6 Zero Flaring Methods: Surface Network Design Existing Plant Storage Tank Heat Treater Flare Wellhead (s) Pump Re-Boiler (Instrument Scrubber) LP & HP Separators Knockout Drum (Flare Scrubber) Surge Drum (Test Separator) 6

7 Proposed Plant Zero Flaring Methods: Surface Network Design To Gas Transmission Line Gas O/P Crude Oil Crude oil o/p 7

8 Zero Flaring Methods: Proposed Surface Network Design

9 Zero Flaring Methods:Traditional SWCNTs Traditional methods for producing SWCNTs Arc evaporation of metal-doped carbon electrodes Vaporisation of metal-doped carbon targets Catalytic decomposition of molecules such as carbon monoxide and methane, supported metal particles. Single-Wall Carbon Nanotubes (SWCNTs), 96.3% C, 2.91% CO2 and 0.79% of other additives. These methods produce SWCNTs in small quantities Need to design equipment that should produce large quantities of SWCNTs. CH4 2H2 + C (SWCNTs) 9

10 Zero Flaring Methods:SWCNT Fe++ SWCNT CO2 and CH4 Fe++ Single-Wall Carbon Nanotubes (SWCNT) Multi-Wall Carbon Nanotubes (MWCNT) 10

11 SWCNTs: Using Sprays and Atomistaion Proof of Concept Phase-1:Proof of Concept (University of Salford) : Laboratory investigation using Sprays and Atomisation Water sprays <1micron: simulating Fe++ Air flowing into the water stream: simulating Methane Water (Fe++) Air (Methane) Phase-2: Prototype (Oxford University): Water eventually vaporised in the furnace (Oxford University trials) by converting CH4 to H 2 and C. The hydrogen component produced can be used for power generation and the irregular carbon nanotubes as composite materials. 11

12 Benchmark Parameters Furnace temperature up to 80 C Rate of addition of aqueous (Fe++) phase Rate of methane flow The low pressure of gas is better up to 1bar Liquid pressure up to 120bar l/min l/min 0.1MPa 12MPa All methane or only a portion can be used for the atomiser and the rest can be added separately 12

13 Phase-I, Proof of Concept using Sprays and Atomistaion: UoS Overall Aim: To develop an alternative approach to continuous gas flaring in oil and gas industry. Objective: Via experimentation using sprays and atomisation technique to produce Single Walled Carbon Nanotubes (SWCNTs)

14 Operating Parameters: Laboratory trials (Phase-I) Optimum Operating Parameters Methane (Air) pressure, MPa 0.1 Methane (Air) flowrate, l/min Liquid pressure (Water/Fe++), MPa 6 12 Liquid flowrate (Water/Fe++), l/min Temperature, o C Baffle plate position relative to base cover, mm Baffle plate position relative to aerosol tube, mm 3 10 Atomiser position relative to laser beam centreline, mm

15 Atomiser Choice: Spraying water (Fe++) The design specification of the atomiser: Produce droplet size as small as possible ( 1µm) Viscosity of aqueous phase about the same as water 15

16 Cascade Impactors Concept: Produce droplet size 1µm Stage-1 Inlet (Atomiser) Stage-2 Impaction Plate/Baffle Stage-N After Filter Filter Outlet 16

17 Assembled Apparatus Design The novel method of producing fine spray droplets using pressure atomisers and Impactor/ Baffle plate Air Line(s) Water Inlet Spray Atomiser(s) Baffle/Impactor plate Aerosol Tube Drain Line 17

18 Assembled Apparatus Design(cont.) The baffle plate was used to separate the larger droplets and to produce a fine spray (SWCNTs<1micron) in the aerosol tube of the device. The outlet of the tube was reduced to 15mm to narrow the spray stream slot. Both baffle plate and the tube were movable and their positions were changing during the trials in order to find the optimum set-up of the rig

19 Assembled Apparatus Design(cont.) 19

20 Characterisation of Fine Spray: Setup Atomiser Device Transmitter Receiver Laser Beam Fine Sprays Malver Mastersizer Laser PC Collection Tank 20

21 Characterisation of Spray: Setup (cont. ) Liquid Flow Meter Air Flow Meter Atomiser Device Liquid Return Line Pressure Gauge Air/Gas Source Liquid Tank Pump Fine Sprays Drain Tank 21

22 Characterisation of Spray: Setup (cont. ) The atomiser device assembly was placed in a vertical position above the laser beam of the Malvern Mastersizer-X. The air flow line (gas) was adjusted to working pressure of 0.1 MPa. The aqueous solution pump was started at the recommended pressure to deliver liquid (water) to the atomiser device.

23 Results and Data Processing Results were processed and compared with respect to : The baffle plate and the aerosol positions in the confinement tube. Water flowrate and pressure Air flowrate and pressure Atomiser position with respect to the laser beam

24 Results: Effects of Baffle Plate Drop size distribution at baffle plate and aerosol positions of 110 mm and 100 mm respectively Drop size distribution at baffle plate and aerosol positions of 80 mm and 100 mm respectively (Narrower Spray)

25 Results: Effects of Water Flowrate The increase in liquid flow rate at constant supply pressure increased the droplet size. At constant flow rate, increase in pressure decreased the droplet size.

26 Results: Effects of Air Flowrate The increase in air flow rate imparted a higher velocity to the water stream which resulted in a break-up of the stream into finer fragments and thus reduced the droplet size

27 Results: Effects of Atomiser Position The increase in air flow rate reduced the droplet size for downstream distance of 50 mm and above. The sudden drop of diameter at a distance of 40 mm, attributed to the high obscurescence level for the laser beam, travelling closer to the atomiser to be detected by the photodiodes.

28 Phase-II: Production of SWCNT Prototype, University of Oxford Operating Process Using Atomiser Device, spray liquid (Fe++) into the flowing Methane (CH4) Flowing methane over metal catalyst in a reaction chamber (Furnace) heated at a temperature of about 800 o C The chemical reaction that produced SWCNTs: CH4 2H2 + C (SWCNTs)

29 Production of SWCNT Prototype Setup: University of Oxford The designed atomiser device was then mounted onto the furnace (Model: Carbolite type, STF 16/450) Pressure Gauge Flow Meter Atomiser Device Power Supply Carbone Particle(s) To Hydrogen Tank (H2) Liquid Pump (Fe++) Furnace Liquid Tank

30 Typical SWCNT Particales (University of Oxford) Preliminary images of SWCNT particles, deposited as reaction products, using Transmission Electronic Microscopy (TEM). Subsequence test results will be published in due course.

31 Closure Phase-I (University of Salford) An atomiser device was designed and tested for zero flaring investigation for production of aerosol particle of <1micron for SWCNTs The droplet sizes using the device were found to be within the range of μm of (D n0.50 ) An increase in liquid (water/ simulating Fe++ catalyst) flow rate at constant supply pressure will increase the droplet size An decrease in the droplet size occurs as the air (simulating CH4)flow rate increases. The increase in air flow rate results in imparting a higher velocity to the water stream, which results in a break-up of the stream into finer fragments and thus reducing the droplet size The produced aerosol stream had droplet sizes of less than 1 µm as expected. The effect of water supply pressure and flow rate and the gas flow rate together with the downstream distance of the atomiser device on the droplet size distribution were investigated and characterised prior to Prototype trials at Oxford.

32 Closure In Phase-II (Oxford University) Preliminary results demonstrates that it is viable to produce SWCNTs from natural gas (mainly CH 4 ) that otherwise flared utilising the designed atomiser device assembly. The utilisation of flared natural gas for SWCNTs production will reduce the CO 2 emissions into the atmosphere.

33 Thank You & Have a good day