by chris heflin rachael houk mike jones a theoretical analysis of non-chemical separation of...
TRANSCRIPT
NANO-POROUS MEMBANES IN GAS PROCESSING
By Chris HeflinRachael HoukMike Jones
A theoretical analysis of non-chemical separation of hydrogen sulfide from methane by nano-porous membranes using capillary condensations from Chemical Engineering and Processing
INTRODUCTION
Natural Gas as it comes out of ground needs to have H2S removed before further processing Starting levels can be high (>5%) For US pipelines, limit is 4 ppm
Traditionally done through chemical means
One alternative is to use a nano-porous membrane to achieve a physical separation
Image Source: http://chemistry.about.com/od/factsstructures/ig/Chemical-Structures---H/Hydrogen-Sulfide.htm
CONVENTIONAL H2S SEPARATION
Traditional methods Wash with MEA, DEA, or other amines Use an oxide adsorbent
Disadvantages Consumes these chemicals Added hazards due to additional chemical
at site
AMINE WASH SEPARATION
Removes H2S, CO2, and mercaptans
Need a lot of equipment
Need both heating and cooling utilities
Image from http://en.wikipedia.org/wiki/Amine_gas_treating
OXIDE ADSORBENT
Excellent separation achieved Can have significant pressure drop Need high temperatures Use iron oxide or zinc oxide
Image from http://www.cwaller.de/sorbents.htm
CRITERIA FOR A GOOD MEMBRANE
Good selectivity in allowing H2S through and not CH4, only a small amount of CH4 dissolved in liquid H2S phase
Minimal pressure drop in bulk phase
MECHANISM
Bulk PhasePermeateH2S
H2S
H2S
H2S
CH4
CH4
CH4
CH4
CH4
CH4
FLOW
Nano-porous membrane
Not to scale
NANO-POROUOS MEMBRANES
Images from www.mdpi.com/1996-1944/3/1/165/ag sites.google.com/.../home/MAIN_NANO_2.jpgwww3.interscience.wiley.com/.../ncontent
TEMPERATURE VS PERMEABILITY
SEPARATION FACTOR
Where
x = mole fraction in the pore
y = mole fraction in the bulk
TEMPERATURE VS SEPARATION
So, How Are Nanoporous
Membranes Made?
SELF-ORDERING ELECTROCHEMICAL PROCESS A schematic diagram
showing pore formation by electrochemical self-ordering
A. Scheme of electrochemical cell for anodization and corresponding electrochemical reactions.
B. Scheme of pore formation, which includes several steps:
(I) the formation of oxide layer on metal surface;
(II) local field distributions caused by surface fluctuations;
(III) the initiation of pore growth by field-enhanced dissolution; and
(IV) the pore growth in steady-state condition
C. Typical current density curve obtained with anodization showing these stages
CYCLIC ANODIZATION
New development by Dr. Ducas Losic of the University of South Australia
A series of fabrication protocols to precisely control their most critical parameters, including pore diameters, pore geometry and surface chemistry
CONCLUSION
H2S separation is necessary: traditional methods are ok, but nano-porous membranes could do better
The H2S condenses and flows through the membrane to separate; this depends on temperature and pressure
Membranes can be made through self-ordering electrochemical process and cyclic anodazition
FURTHER RESEARCH
Gas mixtures of more than just methane and hydrogen sulfide, like actual natural gas
Optimized temperature and pressure Better manufacturing techniques,
particularly for large scale production Try a pilot plant scale testing
REFERENCES
http://en.wikipedia.org/wiki/Amine_gas_treating http://www.chem.tamu.edu/class/majors/chem470/Synthesis
_Gas.html http://www.thefuelman.com/Documents/H2S_removal.pdf http://en.wikipedia.org/wiki/Hydrogen_sulfide “Engineering of Nanomembranes for Emerging Applications”
by Dr. Ducas Losic http://www.azonano.com/details.asp?ArticleId=2445
“Simple and reliable technology for manufacturing metal-composite nanomembranes with giant aspect ratio” by Jovan Matovića and Zoran Jakšić http://www.sciencedirect.com
“Self-ordered nanopore and nanotube platforms for drug delivery applications” by Dusan Losic & Spomenka Simovic http://informahealthcare.com/doi/pdf/10.1517/17425240903300857?cookieSet=1
Group S2 rebuttal
Chris HeflinRachael Houk
Mike Jones
• Data used showed amine needed to be replaced slowly with a fresh stream because some of it leaves in the tail gas stream
• No info available on the cost of the nano-porous membrane to compare with traditional methods
• The presentation was right after Dr. Seminario did a harsh critique of a previous presentation, so there was reason to be nervous, but we should have rehearsed more.
• Thanks for the feedback on the animation and introduction. We’ll try to continue this practice in our future presentations.
Group S1
Group S1Review of Nano Membranes for Gas
Separation
Notes on Presentation
Positive Notes• Good at answering
questions• Separation animation was
helpful• Summary of chemical
method was thorough and educational
• Good analysis of research and future development needs
Opportunities for Improvement
• Presentation was very short– Could have included more
information and spent more time on use and applications
– Lasted less than 15 minutes
• More eye contact during presentation
• Cite sources on slides– Could not have known due to
guidelines being presented right before
Group S1
Grade
• Slides (20/20)– Informative, well designed
• Oral presentation (19/20)– Good skills but needed more eye contact
• Graphics (18/20)– Needed a few more pictures and diagrams
• Educational Value (20/20)– Topic was well explained
• Group Analysis of Research (19/20)– Needed a little more research on topic for thoroughness
• Overall (96/100)
Group S1
GROUP S3Review: nanoporous
membranesGroup S3:
Michael KoettingBradford Lamb
James Kancewick
Review
The presentation was informative and the slides were generally well done.
Student questions were answered confidently and in detail.
Presentation was not too detailed to be understandable by the audience, yet still detailed.
Review
Speaking could have been more polished, with more eye contact from some of the speakers and less reading from slides/notes.
Some figures in the slideshow were not explained, so they added very little to the presentation.
Despite this, however, the presentation was very good on the whole.
Scott MarwilDanielle MillerJoshua Moreno
Group S4
Group S4Review of Nano Membranes
for Gas Separation
Things Done Well
Very good job with the illustrations and the animations The group did a good job of answering the classes
questions in a full and in-depth manner The group members presenting knew the material and
did an good job relaying that knowledge onto the rest of the class
The Group was very well spoken They made good use of animations and pictures to
illustrate points Their introduction was very thorough and well written The material was presented in an interesting and
exciting way
Group S4
Things That Need Improvement The overall presentation was a little on the short
side. The group needs to develop a better introduction
to introduce the topic and background to the class instead of just jumping to the heart of the material so quickly
Sometimes the slides contained a bit too much information. They should try limit the amount of information on the slides so they can draw attention to the speaker.
The Not-So-Good
Group S4
Pradip RijalJason SavatskyTrevor SeidelLaura Young
Group S5
Group S5Review of Nano Membranes for Gas
Separation
Presentation Review
• The groups power presentation and visuals were very well done.
• They probably should have practiced the presentation a little more. The oral presentation was weak and unfocused.
• Their attire was appropriate for the occasion.
Group S5
John BaumhardtDaniel Arnold
Michael TrevathanMichael Tran
Group S6Review of Nano Membranes for Gas
Separation
Review
• Slide layout was agreeable and pleasant to look at.• The presentation was detailed and well thought out.• The further research section is a little weak (the
natural gas composition could have included a sample composition of “actual natural gas”
• The presentation overall was quite good, but the presenters seemed a little nervous, and were reading off of the slides.
Review of Information• From a natural gas background, the disadvantages listed are
not valid. In an amine system, there are no chemicals stored on site because there are very few reasons to change the amine. Apart from wanting to try a more efficient amine, standard amine reclamation (cleaning) can be performed to regenerate the existing amine.
• Even without regeneration, amine lasts years in plants without replacement.
• We would have liked a cost comparison of the nano-porous membranes vs the traditional amine, to determine the commercial viability of the membranes in gas plants.