The SWAP: A Breakthrough in Hydrogen Sulfide Processing

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The SWAP: A breakthrough in hydrogen sulfide processing," presented by CEO Wolf Koch, to Sulphur 2011 Conference & Exhibition, Houston, November 10, 2011.

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The SWAP: A Breakthrough in Hydrogen Sulfide Processing

  1. 1. Background 2  is  available   2SWAPSOL  Corp  is  developing  commercial  pro- 2 S  will   S)   2 react  readily  with  oxygen  or  it  may  be  used  to  recover   hydrogen.technologies.  The  most  basic  of  these  developments     2H2S  +  O2  ==>  Sulfur  +  2H2O         3  is  the  relatively  low  temperature  catalytic  decomposi-   H2S  ==>  H2  +  Sulfur           4   2 2 )  and  sulfur,  the  second   2 S  with   If  reaction  path  3  is  chosen,  the  analog  to  Reaction  2   2 O)  and  sulfur,  and  lastly  the   is  not  possible  since  the  presence  of  both  methane   2 and  oxygen  represent  a  potential  safety  hazard;  in   2 O,  sulfur  and  a  carbon-sulfur  polymer.  The  SWAP   - from  the  gas  stream  and  treated  in  a  separate  oxida- 2 S  to  below  detectable   -and  Claus  tail  gas  cleanup.  A  related  process  allows   lent  processes  that  produce  water  and  sulfur.for  the  destruction  of  waste  hydrocarbons  to  form   2 2 S  source  where  it  is   Carsul  formation  has  been  reported  in  the  literature  as  not  otherwise  available;  further  processing  allows  for   an  undesirable  solid  byproduct  in  the  conversion  of  the  production  of  hydrogen  and  sulfur  as  well  as  the   organic  sulfur  compounds.  We  have  also  found  refer-recovery  of  sulfur  and  carbon-based  polymers  from   ences  to  carsul  formation  in  catalyst  vendor  literature  carsuls.  Process  applications  of  the  technology  were   as  the  result  of  temperature  excursions  during  the  reviewed  in  an  article  in  Hydrocarbon  Engineering  in  October  20101  and  in  the  proceedings  of  the  Gas- made  during  the  primary  SWAP  reaction  appear  to  be  Tech  Conference  in  March  20112.  During  the  last  year,   carbon  polymers  containing  an  equal  ratio  of  carbon  SWAPSOL  has  developed  detailed  process  designs   and  sulfur  molecules.  About  half  of  the  expected  sulfur   production  is  normally  found  in  the  carsuls.  Sulfur  may   be  recovered  by  heating  the  carsuls:operational  advantages  to  implementing  the  SWAP.    Carsuls  +  heat  ==>  Carbon  polymer  +  Sulfur         5The  original  SWAP  reaction  can  proceed  spontane- An  additional  process  has  been  developed  for  the  ously  with  a  favorable  Gibbs  function: destruction  of  waste  hydrocarbons  with  hot  molten     2H2S  +  CO2  ==>  Sulfur  +  2H2O  +  carsuls       1       sulfur:    Waste  HC  +  Sulfur  ==>  H2S  +  Carsuls  +  Byproduct     6The  reaction  is  somewhat  exothermic  and  proceeds  in  the  temperature  range  of  70-200°C  at  ambient  to   The  waste  hydrocarbon  may  consist  of  waste  plastics,  moderate  pressures.  The  reaction  rate  decreases  sig- biomass,  motor  oil,  etc.  SWAPSOL  has  experimented   with  PVC,  polystyrene,  waste  motor  oil,  linseed  oil,  gases  such  as  methane,  propane  or  other  constitu-ents  of  natural  gas,  which  may  be  present  in  the  feed   depend  on  the  feed  material;  for  example,  PVC  de-stream  into  a  SWAP  reactor,  will  not  react  over  the   struction  will  produce  hydrogen  chloride.  The  hydro-catalyst,  making  the  SWAP  a  useful  technology  for  cleaning  sour  gases.  Methane  or  other  non-reactive   -gases  will  pass  through  the  reactor  as  diluents:   tively,  hydrogen  and  sulfur  may  be  recovered  from  the  CH4  +  2H2S  +  CO2  ==>  Sulfur  +  2H2O  +  carsuls  +  CH4     2 - ered  from  the  carsuls  via  reaction  5.Two  alternative  SWAP  reaction  paths  for  the  destruc- 1
  2. 2. During  the  last  two  years  we  have  met  with  several   was  assumed  to  be  3%  and  CO2  was  not  removed  potential  partners  and  have  learned  that  there  exists   2 S.    a  general  aversion  to  the  unknown:  we  have  been  told  many  times  that  there  is  a  limited  interest  in  the   In  order  to  have  a  valid  comparison  with  published   cost  data,  we  chose  identical  process  conditions  to  carbon  dioxide,  making  carsuls,  water  and  sulfur;   2 S  loading  of  5%  and  CO2  instead  our  domestic  discussion  partners  generally   at  3%  as  our  process  design  basis  for  a  commercial  prefer  Reaction  3,  the  reaction  path  with  air,  making  only  sulfur  and  water  as  products.  Early  this  year,  we  commissioned  a  detailed  process  design  and  cost   Cleaning  high-pressure  natural  gas  and  operat-analysis  for  that  process  variant,  covering  a  design   ing  an  air  oxidation  scheme  presented  two  reasons  for  a  typical  sour  gas  well  and  one  for  cleaning  land- for  pre-separating  the  sour  components  from  the   gas  well.  The  amine  stripper-regenerator  section  is  recovery  technology  performed  the  design  and  esti- readily  available  commercial  technology.  The  strip-mating  study.  We  will  be  performing  a  similar  detailed   per  tower  is  a  high-pressure  vessel,  while  the  amine  process  design  and  cost  study  of  the  hydrogen  from   regenerator  and  SWAP  reactor  operate  near  ambient   pressure,  at  a  level  to  maintain  water  as  a  liquid.  The   - etary  catalyst,  which  is  based  on  a  naturally  occur-The  recovery  of  hydrogen  and  sulfur  from  hydrogen   ring,  treated  mineral.  crude  oils,  any  sulfur  compounds  present  in  the  crude   we  considered  an  advanced  case  which  combines   the  amine  regenerator  and  SWAP  reactor  into  one   process  step.  Table  1  presents  a  cost  estimate  for  is  a  valuable  raw  material  generally  produced  on-site   both,  the  base  case  and  the  advanced  design.  Table  as  a  by-product  of  naphtha  reforming  or  via  steam   2  provides  comparative  cost  data  for  competing  reforming  of  natural  gas. sulfur  removal  processes  published  in  the  2004  US   4SWAPSOL  has  developed  a  catalytic  process  for  sulfur  at  a  temperature  range  between  about  150  -   Base   Advanced   Case Case450°C,  the  range  in  which  sulfur  exists  as  a  liquid.  The  process  is  endothermic  and  uses  ceramic  mem- Capital  Cost  (Million  $,  2008) 16.6 13.0branes  to  continuously  remove  hydrogen  from  the  re- Operating  Cost  ($  per  1000  scf)  the  driving  force  across  the  membrane;  alternatively,   Variable  Cost     0.27 0.03membrane  may  also  provide  the  necessary  driving   Direct  Costs   0.11 0.09force.  The  ceramic  membrane  consists  of  tubular  ele-ments,  making  process  scale  up  relatively  easy.  We   Overhead,  Taxes,   0.08 0.07 Insuranceare  currently  completing  the  design  and  construction  of  a  pilot  reactor  and  should  be  ready  for  pilot  plant                                  Cash  Cost 0.46 0.19Sour  Gas  Cleanup 0.11 0.09We  have  previously  reviewed  a  detailed  design  and   0.23 0.18economic  analysis  of  a  sour  gas  cleanup  process   Capital)based  on  SWAP  technology.3  Much  of  the  world’s  gas  reserves  are  sour;  estimates  indicate  that  up  to   Net  Treatment  Cost  ex  ROI 0.57 0.28study  estimated  the  cost  of  removing  sulfur  from  gas   Net  Treatment  Cost  with  ROI 0.80 0.46 Basis:  40  Million  scf/day,  1000  psi,  5%  H2SThe  work  considered  a  variety  of  commercial  sulfur   2 S  concentra- Table  1:  Cost  Estimates  for  Sulfur  Recovery   - 2  level   2
  3. 3. Sweet gas Acid Gas (H2S + CO2) Makeup water Rich Air Makeup amine water amine Lean Sour gas Liquid Reboiler Rich amine Lean amine Sulfur recovery Stripper Regenerator SWAP Reactor Figure 1: Simplified Process Flow Diagram Amine Stripper and SWAP Reactor 2004  Cost               ($  per  1000  scf) Claus  process  requires  a  high  temperature  furnace   followed  by  several  high  temperature  reactor  stages   Amine  Stripper  –  Aqueous  Redox   1.73 and  a  tail  gas  cleanup  unit.  Other  processes  use   Amine  Stripper  –  Claus  +  Tail  Gas   1.40 liquid-phase  catalytic  oxidation  reactors  requiring   Cleanup catalyst  separation  technology.  The  SWAP  catalyst   CrystaSulf 1.46 is  not  adversely  affected  by  the  presence  of  CO2,   whereas  in  a  Claus  furnace,  the  presence  of  CO2  may   CrystaSulf    -  DO 0.90 Basis:  40  Million  scf/day,  1000  psi,  5%  H2S liquid-phase  catalyst  systems  may  have  adverse                               Table  2:  Cost  Estimates  for  Competing  Sulfur   reactions  to  the  presence  of  CO2. Recovery  Technology We  have  recently  completed  a  process  design  and  It  should  be  noted  that  the  cost  estimate  for  the  SWAP  is  based  on  standard  estimating  procedures  employed  by  the  chemical  and  oil  industries  in  the  United  States.  Data  shown  from  the  USDOE  study   still  applicable  with  the  addition  of  a  blower/compres-does  not  provide  a  detailed  breakdown  as  shown  for   sor  at  the  gas  inlet;  the  stripper  now  operates  at  near  the  SWAP;  it  may  not  be  based  on  similar  estimating   ambient  pressure.  Table  3  presents  the  cost  basis  for  techniques.  Without  a  breakdown  of  capital  and  di-rect  operating  costs,  we  can  only  note  the  difference   S.  The  process  design  simula-in  the  year  for  which  the  estimate  is  valid.  What  is   2 tions  show  that  the  process  equipment  sizing  is  de- -cant  cost  advantages  over  competing  processes,   S  content  by  multiples  especially  since  the  competing  cost  data  needs  to   2 2 requirements.  Analysis  of  the  design  details  reveals   that  some  equipment  is  oversized,  most  likely  caused   by  the  fact  that  commercial  estimating  routines  are  standard  -  the  Claus  process.  With  the  advanced   generally  developed  for  large-scale  plants  rather  than  SWAP  process,  the  potential  advantage  increases  to  70%.  In  addition,  there  are  several  major  operational   this  analysis,  cost  data  shown  in  Table  3  is  very  con- servative  and  probably  overstated.    bed  reactor  is  well  known  in  the  industry  and  easily  controlled,  especially  at  relatively  low  temperatures   3
  4. 4. Base  Case Laboratory  scale  development  of  the  various  SWAP- Capital  Cost  (Million  $,  2008) 4.9 SOL  processes  is  nearing  completion,  and  the   company  is  scheduled  to  begin  pilot  plant  studies   Operating  Cost  ($  per  1000  scf)   in  the  near  future.  Our  next  process  design  and  cost   2 S  pro- Variable  Cost 0.08 Direct  Costs 0.28 reductions  compared  to  producing  hydrogen  via  the   Overhead,  Taxes,  Insurance 0.27 traditional  steam  reforming.  As  noted  above,  we  are   completing  the  design  and  construction  of  a  mem- Cash  Cost 0.63 brane  hydrogen  reactor  by  year-end  and  hope  to   begin  pilot  plant  studies  early  next  year.  This  should   0.33 put  us  in  a  position  to  plan  for  a  commercial  applica- 0.67 application  of  a  SWAP  sour  gas  cleanup  process  is   Capital) - tion  with  existing  on-site  processes  will  be  needed.   Net  Treatment  Cost  ex  ROI 0.96 SWAPSOL  has  received  one  patent  on  its  processes   and  has  several  others  pending.  The  company   Net  Treatment  Cost  with  ROI 1.63 intends  to  enter  into  joint  venture  and/or  joint  devel- Basis:  4  million  scf/day,  1%  H2S opment  partnerships  for  different  SWAP  applications                                       in  the  petroleum,  chemical  and  independent  natural   gas  processing  sectors.  The  SWAP  has  the  potential   energy  generation  industries,  and  may  reduce  pro- - tional  technologies.    not  found  a  comprehensive  study  analogous  to  the  deep  well  gas  design  case;  the  data  we  have  found   1  Koch,  W.,  et.al.,  A  Spontaneous  Swap,  Hydrocarbon  has  been  published  by  process  vendors  without   Engineering  the  details  necessary  for  a  reliable  comparison.  In   2  Koch,  W.,  et.al.,   ,  Amster-addition,  most  published  data  lists  the  processing   dam,  March  2011.cost  per  ton  of  sulfur,  a  number  which  favors  high  sulfur  loading  cases  as  discussed  above.  We  have   3  Koch,  W.,  et.al.,  From  Mean  to  Clean,  Hydrocarbon  Engi-located  an  installation  permit  application  for  a  land- neering 4 -based  on  vendor  estimates.5  A  paper  presented  by   grading  Final  Report 2004.gas  unit  in  Warren,  PA,  is  also  lacking  the  neces-sary  details.6  When  we  add  costs  to  the  Merichem     5estimate  for  the  usual  overheads  listed  in  Tables  1   Application  No.  1270-2and  3  and  adjust  the  capital  requirements  for  2008,   pdf)the  costs  shown  in  Table  3  are  similar  to  the  Warren  installation.  While  we  have  not  performed  a  detailed   6  J.  Carlton,  et.  al.,  T Electricityexpect  reductions  in  costs  similar  to  what  is  shown   technical_papers/index.php)in  Table  1.  Of  course,  all  the  additional  advantages  gas  treating. Sulphur  2011,  November  2011,  Houston  TX. www.swapsol.com/business@swapsol.com 4

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