552 
OBTAINING  OIL  FROM  BITUMINOUS  COAL. 
quantity  ;  and  although  some  of  the  coals  last  described  contain 
a  large  amount  of  earthy  matters,  those  matters  do  not  interfere 
materially  with  the  performance  of  this  process.  To  obtain  para- 
fine  oil  from  coals,  the  following  is  the  method  of  procedure  : — 
The  coals  are  to  be  broken  into  small  pieces,  and  are  then  to  be 
put  into  a  common  gas  retort,  to  which  is  attached  a  worm  pipe 
passing  through  a  refrigerator,  and  kept  at  a  temperature  of 
about  55°  Fahr.  by  a  stream  of  cold  water.  The  temperature 
of  the  refrigerator  should  not  be  made  too  low,  lest  the  product 
of  the  distillation  should  congeal  and  stop  up  the  pipe.  The 
retort  being  closed  in  the  usual  manner,  is  then  to  be  gradually 
heated  up  to  a  low  red  heat,  at  which  it  is  to  be  kept  until  vola- 
tile products  cease  to  come  off.  Care  must  be  taken  to  keep  the 
temperature  of  the  retort  from  rising  above  that  of  a  low  red 
heat,  so  as  to  prevent  as  much  as  possible  the  desired  products 
of  the  process  being  converted  into  permanent  gas.  The  coke 
or  residue  may  then  be  withdrawn  from  the  retort,  which,  being 
allowed  to  cool  down  below  a  visible  red  heat  (to  prevent  waste 
of  the  fresh  material  to  be  introduced,)  may  be  again  charged 
with  a  quantity  of  coals  to  be  treated  in  the  like  manner.  The 
crude  parafine  oil  distilled  or  driven  off  from  the  coals  as  a  vapor, 
will  be  condensed  into  a  liquid  in  passing  through  the  cold  worm- 
pipe,  from  which  it  will  fall  into  a  vessel  which  must  be  provided 
to  receive  it.  Instead  of  obtaining  the  whole  of  the  parafine  oil 
by  distillation,  a  portion  of  it  may,  in  some  cases,  if  thought 
desirable,  be  run  from  the  retort  (through  an  opening  and  a  pipe 
provided  in  the  anterior  and  lower  part  of  the  retort  for  that 
purpose)  after  it  has  separated  from  the  coal  and  assumed  a 
liquid  form.  The  patentee  prefers,  however,  in  every  case  to 
distil  or  drive  off  the  whole  of  the  parafine  oil  to  be  obtained 
from  the  coal.  The  production  of  the  desired  products  from  a 
charge  of  coals  in  a  retort  will  be  known  to  be  finished  by  the 
liquid  ceasing  to  run  from  the  worm.  The  crude  product  of  this 
process  is  an  oil  containing  parafine,  which  the  patentee  calls 
parafine  oil.  This  oil  will  sometimes,  upon  cooling  to  a  tempera- 
ture of  about  40°  Fahr.,  deposit  parafine.  Other  arrangements 
of  apparatus  may  be  used  for  subjecting  coals  to  the  process  for 
obtaining  parafine  oil  therefrom,  but  that  above  mentioned  is 
preferred  as  being  well  known  and  easily  managed.    But  in 
