Note: Descriptions are shown in the official language in which they were submitted.
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WO ~0/~+7832 Ref : I5-41--Ot~-O1 /IN
PT/DEOOIUO~+12
Process for extraction of methane hydrate on thQ sea bed.
Tho invention refers to a process for extraction of methane
hydlcate an the sea bed.
On the sea bed grayish~white lumps exist, the sa called
dirty i.ce. '!'his insignificant material con be 5alutian of
ull er,~rc,~y ~ixuVlWtls.
It deals with a methane hydrate, a substat,tr~ out ofi water
and metltcsne. Under high prrissurn nn~t l.r~w xem~rRrnt;rtrs~ wator
molecules have deposited in a solid latice band around
gaseous methane mnlec;ules crud have practically encased
these.
Whert the structure of this "icegas" is dissolved through
heat and/or prcssuxe loss the gop escapes and it is on the
other hand as important enexgy carrier correspondingly
useful. Methane hydrate is also denoted as frozen methane.
Alone an tire secr Led in arcs of east-and west coast of USA,
one estimates the rcsez~ve of 11 billiard m9 methane gas,
the eighty thousand tirrre of world wide known natural gas
deposits. 'this energy quantity exceeds all, whir.h is known
till no~r_
When vnl.y 1'~ of this mathanc~ reserve was mode ncc:essible,
the gas resourca$ of USA would ae more than doubled. With
it the U.S.A. would cover their gas rQquirement no mare
only for &0 years, but already ~khen for RO years.
The problematic nature exists till now in extraction and
lifting of this frazc~n gas containing hydrate quantity.
..2.
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The assignment lies therefore at the baser of the invention,
to develop an economic process for extraction of solid
mothc~no hydrata out of the sea.
'this assignment is salved as per invention through a
process as per the faatures of present patrtnt elctim 1.
As per invention, it is proposed, to lift the solid rnerthane
hydrate to the surface taking basis of mammoth pump
pri.ncfple in pipe lines, which depending on volume of
hydrata quantity bQlow an the sea hed scan hnve n di,nmetsrr
upto several meters. At the deepest tube position below in
area on inlet nozzles ~areferabl.y concentric nozzles can be
brought in, which depending an the depth of rnc~thane hydrate
JGNosit4~i vn tha saa bad c~ern bo ~mpingod with aompx'oscad
uir und~sr a pressure upta sevaxal 100 bore. On g~cound of
mammpt~t pump principle, in the tube s~ strong flaw dev,alops
from below to upwc~r d, in which local ~.edmathane hydrate
lumps frnm surrounding of tube end below an the sea bed are
carried aver. There~.n in upward flow of solid mathane
hydride us well as tltiat~gh ths3 pressure relief cts also
thxou~h the rise of temperature the methane hydrate is
melted and thereby gaseous methane i$ released, which .Leads
to a further intensification of lifting in delivery tube.
T~h~a melted methane is then callecfied in upper area of
delivery tube in corresponding internal chambers and then
can be supplied for furthar utili~atian,
In addition to compressed air or also in place of
Compressed air, far ge~netratian of desired lifting in
delivery ~tut~e also a dense medium Liquid with suitable
specific density c:an be Applied.
Functi.Gnnlly the dnns~r ntr~rli.unt l.icir.rid aftbr passing of
delivery to be can agairt be separated in suitable separating
...3.
CA 02328859 2000-10-13
_ ~ _
oqu,ifymants vut of sea watar aced in cytla can bo pumped
renewed to lower part ofi delivcrxy tube.
Through it, that as per a further feature of process
according to invention the cross section of d~rlivery tube
from bottom to top ,is expandczd, the additional gas quantity
generating through the melting of methane hydrate can be
takcsn into considcratian. In addi~ti.on xt Gomos, that
through a such measure the flow speed in delivery tube and
with it the residence timt3 ref solid methane Inydrate intube
can be influenced. As far example, it is possib3.e through
it to maintain a constant fil.ow speed in delivery tube.
In a further design of process, it is prUposerJ~ that at trip
at averflaw ..f delivery tuba deverlaped cps me~mmt~th pump a
ga;~ ac~llecting containor xN pravidcd and a ua~ter~-dense
medium--separation is carried out, so that, r~s desi.rt~d the
ggs can he c311e ated. Aftar separatic~rr ~ofi water tend dense
medium, the d~:nse medium can again be pressed through pumps
to downward to inlet of mammoth pump system.
Fvz' c~uir:fc.er hecttxrtc~ of sc~lic! ~nuLW ytYe i'ydf'tita arld with is
also for acceleration of mGthAne gas releaso in d~livery
tulae, cornprassed air, anchor dense mt~dium-liquid can be
ar~ditianally l3oatcrd bs~tore their input as per a further
faature of invention.
A farther essential advantage of process cas per inventl.an
is to be seen titc:.rcin thryt, st~ou~Ld trw ocac~si.on arise,
tiea~in rock contents irf methane hydrate tE'ren, Ugain slump
to d~a~.~nward, slowly. fln ground of specifically adjusted flow
conditions in tube, when the methane hydrate has melted and
the gas has escaped and fill up again partly the free space
at sdu bed out of which tho solid methnncz hydrates was
extracted.
...4.
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The process is net limited on the appxicatian an tile sea or
rather sea bed, but abviausly cc~n also be' input as pex~
invantian on solid ground areas. !Here as for example, it
can lee necessary to work with an insulated tube ae~c~ir~~rt
coldness and with spcc~.fica~.ly prtpaxad water, in order to
extract frozen methane hydrate out o~F several 100 meters
depth. In the enclose:d~ draai~rrg-i~ ~-epresen~t-~~dw ;. . . . . _ ..._
with (1) Sea or rather water
with (2) Sc~a bed, far axaEaple 800m. deep
with (3) t7elivery tuba with approximately 5m. diameter,
which widens to up~ws~rds.
with (4) Concentric shaped nozzles which forces the
compressed pi.r in the carrying medium.
The compressed stir can be preheated a~ for
example as hat air and is again partly aQQled
through the expansion. Tho high temperature
however contributes to it that the solid methane
hydrate molts quicker.
with (5) tZising methane hydrate pebbles.
with (b) Out of rising gas hydrate pebbles x~~l.easing
ma~thana.
with (7~ Th~ methane coilectin~ container.
with (8) The water dense medium separation.
with (9) The compressed crir-dense medium mixture.
wa.th(1~) Thc: compressor unit.
with(li) 'The pres~su.re vesEel.
On the sea bed (2) meehanicc~l equiprnonts arQ provided,
which .introduce the frozQft ice by means of gripping davic$
tar skimmer at the entry of the tube and transfer inward tc~
tht~ system delivery tube.
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' Patent claims.
