Method and system for gtl production in fpso

Patent metadata

Field	Value
Publication number	US-2016168489-A1
Application number	US-201414907255-A
Country	US
Kind code	A1
Filing date	Jul 24, 2014
Priority date	Jul 25, 2013
Publication date	Jun 16, 2016
Grant date	—

Abstract

Disclosed herein are a gas-to-liquid (GTL) producing method and system for floating production, storage, and offloading (FPSO). The gas-to-liquid (GTL) producing method for FPSO according to the present invention, which is to produce GTL in FPSO, may include:
1) a pre-treating step of pre-treating natural gas produced at an offshore gas field; 2) a reforming step of reacting the pre-treated natural gas in a presence of a catalyst to produce syngas containing hydrogen and carbon monoxide; 3) a synthesis step of supplying the syngas to a Fischer-Tropsch reactor and reacting the syngas to produce liquid hydrocarbon; and 4) an upgrading step of separating the liquid hydrocarbon into gas, naphtha, and syncrude and supplying hydrogen to hydrofinish the liquid hydrocarbon.

First claim

1 . A gas-to-liquid (GTL) producing method for floating production, storage, and offloading (FPSO) comprising:
1) a pre-treating step of pre-treating natural gas produced at an offshore gas field; 2) a reforming step of reacting the pre-treated natural gas in a presence of a catalyst to produce syngas containing hydrogen and carbon monoxide; 3) a synthesis step of supplying the syngas to a Fischer-Tropsch reactor and reacting the syngas to produce liquid hydrocarbon; and 4) an upgrading step of separating the liquid hydrocarbon into gas, naphtha, and syncrude and supplying hydrogen to hydrofinish the liquid hydrocarbon.

2 . The GTL producing method for FPSO of claim 1 , wherein the upgrading step includes:
1) a separation step of separating the liquid hydrocarbon produced in the synthesis step into gas having 1 to 4 carbon atoms, naphtha, and syncrude; and 2) a hydrofinishing step of supplying hydrogen to the separated naphtha to saturate olefin.

3 . The GTL producing method for FPSO of claim 2 , wherein a condensate produced in the hydrofinishing step is separated to thereby be mixed with the syncrude separated in the separation step, and
gum formation and polymerization of olefin contained in at least one of the naphtha and syncrude during storage and transportation are prevented through the hydrofinishing step.

4 . The GTL producing method for FPSO of claim 2 , wherein the gas having 1 to 4 carbon atoms separated in the separation step is supplied as fuel for the FPSO.

5 . The GTL producing method for FPSO of claim 2 , wherein the hydrofinishing step is performed at a relatively low temperature of 250 to 290° C. and a relatively low pressure of 15 to 30 bars.

6 . The GTL producing method for FPSO of claim 1 , further comprising a conditioning step of conditioning the syngas produced after the reforming in the reforming step before supplying the syngas to the Fischer-Tropsch reactor of the synthesis step,
wherein hydrogen generated during the conditioning is at least partially supplied to the upgrading step.

7 . The GTL producing method for FPSO of claim 6 , wherein the reforming step is performed in a steam CO 2 reformer (SCR) supplying steam and carbon dioxide to the natural gas and reacting the natural gas in the presence of the catalyst, and
the Fischer-Tropsch reactor in the synthesis step is a slurry phase reactor (SPR).

8 . The GTL producing method for FPSO of claim 7 , wherein the steam CO 2 reformer is a compact reformer.

9 . The GTL producing method for FPSO of claim 8 , wherein carbon dioxide participates in a production reaction of the syngas as a reverse reaction of a water gas shift reaction in the compact reformer.

10 . The GTL producing method for FPSO of claim 7 , wherein the syngas unreacted in the slurry phase reactor is recovered to thereby be re-supplied to the synthesis step.

11 . The GTL producing method for FPSO of claim 1 , wherein steam generated in the synthesis step and the reforming step is supplied to a steam turbine power generator provided in the FPSO, thereby generating power.

12 . The GTL producing method for FPSO of claim 6 , wherein in the conditioning step, H 2 O is separated in multiple steps from the syngas produced after the reforming, and hydrogen is separated so as to satisfy requirement conditions in the Fischer-Tropsch reactor, but
H 2 is recovered so that a ratio(SN) of H 2 /CO supplied to the Fischer-Tropsch reactor satisfies 1 to 2.5.

13 . The GTL producing method for FPSO of claim 12 , wherein hydrogen recovered in the conditioning step is at least partially supplied as fuel in the reforming step.

14 . The GTL producing method for FPSO of claim 13 , wherein the reforming step is performed in a steam methane reformer (SMR) reacting the natural gas with hydrogen supplied in the conditioning step.

15 . A GTL producing system for FPSO comprising:
a pre-treating unit in which pre-treatment including desulfurization is performed on natural gas produced at an offshore gas field; a reformer receiving the natural gas from the pre-treating unit to produce syngas containing hydrogen and carbon monoxide; a Fischer-Tropsch reactor receiving the syngas from the reformer to produce liquid hydrocarbon; and an upgrading unit receiving hydrogen and the liquid hydrocarbon from the Fischer-Tropsch reactor and hydrofinishing the liquid hydrocarbon to produce naphtha and syncrude.

16 . The GTL producing system for FPSO of claim 15 , further comprising a conditioning unit conditioning the syngas produced in the reformer before the syngas is supplied to the Fischer-Tropsch reactor,
wherein hydrogen produced in the conditioning unit is supplied to the upgrading unit.

17 . The GTL producing system for FPSO of claim 15 , wherein the reformer is a steam CO 2 reformer (SCR) receiving the natural gas to supply steam and carbon dioxide, and reacting the natural gas in a presence of a catalyst to produce the syngas containing hydrogen and carbon monoxide, and
the Fischer-Tropsch reactor is a slurry phase reactor (SPR).

18 . The GTL producing system for FPSO of claim 15 , wherein the upgrading unit supplies hydrogen to the liquid hydrocarbon and hydrofinishes the liquid hydrocarbon to saturate olefin contained in at least one of the naphtha and syncrude, thereby preventing gum formation and polymerization of the olefin during storing and transporting at least one of the naphtha and syncrude.

19 . The GTL producing system for FPSO of claim 15 , wherein compounds having 1 to 4 carbon atoms, produced in the Fischer-Tropsch reactor and the upgrading unit are supplied as fuel of a complex power generation system of the FPSO.

20 . The GTL producing system for FPSO of claim 16 , wherein the conditioning unit includes:
first to third separators separating H 2 O from the syngas in multiple steps; and an extractor recovering hydrogen from hydrogen and carbon monoxide separated in the third separator.

21 . The GTL producing system for FPSO of claim 20 , wherein the reformer is a steam methane reformer (SMR) reforming the pre-treated natural gas and H 2 O and CO 2 into combustion gas and hydrogen, and CO and H 2 O using hydrogen recovered in the extractor.

22 . The GTL producing system for FPSO of claim 20 , wherein the extractor is provided with a membrane capable of adjusting an amount of passed hydrogen.

23 . The GTL producing system for FPSO of claim 22 , wherein hydrogen recovered by the membrane is supplied to the reformer and the upgrading unit.

24 . The GTL producing system for FPSO of claim 22 , wherein a ratio(SN) of H 2 /CO supplied from the conditioning unit to the Fischer-Tropsch reactor is 1 to 2.5.

Assignees

• Daewoo Ship Building & Marine Engineering Co Ltd
• Daewoo Shipbuilding & Marine

Inventors

• Kwon Hyuk
• Kim Hyun Jin
• Kim Won Seok

Classifications

• C10G45/02 Primary

  to eliminate hetero atoms without changing the skeleton of the hydrocarbon involved and without cracking into lower boiling hydrocarbons; Hydrofinishing · CPC title

• C01B2203/0227

  containing a catalytic reforming step · CPC title

• C10G65/16 Primary

  including only refining steps · CPC title

• C01B2203/062

  Hydrocarbon production, e.g. Fischer-Tropsch process · CPC title

• C01B3/38

  using catalysts · CPC title