Abstract
There is disclosed a near shore floating vessel for large scale production of methanol (capable of producing at least 4000 tons per 24-hour day) from natural gas (methane) and for export shipment. More specifically, the near shore floating vessel obtains methane from an on-shore methane stream or pipeline. The disclosed near-shore floating vessel provides several environmental and commercial advantages to move methane export to a near shore instead of an on-shore location.
Claims
1-4. (canceled)
5. A near shore floating methanol conversion system comprising a deck and a hull having a hold, wherein the deck comprises: (a) an access port to a natural gas line to supply natural gas to the floating near shore methanol conversion system; (b) a reformer system to convert natural gas to a syngas; (c) a methanol converter and distillation system to form methanol by oxidation of the syngas; and a holding tank within a hull of the floating methanol conversion system.
6. The near shore floating methanol conversion system of claim 5, further comprising a mooring system having a natural gas termination line from an on-shore location.
7. The near shore floating methanol conversion system of claim 6, wherein the mooring further comprises access to electrical power.
8. The near shore floating methanol conversion system of claim 5, wherein the reformer system comprises a steam reformer (SMR) or a SMR connected to an ATR (autothermal reformer) to produce syngas from input of natural gas and steam to the steam reformer and oxygen to the ATR.
9. The near shore floating methanol conversion system of claim 8, wherein the oxygen input to the ATR comprises an ASU (air separation unit) air to generate pure oxygen and avoid nitrogen input into the reformer system.
Description
BRIEF DESCRIPTION OF THE FIGURES
[0023] FIG. 1 shows a schematic of an on-deck methanol production system and their connections of the components, comprising inputs of natural gas, steam and oxygen and has GHR (catalyst is loaded in the tube) (1), an ATR (2), a Heat recovery system (3), an Air separation Unit (ASU) (4), a Boiler (5), a Syngas compressor unit (6), a Methanol synthesis unit (7), and a Methanol distillation system (8) all connected as shown in FIG. 1.
[0024] FIG. 2 shows a diagram of a preferred methanol from methane/natural gas conversion system to can produce 5000 tons per day of methanol on a ship substantially the size of a New Panamax or Suezmax tanker.
[0025] FIG. 3 is a labelled depiction of a floating methanol conversion ship moored to a yoke with a natural gas line that shows the configuration of the FIGS. 1 and 2 components on the deck of the ship.
DETAILED DESCRIPTION
Methanol Production Process
[0026] A floating methanol conversion system preferably uses a dual reformer system, such as that shown in FIG. 1 schematically and in FIG. 2 in a pictorial presentation. The dual reformer uses a steam reformer (labeled GHR for gas heated reforming) with heat exchangers to transmit heat to an ATR (autothermal reformer). The inputs to the dual reformer (FIGS. 1 and 2) is natural gas (methane with SH added so that there will be an odor to detect it), steam produced by a boiler and oxygen to the ATR component of the dual reformer system. The oxygen gas is preferably substantially pure oxygen or an oxygen-enriched air. The amount of oxygen use is preferably provides an oxygen:carbon molar ratio is the range of 0.5 to 0.75 to 1. Steam is at a carbon ratio between 0.6 and 2. The syngas produced is hot and the heat is recovered to utilize back in the reformer to reduce heat needed to run the reforming reaction and minimize CO.sub.2 emissions from burning natural gas to produce heat. Moreover, the key to this example of a dual reformer system is that it allows for greater output capacity while minimizing surface area foot print on a limited deck surface for a floating methanol system.
[0027] Steam is provided directly to the combustion zone of the steam reformer. The methane in the feed gas is partially oxidized by oxygen from the oxygen enriched stream in the ATR or autothermal reformer. The partial oxidation reactions (with substantially pure O.sub.2) are exothermic so the partial oxidation reactions raise the temperature of the reformed gas to 1200 to 1500 C.
[0028] This hot syngas from the ATR reformer is moved a short distance on the deck of the floating ship (FIG. 3) to both a distillation column and a syngas compressor to move both syngas and heat to be utilized without requiring additional heat sources from burning natural gas (and creating CO.sub.2 emissions). This process is in contrast to a much lower capacity U.S. Pat. No. 7,799,834 which uses tall distillation columns that limit the capacity of its floating system and uses air (with majority inert nitrogen) to significantly limit the capacity of the floating vessel to produce methanol to converting gas from well heads to prevent flaring rather than providing a means for exporting natural gas (that competes with LNG (liquified natural gas) export systems).
[0029] FIG. 3 is a picture of an exemplary floating methanol production ship for commercial quantity methanol production of from about 5000 tons per day to a larger version of about 10,000 tons per day. The components shown in FIG. 1 in a diagram are placed on the deck of the disclosed methanol converter ship. The hold tank is not shown but located underneath the deck to hold liquid methanol output that is either moved directly with the disclosed ship or off-loaded to a tanker ship in a sea-to-sea transfer of the liquid methanol. The ASU cold box produces pure oxygen to feed into the reformers. The boiler produces steam to feed into the reformers. The overall size of the ship shown in FIG. 3 is substantially similar to a Panamax tanker that can fit through the Panama Canal and is capable of producing about 5000 tons of methanol per day (24 hours) with one natural gas line feeding the ship via a mooring shown in FIG. 3. FIG. 3 also shows an optional power generator to allow for methanol production without power being supplied through the mooring. Therefore, the disclosed methanol ship can produce export quantities (about 5000 to about 10,000 tons per day of methanol with one natural gas lines or two natural gas lines) as a floating near shore production ship for export quantities of methanol.
