BACKGROUND OF THE INVENTION

[0001] Field of the Invention

[0002] The present invention relates to production of methanol and other synthesis gas derived products. Specifically, the present invention relates to the optimization of the stoichiometric ratio of the synthesis gas such that only a single shift section is required in the operation.

[0003] Description of the Related Art

[0004] Gasification processes and many natural gas reforming processes produce a synthesis gas containing hydrogen, carbon monoxide, carbon dioxide and other components. This synthesis gas can be used to make methanol and other synthesis gas derived products, such as ammonia and synthetic natural gas. Each of these synthesis gas derived products has a different ideal stoichiometric ratio of the synthesis gas at which each respective product is produced.

[0005] The present invention improves upon the production of synthesis gas derived products by producing a synthesis gas with a stoichiometric ratio to produce multiple synthesis gas derived products in a single facility.

BRIEF SUMMARY OF THE INVENTION

[0006] According to one embodiment of the invention, a method for producing at least two synthesis gas derived products includes a step of selecting a stoichiometric ratio for synthesis gas above the ratio normally required for a first synthesis gas derived product and below the ratio normally required for a second synthesis gas derived product. The method also includes a step of producing the first synthesis gas derived product and a step of directing excess synthesis gas product to production of the second synthesis gas derived product. The method further includes a step of producing the second synthesis gas derived product. The

stoichiometric ratio for synthesis gas is chosen such that the excess components makes up for a shortage of components needed for the production of the second synthesis gas derived product. [0007] In another embodiment of the invention, the selecting step also includes selecting the stoichiometric ratio for synthesis gas below a ratio normally required for a third synthesis gas derived product. The method further comprises steps of directing a portion of the excess synthesis gas product to production of a third synthesis gas derived product and producing the third synthesis gas. The stoichiometric ratio for the synthesis gas is chosen such that the excess components also make up for a shortage of components needed for the production of the third synthesis gas derived product.

[0008] According to another embodiment of the present invention, a system for producing at least two synthesis gas derived products includes a first shift section to produce a synthesis gas with a first stoichiometric ratio above a stoichiometric ratio required to produce a first synthesis gas derived product and below a stoichiometric ratio required to produce a second synthesis gas derived product. The system also includes a first apparatus to produce the first synthesis gas derived product and a second apparatus to produce the second synthesis gas derived product. The system further includes a first channel to direct excess synthesis gas components from the first apparatus to the second apparatus. The first stoichiometric ratio produced by the first shift section is such that the excess synthesis gas components make up for a shortage of components needed to produce the second synthesis gas derived product.

[0009] In an embodiment of the present invention, the system includes a third apparatus to produce a third synthesis gas derived product and a second channel to direct a portion of the excess synthesis gas components to the third apparatus. The first stoichiometric ratio produced by the first shift section is such that the excess synthesis gas components also make up for a shortage of components needed to produce the third synthesis gas component. The second channel may direct the portion of excess synthesis gas components from the first channel to the third apparatus.

[0010] In an embodiment of the present invention, the first synthesis gas derived product is methanol, the second synthesis gas derived product is ammonia and the third synthesis gas derived product is synthetic natural gas.

[0011] The above and other aspects and embodiments are described below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate various embodiments of the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention. In the drawings, like reference numbers indicate identical or functionally similar elements.

[0013] FIG. 1 illustrates a block diagram of a system for producing multiple synthesis gas derived products from a single synthesis gas shift according to an embodiment of the present invention.

[0014] FIG. 2 illustrates a block diagram of a system for producing multiple synthesis gas derived products from a single synthesis gas shift according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0015] Fig. 1 illustrates a block diagram 100 of a system for producing multiple synthesis gas derived products from a single synthesis gas shift according to an embodiment of the present invention. The system depicted in block diagram 100 produces methanol and ammonia. The system includes a shift section 102 for producing a synthesis gas. The shift section 102 may be a catalyst bed. The synthesis gas may be Rectisol or any other suitable synthesis gas, and contain hydrogen, carbon monoxide, carbon dioxide, water and other components. The shift section 102 produces a synthesis gas with a stoichiometric ratio which is above the stoichiometric ratio required normally for the production of methanol and below the stoichiometric ratio required normally for the production of ammonia. A channel 1400-4.0 directs the stream of synthesis gas from the shift section 102 to a split in which a methanol channel 4950-101 directs a portion of the synthesis gas stream to a methanol synthesis system 104 and a secondary products channel 1400-4.101 directs the remaining synthesis gas stream to the systems for producing any other synthesis gas derived products, such as ammonia or synthetic natural gas. The methanol synthesis system 104 produces methanol which is directed to a methanol to gasoline system 106 by a channel 4950-503. The methanol to gasoline system 106 may produce gasoline product and liquefied petroleum gasoline. [0016] The methanol synthesis system 104 also produces excess synthesis gas components because the stoichiometric ratio of the synthesis gas is above the ratio required normally for production of methanol. For example, the synthesis gas may have excess hydrogen as well as an excess of other components, e.g., carbon monoxide and carbon dioxide. A portion of the excess synthesis gas is directed to a channel 4950-112 that is combined with the secondary products channel 1400-4.101 to form a combined secondary products channel 1400-4.102. As shown in Fig. 1, the entirety of the stream of the combined secondary products channel 1400- 4.102 may be directed to the production of a single other synthesis gas derived product. For example, the entire steam from the combined secondary products channel 4950-4.102 may be directed to the production of ammonia. The ammonia production channel 1400-4.104 directs the stream to the ammonia plant 110, which produces ammonia. In this embodiment, the stoichiometric ratio of the synthesis gas produced by the shift section 102 is chosen such that the excess components from the methanol synthesis system 104 make up for the shortage of components in the synthesis gas required to produce ammonia.

[0017] The system 100 may also include a pressure swing adsorption system 108 and an air separation unit 114. A portion of the excess synthesis gas components from the methanol synthesis system may be directed to the pressure swing adsorption system 108 by a channel 4950-104. The pressure swing adsorption system 108 produces hydrogen which may be directed to other units in the system 100. For example, the hydrogen may be directed to the methanol to gasoline system 106 and the ammonia plant 110 to assist in the production of gasoline product and ammonia. The pressure swing adsorption system 108 may also produce a fuel export containing methane, hydrogen, carbon monoxide, carbon dioxide and other components. The air separation unit 114 separates air into its primary components, such as nitrogen and oxygen. The nitrogen and oxygen may then be directed to other parts of the system 100, such as the ammonia plant 110 to assist in production of ammonia and the methanol synthesis system 104 to assist in production of methanol.

[0018] Table 1, below, details the composition of the stream (e.g., synthesis gas, ammonia, methanol, etc.) carried by the channels in system 100. Table 1

Table 1 cont.

Table 1 cont.

[0019] Fig. 2 illustrates a block diagram for a system 200 producing multiple synthesis gas derived products from a single synthesis gas shift according to another embodiment of the present invention. In system 200, a synthetic natural gas unit 1 12 is included to produce a sythentic natural gas. The system 200 is the same as the system 100 described above except the combined secondary products channel 1400-4.102 delivers a portion of the synthesis gas to the synthetic natural gas unit 1 12 via a channel 1400-4.103. The system 200 would direct the excess synthesis gas components to the secondary products channel 1400-4.101 to form a combined secondary products channel 1400-4.102, similar to system 100 described above. In this embodiment, the stoichiometric ratio of the synthesis gas produced by the shift section 102 is chosen such that the excess components from the methanol synthesis system 104 make up for the shortage of components in the synthesis gas required to produce ammonia and synthetic natural gas.

[0020] Table 2, below, details the composition of the product (e.g., synthesis gas, ammonia, methanol, etc.) carried by the channels in system 100.

Table 2

Table 2 cont.

Stream Name 4950-101 4950-102 4950 103 4950-112 4350-104 4950-105 4950-108

HYiSSOSSX

Stream DgscrspSkm t TOROSEN HTOSOGSN

FROM TO EUf TO WST

P MT TO SHS + NH3

5S.4S% 5943% 59.49% 4.77% 8.80% 59.49%

Tsmpsratee f'Fj 75 m 149 149 149 149 288

Pressure [osisi] 394 394 394 394 394 360 81

Phsse VAPOR VAPOR VAPOR VAPOR VAPOR VAPO VAPOR

Molar Ftew [tom8¾¾j 29,910.82 10,158.32 6,004.07 3.820.89 333.37 0.00 203.79

Mass Row JST h] 160 6 34,8 20 0 128 1.1 0.0 0.2

Vapsf Flow [ Mscf ] it.35 3.85 2.28 1.4S 0.13 0,00 008

Me! Weight 10.74 8.89 S.S9 S.69 6.S9 2.04 2.04

Composition i«ts3%)

Watesr - 0.24 0.24 024 0,24 - -

Hydrogen 58.70 81.19 81.19 81.1S 81.13 99.84 99.94

Carbon erwsfje 22.30 3.78 3.78 3.78 3,78 - - eastern DiOJtitSe 0.S6 4.0? 4.07 4.07 4,8? - -

Nitrogen 8.08 0,50 0.S8 o.se 0 50 0.01 0.01

0.20 1.S7 1,5? 1.57 1.5? 0.04 0.84

Methane 17.96 8 04 8.64 8 64 8 84 -

Ethane 0.11 0,02 0.02 0.02 002 - -

Methar»l - - - - - -

Lights - - - - - - -

Heavies - - - - - - -

Oxygen - - - - -

F8s¾v Rate, !iHSCtei f

Water - 24.38 14.41 9.17 0,843 - -

Hydrogen 17,555.78 9,248.72 4.874.22 3,101.87 270,63 0.00 203 S§

Carbon McncKide 8,669.40 383.95 226 93 144.42 1260 -

Carbon DSosde 197.39 413.4S 244 34 155.49 13.57 - - f-iiroQen 23 93 5079 30.02 19,10 1.87 000 0.02

Afgsss 53.82 159.47 94.25 59 88 5.23 0.00 0,08 etrtsne 5,371 41 877.59 518.70 338.88 28.80 - -

Ethane 32.90 2.83 1.20 0,78 0.07 - -

MetssrtS; - - - - - - -

LsgWs - - - - - - -

Heavies - - - - - - -

Oxygen - - - - - - -

Table 2 cont.

[0021] While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments.