KR-102962914-B1 - METHOD AND SYSTEM FOR DECARBONIZED LNG PRODUCTION

KR102962914B1KR 102962914 B1KR102962914 B1KR 102962914B1KR-102962914-B1

Abstract

By integrating natural gas liquefaction, hydrogen production, and power generation systems, CO2 capture is increased and overall plant efficiency is improved. Methane endflash is primarily transferred to the hydrogen production system, which generates hydrogen and CO2. The CO2 can be captured or utilized beneficially. At least a portion of the generated hydrogen is used to fuel gas turbines during power generation, which in turn powers the refrigeration compressors of the natural gas liquefaction system in the form of mechanical work or electricity.

Inventors

웨이스트 안네마리 오트
비어드 제레미 디.
그라함 데이비드 로스
팔라마라 존 유진
로버츠 마크 줄리안
베스코빅 데잔

Assignees

하니웰 엘엔지 엘엘씨

Dates

Publication Date: 20260511
Application Date: 20220203
Priority Date: 20210205

Claims (20)

In a method for producing decarbonized LNG, (a) A step of at least partially liquefying a natural gas supply stream in a natural gas liquefaction system to form an LNG stream—the natural gas liquefaction system comprises at least one compressor—; (b) a step of separating the LNG stream into a flash steam stream and an LNG product stream; (c) a step of transferring at least a portion of the flash steam stream to a hydrogen production system; (d) reacting at least a portion of the flash vapor stream in a hydrogen production system to form a hydrogen-containing stream and a first CO2-rich stream; (e) generating power in a power generation system using at least a portion of the hydrogen-containing stream mixed with the first steam stream from the hydrogen production system; (f) a step of providing power to at least one compressor with at least a portion of the power generated in step (e); (g) a step of separating a second CO2-rich stream from the natural gas supply stream before performing step (a); and (h) A method for producing decarbonized LNG comprising the step of combining the first CO2-rich stream and the second CO2-rich stream to form a combined CO2 stream.
A method for producing decarbonized LNG according to claim 1, wherein the flash steam stream is at least 50 mol% methane.
A method for producing decarbonized LNG according to claim 1, wherein the hydrogen-containing stream is at least 80 mol% hydrogen.
In claim 1, (i) A method for producing decarbonized LNG, further comprising the step of liquefying at least one portion selected from the group of the first CO2-rich stream, the second CO2-rich stream, and the combined CO2 stream using a refrigeration duty from the natural gas liquefaction system.
A method for producing decarbonized LNG according to claim 1, wherein step (d) further comprises the step of reacting at least a portion of the flash steam stream with an ambient air stream in the hydrogen production system to form the hydrogen-containing stream and the first CO2-rich stream.
A method for producing decarbonized LNG according to claim 1, wherein step (d) further comprises the step of reacting at least a portion of the flash steam stream with an oxygen-containing stream in the hydrogen production system to form the hydrogen-containing stream, the first CO2-rich stream, the first steam stream, and the waste nitrogen stream.
A method for producing decarbonized LNG according to claim 6, wherein the oxygen-containing stream is ambient air.
In claim 6, (j) A method for producing decarbonized LNG, further comprising the step of passing an ambient air stream through an air separation unit to produce an oxygen-containing stream and a nitrogen-rich stream.
A method for producing decarbonized LNG according to claim 8, wherein step (e) further comprises the step of generating power in a power generation system using at least a portion of the hydrogen-containing stream and the nitrogen-rich stream.
A method for producing decarbonized LNG according to claim 1, wherein step (e) further comprises the step of driving at least one gas turbine using the hydrogen-containing stream and driving at least one steam turbine using the first steam stream to generate power in a power generation system.
A method for producing decarbonized LNG according to claim 1, wherein the power generated in step (e) includes electricity, and step (f) comprises providing at least a portion of the electricity to at least one motor attached to at least one compressor.
A method for producing decarbonized LNG according to claim 1, wherein the power generated in step (e) includes electricity, and step (f) comprises providing at least a portion of the electricity to at least one of the hydrogen production system and the natural gas liquefaction system.
In claim 1, the power generated in step (e) includes electric power, and the method (k) A method for producing decarbonized LNG, further comprising the step of sending at least a portion of the power to a process outside the natural gas liquefaction system, the hydrogen production system and the power generation system.
A method for producing decarbonized LNG according to claim 1, wherein step (e) further comprises the step of generating power in a power generation system using the hydrogen-containing stream and at least one methane-containing stream.
A method for producing decarbonized LNG according to claim 14, wherein the at least one methane-containing stream comprises at least one selected from the group of a natural gas supply stream and a flash steam stream.
In claim 1, (l) A method for producing decarbonized LNG, further comprising the step of discharging at least a portion of the hydrogen-containing stream formed in step (d) to a place of use outside the natural gas liquefaction system, the hydrogen production system and the power generation system.
A method for producing decarbonized LNG according to claim 1, wherein step (f) comprises driving the at least one compressor by mechanically coupling at least one gas turbine of the power generation system to the at least one compressor of the natural gas liquefaction system.
In claim 1, (m) A method for producing decarbonized LNG, further comprising the step of cooling the hydrogen production system using refrigeration from the natural gas liquefaction system.
In claim 1, (n) A method for producing decarbonized LNG, further comprising the step of providing a heat duty of a dryer unit using heat generated from at least one of the hydrogen production system and the power generation system, wherein the dryer unit is configured to separate moisture from a natural gas supply stream for the natural gas liquefaction system.
In claim 1, (o) A method for producing decarbonized LNG, further comprising the steps of dividing the natural gas supply stream into a first part and a second part, performing step (a) on the first part of the natural gas supply stream, and combining the second part of the natural gas supply stream with the flash steam stream before performing step (d).

Description

Method and System for Decavonized LNG Production Reducing carbon dioxide ("CO2") emissions is becoming an increasingly desirable improvement in industrial processes, including hydrocarbon treatment and power generation. Natural gas liquefaction is a process with significant power requirements, primarily for driving the compressors necessary to support the liquefaction process. Efforts are being made to reduce the carbon "footprint" of natural gas liquefaction by improving the efficiency of the liquefaction process to decrease CO2 emissions. For natural gas liquefaction plants (also referred to herein as "LNG plants") that use gas turbines to drive refrigerant compressors, further reductions in CO2 emissions through improved efficiency can be achieved by recovering heat from hot flue gas and utilizing it beneficially. This heat can be recovered by generating steam and using a combined cycle to produce additional power. Some LNG plants obtain refrigeration compression power from electricity from the power grid. Power plants supplying electricity may use gas turbines equipped with heat recovery steam generation systems for additional power and efficiency. Some power plants have reduced CO2 emissions by using hydrogen as a fuel gas or fuel gas additive. Overall CO2 emissions are reduced when this hydrogen is produced using green energy sources such as solar power or processes involving natural gas supply and CO2 capture. These processes for converting natural gas into hydrogen include steam methane reforming, where CO2 is removed from synthesis gas and/or flue gas. Optionally, this low-carbon strength hydrogen can be produced through autothermal reforming, partial oxidation, or gasification processes where CO2 is removed from effluent synthesis gas. Such improvements often result in substantially higher energy costs and require energy sources outside the natural gas liquefaction process. Therefore, more efficient and independent means are needed to reduce CO2 emissions attributed to the natural gas liquefaction process and the power required to drive the process. The present invention will be described below together with the accompanying drawings, in which similar reference numbers indicate similar elements. FIG. 1 is a block diagram illustrating a first exemplary embodiment of an interconnected natural gas liquefaction, hydrogen production, and power generation system. Figure 2 is a block diagram illustrating the natural gas liquefaction system of Figure 1 in more detail. Figure 3 is a block diagram illustrating the hydrogen production system of Figure 1 in more detail. FIG. 4 is a block diagram illustrating the power generation system of FIG. 1 in more detail. FIG. 5 is a block diagram illustrating a first alternative embodiment of the natural gas liquefaction system of FIG. 1. FIG. 6 is a block diagram illustrating a first alternative embodiment of the power generation system of FIG. 1. FIG. 7 is a table presenting fluid composition and physical parameters at multiple stream locations of exemplary embodiments illustrated in FIGS. 1 to 4. Figure 8 is a continuation of the table shown in Figure 7. The following detailed description provides merely preferred exemplary embodiments and is not intended to limit the scope, applicability, or configuration of the invention. Rather, the following detailed description of preferred exemplary embodiments will provide those skilled in the art with an explanation that enables the implementation of preferred exemplary embodiments of the invention. It should be understood that various changes may be made to the function and arrangement of elements without departing from the spirit and scope of the invention. To aid in describing the invention, directional terms may be used in the specification and claims to describe parts of the invention (e.g., top, bottom, left, right, etc.). These directional terms are intended merely to aid in describing and claiming the invention and are not intended to limit the invention in any way. Additionally, reference numbers introduced in the specification in relation to the drawings may be repeated in one or more subsequent drawings without further explanation in the specification to provide context for other features. The term “conduit” as used in the specification and claims means one or more structures through which a fluid can be transported between two or more components of a system. For example, a conduit may include pipes, ducts, passages, and combinations thereof for transporting liquids, steam, and/or gases. The term “flow connection” as used in the specification and claims is intended to mean that two or more elements are connected (directly or indirectly) in a manner that allows fluid to flow between elements, including connections that may include valves, gates, tees, or other devices capable of selectively restricting, merging, or separating fluid flow. The term "natural gas" as used in the specification and claims refers to a mix