Offshore waste heat recovery type hydrogen production and methanol production platform

Abstract

According to the offshore waste heat recovery type hydrogen production and methanol production platform, a plurality of preparation devices of the offshore platform can generate waste heat in the operation process, each preparation device is provided with a heat exchanger, a plurality of heat exchangers are sequentially connected through pipelines to form a waste heat recovery pipeline, and the generated waste heat is connected into the waste heat recovery pipeline through the heat exchangers. One end of the waste heat recovery pipeline is connected with the evaporative fresh water unit, seawater circulates in the waste heat recovery pipeline, the seawater is heated by the exchanged waste heat, and the evaporative fresh water unit is sequentially connected with the hydrogen production equipment and the methanol production equipment. Seawater enters the seawater supply cabin and the reverse osmosis fresh water unit through a seawater pump and a seawater pipeline, and the reverse osmosis fresh water unit is sequentially connected with the hydrogen production equipment and the methanol production equipment. When hydrogen production and methanol synthesis are carried out, dependence on reverse osmosis fresh water preparation can be greatly reduced, waste heat resources can be fully utilized and are not wasted, and extra requirements on power load, arrangement space and cost on a platform are not generated when related functions are realized.

Description

Technical Field

[0001] The present invention belongs to the field of offshore green energy preparation, and particularly relates to an offshore waste heat recovery hydrogen and methanol production platform. Background Art

[0002] Currently, green development has become the global mainstream trend, and green technology innovation is becoming an important emerging field globally. Hydrogen energy has core advantages such as clean and efficient, storable and transportable, and rich application scenarios, and is expected to become the most competitive carbon emission reduction solution. At the same time, in the energy and chemical industry, preparing methanol based on green hydrogen reaction is one of the important ways to efficiently convert and utilize carbon dioxide and "fix carbon with hydrogen".

[0003] The initial raw material for the above-mentioned green hydrogen or methanol preparation process is fresh water. In offshore hydrogen and methanol production platforms, since there is no direct supply of fresh water, seawater is usually desalinated to obtain raw material fresh water. This desalination process is achieved through large-flow watermakers (mainly reverse osmosis watermakers). However, due to the large desalination volume, the reverse osmosis membranes of such watermakers need to be frequently replaced, resulting in high costs. One method of making fresh water is to heat seawater and reduce the air pressure (vacuum pumping) to make it evaporate quickly, and fresh water is produced by distillation. In engineering, vacuum evaporation watermakers are usually used to achieve this. Heating seawater requires a corresponding heat source. There are often a large number of heat exchanges in various functions and process flows of offshore production facilities, but the heat energy in these processes has not been effectively utilized, resulting in a large waste of energy. If the waste heat can be recovered and reused and fresh water can be produced through an evaporation watermaker, the overall economy of the offshore hydrogen and methanol production process can be greatly improved.

[0004] For the waste heat that can be recovered and reused on the offshore hydrogen and methanol production platform, there is waste heat generated by the exhaust of generator sets, waste heat generated by the central fresh water cooling system for cooling various equipment on the ship (air compressors, HPUs, air-cooled equipment, etc.), waste heat generated during the hydrogen production process, waste heat generated during the methanol production process, etc. In view of the above situation, an offshore production platform can be designed to recover and utilize the above waste heat to produce fresh water and further produce hydrogen and methanol, so as to further improve the green degree and economy of the hydrogen and methanol production processes. Summary of the Invention

[0005] To solve the above problems, the present invention provides an offshore waste heat recovery hydrogen and methanol production platform, aiming to reuse the waste heat generated by various devices on the offshore platform and improve the green degree of hydrogen and methanol production. The technical solution adopted is as follows:

[0006] An offshore waste heat recovery hydrogen and methanol production platform. The offshore platform is equipped with multiple preparation devices. During the operation of these multiple preparation devices, waste heat is generated. Each preparation device is equipped with a heat exchanger, and multiple heat exchangers are sequentially connected through pipelines to form a waste heat recovery pipeline. The generated waste heat is introduced into the waste heat recovery pipeline through the heat exchanger; the preparation device includes a hydrogen production device and a methanol production device.

[0007] One end of the waste heat recovery pipeline is connected to the seawater supply tank, and the other end is connected to the evaporative water maker unit. Seawater flows through the waste heat recovery pipeline, and the exchanged waste heat heats the seawater. The evaporative water maker is sequentially connected to the hydrogen production device and the methanol production device.

[0008] Seawater enters the seawater supply tank and the reverse osmosis water maker unit through a seawater pump and a seawater pipeline. The reverse osmosis water maker unit is sequentially connected to the hydrogen production device and the methanol production device.

[0009] For the above-mentioned offshore waste heat recovery hydrogen and methanol production platform, further, a low-temperature seawater branch extends from the passage where the waste heat recovery pipeline is connected to the evaporative water maker unit, and the low-temperature seawater branch is connected to the seawater supply tank.

[0010] For the above-mentioned offshore waste heat recovery hydrogen and methanol production platform, further, a seawater circulation pump is provided on the passage where the waste heat recovery pipeline is connected to the evaporative water maker unit.

[0011] For the above-mentioned offshore waste heat recovery hydrogen and methanol production platform, further, the methanol production device is connected to a methanol external transportation device.

[0012] For the above-mentioned offshore waste heat recovery hydrogen and methanol production platform, further, the preparation device also includes other waste heat sources such as a generator exhaust pipe and a central fresh water cooling system.

[0013] For the above-mentioned offshore waste heat recovery hydrogen and methanol production platform, further, there are two seawater circulation pumps.

[0014] The beneficial effects of the present invention are as follows:

[0015] 1. When the present invention is used for hydrogen production and methanol synthesis, it can greatly reduce the dependence on reverse osmosis fresh water production.

[0016] 2. The waste heat resources of the present invention can be fully utilized without waste.

[0017] 3. When the present invention realizes related functions, it does not impose excessive additional requirements on the power load, layout space and cost on the platform. Brief Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the system of the present invention;

[0019] Among them, 1 - seawater supply pump, 2 - reverse osmosis water production unit, 3 - hydrogen production equipment, 4 - methanol production equipment, 5 - evaporative water production unit, 6 - seawater supply tank, 7 - low-temperature seawater branch, 8 - high-temperature seawater branch, 9 - heat exchanger, 10 - preparation device, 11 - seawater circulation pump, 12 - waste heat recovery pipeline. Detailed implementation manner

[0020] The present invention will be further described in conjunction with the accompanying drawings.

[0021] An offshore waste heat recovery type hydrogen and methanol production platform, as Figure 1 shown. First, the seawater supply pump 1 provides seawater for the production of raw fresh water. The seawater first enters the seawater supply tank 6 and, driven by the seawater circulation pump 11 (configured as 2x100% to ensure the functionality of the system), flows through each heat exchanger 9 via the waste heat recovery pipeline 12. Each heat exchanger 9 exchanges waste heat with each preparation device (mainly waste heat from hydrogen production equipment, waste heat from methanol production equipment, waste heat from the exhaust pipe of the generator set, waste heat from the central fresh water cooling system, waste heat from other equipment, etc.). The waste heat exchanged heats the seawater flowing in the waste heat recovery pipeline 12. When the seawater temperature reaches the standard (40 - 50 °C), it enters the evaporative water production unit 5 through the high-temperature seawater branch 8. The produced raw fresh water enters the hydrogen production equipment 3 for hydrogen production. The produced hydrogen can be exported or used as fuel to supply back to the offshore production platform (determined according to the actual application scenario of the platform); the produced hydrogen is mainly supplied to the methanol production equipment 4 for manufacturing methanol. The produced methanol can be exported or used as fuel to supply back to the offshore production platform (determined according to the actual application scenario of the platform).

[0022] When the seawater temperature in the waste heat recovery pipeline 12 does not reach the standard (less than 40 °C), the seawater is controlled by the valve group in the system to flow through the low-temperature seawater branch 7 and return to the seawater supply tank 6 without entering the high-temperature seawater branch 8, and then flows through each heat exchanger 9 again until the seawater temperature is heated to the standard by the waste heat and then enters the evaporative water production unit 5 through the high-temperature seawater branch 8 to produce fresh water. The produced fresh water enters the hydrogen production equipment 3 to ensure the smooth progress of the hydrogen and methanol production process.

[0023] Temperature sensors and control valves are equipped in the system to control the flow direction of seawater in the system. When the seawater temperature reaches the standard, it enters the evaporative water production unit 5 through the high-temperature seawater branch 8 to produce fresh water. When the seawater temperature does not reach the standard, it is ensured that it circulates and is heated in the waste heat recovery pipeline 12 through the low-temperature seawater branch 7 until the temperature reaches the standard and then enters the evaporative water production unit 5 through the high-temperature seawater branch 8 to produce fresh water to ensure the realization of the above process.

[0024] When there is insufficient waste heat on the offshore platform or other special circumstances prevent the production of raw fresh water using waste heat, the seawater pumped by the platform can directly enter the reverse osmosis water maker 2 through the control of the valve group in the system to produce raw fresh water to meet the temporary production needs of the platform. During normal production with sufficient waste heat, all fresh water is prepared by the evaporative water maker 5, and the reverse osmosis water maker 2 serves as a backup.

Claims

1. An offshore waste heat recovery hydrogen and methanol production platform, characterized in that: The offshore platform is equipped with multiple preparation devices, which generate waste heat during operation. Each preparation device is equipped with a heat exchanger, and multiple heat exchangers are connected in sequence through pipelines to form a waste heat recovery pipeline. The generated waste heat is connected to the waste heat recovery pipeline through the heat exchanger; the preparation device includes hydrogen production equipment and methanol production equipment; One end of the waste heat recovery pipeline is connected to the seawater supply tank, and the other end is connected to the evaporative fresh water generator. Seawater flows in the waste heat recovery pipeline, and the exchanged waste heat heats the seawater. The evaporative fresh water generator is connected to the hydrogen production equipment and the methanol production equipment in turn. Seawater enters the seawater supply tank and the reverse osmosis fresh water making unit through the seawater pump and the seawater pipeline. The reverse osmosis fresh water making unit is connected to the hydrogen production equipment and the methanol production equipment in turn.

2. The offshore waste heat recovery hydrogen and methanol production platform according to claim 1, characterized in that: A low-temperature seawater branch extends from the passage connecting the waste heat recovery pipeline and the evaporative fresh water generator unit, and the low-temperature seawater branch is connected to the seawater supply tank.

3. The offshore waste heat recovery hydrogen and methanol production platform according to claim 1, characterized in that: A seawater circulation pump is provided on the passage connecting the waste heat recovery pipeline and the evaporative fresh water generator unit.

4. The offshore waste heat recovery hydrogen and methanol production platform according to claim 1, characterized in that: The methanol production equipment is connected to the methanol export equipment.

5. The offshore waste heat recovery hydrogen and methanol production platform according to claim 1, characterized in that: The preparation unit also includes a generator exhaust duct and a central fresh water cooling system.

6. The offshore waste heat recovery hydrogen and methanol production platform according to claim 3, characterized in that: There are two seawater circulation pumps.

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