Gas supply system for the feed heater and thermal oil heater of naphtha hydrotreating unit

Abstract

A gas supply device for the feed heater and thermal oil furnace of a naphtha hydrogenation unit is characterized by: a valve assembly installed on the inlet pipeline of the fuel gas separator; the inlet pipeline of the valve assembly is divided into two lines, one for natural gas and the other for the main fuel gas pipeline; the outlet pipeline of the fuel gas separator is also divided into two lines, one connected to the feed heater and the other connected to the thermal oil furnace. This invention, by adding a natural gas pipeline, switches the gas supply to the feed heater and thermal oil furnace to natural gas when flue gas indicators are abnormal, avoiding abnormal flue gas from the heater due to changes in fuel gas composition. This ensures stable operation of the unit and compliant flue gas emissions, meeting environmental protection requirements and reducing environmental risks for enterprises. It largely maintains the original structure of existing equipment, requiring no major modifications, and features low modification costs and high economic benefits.

Description

Technical Field

[0001] This utility model belongs to the field of naphtha processing technology, specifically relating to the gas supply device for the feed heating furnace and heat transfer oil furnace of a naphtha hydrogenation unit. Background Technology

[0002] With increasingly stringent environmental protection requirements, the control of waste gas emissions in industrial production processes has become a crucial issue that enterprises must address. In the 500,000-ton / year coal tar full-fraction hydrogenation to naphthenic oil project of Shenmu Fuyou Energy Technology Co., Ltd., the fuel gas supply for the feed heater of the naphtha hydrogenation unit and the heat transfer oil furnace of the naphthenic oil separation unit poses a challenge to the stable operation of the unit and the compliance of flue gas emissions with standards.

[0003] The fuel gas sampled from the naphtha hydrotreating unit's feed heater and the naphthenic oil separator's thermal oil furnace is sourced from the company's fuel gas. This fuel gas exhibits some instability during actual operation, containing a portion of recovered gaseous media. Changes in the composition of the recovered gaseous media can lead to higher pollutant emission levels in the heater flue gas, even exceeding the prescribed limits. This not only affects the normal operation of the unit but may also have adverse environmental impacts, increasing the company's environmental risks and operating costs.

[0004] Therefore, in response to the shortcomings of existing naphtha hydrogenation units, an economical and effective technical solution is needed that can solve the problem of excessive emissions from the heating furnace caused by changes in fuel gas composition without significantly increasing costs, while ensuring stable operation of the unit and compliance with emission standards. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the defects of the prior art and provide a gas supply device for the feed heating furnace and heat transfer oil furnace of a naphtha hydrogenation unit with simple structure, low cost and stable operation.

[0006] The technical solution adopted to solve the above technical problems is: a gas supply device for the feed heating furnace and thermal oil furnace of a naphtha hydrogenation unit, wherein a valve assembly is installed on the gas inlet pipeline of the fuel gas separator, the gas inlet pipeline of the valve assembly is divided into two paths, one is a natural gas pipeline and the other is a fuel gas main pipeline, and the gas outlet pipeline of the fuel gas separator is divided into two paths, one is connected to the feed heating furnace and the other is connected to the thermal oil furnace.

[0007] As a preferred technical solution, the valve assembly includes: a first gate valve, a pneumatic regulating valve, a second gate valve, a third gate valve, and a shut-off valve; the first gate valve, the pneumatic regulating valve, and the second gate valve are connected in series along the gas path direction on the inlet pipeline of the fuel gas separator; a branch pipe is provided between the first gate valve and the pneumatic regulating valve; the third gate valve is connected to the branch pipe; one end of the shut-off valve is connected in parallel to the inlet of the first gate valve, and the other end is connected in parallel to the outlet of the second gate valve.

[0008] As a preferred technical solution, a fourth gate valve and a fifth gate valve are connected in series on the natural gas pipeline, a branch pipe is provided between the fourth gate valve and the fifth gate valve, and a sixth gate valve is connected to the branch pipe.

[0009] As a preferred technical solution, the fuel gas main pipeline is connected to a flare recovery gas pipe and a natural gas branch pipe on the gas inlet side.

[0010] As a preferred technical solution, a seventh gate valve and an eighth gate valve are connected in series on the fuel gas main pipeline, a branch pipe is provided between the seventh gate valve and the eighth gate valve, and a ninth gate valve is connected to the branch pipe.

[0011] The beneficial effects of this utility model are as follows:

[0012] This invention, by adding a natural gas pipeline, switches the gas supply to the feed heating furnace and thermal oil furnace to natural gas when flue gas indicators are abnormal. This avoids abnormal flue gas from the heating furnace caused by changes in fuel gas composition, ensuring stable operation of the equipment and compliant flue gas emissions, meeting environmental protection requirements and reducing the environmental risks for enterprises.

[0013] This utility model largely maintains the original structure of existing equipment, without requiring significant modifications to the existing equipment, and features low modification costs and high economic benefits. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model.

[0015] Among them: fourth gate valve 1, fifth gate valve 2, natural gas pipeline 3, first gate valve 4, pneumatic regulating valve 5, second gate valve 6, fuel gas separator 7, shut-off valve 8, ninth gate valve 9, seventh gate valve 10, eighth gate valve 11, fuel gas main pipeline 12, sixth gate valve 13, and third gate valve 14. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the present invention is not limited to the following embodiments.

[0017] exist Figure 1In this embodiment, a fuel gas supply device for the feed heater and thermal oil furnace of a naphtha hydrogenation unit includes a fuel gas separator 7. A valve assembly is installed on the inlet pipeline of the fuel gas separator 7. The inlet pipeline of the valve assembly is divided into two lines: one is a natural gas pipeline 3, and the other is a fuel gas main pipeline 12. The inlet side of the fuel gas main pipeline 12 is connected to a flare recovery gas pipe and a natural gas branch pipe. The outlet pipeline of the fuel gas separator 7 is also divided into two lines: one is connected to the feed heater, and the other is connected to the thermal oil furnace. The fuel gas separator 7 effectively separates liquid impurities from the fuel gas, preventing liquid from entering the furnace combustion system and avoiding problems such as incomplete combustion and flameout caused by liquid accumulation, thereby improving the safety and stability of combustion.

[0018] The valve assembly in this embodiment includes: a first gate valve 4, a pneumatic regulating valve 5, a second gate valve 6, a third gate valve 14, and a shut-off valve 8. The first gate valve 4, pneumatic regulating valve 5, and second gate valve 6 are connected in series along the gas path to the inlet pipeline of the fuel gas separator 7. The pneumatic regulating valve 5 is used to finely regulate the flow rate of the fuel gas. A branch pipe is provided between the first gate valve 4 and the pneumatic regulating valve 5, and the third gate valve 14 is connected to the branch pipe. One end of the shut-off valve 8 is connected in parallel to the inlet of the first gate valve 4, and the other end is connected in parallel to the outlet of the second gate valve 6. When the pneumatic regulating valve 5 is being inspected, the shut-off valve 8 is opened, and gas passes through the shut-off valve 8. The valve assembly is used to regulate the pressure of the inlet pipeline of the fuel gas separator 7 to ensure pressure stability.

[0019] In this embodiment, a fourth gate valve 1 and a fifth gate valve 2 are connected in series on the natural gas pipeline 3. A branch pipe is provided between the fourth gate valve 1 and the fifth gate valve 2, and a sixth gate valve 13 is connected to the branch pipe. The fourth gate valve 1 and the fifth gate valve 2 are used to control the on / off of the natural gas pipeline 3. By adjusting the opening of these two gate valves, the flow rate of natural gas can be assisted in regulating.

[0020] In this embodiment, a seventh gate valve 10 and an eighth gate valve 11 are connected in series on the fuel gas main pipeline 12. A branch pipe is provided between the seventh gate valve 10 and the eighth gate valve 11, and a ninth gate valve 9 is connected to the branch pipe. The seventh gate valve 10 and the eighth gate valve 11 are used to control the gas flow rate in the fuel gas main pipeline 12. By adjusting the opening of these two gate valves, the amount of gas entering the fuel gas separator 7 can be precisely controlled, thereby meeting the gas demand of the feed heating furnace and the thermal oil furnace under different operating conditions. At the same time, when maintenance, repair or replacement of the fuel gas main pipeline 12 or related equipment is required, the seventh gate valve 10 and the eighth gate valve 11 can cut off the gas supply, isolate the fuel gas main pipeline 12 from the subsequent system, and ensure the safe conduct of maintenance work.

[0021] In this embodiment, the third gate valve 14, the sixth gate valve 13, and the ninth gate valve 9 installed on the pipeline are all drain valves, which are used to connect to the nitrogen pipeline during maintenance to replace the gas in the pipeline.

[0022] Under normal operating conditions, the seventh gate valve 10 and the eighth gate valve 11 are opened, and fuel gas is supplied by the fuel gas main pipeline 12. When the flue gas indicators are abnormal, the seventh gate valve 10 and the eighth gate valve 11 are closed, and the fourth gate valve 1 and the fifth gate valve 2 are opened. The gas used by the feed heating furnace and the thermal oil furnace is changed to natural gas to achieve stable operation of the equipment.

Claims

1. A fuel gas supply device for a feed heating furnace and a heat transfer oil furnace of a naphtha hydrogenation plant, characterized by: The fuel gas separator is equipped with a valve assembly on its inlet pipeline. The inlet pipeline of the valve assembly is divided into two lines: one is a natural gas pipeline and the other is a fuel gas main pipeline. The fuel gas separator is also divided into two lines: one is connected to the feed heating furnace and the other is connected to the thermal oil furnace.

2. The gas supply device for the feed heating furnace and thermal oil furnace of the naphtha hydrotreating unit according to claim 1, characterized in that, The valve assembly includes: a first gate valve, a pneumatic regulating valve, a second gate valve, a third gate valve, and a shut-off valve; the first gate valve, the pneumatic regulating valve, and the second gate valve are connected in series along the gas path direction on the inlet pipeline of the fuel gas separator; a branch pipe is provided between the first gate valve and the pneumatic regulating valve; the third gate valve is connected to the branch pipe; one end of the shut-off valve is connected in parallel to the inlet of the first gate valve, and the other end is connected in parallel to the outlet of the second gate valve.

3. The gas supply device for the feed heating furnace and thermal oil furnace of the naphtha hydrotreating unit according to claim 1, characterized in that, The natural gas pipeline is connected in series with a fourth gate valve and a fifth gate valve. A branch pipe is provided between the fourth gate valve and the fifth gate valve, and a sixth gate valve is connected to the branch pipe.

4. The gas supply device for the feed heating furnace and thermal oil furnace of the naphtha hydrotreating unit according to claim 1, characterized in that, The fuel gas main pipeline is connected to a flare recovery gas pipe and a natural gas branch pipe on the inlet side.

5. The gas supply device for the feed heating furnace and thermal oil furnace of the naphtha hydrotreating unit according to claim 1 or 4, characterized in that, The fuel gas main pipeline is connected in series with a seventh gate valve and an eighth gate valve. A branch pipe is provided between the seventh gate valve and the eighth gate valve, and a ninth gate valve is connected to the branch pipe.

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