Novel liquefied petroleum gas recovery skid-mounted device

Abstract

The utility model discloses a novel liquefied petroleum gas recovery skid-mounted device which comprises a mixed hydrocarbon buffer tank, a methane and ethane removal tower, a liquefied petroleum gas tower, a liquefied petroleum gas tower top cooler, a liquefied petroleum gas tower top separator, a liquefied petroleum gas tower reflux pump, a stable light hydrocarbon cooler, a stable light hydrocarbon buffer tank and a stable light hydrocarbon loading pump, the device is integrated into one skid-mounted device, the occupied area of the skid-mounted device is obviously reduced, equipment transportation is facilitated, and meanwhile the field installation work amount is small; the device is simple in structure and convenient to construct and install on site, realizes recovery treatment of mixed hydrocarbon in a liquefied natural gas factory, produces fuel gas, liquefied petroleum gas and stable light hydrocarbon, ensures normal production of the liquefied natural gas factory, reduces potential safety hazards of the liquefied natural gas factory, and improves economic benefits of the liquefied natural gas factory.

Description

Technical Field

[0001] The utility model belongs to the field of natural gas liquefaction, and specifically relates to a novel liquefied petroleum gas recovery skid-mounted device. Background Art

[0002] In the process of liquefied natural gas production, since natural gas contains heavy components such as propane, butane, pentane, hexane, benzene, etc., pentane, hexane, benzene and other components must be removed as harmful components in the process of liquefied natural gas production, and the removed heavy components form mixed hydrocarbons.

[0003] Natural gas liquefaction plants usually use an adsorption process to remove mixed hydrocarbons. Adsorbents are used to adsorb heavy hydrocarbon components in natural gas. The adsorbed heavy hydrocarbon components are regenerated through regeneration gas. During regeneration, the mixed hydrocarbon flow rate is uneven, with a difference of more than 10 times, making it impossible to continuously process the mixed hydrocarbons.

[0004] The natural gas components in mixed hydrocarbons include methane, ethane, propane, butane, pentane, hexane, and benzene, so the composition is complex. There is currently a lack of corresponding national standards, which makes it difficult to sell in the market and has poor economic benefits for enterprises. The saturated vapor pressure of mixed hydrocarbon products is relatively high, and safety hazards are easily formed during storage and transportation of the products. At present, due to the transportation of mixed hydrocarbons in natural gas liquefaction plants in China, many safety accidents have occurred, causing serious impacts. Therefore, the processing of mixed hydrocarbon products has seriously affected the production and operation of liquefied natural gas plants. At the same time, the overall occupied area is large, which is not convenient for construction and installation.

[0005] Usually, the liquefied petroleum gas loading system needs to be equipped with a liquefied petroleum gas buffer tank and a liquefied petroleum gas loading pump. The liquefied petroleum gas reflux pump transports the liquefied petroleum gas product to the liquefied petroleum gas buffer tank for storage. The liquefied petroleum gas buffer tank usually stores liquefied petroleum gas products. When liquefied petroleum gas is needed to be loaded, the liquefied petroleum gas in the liquefied petroleum gas buffer tank is pressurized by the liquefied petroleum gas loading pump before loading. Utility Model Content

[0006] In view of the above defects, the utility model provides a novel liquefied petroleum gas recovery skid-mounted device, including a mixed hydrocarbon buffer tank for communicating with the combined mixed hydrocarbon input from the outside, and the mixed hydrocarbon buffer tank is connected to a demethylation ethane tower through a pipeline;

[0007] A demethylethane tower top cooler for cooling is installed at the top of the demethylethane tower, and the demethylethane tower top cooler is connected to the fuel gas system through a pipeline. A demethylethane tower bottom reboiler for heating is installed at the bottom of the demethylethane tower, and the demethylethane tower bottom reboiler is connected to the liquefied petroleum gas tower through a pipeline.

[0008] A liquefied petroleum gas tower top air cooler is installed at the top of the liquefied petroleum gas tower, the liquefied petroleum gas tower top air cooler is connected with a liquefied petroleum gas tower top separator through a pipeline, the top of the liquefied petroleum gas tower top separator is connected with a fuel gas system through a pipeline, the bottom of the liquefied petroleum gas tower top separator is connected with a reflux pump through a pipeline, the reflux pump is respectively connected with the liquefied petroleum gas tower and the liquefied petroleum gas loading system through a branch pipeline, a liquefied petroleum gas tower bottom reboiler for heating is installed at the bottom of the liquefied petroleum gas tower, the liquefied petroleum gas tower bottom reboiler is connected with a stable light hydrocarbon cooler through a pipeline, the stable light hydrocarbon cooler is connected with a stable light hydrocarbon buffer tank through a pipeline, the stable light hydrocarbon buffer tank is connected with a stable light hydrocarbon loading pump for pressurization through a pipeline, and the stable light hydrocarbon loading pump is connected with the stable light hydrocarbon loading system through a pipeline;

[0009] It also includes a recovery skid. The above equipment is installed on the top of the recovery skid, and a skid frame for protection is fixed around it.

[0010] Furthermore, a liquid level control mechanism is installed inside the mixed hydrocarbon buffer tank.

[0011] Through the above technical solution, a liquid level meter, a flow control valve I and a flow meter are set in the mixed hydrocarbon buffer tank, and the liquid level meter, the flow control valve I and the flow meter are interlocked to achieve a stable mixed hydrocarbon flow to the downstream. When the upstream mixed hydrocarbon flow is large, the mixed hydrocarbon buffer tank receives excess mixed hydrocarbons; when the upstream mixed hydrocarbon flow is small, the mixed hydrocarbon buffer tank releases excess mixed hydrocarbons. The flow of mixed hydrocarbons to the downstream is controlled by the flow control valve I according to the flow meter to ensure the stability of the mixed hydrocarbon flow to the downstream.

[0012] Furthermore, a flow regulating valve II for regulating the flow is installed between the diversion pipeline and the liquefied petroleum gas loading system.

[0013] Compared with the prior art, the utility model has the following beneficial effects:

[0014] 1. Recover and process the mixed hydrocarbons in the liquefied natural gas plant to produce fuel gas, liquefied petroleum gas and stable light hydrocarbons, ensure the normal production of the liquefied natural gas plant, reduce the safety hazards of the liquefied natural gas plant, and improve the economic benefits of the liquefied natural gas plant;

[0015] 2. Integrate various equipment such as mixed hydrocarbon buffer tank, demethylation ethane tower, liquefied petroleum gas tower, liquefied petroleum gas tower top cooler, liquefied petroleum gas tower top separator, liquefied petroleum gas tower reflux pump, stable light hydrocarbon cooler, stable light hydrocarbon buffer tank, stable light hydrocarbon loading pump into a skid-mounted device. The skid-mounted device occupies a significantly smaller area, which is convenient for equipment transportation. At the same time, the on-site installation work is small, which is more convenient for on-site construction and installation;

[0016] 3. It has diverse functions and can produce fuel gas, liquefied petroleum gas and stable light hydrocarbons. It can also produce stable mixed light hydrocarbons. When the market demand for liquefied petroleum gas and stable light hydrocarbons is insufficient, it can also produce stable mixed light hydrocarbons. The stable mixed light hydrocarbons from the bottom of the demethylation ethane tower do not enter the liquefied petroleum gas tower, but directly enter the stable light hydrocarbon buffer tank through the bypass, and then the products are loaded.

[0017] 4. The liquefied petroleum gas buffer tank and liquefied petroleum gas loading pump are cancelled, and the liquefied petroleum gas tower top separator and liquefied petroleum gas reflux pump are used to realize the loading of liquefied products. When liquefied petroleum gas exists in the liquefied petroleum gas tower top separator, the liquefied petroleum gas is pressurized by the liquefied petroleum gas tower top reflux pump at the bottom of the separator. A part of the pressurized liquefied petroleum gas is directly loaded into the liquefied petroleum gas loading crane pipe; the other part of the liquefied petroleum gas returns to the liquefied petroleum gas tower as reflux. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the utility model.

[0019] In the figure: 101, mixed hydrocarbon buffer tank; 102, demethylbenzene tower; 103, demethylbenzene tower top cooler; 104, demethylbenzene tower bottom reboiler; 105, liquefied petroleum gas tower; 106, liquefied petroleum gas tower top air cooler; 107, liquefied petroleum gas tower top separator; 108, reflux pump; 109, liquefied petroleum gas tower bottom reboiler; 110, stable light hydrocarbon cooler; 111, stable light hydrocarbon buffer tank; 112, stable light hydrocarbon loading pump. DETAILED DESCRIPTION

[0020] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The drawings provide embodiments of the device. However, the device can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0021] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "set" should be understood in a broad sense, for example, they can be fixedly connected or set, or detachably connected or set, or integrally connected or set. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] Example

[0023] like Figure 1As shown, this embodiment provides a novel liquefied petroleum gas recovery skid-mounted device, including a mixed hydrocarbon buffer tank 101, a demethyl ethane tower 102, a demethyl ethane tower top cooler 103, a demethyl ethane tower bottom reboiler 104, a liquefied petroleum gas tower 105, a liquefied petroleum gas tower top air cooler 106, a liquefied petroleum gas tower top separator 107, a reflux pump 108, a liquefied petroleum gas tower bottom reboiler 109, a stable light hydrocarbon cooler 110, a stable light hydrocarbon buffer tank 111 and a stable light hydrocarbon loading pump 112, all of which are installed on the top of the recovery skid, and are integrated and arranged on the top of the recovery skid according to process requirements. A base platform is provided on the working surface of the recovery skid, and skid frames are arranged around the base platform. All equipment is located on the base platform, which is convenient for the overall movement of the liquefied petroleum gas recovery skid-mounted device;

[0024] The specific usage process is as follows:

[0025] The mixed hydrocarbons I and II from the liquefied natural gas plant merge to form mixed hydrocarbons III and enter the mixed hydrocarbon buffer tank 101. A liquid level control mechanism is installed inside the mixed hydrocarbon buffer tank 101 to ensure a stable mixed hydrocarbon flow to the downstream. The mixed hydrocarbons III in the mixed hydrocarbon buffer tank 101 are output from the bottom and are called mixed hydrocarbons IV.

[0026] Specifically, the liquid level control mechanism includes a liquid level meter, a flow control valve I and a flow meter, and the liquid level meter, the flow control valve I and the flow meter are interlocked to achieve a stable flow of mixed hydrocarbons to the downstream. When the upstream mixed hydrocarbon flow is large, the mixed hydrocarbon buffer tank receives excess mixed hydrocarbons; when the upstream mixed hydrocarbon flow is small, the mixed hydrocarbon buffer tank releases excess mixed hydrocarbons, and the flow of mixed hydrocarbons to the downstream is controlled by the flow control valve I according to the flow meter to ensure the stability of the mixed hydrocarbon flow to the downstream.

[0027] The mixed hydrocarbon buffer tank 101 is installed on a skid-mounted frame. The mixed hydrocarbon buffer tank 101 is connected to a demethylation tower 102 through a pipeline. The mixed hydrocarbon IV is transported to the demethylation tower 102 for internal treatment. A demethylation tower top cooler 103 is installed on the top of the demethylation tower 102. The top gas phase is cooled to obtain mixed hydrocarbon V. The mixed hydrocarbon V is discharged into a fuel gas system connected to the demethylation tower top cooler 103 through a pipeline. A demethylation tower bottom reboiler 104 for heating is installed at the bottom of the demethylation tower 102. After the liquid phase at the bottom of the demethylation tower 102 is heated by the demethylation tower bottom reboiler 104, a part of it circulates in the tower, and the other part of the mixed hydrocarbon VI is transported to a liquefied petroleum gas tower 105 through a pipeline as a feed.

[0028] The demethylation tower top cooler 103 is installed at the top (inner top) of the demethylation tower 102, and can directly cool the gas phase in the demethylation tower 102. The cooled gas phase goes to the fuel gas system, and the cooled liquid phase directly returns to the tower without being pressurized and then returned to the tower.

[0029] A liquefied petroleum gas tower top air cooler 106 is installed at the top of the liquefied petroleum gas tower 105. The gas phase entering the liquefied petroleum gas tower 105 and located at the top of the tower is called mixed hydrocarbon VII. The mixed hydrocarbon VII is cooled by the liquefied petroleum gas tower top air cooler 106 to form liquefied petroleum gas I. The liquefied petroleum gas tower top air cooler 106 is connected to a liquefied petroleum gas tower top separator 107 through a pipeline. The liquefied petroleum gas I is separated by the liquefied petroleum gas tower top separator 107. The gas phase at the top of the separator 107 is input into the fuel gas system through a pipeline, and the liquid phase at the bottom of the liquefied petroleum gas tower top separator 107 is pressurized by a reflux pump 108 connected by a pipeline, and after pressurization, it is divided into two paths (called liquefied petroleum gas II and liquefied petroleum gas III) through a diversion pipeline, and the liquefied petroleum gas II is measured by a flow meter installed on the pipeline and returned to the liquefied petroleum gas tower 105 as reflux, and the liquefied petroleum gas III is adjusted by a flow control valve II installed on the pipeline and then reaches the liquefied petroleum gas loading system;

[0030] A liquefied petroleum gas tower bottom reboiler 109 is installed at the bottom of the liquefied petroleum gas tower 105. After the liquid phase at the bottom of the tower is heated by the liquefied petroleum gas tower bottom reboiler 109, a part of it circulates in the tower, and the other part of the stable light hydrocarbons I is cooled by the stable light hydrocarbon cooler 110 connected through a pipeline, and then transported to the stable light hydrocarbon buffer tank 111 through a pipeline, which is called stable light hydrocarbons. The stable light hydrocarbons are pressurized by the stable light hydrocarbon loading pump 112 connected through a pipeline through the stable light hydrocarbon buffer tank 111, and the pressurized stable light hydrocarbons are transported to the stable light hydrocarbon loading system through a pipeline.

[0031] In this embodiment, the demethylation tower 102 and the demethylation tower top cooler 103, the liquefied petroleum gas tower 105 and the liquefied petroleum gas tower bottom reboiler 109 are respectively integrated and designed, which not only reduces the floor space, but also reduces the connecting pipelines, valves and automatic control systems between the equipment, thereby reducing the project investment.

[0032] It should be noted that the structure described in the utility model can be implemented in a variety of different forms and is not limited to the described embodiments. Any equivalent transformations made by ordinary technicians in this field using the contents of the utility model specification and drawings, or directly or indirectly applied to other related technical fields, such as the loading and unloading of other items, are included in the protection scope of the utility model.

Claims

1. A new type of liquefied petroleum gas recovery skid-mounted device, characterized by: It includes a mixed hydrocarbon buffer tank for communicating with the combined mixed hydrocarbons input from the outside, and the mixed hydrocarbon buffer tank is connected to the demethylation ethane tower through a pipeline; A demethylethane tower top cooler for cooling is installed at the top of the demethylethane tower, and the demethylethane tower top cooler is connected to the fuel gas system through a pipeline. A demethylethane tower bottom reboiler for heating is installed at the bottom of the demethylethane tower, and the demethylethane tower bottom reboiler is connected to the liquefied petroleum gas tower through a pipeline. A liquefied petroleum gas tower top air cooler is installed at the top of the liquefied petroleum gas tower, the liquefied petroleum gas tower top air cooler is connected with a liquefied petroleum gas tower top separator through a pipeline, the top of the liquefied petroleum gas tower top separator is connected with a fuel gas system through a pipeline, the bottom of the liquefied petroleum gas tower top separator is connected with a reflux pump through a pipeline, the reflux pump is respectively connected with the liquefied petroleum gas tower and the liquefied petroleum gas loading system through a branch pipeline, a liquefied petroleum gas tower bottom reboiler for heating is installed at the bottom of the liquefied petroleum gas tower, the liquefied petroleum gas tower bottom reboiler is connected with a stable light hydrocarbon cooler through a pipeline, the stable light hydrocarbon cooler is connected with a stable light hydrocarbon buffer tank through a pipeline, the stable light hydrocarbon buffer tank is connected with a stable light hydrocarbon loading pump for pressurization through a pipeline, and the stable light hydrocarbon loading pump is connected with the stable light hydrocarbon loading system through a pipeline; It also includes a recovery skid. The above equipment is installed on the top of the recovery skid, and a skid frame for protection is fixed around it.

2. A novel liquefied petroleum gas recovery skid-mounted device as claimed in claim 1, characterized in that: A liquid level control mechanism is installed inside the mixed hydrocarbon buffer tank.

3. A novel liquefied petroleum gas recovery skid-mounted device as claimed in claim 1, characterized in that: A flow regulating valve II for regulating flow is installed between the diversion pipeline and the liquefied petroleum gas loading system.

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