CN212269471U

CN212269471U - Synthetic ammonia separation tower unit for liquefied natural gas production system

Info

Publication number: CN212269471U
Application number: CN202020882453.2U
Authority: CN
Inventors: 贺泯乾; 刘生全; 王涛; 焦建军
Original assignee: Inner Mongolia Sanjujiajing New Energy Co ltd
Current assignee: Inner Mongolia Sanjujiajing New Energy Co ltd
Priority date: 2020-05-22
Filing date: 2020-05-22
Publication date: 2021-01-01
Anticipated expiration: 2030-05-22

Abstract

The utility model discloses a synthetic ammonia knockout tower unit for liquefied natural gas production system, it includes filling tube, one-level water-cooling tower, one-level ammonia knockout tower, cold ware of second grade ammonia and second grade ammonia knockout tower, and it still includes buffer water tank and heat exchanger. The advantages are that: BOG discharged by the LNG storage tank and circulating water of the water cooling tower exchange heat by using the heat exchanger, and the circulating water of the primary water cooling tower is precooled by using the BOG, so that the gas temperature of the primary water cooling tower is reduced, the cooling capacity of the primary water cooling tower is improved, the requirement of a secondary ammonia cooler on the cooling capacity of the cooler is further reduced, the energy consumption of the cooler is reduced, and the cost is reduced; the cold energy of the BOG before entering the BOG compressor is fully utilized, the low temperature resistance requirement of the BOG compressor is reduced, independent BOG temperature rising equipment is not required to be arranged, the energy consumption is reduced, the service life of the compressor is prolonged, and the production cost is reduced; the application effectively utilizes the cooling capacity of the BOG, improves the energy utilization rate and achieves the purposes of energy conservation and consumption reduction.

Description

Synthetic ammonia separation tower unit for liquefied natural gas production system

The technical field is as follows:

the utility model relates to the technical field of liquefied natural gas production, in particular to a synthetic ammonia separation tower unit for a liquefied natural gas production system.

Background art:

the natural gas is synthesized by the coke oven gas through methanation reaction, LNG is obtained by liquefaction, the effective components of the coke oven gas can be fully utilized, the economic value is high, and the wide attention is paid; the main process flow comprises several units of compression, pretreatment, desulfurization, methanation, raw and cold separation tower, drying, liquefaction, synthetic ammonia and the like, and the produced liquefied natural gas is stored by an LNG storage tank. After the storage tank stores the Liquid Natural Gas (LNG), the temperature in the tank body is generally about-111 ℃ to-111 ℃, the higher the temperature is, the larger the amount of the Liquid Natural Gas (LNG) gasified into the gaseous natural gas (BOG) is, the larger the amount of the BOG stored in the storage tank is, the higher the pressure in the storage tank is, and when the set pressure of the storage tank is reached, the air must be discharged. In order to recover the BOG and improve the liquefaction efficiency, the BOG gas needs to be pressurized and cooled by a BOG compressor to be reliquefied, but since the temperature of the BOG is low (about 120 ℃), in order to reduce the low temperature resistance requirement of the compressor, a temperature raising device needs to be arranged in front of the compressor to raise the temperature of the BOG, so that the cost of recovering the BOG is high. In addition, nitrogen-rich and hydrogen-rich tail gas produced in the production process can be sent to a synthetic ammonia system to synthesize liquid ammonia, mixed gas produced by the synthetic ammonia system contains ammonia gas, hydrogen gas, nitrogen gas and methane, liquid ammonia needs to be discharged by a separation tower unit through a separation tower, the separation tower unit comprises a primary water cooling tower, a primary ammonia separation tower, a secondary ammonia cooler and a secondary ammonia separation tower which are sequentially connected, wherein the primary water cooling tower is influenced by the environmental temperature to cause the temperature of the primary ammonia separation tower to be high, and the cold quantity provided by the secondary ammonia cooler is increased to cause the energy consumption of the ammonia cooler to be increased.

The utility model has the following contents:

the utility model aims to provide a synthetic ammonia knockout tower unit for liquefied natural gas production system has reduced manufacturing cost.

The utility model discloses by following technical scheme implement: a synthetic ammonia separation tower unit for a liquefied natural gas production system comprises a feed pipe, a primary water cooling tower, a primary ammonia separation tower, a secondary ammonia cooler, a secondary ammonia separation tower, a cache water tank and a heat exchanger, wherein a water outlet of the primary water cooling tower is communicated with an inlet pipeline of the cache water tank, an outlet of the cache water tank is respectively communicated with an inlet of a circulating pump and an inlet pipeline of a cooling pump, an outlet of the circulating pump is communicated with a water inlet pipeline of the primary water cooling tower, an outlet of the cooling pump is communicated with a heat medium inlet pipeline of the heat exchanger, and a heat medium outlet of the heat exchanger is communicated with the inlet pipeline of the cache water tank; and a refrigerant inlet of the heat exchanger is communicated with an outlet of the BOG pipe network, and a refrigerant outlet of the heat exchanger is communicated with an inlet pipeline of the BOG compressor.

Furthermore, the inlet of the buffer water tank is communicated with a water supplementing pipe, and a water supplementing control valve is arranged on the water supplementing pipe.

Further, a jacket is sleeved outside a pipeline between the heat exchanger and the BOG compressor, an inlet of the jacket is communicated with the feeding pipe through a feeding branch pipe, and a branch pipe control valve is arranged on the feeding branch pipe; and the outlet of the jacket is communicated with a feed inlet pipeline of the primary water-cooling tower.

The utility model has the advantages that: BOG discharged by the LNG storage tank and circulating water of the water cooling tower exchange heat by using the heat exchanger, and the circulating water of the primary water cooling tower is precooled by using the BOG, so that the gas temperature of the primary water cooling tower is reduced, the cooling capacity of the primary water cooling tower is improved, the requirement of a secondary ammonia cooler on the cooling capacity of the cooler is further reduced, the energy consumption of the cooler is reduced, and the cost is reduced; the cold energy of the BOG before entering the BOG compressor is fully utilized, the low temperature resistance requirement of the BOG compressor is reduced, independent BOG temperature rising equipment is not required to be arranged, the energy consumption is reduced, the service life of the compressor is prolonged, and the production cost is reduced; the application effectively utilizes the cooling capacity of the BOG, improves the energy utilization rate and achieves the purposes of energy conservation and consumption reduction.

Description of the drawings:

fig. 1 is a schematic view of the entire structure of embodiment 1.

Fig. 2 is a schematic view of the entire structure of embodiment 2.

The system comprises a feed pipe 1, a primary water cooling tower 2, a primary ammonia separation tower 1, a secondary ammonia cooler 4, a secondary ammonia separation tower 1, a buffer water tank 6, a heat exchanger 7, a circulating pump 8, a cooling pump 9, a BOG pipe network 10, a BOG compressor 11, a water replenishing pipe 12, a water replenishing control valve 13, a jacket 14, a feed branch pipe 15 and a branch pipe control valve 16.

The specific implementation mode is as follows:

in the description of the present invention, it should be noted that, as the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, but does not indicate or imply that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" as appearing herein are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Example 1: as shown in fig. 1, a synthetic ammonia separation tower unit for an lng production system, which comprises a feed pipe 1, a first-stage water cooling tower 2, a first-stage ammonia separation tower 1, a second-stage ammonia cooler 4, a second-stage ammonia separation tower 1, a buffer water tank 6 and a heat exchanger 7, wherein a water outlet of the first-stage water cooling tower 2 is communicated with an inlet pipeline of the buffer water tank 6, an outlet of the buffer water tank 6 is respectively communicated with an inlet of a circulating pump 8 and an inlet pipeline of a cooling pump 9, an outlet of the circulating pump 8 is communicated with a water inlet pipeline of the first-stage water cooling tower 2, an outlet of the cooling pump 9 is communicated with a heat medium inlet pipeline of the heat exchanger 7, and a heat medium outlet of the heat exchanger 7 is communicated with an inlet; and a refrigerant inlet of the heat exchanger 7 is communicated with an outlet of the BOG pipe network 10, and a refrigerant outlet of the heat exchanger 7 is communicated with an inlet pipeline of the BOG compressor 11.

The inlet of the buffer water tank 6 is communicated with a water supplementing pipe 12, and the water supplementing pipe 12 is provided with a water supplementing control valve 13.

The working principle is as follows: water at the bottom of the first-stage water-cooling tower 2 enters a buffer water tank 1 below through a pipeline to be collected, and then is sent to a heat exchanger 7 through a cooling pump 1 to exchange heat with BOG gas sent by a BOG pipe network 10, the BOG gas subjected to heat exchange and temperature rise enters a BOG compressor 11 to be compressed and recovered, circulating water subjected to heat exchange and temperature reduction enters a buffer water tank 6 to be mixed with circulating water inside the buffer water tank, and the overall temperature of the circulating water is reduced; then the circulating water is sent to a primary water cooling tower 2 by a circulating pump 8, the nitrogen-rich and hydrogen-rich tail gas sent by a feed pipe 1 is cooled, and then the tail gas sequentially enters a primary ammonia separation tower 1, a secondary ammonia cooler 4 and a secondary ammonia separation tower 1 to be respectively subjected to primary separation, secondary cooling and secondary separation; when the circulating water volume of the first-level water cooling tower 2 is insufficient, a water supplementing control valve 11 is opened, and water is supplemented into the cache water tank 1 through a water supplementing pipe 12.

Example 2: as shown in fig. 2, the whole structure is the same as that of example 1, except that a jacket 14 is sleeved outside the pipeline between the heat exchanger 7 and the BOG compressor 11, the inlet of the jacket 14 is communicated with the feed pipe 1 through a feed branch pipe 15, and a branch pipe control valve 16 is arranged on the feed branch pipe 15; the outlet of the jacket 14 is communicated with the feed inlet pipeline of the primary water cooling tower 2. In the winter in the north, the outdoor temperature is low, and particularly, the temperature of circulating water in the cache water tank 6 is low due to the influence of the environmental temperature, so that the temperature rising effect of BOG in the heat exchanger 7 is reduced; at this time, the branch pipe control valve 16 is opened, so that part of the tail gas sent from the charging pipe 1 enters the jacket 14, and the BOG discharged from the heat exchanger 7 is subjected to secondary heat exchange and temperature rise, thereby reducing the damage to the BOG compressor 11.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

Claims

1. A synthetic ammonia separation tower unit for a liquefied natural gas production system comprises a feed pipe, a primary water cooling tower, a primary ammonia separation tower, a secondary ammonia cooler and a secondary ammonia separation tower, and is characterized by further comprising a buffer water tank and a heat exchanger, wherein a water outlet of the primary water cooling tower is communicated with an inlet pipeline of the buffer water tank, an outlet of the buffer water tank is respectively communicated with an inlet of a circulating pump and an inlet pipeline of a cooling pump, an outlet of the circulating pump is communicated with a water inlet pipeline of the primary water cooling tower, an outlet of the cooling pump is communicated with a heat medium inlet pipeline of the heat exchanger, and a heat medium outlet of the heat exchanger is communicated with an inlet pipeline of the buffer water tank; and a refrigerant inlet of the heat exchanger is communicated with an outlet of the BOG pipe network, and a refrigerant outlet of the heat exchanger is communicated with an inlet pipeline of the BOG compressor.

2. The synthetic ammonia separation tower unit for the liquefied natural gas production system according to claim 1, wherein a water replenishing pipe is connected to an inlet of the buffer water tank, and a water replenishing control valve is installed on the water replenishing pipe.

3. The synthetic ammonia separation tower unit for the liquefied natural gas production system according to claim 1 or 2, wherein a jacket is sleeved outside a pipeline between the heat exchanger and the BOG compressor, an inlet of the jacket is communicated with the feed pipe through a feed branch pipe, and a branch pipe control valve is provided on the feed branch pipe; and the outlet of the jacket is communicated with a feed inlet pipeline of the primary water-cooling tower.