Propylene separating and refining system

Abstract

The utility model relates to a propylene separating and refining system which comprises a light component removal tower, a crude propylene cooler and a refining unit, a first port of the crude propylene cooler is connected with a propylene recovery tank, a second port of the crude propylene cooler is connected with the top of the light component removal tower, a third port of the crude propylene cooler is connected with the bottom of the light component removal tower, a fourth port of the crude propylene cooler is connected with the refining unit, and a fifth port of the crude propylene cooler is connected with the propylene recovery tank. A first port and a second port of the crude propylene cooler are communicated, a third port and a fourth port of the crude propylene cooler are connected, and the refining unit comprises one or more of a COS hydrolyzer device, a zinc oxide desulfurization device, an arsenic removal device and a molecular sieve dehydration device which are connected in series. After light components in the propylene are removed and recovered, the propylene is refined and dried and then is recycled with fresh feed, and the propylene is continuously purified by the separation tower in the system, so that the yield of the propylene is increased.

Description

TECHNICAL FIELD

[0001] The utility model relates to polypropylene production in the propylene recycling technical field, especially a propylene separation and refining system. BACKGROUND

[0002] Polypropylene (PP) belongs to thermoplastic resin, is one of five general resins, has chemical resistance, heat resistance, electrical insulation, high strength mechanical properties and good high wear resistance processing performance etc., is widely developed and applied in many fields such as machinery, automobile, electronic equipment, building, textile, packaging, forestry, fishery and food industry.

[0003] Polypropylene production system needs to balance the excess propylene of the system and discharge when starting and stopping and when system fluctuation, in the normal production process of polypropylene, the amount of reducing the system liquid phase propane accumulation and reducing the system gas phase inert component concentration continuous discharge is high, according to the crude propylene amount of about 2 tons / hour when sending out during starting balance, about 0.5 tons / hour during normal production, causing the large loss of enterprise benefit. UTILITY MODEL CONTENT

[0004] In view of the deficiencies of the prior art existing at present, the utility model provides a propylene separation and refining system for improving propylene recovery rate.

[0005] In order to achieve the above-mentioned purpose, the utility model provides a propylene separation and refining system, has the following technical scheme: the system includes light removal tower, crude propylene cooler, refining unit;The first port of crude propylene cooler is connected with propylene recovery tank, the second port of crude propylene cooler is connected with the top of light removal tower, the third port of crude propylene cooler is connected with the bottom of light removal tower, the fourth port of crude propylene cooler is connected with the refining unit, the first port and the second port of crude propylene cooler are connected, the third port and the fourth port of crude propylene cooler are connected, the refining unit includes one or multiple in series of COS hydrolyzer device, zinc oxide desulfurization device, arsenic removal device, molecular sieve dehydration device.

[0006] Preferably, the system includes high-pressure washing tower and crude propylene pump, the top and bottom of high-pressure washing tower are connected with reaction system, the inlet and discharge end of crude propylene pump are connected with high-pressure washing tower.

[0007] Preferably, the system includes propylene buffer tank with cooling function, the propylene buffer tank is connected with the first port of crude propylene cooler and the discharge end of crude propylene pump respectively.

[0008] Preferably, a condenser is arranged at the top of the light component removal tower, a reboiler is arranged at the bottom of the light component removal tower, and a flare header is connected to the gas outlet of the light component removal tower to discharge non-condensable gas.

[0009] Preferably, the COS hydrolysis device, the ZnO desulfurization device, the arsenic removal device and the molecular sieve dehydration device each have a main body and an inner cavity in the main body, the inner cavity is sequentially provided with a first screen, a functional agent layer and a second screen from bottom to top, the main body has a feed inlet at the lower side and a discharge outlet at the upper side, the outlet end of the feed inlet is arranged in the first screen, the inlet end of the discharge outlet is arranged at the upper side of the second screen, the first screen and the second screen are each filled with inert porcelain balls for adsorbing moisture, the functional agent layer of the COS hydrolysis device is a COS hydrolysis agent layer, the functional agent layer of the ZnO desulfurization device is a ZnO desulfurization agent layer, the functional agent layer of the arsenic removal device is an arsenic removal agent layer, and the functional agent layer of the molecular sieve dehydration device is a 3A molecular sieve layer.

[0010] The propylene separation and refining system of the utility model, after removing light components in the recycled propylene, carries out refining and drying and then is reused with fresh feed, is continuously refined through the separation tower in the system, thereby only producing crude propylene with higher propane content, greatly reduces the purity of propylene in the crude propylene and improves the yield of propylene. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical scheme in the embodiments of the utility model, the following briefly introduces the drawings needed to be used in the embodiments.

[0012] Figure 1 It is a structure diagram of the propylene separation and refining system of the utility model.

[0013] REFERENCE NUMERALS

[0014] 1 light component removal tower; 2 refining unit; 3 crude propylene cooler; 4 high-pressure washing tower; 5 crude propylene pump; A reaction system; B propylene buffer tank. DETAILED DESCRIPTION

[0015] In order to more clearly illustrate the technical content of the utility model, the following further describes in combination with specific embodiments.

[0016] As Figure 1The utility model discloses a propylene separation and refining system, which has the advantages of improving the yield of crude propylene, not increasing the tower, reducing the water content and recycling, solves the problem of crude propylene delivery and improves the yield of crude propylene.

[0017] The first port of the crude propylene cooler 3 is connected to a propylene recovery tank (not shown) to transport liquid-phase crude propylene, the second port of the crude propylene cooler 3 is connected to the top of the light-removing tower 1, the third port of the crude propylene cooler 3 is connected to the bottom of the light-removing tower 1, that is, the liquid outlet at the bottom of the light-removing tower is connected to the third port of the crude propylene cooler 3, the fourth port of the crude propylene cooler 3 is connected to the refining unit 2, the first port and the second port of the crude propylene cooler 3 are connected in communication, and the third port and the fourth port of the crude propylene cooler 3 are connected. In this way, after the crude propylene enters the system, it is first heated to about 40 DEG C through heat exchange with the propylene discharged from the bottom of the light-removing tower, and then enters the propylene light-removing tower. Light impurities such as CO, O2, CO2, a small amount of other light component impurities and a small amount of propylene are distilled from the top of the light-removing tower and enter the intermediate gas tank of the device, the liquid in the kettle of the light-removing tower is refined propylene, which is heated through the crude propylene cooler and the feed propylene, and then goes to the refining unit to obtain refined propylene and enters the reaction system.

[0018] The refining unit 2 includes one or multiple COS hydrolysis device, zinc oxide desulfurization device, arsenic removal device and molecular sieve dehydration device connected in series. The refining unit 2 is used for drying and refining the crude propylene to remove impurities.

[0019] The COS hydrolysis device, zinc oxide desulfurization device, arsenic removal device and molecular sieve dehydration device all have a main body and an inner cavity in the main body. The inner cavity is sequentially provided with a first mesh screen, a functional agent layer and a second mesh screen from bottom to top. The main body has a feed inlet at the lower side and a discharge outlet at the upper side. The outlet end of the feed inlet is arranged in the first mesh screen, and the inlet end of the discharge outlet is arranged at the upper side of the second mesh screen. Inert porcelain balls for adsorbing moisture are filled in the first mesh screen and the second mesh screen. The functional agent layer of the COS hydrolysis device is a COS hydrolysis agent layer, the functional agent layer of the zinc oxide desulfurization device is a ZnO desulfurizer layer, the functional agent layer of the arsenic removal device is an arsenic removal agent layer, and the functional agent layer of the molecular sieve dehydration device is a 3A molecular sieve layer.

[0020] COS hydrolysis device, zinc oxide desulfurization device, arsenic removal device, molecular sieve dehydration device can be used in series, two molecular sieve dehydration devices can be used in parallel.

[0021] As shown in the figure, the system comprises a high-pressure washing tower 4 and a crude propylene pump 5, the top and bottom of the high-pressure washing tower 4 are connected with a reaction system A, and the entering end and discharging end of the crude propylene pump 5 are connected with the high-pressure washing tower 4. Figure 1 The propylene refined by the refining unit 2 is mixed with raw materials to participate in the reaction, the high-pressure washing tower 4 is used for separating propylene and propane, high-purity propane is taken out from the bottom of the tower for external delivery, and the propylene at the top of the tower reenters the reaction unit for polymerization reaction, so that the effective recycling of propylene is achieved, the loss of propylene is reduced, and the purpose of improving the propylene yield is achieved.

[0022] The system comprises a propylene buffer tank B with a cooling function, and the propylene buffer tank B is connected with the first port of the crude propylene cooler 3 and the discharging end of the crude propylene pump 5 respectively.

[0023] Based on the system of the utility model, the recycling purification is used, the technical requirements of the equipment are reduced, the investment of the new equipment is greatly reduced, the realization difficulty is reduced, the implementation cost is reduced, the frequency of crude propylene delivery is reduced under the condition that the production capacity is unchanged, the loss of low-price sales is reduced, and the decline of the delivery amount also reduces the safety risk of loading and unloading.

[0024] The propylene separation and refining system of the utility model, after removing the light components in the recycled propylene, carries out refining and drying, and then is reused with fresh feed, is continuously purified through the separation tower in the system, so that only the crude propylene with high propane content is produced, the purity of propylene in the crude propylene is greatly reduced, and the yield of propylene is improved.

[0025] In this specification, the utility model has been described with reference to its specific embodiments. However, it is obvious that various modifications and changes can be made without departing from the spirit and scope of the utility model. Therefore, the specification and drawings should be considered as illustrative rather than restrictive.

Claims

1. A propylene separation purification system characterized by, The system comprises a light-removing tower, a crude propylene cooler, a refining unit; the first port of the crude propylene cooler is connected with a propylene recovery tank, the second port of the crude propylene cooler is connected with the top of the light-removing tower, the third port of the crude propylene cooler is connected with the bottom of the light-removing tower, the fourth port of the crude propylene cooler is connected with the refining unit, the first port and the second port of the crude propylene cooler are connected in communication, the third port and the fourth port of the crude propylene cooler are connected, and the refining unit comprises one or multiple devices in series, such as a COS hydrolysis device, a zinc oxide desulfurization device, an arsenic removal device, and a molecular sieve dehydration device.

2. The propylene separation purification system according to claim 1, characterized by, The system comprises a high-pressure washing tower and a crude propylene pump, the top and the bottom of the high-pressure washing tower are connected with a reaction system, and the inlet end and the discharge end of the crude propylene pump are connected with the high-pressure washing tower.

3. The propylene separation purification system according to claim 2, characterized by, The system comprises a propylene buffer tank with a cooling function, the propylene buffer tank is connected with the first port of the crude propylene cooler and the discharge end of the crude propylene pump, respectively.

4. The propylene separation purification system according to claim 1, characterized by, The top of the light-removing tower is provided with a condenser, the bottom of the light-removing tower is provided with a reboiler, and the top gas outlet of the light-removing tower is connected with a flare header to discharge non-condensable gas.

5. The propylene separation purification system according to claim 1, characterized by, The COS hydrolysis device, the zinc oxide desulfurization device, the arsenic removal device, and the molecular sieve dehydration device each have a main body and an inner cavity in the main body, the inner cavity is sequentially provided with a first mesh screen, a functional agent layer, and a second mesh screen from bottom to top, the main body has a feed inlet at the lower side and a discharge outlet at the upper side, the outlet end of the feed inlet is arranged in the first mesh screen, the inlet end of the discharge outlet is arranged at the upper side of the second mesh screen, the first mesh screen and the second mesh screen are each filled with inert porcelain balls for adsorbing moisture, the functional agent layer of the COS hydrolysis device is a COS hydrolysis agent layer, the functional agent layer of the zinc oxide desulfurization device is a ZnO desulfurizer layer, the functional agent layer of the arsenic removal device is an arsenic removal agent layer, and the functional agent layer of the molecular sieve dehydration device is a 3A molecular sieve layer.

Images