Protective flushing device for mechanical sealing system of sulfuric acid method alkylation reactor

Abstract

The utility model relates to a protection flushing device for a mechanical sealing system of a sulfuric acid method alkylation reactor, and belongs to the field of chemical anti-corrosion equipment. Comprising a filter, a coalescence dehydrator, a circulating isobutane flushing line and a cold isobutane flushing line, the circulating iso-butane flushing line is connected to an inlet of the filter from a circulating iso-butane feeding line, the cold iso-butane flushing line is connected to the inlet of the filter from a tube pass outlet of the feeding cooler, an outlet of the filter is connected with an inlet of the coalescence dehydrator, and an outlet of the coalescence dehydrator is connected with a flushing fluid pipeline in the mechanical sealing system. According to the utility model, the service life of the mechanical seal of the alkylation reactor is greatly prolonged, temporary shutdown caused by corrosion failure of the mechanical seal does not occur any more in actual use, the operation safety of the device is greatly improved, the yield is improved, the maintenance frequency and cost are reduced, and the profitability of the device is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of sulfuric acid method alkylating reactor mechanical sealing system protection flushing device, belong to chemical anticorrosion equipment field. BACKGROUND

[0002] Alkylation reaction refers to the chemical reaction of isobutane and carbon four monoolefin under the action of acidic catalyst, mainly addition reaction, to generate 2,2,4-trimethylpentane-based alkylated oil, which is used in industry to produce high-quality gasoline blending components. With the continuous improvement of environmental standards, alkylated oil production devices are increasingly valued. The acidic catalyst used in large-scale devices is sulfuric acid, hydrofluoric acid or solid acid, and in practical applications, sulfuric acid is mainly used because of its low price and safer operation compared to hydrofluoric acid and the like.

[0003] The alkylating reactor is filled with sulfuric acid. Due to the corrosive effect of sulfuric acid, the service life of the mechanical seal device is relatively short, typically only about 3-6 months, significantly increasing the operation risk and maintenance cost of the device and reducing its production capacity. The current solution is to use reaction effluent or high-purity n-butane, product alkylated oil, etc. as flushing fluid to dilute sulfuric acid and protect the reactor mechanical seal. However, the reaction effluent still contains sulfuric acid, high-purity n-butane affects product quality, and product alkylated oil causes material circulation waste. Moreover, the material temperature is relatively high, which cannot effectively protect the reactor mechanical seal device and causes product quality to decline and production costs to increase. Therefore, how to optimize the composition and properties of the mechanical seal system flushing fluid at low cost, improve the use environment of the mechanical seal, and extend the service life of the mechanical seal system is a technical problem that needs to be solved. SUMMARY

[0004] According to the problem described in the background, the utility model solves the problem of:

[0005] The service life of the sulfuric acid method alkylating reactor mechanical seal device is relatively short, typically only about 3-6 months, significantly increasing the operation risk and maintenance cost of the device and reducing its production capacity.

[0006] To achieve the above-mentioned purpose, the utility model provides the following technical solutions:

[0007] The application discloses a sulfuric acid method alkylating reactor mechanical seal system protection flushing device, which comprises a filter, a coalescence dehydrator, a circulating isobutane flushing line and a cold isobutane flushing line; the circulating isobutane flushing line is connected to the filter inlet from a circulating isobutane feed line, the cold isobutane flushing line is connected to the filter inlet from a feed cooler pipe passage outlet, the filter outlet is connected to the coalescence dehydrator inlet, and the coalescence dehydrator outlet is connected to a flushing liquid pipeline in the mechanical seal system; valves are arranged on the circulating isobutane flushing line and the cold isobutane flushing line, and a valve is arranged on the coalescence dehydrator outlet.

[0008] Preferably, a circulating isobutane feed adjusting valve is arranged on the circulating isobutane feed line, and the circulating isobutane flushing line is connected to the filter inlet before the circulating isobutane feed adjusting valve.

[0009] Preferably, a flushing liquid pipeline control valve is arranged on the flushing liquid pipeline, and the coalescence dehydrator outlet is connected to the rear of the flushing liquid pipeline control valve.

[0010] The introduction part of the patent introduces a low-temperature cooled feed flushing liquid through the cold isobutane flushing line, so that the temperature of the mechanical seal device is reduced, the corrosion is slowed down, and the long-period operation of the seal is facilitated. Meanwhile, the cooled feed material is all the material of the original alkylating reaction feed system itself, does not need to be introduced by additional special equipment, does not increase additional flow, does not circulate additional material, does not consume additional energy, and the system is simple, easy to realize and low in cost.

[0011] The introduction part of the patent introduces a low-temperature cooled feed flushing liquid through the cold isobutane flushing line, so that the temperature of the mechanical seal device is reduced, the corrosion is slowed down, and the long-period operation of the seal is facilitated. Meanwhile, the cooled feed material is all the material of the original alkylating reaction feed system itself, does not need to be introduced by additional special equipment, does not increase additional flow, does not circulate additional material, does not consume additional energy, and the system is simple, easy to realize and low in cost.

[0012] The patent introduces a precise filter and a coalescence dehydrator into the flushing system, filters and removes impurities and dehydrates the material entering the alkylating reactor mechanical seal flushing system, further optimizes the material composition, slows down the flushing of mechanical impurities on the seal, reduces the water content, increases the acid concentration, makes the seal only contact high-concentration sulfuric acid and does not reflect the corrosiveness of sulfuric acid, and greatly increases the service life of the mechanical seal. Since the flushing system flow is low, the fixed investment cost and the maintenance cost of the added precise filter and coalescence dehydrator are low, and the cost advantage is obvious compared with the prolonged service life of the mechanical seal.

[0013] The patent can reasonably select low-temperature cooling feed or refined isobutane as the protective flushing liquid of the mechanical seal device of the reactor, especially can meet the requirement of stable pressure of the flushing system during start-up and shutdown of the alkylation reactor, has very high flexibility, and the stable pressure also guarantees long-period operation of the mechanical seal.

[0014] The patent has the following beneficial effects:

[0015] After the patent is put into use, the service life of the mechanical seal of the alkylation reactor is greatly increased to more than one year from the original 3-6 months, and the temporary shutdown caused by corrosion failure of the mechanical seal does not occur in actual use, the device operation safety is greatly improved, the yield is improved, the maintenance frequency and cost are reduced, and the device profitability is improved. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A schematic view of a protective flushing device

[0017] In the figure: 1 is a circulating isobutane flushing line; 2 is a cold isobutane flushing line; 3 is a filter; 4 is a coalescing dehydrator; 5 is a circulating isobutane feed line; 6 is a raw material isobutane feed line; 7 is a feed cooler; 8 is a flushing liquid pipeline; 9 is a circulating isobutane feed regulating valve; and 10 is a flushing liquid pipeline control valve. DETAILED DESCRIPTION

[0018] EMBODIMENT

[0019] A mechanical seal system protective flushing device for a sulfuric acid alkylation reactor comprises a filter 3, a coalescing dehydrator 4, a circulating isobutane flushing line 1 and a cold isobutane flushing line 2; the circulating isobutane flushing line 1 is connected to the inlet of the filter 3 from the circulating isobutane feed line 5, the cold isobutane flushing line 2 is connected to the inlet of the filter 3 from the outlet of the tube side of the feed cooler 7, the outlet of the filter 3 is connected to the inlet of the coalescing dehydrator 4, and the outlet of the coalescing dehydrator 4 is connected to the flushing liquid pipeline 8 in the mechanical seal system; valves are arranged on the circulating isobutane flushing line 1 and the cold isobutane flushing line 2, and a valve is arranged at the outlet of the coalescing dehydrator 4.

[0020] A circulating isobutane feed regulating valve 9 is arranged on the circulating isobutane feed line 5, and the circulating isobutane flushing line 1 is connected to the inlet of the filter from before the valve of the circulating isobutane feed regulating valve 9.

[0021] A flushing liquid pipeline control valve 10 is arranged on the flushing liquid pipeline 8, and the outlet of the coalescing dehydrator 4 is connected to the rear of the valve of the flushing liquid pipeline control valve 10.

[0022] When the alkylate reactor is starting up and preparing to feed, due to the unstable pressure at the valve on the cold isobutane flushing line 2, the mechanical seal system protection flushing fluid is provided by the stable refined isobutane from the circulating isobutane flushing line 1, and the whole process is to open the valve on the circulating isobutane flushing line 1, close the valve on the cold isobutane flushing line 2, pass through the filter 3 and the coalescence dewatering device 4, open the valve on the outlet of the coalescence dewatering device 4, close the flushing fluid pipeline control valve 10, and the flushing fluid enters the end face of the mechanical seal device, and the mechanical seal flushing protection process is completed.

[0023] When the alkylate reactor is running stably, the mechanical seal system protection flushing fluid can be changed from the stable refined isobutane from the circulating isobutane flushing line 1 to the low-temperature and less water-containing feed from the cold isobutane flushing line 2, and the specific operation process is to slowly open the valve on the cold isobutane flushing line 2, and simultaneously according to the remote and on-site pressure after the flushing fluid pipeline control valve 10, the opening degree of the valve on the circulating isobutane flushing line 1 and the valve on the cold isobutane flushing line 2 is adjusted, until the valve on the circulating isobutane flushing line 1 is fully closed, the valve on the cold isobutane flushing line 2 is opened, and the pressure after the flushing fluid pipeline control valve 10 is stable and higher than the reactor pressure by 0.1 MPa, at this time, the flushing fluid supply process is to open the valve on the cold isobutane flushing line 2, pass through the filter 3 and the coalescence dewatering device 4, open the valve on the outlet of the coalescence dewatering device 4, close the flushing fluid pipeline control valve 10, and the flushing fluid enters the end face of the mechanical seal device, and the mechanical seal flushing protection process is completed.

[0024] As can be seen from the description, the flushing fluid pipeline control valve 10 does not need to be opened at any time, because the material properties have been completely replaced by the material from the circulating isobutane flushing line 1 or the cold isobutane flushing line 2, which is much lower.

Claims

1. A protective flushing device for the mechanical seal system of a sulfuric acid alkylation reactor, characterized in that: The invention comprises a filter (3), a coalescing dehydrator (4), a circulating isobutane flushing line (1) and a cold isobutane flushing line (2); the circulating isobutane flushing line (1) is connected from a circulating isobutane feed line (5) to the inlet of the filter (3); the cold isobutane flushing line (2) is connected from the outlet of the feed cooler (7) pipe to the inlet of the filter (3); the outlet of the filter (3) is connected to the inlet of the coalescing dehydrator (4); the outlet of the coalescing dehydrator (4) is connected to the flushing liquid pipeline (8) in the mechanical seal system; valves are provided on the circulating isobutane flushing line (1) and the cold isobutane flushing line (2); and a valve is provided at the outlet of the coalescing dehydrator (4).

2. The protective flushing device for the mechanical seal system of a sulfuric acid alkylation reactor according to claim 1, characterized in that: A circulating isobutane feed regulating valve (9) is provided on the circulating isobutane feed line (5), and the circulating isobutane flushing line (1) is connected to the filter inlet from the valve front of the circulating isobutane feed regulating valve (9).

3. The protective flushing device for the mechanical seal system of a sulfuric acid alkylation reactor according to claim 1, characterized in that: The flushing liquid pipeline (8) is provided with a flushing liquid pipeline control valve (10), and the outlet of the coalescing dehydrator (4) is connected to the rear end of the flushing liquid pipeline control valve (10).

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