EP3206970A1

EP3206970A1 - Storage facility for the storage of highly volatile hydrocarbons

Info

Publication number: EP3206970A1
Application number: EP14799100.4A
Authority: EP
Inventors: Heinrich Imhof
Original assignee: Imhof Heinrich
Current assignee: IMHOF, HEINRICH
Priority date: 2014-10-16
Filing date: 2014-10-16
Publication date: 2017-08-23
Anticipated expiration: 2034-10-16
Also published as: US20170305657A1; EP3206970B1; WO2016058622A1

Abstract

The invention relates to a storage facility for the storage of highly volatile hydrocarbons, comprising at least one vertical round tank (1) which is equipped with a floating cover (5), covering the liquid surface, in the form of a floating roof or a floating ceiling, wherein an annular space (8) formed between the cover (5) and tank wall (3) is sealed by means of flexible sealing elements (9) and wherein fittings (12, 13) for automatic control of overpressures and underpressures in the space (4) under the cover (5) are integrated into the cover (5). The fittings (12, 13) of the at least one round tank (1) are connected to a vapour line (14), the upper end of which is led out of the tank (1) and is in turn connected to a separate vapour expansion tank (15), wherein the round tank (1) and the vapour compensation tank (15) form a closed system.

Description

"Storage facility for volatile hydrocarbons"

description

The present invention relates to a storage facility for storage of volatile hydrocarbons with at least one vertical round container according to the preamble of claim 1.

The storage of volatile hydrocarbons in non-pressurized and above-ground storage tanks is usually carried out in vertical, round-bottomed tanks fitted with floating covers to avoid emissions and fire risks. Large containers of this type are usually equipped as floating tanks without a fixed roof. Smaller storage containers and containers for finished products often have a fixed roof and are equipped with a Innenschwimmdecke.

Even after 100 years of developing the storage concepts, the operation of these storage containers is still subject to temporarily increased emissions and associated fire risks.

The also used storage of volatile hydrocarbons in closed containers, without floating cover and instead with vapor deposition and damper recovery, leads to a high cost in the treatment of large amounts of steam by the daily "breathing" the container and is unattractive for large container volumes or not Therefore, especially in storage facilities with large individual containers, the application of the floating cover means that no further measures are needed to remove the vapors produced in the tanks.

When storing volatile hydrocarbons, various problems can be identified that arise in the existing deposits.

A first problem area are steam leaks in special operating situations, the extreme heating of the contents of the storage tanks on summer days, the Inadvertent discharge of air or vapors with tank filling (eg during ship unloading or from the pipeline), the introduction of warmed storage products and the release of stored products. The resulting excess vapors escaping from overpressure fittings and the edges of the floating covers and can in extreme cases lead to the lifting of the cover of the storage liquid with the risk that serious damage to the storage container to fire hazards.

A second problem area is that the container volume can not be fully utilized because the floating cover loses its emission-limiting effect as soon as the liquid level in the container drops below the support height of the floating cover supporting the floating cover at the bottom of the container. In this fluid level, a safety valve opens to protect against vacuum and to prevent possible destruction of the floating cover. In this case, air from the atmosphere replaces the removed storage liquid and, in the event of subsequent filling of the container, forcibly leads to vapor emissions which amount to up to one kilogram of stored product per cubic meter of air. Therefore, the loss of storage volume is about 10% to 15%.

The third problem to be noted is that in order to minimize the emissions mentioned above in the context of the second problem area, in particular floating roof tanks (which do not have a fixed tank roof) are height-adjustable

Floating roof supports are provided, with which the floating roof is supported at low liquid level at the tank bottom. For normal operation of the container, the roof supports are moved to a higher position so that they protrude only about 1 m from the bottom of the floating cover; The distance between tank bottom and deepest floating roof position is only about 1 m and the tank volume is better usable. Before planned repairs to the container, the roof supports are displaced so that they fill the container

Keep the floating roof in a high position about 2 m above the bottom of the tank. Adjusting the floating roof supports involves risks for the installation personnel and fire hazards. Frequently, concentric, mutually displaceable tubes (leg and supporting sheath) are used for the floating roof supports. det, which can corrode and then be difficult to move. However, if the container additionally has a fixed roof and an inner floating cover, it often dispenses with the adjustability of the supports, since the necessary work in the event of a full tank and closed space is anyway too high a risk. This means that the respective floating ceilings are usually equipped only with fixed supports (2 m support height).

A further, fourth problem area is to be seen in that after a full emptying of the container for a designated repair, the gas space must be degassed under the floating cover. For this purpose, external companies are needed, which suck and burn the vapors from the dead space of the container. This work can take several weeks for larger containers and leads to enormous cost and security risks. In addition, during the last combustion phase of this work, as the concentration of vapors decreases, a foreign gas must be mixed prior to incineration, a measure required for environmental reasons.

Another fifth problem area is the fact that the enormous expense of emptying the container not only leads to enormous costs and risks, but also represents a major impediment to a flexible re-allocation of the tank space for a possible product change. This is in contrast to today's demand that tank farms must be very flexible to changing storage needs designed to rent the existing storage volumes well.

The present invention is based on a storage for storage of volatile hydrocarbons with at least one vertical round container, wherein the round container is provided with a liquid surface covering, floating cover in the form of a floating roof or a floating cover; the annular space formed between the cover and the container wall is sealed by means of flexible sealing elements. In the floating cover fittings are integrated for the automatic control of the pressure and the negative pressure in the space below the cover.

Based on this prior art, the present invention is based on the object, the above-mentioned emissions and fire risks drastically to reduce. Furthermore, the storage space is to be made almost 100% usable and the flexibility of the storage space for product re-allocations can be increased. It should also be possible to make emissions usable for energy purposes.

This object is achieved by the features of claim 1. Preferred embodiments of the invention will become apparent from the dependent claims.

The invention is characterized in that the fittings of the at least one round container are connected to a Dämperneitung, which is guided at the upper edge of the container (preferably over the upper edge of the container) and in turn connected to a separate vaporizer reservoir, the Buffers of vapors which under certain operating conditions must be supplied or removed from the space under the cover. The round tank and the vapor expansion tank form a closed system, whereby a complete separation between atmosphere and storage product takes place. The fittings are designed to protect the space below the floating cover against overpressure as well as against a potential vacuum.

As a result of the measures according to the invention, the problems listed above do not occur or are largely avoided.

In a preferred embodiment, it is provided that the Dämperneitung within the round container has a vertically extending portion which is formed as a bellows and which expands or contracts depending on the floating height of the floating cover. Because of this bellows, the ducting is extended or shortened according to the position of the floating cover as a result of container filling.

It is also contemplated that the bellows of the ducting surround a fixed support and that the bellows be secured to the upper end of the support. The attachment point of the bellows to the carrier forms a fixed reference point for the bellows. The lower end of the bellows is preferably attached to a structural part of the floating roof and changes with the floating position of the floating roof. Another advantage is achieved when the support, which surrounds the bellows, is simultaneously formed as sampling, Peil-, measuring and / or guide tube or as a roof support, whereby at the same time the vertical passage of the carrier is sealed by the floating cover. The bellows is already present on some containers today, since the vertical ducts through the floating cover today represents the largest emission source on the container. In an alternative embodiment, the Dämimineitung can be performed within a round container along a roll ladder. Such a roller ladder is pivotally connected to the region of the upper edge of the round container while the lower end is provided with rollers and rolls along a runway resting on the floating cover. With changing floating height of the floating roof, the roller ladder changes its inclination, the rollers are always guided along the runway. Thus, the Rolleiter represents a stable support for the dairy line.

The vaporizer reservoir is preferably one having a flexible diaphragm on which a ballast weight acts. About the size of the ballast weight used, the necessary pressure in the space of the expansion tank can be adjusted.

In a further embodiment, the annular space between the floating cover, the container wall and an edge seal above the liquid surface should be connected to the space below the floating cover to dissipate also from this annulus accumulating there vapors.

In particular, in order to utilize the proportion of vapors from the round container, which can not be taken up by the vaporizer reservoir or, if appropriate, other collecting devices, it is provided to connect a steam utilization and / or steam combustion device to the vapors expansion tank.

The invention is preferably to be used when the deposit comprises several storage containers. In such a case, these storage containers are connected to a common vaporizer reservoir. The vaporizer surge tank with its ballast weight, taking into account the flow resistances of the ducting, should be designed to avoid negative pressure in the space below the cover by supplying vapors into this space, and should also be designed to have a given gauge pressure in this space below the cover by absorbing vapors from the room.

In order to support a discharge of the vapors to the vaporizer reservoir, a fan can be arranged in the dimming line, which is controlled by pressure sensors in the tank container below the floating cover.

The invention also relates to a storage facility with a plurality of storage containers, wherein these storage containers are subdivided into at least two groups, wherein the assignment to the at least two groups takes place after their pressure exerted on the liquid via the floating cover. Each storage container in a group is associated with a vaporizer reservoir adapted to this pressure. The different vaporizer reservoirs are connected via a vapor equalization line into which a booster blower for delivering vapors from the low pressure vaporizer reservoir to the higher pressure vaporizer reservoir is inserted. This results in a flexible and automatically effective system for receiving vapors to be discharged from the respective containers, to buffer them and to feed them back to the container interiors, if necessary. The system operates on the one hand by the weight of the floating cover and on the other hand by the ballast weight in the vapor expansion tank independently.

It is further provided that the remaining in the lowest position of the floating cover of the round container between the floating cover and the container bottom space is connected to a Spülflüssigkeitsvorrat and existing in the remaining space after emptying of the container hydrocarbon vapors by introducing the rinsing liquid into the round container to Support height of the floating cover to the vaporizer reservoir to be dissipated. In such a case, water or storage can be used as low vapor pressure fluids can be used from other storage tanks in the reservoir.

The deposit according to the invention thus has the following advantages in the various embodiments:

- Increase of the usable storage volume by about 10%

- Avoiding emissions at overpressure under the floating cover

- Avoid emissions when the containers are emptied below the support height of the floating cover

- elimination of the costly and time-consuming degassing of the rooms under the

floating cover before inspecting and repairing the storage container

Further details and features of the invention will become apparent from the following description of exemplary embodiments with reference to the drawing. In the drawing shows

1 shows a cross section of a vertical round container in the form of an open floating tank with a floating cover and a guided on a Peilrohr duct in the form of a bellows, which is connected to a vapor expansion tank,

Figure 2 shows a cross section of another vertical round container also in the form of an open floating tank with a floating

Cover and a guided along a roller ladder duct in the form of a hose,

3 shows a cross section of a vertical round container according to the

1 with an additional fixed roof, and an indoor floating ceiling in steel pan construction,

Figure 4 shows a cross section of a vertical round container according to the

3, wherein the floating cover is designed as a lightweight construction with a vapor space between the liquid surface and covering sheet metal skin, Figure 5 is a schematic representation of a deposit with three storage containers, a storage tanks associated with these vapors and a gas utilization / gas combustion device, and

Figure 6 is a schematic representation of a deposit with grouped into two groups storage containers, each associated with a vaporizer reservoir, which are connected to each other via a vapor equalization line and a booster blower.

The round container, which is shown in cross-section in Figure 1 and designated by the reference numeral 1, represents an open floating roof tank and comprises a container bottom 2 and a vertical container wall 3. The located in the container space 4 liquid (volatile hydrocarbons) is of a floating cover 5 covered.

The floating cover 5 is supported by a ring pontoon 6 above the liquid distributed around the peripheral portion of the floating cover 5. The remaining between the outer wall 7 of the floating cover 5 and the inside of the container wall 3 annular space 8 is closed by flexible sealing elements 9, so that on the one hand no rainwater can penetrate into the space below the floating cover 5 and on the other no vapors from the room below can escape the floating cover 5, wherein, as indicated in the figure, such vapors also accumulate in the annular space 8 above the liquid surface 10.

On the underside of the floating cover 5 is distributed over the surface of a plurality of supports 11, with which the floating cover 5 rests on the container bottom 2, when the storage liquid is emptied to a residual volume from the container 1. After the then remaining liquid is completely emptied from the container 1 and the space 4 between the container bottom 2 and floating cover 5 is degassed, the floating cover can also be inspected and maintained from the bottom.

In the floating cover 5 is on the one hand a valve in the form of a pressure relief valve 12 for automatically controlling an overpressure in the Be container space 4 and on the other hand, a valve in the form of a vacuum check valve 13 for automatic control of a negative pressure in the container space 4. Both valves 12, 13 are connected via a Dämbsteitung 14 with a vapor compensating tank 15 outside of the round container 1.

The Dämperneitung 14 includes within the container space a vertically extending portion which is formed as a bellows 16. This bellows 16 extends or shortens depending on the floating height of the floating cover 5, as indicated in the lower part of the bellows 16. In the embodiment shown in Figure 1, the bellows 16 surrounds a fixed support 17, which is connected by means of brackets 18 at its lower and at its upper end to the container wall 3. This carrier 7 is additionally designed as a sampling, direction finding and measuring tube, to which it is provided in the longitudinal direction with a series of evenly spaced holes 19, which guarantee that the level division in the sounding tube gives the correct values. The lower end of the bellows 16 is attached to an enlarged housing part 20a of the jacket tube 20 for Peilrohrdurchführung.

The vaporizer surge tank 15 includes a flexible membrane 21 with a ballast weight 22 acting thereon, which establishes the pressure in the equalization space 23.

The vapors expansion tank 15 is designed with the ballast weight 22, taking into account the flow resistance of the Dämperneitung 14 so that it avoids a negative pressure in the space 4 below the cover 5 by supplying vapors in the required amount and time in this space 4, and is on the other hand also designed so that it avoids a predetermined overpressure in this space 4 below the cover 5 by absorbing vapors in the required amount and time from the room 4. The necessary pressure equalization is ensured by the pressure relief valve 12 and the vacuum valve 13.

In Figure 1 it can be seen that the vacuum valve 13 has an actuating rod 24 which is made longer than the length of the supports 11, so that the end of this operating rod 24 with the container bottom 2 of the round container 1 comes into contact before the floating cover. 5 with the supports 11 on the floor gets up. Thereby, the negative pressure valve 13 is actuated by the operating rod 24 before the floating cover 5 rests on the container bottom 2 with the supports 1 1, whereby the steam supply is ensured from the vapors expansion tank.

In order to vent the annular space 8 between the outer wall 7 of the floating cover 5 and the container wall 3, which is sealed to the atmosphere by the flexible sealing elements 9, to vent at excess steam, or to avoid a vacuum situation when emptying the container, this annular space 8 is over at least one further insulation line 25 connected to the container space 4.

It should be noted that in the following description of various embodiments as illustrated in the figures, not all components will be described again for an embodiment when described or explained with reference to another embodiment. Accordingly, the description of the various components for one embodiment may be applied to the respective components of another embodiment without explicitly mentioning it. Also, individual components of an embodiment can be transferred to another embodiment or used there.

In contrast to Figure 1, a further cross section of a vertical round container 1 is shown in Figure 2, which corresponds to the round container 1 of Figure 1 in its essential structure. In Figure 2, however, the Dämperneitung 14 is guided along a roller ladder 27. The roller ladder 27 is pivotally mounted on a bracket, which is designated 18 'and rolls with its free lower end by means of rollers 27' on a guide track 26 which rests on the floating cover 5, so that the roller ladder 27 when the floating height of the floating cover 5 changes along the guide track 26 can move. The Dämperneitung 14, which is designed in this embodiment as a flexible hose is thereby guided on the roller ladder 27. Usually, such a roller ladder 27 is usually present on containers without a fixed roof, so that this roller ladder 27 is used as a guide element for the dairy line 14.

In the figure 3 an embodiment is shown, which is comparable to that of Figure 1; However, the round container 1 with an additional fixed roof. 8 fitted. Through this fixed roof 8, the interior of the round container 1 and thus the floating cover 5 is protected against rainfall, so that the floating cover 5 must carry no precipitation and no ring pontoon needed. The construction of the insulating line 14 with the vertical section designed as a bellows 16, which surrounds the stationary carrier 17 serving as a sighting tube 17, is identical to the arrangement of FIG. 1.

The illustrated in cross-section vertical round container 1 of Figure 4 corresponds to that of Figure 3, although the floating cover 5 is designed as a lightweight link construction. This embodiment is used when a Innenschwimmdecke is subsequently introduce into a closed container through the Mantelmannloch.

Typically, deposits comprise a plurality of round containers 1, as shown in Figures 1 to 4. In Figure 5, a deposit in a schematic representation with three storage containers is shown as an example, the upper storage container is one with a fixed roof and with lightweight floating cover 5b .entsprechend Figure 4, the middle storage container such a fixed roof and paving ceiling, according to FIG 3, while the lower storage container is an open storage container with floating cover, a so-called floating roof tank, as shown in FIG. The respective Dämpfeleitungen 14, which are associated with the individual storage containers are connected to the compensation chamber 23 of a common vaporizer reservoir 15. In one of the Dämperneitungen 14, which is associated with the uppermost storage container with lightweight floating cover 5 b, a booster fan 29 is inserted. This is required because the lightweight floating ceiling 5 b can not exert the necessary gas pressure to automatically press vapors from the room 4 in the gas space 23 of the vaporizer tank 15. In the event of a negative pressure in grassy space 4 when the storage container is emptied, vapors from the vapors expansion tank 15 automatically flow back into the gas space 4 when the valves 30 are closed and the valve 32 is open in the bypass line 31.

The shut-off valves 33 are always open during normal operation of the deposit and are only required if one of the storage containers is operationally separate from the rest of the storage facility. The volume of the equalization space 23 of the vaporizer Equalization tank 15 can be increased or decreased by the flexible membrane 21 in a suitable manner, wherein the pressure in the dummy line 14 corresponds to the set via the ballast weight 22 pressure in the expansion chamber 23.

If the volume of the equalizing space 23 of the vaporizing surge tank 15 is insufficient to receive the vapors discharged from the storage tanks, a gas recovery / gas burning device 34 connected to the vaporizing surge tank 15 may be provided for further utilization or combustion of the gases.

In FIG. 6, a further deposit is shown in a schematic representation, which shows by way of example four storage containers, which are grouped into two groups, each with two storage containers. Each group of two storage containers is a vaporizer reservoir 15a, 15b, which is connected to the Dämompeitungen 14 assigned. In order to use, if necessary, the volume of the two vapor expansion tanks 15a, 15b for both groups of storage containers, these are connected to each other via a vapors compensation line 35, into which a pressure booster 29 with an associated bypass line 31 and the shut-off valves 30 and the other shut-off valve 32, similar to the arrangement of Figure 5, which is associated with the upper storage container is inserted. Via this booster blower 29, vapors from the low-pressure vaporizing surge tank 15a to the higher-pressure vaporizing surge tank 15b are conveyed according to the requirements. In this way, the gas pressures in the vapor equalizing tanks 15a and 15b can be adjusted to the possible gas pressures in the gas spaces 4 of the different own weight storage tanks of the respective floating covers 5, 5a, 5b, 5c, so that the required exchange of product Steaming can be done automatically and without risks to the respective storage containers and floating covers.

In Fig. 6, a further construction of a lightweight floating ceiling in the container 1 b is shown. It is a floating cover made of GRP plastic, with a basis weight of 150 - 200 N / m ² (15 - 20 Kp / m ² ). All of the floating covers shown in Fig. 6 have a different basis weight, resulting in the different dimensions of the gas pressures in the damper accumulators 15a and 15b. The floating roof in the container 1 may have basis weights between 600 and 1000 N / m ² (60 and 100 Kp / m ² ). The internal floating ceiling in the container 1a may have basis weights between 400 and 600 N / m ² (40 and 60 Kp / m ² ). The lightweight aluminum swimming blanket in the container 1c has only a basis weight below 100 N / m ² (10 Kp / m ² ) and thus can not produce high gas pressure under the floating blanket. In the construction of FIG. 6, it is sufficient to associate only one of the two vaporizer reservoirs 15 with a gas utilization / gas combustion device 34.

FIG. 6 shows a rinsing liquid container 36 common to all storage containers, from which, after emptying a storage container 1, 1a, 1b, 1c, a suitable rinsing liquid (water, heating oil, diesel, middle distillate, slop, etc.) enters the space 4 under the floating cover 5, 5a, 5b, 5c, whereby the vapors in the space 4 are forced into a vaporizer tank 15, 15a. Subsequently, the valve 33 is closed and the vent valve 41 is opened at the outlet of the container and the rinsing liquid is pumped back into the rinsing liquid container 36. The reference numerals 37, 38, 39 and 40, a pump 37, bypass lines 38 and valves 39 and 40 are shown, with which the flushing liquid can be conveyed in different directions with appropriate switching of the valves. When the valves 39 are opened and the valves 40 are closed, the rinsing liquid is conveyed to the storage containers 1, 1a, 1b, 1c, and when the valves 40 are opened and the valves 39 are closed, the rinsing liquid is conveyed back to the rinsing liquid container. The flushing of the spaces 4 under the floating cover 5, 5a, 5b, 5c saves the camp operator the costly and time-consuming liberation of the rooms 4 of combustible and hazardous vapors before inspections and repairs in the rooms 4 under the floating cover.

Claims

claims

1. A storage facility for the storage of volatile hydrocarbons with at least one vertical round container, which is equipped with a liquid surface covering, floating cover in the form of a floating roof or a floating cover, wherein an educated between the cover and container wall annulus is sealed by means of flexible sealing elements and wherein the cover fittings for automatic control of the pressure and the negative pressure in the space below the cover are integrated, characterized in that the fittings (12, 13) of the at least one round container (1) to a Dämübeitung (14) are connected to the upper End is led out of the container and in turn connected to a separate vaporizer reservoir (15), wherein the circular container (1) and the vapor expansion tank (15) form a closed system.

2. Deposit according to claim 1, characterized in that the Dämperneitung (14) within the round container (1) has a vertically extending portion which is formed as a bellows (6) and in dependence of the floating height of the floating cover (5) expands or contracted.

3. Storage according to claim 2, characterized in that the bellows (16) surrounds a fixed support (17) and that the bellows (16) at the upper end of the support (17) is attached.

4. Deposit according to claim 3, characterized in that the carrier (17) is designed as sampling, Peil-, measuring and / or guide tube or as a roof support.

5. Deposit according to claim 1, characterized in that the Dämperneitung (14) within the round container (1) along a roller guide (27) is guided.

6. Deposit according to one of claims 1 to 5, characterized in that the vapors expansion tank (15) includes a flexible membrane (21) having a ballast weight (22) acting thereon.

7. Deposit according to one of claims 1 to 7, characterized in that Vapor utilization and / or Vampfverbrennungseinrichtungen (34) are connected to the vapors expansion tank (15).

8. Deposit according to one of claims 1 to 8, characterized in that a plurality of storage containers (1) to a common vapors expansion tank (15) are connected.

9. Deposit according to one of claims 1 to 9, characterized in that the vapors-compensating tank (15) with its ballast weight (22), taking into account the flow resistance of the Dämperneitung (14) is designed so that it has a negative pressure in the space (4 ) below the cover (5) by supplying vapors into this space (4) in the required amount and time, and designed to avoid a given overpressure in this space (4) below the cover (5) by: it absorbs vapors in the required amount and time from the room (4).

10. Deposit according to one of claims 1 to 8, characterized in that in the Dämperneitung (14) a derivative of the vapors to the vapors expansion tank (15) supporting the blower (29) is arranged, which via pressure sensors in the container (1). is controlled below the floating cover (5).

11. Deposit according to one of claims 1 to 11, characterized in that a plurality of storage containers (1) are divided into at least two groups according to their on the floating cover (5, 5a, 5b, 5c) pressure exerted on the liquid that each group associated with a pressure equalization tank (15a, 15b) and that various vaporizer reservoirs (15a, 15b) are connected via a vapor equalizing line (35) into which a booster blower (29) for delivering vapors from the low pressure vaporizing surge tank (15a) to the vaporizing surge tank (15b) Pressure is inserted.

12. Deposit according to one of claims 1 to 12, characterized in that in the lowest position of the floating cover (5) of the round container (1) between the floating cover (5) and the container bottom (2) remaining space (4) a rinsing liquid container (36) is connected and in the remaining space (4) after emptying of the container (1) existing hydrocarbon vapors are discharged by introducing the rinsing liquid in the space (4) to the vapors expansion tank (15).

13. Deposit according to claim 13, characterized in that as rinsing liquid water or storage liquids with low vapor pressure from other storage containers (1) of the deposit can be used.