METHOD FOR DETECTING AND PREVENTING LEAKS

Abstract

A method for detecting and preventing leaks of a double-walled container for the storage of poisonous, caustic, irritant and/or combustible media utilizes a double-walled container with an inner wall and an outer wall. A cavity is formed between the inner wall and the outer wall, a positive pressure is generated in the cavity, and in the event of a leak of the inner wall, a gas is fed to the cavity in order to maintain a positive pressure in the cavity. A container system includes an open-loop/closed-loop control device for the open-loop/closed-loop control of a gas throughflow in a line. The system includes a pressure measuring unit for measuring the pressure in the cavity of the double-walled container.

Claims

1-15. (canceled)

16. A method for detecting and preventing leaks in a double-walled container for the storage of poisonous, caustic, irritant and/or combustible media, wherein the double-walled container has an inner wall and an outer wall, wherein a cavity is formed between the inner wall and the outer wall, wherein a positive pressure is generated in the cavity, and wherein a gas is supplied to the cavity if the inner wall springs a leak in order to maintain a positive pressure in the cavity, wherein the positive pressure in the cavity is measured and the pressure and/or the throughflow of the gas being supplied to the cavity is controlled in such a way that the positive pressure in the cavity referred to the pressure in the interior of the double-walled container lies between 5 mbar and 50 mbar.

17. The method according to claim 16, wherein at least one gas, preferably at least one gas and at least one liquid, is supplied to the container.

18. The method according to claim 17, wherein the positive pressure in the cavity is measured, preferably by measuring the pressure of the gas being supplied to the double-walled container and measuring the pressure of the gas being supplied to the cavity, as well as calculating the difference between these two pressures.

19. The method according to claim 16, wherein the pressure and/or the throughflow of the gas being supplied to the cavity is controlled in such a way that the positive pressure in the cavity referred to the pressure in the interior of the double-walled container lies between 10 mbar and 30 mbar.

20. The method according to claim 16, wherein a liquid stored in the double-walled container, which escapes from this container due to a leak in the inner wall and accumulates in the cavity, is conveyed into a monitoring container via a drainage line at the lowest point of the cavity, wherein the monitoring container is partially filled with another liquid, preferably water, particularly fully desalinated water or softened industrial water.

21. The method according to claim 20, wherein the filling level and/or the temperature and/or the conductivity of the liquid in the monitoring container is measured in order to detect leaks in the double-walled container.

22. The method according to claim 20, wherein an alarm is triggered once a predefined limiting value of the filling level and/or the temperature and/or the conductivity of the liquid in the monitoring container is reached.

23. The method according to claim 20, wherein the monitoring container is emptied into another container, preferably an Intermediate Bulk Container (IBC), via a bottom drainage valve once the filling level of the liquid in the monitoring container reaches a limiting value.

24. A container system for the storage of poisonous, caustic, irritant and/or combustible media, comprising: a double-walled container having an inner wall and an outer wall, wherein a cavity is formed between the inner wall and the outer wall; wherein it comprises the following: a compressor, preferably a side channel blower; a line that is provided for conveying a gas and serves for connecting the outer wall to the compressor; an open-loop/closed-loop control device, preferably a control valve, particularly a bypass control valve, for the open-loop/closed-loop control of a gas throughflow in the line in such a way that the positive pressure in the cavity referred to the pressure in the interior of the double-walled container lies between 5 mbar and 50 mbar; and a pressure measuring unit for measuring the pressure in the cavity of the double-walled container.

25. The container system according to claim 24, characterized by a monitoring container that is connected to the lowest point of the cavity of the double-walled container.

26. The container system according to claim 24, characterized by a flow meter (10) for measuring the flow rate of the gas being supplied to the cavity (5) of the double-walled container (2).

27. The container system according to claim 24, wherein the monitoring container has a measuring device, particularly a radar measuring device, for measuring the filling level.

28. The container system according to claim 24, wherein the monitoring container has a conductivity sensor and/or a temperature sensor, wherein a multi-parameter transmitter preferably is provided for evaluating the measurement of the conductivity and/or the temperature.

29. The container system according to claim 24, wherein the inner wall and the outer wall of the double-walled container are lined with a barrier layer, which preferably consists of a perfluoroalkoxy polymer (PFA).

30. The utilization of the double-walled container of the container system according to claim 24 as an acid condenser trough in a desulfurization process, preferably a Wet-Sulfuric-Acid (WSA) process.

Description

[0034] The invention is described in greater detail below with reference to the nonrestrictive exemplary embodiment illustrated in the drawing.

[0035] FIG. 1 shows a flow chart of an inventive container system, in which leaks in a double-walled container are detected and prevented.

[0036] FIG. 1 shows a flow chart of an inventive container system 1 that comprises a double-walled container 2. According to the embodiment shown, the double-wailed container 2 is used as an acid condenser trough in a Wet-Sulfuric-Acid (WSA) process. Sulfuric acid is produced in pipes, which are primarily aligned vertically and arranged in the acid condenser trough, with the aid of the WSA process known, for example, from DE 689 12 766 T2, in which sulfuric acid vapors condense and droplets of the sulfuric acid are collected in a special filter. In this case, gas containing sulfuric acid is supplied to the pipes from below at a temperature above the sulfuric acid dew point and cooled to a temperature, at which sulfuric acid condenses, while it flows upward in the pipes. Aerosol filters for separating the condensed sulfuric acid are fastened on the upper end of the pipes.

[0037] In the embodiment shown, the double-walled container 2 is a closed container that has an inner wall 3 and an outer wall 4, wherein a cavity 5 is formed between the inner wall 3 and the outer wall 4. The inner wall 3 and the outer wall 4 are lined with a barrier layer of a perfluoroalkoxy polymer (PFA) in order to increase the resistance to the liquid stored in the container 2, which at least partially consists of sulfuric acid.

[0038] In the embodiment shown, sulfur-containing waste gas is conveyed into the interior of the closed double-walled container 2 via a supply line 6 in order to condense sulfuric acid vapors in the container 2. A pressure measuring unit 7 measures the pressure of the supply line 6, wherein this pressure corresponds to the pressure in the interior of the container 2. Gas is supplied to the cavity 5 via a line 8 that is connected to the cavity 5 of the container 2. This gas is subjected to a positive pressure with the aid of a compressor, which is realized in the form of a side channel blower 9 and connected to the line 8. in addition, a flow meter 10 for measuring the flow rate and a pressure measuring unit 11 for measuring the pressure in the line 8 are arranged on the line 8. A differential pressure between the interior of the closed container 2 and the cavity 5 is determined with the aid of the pressure measurement in the supply line 6 by means of the pressure measuring unit 7 and the pressure measurement in the line 8 by means of the pressure measuring unit 11, wherein the signal of the determined differential pressure is transmitted to an open-loop/closed-loop control device, which is realized in the form of a bypass control valve 12 in the embodiment shown. During normal operation, a constant positive pressure of 20 mbar referred to the pressure in the interior of the container 2 is generated in the cavity 5 of the container 2 by means of the side channel blower 9 and the pressure control with the aid of the bypass control valve 12. The side channel blower 9 is also deactivated if no positive pressure relative to the surroundings exists in the interior of the container 2, e.g. when no sulfur-containing waste gas is supplied.

[0039] If the inner wall 3 springs a leak, gas flows from the cavity 5 into the interior of the container 2 such that the positive pressure in the cavity 5 drops. This causes the flow rate of the gas in the line 8 to increase, wherein this increase is detected with the aid of the flow meter 10 and an alarm is triggered. The pressure simultaneously drops in the line 8, wherein the bypass control valve 12 compensates this pressure drop.

[0040] In the embodiment shown, the double-walled container 2 has a drainage line 13 of polytetrafluoroethylene (PTFE) at the lowest point of the cavity 5. This drainage line 13 is connected to a monitoring container 14, which is filled to approximately 70%, with softened industrial water. The monitoring container 14 has a radar measuring device 15 for measuring the filling level of the liquid stored in the monitoring container 14. In addition to the radar measuring device 15, the monitoring container 14 also has a filling level limit indicator 16 for triggering an alarm once a limiting value of the filling level is reached. The monitoring container 14 in the embodiment shown furthermore has a conductivity sensor 17 and a temperature sensor 18 for respectively measuring the conductivity and the temperature of the liquid stored in the monitoring container 14. In order to ensure a reliable operation of the conductivity measurement, the last portion of the conductivity sensor 17, which is realized in the form of a probe in the embodiment shown, always has to be immersed in the liquid. The evaluation of the conductivity measurement and the temperature measurement is realized by means of a multi-parameter transmitter, which is not illustrated in FIG. 1.

[0041] If the inner wall 3 springs a leak in the embodiment shown, the liquid stored in the container 2, which at least partially consists of sulfuric acid, escapes through the leak and collects in the cavity 5, wherein the liquid flows to the lowest point of the cavity 5 under the influence of the gravitational force. The liquid is at the lowest point conveyed into the monitoring container 14 via the drainage line 13, wherein the liquid intermixes with the softened industrial water stored in the monitoring container 14. Due to constant wall cooling of the monitoring container 14, the temperature of the softened industrial water stored therein amounts to approximately 30° C. Since the softened industrial water intermixes with the warmer liquid from the container 2 being conveyed into the monitoring container 14, the temperature of the liquid mixture in the monitoring container 14 increases. This temperature increase is measured with the aid of the temperature sensor 18 and a corresponding signal is transmitted to the multi-parameter transmitter. The multi-parameter transmitter evaluates the signal of the temperature increase and triggers an alarm once the temperature of the liquid in the monitoring container 14 reaches 50° C.

[0042] Intermixing of the softened industrial water with the liquid from the container 2 not only causes the temperature of the liquid mixture to change, but also its conductivity. This conductivity change is measured with the aid of the conductivity sensor 17 and a corresponding signal is transmitted to the multi-parameter transmitter. The multi-parameter transmitter evaluates the signal of the conductivity increase and likewise triggers an alarm.

[0043] The liquid being conveyed into the monitoring container 14 causes the filling level of the liquid mixture stored in the monitoring container 14 to rise, wherein the rise of the filling level is measured by the radar measuring device 15 and a corresponding signal is transmitted to a device for evaluating the measurement. The rise of the filling level makes it possible to detect a leak in the inner wall 3 of the container 2 such that measures required in response to a leak in the inner wall 3 can be taken in a timely manner. The filling level limit indicator 16 triggers an alarm once the filling level of the liquid amounts to approximately 90% of the height of the internal volume of the monitoring container 14. When the alarm is triggered, the monitoring container 14 is emptied into an intermediate Bulk Container (IBC) 19 arranged underneath the monitoring container 14 via a bottom drainage valve 20 in order to prevent the liquid escaping from the container 2, which is conveyed into the monitoring container 14, from coming in contact with the environment.