JPH0757349B2 - Method and apparatus for treating liquid containing hydrogen sulfide - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method and apparatus for treating a hydrogen sulfide-containing liquid, which effectively treats hydrogen sulfide-containing wastewater generated in an oil refining plant or a chemical plant. It is a thing.

<Prior art> Oil refineries and chemical plants generate waste liquid containing hydrogen sulfide. Since this waste liquid is a source of pollution that is harmful to humans and activated sludge in waste liquid treatment facilities and produces a foul odor, the hydrogen sulfide component contained in the liquid must be decomposed.

When the amount of hydrogen sulfide-containing waste liquid generated in the factory is small, or when the concentration of hydrogen sulfide contained is low, the hydrogen sulfide component can be decomposed relatively easily. However, if a large amount of hydrogen sulfide-containing waste liquid is continuously generated from the factory or if the waste liquid contains a high concentration of hydrogen sulfide component, the amount exceeding the treatment capacity may be temporarily reduced in an empty oil tank, for example. Store in. Then, the waste liquid accumulated in this oil tank is treated at a later date, but since an amount of the waste liquid exceeding the treatment capacity is stored in the oil tank on a daily basis, an extremely large-scale storage tank is required. May cause pollution.

Therefore, as a conventionally known treatment method for hydrogen sulfide in a liquid, there is a treatment method in which hydrogen peroxide is reacted in a range of an alkaline range to change into a harmless neutral salt.

<Problems to be Solved by the Invention> However, the above processing method has many problems.

That is, hydrogen peroxide is consumed not only by hydrogen sulfide but also by organic substances existing in the same liquid, so that the consumption amount increases and the amount of chemical agent used during processing increases, which is economical. The burden is heavy. Further, hydrogen peroxide is decomposed to generate oxygen, and therefore, when used in a liquid containing a flammable substance such as oil, there is a risk of burning or explosion, which is not preferable. In addition, when treating liquids with the above risks, if the storage tank itself is made part of the liquid circulation path, the above-mentioned risk will be involved.Therefore, a small treatment tank should be installed separately from the storage tank. , It is necessary to process waste liquid from a storage tank while dividing it into a fixed amount of tanks.

Therefore, it is not possible to process all the waste liquids to be treated in a batch and continuously, so that not only a great deal of time and man-hours are required for the treatment, but also it is necessary to measure the concentration and the basis weight of the chemical agent for each tank. However, the processing work becomes extremely complicated.

<Means for Solving the Problems> The present invention has been proposed in view of the above, and a liquid circulation path is provided outside the storage tank for the liquid containing sulfide water and the liquid injection device is exposed inside the storage tank. A ferrous sulfate solution is supplied to the liquid circulation path to convert hydrogen sulfide into iron sulfide, and the liquid circulated while precipitating and separating is injected into the storage tank. Regarding the treatment method and its equipment, the amount of chemical agent used can be reduced by the above configuration, and the hydrogen sulfide treatment can be achieved by improving safety, simplifying treatment work, shortening the work period, etc. Is intended to be a comprehensive improvement of.

<Examples> Examples of the present invention will be described below.

The present invention relates to a treatment method in which a ferrous sulfate solution is supplied to a liquid containing hydrogen sulfide, the hydrogen sulfide is changed to iron sulfide to cause precipitation separation, and a treatment apparatus for carrying out this treatment method. It is a thing.

The drawings show the outline of the above-described processing apparatus, and a case where, for example, an empty crude oil tank is used as the storage tank 1 for temporarily storing the liquid containing hydrogen sulfide will be described.

The above-mentioned liquid storage tank 1 containing hydrogen sulfide has an open upper surface,
Inside the storage tank 1, a floating roof 2 that floats on the surface of the internal liquid is provided.

A liquid circulation path 3 for circulating the liquid in the storage tank 1 is installed outside the storage tank 1 described above.

The liquid circulation path 3 has a valve-equipped outflow pipe 4 for discharging the liquid in the storage tank 1, a suction device 5 for sucking the liquid in the storage tank 1 by the outflow pipe 4, and a tip extending from the suction device 5 and having a tip end of the storage tank. 1 and an inflow pipe 6 facing inside.

The inside of the suction device 5 described above is partitioned by a partition plate or steel material 7 to form a first chamber 8 and a second chamber 9, and a suction pump (not shown) is connected to keep a constant depressurized state. The outflow pipe 4 is connected to the first chamber 8 and the inflow pipe 6 is connected to the second chamber 9.

A circulation pump 10 is provided in the inflow pipe 6 and a sampling mechanism 11 is provided between the suction device 5 and the circulation pump 10.
A PH value measuring mechanism 12 and a ferrous sulfide supply mechanism 1 are provided. The sampling mechanism 11 is for collecting the liquid flowing out from the suction device 5 to detect the state of the hydrogen sulfide component, and the PH value measuring mechanism 12 is for measuring the liquid flowing out from the suction device 5.
It is for measuring PH. Further, the supply mechanism 13 is provided with an injection pump 16 in the middle of an injection pipe 15 extending from the ferrous sulfate solution tank 14, a flow meter 17 and a valve 18 are provided in front of the injection pipe 15, and the tip portion is a suction device. 5 is connected to the inflow pipe 6 between the circulation pump 10.

An inflow pipe 6 between the circulation pump 10 and the storage tank 1 is provided with an alkaline liquid supply mechanism 19, a PH value measuring mechanism 20, and a sampling mechanism 21.

The alkaline liquid supply mechanism 19 is connected to the inflow pipe 6 by providing an alkaline injection pump 24, a flow meter 25 and an opening / closing valve at an appropriate position in the middle of the alkaline liquid injection pipe 23 extending from the alkaline liquid tank 22. This is because the PH value measuring mechanism 20 measures the PH value of the liquid passing through the inflow pipe 6, and the sampling mechanism 21 collects the liquid passing through the inflow pipe 6 to detect the state of the hydrogen sulfide component. A recorder 26 is connected to the PH value measuring mechanism 20 and the PH value measuring mechanism 12 described above, and the measured values of the PH value measuring mechanism 12 and the PH value measuring mechanism 20 are intermittently young or continuous. Can be recorded and printed on.

The distal end of the inflow pipe 6 described above is branched into a plurality of parts, and each branched part is passed through, for example, a post opening (not shown) provided in the floating roof 2 to project into the inside of the storage tank 1.
Connect to. When each liquid jetting device 27 jets the liquid from the inflow pipe 6, the tip end thereof is freely rotated by the jetting pressure to stir the liquid in the storage tank 1.

The treatment apparatus of the present invention has the above-mentioned configuration, and the liquid containing hydrogen sulfide is stored in the storage tank 1.

In order to process the hydrogen sulfide component of this liquid, the suction device 5 is depressurized to cause the liquid in the storage tank 1 to flow into the suction device 5 through the outflow pipe 4. In this case, in the suction device 5, the liquid from the outflow pipe 4 flows into the first chamber 8, and the fine solid components contained in this liquid settle below the first chamber 8 and the partition plate 7 is removed. The liquid that has passed over or passed through the steel material is in the second chamber 9
Collect in.

The liquid accumulated in the second chamber 9 flows into the inflow pipe 6 by the action of the circulation pump 10, and is sampled by the sampling mechanism 11 in the middle of the injection pump 16 or the PH value is measured by the PH value measuring mechanism 12. Then, in front of the circulation pump 10, the supply mechanism 13
As a result, the ferrous sulfate solution is injected, and behind the circulation pump 10, the alkaline solution supply mechanism 19 injects the alkaline solution. Furthermore, behind the circulation pump, the PH value measuring mechanism 20
The PH value is measured again and is sampled by the sampling mechanism 21 and then injected into the storage tank 1 by the liquid injection device 27 to be sufficiently mixed and stirred with the liquid in the storage tank 1.

Therefore, the liquid circulation path 3 circulates the liquid in the storage tank 1,
The supply mechanism 13 supplies the ferrous sulfate solution and the alkaline solution in the middle of the circulation flow. Then, a hydrogen sulfide-containing liquid containing ferrous sulfate and an alkaline solution is sprayed into the storage tank 1 by the liquid spraying device 27 to sufficiently stir and mix the internal liquid, and the hydrogen sulfide component and ferrous sulfate in an alkaline state are mixed. Reacts with and changes to solid iron sulfide.
Or the bottom of the suction device 5.

Therefore, each sampling mechanism 11, 21 and PH value measurement mechanism
Analyze the hydrogen sulfide concentration of the circulating liquid by 12, 20
The pH value may be measured to check the treatment state of the liquid in the storage tank 1, and when the liquid is sufficiently treated, the liquid in the storage tank 1 or the suction device 5 may be discharged to discharge the solid iron sulfide accumulated at the bottom.

<Effects of the Invention> As is clear from the above, according to the present invention, the ferrous sulfate solution was supplied to the liquid containing hydrogen sulfide, and the hydrogen sulfide was changed to iron sulfide for precipitation separation. It is only necessary to use a ferrous sulfate solution as a chemical agent for treating a liquid containing hydrogen sulphide, the amount of this solution used can be significantly reduced. Further, even a liquid containing hydrogen sulfide can be continuously and rapidly processed, the processing period can be extremely shortened, and the processing work is simple. Further, in the present invention, since the liquid circulation path is provided outside the storage tank and the liquid injection device is exposed to the inside of the storage tank to inject the circulated liquid into the storage tank, the liquid retained at the bottom of the storage tank The solid content can be sufficiently mixed and stirred. Therefore, the storage tank can be cleaned at the same time. Furthermore, there is no risk of combustion or explosion even if the storage tank for the liquid containing hydrogen sulfide is used as it is, and it has practical value as a waste liquid treatment especially in a factory that generates a large amount of waste liquid containing high concentration of hydrogen sulfide. Is extremely high.

[Brief description of drawings]

 The drawing is a schematic view showing an embodiment of the apparatus of the present invention.

Claims (2)

[Claims] 1. A liquid circulation path is provided outside a storage tank for a liquid containing hydrogen sulfide, and a liquid injection device is exposed to the inside of the storage tank, and a ferrous sulfate solution is supplied to the liquid circulation path to supply hydrogen sulfide. A method for treating a hydrogen sulfide-containing liquid, characterized in that a liquid that is changed into iron sulfide and is circulated while precipitating and separating is injected into a storage tank. 2. A storage tank for a liquid containing hydrogen sulfide, and a liquid circulation passage provided outside the storage tank, the liquid circulation passage being located outside the storage tank, a pipe, and a pipe. A treatment device for hydrogen sulfide-containing liquid, comprising a liquid injection device connected to the inside of the storage tank and facing the inside of the storage tank, and a ferrous sulfate supply mechanism.