DD215117A1 - PROTECTION UNIT FOR ROOF COVERS AND CONSTRUCTION WORK - Google Patents

Abstract

The aim of the invention is the performance of roofing and plumbing work in solid rafters cardboard and similar roofs up to 10% roof pitch, without significant road closure and much lower Geruestmaterialeinsatz. The protective framework secures the working colleagues in the eaves area and prevents falling objects, such as tools, equipment and building materials. Two triangular frames are pre-assembled on the roof surface and placed vertically on the base points. In the cantilever area, both triangular frames are coupled with a rectangular frame (5000 mm x 1200 mm). The rear feet are connected with 5 pieces of steel tube.

Description

-1- Z50 334

Title of the invention

Method for removing oxygen from water

Field of application of the invention

The invention relates to a process for the removal of oxygen dissolved in water using activated hydrazine, wherein the hydrazine is activated by addition of complexes of trivalent cobalt with inorganic ligands as a complexing agent. Activated hydrazine is used to remove oxygen from water at low temperatures to ensure effective corrosion protection of boilers, tanks, pipelines and heat exchangers, for example in cooling circuits.

Characteristic of the known technical solutions

Activated hydrazine is preferably used to remove oxygen dissolved in water, which, with the use of suitable activators and co-activators, reacts with even oxygen dissolved in water at low temperatures to form harmless nitrogen. In general, organic compounds are used as activators, but have the disadvantage that they can go into the vapor phase. This behavior is for special use cases, eg. B. Further use of the vapor in catalytic process stages, not desirable. Cationic and anionic complexes of trivalent cobalt with inorganic ligands as complex formation have been proposed as particularly suitable activators (WPC 23 F / 224246). Although these activators are to be regarded as favorable, there is still the disadvantage that such an activated hydrazine does not reach its full reaction rate with respect to dissolved oxygen in water from the beginning. It has now been proposed to eliminate this deficiency either by gasification with air (WPC 23 F / 224247) or by addition of trivalent phenols (WPC 23 F / 227201) or 2-amino-4-nitrophenol WPC 23 F / 239217) as co-activators , While in the use of said co-activators, in turn, organic compounds are contained in the water, satisfactory degradation rates of the dissolved oxygen in water can be achieved only by using relatively high activator concentrations by air fumigation of the activated hydrazine.

Object of the invention

The aim of the present invention is the rapid removal of dissolved oxygen in water using hydrazine which has been activated with complexes of trivalent cobalt with inorganic ligands as complexing agents in low concentration without organic co-activators.

Explanation of the essence of the invention

It was therefore an object to develop a suitable method which ensures that hydrazine solutions which are provided with said activators in low concentration, a high reaction rate to water dissolved in oxygen immediately reach, with a fumigation with air and the use organic coactivators can be dispensed with.

This object is achieved in accordance with the invention by adding hydrogen peroxide or adducts of the hydrogen peroxide to the oxygen-containing water before the addition of activated hydrazine. Surprisingly, it has been found that hydrazine solutions which have been activated with complexes of trivalent cobalt with inorganic ligands as complexing agents and are free of organic co-activators react at high speed with oxygen dissolved in water, if the oxygen-containing water prior to addition of the activated hydrazine small amounts of hydrogen peroxide or Adducts are added to the hydrogen peroxide. The concentration of the activator in the hydrazine can be kept low and 0.1 percent by weight based on the aqueous hydrazine solution with 220g N ₂ H ₄ /! below. Good results are achieved when the activator content is in the range of 0.25 to 0.5 g / l of aqueous hydrazine solution. Preference is given to using sodium hexanitritocobaltate (III). High rates of degradation of dissolved oxygen in the water are achieved when 10 to 110 mg / l of hydrogen peroxide or adducts of hydrogen peroxide, for example carbamide peroxide, are added to the water.

Embodiment - -

To oxygen-containing water with about 6.5 mg O ₂ / l, whose pH had been adjusted to 10.4, hydrogen peroxide or carbamide peroxide are added in amounts of 10 to 110 mg / l. To this solution is added 1 ml of aqueous hydrazine solution containing 220 g of hydrazine per liter, which has been activated with 0.25 to 0.5 g / l of sodium hexanitritocobaltate (III). Oxygen depletion is measured at a temperature of 293K. The following table shows the percentage of oxygen reduction after a reaction time of 10 minutes and compared with values obtained without the addition of hydrogen peroxide or carbamide peroxide.

Content of Na ₃ CO (NOu) ₆ content of H ₂ O ₂ content of Car O ₂ degradation

in the hydrazine (g / l) in the O ₂ -containing bamidperoxid nachiOmin

Water (mg / l) imO ₂ -containing (%)

Water (mg / 1)

0,5 - - 35

0.5 -20-99

0.5 - 10 93

0.5 - 50 99

0.25 - · - 30

0.25 20 - 80

0.25 110 - 93

0.25 - 100 97

Claims (2)

-2- 250 334 5 invention claims A process for the removal of oxygen from water using activated hydrazine activated by complexes of trivalent cobalt with inorganic ligands as a complexing agent, characterized in that hydrogen peroxide or adducts of hydrogen peroxide are added to the oxygenated water prior to the addition of activated hydrazine. 2. The method according to item!, Characterized in that the hydrazine solution contains 0.25 to 0.5 g / l Natriumhexanitritocobaltat (III) as an activator and the oxygenated water 10 to 110mg / l of hydrogen peroxide or carbamide peroxide are added.