Selecting compatible material for hydrogen peroxide facilities is the first step to be taken into consideration when you are in designing phase of the facilities. Because as I explained in my previous article “Factors That Affect Hydrogen Peroxide Decomposition”, compatible construction materials of pipe, pump and tank will keep hydrogen peroxide concentration stable.
Hydrogen peroxide handling facilities at least consists of pipe, hose, pump, valve, gasket (packing) and tank. In this post I just want to show you the best materials with which I have best experiences and good results, especially for long time storage.
- Pipe: choose stainless steel SUS 316 or SUS 304L or equivalent, TIG welding with Argon as the shielding gas.
- Hose: use reinforced-vinyl hose.
- Pump: choose material same as pipe material for hydrogen peroxide contacting parts, such as casing, impeller, etc.
- Valve: stainless steel SUS 316 or SUS 304L or equivalent, ball valve with disc hole, and valve seat made of Teflon.
- Gasket (packing): Teflon or viton.
- Tank: stainless steel SUS 304L or equivalent, TIG welding with Argon as the shielding gas.
For pipe, valve and tank required to be chemical cleaned and passivated before being filled by hydrogen peroxide. Later, in the next post I will explain about chemical cleaning procedure for hydrogen peroxide facilities.
Decomposition reaction of hydrogen peroxide is very vital factor that is needed to be understood clearly. Decomposition reaction does not only affect hydrogen peroxide quality (concentration), but also determine the safety.
As I explained in my previous post, about factors that affect hydrogen peroxide decomposition, one of those factors is the existence of heavy metal (as catalyst) in hydrogen peroxide solution. To help you get deep understanding about the process, a video on hydrogen peroxide decomposition will give you a clear visualization.
Below, I attach a video that shows hydrogen peroxide decomposition process releasing water, oxygen gas and heat.
I strongly recommend you to give enough attention to this post, because if you fail to avoid decomposition reaction to occur, you will not only lose your hydrogen peroxide (concentration decreases), but you may be exposed to some hazards. Remember, beside water hydrogen peroxide also releases oxygen and heat when decomposes.
Oxygen will develop high pressure in piping or vessel even it can introduce over pressure condition. Heat from the reaction will expose high temperature. Both sources of hazards if not treated properly may cause severe damage to equipments and threaten human safety.
Below are factors that affect hydrogen peroxide decomposition reaction. Read each point carefully.
- The presence of heavy metal (catalyst) such as Palladium (Pd), Platinum (Pt), Ferro (Fe), etc.
- Dirt and dust. Always keep clean area where hydrogen peroxide is stored, includes all handling facilities.
- Temperature. According to research results, every 10oC of temperature increase (in the range of 50~70oC) will cause the rate of decomposition reaction increases by factor 2.
- Using incompatible materials for its packaging material.
- pH. Increase in pH value of hydrogen peroxide solution will obviously increase decomposition reaction.
- The surface of storage containers. Rough surface or the presence of minutes scratches on shell side of the tank aids the decomposition process.
The easiest thing to do to avoid hydrogen peroxide decomposition is by separating hydrogen peroxide in the plant site from the incompatible materials as mentioned above.
One of our hydrogen peroxide customers called us because its hydrogen peroxide tank was getting hot. The hydrogen peroxide temperature inside the tank was 68oC. They don’t know what was happening.
Hydrogen peroxide in that tank was decomposing and releasing heat during the decomposition reaction. Below were things that we recommended them to do at the time.
- Filled demineralized water or purified water into the hydrogen peroxide tank in order to de-accelerate the decomposition reaction rate and cooled the temperature down.
- Did not drain out hydrogen peroxide from the tank until its concentration was determined.
- Took sample from the tank and measured its concentration.
- Monitored hydrogen peroxide temperature and its concentration in tank for several hours. If hydrogen peroxide temperature was down and concentration became stable, it meant the decomposition reaction had stopped. .
- If hydrogen peroxide temperature would not decrease or be stable, it meant the decomposition reaction was still in progress and we should let entire hydrogen peroxide decomposed. After that the entire hydrogen peroxide changed to water and could be drained out from the tank.
It becomes very important to equipped hydrogen peroxide tank with standard safety facilities and monitoring equipments. Once they installed, it will be easier to monitor and take actions when something wrong happens.
Please read my previous article about facilities of hydrogen peroxide storage tank, before you make your tank design or improve an installed one.
Recently, Researcher from Cardiff University and Lehigh University announced that a gold-palladium alloy catalyst had leaded to a successful direct production of hydrogen peroxide. The experiment showed very high selectivities of more than 95%, which are now comparable to the indirect process, and that makes a direct process a lot more feasible and viable.
The researchers believe that they have the solution to overcome hydrogen peroxide decomposition after being formed, as shown by the previous catalyst used in direct process of hydrogen peroxide. The process works by applying an acid pre-treatment to the carbon support before the gold-palladium alloy nanoparticles are placed on it, thus making smaller metal particles which can block the decomposition reaction.
The experiment results looked promising because the mainstream uses of hydrogen peroxide require concentration level of 3 to 8%. However, it is unclear whether the reaction can be scaled up to industrial scale.
Currently, hydrogen peroxide is industrially produced through indirect process that contains of hydrogenation and oxidation of anthraquinone.
Subscribe to:
Posts (Atom)
