6 replies to this topic

[alan8888]

Hi everyone ,need a little help here.

Currenly I have some diesel oil which has around 3000+ppm and I want to improve it under 500 ppm. I have heard that with those high presure and temp with hydrotreating staff can easily improve the ppm. But I doesn't want to use it. I read about the article using the alkali metal like sodium can remove the sulfur from the diesel. And those sodium product factory can give me free sodium waste which is alkali metal waste. I can use this waste to remove the sulfur.

1. Anyone have experience with this thing ? My plan is using all the cheapest product and free staff to improve the ppm.
2. Someone give me thise sodum treatment instrucsion please!!!
3. How many sodium I should add to the diesel for the Desulfurization process?
4. How long will the reaction take?
5. Do I need to use some kind of separator to remove those sodum from the diesel. And what separator is that.

The machine I currenly have , a mixer , a filter separator and a heater can increase heat to couple hundred degree

I am a newbie here and want to learn more
Thank You
If anyone can answer my question.

[herrani]

Hi Alan

I am not an expert in the matter, but I have been working with hydrotreating in our refinery for some time. I might not be 100% correct in the recommendation, but I believe that it goes in the right direction.

We used a caustic treatment to reduce the sulphur content in our naphtha stream until some years ago, but we didn't have such high sulphur concentrations. We had to install a hydrotreater in order to produce low sulfur gasoline, but I can see that you do not need to meet that specification.

You need some detailed process study from a well-known vendor before you can implement this solution, but I guess that you are just looking around to see what are your options.

You can remove sulfur from the diesel with the following reactions:

H2S + 2NaOH = Na2S + 2H2O
RSH + NaOH = NaSR + H2O

(where R stands for a hydrocarbon chain)

These reactions will take place in the caustic (water) phase, which you then need to separate from your diesel stream. The spent caustic can be regenerated by oxidation, where you will convert NaSR to RSSR. This is more soluble in hydrocarbons than in water.

The reaction is quite fast, but I believe that your problem will be in separating (typical liquid/liquid separator, based on density difference) the spent caustic from the diesel.

You will need much more equipment than what you have, including new separation vessels, reactors, pumps, air compressor, etc. and probably will need to use some form of catalyst for the oxidation reaction. How much diesel do you need to process in your plant?

It could be interesting to use alkali waste from a nearby industry, but probably it will not be a good idea. You need to consider other contaminants that might come with that stream (metals, salt, heavy components/wax, others?) which will have an impact on your diesel product quality, which could easily go offspec.

If you do not have a waste water treatment plant, or if it has a limited capacity, you will also need to consider that.

I hope you find this helpful!

[Zauberberg]

Sulfur compounds that can be removed by Caustic, are H2S and Mercaptans. Caustic is useless in process of removing other Sulfur compounds (such as Thiophene and its derivatives) normally present in various refinery cuts, e.g. Diesel, Heavy Gas Oil etc. High-pressure Hydrotreating is still the only commercial technology available on a large, industrial scale, used for distillate de-sulfurization.

[alan8888]

Hi Alan

I am not an expert in the matter, but I have been working with hydrotreating in our refinery for some time. I might not be 100% correct in the recommendation, but I believe that it goes in the right direction.

We used a caustic treatment to reduce the sulphur content in our naphtha stream until some years ago, but we didn't have such high sulphur concentrations. We had to install a hydrotreater in order to produce low sulfur gasoline, but I can see that you do not need to meet that specification.

You need some detailed process study from a well-known vendor before you can implement this solution, but I guess that you are just looking around to see what are your options.

You can remove sulfur from the diesel with the following reactions:

H2S + 2NaOH = Na2S + 2H2O
RSH + NaOH = NaSR + H2O

(where R stands for a hydrocarbon chain)

These reactions will take place in the caustic (water) phase, which you then need to separate from your diesel stream. The spent caustic can be regenerated by oxidation, where you will convert NaSR to RSSR. This is more soluble in hydrocarbons than in water.

The reaction is quite fast, but I believe that your problem will be in separating (typical liquid/liquid separator, based on density difference) the spent caustic from the diesel.

You will need much more equipment than what you have, including new separation vessels, reactors, pumps, air compressor, etc. and probably will need to use some form of catalyst for the oxidation reaction. How much diesel do you need to process in your plant?

It could be interesting to use alkali waste from a nearby industry, but probably it will not be a good idea. You need to consider other contaminants that might come with that stream (metals, salt, heavy components/wax, others?) which will have an impact on your diesel product quality, which could easily go offspec.

If you do not have a waste water treatment plant, or if it has a limited capacity, you will also need to consider that.

I hope you find this helpful!

Hi Herrani,

Thx for the reply. I am a newbie in these diesel fuel.
Yes Herrani I am just looking around to see what kind of solution can have the lowest budget. My solution is not for a big factory it is just very small one. The place I work in here for the sulfur standard is 2000ppm for the any place other the cities, inside the cities got to be under 500ppm.
We got the diesel supply from the big factory left over in low price,so we try to desulfurization and resell to someone. The first thing I need to do is get the diesel get under 2000ppm, once i get this done we will move forward to 500ppm. Hydrotreating will be next to plan to work on.
I am planning to use the alklin waste, but you are right, i did not consider the stream problem that will cause problem. I really need to think about the stream problem. For the left over waste we use to hire some other company to take care the waste for us.

So is the separation vessels you recommand for remove the sodium from the diesel ? I can get a small one in local to test it.. Machine is cheap in here.

[alan8888]

Sulfur compounds that can be removed by Caustic, are H2S and Mercaptans. Caustic is useless in process of removing other Sulfur compounds (such as Thiophene and its derivatives) normally present in various refinery cuts, e.g. Diesel, Heavy Gas Oil etc. High-pressure Hydrotreating is still the only commercial technology available on a large, industrial scale, used for distillate de-sulfurization.

Hi Zauberberg,

Can you tell me more about . this:
Caustic is useless in process of removing other Sulfur compounds (such as Thiophene and its derivatives) normally present in various refinery

So without other cytalyis , I am just adding the sodium , is this correct. ?
If someone can tell me the ratio I should out in will be great :-D. But I think i need to test it by myself. Separate with the diesel is also a problem for me

thank you

[gvdlans]

Hello Allan,

So what you seem to propose is to mix two waste streams (high sulfur Diesel and a sodium waste) and make a valuable product (low sulfur Diesel). That sounds too good to be true...

What Zauberberg tried to explain is that a caustic treatment will only remove some sulfur components (H2S and mercaptans), but will not remove the sulfur components in your Diesel such as thiophens and its derivates. So by mixing up your waste streams you end up with a bigger waste stream.

An example of a caustic treatment process is the Merox process, see for example http://en.citizendium.org/wiki/Merox

Note that the word "caustic" is used here for a solution of sodium hydroxide (NaOH) in water. You are writing about "sodium", which is something different. Sodium is a metal.

As Zauberberg already wrote, Diesel desulfurization is normally done in refineries with the high pressure hydrotreatment process. Here the distillate stream is mixed with hydrogen and sent to a reactor filled with catalyst where the sulfur compounds react with hydrogen to form H2S. See for example: http://en.citizendiu...desulfurization
A hydrotreatment plant requires expensive equipment such as compressors, reactor, distillation column as well as a hydrogen source.

Edited by gvdlans, 21 October 2010 - 10:07 AM.

[Qalander (Chem)]

Hello Allan,

So what you seem to propose is to mix two waste streams (high sulfur Diesel and a sodium waste) and make a valuable product (low sulfur Diesel). That sounds too good to be true...

What Zauberberg tried to explain is that a caustic treatment will only remove some sulfur components (H2S and mercaptans), but will not remove the sulfur components in your Diesel such as thiophens and its derivates. So by mixing up your waste streams you end up with a bigger waste stream.

An example of a caustic treatment process is the Merox process, see for example http://en.citizendium.org/wiki/Merox

Note that the word "caustic" is used here for a solution of sodium hydroxide (NaOH) in water. You are writing about "sodium", which is something different. Sodium is a metal.

As Zauberberg already wrote, Diesel desulfurization is normally done in refineries with the high pressure hydrotreatment process. Here the distillate stream is mixed with hydrogen and sent to a reactor filled with catalyst where the sulfur compounds react with hydrogen to form H2S. See for example: http://en.citizendiu...desulfurization
A hydrotreatment plant requires expensive equipment such as compressors, reactor, distillation column as well as a hydrogen source.

Dear
Above you've got very good/penitent, specific replies from some of our forum greats(as I consider them) Friendly yet Grand professional personalities.

I add my wild thought ideas as usual but you must realize that Quality improve carries a cost always;and not that simple as you consider.

• If their exist some sulfur or nitrogen heterogeneous ring compounds
• furfural solvent extraction may serve useful
• normally practiced for lube base oils quality improvements
• that included extraction and removal of sulfur& Nitrogen etc. undesirables

Hope this shows another avenue at-least theoretically,may not prove economically viable.