We say that desalination is energy intensive.

I can’t help wondering how the energy required for other energy intensive processes compare with each other. For starters, how does the energy requirements for each of these energy intensive processes compare?

• Desalination of seawater
• Production of table salt by evaporation of seawater
• Production of liquid oxygen and nitrogen
• Electrolysis of water to get hydrogen
• Production of aluminium
• Production of lithium
• Production of magnesium
• Production of iron
• Production of titanium

The dominant ore for aluminium is gibbsite Al2O3.3H2O
The dominant ores for lithium and magnesium are chlorides
The dominant ores for iron and titanium are oxides.

mollwollfumble said:

We say that desalination is energy intensive.

I can’t help wondering how the energy required for other energy intensive processes compare with each other. For starters, how does the energy requirements for each of these energy intensive processes compare?

• Desalination of seawater
• Production of table salt by evaporation of seawater
• Production of liquid oxygen and nitrogen
• Electrolysis of water to get hydrogen
• Production of aluminium
• Production of lithium
• Production of magnesium
• Production of iron
• Production of titanium

The dominant ore for aluminium is gibbsite Al2O3.3H2O
The dominant ores for lithium and magnesium are chlorides
The dominant ores for iron and titanium are oxides.

Add one more energy intensive process to that

• Photosynthesis

mollwollfumble said:

mollwollfumble said:

We say that desalination is energy intensive.

I can’t help wondering how the energy required for other energy intensive processes compare with each other. For starters, how does the energy requirements for each of these energy intensive processes compare?

• Desalination of seawater
• Production of table salt by evaporation of seawater
• Production of liquid oxygen and nitrogen
• Electrolysis of water to get hydrogen
• Production of aluminium
• Production of lithium
• Production of magnesium
• Production of iron
• Production of titanium

The dominant ore for aluminium is gibbsite Al2O3.3H2O
The dominant ores for lithium and magnesium are chlorides
The dominant ores for iron and titanium are oxides.

Add one more energy intensive process to that

• Photosynthesis
  

Anything that uses sunlight counts as zero.

party_pants said:

mollwollfumble said:

mollwollfumble said:

We say that desalination is energy intensive.

I can’t help wondering how the energy required for other energy intensive processes compare with each other. For starters, how does the energy requirements for each of these energy intensive processes compare?

• Desalination of seawater
• Production of table salt by evaporation of seawater
• Production of liquid oxygen and nitrogen
• Electrolysis of water to get hydrogen
• Production of aluminium
• Production of lithium
• Production of magnesium
• Production of iron
• Production of titanium

The dominant ore for aluminium is gibbsite Al2O3.3H2O
The dominant ores for lithium and magnesium are chlorides
The dominant ores for iron and titanium are oxides.

Add one more energy intensive process to that

• Photosynthesis
  

Anything that uses sunlight counts as zero.

You’re claiming that sunlight isn’t energy?

mollwollfumble said:

party_pants said:

mollwollfumble said:

Add one more energy intensive process to that

• Photosynthesis
  

Anything that uses sunlight counts as zero.

You’re claiming that sunlight isn’t energy?

I’d imagine the claim is that sunlight is available from the great fusion reactor in the sky, without any additional effort or expense.

The warming of the atmosphere also requires a bit of energy, as does the production of heavy elements in atars, and also the building of mountain ranges.

mollwollfumble said:

party_pants said:

mollwollfumble said:

Add one more energy intensive process to that

• Photosynthesis
  

Anything that uses sunlight counts as zero.

You’re claiming that sunlight isn’t energy?

No, of course not. But I can see no great value in your list unless you are adding the inputs of that humans have to devise and manage. Filling a pond full of salty water and letting it evaporate I would only count the energy required for pumping it, not the sun in do the evap work. Of course just about every energy source we utislise is derived from the sun somehow.

it’s really changing structure, in some way, so the answer to your question I doubt is straightforward

I need think about it more

mollwollfumble said:

We say that desalination is energy intensive.

I can’t help wondering how the energy required for other energy intensive processes compare with each other. For starters, how does the energy requirements for each of these energy intensive processes compare?

• Desalination of seawater
• Production of table salt by evaporation of seawater
• Production of liquid oxygen and nitrogen
• Electrolysis of water to get hydrogen
• Production of aluminium
• Production of lithium
• Production of magnesium
• Production of iron
• Production of titanium

The dominant ore for aluminium is gibbsite Al2O3.3H2O
The dominant ores for lithium and magnesium are chlorides
The dominant ores for iron and titanium are oxides.

Let’s start with Gibbs free energy of formation for the metals

Desalination at 36% efficiency (best so far) is 2 kWh/m3.
… which equates to 7.2 kJ per litre.
Evaporation of water is 44 kJ/mol. (we don’t need complete evaporation to get NaCl)
The Claude cycle for liquefaction of air is 25% efficient.
Cooling air at ambient temperature requires 29.13 J/mol/K, 1 J/g/K.
Cooling air at -160˚C requires 29.57 J/mol/K, not significantly different.
So cooling air 214 degrees requires 6.3 kJ/mol.
H2O add 237.2 kJ/mol to get hydrogen and oxygen.
Al2O3 add 1576.5 kJ/mol to get aluminium and oxygen. But that’s the wrong ore.
LiCl add 383.7 kJ/mol to get lithium and chlorine.
MgCl2 add 592.5 kJ/mol to get magnesium and chlorine.
CO2 is 394.6 kJ/mol, I’ll need that for steel.
Hematite is Fe2O3 with 741 kJ/mol, the most common ore.
TiCl4 is 737.2.
TiO2 is 889.1.
Photosynthesis energy is 1883 kJ/mol of O2 evolved.

certainly say with confidence that maintaining the entirety of life on earth, the organic structure, and systems if you like, is very energy intensive.

that’s a given

transition said:

certainly say with confidence that maintaining the entirety of life on earth, the organic structure, and systems if you like, is very energy intensive.

that’s a given

or is it?

transition said:

transition said:

certainly say with confidence that maintaining the entirety of life on earth, the organic structure, and systems if you like, is very energy intensive.

that’s a given

or is it?

You need about 1/2 kw per sq metre to maintain life on earth. That seems pretty intensive to me.

party_pants said:

mollwollfumble said:

Add one more energy intensive process to that

• Photosynthesis
  

Anything that uses sunlight counts as zero.

Thinking further, you do have a very good point. The conversion of sunlight into electricity is a low efficiency process, and that needs to be factored into the comparison.

mollwollfumble said:

mollwollfumble said:

We say that desalination is energy intensive.

I can’t help wondering how the energy required for other energy intensive processes compare with each other. For starters, how does the energy requirements for each of these energy intensive processes compare?

• Desalination of seawater
• Production of table salt by evaporation of seawater
• Production of liquid oxygen and nitrogen
• Electrolysis of water to get hydrogen
• Production of aluminium
• Production of lithium
• Production of magnesium
• Production of iron
• Production of titanium

The dominant ore for aluminium is gibbsite Al2O3.3H2O
The dominant ores for lithium and magnesium are chlorides
The dominant ores for iron and titanium are oxides.

Let’s start with Gibbs free energy of formation for the metals

Desalination at 36% efficiency (best so far) is 2 kWh/m3.
… which equates to 7.2 kJ per litre.
Evaporation of water is 44 kJ/mol. (we don’t need complete evaporation to get NaCl)
The Claude cycle for liquefaction of air is 25% efficient.
Cooling air at ambient temperature requires 29.13 J/mol/K, 1 J/g/K.
Cooling air at -160˚C requires 29.57 J/mol/K, not significantly different.
So cooling air 214 degrees requires 6.3 kJ/mol.
H2O add 237.2 kJ/mol to get hydrogen and oxygen.
Al2O3 add 1576.5 kJ/mol to get aluminium and oxygen. But that’s the wrong ore.
LiCl add 383.7 kJ/mol to get lithium and chlorine.
MgCl2 add 592.5 kJ/mol to get magnesium and chlorine.
CO2 is 394.6 kJ/mol, I’ll need that for steel.
Hematite is Fe2O3 with 741 kJ/mol, the most common ore.
TiCl4 is 737.2.
TiO2 is 889.1.
Photosynthesis energy is 1883 kJ/mol of O2 evolved.

To be continued.

Gibbsite 1155 kJ/mol, so don’t use 1576.5 for aluminium. Remember that this is Al2 so halve it for Al. And the situation is confused by other factors.

The Rev Dodgson said:

transition said:

transition said:

certainly say with confidence that maintaining the entirety of life on earth, the organic structure, and systems if you like, is very energy intensive.

that’s a given

or is it?

You need about 1/2 kw per sq metre to maintain life on earth. That seems pretty intensive to me.

I reckon, too

I was considering it as a conceptual reference