Environment & Energy
Showing Original Post only (View all)Continuous Hydrolysis of CuCl2 in the Copper Based Thermochemical Hydrogen Cycle [View all]
The paper to which I will very briefly refer is this one: Continuous CuCl2 Hydrolysis in the Six-Step Cu–Cl Thermochemical Cycle for Green Hydrogen Production Ramdas S. Kadam, Ashwini B. Nirukhe, and Ganapati D. Yadav Industrial & Engineering Chemistry Research 2024 63 (48), 20787-20799.
I have low tolerance for all the bullshit handed out about "green" hydrogen, because usually "green" - a much abused word these days - is connected with so called "renewable energy," a mass and land intensive scheme popularly described as "green," although it is no such thing. The vast sums of money squandered on so called "renewable energy" has been useless, since so called "renewable energy" depends on access to fossil fuels, and thus has had no effect on arresting or slowing the extreme global heating we now observe. In fact things are getting worse faster.
I especially hold in contempt the tiresome, unworkable and frankly dangerous old idea of treating hydrogen as a consumer fuel; this said it is a valuable captive chemical intermediate when handled by highly trained chemical engineers in industrial plants.
There are thousands upon thousands of papers on thermochemical hydrogen production in the literature, across a vast array of hydrogen cycles. The most popular of these is the sulfur iodine cycle, and modifications thereof, which I personally prefer given it uses only liquid and gas phase molecules, and thus, at least in theory is capable of continuous operation in a closed system. The paper here refers another well known cycle the CuCl2 cycle, which also features many permutations (including the change of the halides from chlorine to bromine or iodine). The particular cycle discussed here uses electrolysis to generate chlorine, something I generally do not applaud, although with appropriate heat networks to employ process intensification, it may be possible to continuously produce excess electricity for which no immediate use is available other than electrolysis.
In modern times, perhaps to get grants, thermochemical cycles are often proposed using solar thermal garbage to provide the heat for reactions, since obeisance to the worship of so called "renewable energy" has become an element of quasi-religious faith that is regrettably widely spread throughout the world, despite the fact that it does nothing useful generating far more complacency than energy, complacency that has left the world in flames.
What is notable about this paper is how it defines "green," which is largely consistent with how I define it.
To wit, from the introduction of the paper:
Hydrogen as a clean energy source has the potential to be a viable replacement for traditional fossil fuels. Hydrogen usage on a large scale will require sustainable, low-cost, and environmentally friendly methods of production. (1,2) If hydrogen is produced using renewable energy sources, it can reduce greenhouse gas emissions (GHG) that contribute to climate change. Cu–Cl cycles represent promising water-splitting techniques that can be integrated, for instance, with nuclear reactors among other green energy sources. These cycles employ thermal processes to decompose water into oxygen and hydrogen, utilizing a series of intermediate reactions. Importantly, these cycles ensure the recycling of all other intermediate chemicals and result in zero emissions being released into the environment. The Cu–Cl cycle is an attractive alternative for hydrogen production by thermochemical water breakdown because it requires lower temperatures and has greater overall efficiency than other thermochemical cycles. (3,4)...
There are several dubious locutions in the introduction, and one should note the genuflection in the direction of "other green energy sources" of which there are effectively none.
Table 1 gives the reaction series for the CuCl2 cycle and the temperatures at which the reactions take place:

A few graphics from the text beginning with a flow diagram:

The caption:
A point relevant to the control of particle size:

The caption:
A schematic for a reactor for continuous flow of the CuCl2 hydrolysis reaction.

The caption:
Again, I'm not really a CuCl2 thermochemical cycle kind of guy, but what I appreciate is that the article delineates, in the way I do, what "green" might really be.
Have a nice weekend.
