{"id":11418,"date":"2024-05-31T10:35:21","date_gmt":"2024-05-31T08:35:21","guid":{"rendered":"https:\/\/blog.mr-int.ch\/?p=11418"},"modified":"2024-06-01T11:29:31","modified_gmt":"2024-06-01T09:29:31","slug":"hydrogen-takes-on-the-colour-of-co2","status":"publish","type":"post","link":"https:\/\/blog.mr-int.ch\/?p=11418&lang=en","title":{"rendered":"Hydrogen takes on the colour of CO2"},"content":{"rendered":"\n

Correction!<\/strong> 
\nAn attentive reader points out that the oxygen balance in the atmosphere would remain zero if the hydrogen produced were ultimately burnt, either directly or via synthetic fuels. The considerations in this article therefore only concern the most interesting uses of H2, those that produce stable materials, such as steel or other durable goods. This will therefore only be of relative importance. <\/span><\/p>\n\n\n\n

The philosophical metal of ecologism is hydrogen, the first element on the table, whose virtues are such that it should solve all the ills associated with the chase after fossil fuels. The two chemical equations in the title image depict a perfect world with a carbon-free energy supply. Except that the heretic on duty spots the blind spot of the \u00ab\u00a0climate credulous\u00a0\u00bb: stoichiometry.<\/p>\n\n\n\n

The water molecule would therefore have to be broken, for example by electrolysis or, one day, by thermolysis, to obtain hydrogen.<\/p>\n\n\n\n

Once enough electricity will have been produced in a more or less efficient but carbon-free way, even more will be lost in the electrolysis process to obtain hydrogen that will be burnt to power cars or turbines, with some heating added on the way. All it produces is water vapour, which nobody is afraid of.<\/p>\n\n\n\n

Or, more sophisticated but even less efficient, carbohydrates or ammonia will be synthesised to obtain liquid fuels useful for aviation or for chemicals. H2<\/sub> will also be used to reduce iron ore to produce coke-free steel. In this way, CO2<\/sub> is recycled in the most expensive way possible, but it sounds virtuous.<\/p>\n\n\n\n

\"combustion\"
Fuel synthesis<\/figcaption><\/figure>\n\n\n\n

Fascinated by these equations, and unaware that stoichiometry requires a full balance sheet, the world’s great leaders decided to ruin it so that a hydrogen sector could be developed. They believe it’s carbon-free! They are indeed capable of anything, and that is how they are recognised.<\/p>\n\n\n\n

Their little oversight is that, if a molecule of hydrogen is produced by the electrolysis or thermolysis of water, half a molecule of oxygen will also be formed, i.e. 8 g of O2<\/sub> for 2 g of H2<\/sub>.<\/p>\n\n\n\n

What happens to that oxygen? It will be diluted into the atmosphere because there is no point in capturing it. King of oxidisers, it will meet oxidisable substances, mainly biomass. And as with all combustion of organic matter, this will be coupled with the formation of… CO2<\/sub> !<\/mark><\/strong><\/p>\n\n\n\n

\"synfuels\"
Combustion of organic matter
Depending on the composition of the organic matter, combustion produces one molecule of CO2<\/sub> for each carbon atom it contains, and water is also formed.<\/em>
For one -CH2<\/sub>– group, one molecule of CO2<\/sub> is formed, using 1.5 of O2<\/sub>, or 44 g of CO2<\/sub> for 48 g of O2<\/sub>.<\/em>
For wood with a composition of CH1.44<\/sub>O0.66<\/sub>, it will be 44 g of CO2<\/sub> for 33 g ofO2<\/sub>.<\/em><\/figcaption><\/figure>\n\n\n\n

In a way that is still not fully understood, nature maintains a constant level of oxygen in the atmosphere with enormous annual inflows and outflows linked to photosynthesis and biomass decomposition or combustion. That O2<\/sub> will find its corresponding carbon-containing reducer.<\/p>\n\n\n\n

\n

For every 1 tonne of hydrogen produced for non-combustion uses<\/mark><\/strong>,
around 5.3 tonnes of CO2<\/sub> will be emitted.<\/p>\n<\/blockquote>\n\n\n\n

Anthropogenic!<\/strong>
With hydrogen, \u00ab\u00a0Zero Net\u00a0\u00bb is a long way off, because let’s not fool ourselves: thisCO2<\/sub> is definitely anthropogenic, caused by human action, because if there were no electrolysis, there would be no such emissions.<\/p>\n\n\n

\n
\"\"<\/figure>\n<\/div>\n\n\n

Voir aussi mon billet \u00ab\u00a0Les cancres ne feront pas passer l’hydrog\u00e8ne\u00a0\u00bb<\/a> du 23 novembre 2023.
Et ce billet en allemand sur le site de Carnot-Cournot-Netzwerk<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

Correction!  An attentive reader points out that the oxygen balance in the atmosphere would remain zero if the hydrogen produced were ultimately burnt, either directly or via synthetic fuels. The considerations in this article therefore only concern the most interesting uses of H2, those that produce stable materials, such as steel or other durable goods. … Continue reading \u00ab\u00a0Hydrogen takes on the colour of CO2\u00a0\u00bb<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":11396,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"iawp_total_views":15,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[1,37,35],"tags":[77,707,280,709,708],"class_list":["post-11418","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","category-climate","category-energy","tag-co2","tag-co2-en","tag-electrolysis","tag-electrolysis-en","tag-oxygen"],"_links":{"self":[{"href":"https:\/\/blog.mr-int.ch\/index.php?rest_route=\/wp\/v2\/posts\/11418","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.mr-int.ch\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.mr-int.ch\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.mr-int.ch\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.mr-int.ch\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=11418"}],"version-history":[{"count":0,"href":"https:\/\/blog.mr-int.ch\/index.php?rest_route=\/wp\/v2\/posts\/11418\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blog.mr-int.ch\/index.php?rest_route=\/wp\/v2\/media\/11396"}],"wp:attachment":[{"href":"https:\/\/blog.mr-int.ch\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=11418"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.mr-int.ch\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=11418"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.mr-int.ch\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=11418"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}