Are solid fuels with calorific values >= 10,000 kcal/kg (42 MJ/kg) physically possible?

I have seen laboratory documentation from a reputable lab in southeast Asia that a company has achieved a solid fuel product made from landfill material with a high heating calorific value ($CV$) of approximately 10,000 kcal/kg (42 MJ/kg). The technology is referred to as Refuse Derived Fuel (RDF). From what I understand, such calorific values are only even possible with fluid fuels such as liquefied natural gas (etc.) which can get up to 12,000 kcal/kg.


Doing some calculations around the fixed carbon composition of landfill as similar to a question [I've asked previously](https://chemistry.stackexchange.com/questions/168959/how-can-combusted-methane-from-landfill-samples-be-quantified), I found that the fixed carbon ($FC$) content of the feedstock composition must equal approximately 130% to have the CV mentioned above. This number is obviously impossible but I'm very surprised that it was reported by this lab. Similar products usually get a CV of around 2500 - 5000 kcal/kg if they're lucky. There are several formulas to calculate CVs, the one I've used is below and notably only a function of the fixed carbon content to calculate the calorific value [kcal/kg], so perhaps my equation is too simplified?


$$CV = 0.196FC + 14.119$$


The company of course masks the idea saying it's their intellectual property (etc.) but I'm just curious of if this is even possible or should the laboratory's reputation be called into question?




**It is clearly possible for *fuels* to have higher calorific values per kg, even solid ones**


Calorific values of fuels are well known and available from many sources. For example, [this source](https://www.forestresearch.gov.uk/tools-and-resources/fthr/biomass-energy-resources/reference-biomass/facts-figures/typical-calorific-values-of-fuels/) list the values of fuel oil as 42.5 MJ/kg (same value if you prefer GJ/tonne) and LPG as 46.3 MJ/kg so there doesn't appear to be a simple obvious limit for fuels. Obviously fuel oil is a liquid and LPG a mildly compressed gas under normal conditions.


But one of the reasons for their higher calorific values is that compounds with larger proportions of hydrogen tend to have higher values than ones with more carbon (which when mostly pure has about 33 MJ/kg).


So solid hydrocarbon compounds should be better. And they are with paraffin wax [coming in at about](https://en.wikipedia.org/wiki/Paraffin_wax) the 42 MJ/kg level.


So there is no good reason to expect even slightly higher values to be impossible. we already have examples fuels with that calorific capacity.


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