thank you for your reply Dgs.
The most important detail that differs the catalyst proposed by me from the traditional one (NaOH / KOH) is the possibility of it's recovery by phase separation in the first stage of the process(catalyst is carried by propylene glycol ),in the second step the another form of catalyst is used (impregnated zeolites grains), so it's always settled on the bottom of reactor(or maintained in a fixed bed ,if the contiunous flow reactor is used(not tested practically yet,but it will be next target of my trials).
The two stages described are transesterification processes (bases) and probably the third stage (especially for the used fat) will be necessary to obtain the acceptable conversion efficiency (acidic esterification of FFA, again using zeolites this time with acidic properties). I am currently working on the selection of proper components for this stage.
For people who produce biodiesel by classical methods (especially when pre-treated with sulfuric acid to reduce the acid number of used oil) it may sound strange that I suggest a reversed method, but the chemical components of the proposed catalyst do not cause a high level of saponification (the process is not stopped because of the formation of soap and hydrolysis of glycerides).
Perhaps it is possible to combine last both (basic/acidic on zeolites ) stages in one process (I have to do more tests, my previous observations confirm the theoretical possibility of this simplification).
The ethanol-to-oil ratio used in my tests is 300 ml E85(255 ml of pure ethanol) per 1000 ml oil / fat. In this proportion, it is necessary make a second step by use a catalyst on zeolites to achieve the minimum conversion to maintain a liquid form by biodiesel made of, for example, chicken fat.
The high conversion factor is available above the volume ratio ethanol / fat 1: 1 only with the first step described (catalyst in propylene glycol solution).But such proportions are used in industry, I know that amateurs are interested in a method that does not require the distillation of excess alcohol to maintain profitability.
The functionality of the catalyst impregnated with zeolites is probably based on the phenomenon of local shift of chemical equilibrium towards products (thats why the effect occurs in low excess of alcohol).
Zeolites have properties similar to molecular sieves, I noticed that zeolites properly impregnated with a catalyst are able to selectively continue the transeterification on their own surface, absorbing di and monoglycerides remaining after the first part of the process (which is necessary for the partial "cracking" of triglycerides with low excess of alcohol). This phenomenon is probably related by a large difference in viscosity between esters and mono / di glycerides.
At this stage, I have not calculated the exact cost of the catalyst required to produce 1 liter of biodiesel, the estimated one-time cost of the catalyst should not exceed 1 euro per liter of ester (it seems expensive,but probably the catalyst may be used more than ten times, it requires more practical tests).
The benefits of using a cheaper alcohol source such as e85 compared to methanol should make this method competitively priced. Another important factor for profitability will be the possibility of processing low quality waste fats that are unsuitable for use in the classic process (high FFA's levels).
At the moment there are many problems that I have not solved practically (for example, safe removal of hydrocarbons from e85 remaining in biodiesel after the process) and many others. However, potential buyers may be interested in attempting to use a catalyst in the production of methyl esters before the ethanol process will be refined(perhaps for even slightly hydrated).
In the coming weeks I will share new information in this thread. I have some results of ethyl ester analysis done in professional laboratories. I will also put in some photos and schemes.My personal life slows down all sort of testing, so please be patient with all delays that may occur because of this.
I think, however, that by the end of this year it will be possible to send free samples of catalysts from me privately (only with the shipping fee on the client's side).
Also, if someone would like to obtain information about the pyrolysis of fats, I refer to my older thread in the forum ("Catalytic pyrolysis of WVO, unusual method, mild conditions").
