Technological prospecting in the production of charcoal: A patent study

Charcoal is an important source of renewable energy with great industrial importance as a bio-thermo-reducer in the production of pig iron and steel. To increase the quality and yield of charcoal, it is necessary to invest in the continuous improvement of carbonization kilns and in the control of the carbonization process. However, studies to characterize the technologies currently used in the production of charcoal are lacking. This paper aims to fill this research gap by searching for patent documents of kilns used worldwide in the production of charcoal. A total of 172 carbonization kiln patents have been found and most of them contain technological improvements. The following were emphasized: information on the structure of the kiln, means of mechanizing the loading and unloading of kiln, the reuse of gases and vapors from the carbonization process, control of the carbonization process, rapid cooling of the produced charcoal while it is still inside the kiln, and possible advantages of adopting such technologies. However, despite these technological advances, most of the world's charcoal production still comes from low-technology, traditional kilns, resulting in lower yield and variable charcoal quality. Also discussed are the reasons for the lack of consolidation in the production environment of technologies proposed by kiln patents, considering the fact that they could increase the yield and quality of charcoal and, consequently, reduce the demand for wood.