title: Stochastic state-space temperature regulation of biochar production. Part I: Theoretical development.
abstract: BACKGROUND
  The concept of a designer biochar that targets the improvement of a specific soil property imposes the need for production processes to generate biochars with both high consistency and quality. These important production parameters can be affected by variations in process temperature that must be taken into account when controlling the pyrolysis of agricultural residues such as manures and other feedstocks.
  
  
  RESULTS
  A novel stochastic state-space temperature regulator was developed to accurately match biochar batch production to a defined temperature input schedule. This was accomplished by describing the system's state-space with five temperature variables--four directly measured and one change in temperature. Relationships were derived between the observed state and the desired, controlled state. When testing the unit at two different temperatures, the actual pyrolytic temperature was within 3 °C of the control with no overshoot.
  
  
  CONCLUSIONS
  This state-space regulator simultaneously controlled the indirect heat source and sample temperature by employing difficult-to-measure variables such as temperature stability in the description of the pyrolysis system's state-space. These attributes make a state-space controller an optimum control scheme for the production of a predictable, repeatable designer biochar.
authors: USDA-ARS Coastal Plains Soil, Water & Plant Research Center, 2611 West Lucas Street, Florence, SC 29501-1241, USA. keri.cantrell@ars.usda.gov.
authors: Keri B
authors: KB
authors: Cantrell
authors: Jerry H
authors: JH
authors: Martin
mesh_terms: D000465:Algorithms; D000821:Animal Feed / Q000032:analysis / Q000191:economics; D000822:Animal Husbandry / Q000191:economics; D002606:Charcoal / Q000032:analysis / Q000737:chemistry* / Q000191:economics; D055598:Chemical Phenomena; D003198:Computer Simulation; D005308:Fertilizers / Q000032:analysis* / Q000191:economics; D006361:Heating / Q000295:instrumentation; D006358:Hot Temperature; D007220:Industrial Waste / Q000032:analysis / Q000191:economics; D007700:Kinetics; D008372:Manure / Q000032:analysis; D008956:Models, Chemical; D009584:Nitrogen / Q000737:chemistry; D011786:Quality Control; D015203:Reproducibility of Results; D012820:Silage / Q000032:analysis / Q000191:economics; D013269:Stochastic Processes; D014481:United States
chemical_list: D005308:Fertilizers; D007220:Industrial Waste; D008372:Manure; C540010:biochar; D002606:Charcoal; D009584:Nitrogen