Stochastic state‐space temperature regulation of biochar production. Part I: Theoretical development

Abstract

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.

Efficacies of designer biochars in improving biomass and nutrient uptake of winter wheat grown in a hard setting subsoil layer

“…The blending, pelletilization and pyrolysis procedures that were followed in this study were reported in the early paper of Sigua et al (2014) and Novak et al (2014). Biochars were produced from each of the pelletized feedstocks using a slow pyrolysis procedure at 350°C (Cantrell and Martin, 2012). Each pelletized biochar particle had a length of between 10-20 mm and diameter of about 6-8 mm.…”

Effects of Biochar Blends on Microbial Community Composition in Two Coastal Plain Soils

“…Pine chip (PC; Pinus taeda) was collected in Berkeley County, SC, USA. The process for pyrolysis of PC and PL has been previously described [9,33]. Briefly, the PC and PL were hammer milled into 6 mm flakes, blended on a per weight basis, and then pelletized through a 6.4 mm die using a PP2000 pellet mill (Pellet Pros, Inc., Davenport, IA, USA).…”

“…PL alone and PC:PL blends required the addition of deionized water to achieve a 30% moisture content for pelletization, while PC alone required the addition of a 50:50 (w:w) addition of deionized water and soybean oil to achieve a 30% moisture content for proper pelletization. Pelletized feedstocks were then subjected to slow pyrolysis at 350 °C in a retort [33] with a residence time of 2 h. After pyrolysis, pellets were retained by sorting with a 2 mm sieve. For this particular study, a post-pyrolysis step was incorporated to grind all biochar pellets into a dust capable of passing through a 0.42 mm sieve.…”

Increasing biomass of winter wheat using sorghum biochars

“…Prior to a run, the sorghum was oven-dried (103°C) overnight and then loaded into a mesh basket and placed into a Lindberg electric box furnace equipped with a gas tight retort (Model 51662; Lindberg/MPH, Riverside, MI). This particular furnace-retort was specially modified with a stochastic state-space regulator (Cantrell and Martin 2012) to ensure precision regulation of the final charring temperature. Samples were pyrolyzed under the following temperature schedule: (1) 60 min at 200°C for equilibration, (2) 240 min at 500°C, and (3) cooldown 4.25°C min −1 to 100°C.…”