Sewage Sludge Pyrolysis in Fluidized Bed, 1: Influence of Operational Conditions on the Product Distribution

Abstract

In this work, pyrolysis of sewage sludge in a fluidized bed was studied experimentally in order to obtain a liquid product able to be used in energetic applications. The influence of operational conditions on the product distribution was studied. The operational variables were as follows: temperature (450−650 °C), nitrogen flow rate (3.5−5.5 L(NTP) min−1), and solid feed rate (3.0−6.0 g min−1). Their influence was considered on the yields to the three pyrolysis products: solid, liquid, and gas. The liquid yield was mainly influenced by the bed temperature but also by the nitrogen flow rate and the solid feed rate. The bed temperature and the nitrogen flow rate showed a quadratic effect, and the maximum liquid yield was achieved at around 540 °C and around 4.5 L(NTP) min−1 of nitrogen. The solid feed rate just affected on the liquid yield at the lower temperatures studied, and the maximum liquid yield was obtained at the lowest solid feed rates. The design of experiments (DOE) statistical tool was used in the preparation of the work.

Catalytic post-treatment of the vapors from sewage sludge pyrolysis by means of γ-Al2O3: Effect on the liquid product properties

“…The reactor is heated by means of an electrical furnace [42]. The postcatalytic treatment was performed using a tubular Fixed Bed Reactor (FixBR).…”

“…The pyrolysis experiments were carried out during 2 h. Other operational conditions used in these experiments were a feeding rate of 6 g min − 1 of sewage sludge (solid feeding rate per volumetric unit 0.339 kg s −1 m −3 ) and a nitrogen flow of 4.4 dm 3 min −1 (measured at 298 K and 101 kPa; inlet nitrogen rate 0.074 m s −1 ), which were chosen according to previous studies [42,43].…”

Study of the pyrolysis liquids obtained from different sewage sludge

“…In wastewater treatment plants of high capacity, one of the most commonly used sewage sludge stabilization treatments is the anaerobic digestion. Pyrolysis of anaerobically digested sewage sludge in fluidized bed has been studied by several authors [10][11][12][15][16]. These authors have focused their attention on the maximization of the yield to the liquid product.…”

Furfurals As Chemical Platform For Biofuels Production

“…Figure 1 shows the simulation results of sewage sludge carbonization based on the properties of dewatered sewage sludge after anaerobic digestion from a local sewage treatment plant and experimental results of carbonization yield [23,24] (Table 1). Mass and energy balance calculations show a 0.08 (daf) product yield (y M ), 3.19 MJ/kg total energy required of units, 0.14 MJ/kg available energy from volatile gas (E A,CG ), and 0.5 MJ/kg available energy from carbonized liquid (E A,CL ).…”

“…The influence of the assumed efficiency of each unit on the LCA results can be estimated accordingly. Notes: * Source: [2]; ** Source: [23,24], recalculated by this study at 450 °C.…”