Materials Handling & Solids Characterization

Achieving the best process economics

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Optimizing and Scaling

The wide range of biomass—whether it is a single feedstock or mixed feedstock—introduces complexities in treating and handling the starting material and resultant products in a process scenario. What works at bench scale may not produce the same results at demonstration and pilot scales.

At ABPDU, our ultimate goal is to optimize processes to avoid problems during scale-up. During downstream polymerization processes, we focus on the specific structures and properties for potential end-user applications. This approach not only helps with quality control, but also allows us to develop the most economical processes.

Understanding Biomass Flow Properties: Changes in Viscosity versus Rheology
The reduced presence of water exponentially increases viscosity of biomass, which poses a number of mass transfer challenges, especially reducing efficacy of enzymes. You can see the drastic change in rheology due to reduced water availability on Avicel®, a form of microcrystalline cellulose.

High Solids Loading

A key feature of biomass is that it is a solid, unlike crude oil. Solids handling is one of the key risk drivers for scale up. Higher solids loading could lead to higher productivity in downstream fermentation processes. At high solids, however, biomass is typically fibrous and hygroscopic and requires special mixing and handling techniques at large-scale.

Performing chemistry on solids is more challenging from a cost and feasibility perspective. At ABPDU, we believe it is critical to obtain a fundamental understanding of the biomass flow properties under various unit operations to evaluate the requirements of mixing and handling techniques for high solid loadings.

Robust Process Design

Rheology of biomass can significantly influence the progress of chemical and biological conversion of biomass to monomeric sugars.

At ABPDU, we utilize extensive rheology to design processes that scale well. The information we obtain helps us balance process economics and quality.

    • Is a fed batch process better than a batch process?
    • How small a particle size is optimum?
    • Can you reduce capital expenditure by using a smaller reactor?
    • What type of pump can we use and what would be its specification?

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Materials Characterization & Solids Handling Options

Measuring Viscosity
Increasing the concentration of the biomass solids during biochemical conversion has a large potential in reducing production costs. These concentrated biomass slurries have highly viscous, non-Newtonian behavior that poses several technical challenges to the conversion process.
Understanding Solids to Liquids Behavior
The reduced presence of water exponentially increases viscosity of biomass, which poses a number of mass transfer challenges, especially affecting the capability of the catalyst. In a high solids slurry, the lack of water requires cellulase enzymes to perform effectively inspite of low water. As biomass is hydrolyzed, absorbed water is released into the newly forming aqueous phase and a drop in viscosity follows. Understanding changes in rheology of high solid slurries can provide several useful insights to improve production of sugars.
Optimizing Enzyme Activity at High Solids Loading
Enzymatic hydrolysis at high solids loadings is key to the scale-up of biochemical conversion processes, because of potentially higher sugar and ethanol titers and low hydraulic loads. However, high solids loading can result in lower conversion of glucan and xylan into fermentable sugars. We use extensive rheology and data analysis to design a highly productive saccharification process.

Related Papers, Articles, and Presentations

Scale-Up and Process Integration of Municipal Solid Waste Conversion Process

This paper presents two case studies on the scale-up and process integration of municipal solid waste conversion technology. In a partnership with Idaho National Labs, we successfully demonstrated 200-fold scale up of MSW blends IL acidolysis. We also developed an integrated process for ionic liquid based deconstruction technologies for MSW blends conversion. The scale up attempt will leverage the opportunity towards a cost-effective MSW blends conversion technology.

Under a DOE Work-For-Others agreement with FATER, ABPDU has been developing and validating an integrated waste-to-energy process. Key outcomes indicate that post-consumer absorbent hygiene products (AHPs) can be readily and economically converted — without using harsh or expensive pretreatment routes — to sugars and fuel intermediates.

Predictive Modeling and Rheological Estimation of Mixed Biomass Feedstocks

In a collaborative effort with INL, SNL, and JBEI, predictive modeling was used to evaluate and optimize traditional pretreatment methods for biomass mixture compositions to maximize sugar yield and minimize furfural production. The collaboration encompassed compositional analysis of feedstocks, solids loading during pretreatment for mixed feedstock, enzymatic hydrolysis on unwashed solids, and sugar and furfural analysis. Predictive modeling could effectively identify the pretreatment catalyst and treatment conditions for an “optimal” biomass mixture and the optimal biomass mixture for a particular pretreatment system.


Process Scale-up of Municipal Solid Waste and Corn Stover Blends Conversion into Sugars


A collaboration between ABPDU, INL, and SNL as to whether blends of municipal solid waste (MSW) and corn stover (CS) could meet cost and quality targets yielded valuable results. The team successfully developed an integrated process for ionic liquid (IL) based deconstruction technologies. They also demonstrated a 200-fold scale up MSW/CS blends IL acidolysis. The scale up attempt and process integration will leverage the opportunity towards a cost-effective sugar/lignin production technology.


FATER ABPDU Waste-to-Bioenergy Process Partnership


ABPDU has been developing and validating an integrated waste-to-energy process under a DOE work-for-others (WFO) agreement with FATER, an Italian JV between Procter & Gamble and the Angelini Industrial Group.

Key outcomes indicate that post-consumer absorbent hygiene products (AHP) can be readily and economically converted — without using harsh or expensive pretreatment routes — to fermentable sugar intermediates as well as biofuel and bio-based chemical products.

Rheology of 1-Ethyl-3-Methylimidazolium Acetate and Lignocellulosic Biomass Mixtures

Rheology is the science of deformation and flow of matter, investigating the response of materials to applied stress or strain Rheological properties describe flow characteristics and textural behavior of substances.