S. Murat Sen

Production of renewable jet fuel range alkanes and commodity chemicals from integrated catalytic processing of biomass

This article presents results from experimental studies and techno-economic analysis of a catalytic process for the conversion of whole biomass into drop-in aviation fuels with maximal carbon yields. The combined research areas highlighted include biomass pretreatment, carbohydrate hydrolysis and dehydration, and catalytic upgrading of platform chemicals. The technology centers on first producing furfural and levulinic acid from five- and six-carbon sugars present in hardwoods and subsequently upgrading these two platforms into a mixture of branched, linear, and cyclic alkanes of molecular weight ranges appropriate for use in the aviation sector. Maximum selectivities observed in laboratory studies suggest that, with efficient interstage separations and product recovery, hemicellulose sugars can be incorporated into aviation fuels at roughly 80% carbon yield, while carbon yields to aviation fuels from cellulose-based sugars are on the order of 50%. The use of lignocellulose-derived feedstocks rather than commercially sourced model compounds in process integration provided important insights into the effects of impurity carryover and additionally highlights the need for stable catalytic materials for aqueous phase processing, efficient interstage separations, and intensified processing strategies. In its current state, the proposed technology is expected to deliver jet fuel-range liquid hydrocarbons for a minimum selling price of

A strategy for the simultaneous catalytic conversion of hemicellulose and cellulose from lignocellulosic biomass to liquid transportation fuels

4.75 per gallon assuming nth commercial plant that produces 38 million gallons liquid fuels per year with a net present value of the 20 year biorefinery set to zero. Future improvements in this technology, including replacing precious metal catalysts by base metal catalysts and improving the recyclability of water streams, can reduce this cost to

Production of butene oligomers as transportation fuels using butene for esterification of levulinic acid from lignocellulosic biomass: process synthesis and technoeconomic evaluation

2.88 per gallon.

Process systems engineering studies for the synthesis of catalytic biomass-to-fuels strategies

We develop and evaluate an integrated catalytic conversion strategy, which utilizes both the hemicellulose and cellulose fractions of lignocellulosic biomass to produce liquid hydrocarbon fuels (butene oligomers). In this strategy, the cellulose and hemicellulose fractions are simultaneously converted to levulinic acid (LA), using LA-derived γ-valerolactone (GVL) as a solvent. The LA is then converted to GVL, which is subsequently converted to butene, and then to butene oligomers. To generate the integrated strategy, we develop separation subsystems to achieve experimentally optimized feed concentrations for the catalytic conversion steps. Importantly, to minimize the utility requirements of the overall process, we perform heat integration, which allows us to satisfy all heating requirements from combustion of biomass residues, which are also used to produce steam for electricity generation. In addition, we develop an alternative design in which there is no electricity generation, study alternative feedstocks, and perform sensitivity analyses. Our technoeconomic analysis shows that the integrated strategy using hybrid poplar feedstock leads to a minimum selling price of

A superstructure-based framework for simultaneous process synthesis, heat integration, and utility plant design

4.01 per gallon of gasoline equivalent for butene oligomers if biomass residues are sold as low quality fuel.

A Superstructure-Based Framework for Simultaneous Process Synthesis, Heat Integration, and Utility Plant Design

Levulinic acid (LA) is a valuable platform chemical upon which biorefining strategies for the production of chemicals, fuels and power can be established. Herein, we report the results of process synthesis and technoeconomic analysis studies for the conversion of lignocellulose derived LA to liquid fuels through the intermediate formation of levulinate esters. In this strategy, esterification of levulinic and formic acids with alkenes (i.e., butene) produces hydrophobic esters, which extract the unconverted LA from the aqueous sulfuric acid solution. Following the γ-valerolactone (GVL) production from LA and levulinate esters, GVL is converted to butene, hence providing the butene required for esterification and butene oligomers. The minimum selling price of butene oligomers from a 1365 dry tons per day of loblolly pine processing facility is calculated to be

Synthesis of catalytic biomass-to-fuels strategies

4.92 per gallon of gasoline equivalent. Our analysis shows that the biomass feedstock price is the main cost driver.

Catalytic conversion of lignocellulosic biomass to fuels: Process development and technoeconomic evaluation

The goal of this paper is to show how chemical process synthesis and analysis studies can be coupled with experimental heterogeneous catalysis studies to identify promising research directions for the development of strategies for the production of renewable fuels. We study five catalytic biomass-to-fuels strategies that rely on production of platform chemicals, such as levulinic acid and fermentable sugars. We first integrate catalytic conversion subsystems with separation subsystems to generate complete conversion strategies, and we then develop the corresponding process simulation models based on experimental results. Our analyses suggest that catalytic biomass-to-fuel conversion strategies could become economically competitive alternatives to current biofuel production approaches as a result of iterative experimental and computational efforts.

An optimization-based assessment framework for biomass-to-fuel conversion strategies

Abstract We propose a superstructure optimization framework for process synthesis with simultaneous heat integration and utility plant design. Processing units in the chemical plant can be modeled using rigorous unit models or surrogate models generated from experimental results or off-line calculations. The utility plant subsystem includes multiple steam types with variable temperature and pressure. For the heat integration subsystem, we consider variable heat loads of process streams as well as variable intervals for the utilities. To enhance the solution of the resulting mixed-integer nonlinear programming models, we develop (1) new methods for the calculation of steam properties, (2) algorithms for variable bound calculation, and (3) systematic methods for the generation of redundant constraints. The applicability of our framework is illustrated through a biofuel case study which includes a novel non-enzymatic hydrolysis technology and new separation technologies, both of which are modeled based on experimental results.

Conversion of biomass to sugars via ionic liquid hydrolysis: process synthesis and economic evaluation.

We propose a new framework for simultaneous chemical process synthesis, heat recovery network design, and utility plant design. We generate compact surrogate unit models to describe processes based on new technologies. We also consider (1) process streams with variable heat loads and temperatures, and (2) multiple steam types of variable temperature. We illustrate the applicability of our framework using a novel process for the non-enzymatic production of sugars from lignocellulosic biomass.