Techno-Economic Analysis Of Guayule (Parthenium Argentatum) Pyrolysis Biorefining: Production Of Biofuels From Guayule Bagasse Via Tail-Gas Reactive Pyrolysis

The tire industry is currently considering natural rubber from guayule (Parthenium argentatum Gray) as a viable alternative to imported Hevea natural rubber, or petroleum-based synthetics, to meet expanding materials needs of the industry. However, only 5–10% of the harvested guayule plant is converted into rubber latex. For economic sustainability, the industry must identify viable uses for the balance residual, termed bagasse. Bioenergy production has been considered, but conversion facilities must be co-located to avoid additional costs in transportation of the bagasse. This study investigated the economics of processing a minimum of 200 metric ton per day (MTPD) of guayule bagasse to produce biofuels in a biorefinery co-located with a guayule latex processing facility. A unique aspect of the simulated process was the use of the tail gas reactive pyrolysis (TGRP) technology that formulates an intermediate bio-oil with less oxygenates and therefore requires only mild upgrading to fuel products. This achieved a yield of 16.2%, distributed in the gasoline (9.7%), jet fuel (5.6%), and diesel (0.9%) carbon ranges. The capital cost was estimated at $58.74 million (MM), and the annual operating cost was estimated at$14.19 MM. A discounted cash flow rate of return (DCFROR) analysis was conducted to evaluate the economic feasibility based on a 30-year plant life and 10% internal rate of return. The minimum fuel selling price (MFSP) calculated was 1.88 $/L for gasoline, 1.84$/L for jet fuel and 1.91 $/L for diesel fuel, clearly showing the limitations imposed by economies of scale of the current guayule bagasse availability. However, there is a potential to reduce the MFSP by increasing the facility capacity and utilizing the valuable co-products that accompany guayule pyrolysis biorefining. Sensitivity analysis indicates the MFSP of gasoline can be lowered to 0.96$/L considering the most optimistic scenario, comprising an integrated large facility of 2000 MTPD, lower cost of hydrogen, and the sale of a premium-quality residual guayule biorefinery coke

A Process Simulation Of Guayule Biorefining, Including An Exergy Analysis

The guayule (Parthenium argentatum) plant is a source of natural rubber and a possible high-energy biofuel. Herein guayule bagasse, the residual biomass after latex extraction, which accounts for 90% of the processed plant material, is modeled in a fast pyrolysis biorefining process. The simulation uses PRO/II® software and is based on data and processes used successfully in a bench scale facility. The unique 200-ton per day plant includes fast pyrolysis utilizing the tail gas reactive process followed by atmospheric separation, hydrodeoxygenation and final product separation, resulting in products similar to traditional fuels, i.e., gasoline, jet fuel and diesel. Approximately 10% of the biomass is converted to liquid fuels with 10% of this converted to gasoline, 34% jet fuel and 56 % diesel. These yields are compared to alternative feedstock and methods. The simulation results are utilized in an exergetic assessment. The depletion of exergy from its natural state (cumulative exergy demand, CExD) is considered as a measure of sustainability of the refining process. Breeding factors, measures of exergy production (the ratio of chemical exergy of the output products to the process exergy inputs), are determined. Results show, for the entire biorefining process, favorable breeding factors can possibly exceed 10, thus suggesting a favorable method of exergy production

Immobilized Streptavidin gradients as bioconjugation platforms

Surface density gradients of streptavidin (SAV) were created on solid surfaces and demonstrated functionality as a bioconjugation platform. The surface density of immobilized streptavidin steadily increased in one dimension from 0 to 235 ng cm(-2) over a distance of 10 mm. The density of coupled protein was controlled by its immobilization onto a polymer surface bearing a gradient of aldehyde group density, onto which SAV was covalently linked using spontaneous imine bond formation between surface aldehyde functional groups and primary amine groups on the protein. As a control, human serum albumin was immobilized in the same manner. The gradient density of aldehyde groups was created using a method of simultaneous plasma copolymerization of ethanol and propionaldehyde. Control over the surface density of aldehyde groups was achieved by manipulating the flow rates of these vapors while moving a mask across substrates during plasma discharge. Immobilized SAV was able to bind biotinylated probes, indicating that the protein retained its functionality after being immobilized. This plasma polymerization technique conveniently allows virtually any substrate to be equipped with tunable protein gradients and provides a widely applicable method for bioconjugation to study effects arising from controllable surface densities of proteins.Bryan R. Coad, Krasimir Vasilev, Kerrilyn R. Diener, John D. Hayball, Robert D. Short and Hans J. Griesse