Ammonia Fiber Explosion Research Articles

Effect of Ammonia Fiber Expansion Combined with NaOH Pretreatment on the Resource Efficiency of Herbaceous and Woody Lignocellulosic Biomass.

The most essential issue facing the world today is the provision of energy and sustainable consumption of natural resources. Pretreatment is an essential step to produce biofuels from lignocellulosic biomass. In this study, ammonia fiber explosion (AFEX) combined with NaOH (A-NaOH) pretreatment effects on the characteristics of Pennisetum sinese (herbaceous), oak (hardwood), and camphor wood (softwood) were assessed using enzymatic efficiency analysis, thereby identifying the composition properties of subsequent bio-H2 production. The results show that the lignin removal (84.2%, 59.7%, and 36.7%, respectively) at 5%A-NaOH conditions and enzymatic efficiency (36.2%, 9.7%, and 6.5%, respectively) of Pennisetum sinese (P. sinese), oak, and camphor wood were significantly increased under 4% A-NaOH conditions. Further A-NaOH pretreatment significantly promoted dark fermentation bio-H2 production (152.3, 99.1, and 76.9 mL/g TS, respectively) and volatile acid production (4660.2, 3720.2, and 3496.2 mg/L, respectively) of P. sinese, oak, and camphor wood. These findings show that A-NaOH pretreatment is an effective means of utilization of lignocellulose resources.

Valorization of lignin components into gallate by integrated biological hydroxylation, O-demethylation, and aryl side-chain oxidation.

Converting lignin components into a single product is a promising way to upgrade lignin. Here, an efficient biocatalyst was developed to selectively produce gallate from lignin components by integrating three main reactions: hydroxylation, O-demethylation, and aryl side-chain oxidation. A rationally designed hydroxylase system was first introduced into a gallate biodegradation pathway–blocked Rhodococcus opacus mutant so that gallate accumulated from protocatechuate and compounds in its upper pathways. Native and heterologous O-demethylation systems were then used, leading to multiple lignin-derived methoxy aromatics being converted to gallate. Furthermore, an aryl side-chain oxidase was engaged to broaden the substrate spectrum. Consequently, the developed biocatalyst showed that gallate yields as high as 0.407 and 0.630 g of gallate per gram of lignin when alkaline-pretreated lignin and base-depolymerized ammonia fiber explosion lignin were applied as substrates, respectively. These results suggested that this rationally developed biocatalyst enabled the lignin valorization process to be simple and efficient.

Chemical Pretreatment of Lignocellulosic Biomass for the Production of Bioproducts: An Overview

Lignocellulosic biomass has attracted great interest from researchers. It was due to the abundance of this valuable material which can be converted into value-added materials such as nanocellulose, biocomposites, bioelectricity, biohydrogen and biosugars. Lignocellulosic biomass is consisting of the three major components which are cellulose, hemicellulose and lignin. In order to utilize lignocellulosic biomass for bioproducts manufacturing, they need to be pretreated prior to further processing. Pretreatment can be carried out either by mechanical, chemical, biological or combination of all these methods. Chemical pretreatment are the common method used to pretreat the lignocellulosic biomass in order to completely or partially remove the components. During the past few years, a large number of chemical pretreatment including lime, acid, steam explosion, sulfur dioxide explosion, ammonia fiber explosion, ionic liquid and others have been discovered for efficient pretreatment of biomass. Several types of chemical pretreatment of fibers and their future direction and also challenges were tackled in this review. This review could be beneficial for future directions in the pretreatment of fiber for the development of several products.

Integrated Renewable Production of Sorbitol and Xylitol from Switchgrass.

This work deals with the design of integrated facilities for the production of xylitol and sorbitol from lignocellulosic biomass. Xylitol can be obtained from xylose via fermentation or catalytic hydrogenation. Sorbitol is obtained from glucose, but preferably from fructose, and also via fermentation or catalytic hydrogenation. Fructose can be obtained from glucose via isomerization. Thus, a superstructure of alternatives is formulated to process switchgrass, corn stover, miscanthus, and other agricultural and forestry residues. Different pretreatments, such as dilute acid or ammonia fiber explosion (AFEX), for the fractionation of the biomass are evaluated. Next, after hydrolysis, the C5 and C6 sugars are processed separately for which a catalytic or a fermentation stage are considered. Glucose has to be isomerized before it can be processed. Finally, crystallization in a multistage evaporator system is used for purification. The optimization of the system is done by the use of dilute acid and the catalytic system. A system of 3 crystallizers is selected. For a facility that produces 145 kt/yr of xylitol and 157.6 kt/yr of sorbitol, the investment adds up to 120.74 M€ for a production cost of 0.28 €/kg products. The inverse engineering of biomass was also performed resulting in a composition of 15% water, 20% cellulose, 40% hemicellulose, 15% lignin, and 5% ash. The closest biomass corresponds to Sargassum (brown algae), which is capable of producing 230.5 kt/yr of xylitol and 116 kt/yr of sorbitol with investment and production costs of 120.5 M€ and 0.25 €/kg products, respectively.

Life-cycle assessment-based comparison of different lignocellulosic ethanol production routes

This work conducts a life-cycle assessment (LCA) of ethanol production from sugarcane bagasse in the Indian context. A cradle-to-gate system boundary was considered, and a functional unit of 1 MJ of energy from ethanol was used. Eight pre-treatment technologies and four hydrolysis-fermentation technologies were considered, thereby comparing 32 process combinations. Process data were collected from various published studies, government reports and also personal communication, and were used to perform LCA. The ReCiPe and TRACI models were used to perform the impact assessment using OpenLCA 1.6.1. The results show that the dilute acid pre-treatment (DA) with simultaneous saccharification and fermentation (SSCF) processing route had lower impacts in most categories. The global warming potential for this combination was 0.132 kg CO2 eq. per MJ, with 85% of the contribution due to steam generation. The impact can be reduced to 0.019 kg CO2 eq. per MJ by using a natural gas for steam generation. Ammonia fiber explosion (AFEX) pre-treatment had the highest impact in many categories, primarily due to ammonia production, implying the importance of ammonia recycling. DA had a lower impact due to higher yields and lower biomass requirements. The water footprint ranged between 232 and 672 L/L of ethanol and was mostly dominated by agricultural water.

Pretreatment Ethanol From Cellulosic

<p><strong>Abstract.</strong> Pre-treatment is an important tool for practical cellulose conversion processes and can be carried out in different ways such as mechanical pre-treatment, steam explosion, ammonia fiber explosion, supercritical CO2 treatment, alkali or acid pretreatment, ozone pre-treatment, physicochemical pretreatment, dilute-acid pretreatment and biological pre-treatment. Biomass pretreatment with hot water (HW) is the most investigated physicochemical method use the differences in the thermal stabilities of the major components of lignocellulosic materials. Acid pretreatment of lignocellulosic biomass aims at increasing the sugar substrate digestibility, defined as the concentration of reducing sugars after the hydrolysis, by microorganisms. Acid hydrolysis is an attractive pretreatment method as the hemicellulose degradation runs with the efficiency of approximately 20-90%, depending on the process conditions. Dilute acid (DA) processes with continued research and development, no significant breakthroughs have been made to raise the glucose yields much higher than 65-70%. Acid pretreatment is much more effective than water and alkaline pretreatment in terms of cellulose accessibility increase compared with DA and HW pretreatment.</p><p> </p><p><strong>Keywords:</strong> ethanol, cellulosic, pre-treatment</p>

Integrated Renewable Production of ETBE from Switchgrass

In this work, we propose the optimization of a flowsheet for the conceptual design of an integrated renewable production of ETBE from ethanol and i-butene from switchgrass. A superstructure embedding a number of alternatives is proposed. Two technologies are considered for switchgrass pretreatment, dilute acid and a novel ammonia fiber explosion (AFEX), so that the structure of the grass is broken down. Only glucose is fermented to produce i-butene, while xylose is fermented to ethanol. Ethanol is purified using a multieffect column followed by molecular sieves and a PSA-membrane system is used to upgrade the i-butene. The problem is formulated as an MINLP, and solved for each pretreatment as an NLP. Finally, an economic evaluation is performed including a sensitivity analysis. Biomass composition determines the byproduct obtained. Dilute acid is the selected pretreatment due to the largest yield to sugars and the possibility of adjusting the production of both i-butene and ethanol for the needs to ETBE. ...

Economic value and environmental impact analysis of lignocellulosic ethanol production: assessment of different pretreatment processes

Second-generation bioethanol represents an interesting alternative to liquid fuels in times of increased concerns over global warming and energy security. However, the recalcitrant structure of lignocellulosic biomass feedstock makes necessary a pretreatment process to increase the conversion of sugars. Diluted acid, liquid hot water, steam explosion, ammonia fiber explosion, and organosolv pretreatments are assessed using a combined economic value and environmental impact analysis under a full biorefinery setup in order to assess the best pretreatment process from a techno-economic-environmental point of view. Five process areas were identified within each process considered: pretreatment stage, conversion stage, product purification and separation stage, water treatment stage, and cogeneration stage. A process simulation software was used to consider material and energy balances of the biorefineries with different pretreatment processes and to optimize the separation and purification processes (e.g., distillation columns). For the considered biomass and scenarios, all processes resulted in positive gains in terms of economic feasibility and carbon dioxide emissions. In particular, diluted acid can be considered the best pretreatment process to produce lignocellulosic bioethanol thanks to the best techno-economic-environmental performances, with the largest economic and environmental margins of 39.2 M$/year and 83.9 kt CO2/year, respectively.

Probabilistic Lifecycle Assessment of Butanol Production from Corn Stover Using Different Pretreatment Methods.

The recalcitrant nature of lignocelluloses requires a pretreatment process before the fermentative butanol production. The commonly used pretreatment processes, such as steam explosion, sulfuric acid, ammonia fiber explosion, ionic liquid (IL), and biological, require different quantities and types of process chemicals, and produce different quality and quantity of fermentable sugars. This study determines life-cycle greenhouse gas emissions (GHG) these pretreatment methods by developing a system-level process model including corn stover feedstock supply system and the downstream butanol production process. This study further evaluates the uncertainty associated with energy use and GHG emissions for each stage of the entire butanol production chain and provide the future optimization opportunities. Probabilistic results of these analyses describe a distribution of GHG emissions with an average of 18.09-1056.12 gCO2e/MJ and a 95% certainty to be less than 33.3-1888.3 gCO2e /MJ. The highest GHG emissions of IL-pretreatment of 1056.12 gCO2e/MJ reaches to 89.8 gCO2e/MJ by switching IL-recovery from 80 to 99 wt %, which is the most influential parameter for IL-pretreatment. Additionally, credits from excess electricity, butanol yield, nitrogen replacement, and diesel fuel for transportation and harvesting were the most influential parameters. Based on the current state of technologies, apart from ionic liquid and biological pretreatments, other pretreatment processes have similar metrics of sustainability.

Systematic procedure and framework for synthesis and evaluation of bioethanol production processes from lignocellulosic biomass

Bioethanol from lignocellulosic feedstock rises as a promising alternative to replace liquid fossil fuels in the energy market for the next years. However, the variety of available biomass combined with the necessity of possible pretreatments and their particular features make it difficult to clearly identify the favorable process routes. In this study a systematic approach consisting of seven steps was proposed to obtain possible and feasible alternatives for the conversion of lignocellulosic biomass into bioethanol. The method was exemplified with the aid of a general case study, from the biomass selection to possible by-products generation. The case study resulted in a corn stover based process to produce bioethanol through ammonia fiber explosion pretreatment. Following the systematic approach different alternatives were proposed to finally obtain the optimal flowsheet with a minimum ethanol selling price of 0.43$/kg of ethanol, 35.4% lower than the initial process.

Physico-Chemical Conversion of Lignocellulose: Inhibitor Effects and Detoxification Strategies: A Mini Review.

A pretreatment of lignocellulosic biomass to produce biofuels, polymers, and other chemicals plays a vital role in the biochemical conversion process toward disrupting the closely associated structures of the cellulose-hemicellulose-lignin molecules. Various pretreatment steps alter the chemical/physical structure of lignocellulosic materials by solubilizing hemicellulose and/or lignin, decreasing the particle sizes of substrate and the crystalline portions of cellulose, and increasing the surface area of biomass. These modifications enhance the hydrolysis of cellulose by increasing accessibilities of acids or enzymes onto the surface of cellulose. However, lignocellulose-derived byproducts, which can inhibit and/or deactivate enzyme and microbial biocatalysts, are formed, including furan derivatives, lignin-derived phenolics, and carboxylic acids. These generation of compounds during pretreatment with inhibitory effects can lead to negative effects on subsequent steps in sugar flat-form processes. A number of physico-chemical pretreatment methods such as steam explosion, ammonia fiber explosion (AFEX), and liquid hot water (LHW) have been suggested and developed for minimizing formation of inhibitory compounds and alleviating their effects on ethanol production processes. This work reviews the physico-chemical pretreatment methods used for various biomass sources, formation of lignocellulose-derived inhibitors, and their contributions to enzymatic hydrolysis and microbial activities. Furthermore, we provide an overview of the current strategies to alleviate inhibitory compounds present in the hydrolysates or slurries.

Comparative techno-economic analysis of steam explosion, dilute sulfuric acid, ammonia fiber explosion and biological pretreatments of corn stover

Pretreatment is required to destroy recalcitrant structure of lignocelluloses and then transform into fermentable sugars. This study assessed techno-economics of steam explosion, dilute sulfuric acid, ammonia fiber explosion and biological pretreatments, and identified bottlenecks and operational targets for process improvement. Techno-economic models of these pretreatment processes for a cellulosic biorefinery of 113.5 million liters butanol per year excluding fermentation and wastewater treatment sections were developed using a modelling software-SuperPro Designer. Experimental data of the selected pretreatment processes based on corn stover were gathered from recent publications, and used for this analysis. Estimated sugar production costs ($/kg) via steam explosion, dilute sulfuric acid, ammonia fiber explosion and biological methods were 0.43, 0.42, 0.65 and 1.41, respectively. The results suggest steam explosion and sulfuric acid pretreatment methods might be good alternatives at present state of technology and other pretreatment methods require research and development efforts to be competitive with these pretreatment methods.

Techno-economic analysis of different pretreatment processes for lignocellulosic-based bioethanol production

In this work, a method based on process synthesis, simulation and evaluation has been used to setup and study the industrial scale lignocellulosic bioethanol productions processes. Scenarios for pretreatment processes of diluted acid, liquid hot water and ammonia fiber explosion were studied. Pretreatment reactor temperature, catalyst loading and water content as well as solids loading in the hydrolysis reactor were evaluated regarding its effects on the process energy consumption and bioethanol concentration. The best scenarios for maximizing ethanol concentration and minimizing total annual costs (TAC) were selected and their minimum ethanol selling price was calculated. Ethanol concentration in the range of 2–8% (wt.) was investigated after the pretreatment. The best scenarios maximizing the ethanol concentration and minimizing TAC obtained a reduction of 19.6% and 30.2% respectively in the final ethanol selling price with respect to the initial base case.

ChemInform Abstract: An Evaluation of Dilute Acid and Ammonia Fiber Explosion Pretreatment for Cellulosic Ethanol Production

AbstractReview: 68 refs.

Optimal Production of Furfural and DMF from Algae and Switchgrass

In this paper, we develop a conceptual design of optimal integrated processes for the production of dimethyl furfural (DMF) and furfural from biomass, switchgrass and algae. The processes consist of four stages: (1) biomass pretreatment into intermediates such as oil and glucose from algae and glucose and xylose from switchgrass; (2) dehydration of the sugars; (3) hydroxymethyl furfural (HMF) and furfural purification; (4) synthesis of DMF out of HMF and fatty acid ethyl ester (FAEE) from oil in the case of using algae. We formulate mixed-integer nonlinear programming models so as to simultaneously optimize and heat integrate the processing of both raw materials. For switchgrass, the use of Ammonia Fiber Explosion (AFEX) pretreatment is recommended for a production of cost of DMF and furfural of $3/kg ($570 MM of fixed investment cost). For algae, the composition is 60% oil, 30% starch, and 10% protein to obtain 98 MMgal/yr of biofuels, 16% of DMF, at a cost of $1.98/gal ($693 MM of fixed investment). If ...

Long term storage of dilute acid pretreated corn stover feedstock and ethanol fermentability evaluation

This study reported a new solution of lignocellulose feedstock storage based on the distributed pretreatment concept. The dry dilute sulfuric acid pretreatment (DDAP) was conducted on corn stover feedstock, instead of ammonia fiber explosion pretreatment. Then the dry dilute acid pretreated corn stover was stored for three months during summer season with high temperature and humidity. No negative aspects were found on the physical property, composition, hydrolysis yield and ethanol fermentability of the long term stored pretreated corn stover, plus the additional merits including no chemicals recovery operation, anti-microbial contaminant environment from stronger acid and inhibitor contents, as well as the mild and slow hydrolysis in the storage. The new pretreatment method expanded the distributed pretreatment concept of feedstock storage with potential for practical application.

RETRACTED: An evaluation of dilute acid and ammonia fiber explosion pretreatment for cellulosic ethanol production

The challenge associated with cellulosic ethanol production is maximizing sugar yield at low cost. Current research is being focused to develop a pretreatment method to overcome biomass recalcitrance in an efficient way. This review is focused on two major pretreatments: dilute acid (DA) and ammonia fiber explosion (AFEX) pretreatment of corn stover and how these pretreatment cause morphological and chemical changes to corn stover in order to overcome the biomass recalcitrance. This review highlights the key differences of these two pretreatments based on compositional analysis, cellulose and its crystallinity, morphological changes, structural changes to lignin, enzymatic reactivity and enzyme adsorption onto pretreated solids and finally cellulosic ethanol production from the hydrolysate of DA and AFEX treated corn stover. Each stage of the process, AFEX pretreated corn stover was superior to DA treated corn stover.

Optimal Simultaneous Production of Biodiesel (FAEE) and Bioethanol from Switchgrass

In this work, we optimize the simultaneous production of biodiesel (fatty acid ethyl esters, FAEE) and ethanol from switchgrass. Two technologies are considered for switchgrass pretreatment: dilute acid and ammonia fiber explosion (AFEX). Next, enzymatic hydrolysis follows any of the pretreaments to obtain fermentable sugars, mainly xylose and glucose. We separate the lignin, and, with the sugars, we consider the production of bioethanol and/or FAEE. Based on a superstructure of alternatives, the problem is formulated as an mixed-integer nonlinear program (MINLP) with simultaneous optimization and heat integration. An economic evaluation is performed and water consumption is calculated. The simultaneous production of bioethanol and FAEE from switchgrass is shown not to be competitive at the current development of the conversion of sugars to FAEE, but it can become promising if the conversion from sugar exceeds 0.5. The optimal solution indicates bioethanol to be the preferred product because of its higher...

Exergy analysis of pretreatment processes of bioethanol production based on sugarcane bagasse

Bioethanol produced from LB (lignocellulosic biomass) is a renewable option to decrease fossil fuel demand. LB is considered the future feedstock for bioethanol production because of its low cost and availability. The production of bioethanol from LB involves different steps: pretreatment, hydrolysis, fermentation, and bioethanol recovery. Some pretreatments such as SE (steam explosion), LHW (liquid hot water), ammonia fiber explosion and acid hydrolysis treatment have been used frequently to remove lignin and to improve the saccharification of cell wall carbohydrates. In this work via exergy analysis biomass pretreatment methods to prepare LB for bioethanol production using two typical chemical compositions of sugarcane bagasse are evaluated. Four case studies for the following pretreatment technologies (A) SE, (B) Organosolv, (C) LHW and (D) SE + LHW are studied. Although high exergy values are obtained in all cases of this study (A) 93.2%, (B) 85.4%, (C) 94.1%, and (D) 95.1%, the values of destroyed exergy rate found for the cases analyzed using the raw material 2 are high compared to the input bagasse exergy rate, (A) 7.2%, (B) 24.8%, (C) 6.0%, and (D) 5.5%, highlighting the relevance of such processes in the overall exergy efficiency of second-generation bioethanol production routes.

Importance of chemical pretreatment for bioconversion of lignocellulosic biomass

Lignocelluloses are often a major or sometimes the sole components in different waste streams from various sources such as industries, forestry, agriculture and municipalities. It represents an as-of-yet untapped source of fermentable sugars for significant industrial use. Many physico-chemical, structural and compositional factors hinder the hydrolysis of components present in the biomass to sugars and other organic compounds that can later be converted into fuels. During the past few years, a large number of chemical pretreatment methods including lime, acid, steam explosion, sulfur dioxide explosion, ammonia fiber explosion, ionic liquid and others have been developed for efficient pretreatment of biomass. Many pretreatment methods have shown high sugar yields i.e. more than 90% of the theoretical yield from lignocelluloses. In this review, we discuss various chemical pretreatment processes, feasibility of the processes at industrial scale in terms of the mechanisms involved, advantages, disadvantages and economic assessment. It is not possible to define the best pretreatment method as it depends on many factors such as type of lignocellulosic biomass, process parameters, environmental impact, economical feasibility, etc. However, some of these chemical pretreatments have disadvantages such as formation of inhibitory compounds especially furfural and 5-hydroxyl methyl furfural (HMF).