Design and optimization of intensified biorefinery process for furfural production through a systematic procedure

Towards efficient and greener processes for furfural production from biomass: A review of the recent trends

As mentioned in several recent reviews, biomass-based furfural is attracting increasing interest as a feasible alternative for the synthesis of a wide range of non-petroleum-derived compounds. However, the lack of environmentally friendly, cost-effective, and sustainable industrial procedures is still evident. This review describes the chemical and biological routes for furfural production. The mechanisms proposed for the chemical transformation of xylose to furfural are detailed, as are the current advances in the manufacture of furfural from biomass. The main goal is to overview the different ways of improving the furfural synthesis process. A pretreatment process, particularly chemical and physico-chemical, enhances the digestibility of biomass, leading to the production of >70 % of available sugars for the production of valuable products. The combination of heterogeneous (zeolite and polymeric solid) catalyst and biphasic solvent system (water/GVL and water/CPME) is regarded as an attractive approach, affording >75 % furfural yield for over 80 % of selectivity with the possibility of catalyst reuse. Microwave heating as an activation technique reduces reaction time at least tenfold, making the process more sustainable. The state of the art in industrial processes is also discussed. It shows that, when sulfuric acid is used, the furfural yields do not exceed 55 % for temperatures close to 180 °C. However, the MTC process recently achieved an 83 % yield by continuously removing furfural from the liquid phase. Finally, the CIMV process, using a formic acid/acetic acid mixture, has been developed. The economic aspects of furfural production are then addressed. Future research will be needed to investigate scaling-up and biological techniques that produce acceptable yields and productivities to become commercially viable and competitive in furfural production from biomass.

Novel Hybrid Reactive Distillation with Extraction and Distillation Processes for Furfural Production from an Actual Xylose Solution

Furfural is only derived from lignocellulosic biomass and is an important chemical used in the plastics, agrochemical, and pharmaceutical industries. The existing industrial furfural production process, involving reaction and purification steps, suffers from a low yield and intensive energy use. Hence, major improvements are needed to sustainably upgrade the furfural production process. In this study, the conventional furfural process based on a continuous stirred tank reactor and distillation columns was designed and optimized from an actual aqueous xylose solution via a biomass pretreatment step. Subsequently, a reactive distillation (RD) and extraction/distillation (ED) configuration was proposed for the reaction and purification steps, respectively, to improve the process efficiency. RD can remove furfural instantly from the reactive liquid phase and can separate heavy components from the raw furfural stream, while the ED configuration with toluene and butyl chloride used as extracting solvents can effectively separate furfural from a dilute aqueous stream. The results showed that the hybrid RD-ED process using a butyl chloride solvent saves up to 51.8% and 57.4% of the total investment costs and total annual costs, respectively, compared to the conventional process. Furthermore, environmental impacts were evaluated and compared for all structural alternatives.

Value-Added Bio-Chemicals Commodities from Catalytic Conversion of Biomass Derived Furan-Compounds

The depletion of fossil resources in the near future and the need to decrease greenhouse gas emissions lead to the investigation of using alternative renewable resources as raw materials. One of the most promising options is the conversion of lignocellulosic biomass (like forestry residues) into bioenergy, biofuels and biochemicals. Among these products, the production of intermediate biochemicals has become an important goal since the petrochemical industry needs to find sustainable alternatives. In this way, the chemical industry competitiveness could be improved as bioproducts have a great potential market. Thus, the main objective of this review is to describe the production processes under study (reaction conditions, type of catalysts, solvents, etc.) of some promising intermediate biochemicals, such as; alcohols (1,2,6-hexanetriol, 1,6-hexanetriol and pentanediols (1,2 and 1,5-pentanediol)), maleic anhydride and 5-alkoxymethylfuran. These compounds can be produced using 5-hydroxymethylfurfural and/or furfural, which they both are considered one of the main biomass derived building blocks.

A review on commercial-scale high-value products that can be produced alongside cellulosic ethanol

The demand for fossil derivate fuels and chemicals has increased, augmenting concerns on climate change, global economic stability, and sustainability on fossil resources. Therefore, the production of fuels and chemicals from alternative and renewable resources has attracted considerable and growing attention. Ethanol is a promising biofuel that can reduce the consumption of gasoline in the transportation sector and related greenhouse gas (GHG) emissions. Lignocellulosic biomass is a promising feedstock to produce bioethanol (cellulosic ethanol) because of its abundance and low cost. Since the conversion of lignocellulose to ethanol is complex and expensive, the cellulosic ethanol price cannot compete with those of the fossil derivate fuels. A promising strategy to lower the production cost of cellulosic ethanol is developing a biorefinery which produces ethanol and other high-value chemicals from lignocellulose. The selection of such chemicals is difficult because there are hundreds of products that can be produced from lignocellulose. Multiple reviews and reports have described a small group of lignocellulose derivate compounds that have the potential to be commercialized. Some of these products are in the bench scale and require extensive research and time before they can be industrially produced. This review examines chemicals and materials with a Technology Readiness Level (TRL) of at least 8, which have reached a commercial scale and could be shortly or immediately integrated into a cellulosic ethanol process.

Combined optimization of N-terminal site-specific PEGylation of recombinant hirudin using response surface methodology and kinetic analysis

In this study, a combined optimization method was developed to optimize the N-terminal site-specific PEGylation of recombinant hirudin variant-2 (HV2) with different molecular weight mPEG-propionaldehyde (mPEG-ALD), which is a multifactor-influencing process. The HV2-PEGylation with 5 kDa mPEG-ALD was first chosen to screen significant factors and determine the locally optimized conditions for maximizing the yield of mono-PEGylated product using combined statistical methods, including the Plackett-Burman design, steepest ascent path analysis, and central composition design for the response surface methodology (RSM). Under the locally optimized conditions, PEGylation kinetics of HV2 with 5, 10, and 20 kDa mPEG-ALD were further investigated. The molar ratio of polyethylene glycol to HV2 and reaction time (the two most significant factors influencing the PEGylation efficiency) were globally optimized in a wide range using kinetic analysis. The data predicted by the combined optimization method using RSM and kinetic analysis were in good agreement with the corresponding experiment data. PEGylation site analysis revealed that almost 100% of the obtained mono-PEGylated-HV2 was modified at the N-terminus of HV2. This study demonstrated that the developed method is a useful tool for the optimization of the N-terminal site-specific PEGylation process to obtain a homogeneous mono-PEGylated protein with desirable yield.

Camellia oleifera shell as an alternative feedstock for furfural production using a high surface acidity solid acid catalyst

This paper focuses on the high-value transformation of camellia oleifera shell, which is an agricultural waste enriched in hemicellulose. An efficient catalytic route employing sulfonated swelling mesoporous polydivinylbenzene (PDVB-SO₃H) as catalyst in monophasic or biphasic solvents was developed for the conversion of raw camellia oleifera shell into furfural. The reaction parameters were evaluated and optimized for improving the furfural yield. It was found that the solvent greatly influenced the hydrolysis of camellia oleifera shells, and the highest furfural yield of 61.3% was obtained in "γ-butyrolactone + water" system when the feedstock-to-catalyst ratio was 2 for 30 min at 443 K. Camellia oleifera shell exhibited a high potential as feedstock to produce furfural in high yields. The outcome of this study provides an attractive utilization option to camellia oleifera shell, which is currently burned or discarded for producing a bio-based chemical.

Techno-economic assessment of hybrid extraction and distillation processes for furfural production from lignocellulosic biomass

BACKGROUND

Lignocellulosic biomass is one of the most promising alternatives for replacing mineral resources to overcome global warming, which has become the most important environmental issue in recent years. Furfural was listed by the National Renewable Energy Laboratory as one of the top 30 potential chemicals arising from biomass. However, the current production of furfural is energy intensive and uses inefficient technology. Thus, a hybrid purification process that combines extraction and distillation to produce furfural from lignocellulosic biomass was considered and investigated in detail to improve the process efficiency. This effective hybrid process depends on the extracting solvent, which was selected based on a comprehensive procedure that ranged from solvent screening to complete process design.

RESULTS

Various solvents were first evaluated in terms of their extraction ability. Then, the most promising solvents were selected to study the separation feasibility. Eventually, processes that used the three best solvents (toluene, benzene, and butyl chloride) were designed and optimized in detail using Aspen Plus. Sustainability analysis was performed to evaluate these processes in terms of their energy requirements, total annual costs (TAC), and carbon dioxide (CO₂) emissions. The results showed that butyl chloride was the most suitable solvent for the hybrid furfural process because it could save 44.7% of the TAC while reducing the CO₂ emissions by 45.5% compared to the toluene process. In comparison with the traditional purification process using distillation, this suggested hybrid extraction/distillation process can save up to 19.2% of the TAC and reduce 58.3% total annual CO₂ emissions. Furthermore, a sensitivity analysis of the feed composition and its effect on the performance of the proposed hybrid system was conducted.

CONCLUSIONS

Butyl chloride was found to be the most suitable solvent for the hybrid extraction/distillation process of furfural production. The proposed hybrid sequence was more favorable than the traditional distillation process when the methanol fraction of the feed stream was <3% and more benefit could be obtained when that fraction decreased.