Process, system and reactor for producing 2g bioethanol

Abstract

The present invention refers to an ultrasonic baffled hydrothermal (UBH) reactor for the pretreatment of lignocellulosic biomass, using rotating baffles (180) and blades (182) driven by a motor (73), surrounding heating coils (181) and ultrasonic probes (177, 123). The invention also refers to immobilized cellulase using metal-organic frameworks (MOF). This invention also refers to the counter-current saccharification process. The invention further refers to a thermosiphon which can be used couples with a falling film in a distillation. Additionally, it also refers to a process for producing bioethanol using said UBH reactor, the immobilized cellulase in a counter-current process and a falling film e coupled with the thermosiphon. A system for producing bioethanol comprising the UBH reactor, a saccharification counter-current process, falling films and a thermosiphon is also presented. The uses of the UBH reactor, the enzyme and the thermosiphon are also proposed.

Description

PROCESS, SYSTEM AND REACTOR FOR PRODUCING 2G BIOETHANOLFIELD OF INVENTION

[0001] The invention relates to the field of energy and fuel, more precisely an improvement of the production levels and economic conditions of lignocellulosic 2G bioethanol. 2G bioethanol, or second-generation bioethanol, is a type of biofuel produced from non-food biomass, such as agricultural residues, forestry waste, or dedicated energy crops like switchgrass. Unlike first-generation bioethanol, which is derived from food crops such as sugarcane or corn, 2G bioethanol focuses on utilizing lignocellulosic materials — plant materials that are composed of cellulose, hemicellulose, and lignin.

[0002] The present invention refers to a process and system for producing bioethanol by an ultrasonic baffled hydrothermal reactor for the pretreatment of biomass.

[0003] The present invention also relates to encapsulated enzymes and their production as part of this process.

[0004] The present invention also relates to use of counter current saccharification system in the hydrolysis of pretreated biomass, as part of this process.

[0005] The present invention relates to a thermosiphon which can be coupled with a distiller for a distilling system for executing the process.

[0006] The reactor, the enzymes, the saccharification system and thermosiphon can be used in the production of lignocellulosic 2G bioethanol.BACKGROUND OF THE INVENTION

[0007] According to “OECD-FAO Agricultural Outlook 2020-2029”, world bioethanol production is projected to grow from 122 billion liters (over the base period) to 143 billion liters by 2028. Notably, the leading biofuel producers are the United States of America, Brazil, Indonesia, Germany, China, Thailand, and Spain. Additionally, according to forecasts of the International Energy Agency (IEA), the production of biofuels will reach760 million tons of oil equivalent in 2050.

[0008] Before the COVID-19 pandemic, global bioethanol production was expected to increase to 130 billion L by 2024. In over 70 countries, regulatory mandates for biofuels have already been established. For instance, in China, a nationwide mandate to achieve a 10% renewable ethanol content in transportation fuels shall be established with strong governmental support for non-food-based biofuels and second-generation ethanol plants. India’s administration mandated twelve second-generation ethanol plants to be built. In the European Union (EU), the Renewable Energy Directive (RED) II defined an advanced biofuel target and established that conventional food-based biofuels, including bioethanol, will be limited at a maximum of 7% of final consumption of energy in the road and rail transport sector in 2030.

[0009] In 2020 the European Commission updated its First Circular EconomyAction Plan launched in 2015. Among the actions derived from the EU's agenda for sustainable growth, the recast Renewable Energy Directive (EU) 2018 / 2001 laid down a target for advanced biofuels contributing 3.5% of the total transport sector energy. These biofuels must be produced from feedstocks like lignocellulosic biomass (bagasse, straw, or forestry waste).

[0010] The production of biofuels from lignocellulosic biomass comprises several steps, such as pretreatment, enzymatic saccharification, and microbial fermentation. For achieving effective enzymatic saccharification of cellulose and, consequently, a higher release of fermentable sugars, a pretreatment step is indispensable.

[0011] By disrupting the lignocellulosic matrix, pretreatment exposes cellulose and makes it more reactive towards cellulases [1]. During the pretreatment, the complex polymeric biomass structures are altered by breaking the lignin seal, removing lignin and / or increasing its porosity. In order to be viable, the pretreatment should meet the following requirements: low energy demand and overall costs, efficient and rapid release of sugars in the subsequent hydrolysis, reducing carbohydrate degradation and avoiding the formation of inhibitory compounds (e.g., acids, furans and phenols) [2, 3].

[0012] Due to limited non-renewable energy sources and demands to reduce CO2 emissions, the chemical industry seeks more sustainable production routes for the manufacture of chemical compounds such as liquid fuels. Lignocellulosic biomass contains cellulose (25-40%), hemicellulose (15-25%) and lignin (15-30%) as major components. Among forms of plant biomass, lignocellulosic biomass derived from any agricultural waste streams, such as cereal straw and wood residues are particularly well suited forconversion to biofuels because of their availability, low cost, and environmentally sound production. Ethanol produced from non-food products or food waste and other lignocellulosic biomass is referred to as "second generation ethanol".

[0013] The preparation of ethanol from cellulose is an important research topic all over the world. The production of ethanol from a large amount of cheap cellulose is the trend of future development. However, there are still many key technical bottlenecks in this area that have not yet been well solved.

[0014] Cao Lianying et. al. in "Research Progress on Lignocellulosic Ethanol Key Technologies" pointed out that the cost of producing cellulosic ethanol based on lignocellulosic biomass remains high. Instead, the main reason for this lies in the limitations of the following three key technologies: (1 ) high-efficiency straw pretreatment technology, (2) low-cost industrial production of cellulase technology, (3) optimization of mixed sugar ethanol fermentation technology [5].

[0015] Many pilot lines or production lines that have been established, especially domestic pilot lines or production lines, are currently in a "sleepy" state. The reason is that, from the perspective of local technology, there are mainly problems such as incomplete cellulose purification, large pollution load of waste mash, and difficulty in treatment.

[0016] In general, the production of 2G bioethanol from lignocellulosic sources faces a major limitation. These two limitations include low production efficiency and high production cost.

[0017] The development of sustainable and non-polluting energy is a technological trend. A large number of lignocellulosic wastes such as straw and corncob are produced in agricultural production every year. The main components of lignocellulosic materials are cellulose, hemicellulose, lignin, and a small amount of ash. Although the cellulose components can be enzymatically hydrolyzed and saccharified by cellulase to obtain glucose, glucose can be treated by biological fermentation to produce cellulosic ethanol, considered a clean fuel.

[0018] As a new type of biomass energy, fuel cellulosic ethanol has dual attributes such as renewable and environmentally friendly and is the only renewable energy that can be stored and transported. Currently, developed countries in Europe and the United States and developing countries such as Brazil have widely used fuel cellulosic ethanol.

[0019] In combined pretreatments, biomass components are usually recovered separately in different streams. Combined pretreatments seem to increase the efficiency ofthe process compared to the individual technologies; they allow the obtention of high sugar yields with milder operation conditions and require lower solvent and enzyme amounts, thus improving the cost and sustainability of the final product. Nowadays, Combination methods such as ultrasonic-assisted technique as well as hydrothermal and alkaline have been proposed.

[0020] The most important step in the production of lignocellulosic 2G bioethanol is the conversion of cellulose and hemicellulose to soluble sugars. Recently, much attention has been paid to the enzymatic hydrolysis of cellulose. In enzymatic hydrolysis, cellulase performs the hydrolysis of cellulose and hemicellulose to sugars. The glucose obtained from the hydrolysis step can be converted to the wide range of value-added chemicals in addition to bioethanol.

[0021] Cellulose hydrolysis step is a basic and costly step in the production process of lignocellulosic 2G bioethanol because cellulase stability in industrial processes requires difficult and harsh conditions. Therefore, cellulase recovery is one of the vital processes to create sustainable and cost-effective production of 2G bioethanol. On the other hand, since various inhibitors such as weak acid, furan derivatives and phenols are produced during the pretreatment process, this causes a greater need for cellulase in the hydrolysis step. As a result, finding a way to protect cellulase against these inhibitors and eliminating the extensive steps of separation and washing of cellulose-rich solids from the pretreatment stage and using the whole slurry from the pretreatment as a substrate in the enzymatic hydrolysis stage is attractive and considered economically.

[0022] To solve the aforementioned drawbacks of free enzymes, many approaches, such as immobilization, artificial modification, protein and enzyme engineering, solvent engineering and directed evolution of enzymes, have been widely adopted.

[0023] An important approach for the protection and recovery of cellulase is immobilization of it on a substrate as a protector against the effects of the environment. Cellulase immobilization is a powerful and simple tool to solve the problem of using it as an industrial catalyst. Fortunately, immobilized cellulase has a similar and sometimes even better performance than free cellulose (for example, in the presence of organic solvents) in the process of hydrolysis of lignocellulosic biomass.

[0024] In the present invention, an attempt has been made to significantly improve the economic and technical efficiency of the lignocellulosic 2G bioethanol production process by focusing on the two major limitations and creating a system andreactors for executing this process.TASK OF THE INVENTION

[0025] The task of this invention is it to create an improved process, system for producing 2G bioethanol, with higher efficiency, at lower cost and with more stability of the process, that is by reducing the disadvantages of conventional processes. Furthermore, it is a task of this invention to create an advanced reactor for producing 2G bioethanol according to the proposed process and system.

[0026] Thus, the purpose of the invention over all is to increase production and economic efficiency as well as to reduce the disadvantages of conventional processes.

[0027] A first aspect of the present invention is to provide an ultrasonic baffled hydrothermal (UBH) reactor for the pretreatment of lignocellulosic biomass.

[0028] A second aspect of the present invention is to provide immobilized enzymes using metal-organic frameworks in Counter-current saccharification system.

[0029] A third aspect of the invention is to present a method for producing an enzyme complex.

[0030] A fourth aspect oof the present invention is to provide a thermosiphon for distilling processes .

[0031] A fifth aspect of the present invention it to provide a distillation system.

[0032] A sixth aspect of the present invention is to provide process for producing2G bioethanol.

[0033] A seventh aspect of the present invention is to provide a system for producing 2G bioethanol comprising the UBH reactor, a Counter-current saccharification process, falling films and a thermosiphon.

[0034] An eighth aspect of the present invention is the use of the UBH reactor.

[0035] A ninth aspect of the present invention is the use of the thermosiphon .

[0036] A tenth aspect of the present invention is the use of Counter-current saccharification process with Cellulase-at-MOF.

[0037] In view of that, the present invention aims to improve the production process of lignocellulosic 2G bioethanol by creating approaches and systems for the pretreatment, hydrolysis and distillation steps. Additionally, it reduces production costs including costs related to enzymatic hydrolysis, pretreatment and fermentation processes. In the pretreatment stage, a three-part reactor with an ultrasonic homogenizer was used to increase the de-lignification efficiency. In the hydrolysis stage, a series of operations,including the production of consumable enzymes and the use of Cellulase-at-MOF in counter-current saccharification technique, will lead to a significant reduction in enzyme- related costs. The distillation step also reduces the energy consumption of the process by using the Falling film improved with Thermosiphon cooler.SUMMARY OF INVENTION

[0038] The task of this invention is solved by a process for producing 2G bioethanol comprising the steps of claim 1 , by a system according to claim 9 and by an ultrasonic baffled hydrothermal (UBH) reactor for the pretreatment of biomass as crucial part of the process, comprising the technical features of claim 10, and furthermore by a thermopsiphon cooling system according to claim 16 and a counter current hydrolysis reactor according to claim 18, all part of the system.BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a representation of the UBH reactor seen from the outside.

[0040] Figure 2 is an open diagonal representation of the UBH reactor which exemplifies the interior of the reactor with the baffles, the ultrasonic probes and the fin.

[0041] Figure 3 is a top view of the interior of the UBH reactor with the baffles, the ultrasonic probes and the fin.

[0042] Figure 4 illustrates a first embodiment of the system for producing the 2G bioethanol with all the apparatus and the steps of the process for producing the 2G bioethanol.

[0043] Figure 5 illustrates the falling film coupled with the thermosiphon.

[0044] Figure 6 illustrates a diagonal view of the falling film coupled with the thermosiphon.

[0045] Figures 7A, 7B, 7C illustrate details of the thermosiphon.

[0046] Figure 8 shows the distilling system with the molecular sieve.

[0047] Figure 9 shows the spectrum of the effect of the baffle to the lignin content.

[0048] Figure 10 shows spectrum of the effect of the ultrasonic and temperature to the lignin content.

[0049] Figure 11 shows the FTIR peaks corresponding to the functional groups of lignocellulosic components according to table 5.

[0050] Figure 12 shows the FTIR spectrum for the baffle effect tests.

[0051] Figure 13 represents the FTIR spectrum for the different combinations between ultrasound, baffle and temperature.

[0052] Figure 14 comprises images of the scanning electron microscopy of the untreated rice straw.

[0053] Figure 15 comprises images of the scanning electron microscopy of the rice straw treated without baffle (top), the baffle of the present invention (middle) and conventional baffle (bottom).

[0054] Figure 16 comprises images of the scanning electron microscopy of the rice straw treated at 80QC (top left), 80QC+ultrasound (top right), 100QC (middle left), 100QC+ ultrasound (middle right), 120QC (bottom left) and 120QC+ ultrasound (bottom right).

[0055] Figure 17 shows a 3D schematic of the CCH system.

[0056] Figure 18 comprises images of the scanning electron microscopy of MAF-7.

[0057] Figure 19 comprises images of the scanning electron microscopy of Cellulase@MAF-7.

[0058] Figure 20 comprises images of the XRD pattern of MAF-7.

[0059] Figure 21 comprises images of the XRD pattern of Cellulase@MAF-7.DETAILED DESCRIPTION OF THE INVENTION

[0060] Ultrasonic assisted hydrothermal pretreatment is used in 2G bioethanol production to increase the efficiency of biomass conversion into biofuel. Moreover, due to the lack of dangerous and toxic chemical agent usage, it can be considered a green replacement for conventional pretreatment methods.

[0061] Lower energy inlets are required when the hydrothermal process is integrated with ultrasonic waves. Therefore, the pretreatment is enhanced to be more environmentally friendly because the ultrasonic waves disrupt the lignocellulosic matrix, making the biomass more amenable.

[0062] In view of that, an ultrasonic baffled hydrothermal (UBH) reactor as shown in figures 1 to 3 is being claimed. The present invention refers to an UBH reactor for the pretreatment of biomass, wherein the UBH reactor comprises: a reactor body 172 coupled to a flanged-type lid 176, wherein the flanged-type lid 176 comprises a plurality of inlets 66 for the attachment of:- an external heating / cooling inlet,- a shaft aligned with the center of the flanged-type lid 175; and- a plurality of ultrasonic probes 123; wherein the reactor body 172 comprises: a. an inlet 66 for the untreated material; b. a bottom part with an outlet 174 for the reactor product; c. a plurality of heating / cooling coils 181 inside the reactor body; d. an air pressure inlet / outlet placed on the top external side of the reactor body 172; e. an agitator shaft 175 inside the reactor body 172, the agitator shaft 175 connected to a motor 73 and comprising:- an agitation system at the bottom of the agitator shaft 175;- curved baffles 180 above the agitation system; wherein the curved baffles 180 are configured to prevent the swirling / vortex of the materials in the reactor and increase mixing rate.

[0063] In the present invention, the UBH reactor consists of cylindrical and torispherical parts, preferably wherein the lid and the bottom are torispherical and the middle of the reactor is cylindrical. The shaft 175 of the reactor is also cylindrical and has a space inside that lets the agitator shaft 175 spin freely.

[0064] In the present invention the reactor comprises 2 to 5 ultrasonic holders 177, preferably three ultrasonic holders 177 symmetrically distanced equally between each other.

[0065] In the present invention, the ultrasonic holders 177 are proportional to the number of baffles 180. The probes 123 must also be set in the middle of the baffles 180 from up to down view.

[0066] Each ultrasonic holder 177 comprises at least one flange. Additionally, the feed inlets 66 and lid comprise flanges. Each flange comprises about 8 to about 16 equidistant bolts, preferably the flanges of the ultrasonic holder 177 comprise 8 bolts, the flanges of the feed inlet comprise 12 bolts and the flange of the lid comprises 16 bolts. The ports of the reactor body 172 and lid are airtight flanged sealed by the flanges of the ultrasonic holders 177.

[0067] In addition to that, the number of bolts for flanges is regarded to the availability and better sealing so it can be changed but the specifications must be contained. For example, if the lid flanges are going to be changed it has to be still air tight.

[0068] The ultrasonic probes 123 of the reactor reduce the production of inhibitors bylowering the pretreatment temperature. It requires lower energy inlets because the ultrasonic waves disrupt the lignocellulosic matrix, making the biomass more amenable. Ultrasound waves increase access to the porous structures by creating microscopic bubbles.

[0069] Additionally, the lid of the ultrasonic hydrothermal reactor comprises two identical or different inlets 66, preferably identical.

[0070] In the present invention, the heating / cooling coils 181 are wrapped around the reactor in about 5 to about 20 revolutions, preferably about 10 to about 15 revolutions, most preferably 13 revolutions with an inlet and an outlet for steam. The revolution numbers are selected to achieve the maximum heating surface.

[0071] The UBH reactor further comprises a shell. Said shell comprises a heat jacket with an inlet and outlet 183 for oil in case it is necessary to control the inner temperature of the reactor by increasing or reducing the temperature.

[0072] The shell additionally comprises at least 2 foundation arms for lifting or legs. Usually, it comprises from about 2 to about 6, preferably about 4 legs and / or arms.

[0073] For the present invention, the agitation system comprises a fin with about 2 to about 6 blades 182, preferably 4 blades 182. The fin can be diagonal.

[0074] In the present invention, the UBH reactor comprises from about 3 to about 5 baffles 180, preferably 3 baffles 180, wherein the curved baffles 180 comprise holes in each of them. The freedom of movement caused by the agitation of the lignocellulosic contents are achieved due to the fact that the baffles 180 do not allow turbulence and vortex in the system. The shape of the holes is circular and are related to the free movement of the lignocellulosic content in the reactor, so these baffles 180 stop the turbulency in the system and also allow the parts to move freely. The baffles 180 are equally distanced, and each baffle 180 has about 5 to about 10 holes horizontally, which the number of horizontal holes is directly relevant to the baffle 180 width. Each baffle 180 has also from about 15 to 25 holes vertically, which the number of vertical holes is directly relevant to the baffle 180 length.

[0075] The baffles 180 of the present invention, in addition to preventing the swirling / vortex of the materials in the reactor, which takes place along with complete mixing in the three parts of the reactor, increase the efficiency of the mixing rate and reduce the operating time.

[0076] The UBH reactor of the present invention can be used in a vast number of plants such as petrochemical plants, biofuel plants, and other lignocellulosic processes.

[0077] The present invention also relates to a cellulase immobilized with metal-organic frameworks (MOF) for use in the hydrolysis of cellulose.

[0078] The immobilized cellulase of the present invention is an infiltrated or encapsulated cellulase, preferably encapsulated.

[0079] Additionally, in the present invention the MOF is selected from the group comprising ZIF-7 (Zn), MOF-199 (Cu) and MAF-7 (Zn).

[0080] During the production of 2G bioethanol, one of the most important steps is the hydrolysis / saccharification step. In enzymatic hydrolysis, cellulase performs the hydrolysis of cellulose and hemicellulose to sugars. Cellulase is the term used for a set of enzymes including endo-[3-1 ,4-glucagane (EG), cellobiohydrolase (CBH) and [3-glucosidase (|3-G). Of these three groups of enzymes, EG and CBH convert cellulose to cellobiose and then p-G converts cellobiose to glucose.

[0081] Metal-organic frameworks (MOFs) are hybrid porous materials. More specifically, these hybrid porous materials comprise a crystalline structure consisting of inorganic metals as node and organic compounds as linkers. MOFs can be used effectively to immobilize and protect enzymes. These structures have different applications such as gas absorption, sensors and heterogeneous catalysts due to their unique properties such as high porosity (due to lack of wall in scaffold-like structure), high surface area and good temperature stability. Also, these properties of MOFs result in thermal and chemical protection and exceptional adsorption capacity for enzymes.

[0082] Cellulase immobilization using MOF occurs through precipitation method and encapsulation of cellulase in MOF pores. However, due to the microporous structure of MOFs, cellulase is often immobilized only on its outer surface and its porosity is not actually used. Nevertheless, "in situ encapsulation" is an acceptable approach to placing cellulase inside MOF cavities because it significantly increases the loading and binding of cellulase minimizing its leaching and wastage during the process.

[0083] In addition to that, placing cellulase inside the MOF pores causes favorable structural defects in the backbone of the frameworks and as a result, the average pore size increases and the MOF is improved for the cellulose hydrolysis process. In general, water-stable MOFs are resistant to high temperatures and extreme pH (high and low) conditions, what is desirable for the saccharification process. The MOFs used in various studies for cellulase immobilization and cellulose hydrolysis are ZIF-8 (Zn), UiO-66-NH2 (Zr), MIL-100 (Fe), MIL-127 (Fe), Zn-mlm, Cu (PABA), Zr (MP-UIO-66), ZIF-8 hybrid membrane, UIO-66-Zr, MOF based on zinc (Zn-mlm), Uio-66-NH2, MAF-90, MIL-101 (Cr),MIL-53 (Al) and MOF-199 (Cu).

[0084] A MOF based on mesoporous Zr (MP-UIO-66) has been used to immobilize cellulase, and it has been shown that the catalytic efficiency and affinity of the substrate and catalyst are higher than the catalytic efficiency and affinity of the substrate and free cellulase.

[0085] UIO-66-Zr has been used to stabilize cellulase and it was observed that after 6 cycles of use, 80% of the enzyme activity was still maintained.

[0086] Cellulase enzyme was immobilized on a ZIF-8 hybrid membrane. Compared to free cellulase, immobilized enzymes retain their enzymatic activity at high temperature and pH.

[0087] A mesoporous MOF based on zinc (Zn-mlm) has been used to stabilize cellulase enzyme. Cellulase @Zn-mlm maintains its enzyme activity up to 65% at pH=8. While this value is only 10% for free cellulase. Also, 77% of the enzyme activity is preserved after 4 cycles.

[0088] Cellulase enzyme is stabilized on Uio-66-NH2 magnetic core-shell. This system can be restored up to 5 consecutive periods. Catalysts obtained from immobilization of cellulase on Uio-66-NH2 were produced and showed high thermal and pH resistance. In this study, 85% of enzyme activity was preserved at 80°C. Also, after 10 cycles of use, 75% of the initial activity has been preserved.

[0089] MAF-7 has been used in a catalytic system to stabilize magnetic nanoparticles and lactate dehydrogenase (LDH) enzyme. This system has shown more resistance to acid, alkali, temperature and high solvents [4]. It has been shown that the enzyme activity of catalase or urease stabilized by MAF-90 and MAF-7, which are hydrophilic, is preserved in harsh environmental conditions (high temperature, denaturing or proteolytic agents, etc.), in While ZIF-8 does not provide resistance [5].

[0090] In addition to the crystallinity, porosity, and active sites in MOFs, they are referred to as "enzyme-like" materials with structures similar to those found in natural metalloproteinase. In view of that, MOFs are used as ideal catalysts for biochemical reactions such as cellulose hydrolysis.

[0091] Metal nodes and organic linkers in MOFs can be synthesized during synthesis or post-synthetic modifications with functional groups (such as sulfonic acid, amines, amides, etc. as acid and base centers) and metals (as redox sites) modified and provide a special environment for the hydrolysis reaction of cellulose biomass. It should be noted that most common MOFs such as MOF-5 and MOF-199 are manufactured by various companies, including BASF, on an industrial scale.

[0092] Compared to free cellulase, immobilized cellulase showed better tolerance to formic acid and vanillin, two typical inhibitors found in lignocellulosic pre-hydrolysates. It is necessary to recover and reuse the cellulase after hydrolysis in an attempt to make the lignocellulosic biorefinery more economically viable. Therefore, immobilization is a powerful and simple tool to resolve the problems with using enzymes as industrial catalysts, i.e., enzyme recyclability, enzyme stability, enzyme selectivity as well as decrease of inhibition by compounds present in reaction medium.

[0093] MOF materials have the advantages of high porosity and high specific surface, so its application is in full swing, especially in the field of enzyme immobilization. MOFs possess high surface areas and large pore volumes that facilitate the transport of enzyme substrates through porous network. It also can offer exceptional thermal and chemical protection for enzymes, compared to other traditional porous materials such as mesoporous metal oxides and silica.

[0094] The metal ions forming the MOF materials can be chosen according to their low price, low toxicity and, of course, their possibility for generating MOFs at room temperature in water, in order to close the cycle of economic, environmental and energy sustainability in the synthesis, application and disposal life cycle.

[0095] The stability of enzymes is relatively low, particularly their tertiary structure which gives them their biocatalytic performance. Even limited changes in temperature or acidity, the presence of alien chemical species in the media or, of course, the use of a nonaqueous solvent, could lead to the inactivation of the enzymes. Therefore, one-pot immobilization of enzymes implies that the support must be capable of being formed in the presence of enzymes under conditions that do not alter their structure / activity.

[0096] The approach, called ‘biomimetic mineralization’, was carried out in the absence of capping agents. In this methodology, the enzyme induces the growth of the MOF in water, in such a way that the enzyme ends up embedded inside a MOF crystal. A general comparison of enzyme immobilization methods using MOFs is shown in Table 1.Table 1 - Comparison of the Enzyme immobilization methods

[0097] The present invention also related to a method of synthesis of the cellulase-at-MOF. The method is carried out through the following general route: a) preparing an aqueous solution of metal salt; along with 2mg cellulase / mL of citrate buffer and 50% by weight of Polyvinylpyrrolidone; b) preparing an aqueous solution of organic ligand c) adding solution (a) slowly and dropwise to solution (b) which is being stirred at room temperature; d) centrifuging and washing the structures after about 6 to about 12 hours, e) Finally, drying and storing the structures.In the present invention, the structures are dried by a freeze-dryer and storesin a refrigerator at a temperature of about 0QC to about 6QC, preferably about 2QC to about 5QC, most preferably about 4QC.

[0098] The enzyme can be acquired from different companies. However, it is also possible to use enzymes produced using fungal species.

[0099] In general, the cost of the enzyme accounts for a large part of the costs of the lignocellulosic 2G bioethanol production process. In the present invention, in addition to producing the enzyme within the system itself, and the use of MOFs to recover and stabilize them, a counter-current saccharification method has been used as the basic system in the enzymatic hydrolysis step, which reduces the enzyme consumption by more than 15 times compared to other common methods. As it is known, this feature greatly reduced the production cost of lignocellulosic 2G bioethanol. On the other hand, by placing cellulase enzyme in MOF, it will be protected against environmental shocks.

[0100] The cellulase-at-MOF is used in hydrolysis / saccharification process. More precisely it can be used in combination with a counter-current system (CCH) to convert cellulose into sugars, such as glucose.

[0101] The present invention relates to a thermosiphon heat-pipe condenser 103, wherein the thermosiphon comprises: an upper chamber 102 and a bottom chamber 102, the top chamber comprising: a top wall, a bottom wall and two lateral walls, a plurality of fans fitted to the top wall 161 ; a plurality of refrigerant pipes inside the upper chamber 160 and attached to both upper chamber lateral walls, said refrigerant pipes 160 go through the upper chamber 102 bottom wall and enter the bottom chamber 102 through the bottom chamber top wall; the bottom chamber comprising: a top wall, a bottom wall and two lateral walls,- an inlet for vapor 159;- an outlet for the liquids 163;- a pipe with a plurality of spirals connecting the inlet and the outlet 160;- the refrigerant pipes attached to both bottom chamber lateral walls 160.

[0102] The thermosiphon of the present invention is passive cooling system that relies on gravity and density to circulate a refrigerant fluid rather than a capillary wick structure. These benefits of this equipment are pacts, water usage, and long run time without utility.

[0103] In an embodiment the upper chamber bottom wall is connected to or the same as the bottom chamber top wall. In another embodiment there is an open space between the upper chamber and the bottom chamber wherein the refrigerant pipes are in contact with the air.

[0104] Usually, thermosiphons are responsible for preheating the distiller (e.g. falling films). However, in the present invention the thermosiphon is used as a condenser and is responsible for cooling the distiller.

[0105] For the distillation of viscous fluids and slurry, a valid option is the usage of falling film towers. This process is simple and similar to conventional distillation towers but with comprises differences. For instance, hot steam is used to heat the feed instead of using a boiler at the bottom of the column. The present invention also refers to a distillation system comprising: a falling film evaporator 154 with an inlet for the low concentration ethanol 155, a top outlet 105 and a bottom outlet 157, wherein the bottom outlet 157 transports the residues and the top outlet transports a gaseous 2G bioethanol; a thermosiphon 103 configured to convert the gaseous ethanol into liquid ethanol and to cool the evaporator; optionally an additional purifier to increase the purity of the product.

[0106] Figure 5 shows one embodiment for the distillation system comprising:- Falling film evaporator comprising- Feed input 155;- Hot steam input 106;- Falling film tower shell 154;- Steam output 105;- Sludge / slurry output 157;- Water particle separation from vapor 158;- Thermosiphon condenser 103 with the distillate output 163.Optionally, as shown in Figure 8 it may also comprise- A fluidized bed purified comprisinga molecular sieve 164 recovery designed to work under vacuum;- a molecular sieve 164 comprising silicone grooves and designed to work under pressure.

[0107] The distillation system of the present invention can be used in a vast number of plants such as petrochemical plants, biofuel plants such as 2G bioethanol, and other processes which require a distillation step.

[0108] The present invention also relates to a process for producing 2G bioethanol, wherein the process comprises the steps of:I. obtaining the raw material;II. physically pretreating the raw material;III. hydrothermally pretreating the material that leaves step I, forming a mix of lignin, cellulose and hemicellulose;IV. converting the cellulose and hemicellulose into sugars in the presence of enzyme solution;V. fermenting the sugars into a diluted alcohol;VI. distilling the alcohol; andVII. obtaining the 2G bioethanol product.

[0109] For the present invention, the step III of hydrothermally pretreating the material comprises converting the material in an ultrasonic baffled hydrothermal (UBH) reactor as previously described.

[0110] The following paragraphs describe the steps of the process.Step I - Obtaining the raw material

[0111] For the present invention, the raw material and biomass have similar meanings. Among the possible raw materials, agricultural and forestry wastes not limited to but including as sugar cane bagasse, wheat straw, rice straw, corn stalks, forest residues, fruit and vegetable wastes, and similar wastes contain abundant biomass energy.Step II - Physical treatment

[0112] In the present invention, step II starts with the transport of the raw material. A combination of different machines can be used in view of the raw material and its necessity to be shredded, stored, or dried.

[0113] In one possible embodiment, step II comprises the substeps of:A’- drying the raw material to produce a dry straw;B’- storing the dried material in silos; andC’- crushing extruding the dried material with an extruder.In the storage silos of substep B’, raw materials are pressed and then stored in optimal environmental conditions to protect them from decay for a longer period of time. Substep A’ can be performed in a rotational dryer, in a vertical dryer or in open air.In this embodiment, the compressed straw is crushed into small particles by the extruder before entering the main pre-treatment reactor to increase the available surface area and thus the process efficiency.In the present invention, embodiment II A’-B’-C’ is a preferred embodiment.Step III - Hydrothermal treatment

[0114] During step III, the cellulose and wet lignin are further separated, and the black liquor containing lignin enters its own section for lignin separation, wherein it can be dehumidified in a decanter while remaining solid containing cellulose and cellulose enters step IV.

[0115] Different treatments have different advantages and disadvantages. Therefore, the use of combined methods can help to create overlap between different methods. For this purpose, a hydrothermal reactor combined with alkaline and ultrasonic methods is proposed.

[0116] The material enters the UBH reactor 172. In this reactor, materials are exposed to hydrothermal conditions and ultrasonic waves. Also, by dividing the internal space of the reactor, the transfer of heat and energy required for ultrasound production is facilitated.

[0117] In this process, after the biomass / raw material is processed in step I, same is directed to the UBH reactor 172. In this reactor, the mix is exposed to critical hot water at a temperature up to about 150QC, preferably about 120QC to about 145QC, most preferably about 130QC to about 140QC. Said temperature enhances the process but reduces the destruction of cellulosic structures. Conventional methods use 170QC to 180QC, therefore in the present process less destruction of cellulosic structures is observed.

[0118] Pressure is also applied up to about 13.6 atm (1 ,27x107Pa), preferably about 7 atm (7.1 x105Pa) to about 12 atm (1.2x106Pa), most preferably about 9 atm (9.1x105Pa) to about 10 atm (1 x106Pa).

[0119] In the present invention, the pressure of steam / water and the temperature break down the biomass structure and make it more amenable to subsequent enzymatic conversion.

[0120] Additionally, the UBH reactor 172 must operate in batch because it must be airtight sealed due to high pressure and temperature usage. The operation time is at least about 30 minutes.

[0121] Due to the lower alkali content than under normal alkaline pretreatment (from about 0.01 M to about 0.1 M), lignocellulosic structures such as hemicellulose and cellulose suffer less damage, but lignin removal is greater than that of the liquid hot water (LHW) pretreatment without NaOH. NaOH also prevents the formation of acidic inhibitors (furfural, hydroxymethylfurfural (HMF) and acids) and, while reacting with hemicellulose acetates, increases access to the carbon structure for the enzymatic hydrolysis step.

[0122] To avoid acidification of reaction conditions due to high temperature, we use NaOH solution. The consumption of this solution is only to the extent that the reaction medium remains neutral. Therefore, compared to the hydrothermal method, fewer inhibitors are produced, while less chemicals are used in the consumption of chemicals compared to conventional chemical methods.

[0123] The ultrasonic probs 123 are also responsible for the reduced production of inhibitors by lowering the pretreatment temperature. It requires lower energy inputs because the ultrasonic waves disrupt the lignocellulosic matrix, making the biomass more amenable.

[0124] Additionally, the ultrasound waves increase access to the porous structures by creating microscopic bubbles and improves the efficiency of enzymatic hydrolysis, thus covering the reduction in efficiency resulting from the temperature constraint created for the reactor. Ultrasonic waves are generated by agitators inside the reactor body. By dividing the inner space of the reactor by baffles, the ultrasonic energy will interact with the substrate more optimally.

[0125] The baffles 180 of the reactor enhance heat transfer while improving fluid distribution. The baffle as described in the present invention prevents vortex and increases the mixing rate.

[0126] It should be noted that by using the vacuum recovery method, the consumption of chemicals, water and total energy can be saved to a desirable level. In addition to that, using a single reactor reduces the overall construction and maintenance costs.

[0127] In one embodiment of the invention shown in Figure 4, the products of the hydrothermal pretreatment are separated by a centrifuge and, while cellulose and hemicellulose are sent to step IV, the wet lignin is decanted and can be used in otherproducts (step VII).

[0128] The lignin can be also recovered from the black liquor by precipitation, that is, by lowering the pH with CO2, dewatered using filter press and redissolved in water and acid. The slurry is once again dewatered and washed to produce a high-purity lignin stream.

[0129] Lignin is one of the most important by-products of the 2G bioethanol production process. Lignin can be used to produce a variety of products in a various industry, some of which are carbon bibbers, phenolic compounds, activated carbon, fuels and bioplastics.

[0130] The water removed from the dehydrator tanks is returned to the pretreatment reactor to save water consumption.Step IV - Hydrolysis / Saccharification

[0131] In step IV, the cellulose and hemicellulose are converted to glucose and xylose via saccharification. The saccharification of step IV is performed in about 3 to about 8, preferably about 3 to about 5 saccharification counter-current reactors with a produced or commercially available cellulase enzyme. The enzymes can be a metal-organic framework-cellulase complex (cellulase-at-MOF). For the invention, the enzymes are preferably encapsulated enzymes as previously described.

[0132] At this step, the counter-current saccharification (CCH) method with the help of encapsulated or infiltrated cellulase catalyst is considered to increase the hydrolysis efficiency of cellulose and hemicellulose and reduce the operation time.

[0133] Conventionally, enzymatic saccharification is performed in batch process with typical reaction times of about 3 to about 7 days. At the end of batch saccharification, enzyme activity remains, but leftover enzymes are usually discarded. To reduce the enzyme costs by reusing the leftover enzymes, the counter-current process was done.

[0134] For chemical processes, counter-current systems are generally more efficient than batch and offer advantages such as more efficient utilization of substrates, continuous processing that avoids loading and unloading idle times, and less product inhibition.

[0135] In counter-current saccharification (CCH) system, the biomass and liquid flow enter the system in opposite directions. The fresh biomass encounters product liquid at one end and digested biomass encounters fresh liquid at another end. The enzyme (especially [3-Glucosidase) addition point selected strategical to maximize enzyme utilization. The enzymes present in the product liquid are used by fresh active biomass atone end, thus reducing the impact of product inhibition. At the other end, digested biomass is washed with fresh liquid to recover spent enzymes and product sugars, thus improving process efficiency. The liquid product can potentially reach high sugar concentrations because it last contacted fresh highly reactive biomass.

[0136] The optimized operation is achieved by an efficient use of the enzyme, allowing a reduction in the enzyme loading of about 8 to about 20 times compared to the conventional mode.

[0137] As can be seen in and Figure 17, instead of using one reactor for hydrolysis, a continuous system of several successive reactors is used. From one side of this system 145 (the first reactor) the solids from the pretreatment step along with cellulase-at-MOF catalysts enter and from the other side the system 231 (the last reactor) the enzyme solution enters.

[0138] In this innovation, metal-organic frameworks operate in two stages. Once mixed with fresh biomass entering the system and once in the last container. MOFs mixed with biomass have the role of preventing the inhibitory effect of glucose and lignin with the enzyme and move along the entire path with biomass and continue saccharification even in high sugar concentrations. The final container MOFs are also used for the complete conversion of cellobiose into glucose, and since they are recoverable, they can significantly reduce enzyme consumption. In this innovation, for the first time, cellulase enzyme has been stabilized using MOF, which is a hydrophilic metal-organic framework. It has been shown that the enzymatic activity of this catalyst is reasonably comparable to the free enzyme, while this system is also reusable unlike the free enzyme.

[0139] In general, this invention provides a complete system for saccharification of lignocellulosic biomass. This system includes Several reactors that are placed next to each other in a row. First reactors form the counter-current saccharification (CCH) system and the last reactor 147 is related to Cellulase @MOF system. Freshly pre-treated biomass along with a small amount of Cellulase @MOF is entered into The penultimate reactor and in this reactor, it meets with a solution rich in sugar. As a result, their cellulose and hemicellulose compounds are hydrolyzed by soluble enzymes and enzymes stabilized in Cellulase @MOF and reducing sugars are produced. Then, the solid biomass along with Cellulase @MOF mixed with it is separated from the enzyme solution and enters Previous reactor and from there it moves along the system in a counter-current flow with the enzyme solution until it finally enters first reactor.

[0140] In first reactor, the biomass, where most of its cellulose and hemicellulosecontents have been converted into reducing sugars, is exposed to fresh enzyme solution. This fresh solution, with the help of Cellulase @MOF systems, which still relatively maintain their activity, saccharify the remaining cellulose and hemicellulose of the hydrolyzed biomass and produce reducing sugars.The solution of penultimate reactor also enters last reactor. Where the solution containing cellobiose and other monosaccharides is mixed with Cellulase @MOF catalysts and the remaining cellobiose is converted into glucose. In each existing biomass reactor, they are mixed with enzyme solution and catalysts of Cellulase @MOF at a temperature of 50 to 60 degrees for a certain time (1 to 2 days).

[0141] This innovation solves the problems in the existing saccharification systems. As mentioned, conventional batch systems consume large amounts of enzymes, and the counter-current method can solve this problem to a large extent. But in counter-current reactors, due to the inhibitory effect of sugars and lignin, the reaction time must be limited, and this reduces the saccharification efficiency. The use of Cellulase @MOF systems compensates for this limitation, because it reduces the inhibitory effect of sugar and lignin. Also, counter-current systems require the addition of fresh enzyme solutions and [3- Glucosidase supplements during the process. But the existence of Cellulase @MOF catalysts that move along the system along with the biomass solves this need and saves on enzyme consumption. In the last step, the final sugar solution enters a reactor containing Cellulase @MOF and the remaining cellulose and cellobiose are converted to sugar and the conversion percentage will increase.

[0142] In Figure 4, a fresh enzyme / buffer solution (FRESHENZ) goes to the SACC3 reactor and is mixed with BIO2OUT, the cellulose previously used for saccharification in SACC2. SF3 is the mixture of FRESHENZ and BIO2OUT entering the SACC3 reactor. It must be noted that because simulator has limitations for introducing feed streams to a reactor, a mixer (MIX3) was needed in the flowsheet design. However, it is unnecessary; both streams can enter SACC3 without initial mixing. Therefore, after the saccharification reaction occurs in the SACC3 tank, SP3, which is the product, exits the reactor; this stream contains the residues of the thrice used cellulosic content which is now wastes (BIO3OUT) and the produced sugar solution mixed with enzyme / buffer (SUG1 ENZY). The BIO3OUT is a waste with no sugar left to be produced and goes for disposal, SP3 goes through a separator (SEP3) to separate SUG1 ENZY and BIO3OUT from each other, then SUG1 ENZY goes to SACC2 for further usage. So, using a separator after each saccharification reactor is a must. Then, as previously mentioned, the SUG1 ENZY goes toSACC2 to mix with a once used cellulosic content from the SACC1 tank, which is BIO1 OUT.

[0143] This is the same as what has occurred and described for SACC3; therefore, for SACC2, The BIO1 OUT and SUG1 ENZY are mixed (because of the limitations of simulator, a mixer MIX2 had to be used) and enter the SACC2 tank as SF2, which is the feed stream for SACC2 (notably use of a mixer MIX2 is not a must in practice). After the saccharification process occurs in SACC2, SP2, the product stream exists the SACC2, which contains a more saturated sugar solution mixed with leftovers of enzyme / buffer solution (SUG2ENZY) and a partially used cellulose (because it has been used once in SACC1 ), which is going to be used in SACC3, called BIO2OUT. A separator (SEP2) is used to separate SUG2ENZY and BIO2OUT from each other. Therefore, the SUG2ENZY goes to SACC1 to mix with raw and fresh cellulose from hydrothermal processes.

[0144] This is the same as what has occurred and described for SACC3 and SACC2; therefore, for SACC1 , the feed stream for the SACC1 reactor is SF1 which contains fresh / raw cellulose from the pretreatment step (HEMICELL) and a partially saturated sugar solution mixed with twice used enzyme / buffer solution (SUG2ENZY). Due to the simulator limitations, mixer (MIX1 ) was used in the flowsheet, but as previously mentioned, it is not necessary in practice. After the saccharification step occurs, the product exits as SP1. SP1 contains the final concentrated sugar solution, which will be used in the fermentation step (FINALSUG), and once processed / used, cellulose (BIO1 OUT). A separator (SEP1 ) has to be used to separate FINALSUG and BIO1OUT from each other. Therefore, the FINALSUG stream will be used in the fermentation tank to produce alcohol, and BIO1 OUT will be used in SACC2.

[0145] In the first reactor, the inlet stream SF1 comprises fresh / raw cellulose from the pretreatment step (HEMICELL) and partially saturated sugar solution mixed with enzyme / buffer solution (SUG2ENZY). The outlet stream SP1 comprises the final concentrated sugar solution (FINALSUG) and once processed / used cellulose (BIO1 OUT).

[0146] In the second reactor the inlet stream SF2 comprises the once used cellulose (BIO1 OUT) and the once produced sugar solution mixed with enzyme / buffer solution (SUG1 ENZY). The outlet stream SP2 comprises the partially saturated sugar solution mixed with enzyme / buffer solution (SUG2ENZY) and a twice used cellulose (BIO2OUT).

[0147] Finally, In the fifth reactor, the inlet stream SF5 comprises the four times used cellulose (BIO4OUT) and fresh enzyme / buffer solution (FRESHENZY). The outletstream SP5 comprises the once produced sugar solution mixed with enzyme / buffer solution (SUG1 ENZY) and a five times used cellulose (BIO5OUT).

[0148] The five times used cellulose (BIO5OUT) goes for disposal and the final concentrated sugar solution (FINALSUG) is sent to the fermentation reactor.

[0149] The reactors have the same specification and characteristics and operate in the same operating conditions. The saccharification temperature is from about 35QC to about 50QC, preferably from about 40QC to about 45QC. The pressure applied is from about 0.5 atm (5x105Pa) to 2 atm (2x105Pa), preferably 1 atm (1 x105Pa).Step V - Fermentation Step

[0150] The fermentation step (step V) is performed using a fermenter. The raw material comprises a number of microorganisms such as yeast and bacteria. Commonly, Saccharomyces cerevisiae and Zymomonas mobilis are responsible for performing the fermentation. In the present invention, Saccharomyces cerevisiae is added to the fermenter tank.

[0151] One of the by-products of this process is carbon dioxide.

[0152] For the present invention, the first period of production would last around 2-3 days (batch process). After that time, the process starts a semicontinuous or continuous process, allowing a daily production of 2G bioethanol.

[0153] The fermentation process is operated during 3- 4 days in temperatures from about 30QC to about 40QC, preferably about 32QC to about 35QC. Like the saccharification process, the pressure applied is from about 0.5 atm (5x105Pa) to 1 atm (1 x105Pa), preferably about 0.7 atm (7x104Pa) to about 0.9 atm (9x104Pa).Step VI - Distillation Step

[0154] After the stream of diluted alcohol leaves the fermenter, it enters a continuous centrifuge. The centrifuge separates the diluted alcohol in two streams: fermentation broth stream and water / alcohol mixture stream. Then the alcohol mixture goes to a falling film distillation tower to be purified. A waste residue of water / alcohol / broth leaves the bottom of the tower, and from the top part of the column, the final product, 2G bioethanol, is produced by condensing the ethanol vapors. For the present invention, the distiller is a falling film evaporator (FFE) tower 154 coupled with a thermosiphon condenser 103.

[0155] The low concentration alcohol comprising ethanol enters the FFE 154 to increase the ethanol concentration to the azeotropic point (95.6%). For instance, hot steam with temperatures from about 70QC to about 90QC in the falling film tubes 156. Thenhot steam is used to heat the feed instead of using a boiler at the bottom of the column of falling film. The steam from the FFE then enters the thermosiphon cooling system 103.

[0156] In the process detailed in Figure 5 the feed enters the column via inlet (A) 155; when the feed is in the tower, a small plate hits it in the top part of the falling film ducts 156, which leads to a better distribution of the feed. Then the column is filled with hot steam via steam inlet (B) 106. The steam passes through the ducts 156, heating the feed inside the ducts and falling down the column. At the end of the falling film process, the hot steam loses its temperature due to heating the feed inside and exists the column using the outlets (D) 105.

[0157] The feed is then distilled due to the falling film transfers, which leads the concentrated slurry to exit at the bottom of the small ducts, the residue. The residue is a heavier and more concentrated form of the feed exits the tower from the bottom part of the column (E) 157, while the distillate moves through (F) for further separation then exits via upper outlet to the condenser.

[0158] As it is illustrated, section (F) is a simple flash tank 158, which operates to separate the liquid from vapor for better yields of production.

[0159] When the distillate enters the condenser 103, it goes through a series of coillike pipes 160, then condenses and exists via the bottom outlet of the condenser 163. The condenser is filled with a refrigerant, for instance, R134a, water, NH4OH or similar, the main source for cooling the ethanol vapor.

[0160] Figures 7A, 7B and 7C show that the thermosiphon rods (heat pipes) 160 are placed to create a natural refrigerant circulation as the system operates continuously. What happens is that when the ethanol vapor enters the condenser 103, it gives its heat to the refrigerant and condenses to liquid, the refrigerant which now is hot and in a lighter state exists via the upper section of the bottom and enters the upper chamber 102 where the fans 161 are located to cool down. When the refrigerant is cooled enough and becomes heavier, it exists in the upper chamber 102 and enters the bottom chamber 102 in the lower section.

[0161] The present thermosiphon 103 consists of tanks 102 containing the refrigerant connected by heat pipes 160. The pipe 160 containing the hot vapor (ethanol, etc.) enters the tank containing the refrigerant and heats the refrigerant liquid while passing through the tank 102. Heat is transferred by heat pipes 160 due to the difference in density to another tank 102 that has a fan 161 . The cooled liquid returns to the first tank 102 (heat transfer) due to the increase in density and is used to cool the tube containingthe hot steam.

[0162] Notably, the thermosiphons 103 are a passive cooling system that relies on gravity to circulate a refrigerant fluid rather than a capillary wick structure. The benefits of these systems are pacts, water usage, and long run time without utility.

[0163] When hot 2G bioethanol passes through the tube, the refrigerant absorbs heat and the 2G bioethanol cools down. The heated refrigerant enters the upper chamber 102 without the need for a pump due to the difference in density and is cooled by special fans 161 and returns to the main tank again due to the difference in density and gravity. The heated refrigerant enters the upper chamber 102 without the need for a pump due to the difference in density and is cooled by special fans 161 and returns to the main tank again due to the difference in density and gravity. Using a thermosiphon cooler 103 can cool ethanol vapor without the need for a pump and consuming extra electricity. The cooled 2G bioethanol then enters the chamber containing the powder molecular sieve 164.

[0164] Molecular sieves 164 are synthetic beads with small pores. The pores are large enough to allow water molecules to pass through but small enough to restrict the flow of ethanol into the beads. Molecular sieve 164 has been widely used because of its high adsorption capacity, strong thermal stability and other advantages. The water saturates the beads, while the dry ethanol passes through the system. Type 3A molecular sieves 164 are considered as the most effective type to dry ethanol. High temperatures and a pressure swing vaporize the water within the beads. The beads are re-used for further separation. This technique is a physical separation, meaning the azeotrope does not limit the ability to remove the water.

[0165] The present invention also teaches a system for the production of 2G bioethanol. The system comprises: an ultrasonic hydrothermal reactor 172 configured to convert the raw material into a heterogeneous mixture of cellulose, hemicellulose and lignin; a decanter / separator configured to receive the heterogeneous mixture of cellulose, hemicellulose and lignin from the ultrasonic hydrothermal reactor and separate the solid part from the solution; five or more saccharification counter-current reactors 146, each configured convert cellulose and hemicellulose to sugars via metal-organic framework cellulase complex (cellulase-at-MOF), one mixer before each reactor for mixing at least the cellulose / hemicellulose and the cellulase-at-MOF, and aseparator after each reactor for separating one or more between the non- converted cellulose / hemicellulose, cellulase-at-MOF and the glucose; a fermenter configured to receive the glucose separated from the mixer located after the first reactor and convert the glucose into diluted alcohol and slurry; a decanter / separator 230 configured to receive and separate the diluted ethanol and slurry; a falling film distiller 154 with an inlet for the diluted ethanol 155, a top outlet 105 and a bottom outlet 157, wherein the bottom outlet transports the residues and the top outlet transports a steam of 2G bioethanol; a thermosiphon 103 configured to convert the steam of 2G bioethanol into liquid 2G bioethanol.

[0166] Different embodiments of the invention can comprise combinations of machines.

[0167] Prior to the UBH reactor 172, elements can be selected from, but not limited to:-a shredder to convert the flow of raw material into shredded straw; and / or-a dryer configured to dry the straw, wherein the dryer can be a rotational dryer, a vertical dryer, fluidized bed, infrared dryer, rolling beds or it can be dried in the sun; and / or-storage silos to increase the shelf life; and / or-a mixer configured to mix the inlet of dry straw flow with an inlet of water flow.

[0168] Different decanters or separators may be used. In the present invention the centrifugal separators due to their efficiency and performance.

[0169] In the present invention, the UBH reactor is used for the pretreatment of biomass in processes for producing biofuel such as 2G bioethanol, biogas and biodiesel.EXAMPLES

[0170] The present invention refers to a UBH reactor comprising reactor body 172, ultrasonic probes 177, curved baffles 180, limped heating coil 181 , shell (jacket), lid 176, and agitation system 182.

[0171] The reactor body 172 comprises cylinder and torispherical parts, a product outlet 174, feed inlets 66, an ultrasonic flanged lid, and a shaft 175 to hold the presented baffles 180. The reactor body 172 and lid 176 are airtight flanged sealed.

[0172] The reactor body 172 is a 5000-liter conventional cylindrical chemical reactor with a torispherical head and bottom.

[0173] At the top of the reactor cylinder, a flange 176 is considered for sealing the body and lid together.

[0174] The reactor comprises an outlet 174 for discharging the treated straw is a conventional cylinder tube with a flanged head.

[0175] The reactor has a cylindrical shaft 175 that is a foundation for holding the curved baffles 180. The shaft 175 has a space inside that lets the agitator shaft 175 spin freely.

[0176] The lid has two feed inlets consisting of 2 identical ports. Sixteen (16) bolts are considered for the flange sealing the lid and reactor together. Each feed inlet has a flange with 12 bolts.

[0177] The three ultrasonic holders 177 are equally distanced from the center point are end comprise equal distances from each other; these holders 177 come with flanges so that after the ultrasonication, the ports are completely sealed. Each holder has a flange with eight bolts.

[0178] The reactor also comprised a thermometer holder with the exact dimensions and characteristics as the ultrasonic holders, placed parallel to one of the ultrasonic holders.

[0179] The reactor also comprises 2 pairs of air inlet and outputs for pressure regulations. Each pair has flanges with the same characteristics as the other ports with eight bolts.

[0180] The baffles 180 of the reactor are curved with circular holes on each of them. From the top view, the ultrasonic probes 123 are placed precisely in the middle between a pair of baffles 180. All baffles 180 are equally distanced, with a thickness of 0.5 cm and a radius of 45cm. The baffles 180 also have a distance of 15cm from the reactor body 172. Each baffle 180 has 7 and 21 holes in horizontal and vertical order, respectively.

[0181] For heating regulations, a conical spring tube heating coil 181 is used. The coils 181 are wrapped around the reactor in 13 revolutions with an inlet and outlet 183 for steam. The steam ports 183 have the same flange characteristics as the ultrasonic holder flanges.

[0182] The agitation system comprises a four-blade conventional diagonal fin 182 used for agitation.

[0183] The shell is used as a heat jacket is considered to coat the reactor. It has anidentical inlet and outlet for oil. It also has two foundations to lift and hold the reactor entirely. It is not necessary to have these ports. Also, legs can be added to the shell so that the reactor is standing.TESTS1.1 Straw content1.1.1 Proximate general features

[0184] The biomass used when performing the following tests was a rice straw sample.

[0185] A proximate analysis provides an insight into the moisture, volatile matter and ash content of a sample which eventually estimates the overall fixed carbon of a particular sample. As a result, the rice straw used in the present work was analyzed 3 times.

[0186] The moisture content was found to be 15.6% by weight. In general, any carbonaceous material which has got greater percentage of moisture content produces hindrance towards combustibility of the substance.

[0187] The ash content in the sample was observed to be 13.4%.

[0188] Similarly, presence of higher percentage of volatile matter content suggests versatility of active sites present on the substance. Volatile matter content was found to be 62.8%. Therefore, a carbon content of 8.3% ensures an appreciable carbon network which might help in surviving of the sample after delignification. Table 2 comprises the percentage of the contents in each analysis.Table 2 - Straw content analysis (percentage by weight [w / w%])1 .1 .2 Lignin content

[0189] The UV-visible (UV-vis) spectra related to the amount of acid soluble lignin, shows the effectiveness of the selected pretreatment method.

[0190] The data related to the determination of lignin content and the effectiveness of the pretreatment method are mentioned in the table below.Table 3 - Absorbance results for different methods* us is an abbreviation for ultrasound**80, 100, and 120 are temperatures in Celsius Degrees

[0191] As can be seen in Figures 9 and 10 and table 3, absorbance has decreased in proportion to the presence of baffles and ultrasonic waves. This means that delignification has increased what is corroborate by a 14.05% delignification when the new baffle is used in comparison to 9.64% delignification obtained with conventional baffle.1 .2. Baffle effect on Solubility

[0192] Table 4 shows the effectiveness of the presence of the baffle as described in the present invention compared to the conventional baffle and the absence of the baffle.Table 4 - Baffle tests first second third Mean parameter time (s) time (s) time (s) (s)

[0193] For this purpose, potassium permanganate drops are added to the water in the absence of baffle, the presence of conventional baffle and the presence of new baffle. The new baffle is tested in two conditions: the first is when the curvature of the blades is the same as the direction of the solution circulation, and the second is when they are in the opposite direction.

[0194] The aforementioned data shows a significant increase in reactor solubility when the baffles are present.1 .3. Structural changes1.3.1. Fourier-transform infrared spectroscopy (FTIR)

[0195] The FTIR technique was performed to investigate the chemical and structural changes of the straw due to pretreatment. In the Fig. 11 , the spectrum of untreated straw can be seen.

[0196] The assignment of FTIR peaks corresponding to the functional groups of lignocellulosic components is listed in Table 5.Table 5 - Wavelengths

[0197] As it can be seen, the FTIR spectra between the untreated and treated samples showed clear differences in terms of intensity and shape.

[0198] The raw rice straw showed the peak of C=C stretching of aromatic ring of lignin at 1600-1610 cm-1, C=C aromatic skeletal vibration stretching of the benzene ring in lignin at 1495-1520 crrr1, and C-O-C stretching of primary alcohol in cellulose and hemicelluloses at 1045-1055 cm-1. This spectrum is used to check the baffle effect as wellas temperature and ultrasonic. The first peak observed at 780 cm-1corresponds to C-H group present in lignin and for out of plane vibration of C-H group in lignin.

[0199] As it can be seen in Figure 12, all functional groups in the raw rice straw were identified in the pretreated rice straw samples in the presence of baffle according to the FTIR spectra.

[0200] However, the lower intensity of these peaks was observed after pretreatment, suggesting solubilization of the lignin and partial hemicellulose fractions. The characteristic lignin peaks at 1320 (C-0 of syringyl) and 1268 (C-0 of guaiacyl ring) car1have significantly reduced.

[0201] It is noticeable in Figure 12 that the peak intensity in the presence of the baffle shows a greater decrease than in the absence of the baffle. In addition to that, the baffle designed by our researchers shows the lowest peak intensity.

[0202] Furthermore, the higher intensity of C-H deformation of glucose ring in cellulose and hemicellulose at 885-890 cm-1of the pretreated samples compared to that of the raw material also suggested the change in cellulose structure after the pretreatment step. The broadband at 3400-3200 and the signal at 2910 car1have been assigned as the O-H stretching of hydrogen bonds and C-H bonds, respectively. These bands are sensitive to characteristic features of cellulose. The reduction in transmission peak of O-H vibration in pretreated rice straw can be caused by the decrease in the percentage of lignin, which increases the interaction between radiation and cellulose.

[0203] One of the effects of the pretreatment is the removal of wax from the straw. The CH2- stretching bands at approximately 2850 and 2920 cm-1are reduced for the pretreated straw sample, signifying a reduction in the amount of the aliphatic fractions of waxes. It can be seen that the carbonyl band at 1735 cm1, which has been ascribed to hemicelluloses is reduced for the pretreated straw. This is expected as the pretreatment is known to remove a large portion of the hemicelluloses. In other words, the signal around 1720 cm-1corresponding to the C=O functional group is a characteristic peak of ester linked acetyl, feruloyl, and p-coumaroyl groups between hemicelluloses and lignin. The near absence of this peak indicates removal of lignin through ester bond cleavage by the pretreatment.

[0204] These results are consistent with the chemical composition analysis and confirm the reduction in lignin and the increase in cellulose contents after pretreatment showing that degradation of lignin is done very well and the straw structure is suitable for the hydrolysis step.

[0205] In Figure 11, the signal at 900 crrr1is also attributed to ?-1 ,4-glycosidic linkages, revealing the typical structure of cellulose. The band at 1735 crrr1represents the characteristic peaks of the hemicellulose-lignin complex. The intensity was disappeared in pretreated rice straw, indicating that the alkaline pretreatment could not only hydrolyse the lignin fraction but also extract some hemicellulose. The peaks at 1510 crrr1(guaiacyl ring from lignin) almost disappeared in NaOH-pretreated straw, which indicated the occurrence of extensive delignification. The saponification reactions between NaOH and intermolecular ester bonds in lignin were the key factors causing lignocellulosic structure changes after NaOH pretreatment, which contributes to lignin removal and cellulose release, while this spectral band at 1510 crrr1could be seen in untreated straw.

[0206] The most significant structural changes were appreciated for the spectra from (120+ultra), while the least modifications were observed in (100). The band at 3330 crrr1representing OH stretching is displaced to higher intensities in pretreated samples, indicating an increase in the free hydroxyl groups and reduced intermolecular hydrogen bonding. Absorption bands at 1430 and 897 cm-1represent crystalline cellulose I and amorphous cellulose II, respectively. After pretreatment, the bands at 1430 cm-1were reduced, while those at 897 cm-1became more intense, which means that pretreatment reduces cellulose crystallinity.

[0207] Absorption bands at 2852, 2925, and 2935 cm-1are characteristic of lignin structure, corresponding to symmetric and asymmetric CH stretching of CH3, CH2, and CH, softened after pretreatment, probably due to lignin depolymerization. The band at 1600 crrr1(stretching of aromatic benzene ring in lignin) was practically disappeared in pretreated biomass, indicating partial removal of lignin. Major changes in functional groups of rice straw components (hemicellulose, cellulose, and lignin) were observed. Strong wide band between 3100 and 3500 crrr1has assigned for O-H stretching vibration of lignin. The infrared spectrum at 3409 crrr1in raw rice straw is caused by the presence of phenolic and alcoholic hydroxyl group.

[0208] According to FTIR data, it is possible to understand the high importance of ultrasonic in increasing the efficiency of delignification.1.3.2. Scanning Electron Microscopy (SEM)

[0209] The microstructure and morphology of the raw and pretreated biomass was determined by scanning electron microscope. Scanning electron micrographs are shown for raw rice straw (RS), unbaffled and baffled pretreatment in 15 min in Figure 14 and Figure 15 which indicate the changes in the surface morphology of the rice straw.

[0210] The surface roughness was enhanced after pretreatment which was higher for presence of baffle as compared to absence of baffle. Hence, baffle was more effective in enhancing the surface area of rice straw which is favourable for enzymatic and microbial attack leading biofuel production. This increment in surface area of rice straw can be attributed to lignin and hemicellulose degradation which increases the amorphous nature of cellulose.

[0211] Scanning electron microscope was used to study the structural changes of rice straw resulting from the pretreatment process.

[0212] As presented in Figure 14, the untreated rice straw showed a rigid and highly ordered structure. Also, there are present fine spots on the surface called as papillae and silicaceous structures called as phytoliths, present in the form of large lumps. After the pretreatment, cellulose fibers were clearly exposed to the surface with the dumbbell silica body next to it indicating destruction of microfibrils and cell structures such as cuticle, silica layers and silicaceous bodies together with lignin.

[0213] The absence of these surface moieties along with clean cellulose fibers helps to increase the cellulose accessibility to the enzymes, resulting in good digestibility and saccharification performance. Since a large quantity of hemicellulose and lignin content was removed after pretreatment, it became of interest to examine the morphological changes of the rice straw by scanning electron microscopy.

[0214] The longitudinal section of rice straw before and after pretreatment is shown in Figures 14, 15 and 16. As we observed, significant morphological changes indeed occurred. The untreated rice straw exhibited rigid and highly ordered fibrils, while the fibers of pretreated samples were distorted. Moreover, the microfibrils were separated from the initial connected structure and fully exposed, thus increasing the external surface area and the porosity of the rice straw.

[0215] It can be seen that the untreated rice straw showed intact physical structure with no cracks and cavities and covered with an intact wax-coated surface.

[0216] Overall, pretreatment in the presence of NaOH and in different temperatures resulted in structural changes in the biomass surface due to efficient removals of the cuticle wax and silica layers. The use of the UBH reactor led to formation of higher porous structure and increased surface area of the biomass. Their modified structure allowed increasing accessibility of the enzymes to the inner cellulose microfibers in the substrate.2. Hydrolysis / saccharification step2.1. Saccharification Method

[0217] In the laboratory, it is convenient and practical to use multiple centrifuge bottles to achieve counter-current movement of solids and liquids. The counter-current test was designed as a 5-bottle (5-step) process. A 30% ratio of rice straw substrate to citrate buffer was placed in each container, and then 0.002 grams of enzyme per gram of straw was added to the containers.

[0218] Daily sampling (every 24 hours) was done from the Fifth container. During this interval, the sugar solution and the solid substrate move in the opposite direction inside the containers, and the sugar solution leaves the third container. Finally, on the last day, all the solutions of all Five containers are mixed together.

[0219] Along with this reaction, simple one-pot hydrolysis with the same enzyme concentration and substrate weight with the counter-current method was also used as a control reaction.

[0220] The results were analysed by measuring the amount of sugar produced through HPLC analysis.

[0221] Based on the HPLC chromatogram results, the optimal performance of enzymatic hydrolysis is determined by the efficient use of the enzyme. The counter-current saccharification method allows the enzyme loading to be reduced several times compared to the usual state. Table 6 shows the amount of sugar produced during each of the two methods of simple hydrolysis and counter-current hydrolysis.Table 6 - Sugar content after hydrolysis

[0222] The results of the experiments were favourable because once the volume and the number of counter-current bottles are increased, the difference between batch and counter-current hydrolysis is wider.

[0223] CCH shows its high efficiency when more steps are used in the process.

[0224] CCH system maximizes conversion, minimizes enzyme requirements, and reduces enzyme loading requirements while maintaining high conversions and product concentrations.2.2. Biomimetic mineralization method and Catalyst activity assay

[0225] In the Biomimetic mineralization method, organic solvents and high and low temperatures are avoided so as not to damage the enzyme.

[0226] In the present invention, enzyme immobilization catalysts have been prepared in an encapsulated form (Cellulase-at-MOF) and by the biomimetic method of mineralization in a one-pot process.

[0227] The method of synthesis of catalysts is carried out through the following general route: a) preparing an aqueous solution of metal salt; along with 2mg c ellulase / mL citrate buffer; b) preparing an aqueous solution of organic ligand c) adding solution (a) slowly and dropwise to solution (b) which is being stirred at room temperature; d) centrifuging and washing the structures after about 6 to about 12 hours, e) Finally, drying and storing the structures.In the present invention, the structures are dried by a freeze-dryer and stores in a refrigerator at a temperature of about 0QC to about 6QC, preferably about 2QC to about 5QC, most preferably about 4QC. f) Enzyme activity of the catalysts has been investigated with the help of DNS reagent and by studying the resulting UV spectrum at 540 nm.

[0228] The synthesis yield of the MAF-7 and Cellulase-at-MAF-7 Prepared through biomimetic mineralization is shown in Table 7.Table 7 - catalyst synthesis

[0229] The results of UV absorption at a wavelength of 540 nm are shown in Table 8. Catalyst refers to Enzyme-at-MOF samples, catalyst control refers to MOFs without enzymes and Synthesis solution is the solution obtained from washing Enzyme-at-MOF catalysts, which contains the remaining and un-stabilized enzyme in the structures.Table 8 - Catalyst UV absorption

[0230] These results indicate that Cellulase-at-MAF-7 is a very suitable sample for enzyme stabilization.

[0231] Employing MOF as a coating to protect the enzymes under harsh conditions provide a new promising tool for the further exploitation of bio-composites for industrial applications.2.3 Scanning Electron Microscope of MOF catalyst

[0232] Scanning electron microscope images of MAF-7 and Cellulase@MAF-7 samples are shown in Figures 18 and 19, respectively. Although SEM analysis shows that the structures are not fully dried and MAF-7 particles are stuck together, but observing the existence of MAF-7 structures is acceptable considering that these structures are prepared in water environment without heat and pressure. In the images related to Cellulase@MAF- 7, the placement of enzymes on MAF-7 structures can also be seen well.2.4 X-ray diffraction of MOF catalyst

[0233] XRD spectrum images of MAF-7 and Cellulase@MAF-7 samples are shown in Figures 20 and 21. In the XRD spectrum of MAF-7, the characteristic 29 angles corresponding to these organometallic frameworks are clearly visible (angles 11 , 13, 16, 18, 25 and 30). But in cellulase@MAF-7, due to the presence of enzyme in the structure, despite the presence of peaks related to MAF-7 angles, the overall structure has little crystallinity and has become amorphous. This can indicate the placement of the enzyme inside the structures.

[0234] In view of the above, it is clear that the UBH reactor as proposed has an important influence in the pretreatment of biomass, destroying the recalcitrant structure of lignocellulose thus accelerating the break of lignin without the need of expensive or unsafe additives and / or acidic environment, with the use of the UBH reactor in the pretreatment step in addition to the step for the counter-current hydrolysis using the MOF-infiltrated or encapsulated enzymes, which can be reutilized during the process, not only acceleratesthe process but also provide a higher amount of sugar for the fermentation broth, reducing the discharge of residues. The falling films coupled with the thermosiphon also reduces the energy cost.

[0235] The UBH reactor of the present invention provided 14.05% of delignification compared to the 9. 64% when using a conventional baffle (more that 45% increase of the solubility). Thus, the effectiveness of the presented baffle solubility (32%) is more than 7% higher than for the conventional baffle. As a result, the efficiency of the pretreatment is more than 51%.

[0236] In addition to that, in the hydrolysis / saccharification step it was shown that using CCH system maximizes conversion, minimizes enzyme requirements, and reduces enzyme loading requirements while maintaining high conversions and product concentrations. The use of cellulase-at-MOF during this stage also increased the process efficiency and the enzyme consumption.

[0237] With the final stage being the distillation, the use of the falling films coupled with the thermosiphon reduced the process time, the cost and the energy consumption by removing the condenser.

[0238] Overall, the production of second-generation bioethanol as proposed not only adds a cheaper and faster possibility to reduce the competition between biofuels and food, but also alleviates the energy problem, and at the same time alleviates the current agricultural waste pollution.

[0239] The description of the different illustrative modalities was presented for purposes of illustration and description, and should not be exhaustive or limited to the modalities as described. Many modifications and variations will become apparent to those skilled in the art. Additionally, different illustrative embodiments may provide different features compared to other illustrative embodiments. The selected embodiment or embodiments are chosen and described in order to better explain the principles of the embodiments, the practical application, and to allow others skilled in the art to understand the description for the various embodiments with various modifications that are suitable for the particular use contemplated.List of references:1 - Mariano, A. P. B., Unpaprom, Y., Ponnusamy, V. K., & Ramaraj, R. (2021 ). Bioethanol production from coconut pulp residue using hydrothermal and postalkaline pretreatment. International Journal of Energy Research, 45(6), 8140-81502- Cirujano, F. G. (2019). Engineered MOFs and enzymes for the synthesis of active pharmaceutical ingredients. ChemCatChem, 11(23), 5671 -5685.3- Fang, FL, Dhakshinamoorthy, A., Li, Y., & Garcia, H. (2020). Metal organic frameworks for biomass conversion. Chemical Society Reviews, 49(11 ), 3638-3687.4- Battisti, FL, Machado, FL A., & Marangoni, C. (2021 ). Comparative Study of the Separation of a Binary Mixture Ethanol-Water and 2G-Ethanol in a Pilot-Scale Thermosiphon -Assisted Falling Film Distillation Unit. Chemical Engineering Transactions, 86, 1099-1104.5- Cao, C., Xie, L., Xu, S., Liu, Q., & Du, Y. (2020). Improved Heat Transfer Performance of Falling Film Evaporator for Desalination Industry by Balanced Liquid Distribution. Industrial & Engineering Chemistry Research, 59(46), 20492-20503.LIST OF NUMERALS66 Inlets for untreated material, see figur 5 and 673 Agitator motor102 Refrigerant Tank103 Thermosiphon body105 Steam outlet106 Steam inlet123 Ultrasonic probes, see figure 2 and 3145 Counter-current feed inlet146 Second counter-current reactor147 Last counter-current reactor148 Counter-current outlet154 FFE155 FFE feed inlet156 FFE ducts157 Falling film residue outlet158 Seprator Tank159 Thermosiphon inlet160 Heat pipes161 Fan163 Thermosiphon outlet164 Molecular sieve172 Reactor body,, see figure 1 , 2 and 3174 Outlet for reactor products, see figure 1 and 2175 Agitator shaft, see figure 2 and 3176 Reactor lid177 Ultrasonic holders, see figure 3178 Thermometer180 Curved baffles181 Heating / cooling coils inside reactor, see figure 2 and 3182 Blades inside the reactor, see figur 2 and 3183 Coils oil inlet / outlet230 Centrifuge231 Counter-current Enzyme inlet

Claims

CLAIMS1 . A process for producing 2G bioethanol comprising the steps of: i. obtaining the raw material; ii. physically pretreating the raw material; iii. hydrothermally pretreating the material that leaves step ii, forming a mix of lignin, cellulose and hemicellulose, wherein the hydrothermal pretreatment comprises converting the material in an ultrasonic baffled hydrothermal (UBH) reactor (62); iv. converting the cellulose and hemicellulose into glucose and xylose in the presence of an enzyme; v. fermenting the sugars into a diluted alcohol; vi. distilling the alcohol; and vii. obtaining the 2G bioethanol product.

2. The process of claim 1 , wherein step iii further comprises: a. shredding the raw material; b. drying the shredded raw material to produce a dry straw; and c. mixing the dry straw with water.

3. The process of claim 1 , wherein step iii further comprises: separating the cellulose / hemicellulose and wet lignin; and dehumidifying the wet lignin.

4. The process of claim 1 , wherein NaOH is added to the reactor of step iii.

5. The process of claim 1 , wherein step iv is performed in three or more saccharification counter-current (CCH) reactors, each configured to covert cellulose / hemicellulose to sugars via metal-organic framework cellulase complex (cellulase-at-MOF), further wherein the cellulase in at least one of: an infiltrated cellulase and encapsulated cellulase, and wherein the MOF is selected from the group comprising ZIF-7 (Zn), MOF-199 and MAF-7 (Zn).

6. The process of claim 1 , wherein step v is operated at temperature from 30QC to 45QC, and pressure from 0.5 atm (5x10A5 Pa) to 1 atm (1x10A5 Pa).

7. The process of claim 1 , wherein step vi comprises distilling the diluted ethanol at temperatures from about 70QC to about 90QC in a falling film evaporator.

8. The process of claim 1 , wherein the distillation further comprises using a thermosiphon to convert the gaseous bioethanol into liquid bioethanol.

9. A system for producing bioethanol comprising: a. an ultrasonic baffled hydrothermal (UBH) reactor (62) configured to convert the raw material into a wet flow of cellulose / hemicellulose and lignin as defined in claim 1 ; b. a decanter / separator configured to receive the wet flow of cellulose / hemicellulose and lignin from the ultrasonic hydrothermal reactor and separate the cellulose / hemicellulose from the wet lignin; c. five or more saccharification counter-current (CCH) reactors, each configured convert cellulose / hemicellulose to sugars via metal-organic framework cellulase complex (cellulase-at-MOF), one reactor at the end where only the final sugar solution and Cellulase @MOF are mixed, one mixer before each reactor for mixing at least the cellulose / hemicellulose and the cellulase-at MOF and free enzyme, and a separator after each reactor for separating one or more between the non-converted cellulose / hemicellulose, cellulase-at-MOF and the glucose solution; d. a fermenter configured to receive the glucose separated from the mixer located after the first reactor and convert the glucose into diluted alcohol and slurry; e. a decanter / separator configured to receive the diluted alcohol and separate the diluted alcohol into low bioalcohol and slurry; f. a falling film distiller with an inlet for the low bioalcohol, a top outlet and a bottom outlet, wherein the bottom outlet transports the residues and the top outlet transports a gaseous bioethanol; g. a thermosiphon configured to convert the gaseous bioethanol into liquid bioethanol.

10. An ultrasonic baffled hydrothermal (UBH) reactor (62) for the pretreatment of biomass comprising: i) a reactor body (172) coupled to a flanged-type lid, ii) wherein the flanged-type lid (176) comprises a plurality of inlets for the attachment of: an external heating / cooling inlet (183); a shaft aligned with the center of the flanged-type lid (175); and a plurality of ultrasonic probes (123), iii) wherein the reactor body (172) comprises: iii) a. an inlet (66) for the untreated material; iii) b. a bottom part with an outlet (174) for the reactor product; iii) c. a plurality of heating / cooling coils (181 ) inside the reactor body; iii) d. an air pressure inlet / outlet placed on the top external side of the reactor body; iii) e. an agitator shaft (175) inside the reactor body, the agitator shaft connected to a motor (73) and comprising: iii) e.i) an agitation system (182) at the bottom of the agitator shaft (175); iii) e.ii) curved baffles (180) above the agitation system (182); iii) e.iii) wherein the curved baffles (180) are configured to prevent the swirling / vortex of the materials in the reactor and increase the mixing rate; and iv) a shell comprising a heat jacket (181 ) with an identical inlet and outlet for oil, wherein the shell further comprises at least two foundation or legs to lift and hold the reactor.

11. The UBH reactor of claim 10, wherein the UBH reactor comprises baffles (180) in a range of 3 to 5 with each baffle (180) having holes in a range of 15 to 25, wherein the curved baffles (180), configured to prevent the swirling / vortex of the materials in the reactor and increase the mixing rate, are equally distanced and each of the curved baffles (180) comprise at least one of: circular and oval holes in a range of 5 to 10.

12. The UBH reactor of claim 10, further comprises equally distanced ultrasonic holders (177) and the number of ultrasonic holders (177) is proportional to the number of baffles (180), such that the number of ultrasonic holders (177) is in a range of 2 to 5; wherein each ultrasonic holder (177) comprises at least one flange with 8 to 16 equidistant bolts, further wherein the flanges of the feed inlet comprises 12 bolts andthe flange of the lid comprises 16 bolts; and wherein the plurality of heating / cooling coils (181 ) are wrapped around the reactor in 5 to 20 revolutions with an inlet and an outlet (183) for steam.

13. The UBH reactor of claim 10, wherein the agitation system further comprises a fin in a range of 2 to 6.

14. The UBH reactor of claim 10, wherein the temperature in the UBH reactor is in a range of 120QC to 150QC.

15. The UBH reactor of claim 10, wherein the pressure in the UBH reactor is in a range of 7 atm (7.1 x105 Pa) to 13.6 atm (1 ,27x10A7 Pa).

16. A thermosiphon cooling system for condensing the distilled ethanol comprising:The body of the device with the input and output sections, wherein the device body comprises: a. an inlet for the distilled ethanol vapor (159); b. a twisted pipe to transfer ethanol from the inlet to the outlet (160); c. refrigerant liquid (102); d. an outlet section for ethanol cooled by the system (163); e. an outlet pipe from the body to the cooling part to transfer the refrigerant (160); f. the cooling part includes a fan and heat pipes (102); g. an inlet pipe from the cooling part to the body to transfer the refrigerant (160);17. The thermosiphon cooling system of claim 16, to cool ethanol vapor and turn it into liquid.

18. Several Counter-current Hydrolysis (CCH) reactors (139) for the saccharification of pretreated biomass comprising: i) five or more reactors which are placed together in a sequence (141 ) ii) reactors body coupled to a flanged-type lid (145), iii) wherein the flanged-type lid comprises a plurality of inlets for the attachment of: an external heating / cooling inlet; and a shaft aligned with the center of the flanged- type lid;iv) wherein the reactors body comprises: iv) a. an inlet for the input feed material (146); iv) b. a torispherical bottom part with an outlet for the reactor product; iv) c. a plurality of heating / cooling coils inside the reactor body; iv) d. an air pressure inlet / outlet placed on the top external side of the reactor body; iv) e. an agitator shaft inside the reactor body, the agitator shaft connected to a motor and comprising: iv) e.i) an agitation system at the bottom of the agitator shaft; iv) e.ii) curved baffles above the agitation system; iv) e.iii) wherein the curved baffles are configured to prevent the swirling / vortex of the materials in the reactor and increase the mixing rate; and v) a shell comprising a heat jacket with an identical inlet and outlet for oil, wherein the shell further comprises at least two foundation or legs to lift and hold the reactor.

19. The CCH reactors of claim 18, wherein the UBH reactor comprises baffles, wherein the baffles are curved with circular holes on each of them. All baffles are equally distanced, with a thickness of 1 cm, width of 10cm and a height of 140.37cm. The baffles also have a distance of 2.5cm from the reactor body. 0.75-inch bolts were used to connect baffle pieces.

20. The CCH reactors of claim 18, further comprises a conical spring tube heating coil is considered with an inner diameter of 3cm and a thickness of 0.5cm. The distance between coils is 10 cm. The coils are wrapped around the reactor in 14 revolutions with an inlet and outlet for steam. The steam ports which are identical have the same flange characteristics.

21. The CCH reactors of claim 18, wherein the agitation system is a pair of four-blade conventional diagonal fin and anchor end. The shaft has a diameter of up to 10cm; the blades have 42.5cm in length, 10 cm in height, and 2 cm in thickness. The agitator is 5 cm distanced from the baffles. Each fin is distanced 50 cm from each other and for each fin base shaft has 12 cm diameter and 10 cm heights.

22. The CCH reactors of claim 18, wherein the temperature in the reactors is in a range of 45QC to 55QC.

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