BIOMASS CONVERSION

Abstract

Processes and reactor systems for biomass conversion are described. A continuous process for the conversion of carbo-hydrate-containing feed material into furanic compounds comprises a reaction step comprising subjecting said feed material to reaction conditions in a reaction medium comprising two immiscible liquid phases, including a reactive phase and an extractive phase, and a Brnsted acid as catalyst, wherein the reaction medium comprises a solid component comprising at least a part of a carbohydrate-containing fraction of said feed material.

Claims

1. A continuous process for the conversion of carbohydrate-containing feed material into furanic compounds, the process comprising a reaction step comprising subjecting said feed material to reaction conditions for said conversion in a reaction medium comprising a reactive liquid phase and an extractive liquid phase, wherein said liquid phases are immiscible with each other, and a Brnsted acid as catalyst, wherein the reaction medium comprises a solid component comprising at least a part of a carbohydrate-containing fraction of said feed material.

2. A process according to claim 1, wherein said Brnsted acid catalyst is a homogenous acid catalyst, wherein said reactor is a pulsed column reactor and wherein the reaction medium has a reciprocating forward and backward flow during said reaction step.

3. A process according to claim 2, wherein said feed material comprises a polysaccharide, wherein said reaction conditions cause the opening of the solid component, hydrolysis of polysaccharides to yield monosaccharides, and dehydration of said monosaccharides in a single reaction medium, wherein the reaction condition comprise a temperature of at least 150 C. and a pH of 2 or less, and the reaction conditions are applied to said polysaccharide in a reactor, wherein said at least two immiscible liquid phases have interfacial contact in said reactor and are in co-current flow or counter-current flow, and wherein particles comprising said polysaccharide are dispersed in at least one of said liquid phases of said reaction medium in said reactor and flow from an inlet towards an outlet of said reactor.

4. A process according to claim 3, wherein the frequency of the oscillations of the flow between forward and backward flow is 0.1 to 1.0 Hz.

5. A process according to claim 4, wherein the reactive phase is an aqueous phase and the extractive phase is an apolar organic phase, and wherein the volume ratio between the aqueous phase and the apolar organic phase, is 4:1 to 1:4.

6. A process according to claim 1, wherein the feed material is heterogeneous feed material.

7. A process according to claim 6, wherein said feed material comprises one or more selected from the group consisting of a sieve fraction from sewage treatment comprising cellulose fibres, a fraction of spoiled absorbent sanitary articles comprising cellulose fibres, and a fraction of manure comprising cellulose fibres, and wherein the reaction medium comprises cellulose fibres.

8. A process according to claim 1, wherein said process comprises one or more pre-treatment steps of said feed material upstream of said reaction step, wherein said pre-treatment steps provide for balancing of heterogeneities of the feed materials.

9. A process according to claim 1, wherein said extractive phase is an organic phase comprising an alkoxyphenol.

10. A process according to claim 1, wherein the amount of salts provided into the reactor other than originating from the feed material is maximized to an amount corresponding to less than 1.0 M added cations in total in said reactive phase.

11. A process according to claim 1, wherein the process comprises, downstream of the reaction step wherein furanic compounds are formed, one or more downstream processing steps comprising a step wherein the formed furanic compounds are subjected to one or more chemical reactions.

12. A process according to claim 11 wherein said chemical reaction is selected from the group consisting of oxidation, reduction, hydrogenation, esterification, amidation, and a condensation reaction.

13. A process according to claim 11, wherein said process comprises oxidation and esterification of 5-(hydroxymethyl)-2-furaldehyde and/or furfural into a dialkyl ester of 2,5-furandicarboxylic acid, and distillation of said ester.

14. A process according to claim 12, wherein said process comprises reacting furfural and/or 5-(hydroxymethyl)-2-furaldehyde with a hydrazine and/or hydroxylamine downstream of said reaction step.

15. A process according to claim 14, wherein said hydrazine and/or hydroxylamine is bound to a solid support, and wherein the process comprises removing said solid support from a liquid medium by solid/liquid separation together with furanic compounds bound to said solid support through a formed hydrazone and/or oxime link.

16. A process according to claim 14, wherein: said reactor is a pulsed column reactor and the reaction medium has a reciprocating forward and backward flow during said reaction step, a liquid stream comprising the formed furanic compounds and at least part of the organic extractive liquid phase is supplied from an outlet of said pulsed column reactor to an inlet of a downstream processing unit, at least the hydrazine and/or hydroxylamine are added into said liquid stream in said downstream processing unit, and the flow of the liquid stream is converted into forward only flow between said pulsed column reactor and the inlet of said unit.

17. A continuous process for the conversion of carbohydrate-containing feed material into furanic compounds, the process comprising: a reaction step in a reactor comprising subjecting said feed material to reaction conditions for said conversion in a reaction medium comprising two immiscible liquid phases, including a reactive phase and an organic extractive phase, and a Brnsted acid as catalyst, wherein the reaction medium comprises a solid component comprising at least a part of a carbohydrate-containing fraction of said feed material; and a telescoping step comprises reacting furfural and/or 5-(hydroxymethyl)-2-furaldehyde in at least part of said organic extractive phase with a hydrazine and/or hydroxylamine in a downstream treatment unit in fluid connection with said reactor.

18. A reactor system for the conversion of biomass to furanic compounds, comprising: optionally a pre-treatment section, a reactor comprising an inlet and an outlet wherein the reactor is configured for continuous operation and for transport of components of a reaction medium from an inlet to an outlet, a pulsating device in fluid communication with said reactor for providing reciprocating flow to a reaction medium in said reactor, one or more separation units downstream of said reactor for solid/liquid separation and for liquid/liquid separation of a reactive phase from an extractive phase of the reaction medium, a recovery unit for recovering product from the separated extractive phase, and a recycling loop from said recovery unit to said reactor for recycling of the extractive phase.

19. The process of claim 8, wherein said feed materials comprise mixing of two or more different heterogeneous feed materials.

20. The process of claim 9, wherein said organic phase comprises 2-methoxyphenol.

21. The reactor system of claim 18, wherein said recycling loop is a recycle loop for said reactive phase to said reactor.

22. The reactor system of claim 18, which further comprises a downstream processing unit in fluid connection with said reactor for subjecting formed furanic compounds to chemical reactions, having an inlet for receiving the separated extractive phase.

Description

EXAMPLES

Example 1: Xylose Conversion in Biphasic Reactor

[0117] A 1:1 mixture of 2-sec-butylphenol and 100 g/L xylose solution, which was adjusted to pH 1 with sulfuric acid, was fed to an oscillating baffled reactor with a total flow rate of 5 kg/hr. The mean residence time in the reactor was 30 minutes and the amplitude and frequency of oscillations were 40 mL and 0.16 Hz, respectively. Hence, the ratio between maximum oscillatory flow rate and net flow rate was about 14.5. The temperature of the reactor was 160 C. The oscillations resulted in a pressure fluctuation of about 7.5 bar around the operating pressure of 20 bar. The high pressure was sufficient to prevent boiling of the water phase. Samples were taken every 30 minutes. They were analyzed by means of HPLC analysis and contained about 18% furfural on average. The furfural yield was quite constant over the complete 3 hours of run time (see table 1). This indicates a feasible continuous process for xylose conversion into a furanic compound in a biphasic reactor.

TABLE-US-00001 TABLE 1 Furfural Residual Sample yield Xylose 1 19.9% 0.3% 2 18.0% 0.4% 3 18.2% 0.4% 4 17.1% 0.4% 5 17.9% 0.4% All 20.6% 0.3% samples combined

Example 2: Pulsed Column with Fibrous Solids

[0118] Example 2 illustrates flow experiments with fibrous solids in water and organic solvent/water mixtures.

[0119] FIG. 3 shows a schematic representation of the setup in which flow experiments were conducted in a pulsed column of fibrous solids in water. Solid fibrous material of different fiber lengths (d=20 m, 1=60-900 m) were mixed with water in a stirred supply vessel (1). A pump (2) fed the mixture to the column (3) with flow rates of typically 4-8 L/hr. The column is equipped with structures protruding the flow (for example, baffles, static mixers of any kind, like rings, twisted plate inserts, corrugated sheets, or unstructured packing material) to break up flow patterns and create vortices that enhance mixing in the column. A pulsator (4) superimposed an oscillatory flow onto the net flow rate supplied by the pump. As a result, the mixture moves through the column forward and backward, but with a net positive displacement. The frequency of oscillations was between 0.1 and 4 Hz, the amplitude was between 7 and 42 mL, depending on the fiber concentration and the fibre length. Consequently, the ratio between maximum pulsation flow rate and feed flow rate was for example minimum 1 and maximum 80, preferably between 2 and 40. The concentration of fibers that could be processed was strongly dependent upon the fiber length: the longer the fibers, the lower the concentration needs to be. Concentrations typically between 0 and 5%-w/w were used. Ensuring that the volume percentage of the settled fiber bed was at most 20, provided the advantage of preventing blockage in the lines or in the pump.

Example 3: Pulsed Column and Product Extraction

[0120] Example 3 illustrates flow experiments with organic solvent/water mixtures. In the same setup as for Example 2, also experiments were performed with an apolar organic solvent and water. This was done to investigate the conditions needed for the extraction of product from the aqueous phase to an organic phase. It was found that imposing, pulsations in the flow stimulated droplet breakup and increased mass transfer area. It was found that increasing the intensity of the pulsations was best achieved by increasing the pulsation frequency, while limiting the amplitude. This is necessary to maintain a plug-flow like behavior in the reactor, while increasing the power input for droplet breakup. Settings of flow and pulsator were equal to the liquid solid experiments, the volume ratio of water to organic phase was chosen between 1:4 and 4:1.

Example 4: Batch Conversion of Heterogeneous Solid Waste

[0121] A pressure tube was mounted with a magnetic stirring bar and filled with given type and amounts of salt, heterogeneous solid waste, acid catalyst and solvent. The tube was sealed with a crimp-cap. The tube was subsequently introduced into a microwave reactor which stirred and heated the reaction mixture at the given temperature and for the given time by means of microwave radiation. After the reaction, the concentrations of monosaccharide, furanics and acids in the aqueous and solvent phase were determined by means of HPLC analysis.

[0122] FIG. 4 shows the obtained yield for the conversion of sewage sieve fraction with different solvents at the following conditions: 75 g/L sewage sieve fraction, 71 g/L NaCl, reaction volume=3 mL, 100 mM HCl, and reaction times of 22 and 45 minutes. SBP=2-sec-butylphentol, MIBK=methyl iso-butylketone and 2-MeTHF=2-methyl-tetrahydrofuran.

[0123] FIG. 5 shows the conversion of sewage sieve fraction with different acid catalysts at the following conditions: 50 g/L sewage sieve fraction, 71 g/L NaCl, 2-sec-butylphenol:water-ratio=1, reaction volume=3 mL, acid type as indicated at pH 1, 200 C. and reaction time=45 minutes.

[0124] FIG. 6 illustrates the conversion with various types of heterogeneous solid biomaterial (biogenic) waste materials. The conversion of different heterogeneous solid biogenic waste types is shown for 50 g/L and 100 g/L, 71 g/L NaCl, 2-sec-butylphenol:water-ratios indicated, reaction volume=3 mL, 100 mM HCl, 200 C. and a reaction time of 45 minutes. SSO=source separated organics.

Example 5: Telescoping of HMF Via Hydrazone to Aromatic in 2-Sec-Butylphenol

[0125] ##STR00002##

[0126] To a reactor was charged 2-sec-butylphenol (8.81 mL) and upon stirring, 5-(hydroxymethyl)furfural (HMF) (2520 mg) and, after 2 minutes, 1,1-dimethylhydrazine (1260 mg, 1600 L), which was added dropwise. The reaction mixture was stirred at 20 C. for 1 hour, after which the mixture was an orange/brown solution. LCMS analysis at this point revealed nearly complete conversion to the desired hydrazone intermediate. The resulting yellow/brown hydrazone solution was carried through into the following reaction without any further purification/work-up.

[0127] To the reactor containing the yellow/brown hydrazone solution was charged N-ethylmaleimide (250.3 mg), whilst stirring at 20 C. After 1 hour the reaction product appeared as a precipitate and LCMS analysis revealed near complete conversion to the desired aromatic product.