SYSTEMS AND METHODS FOR FORMALDEHYDE CONTROL

Abstract

Methods are provided to use water-free quench liquids to obtain pyrolytic liquid products with reduced formaldehyde content. Products include liquids with improved hydroxyacetaldehyde content.

Claims

1. A method for producing a low-formaldehyde product having a ratio of no more than 150 ppm formaldehyde per 1° BX of the low-formaldehyde product, comprising: i) pyrolyzing biomass to form gaseous pyrolysis products; ii) condensing a portion of the gaseous pyrolysis products to form the low-formaldehyde product, comprising: contacting the gaseous pyrolysis products with a nonaqueous coolant; and iii) separating at least a portion of the low-formaldehyde product from the nonaqueous coolant.

2. A method for producing a low-formaldehyde liquid product having a ratio of no more than 150 ppm formaldehyde per 1° BX of the low-formaldehyde liquid product, comprising: i) pyrolyzing one or more biomass components to form gaseous pyrolysis products; ii) introducing the gaseous pyrolysis products into a separation unit; iii) recirculated a liquid coolant having a water solubility at 25° C. of less than 100 ppm water from an outlet of the separation unit to an inlet of the separation unit; and iv) recovering the liquid product comprising at least 50 wt. % of the gaseous pyrolysis products from the separation unit.

3. A method for producing a low-formaldehyde liquid product having a ratio of no more than 150 ppm formaldehyde per 1° BX of the low-formaldehyde liquid product, comprising: i) pyrolyzing biomass in a biomass-containing stream to form a gaseous pyrolytic stream comprising water; ii) introducing the gaseous pyrolytic stream into a separation unit; iii) recirculating a substantially water-free liquid coolant stream from an outlet of the separation unit to an inlet of the separation unit; and iv) recovering substantially all of the water present in the gaseous pyrolytic stream from the separation unit in a first stream consisting of the liquid product and a second stream consisting of a non-condensed portion of the gaseous pyrolytic stream.

4. The method of claim 1, wherein the biomass comprises one or more sugars and/or one or more starches.

5. The method of claim 1, wherein the one or more sugars comprises a simple sugar.

6. The method of claim 1, wherein the biomass comprises an impure mixture of different sugars.

7. The method of claim 1, wherein the one or more starches comprises one or more of corn starch, potato starch, wheat starch, oat starch, tapioca starch and rice starch.

8. The method, system, and/or apparatus of claim 1, wherein the biomass comprises a cellulosic biomass.

9. The method, system, and/or apparatus of claim 1, wherein the particulate solid is provided in a carrier gas.

10. The method of claim 1, wherein the low-formaldehyde product is a browning agent.

11. The method of claim 1, wherein the low-formaldehyde product is a microwave browning agent.

12. The method of claim 1, wherein the low-formaldehyde product is a binder.

13. The method of claim 1, wherein the low-formaldehyde product may be processed into a binder.

14. The method of claim 1, wherein a binder is derived from the low-formaldehyde product.

15. The method of claim 1, wherein the low-formaldehyde product is a chemical.

16. The method of claim 1, wherein the low-formaldehyde product may be processed into a chemical.

17. The method of claim 1, wherein a chemical is derived from the low-formaldehyde product.

18. The method of claim 1, wherein the low-formaldehyde product is rich in a certain chemical.

19. The method of claim 1, wherein the low-formaldehyde product is a solvent.

20. The method of claim 1, wherein the low-formaldehyde product may be processed into a plastic.

Description

DETAILED DESCRIPTION OF THE DRAWINGS

[0111] FIG. 1 is a schematic depiction of a thermal process comprising a nonaqueous quench condenser.

[0112] FIG. 2 is a schematic depiction of a thermal process comprising a formaldehyde removal component.

[0113] FIG. 3 is a schematic depiction of an upflow thermal process using a formaldehyde-free lift gas.

[0114] FIG. 4 is a schematic diagram of a rapid thermal processing system.

DETAILED DESCRIPTION OF THE INVENTION

[0115] The present disclosure is based, generally and in combination with other aspects disclosed herein, on the discovery that water present during quenching and condensation of thermally generated (for example pyrolytic) gases plays a significant role in determining the formaldehyde content of pyrolytic condensates. Providing a low water condensing environment, for example, can significantly reduce formaldehyde concentration in pyrolytic condensates, both in absolute terms and relative to desired chemical constituents. The present disclosure is further specifically based, in part, on the discovery that significant formaldehyde reduction can be achieved by employing a nonaqueous quench liquid in a primary quench condenser. Moreover, it has been discovered that elimination of water carrier from pyrolysis feedstocks can reduce formaldehyde concentration in condensed product condensates.

[0116] A schematic depiction of thermal process (for example one of the thermal processes disclosed in the INCORPORATED REFERENCES such as fast pyrolysis) embodiment 100 comprising a thermal reactor 102 and a quench condenser 104 is shown in FIG. 1. A biomass 106 is converted in the thermal reactor 102 to a thermal product gas 108 which is introduced to the quench condenser 104 and at least partially condensed to form a liquid product 110. The quench condenser 104 uses a nonaqueous quench medium to cool the thermal product gas 108 to form the liquid product 110.

[0117] The thermal reactor 102 can be any type of low oxygen thermal reactor effective to at least partially pyrolyze the biomass. The thermal reactor 102 can be any of the thermal reactors disclosed in the INCORPORATED REFERENCES. The thermal reactor 102 can be an upflow reactor using heat carrier particles in an entrained lift gas to mix with the biomass. The thermal reactor 102 can be a fluidized bed reactor. The thermal reactor 102 can be a rotating cone reactor. The thermal reactor 102 can be an ablative reactor. The thermal reactor 102 can be a screw or auger reactor.

[0118] The quench condenser 104 can comprise a single vessel. The quench condenser 104 can be any of the quench condensers disclosed in the INCORPORATED REFERENCES. The quench condenser 104 can comprise a multitray distillation column. The quench condenser 104 may comprise a recirculation loop to recirculate the quench medium from a lower portion of the quench condenser 104 to an upper portion of the quench condenser 104. The recirculation loop can include a heat exchanger to cool the quench medium. The quench condenser 104 can include a settling zone in a lower portion of the quench condenser 104 to provide phase separation between the quench medium and the liquid product. The quench condenser 104 may be in communication with a settling vessel to provide phase separation between the quench medium and the liquid product, and the quench medium returned to the quench condenser 104.

[0119] The nonaqueous quench medium can be selected from the nonexclusive group consisting of a petroleum-based liquid, liquid hydrocarbon, an unsaturated liquid hydrocarbon, a saturated liquid hydrocarbon, a hexane, a heptane, dodecane, a vegetable oil, diesel, a polysorbate, a polymer, a silicone oil, or a combination of two or more of the foregoing. The nonaqueous quench medium can be one or more of the quench media disclosed in the INCORPORATED REFERENCES.

[0120] The biomass 106 can be introduced to the thermal reactor 102 as a particulate solid. The biomass 106 can be introduced to the thermal reactor 102 as a suspension in a liquid, such as a suspension in water or a suspension in a nonaqueous coolant medium. The biomass 106 can be introduced to the thermal reactor 102 dissolved in an aqueous solution. The biomass 106 can be one or more of the biomasses disclosed herein and/or in the INCORPORATED REFERENCES. The biomass 106 can be a biomass selected from the non-exclusive group consisting of: a carbohydrate-containing biomass, a sugar-containing biomass (for example potatoes, sugar beets, milk such as cow's milk, or corn syrup), a starch (for example corn starch, potato starch, wheat starch, oat starch, tapioca starch, or rice starch), a monosaccharide, a disaccharide, a trisaccaride, a polysaccharide, glucose, glyceraldehyde, threose, erythrose, ribose, arabinose, xylose, lyxose, allose, altrose, mannose, gulose, idose, galactose, talose, sorbose, cellobiose, a glucose-containing polysaccaride, dextrose, invert sugar, lactose, malt syrup, molasses, starch hydrolysates and fractions thereof, fructose, maltose, sucrose, a cellobiose-containing biomass, a hemi-cellulose-containing biomass, a cellulose-containing biomass, wood, hardwood, softwood, bark, agricultural residues, silvicultural residues, seed, nuts, leaves, fruit fiber, plant-derived syrup, plant-derived extract, algae, grasses, forestry residues, municipal solid waste, construction and/or demolition debris, lignin-containing biomasswood residues, sawdust, slash bark, thinnings, forest cullings, begasse, corn fiber, corn stover, empty fruit bunches (EFB), fronds, palm fronds, flax, straw, low-ash straw, energy crops, palm oil, non-food-based biomass materials, crop residue, slash, pre-commercial thinnings and tree residue, annual covercrops, switchgrass, miscanthus, cellulosic containing components, cellulosic components of separated yard waste, cellulosic components of separated food waste, cellulosic components of separated municipal solid waste (MSW), holocellulose-containing biomass, for example, grasses, straw, paper, pulp, pulp residues, whitewood, partially de-lignified wood, other biomass carbonaceous feedstocks, or a combination of two or more of the foregoing.

[0121] The thermal product gas 108 can comprise a mixture of thermal degradation products of the biomass (for example any of the thermal degradation products disclosed in the INCORPORATED REFERENCES). The thermal product gas 108 can comprise hydrogen. The thermal product gas 108 can comprise methane. The thermal product gas 108 can comprise water. The thermal product gas 108 can comprise oxygen-containing hydrocarbons. The thermal product gas 108 can comprise one or more alcohols. The thermal product gas 108 can comprise one or more organic acids. The thermal product gas 108 can comprise one or more aldehydes. The thermal product gas 108 can comprise formaldehyde. The thermal product gas 108 can comprise hydroxyacetaldehyde (also referred to as glycolaldehyde). The thermal product gas 108 can comprise one or more carbonyl-containing compounds. The thermal product gas 108 can comprise formaldehyde. The thermal product gas 108 can comprise acetic acid. The thermal product gas 108 can comprise acetol. The thermal product gas 108 can comprise cyclotene. The thermal product gas 108 can comprise one or more of: 2-methoxyphenol; 2-methoxy-4-methylphenol; 4-ethyl-2-methoxyphenol; 1,4-dimethoxy-2-methylphenol; 2-methoxy-5-(or 4,6)(1-propenyl) phenol; 2,6-(or 3,4-) dimethoxyphenol; 2-methoxy-5-(or 4, or 6)(1-propenyl) phenol; 4-hydroxy-3-methoxybenzoic acid or 2,5-dimethoxybenzyl alcohol; (1,1-dimethylethyl)-1,2-benzenediol or 1-(4-hydroxy-3-methoxyphenyl)ethanone; 3,4-dimethoxybenzoic acid; 2,6-dimethoxy-4-(2-propenyl)-phenol; and 3,4′ (or 3,3′ or 4,4′)-1,1′-biphenyl. The thermal product gas 108 can comprise an inert gas (for example an inert lift gas used in the thermal reactor).

[0122] The liquid product 110 can comprise a mixture of thermal degradation products of the biomass. The liquid product 110 can comprise water. The liquid product 110 can comprise oxygen-containing hydrocarbons. The liquid product 110 can comprise one or more alcohols. The liquid product 110 can comprise one or more organic acids. The liquid product 110 can comprise one or more aldehydes. The liquid product 110 can comprise formaldehyde. The liquid product 110 can comprise hydroxyacetaldehyde. The liquid product 110 can comprise one or more carbonyl-containing compounds. The liquid product 110 can comprise formaldehyde. The liquid product 110 can comprise acetic acid. The liquid product 110 can comprise acetol. The liquid product 110 can comprise cyclotene. The liquid product 110 can comprise one or more of: 2-methoxyphenol; 2-methoxy-4-methylphenol; 4-ethyl-2-methoxyphenol; 1,4-dimethoxy-2-methylphenol; 2-methoxy-5-(or 4,6)(1-propenyl) phenol; 2,6-(or 3,4-) dimethoxyphenol; 2-methoxy-5-(or 4, or 6)(1-propenyl) phenol; 4-hydroxy-3-methoxybenzoic acid or 2,5-dimethoxybenzyl alcohol; (1,1-dimethylethyl)-1,2-benzenediol or 1-(4-hydroxy-3-methoxyphenyl)ethanone; 3,4-dimethoxybenzoic acid; 2,6-dimethoxy-4-(2-propenyl)-phenol; and 3,4′ (or 3,3′ or 4,4′)-1,1′-biphenyl. The liquid product 110 can comprise an inert gas (for example an inert lift gas used in the thermal reactor).

[0123] A schematic depiction of a thermal process embodiment 200 comprising a thermal reactor 202, one or more liquid recovery components 204, and a formaldehyde removal component 206 is shown in FIG. 2. A biomass 208 is converted in the thermal reactor 202 to a thermal product gas 210 which is introduced to the one or more liquid recovery components 204 and at least partially condensed to form a formaldehyde-containing condensate 212. The formaldehyde-containing condensate 212 is passed through the formaldehyde removal component 206 to form a liquid product 214. The liquid product 214 has a lower concentration of formaldehyde than the formaldehyde-containing condensate 212. The thermal reactor 202 may be any of the thermal reactors disclosed herein or in the INCORPORATED REFERENCES. The one or more liquid recovery components 204 may comprise one or more of the quench condensers disclosed herein. The one or more liquid recovery components 204 may comprise a chiller. The one or more liquid recovery components 204 may comprise a fiber bed filter. The one or more liquid recovery components 204 may comprise a demister. The formaldehyde removal component 206 can comprise an evaporator. The evaporator can operate under reduced pressure (for example under a vacuum). The formaldehyde removal component 206 can comprise a bentonite addition and filtration tank. The biomass 208 can be one or more of the biomasses disclosed herein and/or in the INCORPORATED REFERENCES. The thermal product gas 210 can comprise one or more of the thermal product gas components disclosed herein and/or in the INCORPORATED REFERENCES. The formaldehyde-containing condensate 212 and/or the liquid product 214 can comprise one or more of the liquid product components disclosed herein and/or in the INCORPORATED REFERENCES.

[0124] A schematic depiction of a thermal process embodiment 300 comprising an upflow fast pyrolysis reactor 302 and one or more liquid recovery components 304 is shown in FIG. 3. A biomass 306 and formaldehyde-free lift gas 308 are introduced into the fast pyrolysis reactor 302 whereby the biomass 306 is converted to pyrolysis gas 310 comprising the lift gas 308 mixed with pyrolysis products. The pyrolysis gas 310 to the one or more liquid recovery components 304 and at least partially condensed to form a liquid product 312 and non-condensed pyrolysis gas 314. The one or more liquid recovery components 304 may comprise any of the one or more liquid recovery components disclosed herein and/or in the INCORPORATED REFERENCES. The biomass 306 can be one or more of the biomasses disclosed herein and/or in the INCORPORATED REFERENCES. The formaldehyde-free lift gas 308 can be a non-recirculated gas. The formaldehyde-free lift gas 308 can be an oxygen-free or low oxygen (for example less than 5 wt. % oxygen, less than 1 wt. % oxygen, or less than 0.5 wt. % oxygen) gas. The formaldehyde-free lift gas 308 can be a combustion flue gas (for example a combustion flue gas from an inorganic particle reheater). The pyrolysis gas 310 and/or the liquid product 312 can comprise one or more of the liquid product components disclosed herein and/or in the INCORPORATED REFERENCES. The non-condensed pyrolysis gas 314 can comprise formaldehyde. The non-condensed pyrolysis gas 314 can comprise a hydrocarbon. The non-condensed pyrolysis gas 314 can comprise carbon monoxide or carbon dioxide.

[0125] A rapid thermal processing system 400 for thermal conversion of biomass is shown in FIG. 4. A feed system 402 provides a regulated flow of solid biomass feedstock to an upflow fast pyrolysis reactor 404. Alternatively, the feed system 402 may be replaced with a liquid feed system comprising a liquid supply tank, pump, and spray equipment for the biomass to be introduced to the reactor 404 as a liquid stream (for example a biomass dissolved or suspended in water). The reactor can be operated at slightly above atmospheric pressure (i.e., sufficient pressure to overcome the back pressure of the downstream equipment), and the feed system 402 can provide material under slight pressure (1.2 atmospheres) while at the same time accepting feedstock material which is at atmospheric pressure.

[0126] When the feedstock is a particulate solid, a constant speed screw conveyor 406 constructed of stainless steel and provided with high temperature seals and bearings introduces the biomass to the reactor 404.

[0127] The reactor 404 mixes the biomass with an upward flowing stream of lift gas and hot heat carriers, e.g., sand, in a mixing zone of the reactor 404 to achieve thorough and rapid mixing and conductive heat transfer from the heat carriers to the biomass. The hot heat carriers instantly flash the feedstock into a hot vapor, which is cooled, condensed, and recovered downstream as a liquid product.

[0128] Rapid pyrolysis of the feedstock is initiated in the mixing zone under moderate temperatures (for example at a temperature in the range of 400° C. to 550° C.), through to a separation system comprising two cyclonic separators (408 and 410) located downstream of the reactor 404. The resident time in the reactor is preferably less than 5 seconds, and more preferably less than 2 seconds. The solid heat carriers along with by-product char are removed from the product vapor stream by the two cyclonic separators (408 and 410). The first cyclonic separator 408 separates the solid heat carriers and by-product char from the product stream. The solids that have been removed in the first separator 408 are directed to a reheater unit 412. In the reheater unit 412, the by-product char is converted by the addition of air to heat and combustion gases. Typically, there is more than sufficient heat generated by the combustion of by-product char and gas to satisfy the heat requirements of the thermal conversion process (external fuels, such as natural gas, are rarely used and typically for system start-up alone). The excess heat from the reheater can be productively used for other purposes, including biomass drying, steam generation, space heating, power generation, etc. The heat generated in the reheater elevates the temperature of the solid heat carriers, which can then be transferred to the feedstock material in the reactor 404 to achieve the necessary reaction temperatures.

[0129] The second separator 410 removes char that is not removed in the first separator 408 and passes a product vapor stream via an insulated duct to a quench condenser 414. Preferably, the product vapor stream is brought from a conversion temperature of approximately 350° C. to 600° C., to less than 100° C. in less than 1 s. More preferably, the hot vapor stream is reduced to less than 50° C. in less than 0.1 s (100 ms), and most preferably to a temperature of less than 50° C. in less than 20 ms. The quench condenser 414 is equipped with a liquid distributor 53 416 located in the upper portion of the condenser 414. Nonaqueous quench media that is at least partially immiscible with pyrolysis liquid condensate is circulated through the distributor 416 and allowed to “rain” down on the incoming vapor stream. Various types of distributor systems can be employed. Examples include, but are not limited to, vane, pipe, chimney, finger distributor, spray head, nozzle design, trays, packing, etc. Preferably, at least 10 gpm/sq. ft (gallons per minute/sq. ft) of column cross-sectional diameter of quench liquid is circulated through the collection column. More preferably, at least 50 to 100 gpm/sq. ft of column cross-sectional diameter of quench liquid is circulated through the collection column. The dense stream of liquid raining down the column not only serves to immediately cool and quench the incoming vapor but also provides nucleation sites for the collection of the liquid product. Typically, the hot vapor enters the quench condenser 414 just above the normal operating level of the collected liquid in the condenser 414. The vapor not collected in the condenser 414 along with the non-condensable gas exit the condenser 414 through a top exit port 418. This mode of operation is counter-current. In another mode of operation in which it is desired to minimize the length of the hot vapor piping the hot vapor enters through the upper portion of the condenser 414 and the vapor not collected in the condenser 414 along with the non-condensable gas exit through a port situated in the lower portion of the condenser 414 (just above the normal liquid level). This mode of operation is co-current. The condenser 414 may be equipped with a demister in the gas exit section of the column to reduce the carryover of liquid droplets into a secondary collection column 420.

[0130] Condensate of the pyrolysis gases flows to the lower portion of the condenser 414 with the nonaqueous quench, where the condensate and quench medium for two distinct phase. A portion of the condensate is drawn out from the condenser 414 as liquid product while a portion of the quench phase is pumped by a condenser pump 57 422 through a heat exchanger 424 to cool the quench, e.g., 30 to 50° C. The cooling medium for the heat exchanger 424 can be water. Other cooling means may be employed including a glycol system, an air cooler, or the like. The cooled quench is recirculated to the condenser 414.

[0131] The liquid product in the collection column is pumped out to product storage tanks (not shown) to maintain the desired liquid level. The collected liquid product provides a valuable liquid product, bio-oil, that can be used, e.g., for fuel and/or other commercial uses.

[0132] The vapor is rapidly quenched because the vapor and liquid product are thermally labile (chemically react at higher temperatures). By using a high liquid recirculation/quench rate, the incoming vapor is rapidly quenched, which avoids undesirable chemical reactions such as polymerization that occur at higher temperatures. Further, the high recirculation rate of the liquid product used for the quench media prevents the quench media from reaching undesirably high temperatures.

[0133] The secondary collection column 420 may use pyrolysis vapor condensate or a different quench medium via an overhead distribution system 426. Preferably, at least 10 gpm/sq. ft of column cross-sectional diameter of liquid is circulated through the secondary collection column 420. More preferably, at least 50 to 100 gpm/sq. ft of column cross-sectional diameter of quench liquid is circulated through the secondary collection column 420. The secondary collection column 420 may be equipped with a demister in the gas exit section of the secondary collection column 420 to reduce the carryover of liquid droplets, mist or aerosols into the downstream demister or filtering systems. The cross-sectional diameter of the secondary collection column 420 may be the same as the quench condenser secondary collection column 420. However, the secondary collection column 420 is typically smaller in diameter since greater superficial gas velocities will facilitate the removal of the fine droplets or aerosols in the demister section of the secondary collection column 420.

[0134] Mist, aerosols and non-condensable gas that exit the secondary collection column 420 are directed to a separate demister system 428. If the secondary collection column 420 is equipped with an internal demister unit, then the downstream separate demister system 428 may not be required. The demister system 428 preferably removes mist droplets that are greater than 3 microns. These droplets tend to be captured in the demister by inertial impaction. The particles, which are traveling in the gas stream, are unable to abruptly change direction along with the gas as the flow goes through the demisting system 428 due to their weight. As a result, they impact the fibers of the demister and are subsequently captured. Mist particles that come in contact with the demister fibers adhere by weak Van Der Waals forces. The accumulating impacting mist droplets tend to join together to form larger single droplets that finally fall to the lower portion of the demister vessel due to gravitational sedimentation.

[0135] The demister system 428 may comprise a series of mist eliminator units. The first unit is a vane mist eliminator which can remove about 99% of the mist as low as 10 microns. Next is a stainless steel wire mesh pad having a density of about 5 lbs/ft3 and a wire diameter of 0.011 inches (surface area of 45 ft2/ft3, and 99.0% voids). Other materials may be used besides steel including glass, alloy 20, Teflon, polypropylene, or the like. This is followed by a 9 lb/ft3 stainless steel wire mesh pad, again 0.011 inch diameter (surface area of 85 ft2/ft3, and 98.0% voids). The final mist eliminator unit is a co-knit style comprising a metal wire construction with fiberglass. The pad is 9 lb/ft3 with a wire diameter of 0.00036 inches (surface area of 3725 ft2/ft3, and 99.0% voids).

[0136] Fine aerosols (i.e., less than approximately 3 microns), condensed particles of greater than 3 microns that evaded the demister system 428, and non-condensable gas from either the secondary condensing column 60 or the demister system 428 pass to a final filtering system. The filter system may comprise two fiber beds 430 and 432 set up in parallel, as shown. Again, as was the case with the demister system 428, particles larger than about 3 microns are captured by inertial impaction. Condensed particles between 1 and 3 microns tend to be captured through interception in which the particles follow the non-condensable gas stream line that comes within about one particle radius of the surface of a fiber. Particles of less than 1 micron are captured through diffusion or Brownian movement in which the particles have a tendency to attach themselves to the fibers of the filters (430 and 432) due to their random motion. Again, captured particles tend to join together to form larger liquid droplets. However, the pressure drop across the filters (430 and 432) may exceed predetermined limits before a sufficient quantity of material has drained to the lower section of the filter vessel. In addition, re-entrainment of collected material can occur as the localized loading of liquid increases the effective open cross-sectional area of the filter decreases thereby increasing the flow of gas through the remaining open areas. This increase flow of gas leads to increased velocities that can lead to higher than desired pressure drops and possibly re-entrainment, and loss of captured liquid. Therefore, the filters (430 and 432) can consist of more than one filter unit which can be set up in parallel or in series as required. Typically two filters are employed in parallel in which one filter unit is on-line at any one time. A filter unit may remain on-line for a period of about 8 to 24 hours (typically 12 hours). When a filter is switched off-line it is allowed to drain. The pressure drop across the filter unit can also dictate the period of time that the unit is allowed to remain on-line. Pressure drops that exceed predetermined limits (typically 100 inches of water column) can lead to failure of filter elements (i.e., tear holes can develop in the fabric).

[0137] Since the collected mists and aerosol liquid can tend to be relatively viscous at ambient conditions a reheat exchanger 434 can be employed between the secondary condenser column 420 and the demister system 428 and fiber bed filters (430 and 432). Alternatively, if the demister is incorporated in the secondary condenser column 420, the reheat exchanger will be installed upstream of the fiber bed filters (430 and 432) only. The reheat exchanger 434 is used to slightly elevate the temperature of the vapor stream (up to about 60-65° C.) and enable a sufficient viscosity reduction of the captured liquids in the downstream systems to allow adequate drainage.

[0138] The gas filtered through the filters (430 and 432) is recycled back to the reactor 404 by a reactor blower 436. To provide lift gas. Alternatively, a non-recycled, formaldehyde-free lift gas (for example 100% nitrogen gas from a cryogenic source) may be provided.

INCORPORATION BY REFERENCE

[0139] Without limitation, the following documents are hereby incorporated, in their entirety, by reference: U.S. Pat. Nos. 2,307,937; 4,101,412; 4,876,108; 5,135,770; 5,252,188; 5,292,541; 5,397,582; 5,840,362; 5,961,786; 6,485,841; 7,572,362; U.S. Patent Application Publication Nos. 2004/0022912; 2012/0022171; 2014/0053456; 2015/0191656; 2016/0002137; 2016/0024037; 2017/0275545; 2018/0334618; International (PCT) Patent Application Publication Nos. WO 1998/000935; WO 2018/017664; and European Patent No. EP1311615 (collectively, the “INCORPORATED REFERENCES”).

EXAMPLES

[0140] In Examples 1-2 and Comparative Example A, glucose fast pyrolysis experiments were performed in a bench scale reactor and liquid products obtained from a sequence of recovery units that included a quench condenser, a secondary condenser (chiller), a fiber bed filter, and a demister. In Comparative Samples 1-2, liquid samples obtained from operating pyrolysis plant were obtained and analyzed. Results are shown in Table 1. Analysis details are shown in Tables 2-3.

TABLE-US-00001 TABLE 1 Results for liquid samples obtained from quench condenser. Aqueous Browning Agent Samples Comparative from Operating Pyrolysis Plant.sup.4 Ratio Example 1.sup.1 Example 2.sup.2 Example A.sup.3 Sample 1 Sample 2 Hydroxyacetaldehyde:BRIX (wt. %/°BX) 0.47 0.50 0.50 0.68 0.60 Formaldehyde:Hydroxyacetaldehyde (w/w) 0.018 0.006 0.076 0.03 0.03 Formaldehyde:BRIX (ppm/°BX) 84 31 382 172 178 .sup.165 °BX solution of glucose was pyrolyzed in a continuous upflow reactor utilizing sand heat transfer particles and once-through nitrogen lift gas, and pyrolysis vapors quenched with liquid dodecane in a quench condenser. .sup.2Solid glucose particles were pyrolyzed in a continuous upflow reactor utilizing sand heat transfer particles and once-through nitrogen lift gas, and pyrolysis vapors quenched with liquid dodecane in a quench condenser. .sup.365 °BX solution of glucose was pyrolyzed in a continuous upflow reactor utilizing sand heat transfer particles and once-through nitrogen lift gas, and pyrolysis vapors quenched with liquid water in a quench condenser. .sup.4A solution of simple sugars was pyrolyzed in continuous upflow reactor utilizing sand heat transfer particles and recirculated lift gas, and pyrolysis vapors quenched with liquid water in a quench condenser.

TABLE-US-00002 TABLE 2 Analysis of fast pyrolysis products in Examples 1-2 and Comparative Example A.sup.1 Liquid Product Fractions Product Liquid Product Fractions Product Filter/ Quench Characteristics, Filter/ Quench Characteristics Condenser Chiller Demister.sup.2 Liquid cont'd Condenser Chiller Demister Liquid EXAMPLE 1 Feed Rate, lb/hr 5.1 Reactor Temperature, ° C. 458 Inlet Feed Temperature, ° C. 80 Condenser Temperature, ° C. 50 Formaldehyde, ppm 4850 NT NT <340 Water, wt. % 35.4 92.3 36.5 N/A Hydroxyacetaldehyde, wt. % 27.0 0.68 13.8 NT Ash, wt. % 0.17 <0.01 0.10 N/A BRIX, °BX 57.6 5.8 57.3 NT Solids, wt. % 0.22 <0.01 0.09 N/A Acetic acid equiv., wt. %.sup.3 1.9 0.6 1.8 NT Specific Gravity 1.25 1.10 2.25 NT Carbonyl content, g/100 mL.sup.4 44.7 7.5 50.7 NT pH 2.9 2.7 2.8 N/A EXAMPLE 2 Feed Rate, lb/hr 3.9 Reactor Temperature, ° C. 475 Inlet Feed Temperature, ° C. — Condenser Temperature, ° C. 55 Formaldehyde, ppm.sup.3 2530 NT NT NT Water, wt. % 9.1 77.4 11.6 N/A Hydroxyacetaldehyde, wt. % 40.7 4.61 34.2 NT Ash, wt. % 2.75 0.02 NT N/A BRIX, °BX 82.1 18.3 77.1 NT Solids, wt. % 2.62 0.01 NT N/A Acetic acid equiv., wt. % 2.4 2.0 2.2 NT Specific Gravity 1.4 1.1 1.3 NT Carbonyl content, g/100 mL 106.5 39.5 97.8 NT pH 3.2 2.4 3.4 N/A COMPARATIVE EXAMPLE A Feed Rate, lb/hr 4.9 Reactor Temperature, ° C. 485 Inlet Feed Temperature, ° C. 80 Condenser Temperature, ° C. 37 Formaldehyde, ppm.sup.3 6030 NT NT N/A Water, wt. % 85.5 99.1 44.4 N/A Hydroxyacetaldehyde, wt. % 7.91 ND 6.91 N/A Ash, wt. % 0.04 <0.01 0.18 N/A BRIX, °BX 15.8 2.1 53.7 N/A Solids, wt. % 0.82 0.02 0.10 N/A Acetic acid equiv., wt. % 0.6 0.3 1.9 N/A Specific Gravity 1.06 1.02 1.21 N/A Carbonyl content, g/100 mL 13.6 2.3 78 N/A pH 3.0 3.1 3.2 N/A .sup.1Liquid samples collected from a quench condenser, chiller, fiber bed filter, and demister. .sup.2Liquid samples from fiber bed filter and demister were combined for analysis. .sup.3Acetic Acid Equivalents, inclusive of acetic acid, formic acid, and propionic acid. .sup.4Liquid product components containing carbonyl functional group.

TABLE-US-00003 TABLE 3 Analysis of aqueous browning agent samples obtained from operating pyrolysis plant.sup.1 Liquid Product Fractions Liquid Product Fractions Primary Secondary Product Primary Secondary Product Quench Quench Filter Characteristics, Quench Quency Filter Characteristics Condenser Condenser Bed Demister cont'd Condenser Condenser Bed Demister SAMPLE 1 Formaldehyde, ppm 8500 NT NT NT Water, wt. % N/A N/A N/A N/A Hydroxyacetaldehyde, wt. % 33.6 12.9 7.4 10.3 Ash, wt. % N/A N/A N/A N/A BRIX, °BX 49.3 53.5 53.0 61 Solids, wt. % N/A N/A N/A N/A Acetic acid equiv., wt. % 2.4 2.7 3.6 3.8 Specific Gravity 1.22 1.23 1.22 1.27 Carbonyl content, g/100 mL 71.4 93.7 77.0 91.9 pH N/A N/A N/A N/A SAMPLE 2 Formaldehyde, ppm 8800 NT NT NT Water, wt. % N/A N/A N/A N/A Hydroxyacetaldehyde, wt. % 29.5 13.0 7.3 10.5 Ash, wt. % N/A N/A N/A N/A BRIX, °BX 49.3 53.3 53.0 61 Solids, wt. % N/A N/A N/A N/A Acetic acid equiv., wt. %.sup.3 2.4 2.8 3.7 3.9 Specific Gravity 1.22 1.23 1.23 1.27 Carbonyl content, g/100 mL.sup.4 73.3 89.3 80.8 88.6 pH N/A N/A N/A N/A .sup.1Samples obtained from quench condenser. .sup.2Liquid product fractions of fiber bed filter and demister were combined for analysis. .sup.3Acetic Acid Equivalents, inclusive of acetic acid, formic acid, and propionic acid. .sup.4Liquid product components containing carbonyl functional group.

[0141] All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

[0142] While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.