Prosecution Insights
Last updated: April 19, 2026
Application No. 18/563,934

HYDROTHERMAL TREATMENT OF BIOMASS

Non-Final OA §102§103
Filed
Nov 24, 2023
Examiner
HINES, LATOSHA D
Art Unit
1771
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno
OA Round
1 (Non-Final)
51%
Grant Probability
Moderate
1-2
OA Rounds
3y 6m
To Grant
73%
With Interview

Examiner Intelligence

Grants 51% of resolved cases
51%
Career Allow Rate
478 granted / 944 resolved
-14.4% vs TC avg
Strong +22% interview lift
Without
With
+22.5%
Interview Lift
resolved cases with interview
Typical timeline
3y 6m
Avg Prosecution
73 currently pending
Career history
1017
Total Applications
across all art units

Statute-Specific Performance

§101
0.7%
-39.3% vs TC avg
§103
62.0%
+22.0% vs TC avg
§102
12.9%
-27.1% vs TC avg
§112
15.2%
-24.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 944 resolved cases

Office Action

§102 §103
Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . DETAILED ACTION This Office action is based on the 18/563934 application originally filed November 24, 2023. Amended claims 1-12 and 14-20, filed September 11, 2025, are pending and have been fully considered. Claim 13 has been canceled. Claims 12 and 14-15 are withdrawn from consideration due to being drawn to a nonelected invention. Election/Restrictions Claims 12 and 14-15 are withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected invention, there being no allowable generic or linking claim. Applicant timely traversed the restriction (election) requirement in the reply filed on September 11, 2025. Applicant's election with traverse of Group I claims 1-11 and 16-20 in the reply filed on September 11, 2025 is acknowledged. The traversal is on the ground(s) that further, as amended, claim 12 requires all the steps of the process of claim 1 in making the solid biomass-derived fuel or liquor, and thus claims 1 and 12 relate to a single, general inventive concept with the same special technical features: a process for the treatment of biomass and the products obtained by that process. Thus, applicant respectfully requests that the requirement be withdrawn at least with respect to restricting between Groups I and II. It is also noted that in the International application, the examiner acknowledged that process claim 1 and product claim 12 has unity of invention. This is not found persuasive because while the issue of burden is present in U.S. restriction practice, it does not play a part in restrictions of national stage entry cases. Those cases are restricted based on the claims not sharing a special technical feature as described in PCT Rule 13.2. The requirement is still deemed proper and is therefore made FINAL. Claim Rejections - 35 USC § 102 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. Claim(s) 1-3, 5, 6, 8-10, 18 and 19 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Pels et al. (WO 2019/059768 A1) hereinafter “Pels”. Regarding Claims 1, 5 and 6 Pels discloses in paragraph 0006, the Torwash process could efficiently be performed using the aqueous waste stream POME (palm oil mill effluent), instead of fresh water. High removal rates of potassium and chloride could be obtained, and the obtained solids met the requirements of fuel pellets both in terms of ash content and caloric value. Since POME, which is normally a waste stream, could be used, the usage of fresh water could be minimized, without jeopardizing the effectivity of the Torwash process. A Torwash process wherein POME could be used in the liquid phase, by implementation of a post-wash step. Pels discloses in paragraph 0012, Torwash is a hydrothermal treatment that provides already for a large part the desired salt removal. Pels further discloses in paragraph 0006, a process for the treatment of biomass, comprising: (a) heating a mixture of the biomass and palm oil mill effluent (POME) at a temperature in the range of 100 - 400 °C, to obtain torrefied biomass and a liquor; and (b) washing the torrefied biomass with water, to obtain a washed material and an effluent. Pels discloses in paragraph 0018, the temperature at which the contacting of step (a) is performed is preferably in the range of 100 - 400 °C. Step (a) is typically performed at elevated pressure in order to keep the liquid phase liquid. A typical pressure is slightly above the steam pressure of the operational temperature, and typically is in the range of 4 - 50 bar. The duration of step (a) is typically in the range of 5 min - 5 h. Pels discloses in paragraph 0019, step (a) provides a liquid phase, referred to as liquor or torrefaction liquor, and a solid phase, referred to as torrefied biomass or torrefied material. The torrefied material is fed to step (b), while the liquor is discarded as waste or used as deemed fit. A possible application of the liquor is the production of biogas via digestion. For this application, it may first be combined with the effluent obtained in step (b) and together subjected to digestion, typically anaerobic digestion. The thus obtained biogas can advantageously be used to fuel the palm oil production plant, e.g. for generation of steam. Pels discloses in paragraph 0020, as the skilled person will understand, separation of the liquid and the solid phase is part of step (a). Such separation (or dewatering) can be accomplished in any manner known in the art, such as centrifugation, filtration, draining, decantation and/or mechanically dewatering. Such separation of liquid and solid products may be enhanced, for example by pressing, squeezing or centrifuging the solid material using a porous mould to force out any remaining liquids inside the solid material. Typically, draining, optionally in combination with a centrifuge, is used. As such, significant amounts of undesired ions are already removed by the enhanced dewatering, such that step (b) requires less water to obtain solid fuel with sufficiently low content of such ions. Pels further discloses in paragraph 0022, in step (b), the torrefied solid product originating from step (a) is washed, also referred to as "post-washing". Thus, in one embodiment, the process does not comprise a pre-wash step, or in other words the biomass that is subjected to step (a) is not washed with fresh water prior to step (a). A post-washing step, wherein the torrefied biomass is washed, gave optimal results when POME was used as the liquid phase in the Torwash step. A larger fraction of the undesired elements present in the biomass could be removed by a post-washing step, compared to a pre-washing step. For that reason, it is preferred that the biomass subjected to step (a) of the process is woody or fibrous biomass, as defined above. Pels further discloses in paragraph 0023, the washing of step (b) preferably takes place in counter-current mode, which may be continuous or in stages. For process efficiency, continuous counter-current washing is preferred. Pels discloses in paragraph 0024, in step (b), water is used to remove the bulk of the remaining ions from the torrefied material obtained in step (a). The washing liquid comprises water or preferably is water. In a preferred embodiment, fresh water is used as washing liquid, such as rainwater, surface water or tap water. Pels further discloses in paragraph 0025, the washing of step (b) is typically performed at ambient temperature and pressure. The temperature may be in the range of 10 - 50 °C. The pressure may be in the range of 0.8 - 10 bar. Pels further discloses in paragraph 0027, as the skilled person will understand, separation of the effluent and the washed material is part of step (b). Such separation (or dewatering) can be accomplished in any manner known in the art, such as centrifugation, filtration, draining, decantation and/or mechanically dewatering. Such separation of liquid and solid products may be enhanced, for example by pressing, squeezing or centrifuging the solid material using a porous mould to force out any remaining liquids captured within the solid material. The dewatering may thus afford two liquid streams, a first liquid stream obtained when the solids and the liquids are separated and a second liquid stream obtained after enhancement of the separation. Part of the obtained effluent, especially the second liquid stream, may be recycled to the washing step, to supplement the washing liquid. Since no further washing is required, such dense and compact fuel solids (e.g. pellets) are preferred for their high energy density and ease of transportation. The claimed invention is anticipated by the reference because the reference teaches a composition which comprises all of the claimed components. In the alternative, no patentable distinction is seen to exist between the reference and the claimed invention absent evidence to the contrary. Regarding Claims 2 and 3 Pels further discloses in paragraph 0023, the washing of step (b) preferably takes place in counter-current mode, which may be continuous or in stages. For process efficiency, continuous counter-current washing is preferred. Pels discloses in paragraph 0024, in step (b), water is used to remove the bulk of the remaining ions from the torrefied material obtained in step (a). The washing liquid comprises water or preferably is water. In a preferred embodiment, fresh water is used as washing liquid, such as rainwater, surface water or tap water. Pels discloses in paragraph 0030, a sample of about 100 gram of the thus obtained torrefied EFB was washed three times in different washing fluids at 50 °C. These washing fluids served as model for the composition of the three washing fluids in a 3-staged counter-current washer. The first two were prepared by mixing Torwash liquor with water and the third stage was composed of clean demineralized water. The amount of washing liquid that was used followed from a calculation of washing in three stages where a minimal amount of fresh water was used. Three samples of the material that were washed according to this procedure were pressed into a disk with 65 bar mechanical press to establish the effect of mechanical dewatering. Regarding Claim 8 Pels discloses in paragraph 0014, the liquid to solid (L/S) ratio in the mixture that is subjected to step (a) is preferably in the range of 2 - 25. These L/S ratios takes into account the solids present in the liquid phase (they are classified as solids) as well as the liquid in the solid phase (classified as liquids). Regarding Claims 9 and 18 Pels discloses in paragraph 0010, although any type of biomass feedstock could be used, in one embodiment the process is performed with biomass which benefits from Torwash over regular (dry) torrefaction, including biomass having a high salt content, such as a high potassium and/or chloride content. It is preferred that the effluent stream and the biomass are both residues from the same process. The benefits are largest if the biomass is fibrous in nature and requires substantial amounts of water for the removal of dissolution of salts. Preferred types of biomass in this respect are selected from grass, reeds, hay, straw, leaves, bamboo, sugar beet heads, moss, clippings, garden waste, residues from food industry (e.g. empty fruit bunches (EFB), discarded fresh fruit bunches (FFB), coconut fibres, mesocarp, olive kernels, rice husk). In one embodiment, the process is performed with biomass that is mainly available in areas where fresh water is limitedly available. Suitable biomass includes EFB, coconut fibres, olive kernels, rice husk, palm fronds, sugar cane tops and wood obtained from pruning or chopping trees. The process is particularly advantageous for fibrous biomass, as post- washing of torrefied biomass provides most optimal results. In an especially preferred embodiment, the biomass is fibrous biomass, preferably selected from EFB, discarded FFB, mesocarp, coconut fibres, wood including hardwood and softwood, wood obtained from pruning or chopping trees. The use residues from the palm oil production plants is especially preferred, such as EFB, discarded FFB, partly processed EFB, coconut mesocarp, is especially preferred, because this source of biomass is perfectly compatible with the use of POME, as both are a waste product of palm oil production plants. Regarding Claims 10 and 19 Pels discloses in paragraph 0028, the washed material obtained from step (b) is advantageously further processed into solid fuels. Such further processing may include drying, milling and pelletization. Depending on the total moisture content of the obtained washed material, further drying may be beneficial. Pelletization of the obtained solids, which may include milling, affords fuel pellets which are easy to store and transport. Drying and pelletizing the washed solids in the context of a Torwash process is well- known in the art. Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. Claim(s) 7, 11, 17 and 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Pels et al. (WO 2019/059768 A1) hereinafter “Pels” in view of Krokos et al. (WO 2013/162355 A1). Regarding Claims 7, 11, 17 and 20 Pels discloses the process of claim 1 but fails to further disclose preheating the washing liquid in a heat exchanger. However, it is known in the art to preheat a washing liquid in a heat exchanger that is used in a hydrothermal treatment system, as taught by Krokos. Krokos discloses in paragraph 0001, process for heat treatment of biomass, especially fibrous biomass, to remove salts and other undesired components and to make it suitable as a solid fuel. Krokos discloses in paragraph 0011, a hydrothermal treatment of biomass with the objective to convert it into an attractive fuel. The process combines four improvements that are individually already interesting: dewatering, salt removal, drying and anaerobic digestion. In the process of the invention, biomass is treated in liquid water, so that the salts, as defined below, present in the biomass, go into solution. Moreover, the structure of the biomass can be changed in such a way that it becomes easy to dewater it mechanically. The process is preferentially performed in combination with anaerobic digestion of the effluent. This produces enough biogas to generate the energy to run the process autonomously if desired. Krokos discloses in paragraph 0012, a process for the treatment of biomass comprising: (a) pretreating wet biomass; (b) extracting the pretreated biomass with water at a temperature between ambient temperature and 160°C (at a pressure which keeps water substantially liquid); (c) mechanically dewatering the extracted biomass to produce a dewatered biomass and an aqueous effluent; (g) subjecting the aqueous effluent produced in step (c) to an anaerobic treatment, while keeping the aqueous effluent at temperatures below 160°C. Krokos discloses in paragraph 0018, prior to the heating steps of the process, the biomass can be pretreated in step (a). Such pretreatment may comprise removal of non-biomass such as sand, stones, plastic etc, by sieving or otherwise, shredding, cutting, chopping and/or screening and the like. The pretreatment especially comprises a mechanical pretreatment, which may involve breaking the cell structure of the biomass. This is an important step for allowing access to the cell content of the biomass during the subsequent washing and heat treatments. The mechanical pretreatment preferably comprises chipping, milling, grinding, or extrusion, using choppers, stone mills, ball mills, extruders, or the like. For non-fibrous materials, such as sludges, no extensive mechanical pretreatment is needed. Krokos further discloses in paragraph 0019, the heating or extracting step (b) serves to wash the biomass, especially for extracting water-soluble material, such as salts and hydrophilic organic substances. Step (b) can be performed in different modes. In a preferred embodiment, the heating step is performed at temperatures around 100°C or higher; a temperature above 160° is not desired since it would lead to excessive decomposition of the plant constituents, producing phenols, furfurals, methanol and other unwanted by-products. Heating above 100°C is performed at superatmospheric pressure so as to ensure that water largely remains in the liquid phase allowing water-soluble material, in particular salts, but also that saccharides and other organic components derived from cellulosic and hemi-cellulosic materials, do not undergo undesired reactions and can be extracted from the biomass without substantial derivatization. The reactor can include a heat exchanger, where incoming and outgoing flows exchange heat. The incoming flow is heated from ambient temperature to a level below the reaction temperature. The outgoing flow is cooled from reaction temperature to about 35°C, which is the preferred temperature for digestion in step (g). The reactor also includes a device to raise the temperature of the incoming flow to the desired level. Krokos discloses in paragraph 0022, advantageously, the multiple stages are arranged in such a way that the quality of the extracting water increases with the progressing stages, relatively low quality water being used in a first stage and relatively high quality water being used in a later or last stage. Herein "low quality" and "high quality" primarily relate to temperature and dissolved matter (solutes), the higher the temperature or the lower the solutes level, the higher the quality. In a suitable embodiment, eluate (extract) of a later stage of the multiple extraction step (b) is used in a first step, and condensed steam, having relatively high temperature and low solutes level ("salt-free"), in particular less than 100 ppm of solutes (salts), resulting from the evaporation of water in step (e) is used as liquid water in a last stage of extraction step (b). Similarly water resulting from the dewatering of the extracted biomass in step (c) may be used in a last stage or second last stage of extraction step (b). It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to preheat the washing liquid of Pels in a heat exchanger that is used in a hydrothermal treatment system, as taught by Krokos. The motivation to do so is to pretreat the washing liquid though heating in order to aid in the removal of non-biomass such as sand, stones, plastic etc., and washing the biomass, especially for extracting water-soluble material, aids in the removal of such salts and hydrophilic organic substances. Allowable Subject Matter Claims 4 and 16 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. The applied prior art fails to teach and/or suggest the claimed process further comprising the process according to claim 2, which is performed in a hydrothermal treatment plant wherein at least two hydrothermal reactors perform the process in parallel, and wherein one or more of the intermediate washing effluents and final washing effluent from a first reactor is used as washing liquid in the first washing step or one or more of the intermediate washing steps in a second reactor and the process according to claim 4, wherein the temperature of the washing effluent is kept above 150 °C. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Retsina et al. (US 2015/0167969) discloses in the abstract, a process for producing biomass pellets and fermentable sugars from cellulosic biomass, comprising: extracting cellulosic biomass feedstock with steam and/or hot water to produce an extract liquor containing hemicellulosic oligomers, dissolved lignin, and cellulose-rich solids, wherein at least some of the steam and/or hot water is derived from an internal or external source of fermentation vinasse; separating at least a portion of the hemicellulosic oligomers from the cellulose-rich solids, to produce intermediate solids; hydrotorrefying the intermediate solids to produce the energy-dense biomass, wherein water for hydrotorrefaction is derived, at least in part, from the internal or external source of fermentation vinasse; pelletizing the energy-dense biomass to form biomass pellets; and hydrolyzing the hemicellulosic oligomers into fermentable sugars. Haan et al. (US 2015/0166683) discloses in the abstract, a process for treating a solid cellulosic biomass material for reduction of the content of unwanted inorganic components prior to using the material in the production of a biofuel and/or biochemical, comprising: providing a solid cellulosic biomass material; washing the solid cellulosic biomass material with a stream of water or in a water bath, wherein the water has a temperature in the range from 120° C. to equal to or less than 150° C. at a pressure high enough to maintain water in the liquid phase, to provide washed cellulosic biomass material comprising significantly reduced levels of unwanted inorganic components when compared to the levels in the starting biomass material. Any inquiry concerning this communication or earlier communications from the examiner should be directed to LATOSHA D HINES whose telephone number is (571)270-5551. The examiner can normally be reached Monday thru Friday 9:00 AM - 6:00 PM. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Prem Singh can be reached at 571-272-6381. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /Latosha Hines/Primary Examiner, Art Unit 1771
Read full office action

Prosecution Timeline

Nov 24, 2023
Application Filed
Jan 17, 2026
Non-Final Rejection — §102, §103 (current)

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Prosecution Projections

1-2
Expected OA Rounds
51%
Grant Probability
73%
With Interview (+22.5%)
3y 6m
Median Time to Grant
Low
PTA Risk
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