Application of low-grade waste heat to biomass

Abstract

Disclosed herein is a system and method for producing syngas from the gasification of biomass that uses heat generated during gas compression and recycles this heat to other process streams within the system, such as drying of the biomass. TIFF2025513369000003.tif76161

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 332,559, filed April 19, 2022, which is incorporated by reference in its entirety.

[0002] I. Field TECHNICAL FIELD The present disclosure and related inventions relate at least to the field of renewable fuel production, and more particularly to systems and methods for the gasification of biomass. [Background technology]

[0003] II. Background Due to rapid climate change and projected damages due to global warming, access to clean and environmentally friendly energy has become essential for the sustainable development of the international community. Biomass is one of the important renewable energy resources, as it is energy-rich and is often considered an unwanted waste.

[0004] Biomass is a renewable organic resource that includes, but is not limited to, agricultural and forest residues, specialty crops grown specifically for energy use (such as switchgrass and willow trees), organic solid municipal waste, and animal waste. This renewable resource can be used to produce syngas, along with other by-products, through gasification. Syngas consists primarily of hydrogen, carbon monoxide, and carbon dioxide.

[0005] Biomass gasification is a route to convert biomass into hydrogen and other products using a partial oxidation process that requires heat, steam, and oxygen. Growing biomass removes carbon dioxide from the atmosphere, so net carbon emissions are generally low. Carbon from the process may be captured and stored for utilization.

[0006] Among the various routes available for biomass-based energy production, biomass gasification is one of the most important routes that has been extensively studied. Due to the growing interest in biomass gasification, several energy producers are developing and trying to optimize biomass gasification systems. One of the main problems associated with biomass gasification is efficiency. During biomass gasification, a large amount of energy is produced, but each process unit in a biomass gasification plant is a potential heat loss point. The present invention seeks to overcome these problems and others that are described in detail below. Summary of the Invention

[0007] overview The present invention provides a method for increasing the efficiency of a biomass gasification system by recycling heat generated within the system. The inventors have developed a method for increasing the overall efficiency of a biomass gasification system by recycling heat that would otherwise be lost to the atmosphere. If the gasification plant has a capacity of 350 short tons of biomass per day on an as-fed basis, then approximately 12 GJ / h of heat can be utilized. This degree of heat utilization represents a significant contribution to the plant efficiency.

[0008] In some aspects, methods and / or systems for recycling low-grade waste heat from a biomass gasification process are disclosed. 2 A method and / or system for recycling low-grade waste heat from a capture and storage process is disclosed. 2 Methods and / or systems for recycling low-grade waste heat from liquefaction are disclosed. In some aspects, methods and / or systems for recycling low-grade waste heat from tail gas compression are disclosed. In some aspects, methods and / or systems for recycling low-grade waste heat from syngas compression are disclosed.

[0009] Synthesis gas or syngas is the term used to describe the unprocessed gas produced by the gasification of biomass feedstocks. Syngas contains hydrogen (H 2 ) and carbon monoxide (CO), with carbon dioxide (CO 2 ) and methane (CH 4 )

[0010] In some embodiments, disclosed herein is a method of recycling low-grade waste heat, comprising compressing a gas stream in a compressor to form a compressed gas stream and waste heat, cooling the compressed gas stream by thermally contacting the compressed gas stream with a heat exchanger having a cold air stream therein to heat the cold air stream and generate a warm air stream, and drying the biomass by thermally contacting the biomass with a warm air stream to reduce moisture in the biomass. In some embodiments, the gas stream is carbon dioxide, dihydrogen, syngas, and / or tail gas. In some embodiments, the heat exchanger is recuperative (e.g., indirect, direct, and / or special) and / or regenerative (e.g., static and / or dynamic). In some embodiments, the heat exchanger comprises a radiator. In some embodiments, the air stream that cools the compressed gas stream and the exiting warm air stream are moved by the same mechanical unit (e.g., by a bi-function blower).

[0011] In some embodiments, the biomass to be dried is wetter and / or drier. In some embodiments, the biomass is contained within a biomass feed drying unit and the biomass is dried therein. In some embodiments, the biomass feed drying unit comprises a rotary dryer and / or a direct-heated air dryer. In some embodiments, the biomass in the biomass feed drying unit is dried for about 30 minutes to about 4 hours. In some embodiments, the biomass comprises agricultural crop residues, forest residues, specialty crops grown specifically for energy use, algae, seaweed, organic solid municipal waste, and / or animal waste. In some embodiments, the biomass moisture content is reduced by about 2.5% to 98% (inclusive) relative to the biomass prior to drying. In some embodiments, the biomass moisture content is at least 2.5%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 98% of the biomass before drying. 0%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 98%, or about 2.5%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 98%. In some embodiments, the moisture content of the biomass is normalized to a certain level. In some embodiments, normalization of the biomass moisture level improves process efficiency. In some embodiments, drying the biomass reduces the volume and / or mass of the biomass and / or increases the energy-based throughput of the biomass relative to undried biomass.

[0012] In some embodiments, recycled low-grade waste heat is used to generate a warm air stream. In some embodiments, the warm air stream is exactly 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85°C, or any range derivable therein, and at least 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85°C, or any range derivable therein, 2, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85°C, or any range derivable therein, or about 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85°C, or any range derivable therein. In some embodiments, the warm air stream is about 20-80°C. In some embodiments, the warm air stream is about 50-80°C. In some embodiments, the warm air stream is about 60-70°C. In some embodiments, the warm air stream is combined with high grade thermal energy generated by conventional means or recycled from another waste heat source.

[0013] In some embodiments, the methods and / or systems described herein result in one or more of improved thermal efficiency, increased production rate per unit gas stream feed substrate, reduced power demand, and / or capital savings for facilities including gas stream compressors.

[0014] In some embodiments, disclosed herein is a system for recycling low-grade waste heat, comprising a biomass, a biomass drying unit, a gasification unit, a compressor, waste heat, a heat exchanger, and a heat transfer unit. In some embodiments, the heat transfer unit transfers waste heat recovered from the gas compressor by the heat exchanger to the biomass and / or the biomass drying unit.

[0015] In some embodiments, biomass, a biomass drying unit, a gasification unit, a syngas compression unit, a plurality of water gas shift units, a plurality of pollutant removal units, a CO 2 Removal unit, CO 2 Compressor, tail gas compressor, and / or H 2 Disclosed herein is a system for recycling low-grade waste heat, including a liquefaction unit, waste heat, a heat exchanger, and a heat transfer unit. In some embodiments, the heat transfer unit includes a syngas compression unit, a CO liquefaction ... 2 Compressor, tail gas compressor, and / or H 2 The recovered waste heat from the liquefaction unit is transferred to the biomass and / or biomass drying unit. Throughout this application, the term "about" is used to indicate that a value includes the inherent variation of error for any method of measurement or quantification.

[0016] As used herein, various terminologies are used only for the purpose of describing particular embodiments, and are not intended to limit the embodiments. For example, as used herein, ordinal terms (e.g., "first," "second," "third," etc.) used to modify an element, e.g., a structure, component, operation, etc., do not in themselves indicate any priority or order of the element relative to another element, but rather merely distinguish the element from another element having the same name (absent the use of the ordinal term). The term "coupled" is defined as connected, although not necessarily directly and not necessarily mechanically, and two things that are "coupled" may be integral with each other. The terms "a" and "an" are defined as one or more, unless the disclosure explicitly requires otherwise. The term "substantially" is defined as most of what is specified, but not necessarily entirely (and includes what is specified, e.g., substantially 90 degrees includes 90 degrees, and substantially parallel includes parallel), as will be understood by those skilled in the art. In any disclosed configuration, the term "substantially" may be replaced with "within [a percentage] of" what is specified, where percentages include 0.1, 1, 5, and 10 percent.

[0017] Throughout this application, the term "about" is used to indicate that a value includes the inherent variation of error for a measurement or quantification method. In various embodiments, as used herein, the term "about" refers to including the normal error range for each value, which is easily recognized. Reference to a value or parameter with "about" herein includes (and describes) the embodiment directed to the value or parameter itself. For example, a description that refers to "about X" includes the description of "X". In some embodiments, "about" can refer to ±15%, ±10%, ±5%, or ±1%, as will be understood by those skilled in the art.

[0018] The use of the words "a" or "an" when used in conjunction with the term "comprising" can mean "one," but is also consistent with the meaning of "one or more," "at least one," and "one or more."

[0019] The phrase "and / or" means "and" or "or." By way of example, A, B, and / or C includes A only, B only, C only, a combination of A and B, a combination of A and C, a combination of B and C, or a combination of A, B and C. In other words, "and / or" acts as an inclusive logical OR. Similarly, the phrase "A, B, C, or a combination thereof" or "A, B, C, or any combination thereof" includes A only, B only, C only, A and B, A and C, B and C, or A, B and C.

[0020] The words "comprising" (and any form of comprising, such as "comprise" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "includes" and "include"), or "containing" (and any form of containing, such as "contains" and "contain") are inclusive or open-ended and do not exclude additional unrecited elements or method steps.

[0021] The compositions and methods of their use may "comprise," "consist essentially of," or "consist of" any of the components or steps disclosed throughout this specification. Compositions and methods "consisting essentially of" any of the disclosed components or steps limit the scope of the claims to certain materials or steps that do not substantially affect the basic and novel characteristics of the claimed invention. Any embodiment of any of the systems, methods, apparatus, and articles of manufacture may consist of or essentially consist of, rather than comprise / have / include, any of the described steps, elements, and / or features. Thus, in any claim, the terms "consisting of" or "consisting essentially of" may be substituted for any of the open-ended linking verbs listed above to modify the scope of a given claim from the scope that would result from the use of the open-ended linking verb. Apparatuses, systems, and methods "consisting essentially of" any of the disclosed components, apparatus, or steps limit the scope of the claims to certain materials or steps that do not substantially affect the basic and novel characteristics of the claimed embodiment. Additionally, the term "wherein" may be used interchangeably with "where."

[0022] It is contemplated that any embodiment discussed in this specification can be implemented with respect to any method or composition of the invention, and vice versa. Further, a composition of the invention can be used to achieve a method of the invention.

[0023] Other objects, features, and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and specific examples, while indicating specific embodiments of the present invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. [Brief description of the drawings]

[0024] The following drawings form part of the present specification and are included to further demonstrate certain aspects of the invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein.

[0025] [Figure 1] 1 illustrates a syngas generation process and H2 production plant 111 according to various aspects of the disclosure. Four options for capturing waste heat are shown using any one or more of heat exchangers 75A, 75B, 75C and 75D to capture the waste heat as any one or more of heated streams (76), (77), (78) and (79), where heated stream (76) is formed by recycled waste heat generated during CO2 compression, heated stream (77) is formed by recycled waste heat generated during hydrogen liquefaction, heated stream (78) is formed by recycled waste heat generated during tail gas compression, and heated stream (79) is formed by recycled waste heat from syngas compression. These options can be used alone or in any combination. As shown in FIG. 1, 102 includes biomass, 104 includes a biomass feed preparation system, 103 includes a biomass feed system, 106 includes a gasification system, 108 includes a post-gasification system, 110 includes spent fines and spent bed media, 112 includes a syngas compression system, 114 includes a water gas shift system, 116 includes an H2S removal system, 118 includes a CO2 compression system, 120 includes a CO2 removal system, 122 includes an H2 separation system, 124 includes a power generation system, 126 includes a flue gas, 128 includes a hydrogen liquefaction system, 130 includes a CO2 for sequestration, and 132 includes a tail gas compression system. [Diagram 2] 1 illustrates a syngas production process according to various aspects of the present disclosure. [Diagram 3]Figure 1 illustrates an integrated simulation of the H2-BiCRS process created using Aspen Plus software. The facility's CO2 separation subsystem is shown. Note that chiller 2 is an example of a potential source of low grade heat and blower air. Biomass / syngas / H2 is shown in lines 23, 25, 26, 27, 29, 30, 31, 34, 35, 37, and 38; water / condensate is shown in lines 24, 28, 32, 33, 36, and 39; and CO2 is shown in line 40. TEG stands for thermoelectric generator. [Figure 4] 4 illustrates a syngas cooling unit according to various aspects of the disclosure. As shown in FIG. 4, 302 includes a thermoelectric generator, 304 includes a heat exchanger system, 306 includes a chiller system, 308 includes a flash system, 310 includes an absorber system, 312 includes a chiller system, 314 includes a recycle compressor, 316 includes a flash system, 318 includes a flash system, 320 includes a flash system, 322 includes a compressor system, and 324 includes a circulation pump system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Detailed Description One of the common challenges with biomass gasification systems is the moisture content of the biomass feed. Unprocessed biomass has a naturally high moisture content (e.g., in some embodiments, 50% water by weight), and the higher the water percentage, the lower the thermal efficiency of the system and the lower the heating value of the syngas produced by the gasifier. Furthermore, the feed rate of the gasifier is usually limited by the mass and / or volume of the feed. A drier feed allows for a higher feed throughput on an energy basis, and therefore a higher production rate, e.g., a higher production rate of product hydrogen for the same size gasifier. A related challenge is that the moisture content of biomass is subject to variation depending on the source, climate, and season, while a constant moisture content is desirable for reliable operation of the gasifier and downstream equipment. These and other challenges are described in more detail in Sarah E. Baker et al., "Getting to Neutral - Options for Negative Carbon Emissions in California" (2020), which is incorporated by reference for the purposes described herein.

[0027] One common solution to these challenges is to actively pre-dry the biomass feed using high-grade heat, e.g., from natural gas or from processes elsewhere on-site. However, using high-grade heat in this way is costly, both as fuel and for the other aforementioned uses of process heat, which reduces the benefits of pre-drying the biomass. Furthermore, when producing renewable hydrogen, the use of natural gas can have a negative impact on the environmental profile of the product and may be explicitly rejected.

[0028] Low-grade waste heat (e.g., T<70°C) is common in industrial processes, but dihydrogen (H 2 )Biomass Carbon Removal and Storage (BiCRS) (H 2-BiCRS) for geological CO storage. 2 Compression, syngas compression before water-gas shift, and H 2 The compression and / or liquefaction of H requires intermediate cooling between the compression stages, typically at 40-50°C. Each of these compression stages accounts for a major proportion of the energy loss in the overall system. 2 Current systems for liquefaction are overall thermally inefficient and 2 -This accounts for the majority of the power demand in the proposed BiCRS design.

[0029] Methods and systems for addressing the above problems are disclosed herein. In some embodiments, methods and systems are disclosed for recycling and / or capturing low-grade waste heat from compressor intercooling and other sources. In some embodiments, the captured low-grade waste heat is used for pre-drying biomass. In some embodiments, the captured low-grade waste heat is used instead of or in addition to conventional biomass drying methods (e.g., drying with high-grade heat).

[0030] In some embodiments, methods and / or systems are disclosed that include, consist of, or consist essentially of the following three aspects: (1) active air cooling of the compressed gas stream to produce warm air (e.g., 20-70° C. depending on ambient and / or operating conditions) by an assembly including a radiator and / or heat exchanger; (2) conveying the warm air from the compressor (e.g., including a compression train) to a biomass pre-processing area via a low pressure drop duct structure; and (3) drying of the biomass feed by direct contact with the warm air produced and conveyed in steps 1 and 2.

[0031] In some embodiments, the methods disclosed herein can improve the thermal efficiency of a plant, resulting in higher production rates of products (e.g., better capital utilization of a gasifier) ​​and / or capital savings due to dual-function use of a blower (e.g., a blower that pumps air across a cooling surface is also moving air through biomass drying equipment).

[0032] Drying of biomass with recovered low-grade heat has been studied and piloted (e.g., Dahau et al., 2020; which is incorporated herein by reference for purposes described herein), but the processes described therein focus on heat recovery from the power cycle. In some embodiments, the methods and systems described herein do not include heat recovery from the power cycle. In some embodiments, a key innovation described herein is the integration of compressor intercooling with drying of biomass. In some embodiments, this is particularly true for H 2 In some embodiments, the present disclosure provides a method for the preparation of a biofuel-based fuel cell using syngas and CO 2 As applied to compressors, it applies to any BiCRS pathway and not strictly to hydrogen production. In some embodiments, the present disclosure applies to the H 2 When applied to the compressor, it applies to any system for the conversion of solid biomass to hydrogen and is strictly CO 2 This does not apply to cases involving the capture of

[0033] In some embodiments, the biomass drying methods and / or systems described herein can use conventional configurations, such as, but not limited to, rotary dryers or other types of directly heated air dryers. In some embodiments, drying biomass using the methods and / or systems described herein differs from conventional designs, particularly in the residence time of the biomass in the biomass drying unit. For example, typical biomass residence times for conventional biomass dryers (e.g., biomass drying units) based on high-grade heat are about 1-10 minutes. In contrast, biomass residence times in the present application are generally longer. For example, in some embodiments, biomass residence times are 0.5 hours to 4 hours, which facilitates more efficient use of cooler air.

[0034] In some embodiments, the biomass residence time is exactly 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 8 35, 240, 245, 250, 255, 260, 265, 270, 275, 280, 285, 290, 295, 300 minutes, or any range derivable therein, and at least 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175 ... 5, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250, 255, 260, 265, 270, 275, 280, 285, 290, 295, 300 minutes, or any range derivable therein, or about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 , 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250, 255, 260, 265, 270, 275, 280, 285, 290, 295, 300 minutes, or any range derivable therein.

[0035] In some embodiments, the biomass is exactly 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, 41 wt%, 42 wt%, 43 wt%, 44 wt%, 45 wt%, 46 wt%, 47 wt%, 48 wt%, 49 wt%, 50 wt%, or any range of weight percentages derivable therefrom, at least 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, 41 wt%, 42 wt%, 43 wt%, 44 wt%, 45 wt%, 46 wt%, 47 wt%, 48 wt%, 49 wt%, 50 wt%, or any range of weight percentages derivable therefrom, or about 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, 41 wt%, 42 wt%, 43 wt%, 44 wt%, 45 wt%, 46 wt%, 47 wt%, 48 wt%, 49 wt%, 50 wt%, or any range of weight percentages derivable therefrom.In some embodiments, the biomass has a starting moisture content of about 17.2% to about 10% by weight water. In some embodiments, the biomass moisture content is at least exactly 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 100%, or any range derivable therein, or at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 100%, or any range derivable therein. %, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 100%, or any range derivable therein, or about 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 100%, or any range derivable therein. In some embodiments, the moisture content of the biomass is normalized to a constant level. In some embodiments, the moisture content of the biomass is determined to be at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, or any range of weight percent derivable therein, including at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, or any range of weight percent derivable therein. %, 12% by mass, 13% by mass, 14% by mass, 15% by mass, 16% by mass, 17% by mass, 18% by mass, 19% by mass, 20% by mass, 21% by mass, 22% by mass, 23% by mass, 24% by mass, 25% by mass, or any range derivable therein, or about 1% by mass, 2% by mass, 3 Mass%, 4% by mass, 5% by mass, 6% by mass, 7% by mass, 8% by mass, 9% by mass, 10% by mass, 11% by mass, 12% by mass, 13% by mass, 14% by mass, 15% by mass, 16% by mass, 17% by mass, 18% by mass, 19% by mass, 20% by mass, 21% by mass, 22% by mass, 23% by mass, 24% by mass, 25% by mass,Or normalized to any range of mass percent that can be derived therein.

[0036] In some embodiments, recycled low-grade waste heat is used to generate a warm air stream. In some embodiments, the warm air stream is exactly 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85°C, or any range derivable therein, and at least 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85°C, or any range derivable therein, 2, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85°C, or any range derivable therein, or about 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85°C, or any range derivable therein.

[0037] Referring to Figures 1 and 2, biomass is gasified to produce waste CO 2 ultimately producing synthesis gas (syngas) and / or H 2FIG. 3 shows a synthetic gas (syngas) production process using a syngas production system to produce and recover biomass, syngas, and / or H. 2 CO is being supplied 2 1 illustrates a compression system.

[0038] The syngas production process begins with the preparation of a biomass feed that is utilized to produce syngas. The biomass may include, but is not limited to, one or more of the following: forest biomass, such as branches from forest management, brushwood, sawmill residues, or shrubs and chaparral, agricultural residues, such as, but not limited to, almond shells, orchard prunings, low moisture agricultural residues, urban waste, such as, but not limited to, dry solid urban waste, construction timber, green waste, etc. Alternatively, the biomass may be derived from crops, such as sawgrass, that are specifically grown for use as biomass.

[0039] FIG. 1 illustrates a syngas production process, optionally using tail gas as fuel for tar removal, according to various embodiments of the disclosure. Additionally, FIG. 1 illustrates several methods for capturing low-grade waste heat, as described herein. Four options are shown for capturing and recycling the waste heat, for example, but not limited to, to a feed system 103 including biomass 102 and a feed preparation system 104. In certain embodiments, the waste heat can be captured using any one or more of heat exchangers 75A, 75B, 75C, and / or 75D to capture the waste heat as any one or more of heated streams (76), (77), (78), and / or (79), where heated stream (76) is recycled CO 2Heated stream (77) is formed from recycled waste heat generated during compression, heated stream (78) is formed from recycled waste heat generated during tail gas compression, and heated stream (79) is formed from recycled waste heat from syngas compression.

[0040] In various embodiments, the syngas production process 111 includes a block feed system 103 that includes preparation 102 of biomass feed for feeding 104 into a gasifier for gasification 106 of the biomass feed to produce syngas. The gasification process 106 also includes cyclones, tar removal, syngas cooling, syngas filtration, syngas scrubbing, etc., as well as processing and removal 110 of spent wet materials, spent dry materials, spent bed media, etc. Discussions related to biomass feed preparation 102, feeding 104 of biomass to the gasifier, gasification of biomass 106, post-gasification processes 108, and processing and removal 110 of spent materials are provided with reference to FIG. 2 that includes more detailed information of the described processes. In various embodiments, the biomass feed preparation process 102 and biomass supply 104 of FIG. 1 are performed by the biomass supply system 10 and bed media supply system 20 of FIG. 2, the gasification 106 of FIG. 1 are performed by the gasifier and cyclone 30 of FIG. 2, the tar removal system 60, syngas cooler 70, syngas filter 80, and syngas scrubber 90 of FIG. 2, and the treatment and removal process 110 of FIG. 1 are performed by the spent wet fines removal system 50, spent dry fines removal system 100, and spent bed media removal system 40 of FIG. 2.

[0041] 2 illustrates a syngas production process according to various embodiments of the present disclosure. In various embodiments, the syngas production system 222 includes a biomass feed system 10 that includes one or more lock hopper-style feed lines that feed biomass (e.g., dry biomass 1) to the gasifier 30. Multiple feed lines can be arranged in parallel, one or more of which can be designed to supply biomass at a capacity even higher than the intake capacity of the gasifier 30 (e.g., for a system with a capacity of about 350 sTPD, one or more feed lines can each supply biomass at a capacity of about 114% of the total 350 sTPD of feedstock, or about 40 sTPD per feed train). In some embodiments, multiple parallel feed lines of sufficient capacity improve the reliability of the syngas production system 222 when one feed line is disconnected for maintenance.

[0042] In some aspects, the biomass feed is transported to the gasifier and cyclone 30 via a flight chain conveyor. The biomass feed system 10 may include a biomass distribution screw conveyor located on top of the biomass feed system 10 for delivering the biomass to the gasifier and cyclone 30. In some aspects, the biomass is dumped from the biomass distribution screw conveyor into a biomass storage silo, which is purged with nitrogen to prevent dust explosions and self-ignition of the dry fuel. The fuel is transferred from the storage silo through a biomass storage silo discharger and a biomass distribution screw into one or more (e.g., two) lock hoppers, where the pressure of the biomass feedstock is alternately raised from atmospheric pressure to system pressure with carbon dioxide. The fuel is then dumped into a biomass surge hopper, as described below, and depressurized to begin the loading process. Biomass is fed from the pressurized lock hopper through a lock hopper discharger to a biomass surge hopper with a live bottom screw. Biomass is fed from the surge hopper through a metering screw conveyor to a biomass feed screw conveyor which feeds the biomass into the gasifier 30.

[0043] The syngas production process 222 also includes a bed media feed system 20 for feeding bed media to the gasifier and cyclone 30. In some aspects, the bed media includes dolomite, kaolin, olivine, muscovite, sand, limestone, or combinations thereof. In some aspects, the bed media feed system is a single bed media feed rock hopper system. In some aspects, the lock hopper system includes a lock / surge hopper for pressurizing the bed media to system pressure with nitrogen. In some aspects, the bed media feed system includes a bypass screw conveyor for feeding the bed media to the gasifier.

[0044] In various aspects, the syngas production system 222 includes a gasifier 30 designed or configured to gasify the biomass feed received from the biomass supply system 10. In various aspects, the gasifier 30 includes a natural gas fueled start-up heater used to heat the gasifier reactor during start-up of the gasifier reactor. In some aspects, the gasifier reactor may be designed to process biomass at a rate ranging from about 10,000 to about 15,000 kg / h of biomass. In some embodiments, the gasifier reactor may be designed to process biomass at a rate of about 13,230 kg / h of biomass at about 17% moisture by weight. In some embodiments, the gasifier reactor may be designed to process biomass at a rate of about 10,000 kg / h to about 50,000 kg / h of biomass, including any range derivable therein. In some embodiments, the gasifier reactor may be designed to process biomass at a rate of about 25,000 kg / h to about 40,000 kg / h of biomass (including any range derivable therein). In some embodiments, the gasifier reactor may be designed to process biomass at a rate of about 39,000 to about 40,000 kg / h of biomass (including any range derivable therein).

[0045] In some aspects, the gasifier reactor may be designed to process biomass having a moisture content of about 10% to about 25%. In some aspects, the gasifier reactor may be designed to process biomass having a moisture content of about 10% to about 20%. In some aspects, the gasifier reactor may be designed to process biomass having a moisture content of about 8% to about 12%. In some aspects, the gasifier reactor may be designed to process biomass having a moisture content of about 10%.

[0046] At start-up, air for the combustion of biomass is provided by a start-up air system (eg, outside the study battery limits) that includes an air compressor and an air reservoir.

[0047] In some aspects, the biomass feed is gasified in the presence of oxygen and superheated steam by the gasifier 30. In some aspects, the gasifier is any suitable type of gasifier, such as, but not limited to, a refractory-lined pressurized bubbling fluidized bed pressure vessel. In some aspects, oxygen and steam are introduced into the gasifier 30 at multiple locations through a valve mechanism. In some aspects, the oxygen is preheated to a temperature of about 150° C. to about 200° C., preferably to about 175° C. in an oxygen preheater. In some embodiments, the biomass is devolatilized in the gasifier 30 and at least a portion of the char is gasified and at least a portion of the char is combusted to maintain a desired gasification temperature. In some aspects, the syngas produced exits the gasifier 30 at the top of the reactor. In some aspects, entrained dust is at least partially removed from the hot gas in a cyclone and returned to the reactor fluidized bed via a cyclone return pipe (eg, a dipleg).

[0048] After the syngas is produced in the gasifier and cyclone 30, it is fed to a tar removal system 60 for removing tar from the syngas. The syngas may still include melted solids, residual particulate matter, and char. In some aspects, the tar removal system 60 includes a high temperature oxy-combustor (HOB) that converts tar components and other hydrocarbon compounds into hydrogen and carbon monoxide. In the tar removal system 60, fuel gas enters the high temperature oxy-combustor where tar components and other unsaturated hydrocarbon compounds are converted into hydrogen and carbon monoxide. Reducing or eliminating heavier hydrocarbons helps prevent their condensation in downstream equipment. Oxidation temperatures are achieved by injecting oxygen and fuel gas into the tar removal combustor. In some aspects, the tar removal system 60 utilizes recycled syngas that was compressed for fuel downstream of the gasifier and cyclone 30. In some aspects, about 4% to about 14% of the syngas may be recycled or provided to the tar removal system 60 to serve as fuel to operate the tar removal system 60. In some embodiments, the tail gas may be utilized or provided to the tar removal system to act as fuel gas to operate the tar removal system. Both the syngas and the molten solids flow downward through the tar removal vessel and into the syngas cooler 70.

[0049] In some aspects, the syngas production process 222 includes a syngas cooler 70. In some aspects, the syngas cooler cools the syngas to a temperature ranging from about 500° C. to about 570° C., preferably from about 530° C. to about 550° C. In some aspects, the syngas cooler cools the syngas to a temperature of about 540° C. In some aspects, the syngas cooler includes a boiler, a superheater, and a steam drum. In some aspects, boiler feed water is sent to the steam drum of the syngas cooler 70 where it is preheated by low pressure steam coils. In some aspects, the spent fines are separated from the gas stream and fall by gravity into the water bath. In some aspects, the cooled spent wet fines are then sent to the spent wet fines removal system 50 of the syngas production system 222. In some aspects, the heat recovered from the syngas cooler is used to heat the boiler feed water to generate superheated steam. In some aspects, superheated steam is generated using heat recovered from the syngas cooler. In some aspects, the superheated steam is generated at a temperature ranging from about 270° C. to about 310° C. In some aspects, the superheated steam is generated at a temperature ranging from about 288° C. In some aspects, the superheated steam is generated at a pressure ranging from about 30 barg to about 50 barg. In some aspects, the superheated steam is generated at a pressure of about 41 barg. In some aspects, the superheated steam is utilized by integrating with another process stream, the syngas generation process 111. In some aspects, the syngas exiting the syngas cooler 70 is further cooled to about 300° C. by boiler feed water (BFW) spray before being sent to the syngas filter 80.

[0050] In some aspects, heat is recovered from the syngas exiting the syngas cooler by heat exchanger 260 (FIG. 4). In some aspects, the heat recovered by the heat recovery unit is used to generate a secondary steam stream 270 (FIG. 4). In some aspects, the heat recovered by heat exchanger 260 is utilized by integrating with another process stream, syngas production process 222. In some aspects, heat recovery using heat exchanger 260 is performed as an alternative to cooling by BFW spray. In some aspects, the heat recovered from the syngas cooler is used to generate superheated steam.

[0051] In some aspects, the syngas cooled by the syngas cooler is then sent to a syngas filter 80. In some aspects, the syngas exiting the syngas cooler is at a temperature ranging from about 250° C. to about 350° C. In some aspects, the syngas exiting the syngas cooler is at a temperature of about 300° C. In some aspects, the syngas cooled by the quench water stream is then sent to a syngas filter 80. In some aspects, the syngas cooled by the quench water stream is at a temperature ranging from about 250° C. to about 350° C. In some aspects, the syngas cooled by the quench water stream is at a temperature of about 300° C.

[0052] In some aspects, the syngas filter 80 is configured to receive the syngas and spent fines from the syngas cooler 70. In some aspects, the syngas filter is a candle filter unit including metal candle filter elements arranged in a cluster and attached to a tubesheet. In some aspects, the filter candles are cleaned by back pulsing with carbon dioxide from a blowback tank. In some aspects, the filter unit is operated at system pressure and the pulsing gas is injected at an elevated temperature.

[0053] In some aspects, the syngas generation system 222 includes a syngas scrubber 90 configured to receive the syngas from the syngas filter 80 and further cool the syngas to a temperature in the range of about 30° C. to about 60° C. In some aspects, the syngas scrubber 90 cools the syngas to a temperature of about 45° C. In some aspects, the syngas scrubber 90 removes some of the water vapor and residual contaminants from the syngas to protect the syngas compression system and downstream chemical processes from solid contamination in the event of a malfunction of the high-temperature oxygen combustor or the syngas filter 80. In some aspects, the syngas scrubber 90 has an inlet quench system in which water is injected by a cooling pump through a nozzle into the syngas feed stream just before entering the scrubber. In some aspects, the gas is then further cooled through a first stage bed. In some aspects, the scrubber water is circulated by a circulation pump through a heat recovery heat exchanger to the top of the first stage bed. The gas passes through the second stage bed in the second stage and is cooled by recycled water. In some aspects, a process condensate stream is injected into the top of the syngas scrubber 90 to allow for further chloride removal. In some aspects, chemicals are added to the scrubber water to adjust the pH value of the water, to increase chloride removal, and / or to neutralize ammonia from the syngas. In some embodiments, the syngas from the syngas scrubber is fed to a syngas compression system 95. In certain embodiments, the syngas compression system is coupled with a heat exchanger 75 such that waste heat generated during syngas compression is captured and recycled for use elsewhere in the system (e.g., drying biomass) 79.

[0054] In some aspects, the syngas production system 222 includes a solids removal system including a spent bed medium removal system 40 and a spent dry fines removal system 100. In some aspects, the spent bed medium removal system 40 is configured to remove the spent bed medium from the gasifier 30. In some aspects, the spent dry fines removal system 100 is configured to remove the spent dry fines from the syngas filter 80. In some aspects, the solids removal system is configured to store the removed solids. For example, the solids removal systems 40 and 100 may include two separate solids removal systems including a lock hopper, a conveyor hopper, and a storage silo designed to process solid material from the gasifier 30 and the syngas filter 80. In some aspects, the spent bed medium is removed through the bottom of the gasifier 30 to a nitrogen pressurized lock hopper using a water-cooled screw. In some aspects, the spent bed media is pneumatically conveyed through a gasifier spent bed media conveyor hopper to a common gasifier spent bed media silo by using nitrogen or any other available inert gas. In some aspects, the spent dry fines from the syngas filter is removed using a water cooled screw and passes through a lock and conveyor hopper. In some aspects, a buffer hopper located after the cooling screw allows for continuous operation of the screw. In some aspects, the spent dry fines from the syngas filter 80 is loaded into a spent dry fines storage silo by using nitrogen or any other available dry inert gas.

[0055] In various embodiments, the syngas production system 222 also includes a spent wet removal system 50 configured to receive the spent wet fines that drop into the syngas cooler water bath. In some aspects, water from this system is recycled by a pump back into the water in the syngas cooler. In some aspects, the accumulated spent wet fines are cooled, depressurized, and removed from the spent wet removal system 50.

[0056] In various aspects, the nitrogen, carbon dioxide, water, etc. used by the syngas generation system 222 to generate syngas may be provided by auxiliary systems coupled to the syngas generation system 222. For example, the auxiliary systems may include a nitrogen supply system, a carbon dioxide supply system, a water supply system, etc. The auxiliary systems may also include one or more heat exchange systems. For example, the nitrogen supply system may provide nitrogen that may be used in the syngas generation system 222 as an inert gas and as a fuel diluent for the high temperature oxygen combustor during start-up. In some aspects, the nitrogen may be supplied to the project at various pressures, e.g., nitrogen may be supplied at a higher pressure to one component of the syngas generation system and nitrogen may be supplied at a lower pressure to a different component of the syngas generation system. In some aspects, a unique buffer drum is used at each nitrogen pressure to ensure that adequate nitrogen is available for safe operation, start-up and shutdown of the unit. In some aspects, the nitrogen from the buffer drums may flow to low and high pressure nitrogen headers that distribute the nitrogen to the nitrogen consumption points.

[0057] In some aspects, the carbon dioxide supply system supplies sulfur-free CO from the acid gas removal unit to the syngas production system 222. 2 In some aspects, this CO 2 The stream is fed into specific high and low pressure buffering drums in a carbon dioxide supply system. 2 From these drums, the raw syngas is distributed to various components within the syngas production system 222.

[0058] In some aspects, the water supply system includes a high pressure cooling water system and a high pressure seal water system. In some aspects, the high pressure cooling water system is used to cool the spent bed media at the bottom of the gasifier, the spent dry fines, and the biomass feed screw. In some aspects, the cooling water system is a closed loop system operated at high pressure. In some aspects, the loop includes a circulation pump, a storage drum, and a cooling heat exchanger. In some aspects, the high pressure seal water system is used to supply water to the solids removal system and the mechanical seal of the biomass feed screw shaft. In some aspects, the loop includes a circulation pump, a storage drum, and a cooling heat exchanger.

[0059] In some aspects, the auxiliary systems heat exchange system is a high temperature process heat exchange system that includes a high temperature process cooling water system that is a closed loop system and uses a series of pumps, storage drums, and heat exchangers to exchange heat between portions of the facility. In some aspects, the high temperature process water supply cools the scrubber bottoms stream and the high pressure cooling water loop water, and the heated process water can then be used as a heat source for drying the biomass feed, if desired.

[0060] Referring again to FIG. 4, in various aspects, the syngas cooler 211 includes a syngas feed 210. In some aspects, the syngas feed includes hot syngas from a tar removal unit (not shown). The syngas from the tar removal unit may be at a temperature in the range of about 750° C. to about 950° C. Boiler feedwater 220 is provided to the syngas cooler 211 and to a heat exchanger 260. A portion of the boiler feedwater 220 provided to the syngas cooler 211 is heated by the hot syngas in the syngas cooler and converted to superheated steam 250. The superheated steam 250 is at a temperature in the range of about 270° C. to about 310° C. and at a pressure in the range of about 30 barg to about 50 barg. The temperature of the syngas is reduced to a temperature in the range of about 500° C. to about 570° C. after passing through the syngas cooler 211. The cooled syngas then proceeds to a secondary heat exchanger 260 where heat is absorbed from the syngas and the syngas is further cooled to provide a cooled syngas 230 at a temperature in the range of about 250° C. to about 350° C. Spent fines 240 from the syngas are recovered as a stream exiting the bottom portion of the syngas cooler 211. The heat exchanger 260 can be used to transfer heat to the boiler feedwater 220 to generate a secondary steam stream 270. Heat from the secondary steam stream 270 can be utilized by being integrated with another process stream in the syngas production process 222 (FIG. 2).

[0061] 1, in various embodiments, the tar removal system 60 can optionally use tail gas produced as a by-product of the post-gasification process 108 as fuel for the removal of tars from the syngas. For example, as shown in FIG. 1, the syngas resulting from gasification 106 can be compressed and subjected to an aqueous shift process (e.g., a multi-stage aqueous shift process). The syngas can be further compressed (e.g., by pressure swing adsorption) to produce H 2 S, CO 2 , and H 2The tail gas is processed to remove tars, resulting in a tail gas by-product. In various embodiments, these tail gas by-products can be recycled or provided to a tar removal system for use as fuel in the tar removal process within gasification 106. In some cases, the tail gas may be compressed before being sent to the tar removal system. That is, in addition to or instead of using the tail gas for power generation and fueling the boiler, the tail gas may be provided to the tar removal system 60 (FIG. 2) so that the tar removal system 60 can operate using the tail gas by-products as fuel so that the tars in the syngas produced by the syngas production system 222 can be removed or reduced. In some cases, the recycled syngas may also be used as fuel to drive the tar removal system 60. In some cases, the recycled syngas may not be used as fuel, but instead, the recycled tail gas may be used as fuel for the tar removal system 60 to remove tars from the syngas. In certain embodiments, the tail gas compression system is coupled with a heat exchanger 75 such that waste heat generated during tail gas compression is captured and recycled 77 for use elsewhere in the system (e.g., drying of biomass).

[0062] In some embodiments, the methods and systems described herein can be utilized to improve capital efficiency and / or product yield. Information regarding capital efficiency and / or product yield and methods for determining them can be found in Sarah E. Baker et al., "Getting to Neutral - Options for Negative Carbon Emissions in California" (2020), which is incorporated herein by reference for the purposes described herein.

[0063] aspect The following aspects describe particular inventions disclosed herein.

[0064] Aspect 1) compressing the gas stream in a compressor to form a compressed gas stream and waste heat; cooling the compressed gas stream by thermally contacting the compressed gas stream with a heat exchanger having the cold air stream therein so as to heat the cold air stream and produce a warm air stream; and drying the biomass by thermally contacting the biomass with the warm air stream to reduce moisture in the biomass. A method for recycling low-grade waste heat, comprising:

[0065] Aspect 2) The method of aspect 1, wherein the gas stream is carbon dioxide.

[0066] Aspect 3) The method of aspect 1, wherein the gas stream is dihydrogen.

[0067] Aspect 4) The method of aspect 1, wherein the gas stream is a syngas.

[0068] Aspect 5) The method of aspect 1, wherein the gas stream is a tail gas.

[0069] Aspect 6) The method of any one of Aspects 1 to 5, wherein the heat exchanger comprises a radiator.

[0070] Aspect 7) The method of any one of aspects 1 to 6, wherein the cooling of the compressed gas stream and the conveying of the warm air stream are performed by a bi-function blower.

[0071] Aspect 8) The method of any one of aspects 1 to 7, wherein the biomass comprises wetter biomass and / or drier biomass.

[0072] Aspect 9) The method of any one of aspects 1 to 8, wherein the biomass is contained within a biomass feed drying unit and the biomass is dried.

[0073] Aspect 10) The method of aspect 9, wherein the biomass feed drying unit comprises a rotary dryer and / or a direct heated air dryer.

[0074] Aspect 11) The method of aspect 9 or 10, wherein the biomass in the biomass feed drying unit is dried for about 30 minutes to about 4 hours.

[0075] Aspect 12) The method of any one of aspects 1 to 11, wherein the biomass comprises agricultural crop residues, forest residues, specialty crops grown specifically for energy use, organic solid municipal waste, and / or animal waste.

[0076] Aspect 13) The method of any one of aspects 9-12, wherein the biomass moisture content is reduced by 2.5% to 98%, inclusive.

[0077] Aspect 14) The method of aspect 13, wherein the biomass moisture content is reduced by about 2.5%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 98%.

[0078] Aspect 15) The method of aspect 13 or 14, wherein the moisture content of the biomass is normalized to a constant level.

[0079] Aspect 16) The method of any one of aspects 9 to 15, wherein drying the biomass reduces the volume and / or mass of the biomass and / or increases the energy-based throughput of the biomass relative to undried biomass.

[0080] Aspect 17) The method of any one of aspects 1 to 16, wherein the warm air stream is about 20 to 80° C.

[0081] Aspect 18) The method of any one of aspects 1 to 17, wherein the warm air stream is about 50-80° C.

[0082] Aspect 19) The method of any one of aspects 1 to 18, wherein the warm air stream is about 60-70° C.

[0083] Aspect 20) The method of any one of aspects 1 to 19, wherein the warm air stream is combined with high-grade thermal energy generated by conventional means.

[0084] Aspect 21) The method of any one of aspects 1-20, resulting in one or more of improved thermal efficiency, increased production rate per unit gas stream feed substrate, reduced electricity demand, and / or capital savings for facilities including the gas stream compressor.

[0085] Aspect 22) A system for recycling low-grade waste heat, comprising: a biomass, a biomass drying unit, a gasification unit, a compressor, waste heat, a heat exchanger, and a heat transfer unit, The system, wherein the heat transfer unit transfers waste heat recovered by the heat exchanger from the gas compressor to the biomass and / or biomass drying unit.

[0086] Aspect 23) The system comprises biomass, a biomass drying unit, a gasification unit, a syngas compression unit, a plurality of water gas shift units, a plurality of pollutant removal units, a CO 2 Removal unit, CO 2 Compressor, tail gas compressor, and / or H 2 The liquefaction unit, the waste heat, the heat exchanger, and the heat transfer unit are included; The heat transfer unit is connected to the syngas compression unit, the CO2 compressor, and / or the H 2 Aspect 23. The system of aspect 22, wherein waste heat recovered from the liquefaction unit is transferred to the biomass and / or biomass drying unit. EXAMPLES

[0087] The following examples are included to demonstrate preferred embodiments of the invention. Those skilled in the art should recognize that the techniques disclosed in the following examples represent techniques discovered by the inventors to function well in the practice of the invention, and therefore can be considered to constitute preferred modes for its practice. However, those skilled in the art should recognize, in light of this disclosure, that many changes can be made to the specific embodiments disclosed and still obtain the same or similar results, without departing from the spirit and scope of the invention.

[0088] Example 1 To investigate the benefits of cold gas recycling, we used Aspen Plus software to 2 -An integrated simulation of the BiCRS process was performed. 2 A separation subsystem is shown where chiller 2 is an example of a potential source for capture and recycling of low grade heat and blower air.

[0089] The inventors have estimated that application of the methods disclosed herein can substantially reduce the moisture content of the input biomass. For example, consider the case where the raw moisture content is reduced from a baseline of 17.2% water by weight to 10% water by weight. The results of the two scenarios are shown in Table 1 below. Drying the biomass allows for approximately 9% higher facility productivity and slightly increases the gasifier cold gas efficiency (on a higher heating value basis).

[0090] (Table 1)H 2 -BiCRS process simulation results TIFF2025513369000002.tif27160

[0091] All of the methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. Although the compositions and methods of the present invention have been described with reference to preferred embodiments, it will be apparent to those skilled in the art that modifications may be made to the methods described herein and in the steps or in the sequence of steps of the methods without departing from the concept, spirit and scope of the invention. More specifically, it will be apparent that certain agents that are both chemically and physiologically related may be substituted for the agents described herein and still achieve the same or similar results. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims.

Claims

1. compressing the gas stream in a compressor to form a compressed gas stream and waste heat; cooling the compressed gas stream by thermally contacting the compressed gas stream with a heat exchanger having the cold air stream therein so as to heat the cold air stream and produce a warm air stream; drying the biomass by thermally contacting the biomass with the warm air stream to reduce moisture in the biomass. A method for recycling low-grade waste heat, comprising:

2. 10. The method of claim 1, wherein the gas stream is carbon dioxide.

3. 2. The method of claim 1, wherein the gas stream is dihydrogen.

4. The method of claim 1 , wherein the gas stream is a syngas.

5. The method of claim 1 , wherein the gas stream is a tail gas.

6. The method of claim 1 , wherein the heat exchanger comprises a radiator.

7. 2. The method of claim 1, wherein the cooling of the compressed gas stream and the transport of the warm air stream are accomplished by a bi-function blower.

8. 2. The method of claim 1, wherein the biomass comprises wetter biomass and / or drier biomass.

9. 10. The method of claim 1, wherein the biomass is contained within a biomass feed drying unit and the biomass is dried.

10. 10. The method of claim 9, wherein the biomass feed drying unit comprises a rotary dryer and / or a direct heated air dryer.

11. 10. The method of claim 9, wherein the biomass in the biomass feed drying unit is dried for between about 30 minutes and about 4 hours.

12. 10. The method of claim 1, wherein the biomass comprises agricultural crop residues, forest residues, algae, seaweed, specialty crops grown specifically for energy utilization, organic solid municipal waste, and / or animal waste.

13. 13. The method of claim 1, wherein the biomass moisture content is reduced by about 2.5% to about 98%, inclusive.

14. 14. The method of claim 13, wherein the biomass moisture content is reduced by about 2.5%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 98%.

15. 14. The method of claim 13, wherein the moisture content of the biomass is normalized to a constant level.

16. 10. The method of claim 1, wherein drying the biomass reduces the volume and / or mass of the biomass and / or increases the energy-based throughput of the biomass relative to undried biomass.

17. 2. The method of claim 1, wherein the warm air stream is at about 20-80°C.

18. 2. The method of claim 1, wherein the warm air stream is at about 50-80°C.

19. 2. The method of claim 1, wherein the warm air stream is at about 60-70°C.

20. 10. The method of claim 1, wherein the warm air stream is combined with high grade thermal energy generated by conventional means.

21. 10. The method of claim 1, resulting in one or more of improved thermal efficiency, increased production rate per unit gas stream feed substrate, reduced power demand, and / or capital savings for facilities including gas stream compressors.

22. A system for recycling low-grade waste heat, comprising: a biomass, a biomass drying unit, a gasification unit, a compressor, waste heat, a heat exchanger, and a heat transfer unit, The system, wherein the heat transfer unit transfers waste heat recovered by the heat exchanger from a gas compressor to the biomass and / or biomass drying unit.

23. The system includes biomass, a biomass drying unit, a gasification unit, a syngas compression unit, a plurality of water gas shift units, a plurality of pollutant removal units, a CO 2 Removal unit, CO 2 Compressor, tail gas compressor, and / or H 2 The liquefaction unit, the waste heat, the heat exchanger, and the heat transfer unit are included; The heat transfer unit is connected to the syngas compression unit, the CO2 compressor, and / or the H 2 23. The system of claim 22, wherein waste heat recovered from the liquefaction unit is transferred to the biomass and / or biomass drying unit.

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