Method for cellulose ethanol production coproducts workup and applications

Abstract

The present application relates to the field of cellulose ethanol production by-product post-processing, and discloses a cellulose ethanol production by-product post-processing method and application, the method comprising: the filtrate obtained by solid-liquid separation of cellulose ethanol production by-products is concentrated by evaporation to obtain thick slurry and clear liquid, and the thick slurry is mixed with the filter residue obtained by solid-liquid separation for blending combustion; wherein the mass ratio of thick slurry to filter residue for blending combustion is 1:2-7. The cellulose ethanol production by-product post-processing method does not need to perform sewage treatment on the filtrate after solid-liquid separation of by-products, and has high energy utilization rate, and by controlling the blending combustion ratio of thick slurry to filter residue, the phenomenon of thick slurry and filter residue agglomerating and coking during combustion in the boiler is avoided, so that the boiler can stably combust.

Description

Technical Field

[0001] This invention relates to the field of post-processing of by-products from cellulosic ethanol production, and more specifically, to methods and applications for post-processing of by-products from cellulosic ethanol production. Background Technology

[0002] Cellulose ethanol uses straw as raw material. The main components of straw are cellulose, hemicellulose, lignin and ash. Most of the effective components for producing ethanol, cellulose and hemicellulose, are utilized in the production process. The waste by-products of cellulose ethanol production contain a lot of lignin (90% insoluble lignin and 10% soluble lignin), a small amount of cellulose and hemicellulose, soluble polysaccharides and a large amount of water.

[0003] Existing technologies typically involve solid-liquid separation of byproducts. The obtained solids are generally used as boiler fuel, while the filtrate is diluted with a large amount of water (usually by a factor of 10) to reduce the concentration of COD and various ions to levels that can be handled by conventional wastewater treatment processes before being sent to the sewage treatment system. This method results in high investment costs for the wastewater treatment system, ineffective utilization of the effective components in the filtrate, and high concentrations of COD, sulfate, and ammonia nitrogen in the wastewater generated from the waste mash, making it extremely difficult to treat using conventional sewage treatment processes.

[0004] Biomass fuels are very versatile; any photosynthetically processed, unused woody materials can be used, such as rice husks, sunflower seed husks, sorghum stalks, corn stalks, and bean stalks. These fuels are characterized by relatively low calorific value, low density, large particle size, high moisture content, and high volatile matter content. They also contain a lot of impurities such as stones and soil, and are prone to clumping when wet. Due to these characteristics and the nature of their supply and demand, the blending quantity and proportion of different biomass fuels vary greatly during combustion, significantly impacting stable boiler combustion. These characteristics dictate that specially processed biomass fuels are expensive, while unprocessed biomass fuels are unsafe and uneconomical to store and transport. Furthermore, boilers using any type of biomass feedstock require a feed preparation system and a large raw material storage area, thus increasing the operating costs for businesses. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of difficult treatment of by-products from cellulosic ethanol production, insufficient energy utilization, and unstable boiler combustion in the existing technology, and to provide a method and application for post-treatment of by-products from cellulosic ethanol production. This method has the advantages of high energy utilization, stable boiler combustion, and no need to treat the filtrate after solid-liquid separation of by-products.

[0006] To achieve the above objectives, the first aspect of the present invention provides a method for post-processing of by-products from cellulosic ethanol production, the method comprising: evaporating and concentrating the filtrate obtained from solid-liquid separation of by-products from cellulosic ethanol production to obtain a concentrated slurry and a clear liquid, wherein the concentrated slurry is mixed with the filter residue obtained from solid-liquid separation and then co-calcined.

[0007] The mass ratio of concentrated slurry to filter residue during co-firing is 1:2-7.

[0008] The second aspect of the present invention provides the application of the method described in the first aspect in the treatment of byproducts from the production of cellulosic ethanol.

[0009] Through the above technical solution, the present invention can achieve at least the following beneficial effects:

[0010] (1) The method for post-processing of by-products from cellulosic ethanol production of the present invention does not require wastewater treatment of the filtrate after solid-liquid separation of the by-products.

[0011] (2) The method for post-processing of by-products from cellulosic ethanol production of the present invention has high energy utilization rate;

[0012] (3) In the method for post-processing of by-products of cellulosic ethanol production of the present invention, by controlling the blending ratio of concentrated slurry and filter residue, the phenomenon of filter residue binding and coking with concentrated slurry during combustion in the boiler is avoided, so that the boiler can burn stably. Detailed Implementation

[0013] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0014] The first aspect of the present invention provides a method for post-processing of by-products from cellulosic ethanol production, the method comprising: evaporating and concentrating the filtrate obtained from solid-liquid separation of by-products from cellulosic ethanol production to obtain a concentrated slurry and a clear liquid, wherein the concentrated slurry is mixed with the filter residue obtained from solid-liquid separation and then co-calcined.

[0015] The mass ratio of concentrated slurry to filter residue during co-firing is 1:2-7.

[0016] During their research, the inventors of this invention discovered that the method for post-processing byproducts of cellulosic ethanol production, as described in this invention, treats the wastewater and waste residue from the byproducts through co-firing, eliminating the need for wastewater treatment of the filtrate after solid-liquid separation, thus achieving zero wastewater discharge. Simultaneously, this method ensures full energy utilization, as the heat generated during co-firing can be used in other processes. The inventors also discovered that by controlling the co-firing ratio of the concentrated slurry after evaporation and concentration to the filter residue after solid-liquid separation, the phenomenon of the filter residue clumping and coking with the concentrated slurry during combustion in the boiler is avoided, allowing for stable boiler combustion.

[0017] In this invention, preferably, the mass ratio of the concentrated slurry to the filter residue is 1:2.5-6 (for example, it can be any two ratios from 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, or any ratio within that range).

[0018] In this invention, preferably, the content of the filtrate after solid-liquid separation of the by-products of cellulosic ethanol production is 80-87 wt% (for example, it can be any two values ​​from 80 wt%, 81 wt%, 82 wt%, 83 wt%, 84 wt%, 85 wt%, 86 wt%, 87 wt%, or any value within that range), more preferably 81-85 wt%; the content of the filter residue is 13-20 wt% (for example, it can be any two values ​​from 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, or any value within that range), more preferably 15-19 wt%.

[0019] In this invention, preferably, the byproduct of cellulosic ethanol production comprises: a lignin content of 12-15 wt% (e.g., a range formed by any two values ​​from 12 wt%, 12.2 wt%, 12.4 wt%, 12.6 wt%, 12.8 wt%, 13 wt%, 13.2 wt%, 13.4 wt%, 13.6 wt%, 13.8 wt%, 14 wt%, 14.2 wt%, 14.4 wt%, 14.6 wt%, 14.8 wt%, 15 wt%) and a soluble polysaccharide content of 0.6-0.8 wt% (e.g., a range formed by any two values ​​from 12 wt%, 12.2 wt%, 12.4 wt%, 12.6 wt%, 12.8 wt%, 13 wt%, 13.2 wt%, 13.4 wt%, 13.6 wt%, 13.8 wt%) and a soluble polysaccharide content of 0.6-0.8 wt% (e.g., a range formed by ...4 wt%, 14.2 wt%, 14.4 wt%, 14.6 wt%, 14.8 wt%) and a soluble polysaccharide content of 0.6-0.8 wt% (e.g., a range formed by two values ​​from 14 wt%, 14.2 (The range formed by any two values ​​from 0.6wt%, 0.65wt%, 0.7wt%, 0.75wt%, 0.8wt%, and the values ​​within that range) and the water content is 84-87.4wt% (e.g., the range formed by any two values ​​from 84wt%, 84.2wt%, 84.5wt%, 84.8wt%, 85wt%, 85.3wt%, 85.5wt%, 85.7wt%, 86wt%, 86.3wt%, 86.5wt%, 86.8wt%, 87wt%, 87.2wt%, 87.4wt%).

[0020] In this invention, preferably, the soluble polysaccharide refers to a class of polysaccharide substances that can be dissolved in water or other solvents, for example, it can be at least one of pectin, xanthan gum, cellobiose and xylooligosaccharides.

[0021] In this invention, preferably, the evaporation and concentration adopts a multi-stage evaporation method, more preferably a six-stage evaporation; wherein, the six-effect evaporation can adopt equipment commonly used in the art, for example, a six-effect falling film evaporator.

[0022] In this invention, preferably, the conditions for six-stage evaporation include: a first-stage evaporation temperature of 105-110℃ (for example, a range formed by any two values ​​from 105℃, 106℃, 107℃, 108℃, 109℃, and 110℃, and values ​​within that range); and a first-stage evaporation pressure of -0.035MPa to -0.025MPa (for example, a range formed by any two values ​​from -0.035MPa, -0.034MPa, -0.033MPa, -0.032MPa, -0.031MPa, -0.03MPa, -0.029MPa, -0.028MPa, -0.027MPa, -0.026MPa, and -0.025MPa). The first-stage evaporation time is 0.4-0.8 h (e.g., any two values ​​from 0.4 h, 0.5 h, 0.6 h, 0.7 h, 0.8 h can form a range or values ​​within that range); the second-stage evaporation temperature is 90-95 °C (e.g., any two values ​​from 90 °C, 91 °C, 92 °C, 93 °C, 94 °C, 95 °C can form a range or values ​​within that range); and the second-stage evaporation pressure is -0.052 MPa to -0.045 MPa (e.g., -0.052 MPa, -0.051 MPa, -0.050 MPa, -0.049 MPa, -0.048 MPa, -0.047 MPa, -0.046 MPa, -0.045 MPa). The secondary evaporation time is 0.5-0.9 h (e.g., any two values ​​from 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h); the tertiary evaporation temperature is 70-80 °C (e.g., any two values ​​from 70 °C, 71 °C, 72 °C, 73 °C, 74 °C, 75 °C, 76 °C, 77 °C, 78 °C, 79 °C, 80 °C); and the tertiary evaporation pressure is -0.07 MPa to -0.06 MPa (e.g., -0.07 MPa, -0.069 MPa, -0.068 MPa, -0.067 MPa). The evaporation range is 0.6-1h (e.g., any two values ​​from 0.6h, 0.7h, 0.8h, 0.9h, 1h); the evaporation temperature is 52-60℃ (e.g., any two values ​​from 52℃, 53℃, 54℃, 55℃, 56℃, 57℃, 58℃, 59℃, 60℃); and the evaporation pressure is -0.09MPa to -0.The pressure is 0.085 MPa (e.g., it can be any two values ​​from -0.09 MPa, -0.089 MPa, -0.088 MPa, -0.087 MPa, -0.086 MPa, -0.085 MPa, or any value within that range); the fourth-stage evaporation time is 0.6-1 h (e.g., it can be any two values ​​from 0.6 h, 0.7 h, 0.8 h, 0.9 h, 1 h, or any value within that range); the fifth-stage evaporation temperature is 54-58 °C (e.g., ...). The temperature can be any range formed by any two values ​​among 54℃, 55℃, 56℃, 57℃, and 58℃, and the value within that range. The fifth-stage evaporation pressure is -0.095MPa to -0.088MPa (for example, it can be any range formed by any two values ​​among -0.095MPa, -0.094MPa, -0.093MPa, -0.092MPa, -0.091MPa, -0.09MPa, -0.089MPa, and -0.088MPa). The fifth-stage evaporation time is 0.5-0.9 h (e.g., it can be any two values ​​from 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h, or values ​​within that range); the sixth-stage evaporation temperature is 45-50 °C (e.g., it can be any two values ​​from 45 °C, 46 °C, 47 °C, 48 °C, 49 °C, 50 °C, or values ​​within that range); and the sixth-stage evaporation pressure is -0.1 MPa to -0.092 MPa (e.g., it can be -0.1 MPa). The evaporation range is defined as any two values ​​within the range of MPa, -0.099MPa, -0.098MPa, -0.097MPa, -0.096MPa, -0.095MPa, -0.094MPa, -0.093MPa, and -0.092MPa, and the values ​​within that range. The evaporation time for the sixth stage is 0.4-0.8 hours (for example, it can be any two values ​​within the range of 0.4h, 0.5h, 0.6h, 0.7h, and 0.8h).

[0023] In this invention, more preferably, the evaporation conditions of the six-stage evaporator may include: a first-stage evaporation temperature of 108-112℃, a first-stage evaporation pressure of -0.032MPa to -0.028MPa, and a first-stage evaporation time of 0.5-0.7h; a second-stage evaporation temperature of 92-94℃, a second-stage evaporation pressure of -0.05MPa to -0.048MPa, and a second-stage evaporation time of 0.6-0.8h; and a third-stage evaporation temperature of 72-78℃ and a third-stage evaporation pressure of -0.069MPa to -0.065MPa. The evaporation time for the third stage is 0.7-0.9 hours; the evaporation temperature for the fourth stage is 61-63℃, the evaporation pressure for the fourth stage is -0.088MPa to -0.086MPa, and the evaporation time for the fourth stage is 0.7-0.9 hours; the evaporation temperature for the fifth stage is 56-58℃, the evaporation pressure for the fifth stage is -0.094MPa to -0.09MPa, and the evaporation time for the fifth stage is 0.6-0.8 hours; and the evaporation temperature for the sixth stage is 52-54℃, the evaporation pressure for the sixth stage is -0.098MPa to -0.095MPa, and the evaporation time for the sixth stage is 0.5-0.7 hours.

[0024] In this invention, preferably, the dry matter content in the filtrate is ≤6.4wt% (for example, it can be any two values ​​formed by 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.2wt%, 4.4wt%, 4.6wt%, 4.8wt%, 5wt%, 5.2wt%, 5.4wt%, 5.6wt%, 5.8wt%, 6wt%, 6.2wt%, 6.4wt%, and values ​​within that range), more preferably 4-6wt%.

[0025] In this invention, preferably, the moisture content in the filter residue is ≤50wt% (for example, it can be any two values ​​formed by 20wt%, 22wt%, 24wt%, 26wt%, 28wt%, 30wt%, 32wt%, 34wt%, 36wt%, 38wt%, 40wt%, 41wt%, 42wt%, 43wt%, 44wt%, 45wt%, 46wt%, 47wt%, 48wt%, 50wt%, or a value within that range), preferably 40-48wt%.

[0026] In this invention, preferably, based on the total weight of the material after evaporation and concentration, the content of the concentrated slurry is 8-15 wt% (for example, it can be any two values ​​formed by 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, 10 wt%, 10.5 wt%, 11 wt%, 11.5 wt%, 12 wt%, 12.5 wt%, 13 wt%, 13.5 wt%, 14 wt%, 14.5 wt%, 15 wt%, or values ​​within that range), more Preferably, it is 9-14 wt%; the content of the supernatant is 85-92 wt% (for example, it can be any two values ​​formed by 85 wt%, 85.5 wt%, 86 wt%, 86.5 wt%, 87 wt%, 87.5 wt%, 88 wt%, 88.5 wt%, 89 wt%, 89.5 wt%, 90 wt%, 90.5 wt%, 91 wt%, 91.5 wt%, 92 wt%, and values ​​within the range), more preferably 86-91 wt%.

[0027] In this invention, preferably, the water content of the slurry is 35-50 wt% (for example, it can be any two values ​​formed by 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 values ​​within that range), more preferably 40-45 wt%.

[0028] In this invention, by controlling the water content in the slurry and controlling the blending ratio of the slurry and the filter residue, the phenomenon of the filter residue sticking and coking with the slurry during combustion in the boiler can be better avoided, so that the boiler can burn stably and its co-firing heat generation efficiency is better.

[0029] In this invention, preferably, the co-firing method includes: injecting a concentrated slurry into a boiler through a spray gun system equipped with swirl vanes. The addition of swirl vanes improves the atomization effect of the concentrated slurry entering the boiler. The swirl vanes can be the swirl vanes commonly used in boiler nozzles.

[0030] In this invention, preferably, compressed air is introduced into the spray gun system to make the pressure inside the spray gun system 10-50 kPa (for example, it can be any two values ​​formed by 10 kPa, 12 kPa, 15 kPa, 18 kPa, 20 kPa, 23 kPa, 25 kPa, 27 kPa, 30 kPa, 33 kPa, 35 kPa, 38 kPa, 40 kPa, 42 kPa, 45 kPa, 47 kPa, 50 kPa and the value within the range), more preferably 15-40 kPa.

[0031] In this invention, preferably, the spray gun system includes a gas-liquid mixer and a spray gun.

[0032] In this invention, preferably, the operating conditions of the gas-liquid mixer include: the operating pressure of the slurry is 12 kPa-55 kPa (for example, it can be any two values ​​from 12 kPa, 15 kPa, 18 kPa, 20 kPa, 23 kPa, 25 kPa, 27 kPa, 30 kPa, 33 kPa, 35 kPa, 38 kPa, 40 kPa, 42 kPa, 45 kPa, 47 kPa, 50 kPa, 52 kPa, 55 kPa, forming a range and within the range). The value of the compressed air is preferably 18-50 kPa; the operating pressure of the compressed air is 10-50 kPa (for example, it can be any two values ​​formed by 10 kPa, 12 kPa, 15 kPa, 18 kPa, 20 kPa, 23 kPa, 25 kPa, 27 kPa, 30 kPa, 33 kPa, 35 kPa, 38 kPa, 40 kPa, 42 kPa, 45 kPa, 47 kPa, 50 kPa and the value within the range), more preferably 15-40 kPa.

[0033] In this invention, preferably, the slurry temperature of the spray gun is 75-95℃ (for example, it can be any two values ​​formed by 75℃, 76℃, 77℃, 78℃, 79℃, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, 93℃, 94℃, 95℃, or values ​​within that range), preferably 80-90℃; the spray gun flow rate is ≤5t / h (for example, it can be 1t / h, 1.5t / h, 2t / h, 2.5t / h, 3t / h, 3.5t / h). The flow rate is 2-4 t / h; the slurry water content is 35-50 wt% (for example, it can be any two values ​​formed within the range of 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%), preferably 40-45 wt%.

[0034] In this invention, preferably, the spray gun system is located at 2 / 5-3 / 5 of the furnace side wall.

[0035] In this invention, preferably, the heat generated by the co-firing provides energy for evaporation and concentration. Specifically, the energy generated by the co-firing can be used by any energy-required process section or stored as electrical energy. In this embodiment of the invention, to obtain more intuitive data on the energy generated by the co-firing, the energy is converted into electrical energy for representation.

[0036] In a preferred embodiment of the present invention, the post-treatment of the flue gas after co-firing employs commonly used desulfurization and denitrification methods in the art, such as the PNCR polymer denitrification process. Specifically, without a catalyst at the boiler tail end, when the flue gas temperature at the boiler cyclone separator outlet is ≥700℃, a polymeric denitrification agent (the polymeric denitrification agent can be a commonly used substance in the art, and its dosage is not particularly limited, for example, 20-80 kg / h) is injected into the boiler cyclone separator inlet. The polymeric denitrification agent rapidly decomposes in the flue gas, reacting with NO in the flue gas. x The reaction produces N2 and H2O, but does not react with oxygen in the flue gas; dry flue gas desulfurization technology is adopted, using lime nitrate as the desulfurization absorbent, and desulfurization treatment is carried out in a single tower.

[0037] The second aspect of the present invention provides the application of the method described in the first aspect in the treatment of byproducts from the production of cellulosic ethanol.

[0038] The present invention will be described in detail below through embodiments. In the following embodiments, the environmental parameters of boiler flue gas are measured by an online monitoring system; the Testo 350 boiler flue gas online monitoring instrument is a commercially available product from Germany.

[0039] The byproducts of cellulosic ethanol production include: 12 wt% lignin, 0.3 wt% cellobiose, 0.3 wt% xylose, 0.2 wt% arabinose, 2 wt% soluble lignin, 1.8 wt% inorganic salts, and 83.4 wt% water.

[0040] Example 1

[0041] (1) The byproducts of cellulosic ethanol production are separated into solid and liquid by filtration using a diaphragm plate and frame filter press to obtain 15 wt% filter residue and 85 wt% filtrate; wherein the dry matter content of the filtrate is 4 wt% and the moisture content of the filter residue is 40 wt%.

[0042] (2) The filtrate was evaporated and concentrated to obtain a concentrated slurry. The evaporation and concentration equipment adopted a six-effect falling film evaporator. The evaporation conditions were as follows: the evaporation temperature of the first effect was 110℃, the evaporation pressure was -0.03MPa, and the evaporation time was 0.5h; the evaporation temperature of the second effect was 93℃, the evaporation pressure was -0.05MPa, and the evaporation time was 0.6h; the evaporation temperature of the third effect was 75℃, the evaporation pressure was -0.067MPa, and the evaporation time was 0.7h; the evaporation temperature of the fourth effect was 62℃, the evaporation pressure was -0.087MPa, and the evaporation time was 0.7h; the evaporation temperature of the fifth effect was 57℃, the evaporation pressure was -0.092MPa, and the evaporation time was 0.7h; and the evaporation temperature of the sixth effect was 53℃, the evaporation pressure was -0.096MPa, and the evaporation time was 0.5h. After evaporation and concentration, the content of the concentrated slurry was 9wt%, the content of the clear liquid was 91wt%, and the water content of the concentrated slurry was 40wt%.

[0043] (3) The concentrated slurry is injected into the boiler through a spray gun system equipped with swirl vanes (compressed air is introduced into the spray gun system to make the pressure inside the spray gun system 15 kPa; the spray gun system is set in a secondary air duct 3.1 meters away from the boiler bed surface) to be co-fired with the filter residue; the concentrated slurry injection rate is 2 t / h, and the co-firing mass ratio of concentrated slurry to filter residue in the boiler is 1:6; the spray gun system includes: a gas-liquid mixer and a spray gun; the operating conditions of the gas-liquid mixer are: the operating pressure of the concentrated slurry is 18 kPa; the operating pressure of the compressed air is 15 kPa; the operating conditions of the spray gun are: the concentrated slurry temperature is 80℃; the spray gun flow rate is 2 t / h; and the concentrated slurry water content is 40 wt%. The energy generated by co-firing provides energy for evaporation and concentration (the data of co-firing energy converted into electrical energy are shown in Table 1).

[0044] (4) After the flue gas temperature at the boiler cyclone separator outlet reaches ≥700℃, a polymeric denitrification agent (the polymeric denitrification agent is a commercially available product purchased from Shandong Boao Environmental Protection Technology Co., Ltd., with CAS number A88960-35) is injected into the cyclone separator inlet at a rate of 45kg / h for denitrification treatment; a medium-sized single tower (the desulfurization absorbent is quicklime) is used for desulfurization treatment.

[0045] The boiler coking cycle and furnace temperature fluctuation range are shown in Table 1, and the composition of the emitted flue gas is shown in Table 2.

[0046] Example 2

[0047] (1) The byproducts of cellulosic ethanol production were separated into solid and liquid by filtration using a diaphragm plate and frame filter press to obtain 19 wt% filter residue and 81 wt% filtrate; wherein the dry matter content of the filtrate was 6 wt% and the moisture content of the filter residue was 48 wt%.

[0048] (2) The filtrate was evaporated and concentrated to obtain a concentrated slurry. The evaporation and concentration equipment adopted a six-effect falling film evaporator. The evaporation conditions were as follows: the evaporation temperature of the first effect was 108℃, the evaporation pressure was -0.028MPa, and the evaporation time was 0.6h; the evaporation temperature of the second effect was 92℃, the evaporation pressure was -0.049MPa, and the evaporation time was 0.7h; the evaporation temperature of the third effect was 72℃, the evaporation pressure was -0.069MPa, and the evaporation time was 0.8h; the evaporation temperature of the fourth effect was 61℃, the evaporation pressure was -0.086MPa, and the evaporation time was 0.8h; the evaporation temperature of the fifth effect was 58℃, the evaporation pressure was -0.09MPa, and the evaporation time was 0.6h; and the evaporation temperature of the sixth effect was 52℃, the evaporation pressure was -0.095MPa, and the evaporation time was 0.6h. After evaporation and concentration, the content of the concentrated slurry was 14wt%, the content of the clear liquid was 86wt%, and the water content of the concentrated slurry was 45wt%.

[0049] (3) The concentrated slurry is injected into the boiler through a spray gun system equipped with swirl vanes (compressed air is introduced into the spray gun system to make the pressure inside the spray gun system 40 kPa; the spray gun system is set in a secondary air duct 3.1 meters away from the boiler bed surface) to be co-fired with the filter residue; the concentrated slurry injection rate is 4 t / h, and the co-firing volume ratio of concentrated slurry to filter residue in the boiler is 1:2.5; the spray gun system includes: a gas-liquid mixer and a spray gun; the operating conditions of the gas-liquid mixer are: the operating pressure of the concentrated slurry is 50 kPa; the operating pressure of the compressed air is 40 kPa; the operating conditions of the spray gun are: the temperature of the concentrated slurry is 90℃; the spray gun flow rate is 4 t / h; and the water content of the concentrated slurry is 45 wt%. The energy generated by co-firing provides energy for evaporation and concentration (the data of co-firing energy converted into electrical energy are shown in Table 1).

[0050] (4) After the flue gas temperature at the boiler cyclone separator outlet reaches ≥700℃, a high-molecular denitrification agent (45kg / h) is sprayed into the cyclone separator inlet for denitrification treatment; a medium-sized single tower (desulfurization absorbent is quicklime) is used for desulfurization treatment.

[0051] The boiler coking cycle and furnace temperature fluctuation range are shown in Table 1, and the composition of the emitted flue gas is shown in Table 2.

[0052] Example 3

[0053] (1) The byproducts of cellulosic ethanol production were separated into solid and liquid by filtration using a diaphragm plate and frame filter press to obtain 17 wt% filter residue and 83 wt% filtrate; wherein the dry matter content of the filtrate was 5 wt% and the moisture content of the filter residue was 44 wt%.

[0054] (2) The filtrate was evaporated and concentrated to obtain a concentrated slurry. The evaporation and concentration equipment adopted a six-effect falling film evaporator. The evaporation conditions were as follows: the first effect evaporation temperature was 112℃, the evaporation pressure was -0.032MPa, and the evaporation time was 0.7h; the second effect evaporation temperature was 94℃, the evaporation pressure was -0.048MPa, and the evaporation time was 0.8h; the third effect evaporation temperature was 78℃, the evaporation pressure was -0.065MPa, and the evaporation time was 0.9h; the fourth effect evaporation temperature was 63℃, the evaporation pressure was -0.088MPa, and the evaporation time was 0.9h; the fifth effect evaporation temperature was 56℃, the evaporation pressure was -0.094MPa, and the evaporation time was 0.8h; and the sixth effect evaporation temperature was 54℃, the evaporation pressure was -0.098MPa, and the evaporation time was 0.7h. After evaporation and concentration, the content of the concentrated slurry was 11wt%, the content of the clear liquid was 89wt%, and the water content of the concentrated slurry was 42wt%.

[0055] (3) The concentrated slurry is injected into the boiler through a spray gun system equipped with swirl vanes (compressed air is introduced into the spray gun system to make the pressure inside the spray gun system 28 kPa; the spray gun system is set in a secondary air duct 3.1 meters away from the boiler bed surface) to be co-fired with the filter residue; the concentrated slurry injection rate is 3 t / h, and the co-firing volume ratio of concentrated slurry to filter residue in the boiler is 1:4; the spray gun system includes: a gas-liquid mixer and a spray gun; the operating conditions of the gas-liquid mixer are: the operating pressure of the concentrated slurry is 30 kPa; the operating pressure of the compressed air is 28 kPa; the operating conditions of the spray gun are: the temperature of the concentrated slurry is 85℃; the spray gun flow rate is 3 t / h; and the water content of the concentrated slurry is 42 wt%. The energy generated by co-firing provides energy for evaporation and concentration (the data of co-firing energy converted into electrical energy are shown in Table 1).

[0056] (4) After the flue gas temperature at the boiler cyclone separator outlet reaches ≥700℃, a high-molecular denitrification agent (45kg / h) is sprayed into the cyclone separator inlet for denitrification treatment; a medium-sized single tower (desulfurization absorbent is quicklime) is used for desulfurization treatment.

[0057] The boiler coking cycle and furnace temperature fluctuation range are shown in Table 1, and the composition of the emitted flue gas is shown in Table 2.

[0058] Example 4

[0059] The by-products of cellulosic ethanol production were processed according to the method of Example 3, except that in step (2), a six-effect falling film evaporator was not used for evaporation and concentration, but a single-stage evaporation was used, with the evaporation conditions being a temperature of 40°C, so that the water content of the concentrated slurry was 60 wt%.

[0060] Example 5

[0061] The post-processing of by-products from cellulosic ethanol production was carried out according to the method of Example 3, except that in step (3), the amount of concentrated slurry co-firing in the boiler was 5t / h.

[0062] Example 6

[0063] The post-processing of byproducts from cellulosic ethanol production was carried out according to the method of Example 3, except that in step (1), the water content of the filter residue after solid-liquid separation was 52 wt%.

[0064] Example 7

[0065] The by-products of cellulosic ethanol production were processed according to the method in Example 3, except that in step (3), the mass ratio of the concentrated slurry to the filter residue in the boiler was 1:2.

[0066] Example 8

[0067] The post-processing of byproducts from cellulosic ethanol production was carried out according to the method of Example 3, except that in step (3), the moisture content of the filter residue was 60 wt%.

[0068] Comparative Example 1

[0069] The post-processing of by-products from cellulosic ethanol production was carried out according to the method of Example 3, except that in step (3), the volume ratio of the concentrated slurry to the filter residue in the boiler was 1:1.

[0070] Comparative Example 2

[0071] The post-processing of byproducts from cellulosic ethanol production was carried out according to the method of Example 3, except that step (2) was omitted and the filtrate was directly subjected to step (3).

[0072] Table 1

[0073] Example 1 180 750-810 4600 Example 2 175 730-800 4300 Example 3 170 720-800 4100 Example 4 35 650-750 3900 Example 5 20 600-700 2400 Example 6 15 600-700 1640 Example 7 1 600-650 700 Example 8 1 540-620 0 Comparative Example 1 0 400-550 0 Comparative Example 2 0 ≤450 0

[0074] As can be seen from the results in Table 1, by controlling the moisture content and co-firing ratio of the concentrated slurry after evaporation and concentration and the filter residue after solid-liquid separation, the present invention can effectively avoid the phenomenon of filter residue sticking and coking with the concentrated slurry during combustion in the boiler, so that the boiler can burn stably and has significantly better effects on boiler energy utilization and stable combustion.

[0075] Table 2

[0076]

[0077] As can be seen from the results in Table 2, the post-treatment method of the present invention can effectively reduce SO2 and NO in flue gas emissions. X The content of [something] reduces the pollution of the environment caused by flue gas emissions.

[0078] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for post-processing of byproducts from cellulosic ethanol production, characterized in that, The method includes: evaporating and concentrating the filtrate obtained from the solid-liquid separation of by-products of cellulosic ethanol production to obtain a concentrated slurry and a clear liquid; and mixing the concentrated slurry with the filter residue obtained from the solid-liquid separation for co-firing. The mass ratio of concentrated slurry to filter residue during co-firing is 1:2-7.

2. The method according to claim 1, wherein, The mass ratio of the concentrated slurry to the filter residue is 1:2.5-6. And / or, the content of the filtrate after solid-liquid separation of the by-products of cellulosic ethanol production is 80-87 wt%, preferably 81-85 wt%; the content of the filter residue is 13-20 wt%, preferably 15-19%. And / or, the byproducts of the cellulosic ethanol production comprise: 12-15 wt% lignin, 0.6-0.8 wt% soluble polysaccharides, and 84-87.4 wt% water.

3. The method according to claim 1 or 2, wherein, The evaporation and concentration process employs a multi-stage evaporation method, preferably a six-stage evaporation method. Preferably, the conditions for the six-stage evaporation include: a first-stage evaporation temperature of 105-115℃, a first-stage evaporation pressure of -0.035MPa to -0.025MPa, and a first-stage evaporation time of 0.4-0.8h; a second-stage evaporation temperature of 90-95℃, a second-stage evaporation pressure of -0.052MPa to -0.045MPa, and a second-stage evaporation time of 0.5-0.9h; and a third-stage evaporation temperature of 70-80℃, a third-stage evaporation pressure of -0.07MPa to -0.06MPa, and a third-stage evaporation time of... The evaporation time for the fourth stage is 0.6-1h; the evaporation temperature for the fifth stage is 60-65℃, the evaporation pressure for the fifth stage is -0.09MPa to -0.085MPa, and the evaporation time for the fifth stage is 0.6-1h; the evaporation temperature for the fifth stage is 55-60℃, the evaporation pressure for the fifth stage is -0.095MPa to -0.088MPa, and the evaporation time for the fifth stage is 0.5-0.9h; the evaporation temperature for the sixth stage is 50-55℃, the evaporation pressure for the sixth stage is -0.1MPa to -0.092MPa, and the evaporation time for the sixth stage is 0.4-0.8h.

4. The method according to claim 1 or 2, wherein, The dry matter content in the filtrate is ≤6.4wt%, preferably 4-6wt%; And / or, the moisture content in the filter residue is ≤50wt%, preferably 40-48wt%.

5. The method according to claim 1 or 2, wherein, Based on the total weight of the material after evaporation and concentration, the content of the concentrated slurry is 8-15 wt%, preferably 9-14 wt%; the content of the clarified liquid is 85-92 wt%, preferably 86-91 wt%.

6. The method according to claim 1 or 2, wherein, The water content of the slurry is 35-50 wt%, preferably 40-45 wt%.

7. The method according to claim 1 or 2, wherein, The co-firing method includes: injecting the concentrated slurry into the boiler through a spray gun system equipped with swirl vanes; Preferably, compressed air is introduced into the spray gun system to make the pressure inside the spray gun system 10-50 kPa, more preferably 15-40 kPa.

8. The method according to claim 7, wherein, The spray gun system includes: a gas-liquid mixer and a spray gun; Preferably, the operating conditions of the gas-liquid mixer include: the operating pressure of the slurry is 12 kPa-55 kPa, preferably 18-50 kPa; and the operating pressure of the compressed air is 10-50 kPa, more preferably 15-40 kPa. Preferably, the temperature of the slurry in the spray gun is 75-95℃, more preferably 80-90℃; the flow rate of the spray gun is ≤5t / h, more preferably 2-4t / h; and the water content of the slurry is 35-50wt%, more preferably 40-45wt%. And / or, the spray gun system is located at 2 / 5-3 / 5 of the furnace sidewall.

9. The method according to claim 1, wherein, The heat generated by the co-firing provides energy for evaporation and concentration.

10. The use of the method according to any one of claims 1-9 in the treatment of byproducts from the production of cellulosic ethanol.

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