Method for preparing sludge biomass fuel particles by mixing municipal sludge with sawdust

Abstract

The present invention discloses a method for preparing sludge biomass fuel particles by mixing municipal sludge with sawdust, comprising: taking a municipal sludge sample and dividing it into I portions; adding each of the municipal sludge samples into I culture vessels; controlling the culture temperature of each of the culture vessels to correspond to I culture temperature intervals [T i‑L ,T i‑H ], in response to the colony density of the fermentation microorganisms in the culture vessel reaching a preset density, a sludge fermentation agent Y is obtained. i Put the municipal sludge into the fermentation tower, and add sawdust according to the water content of the municipal sludge to keep the water content of the municipal sludge at 45-60%; according to the temperature in the fermentation tower, inoculate the sludge fermentation agent Y i In response to the colony density of the fermentation microorganisms corresponding to the last added sludge fermentation agent reaching a preset requirement, the municipal sludge is removed and granulated to obtain biomass fuel pellets. The present invention improves the fermentation efficiency of municipal sludge, thereby improving the production efficiency of biomass fuel pellets.

Description

Technical Field

[0001] The present invention relates to the field of new energy, and in particular to a method for preparing sludge biomass fuel particles by mixing municipal sludge with sawdust. Background Art

[0002] Municipal sludge is a wastewater treatment byproduct containing numerous pollutants, generated by sewage treatment plants during the treatment of domestic and industrial wastewater. With the rapid growth of my country's sewage treatment rate and the resulting sludge production, municipal sludge has reached over 30 million tons annually (with a moisture content of 80%). Appearing to be black or dark brown, municipal sludge appears as fluid, semi-fluid, or cake-like flocs. Characterized by a high moisture content, it is bulky and has a complex composition. Sludge contains solid particles such as mud, sand, fibers, plant and animal debris, and their aggregated flocs. It also contains large amounts of organic matter (primarily benzene and chlorophenols), toxic and hazardous heavy metals, pathogenic microorganisms, parasite eggs, salts, and radionuclides, among other persistent substances, causing serious environmental pollution. Currently, landfill is the primary sludge disposal method both domestically and internationally. However, the increasing sludge production not only occupies land but also pollutes groundwater. Incineration is a trend in sludge treatment internationally, but the initial investment and operating costs of incinerators are high.

[0003] Existing technologies can utilize the calorific value of municipal sludge to produce biomass fuel. However, the sludge-to-biomass fuel process requires dehydration and drying to ensure successful biomass fuel production. Existing methods utilize fermentation of the sludge, utilizing aerobic thermophilic bacteria to decompose organic matter in the sludge, generating heat and rapidly removing water. However, existing technologies suffer from a slow fermentation process and low dehydration efficiency, resulting in a low biomass fuel production rate. Summary of the Invention

[0004] The applicant's research has found that using fermentative microorganisms grown in municipal sludge as a fermentation agent and inoculating it into the sludge for fermentation can rapidly adapt to the sludge environment, rapidly reproduce and ferment, and accelerate dehydration and drying efficiency. However, if the fermentation agent is inoculated into the sludge at the beginning of the temperature range where the corresponding microorganism is most suitable for survival, the microorganisms of the previously inoculated fermentation agent will not have fully decayed, resulting in fierce competition with the microorganisms of the currently inoculated fermentation agent, resulting in reduced fermentation efficiency and a subsequent decrease in dehydration and drying efficiency.

[0005] In view of some of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a method for preparing sludge biomass fuel particles by mixing municipal sludge with sawdust, aiming to improve the fermentation efficiency of municipal sludge and thus improve the preparation efficiency of biomass fuel particles.

[0006] To achieve the above object, the present invention provides a method for preparing sludge biomass fuel particles by mixing municipal sludge with sawdust, the method comprising:

[0007] Take a municipal sludge sample and divide it into I parts. Add I parts of the municipal sludge sample into I culture vessels respectively. Control the culture temperature of I culture vessels to correspond to I culture temperature intervals divided into 10-75°C [T i-L ,T i-H ], in response to the colony density of the fermentation microorganisms in the culture vessel reaching a preset density, obtaining sludge fermentation agent Y i ; Wherein, i is an integer number of the culture temperature intervals in ascending order and 0<i≤I, the sludge fermentation agent Y i The corresponding growth temperature interval is the i-th culture temperature interval [T i-L ,T i-H ];

[0008] Putting the municipal sludge into a fermentation tower, and adding sawdust according to the water content of the municipal sludge, so that the water content of the municipal sludge is maintained at 45-60%;

[0009] According to the temperature in the fermentation tower, the sludge fermentation agent Y is inoculated. i Wherein, in response to the temperature in the fermentation tower exceeding the current sludge fermentation agent Y i The corresponding growth temperature range and continued fermentation in the colony decline period, and reached the next sludge fermentation agent Y i+1 The corresponding growth temperature range median T i+1-M , inoculate the next sludge fermentation agent Y i+1 ; Wherein, the sludge fermentation agent Y i In the temperature range [T i-H ,T i+1-M ] The fermentation operation period is the colony decline period;

[0010] In response to the fact that the colony density of the fermentation microorganisms corresponding to the last added sludge fermentation agent reaches a preset requirement, the municipal sludge is taken out for granulation to obtain biomass fuel particles.

[0011] Optionally, in response to the colony density of the fermentation microorganisms in the culture vessel reaching a preset density, the sludge fermentation agent Y is obtained. i ,include:

[0012] In response to the colony density of the fermentation microorganisms in the culture vessel reaching 4×10 8 -6.5×10 8 CFU / ml, it is judged that the fermentation microorganism culture is complete, and the sludge fermentation agent Y is obtained. i ; The colony density only counts the effective living bacteria.

[0013] Optionally, the adding of sawdust according to the water content of the municipal sludge to maintain the water content of the municipal sludge at 45-60% comprises:

[0014] detecting the water content of the municipal sludge;

[0015] Sawdust is added according to the water content of the municipal sludge to keep the water content of the municipal sludge at 45-60%, while ensuring that the calorific value of the biomass fuel particles prepared after the fermentation of the municipal sludge meets the minimum combustion standard.

[0016] Optionally, after the municipal sludge is fed into the fermentation tower, the method further comprises:

[0017] A blower is used to introduce air from the bottom and / or side of the fermentation tower to ensure that the oxygen content at each position in the fermentation tower is maintained at 5-15v / v%.

[0018] Optionally, the removing of the municipal sludge and granulating the sludge to obtain biomass fuel pellets comprises:

[0019] Taking out the fermented municipal sludge and crushing it into 60-80 mesh;

[0020] Add combustion aid to the crushed municipal sludge and mix well;

[0021] The evenly mixed municipal sludge is fed into an extruder to obtain the biomass fuel particles.

[0022] Optionally, after removing the municipal sludge and granulating it to obtain biomass fuel pellets, the method further comprises:

[0023] The biomass fuel particles are dried to reduce the moisture content in the biomass fuel particles and improve the combustion performance of the biomass fuel particles.

[0024] Optionally, before feeding the municipal sludge into the fermentation tower, the method further comprises:

[0025] The municipal sludge is subjected to desulfurization treatment to reduce the sulfur content of the municipal sludge.

[0026] Optionally, before adding sawdust according to the water content of the municipal sludge to maintain the water content of the municipal sludge at 45-60%, the method further comprises:

[0027] The sawdust is carbonized to reduce the organic matter content in the sawdust.

[0028] Beneficial effects of the present invention: 1. The present invention responds to the temperature in the fermentation tower exceeding the current sludge fermentation agent Yi The corresponding growth temperature range and continue to ferment in the colony decline period (in the colony decline period, the current sludge fermentation agent Y i The number of fermentation microorganisms gradually decreases, but because its number is still relatively large, it still serves as the main fermentation microorganism for municipal sludge fermentation) and reaches the next sludge fermentation agent Y i+1 The corresponding growth temperature range median T i+1-M , inoculate the next sludge fermentation agent Y i+1 The present invention is based on the current sludge fermentation agent Y i The fermentation microorganisms in the corresponding growth temperature range of the upper limit temperature to the next sludge fermentation agent Y i+1 The corresponding growth temperature range median T i+1-M After the colony declines, add the next sludge fermentation agent Y i+1 , can effectively reduce the current sludge fermentation agent Y i The fermentation microorganisms and the next sludge fermentation agent Y i+1 competition of fermentation microorganisms to ensure the next sludge fermentation agent Y i+1 The fermentation microorganisms can grow and reproduce normally after inoculation, thereby accelerating the fermentation efficiency. 2. The present invention divides the municipal sludge sample into 1 part, adds 1 part of the municipal sludge sample to 1 culture vessel, and controls the culture temperature of 1 culture vessel to correspond to 1 culture temperature range [T i-L ,T i-H ], in response to the colony density of the fermentation microorganisms in the culture vessel reaching a preset density, a sludge fermentation agent Y is obtained. i . The present invention uses microorganisms cultivated in municipal sludge itself as a fermentation agent. Compared with external fermentation agents, it can adapt to the municipal sludge environment faster, grow and reproduce faster during the fermentation process to decompose organic matter in the municipal sludge. 3. The present invention puts the municipal sludge into the fermentation tower, and adds sawdust according to the water content of the municipal sludge to keep the water content of the municipal sludge at 45-60%. The present invention adjusts the water content of the municipal sludge by sawdust, and can improve the calorific value of the product biomass fuel particles while ensuring the effective regulation of the water content. 4. The present invention inoculates the sludge fermentation agent Y according to the temperature in the fermentation tower. i. The fermentation agent of the present invention is inoculated in different temperature sections, which ensures that the fermentation microorganisms in different temperature sections can form a larger colony scale for fermentation at the first time of inoculation, while the existing one-time inoculation can only wait for a certain period of time after reaching the temperature section before the fermentation microorganisms in the temperature section can form a larger colony scale, thereby accelerating the fermentation efficiency. 5. The present invention can accurately and effectively judge whether the fermentation is completed by the fermentation microorganism colony density corresponding to the last added sludge fermentation agent to meet the preset requirements. 6. The present invention can carbonize the sawdust in advance to reduce the organic matter content in the sawdust. Avoid the situation where the sawdust is also excessively decomposed by the fermentation microorganisms and the calorific value is reduced. In summary, the present invention achieves the purpose of improving the preparation efficiency of biomass fuel particles by accelerating the fermentation step in the process of preparing biomass fuel particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention provides a flow chart of a method for preparing sludge biomass fuel particles by mixing municipal sludge with sawdust, according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0030] The present invention discloses a method for preparing sludge biomass fuel pellets by blending municipal sludge with sawdust. Those skilled in the art may refer to the contents herein and appropriately improve the technical details for implementation. It is particularly important to note that all similar substitutions and modifications obvious to those skilled in the art are considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments. It is obvious that relevant persons can modify or appropriately alter and combine the methods and applications described herein without departing from the content, spirit, and scope of the present invention to implement and apply the technology of the present invention.

[0031] The applicant's research has found that using fermentative microorganisms grown in municipal sludge as a fermentation agent and inoculating it into the sludge for fermentation can rapidly adapt to the sludge environment, rapidly reproduce and ferment, and accelerate dehydration and drying efficiency. However, if the fermentation agent is inoculated into the sludge at the beginning of the temperature range that is most suitable for the survival of its corresponding microorganism, the microorganisms of the previously inoculated fermentation agent will not have fully decayed, and the microorganisms of the currently inoculated fermentation agent will compete fiercely with the corresponding microorganisms, resulting in reduced fermentation efficiency and a subsequent decrease in dehydration and drying efficiency. The slow fermentation rate of municipal sludge significantly slows the preparation of biomass fuel pellets.

[0032] Therefore, the embodiment of the present invention provides a method for preparing sludge biomass fuel particles by mixing municipal sludge with sawdust, such as Figure 1 As shown, the method includes:

[0033] Step S101: Take a municipal sludge sample and divide it into I parts. Add each part of the municipal sludge sample into I culture vessels respectively. Control the culture temperature of each culture vessel to correspond to I culture temperature intervals [T i-L ,T i-H ], in response to the colony density of the fermentation microorganisms in the culture vessel reaching a preset density, a sludge fermentation agent Y is obtained. i .

[0034] Where i is an integer number of the culture temperature intervals in ascending order and 0<i≤I, sludge fermentation agent Y i The corresponding growth temperature interval is the i-th cultivation temperature interval [T i-L ,T i-H The culture vessel contains a culture medium corresponding to the fermentation microorganism in the culture temperature range.

[0035] It should be noted that municipal sludge contains a wide variety of fermentation microorganisms, and different types of fermentation microorganisms have different suitable growth temperatures. For example, the suitable growth temperature range of Bacillus subtilis is 30-40°C, and the suitable growth temperature range of Thermosulfur Sulfobacillus sulfoxidans is 50-60°C. By culturing municipal sludge under different temperature environments, the fermentation microorganisms that are suitable for growth at this temperature form larger colonies and become fermentation agents. The existing technology generally only inoculates the fermentation agent once, allowing the population in the fermentation agent to change as the municipal sludge ferments and heats up. This results in that when a certain fermentation microorganism reaches a suitable temperature range, it must first be allowed to grow and reproduce for a period of time before large-scale fermentation can be carried out. For example, when it reaches 30°C, Bacillus subtilis should start to act as the main fermentation bacteria, but when it just reaches 30°C, the number of Bacillus subtilis colonies is obviously not enough to ferment on a large scale. The embodiment of the present invention directly inoculates the corresponding fermentation agent in different temperature ranges, which effectively avoids this problem.

[0036] Optionally, in response to the colony density of the fermentation microorganisms in the culture vessel reaching a preset density, a sludge fermentation agent Y is obtained. i ,include:

[0037] When the colony density of the fermentation microorganisms in the culture vessel reaches 4×10 8 -6.5×10 8 CFU / ml, judging that the fermentation microorganism culture is complete, and obtaining sludge fermentation agent Y i ; Among them, the colony density only counts the effective living bacteria.

[0038] The colony density reached 4×10 8 -6.5×10 8 CFU / ml is the standard of the starter culture of the present invention obtained through experiments. Under the premise that it is sufficient to be used as a starter culture, the culture cycle is short.

[0039] Step S102: putting the municipal sludge into the fermentation tower, and adding sawdust according to the water content of the municipal sludge, so as to keep the water content of the municipal sludge at 45-60%.

[0040] Optionally, sawdust is added according to the moisture content of the municipal sludge to keep the moisture content of the municipal sludge at 45-60%, including:

[0041] Testing the moisture content of municipal sludge;

[0042] Sawdust is added according to the moisture content of municipal sludge to keep the moisture content of municipal sludge at 45-60%, while ensuring that the calorific value of biomass fuel particles prepared after the municipal sludge fermentation is completed meets the minimum combustion standard.

[0043] It should be noted that municipal sludge generally has a high moisture content. When the moisture content exceeds 65%, water fills the gaps between sludge particles, blocking air passages and significantly reducing the air content. This causes fermentation to transition from aerobic to anaerobic conditions, leading to a sharp drop in temperature and the formation of smelly intermediates. Therefore, sawdust is needed to adjust the moisture content. Adding sawdust can also address the low calorific value of municipal sludge.

[0044] Step S103: Inoculate sludge fermentation agent Y according to the temperature in the fermentation tower i Wherein, in response to the temperature in the fermentation tower exceeding the current sludge fermentation agent Y i The corresponding growth temperature range and continued fermentation in the colony decline period, and reached the next sludge fermentation agent Y i+1 The corresponding growth temperature range median T i+1-M , inoculate the next sludge fermentation agent Y i+1 .

[0045] Among them, sludge fermentation agent Y i In the temperature range [T i-H ,T i+1-M ]The fermentation operation period is the colony decline period.

[0046] Specifically, the first inoculation of sludge fermentation agent is based on the temperature in the fermentation tower, and the fermentation agent with the growth temperature range that matches the current temperature is inoculated. i The corresponding growth temperature range continues to ferment and reaches the next sludge fermentation agent Y i+1 The corresponding growth temperature range median T i+1-M , inoculate the next sludge fermentation agent Y i+1 Because when the sludge fermentation agent is inoculated for the first time, the size of each colony in the municipal sludge is relatively small, which will not affect the growth and reproduction of the fermentation microorganisms of the sludge fermentation agent inoculated for the first time.

[0047] It should be noted that the current sludge fermentation agent Y i The fermentation microorganisms will gradually decline when they just exceed their growth temperature range, but they will still serve as the main fermentation bacteria. If the next sludge fermentation agent Y is directly added at this time i+1 , current sludge fermentation agent Y i The fermentation microorganisms will have a great impact on the next sludge fermentation agent Y due to the large colony i+1 The fermentation microorganisms survive and squeeze out, resulting in the next sludge fermentation agent Y i+1 It is difficult for the fermentation microorganisms to grow and reproduce in the first place, and even the number of colonies will decrease. Under normal circumstances, the temperature in the fermentation tower reaches the next sludge fermentation agent Y i+1 The corresponding growth temperature range median T i+1-M When the current sludge fermentation agent Y i The fermentation microbial colony declines to the point where it is difficult to affect the next sludge fermentation agent Y i+1 Therefore, the current sludge fermentation agent Y i The fermentation microorganisms in the corresponding growth temperature range of the upper limit temperature to the next sludge fermentation agent Y i+1 The corresponding growth temperature range median T i+1-M After the colony declines, add the next sludge fermentation agent Y i+1 , can effectively reduce the current sludge fermentation agent Y i The fermentation microorganisms and the next sludge fermentation agent Y i+1 competition of fermentation microorganisms to ensure the next sludge fermentation agent Y i+1 The fermentation microorganisms can grow and reproduce normally after inoculation, thereby accelerating the fermentation efficiency.

[0048] Step S104: in response to the fact that the colony density of the fermentation microorganisms corresponding to the last added sludge fermentation agent reaches a preset requirement, the municipal sludge is taken out for granulation to obtain biomass fuel pellets.

[0049] It should be noted that the fermentation microbial colony density corresponding to the last added sludge fermentation agent meets a preset requirement, which can be a colony density standard established based on the organic matter content in the municipal sludge. Therefore, reaching the required density indicates that the organic matter content in the municipal sludge has been consumed to a preset level, and fermentation is considered complete, and the municipal sludge can be removed.

[0050] Optionally, the density analysis samples of municipal sludge are collected from the fermentation tower at regular intervals, and the colony density of the density analysis samples is measured to obtain the colony density of the fermentation microorganisms corresponding to the sludge fermentation agent added last.

[0051] Furthermore, the regularly obtained fermentation microorganism colony density can be plotted as a time-density function to record data and facilitate subsequent analysis.

[0052] Optionally, after the municipal sludge is fed into the fermentation tower, the method further comprises:

[0053] A blower is used to introduce air from the bottom and / or side of the fermentation tower to ensure that the oxygen content at each position in the fermentation tower is maintained at 5-15v / v%.

[0054] The introduction of air can effectively prevent a large reduction in oxygen content, causing fermentation to transform from aerobic to anaerobic state and a sharp drop in temperature, resulting in the formation of smelly intermediates.

[0055] Optionally, municipal sludge is taken out for pelletizing to obtain biomass fuel pellets, including:

[0056] Take out the fermented municipal sludge and crush it into 60-80 mesh;

[0057] Add combustion aid to the crushed municipal sludge and mix well;

[0058] The evenly mixed municipal sludge is fed into an extruder to obtain biomass fuel pellets.

[0059] Optionally, after removing municipal sludge and pelletizing to obtain biomass fuel pellets, the method further comprises:

[0060] The biomass fuel particles are dried to reduce the moisture content in the biomass fuel particles and improve the combustion performance of the biomass fuel particles.

[0061] Optionally, before feeding the municipal sludge into the fermentation tower, the method further comprises:

[0062] Desulfurization of municipal sewage sludge can reduce the sulfur content of municipal sewage sludge.

[0063] The combustion of sulfur compounds produces harmful gases that harm the environment. Therefore, municipal sludge needs to be desulfurized.

[0064] Optionally, before adding sawdust according to the moisture content of the municipal sludge to maintain the moisture content of the municipal sludge at 45-60%, the method further comprises:

[0065] Carbonize the sawdust to reduce the organic matter content in the sawdust.

[0066] It should be noted that the sawdust should be carbonized in advance to reduce the organic matter content in the sawdust and avoid excessive decomposition of the sawdust by fermentation microorganisms, which would reduce the calorific value.

[0067] In a specific embodiment:

[0068] For the convenience of explanation, the temperature range of 10-70℃ is divided into four culture temperature intervals, namely [10℃, 25℃], [25℃, 40℃], [40℃, 55℃] and [55℃, 70℃]. Municipal sludge is cultured in culture vessels corresponding to these four culture temperature intervals to obtain sludge fermentation agents in these four culture temperature intervals.

[0069] After the municipal sludge is put into the fermentation tower and the moisture content is adjusted, the temperature in the fermentation tower is 20℃, and the corresponding sludge fermentation agent of [10℃, 25℃] is inoculated;

[0070] The temperature in the fermentation tower continues to rise. When the temperature in the fermentation tower is between 25℃ and 32.5℃, although the fermentation microorganisms of the sludge fermentation agent corresponding to [10℃, 25℃] are not in the suitable growth temperature range, their colony count is still relatively large, and they will compete with and affect the sludge fermentation agent corresponding to [25℃, 40℃]. When it reaches 32.5℃, the fermentation microorganism colony count of the sludge fermentation agent corresponding to [10℃, 25°C] declines, making it difficult to affect the sludge fermentation agent corresponding to [25℃, 40℃]. At this time, the sludge corresponding to [25℃, 40℃] is inoculated for fermentation.

[0071] The temperature in the fermentation tower continues to rise. Similarly, when it reaches 47.5℃, the fermentation microbial colony of the sludge fermentation agent corresponding to [25℃, 40℃] declines and it is difficult to affect the sludge fermentation agent corresponding to [40℃, 55℃]. At this time, the sludge fermentation corresponding to [40℃, 55℃] is inoculated.

[0072] The temperature in the fermentation tower continues to rise. Similarly, when it reaches 62.5℃, the fermentation microbial colony of the sludge fermentation agent corresponding to [40℃, 55℃] declines and it is difficult to affect the sludge fermentation agent corresponding to [55℃, 70℃]. At this time, the sludge fermentation corresponding to [55℃, 70℃] is inoculated.

[0073] When the colony density of the fermentation microorganisms in the sludge fermentation agent corresponding to [55°C, 70°C] reaches the preset requirement, the fermentation is determined to be complete. The municipal sludge is removed for granulation.

[0074] The embodiment of the present invention responds to the temperature in the fermentation tower exceeding the current sludge fermentation agent Y i The corresponding growth temperature range and continue to ferment in the colony decline period (in the colony decline period, the current sludge fermentation agent Y i The number of fermentation microorganisms gradually decreases, but because its number is still relatively large, it still serves as the main fermentation microorganism for municipal sludge fermentation) and reaches the next sludge fermentation agent Y i+1 The corresponding growth temperature range median T i+1-M , inoculate the next sludge fermentation agent Y i+1 The present invention embodiment is based on the current sludge fermentation agent Yi The fermentation microorganisms in the corresponding growth temperature range of the upper limit temperature to the next sludge fermentation agent Y i+1 The corresponding growth temperature range median T i+1-M After the colony declines, add the next sludge fermentation agent Y i+1 , can effectively reduce the current sludge fermentation agent Y i The fermentation microorganisms and the next sludge fermentation agent Y i+1 competition of fermentation microorganisms to ensure the next sludge fermentation agent Y i+1 The fermentation microorganisms can grow and reproduce normally after inoculation, thereby accelerating the fermentation efficiency. In the embodiment of the present invention, a municipal sludge sample is divided into I parts, and I part of the municipal sludge sample is added to I culture vessels respectively. The culture temperature of I culture vessels is controlled to correspond to I culture temperature intervals divided into 10-75°C [T i-L ,T i-H ], in response to the colony density of the fermentation microorganisms in the culture vessel reaching a preset density, a sludge fermentation agent Y is obtained. i . The embodiment of the present invention uses microorganisms cultured in the municipal sludge itself as a fermentation agent. Compared with external fermentation agents, it can adapt to the municipal sludge environment faster, grow and reproduce faster during the fermentation process to decompose organic matter in the municipal sludge. The embodiment of the present invention puts the municipal sludge into the fermentation tower, and adds sawdust according to the water content of the municipal sludge to keep the water content of the municipal sludge at 45-60%. The embodiment of the present invention adjusts the water content of the municipal sludge by sawdust, and can improve the calorific value of the product biomass fuel particles while ensuring the effective regulation of the water content. The embodiment of the present invention inoculates the sludge fermentation agent Y according to the temperature in the fermentation tower. i . The fermentation agent of the embodiment of the present invention is inoculated in different temperature sections, which ensures that the fermentation microorganisms in different temperature sections can form a larger colony scale for fermentation at the first time of inoculation, while the prior art can only wait for a certain period of time after reaching the temperature section for the fermentation microorganisms in the temperature section to form a larger colony scale, thereby accelerating the fermentation efficiency. The embodiment of the present invention can accurately and effectively judge whether the fermentation is completed by the colony density of the fermentation microorganism corresponding to the last added sludge fermentation agent reaches the preset requirements. The embodiment of the present invention can carbonize the sawdust in advance to reduce the organic matter content in the sawdust and avoid the situation where the sawdust is also excessively decomposed by the fermentation microorganisms and the calorific value is reduced. In summary, the embodiment of the present invention achieves the purpose of improving the preparation efficiency of biomass fuel particles by accelerating the fermentation step in the process of preparing biomass fuel particles.

[0075] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0076] Each embodiment in this specification is described in a related manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiment is generally similar to the method embodiment, so the description is relatively simple. For related parts, refer to the description of the method embodiment.

[0077] The above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A method for preparing sludge biomass fuel pellets by mixing municipal sludge with sawdust, characterized in that: The method comprises: Take a municipal sludge sample and divide it into I parts. Add I parts of the municipal sludge sample into I culture vessels respectively. Control the culture temperature of I culture vessels to correspond to I culture temperature intervals divided into 10-75°C [T i-L ,T i-H ], in response to the colony density of the fermentation microorganisms in the culture vessel reaching a preset density, obtaining sludge fermentation agent Y i ; Wherein, i is an integer number of the culture temperature intervals in ascending order and 0<i≤I, the sludge fermentation agent Y i The corresponding growth temperature interval is the i-th culture temperature interval [T i-L ,T i-H ]; Putting the municipal sludge into a fermentation tower, and adding sawdust according to the water content of the municipal sludge, so that the water content of the municipal sludge is maintained at 45-60%; According to the temperature in the fermentation tower, the sludge fermentation agent Y is inoculated. i Wherein, in response to the temperature in the fermentation tower exceeding the current sludge fermentation agent Y i The corresponding growth temperature range and continued fermentation in the colony decline period, and reached the next sludge fermentation agent Y i+1 The corresponding growth temperature range median T i+1-M , inoculate the next sludge fermentation agent Y i+1 ; Wherein, the sludge fermentation agent Y i In the temperature range [T i-H ,T i+1-M ] The fermentation operation period is the colony decline period; In response to the fact that the colony density of the fermentation microorganisms corresponding to the last added sludge fermentation agent reaches a preset requirement, the municipal sludge is taken out for granulation to obtain biomass fuel particles.

2. The method for preparing sludge biomass fuel particles by mixing municipal sludge with sawdust according to claim 1, characterized in that: In response to the colony density of the fermentation microorganisms in the culture vessel reaching a preset density, a sludge fermentation agent Y is obtained. i ,include: In response to the colony density of the fermentation microorganisms in the culture vessel reaching 4×10 8 -6.5×10 8 CFU / ml, it is judged that the fermentation microorganism culture is complete, and the sludge fermentation agent Y is obtained. i ; Among them, the colony density only counts the effective living bacteria.

3. The method for preparing sludge biomass fuel particles by mixing municipal sludge with sawdust according to claim 1, characterized in that: The step of adding sawdust according to the water content of the municipal sludge to maintain the water content of the municipal sludge at 45-60% comprises: detecting the water content of the municipal sludge; Sawdust is added according to the water content of the municipal sludge to keep the water content of the municipal sludge at 45-60%, while ensuring that the calorific value of the biomass fuel particles prepared after the fermentation of the municipal sludge meets the minimum combustion standard.

4. The method for preparing sludge biomass fuel particles by mixing municipal sludge with sawdust according to claim 1, characterized in that: After the municipal sludge is fed into the fermentation tower, the method further comprises: A blower is used to introduce air from the bottom and / or side of the fermentation tower to ensure that the oxygen content at each position in the fermentation tower is maintained at 5-15v / v%.

5. The method for preparing sludge biomass fuel particles by mixing municipal sludge with sawdust according to claim 1, characterized in that: The process of taking out the municipal sludge and granulating it to obtain biomass fuel pellets comprises: Taking out the fermented municipal sludge and crushing it into 60-80 mesh; Add combustion aid to the crushed municipal sludge and mix well; The evenly mixed municipal sludge is fed into an extruder to obtain the biomass fuel particles.

6. The method for preparing sludge biomass fuel particles by mixing municipal sludge with sawdust according to claim 1, characterized in that: After the municipal sludge is taken out and granulated to obtain biomass fuel pellets, the method further comprises: The biomass fuel particles are dried to reduce the moisture content in the biomass fuel particles and improve the combustion performance of the biomass fuel particles.

7. The method for preparing sludge biomass fuel pellets by mixing municipal sludge with sawdust according to claim 1, characterized in that: Before feeding the municipal sludge into the fermentation tower, the method further comprises: The municipal sludge is subjected to desulfurization treatment to reduce the sulfur content of the municipal sludge.

8. The method for preparing sludge biomass fuel pellets by mixing municipal sludge with sawdust according to claim 1, characterized in that: Before adding sawdust according to the water content of the municipal sludge so as to maintain the water content of the municipal sludge at 45-60%, the method further comprises: The sawdust is carbonized to reduce the organic matter content in the sawdust.

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