Biomass gas afterburner switching control system

Abstract

The application discloses a kind of biomass gas afterburning device switching control system, including two groups of biomass gas regulating device, natural gas intake device, blending device and signal processing device, one end of one group of the biomass gas regulating device is communicated with the other end of another group of the biomass gas regulating device by conveying main pipe, each group of the biomass gas regulating device is used to generate biomass gas;Natural gas intake device is connected with the communication end of two groups of the biomass gas regulating device, for conveying natural gas;Blending device is connected with the communication end of two groups of the biomass gas regulating device, for mixing and blending biomass gas and natural gas;Signal processing device is communicatively connected with two groups of biomass gas regulating device, for calculating each signal parameter in biomass gas regulating device, to control biomass gas regulating device to adjust and convey biomass gas, can make each parameter fluctuation in conveying main pipe be within reasonable range, stably realize the blending condition of biomass gas and natural gas.

Description

Technical Field

[0001] This invention relates to the field of biomass energy technology, specifically to a switching control system for a biomass gas combustion supplementation device. Background Technology

[0002] Biomass energy is internationally recognized as a clean, renewable, and high-yield energy source. Because the carbon dioxide emissions from biomass combustion are the same as the carbon dioxide absorbed during its growth, it achieves zero carbon dioxide emissions after combustion. Furthermore, it contains almost no sulfur and has a low nitrogen content, resulting in minimal environmental pollution and effectively alleviating energy shortages. Biomass can be converted into solid, liquid, and gaseous fuels, and can also be developed into various forms of energy, including heat, electricity, and cooling. It also occupies a significant share of the energy end-use market. Its accessibility and ability to meet diverse energy market demands drive the development of clean energy technologies.

[0003] Biomass energy technologies include direct combustion, physicochemical conversion, bioconversion, and vegetable oil technologies. Because direct combustion has low energy efficiency, conversion technologies are generally used to efficiently utilize biomass energy. These conversion technologies include biomass pyrolysis, biomass liquefaction, and biomass gasification. Biomass gasification refers to the process where, under high temperature and oxygen-deficient conditions, pyrolysis produces carbon monoxide, which reacts chemically with a gasification medium (air, oxygen, water vapor, or hydrogen) to produce combustible gases primarily composed of CO, H2, or CH4. As a widely used method of biomass energy utilization, biomass gasification is more environmentally friendly and has a higher resource utilization rate compared to direct combustion. Furthermore, biomass gasification is highly adaptable to different feedstocks, with most types of feedstock suitable for conversion. Besides being used as fuel itself, biomass gas can also be co-fired with other fuels such as coal and natural gas to improve overall energy efficiency.

[0004] Due to its high calorific value and environmentally friendly combustion products, most roasting furnaces currently use natural gas as fuel. However, the high price of natural gas fuel leads to high operating costs for roasting furnaces and can result in excessive nitrogen oxide emissions. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the above-mentioned background technology and provide a switching control system for a biomass gas combustion device, which can keep the fluctuations of various parameters in the main pipeline within a reasonable range and stably realize the co-firing of biomass gas and natural gas.

[0006] Firstly, a switching control system for a biomass gas afterburner is provided, comprising:

[0007] Two sets of biomass gas regulating devices, one end of one set of biomass gas regulating devices is connected to one end of the other set of biomass gas regulating devices through a main pipeline, and each set of biomass gas regulating devices is used to generate biomass gas.

[0008] A natural gas intake device is connected to the connecting end of the two sets of biomass gas regulating devices and is used to transport natural gas;

[0009] A co-firing device, connected to the connecting ends of the two sets of biomass gas conditioning devices, is used to mix and co-firing biomass gas with natural gas; and,

[0010] The signal processing device is communicatively connected to two sets of biomass gas regulating devices. It is used to calculate various signal parameters in the biomass gas regulating devices in order to control the biomass gas regulating devices to regulate and deliver biomass gas.

[0011] In some embodiments, each group of biomass gas regulating devices includes a biomass gasifier, a bag filter, a booster fan, a first measuring instrument, a venting regulating valve, a biomass gas regulating valve, a check valve, and a second measuring instrument, which are sequentially connected through the conveying main pipe.

[0012] In some embodiments, the first measuring instrument includes a first fixed zirconia O2 analyzer, a first vortex flow meter, and a first temperature instrument connected in sequence.

[0013] The second measuring instrument includes a second fixed zirconia O2 analyzer, a second vortex flow meter, and a second temperature instrument connected in sequence.

[0014] In some embodiments, the co-firing device includes a roasting furnace combustion chamber connected to the conveying main pipe, and a separator connected to the roasting furnace combustion chamber.

[0015] In some embodiments, the signal processing apparatus is further configured to,

[0016] Calculate the rate of change of biomass gas injection, and adjust the rate of change of biomass gas injection within a first threshold range by controlling the biomass gas regulating device.

[0017] Calculate the rate of change of the booster fan outlet flow rate, and adjust the biomass gas regulating device to adjust the rate of change of the booster fan outlet flow rate within the second threshold range;

[0018] Calculate the rate of change of biomass gas flow rate, and control the biomass gas regulating device to adjust the rate of change of biomass gas flow rate within the third threshold range;

[0019] The rate of change of oxygen content in the biomass gas transmission main pipe is calculated, and the biomass gas regulating device is used to regulate the rate of change of oxygen content in the biomass gas transmission main pipe within the fourth threshold range.

[0020] In some embodiments, the formula for calculating the biomass gas injection change rate η is as follows:

[0021]

[0022] Among them, the volumetric flow rate Q of the biomass gas transmission main pipeline under standard conditions YF for:

[0023]

[0024] In the formula, P 实际 The measured pressure of the biomass gas transmission main pipeline; T 实际 Q represents the measured temperature of the biomass gas transmission main pipeline; 实际 Q represents the measured flow rate of the biomass gas transmission main pipeline; XH This represents the volumetric flow rate at the outlet of the booster fan under standard conditions.

[0025] In some embodiments, the rate of change of the booster fan outlet flow rate Δδ S The calculation formula is as follows:

[0026]

[0027] In the formula, The volumetric flow rate at the outlet of the booster fan after the (n+1)th adjustment under standard conditions; Let n be the volumetric flow rate at the outlet of the booster fan after the nth adjustment under standard conditions, where n is the number of adjustments.

[0028] In some embodiments, the formula for calculating the rate of change of biomass gas flow rate is as follows:

[0029]

[0030] In the formula, Q′ K This refers to the volumetric flow rate injected into the main pipeline during biomass gas conditioning under standard conditions. This represents the volumetric flow rate of the gas produced by the biomass gasifier under standard conditions.

[0031] In some embodiments, the rate of change of oxygen content ΔP in the biomass gas transmission header is... k The calculation formula is as follows:

[0032] ΔP k =P k (n+1)-P k (n-τ2);

[0033] In the formula, P k τk represents the k-th measurement of oxygen content in the biomass gas transmission main pipe; n represents the number of adjustments; and τ2 represents the lead-in time constant of the flue gas composition.

[0034] Compared with existing technologies, this invention generates biomass gas by setting up a biomass gas regulating device, and then mixes and co-fires the biomass gas with natural gas using a co-firing device. This allows biomass gas to replace a portion of the natural gas in the roasting furnace, offering advantages such as reduced operating costs, increased operating efficiency, and reduced nitrogen oxide emissions. Furthermore, because natural gas and biomass gas differ in composition and calorific value, a signal processing device calculates various signal parameters in the biomass gas regulating device to control the biomass gas supply. This ensures that fluctuations in parameters within the main supply pipeline remain within a reasonable range, stably achieving the co-firing of biomass gas and natural gas. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the switching control system of the biomass gas combustion device of the present invention;

[0036] Figure 2 This is a schematic diagram of the biomass gas regulation process of the present invention.

[0037] Icon labels:

[0038] 100. Biomass gasifier; 200. Bag filter; 300. Booster fan; 400. First measuring instrument; 500. Vent control valve; 600. Biomass gas control valve; 700. Check valve; 800. Second measuring instrument; 900. Blending device. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] See Figure 1 As shown, an embodiment of the present invention provides a switching control system for a biomass gas afterburner, comprising:

[0041] Two sets of biomass gas regulating devices, one end of one set of biomass gas regulating devices is connected to one end of the other set of biomass gas regulating devices through a main pipeline, and each set of biomass gas regulating devices is used to generate biomass gas.

[0042] A natural gas intake device is connected to the connecting end of the two sets of biomass gas regulating devices and is used to transport natural gas;

[0043] The co-firing device 900 is connected to the connecting end of the two sets of biomass gas regulating devices and is used to mix and co-firing biomass gas with natural gas.

[0044] The signal processing device is communicatively connected to two sets of biomass gas regulating devices. It is used to calculate various signal parameters in the biomass gas regulating devices in order to control the biomass gas regulating devices to regulate and deliver biomass gas.

[0045] Specifically, in this embodiment, due to the high calorific value of natural gas and the environmentally friendly nature of its combustion products, most roasting furnaces currently use natural gas as fuel. However, the high price of natural gas fuel results in high operating costs for roasting furnaces and the possibility of excessive nitrogen oxide emissions.

[0046] Therefore, this invention generates biomass gas by setting up a biomass gas regulating device, and then mixes and co-fires the biomass gas with natural gas using a co-firing device 900. This allows biomass gas to replace a portion of the natural gas in the roasting furnace, offering advantages such as reduced operating costs, increased operating efficiency, and reduced nitrogen oxide emissions. Furthermore, since natural gas and biomass gas differ in composition and calorific value, a signal processing device calculates various signal parameters in the biomass gas regulating device to control the biomass gas supply. This ensures that fluctuations in parameters within the main supply pipeline remain within a reasonable range, stably achieving the co-firing of biomass gas and natural gas.

[0047] Optionally, each set of biomass gas regulating devices includes a biomass gasifier 100, a bag filter 200, a booster fan 300, a first measuring instrument 400, a vent regulating valve 500, a biomass gas regulating valve 600, a one-way valve 700, and a second measuring instrument 800, which are connected sequentially through the conveying main pipe.

[0048] Optionally, the first measuring instrument 400 includes a first fixed zirconia O2 analyzer, a first vortex flow meter, and a first temperature instrument connected in sequence.

[0049] The second measuring instrument 800 includes a second fixed zirconia O2 analyzer, a second vortex flow meter, and a second temperature instrument connected in sequence.

[0050] Optionally, the co-firing device 900 includes a roasting furnace combustion chamber connected to the conveying main pipe, and a separator connected to the roasting furnace combustion chamber.

[0051] Optionally, the signal processing device is further used to,

[0052] Calculate the rate of change of biomass gas injection, and adjust the rate of change of biomass gas injection within a first threshold range by controlling the biomass gas regulating device.

[0053] Calculate the rate of change of the booster fan outlet flow rate, and adjust the biomass gas regulating device to adjust the rate of change of the booster fan outlet flow rate within the second threshold range;

[0054] Calculate the rate of change of biomass gas flow rate, and control the biomass gas regulating device to adjust the rate of change of biomass gas flow rate within the third threshold range;

[0055] The rate of change of oxygen content in the biomass gas transmission main pipe is calculated, and the biomass gas regulating device is used to regulate the rate of change of oxygen content in the biomass gas transmission main pipe within the fourth threshold range.

[0056] Specifically, in this embodiment, the various signal parameters in the biomass gas regulating device include the biomass gas injection change rate, the booster fan outlet flow rate change rate, the biomass gas flow rate change rate, and the oxygen content change rate in the biomass gas transmission main pipe. Therefore, by adjusting the above signal parameters and controlling them within a reasonable range, the co-firing of biomass gas and natural gas can be stably achieved.

[0057] The switching control signals are divided into "+" and "-". "+" indicates the injection of biomass gas, and "-" indicates the removal of biomass gas. The process of injecting biomass gas ("+") and removing biomass gas ("-") is carried out gradually. In order to avoid large disturbances to the main pipe parameters, multiple small openings and small flow rates are required for injection and removal, i.e., multiple fine adjustments to each valve. When the switching signal "+" is input, the biomass gas regulating valve is opened, and the vent regulating valve is closed at the same time, until all the biomass gas from the biomass gasifier is incorporated into the biomass gas delivery main pipe. The biomass gas injection rate η is a function of time, and its rate of change must be within the first threshold range—that is, less than +0.8% / min. The switching change of "-" is the opposite of "+". When the switching signal "-" is input, the biomass regulating valve is gradually closed first, and then the vent regulating valve is gradually opened. The rate of change of η is less than -0.8% / min.

[0058] When the switching control signal is input "+", first appropriately increase the frequency of the gasifier's booster fan so that its pressure is slightly higher than the pressure of the main delivery pipe. At this time, open the biomass gas regulating valve and simultaneously close the vent regulating valve until all the biomass gas from this gasifier is connected to the biomass gas main pipe. When the switching is complete, the biomass gas regulating valve is fully open and the vent regulating valve is fully closed. The entire gas connection process takes approximately 30 minutes.

[0059] Optionally, the formula for calculating the biomass gas injection change rate η is as follows:

[0060]

[0061] Among them, the volumetric flow rate Q of the biomass gas transmission main pipeline under standard conditions YF for:

[0062]

[0063] In the formula, P 实际 The measured pressure of the biomass gas transmission main pipeline; T 实际 Q represents the measured temperature of the biomass gas transmission main pipeline; 实际 Q represents the measured flow rate of the biomass gas transmission main pipeline; XH This represents the volumetric flow rate at the outlet of the booster fan under standard conditions.

[0064] Optional, the rate of change of the booster fan outlet flow rate Δδ S The calculation formula is as follows:

[0065]

[0066] In the formula, The volumetric flow rate at the outlet of the booster fan after the (n+1)th adjustment under standard conditions; Let n be the volumetric flow rate at the outlet of the booster fan after the nth adjustment under standard conditions, where n is the number of adjustments.

[0067] Therefore, the rate of change of the booster fan outlet flow is calculated, and the biomass gas regulating device is used to adjust the rate of change of the booster fan outlet flow within the second threshold range - i.e., less than ±5% / min.

[0068] Optionally, the formula for calculating the rate of change of biomass gas flow rate is as follows:

[0069]

[0070] In the formula, Q' K This refers to the volumetric flow rate injected into the main pipeline during biomass gas conditioning under standard conditions. This represents the volumetric flow rate of the gas produced by the biomass gasifier under standard conditions.

[0071] Specifically, in this embodiment, the biomass gas flow rate change rate is calculated to control the biomass gas regulating device to adjust the biomass gas flow rate change rate within the third threshold range; specifically, in order to maintain the stability of gas delivery during the regulation process, the biomass gas flow rate change rate (main pipe flow rate) is controlled to be less than ±1% / min after the first regulation, and the main pipe flow rate change is less than ±2% / min after the second to nth regulation.

[0072] For example, the rate of change of biomass gas flow rate during the 10 adjustment processes were 0.65% / min, 0.71% / min, 0.84% / min, 0.89% / min, 0.96% / min, 1.11% / min, 1.23% / min, 1.16% / min, 1.27% / min, and 0.77% / min, all less than ±2% / min.

[0073] Optionally, the rate of change of oxygen content ΔP in the biomass gas transmission main pipeline.k The calculation formula is as follows:

[0074] ΔP k =P k (n+1)-P k (n-τ2);

[0075] In the formula, P k τk represents the k-th measurement of oxygen content in the biomass gas transmission main pipe; n represents the number of adjustments; and τ2 represents the lead-in time constant of the flue gas composition.

[0076] Specifically, in this embodiment, during the adjustment process, the opening of the biomass gas regulating valve can be adjusted by measuring the oxygen content. To ensure system safety, the oxygen content in the biomass gas transmission main pipe should be kept below 3%, and the oxygen content change rate should be controlled within the fourth threshold range - that is, less than ±0.1% / min.

[0077] For example, the oxygen content in the corresponding 10 adjustment processes was 2.15%, 2.08%, 2.01%, 1.92%, 1.90%, 1.82%, 1.73%, 2.08%, 2.15%, and 2.66%, all less than 3%; the corresponding oxygen content change rates were 0.03% / min, 0.02% / min, 0.02% / min, 0.04% / min, 0.02% / min, 0.06% / min, 0.08% / min, 0.04% / min, 0.05% / min, and 0.05% / min, all less than ±0.1% / min.

[0078] It should be noted that the outlet pressure of the booster blower of one biomass gasifier is 15 kPa, which is connected to the main transmission pipeline. The biomass gas transmission pipeline pressure is 11.5 kPa and the temperature is 405°C. When the other biomass gasifier is connected to the main pipeline, its booster blower pressure is adjusted to 15.5 kPa (slightly higher than the main pipeline pressure) and the temperature is 410°C. At this time, the vent valve is gradually closed and the biomass gas regulating valve is slowly opened, so that the pressure and temperature in the biomass gas transmission pipeline are basically maintained within the normal range.

[0079] Therefore, by monitoring the temperature of the gas at the gasifier outlet in real time with temperature instruments, the temperature of the gas before and after entering the main pipeline is not lower than 400°C, thereby reducing tar condensation and slagging on the pipe wall.

[0080] See also Figure 2As shown, therefore, under any adjustment condition ("+" switching to "-", or "-" switching to "+"), the present invention sets the biomass gas injection rate to less than ±0.8% / min, the change in the booster fan outlet flow rate to less than ±5% / min, the change in the main pipe flow rate after the first adjustment to less than ±1% / min, the change rate of biomass gas flow rate after the second to nth adjustments to less than ±2% / min, the oxygen content in the main pipe to be controlled below 3%, the temperature of the fuel gas before and after entering the main pipe to be no less than 400℃, and the temperature change rate at any detection point at any time to less than ±5℃ / min. Therefore, the fluctuations of various parameters in the main pipe can be kept within a reasonable range, stably achieving the co-firing of biomass gas and natural gas.

[0081] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0082] It should be noted that, in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0083] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A switching control system for a biomass gas afterburner, characterized in that, include: Two sets of biomass gas regulating devices, one end of one set of biomass gas regulating devices is connected to one end of the other set of biomass gas regulating devices through a main pipeline, and each set of biomass gas regulating devices is used to generate biomass gas. A natural gas intake device is connected to the connecting end of the two sets of biomass gas regulating devices and is used to transport natural gas; The co-firing device is connected to the connecting end of the two sets of biomass gas conditioning devices and is used to mix and co-firing biomass gas with natural gas. as well as, The signal processing device is communicatively connected to two sets of biomass gas regulating devices and is used to calculate various signal parameters in the biomass gas regulating devices in order to control the biomass gas regulating devices to regulate the delivery of biomass gas. Each set of biomass gas regulating devices includes a biomass gasifier, a bag filter, a booster fan, a first measuring instrument, a vent regulating valve, a biomass gas regulating valve, a check valve, and a second measuring instrument, which are connected sequentially through the conveying main pipe. The first measuring instrument includes a first fixed zirconia O2 analyzer, a first vortex flow meter, and a first temperature instrument connected in sequence; The second measuring instrument includes a second fixed zirconia O2 analyzer, a second vortex flow meter, and a second temperature instrument connected in sequence; The signal processing device is also used for, Calculate the rate of change of biomass gas injection, and adjust the rate of change of biomass gas injection within a first threshold range by controlling the biomass gas regulating device. Calculate the rate of change of the booster fan outlet flow rate, and adjust the biomass gas regulating device to adjust the rate of change of the booster fan outlet flow rate within the second threshold range; Calculate the rate of change of biomass gas flow rate, and control the biomass gas regulating device to adjust the rate of change of biomass gas flow rate within the third threshold range; Calculate the rate of change of oxygen content in the biomass gas transmission main pipe, so as to control the biomass gas regulating device to adjust the rate of change of oxygen content in the biomass gas transmission main pipe within the fourth threshold range; The formula for calculating the rate of change of biomass gas injection η is as follows: ； Among them, the volumetric flow rate Q of the biomass gas transmission main pipeline under standard conditions YF for: ； In the formula, P 实际 The measured pressure of the biomass gas transmission main pipeline; T 实际 Q represents the measured temperature of the biomass gas transmission main pipeline; 实际 Q represents the measured flow rate of the biomass gas transmission main pipeline; XH This represents the volumetric flow rate at the outlet of the booster fan under standard conditions.

2. The switching control system for the biomass gas afterburning device as described in claim 1, characterized in that, The co-firing device includes a roasting furnace combustion chamber connected to the conveying main pipe, and a separator connected to the roasting furnace combustion chamber.

3. The switching control system for the biomass gas afterburner as described in claim 1, characterized in that, Rate of change of outlet flow of booster fan Δδ S The calculation formula is as follows: ； In the formula, This represents the volumetric flow rate at the outlet of the booster fan after the (n+1)th adjustment under standard conditions. Let n be the volumetric flow rate at the outlet of the booster fan after the nth adjustment under standard conditions, where n is the number of adjustments.

4. The switching control system for the biomass gas afterburner as described in claim 1, characterized in that, The formula for calculating the rate of change of biomass gas flow rate is as follows: ； In the formula, This refers to the volumetric flow rate injected into the main pipeline during biomass gas conditioning under standard conditions. This represents the volumetric flow rate of the gas produced by the biomass gasifier under standard conditions.

5. The switching control system for the biomass gas afterburning device as described in claim 1, characterized in that, Oxygen content change rate in biomass gas transmission main pipeline The calculation formula is as follows: (n+1) (n ); In the formula, represents the kth measurement of oxygen content in the biomass gas transmission main pipeline; n represents the number of adjustments. is the lead time constant of the flue gas composition.

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