A high voltage power failure control method for an energy recovery device for biological fermentation

Abstract

The invention discloses a high voltage power failure control method for an energy recovery device for biological fermentation: step 1, obtaining compressor power at different operating points; step 2, selecting a steam turbine to obtain the rated power of the steam turbine; step 3, calculating the generator power at different operating points; step 4, respectively calculating the generator current at different operating points; step 5, assuming that the generator power is zero, dividing the steam turbine power at each operating point by its rated power, and obtaining the valve position opening of the regulating steam valve at the corresponding operating point; step 6, obtaining the relationship between the generator power at the moment of high voltage power failure and the valve position opening when the power is 0; step 7, obtaining the relationship between the generator current and the valve position opening; step 8, correcting the relationship; step 9, the unit controls the steam turbine to adjust the valve position opening of the steam valve. When the high voltage power fails, the invention controls the steam turbine to adjust the valve position opening of the steam valve, so that the generator power quickly becomes 0, thereby avoiding the occurrence of overspeed operation of the unit or even runaway accidents.

Description

Technical Field

[0001] The invention belongs to the technical field of biological fermentation and relates to a high-voltage power-off control method for a three-in-one energy recovery unit. Background Art

[0002] In the biological fermentation industry, users usually use steam turbines to drive compressor units to meet the compressed air needs of fermentation. Figure 1 As shown in the figure, the fermentation industry uses steam-driven compressor units. In addition, the surplus steam generated by the boiler is usually used by users to generate electricity, so users will also use steam turbine generator sets. Figure 2 As shown, steam turbine generator set for fermentation industry.

[0003] At present, some users have adopted a new three-in-one energy recovery unit to meet the compressed air used for biological fermentation, and the excess energy is directly used for power generation. Figure 3 The three-in-one energy recovery unit shown in the figure comprises a compressor 1, a steam turbine 2, a gear box 3 and a generator 4, wherein the exhaust side of the steam turbine 2 is connected to the compressor 1, the intake side of the steam turbine 2 is connected to the generator 4 through the gear box 3, and a regulating steam valve 5 is provided on the steam inlet pipeline of the steam turbine. Figure 4 As shown in the figure. The advantages of this new three-in-one energy recovery unit are: (1) The unit is simple and flexible to operate. It can adjust the fan drive and power generation in real time according to the steam supply and distribution, so as to maintain the optimal and most efficient use of factory steam. (2) One set of units can realize the compression process gas supply of the axial compressor and the surplus steam power generation function at the same time, reducing the customer's equipment investment. (3) The automatic control system and electronic control system are merged and simplified, and the lubricating oil station and auxiliary machine system are integrated to reduce the unit configuration and the unit infrastructure cost.

[0004] Compared with the combination of traditional steam-driven compressor units and steam turbine generator units, the advantages of a three-in-one energy recovery unit are obvious. However, there is a problem in the control of the unit that needs to be solved urgently. When the unit is operating normally, if the system high voltage suddenly loses power, the generator will be quickly disconnected from the power grid. According to the normal control method of the unit, that is, the fail-safe control idea, the unit should be interlocked and shut down at this time. However, users will not agree with such a control method. This is because in the entire biological fermentation system, the compressor needs to continuously provide compressed air to the subsequent fermentation tank. Once the unit is shut down, the compressor will not be able to provide compressed air to the fermentation tank, causing the fermentation tank to be "stifled" and even the bacteria to die due to lack of oxygen. If the unit is not interlocked and shut down at this time, the excess energy of the steam turbine in addition to dragging the compressor will cause the unit to run at an overspeed, which will cause the compressor and steam turbine to overspeed in a short period of time, which may cause a unit accident. Summary of the invention

[0005] The purpose of the present invention is to provide a high voltage power failure control method for a three-in-one energy recovery unit for biological fermentation, so as to solve the problem of accidents caused by overspeeding of the existing energy recovery unit due to sudden high voltage power failure.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A method for controlling high voltage power failure of an energy recovery device for biological fermentation, comprising the following steps:

[0008] Step 1, calculating the compressor power according to the input parameters of the compressor at different operating points, and obtaining the compressor power at different operating points respectively;

[0009] Step 2, selecting a steam turbine according to the steam turbine inlet parameters to obtain the rated power of the steam turbine;

[0010] Step 3, subtracting the compressor power at different operating points from the rated power of the steam turbine to obtain the generator power at different operating points;

[0011] Step 4, calculating the generator current at different operating points according to the generator power at different operating points;

[0012] Step 5, assuming that the generator power is zero, the turbine power at each operating point is divided by the rated power of the turbine to obtain the valve position opening of the turbine regulating steam valve at the corresponding operating point; wherein, when the generator power is zero, the turbine power at each operating point corresponds to the compressor power at each operating point calculated in step 1;

[0013] Step 6, divide the steam turbine power by the valve position opening of the regulating steam valve to obtain the linear relationship coefficient between the steam turbine power and the regulating steam valve position opening corresponding to each operating point, average the linear relationship coefficients of all operating points to obtain the final linear relationship coefficient K, and thus obtain the relationship between the steam turbine power P3 and the regulating steam valve position opening x when the generator power is zero: P3 = Kx; at this time, the compressor power P2 = Kx, then the relationship between the generator power at the moment of high-voltage power failure and the steam turbine regulating steam valve position opening corresponding to the generator power being 0 is P1 = K(100-x);

[0014] Step 7: Combine the generator power P1=K(100-x) obtained in step 6 with P1=3 1 / 2 cosφ·U·I, and the relationship between the generator current I at the moment of high-voltage power failure and the valve position opening x of the steam turbine regulating valve corresponding to the generator current being 0 is obtained: I=T1(100-x). Let the generator current be y, and the relationship between the generator current y at the moment of high-voltage power failure and the valve position opening x of the steam turbine regulating valve corresponding to the generator current being 0 is obtained: y=T1(100-x);

[0015] Step 8, taking at least 5 compressor power values ​​within the compressor power range covered by the above-mentioned multiple operating points as new compressor power values ​​at different operating points; calculating the generator power at new different operating points in the same manner as steps 3 and 4, and then obtaining the generator current; dividing the turbine power at each operating point by the rated power of the turbine to obtain the valve position opening of the turbine regulating steam valve at the corresponding operating point when the generator power is zero, and the turbine power at this time is the compressor power value obtained in step 8.

[0016] Substitute the generator current I at each operating point and the valve position opening x of the steam turbine regulating valve when the generator current is 0 into I=T2(100-x) to obtain the parameter T2 value corresponding to each operating point. Compare these five parameter T2 values ​​with the parameter T1 value in the relationship obtained in step 7. If the difference is greater than 10%, delete the parameter T2 value of the corresponding operating point. Average all parameter T2 values ​​with a difference of no more than 10% to obtain the final parameter T3 value. Replace the parameter T1 value in the relationship obtained in step 7 with the final parameter T3 value to obtain the relationship y=T1(100-x) between the corrected generator current y at the moment of high-voltage power failure and the valve position opening x of the steam turbine regulating valve when the generator current is 0.

[0017] Step 9, the unit control system monitors the circuit breaker in real time. When the high voltage power of the grid is cut off, the circuit breaker will be detected to be open. The unit control system substitutes the generator current value at this moment into the relationship obtained in step 8, calculates the opening value of the turbine regulating steam valve when the generator current is 0, and controls the opening of the turbine regulating steam valve to be adjusted to the opening value obtained in this calculation.

[0018] Furthermore, in step 1, the input parameters of the compressor include intake pressure, intake temperature, and intake flow rate.

[0019] Furthermore, in step 1, the number of operating points is 9.

[0020] Furthermore, in step 2, the turbine inlet parameters include inlet steam pressure, temperature and flow rate.

[0021] Furthermore, in step 4, the calculation formula of the generator current is as follows:

[0022] P1=3 1 / 2 cosφ·U·I

[0023] Among them, cosφ is the power factor, U is the voltage, and I is the generator current.

[0024] Furthermore, in step 8, the five compressor power values ​​are selected as: two values ​​after rounding of the minimum and maximum values ​​within the compressor power range at different operating points obtained in step 1 and at least three values ​​in between.

[0025] Compared with the prior art, the method of the present invention has the following beneficial effects:

[0026] 1. The present invention links the generator power with the valve position opening of the steam turbine regulating valve. When the high voltage power is cut off, the generator power is quickly changed to 0 power by controlling the valve position opening of the steam turbine regulating valve, thereby avoiding overspeed operation of the unit or even runaway accidents.

[0027] 2. Through mathematical derivation, we found the functional relationship between the generator current at the moment of high-voltage power failure and the corresponding turbine regulating valve position opening when the generator current is 0. We programmed it into the unit control system, so that the valve position opening of the turbine regulating valve can be accurately controlled to accurately reduce the generator power to 0 power.

[0028] 3. By taking more than 5 operating points for on-site debugging and verification, the functional relationship between the generator current at the moment of high-voltage power failure and the corresponding steam turbine regulating steam valve position opening when the generator current is 0 is further corrected through the test data. This can more accurately ensure the safe and reliable operation of the unit and avoid the occurrence of runaway accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of a traditional steam-towed compressor unit;

[0030] Figure 2 It is a schematic diagram of a conventional steam turbine generator set;

[0031] Figure 3 This is a schematic diagram of a commonly used three-in-one energy recovery unit for biological fermentation;

[0032] Figure 4 It is a schematic diagram of a turbine inlet regulating steam valve in the method of the present invention.

[0033] The meaning of the numbers in the figure are: 1-compressor, 2-turbine, 3-gearbox, 4-generator, 5-regulating steam valve. DETAILED DESCRIPTION

[0034] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] The idea of ​​the present invention is as follows: In the existing bio-fermentation energy recovery device, the power generated by the unit is the power of the steam turbine minus the power required to drive the compressor. Therefore, the amount of power that the unit can use to generate electricity depends on two aspects: one is the size of the steam turbine power, and the other is the size of the compressor power. A regulating steam valve 5 is provided on the steam inlet pipe of the steam turbine, such as Figure 4 As shown. The regulating steam valve 5 can be used to adjust the flow of steam entering the steam turbine, thereby adjusting the power of the steam turbine. In general, the regulating steam valve 5 is fully opened to ensure that all the steam allocated to the unit passes through the steam turbine 2 to do work. In addition to driving the compressor, the remaining power is all used to generate electricity. The power of the compressor 1 varies within a certain range with the changes in the intake temperature, pressure, and flow rate at different operating points. Therefore, the power generated by the generator 4 will also vary within a certain range. Within this range, the power of the generator 4 and the valve position opening of the steam turbine regulating steam valve 5 when the generator power is 0 are associated to form an approximate functional relationship. In this way, even if the high voltage suddenly loses power and the generator 4 is decoupled from the load, the steam turbine regulating steam valve 5 can quickly close a certain valve position to ensure that the steam entering the steam turbine 2 has almost no remaining power except for the power to drive the compressor 1. In this way, the unit will not overspeed, ensuring the safe and reliable operation of the unit. Generally, the power of generator 4 cannot be monitored directly. What we usually monitor on site is the generator current. Therefore, this problem can also be solved by controlling the unit operation through the functional relationship between the generator 4 current and the valve position opening of the steam valve 5 adjusted by the turbine when the generator current is 0.

[0036] The high voltage power failure control method of the energy recovery device for biological fermentation of the present invention specifically comprises the following steps:

[0037] Step 1, calculate the compressor power according to the input parameters of the compressor at different operating points (including intake pressure, intake temperature, intake flow), and obtain the compressor power at different operating points respectively; preferably, 9 operating points are taken, namely E1, E2, ..., E9, and the compressor intake pressure, intake temperature, intake flow corresponding to these 9 operating points are the 9 operating points of the compressor.

[0038] Step 2, selecting a steam turbine according to the steam turbine inlet parameters (including inlet steam pressure, temperature and flow rate) to obtain the rated power of the steam turbine;

[0039] Step 3, subtracting the compressor power at different operating points from the rated power of the steam turbine to obtain the generator power at different operating points;

[0040] Step 4: Calculate the generator current at different operating points according to the generator power at different operating points. The calculation formula is as follows:

[0041] P1=3 1 / 2 cosφ·U·I

[0042] Among them, cosφ is the power factor, U is the voltage, and I is the generator current;

[0043] Step 5, assuming that the generator power is zero, divide the turbine power at each operating point by the rated power of the turbine to obtain the valve position opening (in %) of the turbine regulating steam valve at the corresponding operating point; wherein, when the generator power is zero, the turbine power at each operating point corresponds to the compressor power at each operating point calculated in step 1.

[0044] The design of this step is based on the following considerations: The valve position opening of the regulating steam valve at the inlet of the steam turbine determines the amount of steam entering the steam turbine, thereby determining the power of the steam turbine. The opening of the regulating steam valve is linearly related to the power of the steam turbine. When the high voltage power is lost and the generator is unloaded, we hope that the generator is running at zero power at this time. Therefore, the valve position opening of the regulating steam valve of the steam turbine at this time should make the output power of the steam turbine equal to the power of driving the compressor, so that the unit does not have excess power to overspeed and avoid unit accidents.

[0045] Step 6, divide the steam turbine power by the valve position opening of the regulating steam valve to obtain the linear relationship coefficient between the steam turbine power and the regulating steam valve position opening corresponding to each operating point, average the linear relationship coefficients of all operating points to obtain the final linear relationship coefficient K, and thus obtain the relationship between the steam turbine power P3 and the regulating steam valve position opening x when the generator power is 0: P3 = Kx; at this time, the compressor power P2 = Kx, then the relationship between the generator power at the moment of high-voltage power failure and the valve position opening of the steam turbine regulating steam valve corresponding to the generator power being 0 is P1 = K(100-x);

[0046] Step 7: Combine the generator power P1=K(100-x) obtained in step 6 with P1=3 1 / 2 cosφ·U·I, and the relationship between the generator current I at the moment of high-voltage power failure and the valve position opening x of the steam turbine regulating valve corresponding to the generator current being 0 is obtained: I=T1(100-x). Let the generator current at the moment of high-voltage power failure be y, and the relationship between the generator current y and the valve position opening x of the steam turbine regulating valve corresponding to the generator current being 0 is obtained: y=T1(100-x);

[0047] Step 8, taking at least 5 compressor power values ​​(including the minimum and maximum values ​​within the range after rounding and at least 3 values ​​in the middle) within the compressor power range covered by the above 9 operating points as new compressor power values ​​at different operating points; calculating the generator power at new different operating points in the same manner as steps 3 and 4, and then obtaining the generator current; dividing the turbine power at each operating point by the rated power of the turbine to obtain the valve position opening of the turbine regulating steam valve at the corresponding operating point when the generator power is 0, and the turbine power at this time is the compressor power value obtained in step 8.

[0048] Substitute the generator current I at each operating point and the valve position opening x of the steam turbine regulating valve corresponding to the generator current being 0 into I=T2(100-x) to obtain the parameter T2 value corresponding to each operating point. Compare these five parameter T2 values ​​with the parameter T1 value in the relationship obtained in step 7. If the difference is greater than 10%, delete the parameter T2 value of the corresponding operating point. Average all parameter T2 values ​​with a difference of no more than 10% to obtain the final parameter T3 value. Replace the parameter T1 value in the relationship obtained in step 7 with the final parameter T3 value to obtain the relationship y=T1(100-x) between the corrected generator current y at the moment of high-voltage power failure and the valve position opening x of the steam turbine regulating valve corresponding to the generator current being 0.

[0049] Step 9, the unit control system monitors the circuit breaker in real time. When the high voltage power of the power grid is cut off, the circuit breaker will be detected to be open. The unit control system substitutes the generator current value at this moment into the relationship obtained in step 8, calculates the opening value of the turbine regulating steam valve, and controls the opening of the turbine regulating steam valve to adjust to the opening value obtained in this calculation.

[0050] The above technical solution can quickly adjust the opening of the steam turbine regulating valve through the actual relationship between the generator current value and the valve opening of the steam turbine regulating valve corresponding to the generator current being 0, so that the generator current value can be quickly reduced to near 0, and thus the generator power can also be quickly reduced to near 0. At this time, the steam turbine power is equal to the power value required by the compressor, avoiding the damage to the fermentation tank strain caused by the traditional interlocking shutdown method when the system high-voltage power suddenly loses power, and also eliminating the accident risk of the compressor and steam turbine overspeeding in a short period of time due to the overspeed operation of the unit. Finally, the safe operation of the unit when the high-voltage power suddenly loses power is achieved.

[0051] Example

[0052] Following the above-mentioned method of the present invention, the following embodiments are given to verify the feasibility and effectiveness of the present invention. This embodiment is a design example of high-voltage power failure control at a user site of the applicant. The site has multiple sets of steam turbine driven compressor units and multiple sets of steam turbine generator sets. At present, in order to expand production capacity, a new set of three-in-one energy recovery unit is installed to replace the combination of one set of steam turbine driven compressor unit and one set of steam turbine generator set. The specific parameters of the three-in-one energy recovery unit equipment are as follows.

[0053] 1. Design parameters of compressor

[0054] In this embodiment, the compressor model is AV50-13, E1, E2...E9 are different operating points of the compressor, and their corresponding parameters are as follows:

[0055]

[0056] 2. Design parameters of steam turbine

[0057] In this embodiment, the steam pressure at the turbine inlet is 12.9MPa(G), the temperature is 519.7℃, and the flow rate is 54.42t / h. The rated power of the steam turbine is 12500kW. Generally, the high-temperature and high-pressure steam generated by the blast furnace is distributed to the steam turbine through the main pipe, which is very stable. That is, when the turbine regulating steam valve is fully opened, the steam turbine power is 12500kW.

[0058] 3. Calculation of generator power

[0059]

[0060] 4. Calculation of the functional relationship between the generator current and the valve position of the steam turbine regulating valve corresponding to the generator current being 0. In this embodiment, at different operating points of the compressor and when the generator is running at zero power, the valve position opening of the steam turbine regulating valve is as shown in the following table.

[0061]

[0062] The power of the generator is P1, the power of the compressor is P2, then P1=12500-P2.

[0063] The opening of the steam turbine regulating valve is x. The turbine power and the opening of the regulating valve are in a linear relationship. Let the coefficient be K. The weighted average calculation from the above table yields K=124.6, which is rounded to 125.

[0064] The turbine power is P3, then P3=125x.

[0065] When the high voltage power is lost, we expect the generator power to be 0 and the turbine power to be exactly equal to the compressor power, that is, P2=125X.

[0066] At the moment of high voltage power failure, the generator power P1=125(100-x), P1=3 1 / 2 cosφ·U·I

[0067] In this embodiment, the power factor cosφ is 0.9, U is the voltage 10KV, and I is the generator current.

[0068] According to the above two formulas, 125(100-x)=3 1 / 2 cosφ·U·I, we can get

[0069] Generator current I=8.02(100-x).

[0070] Assume that the generator current at the moment of high-voltage power failure is y, and the valve position opening of the steam turbine control valve corresponding to the generator current being 0 is x. Then the functional relationship between the generator current at the moment of high-voltage power failure and the valve position opening x of the steam turbine control valve corresponding to the generator current being 0 is approximately y=8.02(100-x), that is, the parameter T1 value is 8.02.

[0071] Similarly, it can be deduced that the functional relationship between the valve position opening x of the steam turbine regulating valve corresponding to the generator current being 0 and the generator current y at the moment of high voltage power failure is approximately x=100-0.125y.

[0072] Based on the above data, combined with multiple generator disconnection tests during the on-site unit commissioning phase, the position of the steam valve of the turbine can be accurately controlled to ensure that the generator is disconnected when there is a sudden high-voltage power outage. The unit will not overspeed and can still operate safely and reliably, ensuring safe production of the entire fermentation process.

[0073] Part III:

[0074] During the on-site commissioning phase of the unit, the generator was tested. The typical operating points of the compressor are E1, E2...E9, and the power range is 5171kW to 7992kW. Therefore, the compressor test power can be tested at the minimum point, the maximum point, and then three points in the middle. The test data is as follows:

[0075]

[0076]

[0077] From the above test data, it can be concluded that the current y when the generator is disconnected and the valve position opening x of the turbine control valve when the generator current is 0 basically conform to the functional relationship of y=8.02(100-x). After correcting this functional relationship, y=8.04(100-x) is obtained, that is, the final parameter T3 value is 8.04.

[0078] It can also be obtained that the corrected functional relationship between the valve position opening x of the steam turbine regulating valve corresponding to the generator current being 0 and the generator current y at the moment of high voltage power failure is approximately x=100-0.124y.

[0079] The functional relationship between the current when the generator is disconnected and the valve position opening of the turbine regulating valve is programmed and input into the control system. By accurately controlling the valve position opening of the turbine regulating valve, it is ensured that when the high-voltage power is suddenly lost and the generator is disconnected, the unit will not overspeed and can still operate safely and reliably, ensuring the safe production of the entire fermentation process.

[0080] During the field test phase, precise control of the turbine steam valve position can ensure that when the high-voltage power is lost, the generator power is quickly reduced to zero power, ensuring the safe operation of the unit and the safe production of the subsequent bio-fermentation process.

Claims

1. A method for controlling high voltage power failure of an energy recovery device for biological fermentation, characterized in that: The specific steps include: Step 1, calculating the compressor power according to the input parameters of the compressor at different operating points, and obtaining the compressor power at different operating points respectively; Step 2, selecting a steam turbine according to the steam turbine inlet parameters to obtain the rated power of the steam turbine; Step 3, subtracting the compressor power at different operating points from the rated power of the steam turbine to obtain the generator power at different operating points; Step 4, calculating the generator current at different operating points according to the generator power at different operating points; Step 5, assuming that the generator power is zero, the turbine power at each operating point is divided by the rated power of the turbine to obtain the valve position opening of the turbine regulating steam valve at the corresponding operating point; wherein, when the generator power is zero, the turbine power at each operating point corresponds to the compressor power at each operating point calculated in step 1; Step 6, divide the steam turbine power by the valve position opening of the regulating steam valve to obtain the linear relationship coefficient between the steam turbine power and the regulating steam valve position opening corresponding to each operating point, average the linear relationship coefficients of all operating points to obtain the final linear relationship coefficient K, and thus obtain the relationship between the steam turbine power P3 and the regulating steam valve position opening x when the generator power is 0: P3 = Kx; at this time, the compressor power P2 = Kx, then the relationship between the generator power at the moment of power failure of the power grid and the steam turbine regulating steam valve position opening corresponding to the generator power being 0 is P1 = K(100-x); Step 7: Combine the generator power P1=K(100-x) obtained in step 6 with P1=3 1 / 2 cosφ·U·I, the relationship between the generator current I and the valve position opening x of the steam turbine regulating valve corresponding to the generator current being 0 is obtained as I=T1(100-x), and the generator current is y, the relationship between the generator current y and the valve position opening x of the steam turbine regulating valve corresponding to the generator current being 0 is obtained as y=T1(100-x); Step 8, taking at least 5 compressor power values ​​within the compressor power range covered by the above-mentioned multiple operating points as the compressor power values ​​of new different operating points; calculating the generator power of new different operating points in the same manner as steps 3 and 4, and then obtaining the generator current; dividing the turbine power at each operating point by the rated power of the turbine to obtain the valve position opening of the turbine regulating steam valve at the corresponding operating point when the generator power is zero, and the turbine power at this time is the compressor power value obtained in step 8; Substitute the generator current I at each operating point and the valve position opening x of the steam turbine regulating valve corresponding to the generator current being 0 into I=T2(100-x) to obtain the parameter T2 value corresponding to each operating point. Compare the five parameter T2 values ​​with the parameter T1 value in the relationship obtained in step 7. If the difference is greater than 10%, delete the parameter T2 value of the corresponding operating point. Average all parameter T2 values ​​with a difference of no more than 10% to obtain the final parameter T3 value. Replace the parameter T1 value in the relationship obtained in step 7 with the final parameter T3 value to obtain the relationship y=T3(100-x) between the corrected generator current y and the valve position opening x of the steam turbine regulating valve corresponding to the generator current being 0. Step 9, the unit control system monitors the circuit breaker in real time. When the high voltage power of the grid is cut off, the circuit breaker will be detected to be open. The unit control system substitutes the generator current value at this moment into the relationship obtained in step 8, calculates the opening value of the turbine regulating steam valve corresponding to the generator current being 0, and controls the opening of the turbine regulating steam valve to be adjusted to the opening value obtained in this calculation.

2. The high voltage power failure control method for the energy recovery device for biological fermentation according to claim 1, characterized in that: In step 1, the input parameters of the compressor include intake pressure, intake temperature, and intake flow rate.

3. The high voltage power failure control method for the energy recovery device for biological fermentation according to claim 1, characterized in that: In step 1, the number of operating points is 9.

4. The high voltage power failure control method for the energy recovery device for biological fermentation according to claim 1, characterized in that: In step 2, the turbine inlet parameters include inlet steam pressure, temperature and flow rate.

5. The high voltage power failure control method for the energy recovery device for biological fermentation according to claim 1, characterized in that: In step 4, the calculation formula of the generator current is as follows: P1=3 1 / 2 cosφ·U·I Among them, cosφ is the power factor, U is the voltage, and I is the generator current.

6. The high voltage power failure control method for the energy recovery device for biological fermentation according to claim 1, characterized in that: In step 8, the five compressor power values ​​are selected as: two values ​​after rounding of the minimum and maximum values ​​within the compressor power range of different operating points obtained in step 1 and at least three values ​​in between.

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