Electrochemical synthesis ammonia unit yield power consumption measuring and calculating method, system and electronic equipment

Abstract

The invention provides a method for measuring and calculating the unit yield power consumption of electrochemical synthesis ammonia, the method is used for measuring and calculating the unit yield power consumption of an electrochemical synthesis ammonia device, and the electrochemical synthesis ammonia device at least comprises a plasma generator, a circulating electrolyte pump, an air pump and an electro-catalysis power supply; the method comprises the following steps: S100, obtaining effective power consumption of the electrochemical ammonia synthesis device within operation time tr; s200, the mass of ammonia generated by the electrochemical ammonia synthesis device within the operation time tr is obtained; s300, based on the effective power consumption and the mass of ammonia, the electrochemical synthesis ammonia unit yield power consumption is calculated, and the effective power consumption of the electrochemical synthesis ammonia device comprises the power consumption of a plasma generator, the power consumption of a circulating electrolyte pump, the power consumption of an air pump and the power consumption of an electro-catalysis power source.

Description

Technical Field

[0001] This disclosure belongs to the field of electrochemical ammonia synthesis technology, specifically relating to a method, system, electronic device, and computer-readable storage medium for calculating the power consumption per unit yield of electrochemical ammonia synthesis. Background Technology

[0002] pNOR-eNO x Electrochemical ammonia synthesis technology has the advantages of mild reaction conditions, low reaction pressure, and high theoretical energy efficiency. This technology comprises two main steps: first, nitrogen and oxygen in the raw material air are combined using plasma to generate various nitrogen oxides (pNOR); then, an alkaline solution is used to absorb the nitrogen oxides generated in the previous step, converting them into NO. x- Ions (nitrate, nitrite, etc.) are reduced to NH3 (eNO3) through electrocatalytic reduction. x ).

[0003] However, assessing the actual energy consumption of this technology faces challenges. The overall energy consumption of an electrochemical ammonia synthesis unit comprises multiple components, including a plasma generator, circulating pump, gas pump, and electrocatalytic power supply. In particular, not all the electrical energy input to the plasma generator is effectively used to generate active species; some energy is lost as heat, reflected waves, etc. Calculating the apparent energy consumption per unit ammonia yield based solely on the unit's total input power and operating time will significantly deviate from the actual effective energy consumption used in the ammonia synthesis reaction due to differences in equipment efficiency, failing to accurately reflect the energy efficiency level of this technology. This complicates catalyst performance evaluation, process condition optimization, and cross-sectional comparisons of different technologies.

[0004] Therefore, there is an urgent need for a method that can accurately isolate equipment losses and truly reflect pNOR-eNO. x Methods for calculating the effective energy consumption of the electrochemical ammonia synthesis process. Summary of the Invention

[0005] The embodiments disclosed herein aim to at least solve one of the technical problems existing in the prior art, and provide a method for calculating the power consumption per unit yield of electrochemical ammonia synthesis.

[0006] The first aspect of this disclosure provides a method for calculating the power consumption per unit yield of electrochemical ammonia synthesis. The method is used to calculate the power consumption per unit yield of an electrochemical ammonia synthesis device, which includes at least a plasma generator, a circulating electrolyte pump, a gas pump, and an electrocatalytic power supply. The method includes the following steps: S100: Obtain the operating time t of the electrochemical ammonia synthesis device. r Effective power consumption within ; S200: Obtain the operating time t of the electrochemical ammonia synthesis unit. r The mass of ammonia produced internally ; S300: Based on effective power consumption and the mass of ammonia Calculate the power consumption per unit yield of electrochemical ammonia synthesis The calculation formula is: ; The effective power consumption of the electrochemical ammonia synthesis unit is as follows. This includes the power consumption of the plasma generator, the circulating electrolyte pump, the gas pump, and the electrocatalytic power supply.

[0007] In some embodiments of this disclosure, step S100 includes: Obtain the input power of the plasma generator And calculate the effective power of the plasma generator actually put into the reaction process. The calculation formula is: ; in, The microwave reflection coefficient is... The conversion factor between electricity and microwave; Obtain the power of the circulating electrolyte pump air pump power The power of the electrocatalytic power supply Calculate effective power consumption The calculation formula is: .

[0008] In some embodiments of this disclosure, step S200 includes: S210: After the electrochemical ammonia synthesis device stops operating, the ammonia dissolved in the electrolyte and the gaseous ammonia remaining in the sealed space of the reactor are collected; S220: The collected ammonia is converted into ammonium chloride crystals and weighed to obtain the mass of ammonium chloride. ; S230: Based on the molecular weight ratio of ammonia to ammonium chloride, the mass of ammonium chloride... Calculate the mass of the ammonia .

[0009] In some embodiments of this disclosure, step S210 includes: A purging gas is introduced into the electrolyte of the electrochemical ammonia synthesis device; The gas discharged from the electrochemical ammonia synthesis device is passed into a dilute hydrochloric acid solution; Based on continuous measurements showing that the pH value of the dilute hydrochloric acid solution remained essentially unchanged, it was determined that the generated ammonia had been fully collected.

[0010] In some embodiments of this disclosure, the mass of ammonia in step S230 The calculation formula is: ; in, This represents the molecular weight of ammonia. This represents the molecular weight of ammonium chloride.

[0011] The second aspect of this disclosure provides a power consumption calculation system for unit yield of electrochemical ammonia synthesis. This system is used to calculate the power consumption per unit yield of an electrochemical ammonia synthesis device, which includes at least a plasma generator, a circulating electrolyte pump, a gas pump, and an electrocatalytic power supply. The power consumption calculation system for unit yield of electrochemical ammonia synthesis includes: The first acquisition module is used to acquire data about the electrochemical ammonia synthesis unit during operating time t. r Effective power consumption within ; The second acquisition module is used to acquire the operating time t of the electrochemical ammonia synthesis unit. r The mass of ammonia produced internally ; The calculation module is used to calculate based on effective power consumption. and the mass of ammonia Calculate the power consumption per unit yield of electrochemical ammonia synthesis The calculation formula is: ; The effective power consumption of the electrochemical ammonia synthesis unit is as follows. This includes the power consumption of the plasma generator, the circulating electrolyte pump, the gas pump, and the electrocatalytic power supply.

[0012] In some embodiments of this disclosure, the first acquisition module includes a first acquisition unit, a first calculation unit, a second acquisition unit, and a second calculation unit; The first acquisition unit is used to acquire the input power of the plasma generator. The first calculation unit calculates the effective power of the plasma generator in the actual reaction process according to the following formula. : ; in, The microwave reflection coefficient is... The conversion factor between electricity and microwave; The second acquisition unit is used to acquire the power of the circulating electrolyte pump. air pump power The power of the electrocatalytic power supply The second calculation unit calculates the effective power consumption according to the following formula. : .

[0013] In some embodiments of this disclosure, the second acquisition module includes a third acquisition unit and a third calculation unit; The third acquisition unit is used to collect ammonia dissolved in the electrolyte and gaseous ammonia remaining in the sealed space of the reactor after the electrochemical ammonia synthesis device has stopped operating; it is also used to convert the collected ammonia into ammonium chloride crystals and weigh them to obtain the mass of ammonium chloride. ; The third calculation unit is used to calculate the mass of ammonium chloride based on the ratio of the molecular weights of ammonia and ammonium chloride. The mass of the ammonia is calculated using the following formula. : .

[0014] A third aspect of this disclosure provides an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory storing computer-executable instructions; and the processor executing the computer-executable instructions stored in the memory to implement the method as described in any of the above embodiments.

[0015] This disclosure provides a fourth aspect of a computer-readable storage medium storing computer-executable instructions that, when executed by a processor, are used to implement the method as described in any of the above embodiments.

[0016] According to the method for calculating the power consumption per unit yield of electrochemical ammonia synthesis according to the embodiments of this disclosure, the power consumption of the electrochemical ammonia synthesis unit during operation time t is first obtained. r The effective power consumption and the mass of ammonia produced during that time period are used to calculate the unit output power consumption of the electrochemical ammonia synthesis unit. The effective power consumption is the power consumption after reducing losses such as reflected waves from the plasma generator. The power consumption of the unit output of the electrochemical ammonia synthesis unit can be calculated by using the effective power consumption and the mass of ammonia, thereby obtaining the stripping equipment loss and truly reflecting the effective energy consumption of the pNOR-eNOx electrochemical ammonia synthesis process. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the power consumption calculation method for unit yield of electrochemical ammonia synthesis in this embodiment of the invention. Figure 2 This is a schematic diagram of the electrochemical ammonia synthesis device in an embodiment of the present invention.

[0018] The labels in the attached diagram are as follows: 1. Plasma generator; 2. Circulating electrolyte pump; 3. Gas pump; 4. Electrocatalytic power supply; 5. Nitrogen oxide absorption tower; 6. Electrocatalytic reduction electrolytic cell; 7. Product collection unit; 8. KOH buffer tank; 9. Electrochemical workstation. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining this disclosure and are not intended to limit the disclosure. The described embodiments are some, but not all, of the embodiments of this disclosure. Based on the described embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this disclosure.

[0020] The method for calculating the power consumption per unit yield of electrochemical ammonia synthesis provided in this invention can be executed by an electronic device or a functional module or entity within an electronic device capable of implementing the calculation method. For example, it could be a calculation unit or host computer software integrated into the control system of an electrochemical ammonia synthesis device. The calculation method provided in this application embodiment will be described below using an electronic device as an example.

[0021] like Figure 2 As shown, the pNOR-eNOx electrochemical ammonia synthesis device can be considered as a system, which may include a plasma generator 1, a circulating electrolyte pump 2, a gas pump 3, an electrocatalytic power supply 4, a nitrogen oxide absorption tower 5, an electrocatalytic reduction electrolytic cell 6, a product collection unit 7, a KOH buffer tank 8, and an electrochemical workstation 9, etc.

[0022] The plasma generator 1 converts incoming air into nitrogen oxides (NOx). An air pump 3 supplies air to the plasma generator 1. The NOx absorption tower 5 contains an alkaline electrolyte to absorb NOx gas generated by the plasma, forming NOx- ions (such as nitrate and nitrite). A circulating electrolyte pump 2 circulates the electrolyte between the absorption tower 5 and the electrolytic cell 6. A KOH buffer tank is located between the absorption tower 5 and the electrolytic cell 6 to store a portion of the KOH solution. The electrocatalytic reduction electrolytic cell 6 contains a cathode and an anode. An electrochemical workstation 9 is connected to the electrocatalytic reduction electrolytic cell 6, and an electrocatalytic power supply 4 powers it, reducing NOx- ions in the electrolyte to ammonia (NH3). A product collection unit 7 collects and measures the generated ammonia.

[0023] The total energy consumption during the operation of the electrochemical ammonia synthesis unit mainly comes from the power consumption of plasma generator 1, circulating electrolyte pump 2, gas pump 3, and electrocatalytic power supply 4. However, not all the input electrical energy of plasma generator 1 is effectively used to generate plasma, due to power conversion efficiency (electro-microwave conversion coefficient). ) and microwave energy reflection (microwave reflection coefficient) Therefore, when evaluating the energy efficiency of this technology, it is necessary to distinguish between apparent energy consumption and actual effective energy consumption. Only by using actual effective energy consumption can the true value of pNOR-eNO be reflected. x The effective energy consumption corresponding to the electrochemical synthesis of ammonia.

[0024] The electrochemical ammonia synthesis unit operates for time t. r The apparent energy consumption within is: ; in, For the input power of the plasma generator, For the power of the circulating electrolyte pump, For the power of the air pump, This represents the power of the electrocatalytic power source.

[0025] The apparent power consumption per unit yield of ammonia synthesized by the electrochemical ammonia synthesis unit is: ; in, For the electrochemical ammonia synthesis unit during operation time t r The mass of ammonia produced internally.

[0026] like Figure 1 As shown, embodiments of this disclosure provide a method for calculating the power consumption per unit yield of electrochemical ammonia synthesis. The method is used to calculate the power consumption per unit yield of an electrochemical ammonia synthesis device, which includes at least a plasma generator, a circulating electrolyte pump, a gas pump, and an electrocatalytic power supply. The method includes the following steps: S100: Obtain the operating time t of the electrochemical ammonia synthesis device. r Effective power consumption within ; S200: Obtain the operating time t of the electrochemical ammonia synthesis unit. r The mass of ammonia produced internally ; S300: Based on effective power consumption and the mass of ammonia Calculate the power consumption per unit yield of electrochemical ammonia synthesis The calculation formula is: ; The effective power consumption of the electrochemical ammonia synthesis unit is as follows. This includes the power consumption of the plasma generator, the circulating electrolyte pump, the gas pump, and the electrocatalytic power supply.

[0027] According to the method for calculating the power consumption per unit yield of electrochemical ammonia synthesis according to the embodiments of this disclosure, the power consumption of the electrochemical ammonia synthesis unit during operation time t is first obtained. r The effective power consumption and the mass of ammonia produced during that time period are used to calculate the unit output power consumption of the electrochemical ammonia synthesis unit. The effective power consumption is the power consumption after reducing losses such as reflected waves from the plasma generator. The power consumption of the unit output of the electrochemical ammonia synthesis unit can be calculated by using the effective power consumption and the mass of ammonia, thereby obtaining the stripping equipment loss and truly reflecting the effective energy consumption of the pNOR-eNOx electrochemical ammonia synthesis process.

[0028] In some embodiments of this disclosure, step S100 includes: S110: Obtain the input power of the plasma generator And calculate the effective power of the plasma generator actually put into the reaction process. The calculation formula is: (2); in, The microwave reflection coefficient is... The conversion factor between electricity and microwave; S120: Obtain the power of the circulating electrolyte pump air pump power The power of the electrocatalytic power supply Calculate effective power consumption The calculation formula is: (3).

[0029] The effective power in S110 Substitute the effective power consumption into the calculation formula (2). In the process, the effective power consumption is obtained. The calculation formula is as follows: (4); Substituting formula (4) into formula (1) yields the power consumption per unit yield of electrochemical ammonia synthesis. The expression: (5).

[0030] It should be noted that the power of the circulating electrolyte pump... air pump power The power of the electrocatalytic power supply These are the corresponding rated power and input power of the plasma generator. The power can be measured by a power meter or read from the parameters on the device nameplate.

[0031] In some embodiments of this disclosure, step S200 includes: S210: After the electrochemical ammonia synthesis device stops operating, the ammonia dissolved in the electrolyte and the gaseous ammonia remaining in the sealed space of the reactor are collected; S220: The collected ammonia is converted into ammonium chloride crystals and weighed to obtain the mass of ammonium chloride. ; S230: Based on the molecular weight ratio of ammonia to ammonium chloride, the mass of ammonium chloride... Calculate the mass of the ammonia .

[0032] In some embodiments of this disclosure, step S210 includes: A purging gas is introduced into the electrolyte of the electrochemical ammonia synthesis device; The gas discharged from the electrochemical ammonia synthesis device is passed into a dilute hydrochloric acid solution; Based on continuous measurements showing that the pH value of the dilute hydrochloric acid solution remained essentially unchanged, it was determined that the generated ammonia had been fully collected.

[0033] In some embodiments of this disclosure, the mass of ammonia in step S230 The calculation formula is: (6); in, This represents the molecular weight of ammonia. This represents the molecular weight of ammonium chloride.

[0034] Substituting formulas (4) and (5) into formula (1) respectively yields the power consumption per unit yield of electrochemical ammonia synthesis. : (7).

[0035] The power consumption per unit yield of electrochemical ammonia synthesis can be calculated using formula (7). .

[0036] A second aspect of this disclosure provides a power consumption calculation system for unit yield of electrochemical ammonia synthesis. This system is used to calculate the power consumption per unit yield of an electrochemical ammonia synthesis apparatus. The electrochemical ammonia synthesis apparatus includes at least a plasma generator, a circulating electrolyte pump, a gas pump, and an electrocatalytic power supply. The power consumption calculation system for unit yield of electrochemical ammonia synthesis includes: The first acquisition module is used to acquire data about the electrochemical ammonia synthesis unit during operating time t. r Effective power consumption within ; The second acquisition module is used to acquire the operating time t of the electrochemical ammonia synthesis unit. r The mass of ammonia produced internally ; The calculation module is used to effectively manage power consumption. and the mass of ammonia Calculate the power consumption per unit yield of electrochemical ammonia synthesis The calculation formula is: ; The effective power consumption of the electrochemical ammonia synthesis unit is as follows. This includes the power consumption of the plasma generator, the circulating electrolyte pump, the gas pump, and the electrocatalytic power supply.

[0037] The electrochemical ammonia synthesis unit yield power consumption calculation system disclosed herein first obtains the power consumption of the electrochemical ammonia synthesis unit during the operating time t of the electrochemical ammonia synthesis device via a first acquisition module. r The effective power consumption within the time frame is obtained through the second acquisition module, which determines the running time t. r The mass of ammonia produced internally is used to calculate the unit output power consumption of the electrochemical ammonia synthesis unit based on the effective power consumption and the mass of ammonia. This yields the stripping equipment loss and accurately reflects the effective energy consumption of the pNOR-eNOx electrochemical ammonia synthesis process.

[0038] In some embodiments of this disclosure, the first acquisition module includes a first acquisition unit, a first calculation unit, a second acquisition unit, and a second calculation unit; The first acquisition unit is used to acquire the input power of the plasma generator. The first calculation unit calculates the effective power of the plasma generator in the actual reaction process according to the following formula. : ; in, The microwave reflection coefficient is... The conversion factor between electricity and microwave; The second acquisition unit is used to acquire the power of the circulating electrolyte pump. air pump power The power of the electrocatalytic power supply The second calculation unit calculates the effective power consumption according to the following formula. : .

[0039] In some embodiments of this disclosure, the second acquisition module includes a third acquisition unit and a third calculation unit; The third acquisition unit is used to collect ammonia dissolved in the electrolyte and gaseous ammonia remaining in the sealed space of the reactor after the electrochemical ammonia synthesis device has stopped operating; it is also used to convert the collected ammonia into ammonium chloride crystals and weigh them to obtain the mass of ammonium chloride. ; The third calculation unit is used to calculate the mass of ammonium chloride based on the ratio of the molecular weights of ammonia and ammonium chloride. The mass of the ammonia is calculated using the following formula. : .

[0040] The measurement system in this disclosure can be an electronic device or a component within an electronic device, such as an integrated circuit or a chip. The electronic device can be a personal computer, a server, an industrial control computer, or an embedded system, etc.

[0041] A third aspect of this disclosure provides an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory storing computer-executable instructions; and the processor executing the computer-executable instructions stored in the memory to implement the method as described in any of the above embodiments.

[0042] It should be noted that the electronic devices in this disclosure include the mobile electronic devices and non-mobile electronic devices described above.

[0043] This disclosure provides a fourth aspect of a computer-readable storage medium storing computer-executable instructions that, when executed by a processor, are used to implement the method as described in any of the above embodiments.

[0044] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A method for calculating the power consumption per unit yield of electrochemical ammonia synthesis, characterized in that, The method is used to calculate the power consumption per unit output of an electrochemical ammonia synthesis device, wherein the electrochemical ammonia synthesis device includes at least a plasma generator, a circulating electrolyte pump, a gas pump, and an electrocatalytic power supply; the method includes the following steps: S100: Obtain the operating time t of the electrochemical ammonia synthesis device. r Effective power consumption within ; S200: Obtain the operating time t of the electrochemical ammonia synthesis unit. r The mass of ammonia produced internally ; S300: Based on effective power consumption and the mass of ammonia Calculate the power consumption per unit yield of electrochemical ammonia synthesis The calculation formula is: ； The effective power consumption of the electrochemical ammonia synthesis unit is as follows. This includes the power consumption of the plasma generator, the circulating electrolyte pump, the gas pump, and the electrocatalytic power supply.

2. The method for calculating the power consumption per unit yield of electrochemical ammonia synthesis according to claim 1, characterized in that, Step S100 includes: Obtain the input power of the plasma generator And calculate the effective power of the plasma generator actually put into the reaction process. The calculation formula is: ； in, The microwave reflection coefficient is... The conversion factor between electricity and microwave; Obtain the power of the circulating electrolyte pump air pump power The power of the electrocatalytic power supply Calculate effective power consumption The calculation formula is: 。 3. The method for calculating the power consumption per unit yield of electrochemical ammonia synthesis according to claim 1, characterized in that, Step S200 includes: S210: After the electrochemical ammonia synthesis device stops operating, the ammonia dissolved in the electrolyte and the gaseous ammonia remaining in the sealed space of the reactor are collected; S220: The collected ammonia is converted into ammonium chloride crystals and weighed to obtain the mass of ammonium chloride. ; S230: Based on the molecular weight ratio of ammonia to ammonium chloride, the mass of ammonium chloride... Calculate the mass of the ammonia .

4. The method for calculating the power consumption per unit yield of electrochemical ammonia synthesis according to claim 3, characterized in that, Step S210 includes: A purging gas is introduced into the electrolyte of the electrochemical ammonia synthesis device; The gas discharged from the electrochemical ammonia synthesis device is passed into a dilute hydrochloric acid solution; Based on continuous measurements showing that the pH value of the dilute hydrochloric acid solution remained essentially unchanged, it was determined that the generated ammonia had been fully collected.

5. The method for calculating the power consumption per unit yield of electrochemical ammonia synthesis according to claim 3, characterized in that, The mass of ammonia in step S230 The calculation formula is: ； in, This represents the molecular weight of ammonia. This represents the molecular weight of ammonium chloride.

6. A system for calculating the power consumption per unit yield of electrochemical ammonia synthesis, characterized in that, The electrochemical ammonia synthesis unit output power consumption calculation system is used to calculate the unit output power consumption of the electrochemical ammonia synthesis device, which includes at least a plasma generator, a circulating electrolyte pump, a gas pump, and an electrocatalytic power supply. The power consumption calculation system for unit yield of electrochemical ammonia synthesis includes: The first acquisition module is used to acquire data about the electrochemical ammonia synthesis unit during operating time t. r Effective power consumption within ; The second acquisition module is used to acquire the operating time t of the electrochemical ammonia synthesis unit. r The mass of ammonia produced internally ; The calculation module is used to calculate based on effective power consumption. and the mass of ammonia Calculate the power consumption per unit yield of electrochemical ammonia synthesis The calculation formula is: ； The effective power consumption of the electrochemical ammonia synthesis unit is as follows. This includes the power consumption of the plasma generator, the circulating electrolyte pump, the gas pump, and the electrocatalytic power supply.

7. The electrochemical ammonia synthesis unit yield power consumption calculation system according to claim 6, characterized in that, The first acquisition module includes a first acquisition unit, a first calculation unit, a second acquisition unit, and a second calculation unit; The first acquisition unit is used to acquire the input power of the plasma generator. The first calculation unit calculates the effective power of the plasma generator in the actual reaction process according to the following formula. : ； in, The microwave reflection coefficient is... The conversion factor between electricity and microwave; The second acquisition unit is used to acquire the power of the circulating electrolyte pump. air pump power The power of the electrocatalytic power supply The second calculation unit calculates the effective power consumption according to the following formula. : 。 8. The electrochemical ammonia synthesis unit yield power consumption calculation system according to claim 6, characterized in that, The second acquisition module includes a third acquisition unit and a third calculation unit; The third acquisition unit is used to collect the ammonia dissolved in the electrolyte and the gaseous ammonia remaining in the sealed space of the reactor after the electrochemical ammonia synthesis device stops operating; This is used to convert collected ammonia into ammonium chloride crystals and weigh them to obtain the mass of ammonium chloride. ; The third calculation unit is used to calculate the mass of ammonium chloride based on the ratio of the molecular weights of ammonia and ammonium chloride. The mass of the ammonia is calculated using the following formula. : 。 9. An electronic device, characterized in that, include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method as described in any one of claims 1 to 6.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1 to 6.

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