Oxygen generator starting method

Abstract

The present invention provides an oxygen generator startup method, comprising the following steps: starting an air compressor and an expander and pressurizing an air separation tower; entering a purification phase, opening a main refrigerant discharge valve in front of a liquid oxygen adsorber to discharge liquid enriched oxygen; opening a lower tower liquid air discharge valve to discharge liquid enriched oxygen from the air separation tower; controlling the gas discharge pressure and oxygen product release rate outside the tower, and opening a liquid nitrogen regulating valve to a certain position to return the air separation tower to a normal regulation state; adding crude argon when the oxygen purity of the device rises to a set value A; when the argon fraction exceeds a preset value B and the crude argon tower condenser pressure rises to a preset value C, regulating the crude argon tower condenser pressure to D via a flow valve; and returning the crude argon tower condenser to a normal operating state. The present invention employs a method of discharging some liquid air and liquid oxygen to lower the main refrigerant liquid level during the cold startup of the air separation unit, thereby shortening the cold startup time of the unit.

Description

Technical Field

[0001] The present invention relates to the field of energy oxygen technology, and in particular to a method for starting an oxygen concentrator. Background Art

[0002] The current state of the art uses an external compression air separation unit designed by the American company APCI. External compression equipment typically takes longer to start up than internal compression equipment. This air separation unit, when cold-started, requires 3.5 hours for nitrogen, 4 hours for oxygen, and 24 hours for liquid argon. This long startup time results in high startup energy consumption. Summary of the Invention

[0003] In response to the technical problems mentioned in the above background technology, a method for starting an oxygen concentrator is provided. The present invention mainly uses the method of actively lowering the liquid level to achieve rapid and qualified oxygen concentrator startup.

[0004] The technical means adopted in the present invention are as follows:

[0005] A method for starting an oxygen concentrator comprises the following steps:

[0006] Step 1: Start the air compressor and expander and pressurize the air separation tower;

[0007] Step 2: Enter the purification stage, open the main cooling discharge valve in front of the liquid oxygen adsorber to discharge liquid rich oxygen;

[0008] Step 3: Open the liquid air discharge valve of the lower tower to discharge the liquid oxygen-rich gas in the air separation tower;

[0009] Step 4: Control the gas discharge pressure outside the tower and the amount of oxygen product released, and open the liquid nitrogen regulating valve to a certain position to turn the air separation tower into a normal regulation state;

[0010] Step 5: When the oxygen purity of the device rises to the set value A, crude argon is added;

[0011] Step 6: When the amount of argon fraction exceeds a preset value B and the pressure of the crude argon column condenser rises to a preset value C, the pressure of the crude argon column condenser is adjusted to D through a flow valve;

[0012] Step 7: The crude argon column condenser enters a normal working state.

[0013] Furthermore, in step 2, after entering the purification stage, the main cold discharge valve in front of the liquid oxygen adsorber is opened so that the opening of the operating valve is reduced to 30-35%, so that the liquid level of the main condenser evaporator is reduced to 90-95%.

[0014] Furthermore, in step 3, the lower tower liquid air discharge valve is opened so that the opening of the valve is operated to 45-50%, so that the liquid level of the lower tower liquid air is reduced to 45-50%.

[0015] Furthermore, in step 4, the certain position is a nitrogen regulating valve whose valve opening is opened to 41-43%.

[0016] Furthermore, the set value A in step 5 is 95.6-96%.

[0017] Furthermore, the preset value B in step 5 is 30000m 3 / h.

[0018] Furthermore, the preset value C is 58-60 kPa.

[0019] Furthermore, the preset value D does not exceed 70KPa at most and cannot be lower than 50KPa at least.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] The present invention adopts the operation method of discharging part of the liquid air and liquid oxygen to reduce the main cooling liquid level during the cold start of the air separation unit, which can shorten the cold start time of the unit. Figure 2 As shown, oxygen and nitrogen can be delivered one hour in advance, and argon can be delivered 12 hours in advance. This allows the air compressor to work effectively in advance, saving energy and increasing product production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0023] Figure 1 Schematic diagram of the overall device of the present invention.

[0024] Figure 2 Schematic diagram of the effects before and after the implementation of the present invention. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0026] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0027] like Figure 1 As shown, the present invention provides an oxygen concentrator startup method, comprising the following steps:

[0028] Step 1: Start the air compressor and expander and pressurize the air separation tower;

[0029] Step 2: During the purification phase, open the main coolant discharge valve in front of the liquid oxygen adsorber to discharge the liquid enriched oxygen. After entering the purification phase, open the main coolant discharge valve in front of the liquid oxygen adsorber to 30-35% of the operating valve opening, allowing the liquid level in the main condenser evaporator to drop to 90-95%. This equipment is a critical component of large-scale oxygen generators, connecting the upper and lower towers. Its proper operation and optimal operating conditions are crucial to ensuring that the oxygen and nitrogen products meet standards and are delivered to users.

[0030] Step 3: Open the lower column liquid air discharge valve to discharge the liquid oxygen-rich in the air separation tower; open the lower column liquid air discharge valve to operate the valve opening to 45-50%, so that the liquid level of the lower column liquid air drops to 45-50%.

[0031] Step 4: Control the gas discharge pressure outside the tower and the oxygen product release rate, and open the liquid nitrogen regulating valve to a certain position so that the air separation tower returns to a normal regulation state; the certain position is when the valve opening of the nitrogen regulating valve is opened to 41-43%.

[0032] Step 5: When the oxygen purity of the device rises to the set value A, crude argon is added; the set value A is 95.6-96%. What is measured here is the oxygen purity during the startup of the device when the oxygen purity changes from poor to good. Specifically, the main cooling work requires the condensation of nitrogen gas from the lower tower and the evaporation of liquid oxygen from the upper tower (achieved by utilizing the temperature difference between the two substances for heat exchange in the main condenser evaporator), that is, the purity after the liquid oxygen evaporates into gaseous oxygen. (Since the product purity has not yet reached the standard, the evaporated gaseous oxygen is sent outside the tower and discharged). Add crude argon tower, which is marked by the pressure and resistance of the crude argon tower reaching or approaching normal values ​​(58~60KPa) and the liquid air evaporation volume gradually reaching 30,000m 3 / h, indicating that the crude argon tower has established distillation and reached normal working state. Therefore, the amount is an important indicator value to judge whether the crude argon tower has started to work.

[0033] Step 6: When the amount of argon fraction exceeds the preset value B and the pressure of the crude argon column condenser rises to the preset value C, the pressure of the crude argon column condenser is adjusted to D through the flow valve; the preset value B is 30000m 3 / h. The preset value C is 58-60kPa. The preset value D does not exceed 70kPa at most and cannot be lower than 50kPa at least.

[0034] Step 7: The crude argon column condenser enters a normal working state.

[0035] After the startup method of the present invention, the time it takes for oxygen, nitrogen and argon products to meet the standards and be delivered to users (the shortened time is 2.5 hours for nitrogen, 3.5 hours for oxygen, and 12 hours for argon) is compared with the time given by the equipment manufacturer and technical operating procedures before the method is adopted and the time required in actual operation (3.5 hours for nitrogen, 4 hours for oxygen, and 24 hours for argon). The above time data all refer to the time from the startup of the device to the time when the product purity meets the standards and is delivered to the user's pipeline network. The time comparison is clear at a glance.

[0036] Example 1

[0037] As an embodiment of the present application, after the main air separation device is normally started, this method enters the product purity adjustment stage and begins to actively lower the liquid level of the main condenser evaporator and the air separation lower tower, artificially changing the reflux ratio in the air separation tower, and increasing the evaporation of the volatile component nitrogen, which is beneficial to the separation of oxygen and nitrogen and shortens the time for each product to meet the purity requirements.

[0038] Step 1: Start the air compressor, expander, and air separation tower pressurization and gas guide according to the normal startup operation procedure. The pressure PI9 of the upper tower of the air separation increases to 58-65KPa, and the pressure PI11 of the lower tower of the air separation increases to 450-480KPa.

[0039] Step 2: Open the throttle valve for the liquid air from the lower air separation column to the upper air separation column to a normal opening of 60-65%. After entering the purification phase, open the main cold discharge valve V322 before the liquid oxygen adsorber to 30-35% to discharge the liquid enriched oxygen. When the liquid level LT3 in the main condenser evaporator drops from over 100% at cold shutdown to 90-95%, close the discharge valve V322.

[0040] Step 3: Open the lower column liquid air discharge valve V270 to 45-50% to discharge the oxygen-rich liquid air in the lower air separation column. When the lower column liquid level LT3 drops to 45-50%, close the discharge valve V270.

[0041] Step 4: Set the given value of the gas discharge regulator PIC79 outside the tower to 9.5KPa, adjust the opening of the oxygen release valve FV64, and release the oxygen product to 25000-27000m3 / h. Open the liquid nitrogen regulating valve HV20 to 41-43%, and the main air separation tower operating condition will quickly return to normal.

[0042] Step 5: When the oxygen purity AI114 rises to 95.6-96% and is fed into the crude argon tower, the crude argon tower liquid level regulating valve automatically controls the given value to 70%, the crude argon tower condenser liquid air reflux valve HV78 is manually opened to 10-12%, and the crude argon tower liquid air reflux valve HV58 is manually opened to 100%.

[0043] Step 6: Wait until the argon distillate reaches 30,000 m3 3 / h or more, and the crude argon tower condenser pressure rises to 50-55kPa, use FV-55 to adjust the crude argon tower condenser pressure to 58-60kPa.

[0044] Step 7: The crude argon tower operating conditions quickly return to normal.

[0045] The serial numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. In the above embodiments of the present invention, the description of each embodiment has its own focus. For parts not described in detail in a particular embodiment, please refer to the relevant description of other embodiments. In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented by other means.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for starting an oxygen concentrator, characterized in that: The following steps are involved: Step 1: Start the air compressor and expander and pressurize the air separation tower; Step 2: Entering the purification stage, opening the main cooling discharge valve in front of the liquid oxygen adsorber to discharge liquid enriched oxygen; in said step 2, after entering the purification stage, opening the main cooling discharge valve in front of the liquid oxygen adsorber to operate the valve opening to 30-35%, so that the liquid level of the main condenser evaporator is reduced to 90-95%; Step 3: Open the lower column liquid air discharge valve to discharge the liquid-enriched oxygen in the air separation tower; in step 3, the lower column liquid air discharge valve is opened to operate the valve opening to 45-50%, so that the liquid level of the lower column liquid air drops to 45-50%; Step 4: Control the gas discharge pressure outside the tower and the amount of oxygen product released, and open the liquid nitrogen regulating valve to a certain position to turn the air separation tower into a normal regulation state; Step 5: When the oxygen purity of the device rises to the set value A, crude argon is added; Step 6: When the amount of argon fraction exceeds a preset value B and the pressure of the crude argon column condenser rises to a preset value C, the pressure of the crude argon column condenser is adjusted to a preset value D through a flow valve; Step 7: The crude argon column condenser enters a normal working state.

2. The oxygen concentrator startup method according to claim 1, characterized in that: In step 4, the certain position is that the opening of the nitrogen regulating valve is opened to 41-43%.

3. The oxygen concentrator startup method according to claim 1, characterized in that: The set value A in step 5 is 95.6-96%.

4. The oxygen concentrator startup method according to claim 1, characterized in that: The preset value B in step 5 is .

5. The oxygen concentrator startup method according to claim 1, characterized in that: The preset value C is 58-60 kPa.

6. The oxygen concentrator startup method according to claim 1, characterized in that: The preset value D is not more than 70kPa at most and not less than 50kPa at least.

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