Molecular sieve energy-saving system

Abstract

The utility model provides a molecular sieve energy-saving system which comprises a heat exchanger, a nitrogen pipe and an air pipe, the heat exchanger comprises a first air inlet, a first air outlet, a second air inlet and a second air outlet which are respectively connected with a first air inlet pipe, a first air outlet pipe, a second air inlet pipe and a second air outlet pipe; the nitrogen pipe is sequentially connected with a first nitrogen control valve, a second nitrogen control valve and a heater in the air inlet direction, and the air pipe is sequentially connected with an air compressor and an air control valve in the air inlet direction. When the device is used, waste nitrogen generated in the air separation system is introduced into the nitrogen pipe, air is introduced into the air pipe, the air reaches about 120 DEG C after being compressed by the air compressor, then the compressed air and the waste nitrogen exchange heat in the heat exchanger, and the waste nitrogen is heated to about 70 DEG C and enters the heater to be continuously heated, so that the energy consumption is saved, and the cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of molecular sieves, in particular to a molecular sieve energy-saving system. Background Art

[0002] The air separation system utilizes a process combining ambient-temperature molecular sieve adsorption purification with a booster turbine expander and structured packing tower gas production. The molecular sieve purification system is a key component of the air separation plant, primarily adsorbing most impurities such as water, carbon dioxide, and hydrocarbons from the air. Whether the treated air meets standards directly impacts the operating performance of the entire air separation plant. Once the molecular sieve purification unit is saturated with adsorption, it undergoes regeneration for reuse. Currently, most molecular sieves in air separation systems are regenerated using heating with contaminated nitrogen, which consumes approximately 11% of the plant's total energy consumption, resulting in high energy consumption and costs. Utility Model Content

[0003] In view of the above problems, the present invention proposes a molecular sieve energy-saving system, which has the characteristics of low energy consumption and low cost.

[0004] The technical solution of the present utility model is achieved as follows:

[0005] A molecular sieve energy-saving system comprises a heat exchanger, a nitrogen pipe and an air pipe; the heat exchanger comprises a first air inlet, a first air outlet, a second air inlet and a second air outlet, the first air inlet is connected to the first air inlet pipe, the first air outlet is connected to the first air outlet pipe, the second air inlet is connected to the second air inlet pipe, the second air outlet is connected to the second air outlet pipe, the first air inlet pipe is connected to the first control valve I, the first air outlet pipe is connected to the first control valve II, the second air inlet pipe is connected to the second control valve I, and the second air outlet pipe is connected to the second control valve II; the nitrogen pipe is sequentially connected to the first nitrogen control valve, the second nitrogen control valve and the heater in the air inlet direction, the other ends of the first air inlet pipe and the first air outlet pipe are respectively connected to the nitrogen pipe, and the second nitrogen control valve is located between the first air inlet pipe and the first air outlet pipe; the air pipe is sequentially connected to the air compressor and the air control valve in the air inlet direction, the other ends of the second air inlet pipe and the second air outlet pipe are respectively connected to the air pipe, and the air control valve is located between the second air inlet pipe and the second air outlet pipe.

[0006] Preferably, the air outlet end of the air pipe is also connected to a cooler.

[0007] Preferably, the cooler is a water-cooled cooler.

[0008] Preferably, the heat exchanger is a shell and tube heat exchanger.

[0009] Preferably, the heater is an electric heater.

[0010] The beneficial effects of the utility model are as follows: when in use, the nitrogen pipe is fed with the dirty nitrogen generated in the air separation system, and the air pipe is fed with air. The air is compressed by the air compressor to a temperature of about 120°C, and then the compressed air and the dirty nitrogen are exchanged with heat in the heat exchanger. The dirty nitrogen is heated to about 70°C and enters the heater for further heating, thereby saving energy and reducing costs. The compressed air temperature drops to about 80°C and then enters the cooler for cooling, which also reduces the workload of the cooler and saves circulating cooling water. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] 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 only 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 work.

[0012] Figure 1 It is a structural diagram of the present utility model.

[0013] Reference numerals in the figure: 1-heat exchanger, 2-nitrogen pipe, 3-air pipe, 11-first air inlet pipe, 12-first air outlet pipe, 13-second air inlet pipe, 14-second air outlet pipe, 15-first control valve I, 16-first control valve II, 17-second control valve I, 18-second control valve II, 21-first nitrogen control valve, 22-second nitrogen control valve, 23-heater, 31-air compressor, 32-air control valve, 33-cooler. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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 are within the scope of protection of the present invention.

[0015] Reference Figure 1A molecular sieve energy-saving system includes a heat exchanger 1, a nitrogen pipe 2 and an air pipe 3; the heat exchanger 1 includes a first air inlet, a first air outlet, a second air inlet and a second air outlet, the first air inlet is connected to a first air inlet pipe 11, the first air outlet is connected to a first air outlet pipe 12, the second air inlet is connected to a second air inlet pipe 13, the second air outlet is connected to a second air outlet pipe 14, the first air inlet pipe 11 is connected to a first control valve I15, the first air outlet pipe 12 is connected to a first control valve II16, the second air inlet pipe 13 is connected to a second control valve I17, and the second air outlet pipe 14 is connected to a second control valve II18 The nitrogen pipe 2 is connected with a first nitrogen control valve 21, a second nitrogen control valve 22 and a heater 23 in sequence according to the air inlet direction. The other ends of the first air inlet pipe 11 and the first air outlet pipe 12 are respectively connected to the nitrogen pipe 2, and the second nitrogen control valve 22 is located between the first air inlet pipe 11 and the first air outlet pipe 12. The air pipe 3 is connected with an air compressor 31 and an air control valve 32 in sequence according to the air inlet direction. The other ends of the second air inlet pipe 13 and the second air outlet pipe 14 are respectively connected to the air pipe 3, and the air control valve 32 is located between the second air inlet pipe 13 and the second air outlet pipe 14. The air outlet end of the air pipe 3 is also connected to a cooler 33.

[0016] As a preferred technical solution, the cooler 33 is a water-cooled cooler; the heat exchanger 1 is a shell and tube heat exchanger; and the heater 23 is an electric heater.

[0017] When the present invention is in use, nitrogen pipe 2 is fed with contaminated nitrogen generated in the air separation system, and air pipe 3 is fed with air. The air is compressed by air compressor 31 to a temperature of approximately 120°C. The compressed air and contaminated nitrogen then exchange heat in heat exchanger 1, with the contaminated nitrogen heated to approximately 70°C before entering heater 23 for further heating. This saves energy and reduces costs. The compressed air temperature drops to approximately 80°C before entering cooler 33 for cooling, which also reduces the workload of the cooler and conserves circulating cooling water. The air is compressed by air compressor 31 and then cooled by cooler 33, which is an existing process in the air separation system and does not add additional costs. Contaminated nitrogen is also an intermediate product of the air separation system and is already present, so it does not add additional costs (contaminated nitrogen refers to impure nitrogen containing a certain amount of oxygen and other impurities).

[0018] Energy saving comparison experiment

[0019] The energy-saving benefits of our company's 24000 air separation system after renovation were calculated. Before the renovation, a metering system consisting of a calibrated electric energy meter and an accumulated timer was used. Continuous measurement was performed for 30 days under normal production process conditions to calculate the total power consumption and average daily power consumption of the electric heaters in the molecular sieve purification system. After the renovation was completed according to the technical solution of the utility model, the system was put into use and continuous measurement was performed for 7 days under normal production process conditions to calculate the total power consumption of the electric heaters. Electric heaters 1# and 3# were selected for measurement. Both heaters were heated in three sections, with temperatures rising from low to high. The three heating sections correspond to the values ​​at the first, second, and third electric heating meters, respectively.

[0020] The power table of the electric heater before the transformation is shown in Table 1, and the power table of the electric heater after the transformation is shown in Table 2.

[0021] Table 1 Electric heater power before transformation

[0022]

[0023] Table 2 Power of electric heater after transformation

[0024]

[0025]

[0026] It can be seen from Table 1 that the total power consumption of the 1# and 3# electric heaters within 30 days is 63275+67589+29786+63136+61475+30709=315970kw·h. From this, it can be calculated that the average daily power consumption of the electric heaters before the transformation is 315970÷30=10532.33kw·h.

[0027] From Table 2, we can see that the total power consumption of the 1# and 3# electric heaters in 7 days is 16894+7236+13868+6991=44989kw·h. From this, we can calculate that the average daily power consumption of the electric heaters after the dirty nitrogen preheater is put into use is 44989÷7=6427kw·h.

[0028] Average daily power saving after transformation = average daily power consumption before transformation - average daily power consumption after transformation = 10532.33 - 6427 = 4105.33 kw·h

[0029] From the above calculation, we can get: Acceptance power saving rate = average daily power saving after transformation ÷ average daily power consumption before transformation * 100% = 4105.33 ÷ 10532.33 * 100% = 38.98%.

[0030] Assuming the system operates for 340 days a year and the electricity price is 0.63 yuan / (kw·h), the annual electricity savings are: 4105.33*340*0.63=879,000 yuan.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A molecular sieve energy-saving system, characterized by: include A heat exchanger comprising a first air inlet, a first air outlet, a second air inlet, and a second air outlet, wherein the first air inlet is connected to a first air inlet pipe, the first air outlet is connected to a first air outlet pipe, the second air inlet is connected to a second air inlet pipe, the second air outlet is connected to a second air outlet pipe, the first air inlet pipe is connected to a first control valve I, the first air outlet pipe is connected to a first control valve II, the second air inlet pipe is connected to a second control valve I, and the second air outlet pipe is connected to a second control valve II; A nitrogen pipe is connected to a first nitrogen control valve, a second nitrogen control valve and a heater in sequence in the air inlet direction, the other ends of the first air inlet pipe and the first air outlet pipe are respectively connected to the nitrogen pipe, and the second nitrogen control valve is located between the first air inlet pipe and the first air outlet pipe; The air pipe is connected to the air compressor and the air control valve in sequence according to the air inlet direction. The other ends of the second air inlet pipe and the second air outlet pipe are respectively connected to the air pipe, and the air control valve is located between the second air inlet pipe and the second air outlet pipe.

2. The molecular sieve energy-saving system according to claim 1, characterized in that: The air outlet end of the air pipe is also connected to a cooler.

3. The molecular sieve energy-saving system according to claim 2, characterized in that: The cooler is a water-cooled cooler.

4. The molecular sieve energy-saving system according to claim 1, characterized in that: The heat exchanger is a shell and tube heat exchanger.

5. The molecular sieve energy-saving system according to claim 1, characterized in that: The heater is an electric heater.

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