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Guangxi Liuzhou Iron and Steel 15000m3 / h air separation plant air separation from the Kaifeng Group
Design, manufacture, using liquid oxygen, liquid argon within the compression process, is
The company's first set of liquid oxygen is compressed to 2.5MPa (gauge pressure, the same below)
Pressure rating 15000m3 / h air separation unit within the compression process. Liquid
Oxygen, liquid argon through the liquid pump pressure after the main heat exchanger re-heat, evaporation, after
To 2. OMPa (Liuzhou Iron and Steel oxygen pipeline pressure) the pressure of sending cold box.
Other configurations are: aluminum oxide layer at room temperature molecular sieve adsorption purification, in the
Pressure pressurized turbo-expander, non-hydrogen-argon, bath-type main condenser. 2003
Years, put into production in May, has been in the safe operation of more than a year. Now
15000m / h air separation equipment, technical characteristics and operational situation, and so ordinary
Shao, for peer reference.
An air separation equipment, the technical characteristics of
1.1 Process Description
15000m3 / h air separation unit within the compression process of the process, such as
As shown in Figure l.
Pressurized air through the air compressor, purifier purification were divided into two shares,
Yi Gu The plate-fin primary heat exchanger (E1) heat exchangers, cooling directly after
Into the next column; another unit by Booster (TC2) pressurized to 4.4MPa
And then divided into two stocks, a surge of walking the main plate-fin heat exchanger (E2) and
In the expansion mechanism for removing cold air into the post-expansion under the tower, another stock by
Expander Booster side (ET2) after 5.8MPa pressure into the pressurized
Plate-fin primary heat exchanger (E2), has been cooled to liquid state into the
Under the tower.
Unit operating conditions in the three kinds of production: large oxygen condition,
Larger liquid nitrogen liquid nitrogen liquid oxygen at the same time working conditions and production conditions, three kinds of working conditions
The actual production parameters in Table l.
Table 1 15000m. / H air separation unit within the compression process production parameters m3 / h
Conditions of nitrogen gas-liquid nitrogen liquid oxygen liquid oxygen, argon
Condition 1 l6l6O l50o l5000 600 620
Condition 2 l20 () 0 2l0o l50 () 0 600 445
Condition 3 l350o 600 l50 () 0 230o 440
Note: The liquid has been converted into a gaseous state, the data are under the state standard.
1.2 Energy Consumption Analysis
Pros and cons of the main air separation plant is to see product yield, purity and capacity
Energy consumption of these three products, including energy consumption should be a key determinant, because
Accounts for the energy consumption of air separation for more than the cost of production, energy saving can reduce the
Production costs and increase efficiency. Measured a real and effective and reliable machine
Unit energy consumption, for the guidance unit daily production of new regulation and Liuzhou Iron and Steel in the future
Selection of equipment over the points of guiding significance (for ease of calculation and with the
Other units of comparison, energy consumption calculation in order to shaft power meter, low-temperature liquids are
To three times the volume).
All air separation plant in the operation of equipment, power:
(Including air compressor, pressure machine),
Processing air volume:.
Product Data: gas oxygen (.), Liquid oxygen
(Off standard gas, the same below), liquid nitrogen,
Liquid argon, in order to assess the value of boot.
Unit of oxygen consumption: =. ·
Kaifeng Air Separation Group Company in the tender and operating technical specifications
Crew did not indicate energy consumption, there is no design parameters can be compared, there is no
There is running the same level of external compression process and compression process machine
Group for comparison, can only be selected in operation since the first
6 on behalf of external compression process unit to compare the operating parameters (see Table 2).
Table 2 Liuzhou Iron and Steel 1. Within the compression process an air separation plant energy consumption, with some of the outer compression process an air separation plant comparison of energy consumption,
Unit capacity units (production time, oxygen consumption (·) pressure of oxygen consumption (·) comprehensive energy consumption (

*)
Sanming Iron and Steel Company l 0 () 00 2001.5 ● Not available
Jinan Baud gas 2O0o0 2o02.3 O. 42 O. 16 O. 58
Baoshan Iron and Steel 30 () 00 2002.12 O. 42 information is available on
Zhangjiagang Hongchang Gas 2l 【x】 O 2o03.3 O. 39 O. 18l ●
Xinyu Iron and Steel Company l8 【x】 O 2003.4 O. 43 ● O. 607
1.2.1 Analysis of the parameters in Table 2 can be clear is this: the sixth generation of foreign
Compression process oxygen consumption in general. · Around, Canada
On the pressure of oxygen consumption, while energy consumption per unit of oxygen. · Left
Right.
1.2.2 Liuzhou Iron and Steel compression process an air separation plant energy consumption
Is not high due primarily to:
(1) air compressor, pressure machine, medium-pressure supercharger Expander for imports
Products, such as temperature, high efficiency, expander efficiency booster end,
Expansion-side efficiency of 85%.
(2) plate-fin heat exchanger for the main imported products, the temperature difference is small,
Low-pressure main heat exchanger hot-side temperature can be controlled within 0.5 ℃, high-pressure main heat exchanger
Thermal-side temperature can be controlled within 1.5 ℃, less heat loss is not reversible.
(3) expansion of air into the tower under the high flow of oxygen, argon mention
Take rate, means that product unit energy consumption down.
(4) The larger the liquid extraction rate, the total amount of cryogenic liquid oxygen gas
Volume l8.88%.
1.2.3 Liuzhou Iron and Steel 15000m3 / h air separation unit within the compression process energy consumption
Only indicate that it is not high power consumption is reasonable, is with conventional external compression
An air separation process of different production processes. Users should be based on their own
Demand option is used within the compression process, or outside the compression process, in the
Is equipped with the same compression transmission equipment, under the premise of selecting a foreign compression process
The comprehensive energy consumption will be lower?, But the bulky oxygen pressure turbine
Shrinking machine maintenance workload, the liquid production capacity is limited; selection pressure
Reduction process, the comprehensive energy consumption was higher, but the equipment to maintain a small amount of liquid
Large body capacity.
At present a considerable number of the oxygen capacity of iron and steel enterprises are significantly higher than the rule of
Refining requirements, oxygen Bleeding rates were more than 5% year round. If the new on the
After the air separation plant oxygen production is still off, use compression process for the
好. Because the liquid yield, a critical moment can turn on low-temperature liquid
Pumps, pressure vaporization of the liquid outside the delivery, as the smelting system using gas peaking hand
Segment, but also to meet the external gas sales, increasing economic benefits, than the re -
The last set of liquefaction equipment, the economic recovery of oxygen diffuse.
1.3 Instrument control system operation and stability
DCS systems are HONEYWELL's TPS system (that is
TOTAL PLANT SOLUTION, the whole factory integrated solutions
Abbreviation), is TDC3000 system while retaining the same advantages of
When a new generation of products using the latest technology. It
WINDOS2000 for the work environment, with the plant information management, open
Fang network environment, efficient and flexible application platform and Performance Management Control
System characteristics such as running more stable than TDC3000, if the system
In the regulatory function of automatic load tracking is even more ideal.
1.4 Extraction of the high rate of oxygen and argon, the product of high purity
The level of output depends on the unit of argon product yield and purity of oxygen
As well as the amount of argon-argon-containing fraction of the amount of the expansion of the air all of this unit
Participation into the next tower distillation tower, expansion gas from distillation of basic working conditions
The impact of all materials on the tower is the result of things over the next distillation tower
Materials, including argon-argon fraction more than the amount of up to l3%, so the extraction of argon
Rate is relatively high. After calculation, oxygen, argon extraction rates were as high as
99% and 84.43%, oxygen, argon product purity of 99.9% and
99.999%, argon in the oxygen and nitrogen content of less than 1 × 10 ~.
1.5 security unit operation is good
Air separation plant to safe production, the most important is to prevent the main condenser in
Hydrocarbon accumulation and exploded. This set of units with bath-type
Main cold, cold liquid oxygen out from the main booster, complex heat, evaporation sent, because
This accumulation of hydrocarbons in the main cold, concentration, crystallization, precipitation of
The possibilities are almost zero. At the same time as the main cold water bath-type oxygen cycle times
Rate of more than l0, thermal siphon effect of the liquid oxygen recycling can be established
More effectively use oxygen oxygen erosion channels, so that CO, NO distribution
The concentration of uniform, prevent CO, NO solid-state precipitation, plug the
Caused by "dead-end boiling," so the main cold-safety very stable.
In addition, with the small size of the cryogenic liquid oxygen pump to replace the oxygen turbine
Compressors, host room space has become very spacious, oxygen pressure system, fuel
To minimize the risk of explosion limits, security, greatly increased.
The operation of two air separation plant
2.1 Air, pre-cooling and purification system, a stable operation, high efficiency
2.1.1 stable compressor operation
Air compressor for the Demag company's products, three centrifugal compression
Machine. As a result of highly efficient self-cleaning air filters and air compressor bag
Impeller Water Jet Cleaning (cleaning cycle for five days, wash water
For the 2000L distilled water). Run over the past year, the air compressor vibration value
Remained stable, there is no upward trend. The location of the empty iron and steel enterprises
Air quality are not very good, so configure the compressor impeller water jet-ching
Cleaning system is necessary. '
To do: on each of the impeller a fountain cleaning, fountain
Speed of 45L/min. The cleaning process without preconditions, without examination
Consider whether the purification system to switch, but also do not need to do a protective air compressor
Regulation.
2.1.2 Pre-cooling system, high efficiency heat exchanger
Air-cooling towers and water cooling towers used in all packing tower, heat transfer efficiency
Rate. Air out the tower temperature was controlled at l0 ℃ below the water tower down
Temperature range up to 20 ℃. Even the hottest summer in Guangxi
(Daily average temperature of 30 ℃) a cooling tower water temperature can be lower than the
l3 ℃. Chillers are only opened three compressors can be fully satisfied
Production needs.
2.1.3 purification system switching stability
Purification system uses horizontal, two-tier structure, each purifier equipment
4 × 8 mesh molecular sieve 20t, alumina 12t, using a phased filling pressure,
Order to reduce the molecular sieve purification system when filling pressure distillation systems.
The daily production of the Air, pre-cooling and purification systems are all implemented
Automatic adjustment, under normal circumstances people do not need to adjust.
2.2 Liquid easy to adjust the working conditions of production
Within the compression process and the external compression process in the mass production of liquid when
The biggest difference is: within the compression process is only open one expander, not
Expansion of air pollution to go with the part of the nitrogen tube, do not need to increase the expansion machine
Speed. As the compression process in process configuration of the advantages, medium pressure
Expander efficiency, cooling unit volume, by the tower to re-sub -
Equipped with cold and adjustment, you can quickly change the liquid oxygen, liquid nitrogen production.
Larger more liquid nitrogen liquid oxygen conditions to the majority of working conditions is to
Cold transfer from the tower on the lower part of the upper tower, gas and oxygen production is not keeping
Variable (in order to maintain the plate-fin primary heat exchanger heat load constant), with the
Attention to the tower when the reflux ratio control, to avoid affecting the purity of nitrogen gas.
Conditions to adjust the steps: step by step off a small oxygen discharge valve gradually opened
Discharge valve to reduce a large liquid nitrogen gas production in a nitrogen gas when necessary, oxygen, liquid oxygen
Remove the valve further fine-tuning. Working conditions in the adjustment process in pure oxygen on the tower
Degrees, nitrogen purity, purity of sewage nitrogen, argon and the crude argon fraction the amount of crude argon
Oxygen content will not be a major fluctuations will not affect the main tower and argon column
Distillation conditions stability.
2.3 argon fraction simple adjustment
Argon fraction to adjust the range of 9.5% ~ 13%, and due to internal
Compression process of product oxygen in liquid state is drawn from the tower bottom
, The liquid oxygen out of a small amount of increase or decrease in the amount not affect the return to the previous tower
Ratio (that is, the main cooling effect of evaporation is not), does not cause the tower
Distillation conditions major changes, so it does not affect the composition of argon fraction
Great. At the same time the characteristics of compression process can not be significantly frequent transfers of
Out the entire amount of liquid oxygen, so the amount of oxygen through product purity and to adjust the
The role of argon fraction is not obvious, mainly through the amount of nitrogen and nitrogen
To adjust the purity argon fraction, of course, adjust the effect of delay in the adjustment than the Oxygen
Some, but the adjustment method is simple and effective, this point is not outside the compression process
The same. Kaifeng Air Separation Group, designed the addition of a diameter of
150mm oxygen out of gas pipeline, from the main cold air out of the upper part of oxygen, and
Nitrogen from the sewage discharge pipe, but the actual operation had never used.
2.4 The cycle of crude liquid argon pump switch, temporary parking and then start the main
Tower greater impact working condition
Crude liquid argon circulation pump to start again after the switching and parking will cause
Crude argon column (C5) at the bottom of the sharp fluctuations in crude liquid argon, on the tower
※ ※
Argon-pumped population fraction is also substantially below the return flow fluctuations, thus affecting the
On the tower operating conditions, such as the oxygen purity, argon fraction composition. There is no more
A good solution. If the crude argon column at the bottom of the tower back into the rough
Liquid argon to install a valve or pipe the crude liquid argon circulation pump speed control motors
Speed reduction can reduce the impact.
2.5 the amount of oxygen should not be frequent adjustments
Within the compression process to ensure that the plate-fin heat exchanger main heat exchanger complete
And the main tower distillation system, the stability conditions, oxygen pressure must be stable, that is,
Liquid oxygen through the main heat exchanger volume and pressure should be stable, note compression
Process Off-design operation should not be frequent, which is to protect the main change in plate-fin
Heat needs. This is for the large fluctuations in oxygen pressure often
The iron and steel enterprises is a contradiction, but also lack of points, oxygen pipe network
2.0MPa pressure is high only in high-pressure venting, resulting in waste of energy.
Of course, this problem in a multi-unit, composed of a variety of air separation process
Large iron and steel enterprises oxygen supply pipe network can be resolved: the high pressure pipeline network
When a quick stop oxygen compressor to stop pipe network for the medium-pressure oxygen, a separate
By the compression process an air separation plant oxygen.
3 Conclusion
Liuzhou Iron and Steel 15000m / h air separation unit within the compression process over a year
Multi-operation, showing equipment, stable operating conditions, liquid yield large
Features, adjust the amount of operation is small, simple means of regulation, the priorities
Point. The first kit-based compression process an air separation plant in successful operation,
Liuzhou Iron and Steel in 2005 on a new set of 28000m / h air separation plant has also adopted the
With the compression process.