In terms of status, the core front-end technology of oxygen top-blown converter technology is industrial-grade air separation equipment.
Historically, the first true oxygen concentrator was born in late 1903 and was used for gas welding and cutting of metals. Later, with the rapid development of the nitrogen fertilizer industry, there was gradually a huge demand for nitrogen, and the oxygen concentrator began to produce oxygen and nitrogen.
, renamed air separation equipment.
The working principle of air separation equipment is very simple. It uses the different boiling points of liquid oxygen and liquid nitrogen to process the air at low temperature, distill and separate it, and finally obtain high-purity oxygen, high-purity nitrogen, and other useful gases.
At present, there is no real industrial-grade air separation equipment in the world. All air separation equipment is still at a small level. Its oxygen output is about 5-10 cubic meters per hour, which is far from meeting the needs of large-scale oxygen steelmaking.
requirements and cannot meet industrial-grade standards.
The oxygen consumption of a 2T-level oxygen blowing furnace is about 1.5 cubic meters per ton of metal per minute, the smelting time is about 20 minutes, and the total oxygen consumption is as high as 60 cubic meters.
On one side is a 180 cubic meter swimming pool, and on the other side is a small water pipe of about 5-10 cubic meters per hour. The gap between the two is 36-18 times, which is not a big deal.
To meet the standards of oxygen steelmaking, the oxygen production of air separation equipment must be increased by two orders of magnitude.
Yu Hua's goal is to develop air separation equipment with an oxygen output of more than 1,000 cubic meters per hour, so that it can meet the planned 2T-level experimental oxygen blowing furnace.
However, the top priority is to get the oxygen gun first.
Air separation equipment is the core front-end technology of oxygen blowing furnace technology, while oxygen lances and refractory materials are the core technologies of oxygen blowing furnace itself.
One link after another, no carelessness in every place.
In the office, Yu Hua is working at his desk with a serious face. He is holding pens and tools in both hands and is constantly drawing on the drawings. These are the design parameters and dimensional data of the three-hole oxygen lance nozzle flange parts. In order to meet the oxygen supply intensity and pressure, the nozzle flange
The parts are made of cast iron and electric furnace steel, and are sealed and connected through submerged arc welding.
After drawing the drawings of the flange parts, Yu Hua turned on the thinking computer, with an absolutely rational look in his eyes. He constructed a mathematical model of the flange parts in his mind, then loaded the base material and structure, as well as high-pressure oxygen data, and then began to calculate and simulate.
Calculate and simulate the furnace working conditions and data of cast iron flanges and electric furnace steel flanges.
This is Yu Hua's unique advantage, an ability that countless scientists dream of.
In the mathematical model, a stream of high-pressure pure oxygen advances at high speed along the central tube, surging like a turbulent flow. When it reaches the nozzle flange, it exerts huge pressure on the cast iron flange.
Although cast iron is not as good as electric furnace steel, it can easily withstand the pressure generated by this high-pressure gaseous pure oxygen. After the cast iron flange works for one second, the mathematical model introduces a new variable factor - the working environment in the furnace.
A fiery red converter appeared, with molten steel reaching a temperature of more than a thousand degrees Celsius, releasing high amounts of heat at all times. The air heated up rapidly and enveloped the flange made of cast iron.
"Crack!" Under the dual influence of low-temperature cooling water and high-temperature heat waves, the cast iron changed rapidly, and the strength and hardness decreased at a speed visible to the naked eye. After only a dozen seconds, a crack occurred in the cast iron flange. High-pressure pure oxygen and low-temperature cooling
The water immediately leaked out.
Mathematical model calculation terminates.
"Cast iron is not good, it seems that we can only use electric furnace steel." Yu Hua was not surprised by the simulation data of cast iron flange, with a calm expression. After analyzing the simulation calculation data in his mind, he gave a preliminary conclusion, and then began to conduct research on electric furnace steel materials.
Flange mathematical model calculation.
The mechanical properties of cast iron and electric furnace steel are obviously different, and the reason why Yu Hua made two mathematical model calculations was just to see whether the cast iron material could meet the requirements.
There is no solution. The base area is poor and China is poor. The cost of cast iron and the cost of electric furnace steel are completely different concepts. If the cast iron material can meet the use environment of the flange, then there is no need to waste precious electric furnace steel.
Unfortunately, the results of the cast iron flange did not surprise Yu Hua.
The mathematical model calculation was started again, and real variable factors such as high-pressure pure oxygen and working links in the furnace appeared. This time, the flange plate made of electric furnace steel ran stably in a nearly real environment, and the working time reached more than ten hours.
"The material mechanics data is qualified and the safety pressure margin is sufficient. In the presence of cooling water, the electric furnace steel flange can run for a long time. In the absence of cooling water, its material properties will change due to high temperature in about ten minutes.
However, ten minutes is enough to damage the nozzle hundreds of times." Yu Hua ran a dynamic calculation simulation and obtained the material mechanics data and various parameters of the electric furnace steel flange. He exited the hugely consuming computer mode and thought silently.
This calculation data shows that there is no problem with the flange design and electric furnace steel must be used.
The nozzle flange was completed, and the entire oxygen lance development project was basically completed. Yu Hua marked the part specifications and material requirements on the drawings, then opened a drawer filled with dozens of design drawings, folded the flange design drawings, and put them in it.
These design drawings in the drawer are all about oxygen guns, including the overall three-dimensional view, nozzle design drawings, gun body design drawings, etc. Don’t think that dozens of copies are a lot. In fact, engineers and scholars engaged in technology development in this era
, drawings can easily consume tens or hundreds of kilograms.
Yes, dozens or hundreds of kilograms.
This is not much. If it is an engineering project that is extremely difficult and complex in structure, the consumption of drawings can even reach the ton level.
Compared with his peers at the same time, Yu Hua's dozens of drawings are already considered to be extremely diligent and thrifty.
And these all rely on thinking computers and thinking-approximate physical systems.
"The oxygen lance is finally done. Let's study the air separation equipment while we still have energy." Yu Hua put down the drawings and shifted his thoughts from the oxygen lance to the air separation equipment. He rested for a while, then took out a blank drawing and placed it on the air separation equipment.
desktop.
The person's face was somewhat serious. He held a pen in his right hand and wrote down the working principle of the air separation equipment and the oxygen production process on the scratch paper next to him.
The principle is to use the different boiling points of oxygen and nitrogen to produce oxygen. The oxygen production process is roughly divided into compression-purification-heat exchange-refrigeration-distillation.
To produce oxygen from air, the first and most important step is to compress the air.
The question is, how to compress air?
It's very simple. A closed metal body with an internal space and a cast iron metal with a smooth reciprocating surface can achieve compressed air. In the field of mechanical engineering, it can be called a cylinder and a piston.
The cylinder and piston alone are not enough. In order to transmit energy and make the piston run, a crank connecting rod must be installed to connect the energy supply core. This point is provided by the motor that converts electrical energy into mechanical energy. After that, a complete seal is installed.
With the cast iron shell and inlet and exhaust pipes, a device that can compress air is ready.
This is the air compressor.
From a mechanical engineering perspective, the working principle of a compressor is very simple. For any future science high school student, as long as he listens to the class, understands it casually, and has strong hands-on ability, he can build a simple compressor.
Compressors are found in thousands of households. To take the simplest example, all air conditioners and refrigerators in every household in later generations rely on compressors for refrigeration.
However, as the heart of industrial-grade air separation equipment and the first stumbling block on the road to research and development, the irreplaceable compressor has working requirements and indicators that far exceed those of air compressors and refrigerator compressors. Moreover, for compressors
Generally speaking, if you want the entire air separation equipment to produce enough oxygen, you must put in more than five times the effort.
The reason is simple, the oxygen volume fraction in the air is 21%.
To produce one part of oxygen, five parts of air are needed.
For the compressor, to meet the unit oxygen consumption of a minimum 2T-class experimental oxygen blowing furnace, that is, the oxygen output of 180 cubic meters per hour, it must be directly multiplied by five times.
If it were a true 30-ton industrial oxygen blowing furnace, it would be even more exaggerated.
The 30-ton oxygen blowing furnace not only means an increase in the volume of molten steel, but also a sharp rise in unit oxygen consumption, reaching 3.5 cubic meters per ton of metal per minute!
What is this concept?
The oxygen supply intensity must reach 6,300 cubic meters per hour, and then multiplied by 5 to get the astronomical figure of 31,500 cubic meters of air.
Of course, Yu Hua did not aim too high and planned to directly launch a 7,000 cubic meter per hour air separation equipment. He was down to earth and started from a small perspective, with the goal of setting an air separation equipment of 200 cubic meters per hour of oxygen.
"At this stage, the oxygen production of air separation equipment around the world is not high. The main reason is that the air intake volume of the compressor is insufficient, which depends on the air intake efficiency of the air intake unit..." Yu Hua held a pencil in his right hand and drew with a few simple strokes.
I came up with an air intake unit structure with a minimalist style, and my mind was thinking at high speed.
Air intake unit and air intake efficiency!
The reason why the research and development of industrial-grade air separation equipment is difficult lies in its ultra-high oxygen production efficiency.
Since the compressor must obtain a huge amount of air at all times, the design of the air intake unit is crucial. It is known that the higher the air intake efficiency, the higher the air intake volume of the compressor.
A new question arises from this: What structural design of the air intake unit is the most efficient?
No one knows, this is what nitrogen fertilizer factory owners and oxygen cutting engineers are most concerned about.
Of course, Yu Hua still knew that the only known air intake unit with the highest air intake efficiency was the compressor used in the F119 vector turbofan engine of the F-22 Raptor. The air intake efficiency of this thing is terrifying.
The air intake volume per second reaches more than thousands of cubic meters, so the air intake efficiency of this small bypass ratio turbofan engine is not weaker than that of the large bypass ratio turbofan engine, and the thrust is the highest among aeroengines.
Well, in theory, this is a super ideal compressor air intake unit, if Yu Hua can build it.
Using the compressor of the F119 turbofan engine is too far away. Returning to the compressor sketch, Yu Hua weighed and considered it. After careful consideration, he believed that the most suitable air intake unit for the compressor at this stage is a turbine composed of a centrifugal compressor and a turbine.
Supercharging technology.
Yes, the famous turbocharger.
Turbocharging technology can effectively improve the air intake efficiency, thereby meeting the air intake demand of the compressor, and plays a vital role in the entire air separation equipment.
Yu Hua held a pencil and drew a conceptual diagram of the turbocharger unit and compressor. At the same time, his mind began to calculate data, performing different calculations on single-stage compressors and multi-stage compressors. After a few minutes, Yu Hua got
A series of data results.
The calculation simulation results show:
The single-stage compressor and turbine effectively improve the air intake efficiency, but the total air intake volume is insufficient, only 780 cubic meters per hour, which still cannot meet the oxygen supply intensity demand of the 2T experimental furnace.
The two-stage centrifugal compressor and turbine increase the air intake efficiency by more than 30% compared with the single-stage, and the total air intake volume is qualified, reaching 1014 cubic meters per hour, meeting the needs of the 2T experimental furnace.
The three-stage centrifugal compressor and turbine increase the air intake efficiency by more than 45% compared with the second stage, and the total air intake volume is excellent, reaching 1470 cubic meters per hour.
This turbocharging technology, born in 1885, instantly brought about earth-shaking changes in the research of air separation equipment. As for the four-stage compressor and the five-stage compressor, considering the processing difficulty and material limitations, there is no need for computational simulation at all.
Three-stage or higher centrifugal compressors were as out of reach to the machinery manufacturing industry in 1937 as the F119 was to Dawn Aircraft.
"The first stage is not enough. The three-stage centrifugal compressor has extremely high requirements on manufacturing technology and materials, is high in cost, and is not cost-effective. Although the air intake efficiency of the second stage is not as good as that of the three-stage turbocharger unit, it is already suitable." Yu Hua expressed his opinion on the use of three types of compressors.
When choosing compressors with different structures, there is no doubt that the combination of a two-stage centrifugal compressor and a turbine is the most suitable for current compressors.