my scientific age

Chapter 256 Turbocharging!

In terms of status, the core front-end technology of oxygen top-blown converter technology is industrial-grade air separation equipment.

Historically, the first oxygen generator in the true sense 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 a great demand for nitrogen, and the oxygen generator began to produce oxygen and nitrogen. , renamed air separation equipment.

The working principle of the air separation equipment is very simple. Using the different boiling points of liquid oxygen and liquid nitrogen, the air is treated at low temperature, rectified and separated, and finally high-purity oxygen, high-purity nitrogen, and other useful gases are obtained.

At present, there is no real industrial-grade air separation equipment in the world. All air separation equipment is still at a small level, and its oxygen output is about 5-10 cubic meters per hour, which is far from meeting the needs of large-scale oxygen steelmaking. requirements, not up to industrial-grade standards.

The oxygen consumption of the 2T grade oxygen blowing furnace is about 1.5 cubic meters per minute per ton of metal, the smelting time is about 20 minutes, and the total oxygen consumption is as high as 60 cubic meters.

One side is a swimming pool of 180 cubic meters, and the other 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 too big.

To meet the standards of oxygen steelmaking, the oxygen production of air separation plants must increase by two orders of magnitude.

Yu Hua's goal is to develop an air separation plant with an oxygen output of more than 1000 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 lance first.

Air separation equipment is the core front-end technology of oxygen blowing furnace technology, and oxygen lance and refractory materials are the core technology of oxygen blowing furnace itself.

One link is another, and no place can be sloppy.

In the office, Yu Hua was working at his desk with a serious face. He kept drawing on the drawings with pens and tools in both hands. These are the design parameters and dimensional data of the flange parts of the three-hole oxygen lance nozzle. In order to meet the oxygen supply strength and pressure, the nozzle flange The material of the parts is cast iron and electric furnace steel, and the sealing and connection are realized by the submerged arc welding process.

After drawing the drawings of the flange parts, Yu Hua activated the thinking computer, and his eyes showed a touch of absolute rationality. He built a mathematical model of the flange parts in his mind, and then loaded the reference material and structure, as well as the high-pressure oxygen data, and then began to calculate and simulate.

Calculate and simulate the working conditions and data in the furnace of cast iron flanges and electric furnace steel flanges.

This is Yu Hua's unique advantage, a capability that countless scientists dream of.

In the mathematical model, a high-pressure pure oxygen moves along the central pipe at a high speed, surging like a turbulent flow. After reaching the flange of the nozzle, it exerts huge pressure on the flange of the cast iron material.

Although cast iron is inferior to 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.

The fiery red converter appeared, and the molten steel as high as more than 1000 degrees Celsius released a high amount of heat all the time, and the air heated up rapidly, covering the flange made of cast iron.

"Crack!" Under the dual influence of low-temperature cooling water and high-temperature heat waves, the cast iron changes rapidly, and the strength and hardness decrease at a speed visible to the naked eye. After only a dozen seconds, a crack occurs in the cast iron flange, high-pressure pure oxygen and low-temperature cooling The water leaked immediately.

Mathematical model calculation terminated.

"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 flanges, his face was calm, and after analyzing these simulation calculation data in his mind, he gave a preliminary conclusion, and then began to conduct 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 needs to calculate two mathematical models is to check whether the cast iron material can meet the requirements.

There is no way, the base is poor, China is poor, the cost of cast iron and the cost of electric furnace steel are completely two concepts. If the cast iron material can meet the use environment of the flange, there is no need to spend precious electric furnace steel.

Unfortunately, the result of the cast iron flange did not surprise Yu Hua.

The mathematical model calculation was started again, and the realistic variables such as high-pressure pure oxygen and the working process in the furnace appeared. This time, the flange plate made of electric furnace steel material ran stably in a near-real environment, and the working time reached more than ten hours.

"The mechanical data of the material is qualified, and the safety pressure margin is sufficient. In the case of cooling water, the steel flange of the electric furnace can run for a long time. In the case of no cooling water, it will change its material properties due to high temperature in about 10 minutes. However, 10 minutes is enough to damage the nozzle hundreds of times.” After running the dynamic calculation and simulation, Yu Hua obtained the material mechanics data and various parameters of the steel flange of the electric furnace, quit the computer mode of thinking that consumes a lot of money, and pondered silently.

This calculation data shows that there is no problem with the flange design, and EAF steel must be used.

The nozzle flange was completed, and the entire oxygen lance development project was basically over. Yu Hua marked the parts specifications and material requirements on the drawings, and then opened the drawer filled with dozens of design drawings, folded the flange design, and put it into it.

These design drawings in the drawer are all about the oxygen lance, including the overall three views, nozzle design drawings, gun body design drawings, etc. Don't think that there are dozens of them. In fact, engineers and scholars engaged in technology development in this era. , Drawings consume dozens of kilograms at every turn.

Yes, dozens or hundreds of kilograms.

This is not too much. If it is a super-difficult and complex engineering project, the consumption of drawings can even reach the ton-level standard.

Compared with his peers at the same time, Yu Hua's dozens of drawings are already considered super diligent and thrifty.

And these all rely on thinking computers and thinking approximate physical systems.

"Oxygen lance is done, take advantage of the energy now, let's study the air separation plant." Yu Hua put the blueprint away, transferred his mind from the oxygen lance to the air separation plant, rested for a while, then took out a blank drawing and placed it on the desktop.

The face of the whole person is a little serious, the right hand is holding a pen, and the working principle of the air separation plant and the oxygen production process are written on the scrap paper next to it.

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-rectification.

To produce oxygen from air, the first and most important step is to compress the air.

The question is, how to compress the air?
Very simple, the last metal body with internal space and closed, plus cast iron metal with smooth reciprocating surface, can realize compressed air, which can be called cylinder and piston in the field of mechanical engineering.

The cylinder and the piston are not enough. In order to transmit the energy to 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, it is fully sealed. The cast iron shell and inlet and exhaust pipes, a machine that can compress air is ready.

This is the air compressor.

From the perspective of mechanical engineering, the working principle of the compressor is very simple. For any high school science student in the future, as long as he listens to the class, understands it casually, and has strong hands-on ability, he can build a simple compressor.

And compressors are spread all over thousands of households. To give the simplest example, all the 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, the first stumbling block on the road to research and development is an irreplaceable compressor, whose work requirements and indicators far exceed those of air compressors and refrigerator compressors. In other words, if you want the entire air separation plant to produce enough oxygen, you must pay more than five times the effort.

The reason is simple, the oxygen volume fraction in the air is 21%.

It takes five parts of air to make one part of oxygen.

For the compressor, to meet the unit oxygen consumption of a minimum 2T-level 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 is a real 30-ton industrial oxygen blown furnace, it will be even more exaggerated.

The 30-ton oxygen blowing furnace not only means that the volume of molten steel increases, but also the unit oxygen consumption rises sharply, reaching 3.5 cubic meters per minute per ton of metal!
What is this concept?
The oxygen supply intensity should reach 6300 cubic meters per hour, and then multiply by 5 to get an astronomical figure of 3.15 cubic meters of air.

Of course, Yu Hua did not set his sights too high, and was ready to launch an air separation plant with a capacity of 7000 cubic meters per hour.

"At this stage, the oxygen production of air separation plants in the world is not high. The main reason is that the air intake of the compressor is not enough, and this depends on the air intake efficiency of the air intake unit..." Yu Hua held a pencil in his right hand and drew a few simple strokes. Come up with a minimalist air intake unit structure, and think at high speed.

Intake unit and intake efficiency!
The reason why the research and development of industrial-grade air separation equipment is difficult lies in the ultra-high oxygen production efficiency.

Since the compressor must obtain a huge amount of air all the time, the design of the air intake unit is very important. It is known that the higher the air intake efficiency, the higher the air intake capacity of the compressor.

A new question was born, what structural design of the air intake unit is the most efficient?
No one knows, this is the top concern of nitrogen fertilizer plant owners and oxygen cutting engineers.

Of course, Yu Hua still knows that the air intake unit with the highest air intake efficiency is only the compressor for the F22 vector turbofan engine on the F-119 'Raptor'. The air intake efficiency of this thing is terrifying. The intake air volume per second reaches more than one thousand cubic meters, so that the 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 aero engines.

Well, in theory, this is a super ideal compressor intake unit, if Yu Hua can build it.

The compressor with the F119 turbofan engine is too far away. When returning to the compressor sketch, Yu Hua weighed and considered it carefully. After careful consideration, he believes that the most suitable air intake unit for the compressor at this stage is the turbine composed of a centrifugal compressor and a turbine. Supercharging technology.

Yes, the famous turbo.

Turbocharging technology can effectively improve the air intake efficiency, and then meet the air intake demand of the compressor, which plays a vital role in the entire air separation plant.

Holding a pencil, Yu Hua drew a conceptual diagram of the turbocharger unit and compressor. At the same time, he began to calculate the data in his mind, and performed different data calculations for the single-stage compressor and the multi-stage compressor. 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 intake air volume is insufficient, only 780 cubic meters per hour, which still cannot meet the oxygen supply intensity requirements of the 2T experimental furnace.

The two-stage centrifugal compressor and turbine increase the intake efficiency by more than 30% compared with the single-stage, and the total intake volume is up to 1014 cubic meters per hour, meeting the needs of the 2T experimental furnace.

The three-stage centrifugal compressor and turbine increase the intake efficiency by more than 45% compared with the second stage, and the total intake volume is excellent, reaching 1470 cubic meters per hour.

This turbocharger technology, which was born in 1885, immediately changed the research of air separation equipment. As for the four-stage compressor and the fifth-stage compressor, considering the processing difficulty and material constraints, there is absolutely no need for computational simulation.

For the machinery manufacturing industry in 1937, centrifugal compressors with three or more stages were as out of reach as the F119 compared to Dawn.

"The first stage is not enough. The third stage centrifugal compressor has particularly high requirements on the manufacturing process and materials, and the cost is high and not cost-effective. Although the intake efficiency of the second stage is not as good as that of the third stage turbocharger unit, it is already suitable." Compressors of different structures are selected, and there is no doubt that the combination of a two-stage centrifugal compressor and a turbine is the most suitable for the current compressor.

(End of this chapter)