Liang style kiln is a modern lime production kiln on the international market. It was introduced into the domestic market from abroad in the early 1990s. After continuous R&D and improvement after localization, our company now has complete intellectual property rights. Over the years, the promotion and technical progress of beam kiln have made great contributions to the development and progress of lime industry. According to incomplete statistics, so far, there are 278 beam kilns in the international market, including 8 exported by China, with a capacity of 28 million tons. There are 448 beam kilns in the domestic market with a capacity of 40.5 million tons. According to the total capacity of 360 million tons of international lime, the capacity of beam kiln accounts for 19.03% of the total capacity. Such a huge market share fully demonstrates that the market competitiveness of beam kiln is very strong.

One beam kiln has the following characteristics:

1) Simple structure

Beam kiln belongs to single chamber shaft kiln with simple structure.

2) Strong adaptability to raw materials

It is possible to use raw materials of various sizes in the current market. For customers with their own mines, it can maximize the utilization efficiency of raw materials.

3) Wide range of fuels

The fuel available for beam kiln is the most widely used in the world. The fuels that can be used are as follows:

☆ Gas fuel: natural gas, coke oven gas, converter gas, blast furnace gas, producer gas, coke oven gas, yellow phosphorus furnace gas, calcium carbide furnace gas, biomass gas, or mixed gas.

☆ Solid fuel: bituminous coal, lignite, coke powder, bio powder fuel, etc.

☆ Liquid fuel: heavy oil, light oil, etc.

☆ Composite fuel: gas+pulverized coal; Gas+oil; Low calorific value gas+high calorific value gas and other mixed fuels.

4) Simple operation reduces a lot of labor costs

The operation is relatively simple, which can save a lot of labor costs.

5) Excellent quality index

The quality index has reached the world's advanced level and can be used in the production of various active limes.

6) Excellent environmental indicators

The environmental protection indicators can meet the requirements of all countries in the world.

7) Good operability

The beam kiln can be adjusted arbitrarily between 40% and 110% of the design capacity to ensure stable performance.

8) High cost performance

Its cost is more than 1/3 lower than that of other modern kilns, which is the most popular among customers.

9) The beam kiln technology can be used to directly transform and upgrade the ordinary mechanical vertical kiln to achieve technical upgrading.

10) High degree of automation

The beam kiln is controlled by PLC, realizing the automatic operation mode of the equipment.

Core technology concept of two beam kiln

1) Combustion beam

Basic definition of combustion beam: it is a thermal tool to provide industrial furnace with controllable heating intensity and fuel distribution area.

Providing controllable heat supply intensity means that the combustion beam adopts different burner forms and sizes in design according to the size of the kiln or different fuels, and configures adjustable fuel supply and air fuel ratio to achieve the control of heat supply intensity. At present, the heating capacity of a combustion beam on the market is 3.92~14.5GJ/h.

The fuel distribution area refers to that the combustion beam can be designed with different layout spacing and burner spacing according to the size of the kiln and different fuels, so that the fuel can be distributed to different areas to achieve the best layout effect of lime calcination. The combustion beam is designed with different number of burners according to different fuels in the length direction, and runs through the whole kiln. According to the section size of the kiln chamber, a kiln can be equipped with multiple combustion beams, which are arranged in two layers, so that each burner can cover the whole cross-section of the kiln chamber. The burner sprays fuel into the beam kiln chamber from the nozzle hole of the combustion beam, and combustion air is sprayed into the beam kiln chamber from the nozzle hole of the combustion beam. The flame generated by the mixture of the two directly conducts lime calcination. Dozens or hundreds of burners in the whole kiln section are calcined at the same time, realizing the thermal effect of uniform calcination in the thermal field of the whole kiln.

Combustion beams can be designed into different sizes and different structural forms. With the continuous progress of technology, there are many types of combustion beams on the market.

The types of combustion beams can be summarized into three categories:

The first type is the conventional type: oil cooling or water cooling, and the main structure is the combustion beam of alloy steel welding structure;

The structure of this type of combustion beam includes rectangular combustion beam, T-shaped combustion beam, double T-shaped combustion beam, F-shaped combustion beam, etc. The length of combustion beam is designed according to the needs of beam kiln section, which is generally 4~8m, depending on the design section size. The middle of the combustion beam is a cavity, and the bottom of the rectangular combustion beam (two sides of the T-shaped combustion beam, double T-shaped combustion beam, and one side of the F-shaped combustion beam) is provided with a nozzle hole. A burner is installed inside the cavity, and the fuel is sent into the kiln through the burner. The space outside the burner conveys combustion air, which is sent into the kiln from the nozzle hole. In the kiln, the fuel and combustion air are mixed and burned, and the limestone around each burner is effectively calcined.

The structural diagram of rectangular combustion beam is shown in the following figure. T-shaped double T-shaped or F-shaped burners are used for side spraying, and the principle is the same.

The combustion beams used in the first and second generation beam kilns are all alloy steel composite welded structures, which are cooled by heat transfer oil or water. Heat from heat transfer oil or water circulation is discharged into the atmosphere by fans. The first generation beam kiln will probably cause heat loss of about 150~200Kcal/(kg · finished ash). The second generation beam kiln may cause heat loss of 200~250Kcal/(kg · finished ash). Some large-scale enterprises use this heat to generate electricity, which maximizes the utilization of resources. Most enterprises do not recover this heat.

The second type is thermal insulation type: oil cooling or water cooling is adopted, and the main structure is thermal insulation combustion beam made of refractory and steel composite materials (national invention patent ZL201410094521.8);

The third generation beam kiln adopts an adiabatic combustion beam. The main body of the adiabatic combustion beam is made of composite materials of refractory and steel, which aims to reduce the heat loss of heat transfer oil or water. The third generation beam kiln may cause heat loss of 20-30Kcal/(kg. finished ash). The adiabatic combustion beam is a national invention patent (ZL201,410,094,521.8). The picture below shows the adiabatic combustion beam.

Picture of combustion beam device of the third generation beam kiln (this picture is a T-shaped combustion beam side injection mode)

The third type is air cooling type: the air cooling type is adopted, and the main structure is an adiabatic combustion beam made of refractory and steel composite materials (national invention patent ZL201610004568.9);

The fourth and fifth generation beam kilns use air-cooled combustion beams. The combustion beams are cooled by combustion supporting air. The combustion supporting air preheated by the combustion beams directly participates in combustion, completely eliminating the heat loss of the combustion beams. The air-cooled combustion beam is the most revolutionary invention in the history of beam kiln technology development. It completely eliminates the heat loss caused by the self cooling of the combustion beam, completely eliminates the potential safety hazards of the oil cooling beam, and realizes the zero loss of the combustion beam itself and the maximization of the overall thermal efficiency of the beam kiln. This technology has laid a solid foundation for the beam kiln to achieve the leading heat consumption index technology.

2) Beam kiln

Basic definition of beam kiln: it is a modern lime production kiln with burning beam as the core technology and equipment to calcine lime. Using combustion beam as thermal tool is the core feature of beam kiln. This is the main basis for judging beam kiln. The use of combustion beam technology makes the whole section of lime kiln calcined evenly and effectively. It is one of the advanced technologies of lime calcination technology. The use of combustion beam has a variety of different forms and functions. Beam kiln is a set of integrated production system from raw material feeding to finished product storage. The above definition is a high summary of its core technology.

Layout of combustion beam, ash outlet and suction beam of beam kiln

The design concept of beam kiln is to arrange combustion beams on the section of lime kiln to directly transport fuel to the required position of the whole section. The layout of combustion beams and burners shall meet the uniformity requirements of the whole section as far as possible. All parts of the whole section of lime kiln can be calcined evenly and effectively to produce high-quality lime. The design concept of beam kiln is relatively advanced, which not only solves the problem of lime calcination uniformity, but also realizes the design of large section. Up to now, the beam kiln has already achieved the capacity of 600t/d. In recent years, the beam kiln with larger unit output has been successfully developed and is being promoted in all aspects.

Beam kiln is a complete integrated production system, mainly including the following subsystems: feeding system; Kiln body system; Fuel supply system; Combustion beam system; Air supply system; Exhaust gas dedusting system; Ash discharging system; Electrical automation system; Peripheral supporting system.

The combustion beam used in the combustion beam system works in the thermal zone above 1000 degrees. It needs cooling protection. Therefore, the combustion beam must be equipped with corresponding cooling system if it wants to reach the normal service life. The combustion beam system mainly consists of two parts, namely, the combustion beam and its matched burner group, and the combustion beam cooling system that provides cooling medium for the combustion beam. At present, the cooling forms of combustion beam mainly include heat transfer oil cooling system, water cooling system and air cooling system. Oil cooling or water cooling has been used for decades, and its performance is stable and reliable. Its disadvantage is high heat loss. There is also a fire risk when heat transfer oil is used for cooling. After 2014, the adiabatic combustion beam began to be put into the market, and oil cooling or water cooling was still used, reducing the heat loss by 70%. The application of this technology has promoted the technical progress of beam kiln. After 2019, the air-cooled combustion beam will be put on the market to completely eliminate the heat loss. This technology has brought a complete revolutionary progress to the beam kiln, resulting in four generations of beam kiln technology. At present, the fourth generation beam kiln has been upgraded in several lime kilns, running stably and creating huge benefits for the owner.

The fuel supply system is divided into three categories: gas fuel supply system; Solid fuel supply system; Liquid fuel supply system. Some units use two kinds of fuels to mix, and the common ones are mixed gas with different calorific values, gas and pulverized coal.

Peripheral supporting systems vary greatly, such as raw material screening, storage and transportation system, finished product crushing, screening, storage and transportation system, supporting environmental dust removal system, gas transportation system, etc. Different enterprises have different needs. The configuration of these systems is based on the auxiliary configuration of the core production line, and more or less are selected according to the actual situation on site, without affecting the core functions of the beam kiln.

Beam kiln is a modern kiln in the international market today, which has been developed for decades, and has a history of nearly 30 years in China. After years of practice and technical progress, the beam kiln has gradually developed from the first generation introduced to the second generation, the third generation, the fourth generation and the fifth generation.

The 5th generation beam kiln is a large-scale shaft kiln - our company defines it as the beam sleeve kiln, abbreviated as CAB, with a capacity of 800~1500t/d, which is by far the highest unit output lime shaft kiln, with the patent number of ZL201911026606.1. A separate introduction follows.

3) Introduction to various generations of beam kilns

a) First generation beam kiln