The most popular energy-saving achievements of Chi

2022-07-24
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As we all know, the technological process of titanium dioxide by sulfuric acid method is very long, and naturally it consumes a lot of energy. However, as a fine chemical product, the total output of titanium dioxide at home and abroad is not much, which is not very noticeable. In fact, in terms of energy consumption per ton of products, it is far more than the unit consumption of steel, cement and other products, which are known as major energy consumers. The total output of these products is tens of millions of tons, or even hundreds of millions of tons. The total energy consumption sounds really frightening

energy saving achievements of China's titanium dioxide industry in recent years

there is a large difference in energy consumption when using different raw material routes for production (including the energy consumption during raw material enrichment production). Table 2 shows the comparison of energy consumption when using four different raw material routes to produce titanium dioxide

the energy consumption required for surface treatment is not included in the above four different process routes. For titanium dioxide with surface treatment process, an additional 83~120kmj/ttio2 is required according to different surface treatment processes. Titanium dioxide production consumes a lot of energy, and naturally accounts for a large proportion in the production cost. Generally, the expenditure of energy consumption accounts for 20%~25% of the production cost. Therefore, saving energy and reducing energy consumption is one of the important measures to reduce production costs, improve economic benefits and sustainable development

after the reform and opening up, China's titanium dioxide production has continued to grow at a high speed, and has also made many achievements in energy conservation and consumption reduction. Here are some examples:

1 ilmenite was crushed by 4R or 5R Raymond mills in the past. After the 1990s, drawing on the experience of imported projects, most enterprises with a scale of more than 15000 t/a have changed to wind swept mills. Compared with Raymond mills that are said to paint mineral oil, paint or burn enamel, spray plastic on the surface of iron products, The air swept mill has the advantages of large output, less maintenance and easy control. The power consumption per ton of mineral powder can be reduced by 5~10kwh

2 crystallization of ferrous sulfate at present, almost all domestic factories above 10000 tons have changed from freezing crystallization to vacuum crystallization, In recent years, many factories have changed from the original single-stage ejector - water ring true "Up to now, the air pump system has been changed to a two-stage ejector - water ring vacuum pump system. With the same power of the vacuum pump, the steam consumption can be reduced by 15% and the circulating water volume can be reduced accordingly. When a domestic plant adopts a single-stage ejector system, the steam consumption for each batch of titanium crystallization is 2330kg. After switching to a two-stage ejector system, the water ring vacuum pump is also 22KW, and only 1900kg steam is required for each crystallization of titanium.

3 Pressure hydrolysis has basically replaced its own seed hydrolysis process. The concentration of titanium solution hydrolyzed by its own seed requires the calibration and adjustment of the force measurement system of 230 electronic tensile testing machine, g/l, and the production is difficult to control; The concentration of titanium liquid in the process of adding crystal seeds only needs 195~200g/l. According to the consumption of 1.25Kg steam for evaporating 1kg water, about 900kg steam can be saved per ton of titanium liquid. The total production cost is still lower than that of its own crystal seeds except the consumption of gangue from adding crystal seeds. As the concentration of titanium liquid decreases, the heating area of the concentrator, power consumption and circulating water consumption decrease accordingly

4 application of diaphragm plate and frame filter press the diaphragm plate and frame filter press has replaced most vacuum leaf filters and drum filters for primary, secondary and tertiary water washing and dehydration before kiln and drying, which has made a great contribution to the energy saving of titanium dioxide. Especially in terms of dehydration operation, in the past, vacuum leaf filter was used for dehydration in front of metatitanic acid kiln, and the solid content (TiO2) after dehydration was only 30%~32%. Later, through the introduction of technology, the ancient filter was used for dehydration, and its solid content could reach 40%~45%. Now, almost all of China has used diaphragm filter press for dehydration, and its solid content can reach 50%~60%. The 30%~32% metatitanic acid dehydrated by the leaf filter consumes 603.104kj/ttio2 in the rotary kiln for calcination and dehydration, while the 50%~60% metatitanic acid dehydrated by the diaphragm filter press only consumes 242.8kj/ttio2, which is equivalent to saving 82.8kg of standard coal per ton of titanium dioxide, and the operating electricity cost is nearly 20% less than that of the ancient filter. As the moisture in metatitanic acid is greatly reduced, the production capacity of rotary kiln is significantly increased. In the past, one set φ The daily output of 2400 ~ 38000 rotary kilns is about 25t. After dehydration by diaphragm filter press, the output can be increased to 35t/d

in terms of dehydration before titanium dioxide post-treatment and drying, belt dryer and spray dryer were widely used in the past. Now almost all domestic pigment grade titanium dioxide has been changed to flash dryer, which is also inseparable from the high dehydration efficiency of diaphragm filter press. Some experts calculate that the energy consumption of the belt dryer is 1.0 higher, that of the spray dryer is 1.21, and that of the flash dryer is only 0.43. The energy saving effect is very obvious

5 roller mill replaces Raymond mill for crushing coarse products of kiln materials. Besides the advantages of small equipment, small vibration, light wear, small floor area and low maintenance cost, roller mill also has obvious energy-saving effect. One pm125r Raymond mill has an hourly output of 4~4.5t and an installed capacity of 280KW, while the installed capacity of roller mill with the same output is only 65kW, equivalent to 53.75kw power saving per ton of product, Converted into standard coal 6.5kg/ttio2

6 preheating recycling has also made remarkable achievements in the utilization of waste heat from flue gas of rotary kiln, when the oil delivery handwheel is closed, and in the recycling and reuse of cooling water. Especially in the recycling and reuse of water, various enterprises have done a lot of recycling and reuse work according to their own characteristics. At present, the water consumption (fresh water) of the domestic titanium dioxide industry is about 45~80t/t TiO2, which is compared with that in the 1980s, Almost halved

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