Saturday, April 13, 2024
Home xin Factors affecting the forming of vesicles in DPP-250 automatic blister machine

Factors affecting the forming of vesicles in DPP-250 automatic blister machine

by admin
0 comment

lignite drying technology 1. Reasons for moisture absorption of dry lignite there are many pores in lignite, and wet lignite is like a sponge that absorbs enough water; The dried lignite is like a sponge. When the dried lignite encounters water, it will absorb moisture, which is the same as that of the dried sponge. This is why the dried lignite will absorb moisture after being stored for too long or during transportation 2. Physical and chemical changes of lignite during drying. When lignite is heated to more than 100 degrees at room temperature, most of the free water can be evaporated. When the moisture content of lignite is lower than 15%, if it needs to continue drying and dehydration, that is, when removing the bound water, it needs higher temperature and energy because of the strong binding force between lignite and bound water. When lignite continues to be heated to more than 180 degrees under normal pressure, lignite bound water (internal water) can be removed. When the temperature of lignite is higher than 150 ℃, hydroxyl functional groups (mainly – COOH) decompose and release CO2 gas. At the same time, the bound water (internal water) of lignite is excluded. Further increasing the temperature will lead to the decomposition of more and more hydroxyl functional groups, resulting in the change of surface properties of lignite. At this drying temperature, due to the decomposition of a large number of hydroxyl functional groups, the pores in lignite collapsed and crosslinked. The collapse of pores can prevent water from entering pores; The cross-linking reaction can seal the pores and prevent the collapsed pores from re expanding when absorbing water. In addition, when the temperature of lignite is heated to more than 200 ℃, its surface area will be greatly reduced. The main reason for the reduction of surface area is the strong migration of tar in lignite under high-temperature drying conditions, that is, tar migrates from the inside of pores to the outside of pores. During the cooling process of tar transferred to the outside of the pores, the pores are sealed due to tar condensation, so the surface area of lignite is reduced. Due to the above process, i.e. the collapse of pores, the sealing of pores by crosslinking reaction and tar migration, lignite becomes more and more hydrophobic. At the same time, the hardening of lignite can be observed, which also leads to the formation of rigid structure of lignite. As a result, lignite can be converted from soft coal to hard coal and from hydrophilicity to hydrophobicity, so that long-distance transportation of lignite can be realized. 3. Size distribution of pores in dry lignite A. size distribution of pores in dry lignite the size distribution of pores in dry lignite is determined by mercury injection method. The pore size of lignite before drying is less than 0.01 & amp; micro; m. After drying, the pore size of lignite expands to 1.0-0.01 & amp; micro; M (and the kinetic radius of water molecules in steam is about 28 × 10-4& micro; m). B. the experimental results of porosity change of dried lignite show that the porosity of lignite before drying is 0.65cm3/g and that of lignite after drying is 0.3cm3/g. C. change of dry lignite surface area the surface area of dry lignite is determined by CO2 absorption method, and the surface area of lignite is 280m2 /g; Under the condition of medium temperature drying, the surface area of lignite is 223 m2 /g; Under the condition of high temperature, the surface area of lignite is 180 m2 /g. the main reason for the change of its surface area is the strong migration of tar in lignite under the condition of high temperature drying, that is, tar migrates from the inside of pores to the outside of pores. During the cooling process of tar transferred to the outside of the pores, the pores are sealed due to tar condensation, so the surface area of lignite is reduced. D. precipitation of chemical composition when the lignite temperature exceeds 200 ℃, tar is precipitated from the dry tail gas. When the temperature of lignite exceeds 150 ℃, CO2 is precipitated from the dry tail gas. The decomposition of carbonylates in lignite can reduce the hydrophilicity of lignite. In addition, the formation of CO2 in lignite also plays an important role in the removal of water in the gross pore structure and the migration of tar in lignite. The gas produced by the decomposition of hydroxyl functional groups (mainly – COOH). According to the composition analysis of lignite drying tail gas, the components of the gas produced by the decomposition of hydroxyl functional groups are as follows: c7h8, C5H10O, C7H8O, c9h12, c6h6o, C7H8O, c8h10o, C8H10O2, c9h10o, c9h10o2, C9H10O3, c6h6o2, C8H10O2, c9h12o2, C10H14O, C8H10O2, C10H12O2, C10H8, c10h10, c15h15, c15h18, c15h22, c46-62h92-104o2 4. Determination of lignite drying process parameters according to the above experimental research, different lignite drying process conditions can be determined according to different uses of dried lignite. A. for the case that only free water (external water) needs to be removed, for the pit mouth power station, lignite only needs to remove free water. Multi effect superheated steam drying process, the drying temperature shall not exceed 150 ℃. Otherwise, non condensable gas will be generated, which will affect the reuse of the generated steam (mainly reducing the heat transfer coefficient of the built-in heat exchanger of the dryer). For lignite drying process with flue gas as drying medium, the drying temperature shall not exceed 150 ℃. Otherwise, there will be combustible gas, fire or even explosion. Therefore, for the lignite drying process using flue gas as the drying medium, the drying temperature must be strictly controlled to avoid lignite overtemperature or even local overtemperature. Therefore, the lignite drying process using flue gas as the drying medium can only remove the free water (external water) of lignite. Even so, because it is difficult to avoid local overheating of lignite, the drying system will catch fire and explode. B. removal of bound water (internal water), i.e. lignite modification. Due to the removal of bound water (internal water), i.e. lignite modification, lignite needs to reach a higher temperature in order to remove bound water (internal water); At the same time, it is necessary to decompose the hydroxyl functional groups in lignite, collapse the pores and produce cross-linking, transfer the tar in lignite and seal the pores. Under this dry condition, combustible gas will be released. For the sake of safety, the drying system should preferably operate without oxygen or low oxygen, while superheated steam drying is the safest choice. 5. Test results · the vertical lignite dryer can be used for coal moisture control and lignite drying modification; · the drying process is safe without any danger of fire or explosion; · the total moisture of lignite can be reduced to less than 5%; · cracks appear after large lignite is dried; · tar is precipitated on the surface and inside of partially dried lignite, with bright color, which is similar to bituminous coal; · the partially dried lignite is soaked in water. After drying in the shade, the moisture is about 10%. 6. Problems existing in the existing lignite drying process · easy to explode – there are explosion problems for the drying process in which flue gas is in direct contact with coal; · serious wear – for the drying process with internal heating device and air flow drying process, there are equipment wear problems; · low capacity – for lignite drying and quality improvement, due to its high moisture content, the existing drying processes have the problem of low single machine capacity; 7. Advantages of lignite drying process · there is no possibility of explosion – due to the use of condensing superheated steam drying process that is not in direct contact with coal, the problem of explosion is completely eliminated. · slight wear – due to the very slow movement rate of the dried coal in the dryer, the wear problem is the lightest o
f all drying devices. · large single machine capacity – simple system and short process. By adjusting the structure and arrangement of heat exchange elements in the dryer, large particles of coal can be dried directly. Before drying, only coarse powder and screening are required, and granulation is not required after drying. · low operating cost – low system voltage drop and low power consumption. · one machine for multiple purposes – the final moisture of the product is easy to adjust. For lignite drying, only surface water can be removed, or surface water and combined water can be removed at the same time according to the demand. After drying, the modified lignite changes from hydrophilicity to hydrophobicity, and the calorific value can reach 5500-6000kcal /kg, which can realize long-distance transportation. 8. Brief introduction to lignite drying process. After lignite upgrading and drying, certain organic binder is added and processed, stirred, digested and pressed into lignite briquette products. It has the advantages of simple operation, convenient use and is suitable for the wide application of lignite drying, upgrading and molding with a large-scale annual output of 5-10 million tons. 9. Ly-ws-360 full-automatic hydraulic lignite forming machine ly-ws-360 full-automatic hydraulic lignite forming machine is a high-tech lignite forming machine with a pressure of 360 tons. It can press and form 12 pieces of lignite each time, and the annual output is more than 25 million pieces. The product has the advantages of low investment and quick effect, and is suitable for large-scale lignite extraction, drying and molding. 10. Main technical parameters (1) nominal pressing force: 360 tons (2) number of forming blocks: 12 blocks /time (3) forming cycle: 10 seconds (4) driving power: 55kW (main machine power) (5) overall dimension of main machine: 700mm × 2025mm × 4050mm 11. Application field · lignite drying and upgrading · coal humidity control (CMC) · slime drying

You may also like

Leave a Comment

Soledad is the Best Newspaper and Magazine WordPress Theme with tons of options and demos ready to import. This theme is perfect for blogs and excellent for online stores, news, magazine or review sites.

Buy Soledad now!

Edtior's Picks

Latest Articles

u00a92022u00a0Soledad.u00a0All Right Reserved. Designed and Developed byu00a0Penci Design.