干燥設(shè)備
干燥設(shè)備又稱干燥器和干燥機(jī)。用于進(jìn)行干燥操作的設(shè)備,通過加熱使物料中的濕分(一般指水分或其他可揮發(fā)性液體成分)汽化逸出,以獲得規(guī)定含濕量的固體物料。干燥的目的是為了物料使用或進(jìn)一步加工的需要。如木材在制作木模、木器前的干燥可以防止制品變形,陶瓷坯料在煅燒前的干燥可以防止成品龜裂。另外干燥后的物料也便于運(yùn)輸和貯存,如將收獲的糧食干燥到一定濕含量以下,以防霉變。由于自然干燥遠(yuǎn)不能滿足生產(chǎn)發(fā)展的需要,各種機(jī)械化干燥器越來越廣泛地得到應(yīng)用。
去濕的方法按作用原理可以分為機(jī)械法、熱物理法和物理化學(xué)法三種。一般情況下熱物理法去濕稱為干燥, 干燥就是利用熱能使?jié)裎锪现械臐穹?(水分或其他溶劑) 汽化, 水汽或蒸汽經(jīng)氣流帶走或由真空泵將其抽出除去, 而獲得固體產(chǎn)品的操作過程。對濕物料進(jìn)行干燥時(shí), 有兩種干燥過程, 一種是表面汽化過程, 熱量從周圍環(huán)境傳遞至物料表面, 使表面濕分蒸發(fā)另一種是內(nèi)部擴(kuò)散控制過程, 物料內(nèi)部濕分傳遞到物料表面, 然后再蒸發(fā)。物料的干燥速率由上述兩個(gè)過程中速率較慢的一個(gè)控制。
通過物料干燥特性試驗(yàn)可知, 物料干燥過程可以分為三個(gè)階段。第一階段為物料預(yù)熱階段, 在此期間主要是對濕物料進(jìn)行預(yù)熱, 同時(shí)也有少量濕分汽化, 物料的溫度很快升到近似等于濕球溫度;第二階段為恒速干燥階段, 此階段主要特征是熱空氣傳給物料的熱量全部用來汽化濕分, 物料表面溫度一直保持不變, 濕分則按一定速率汽化;第三階段為降速干燥階段, 此時(shí)物料的干燥速率由內(nèi)部擴(kuò)散過程控制, 熱空氣所提供的熱量只有一小部分用來汽化濕分, 而大部分則用來加熱物料, 使物料表面溫度上升, 但是干燥速率則逐步降低, 直至達(dá)到平衡含濕量為止。
隨著工農(nóng)業(yè)的迅猛發(fā)展, 干燥設(shè)備工業(yè)正不斷成熟和壯大, 成為機(jī)械工業(yè)中一個(gè)具有蓬勃生機(jī)的新興行業(yè)。需進(jìn)行干燥的既有數(shù)千萬噸的大批量物料, 也有年產(chǎn)僅幾十公斤的貴重物品;因而既有一些大型干燥設(shè)備以適應(yīng)獨(dú)特的工藝要求和生產(chǎn)能力, 又有一些中小型通用干燥設(shè)備。干燥設(shè)備廣泛應(yīng)用于化工、建材、食品、藥物及生化等行業(yè)。
干燥設(shè)備分類:
干燥設(shè)備的種類繁多, 根據(jù)操作壓力、操作方式、傳熱原理、加熱方式、構(gòu)造等的不同可以將干燥設(shè)備歸于不同的類別。按操作壓力可以分為常壓式和真空式兩類;按操作方式可分為間歇操作和連續(xù)操作兩類;按傳熱原理可分為傳導(dǎo)加熱式、對流加熱式、輻射傳熱式和高頻加熱式等幾類;按加熱方式可分為直接加熱式和間接加熱式兩類;按構(gòu)造可以分為噴霧干燥器、流化床干燥器、氣流干燥器、槳式干燥器、箱式干燥器及旋轉(zhuǎn)閃蒸干燥器等。
干燥設(shè)備應(yīng)用行業(yè):
石油及化學(xué)工業(yè):聚合、縮合、蒸餾、熔融、脫水、強(qiáng)制保溫。
油脂工業(yè):脂肪酸蒸餾、油脂分解、濃縮、酯化、真空脫臭。
合成纖維工業(yè):聚合、熔融、紡絲、延伸、干燥。
紡織印染工作:熱定型、烘干、熱容染色。
非織造工業(yè):無紡布。
飼料工業(yè):烘干。
塑料及橡膠工業(yè):熱壓、壓延、擠壓、硫化成型。
造紙工業(yè):干燥、波紋紙加工。
木材工業(yè):多合板、纖維板加壓成型、木材干燥。
建材工作:石膏板烘干、瀝青加熱、混凝土構(gòu)件養(yǎng)護(hù)。
機(jī)械工業(yè):噴漆、印花烘干。
食品工業(yè):烘烤、加熱。
空調(diào)工業(yè):工業(yè)廠房及民用建筑采暖。
筑路工業(yè):瀝青熔化、保溫。
制藥工業(yè):烘干。
輕工業(yè):生產(chǎn)油墨、洗衣粉。
Drying equipment is also known as dryers and dryers. A device for performing a drying operation by vaporizing a moisture component (generally referred to as moisture or other volatile liquid component) in a material to obtain a solid material having a prescribed moisture content. The purpose of drying is for the purpose of material use or further processing. For example, the drying of the wood before the production of the wood mold and the wood can prevent the deformation of the product, and the drying of the ceramic material before the calcination can prevent the product from cracking. In addition, the dried material is also convenient for transportation and storage, such as drying the harvested food to a certain moisture content to prevent mildew. Since natural drying is far from meeting the needs of production development, various mechanized dryers are becoming more and more widely used.
The method of dehumidification can be divided into mechanical method, thermophysical method and physical chemistry method according to the principle of action. In general, thermophysical dehumidification is called drying. Drying is the use of heat to vaporize moisture (moisture or other solvent) in wet materials. Water vapor or steam is taken away by airflow or removed by a vacuum pump to obtain a solid product. Operation process. When drying wet materials, there are two drying processes, one is surface vaporization process, heat is transferred from the surrounding environment to the surface of the material, so that the surface moisture is evaporated. The other is internal diffusion control process, and the internal moisture content of the material is transferred to the material. Surface, then evaporate. The drying rate of the material is controlled by one of the slower rates in the two processes described above.
The material drying process can be divided into three stages by the material drying characteristic test. The first stage is the material preheating stage. During this period, the wet material is preheated, and a small amount of moisture is vaporized. The temperature of the material quickly rises to approximately equal to the wet bulb temperature; the second stage is the constant speed drying stage. The main feature of this stage is that the heat transferred from the hot air to the material is used to vaporize the moisture, the surface temperature of the material remains unchanged, and the moisture is vaporized at a certain rate; the third stage is the slow drying stage, at which time the drying rate of the material Controlled by the internal diffusion process, only a small portion of the heat supplied by the hot air is used to vaporize the moisture, while most of it is used to heat the material, causing the surface temperature of the material to rise, but the drying rate is gradually reduced until the equilibrium moisture content is reached. until.
With the rapid development of industry and agriculture, the drying equipment industry is constantly maturing and expanding, becoming an emerging industry in the machinery industry with vitality. There are tens of millions of tons of large-volume materials that need to be dried, as well as valuables with an annual output of only a few tens of kilograms; therefore, there are some large-scale drying equipment to adapt to unique process requirements and production capacity, and some small and medium-sized general drying. device. Drying equipment is widely used in chemical, building materials, food, pharmaceutical and biochemical industries.
Drying equipment classification:
There are many types of drying equipment, and the drying equipment can be classified into different categories depending on the operating pressure, operation mode, heat transfer principle, heating method, structure, and the like. According to the operating pressure, it can be divided into two types: atmospheric pressure type and vacuum type; according to the operation mode, it can be divided into two types: intermittent operation and continuous operation; according to the heat transfer principle, it can be divided into conduction heating type, convection heating type, radiation heat transfer type and high. Frequency heating type, etc.; according to the heating method can be divided into direct heating type and indirect heating type; according to the structure can be divided into spray dryer, fluidized bed dryer, airflow dryer, paddle dryer, box drying And rotary flash dryers, etc.
Drying equipment application industry:
Petroleum and chemical industries: polymerization, condensation, distillation, melting, dehydration, forced insulation.
Oil industry: fatty acid distillation, oil decomposition, concentration, esterification, vacuum deodorization.
Synthetic fiber industry: polymerization, melting, spinning, stretching, drying.
Textile printing and dyeing work: heat setting, drying, heat capacity dyeing.
Non-woven industry: non-woven fabrics.
Feed industry: drying.
Plastics and rubber industry: hot pressing, calendering, extrusion, vulcanization molding.
Paper industry: Dry, corrugated paper processing.
Wood industry: plywood, fiberboard compression molding, wood drying.
Building materials work: gypsum board drying, asphalt heating, concrete component maintenance.
Machinery industry: painting, printing and drying.
Food industry: baking, heating.
Air-conditioning industry: industrial plants and civil buildings for heating.
Road construction industry: asphalt melting, insulation.
Pharmaceutical industry: drying.
Light industry: production of ink, washing powder.
在干燥設(shè)備中多使用蒸汽來作為干燥源,閥門多采用來控制蒸汽的流量、壓力和溫度的閥門,如 電動(dòng)單座調(diào)節(jié)閥,電動(dòng)套筒調(diào)節(jié)閥,電動(dòng)三通調(diào)節(jié)閥,氣動(dòng)單座調(diào)節(jié)閥,氣動(dòng)套筒調(diào)節(jié)閥,氣動(dòng)三通調(diào)節(jié)閥,手動(dòng)調(diào)節(jié)閥,法蘭閘閥,法蘭截止閥,過濾器,安全閥等閥門設(shè)備
??????????????? Steam is used as a drying source in drying equipment. Valves are used to control the flow, pressure and temperature of steam, such as electric single seat control valve, electric sleeve control valve, electric three-way control valve, pneumatic single seat adjustment. Valve, pneumatic sleeve regulating valve, pneumatic three-way regulating valve, manual regulating valve, flange gate valve, flange stop valve, filter, safety valve and other valve equipment ???????????????