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关于轴径问题? 先确定负荷,然后再说别的 查看更多
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硝酸生产中气氨过滤器需要备台设备吗? 如果在运行过程中出现有堵塞、压差大的现象怎么办?可以单独切换出来吗?查看更多
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请问GB150与JB4732的区别? 我没有查看详细内容,至少gb是国标,而jb是机械标准。查看更多
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熟悉加热炉的大大们请进来下 小弟有问题请教? lz 清楚了吗? 就是从这公式算出来的。查看更多
注化考试基础部分复习经验? 谢谢lz分享,受教了,备考的注化基础的飘过~~查看更多
离子膜电解槽知识? 电解槽-正文 进行电解反应的装置(见彩图)。电解槽由槽体、阳极和阴极组成,多数用隔膜将阳极室和阴极室隔开。按电解液的不同分为水溶液电解槽、熔融盐电解槽和非水溶液电解槽三类。当直流电通过电解槽时,在阳极与溶液界面处发生氧化反应,在阴极与溶液界面处发生还原反应,以制取所需产品。对电解槽结构进行优化设计,合理选择电极和隔膜材料,是提高电流效率、降低槽电压、节省能耗的关键。   电解槽结构  采用不同的电解液时,电解槽的结构也有所不同。   水溶液电解槽  分有隔膜和无隔膜两类。一般多用隔膜电解槽。在氯酸盐生产和水银法生产氯气和烧碱时,采用无隔膜电解槽。尽量增大单位体积内的电极表面积,可以提高电解槽的生产强度。因此,现代隔膜电解槽中的电极多为直立式。电解槽因内部部件材质、结构、安装等不同表现出不同的性能与特点。   例如按电极的连接方式,可分为单极式和复极式两类电解槽(见图)。单极式电解槽中同极性的电极与直流电源并联连接,电极两面的极性相同,即同时为阳极或同时为阴极。复极式电解槽两端的电极分别与直流电源的正负极相连,成为阳极或阴极。电流通过串联的电极流过电解槽时,中间各电极的一面为阳极,另一面为阴极,因此具有双极性。当电极总面积相同时,复极式电解槽的电流较小,电压较高,所需直流电源的投资比单极式者省。复极式一般采用压滤机结构形式,比较紧凑。但易漏电和短路,槽结构和操作管理比单极式复杂。单极式电解槽截面一般为长方形或方形,圆筒形占地大,空间利用率低,采用较少。   阴、阳两极间距是影响槽电压的重要因素之一。随极间距增大,槽内欧姆电压降增大,槽电压升高。尤其是在大电流工作时,这种电压损失更为严重。现代电解槽采用各种措施以降低极间距,如采用扩散阳极、改性隔膜制成零极距电解槽结构等。   电解液在电解槽内的停留时间,不仅影响设备的生产能力,而且在某些情况下,会影响电解过程的电流效率,如电解法制氯酸钠,由于中间产物次氯酸(hclo)和次氯酸根离子(clo3)间的化学反应速度非常缓慢,如长时间留在电解槽内,不仅降低电解槽利用率,而且次氯酸根离子会在阳极表面氧化,或在阴极表面还原,降低电流效率。因此,现代电解槽设计力求减小容积,使电解液沿着电极快速流过。如还需进一步进行反应,则可在电解槽外安装独立的化学反应器。   电解槽内电极以垂直安装较紧凑,导电板连接容易,并利于降低气泡效应。因在有气体析出的电极表面上常附有气泡,会降低电极的工作表面积。另外,在电极附近的溶液中也会充有气泡,增大溶液电阻,这种现象称“气泡效应”。但在垂直电极表面的附近,则可利用溶液中充气度高、溶液密度低与上升速度快的特点,以形成电解液的自然循环,使气泡加速离开电极表面,减轻气泡效应。当垂直电极用作气体电极时,电极形状以网状为多,它除了能增加工作表面积外,也有利于气泡逸出。   电解槽材料可以是钢材、水泥、陶瓷等。钢材耐碱,是应用最广的。对于腐蚀性强的电解液,钢槽内部用铅、合成树脂或橡胶等衬里。   目前电解槽正朝大容量、低能耗方向发展。复极式电解槽适于大型生产,先后为电解水和氯碱工业所采用。   熔融盐电解槽  多用于制取低熔点金属,其特点是在高温下运转,并应尽量防止水分进入,避免氢离子在阴极上还原。例如制取金属钠时,由于钠离子的阴极还原电位很负,还原很困难,必须用不含氢离子的无水熔融盐或熔融的氢氧化物,以免阴极析出氢。为此电解过程需在高温下进行,例如电解熔融氢氧化钠时为 310℃,如其中含有氯化钠成为混合电解质时,电解温度为650℃左右。电解槽的高温可以通过改变电极间距,将欧姆电压降所消耗的电能转变为热能来达到。电解熔融氢氧化钠时,槽体可用铁或镍,电解含有氯化物的熔融电解质时常由于原料中不可避免地带入少量水分,会使阳极生成潮湿的氯气,对电解槽的腐蚀作用很强,因此电解熔融氯化物的电解槽,一般用陶瓷或磷酸盐材料,而不受氯气作用的部位可用铁。熔融盐电解槽中的阴、阳极产物,同样要求妥善隔开,而且应尽快由槽中引出,以免阴极产物金属钠长时间飘浮在电解液表面,会进一步与阳极产物或空气中的氧起作用。   非水溶液电解槽  由于非水溶液电解槽在制取有机产品或电解有机物时,常伴随有各种复杂的化学反应,使其应用受到限制,工业化的不多。一般采用的有机电解液,电导率低,反应速度也小。因此,必须采用较低的电流密度,极间距尽量缩小。采用固定床或流化床的电极结构有较大的电极表面积,可提高电解槽生产能力。   电极  阳极和阴极的作用不同,对材质要求也各异。   阳极  分可溶性和不可溶性两类。在精炼铜用的电解槽中,阳极材料为可溶性的待精炼的粗铜。它在电解过程中溶入溶液,以补充在阴极上从溶液中析出的铜。在电解水溶液(如食盐水溶液)用的电解槽中,阳极为不溶性的,它们在电解过程基本不发生变化,但对在电极表面上所进行的阳极反应常具有催化作用。在化学工业中,大多采用不溶性阳极。   阳极材料除需满足一般电极材料的基本需求(如导电性、催化活性强度、加工、来源、价格)外,还需能在强阳极极化和较高温度的阳极液中不溶解、不钝化,具有很高的稳定性。长期以来,石墨是使用最广泛的阳极材料。但石墨多孔,机械强度差,且容易氧化成二氧化碳,在电解过程中不断地被腐蚀剥落,使电极间距逐渐增大,槽电压升高。用于电解食盐水溶液时,石墨电极上的析氯过电位也较高。   60年代h.比尔提出的在钛基上涂覆氧化钌、氧化钛而形成的金属氧化物电极是阳极材料的一个重大革新。二氧化钌对某些阳极反应如析氯、析氧具有很好的催化活性,能在高电流密度下工作而槽电压比较低。最突出特点是具有很好的化学稳定性,工作寿命比石墨阳极长得多。例如在氯碱生产用的隔膜电解槽中,其寿命可达10年以上。由于它不易腐蚀,尺寸稳定,被称为形稳性阳极。为适应不同要求和用途,可在涂层中添加其他组分,如加入锡、铱可提高氧的过电位,改善阳极的选择性,又如加入铂可提高电极的稳定性等。目前,贵金属涂层的金属阳极在化学工业中已得到普遍推广。   在熔融盐电解槽中,因电解温度比水溶液电解槽中高得多,对阳极材料要求更严,电解熔融氢氧化钠,一般可用钢铁、镍及其合金。电解熔融氯化物,只能用石墨。   阴极  以金属或合金作为阴极时,由于在比较负的电位下工作,往往可以起到阴极保护作用,腐蚀性小,所以阴极材料比较容易选择。在水溶液电解槽中,阴极一般产生析氢反应,过电位较高。因此阴极材料的主要改进方向是降低析氢过电位。除用硫酸作为电解液时必须采用铅或石墨作阴极外,低碳钢是常用的阴极材料。为降低电耗,目前采用各种方法制备高比表面积,并具有催化活性的阴极,如多孔镍镀层阴极。   为了提高产品质量,也可采用特殊的阴极材料,如在水银法电解食盐水溶液制取烧碱的汞阴极中,利用汞析氢过电位高的特点,使钠离子放电,生成钠汞齐,然后在专用的设备中,用水分解钠汞齐制取高纯度、高浓度碱液。另外,为了节约电能也可采用耗氧阴极,使氧在阴极还原,以代替析氢反应,按理论计算可降低槽电压1.23v。   隔膜  为防止阴、阳两极产物混合,避免可能发生的有害反应,在电解槽中,基本上都用隔膜将阴、阳极室隔开。隔膜需有一定的孔隙率,能使离子通过,而不使分子或气泡通过,当有电流流过时,隔膜的欧姆电压降要低。这些性能要求在使用过程中基本不变,并且要求在阴、阳极室电解液的作用下,有良好的化学稳定性和机械强度。电解水时,阴、阳极室的电解液相同,电解槽的隔膜只需将阴、阳极室隔开,以保证氢、氧纯度,并防止氢氧混合发生爆炸。更多见的比较复杂的情况是电解槽中阴、阳极室的电解液组成不同。这时隔膜还需要阻止阴、阳极室电解液中电解产物的相互扩散和作用,如氯碱生产中隔膜法电解槽中的隔膜,可以增大阴极室氢氧离子向阳极室扩散和迁移的阻力。   隔膜由惰性材料制作,如氯碱工业中长期使用的石棉隔膜。但石棉隔膜性能不稳定,当盐水中含有钙、镁杂质时,容易在隔膜中生成氢氧化物沉淀,降低透过率;在比较高的温度和在电解液作用下,还会发生膨胀、松脱。为此可以在石棉中加入树脂作为增强材料,或以树脂为主体做成微孔隔膜,在稳定性和机械强度方面都有很大改进。近年来氯碱生产开发的阳离子交换膜是新型的隔膜材料。它具有对离子透过的选择性,可使氯离子基本上不进入阴极室,从而可以制得氯化钠含量极低的碱液。查看更多
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福斯Logix 400 Series定位器操作手册? 来人那 查看更多
工程技术人员年薪? 我们都没有奖金的 月薪1500 哎查看更多
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求助有关腈水解? 盐酸恐怕不行,一般可能要60%左右的硫酸,温度也比较高。查看更多
关于翼阀的开口朝向,是朝向设备中心,还是朝向器壁,还 ...? 我们再生器里的翼阀朝向圆周切线方向的 查看更多
化工及化工设备软件,很好用!? 用了一段时间,大概一个月,突然就不能用了,不知为什么查看更多
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请教加氢的问题? 但是有选择性的问题,这样的条件选择性会比较差。查看更多
氯碱淡盐水浓缩热泵技术工艺? 大哥,帮忙设计一套成不? 你是真的假的??? 我以前在的厂子老板 就自己做了套热泵蒸馏设备。 就是缺很多自动控制的东西。 就是那个泵贵点18万左右。 小型的应该能做 查看更多
关于防爆电机的疑问? 电梯厂家是做了的。 关键看批量,效益。 查看更多
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哪位有 2017年制作全面落实企业安全生产主体责任 PPT课 ...? 你好,类似这样的 落实企业主体责任的课件 ,谢谢啦http:///it/d20170515/140677604_678726. ... 没有呀! 查看更多
好的英语是“读”出来的? 改变人生的100个方法(10) 91. inflate your goal. **** this self motivator can be used as an intellectual tool. take a certain goal of yourself and double it or triple it or multiple it by ten. and then ask yourself quite seriously what would you have to do to achieve that new goal. remember, this is just a self contained game and not a promise to anyone else. but it is a game that's fun to play. why? because it works. 92. come to your own rescue. **** 1. you can't leave a place you never been. 2. no one is coming. i use to believe i can run from all my freighting thoughts and beliefs about myself. but all that ever did was create deeper internal fears and conflicts. what i needed to do was to get all my fears into the sunshine and demystify them. once i systematically was able to do that, i was able to dismantle the fears like bomb squid does to a bomb. acceptance and full conscious of those fears was the place i've never been. once i was in that place, i could leave. the notion that no one is coming is more terrifying. you can much happier if you value independence and self-reliancy then depending on someone else. so when you accept the idea that no one is coming, it's actually that very powerful moment. it means you accepted that you are enough. you can actually handle problems yourself. you can grow. you can get strong. you can generate your own happiness. and paradoxically, from that position of independence truly great relationships can be built because they are not based on dependency. they are not based on fear. they are based on mutual independence and love. see how much better you are at self motivation once you begin to celebrate the news that you are enough. 93. push your own buttons. motivation never has to be accidental. any form of motivation. a lot of people like to motivate themselves musically for example. but you don't have to wait for hours until a certain song comes on the radio that picks up your spirits. you can control what songs you hear. if there are certain songs that lifts you up, create a greatest hits motivation tape for yourself. you got much more control over your environment than you ever realized. learn how to push your own buttons. 94. strengthen your rehearsal. the harder you are on yourself, the easier life is on you. there isn't anything that life can challenge you with that you can't challenge yourself with ahead of time. you can set yourself up to succeed. if you have to make a presentation in front of someone that scares you, you can always rehearse it in front of someone that scares you even more. if you got something hard to do and your hesitant to do it, find something even harder and do that first. watch what it does to your self-motivation going into the real challenge. 95. improve your vision. * "it's not what a vision is, it's what a vision does." so what does your vision do to you? does it give you energy? does it make your smile? when your tired, does it give you energy to go that extra mile? a vision should be judged by these criteria. the criteria of power and effectiveness. in other words, what does it do? what do you want to bring into being. if your vision isn't giving you energy then picture another one. keep at it until you develop a vision that is so colorful and so clear it puts you in action just to think about it. 96. build your power base. * the more awake you are, the more conscious you are, and the more you pay attention to how your own efforts at self-motivation are succeeding, the more powerful you'll become. your knowledge of self-motivation is power in it of itself. respect your knowledge and build on it. 97. link truth to beauty. **** the best case for honesty is how beautiful it is. how clean it clear it makes the journey from current reality to the dream. truth leads you to a more confident level in your relationships with others and with yourself. it diminishes fear and it increases your sense of personal mastery. lies, half-truths, will always weigh you down. where as truth will clear up your thinking and give you the energy and clarity needed for self motivation. 98. take no for a question. **** ask the universe for what you want. don't take no for an answer. take no for a question. when you ask for something that is denied to you, imagine that the no you heard is really the question, "can't you be more creative than that?" never accept no at face value. let rejection motivate you to get more creative. 99. walk with love and death. **** whenever i need to get through something, create something or face some kind of courageous plan, i always take long walks. when i walk long and far enough a solution always appears. i eventually get oriented to the most creative action. andrew wiles in "spontaneous healing" says when you walk, the movements of your limbs are cross patterned. the right leg and left arm move forward at the same time and the left leg and right arm. the spontaneous type of movement generates electrical activity in the brain that has a harmonizing influence on the central nervous system. a special benefit of walking that you don't necessary get from other type of exercise. i call it "a walk with love." because love and fear are opposites. most people think love and hate are opposites but their not. the ultimate creativity occurs from the spirit of love. love is always creative and fear is always destructive. and i called it a "a walk with death" because it is only the acceptance and awareness of my own death that give my life the clarity it needs to make my life exciting. take your own challenges out for a walk. feel your own self-motivation growing inside of you. feel the electricity in your brain. feel it harmonize with your central nervous system. you'll soon know for a fact that you do have what it takes. you can walk courage into existence. 100. buy yourself flowers. buy yourself flowers and every time you look at them, let them remind you of how colorful your future is going to be. how fresh your thoughts are. how easy it is to honor yourself. how much power you have to make your environment beautiful. and how sweet the smell of the universe can be.查看更多
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制氢催化剂? https:///thread-1282585-2-1.html ,看看这套技术问答,对你有所帮助查看更多
延迟焦化产出的石脑油可否作为重整原料? 我们装置的直接进重整,可以做原料查看更多
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反应动力学参数的查询? 期待中 哪位高人有类似的资料啊查看更多
求助前辈在煤制氢项目中哪个单元能学到最多的东西? 想什么呢?当然是气化了!气化现在有专利,搞清楚了各种气化方法,煤气化就搞定了!变换是小单元,催化剂已经基本稳定,主要是换热;甲醇洗不过是新的净化方法而已,个人不看好;甲烷化和变换差不多查看更多
简介
职业:江西贝美药业有限公司 - DMC、PC操作工
学校:湖南城市学院 - 化学与环境工程系
地区:黑龙江省
个人简介:真实是人生的命脉,是一切价值的根基。查看更多
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