Name: ammonia synthesis at low pressure
Uploaded: 2017-08-23T13:00:00
Description: Watch this Scientific Journal Video about Ammonia Synthesis at Low Pressure at JoVE.com

这项工作主要由 ARPA-E，美国能源部明尼苏达州环境和天然资源信托基金，部分建议立法公民委员会对明尼苏达州资源和 MNDRIVE 的一项倡议明尼苏达大学。额外支持来自德雷福斯基金会。

1.飞行员厂启动 <ol><li>氮生产系统 <ol><li>转上空气干燥机、 空气压缩机、 氮发生器。验证至少 800 kPa 的空气压缩机储气罐。这不断发送氮到缓冲罐，直至不超过 0.004%(40 ppm) 氧氮。</li>
		<li>开启氮气气体增压器。气体增压器开始填充氮气供应坦克，在压力下高达 17 MPa。</li>
	</ol></li> <li>制氢系统 <ol><li>打开冷水机组、 水去离子装置和电解槽。电解槽将无法运行没有排气?...

<ol>
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M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinetic+Expression+with+Diffusion+Correction+for+Ammonia+Synthesis+on+Industrial+Catalyst.">Kinetic Expression with Diffusion Correction for Ammonia Synthesis on Industrial Catalyst.</a> Ind Eng Chem Fund. 7 (4), 605-610 (1968).</li><li>Temkin, M., Pyzhev, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinetics+of+ammonia+synthesis+on+promoted+catalysts.">Kinetics of ammonia synthesis on promoted catalysts.</a> Acta Physiochim USSR. 12, 327-356 (1940).</li><li>Annable, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+the+Temkin+kinetic+equation+to+ammonia+synthesis+in+large-scale+reactors.">Application of the Temkin kinetic equation to ammonia synthesis in large-scale reactors.</a> Chem Eng Sci. 1 (4), 145-154 (1952).</li><li>Guacci, U., Traina, F., Ferraris, G. B., Barisone, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+Application+of+the+Temkin+Equation+in+the+Evaluation+of+Catalysts+for+the+Ammonia+Synthesis.">On the Application of the Temkin Equation in the Evaluation of Catalysts for the Ammonia Synthesis.</a> Ind Eng Chem Prod DD. 16 (2), 166-176 (1977).</li><li>Hummelsh&#248;j, J. S., S&#248;rensen, R. Z., Kustova, M. Y., Johannessen, T., N&#248;rskov, J. K., Christensen, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+nanopores+during+desorption+of+NH3+from+Mg(NH3)6Cl2.">Generation of nanopores during desorption of NH3 from Mg(NH3)6Cl2.</a> J Am Chem Soc. 128 (1), 16-17 (2006).</li><li>Huberty, M. S., Wagner, A. L., McCormick, A., Cussler, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ammonia+absorption+at+haber+process+conditions.">Ammonia absorption at haber process conditions.</a> AIChE Journal. 58 (11), 3526-3532 (2012).</li><li>Himstedt, H. H., Huberty, M. S., McCormick, A. V., Schmidt, L. D., Cussler, E. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ammonia+synthesis+enhanced+by+magnesium+chloride+absorption.">Ammonia synthesis enhanced by magnesium chloride absorption.</a> AIChE Journal. 61 (4), 1364-1371 (2015).</li><li>Malmali, M., Wei, Y., McCormick, A., Cussler, E. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ammonia+Synthesis+at+Reduced+Pressure+via+Reactive+Separation.">Ammonia Synthesis at Reduced Pressure via Reactive Separation.</a> Ind Eng Chem Res. 55 (33), 8922-8932 (2016).</li><li>Wagner, K., Malmali, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Column+absorption+for+reproducible+cyclic+separation+in+small+scale+ammonia+synthesis.">Column absorption for reproducible cyclic separation in small scale ammonia synthesis.</a> AIChE Journal. , (2017).</li></ol>

反应吸收实验装置的关键步骤:
确保氮气和氢气系统中没有杂质。吸水材料在每次循环后都会发生变化。在大多数情况下, 在高温和氨的存在下, 吸水材料的保险丝和形成一个大的固体混凝土。根据每个金属卤化物和氨络合物的热力学性质, 应采用适当的吸收和解吸温度。在每次测试之前, 应检查系统的压降 (吸收器、反应器、油管、阀门、管件、等), 以确保回流回路、减震...

氨是一种重要的工业化学品。它是通过哈伯-博世工艺生产的, 它被称为 20th世纪12中最重要的创新之一。氨合成是在一个非均相催化剂的存在下进行的, 在高温 (#62; 375 ° c) 和压力 (和 #62; 100 bar)3。如此高的温度和压力要求使氨合成非常能量-和 capital-intensive。大约1.5亿吨氨每年生产4, 占世界能源消耗的 1-3%, 5% 的天然气消耗量, 以及多达3% 的气候变化气体排放量5,6, 7。
氨有两个主要的潜在用途。首先, 氨是一种合成氮肥1。如果没有这种肥料, 目前人口的一半将无法获得足够的粮食。其次, 氨水可以作为一种能量载体, 或者作为一种碳中性液体燃料或间接氢载体8,9,10,11。典型地, 可再生资源 (例如风) 在稀少农村地区是可利用的, 在那里可以被夺取;这种类型的孤立风和太阳能被称为 "搁浅"。在这种情况下, 可再生能源的电能和热能被转换成能量密集的碳中性液氨。所生产的液氨可以运往城市中心, 在那里可以直接用于氨基燃料电池12和内燃机的13, 也可以分解成氢气, 然后用于氢燃料电池或氢气站因此, 我们可以把美国大草原的风移到美国拥挤的城市地区。
主要是由于化肥的使用, 合成氨生产是一个重要的行业。在室温下, 氨合成反应是放热的, 因此-至少, 在原则上自发的14, 但是, 在环境条件下实现反应非常困难, 因为强氮氮键15. 为了克服这一点, 弗里茨哈伯著名地使用高温来达到快速的动力学, 但这些高温意味着反向反应抑制生产。为了减少这种反向反应的抑制作用, 哈伯使用高压来改善转换。他执行了 large-scale 反应在枪管, 仍然装饰 BASF 植物在路德维希港。
当反应可能在更温和的条件下运行时, 必须同时使用高温和压力, 这使化学家们沮丧了一个世纪2。即使在这个过程被商业化之后, 卡尔. 博世和巴斯夫的一个庞大的队伍在整个周期表中搅动着寻找更好的催化剂。尽管博世没有取得什么成功, 但搜索仍在继续。甚至在去年, 一个新的研究计划, 旨在寻求一个新的催化剂启动16,17。详细的氨合成化学现在已经很好的理解14, 如果寻找新的催化剂是成功的, 它肯定是值得的努力。然而, 我们认为, 过去的失败减少了未来成功的机会。
本文介绍了 small-scale 氨合成工艺, 并对其进行了研究。
小规模的过程:
风力发电氨 我们正在改进哈伯-博世合成氨的工艺, 寻求一个更小, 更简单的过程, 可以在当地运行, 但产生微不足道的二氧化碳量。在一个位于莫里斯, 锰的试验工厂已经证明了当地氨制造的可行性, 并显示在图 118。莫里斯坐在水牛脊, 在明尼苏达州西南角的六十英里的连绵起伏的山丘的形成。山脊有异常稳定, 强风, 横跨草原滚动。因此, 它是风力发电的圣地。
用这种电, 我们已经从风中生产氨, 使用的是比现有的化石燃料商业操作小4万倍的植物。一些风力发电是用来使空气中的氮气通过变压吸附, 一种既定的方法, 空气分离使用, 例如, 对于肺气肿患者需要富氧空气。然而, 更多的电力是用来制造氢气的电解水。在图 2中示意的过程中, 这些气体与常规催化剂结合在一起。反应后, 气体通过冷却分离, 浓缩液氨。未气体, 以及 uncondensed 氨, 被回收。
试验工厂详情 在我们的试验工厂, 明尼苏达大学的可再生氢和氨试验厂, 电力是由一个合用的1.65 兆瓦风力涡轮机提供。该试验工厂使用约10% 的功率产生, 剩余的电力使用的明尼苏达大学, 莫里斯校区。
氢气生产系统使用一个电解槽, 增压压缩机, 和一个热冷水机组。该系统每小时生产0.54 公斤氢气, 储存在 2400 psi, 使用24千瓦时电能。利用反渗透和离子系统纯化 on-site 井的水。然后, 水以高达15升/小时的速度供应给电解槽. 氮气是用氮气发生器、pre-air 压缩机、空气干燥器和增压压缩机产生的。氮气储存在 2400 psi, 使用约6千瓦小时的电力。
合成氨的合成使用定制的刹车。它包括一个压缩机, 一个反应堆, 一个制冷冷却回路, 和一个20千瓦的电加热器。该橇使用约28千瓦小时的电力生产2.7 公斤的氨水, 然后储存在 150 psi。采用集成 PLC 和 HMI 系统控制合成氨生产过程。生产的氢气和氮气储存在现场18氮斯道拉恩索ge 坦克和54储氢罐。氨水也在3100加仑的容器内存放在现场。
风力发电是昂贵的 这一过程的电是由风制成的, 因此制造氨水的燃料是免费的, 不需要使用任何化石燃料。然而, 这一试点工厂的资本成本主要是以氢气生产和合成氨的投资为主导。迄今为止的操作表明, 制造 small-scale 氨的成本大约是传统的基于化石燃料的氨水的两倍。虽然我们继续优化我们的过程, 我们相信, small-scale 风产生的氨将不会在目前的天然气价格竞争力。每块质量氨的资本成本可以通过一个更大的常规过程来减少, 或者通过一个类似于本文接下来所描述的替代过程来降低。
吸收过程:
吸收增强生产 用于合成氨的催化剂在上个世纪19几乎保持不变。因此, 我们在这项研究中采取了不同的方法。我们应用了当前的催化剂和操作温度, 但一旦形成, 就会在适度的压力下吸收氨水。我们回收任何未的氢和氮。该过程类似于图 3中的示意图, 与常规过程相似, 但用填充床吸收器代替了凝汽器。
初始反应动力学不改变 该系统的低转换实验表明, 初始反应速率与本系统早期的许多研究是一致的3,14,15,20,21,22,23, 如图 4所示。左面板显示初始速率, 随温度的变化强烈。虽然这些速率也随压力而变化, 但变化较小, 如右面板所示。在我们的新的过程中, 我们使用相同的催化剂和类似的操作条件, 但寻求方法, 以改善氨生产使用在较低的压力吸收。因此, 我们希望降低氨合成的资本成本。
吸收增强转换 在我们的工作中, 我们用填料床代替了小型的冷凝器, 这是一个充满了吸收剂的小颗粒的圆柱形容器。我们强调了主要由氯化镁和氯化钙制成的吸附剂11,24。这种氨吸收剂有两种作用。首先, 它们将回收气体中的氨浓度降低到接近零。第二, 他们有效地减少了分离的时间到接近零。此策略具有生产性25、26、27。例如, 在图 5中, 我们显示了使氨的速率与系统中总压强的下降成正比, 比没有吸收要大得多。特别是, 红色圆圈显示的 90 bar 上的反应, 比与吸收剂的反应更不完整, 由蓝色三角形27显示。这是真的, 即使没有吸收剂的反应发生的压力几乎是吸收反应的两倍。在早期的实验中 (这里没有显示), 我们还表明, 该过程的最终转换是约20% 没有吸收剂, 但超过95% 的吸收剂。
反应速率随吸收温度的变化而降低。这在图 6中显示, 它再次报告合成氨为总压力vs时间27。改变反应温度60° c 对反应速率影响不大。这与图 4中的初始速率形成了对比, 它显示了几乎是一个数量级的反应速率的变化。图 4和图 6的结果是不同的, 因为反向反应的效果已经降低, 因此化学动力学不再是对总体速率负责的唯一步骤。

<table border="0" cellpadding="0" cellspacing="0" width="632">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Experimental Apparatus</td>
			<td style="width:131px;"></td>
			<td style="width:119px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Magnesium Chloride</td>
			<td style="width:131px;">Sigma Aldrich</td>
			<td style="width:119px;">7786-30-3</td>
			<td>St. Louis, MO</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Calcium Chloride</td>
			<td style="width:131px;">Sigma Aldrich</td>
			<td style="width:119px;">10043-52-4</td>
			<td>St. Louis, MO</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ultra Pure Hydrogen</td>
			<td style="width:131px;">Matheson</td>
			<td>SG PHYF30050</td>
			<td>New Brighton, MN</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ultra Pure Nitrogen</td>
			<td style="width:131px;">Matheson</td>
			<td>SG G1881112</td>
			<td>New Brighton, MN</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Iron Based Catalyst</td>
			<td style="width:131px;">Clariant/Sud Chemie</td>
			<td style="width:119px;">-</td>
			<td>Charlotte, NC</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Variable Piston Pump</td>
			<td style="width:131px;">PumpWorks Inc.</td>
			<td style="width:119px;">PW2070N</td>
			<td>Minneapolis, MN</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Omega Ceramic Heater</td>
			<td style="width:131px;">Omega</td>
			<td style="width:119px;">CRFC-36/115-A</td>
			<td>Stamford, CT</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">PID Controller</td>
			<td style="width:131px;">Omega</td>
			<td style="width:119px;">CN96211TR</td>
			<td>Stamford, CT</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Signal Conditioner</td>
			<td style="width:131px;">Omega</td>
			<td style="width:119px;">DRG-SC-TC</td>
			<td>Stamford, CT</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Pressure Transducer</td>
			<td style="width:131px;">WIKA</td>
			<td style="width:119px;">50426877</td>
			<td>Lawrenceville, Georgia</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Mass Flow Controller</td>
			<td style="width:131px;">Brooks Instruments</td>
			<td style="width:119px;">SLA5850</td>
			<td>Hatefield, PA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Name</td>
			<td style="width:131px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Pilot Plant</td>
			<td style="width:131px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Electrolyzer</td>
			<td style="width:131px;">Proton OnSite</td>
			<td style="width:119px;">H6 Series</td>
			<td>Wallingford, CT</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Gas Booster</td>
			<td style="width:131px;">PDC Machine</td>
			<td style="width:119px;">3 2500&#160;</td>
			<td>Warminster, PA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Wind Turbine</td>
			<td style="width:131px;">Vestas</td>
			<td style="width:119px;">V82</td>
			<td>Portland, OR</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Chiller</td>
			<td style="width:131px;">Thermal Care</td>
			<td style="width:119px;">SQ Series</td>
			<td>Niles, IL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Water Purifier</td>
			<td style="width:131px;">Elga Pure Lab</td>
			<td style="width:119px;">S-15</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Nitrogen Generator</td>
			<td style="width:131px;">Innovative Gas System</td>
			<td style="width:119px;">NS-10</td>
			<td>Huoston, TX</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Air Compressor</td>
			<td style="width:131px;">Hydrovane</td>
			<td style="width:119px;">HV05</td>
			<td></td>
		</tr>
	</tbody>
</table>

ammonia synthesis at low pressure

氨可通过使用氨选择性吸收剂在低气压下合成。这一过程可以用风能驱动, 在需要合成氨的地区, 可在当地获得合成肥料。这样的风能通常被称为 "搁浅", 因为它只能从可以直接使用的人口中心获得。
在所提出的低压过程中, 氮气是由空气中的变压吸附制得的, 而氢是由电解产生的水。当这些气体可能起反应在大约400° c 在被促进的常规催化剂的存在时, 转换由反向反应经常限制, 使这个反应仅可行在高压。这种限制可以通过吸收氨的钙或氯化镁来消除。这种碱性金属卤化物能有效去除氨, 从而抑制反应的平衡约束。在所建议的吸收增强氨合成过程中, 反应速率可以不受化学动力学和吸收率的控制, 而是由未气体的循环速率来调节。这一结果与传统的小型哈伯-博世工艺的氨水相比是有利的。

中的试装置上莫里斯，锰证明为当地氨制造18，风之可行性，如图 1所示。风力发电，用以使氮气和氢气通过的空气压力回转吸收法和电解水，分别。反应器使用常规催化剂组合的氮气和氢气的气体，使氨。氨是用凝汽器然后分离的。
这里介绍的方法包括进程回收任何未反应的氢和氮。?...

Watch this Scientific Journal Video about Ammonia Synthesis at Low Pressure at JoVE.com

Ammonia Synthesis at Low Pressure

通过使用常规的催化剂和氨选择性吸附剂可以在低压力为原料合成氨气。

低压氨合成

Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in ...

The overall goal of this procedure is to produce ammonia from air, water and wind-generated energy in a low-pressure process with negligible carbon dioxide emissions. This method can help address key issues in ammonia production such as reaction efficiency, product distribution and carbon dioxide emissions. The process uses a solid ammonia-selected absorbent rather than a condenser.Continually removing ammonia from the system decreases the occurrence of the reverse chemical reaction. The main advantage of this process is that it can performed at lower pressure which is safer and less expensive. Cory Marquart and I operate a plant for the conventional process that is 30, 000 times smaller than typical plants.This gives a standard for comparison with the absorbent process. Mike Reese and Cory Marquart are operating the conventional small-scale plant in Morris, Minnesota. Demonstrating the absorption-based process will be Mahdi Malmali, a post-doctoral fellow affiliated with our laboratory.Prior to beginning the process, start up the ammonia generation plant and ramp the catalytic reactor to 440 degrees Celsius. Set the condenser temperature to minus 18 degrees Celsius. Next, turn on the air dryer, the air compressor and the nitrogen generator.Turn on the nitrogen gas booster to fill the nitrogen supply tanks. Turn on the chiller, water deionization unit, electrolyzer and the hydrogen gas booster. Verify that the chiller is operational and cooling liquid is flowing through.Next set the nitrogen inlet regulator to 300 PSI. Open the nitrogen valve to begin pressurizing the process skid. Close the nitrogen bypass valve when the skid reaches 300 PSI.Then, set the hydrogen inlet regulator to 1, 200 PSI and open the hydrogen valve. Once the skid reaches 1, 200 PSI, close the hydrogen valve. Start the skid to begin cycling the one-to-three nitrogen-to-hydrogen gas mixture through the system.After the process has finished, store the condensed ammonia at 150 PSI. To prepare the reactor, use a mortar and pestle to grind the catalyst particles to less than one millimeter in size. Pack the ground catalyst into 0.25-inch tubing.To prepare the absorber, pack 80 grams of calcium chloride or an equivalent amount of another ammonia selective absorbent into a 30-centimeter column with an inner diameter of 2.3 centimeters. Plug the ends of the column with sufficient packing support material to immobilize the absorbent. Install the absorber and the reactor in the experimental apparatus.Heat the reactor to 450 degrees Celsius using the recommended activation temperature procedure while flowing hydrogen through the reactor at 500 SCCM to finish the catalyst activation. Keep the activated catalyst under a blanket of ultra-pure nitrogen gas when the system is idle. To begin the ammonia generation process, close the outlet valve and ramp the reactor to 400 degrees Celsius and the absorber to 180 degrees Celsius.Flush the system with ultra-pure nitrogen gas by repeatedly pressurizing and venting the system. Then, pressurize the system with a one-to-three mixture of nitrogen and hydrogen gases. Stop the nitrogen and hydrogen mass flow controllers.Close the reactor inlet valve. Open the reactor outlet valve and start the recirculation pump. Monitor the reactor and absorber temperatures as the reaction starts and adjust them as necessary to compensate for exothermic processes.Run the process for five hours or until the absorber starts to break through as indicated by a decrease in the change in system pressure over time. Open the nitrogen inlet valve and the ammonia outlet valve and reduce the system to atmospheric pressure. Flow nitrogen through the system at 100 SCCM while heating the absorber for five hours to release the ammonia.The high pressures used in the conventional method are necessary to favor the forward reaction at high temperatures. In the low-pressure separation method, the ammonia is more completely separated before it could undergo the reverse reaction. A significant increase in the rate of conversion was observed relative to the conventional method.The initial reaction rates of the separation method were consistent with published values and separate chemical kinetics experiments. Temperature variation was observed in the initial reaction rates of the reaction absorption method. The overall reaction rate showed much less temperature dependence indicating that the catalytic reaction rate is not a major limiting factor for the conversion rate in the separation method.The absorbent efficiently removed the ammonia from the system, but the capacity of the column decreased after each cycle. Investigation into prolonging the life of the absorbent column is underway. The absorption kinetics were not found to be a significantly limiting factor for ammonia production.The recirculation flow rate was found to correlate with the reaction rate indicating that it is the primary controlling step for the process. This process can make ammonia from air, water and wind. The air and water are sources of nitrogen and hydrogen by pressure-swing absorption and electrolysis respectively.The energy for the process comes from the wind. The Haber-Bosch process is a century-old reaction that feeds a large fraction of the world's population. Trying to improve it has high risk and potentially high reward.Our original idea for this work was to make family farms in rural Minnesota more self-sufficient for their nitrogen fertilizer. The promise of a fuel for energy-short cities by storing wind-based energy as liquid ammonia was an unexpected gain. The key to the absorption-based process is to develop a stable reusable absorbent that efficiently traps ammonia as it is produced.By replacing the conventional condenser with an absorbent bed, we are closer to a cheaper, safer ammonia generation process suitable for small-scale manufacturing.

Research

JoVE Journal

Bioengineering

Gold Nanostar Synthesis with a Silver Seed Mediated Growth Method

黄金Nanostar合成银种子介导的生长方法

The physical, chemical and optical properties of nano-scale colloids depend on their material composition, size and shape 1-5. There is a great interest ...

科研

生物工程

Induction of Adhesion-dependent Signals Using Low-intensity Ultrasound

诱导粘附依赖使用低强度超声波信号

In multicellular organisms, cell behavior is dictated by interactions with the extracellular matrix. Consequences of matrix-engagement range from ...

High Throughput Microfluidic Rapid and Low Cost Prototyping Packaging Methods

In this work, 3 different packaging and assembly techniques are presented. They can be classified into two categories: one-time use and reusable packaging ...

Design and Construction of Artificial Extracellular Matrix (aECM) Proteins from Escherichia coli for Skin Tissue Engineering

Design and Construction of Artificial Extracellular Matrix aECM Proteins from Escherichia coli for Skin Tissue Engineering

设计和人工细胞外基质的构建（AECM）蛋白质<em&gt;大肠杆菌</em&gt;对皮肤组织工程

Recombinant technology is a versatile platform to create novel artificial proteins with tunable properties. For the last decade, many artificial proteins ...

Rod-based Fabrication of Customizable Soft Robotic Pneumatic Gripper Devices for Delicate Tissue Manipulation

娇嫩的组织操纵定制的软机器人气动设备手爪基于杆制造

Soft compliant gripping is essential in delicate surgical manipulation for minimizing the risk of tissue grip damage caused by high stress concentrations ...

Synthesis of Hydrogels with Antifouling Properties As Membranes for Water Purification

水凝胶的合成与防污性能作为膜的净水

Hydrogels have been widely utilized to enhance the surface hydrophilicity of membranes for water purification, increasing the antifouling properties and ...

Quantifying Microorganisms at Low Concentrations Using Digital Holographic Microscopy (DHM)

Quantifying Microorganisms at Low Concentrations Using Digital Holographic Microscopy DHM

用数字全息显微镜 (DHM) 定量化低浓度微生物

Accurately detecting and counting sparse bacterial samples has many applications in the food, beverage, and pharmaceutical processing industries, in ...

Making Conjugation-induced Fluorescent PEGylated Virus-like Particles by Dibromomaleimide-disulfide Chemistry

Dibromomaleimide 二硫化学制备共轭诱导荧光 PEGylated 病毒样粒子

The recent rise in virus-like particles (VLPs) in biomedical and materials research can be attributed to their ease of biosynthesis, discrete size, ...