回收氯仿碱解残液生产甲酸钙

我厂年产2000吨氯仿装置,原采用氯油加石灰乳碱解生产工艺,碱解后的残液全部排放地沟,年排放量达7000多吨,既影响下水排放,又造成极大环境污染,排放下水COD高达800～1000×10~(-6),还造成资源浪费。因此解决甲酸钙回收利用是迫切需要的。为此我们进行了从残液中提取甲酸钙的试验,并在1993年上了一套从碱解残液中回收甲酸钙的装置。1 工艺流程简述碱解后的残液经地沟流入残液地坑,用水环真空泵进行第一次真空吸滤,将清液吸     

湿法脱硫工艺实现“零排放”

目前,我国大部分湿法脱硫工艺浮选的硫泡沫带液量都达到了70％左右,这样就造成熔硫后残液增大。由于残液经高温后其组分发生变化,产生多元复合盐类及有机物,直接回收系统易发生皂化反应,不利于再生系统单质硫聚合浮选。为确保系统稳定,熔硫后的残液间断、部分回收,每天不能回收的残液一般为补充脱硫液量的1／4左右。不能回收的残液只能排放,如果不排放而使之进入系统,就会造成脱硫效率低下,影响系统长周期稳定运行。但排放既浪费辅材,又加大了环保治理难度。排与不排的这对矛盾长期以来困扰业界。     

符合经济环保的湿法脱硫工艺

目前,我国大部分湿法脱硫工艺浮选的硫泡沫带液量都达到了70％左右,这样就造成熔硫后残液增大。由于残液经高温后其组分发生变化,产生多元复合盐类及有机物,直接回收系统易发生皂化反应,不利于再生系统单质硫聚合浮选。为确保系统稳定,熔硫后的残液间断、部分回收,每天不能回收的残液一般为补充脱硫液量的1／4左右。不能回收的残液只能排放,如果不排放而使之进入系统,就会造成脱硫效率低下,影响系统长周期稳定运行。但排放既浪费辅材,又加大了环保治理难度。排与不排的这对矛盾长期以来困扰业界。     

采用汽提塔处理精馏残液

针对常压塔塔底产生的大量精馏残液的问题,采用汽提塔对精馏残液进行处理,使处理后的残液中甲醇和COD含量都达到了国家排放标准,减少了对环境的污染,实现了零排放。     

回收氯仿碱解残液生产甲酸钙

回收氯仿碱解残液生产甲酸钙１．残液处理工序碱解后的残液排出碱解罐时温度为９５～１００℃，排放残液经地沟流入残液地坑后，经水环真空泵进行第一次真空吸滤，清液含１２～１３％甲酸钙至清液贮罐内待蒸发浓缩。吸滤后的残渣再用水浸取出以固态存在的甲酸钙，浸出液也...     

液膜法萃取山梨酸的研究

本文介绍了液膜法处理模拟工业山梨酸结晶残液的实验室工作。山梨酸结晶残液经一级液膜萃取,萃取率达９９％以上,既可大大提高山梨酸的实际收率,亦避免了因排放山梨酸废水给环境来的严重污染。     

远东公司尿素水解技术述评

我国中、小尿素装置工艺冷凝液原设计经解吸塔处理后排放，解吸残液含氨0．07％、尿素1．1％～1．5％。目前绝大多数尿素装置的生产能力已大大超过设计值，而工艺冷凝液处理设备基本没有改造，因此经解吸塔处理后排放的解吸残液中的氨及尿素含量超标，不仅不利于环境保护，而且增加生产成本。     

PVDC皂化残液在隔膜电解槽中的试用

将含有有机物、铁锈、油脂、氯化钠等杂质的皂化残液与精盐水按一定比例送入一台隔膜电解槽电解试用,电解槽各项运行指标符合要求。按PVDC产量2万t计,皂化残液100％回用时年综合效益可达173．5万元。且避免了皂化残液直接排放引起的环境污染。     

聚氯乙烯高沸点残液的综合利用

聚氯乙烯生产装置在氯乙烯精馏过程中所产生的高沸点残液(含二氯乙烷及多利有机氯化物)属有毒有害物质,多数厂均将该残液直接排放。据测算,全国聚氯乙烯行业由此途径每年排出二氯乙烷约七百余吨,这不仅污染了环境,而且也造成了资源上的浪费。经调查,南通市如东拼茶化工厂采用该残液为原料生产三氯乙烷产品的扩大     

尿素装置工艺冷凝液水解技术

我国小尿素原设计工艺冷凝液经解吸塔处理后排放,解吸残液含氨0.07%(质量分率),含尿素1.1%(质量分率).由于绝大多数尿素装置的生产能力大大超过原设计值,最高已达500 t/d,而工艺冷凝液处理设备基本没有改造.因此,实际生产中经解吸塔处理后排放的解吸残液含氨及尿素比原设计值还要高,这不仅对环境保护极为不利,而且增加了消耗,提高了产品成本.     

Methanol Synthesis

Methanol is a basic industrial chemical that is produced in the United States at an annual rate of over one billion gallons [1]. It is used as a solvent in many industrial processes, as a starting material for the production of other compounds, notably formaldehyde, and as a freezing point suppressing agent for gasoline lines and window washing liquids, as well as for many other purposes. Traditionally, methanol has been produced by catalytic hydrogenation of carbon monoxide.     

Methanol Synthesis

Abstract

Methanol is a basic industrial chemical that is produced in the United States at an annual rate of over one billion gallons [1]. It is used as a solvent in many industrial processes, as a starting material for the production of other compounds, notably formaldehyde, and as a freezing point suppressing agent for gasoline lines and window washing liquids, as well as for many other purposes. Traditionally, methanol has been produced by catalytic hydrogenation of carbon monoxide.     

Methanol Synthesis

Methanol, like ammonia, is one of the key industrial chemicals produced by heterogeneous catalysis. As with the original ammonia catalyst (Fe/K/Al₂O₃), so with methanol, the original methanol synthesis catalyst, ZnO, was discovered by Alwin Mittasch. This was translated into an industrial process in which methanol was produced from CO/H₂ at 400?°C and 200 atm. Again, as with the ammonia catalyst where the final catalyst which is currently used was achieved only after exhaustive screening of putative “promoters”, so with methanol, exhaustive screening of additives was undertaken to promote the activity of the ZnO. Early successful promoters were Al₂O₃ and Cr₂O₃ which enhanced the stability of the ZnO but not its activity. The addition of CuO was found to increase the activity of the ZnO but the catalyst so produced was short lived. Current methanol synthesis catalysts are fundamentally Cu/ZnO/Al₂O₃, having high CuO contents of?~60?% with ZnO?~?30?% and Al₂O₃?~?10?%. Far from promoting the activity of the ZnO by incorporation of CuO, the active component of these Cu/ZnO/Al₂O₃ catalysts is Cu metal with the ZnO simply being involved as the preferred support. Other supports for the Cu metal, e.g. Al₂O₃, MgO, MnO, Cr₂O₃, ZrO₂ and even SiO₂ can also be used. In all of these catalysts the activity scales with the Cu metal area. The original feed has now changed from CO/H₂ to CO/CO₂/H₂ (10:10:80), radiolabelling studies having provided the unlikely discovery that it is the CO₂ molecule which is hydrogenated to methanol; the CO molecule acts as a reducing agent. The CO₂ is transformed to methanol on the Cu through the intermediacy of an adsorbed formate species. These Cu/ZnO/Al₂O₃ catalysts now operate at?~230° and between 50 and 100 atm. This important step change in the activity of methanol synthesis has resulted in a significant reduction in the energy required to produce methanol. The “step change” however has been incremental. It has been obtained on the basis of fundamental knowledge provided by a combination of surface science techniques, e.g. LEED, scanning tunnelling microscope, TPD, temperature programmed reaction spectroscopy, combined with catalytic mechanistic studies, including radiolabelling studies and chemisorption studies including reactive chemisorption studies, e.g. N₂O reactive frontal chromatography.     

Deactivation of Copper Metal Catalysts for Methanol Decomposition, Methanol Steam Reforming and Methanol Synthesis

Laboratory and industrial results are reviewed to elucidate the general features of the deactivation of supported copper metal catalysts in various reactions involving methanol as reactant or product. Most catalyst types are based on Cu/ZnO formulations that contain stabilisers and promoters such as alumina, alkaline earth oxides and other oxides. These additional materials have several roles, including the inhibition of sintering and absorption of catalyst poisons. All copper catalysts are susceptible to thermal sintering via a surface migration process, and this is markedly accelerated by the presence of even traces of chloride. Care must be taken, therefore, to eliminate halides from copper catalysts during manufacture, and from reactants during use. Operating temperatures must be restricted, usually to below 300°C.In methanol synthesis involving modern promoted Cu/ZnO/Al₂ O₃ catalysts neither poisoning nor coking is normally a significant source of deactivation; thermal sintering is the main cause of deactivation. In contrast, catalyst poisoning and coking have been observed in methanol decomposition and methanol steam reforming reactions.     

低温甲醇洗装置甲醇污染物分析

1999年大检修结束后开车过程中发现低温甲醇洗工段工况严重恶化,几台缠绕式换热器相继出现换热能力下降、阻力增大的现象,尤其是1#、2#贫甲醇冷却器情况更为严重.系统中的甲醇遭到严重污染,装置中导淋排出的甲醇颜色发黑.整个低温甲醇洗工段表现出冷量严重不足、循环量不平衡、仅能维持50%系统负荷,生产无法正常进行.     

适合联醇或单醇的变换工艺

对甲醇生产变换工艺的配置进行了讨论;结合国内外实际工况,分析了在低汽气比条件下中变催化剂的过度还原问题;从工艺流程、设备配置、工业应用等方面阐述了适合于联醇或单醇生产的低温变换工艺。     

均温型甲醇合成塔在大型甲醇装置中的应用

介绍了Φ3000mm均温型合成塔在200kL／a甲醇装置上的运行情况。两年来的实际运行情况表明,均温型合成塔具有床层温度分布均匀、操作弹性大、CO单程转化率高（〉75％）、结构简单等特点,应用前景广阔。     

低温甲醇洗甲醇再生塔的除垢研究

低温甲醇洗甲醇再生塔垢样坚硬，机械清洗困难，通过试验确定了一种复合化学清洗剂配方（碱性物 SAA 有机溶剂 络合剂），除垢完全，有较好的使用价值。     

低温甲醇洗甲醇消耗高及甲醇水塔问题分析及对策

首先,针对装修跑冒滴漏,废水外送损失与气相夹带所导致的低温甲醇洗甲醇消耗高的问题,采取了强化检测力度,调整工艺指标与设备改造调整等多种方式,改善低温甲醇洗甲醇消耗高的问题。其次,对甲醇水塔中存在的液泛问题,塔盘较脏以及灵敏板上下温度差较高等多种问题进行分析与探讨,并提出优化对策,希望能有效提升生产效率及生产水平。     

精甲醇及MTO级甲醇精馏工艺技术进展

重点介绍了甲醇精馏工艺中双塔和三塔精馏流程,对比了两种工艺的投资消耗,为甲醇生产企业的精馏流程节能减耗提供参考。此外,对发展前景较好的甲醇制烯烃(MTO)产业,针对MTO级甲醇在原料方面的特殊要求,对MTO级甲醇精馏工艺进行了详细描述,以期对甲醇制烯烃(MTO)产业提供技术支持。