共查询到19条相似文献,搜索用时 187 毫秒
1.
2.
研究了氨法脱硫产物硫酸铵结晶过程中反应条件对粒径分布以及硫酸铵晶形的影响。结果表明,最佳反应条件为:搅拌速度300 r/min,蒸发温度70℃,结晶溶液pH值5.0。 相似文献
3.
4.
5.
6.
用盐湖卤水提钾后的水氯镁石溶液和生产镁砂副产的氯化铵溶液为原料,研究了制备铵光卤石的工艺条件.当溶液中氯化镁和氯化铵的物质的量比为1∶1时,在溶液pH为6.0、反应温度为85 ℃、搅拌速度为500 r/min、加热蒸发时间为1 h的条件下,在7 ℃冷却结晶4 h,然后过滤烘干,铵光卤石一次结晶产率为60%,二次结晶产率高达80%.测定了铵光卤石在水溶液中不同温度下的溶解度,利用10,20 ℃的溶解度和动力学参数建立了铵光卤石结晶动力学方程.动力学方程证明铵光卤石的低温结晶受单核结晶生长控制. 相似文献
7.
8.
9.
用铁粉和稀硫酸反应制备硫酸亚铁,再用双氧水作氧化剂、铁氰化钾作指示剂制备硫酸铁,最后加入饱和硫酸铵,经过蒸发、冷却、结晶、抽滤制得硫酸铁铵产品。确定了硫酸浓度为3 mol/L,搅拌速度为870 r/min,制备硫酸亚铁反应温度为95℃,制备硫酸铁铵反应温度为45℃和制备硫酸铁铵溶液酸度为pH≤0.5的最佳条件。 相似文献
10.
以90 ℃的Na2CrO4-NaOH-H2O体系相图为依据,采用蒸发盐析结晶的方法从体系中分离铬酸钠晶体,研究了搅拌强度、蒸发速度、结晶温度、晶种添加等因素对工艺过程的影响规律,得到最优工艺操作条件:搅拌强度为能使晶体离底悬浮所需的最小转速;每1 050 g原料的蒸发速率约为140 mL/h;结晶温度为90 ℃;并添加一定量的晶种。在以上操作条件下制备出的铬酸钠晶体粒度较大,尺寸均一。同时研究了不同氢氧化钠浓度下体系压力与沸点间的关系,为铬酸钠结晶过程的温度控制提供了基础数据。 相似文献
11.
利用小型加氢评价装置,通过在Raney-Ni催化剂上对丁炔二醇加氢反应过程中的物料浓度、pH值、反应压力、温度、搅拌速度等工艺条件的调整,考察了各工艺条件对丁炔二醇加氢效果及正丁醇产生的影响。 相似文献
12.
13.
In this paper, uniform spherical poly(urea–formaldehyde) (PUF) microcapsules containing paraffins, which can be used as phase change materials for energy storage, were prepared by in situ polymerization method under high-speed agitation (≥10,000?rpm) without emulsifier. The influence of high-speed agitation on particle size of as-prepared microcapsules and the tightness of microcapsules were also investigated. The results show that, all the microcapsules have <10?μm mean particles-size and narrow-size distribution, and the mean particle size decreases with the increase of agitation rate. Furthermore, when the agitation rate is >16,000?rpm, the effectiveness of reducing particle size by high-speed stirring is not as remarkable as that of lower speed agitation. In order to gain good tightness of PUF microcapsules under the high-speed agitation conditions, the final pH value of reaction solution should be lower down compared with that of conventional agitation. In our investigation, when the agitation rate was 10,000?rpm, microcapsules fabricated at pH value <2.0 were sealed and own good tightness, however, those fabricated at pH value >2.2 were not sealed. 相似文献
14.
在酸性条件下,用硫化钠作还原剂和沉淀剂,还原-沉淀脱除普通工业品羟基亚乙基二膦酸(HEDPA)中的杂质砷。系统考察了硫化钠加入量、溶液pH、反应温度、反应时间、搅拌速度等因素对脱砷效果的影响,其适宜反应工艺条件为:n(硫化钠)∶n(砷)=4∶1,pH=0.5,反应温度50℃,反应时间2h,搅拌速度90r/min。在该工艺条件下脱砷率达99.3%,可制得高品质低含量砷羟基亚乙基二膦酸(HEDPA),其砷的质量浓度为0.28mg/L,可广泛用作日用化学品添加剂和药物合成的原料。 相似文献
15.
用分子蒸馏器浓缩不饱和脂肪酸 总被引:1,自引:0,他引:1
Pharmaceutical oil is obtained from peanut oil by wiped film short path distiller(SPD).The concentration ofeffective unsaturated fatty acids in the pharmaceutical oil is more than five percentages,the evaporation rate is more than25%.The experiment results indicate that the optimum technology parameters for wiped film SPD are that feed flow rateis 131 mL/h,operation pressure is 0.1 Pa,agitation speed is 140 rmp,temperature of feed is 190℃and the best evapo-ration is 260℃. 相似文献
16.
When plastic film packaging is processed for reuse, residual ink colors the polymer and makes the polymer less stiff, weaker,
and denser than the original material. These problems can be avoided if the printing is removed from the plastic film surface.
In this study, a commercial polyethylene film with water-based ink printing was deinked (the ink was removed) using nonionic
surfactants under a variety of conditions, and the effect of some parameters related to the deinking process were quantified
and optimized. Nonylphenol polyethoxylate, ethoxylated alcohol at a pH of 10, and ethoxylated amine at either acidic, neutral,
or basic pH level were identified to be effective at deinking. The hydrophiliclipophilic balance (HLB) value and the cloud
point are useful parameters for characterizing the effectiveness of nonionic surfactants. For optimal deinking, the HLB of
the nonionic surfactants should be as small as possible or the cloud point as low as possible without the deinking temperature
substantially exceeding the cloud point. Information related to scaleup of the process was also developed. Soaking plastic
film in surfactant solution prior to mechanical agitation significantly decreased the needed agitation time to achieve a given
level of deinking. Deinking decreases as the plastic/solution ratio (consistency) increases, and cutting plastic film into
smaller pieces improves the deinking at moderate consistency. Increasing agitation speed also enhances the deinking. Experiments
performed with pilot-sized paper deinking apparatuses demonstrated that deinking of plastic film using surfactants is technically
feasible.
Presented at the 88th AOCS Annual Meeting & Expo, May 11–14, 1997, Seattle, Washington. 相似文献
17.
转氨酶是酶法生产氨基酸工艺中的重要酶种,高产量的酶必须涉及菌体的生长和酶的合成需要.从酶发酵过程的稳健性出发,应用低灵敏度的稳健性设计手段对转氨酶的发酵产酶过程进行了优化设计.通过实验发现通气量和搅拌速度两个工艺参数对发酵产酶结果影响较大,而培养基成分、发酵初始pH值及发酵温度的影响较小.并得到了结果稳定的最优发酵条件:通气量0.6L·min-1,搅拌速度500 r·min-1,温度35℃,pH值6.5,玉米浆2%.经实验验证,发酵结果稳定且符合最优目标值. 相似文献
18.
化学法和机械法从大肠杆菌释放人肿瘤坏死因子 总被引:2,自引:0,他引:2
对化学法和机械法破碎基因工程大肠杆菌以释放人肿瘤坏死因子的影响因素作了考察。在化学法破菌中研究了破碎时间、试剂浓度、溶剂pH值、加入表面活性剂等因素的影响。在机械法破碎中研究了停留时间、装珠量、搅拌转速、细胞浓度等的影响,对操作条件进行了优化。通过对二者的比较,发现机械法破碎细胞效率高,但产生细小的碎片不利后分离;化学法释放产物有选择性,但操作时间长。 相似文献
19.
讨论了反应时间、pH、温度、搅拌速率以及pH调节剂种类和投加量对Mn回收率的影响,确定了利用二氧化碳从含锰废水中选择性分离回收锰的最佳工艺条件。结果表明:在反应时间90 min,pH 6.6,反应温度45℃,搅拌速率600 r·min-1,NaOH投加量2 g·L-1的条件下,锰的回收率为99.79%,出水锰的浓度低于5 mg·L-1,达到《污水综合排放标准》(GB 8978-1996)中总锰的三级排放要求,沉淀物符合《工业碳酸锰标准》(HG/T 4203-2011)合格品技术要求。 相似文献