摘要:
Concentrated sulfuric acid and/or oleum is prepared by the catalytic oxidation of sulfur dioxide to sulfur trioxide using a gas containing water vapor, SO.sub.2 and oxygen. The catalytic oxidation is carried out in two stages. After the first stage an intermediate cooling of the reaction gas, and absorption of the water vapor content and an intermediate absorption of the sulfur trioxide formed in the first stage are performed. In the second stage the unreacted SO.sub.2 is catalytically oxidized to SO.sub.3 in the absence of water vapor, this SO.sub.3 being absorbed in sulfuric acid. An apparatus for carrying out the process is disclosed including a primary catalysis stage, means for the intermediate cooling of the reaction gas, means for the removal of the water vapor content, means for the intermediate absorption of the SO.sub.2 of the first stage, a secondary stage for the catalytic oxidation of the unreacted sulfur dioxide in the absence of water and an end absorption unit for SO.sub.2 absorption produced in the secondary stage.
摘要:
SO.sub.2 -containing, hot gases are catalytically converted in part in a first contacting stage. The water and the SO.sub.3 formed is removed from the reaction gas. The remaining gas is heated and then supplied to the second contacting stage. The water vapor content in the reaction gas delivered by a first contacting stage corresponds to an H.sub.2 O/SO.sub.3 mole ratio below 1. The reaction gas delivered by the first contacting stage is precooled by an indirect heat exchange to such a temperature that the wall temperatures of the heat exchanger are above the dew point temperature of the reaction gas. The precooled reaction gas entering a condensing stage is contacted in a venturi with cocurrent sulfuric acid of 98.0 to 100% concentration and a temperature of at least 95.degree. C. The exit temperature of the gas from the condensing stage is maintained at least at 120.degree. C. The gas rises in a succeeding absorption stage through a packing layer, which is contacted with trickling sulfuric acid having a concentration of 98 to 100% and a temperature of 70.degree. to 120.degree. C. The dry gas which leaves the absorption stage and has been freed from SO.sub.3 is maintained at a temperature which is as high as or slightly higher than the temperature of the acid as it initially contacts the packing in the absorption stage. The sulfuric acid concentration is controlled by a supply of water into the sulfuric acid in the condensing and/or absorption stage.
摘要翻译:含SO 2的热气体部分地在第一接触阶段被催化转化。 所形成的水和SO 3从反应气体中除去。 将剩余气体加热,然后供给到第二接触级。 由第一接触阶段输送的反应气体中的水蒸汽含量对应于低于1的H 2 O / SO 3摩尔比。由第一接触阶段输送的反应气体通过间接热交换预冷至如此温度 热交换器高于反应气体的露点温度。 进入冷凝阶段的预冷反应气体在文氏管中与98.0至100%浓度的并流硫酸和至少95℃的温度接触。来自冷凝级的气体的出口温度保持在至少120℃ C.气体在接下来的吸收阶段通过填充层升高,该填充层与浓度为98-100%,温度为70-120℃的滴流硫酸接触。离开吸收阶段的干燥气体 已被除去的SO3保持在与吸收阶段最初接触填料时酸的温度高或略高的温度。 通过在冷凝和/或吸收阶段向硫酸中供应水来控制硫酸浓度。
摘要:
A locking device is provided in order to prevent a ceiling-mounted stand comprising one or two arms and one stand head and being part of a ceiling-mounted medical supply unit from falling down should a pivot connection of two arms tear apart. The locking device comprises at least two shell segments (1) that reach around the pivot connection and are provided with a first and a second segment end (3, 4) and with an upper and a lower edge (5, 6) adjacent to each of which an engaging section (7, 8) facing the pivot connection is provided, as well as an upper and a lower washer (9, 29) that is assembled of at least first and second washer segments (11, 12) that are, in the installed state, connected to the pivot connection above and below said pivot connection, whereby the washer segments each comprise engaging sections (13, 14) that are associated with the engaging sections (7, 8) of the shell segments.
摘要:
A motor vehicle having a floor system which has an enlarged thickness in the area of the passenger compartment, the floor system being reinforced for improving the occupant protection. In order to reduce the danger of excessive deformations of the vehicle occupant compartment in the event of a side impact of a passenger car onto the motor vehicle, the floor system has a deflecting slope on its underside, which deflecting slope, starting from the side of the floor system, extends diagonally downward toward the longitudinal center plane of the vehicle.
摘要:
The invention relates to a process for making porous carbon membranes and membranes which can made by this process. As starting material, a porous membrane from an acrylonitril-polymer is used. The starting material is pretreated with a hydrazine solution, followed by preoxidation and carbonization. The process enables carbon membranes to be made with selectively adjusted pore sizes and tight pore size distribution. The pore sizes can lie in the ultrafiltration or microfiltration range. The membranes are suitable for separation processes, in which chemically aggressive media are used and for high-temperature processes. They can be used wherever electrical conductivity of the membranes is required.
摘要:
The thickness of a thermoplastic kneading mass having a temperature of at least 40.degree.C in the feeding region of a roller gap, is measured by scanning in the said feeding region the zone of bare roll to kneading mass and kneading mass to rolling sheet with an infrared radiation receiver of high geometrical resolution defined by a diameter of the measuring field of from 0.5 to 3 mm with a measuring distance of from 0.2 to 3 m, recording the curve of thermal radiation and determining the thickness of kneading mass from the distance of the two points of discontinuity in the recorded curve of thermal radiation with consideration of the ratio of the scanning speed to the speed of registration.
摘要:
A system includes a household appliance, a pedestal and an interface. The household appliance includes a controller and a control panel. The control panel has a control element disposed therein. The pedestal includes a housing having an upper part providing a support surface for the household appliance. The pedestal also includes a drawer disposed in the housing, the drawer including a front panel covering a front of the housing and including a locking device operatively connected by a cable for locking and unlocking the locking device. The interface connects the cable to the pedestal and includes a male/female connector. A first part of the male/female connector is disposed on an underside of the household appliance, and a corresponding part of the male/female connector is disposed on the upper part of the housing of the pedestal so as to contact with the first part of the male/female connector.
摘要:
A membrane is disclosed of polyamide, a copolyamide or a mixture of polyamides, suitable for ultrafiltration and composed of an ultrafiltration skin and a backing layer. The pore size in the backing layer increases with distance from the ultrafiltration skin. The membrane is prepared by dissolving a polyamide in at least 75% formic acid, applying a casting solution, containing about 12-22% by weight polyamide and about 1-7% by weight polyethylene glycol in formic acid which has been brought to a temperature of below about 18.degree. C., as a thin layer onto a carrier foil resistant to the components of the solution, introducing the casting solution on the carrier foil into a precipitation and washing bath, withdrawing the casting solution as a coagulated and washed membrane from the carrier foil, stretching in at least one direction and subsequently drying this coagulated and washed membrane.
摘要:
Process for the thermal treatment of powdered and granulated catalysts, catalyst intermediate products, and inorganic substances, which are usable as constituents of catalysts or as auxiliary agents for the production of catalysts. The known process material is placed on a heated vibrating conveyor and there, in the form of a thin layer, in which the particles of the process material are moved with a larger horizontal and a smaller vertical component, heated and allowed to cool either outside the vibrating conveyor or in a separate vibrating conveyor or in the outlet portion of the first vibrating conveyor.