摘要:
Disclosed is a temperature measuring device. The temperature measuring device includes: a thermo-well tube; and a cable or wire type temperature measuring means which is installed in a thermo-well tube, wherein temperature measuring means has temperature detecting sensors disposed at an intermediate portion thereof, and the temperature detecting sensors can be moved axially in the thermo-well tube by applying tension to both ends of the cable or wire type temperature measuring means. The present invention also provides a reaction tube in which the temperature measuring device is disposed axially, and a reactor including at least one temperature measuring device or reaction tube as described above.
摘要:
Disclosed is a method for producing (meth)acrylic acid comprising a process of recovering (meth)acrylic acid as aqueous (meth)acrylic acid solution from a (meth)acrylic acid-containing gas mixture produced by the catalytic gas phase oxidation of at least one reactant selected from the group consisting of propane, propylene, isobutylene and (meth)acrolein, wherein the recovering process comprises the steps of: (1) feeding the (meth)acrylic acid-containing gas mixture into a quenching tower and condensing it in the quenching tower so as to recover an aqueous (meth)acrylic acid solution from the bottom of the quenching tower, in which some of the recovered aqueous (meth)acrylic acid solution is recycled to the upper portion of the quenching tower so as to condense the (meth)acrylic acid-containing gas mixture; (2) passing the uncondensed part of the (meth)acrylic acid-containing gas mixture from the top of the quenching tower to a distillation tower; and (3) heating the bottom of the distillation tower to separate water-containing impurity components from the uncondensed (meth)acrylic acid-containing gas mixture and to discharge them from the top of the distillation tower. A system used for carrying out the method is also disclosed.
摘要:
Disclosed is a shell-and-tube heat exchanger type reactor that can be used for a process of producing unsaturated acids from olefins via fixed-bed catalytic partial oxidation, which comprises at least one reaction tube, each including at least one first-step catalyst layer, in which olefins are oxidized by a first-step catalyst to mainly produce unsaturated aldehydes, and at least two second-step catalyst layers, in which the unsaturated aldehydes are oxidized by a second-step catalyst to produce unsaturated acids, wherein a first catalyst layer of the second-step catalyst layers, disposed right adjacent to the first-step catalyst layer, has an activity corresponding to 5˜30% of the activity of the catalyst layer having a highest activity among the second-step catalyst layers. A method of producing unsaturated acids from olefins by using the reactor is also disclosed.
摘要:
Disclosed is a simplified method for recovering acrylic acid from a mixture containing acrylic acid, acrylic acid dimer and impurities with high boiling point, in a stable and efficient manner. The method comprises the steps of: introducing the mixture into an acrylic acid recovering device comprising an acrylic distillation unit integrated with an acrylic acid dimer pyrolysis tank; carrying out decomposition of acrylic acid dimmer under reduced pressure and recovering acrylic acid. The method optionally further comprises a step of recycling a portion of the solution obtained from the bottom of the acrylic acid recovering device to the acrylic acid recovering device.
摘要:
Disclosed is a process for producing unsaturated aldehydes and/or unsaturated acids from olefins or alkanes in a fixed bed shell-and-tube heat exchanger-type reactor by catalytic vapor phase oxidation. A heat exchanger-type reactor for use in such a process is also disclosed. In the process, at least one of the first-step reaction zone and the second-step reaction zone is divided into two or more shell spaces by at least one partition; each of the divided shell spaces is independently heat-controlled; a heat transfer medium in the first shell space of the first-step reaction zone or the first shell space of the second-step reaction zone has a temperature ranging from the lowest active temperature of a catalyst layer packed in a reaction tube corresponding to the first shell space of the first-step reaction zone or the first shell space of the second-step reaction zone to [the lowest active temperature+20° C.], when referring to the two or more shell spaces corresponding to the first-step reaction zone sequentially as the first shell space of the first-step reaction zone, the second shell space of the first-step reaction zone, . . . , the nth shell space of the first-step reaction zone, and the two or more shell spaces corresponding to the second-step reaction zone sequentially as the first shell space of the second-step reaction zone, the second shell space of the second-step reaction zone, . . . , the nth shell space of the second-step reaction zone; and the first shell space of the first-step reaction zone or the first shell space of the second-step reaction zone is controlled in such a manner that the first shell space provides a reactant conversion contribution per length as defined in Equation 1 or 2 of 1.2˜2.5.
摘要:
The present invention relates to a method for producing (meth)acrylic acid comprising a process of recovering (meth)acrylic acid as an aqueous (meth)acrylic acid from a (meth)acrylic acid-containing gas mixture produced by the catalytic gas phase oxidation of at least one reactant selected from the group consisting of propane, propylene, isobutylene and (meth)acrolein, and a system usable for the method. The recovery process comprises the steps of: (1) feeding the (meth)acrylic acid-containing gas mixture into a quenching tower and condensing it in the quenching tower so as to recover an aqueous (meth)acrylic acid solution from the bottom of the quenching tower, in which some of the recovered aqueous solution of (meth)acrylic acid is recycled to the top part of the quenching tower so as to condense the (meth)acrylic acid-containing gas mixture; (2) passing the uncondensed part of the (meth)acrylic acid-containing gas mixture from the quenching tower through the top of the quenching tower to an absorption column; (3) absorbing (meth)acrylic acid contained in the uncondensed part of the (meth)acrylic acid-containing gas mixture in the absorption column with a absorption solvent; (4) feeding the (meth)acrylic acid solution resulting from the absorption in the step (3) to a desorption column; and (5) separating the solvent used in the step (3) from the (meth)acrylic acid solution in the desorption column, so that the substance from which the solvent has been removed in the desorption column is fed to the quenching tower, and the separated solvent is recycled to the absorption column. The inventive method is an efficient and economic method which allows a reduction in energy consumption in subsequent purification processes by maximizing the concentration of an aqueous solution of (meth)acrylic solution recovered at the bottom of the quenching tower and minimizing the concentration of (meth)acrylic acid lost from the vent gas of the absorption column.
摘要:
Provided are a security router system for a network and a method of authenticating a user who connects to the system. The security routing system includes: a plurality of physical link ports inputting/outputting packets; a physical layer matching unit transmitting/receiving packets to the physical link ports and generating a media access control (MAC) frame; and a network processor including routing processing means that establishes a transport route for input packets via the physical layer matching unit and processes routing protocols, packet forwarding means that forward the input packets to their destinations, intrusion detection means that classify the input packets based on a packet classification standard and determine whether the input packets are attacks from outside, and user authentication means that determine whether a user is authorized to connect to a router, thereby reducing expenses required to build a network while maintaining security in comparison with a conventional firewall or intrusion detection system, and increasing reliability and safety of the network by preventing harmful traffic since each router performs a network security function.
摘要:
A backlight assembly of a liquid crystal display is provided. The backlight assembly of a liquid crystal display include a lamp for generating light; a light guide plate disposed at a side of the lamp to guide the light; a diffusion sheet disposed on the light guide plate to scatter the light that is incident from the light guide plate, thereby making brightness distribution of light uniform; and a prism sheet including a body part into which a light diffused from the diffusion sheet is introduced and a plurality of protrusion parts arranged in a specific direction, in which each protrusion part is shaped in a scalene triangle prism form and has both base angles different from each other.
摘要:
An apparatus and method for computing a SHA-1 hash function value are provided. The apparatus includes a first register unit including a plurality of registers that store a first bit string of predetermined lengths for generation of a hash function value; a second register unit storing input data in units of second bit strings with predetermined lengths, and sequentially outputting the second bit strings; a third register unit performing an operation on the first bit string of the plurality of registers and the second bit strings output from the second register unit so as to generate and store a third bit string, and updating first-bit string of the plurality of registers based on the third bit string; and an adding unit combining the first bit string stored in the first register unit, the first bit string of the third bit string stored in the third register unit, and the original initial values stored in the first register unit so as to obtain a hash function value. Accordingly, it is possible to reduce the size of the apparatus and stably compute a hash function value at a high speed.
摘要:
A method of balanced object striping and a system therefor are provided. The object striping method includes: transmitting a data write request and receiving an object identifier if the data write request is a first write request regarding the data; determining a first object storage target to store the data by using the object identifier; and striping the data in a plurality of object storage targets starting from the first object storage target to store the data.