Assertion: hydrogen chloride | /r/AtLocation | the exhaust gas
Facets:
value: after the reaction with slaked lime
type: TEMPORAL
Source sentences:
text: detecting a concentration (y) of the hydrogen chloride remaining in the exhaust gas after the reaction with the slaked lime;
text: An object of the present invention is therefore to provide a method for removing hydrogen chloride from an exhaust gas discharged from an incinerator, which permits removal of hydrogen chloride contained in the exhaust gas discharged from the incinerator so that the concentration of hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime stably agrees with a target concentration thereof by taking proper measures against a dead time in the control system of the reaction process of hydrogen chloride with slaked lime.
text: The following method using a semi-dry type removing apparatus is conventionally known for the purpose of removing hydrogen chloride contained in an exhaust gas discharged from an incinerator.
text: causing hydrogen chloride contained in an exhaust gas discharged from an incinerator to react with slaked lime in a slurry to form basic calcium chloride;
text: 5 is a graph illustrating an example of change in the concentration of hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime in the case where hydrogen chloride is removed from the exhaust gas by the conventional method;
text: 7 is a graph illustrating an example of change in the concentration of hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime in the case where hydrogen chloride is removed from the exhaust gas by the method of the present invention.
text: In the case where the dynamic characteristic of the reaction process has a large value of dead time as above, it is difficult to control the concentration of hydrogen chloride remaining in the exhaust gas discharged from the reactor 2 after the reaction with slaked lime as described above, by determining the deviation (~y) , ~ ~ ~ 11 -~298960 of the detected concentration (y) of hydrogen chloride remaining in the exhaust gas from the target concentra-tion (yO) thereof, this being a fact
text: With a lower gain in the control system of the reaction process, elimination of the deviation (~y) requires much time even when the deviation (~ y) becomes larger, resulting in deterioration of control of the concentration of hydrogen chloride remaining in the exhaust gas.
text: Fig, 5 is a graph illustrating an example of change in the concentration of hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime in the case where hydrogen chloride is removed from the exhaust gas by the conventional method.
text: 5, control accuracy of the concentration of hydrogen chloride remaining in the exhaust gas is low, largely varying around the target concentration thereof.
text: Therefore, for the purpose of removing hydrogen chloride contained in the exhaust gas discharged from the incinerator to a concentration below the prescribed emission standard value of hydrogen chloride, it is neces-sary for the above-mentioned conventional method to set the target concentration (yO) of hydrogen chloride remaining in the exhaust gas discharged from the reactor 2 after the reaction with slaked lime to a value suffici-ently lower than the prescribed emission standard value of hydrogen chloride to control the concentration of hydrogen chloride remaining in the exhaust gas discharged from the reactor 2.
text: The prediction/elimination mechanism 9 deter-mines a predicted value containing a dead time of the concentration of hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime, on the basis of the target amount of supply (U) of slaked lime into the reactor 2 as determined by the controller 8, and eliminates the dead time from the closed loop of the control system by using the above-mentioned predicted value.
text: Zl = Gp(S)U, not containing a dead time, of the concentration of hydrogen chloride remaining in the exhaust gas after the reaction with ;o slaked lime.
text: Then, the prediction/elimination mechanism 9 enters the thus determined predicted value, Zl' not containing the dead time, into the second multiplying element 11 to multiply the predicted value, Zl' by the transfer function, e LS, representing the dead time, to determine another predicted value, Z2 = Zle LS= Gp(S)e LSU, containing the dead time, of the concentration of hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime.
text: Z3, between the above-mentioned difference (Z3) and the predicted value (Zl) not containing the dead time, and enters the deviation, Ay' = yO - Z4, of the difference (Z4) from the target concentration (yO) of hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime into the controller 8 as the actuating signal.
text: Since the predicted value (Z2) containing the dead time has the function of a predicted value of the concentration of hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime, the above-mentioned difference (Z3) between the predicted value (Z2) containing the dead time and the detected concentration (y) of the hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime becomes Z3 = Z2 ~ Y = 0.
text: Since the predicted value (Z2) containing the dead time has the function of a predicted value of the concentration of hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime, the above-mentioned difference (Z3) between the predicted value (Z2) containing the dead time and the detected concentration (y) of the hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime becomes Z3 = Z2 ~ Y = 0.
text: the detected concentration (y) of the hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime is offset by the predicted value (Z2)
text: contain-ing the dead time of the concentration of the hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime, and thus, the dead time is eliminated from the closed loop of the control system shown in Fig.
text: The deviation (~ y') of the predicted value (Zl) not containing the dead time of the concentration of the hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime from the target concentration (yO) thereof is thus entered into the controller 8.
text: Therefore, when the controller 8 determines the target amount of supply (U) of slaked lime necessary for nullifying the deviation (~ y') by a PID action, for example, on the basis of the entered deviation (~ y'), and adjusts the amount of supply of slaked lime to the thus determined target amount of supply (U) of slaked lime, the concentration of hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime is controlled so as to stably agree with the target con-centration (yO) of hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime.
text: Accor-ding to the method of the present invention, as is clear from Fig. 7, it is possible to remove hydrogen chloride from the exhaust gas in the reactor 2, while causing the concentration of the hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime to stably agree with the target concentration thereof, without largely varying around the target concentration thereof.
text: Hydrogen chloride contained in the exhaust gas discharged from the incinerator comes into contact and reacts with the thus atomized slaked lime in the reactor 2 to form a reaction product in the form of basic calcium chloride (CaC12.
text: Therefore, for the purpose of removing hydrogen chloride contained in the exhaust gas discharged from the incinerator to a concentration below the prescribed emission standard value of hydrogen chloride, it is neces-sary for the above-mentioned conventional method to set the target concentration (yO) of hydrogen chloride remaining in the exhaust gas discharged from the reactor 2 after the reaction with slaked lime to a value suffici-ently lower than the prescribed emission standard value of hydrogen chloride to control the concentration of hydrogen chloride remaining in the exhaust gas discharged from the reactor 2.
text: ~' ~2~8960 Under such circumstances, there is a strong demand for the development of a method for removing hydrogen chloride from an exhaust gas discharged from an incinerator, which permits removal of hydrogen chloride contained in the exhaust gas discharged from the incinerator so that the concentration of hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime stably agrees with a target concentration thereof by taking proper measures against a dead time in - 10 the control system of the reaction process of hydrogen chloride with slaked lime, but a method provided with such features has not as yet been proposed.
text: From the above-mentioned point of view, extensive studies were carried out with a view to developing a method for removing hydrogen chloride from an exhaust gas discharged from an incinerator, which permits removal of hydrogen chloride contained in the exhaust gas discharged from the incinerator so that the concentration of hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime stably agrees with a target concentration thereof by taking proper measures against a dead time in the control system of the reaction process of hydrogen chloride with slaked lime.
text: According to the method of the present invention, as described above in detail, it is possible to remove hydrogen chloride contained in the exhaust gas discharged from the incinerator so that the concentration of hydrogen chloride remaining in the exhaust gas after the reaction with slaked lime stably agrees with the target concentration thereof.
text: This apparatus 1 basically comprises a reactor 2 for removing hydrogen chloride contained in an exhaust gas discharged from an incinerator, a tank 3 for storing slaked lime in slurry, a pump 5 for supplying slaked lime stored in the tank 3 through a supply pipe 4 into the reactor 2, an atomizer 6 for atomizing the supplied slaked lime into the reactor 2, and an electrostatic dust collector 7 for removing a reaction product entrapped in the exhaust gas discharged from the reactor 2.
text: Using the conventional semi-dry type removing apparatus l mentioned above, hydrogen chloride contained in an exhaust gas discharged from an incinerator is practically removed therefrom as follows.