化学反应工程试卷(部分).doc

精品文档就在这里-各类专业好文档，值得你下载，教育，管理，论文，制度，方案手册，应有尽有-Heterogeneous reaction:a reaction is heterogeneous if it requires the presence of at least two phases to proceed at the rate it does.Homogeneous reaction:a reaction is homogeneous if it takes place in one phase alone.Elementary reaction :such reacyions in which the rate equation corresponds to a stoichiometric equation are called elementary reactions.Nonelementary reaction:when there is no direct correspondence between stoichiometry and rate,then we have nonelementary reactions.Single reaction: when a single stoichiometric equation and single rate equation are chosen to represent the progress of the reaction.Multiple reactions: when more than one stoichiometric equation is chosen to represent the observed changes, then more than one kinetic expression is needed to follow the changing composition of all the reaction components.Space time:time required to process one reactor volume of feed measured at specified conditions.Space velocity:number of reactor volumes of feed at specified conditions which can be treated in unit time.In homogeneous system,(temperature) and (pressure) play important roles on the rate of reaction of definite reaction.The basic equations of reactor designing are (material balance) (energy balance) (kinetic) equations.Multiple reactions may be classified (series) and (parallel) reactions.According to the numbers and types of phase involved,chemical reactions can be divided (homogeneous reaction) and (heterogeneous reaction).There are two procedures for analyzing kinetic date (the intergral method) and (the differential method).Most important factor we must consider is (product distribution) when reactor is employed to fulfill (multiple) reaction.The important factor in comparing designs is (reactor size) when reactor is employed to fulfill (single) reaction.Recycled reactors can be regarded as mixed flow reactor when recycle ratio R =(),and can be also regarded as plug flow reactor when R=(0),it implies the nonideal flow reactor when the value of R between (0) and ().The characteristics of mixed flow reactor:uniformly mixed,same composition everywhere within the reactor and at the exit. the composition doesnt change with time and position.The characteristics of plug flow reactor:fluid passes through the reactor with no mixing of earlier and later entering fluid,and with no overtaking .It is as if the fluid moved in single file through the reactor. the composition only changes with position.The characteristics of batch reactor: uniform composition everywhere in the reactor,but of course the composition changes with time.The integral method:1,guess a particular form of rate equation;2,after appropriate integration and mathematical manipulation,predict that the plot of a certain concentration function versus time should yield a straight line;3,the data areplotted and if a reasonably good straight line is obtained,then the rate equation is said to satisfactorily fit the data.The differential method:1, plot the CA vs. t data,and then by eye carefully draw a smooth curve to represent the data.this curve most likely will not pass through all the experimental points;2,determine the slope of this curve at suitably selected concentration values. These slopes dCA/dt=rA are the rates of reaction at these compositions.3,now search for a rate expression to present this rA vs. CA data,either by (a) picking and testing a particular rate form,- rA=kf(CA).(b):testing an nth-order form -rA=kCAn by taking logarithms of the rate equation.-精品 文档-