There are numerous types of devices making it possible to measure the activity of solid catalysts for the usual reactions encountered in the refining or petrochemical industry. These measurements are made under the following conditions:
pressure between 10.sup.5 and 3.times.107 pascals;
temperature between ambient and 750.degree. C;
liquid (hydrocarbons, other organic compounds) and/or gas (generally containing hydrogen) charge. The flow of charge, expressed in volume of charge per unit of catalyst and per hour (VPH), is generally between 0.01 and 10.sup.2 in the case of a liquid charge, between 10 and 10.sup.5 in the case of a gas charge;
shaped solid catalyst (balls, pellets, extrudates).
Although acceptable when it is desired to measure the activity of catalysts under conditions similar to or identical with those achieved in industrial installations, existing devices and particularly those operating at a pressure above atmospheric pressure exhibit a certain number of drawbacks:
the amounts of catalyst required at a minimum are a few cm.sup.3, which can be a serious obstacle in the case of exploratory studies using catalysts whose preparation is difficult or expensive:
in standard installations, activation and bringing to normal operating conditions of certain catalytic systems is long (from several hours to several days), which is linked to the dimensions of the equipment (thermal inertia and large dead spaces);
for the same reasons, the period of a balance is necessarily important, which generally precludes detailed study of initial bringing to normal operating conditions of the catalytic system under consideration;
standard installations are generally not suited to an online automated analysis with a very short response time (size of dead spaces, inertias of the temperature and pressure regulating systems);
finally, complete automation of a standard installation and its control from a decentralized console is a complex and expensive operation.
The gains in accuracy and reliability that can be expected are limited for intrinsic reasons (lack of stability of the catalysts over long test periods) or extrinsic reasons (difficulties in getting free of the fluctuations in the settings of the various operating parameters).
Moreover, the U.S. Pat. No. 4,099,923 describes an automatic unit for catalyst preselection which makes it possible to obtain a preliminary indication of their potential activity. Further, the German publication No. DE 2.425.227 describes an automatic microreactor for the study of catalytic chemical reactions under pressure. But none of these documents suggest making a complete material balance of a chemical reaction under pressure by determining particularly the measurement of the output flow of the reactor, at the high temperature and pressure conditions of the reaction, a measurement that cannot be obtained directly
There is also known and described in French patent No. 2 529.472 a catalytic microunit test device with a system of sampling valves transferred to one another over a gas chromatograph, which implies stopping the reactor particularly to avoid destruction of the catalyst. But this device does not make it possible to make a strict material balance because it does not have on-line analysis of the effluents under conditions of the reaction under pressure.
To succeed in knowing this output flow, it is necessary to determine the composition of the effluent at the output of the reactor, at the temperature and pressure conditions of the reaction. A first object of the invention therefore is to determine the volume composition of the effluent at the output of the reactor at the temperature and pressure conditions of the reaction and particularly at pressures above atmospheric pressure.
Another object of the invention is to establish from the knowledge of the composition of the charge, its flow and the flow of effluents at the output, a strict and complete material balance of a chemical reaction at a pressure above atmospheric pressure and at high pressure levels (for example, at a pressure above 60 bars).
Another object of the invention is to determine the material balance of a reaction by putting into play very small amounts of catalyst, in a repeatable manner, and in minimum time.
Another object of this invention is to eliminate the drawbacks mentioned above.
Another object is the evaluation of the catalytic properties of laboratory preparations without any particular shaping being necessary and with the possibility of being placed under initial kinetic conditions and/or of following rapid bringing to normal operating conditions or rapid deactivation.