2. Bench Scale Calorimeter

Primarily a lattice stirrer is used.

This relation stands to reason, because it is evident that

Barlow wheel [2]

The Barlow wheel, from 1822, is considered to be the historic forerunner of the DC disk-armature motor. It consists of a pivoted copper disk S in a vertically oriented magnetic field of a strong permanent magnet M. The conductive connection from the copper disk to the conductive wire takes place via a mercury batch R.

The essential constituents of a modern DC disk-armature motor (Brown, Boveri & Cie. AG, Mannheim) connected to a tachometer. Magnetic return path via a ferriferous motor jacket.

Arrangement of conductive wires of rotor disk [7]

d _Torque generated mechanical torque per unit of the electric current strength I.

k _Motor generated electric voltage of the DC disc armature motor (running without load) at one revolution N in unit of time.

k _Tacho generated electric voltage of the DC disk armature tachogenerator (speedometer) at one revolution N in unit of time.

In fact, the preceding baseline must be completed by a term that takes into account a small heat exchange with the laboratory via the insulated inlet pipes and the cover of the measuring kettle. The heat exchange varies with a temperature programme change T ₂. This term usually varies approximately linearly based on experimentation. Hence, it is sufficiently integrated in the linearly approximated evaluation of p _B(t).

Only when p(t > t _E) agrees with \( p\left(t<0\right)={p}_0 \) the reaction is really finished at the point in time t _E.

Existing when the temperature T ₂ does not change too quickly.

Intermediate- and socle thermostat consist mainly of welded spiral tubes with turbulent flow, the socle thermostat with an utmost quick throughput of a liquid with the constant entry temperature, e.g. from a public supply (Fig. 2.11).

The usual temperature rise produces dT ₂/dt = dT ₁/dt ≅ dT _m/dt as well as T ₁ = T ₂ = T _m + ∂T, with ∂T ≅ const. A very quick temperature rise causes dT ₂/dt = dT ₁/dt ≠ dT _m/dt as well as T ₁ = T ₂ = T _m + ∂T, with ∂T ≠ const.

q _Mi represents the sum of the caloric power of the physical and physicochemical processes during and occasionally after dosing or injection (Chap. 6). The heat of mixture Q _Mi is liberated usually instantly during the injection of mixture to start the reaction, with the result that the pre-starting temperature \( {T}_2\left(t<0\right) \) jumps abruptly at \( {t}_0=0 \) to \( {T}_2\left(t<0\right)+\updelta {T}_0={T}_2\left(t=0\right) \) (Fig. 2.30). C ₂ · δT ₀ corresponds to the liberated heat \( {Q}_{\mathrm{Mi}}={\displaystyle \int {q}_{\mathrm{Mi}} \cdot \mathrm{d}t} \). When the mixing process does not occur instantly, a kinetic analysis can only be approximated because (q + q _Mi) is not easily analysable, i.e. to split into q and q _Mi. The course of the rate of heat release q _Mi should be determined before the calorikinetic measurements are made, or Q _Mi should be compensated as far as possible by the use of an appropriately warmed-up injection mixture to start the reaction kinetic measurements.

The plot of ln T ₂ versus time gives a curve which turns into a straight line. From the transition t _E can be deduced, see e.g. Eqs. (2.25) and (2.26).

For measurements prior to the start of the reaction the measuring kettle must be filled with a solution of all components without the reactant for the start of the reaction, and for measurements after the reaction with the completely reacted mixture, with it filled up each time to the volume equal to that after the start of the reaction.

See Sect. 4.​2.​1.​1.​1.​1.

Using a conventional stirrer, the flow takes place continuously but weakly pulsating as a result of the following causes:

For a flooded flow measuring kettle a circular pendulum mixer is recommended for use instead of a conventional stirrer (Sect. 2.5, Fig. 2.39).

If the reactant solutions being dosed are not brought to the temperature of the measuring kettle, then q _Mi consists of the rates of heat release due to both physical dosing (physical heat \( g \cdot {c}_{\mathrm{p}} \cdot \left({T}_{\mathrm{Laboratory}}-{T}_2\right) \) and physicochemical mixing (physicochemical heat).

During quasi-continual equilibrium, the absolute amounts of the caloric evaporation power q _E in the measuring kettle (temperature T ₂) corresponds to the thermal condensation power q _C in the condenser kettle (temperature T ₃), that is, the sum of the powers cooling the vapour from temperature T ₂ down to T ₃ and subsequent condensation with temperature T ₃.

The prerequisite of such a measuring mode is the initiation of a change in temperature.

See Sect. 4.​1.

This is illustrated, without restriction of the universal validity, by a monomolecular reaction of order 1, see 4.2.1.1.1.3

C _Mt is relatively independent of temperature, more or less. C _F, however, varies with changes in temperature. However, because of the generally moderate temperature fluctuations in the tank reactor, its influence can by first approximation also be neglected.

The batch of the tank reactor is as follows:

The dosage with constant mass rates g _i is as follows:

The weighted average method yields the following results (neglecting the effect of changes in individual substances due to the reaction):

Average specific heat c _p(t) of reaction mass:Average density ρ(t) of reaction mass: