Concept and communication of CTP and CTS. CTS element.

Any chemical production represents set of a large number of devices in which various engineering procedures (CTP) interconnected among themselves by flows of raw materials, products and energy carriers proceed. As chemical production processes certain raw materials and turns out specific products, it is possible to conclude that all complex of the interconnected devices and flows works in scales of conversion of raw materials and production as a unit i.e. as system.

Set of the devices interconnected by technological flows and operating as a unit in which a certain sequence of technological transactions for the purpose of release of specific products is performed – is called the chemical and technological system (CTS).

It should be noted that devices usually represent rather difficult technological systems, therefore, they can also be considered as CTS. We will consider these options on the example of the three-half-internal column of synthesis of ammonia, which is an ammonia production component (see Fig. 1.1).

Fig. 1.1. Schemes of a column of synthesis of ammonia

a) General scheme of a column (device) of synthesis of ammonia;

b) Operator technological scheme of a column of synthesis of ammonia

 

In one case (Fig. 1.1, a), the column of synthesis is considered as the uniform vertical cylindrical device which, on one branch pipes includes nitrogen hydrogen mix, and on others there is a converted gas. Thus, if there is no need to consider the processes happening in a column, then she can be represented as the adiabatic stoichiometric reactor with the set extent of transformation. In case it is required to consider influence of the processes happening in a column, for example, to determine the required number of the catalyst by layers, activity of the catalyst, the required surface of heat exchange, etc., then it is necessary to consider a column taking into account her elements which are functionally influencing operation of the device, for example, at the level of technological operators (Fig. 1.1, b). In this case it will consist of three layers of the catalyst (poz.141, 143 and 145), two heat exchangers (poses. 133 and 139), two mixers of streams (poses. 142 and 144) and stream divider (poses. 140).

Thus, depending on need, CTS can be considered at any level of complexity of her elements.

The CTS element is called a part of CTS which in concrete consideration is indivisible.

Thus, in a general view, both technological installation, and each her element (which is also technological system, but younger hierarchical level) can be represented in the form of the scheme presented in Fig. 1.4.

Fig. 1.4. Schematic diagram of an element (subsystem) of CTS

 

In this case, to input and output technological parameters (X, Y) belong parameters of technological flows: temperature, an expense, structure, pressure, warmth, etc., to parameters of management (U) – extent of opening of the gate, compressor engine capacity, etc., to parameters of the unit (K) – the current activity of the catalyst, the active surface of the heat exchanger, etc. As input and output, technological parameters characterize flows of substance and energy, both for an operating mode of all installation, and for an operating mode of each its element it is possible to constitute material and energy balances. Thus, output technological parameters will accurately depend on input technological parameters, parameters of management and parameters of the unit:

 

Y = f (X, U, K) [1.1]

 

In this equation, the function "f" characterizes the proceeding processes, which with sufficient degree of accuracy can be displayed through set of physical and chemical regularities of the proceeding processes and connecting change of temperature, pressure, amount, concentration, etc. in these processes. Thus, each CTS element represents the certain subsystem, which is at the same time the CTS element.

For the purpose of classification of the CTS elements, the hierarchical principle is applied. Usually differentiate four main levels of hierarchy of elements (subsystems) of CTS:

1. Standard CTP and their set in scales of machines and devices;

2. The aggregates and complexes representing set of standard processes in scales of productions and their certain sites;

3. Set of productions on the scale of release of products;

4. Chemical company in general.

This division on levels of hierarchy is conditional, therefore, depending on a specific objective there can be a need, for example, to consider standard CTP at the levels of subsystems of their elements (level is lower than the first) or to consider set of the entities in regional scale (level is higher than the fourth). However, upon transition to other levels or in case of dual prosecution of CTS at various levels at the same time, it is necessary to consider the universal principles of creation of elements (subsystems) of CTS and their functioning.

 

Test questions

1. Concept CTS.

2. Main levels of hierarchy of elements (subsystems) of CTS

3. Concept of the CTS element.

4. Schematic diagram of an element (subsystem) of CTS