Choice of methods and criteria for evaluating the effectiveness of the extraction process from raw materials of plant origin

Scientific and methodological foundations for improving the efficiency of the extraction process and product quality

The solution of the problem under consideration is designed to optimize the complex heat and mass transfer processes of extracting useful components from raw materials of plant origin in order to improve the technical and economic indicators of industrial production. Analysis of literature sources devoted to methods of in-line measurement of quality indicators of raw materials and semi-finished products with acceptable accuracy in a wide range of possible fluctuations of materials showed that in most cases they are unrealizable, expensive and complex in hardware design and are often carried out by laboratory analyzes of periodically taken samples.

Under these conditions, we propose an approach focused on the creation of virtual analyzers, which are software-analytical computing systems that program-algorithmically implement adequate mathematical descriptions that link quality indicators with the current values of the measured technological parameters of extraction processes from raw materials of plant origin.
Currently, useful substances and ingredients extracted from various raw materials are widely used in the chemical and related industries. In this case, methods of extraction with liquid solutions, distillation and a combination of the two methods are mainly used. The disadvantages of extraction are the loss of the most valuable components of the extracted substances and the non-exhaustive extraction of the target product. When using hydrocarbons, alcohol, acids, esters, etc. as a solvent, it is necessary to additionally implement a separate and complex technological method for separating the solvent from the meal, in which the most valuable substances of the final product are lost. When traditional extraction techniques are used, insufficient attention is paid to the problem of environmental protection of the air environment, when traditionally used hazardous and harmful solvents enter the water, soil and air.
The work is devoted to the development of new environmentally balanced and resource-saving technologies that ensure a high degree of rational use of raw materials, complex processing and safe disposal of secondary raw materials for the production of competitive high quality products. Carbon dioxide CO ₂ in the supercritical state was adopted as a solvent for extracting various components from organic raw materials. At the same time, the obtained extracts have a number of advantages compared to extracts obtained by traditional methods:
- high concentration of end products;
- stability during storage and use;
- more clearly uniformity, which is important in standardization;
- ecological cleanliness;
- sterility.
As a solvent, CO ₂ has a high dissolving power, is non-flammable, non-toxic, and in combination with moisture does not corrode metals. Finally, CO ₂ can be obtained in the required amount and purity.
As you know, the thermodynamic state of substances is determined by three parameters: pressure P, density ρ (or volume V ) and temperature T, the so-called state parameters. On fig. 1 shows the P, ρ, T phase diagram of carbon dioxide. The dotted line marks the supercritical region a, b, c . Above the critical point, the density changes monotonically with changes in pressure and temperature. CO ₂ can be used for the extraction of mixtures, soluble substances, by changing the dissolving power of the solvent by successively changing P and/or T. CO ₂ is inert, cheap to produce, easily regenerated due to its high volatility.

Fig. 1. Phase diagram for CO ₂ :

a, b, c - the area of supercritical extraction, where the solubility is most sensitive to changes in P and T. P _c = 73.8 bar (1 bar = 10 ⁶ Pa), T _c = 31.1 ⁰ C.

Despite the fact that in the past two decades, extensive work has been carried out on the research and application of supercritical technology abroad and in our country, there is a need for ideas and theories of a new type, as well as new technology and new equipment that would contribute to a better understanding of the supercritical process. .

When implementing the principle of end-to-end integrated product quality management, the requirements of international standards ISO 9000 1400 series and the provisions of Total Quality Management ( TQM ), the following performance criteria R are adopted :

R = f (D, E, K, P, p, W, I ) , (1)

where D =K*V - efficiency (quality K, volume of output V on time); E = Р_пп/ Z - efficiency ( Р_пп - resources to be consumed; Z - resources used in production); К= f (Р_i) (Р_i, i = 1, …., I – indicators of product quality) - quality of products, services of TS elements of the organizational system as a whole, etc. P = D / Z - profitability (D - gross income, Z - total costs); р = V / Z - productivity ( V - the amount of products produced by the vehicle for a given period of time, Z- production costs); W = f (T_j), j = 1, …., I – quality of working life (T_j – set of factors affecting the quality of working life, I – introduction of innovations – a decisive factor of effectiveness R .

According to the performance criteria, the objective function TS C is formed , which is the product of two objective functions C ₁ and C ₂ :
C ₁ = K * V / Z (2)

This function sets the required volume of products of the required quality K and at the lowest possible cost Z.

For competitive products, the second objective function is formed
C ₂ = c / Z₁ , (3)
where c > 3. Here the price for new products is set as low as possible - c _opt , that is, the principle is observed: high quality K - low price c. General objective function


, (four)

Here Z = Z ₁ * V (Z ₁ - the price of a unit of production).

The purpose of mass production is to improve the quality of products K↑, increase the volume of production V ↑ and reduce the cost of production З ↓:
C ₁ = K↑ * V ↑ / Z ↓ . ( 5 )
The structure of the integrated quality management system involves the functioning of interconnected subsystems of interaction of the complexes "developer (R) - manufacturer (I) - supplier (P₀ ) and "manufacturer (I) - certification body for quality systems and production (OSSKP) - center for standardization and metrology (CSM )"; compositional design of new types of products and compositional improvement of the technological system of the manufacturer.