Countercurrent drying In the drying process, the drying driving force is relatively uniform, which is suitable for the drying of the materials to be dried. The dust carried by the drying medium is filtered through the wet zone, and the airflow contains less dust. (II) Selection and calculation of the cylinder dryer The selection of the cylinder dryer is mainly based on the characteristics of the material to be dried, such as the moisture content of the material, the particle size and the moisture of the dried product. In addition, should also consider economic factors, such as try to choose low-cost source of heat drying methods, drying methods such as the use of low-quality coal to boil the combustion chamber, while also considering the use of waste heat, and minimize material into the water before drying Wait. Where V 0 — the total volume of the dryer, m 3 ; Where n——— select the number of units, Taiwan; Where D———the diameter of the cylinder dryer, m;
Acidity regulators, also known as pH
regulators, are substances used to maintain or change the pH of food. The
alkali noodles added to the acid face are acidity regulators. It is mainly used
to control acidulants, alkalis and salts with buffering effects required for
food. Each acidity regulator has different acidity characteristics of mild
acidity and acidity.
Acidity regulator is a general term for acids, alkalis and salts that enhance the sour taste in food and adjust the pH in food or have a buffering effect. There are 17 kinds of acidity regulators that are allowed to be used, such as citric acid, potassium citrate, lactic acid, tartaric acid, etc., of which citric acid is a widely used sour agent. Citric acid, lactic acid, tartaric acid, malic acid, sodium citrate, potassium citrate, etc. can be used for various types of food according to normal needs.
Acidity Regulators,Ph Regulators,Acidity Regulator Meaning,Foods For Acidity Regulators WUHAN RUISUNNY CHEMICAL CO. LTD , https://www.ruisunny-chem.com
The indirect heating cylinder dryer is composed of a fixed concentric cylinder mounted outside the axis of the rotary cylinder and directly passes through the combustion chamber as a flue, so that the high temperature flue gas from the combustion chamber is from the concentric cylinder gap of the dryer. Passing, thereby drying the material in the inner cylinder; or in the central chimney peripheral multi-tube return pipe, so that the material of the outer cylinder is heated and dried by the reciprocating flow of hot air. As shown in Figures 6 and 7, respectively, due to the low heat transfer efficiency of indirect heating and complicated structure, the indirect heating cylinder dryer is rarely used. 
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The production capacity of the cylinder dryer is related to the moisture (calculated by the reset percentage) of the dried material entering and leaving the dryer and the drying strength. First, calculate the total volume of the dryer, the formula is as follows:
Q———Processing capacity of drying operation (kg/h according to the weight of solids in the dry matter section;
R 1 , R 2 — the moisture (in weight percent) of the dried material entering and leaving the dryer;
W S ——— Drying strength according to evaporation moisture meter, kg / (m 3 · h).
Dry strength is determined by actual production data for the test or drying of similar materials.
The dryer volume is related to the dry strength, the nature of the dried material, the moisture before and after drying, the temperature of the drying medium at the inlet and outlet of the dryer, the dryer type, the gas flow rate and the quality of the fuel. These factors are determined based on experimental studies and actual production data for drying similar materials.
Based on the calculated total volume, then the number of dryers selected is selected.
V 0 ——— Calculate the total volume of the required dryer, m 3 ;
V———Select a single volume of the dryer, m 3 ;
Determination of the diameter of the cylinder dryer:
β———full coefficient, β value generally takes 20%;
V 2 ——— volume of exhaust gas discharged from the dryer, m 3 /h;
υ 1 ———The airflow velocity at the outlet of the cylinder, m/s;
n———The number of dryers, Taiwan. See formula (2).
Acidity regulators, also known as pH regulators, are substances used to maintain or change the pH of food. It is mainly used to control the acidulants needed for food, alkali agents and salts with buffering effect. Acidifiers have many functional properties that enhance the quality of food, such as changing and maintaining the acidity of food and improving its flavor; Enhance antioxidant effect, prevent food rancidity; Complexed with heavy metal ions, it has the effect of preventing oxidation or fading reactions, stabilizing color, reducing turbidity, and enhancing gelling characteristics. Acids have a certain antimicrobial effect, although the use of acid alone to inhibit bacteria, the concentration required for antiseptics is too large, affecting the sensory characteristics of food, it is difficult to apply practically, but when at a sufficient concentration, a certain acidulant is selected and used with other preservation methods such as refrigeration, heating, etc., which can effectively extend the shelf life of food. As for the choice of different acids, it depends on the nature of the acid and its cost.