The Ultrasonic Wave Strengthening On Neutralization Reaction With Sulfurous Acid And Calcium Hydroxide And Its Appliction In Cane Juice Clarification

Cane juice clarification is the highest cost and very difficult process in cane sugar mill, moreover it is vital for sugar manufacture and mostly decides the quality of sugar products. Many sugar industrial countries of the world pay more attention to improve product quality and simplify process in sugar production. Cane juice can be purification by techniques such as lime, creosote or sulfurous acid methods. Among them, sulfurous acid method is in common use due to its great efficiency and simple process, however the remains of SO₂ in white sugar were often high, which reduces the quality of the products and depresses the competition ability of sugar factory. This paper tried to improve the sugar quality and reduce the remains of SO₂ by addition of ultrasonic wave to enhance the neutralization reaction with sulfurous. The main contents of studies were as follow:1) The effects of ultrasonic wave (power, action mode and action time) on neutralization reaction with sulfurous acid and calcium hydroxide in water were studied first. Best effect was achieved when the ultrasonic wave acted at the power of 200 W and on the beginning of the addition of milk of lime. In these conditions, the residues of Ca and SO₂ decreased 7% and 47% respectively compared with those without ultrasonic wave.2) Then, the kinetics equation was established according to the conductance variance in solution during the produce of calcium sulfite, and the kinetics equation about nucleus development and crystal growth with or without ultrasonic wave was studied also. It was found that the speed constant of nucleus development was 0.4115 s^-1 and 0.1892 s^-1 under best condition with or without ultrasonic wave respectively. Thus, the ultrasonic wave could shorten the inducement of nucleus foundation and accelerate the development of nucleus. Furthermore, the speed constant of crystal growth (K=0.0024 s^-1) with ultrasonic wave was less than that (K=0.0141 s^-1) without ultrasonic wave. However, the general speed of crystal development was greater with ultrasonic wave than that without ultrasonic wave, when the speed of nucleus development was taken into consideration.3) The infection factor such as power, action mode and action time of ultrasound was studied about their effect on the sulphitation and neutralization. The results showed that the content of Ca²⁺ and SO₂ reduced when the ultrasound acted at the beginning and progress of the neutralization, by contrast when the ultrasound acted at the end of the neutralization reaction, the content of Ca²⁺ and SO₂ increased. The best result was achieved when the ultrasonic wave acted at the power of 300 W and in the progress of the neutralization. In these conditions, the residues of Ca²⁺ and SO₂ decreased 4% and 21.4% respectively compared with those without ultrasonic wave.4) The apparent purity and color variance of sugar juice under different ultrasound power was recorded. The result showed that ultrasonic wave could help to reduce color and improve the apparent purity of sugar juice, as the color decreased 8.4% and apparent purity improved 0.73% in average compared with those without ultrasonic wave.