Discussion on Application Process of Filter-free Vacuum Filtering Machine

The application process of sucrose filter cloth-free vacuum suction filter in Guangxi Wu Xianglin Lin Xingsheng (Guangxi Institute of Machinery Industry and Research Institute 530001) compared the problems that should be paid attention to in use.

1 Overview No filter cloth vacuum suction filter has the advantages of no sewage discharge, low conversion of dry filter mud, high production efficiency and high degree of automation. It has been applied by foreign sugar production enterprises in raw sugar production and sulfite deposition pond mud. filter. Domestically, it was first introduced by the East Asia Group in Guangxi in the mid-1990s. Based on the digestion and absorption, Guangxi Machinery Industry Research Institute carried out a number of innovations with independent intellectual property rights and developed second-generation products that have been used in many sugar factories. Due to the short use time of filterless cloth vacuum suction filter in China, some sugar companies still have doubts about the use of the equipment, such as whether the reflux of filter juice will affect the quality of sugar and whether it will cause the temperature of sedimentation tank to decrease. Whether or not there will be a large amount of sugar conversion losses, the author hopes to clarify these issues through joint discussions.

2 The use of non-filter cloth vacuum suction filter The use of non-filter cloth vacuum suction filter use process. The mud flows from the sedimentation tank into the mud agitator, and after being evenly mixed with the bagasse mash, it enters the mud filter tank without filter cloth vacuum filter. Under the action of vacuum, the filter juice enters the high and low vacuum tanks through the juice pumping system, and the juice is sucked. The pump filtrate is withdrawn to the sedimentation tank. The self-evaporating steam and the leaked air are removed by the vacuum system through the condenser.

There are two ways to add bagasse crucibles. One is to transfer the wind from the bagasse scraper of the press workshop into the cyclone separator and the shutoff fan to enter the mud agitator; the other method is to remove the pulp from the baling chamber directly by a fan. The bagasse was sampled and transferred to the whirlwind separator and the closed-air fan to get rid of it. Xie Xie: Thanks to Guangxi Dongmen Sugar Factory, Guizhong Sugar Factory, Laibin Sugar, Yunnan Ruili Sugar Factory, and Guangxi Machinery Industry Research Institute, Marketing Department of Lin Jiarong and Hu Weiping. This article provides some of the data and materials.

Mixer. Our hospital has recently adopted a new bagasse addition method to add cane meal directly from the press shop. This method is particularly suitable for manufacturers with larger sedimentation basins.

The function of the balance tank is mainly to prevent the vacuum from being too high and unable to extract juice. At the same time, it can also act as a liquid seal to prevent evacuation. Each factory can decide whether to use it according to its actual situation.

There are three ways to direct the sedimentation of the filter juice: one is the direct reflux precipitation; the second is to return the mixing tank and the mixed juice through the neutralization tank and then back to the sedimentation tank; the third is to return the sedimentation tank after the neutralization tank . The three methods have their own merits and can be selected according to their own process conditions.

3 Comparison of the Performance of No Filter Cloth and Filter Cloth Vacuum Suction Filter and Frame Filter Press From the comparison of Table 1, it can be seen that among the three types of equipment, the dry mud filtrate has the lowest conversion, the highest production efficiency, and the labor intensity of workers. The lowest is the non-filter cloth vacuum suction filter, and no filter cloth vacuum suction filter can be table 1 Comparison of the performance of three kinds of filter equipment The use of filter cloth suction filter without filter cloth suction filter frame filter press dry Filter mud rotation degree 10~12% 3 %60% Lower production efficiency High and low sewage discharge More zero-less Workers' labor intensity Less large filter juice conditions Can directly boil sugar Reflow sedimentation tank can directly boil sugar 400 to achieve zero sewage Emissions, which the other two devices cannot do. Of course, filter cloth without filter cloth vacuum filter can not directly boil sugar, this is the fly in the ointment, but in terms of overall performance, no filter cloth vacuum suction filter is still the best, so when the device becomes the other two The first choice for upgrading equipment.

4 the use of the process of discussion 41 non-filter cloth vacuum suction filter for the amount of sugar cane problem with Guangxi Machinery Industry Research Institute of several specifications of the type of non-filter cloth vacuum suction filter as an example, the applicable squeeze in Table 2 Table 2 Filter area and applicable amount of pressed sugarcane Model Size Filter area (m2/tablet) Applicable daily press volume (t/d) No filter cloth The applicable vacuum filter has a larger relationship with the specific conditions of each plant. Such as the crushing plant sugar cane crushing rate, curved sieve gap and filter mesh number, sugar and sugar cane and sedimentation tank size. Since the drum speed can be adjusted and the filter speed can be adjusted appropriately, the applicable squeeze amount can be changed within the range shown in the above table.

42 Problems with the size of the sedimentation tank The use of a filter-free vacuum suction filter followed by a reflux sedimentation tank requires a large volume of sedimentation tank. However, due to the lower concentration of the filtrate than that of the mixed juice, the reflux of the filtrate and the mixed juice After the mixing, the sedimentation rate of the juice is accelerated, and the speed of the juice decanting is also accelerated. It is not necessary to increase the volume of the sedimentation tank because it does not return a large amount of filtrate. Generally, the ratio of sugar sludge to sugar cane is 25%~30%. After tests and theoretical calculations, it is considered that the use of vacuum filter without filter cloth needs a larger precipitation than the original technology. Therefore, manufacturers who are prepared to use vacuum filter without filter cloth should Pay attention to this change, if the original sedimentation tank volume is relatively tight than the reflux filter juice on the settlement area of ​​the reflux filter, then use a non-filter cloth vacuum suction filter, you should increase the sedimentation tank volume or modify the sedimentation tank internal structure, Otherwise, the phenomenon of precipitation in the sedimentation tank may occur, which may affect the color value of white sugar due to poor precipitation.

43. Problems Concerning Degree of Rotation The degree of rotation of the filter mud depends mainly on the amount of water and water in the spray, the speed of the drum, and the degree of vacuum. The amount of spray water and the temperature of the water have a decisive influence on the degree of rotation of the sludge. The more spray water, the higher the temperature and the lower the degree of light transmission. The rotation speed of the drum also has a certain influence on the degree of rotation of the sludge. The faster the rotation speed, the thicker the mud mud thickness is, which is conducive to the reduction of the degree of rotation, but the acceleration of the rotation speed causes the mud mud layer to be sprayed in the same corner. The time for washing the water is shortened, which will increase the degree of light transmission. Therefore, the effect of the rotation speed of the rotating drum on the degree of rotation of the filter mud is non-linear, but there is an optimum value. The thickness of the mud is preferably 3 to 6 mm. The degree of vacuum also has a certain influence on the conversion degree of the sludge. The higher the vacuum degree of the low vacuum tube is, the thicker the mud layer will be, and the degree of conversion of the mud will increase. From the actual production point of view, the degree of rotation of the filter mud is not as low as possible, but there is an economic degree of filter mud conversion, because the reduction in the degree of rotation of the mud is at the expense of the amount of spray water, spray water The addition of evaporation increases the amount of evaporation in the subsequent process, and the cost is also increased. The dry mud filtering degree is preferably about 3%. 44 Problems with the settling tank temperature The effect of the reflux flow on the temperature of the filter cloth without direct filtration from the filter cloth of the filter cloth vacuum filter can be seen from the figure. The larger the return flow of the filter juice, the greater the influence on the temperature. Therefore, when using a non-filter cloth vacuum suction filter, how to take measures to minimize the temperature drop in the sedimentation tank is a problem worthy of discussion. Each plant can take the following measures according to its own actual conditions: A, increase the secondary heating temperature so that The temperature of the juice is appropriately high.

B. Raise the water temperature of the suction filter and ensure that the water temperature is above 85 °C.

C. Filter juice is improved when it is returned to sedimentation tank. a, filter juice back to the mixed juice box.

c. Neutralization juice enters the sedimentation tank as far as possible.

In the case of sufficient secondary heating capacity, we suggest that the filter juice directly back to the sedimentation tank, which can reduce the residence time of the filtrate and reduce the conversion loss.

Of course, some manufacturers require us to take measures to prevent the filter from returning to the sedimentation tank. Theoretically speaking, this can be achieved, but economically speaking, using another set of equipment to process the filter juice not only requires additional equipment investment, but also adds freight, so it is not necessarily desirable. From the perspective of cost, the filter sedimentation tank is the most economical, and some users require that the filtrate does not return to the sedimentation tank mainly based on two considerations. One is that the sedimentation tank volume of these manufacturers is not enough, and there is no need to expand the filter tank. The sediment does not return to the sedimentation tank, which can reduce the pressure in the sedimentation tank; second, it is believed that the reflux of the filter juice will cause a conversion loss of sugar. Regarding the first question, the author thinks that the best solution is to improve the internal structure of the sedimentation tank and improve the sedimentation effect of the mud.

As for the second question, the following discussion is devoted.

4.5 The sugar loss of the reflux filter was calculated based on the data provided by the Sugarcane Sugar Industry Handbook. The sugarcane juice at pH7. At 100C, the sugar conversion per hour was 0.021%. The dwell time we took was 2 hour. From the figure, we can see that the 2500 tons of sugar mills in the daily pressing process can lose less than 60kg of sugar per day under the normal process conditions. This is due to the decrease in the conversion of filter mud due to the non-filter cloth vacuum suction filter. The amount of sugar recovered is only fractional.

We can make a simple calculation. The use of non-filter cloth vacuum filter dry filter mud average degree of rotation to take 3.5%, dry filter mud on the cane ratio to take 1.5%, the use of a filter cloth vacuum suction filter dry mud conversion average take 10%, dry filter The ratio of sludge to cane ratio is 1.2%, then use a filter-free vacuum suction filter to recover more sugar 2500X 10%-2500X1.5%X3.5%=2402 tons per day, deducting the sugar conversion loss caused by the second filter backflow. More sugar 2.34 tons can be recovered every day. Therefore, the use of non-filter cloth vacuum filtration filter backflow sedimentation tank will produce a small amount of sugar conversion loss, but due to the sharp decrease in the conversion of dry mud mud, so the recovery rate will still be significantly improved.

4.6 Effect on the quality of white sugar The use of a non-filtered vacuum suction filter will have a significant impact on the quality of white sugar. There are many factors that affect the color value of white sugar. It is necessary to theoretically discuss whether the use of non-filter cloth vacuum suction filter is It will be very difficult to have a noticeable effect on the color value of white sugar. Let's look at this problem from the use of several plant operators. The Dongmen sugar mill used a non-filter cloth vacuum suction filter for three consecutive crop seasons, and the first-stage sugar yield was 93.2% in 1998/1999 crop season before use, and the first crop sugar was used in the three crop seasons from 1999 to 2002 after use. The yields were 98.2%, 100%, and 100%. Yunnan Ruili Sugar Factory used a crop season in the 2001/2002 crop season, with a primary sugar yield of 97.5% (of which the largest (down to page 54) 2 Thai sugar industry using IT technology to improve the benefits of sugarcane According to Bangkok on January 16, 2002, Thailand's largest sugar group WangKanaiGroup has established a Gan Lu Information Technology Center to improve the company's management efficiency and production efficiency.

The project's starting capital is about 11 (1) million yen (Thailand currency unit) which includes a remote sensing system, global positioning system (GPS), geographic information system (GIS) and database system. The manager of the center, S. Na Chiangmai, explained that once the company uses the information available on Deerfield, it can reduce intangible debt by 50% and reduce the impact on those sugarcane farmers who have borrowed privately to plant sugarcane because they have not entered into a contract. In addition, sugarcane fields can be better managed.

There are approximately 400,000 rai (Thai land units) sugar cane planted in 14 provinces. The group's annual revenue is about 6,000 million baht, 70% of the sugar output, that is, 450,000 tons are exported to Europe, the United States and Japan, and the rest are domestic sales. According to T.Na Wangkanai, the group’s business manager, the main purpose of the company’s implementation of this technology in the sugarcane field is to know exactly how much of the land area can be used to grow sugar cane, which type of soil is suitable for planting sugar cane and the analysis of sugar cane that can be expanded area. The group purchased NASA's remote sensing satellite information system to classify available land. There are nine sets of GPS tool systems for the sugarcane field and a set of Kangby iPAQ small computer systems with integrated GPS tools.

The information obtained can be recorded.

Mr. Sittide said that through the use of this set of IT technology, the company can know whether each farmer can plant cane according to the agreement. At the same time, the computer can also record dates for cane growth to improve sugar cane quality. All information recorded by the company's GPS, remote sensing, and GIS systems can be stored in the company's database management system, which can be used to improve the company's product quality and improve management efficiency. For example, in the past, sugarcane planted by a family of sugarcane farmers had a production capacity of 8 tons per cane. However, if there is information provided by new IT technology, Wang Kanai Group can produce up to 25 tons of sugarcane per cane in the sugarcane field where it is tested.

This information can also be reported to sugarcane farmers. WangKanai has established a website WWW.WANGKANAI.COM to provide better technology to help grow cane. The Wang Kanai Group also plans to expand the company's GPS information capacity to enable traceable cane and sugar trucks to better manage delivery vehicles. The IT system will record the amount of sugar carried by each vehicle, from its start from the sugarcane field to the sugar mill and finally to the market. The IT system will also record the amount of sugar carried by each vehicle to reduce theft.

(Su Yi compiled) (Rights Editor: Niu Gong) (on page 43) Part of the secondary sugar is insoluble in water exceeded) than before use. Guizhong Sugar Factory used it for a period of time in the late cropping season of 2001/2002, and the primary sugar yield increased compared with that before use. In some manufacturers, the volume of the sedimentation tank is not large enough, and the use of a non-filter cloth vacuum suction filter to return juice needs to occupy a certain volume, so the juice is difficult to juice, there are more secondary sugar. From the actual use of the above several sugar plants, as long as the sedimentation tank volume can meet the requirements, the use of non-filter cloth vacuum suction filter will not affect the color value of white sugar.

Finally, special reminder manufacturers who are preparing to use a filterless vacuum suction filter must pay special attention to the following two points: First, the reflux of the filter requires the volume of the sedimentation tank to be about 15% larger than the original process. If the volume is not enough, it must be bulky or improved. Internal structure.

Second, the secondary heating capacity should be sufficient. Returning to the sedimentation tank of the filter juice will cause the precipitation tank temperature to drop, so the secondary heating temperature must be increased.

If the above two can't be satisfied, it will inevitably cause difficulty in the juice, affect the quality of the clear juice, and thus cause the problem of high white sugar color value.

5 Conclusions The characteristics of the use of non-filter cloth vacuum suction filter are: no drainage of washable filter cloth, low conversion of dry filter mud, high production efficiency, high degree of automation, compared with the traditional mud filter equipment, has obvious The advantages are the first choice for upgrading traditional equipment.

Because the reflux of the filtrate requires a large sedimentation tank volume of about 15% compared with the traditional process, at the same time, the secondary heating temperature should be appropriately increased to prevent sedimentation of the tank top cage and ensure the quality of white granulated sugar.

Filtration reflux causes loss of conversion of sugar but is very small. As the dry mud filtration can be controlled under 5%, the total sugar recovery will be significantly improved.

(Rights and Permissions: Niu Gong)

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