Introduction:
The EKOTON Industrial Group has engaged in production and supplying wastewater treatment plants with equipment since 1995. Over the years of work, the equipment assortment has constantly grown – dewatering and filtration of sludge and slurries are among the company development directions. Today EKOTON produces multi-disc screw and roll presses, belt filter presses, chamber-membrane filter presses. The first and the second equipment are better for wastewater sludge dewatering, while the chamber-membrane filter press is more used for technological slurry filtration.
At the end of 2016, PE “Agro-Express-Service” applied to EKOTON company with the task of chamber filter presses production for filtration of the first carbonated juice slurry in Horokhiv Sugar Plant, Volyn oblast, Ukraine. Bankruptcy procedure, owner replacement, a part of metallic installations and equipment removal from the plant had made some complications. In fact, reconstruction of all the technological process stages have been accomplished before the season of work has started. The filtration site was dismantled, there were no basic equipment, pumps, tanks, or cake removal machinery.
Customer – Horokhiv Sugar Plant
Activity – Sugar production from sugar beet
Features – Slurry of first carbonated juice
Before – Equipment was dismantled
Task:
From the technical point of view production of filter presses was needed for a sugar plant with 8000 tons of beets per day capacity, and the density of the first carbonated juice slurry is about 1,18 1,2 g/cm3. Together with technical plant specialists, a joint technological solution was made based on the implementation of three chamber filter presses with an area of 170 m2 and cake thickness of 50 mm each. A technological chart of the filtration site with all necessary equipment: slurry feeding and filtrate discharging, cake washing, cake blowing, water and acid filtering cloth regeneration were also agreed. It was decided to use a belt conveyor for cake removal with unloading into the dump truck.
Work description:
The technological production cycle, including individual design of documentation, took 6 months. After equipment delivery, the installation of the filter presses under EKOTON expert supervision was begun. Simultaneous assembling of the equipment, operation platforms and building constructions was one of the main features of the work. For the same reason it was decided to make the cabling of the chart right on the site. The total time of the work including installation, cabling, connecting, programming with all chart adjustments was more than 2 months. It is important to note that the successful result of the work was achieved only through the joint work of the specialists from the plant and EKOTON Industrial Group, as well as the assembling company.
Gorokhiv Project Data
| Parameter | Value |
|---|---|
| Plant capacity | 8000 tons of beet per day |
| Actual productivity | 6300 – 6500 tons of beet per day |
| Operation mode | 24 hours per day |
| Slurry | slurry of first carbonated juice |
| Slurry density | 1.18 – 1.2 g/cm3 |
| Slurry capacity | 50 – 60 m3/h |
| Sugar content in filtering cake | 0.02 – 0.04 % of beet weight |
| Filtering cake moisture | 35 – 40 % |
Technological and financial viability of the juice and slurry of carbonated juice filtration using chamber-membrane filter presses are well known. Low sugar contents in filtering cake (up to 0.02 % of beet weight) concurrently with a low level of washing filtrate dilution with water (1… 3 %) are the main and the most valuable benefits. The washing filtrate on the plant is taken on lime slaking so there is a possibility of additional cake washing for an extra sugar elution, although the filter press valve-collector system also allows to methodically carry out two-stage cake washing with separate filtrate discharging depending on dissolved solid content.
While the actual amount of beet processing is 6,300-6,500 tons of per day, three filter presses are working with prolonged interruptions between cycles. The common operation cycle of the first carbonated juice slurry filtration can be divided into three periods with approximately equal durations – filtration itself, cake washing and cake removing. Filter press clamping/unclamping, tray operation, cake blowing are significantly shorter. Such time distribution allows to organise three filter press operations in a sequence – only one slurry feeding line and only one washing feeding line are used in the scheme at the same moment. The control system of each filter press “knows” about the state of two others and doesn’t start corresponding operations until it receives a permission from filter presses control systems together with signals from level gauges in corresponding tanks.
It should be noted that efficiency and productivity of first carbonated juice slurry filtration is significantly dependent on the maintenance of the optimum capacities of feeding pumps, cake washing pumps and cake removal devices. For example, the previously installed pump for cake washing had a too low feed (up to 5 m3/h with pressure of 2 bars) which led to long and poor process efficiency. As a result productivity decreased and a high sugar content in the filtration cake was observed. After the pump replacement by a more powerful one was done, the washing process began to run in a normal mode with a flow of 25-30 m3/h at a pressure of 6 bar.
The sugar plant operates seasonally without interruptions, weekends may enable the possibility to make long-time repairs or service. All stages in the technological scheme are of the same importance and filtering of the first carbonated juice is only one of them. A well-adjusted filter press type, coherency in technological decisions and adjustment of optimal operating parameters at commissioning – all this together can guarantee the stability of EKOTON equipment operation in the overall picture of the sugar plant technology.