SU1230635A1 - Method of cleaning filter partition - Google Patents

Description

The invention relates to methods for cleaning a filter septum from soils or from contaminated auxiliary granular material without disassembling the filter, mainly for filters, spraying polymer solutions in the chemical fiber industry, as well as in other sectors where it is possible to change the viscosity of the filter fluids

The purpose of the invention is to improve the quality of cleaning of the partition by a more intensive non-decreasing in time and uniform over the surface of the partition effect of the filtrate on the particles removed from the filter partition.

The drawing shows an installation diagram for implementing the method.

The installation includes a pump 1 for supplying liquid for filtration and for returning the filtrate back, for cleaning the partition, filter 2, capacity for filtrate 3, heat exchanger 4.

The method is carried out as follows.

The pump 1 feeds the suspension to the filter 2. And the filtrate, in addition to direct ingress to the consumer, also accumulates in the tank 3. After the filter-partition clogging, the suspension is stopped on the filter and the shut-off valves are switched so that the pump continues to work through the partition wall of the filter, in turn, 1.M current, with the filtrate previously passing through the heat exchanger: 4, due to which its temperature drops and its viscosity increases. If the pump remains unchanged, the pressure on the partition wall and contaminating particles are stronger with a more viscous fluid. This ensures high quality filtering of the baffle.

Example 1. Filter the solution of aromatic polyamide in sulfuric acid through a porous metal-ceramic septum using an auxiliary substance. Solution viscosity 180 Pas at 70 C. Initial pressure drop across the partition with a pore size of 150 µm and a grain size of the auxiliary substance of 100 µm PO 0.4 MPa. When reaching at the end

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filtering a pressure drop of 1.6 MPa, the stop valves are switched to supply the filtrate with a working pump to countercurrent filtration. In this case, the filtrate is cooled with a gradual increase in the supply of refrigerant to the refrigerator. A continuous viscometer installed after the heat exchanger shows an increase in viscosity at a rate of 0.54 Pas per second, i.e. 0.3% per second from the initial viscosity. With an increase in viscosity at a rate of less than 0.3% per second of the initial viscosity, the degree of purification at the same flow rate of the filtrate decreases. When viscosity is 216 Paz, i.e. 1.2 times higher than the initial one, the viscosity increase ceases, wait for the complete passage of the solution with increased viscosity through the filter septum and stop the pump. Continue filtering the solution. The differential pressure is equal to the initial 0.4 MPa. The partition is cleared completely. By increasing the final viscosity to less than 216 Pas, complete cleaning of the septum is not achieved. When pushing a solution with initial viscosity through the partition wall, the degree of cleaning does not exceed 80%.

Example 2. Filter the solution of an aromatic polyamide in dimethyl acetamide through a metal-ceramic partition. The concentration of the polymer is 5%, the viscosity is 60 Pas at 24 ° C, Pp 0.22 Sha, P 0.8 MPa. The purification is carried out analogously to example 1. At the same time, the viscosity increases at a rate of 6 Pas for 1 s, i.e. by 1% per 1 s of initial viscosity. After viscosity reaching 108 Pas, i.e. 1.8 times higher than the initial one, cooling is stopped, waiting for the complete passage of the solution with increased viscosity through the filter partition and turning off the pump. Continue filtering the polyamide solution. The pressure drop is 0.25 MPa, i.e. slightly higher than the original. The partition is almost completely cleaned.

Example 3. Filter the viscose through a porous ceramic partition. Viscosity of viscose 9 Pas at 5 18 С, Р 0.1 MPa; P 0.8 MPa. Clear the partition as in examples 1 and 2. Cool the viscose with brine with a temperature of 7 ° C. Viscosity

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age at a rate of 0.18 Pas for 1 s, i.e. 2% per I s of its original value. After reaching a viscosity of 22.5. 2.5 times the initial one, cooling is stopped, waiting for the viscose with high viscosity to pass through the filter through the filter and turn off the pump. Continue filtering viscose. The pressure drop is 0.1 MPa. The partition is cleaned.

With an increase in the rate of viscosity increase of more than 2% per I s of the initial pressure drop across the reactor, K. Voloshchuk

Compiled by N. Smirnova

Tehred N.Vonkalo Proofreader M. Maksimishinets

Order 2475/9 Circulation 663 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production 5 printing company, Uzhgorod, Projecto st., 4

306354

 Rodke exceeds the marginal performance of 0.8 MPa. An increase in viscosity of more than 2.5 times the original does not lead to an acceleration of the cleaning process. When the filtrate is fed into the countercurrent without increasing its viscosity, the degree of separation of the septum by differential pressure does not exceed 84%.

10 As a result of applying a filtrate with a viscosity to clean the filter of the baffle by the method of supplying the filtrate to the countercurrent, the degree of cleansing of the baffle increases.

Claims (3)

1. METHOD FOR CLEANING THE FILTER Baffle, including pressing the filtrate. Through a clogged baffle in the opposite direction of filtration, revealing that, in order to improve the quality of cleaning the baffle, increase the viscosity of the filtrate before punching. 2. The method according to π. 1, characterized in that the viscosity is increased 1.2-2.5 times from the initial viscosity at a speed of 0.3-2% for 1 s. 3. The method of pop. ^ characterized in that, the viscosity of the filtrate is increased by lowering its temperature. <5 ί230635