WO1998045659A1 - Mechanical surface treatment of chemical equipment and instrumentation to clean them from metal-containing sludge belonging to the platinum group - Google Patents

Abstract

The present invention relates to mechanical surface treatment to be applied to chemical equipment and instrumentation to clean them from sludge containing metals from the platinum group and can be used in laboratories which use them as catalysts. According to the method, the mechanical cleaning is made using a cutting instrument, the primary motion of which is the return movement and/or the movement on the treated surface, the cutting speed being selected in a range of 0.015 to 35 m/s for a cutting force of 0.05 to 2800 n, while the momentum given to the instrument on the treated surface is in a range of 3 x 10-5 to 9 m/s. The inventive method enables a very efficient cleaning of surfaces from platinum-containing deposits and improved extraction of precious metals.

Description

\УΟ 98/45659

SPΟСΟБ ΜΕΧΑΗICHΕSΚΟY ΟCHISΤKI

PΟΒΕΡΧΗΟSΤΕY ΧIΜICHΕΚΟY ΑPPΑΡΑΤUΡY ΟΤ

SLΑΜΟΒ, SΟDΕΡΑSHHIΧ ΜΕΤΑLLLY PLΑΤIΗΟΒΟY

GROUPS.

Field of technology.

The present invention concerns methods of mechanical purification of chemical atoms sludge containing platinum gas metals (PGG), and can be used in the chemical and metallurgical industries V installations using catalysts made of platinum gas metals, for example, in installations for the production of nitrogen, hydrocyanic acid and hydroxylamine sulfate, as well as for the purification of heat exchangers or τρubοπροοτοτ deposits that deteriorate the performance characteristics of devices.

Technical level. During operation, the internal surfaces of pipes, devices and installations are contaminated with various deposits, including platinum ones. In the production of plants using them as catalysts due to the condensation of vapors and their oxides. As a result of the operation of aggregators, there is a lack of concentration of nitric acid with power About 1,200 thousand rubles per day (based on 100% acid) for five years only on tubular rollers Father God, up to 50 kg of platinum-containing elements can settle in the boiler and economizer, in addition to rust and scale, which also accumulates on the inner walls of the apparatus, traps the smallest particles of sludge containing platinum-containing elements, which are separated from the catalysts in \УΟ 98/45659 ₂

the process of their operation [M.M. Karavaev et al. "Ammonia Oxidation Catalysts" Moscow, "Khimiya", 1983].

These deposits, in addition to the fact that they can contain large quantities of precious metals, degrade operational

5 characteristics of the devices, and various methods and devices are used to remove them.

There are known methods for cleaning apapatata, for example, the deposition of salts, which can can also be used for cleaning sludge containing LPG.

10 About the singing method [Zυ car certificate 213088,

[P280 3/08, 1968] a brush in the form of a ruff is used as a cutting tool with the main cutting movement being a rolling and reciprocating-advancing movement relative to the surface being processed.

15 In this way [δυ car certificate 671873,

[B08B 1/04, P28C 3/08, 1979] cylindrical springs with teeth on their outer surface are used as a cutting tool. The springs are fastened in a frame. The main cutting movement in this method is

20 rotary movement of the frame with springs, as well as their screw movement over the surface being processed. The disadvantage of the above methods is the difficulty of introducing the instrument into the deposit surface and the lack of any quantitative data on the cutting parameters, which does not

25 allows you to effectively name it for the mechanical cleaning of waste materials, such as sludge, containing MPG.

The closest thing to the proposed technical solution in terms of the totality of characteristics is the method of mechanical cleaning chemical disturbances, 98/45659 ₃

for example, from sludges containing MPG, including the treatment of these surfaces with a cutting tool (a special cleaning head), in which the main cutting motion is a rotating motion and/or a movement along the

5 processed information, i.e. equidistant about her [δυ, auto certificate 1812418, No. 280 3/08, 1993]. The disadvantage of this method is the type in which voluntary cutting movements are used on the workpiece The message of any form is also the existence of a

10 or quantitative data on cutting parameters and their relationships, which does not allow effective use of this method for cleaning the surface of chemical equipment containing, for example, sludge with MPG.

Revealing the essence of the invention of genius.

15 The main problem, which the present invention is aimed at solving, is to increase the efficiency of mechanical cleaning of the surfaces of chemical equipment and to increase the mass of sludge containing MPG obtained as a result of mechanical cleaning.

20 This problem is solved by the proposed method of mechanical cleaning of the surfaces of chemical equipment from sludge containing MPG, including the treatment of these surfaces with a cutting tool in which the main cutting motion is a rotating motion and/or

25 movement along the surface being processed, with the cutting speed selected in the range of 0.015 - 35 m/s at a cutting force of 0.05 to 2800 N. An additional distinguishing feature of the method is that in the case where the main cutting movement is a swinging movement, the tool ννθ 98/45659 ₄

They provide feed rate over the processed surface in the range of 3 x 10-5 - 35 m/s. The following devices are used as cutting tools in the proposed method: brush, cutter, burr, reamer, countersink, etc.

5 Until now, the processing conditions proposed in this method were not known: the ranges of cutting speed and force, the implementation of which significantly increases the efficiency of mechanical cleaning of the surfaces of chemical equipment due to an increase of 23-26% of the mass containing

10 ΜPG of sludge produced as a result of mechanical cleaning (see types Ν°Ν9 1-7 in the table).

Examples of the invention. The invention is illustrated by examples N2N2 1-7. In this case, examples N2N2 1-3 and 6, 7 fully cover

15 proposed ranges of cutting parameters, and in examples Nos. 4, 9, 5 the quantitative values of cutting parameters are taken outside the proposed ranges of these parameters.

Industrial testing of methods for mechanical purification of waste chemicals and chemical atomization of sludge containing

20 MPG are carried out on a G-335BP type waste heat boiler of nitrous gases formed as a result of the ammonia oxidation reaction on platinum oxide catalyst networks in a reactor located directly in front of the boiler. This waste heat boiler is used in a non-concentrated waste heat unit

25 nitric acid plants with a single pressure of 0.716 MPa and a capacity of 355 t H2O3/day. The boiler has a worn-out body and contains a water dispenser in the form of a shell-tube heat exchanger, containing 480 pits 50 x 3 mm long about 6 m from steel 20, with a total heat exchange rate of 330 mg UUO 98/45659 ₅

In addition, it has a heat exchanger with a heat transfer capacity of 5.7 m2 of 50 x 3 m of 15ΧΜ steel, curved in the form of ellipsoids. The ends of the pipes in the input and output chambers. The poisonous gas containing ΜNG sludge is toxic

5 in the intertubal phase of the heat sink and in the tubular phase of the vaporizer, and this is nitrous gas At the same time it comes into contact with the body of the cauldron. In connection with this, the sludge containing ΜNG is referred to external sources, internal the news of the scavenger's teeth,

10 internal communication of the fire department. During the tests, a waste heat recovery unit with a 5-year history of operation was used. To obtain comparable results in the application Ν2Ν2 1 - 5 mechanical cleaning two-wheeled 50 liters destroyer, placed geometically similar

15 relative to the central axis of the intermediate tube heat exchanger of the boiler. In this way, the tube sections were selected so that each of the sections had the same amount of sludge containing MGP on the inner surfaces of the tubes.

Β Βπρρρχ Ν°Ν9 6.7 mechanically cleaned two-wheeled

20 respectively, the outer surfaces of the superheater tubes and the inner surface of the cap liner. The surfaces of the superheater tubes and the cap liner had complex shapes. The main test results are given in the table. From the comparison of the results of examples 9N 1-3 (in the proposed

25 ranges of cutting parameters) with example No. 4 (below the limits of the proposed cutting parameters) it is evident that in examples No. 9 1-3 the amount of the obtained mass of sludge containing MPG is 23 - 26% higher than in example 4. \νθ 98/45659 _b

In this way, the proposed invention for the purification of chemical atomizers from deposits, containing platinoids, any operating tool, allows you to effectively notify the processing of contaminated

5 surfaces with an increased degree of extraction of platinum group metals.

Industrial applicability. The proposed invention is intended primarily for cleaning the internal surfaces

10 apapate containing deposits of platinoid compounds used as catalyses, but can also be used in various technological processes where there are such provisions, etc. The set parameters of cutting speed and cutting force allow the most effective

15 Use a cutting tool.

20

5 Table

RESULTS OF TESTING.

Claims

\ΥΟ 98/45659 8 ΦΟΡΜULΑ IZΟΡΕΤΕΗIYA 1. Method of mechanical cleaning of sludge containing platinum metals lips, 5 including the processing of these surfaces with a cutting tool, the main cutting movement of which is a rotating movement and/or a movement along the surface being processed, characterized in that the cutting speed is selected in the range of 0.015 - 35 m/s with a cutting force of 0.05 10 to 2800 N. 2. Method 1, characterized in that in the case where the main cutting movement is a rotary movement, the tool is given a feed rate over the workpiece surface in the range of 3.10-5 - 9 m/s. 15 0 5