DD140582A1 - METHOD FOR MELKING FIXED SUBSTITUTES OF HEAT TRANSFER FLUIDS - Google Patents

Abstract

The invention relates to a method for melting solid Precipitation of heat transfer surfaces and relates in particular in the field of cryogenic technology. Goal of' Invention is the melting of solid precipitates of Heat transfer surfaces, wherein the corresponding heat exchanger of a gas and / or vapor medium flows around, too develop, with little equipment and energy expenditure the continuous and flexible operation of facilities allowed, in where such heat exchangers are installed. It is the task without separation of the heat exchanger to be melted from the process a continuous operation of the system without impairment to secure their performance parameters. According to the invention, the heat exchanger a small heat exchanger upstream, the same from a gaseous and / or vaporous medium, but during the Abschmelzvorganges is surrounded by liquid. The warmed up here Medium then flows through the divided into sections heat exchanger Sectionwise with at least twice but not more than six times Mass flow. The invention comes with stationary liquid gas tanks © Oii «·. I »will be used. , 8 pages

Description

209 60 6

TITLE OF THE INVENTION

Method for melting solid precipitates of heat transfer surfaces

FIELD OF THE INVENTION

The invention relates to a method for melting solid precipitates of heat transfer surfaces, wherein the corresponding heat exchanger is flowed around by a gaseous and / or vaporous medium and it is used for evaporation and / or heating of media, in particular low-boiling liquefied gases.

CHARACTERISTICS OF BEAUTIFUL TECHNICAL SOLUTIONS

There are several known methods of removing solid precipitates from heat transfer surfaces based on the supply of heat or solvents.

It is customary to operate two parallel heat exchangers with the same power alternately by only one heat exchanger works, while

-8.ÜFZ.1975 * 755516

-a-

209 606

the other at this time by the surrounding air itself, by heated gas, by heating steam or by sprinkling with warmed water is molten (z., DD-PS No. 18730).

The disadvantage of this method, the arrangement of two heat exchangers of equal size with the associated space requirements, the cost of required changeover valves including the triggering measuring and control technology and various devices such as blowers, electric heaters, etc. Furthermore, it is known that by radiation and / or electric heater heating Heat for melting solid precipitates, eg. As ice, fed c /. B. DD-PS-No. 103313) The application of these methods is difficult, since usually complicated finned tube heat exchangers are to be heated, the construction of which requires considerable technical effort for the execution of the electrical heating, sometimes even protected, combined with a time-consuming heating phase and uneven heat distribution in addition, a method in which the medium to be vaporized or heated is heated by electric heating directly to a temperature suitable for melting the solid precipitates (eg DD-PS-No * 103313, DE-OS-WR 2616498 ). The disadvantage here is that in continuous operation is also working with two parallel heat exchangers, in addition to the resulting Kachteilen still evacuation container, flameproof design and additional safety features are added *

-5- 209 60 6

Another known method is carried out so that a solvent, z · B. · Glycol, is sprayed onto the solid precipitates and this dissolves the precipitates from the heat transfer surfaces (DD-PS-No. 54020) · This method requires pumping systems, spray and It is unsuitable for low-boiling liquids such as oxygen.

OBJECTIVE OF THE BRFINDUIiG

The aim of the invention is to develop a method for melting solid precipitates of heat transfer surfaces, wherein the corresponding heat exchanger is flowed around by a gas and / or vapor medium, which allows the continuous and flexible operation of plants with low equipment and energy costs in which such heat exchangers are installed.

Essence of the invention

The invention is based on the object to design the method so that without separation of the heat exchanger to be melted from a process, a continuous operation of the system is secured without affecting their performance parameters ·

This object is achieved in that the heat exchanger is preceded by a small heat exchanger, which is also of a gas and / or

vaporous medium, preferably ambient air, flows around it, but in the melting-off period is heated with liquid and in this case the medium flowing through it is heated to the temperature required for the melting process. The entire medium is then transferred to the solid-precipitated heat exchangers divided into sections; wherein the length of the heat transfer tube connected in series within a section is in the range of 100 to 2000 times the internal diameter of the pipe, supplied in sections with at least twice but not more than six times the mass flow and frees the corresponding heat transfer surfaces from their solid precipitates.

Embodiment

The method according to the invention will be explained in more detail in one embodiment of the cryogenic technique.

For the continuous supply of a consumer with gaseous, pressurized oxygen, liquid oxygen is withdrawn from a stationary tank. This liquid passes into the device consisting of two heat exchangers surrounded by ambient air flow in succession for evaporation and heating. In operation, both form on the heat transfer surfaces. Heat exchanger Frost and ice deposits, which increase at different rates depending on the weather conditions and require a necessary melting process ·

-ff-

209 60 6

The Abschmelzprozeß is initiated by the smaller, first acted upon by oxygen heat exchanger is flooded and heated by water, the oxygen receives the necessary for the Abschmelzprozeß the downstream larger heat exchanger temperature · The latter heat exchanger has vertically arranged finned tubes, which are spread over three sections · The length of the finned tubes within a section is 500 times the inside diameter of the tube. • The total quantity of acidified material is passed through a section of the heat exchanger by closing two sections, so that the corresponding finned tubes now have three times the amount of oxygen compared to the hormone operation during the melting process The heat input for evaporation and heating of the oxygen up to the temperature required for melting takes place during the entire melting process via the heat exchanger located in the water · The necessary water bath temperature is ensured by steam heating · It can be supplied also electrical energy or warm water · As soon as the first section is defrosted, on the second and after its defrosting on the third section is switched, whereby always only With the removal of the solid precipitates from the heat transfer surface of the third section of the heat exchanger the Abschmelzprozeß is completed and the first and second section is switched on again ·

209 60 6

The steam heating is set, the water drained and thus both heat exchangers start to work together again in normal operation · The method has the advantage that even during the Abschmelzprozesses the evaporation and / or heating of the medium continues to equip, without that. This is worth mentioning "There is no significant increase in the material intake, since the upstream heat exchanger is made very small and allows by its own performance, a reduction in the size of the heat exchanger to be melted.

The method further has the advantage that, if necessary, approximately doubling the heat transfer efficiency with good controllability up to this value over a longer time is possible. By reducing the number and duration of the melting processes and improving the heat transfer, energy is saved »

Claims (1)

209 60 BRFINDIMGSAISPRUCH Method for melting solid precipitates of heat transfer surfaces, wherein the corresponding heat exchanger flows around a gaseous and / or vaporous medium and is used for evaporation and / or heating of media, in particular low-boiling liquefied gases
in that it is preceded by a small heat exchanger, which is also preceded by a gas and / or
However, during the Abschmelzvorganges flows around liquid and in this case the medium flowing through it is heated to the temperature required for the Abschmelzvorgang, then the entire medium the solid precipitated and divided into sections' heat exchanger, the length of which within a Section of series-connected heat transfer tubes in the range of 100 to 2000 times the Rohrinnendurchrnrnersr, sectioned with at least twice but not more than six times the mass flow applied ·