SU792614A1 - Electric-arc gas heater - Google Patents

Description

(54) ELECTRIC ARC GAS HEATER

one

The invention relates to electrical engineering, in particular, to a technique for producing low-temperature aqueous plasma and can be applied in the chemical, metallurgical industries, engineering and other industrial processes, in which a heated gas flow is required for carrying out the process.

The use of water plasma allows, in a number of cases, to radically change its effectiveness. This is due to the higher specific heat content of the water plasma and the filling up of the dissociated hydrogen and oxygen molecules, which are direct agents in chemical reactions, as compared with air, nitrogen, and other plasmas.

In addition, due to the absence of TOX1

The plasma jet component can be used as a tool for the destruction of rocks in the production of underground vents with difficult ventilation.

An electric-arc plasma water generator with magnetic stabilization of the electric arc 1 is known.

But this plasma torch cannot provide long-term uninterrupted operation, which is explained by large values of the erosion of the electrode material (on the order of 10 g / C).

Also known is an electric arc gas preheater containing coaxially and successively mounted rod cathodes, a ring of gas supplying protective gas, an interelectrode insert, a plasma-forming gas supply ring and an anode with cooling channels provided with a central through-hole of variable cross-section 15 inlet and outlet, of which is made cylindrical 2.

The disadvantage of this preheater is that it cannot effectively operate on water vapor.

20

The purpose of the invention is to increase the efficiency and efficiency of the heater.

To achieve this goal, the heater is equipped with a screen made of metal;

with a low thermal conductivity and an insert surface facing the anode, the inlet section of the anode is designed as a cone tapering towards the outlet and smoothly mating with it, and the cooling channels are located in the outlet section of the anode.

The use of a heat insulating insert and making the anode cooled only at the point of electric arc binding allows the walls of the inlet section of the anode and insert to be maintained at the vapor saturation temperature and, thus, to avoid condensation of steam on these surfaces. The need to increase the channel cross section in the initial part of the anode is explained as follows.

The presence of hot channel ducts in the initial part creates favorable conditions for shunting electric arc on it, which is completely undesirable because the area is slightly cooled. If the initial section of the channel is made of a larger diameter, then the electrical strength of the arc-wall gap increases substantially and breakdown in this area becomes impossible. The flow part of the initial section may be frustoconical, as shown in the drawing, or be cylindrical with the diameter of the larger base of the cone. At the same time, it is important that the transition from the initial section of the channel to the working cylindrical section be smooth and with an angle to the side of no more than 45 ° in order to avoid the formation of flow disturbances at the junction point also contributing to the shunting of D5 to the curve.

When these conditions are fulfilled, the anode attachment of the electric arc in the operating current range is detected at the output cylindrical intensely cooled part of the anode,

The drawing shows the proposed electro-gas gas preheater (plasma torch).

The plasma torch has a rod cathode 1, a swirl ring 2 for supplying protective gas, a water-cooled transelectrode insert 3, a heat insulating screen 4 mounted on the side of the insert facing the anode, a ring 5 for feeding the main gas and an anode 6 that has a variable opening output and having cooling only at the point of arc arc welding 7 on the cylindrical section 8.

Thermal insulation screen 4, rimmed from metal with low heat conductivity, closes the cold end of insert 3 and, having a temperature on the surface facing the anode above the temperature, we observe the vapor,

eliminates the possibility of condensation and steam in this place.

Insulators 9 and 10 are provided for electrically isolating the electrodes and the insert 3 from each other. Intensification of arc arc movement along the inner surface of the output electrode is performed using a magnetic field formed by the coil 11.

The start of the plasma torch is carried out in two stages.

At the first stage, an electric Arc is ignited by an oscillator when heated as a working gas is a temperature not lower than the saturated water vapor temperature of a non-condensing gas: air, nitrogen, etc., and then the plasma torch is heated for 2-3 minutes.

At the second stage, the projectile smooth transition to dry superheated water vapor and the subsequent work of the plasma torch on this working body is carried out.

The plasma torch has a high performance, lower specific erosion of the anode material than when operating in air, with sufficiently effective heating of water vapor and high stability of operation. The value of the specific heat content of the water plasma in it is 55.0 kJ /, which corresponds to a temperature on the order of 5000 ° with a thermal efficiency of 65-70% and a power consumption of 100 kW.

Claims (1)

Invention Formula An electric arc gas preheater containing coaxially and sequentially mounted rod cathode, protective gas feed ring, interelectrode insert, feed ring} of plasma-forming gas and an anode with cooling channels with a central through-hole of variable cross section made in two sections - input and output, the last of which is cylindrical, distinguished by the fact that, in order to increase the efficiency and efficiency of the heater, it is equipped with a screen made of metal with a low conductivities and mounted on the insert facing the anode surface, the anode inlet portion formed as a converging towards vyho; schomu and smoothly conjugated with it cone, and cooling channels arranged in the outlet portion of the anode.