阅读说明：本技术 在超纯蒸汽生产中除去痕量杂质的方法 (Method for removing trace impurities in production of ultrapure steam ) 是由 J·L·斯通 于 2018-09-12 设计创作，主要内容包括：一种从具有痕量杂质的纯化水中产生没有痕量杂质的超纯蒸汽的方法,包括：将具有痕量杂质的纯化水导入蒸汽发生器的腔室的进水套管中,腔室包括由熔融石英制成的腔室外壁和腔室内壁以及将腔室分隔成下腔室区和上腔室区的加热多孔熔融石英件。将多孔熔融石英件加热至蒸汽形成温度并且将从下腔室导引通过熔融石英件的含杂质的纯化水转化成具有减少的痕量杂质的蒸汽。从上腔室将蒸汽递送至蒸汽饱和壳体。(a method of producing an ultrapure vapor free of trace impurities from purified water having trace impurities, comprising: purified water with trace impurities is introduced into a water inlet sleeve of a chamber of a steam generator, the chamber comprising an outer chamber wall and an inner chamber wall made of fused silica and a heated porous fused silica piece separating the chamber into a lower chamber region and an upper chamber region. The porous fused silica article is heated to a vapor forming temperature and purified water containing impurities directed from the lower chamber through the fused silica article is converted to a vapor having reduced trace impurities. Vapor is delivered from the upper chamber to the vapor saturation housing.)

1. A method of producing a vapor from which trace impurities have been removed, comprising:

Introducing purified water having trace impurities into a water inlet sleeve of a chamber of a steam generator, the chamber comprising an inner chamber wall and an outer chamber wall made of fused quartz and a porous fused quartz piece dividing the chamber into a lower chamber region and an upper chamber region;

Heating the porous fused silica article to a vapor forming temperature;

Directing the purified water through the heated piece of porous fused silica to generate steam from the purified water, wherein the generated steam has been depleted of trace impurities; and

The resulting vapor with the trace impurities removed is directed to a vapor saturation shell.

2. the method as set forth in claim 1, wherein the trace impurities removed are sodium and potassium.

3. The apparatus of claim 1, wherein the porous fused silica article is sintered glass.

4. the apparatus of claim 1, wherein directing water into the water inlet sleeve comprises continuously supplying water to the water injector.

5. The apparatus of claim 1, wherein the chamber is cylindrical and the porous fused silica material is in the form of a disk.

6. A method of removing impurities from purified water for ultrapure steam production, comprising:

Providing a steam generator comprising:

A chamber with a purified water input sleeve, a steam exhaust sleeve and a plenum chamber therebetween, an inner chamber wall and an outer chamber wall made of fused silica, and a heated porous fused silica piece separating the plenum chamber into a lower chamber region and an upper chamber region;

an electric heating coil surrounding a portion of the chamber outer wall of the fused silica of the plenum and transferring heat to the porous fused silica piece;

a ceramic sheath surrounding the electrical heating coil and the outer wall of the chamber of fused silica in a thermally insulating manner;

A nozzle for supplying purified water through the chamber water inlet sleeve into the heated porous fused silica article;

a saturated shell;

An aperture connected to the chamber steam exhaust sleeve to receive generated steam into the saturated shell; and

a vapor delivery port;

injecting purified water having trace impurities into a lower chamber region of a steam generator chamber;

Heating the porous fused silica article to a vapor forming temperature;

Introducing the injected purified water into the heated porous fused silica piece of the lower chamber region and to the upper chamber region, thereby converting the purified water into steam through the porous fused silica piece, the steam produced having removed trace impurities; and

steam is directed into the steam saturated shell from the upper chamber region of the first chamber.

7. The method as set forth in claim 6, wherein the trace impurities removed are sodium and potassium.

8. the method of claim 6, wherein the chamber further comprises a fused silica tube surrounding the coil and separating the coil from the ceramic sheath, thereby reducing heat transfer from the coil to the sheath.

Technical Field

The present invention relates to steam generation and, in particular, to a method for removing trace impurities in the production of ultrapure steam.

Background

A steam generator for producing ultra-pure steam is disclosed in U.S. patent No. 9,631,807 assigned to University Research Glassware Corporation (University Research glass Corporation) by Jonathan l.stone. It describes sintered glass made of a glass material inert to water and steam, such as sintered borosilicate (sometimes sold under the trademark Pyrex), for converting injected pure water into pure steam on opposite sides of a sintered refractory glass sheet in a chamber. A sintered glass piece or plate divides a plenum formed within the chamber into a lower chamber region and an upper chamber region. The nozzles supply purified water to the sintered glass piece which is heated by an electric heating coil surrounding the glass piece on the outside of the chamber. It is disclosed that purified water migrates upward through the gaps in the sintered glass sheet, evaporating as the temperature of the glass piece increases. The evaporated water moves into the upper chamber area where it is directed to the chamber's vapor vent sleeve, which is connected to the saturated shell. The pressurized air forms an ultra-pure vapor jet in the vapor evacuation sleeve toward the vapor delivery port of the saturated shell. All parts that come into contact with water and steam are made of high temperature glass, essentially chemically inert material, allowing pure water to be fed through a water nozzle to produce pure steam free of particles and impurities.

However, the steam generator of the' 807 patent is good at producing steam, but has the problem that the produced steam is not as pure as needed or desired, at least with trace amounts of sodium and potassium impurities found in the purified water and the produced steam.

there is a need for a method and apparatus for removing trace impurities in the production of ultrapure steam for scientific or medical laboratory applications.

Disclosure of Invention

The present invention is a process for removing trace impurities in the production of ultrapure steam. The method of the present invention employs a specific configuration other than the pre-conceived configuration of the steam chamber of the steam generator of U.S. patent No. 9,631,807.

In the method of the present invention, purified or deionized water is injected into a chamber of a steam generator having a special configuration using fused silica. The chamber used in the method of the present invention comprises a sintered fused silica piece or plate that divides a plenum formed in the chamber into a lower chamber region and an upper chamber region. In addition, the chamber also includes an inner wall made of fused silica for contacting the purified water and steam and an outer wall made of fused silica adjacent to the electric heating coil or the nichrome wire. In the method of the invention, a nozzle feeds purified water, typically with trace impurities including sodium and potassium, into a fused silica chamber having a piece of sintered fused silica for producing ultra-pure vapor. In this method, the piece of sintered fused silica is heated by an electric heating coil surrounding the piece of fused silica on the outside of the chamber. The purified water moves upward through the voids in the sintered fused silica plate and evaporates due to the elevated temperature of the fused silica piece. At this time, the evaporated water with reduced or removed trace impurities enters the upper chamber region where it is guided to the steam outlet sleeve connected to the chamber of the saturated shell. The saturated shell has pressurized air blown into the shell through a steam exit sleeve where the gas becomes saturated by condensing the steam and prevents condensation on the wall surfaces. The pressurized air forms a steam jet towards the steam delivery opening of the saturated shell. The resulting vapor jet comprises an ultrapure vapor having reduced or completely removed trace impurities including sodium and potassium. The amount of trace impurities of sodium and potassium in the chamber purified water and the amount of trace impurities of sodium and potassium in the chamber generated steam are less than the amount of trace impurities of sodium and potassium found in the injected purified water.

it is a surprising discovery of the present invention that the use of sintered fused silica plates coupled to inner and outer fused silica chambers can convert injected pure water with trace impurities into decontaminated water and ultrapure decontaminated vapor on opposite sides of the sintered fused silica plates. This finding shows that sodium and potassium impurities are present in the ultra-pure steam and chamber water by an order of magnitude smaller with the method of the present invention than with the chamber water and the ultra-pure generated steam of the prior art. The prior art steam generators use any configuration of high temperature and contaminant free glass materials, such as borosilicate. In contrast, no sintered fused silica plates in a chamber with borosilicate inner walls were found to reduce sodium and potassium impurities. The combination of sintered fused silica plates and the inner and outer walls of the fused silica chamber are disclosed in the method of the present invention.

it was previously expected that all of the disclosed high temperature, water and steam inert glass materials used to make sintered glass sheets and internal chambers would produce the same or similar trace impurity results for the ultra pure steam produced. However, this is not the case. Although the previously disclosed glass materials are made of materials that are considered water and steam inert, such as borosilicate, and the water fed into the sintered borosilicate glass piece is purified, the purified water and the generated steam disadvantageously contain trace amounts of sodium and potassium.

Drawings

FIG. 1 is a front view of a steam generator having a particular steam chamber configuration for use in the method of the present invention.

Detailed Description

A method of removing trace impurities (i.e., sodium and potassium) from deionized or purified water and ultrapure steam produced from deionized water includes injecting purified water, typically having trace impurities (including sodium and potassium), into a specially configured steam chamber of the steam generator 11 of fig. 1. The construction of the steam chamber of the steam generator 11 comprises an outer fused silica wall 19, an inner fused silica wall 21 and a sintered fused silica plate/piece 23 which engages water and steam in the chamber. The combination of fused silica walls and sintered fused silica pieces is unique in that it is less likely to introduce impurities into the steam being generated than the prior disclosed steam chamber configurations, materials and material combinations, and in fact removes or reduces the trace sodium and potassium impurities found in the injected deionized or purified water.

Referring to fig. 1, the steam generator 11 has water and steam contacting parts made of fused silica. It can be seen that the fused silica vapor chamber 11 is seen as a cylinder with an axis of symmetry and an axial water inlet sleeve 13 at the lower end and an axial vapor outlet sleeve 15 at the upper end. Fused silica with a wall thickness of 1.5 mm may be used. Each sleeve may be shaped as a luer connection, i.e. with a slight taper to accommodate the tube by a press fit. The chamber has a cylindrical fused silica outer chamber wall 19 and a cylindrical fused silica inner chamber wall 21.

The central portion of the chamber 11 is a plenum chamber 17 that is divided by a sintered fused silica plate 23 into a lower chamber region 25 and an upper chamber region 27. The sintered fused silica plate 23 is disc-shaped or plate-shaped and is molded across the inner circumference of the chamber 11, blocking fluid communication from the lower chamber region to the upper chamber region except as described below. The fused silica piece 23 is not fused to the chamber but wedged between the chamber inner wall stops for mechanical support. The member has inherent micro-pores from the sintering process and sufficient pore density to allow water vapor to pass from the side facing the lower chamber up through the fused silica piece 23 to the side facing the upper chamber. The pores are between 170 and 200 microns. The fused silica frit has a large surface area to allow it to retain more heat and operate as a heat sink.

the electrical heating coil 29 surrounds the chamber outer wall 19 adjacent the sintered fused silica article 23, adjacent the circumferential edge of the fused silica article and in close heat transfer relationship. The heating coil is made of a spiral coil of nichrome wire, similar to the wire in an electric oven. The wire with high electrical resistance has spaced coils and glows red thermally when a DC current (direct current) is passed through and transfers constant heat to the frit by conducting and radiating heat to the nearby piece of sintered fused silica 23. Heat flows radially inward from the heater coil to the center of the fused silica piece. Water injected into the bore of the sintered fused silica piece tends to evaporate and communicate with the upper chamber region 27 through the gap of the fused silica piece. The amount of sodium and potassium trace impurities in the evaporated water is significantly reduced. The energy input via the heater coil is about 2400 joules/ml of water. The wire may be wrapped more tightly around the area of the fused silica frit 23 to ensure that sufficient heat is supplied to sufficiently heat the frit.

In one example, a fused silica tube is mounted throughout on a nickel chromium wire. The inner diameter of the tube is slightly larger than the outer diameter of the fused silica chamber around which the wire is wound. This results in a small gap between the heating wire and the tube, preventing the wire from contacting the tube 36. The small amount of clearance prevents heat from the wire from conducting to the ceramic sleeve rather than to the chamber. Without the tube, the heat is more likely to conduct to the ceramic sleeve, wherein in some cases the ceramic sleeve may heat the saturated enclosure 41 so that some steam is also generated therein. Preferably, steam should only be delivered to the saturation chamber but not generate steam therein.

A ceramic sheath 31 made of castable or moldable quartz ceramic surrounds the chamber 11 to provide external thermal insulation and to retain heat inside the steam generator. The ceramic sheath has a cylindrical dead space 33, i.e., a gas void, located radially outwardly of the heating coil 29 and axially coextensive therewith to partially block heat transfer to the ceramic sheath by conduction. The radial extent of the dead zone is only 1 mm or perhaps a few mm, but the dead zone directs heat to the molten quartz piece 23, allowing the outside of a ceramic sheath of a few centimeters thick to be cool enough to grip the outside of the sheath from injury. A ceramic sheath is applied to the outside of the entire vapor chamber to provide insulation. The ceramic jacket has a high combustion temperature and is durable. It is safer than other types of insulation such as fiberglass tape or fabric. Unlike fiberglass tape or fabric which is exposed to the nichrome wire, the ceramic sheath is, for example, a permanent, non-removable coating. Fiberglass tapes or fabrics do not provide sufficient insulation and the surfaces to which they are applied can still become very hot and present a potential fire hazard.

The water jet nozzle 35 is a precision jet pump having a tubular water inlet tube 51 and a water jet 55 extending from the nozzle into the water inlet sleeve 13 toward the piece of fused silica 23. The water jet 55 will traverse the sintered fused silica piece 23 in a hemispherical shape with the shortest water path being forward and the longer path being partially radial. The feed water flow rate was about 12.8 ml/hr. Note that the radial zones are hotter due to the proximity to the heating coil 29. Higher temperatures in the radially outward region of the fused silica piece favor greater evaporation, but longer flow paths reduce the amount of water. On the other hand, the shorter forward path is located in the cooler region of the molten quartz piece, so the evaporation rate is lower, but the short flow path is advantageous for increasing the amount of water. The end result is that the thickness of the fused silica piece can be selected for a particular chamber that has a substantially uniform vaporization on the upper surface of the barrier. The water flow into the nozzle 35 is regulated by the stepping motor 38 so that the water continuously flows toward the fused silica member 23. No water layer formed near the fused silica article. There may be a risk of explosive boiling. Excess water flows out of the water inlet sleeve 13. Calibration may determine the inlet water flow rate to achieve a desired continuous steam output through the steam discharge sleeve 15.

The steam in the steam discharge jacket 15 enters a steam discharge pipe 37 having an orifice 39 extending into a glass saturated enclosure 41. The saturated enclosure may be mechanically supported by the steam chamber 11 by support arms 53 and has air input ports 43 in which air flow 45 is directed by the flow rate and pressure established by the fan. The airflow rate is sufficient to allow the steam to condense in the air but prevents the steam from condensing on surfaces within the saturated enclosure, while the airflow is preferably saturated with steam. The typical ratio of gas flow to injected water volume is 14, 063 ml gas to 1 ml water. The orifice 39 is shaped and positioned in the air flow so that the low pressure draws the vapor out of the vapor discharge tube 37 by the bernoulli effect, avoiding condensation at the tip of the discharge tube. The vapor in the gas stream is delivered from a vapor delivery port 49, which may be shaped as a luer connection. The vapor delivery is represented by arrow a.

the present invention envisions that the influent water flow rate can be determined by calibrating the continuous flow of water input and steam output. All parts that contact the water and steam in the chamber, i.e. the frit and the inner walls of the chamber, are made of fused silica, while all other parts that are in contact with the water and steam are made of high temperature glass, such as pyrex glass, so that pure water, which usually has traces of impurities therein, is fed through the water nozzles 35 to obtain pure steam that is free of particles and in particular free of sodium and potassium or traces of impurities.