CS242601B1 - A method of preparing the cleanliness of internal surfaces of steam-water circuits of power and chemical installations - Google Patents

Abstract

In the proposed method of preparing the cleanliness of internal surfaces, cleaning operations are included at the beginning of the production process, whereby these internal surfaces of steam circuits of energy and chemical equipment are treated to metallic cleanliness already from the metallurgical semi-finished products, either by mechanical, chemical or electrochemical means, and the required cleanliness of the surfaces is maintained or restored during the entire production process. The invention can be used in the assembly of all types of hot water and steam boilers, heat exchangers, steam generators, etc.

Description

The present invention relates to a process for preparing the cleanliness of the inner surfaces of steam-water circuits of ehergetic and chemical installations prior to initial commissioning.

For internal surfaces of steam and water circuits of power and chemical installations, metallic cleanliness is required prior to initial commissioning, which means that surfaces must not contain metal or non-metallic contaminants such as grease, dust, rust, scale and the like. In addition, the metallurgical methods for the purification and metal cleanliness of the internal surfaces of said devices are applied only after the installation of the device on site, and during the manufacturing process, the metallurgical semi-finished products are usually not conserved. adhering to the inner surface, which is difficult to remove, sometimes at all, after assembly. For the cleaning of the internal surfaces of said devices after installation, ee uses a method of cold and hot water flushing, chemical pickling and pressurized water steam flushing, but most often a combination of several or all of said methods. Treated inner surfaces are then protected by some of the wet or dry preservation methods until the equipment is put into operation. This method of preparation and sealing of the desired metallic cleanliness of the inner surfaces has a number of drawbacks. Assembly and commissioning of the equipment is extended by 1 to 3 months depending on the size and segmentation of the equipment. It is necessary to manufacture and install temporary single-purpose circuits including tanks, pumps and other auxiliary equipment, protection of valves and pumps of technological circuits. In most cases, it is not possible to reliably ensure that the internal surfaces of the equipment or accumulated insoluble substances are cleaned. It is also not possible to reliably and perfectly remove loose scale and other insoluble substances, especially in rugged systems and circuits and with high hydraulic resistance. These impurities accumulate in the hydraulically disadvantageous areas of the plant and are a frequent cause of plant failures. They arise considerable

242 601 demands on deficient chemicals, large quantities of chemically treated and raw water, consumption of steam and other energy There are great difficulties and costs in the construction of the above mentioned equipment connected with the release and disposal of considerable amounts of chemical degreasing and pickling solutions containing it cannot be freely discharged into watercourses or sewage networks. The costs of disposable chemicals, pumping, sludge disposal, etc. are increasing. The final effect of the desired degree of cleaning is not guaranteed due to incomplete removal of cleaning solutions and size after cleaning operations, especially in non-drainable parts of the apparatus. The possibility of additional contamination of the interior surfaces remains when dismantling the temporary circuits and routes.

The disadvantages mentioned above are eliminated by the process of preparing and ensuring the cleanliness of the inner surfaces of the steam and water circuits of the power and chemical devices according to the invention. SUMMARY OF THE INVENTION The object of the present invention is that internal surface cleaning operations on a metallic clean surface are incorporated at the beginning of the manufacturing process, the internal surfaces of the apparatus being treated to metallic purity from metallurgical blanks in a suitable mechanical, chemical or electrochemical manner. renews throughout the production oroces. The surfaces of the metallurgical semi-finished products and of the component parts for the manufacture of these equipment are treated to metal purity in the factory by a suitable mechanical, chemical or electrochemical method or a combination thereof and the required surface cleanliness is maintained or renewed throughout the manufacturing process and During the transport and storage period the treated internal surfaces of the equipment are protected by common methods of dry long-term preservation, the installation of the equipment is performed when the internal surfaces of the equipment are filled with inert gas, pressure or leak tests of the equipment during production and assembly are performed with inert liquid or inert gas. In the period from completion of assembly to start of operation the equipment is protected by filling with inert gas.

Metal surface cleanness can be achieved either by quality or by surface treatment of metallurgical semi-finished products (tubes, forgings, sheets, etc.),

242 601 furthermore mechanical working methods, such as blasting, chipping, chemical or electrochemical pickling and polishing · Introduction and use of these methods in production (

o Repeated use of internal surface cleaning operations in the factory also provides the possibility of automating these operations and making more efficient use of equipment or chemical solutions.

Avoid contact with the outside atmosphere, application of desiccants, inhibitors and inert gases to protect metallic clean surfaces during manufacturing, transport and storage · Leak and pressure tests can be performed with dry air, inert gases and inert liquids, such as alcohol.

The method of preparation of interior surface cleanliness according to the invention eliminates not only the disadvantages of the existing method of connection especially with chemical pickling, degreasing, piercing and blowing through the assembled devices, but mainly shortens the assembly time, eliminates production, assembly and dismantling costs. The process according to the invention allows the control of the cleanliness of the inner surfaces after each manufacturing operation * eliminates the deposition of insoluble substances, for example scale, in the adjustment as is normally the case with the prior art process.

A general example of the preparation of the metal-clean inner surfaces of the steam and water circuits of the power and chemical devices according to the invention is shown in the attached diagram.

In particular, the invention can be used in the construction and assembly of all kinds of hot water and steam boilers, heat exchangers, steam generators, chemical reactors and other energy and chemical machinery.

Claims (2)

SUBJECT OF THE INVENTION 242 601 1. A process for preparing the cleanliness of internal surfaces of steam and water circuits of power and chemical installations prior to initial commissioning, characterized in that cleaning operations are included at the beginning of the manufacturing process, wherein the internal surfaces of the equipment are treated to metallic purity electromechanically and the required surface cleanliness is maintained or renewed throughout the manufacturing process. Method according to claim 1, characterized in that the metal-clean interior surfaces of the assembly parts of steam-water circuits of power and chemical installations are protected during the manufacturing process by means of inter-operational protection, provided with long-term preservation means for transport and storage. parts and components with inert gas and pressure and leakage tests are carried out with an inert liquid or gas, and the interior spaces are filled with inert gas from the end of assembly to the beginning of delivery.