Energy-saving steam condenser at top of hot water tank in vinyl chloride production

Abstract

The utility model discloses an energy-saving steam condenser at the top of a hot water tank in vinyl chloride production, which belongs to the technical field of vinyl chloride production, solves the problem of waste of hot water tank resources in vinyl chloride production, and comprises a hot water tank, a steam condenser is arranged at the top of the hot water tank, and a steam blow-down pipe is connected onto the steam condenser; the bottom of the hot water tank is respectively connected with a conversion hot water pump and a rectification hot water pump through hot water pump inlet pipes, the conversion hot water pump is sequentially connected with a hot water cooler and a converter through a conversion hot water feeding pipe, and the converter is connected with the hot water tank through a conversion hot water return pipe; the rectification hot water pump is connected with a reboiler through a rectification hot water feeding pipe, the reboiler is communicated with a rectification tower, and the reboiler is sequentially connected with a steam condenser and a hot water tank through a rectification hot water return pipe. The steam is cooled by utilizing the temperature difference between the steam and the hot water, so that the discharge of the steam is avoided, the use amount of converted desalted water is saved, and meanwhile, the cooling capacity is saved by using the hot water for cooling.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of vinyl chloride production, and particularly relates to an energy-saving steam condenser at the top of a hot water tank in vinyl chloride production. BACKGROUND

[0002] In the production of polyvinyl chloride by the calcium carbide method, a hot water tank is arranged in a vinyl chloride synthesis device, and a hot water circulating system is established by a conversion hot water pump and a rectification hot water pump, and the main purposes are as follows.

[0003] First, hot water is usually used as a heat source in the vinyl chloride converter in the early stage of the reaction, heat exchange is carried out with the reaction material, and the heat required for the reaction of hydrogen chloride and acetylene is provided, a hot water circulating system is usually arranged in the converter, hot water is heated by steam from the hot water tank and then sent to the converter, and in the later stage of the reaction, when the reaction temperature of the converter reaches 110 DEG C-180 DEG C, the temperature of the hot water is increased after absorbing the heat released in the reaction, and a circulating water cooler is usually arranged at the outlet of the conversion hot water pump to cool the hot water and then send it to the converter for recycling.

[0004] Second, in the rectification process of vinyl chloride, hot water is usually used as a heat exchange medium, and heat is provided for the rectification tower by indirect heating. The hot water flows through the reboiler of the rectification tower or the heater at the bottom of the tower, heat is transferred to the material at the bottom of the tower, the light components in the material are evaporated, and thus rectification separation is realized. In the rectification operation process, the hot water recovery temperature is decreased.

[0005] From the above changes in the temperature of the hot water circulating system, it can be seen that the temperature of the conversion hot water is increased in the circulating process, and the temperature of the rectification hot water is decreased in the system circulating process. In the usually designed and matched vinyl chloride production device, the amount of conversion water is much larger than the amount of rectification water, and thus the heat brought by the conversion backwater can cause the temperature of the hot water tank to be too high. When the temperature of the hot water in the hot water tank is greater than or equal to 96 DEG C, the amount of steam discharged from the top of the hot water tank is large, and a large amount of steam is discharged from the top of the hot water tank. The following problems exist. The hot water tank is usually supplemented with industrial desalted water. Since the cost of industrial desalted water is high, the consumption of desalted water is increased due to the large amount of steam discharge, energy is wasted, and the production cost of vinyl chloride is ultimately increased. At the same time, a large amount of steam is discharged on the device site, and a large amount of condensate water is generated on the operation site. Long-term discharge can cause rust on the equipment and facilities on the site, especially the rust on some safety protection devices on the site, and there is a safety hazard. UTILITY MODEL CONTENTS

[0006] The utility model aims to provide a kind of energy-saving steam condenser at the top of hot water tank in vinyl chloride production, to solve the problem of resource waste in the hot water tank in vinyl chloride production.

[0007] The utility model discloses a technical scheme: a steam condenser of energy -conserving type at hot water tank top in vinyl chloride production, including hot water tank, be equipped with steam condenser at hot water tank top, be connected with steam condenser through setting up steam pipe on hot water tank, steam condenser is connected with steam venting pipe, the bottom of hot water tank is connected with conversion hot water pump and rectification hot water pump respectively through hot water pump import pipe, and conversion hot water pump is connected with hot water cooler and converter in proper order through conversion hot water upper water pipe, and converter is connected with hot water tank through conversion hot water return pipe, and rectification hot water pump is connected with reboiler through rectification hot water upper water pipe, and reboiler is connected with rectification tower, and reboiler is connected with steam condenser and hot water tank in proper order through rectification hot water return pipe.

[0008] As a further improvement of the utility model, the hot water cooler is connected with a circulating water pipe.

[0009] As a further improvement of the utility model, the hot water cooler, the converter, the reboiler and the steam condenser are shell-and-tube heat exchangers.

[0010] As a further improvement of the utility model, the temperature of the hot water before starting the hot water tank is greater than or equal to 85℃.

[0011] As a further improvement of the utility model, the outlet temperature of the hot water cooler is controlled to be 90±1℃.

[0012] As a further improvement of the utility model, the temperature of the rectification hot water return in the rectification hot water return pipe is 65℃±5℃.

[0013] The utility model has the advantages that according to the different effects of the converter using hot water to remove heat and the rectification tower using hot water to heat in the process production, the temperature of the conversion hot water return is increased, and the temperature of the rectification hot water return is decreased, and the conversion water consumption is much greater than the rectification water consumption in the commonly designed matching vinyl chloride production device, so that the heat brought by the conversion return water makes the temperature of the hot water tank too high, and steam is discharged at the top of the hot water tank. The utility model sets the steam condenser at the top of the hot water tank, uses the rectification return water with a lower temperature as cooling water, and cools the steam by using the temperature difference between the steam and the hot water, so that the steam discharge is avoided, the conversion desalination water consumption is saved, and the cooling capacity is saved by using the hot water to cool. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The figure is a schematic diagram of the overall structure of the utility model.

[0015] In the figure: 1-hot water tank; 2-conversion hot water pump; 3-hot water cooler; 4-converter; 5-rectification hot water pump; 6-reboiler; 7-rectification tower; 8-steam condenser; A-hot water pump import pipe; B-conversion hot water upper water pipe; C-conversion hot water return pipe; D-rectification hot water upper water pipe; E-rectification hot water return pipe; F-steam pipe; K-steam venting pipe; X-circulating water pipe. DETAILED DESCRIPTION

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0017] Hot water tank 1 not only undertakes the important tasks of heat recovery and temperature control in the vinyl chloride production system, but also serves as a key link in energy conservation, emission reduction and optimized resource allocation in the entire production process. Therefore, hot water tank 1 is usually replenished with desalted water at the initial start-up of the device and steam is used for heating. Before start-up, the hot water temperature must be ensured to be ≥85°C.

[0018] like Figure 1 As shown, an energy-saving steam condenser on the top of a hot water tank in vinyl chloride production includes a hot water tank 1. A steam condenser 8 is provided on the top of the hot water tank 1. The shell outlet of the steam condenser 8 is connected to the return water outlet of the hot water tank 1 through a pipeline. The hot water tank 1 is connected to the steam condenser 8 by providing a steam pipe F. The top of the shell side of the steam condenser 8 is connected to a steam vent pipe K. The main function is that the steam generated when the temperature of the hot water tank 1 is relatively high, usually ≥96°C, is indirectly heat-exchanged with the distillation return water at a lower temperature through the steam condenser 8 to achieve condensation of the steam. The condensed steam condensate flows to the hot water tank 1 by its own gravity.

[0019] The bottom of the hot water tank 1 is connected to the conversion hot water pump 2 and the distillation hot water pump 5 respectively through the hot water pump inlet pipe A with a mechanical tee. The conversion hot water pump 2 is connected to the shell inlet and outlet of the hot water cooler 3 and the inlet of the converter 4 in sequence through the conversion hot water upper water pipe B. Circulating water and hot water are set through the pipe side for heat exchange to ensure the hot water temperature at the inlet of the converter 4. The outlet of the converter 4 is connected to the hot water tank 1 through the conversion hot water return pipe C. Mercury chloride catalyst is loaded through the pipe side for vinyl chloride synthesis reaction. Hot water is introduced into the shell side for heat removal. The conversion hot water enters from the bottom of the shell side, flows out from the top of the shell side, and is returned to the hot water tank 1 through the pipeline.

[0020] The outlet of the distillation hot water pump 5 is connected to the reboiler 6 through the distillation hot water supply pipe D, and the reboiler 6 pipe side is connected to the distillation tower 7. The reboiler 6 is connected to the steam condenser 8 pipe side inlet and the hot water tank 1 in sequence through the distillation hot water return pipe E. Hot water is introduced into the shell side to heat the material in the distillation tower 7 through indirect heat exchange, thereby avoiding waste of resources.

[0021] The hot water cooler 3 is connected to a circulating water pipe X; the hot water cooler 3, the converter 4, the reboiler 6 and the steam condenser 8 are shell-and-tube heat exchangers; the hot water temperature of the hot water tank 1 is ≥85°C before operation; the outlet temperature of the hot water cooler 3 is controlled to be 90±1°C; hot water is introduced into the shell side to indirectly provide heat to the materials in the distillation tower 7. During this process, the return temperature of the distillation hot water will decrease, and the return temperature of the distillation hot water in the distillation hot water return pipe E is 65°C±5°C.

[0022] The hot water cooler 3 mainly functions to cool the converted hot water. During the system operation, the hot water tank 1 is at a high temperature. In order to ensure that the circulating hot water in the converter 4 is lower than the reaction temperature in the converter 4, the outlet temperature of the hot water cooler 3 is usually controlled at 90±1℃, so as to ensure that the converter 4 can be timely cooled, and the circulating water pipe X is connected to the circulating water for cooling.

[0023] The hot water outlet of the converter 4 is connected to the hot water tank 1 through the converted hot water return pipe C. The return process will cause the temperature of the hot water tank 1 to rise. When the temperature of the hot water tank is ≥96℃, the generated steam is discharged through the steam vent pipe K. When the temperature of the hot water tank 1 is high, usually ≥96℃, the generated steam is indirectly exchanged with the rectification return water at a lower temperature through the steam condenser 8 to realize the condensation of the steam. The condensed steam condensate flows to the hot water tank 1 by gravity.

[0024] Before the device is operated, all the pipes and fittings in the device need to be pressure tested and leaked. The pressure is 1.0MPA. The metal winding gasket is used for the flange connection of each pipe. The high-temperature resistant material is used for the design of the steam condenser 8. During the operation of the device, the temperature difference between the rectification return water and the hot water tank should be ≥20℃.

[0025] According to the principle that the temperature of the converted hot water return water will rise and the temperature of the rectification hot water return water will decrease due to the different functions of the hot water in the converter 4 and the rectification tower 7, the steam condenser 8 is arranged at the top of the hot water tank 1, the rectification hot water return water is used for cooling, the condensation of the steam at the top of the hot water tank 1 is realized, and the cold energy during the operation of the system is saved.

Claims

1. A steam condenser for the top of a hot water tank in the production of vinyl chloride, comprising a hot water tank, characterized in that: The hot water tank (1) top is equipped with steam condenser (8), hot water tank (1) is connected with steam condenser (8) through setting steam pipe (F), steam condenser (8) is connected with steam vent pipe (K); Hot water tank (1) bottom is connected with conversion hot water pump (2) and rectification hot water pump (5) through hot water pump inlet pipe (A) respectively, conversion hot water pump (2) is connected with hot water cooler (3) and converter (4) in turn through conversion hot water up pipe (B), converter (4) is connected with hot water tank (1) through conversion hot water backwater pipe (C); Rectification hot water pump (5) is connected with reboiler (6) through rectification hot water up pipe (D), reboiler reboiler (6) is communicated with rectification tower (7), reboiler reboiler (6) is connected with steam condenser (8) and hot water tank (1) in turn through rectification hot water backwater pipe (E).

2. A steam condenser for the top of a hot water tank in vinyl chloride production according to claim 1, characterized in that: The hot water cooler (3) is communicated with a circulating water pipe (X).

3. The energy-saving steam condenser at the top of a hot water tank in vinyl chloride production according to claim 1 or 2, characterized in that: The hot water cooler (3), the converter (4), the reboiler (6) and the steam condenser (8) are shell-and-tube heat exchangers.

4. A steam condenser for the top of a hot water tank in vinyl chloride production according to claim 3, characterized in that: The hot water temperature of the hot water tank (1) before starting is greater than or equal to 85 DEG C.

5. A steam condenser for the top of a hot water tank in vinyl chloride production according to claim 4, characterized in that: The outlet temperature of the hot water cooler (3) is controlled to be 90 DEG C ± 1 DEG C.

6. A steam condenser for the top of a hot water tank in vinyl chloride production according to claim 5, characterized in that: The rectification hot water backwater temperature in the rectification hot water backwater pipe (E) is 65 DEG C ± 5 DEG C. The hot water cooler (3), the converter (4), the reboiler (6) and the steam condenser (8) are shell-and-tube heat exchangers. The hot water temperature of the hot water tank (1) before starting is greater than or equal to 85 DEG C. The outlet temperature of the hot water cooler (3) is controlled to be 90 DEG C ± 1 DEG C. The rectification hot water backwater temperature in the rectification hot water backwater pipe (E) is 65 DEG C ± 5 DEG C.

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