Hydrogen chloride drying system

Abstract

The utility model discloses a hydrogen chloride drying system which comprises a drying tower, at least one silicon tetrachloride centrifugal pump and a silicon tetrachloride condenser, water-containing hydrogen chloride enters from the tower bottom of the drying tower and flows out from the tower top of the drying tower after being dried, and clean silicon tetrachloride enters a cooling liquid pipeline of the silicon tetrachloride centrifugal pump and flows out from the tower top of the drying tower. The water-containing hydrogen chloride flows out of the cooling liquid pipeline and then enters a feeding pipeline of the silicon tetrachloride centrifugal pump, an outlet of the feeding pipeline of the silicon tetrachloride centrifugal pump is connected with the tower top of the drying tower, and the silicon tetrachloride dries the water-containing hydrogen chloride in the drying tower. According to the hydrogen chloride drying process, the manual cleaning link of the filter on the inlet pipeline of the silicon tetrachloride centrifugal pump is canceled, the manpower loss is reduced, the safety of operators is ensured, and the corrosion of the overflowed hydrogen chloride gas to the environment and equipment is reduced.

Description

Technical Field

[0001] The present application relates to a trichlorosilane production system, and in particular to a hydrogen chloride drying system. Background Art

[0002] Trichlorosilane is produced by combining silicon powder and hydrogen chloride gas in a fluidized bed reactor. Upon contact with water, the resulting hydrogen chloride decomposes to form hydrogen chloride gas. However, the hydrogen chloride synthesized from hydrogen and chlorine contains a significant amount of water. Once this water enters the system, it reacts with trichlorosilane to form silicon dioxide, clogging equipment in subsequent production steps. This ultimately reduces silicon powder conversion and increases production costs. Therefore, controlling the water content of the hydrogen chloride raw material is key to improving conversion efficiency and reducing production costs.

[0003] Silicon tetrachloride is typically used to dry hydrogen chloride. Silicon tetrachloride reacts with water to produce hydrogen chloride and silicon dioxide, without producing other impurities. Hydrogen chloride gas containing water enters the bottom of the drying tower. From there, it ascends and is pumped by a centrifugal pump to the top of the drying tower, where it begins spraying. The sprayed hydrogen chloride gas and silicon tetrachloride mixed with hydrogen chloride gas enter the condenser from the top of the drying spray tower for condensation.

[0004] The centrifugal pump used to pump silicon tetrachloride requires daily cleaning of the inlet filter, placing heavy workload on operators. Furthermore, cleaning the filter involves handling materials, exposing operators to hazardous conditions and the risk of poisoning or suffocation, potentially leading to occupational health hazards. Furthermore, within the hydrochloric acid plant, the centrifugal pump's blue filter gland may not be completely replaced during cleaning, leading to hydrolysis of the silicon tetrachloride in the air and the release of hydrogen chloride gas. This pollutes the environment, corrodes on-site piping and equipment, and shortens the life of the silicon tetrachloride centrifugal pump. Summary of the Invention

[0005] The purpose of the present application is to provide a hydrogen chloride drying system, which does not require a filter to be arranged before a silicon tetrachloride centrifugal pump.

[0006] To achieve the above objectives, the technical solution adopted in this application is: a hydrogen chloride drying system, comprising a drying tower, at least one silicon tetrachloride centrifugal pump and a silicon tetrachloride condenser, wherein aqueous hydrogen chloride enters from the bottom of the drying tower and flows out from the top of the drying tower after being dried, clean silicon tetrachloride enters the coolant pipe of the silicon tetrachloride centrifugal pump, and after flowing out of the coolant pipe, enters the feed pipe of the silicon tetrachloride centrifugal pump, the outlet of the feed pipe of the silicon tetrachloride centrifugal pump is connected to the top of the drying tower, and the silicon tetrachloride dries the aqueous hydrogen chloride in the drying tower.

[0007] As a preferred embodiment, the method comprises a plurality of silicon tetrachloride centrifugal pumps connected in parallel.

[0008] As another preference, a hydrolyzate discharge port is provided between the feed pipe outlet of the silicon tetrachloride centrifugal pump and the drying tower, and the hydrolyzate discharge port is suitable for discharging the silicon tetrachloride containing the hydrolysis product.

[0009] As another preferred embodiment, a silicon tetrachloride condenser is further included, wherein the clean silicon tetrachloride enters the bottom of the drying tower, the silicon tetrachloride flowing out from the bottom of the drying tower enters the feed pipe of the silicon tetrachloride centrifugal pump, and the silicon tetrachloride flowing out of the feed pipe of the silicon tetrachloride centrifugal pump enters the top of the drying tower.

[0010] As another preferred embodiment, a silicon tetrachloride condenser is further included, and the outlet of the feed pipe of the silicon tetrachloride centrifugal pump is connected to the inlet of the silicon tetrachloride condenser, and the silicon tetrachloride enters the drying tower after being condensed.

[0011] More preferably, the drying tower further comprises a hydrogen chloride condenser, and the dry hydrogen chloride flowing out of the top of the drying tower is condensed through the hydrogen chloride condenser.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] (1) The dry hydrogen chloride system of the present application runs clean silicon tetrachloride in the coolant pipe of the silicon tetrachloride centrifugal pump, which does not contain hydrolysis product silicon dioxide. The filter device before the silicon tetrachloride centrifugal pump can be removed, thereby eliminating the operator's operation of cleaning the filter screen and ensuring the operator's safety.

[0014] (2) The dry hydrogen chloride system of the present application reduces the leakage of hydrogen chloride gas during cleaning, reduces pollution to the environment and corrosion of equipment, and can extend the service life of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a partial device system flow chart of this application.

[0016] Figure 2 This is another part of the device system flow chart of this application.

[0017] In the figure: 1. Drying tower; 2. Silicon tetrachloride centrifugal pump; 3. Silicon tetrachloride condenser; 4. Hydrogen chloride condenser. DETAILED DESCRIPTION

[0018] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0019] In the description of this application, it should be noted that for directional words, such as the terms "center", "horizontal", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and so on, the directions and positional relationships indicated are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific scope of protection of this application.

[0020] It should be noted that the terms "first", "second", etc. in the description and claims of this application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0021] The terms "comprises" and "having" and any variations thereof in the specification and claims of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, product or apparatus.

[0022] The present application provides a hydrogen chloride drying system, such as Figure 1 As shown, the process includes a drying tower 1 and at least one silicon tetrachloride centrifugal pump 2. The aqueous hydrogen chloride gas from the synthesis furnace and the silicon tetrachloride from the distillation tower respectively enter the bottom of the drying tower 1. The silicon tetrachloride flowing out of the bottom of the drying tower 1 is pumped to the top of the drying tower 1 by the silicon tetrachloride centrifugal pump 2 and begins to be sprayed. The aqueous hydrogen chloride gas from the bottom to the top of the drying tower 1 contacts the silicon tetrachloride spraying downward. The silicon tetrachloride reacts with water to produce hydrogen chloride and silicon dioxide, which dries the aqueous hydrogen chloride without generating other impurities.

[0023] Silicon tetrachloride from the distillation tower enters the coolant pipe of silicon tetrachloride centrifugal pump 2, flows out of the coolant pipe of silicon tetrachloride centrifugal pump 2 and enters the feed pipe of silicon tetrachloride centrifugal pump 2. After being pumped, it enters the drying tower 1 from the top of the tower for spray drying of aqueous hydrogen chloride.

[0024] The hydrogen chloride drying system of the present application introduces clean silicon tetrachloride into the silicon tetrachloride centrifugal pump 2, thereby preventing large impurities such as silicon dioxide from forming after the reaction of silicon tetrachloride with water and clogging the coolant pipeline. This eliminates the need to install a filter or filter screen before the silicon tetrachloride centrifugal pump in conventional hydrogen chloride drying systems, further eliminating the need for manual cleaning of the filter, reducing labor losses, ensuring the safety of operators, and reducing corrosion to the environment and equipment caused by leaking hydrogen chloride gas.

[0025] In some embodiments, multiple silicon tetrachloride centrifugal pumps 2 are provided to improve the pumping efficiency of silicon tetrachloride. The multiple silicon tetrachloride centrifugal pumps 2 are preferably arranged in parallel, and the coolant pipeline outlets of the multiple silicon tetrachloride centrifugal pumps 2 are respectively connected to the feed pipeline inlet of the corresponding silicon tetrachloride centrifugal pump 2, so that the silicon tetrachloride in the drying tower 1 can have a stable flow rate.

[0026] like Figure 2 As shown, clean silicon tetrachloride from the silicon tetrachloride distillation tower (not shown) enters the bottom of the drying tower 1, and the silicon tetrachloride flowing out of the bottom of the drying tower 1 enters the feed pipe of the silicon tetrachloride centrifugal pump 2. The silicon tetrachloride flowing out of the feed pipe of the silicon tetrachloride centrifugal pump 2 enters from the top of the drying tower 1, and the aqueous hydrogen chloride is spray-dried in the drying tower 1.

[0027] The coolant of the silicon tetrachloride centrifugal pump 2 enters the inlet of the feed pipe from the coolant outlet, mixes with the silicon tetrachloride flowing out of the bottom of the drying tower 1, and is pumped to the top of the drying tower 1.

[0028] In some embodiments, a hydrolyzate discharge port is provided between the coolant pipe outlet of the silicon tetrachloride centrifugal pump 2 and the top inlet of the drying tower 1. After the hydrogen chloride drying device has been running for a period of time, the hydrolyzate discharge port is suitable for discharging and cleaning the silicon tetrachloride containing the hydrolysis product.

[0029] In some embodiments, a silicon tetrachloride condenser 3 is also included. The silicon tetrachloride condenser 3 is arranged between the feed pipe outlet of the silicon tetrachloride centrifugal pump 2 and the top inlet of the drying tower 1. Silicon tetrachloride flows out of the feed pipe outlet of the silicon tetrachloride centrifugal pump 2 and enters the silicon tetrachloride condenser 3 for condensation, and then enters the drying tower 1.

[0030] In some embodiments, the dried hydrogen chloride flows out from the top of the drying tower 1, passes through the hydrogen chloride condenser 4 for condensation, and then enters the subsequent process.

[0031] In some embodiments, Freon is used as the condensing liquid of the silicon tetrachloride condenser 3 and the hydrogen chloride condenser 4 .

[0032] The hydrogen chloride drying system of this application utilizes silicon tetrachloride to dry aqueous hydrogen chloride. The resulting hydrogen chloride can be reused, while silicon dioxide is discarded as a solid, fully utilizing silicon tetrachloride, a byproduct of trichlorosilane production. Furthermore, the significant difference in boiling points between silicon tetrachloride and hydrogen chloride facilitates separation. The drying equipment is readily available and easy to deploy, resulting in a highly cost-effective solution.

[0033] The present invention's drying hydrogen chloride system utilizes clean silicon tetrachloride (SiCl2) within the coolant pipeline of the SiCl4 centrifugal pump 2, eliminating the need for operators to clean the filter screen and ensuring operator safety. This system also reduces the leakage of hydrogen chloride gas during cleaning, minimizing environmental pollution and equipment corrosion. Finally, the circulation cleanliness of the SiCl4 centrifugal pump 2 is guaranteed, extending the service life of the entire drying hydrogen chloride system.

[0034] The above describes the basic principles, main features, and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above embodiments. The above embodiments and description merely illustrate the principles of the present application. Various changes and improvements may be made to the present application without departing from the spirit and scope of the present application. These changes and improvements are intended to fall within the scope of the present application. The scope of protection claimed by the present application is defined by the appended claims and their equivalents.

Claims

1. A hydrogen chloride drying system comprising a drying tower, at least one silicon tetrachloride centrifugal pump and a silicon tetrachloride condenser, wherein the bottom of the drying tower is provided with an inlet for aqueous hydrogen chloride and an inlet for silicon tetrachloride, and the top of the drying tower is provided with an outlet for dried hydrogen chloride, characterized in that: The discharge port at the bottom of the drying tower is connected to the feed pipe inlet of the silicon tetrachloride centrifugal pump, the coolant pipe outlet of the silicon tetrachloride centrifugal pump is connected to its feed pipe inlet, silicon tetrachloride is suitable for entering the coolant pipe inlet of the silicon tetrachloride centrifugal pump, and the feed pipe outlet of the silicon tetrachloride centrifugal pump is connected to the top of the drying tower, so that silicon tetrachloride sprays and dries the aqueous hydrogen chloride in the drying tower.

2. The hydrogen chloride drying system according to claim 1, characterized in that: The invention comprises a plurality of silicon tetrachloride centrifugal pumps connected in parallel.

3. The hydrogen chloride drying system according to claim 1, characterized in that: A hydrolyzate discharge port is provided between the feed pipe outlet of the silicon tetrachloride centrifugal pump and the drying tower, and the hydrolyzate discharge port is suitable for discharging the silicon tetrachloride containing hydrolysis products.

4. The hydrogen chloride drying system according to claim 1, characterized in that: It also includes a silicon tetrachloride condenser, and the outlet of the feed pipe of the silicon tetrachloride centrifugal pump is connected to the inlet of the silicon tetrachloride condenser, which is suitable for silicon tetrachloride to enter the drying tower after condensation.

5. The hydrogen chloride drying system according to claim 1, characterized in that: The drying tower further comprises a hydrogen chloride condenser, wherein the top discharge port of the drying tower is connected to the inlet of the hydrogen chloride condenser and is suitable for condensing the dried hydrogen chloride.

Images