RU2353576C2 - Method of liquid sulphur de-gassing - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to methods of hydrogen sulphide withdrawal from liquid sulphur and is designed for implementation at enterprisers of oil and gas processing industry at production of elemental sulphur. Liquid sulphur is de-gassed by means of mixing liquid sulphur with a catalyst. As the catalyst air is used; also sulphur extracted from a process equipment is mixed with air in a flask containing ferromagnetic mixing elements; the flask is installed in a space of a stator with three-phase coil connected to a source of alternate current. Fragments of magnets of 3-5 mm fraction are used as ferromagnetic elements.

EFFECT: invention facilitates reducing time of de-gassing without reduction of quality.

2 cl, 1 tbl

Description

The invention relates to methods for removing hydrogen sulfide from liquid sulfur and is intended for use in enterprises of the oil and gas processing industry in the production of elemental sulfur for its degassing.

A known method of purifying liquid sulfur from hydrogen sulfide and its polysulfides in the presence of a catalyst, for example perihydro (1.3.5-dioxazin-5yl.) Alkane (PDA) [1].

The main disadvantages of this method are:

- rapid clogging of sulfur flues connecting the degassing tanks with the chimney due to the presence of sulfur vapor and liquid catalyst;

- significant air pollution by catalyst vapor and the need to create additional capacity for storage of the catalyst.

There is also a method of degassing liquid sulfur directly from the collection tank of the Claus plant by pumping it to a special degassing tank in which pumps for mixing and spraying through nozzles are installed. Next, sulfur is recycled and sprayed for several hours, after which it is pumped into a storage tank. The catalyst used is ammonia fed to the pump inlet during recirculation. This technology of the company SNEA (Austria) is currently used at the Astrakhan gas processing plant [2].

A significant disadvantage of this method, selected as the closest analogue to the prototype of the proposed technical solution, is the difficulty of further use of sulfur, because the presence of ammonia salts in it violates the technological processes of further processing of sulfur.

The technical result of the claimed invention is to reduce the degassing time without reducing its quality from 14 hours to 10 seconds with a hydrogen sulfide content of less than 10 ppm.

The problem is solved in the invention due to the fact that liquid sulfur discharged from technological devices is mixed in a flask with a catalyst, which is used as air, and a flask containing ferromagnetic mixing elements is installed in the stator space with a three-phase winding connected to an alternating source current.

In addition, the problem is solved in the invention due to the use of fractions of 3-5 mm fractions of magnet fragments as ferromagnetic elements.

The essential features of the claimed invention because of its non-obviousness are new, and their combination with the known features completely solve the problem, which can be attributed to the presence of the criterion of "inventive step" in this solution.

In addition, the known essential features in conjunction with common features for both the prototype and the claimed technical solution are associated with the problem being solved by a cause-effect relationship, in which each essential feature is necessary, and all together are sufficient to implement the task. Moreover, the implementation of the set of essential features is the reason for the emergence of the investigation in the form of the results of solving this problem. Hence the conclusion that the proposed solution meets the criterion of "industrial applicability" is legitimate.

The claimed technical solution is tested in laboratory conditions of the Astrakhan gas processing plant.

The results of this testing are given below.

Example

In a 200 ml stainless flask placed in a stator space with a three-phase winding connected to an alternating current source, 7 pieces ferromagnetic mixing elements were placed and 150 g liquid non-degassed sulfur was poured, taken after leaving the sulfur coagulator apparatus at the Klaus installation. When connected in each of the stator windings under the influence of an electric current pulsating with a frequency of 50 Hz, an alternating magnetic field was generated, rotating at a speed of 1500 rpm.

At the same time, ferromagnetic mixing elements 3-5 mm in size under the action of a rotating magnetic field began to move for 30 to 10 seconds. Soon, the movements of the ferromagnetic mixing elements became erratic due to multiple collisions with each other and the walls of the working area. As a result, a vortex layer arose in which the ferromagnetic mixing elements took a chaotic motion, and a region of the maximum possible mixing (for the given conditions) was formed, moreover, air was supplied through a stainless tube connected to the bulb from below, with a flow rate of 1.5 l / h From the upper surface of liquid sulfur, the resulting gases were blown.

The table below shows data on the quantitative content of gases in sulfur before and after the degassing process in the process of experimental laboratory experiments to verify the proposed method.

Table Data on the quantitative content of gases before and after the degassing process Experiments The content of total (including H ₂ S _x ) H ₂ S in liquid sulfur, ppm Without exposure to an alternating magnetic field 345 354 370 366 With exposure to an alternating magnetic field for 30 sec 55 45 43 41 With exposure to an alternating magnetic field for 20 seconds 35 31 thirty 25 With exposure to an alternating magnetic field for 10 seconds 10 8 5 traces

The proposed method of degassing sulfur has a number of obvious advantages compared with known similar methods, namely:

- allows you to completely abandon the use of sulfuric pumps for degassing;

- there is no need for continuous injection of a chemical ammonia catalyst to accelerate the decomposition of H ₂ S _x hydro polysulfides;

- simplification of temperature control degassing;

- reduced wear of the mixing elements due to the good lubricity of sulfur;

- simplification of the process of degassing;

- reduction in the capacity of the sulfur pit, and hence a reduction in capital costs.

Information sources

1. RF patent No. 2206497, IPC С01 В 17/02, 2000

2. Grunwald V.R. Sulfur technology. - M .: Chemistry, 1992 .-- 272 p.

Claims (2)

1. A method of degassing liquid sulfur by mixing liquid sulfur with a catalyst, characterized in that air is used as a catalyst, while sulfur removed from process apparatuses is mixed with air in a flask containing ferromagnetic mixing elements, which is installed in the stator space with a three-phase winding, connected to an AC source. 2. The method according to claim 1, characterized in that as the ferromagnetic elements using fragments of magnets fractions of 3-5 mm