Method for preparing macroporous aluminium sulfide/aluminium oxide mercury removal agent

Abstract

The invention provides a method for preparing a macroporous aluminium sulfide / aluminium oxide mercury removal agent. The method includes the steps of (1), mixing Rho-alumina powder, pseudo-boehmite dry powder and lubricant uniformly, adding solution containing phosphoric acid and ammonium dihydrogen phosphate, mixing, extruding and drying; (2), roasting the dry rods at the temperature of 950-1050DEG C to obtain an aluminum oxide carrier; (3), subjecting the aluminum oxide carrier to hot dipping in sodium polysulfide solution, standing in a closed and thermal-insulating environment, performingpurging of carbon dioxide, washing, and then drying at the temperature lower than 80 DEG C, so as to obtain the mercury removal agent. The mercury removal agent prepared by the method has high mercury removal precision and high capacity, taking off of powder is not easy to cause during long-term use, mercury removal precision and capacity is not affected by moisture and easy-to-coagulate hydrocarbon of materials, service cycle of the mercury removal agent is long, and changing frequency is low, and besides, the process that aluminum oxide carries sulphur is easy to control, and distribution of sulphur is uniform.

Description

technical field [0001] The invention belongs to the technical field of gas purification, and in particular relates to a method for preparing a macroporous sulfur / alumina mercury removal agent. Background technique [0002] Wellhead natural gas usually contains a small amount of mercury, generally lower than 200μg / m³, and sometimes as high as 1000μg / m³; in the process of recovery of condensate oil, liquefaction and nitrogen separation by low temperature methods, low temperature heat exchangers made of aluminum alloy such as plate-fin type should be installed For heat exchangers, the mercury contained in natural gas will form amalgam on the surface of aluminum alloy, which will cause the dense aluminum oxide film that plays a protective role to fall off, and the water and hydrogen sulfide contained in the natural gas flow will chemically react with the aluminum in the amalgam to accelerate Corrosion, after a long period of time, will cause corrosion and leakage of the heat exc...

AI Technical Summary

Problems solved by technology

[0005] It is generally believed that the amount of water and easily condensable hydrocarbons contained in natural gas is not easy to condense in the larger diameter pores of 35nm or more in the mercury removal agent, and the mercury removal agent is prepared by using a carrier with a large pore size and not too low specific surface area. The effect is good; but the main problem of preparing a carrier with a large pore size and a low specific surface area is the high cost, such as steps including pressurized hydrothermal treatment or atmospheric pressure high-temperature steam treatment, which are difficult or time-consuming

[0006] On the other hand, the processing of sulfur loaded on activated carbon or alumina carrier also has the problems of difficulty in control and uneven distribution of sulfur, and the cost is not low enough

Due to the fine pore size of columnar activated carbon, if it is dynamically mixed with sulfur powder at about 140°C to absorb sulfur in the form of liquid sulfur, it needs a long time of heat preservation to distribute uniformly. This problem also exists when sulfur is loaded on alumina with fine pore size; If it is dynamically mixed with sulfur powder at about 250°C for heat preservation, the sulfur can be inhaled in liquid and gaseous forms, and can be loaded evenly at a faster speed. High equipment requirements