Hydrogen sulphide scavenger for light and volatile petroleum products

Abstract

The invention relates to the field of neutralizing hydrogen sulphide and light mercaptans in oil industry fluids using chemical neutralizing reagents and is applicable in the oil and gas industry for cleaning and neutralizing oil transport tanks, pipelines, heat exchangers, fractionating and distillation columns, reactors, filters, settling tanks, gas scrubbers, air coolers, temporary storage tanks and any other receptacles and piping used in oil and gas processing. The proposed hydrogen sulphide scavenger for light and volatile petroleum products contains 95% ethyl alcohol solution, carbohydrazide, grade A 25% ammonia solution, GD anti-foaming agent, 3% hydrogen peroxide solution, concentrated soap (pH=14) and demineralized water in a given ratio of components. The present invention provides a composition that reduces or eliminates the presence of hydrogen sulphide in various fluids.

Description

[0001] HYDROGEN SULFIDE ABSORBER

[0002] FOR LIGHT AND VOLATILE OIL PRODUCTS (RU)

[0003] HYDROGEN SULFIDE ABSORBER FOR LIGHT AND VOLATILE OIL PRODUCTS (ENG)

[0004] The invention relates to the field of neutralizing hydrogen sulfide and light mercaptans in oil field environments using chemical neutralizing reagents and can be used in the oil and gas industry for cleaning and neutralizing oil transport tanks, pipelines, heat exchangers, rectification and distillation columns, reactors, filters, settling tanks, gas scrubbers, air coolers, temporary storage tanks and any other capacitive equipment used in the process of oil and gas refining.

[0005] During scheduled maintenance at oil and gas processing plants, many companies encounter the presence of hazardous residual products within equipment such as distillation and distillation columns, heat exchangers, filters, temporary storage tanks, reactors, pipelines, and other process equipment. Such residues are almost always flammable and toxic, forcing plant operators to neutralize and clean them (chemical and mechanical cleaning is performed after neutralization).

[0006] In many cases, neutralization is performed in the following order: shutting down the apparatus, draining it, steaming it with water vapor (primitive, traditional neutralization), opening the apparatus, and then mechanically or chemically cleaning it of residual product deposits. This traditional procedure entails a number of inconveniences, risks, and costs, such as: lengthy steam cleaning times, entry into a confined space and hazardous gas environment for mechanical and chemical cleaning, and expensive disposal of the generated waste.

[0007] Compositions and methods are known that are useful for removing, reducing, or otherwise controlling hydrogen sulfide and mercaptans. These compositions and methods can be used in any industry where hydrogen sulfide poses a problem, such as when handling crude oil, natural gas, and / or coal-based products. The present invention provides compositions and methods that can reduce or eliminate hydrogen sulfide in various environments (CA 2982407 A1, October 27, 2016). However, these known solutions neutralize hydrogen sulfide in product lines during production and do not possess the cleaning properties of the present invention.

[0008] The closest analogue is an absorption solution (RU№2134149 Cl, 10.08.1999) for purifying gases from hydrogen sulfide, including formaldehyde and water, characterized in that it additionally contains sodium or potassium carbonate or bicarbonate in the following ratio of components, wt. %:

[0009] Formaldehyde - 1-37

[0010] Sodium or potassium carbonate or bicarbonate - 0.01 0.1 Water - Rest

[0011] The disadvantages of the known solution are the low degree of purification and low selectivity for hydrogen sulfide.

[0012] The problem that the invention is aimed at solving is the creation of a hydrogen sulfide absorbent composition that has processability (low freezing point) and high reactivity (neutralizing) capacity in relation to hydrogen sulfide and mercaptans in light and volatile petroleum products with the presence of a liquid phase inside the vessel.

[0013] The technical result of solving the stated problem is the creation of an absorbent composition that ensures highly effective neutralization of hazardous compounds in devices removed from the production process while simultaneously cleaning their surfaces from residues of petrochemical products.

[0014] The said technical result is achieved by the fact that a hydrogen sulfide absorber for light and volatile petroleum products is proposed, including an ether-aldehyde fraction (95%) (wherein the content of fusel oils in the ether-aldehyde fraction is not less than 2.2%), carbohydrazine, which acts as an inhibitor for slowing down the corrosion rate, aqueous ammonia of type A (25%), used for activating water, a GD defoamer that prevents foaming, hydrogen peroxide 3%, concentrated soap that does not leave traces (pH 14), and as water contains demineralized water in the following ratio of components, by weight. %: ether-aldehyde fraction (95%) 10 carbohydrazine 0.05 aqueous ammonia of type A (25%) 0.05

[0015] GD-defoamer 0.02 hydrogen peroxide 3% 0.02 concentrated soap that leaves no traces (pH 14) 2.0 demineralized water 87.86

[0016] Method of preparation of the proposed absorber.

[0017] To prepare the composition, first take demineralized water at room temperature (+20°C) and activate it by adding aqueous ammonia. After adding the ammonia, sparge it to mix. Next, add the EAF to the activated water and sparge again. Then add all the remaining components (the order of addition is not required), and sparge again.

[0018] These compositions were selected experimentally using a small distillation apparatus and a steam generator, and the following were used as neutralized and purified objects: crude oil from the Kashagan field (high content of sulfides), road bitumen, AI92 gasoline, summer-quality diesel fuel, toluene, solvent 646, a section of gas pipeline with a diameter of 25 mm and a length of 2 meters, which had been in operation for 15 years.

[0019] Changing the steam flow and chemical assembly injection rate changes the desired result, so the injection rate should be selected experimentally during engineering surveys before the work begins.

[0020] The saturation method involves introducing the proposed absorbent directly into the steam stream under pressure, with the steam temperature ranging from 110°C to 230°C. To select the correct product injection rate into the steam line, it is important to accurately calculate the steam flow rate using the following parameters: the pipe diameter at the apparatus inlet, the steam pressure, the temperature, and the velocity. For example, a 25mm diameter pipeline with a pressure of 2 bar, a velocity of 30 m / s, and a temperature of +150°C will consume 100 kg per hour. With this flow rate, an injection ratio of 1:3 must be maintained, where 1 (one) is the product and 3 (three) is the steam. For example, when neutralizing and cleaning equipment after finished products such as gasoline, diesel, toluene, and benzene, more steam with a lower temperature (up to 130°C) and a smaller amount of the product are required.The proportions are selected empirically during engineering surveys using samples from the apparatus to be removed from the production process and subsequently repaired.

[0021] The chemical assembly is injected under pressure using medium- and high-pressure chemical pumps. During the testing of the saturation technology, DHDA33 and DHDA66 pumps from HydroTron, UK, were used. If multiple units in a single section are to be neutralized and cleaned simultaneously, the feed is sent to a distribution metering manifold, and the flow rate for each unit is then adjusted individually on the manifold. A flow meter, installed downstream of the distribution metering manifold, serves as a monitoring instrument.

[0022] As a result, steam saturated with the specified product simultaneously neutralizes and cleans all product deposits inside the device. That is, the alcohol and aldehyde components neutralize, while the alkaline-ammonia component cleans the surface of product residue. This allows more time for repairs to be performed on devices taken out of service.

[0023] Example 1: Our product was based on low-alcohol vodka (8% to 21%) to improve the conversion of hydrogen sulfide and mercaptans to triazine, as this absorbent is easy to produce and non-toxic. To remove surface deposits of residual products and prevent them from re-adhering, two types of concentrated soap with a pH of 14 were selected: Primalux (made in Belarus) and ALEX (made in Russia). Experimental trials using a distillation apparatus resulted in the best proportions, indicated in the percentage composition of the product above. This product is capable of not only neutralizing all hazardous compounds but also achieving excellent surface cleaning performance inside the apparatus. Further experiments revealed that household soap can also be used in the product manufacturing process, but a larger quantity is required, as household soap has a pH of 119-11 and is less caustic than industrial soap.The most successful experiments were repeated multiple times on the distillation unit, and the desired results were achieved each time. During the experiments, the content of the washed (test) vessel varied from light (gasoline and diesel) to heavy (crude oil and bitumen), yet the neutralization and purification results remained high. For chemical cleaning and neutralization during equipment steaming, this was the best procedure, accommodating the work schedule, and also reduced the steaming time (tested in practice during the steaming of 12 circuits on 6 heat exchangers at Section 3205 of the Atyrau Oil Refinery). Steaming with water vapor was scheduled for 72 hours, but using our product, it was completed in 36 hours.

[0024] Example 2: During the initial technology and product testing in October 2023 at the Atyrau Oil Refinery, plant personnel noted the absence of hydrogen sulfide and mercaptan odors, and environmental monitoring sensors at the plant and in the city showed no excess or deviations in air or ambient temperatures, confirming the effectiveness of the final reaction. After opening the apparatus, it was noted that all product deposits had been removed. Only one column, K1, in the AT2 section, lacked steam flow control, and it was discovered that the steam supply was insufficient because the steam line was clogged with scale deposits (carbonate). As a result, the desired effect was not achieved, necessitating significant additional, costly work.

[0025] All production and use procedures have been developed and implemented, first in trials on a mini-distillation apparatus and then in an existing production facility. Neutralization and purification of hydrogen sulfide and mercaptan compounds within vessels using our products results in the production of triazine, an antiseptic and disinfectant that is non-allergenic. It also disinfects the plant and surrounding areas, completely eliminates the release of hydrogen sulfide and mercaptan compounds into the atmosphere and surrounding areas, and simultaneously cleans the equipment, significantly reducing the cost of the work and shortening the time required to prepare the equipment for repair.The use of these products is especially important for facilities located in or near populated areas, as steam scalding produces a very strong odor of hydrogen sulfide and mercaptans and often entails violations of environmental legislation in cases where maximum permissible emissions are recorded by monitoring stations. Furthermore, since the input and discharge procedure strictly requires that saturated steam scalding be routed through flare headers to the flare, accumulated hazardous compounds in these flare lines, liquid settling tanks, and settling and discharge tanks are also neutralized and cleaned. Since such lines are almost never cleaned and neutralized during major repairs, when a flare is triggered during production, all hazardous compounds are always released into the atmosphere.

[0026] Thus, the proposed product offers several advantages: availability of all chemical assembly components on the domestic market in Kazakhstan and in neighboring countries; non-flammability and non-toxicity of the manufactured product; simultaneous neutralization properties; and effective cleaning of equipment from residual products.

Claims

CLAUSES OF THE INVENTION 1. A hydrogen sulfide absorber for light and volatile petroleum products, including water, characterized in that it additionally contains a 95% ether-aldehyde fraction, carbohydrazine, 25% aqueous ammonia grade A, a GD defoamer, 3% hydrogen peroxide, concentrated soap (pH 14), and contains demineralized water as water, in the following ratio of components, wt. %: 95% etheraldehyde fraction 10 carbohydrazine 0.05 25% aqueous ammonia grade A 0.05 GD-foam suppressor 0.02 3% hydrogen peroxide 0.02 concentrated soap (pH 14) 2.0 demineralized water 87.86 2. A hydrogen sulfide absorber according to claim 1, characterized in that the content of fusel oils in the ether-aldehyde fraction is at least 2.2%.