Treatment of diesel alkali residue

2006, Volume 16, Issue 02: Application of High-Concentration Wastewater Treatment Technology in the Treatment of Diesel Alkali Sludge. The wastewater generated by diesel alkali sludge in refineries contains phenols and sulfides with complex compositions, resulting in high concentrations of these substances. Dagang Petrochemical Company utilized high-concentration wastewater treatment technology for pre-biological treatment, and the trial operation of the related equipment as well as its application in treating diesel alkali sludge demonstrated the advancement of this technology. During the biological treatment process, the process system operated safely and reliably, with all technical parameters meeting or exceeding the design targets. Specifically, the CODCr level dropped from 34,744 mg/L before treatment to 370 mg/L, while ammonia nitrogen was kept below 50 mg/L. The high-concentration wastewater treatment technology features a simple process flow and causes no pollution to the surrounding environment.

Isn’t it better to just burn it right away?

For more specific information, one can search on the Intellectual Property Office of the People’s Republic of China; there may be more detailed details regarding the process for comprehensively treating diesel alkali slag using cyclic technology. Application number/patent number: 200810015301. This invention discloses a process for comprehensively treating diesel alkali slag through cyclic technology, addressing the issues of low raw material utilization efficiency and high costs associated with traditional methods, and providing an efficient and energy-saving solution. It includes the following steps: maintaining the temperature in a water bath between 50–100°C; using a high-efficiency polymeric demulsifier, mirabilite, sulfuric acid, and thermal methods in combination to carry out demulsification; adding sulfuric acid to adjust the pH value to between 6–10; using amounts of the demulsifier and mirabilite that correspond to 0.003%–0.03% of the weight of the alkaline residue and 10%–80% of its weight respectively; allowing the mixture to stand for 0.5–6 hours so that separation occurs, after which the waste alkaline water and diesel are separated. The spent alkaline water is acidified with sulfuric acid, the temperature is maintained at 50–80°C and the pH value is kept between 4–6; it is then left to stand for 1–8 hours to allow the recovery of phenol. Subsequently, it is acidified again to a pH value of 2–4, and left to stand for another 1–8 hours to enable the recovery of naphthenic acid. The recycled spent alkali water is concentrated and cooled to 10–30°C to induce crystallization, yielding mirabilite which is used as a demulsifier in a cyclic manner. To the wastewater after crystallization, 1–5 ppm of polyacrylamide is added by weight, followed by the addition of NaOH to prepare an alkaline washing solution, which is then used in the alkaline washing process for diesel.

Acidification of diesel alkali residue – recovery of crude naphthenic acid: The diesel alkali residue resulting from oil removal and sedimentation in the refining workshop is pumped out from the diesel alkali residue storage tank – 304/L,2 using pump – 304/1,2, and then transported via the north-south main pipes to feed tank D–401 in the naphthenic acid recovery unit of the industrial test facility for alkali residue treatment. It is then pumped out by the feed pump P—401/l,2 in the naphthenic acid recovery unit and sent to the mixer, where it undergoes a neutralization reaction with concentrated sulfuric acid. Concentrated sulfuric acid is transported from the wastewater treatment plant, under the force of non-purified air, to the sulfuric acid metering tanks D-406/1,2; from there, it is again pushed by non-purified air to the mixer where the reaction takes place. The pH is controlled at 2–3, and the mixture after the reaction enters the neutralization and sedimentation tank D-405 for sedimentation and separation. The pressure is kept at around 0.4 Mpa. The naphthenic acid at the top flows by gravity into the naphthenic acid intermediate tank D-404. Sent by pump P-403 to the naphthenic acid finished product tank in the wastewater treatment plant. The wastewater at the bottom of D-405 flows under its own pressure into the wastewater buffer tank D-403. The acidic wastewater then enters the wastewater treatment system. Acidification of gasoline alkali residue – recovery of crude phenol: After oil removal by sedimentation in the refining workshop, the catalytic gasoline alkali residue is pumped out using pump P-301 and transported via the north-south main pipes to feed buffer tank D-402 in the crude phenol recovery unit of the industrial test facility for alkali residue treatment. It is then drawn out by the crude phenol unit feed pump P-402/1,2 and sent to a mixer where it undergoes a neutralization reaction with concentrated sulfuric acid. Concentrated sulfuric acid is transported from the wastewater treatment plant under non-purified air pressure to the concentrated sulfuric acid metering tank D—406/1,2, and then again under non-purified air pressure to the mixer for reaction, with the pH maintained between 2 and 3. The mixture after the reaction enters D-407 for sedimentation and separation. The separated crude phenol flows by gravity from the top of D-H07 into the crude phenol product tank, and is then pumped out for delivery using the crude phenol loading pump P-406. The wastewater at the bottom of D-407 is pumped by pump P-405 into wastewater buffer tank D-403, from where it enters the wastewater treatment system. Treatment of alkaline slag wastewater: The diesel alkaline slag wastewater and gasoline alkaline slag wastewater from the alkaline slag acidification unit are mixed together and then fed into a bituminous coal adsorption filter tower; the wastewater after filtration is pumped into an iron shavings micro-electrolysis tower. The water after electrolysis enters the first buffer tank, from where it is pumped and sent to the water purifier; NaOH solution and a polymer flocculant are added before the pump to maintain a pH of 8.5. The clarified supernatant and sludge are each filtered through a microporous filter before entering the second buffer tank, where the pH of the water is adjusted to 6–7. The water then is pumped into the resin adsorption tower; the water after adsorption by the resin flows directly to the refinery’s wastewater treatment plant. The resin that has reached adsorption saturation is regenerated using an alkali, and the regenerated resin is then used for adsorption again. The desorbed phenol solution is pumped from the storage tank to the crude phenol neutralization and sedimentation tank D-107 for centralized treatment, where the crude phenol is separated out. The above process is for reference only; the alkali slag treatment system also needs to take corrosion prevention into account. Currently, the wet oxidation process is widely used! ! !

Check out the deep biological oxidation treatment technology

There are specialized services for recycling, and it can be ordered for delivery

Residue is incorporated as a fuel oil viscosity reducer. . . :lol

1. Diesel hydroprocessing can be considered to reduce the amount of alkaline slag. 2. Naphthenic acid is recovered after acidifying the alkali slag. After pH adjustment of the acidic water, its COD is between 20,000 and 40,000; SBR treatment is then applied to reduce the COD to below 2,000, after which it is sent to the wastewater treatment system.

This post was last edited by xuexue0909 on 2012-2-20 at 14:49. The Tianjin Dagang Petrochemical project mentioned above is one in which we have achieved great success; if you need any assistance, please contact Mr. Xu at 13901303805.

Which company or design firm do you work for?

Contact me at 18561036610, Xiao