9 results about "Spent caustic" patented technology

Processes and facilities for producing recycled chemical products from waste plastic are described herein. The processes include treating process streams, such as a pyrolysis gas stream and / or at least a portion of a cracker furnace effluent stream, in a caustic scrubber process to remove certain components, such as carbon dioxide. The spent caustic solution from the caustic scrubber process is then recycled and reused in other caustic processes within the facility, which can include a halogen neutralization process from removing halogens from a liquification process off-gas.

Processes for treating spent caustic in a hydrocarbon process utilizing HCl are described. The processes include sending the spent caustic to a caustic scrubbing system. HCl rich off gases are routed to the scrubbing system. This process is designed to deplete the NaOH in the spent caustic and form a brine solution. The brine is sent to an electrochemical cell to convert the NaCl to NaOH while generating chlorine and hydrogen gas. The NaOH generated from the electrochemical reaction is recycled back to the caustic scrubber, while the chlorine and hydrogen gas are combined and recycled back to the reaction zone.

Methods of treating natural gas or biogas include providing a caustic treatment composition comprising: a strong base; 0.005 to 0.025% wt / wt polyethylene or polypropylene glycol; and 0.005 to 0.02% wt / wt ethylenediaminetetraacetic acid or ethylenediamine; and a balance water; introducing a natural gas or a biogas and the caustic treatment composition into a caustic scrubber; and operating the caustic scrubber to remove hydrogen sulfide and one or more of an acid gas and carbon dioxide. Also, methods of precipitating the carbon dioxide include, to the aqueous spent caustic solution that has the carbon dioxide, adding a source of calcium ions to precipitate calcium carbonate and form a brine solution. The source of calcium ions is primarily calcium chloride and has calcium hydroxide as less than 1% wt / wt of the source of calcium ions. The method can include collecting the calcium carbonate precipitate, washing the calcium carbonate precipitate, and drying the calcium carbonate precipitate.

The present invention generally relates to a system and method for treating spent caustic effluent using chlorine dioxide solution. The system comprises a spent caustic storage tank for receiving spent caustic obtained from refinery operations; an acid storage container connected to the spent caustic storage tank for neutralizing free alkali content with a mineral acid to eliminate unwanted chemical reactions associated with free caustic present in spent caustic with ClO2; a heat exchanger unit engaged for reducing temperature of spent caustic to 35-45° C. from high temperature raised due to heat of neutralisation at least one of a cavitation (mixing) chamber or venturi mixing equipment mechanically connected downstream of the heat exchanger unit for adding ClO2 solution to the spent caustic solution to oxidize sulphide / thiols content for complete reduction of sulphide / mercaptane and reduction of 80-90% of COD.

This invention relates to the field of waste alkali liquid treatment technology, specifically to a waste alkali liquid treatment device and method, including a waste liquid tank and a baffle plate, the baffle plate being fixedly connected to the inner wall of the waste liquid tank, and also including a separation tank, a pressure plate, a scraper, a rotary drive assembly, a squeezing and draining assembly, and a reciprocating scraping assembly. The separation tank is rotatably installed in the waste liquid tank via the rotary drive assembly. In order to facilitate the extrusion of water contained in suspended solids, this invention achieves uniform distribution of suspended solids by rotating the separation tank at low speed while scraping, followed by a triple separation mode of initial separation through drainage holes, secondary dehydration by centrifugal force, and deep dehydration by pressure plate extrusion, which greatly improves the solid-liquid separation effect. Furthermore, a quantitative scraping design is adopted to avoid the scraper from spinning idly and causing ineffective wear on the equipment. At the same time, the separation and engagement of the toothed ring during the lifting and lowering of the pressure plate achieves precise linkage and disconnection between the rotary drive assembly and the reciprocating scraping assembly, which can prevent the scraper from accidentally scraping out suspended solids during the dehydration stage.

The application provides a treatment method of sulfur-containing waste lye, which comprises the following steps: carrying out oil removal treatment on the waste lye, and then carrying out first-stage wet oxidation treatment; controlling reaction conditions to make 10%-90% of S 2‑ in the waste lye be converted into S2O3 2‑ ; adding a co-oxidation promoter into effluent water to carry out catalytic wet oxidation treatment, so as to realize synchronous oxidation of organic matters and S 2‑ , and the co-oxidation promoter is at least one selected from peroxide, persulfate, percarbonate and peroxymonosulfate. The application adopts two-stage wet oxidation, and the temperature of each stage is relatively low. By controlling the conditions of the first-stage wet oxidation, 10%-90% of S 2‑ in the waste lye is converted into S2O3 2‑ , and by adding a co-oxidation promoter into the second-stage wet oxidation, S2O3 2‑ reacts to generate free radicals which can accelerate the wet oxidation, so as to accelerate the degradation of the organic matters, and the purpose of treating waste with waste is realized. The reaction conditions of the two-stage wet oxidation are relatively mild, the energy consumption is reduced, and the COD removal efficiency is greatly improved.

The spent caustic is the wastewater resulting from removing acidic gases with a pH higher than 14 and containing hazardous environmental pollutants and a very unpleasant smell. There are many serious process and material selection challenges for treating this wastewater. The existing method for its treatment is to use wet air oxidation (WAO), which is conducted under high temperatures and pressure and is faced with many operational challenges for implementation in a refinery or petrochemical plant environment. In this invention, the membrane system is used to inject carbon dioxide for treatment. This system operates under ambient temperature and pressure and does not experience acid injection problems in a semi-closed system. This product is equipped with modular gasification units. Also, to complete the spent caustic treatment cycle, an advanced oxidation process (AOP) system can be added to the membrane system.

A spent caustic treatment process addresses the shortcomings with traditional Wet Air Oxidation Systems. The process can treat either refinery or sulphidic spent caustic streams with CODs of up to 50,000 mg / L. The process uses >90% oxygen as an oxidising agent. A horizontal, tubular reactor is operated at pressures between 100 and 170 Bar (ideally 145-165 Bar). The reactor has an operating temperature of between 120° C. and 320° C., ideally 280° C. to 300° C. A closed heat transfer medium circulation loop is utilised for heat recovery from the reactor effluent stream to the spent caustic feed stream. The invention allows for a COD reduction of 7 5 to 99.9%.

Processes for treating spent caustic in a hydrocarbon process utilizing HCI are described. The processes include sending the spent caustic to a caustic scrubbing system. HCI rich off gases are routed to the scrubbing system. This process is designed to deplete the NaOH in the spent caustic and form a brine solution. The brine is sent to an electrochemical cell to convert the NaCI to NaOH while generating chlorine and hydrogen gas. The NaOH generated from the electrochemical reaction is recycled back to the caustic scrubber, while the chlorine and hydrogen gas are combined and recycled back to the reaction zone.