The present invention relates to a method for preparing an apparatus (or a plant comprising a plurality of apparatuses), for example a heat exchanger, a vaporizer or a distillation column, for use in a process (in particular a continuously operated process) for concentrating a mineral acid by evaporation of water, wherein the apparatus or the plant comprises (at least) a device which is resistant to the mineral acid and the device is flushed with an aqueous alkali metal hydroxide solution having a concentration by mass of alkali metal hydroxide in the range from 1% to 30% at a temperature in the range from 40° C. to 90° C. for a time of from 2 hours to 7 days.

Process for the removal of particulate matter from an aqueous stream containing a concentrated acid, preferably concentrated sulfuric acid, the process including mechanical filtration by passing the aqueous stream through a filter unit, the filter unit including a metallic, ceramic or polymeric filter, or a filter including a filter aid on a septum. The aqueous stream is the exit stream of a sulfuric acid condenser, optionally the exit stream of a sulfuric acid concentrator arranged downstream the sulfuric acid condenser.

Process for the removal of particulate matter from an aqueous stream containing a concentrated acid, preferably concentrated sulfuric acid, the process including mechanical filtration by passing the aqueous stream through a filter unit, the filter unit including a metallic, ceramic or polymeric filter, or a filter including a filter aid on a septum. The aqueous stream is the exit stream of a sulfuric acid condenser, optionally the exit stream of a sulfuric acid concentrator arranged downstream the sulfuric acid condenser.

The present invention relates to a process for the separation of strong acid from its salts. In said process, a strong acid salt is reacted with organic weak base (OWB) in the presence of a hydrophilic solvent and CO.sub.2. The cation of the strong acid salt is precipitated to produce a carbonate/bicarbonate salt and the strong acid form a liquid salt with the OWB. The above process is performed in a solution comprising both the strong acid salt and the WBO. In the next step, the strong acid is released from its OWB liquid salt and the OWB is returned to a previous step.

A method for fractionating a sulfuric acid process stream having at least 1 wt % sulfuric acid, using a treatment system comprising three filtration assemblies each having membranes that are suitable to pass less than 10% salt in a standard test such that average passage of sulfuric acid from the first and third filtration assemblies is less than 30% and average passage of sulfuric acid from second filtration assembly is more than 70%. The system produces a fraction of the stream with a pH between 4 and 10, and a second fraction that contains at least 20 weight percent of sulfuric acid.

Provided is an unique, efficient and cost-effective process for the recovery of acid from acid-rich solutions. The process of the subject matter utilizes a strong oxidizer, such as Caro's acid, to disintegrate or render insoluble organic or inorganic materials such as carbohydrates and complexes thereof contained in acid-rich solutions, to make efficient and simple the separation and recovery of the acid solution. The acid recovered thus obtained is free of organic matter, and containing nearly all of the acid originally contained in the acid-rich solution.

Disclosed is a methanol and sulfuric acid co-production system capable of producing methanol and sulfuric acid in equal equivalents. Specifically, the system includes an oxidation reaction unit configured to produce methyl bisulfate (CH.sub.3OSO.sub.3H) by reacting methane gas with an acid solution in the presence of a catalyst, a reactive distillation unit disposed downstream of the oxidation reaction unit and configured to esterify methyl bisulfate (CH.sub.3OSO.sub.3H) supplied from the oxidation reaction unit with trifluoroacetic acid (CF.sub.3COOH) to obtain a product and to separate the product into methyl trifluoroacetate (CF.sub.3COOCH.sub.3) and sulfuric acid (H.sub.2SO.sub.4) through thermal distillation, and a hydrolysis reaction unit disposed downstream of the reactive distillation unit and configured to produce methanol by hydrolyzing methyl trifluoroacetate (CF.sub.3COOCH.sub.3) supplied from the reactive distillation unit, in which the reactive distillation unit recirculates the sulfuric acid resulting from separation to the oxidation reaction unit.

Disclosed is a methanol and sulfuric acid co-production system capable of producing methanol and sulfuric acid in equal equivalents. Specifically, the system includes an oxidation reaction unit configured to produce methyl bisulfate (CH.sub.3OSO.sub.3H) by reacting methane gas with an acid solution in the presence of a catalyst, a reactive distillation unit disposed downstream of the oxidation reaction unit and configured to esterify methyl bisulfate (CH.sub.3OSO.sub.3H) supplied from the oxidation reaction unit with trifluoroacetic acid (CF.sub.3COOH) to obtain a product and to separate the product into methyl trifluoroacetate (CF.sub.3COOCH.sub.3) and sulfuric acid (H.sub.2SO.sub.4) through thermal distillation, and a hydrolysis reaction unit disposed downstream of the reactive distillation unit and configured to produce methanol by hydrolyzing methyl trifluoroacetate (CF.sub.3COOCH.sub.3) supplied from the reactive distillation unit, in which the reactive distillation unit recirculates the sulfuric acid resulting from separation to the oxidation reaction unit.

Sulphuric acid plants, separators for separating entrainment for process gas, and gas treatment processes for generating sulphuric acid are provided. The sulphuric acid plant comprises a source of process gas, an entrainment eliminator, a gas rotator located downstream of the gas-liquid contactor, and a separator located downstream of the entrainment eliminator and upstream of the gas rotator. The separator comprises a plurality of passages. Each passage comprises a vane extending longitudinally along the passage, wherein each vane rotates a process gas flowing through the separator. The process comprises transferring process gas from an entrainment eliminator to a separator located downstream of the entrainment eliminator, rotating the process gas through the separator to separate entrainment, and transferring the separated process gas from the separator to rotating equipment located downstream of the separator.

Sulphuric acid plants, separators for separating entrainment for process gas, and gas treatment processes for generating sulphuric acid are provided. The sulphuric acid plant comprises a source of process gas, an entrainment eliminator, a gas rotator located downstream of the gas-liquid contactor, and a separator located downstream of the entrainment eliminator and upstream of the gas rotator. The separator comprises a plurality of passages. Each passage comprises a vane extending longitudinally along the passage, wherein each vane rotates a process gas flowing through the separator. The process comprises transferring process gas from an entrainment eliminator to a separator located downstream of the entrainment eliminator, rotating the process gas through the separator to separate entrainment, and transferring the separated process gas from the separator to rotating equipment located downstream of the separator.