A method is provided for removing tar from a gas by contacting a first gas containing tar with a second gas containing oxygen for time period sufficient to effect oxidation of at least a portion of the tar in the first gas, thus producing an oxidized product gas that contains less tar than the first gas. The method can also include heating a fluidized particulate material in a combustor, introducing the heated fluidized particulate material from the combustor and a biomass feedstock into a gasifier, such that heat from the heated fluidized particulate material causes the gasification of at least a portion of the biomass feedstock to form a tar-containing product gas, the first gas may contain at least a portion of the tar-containing gas, and the tar-containing gas may be extracted from the gasifier prior to contacting the first gas with the second gas.

Methods and systems for producing light olefins are disclosed. A feedstock comprising crude oil is distilled to produce a plurality of streams including a naphtha stream and a vacuum residue stream. The naphtha is fed to a steam cracking unit to produce light olefins, C.sub.4 hydrocarbons, pyrolysis gasoline and pyrolysis oil. The vacuum residue stream is hydrocracked to produce additional naphtha and heavy unconverted oil. The heavy unconverted oil and the pyrolysis oil from steam cracking unit can be deasphalted to produce deasphalted oil and pitch product. The deasphalted oil can be further hydrocracked to produce naphtha. The pitch product can be gasified to produce synthesis gas, which is further used to produce methanol. The methanol can be used to react with isobutylene of the C.sub.4 hydrocarbon stream from steam cracker to produce methyl tert-butyl ether (MTBE).

A system for gasifying biomass is disclosed. The system comprises a water storage tank, a water pump, a heat exchanger, a plasma torch heater, a gasifier, an ash cooler, a spray tower, a dust collector, a deacidification tower, and a desiccator. The water storage tank is connected to the water inlet of the heat exchanger; the vapor outlet of the heat exchanger is connected to the vapor inlet of the plasma torch heater; the vapor outlet of the plasma torch heater is connected to the vapor nozzle of the gasifier; the ash outlet of the gasifier is connected to the ash inlet of the ash cooler; the gas outlet of the gasifier is connected to the gas inlet of the spray tower; and the gas outlet of the spray tower is connected to the gas inlet of the heat exchanger.

A degradant concentration measurement device 14 according to the invention has an electric conductivity measurement instrument 71A measuring the electric conductivity of a lean solution 16 that is an acidic gas-absorbing solution and detection means 72 obtaining the concentration of a degradant contained in a lean solution 16 from the measured electric conductivity of the lean solution 16 based on the relationship between the previously-obtained electric conductivity of the lean solution 16 and the concentration of the degradant contained in the lean solution 16.

The system includes: an absorber which brings an introduction gas into contact with an absorbent that absorbs CO.sub.2 and H.sub.2S; an absorbent regenerator which releases CO.sub.2 or the like to regenerate the absorbent; a second supply line which returns a regenerated absorbent to the absorber from the regenerator; a third supply line which extracts a semi-rich solution from the vicinity of a middle stage of the absorber, and introduces the semi-rich solution to the vicinity of the middle stage of the regenerator; and a semi-rich solution heat exchanger which is interposed at an intersection between the third supply line and the second supply line to perform the heat exchange between the semi-rich solution and the lean solution.

There is provided an absorbent for decreasing the leakage of halogen compound gases in subsequent processes, at high temperatures and in the presence of high concentrations of water vapor in the process of heating and gasifying a fuel, such as coal, to produce a synthesis gas.

The adsorbent includes a halogen compound absorbent containing 30 to 90% by mass of a basic calcium compound and 10 to 70% by mass of a metal compound other than basic calcium compounds and/or of a clay mineral. A method for producing synthesis gas using the absorbent is also disclosed.

The process of the present invention provides high recovery and low capital cost giving it an economic advantage over previously known purification processes. The present process has particular applicability to the purification of synthesis gases comprising at least hydrogen (H.sub.2), carbon monoxide (CO), methane (CH.sub.4), CO.sub.2, and H.sub.2O to obtain a gas stream including at least H.sub.2, CO, and CH.sub.4, that is substantially free of H.sub.2O and CO.sub.2. The process also has applicability to the purification of natural gases inclusive of at least CH.sub.4, N.sub.2, CO.sub.2, and H.sub.2O to produce a gas stream including at least CH.sub.4 and N.sub.2, but which is substantially free of H.sub.2O and CO.sub.2.

A system for preheating a pressure vessel includes a throat including an area of excess heat and a dome having an area of deficient heat. The throat includes a conduit extending from a pressure vessel opening to the pressure vessel interior. A plenum is defined between the throat and a seal within the dome. The throat extends from the dome toward a dome floor. The floor is substantially perpendicular to the throat. A conduit is coupled to the plenum and channels a flow of purge fluid into the plenum wherein heat from the throat is transferred to the flow of purge fluid and carried by the flow of purge fluid into the area of deficient heat via a gap defined between the seal and the floor such that the flow of purge fluid reduces temperature differential stresses within the pressure vessel and purges the area of deficient heat.

Plant and process for separation of sulfur-containing components, H.sub.2S, COS and mercaptans from methanol which is used as absorbent within the Rectisol process by hot regeneration of the methanol laden in the absorption and an additional step for separation of the mercaptans from the methanol by stripping.

A process for producing products from biomass comprises pyrolysing biomass at a selected temperature and producing a bio-syngas, processing bio-syngas from pyrolysis step (a) to remove condensable constituents from the bio-syngas, and processing the non-condensable bio-syngas from bio-syngas processing step (b) and producing one or more than one product, such as bio-fuels, bio-chemicals, bio-solvents and bio-plastics.