FR2505808A1 - PREPARATION OF SYNTHESIS GAS FROM HYDROCARBONS RICH IN ASH - Google Patents

Abstract

THE INVENTION RELATES TO A PROCESS FOR THE PREPARATION OF SYNTHESIS GAS BY PARTIAL OXIDIZATION OF HYDROCARBONS WHICH CONTAIN NICKEL AND VANADIUM AT A CONCENTRATION OF APPROXIMATELY 0.01 TO 0.2, WITH THE FORMATION OF CARBON BLACK AS A BY-PRODUCT . ACCORDING TO THE INVENTION, THE OXIDATION OF HYDROCARBONS IN SYNTHESIS GAS TAKES PLACE WITH THE FORMATION OF AN AMOUNT OF CARBON BLACK SUCH AS THE CONCENTRATION OF NICKEL AND VANADIUM IN THE CARBON BLACK TOGETHER DOES NOT EXCEED ABOUT 5 IN WEIGHT, PER REPORT CARBON BLACK, THE CARBON BLACK AND THE ASH FROM THE SYNTHESIS GAS COOLED TO 160-350C ARE SEPARATED IN THE DRY BY MEANS OF A FILTER AND ARE THEN SENT FOR FUTURE USE.

Description

The present invention relates to a method for

  obtaining synthesis gas from hydrocarbons, in particular

  of hydrocarbons rich in ash.

  The transformation of oil into synthesis gas, that is to say the mixture of hydrogen and carbon monoxide, can be carried out according to various processes, which are distinguished by the type of materials used, the oxidizing agents and the reaction conditions The partial combustion of high pressure petroleum has found a particularly wide application for the production of syngas. It is mainly carried out by two processes, which were developed by Texaco Comp, jointly with the Company. Hydrocarbon Res Inc or Shell Comp Company, respectively In both processes, it is formed as

  by-product under normal operating conditions, that is

  to say at 1100-1500 ° C and under 10-40 bar, an amount of about 1 to 3% by weight, based on the oil load, of carbon black, which is separated from the gas by washing at the water, separated from -Ptv and renfronated in general in suspension in oil as ccsttustitle the gasification reactor, or is burned for the

  production of steam, possibly also outside the process.

  Fuel oils (heavy oils), as used in the Texaco process or the Shell process, generally contain

  nickel and vanadium as essential constituents of ashes.

  In the gasification process, they are transformed into Ni S and V 203 and if one ignores small amounts that remain in the reactor, they are discharged with the raw gas stream.

  and separated from the gas simultaneously with the carbon black.

  Most of the vanadium / nickel components are therefore also in the oil / black carbon phase. Only a small part of the process leaves it in suspension in the water.

of the process.

  In a subsequent treatment of the carbon black mixture

  oil independent of the gasification process, for example by combustion for the production of steam in a plant boiler, there is no disturbance in the gasification plant, up to levels up to a total of This procedure presupposes a purchaser for the oil / carbon black phase.

  this can be a disadvantage because the gasification process

  can not operate independently and the treatment of carbon black also requires oil which, for reasons of environmental protection, should generally contain less

  sulfur than the oil used in gasification.

  But the technical difficulties in the gasification already appear if it is necessary to treat an oil having contents of more than approximately 0.01% in nickel and vanadium, the fraction of carbon black must be recycled to the reactor and the sensible heat of the raw gas must be used for the production of steam

high pressure process.

  This last mentioned variant is important, especially in the production of water gases for syntheses, for the production of combustible gases and for the production of

reduction gas.

  The efficiency of waste heat recovery plants, which generally operate in the form of smoke tube boilers, is then adversely affected by deposits.

  nickel sulphide and vanadium oxide are difficult to remove.

  They are closed over time, so that costly cleaning operations related to plant shutdowns are necessary. For these reasons, the gasification of high-grade heavy oils is still completely abandoned today.

in ash and therefore cheaper.

  But it must be reckoned that, in the future, as a result of the progress of the treatment of residual oils in conversion plants, the supply of heavy fuel oil, especially of ash, is becoming scarce. oils with high ash content is not only necessary in the case of the complete use of carbon black for the production of gas The combustion of carbon black also, simultaneously with the oil in the form of black carbon mixture oil in the power plants, could also disappear It was therefore the problem to develop a process for the manufacture of synthesis gas I

  gasification of hydrocarbons, which also allows the use of

  the use of high ash raw materials in a

  gasification plant operating in complete autarky.

  The invention consists of a process for the preparation of synthesis gas by partial oxidation of hydrocarbons which contain nickel and vanadium at a total concentration of about 0.01 to 0.2% with formation of carbon black as under The process is characterized in that the oxidation of the hydrocarbons to synthesis gas takes place with the formation of a quantity of carbon black such that the concentration of nickel and vanadium in the carbon black does not together exceed about By weight, relative to the carbon black, the carbon black and the ash of the synthesis gas cooled to 160-3500 C are dry-filtered off and then sent for use.

higher.

  We can use as raw material according to

  new process any hydrocarbons and mixtures of hydro-

  t 4 f 4 zl Ed S fli: & such as heavy fuel oils or plant residues

transformation.

  The partial combustion of hydrocarbons or hydrocarbon mixtures is carried out according to the methods indicated above as part of the state of the art. A particular characteristic of the new process is the gasification without residue of the oil used, without recycling of the carbon black

  and therefore ashes, as it was usual until now.

  Mainly thereby, also incidentally due to a slightly increased production of carbon black, which takes place in a known manner by controlling the supply of oxygen in the partial oxidation, can be adjusted the nickel content and vanadium in carbon black to a maximum of 5%, value at which there is no

  difficulty due to the deposition in smoke tube boilers

  in the usual way for cooling the gas.

  According to the invention, the formation of carbon black is oriented so that the concentration of nickel and vanadium in the carbon black does not exceed 5% by weight, relative to

carbon black.

  Synthesis gas containing carbon black and ash is cooled to temperatures between 160 and 350 C Cooling is carried out in recovery boilers, which are constructed as smoke tube boilers with velocities relatively high (10-m / s), to avoid solid deposits and, consequently,

  adverse influence on heat transfer.

  The synthesis gas is then sent to a filter on

  carbon black and ash are deposited dry, that is,

  say without using water as an auxiliary phase.

  The deposition of the carbon black is carried out on commercial filters. These filters are used in a form resistant to

  pressure, but also of conventional construction, preferably

  In the form of filter tubes, temperature-resistant fabric filters, such as glass fibers or polytetrafluoroethylene, have been particularly proven. Filters having pore diameters of 15 to 50 am are advantageously used. The gas flow per m 2 of filter area-should be 100 to 350 m 3 / h, the

  loss of charge in the filter layer from 300 to 1000 Pa.

  The carbon black and ash that are precipitated on the filter are advantageously removed periodically from the filter surface with the recycled pure gas. The carbon black obtained can be sent for various uses, depending on the interest. It has proved particularly interesting. reacting the carbon black with synthesis gas in an auxiliary reactor, for example a chamber reactor or a tubular reactor In this reaction, ash is formed which contains all the nickel

  and vanadium of the initial raw material.

  Of course, the carbon black can also be sent to another use, for example to be removed by means of a lock system and used as a load or also to be

transformed as fuel.

  The invention will be better understood on reading the

  description which follows with reference to the single figure of the drawing

  annexed which represents an embodiment of the new method.

  Heavy oil, water vapor and oxygen or air are sent through lines 1, 2 and 3 to a reactor 4 usually under

  high pressure, in which the partial oxidation takes place (i.e.

  The reaction conditions are then adjusted so that the weight ratio (Ni + V) / Is not greater than about 57 The gaseous mixture formed, which consists essentially of CO and H 2 and contains as impurities methane, H 2 S and COS, is sent to a recovery boiler 5 with the carbon black and the ash it contains as solids for the production of high pressure steam which is separated by the pipe 6, and cooled to temperatures up to 'to a little more than the vapor pressure

  saturating Another gas cooling takes place in a preheat

  The feed water 7 is subsequently connected, the final temperatures reached being higher than the dew point (about 1600 ° C.) and less than about 350 ° C., preferably 250 ° C. This is achieved by means of a temperature regulator. 8 which allows to derive

  a portion of the feed water to the preheater.

  The cooled gas is then sent to a resistive filter 9.

  both at the pressure covered with a thermally stable fabric (by axnple fiberglass, polytetrafluoroethylene fibers) To ensure a continuous filtration, several filters (not shown

here) are connected in parallel.

  The carbon black is almost completely deposited on the filter. The filtering surfaces are cleaned periodically by pure gas recycling. The detached carbon black layers fall discontinuously into a lower funnel portion of the filter container. They are very bulky.

(-y-, 150 g / l).

  The carbon black in the dust state is stored intermediately in the lower part of the filter, and from there

  withdrawn continuously via a level regulator 11.

  The pressure difference required for this purpose is produced by braking the pure gas stream in relation to the

  filter resistance by means of a constriction 12 after the filter.

  According to a preferred embodiment, the carbon black in the powdery state is separated with the gas it contains, in a manner corresponding to the average production, and introduced into a small auxiliary reactor 13 which is constructed, for example in the form of a chamber reactor or a tubular reactor In this case, the reaction with oxygen and steam, which are fed via a pipe 21, into synthesis gas The additional synthesis gas stream is sent with the liquid ash through a pipe 14 to the container 15 which is supplied with water by a pipe 16 The stream of synthesis gas is cooled suddenly by the water and washed in the container 15, which separates in particular

  the liquid ash present in small quantities.

  The ash components of the oil are removed in the form of fine shots together with the water, either continuously or discontinuously, via a lock system which is

  controlled by a regulating system 17 and subsequently separated by.

  usual separation devices (eg decanters, filters).

  The purified gas is separated by a pipe 18 A part of the pure gas is recycled in the case of a continuous filtration process to the filter 9 by a pipe 19 by means of a blower 20 During the purification process, the filter 9 not used, it is replaced

  by one of the filters connected in parallel.

  In the case where the carbon black has to be sent to another use than the gasification process, it can be

  removed from the system dry or resuspended in water -

by means of pressure locks.

  It is understood that the invention is not limited to the preferred embodiments described above by way of illustration and that

  those skilled in the art may make various modifications and changes

  without departing from the framework and spirit of the invention.

tion.

Claims (3)

R E V E N D I C A T IO N S   Process for the preparation of synthesis gas by partial oxidation of hydrocarbons which contain nickel and vanadium at a concentration of about 0.01 to 0.2%, with formation of carbon black as a by-product, characterized in the oxidation of the hydrocarbons to synthesis gas takes place with the formation of a quantity of carbon black such that the concentration of nickel and vanadium in the carbon black does not together exceed about 5% by weight, compared to the black hole of carbon, dry is separated by means of a carbon lenoir filter and the ash of synthesis gas cooled to 160-3500 C and then sent for later use. Process according to Claim 1, characterized in that   filters consist of fiberglass or poly- tetrafluoroethylene.   3 Process according to claims 1 and 2, characterized   The filters have a pore diameter of 15 to 50 μm.   Process according to claim 1, characterized in that the carbon black separated to dryness is converted into synthesis gas in an auxiliary reactor.