CS243382B1 - Method of hydrogen production - Google Patents

Abstract

A method for producing a worm from a generator gas from petroleum and tar gasification oxygen and water partial oxidation residues; high-temperature combination and low temperature carbon monoxide conversion d water vapor and carbon dioxide scrubber in j two stages using an aqueous solution of the technology triethanolamine according to the invention in that it is in the generator gas before by entering high temperature conversion the content of iron and nickel carbonyls such that I the pretreatment generator gas saturates at I 80 ° C to 100 ° C water vapor and treats I at a temperature of 170 to 250 ° C via passage I alumina cartridges and, after conversion, I carbon dioxide is washed with an aqueous solution of technic-1 triethanolamine with the addition of an activator; \ t e.g., 1.6 diaminohexane at 0, 1 to 1 15 S weight.

Description

(54) Method of producing hydrogen

I í

A process for producing hydrogen from a generator gas obtained by gasifying petroleum and tar residues by partial oxidation with oxygen and water ^; with steam, a predominant combination of high-temperature and low-temperature carbon monoxide conversion by steam and carbon dioxide scrubbing in two stages using an aqueous solution of technical triethanolamine consists in reducing the carbonyl content of iron in the generator gas before entering the high temperature conversion; nickel by soaking the pre-gas generator gas at 80-100 ° C with water vapor and treating it at 170-250 ° C by passing through 1 alumina cartridges, and after conversion, the carbon dioxide is scrubbed with an aqueous technical solution. triethanolamine with added activator, for example 1.6 diaminohexane in an amount of 0.1 to 1.0

With weight. AND

and

243362 2

The invention relates to an increase in hydrogen production from generator gas obtained by gasification of petroleum and tar residues by partial oxidation with oxygen and steam, pre-treatment and generator gas, and high and low temperature conversion of carbon monoxide by steam with subsequent carbon dioxide scrubbing.

In the gasification of petroleum and tar residues by partial oxidation with oxygen and water vapor, a raw generator gas is obtained, which is the starting material for the production of hydrogen and for the production of synthesis gases intended for the synthesis of ammonia, methanol, olefin oxonation and the like.

The raw generator gas exiting from the pressure generators operating, for example, at a pressure of 3.5 MPa, is first freed of the carbon blacks contained therein by means of a pressurized water scrubber and in the next technological stage the hydrogen cyanide, hydrogen sulfide and carbonylaulphide are removed.

It is customary for such a pre-purge generator gas to be free of sulfur compounds to a value of less than 25 mg / m 2.

Technical hydrogen and synthesis gases are recovered in the necessary technological stages from the generator gas treated in this way. If the proportions of hydrogen and synthesis gases produced by the project and established in practice are confused, eg at stoppages, when production is limited or production is decommissioned, eg methanol, it is necessary to limit the total production of gases resulting from the pre-purged generator gas.

This is disadvantageous from an economic point of view and therefore considerable efforts have been made to utilize the total generator gas production capacity and to increase hydrogen production with limited synthesis gas production.

However, an increase in hydrogen production from another preconverted gas generates a higher load on the high-temperature and low-temperature conversions, carbon dioxide scrubbing, and methanization of residual carbon and carbon monoxide to less than 10 ppm vol.

By simply increasing the throughput, the planned and operationally acquired production volume cannot be increased.

It has now been found that it is possible to increase the production of hydrogen without major interventions in the existing plant and without any investment-intensive modifications. A process for producing hydrogen from a generator gas obtained by gasification of petroleum and tar residues by partial oxidation with oxygen and steam, pre-treatment, combining high temperature and low temperature carbon monoxide carbon monoxide conversion with carbon dioxide scrubbing in two stages using an aqueous solution of technical triethanolamine in the generator gas, the iron and nickel carbonyl content is reduced by min. 50% compared to the present state, where the pre-treatment gas contains 3 to 5 mg / m ^ Pe and 1 to 5 mg Nt / m ^, i.e. to 1.5 to 2.5 mg Fe / m and 0.5 to 2.5 mg Ni / m ^ by saturating with water at 80 to 100 ° C and treating it at 170 to 250 ° C by passing through an alumina cartridge, and carbon dioxide is washed in two after high and low temperature conversions. % of an aqueous solution of triethanolamine to which an activator of 1.6 diamohexane in an amount of 0.1 to 15% by weight is added.

A reduction in the iron and nickel carbonyl content of the pretreated generator gas prior to entering the high temperature conversion is necessary to ensure that, when the generator gas throughput is increased, a suitable conversion of carbon monoxide throughout the working cycle, e.g.

months.

In the pretreated gas generator, the carbonyl is present, for example, in an amount of 3 to 5 mg Fe / m 2 and 1 to 5 mg Ni / m 2. These carbonyls decompose in the high-temperature conversion apparatus and penetrate the top of the filled catalyst catalyst, resulting in a progressively deteriorating activity, an increase in the residual carbon monoxide content of the outgoing gas, and an increased pressure drop in the conversion reactor.

With increased throughput of generator gas, these problems will occur sooner and this may!

lead to shortening of the usual duty cycle. These problems can be avoided by incorporating the removal of iron and nickel carbonyl groups min. of 50 ·. (

As stated above, the iron and nickel carbonyl content of the installed equipment can be reduced

for the purification of the carbon black-free generator gas and for the hydrolysis of the carbonyl sulphide j on the alumina fill. j

Carbonyl sulfide hydrolysis is generally carried out at 150 ° C and the generator gas is still steamed at a temperature of about 75 ° C and a working pressure of about 3.15 HPa. As has been verified, in addition to the desired hydrolysis of carbonyl sulfide, a significant reduction in the contained iron and nickel carbonyl can be achieved if the working temperature is raised from 150 ° C to a temperature of 150 ° C.

170 to 250 ° C.

In order not to compromise the hydrolysis of the carbonalsulfide, the generator gas can be saturated with water vapor at a higher temperature than previously maintained at 75 ° C in the choke, at temperatures in the range of 80 to 95 ° C, possibly even at a higher temperature.

At an elevated temperature of 170 to 250 ° C, the iron and nickel carbonyls present are largely decomposed and solids are collected in the reactor for the pre-scrubbing of the generator gas and partly also in the reactor in which the hydrolysis of carbonyl sulphide to hydrogen sulfide and carbon dioxide is completed. . ί

The solids from the decomposed iron and nickel carbonyls separated on the reactor charge to pre-purge the generator gas deteriorate the process gas throughput and therefore it is desirable to grind and remove the resulting crust dsad.

This reactor is taken out of operation while the other equipment remains in operation. After cooling and flushing, the daads are removed and, if necessary, the charge is refilled, such as a cobaltaolybdenum catalyst, possibly partially deactivated, or aluaine, etc., the reactor is again brought into operation.

Annually it is possible to perform this operation for example 3 times.

Example i

The carbonylsulfide hydrolysis plant, which consists of two parallel lines, has been modified in one operating line to increase the working temperature from the usual 150 ° C to 210 ° C while increasing the dew point of the gas at pressure |

3.05 MPa from 75 ° C to 85 ° C.

and

To increase the working temperature of the gas, a new heat exchanger with heat exchanger (area 160 and ² ) has been incorporated, utilizing the heat of the exiting gas to heat the incoming gas. T each operating line has two charge reactors suitable for carbonyl sulphide hydrolysis. the main component being aluminum oxide.

in both lines the same. and

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The composition of the incoming gas to both lines was as follows:

co ₂ 4.2 »mol. what 45.8 * aol. »2 48.8 »aol. iaerty 1,156 frmol. M 0.014 frmol. what with 0.03 fr aol.

The carbonyl content of Po and Mi, expressed in mg Pa and Mi per £:

Fe 2,3

Ni 4,1

The effect of the change of technological regime was compared with the operating line, which operated in the current way. The results were as follows:

Technology mode

Existing According to the invention - process gas load (® ^ / N) 72 000 72 000 - working pressure (KPa) 3.15 3.15 - temperature of gas at the entrance to hydrolysis reactors (° C) 150 210 - water vapor content of the feed gas '"IT 0.013 0.024 - the carbonyl sulphide content at the outlet from hydrolysis reactors (ppm vol). 0.7 0.7 - process steam consumption per 1000 m ^ of input gas (kg) 41.6 55.5 - <Fe and Ni carbonyl content of the off-gas expressed as mg / m 2 Fe 2.2 0.7 Ni 3.95 0.4

It is evident from the stated analytical values that after the increase of the working temperature there was a significant decrease in the carbonyl content. With this reduction of the iron and nickel carbonyl groups in the generator gas, the high temperature conversion section can be operated with satisfactory results throughout the working cycle, e.g., 18 months.

The existing high temperature conversion reactors were charged with 30 m @ 3 of the combined charge. Compared to the present state, the proportion of more active conversion catalysts has been increased at the expense of a catalyst with lower activity.

The conversion process and the results obtained are shown in Table 1.

Table 1

original state reduction of Fe and Ni carbonyl 50% at 90 « - amount of dry gas to conversion (m ^ Zh) 60 000 65 000 65 000 - CO input content (% vol) 46.5 46.5 46.5 - water vapor content m na per m m of feed gas 1.02 to 1.12 1.00 to 1.10 0.97 to 1.1 - amount of catalysts filled (m ^) Cherox 3607 5 5 5 K 6-10 17 20 May 25 Charox 3100 8 . 5 - - cartridge life and cycle life outages 1st stage reactor (months) 18 18 18 2nd stage reactor (months) 36 54 54 - the cost coefficient of the catalyst charge for both stages 1 1.05 1.12 - the cost coefficient of the catalyst charge

for both degrees, calculated for longer cycles (months) 1

- the gas inlet temperature to the reactor 1 ... degree at the beginning of the cycle (° C) 290 at the end of the cycle (° C) 325

- CO content at the outlet of the 2nd conversion stage (* vol.) 4,0

0.93 0.62

292 292

320 330

4.0 4.0

In the low-temperature conversion section, 20 conversion catalysts were fed into the existing reactors as shown in Table 1. After the addition of the activator to the scrubbing liquid during the carbon dioxide scrubbing, the hydrogen sulphide content of the effluent from the first stage of the scrubber decreased from 52 ppb to 23 ppb, and this has been shown to reduce irreversible deactivation of the filled copper-based low temperature catalyst.

When selecting the catalyst charge, it is necessary to take into account the availability and price range of individual catalysts. Compared to the hitherto usual situation, catalysts have been filled, which can be expected to run for up to three years with sufficient operational reliability for the working period.

In the first case of intensified production, for example, the catalyst KTK 4 was filled, which, due to its lower zinc oxide content, has a lower resistance to catalyst poisons.

After 18 months of operation, 40% of the catalyst charge was replaced with the same amount of the catalyst ICI 52-1 and after its reduction, the combination was operated for another 18 months. In the second case of intensified production, the catalyst ICI 52-1 was filled, allowing it to operate for 36 months. j

The conversion process and the results obtained are shown in Table 2 below.

Table 2 initial state intensified operation case 1 case 2 amount of dry gas to conversion

(m ^ / h) 60 240 65 060 65 060 input CO content (* vol.) 5.42 5.42 5.42 water vapor content m ^ to m ^ input gas 0.28 0.30 0.26 catalyst charge (m +) C 18 HC 20 May - - NTK 4 - 20 mm (12) - ICI 52-1 - - (8) 20 May lifetime of the filling of the month 24 36 36 catalyst coefficient refills 1 0.9 1.17 catalyst coefficient cartridges calculated per duty cycle 1 0.65 0.78 output CO content at the beginning and at end of cycle (* vol) 0.37 to 0.41 0.38 to 0.46 0.36 to 0.41 For intensification of hydrogen production it is necessary to increase working capacity for oxygen filling carbon dioxide, which is carried out in two stages. It was found that to increase working

capacity is achieved by using the 30 to 35% aqueous solution of technical triethano

243382 6 laminate adds activator. A suitable activator is, for example, 2.6 diaminohexane added in an amount of 0.1 to 15% by weight. For practical application, it is important that the efficacy of the wash liquid with the activator allows the amount of wash liquid to be reduced while maintaining approximately the same hydrodynamic load on the absorbers even with increased hydrogen production.

For operational applications, it additionally requires that the added activator does not increase the corrosive action of the circulating wash solution or reduce the corrosive action of the circulated wash solution. Tests have shown that for example 1,6 diaminohexane meets these two requirements.

Claims (1)

P & SSUSX OF THE INVENTION A process for producing hydrogen from a generator gas obtained by gasification of petroleum and tar residues by partial oxidation with oxygen and steam, pre-treatment, by combining high temperature and low temperature carbon monoxide carbon monoxide and carbon dioxide scrubbing in two stages using an aqueous solution of technical triethanolamine. of gas before entering the high temperature conversion reduces the carbonyl content of iron and nickel to 1.5 to 2.5 mg Fe / m 2 and 0.5 to 2.5 mg Ni / m 2, so that the amount of carbonyl is reduced. the pre-refined generator gas is saturated with water vapor at 80 to 100 ° C and treated at 170 to 250 ° C by passing through an alumina charge and after conversion the carbon dioxide is scrubbed with an aqueous solution of technical triethanolamine with the addition of an activator such as 1,6 diaminohexane in an amount of 0.1 to 15% by weight.