DD150600A1 - METHOD AND CATALYST FOR THE RE-BURNING OF BY-PRODUCTS FROM PARAFFIN OXYDATION - Google Patents

Abstract

The invention relates to the catalytic afterburning of the waste products obtained in the paraffin oxidation. The aim of the invention is the elimination of odor pollution of the environment by waste products of paraffin oxidation with simultaneous use of Abwaerme. According to the invention, this is achieved by passing the exhaust gas over a catalyst combination consisting of noble metal catalyst or dilute noble metal catalyst and base metal oxide catalyst.

Description

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TITLE OF THE INVENTION

Process and catalyst for the afterburning of waste products

AFWEKDUITGSGEBIET DER ERFIM) UKG

The invention relates to a process and a catalyst for the catalytic afterburning of the high-energy polluting waste products resulting from paraffin oxidation.

CHARACTERISTICS OF COMPATIBLE TECHNICAL SOLUTIONS

With the DD 108 220, it was proposed to supply the post-combustion plant with energy from outside the entire system and to deliver the heat energy directly into the recirculation loop.

With DE 1 264 671 it has been proposed to coat the heating elements of an IT after-combustion plant with a catalytically active mass. This solution presupposes that electrical heating elements are arranged both before the catalyst and during the afterburning.

Due to the significant energy supply from outside the system as a whole, these two solutions are not economically effective. "

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It is also known, for the oxidation of organic substances as catalysts to use noble metals or base metal oxides, which are applied to metallic or ceramic substrates. Precious metal catalysts operate at a relatively low operating temperature and have a relatively high efficiency "With a high proportion of combustible in the exhaust but occurs high thermal contact load. By adding fresh air, this contact load can be reduced, but this is the other hand, especially with fluctuating attack of combustibles in the exhaust, the risk of blowing out of the reactor and also due to the lowered exhaust gas temperatures, a potential waste heat recovery ineffective.

The experiments carried out with base metal oxide catalysts showed that only at a Vormwärmtemperatur of the exhaust gas above 350 ° C, the efficiency is above 90%. And this is necessary for a high temperature level to be achieved in the system

Also in this solution, it comes to high thermal loads on the reactor and the entire liachverbrennungsanlage. In addition, the variations in the provision of combustible components due to batch operation can not be compensated for, e.g. the ignition temperature can be fallen below. There is no stable driving.

OBJECT OF THE INVENTION

The aim of the invention is to economically burn the waste products contained in the exhaust air of the paraffin oxidation and thereby simultaneously to minimize the odor nuisance of the environment by reacting the odor-causing components in COg and HgO _e

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DARLEGMG OF THE CREATION OF THE ERPIBDUNG

The object of the invention is to propose a process and a catalyst in which waste products of paraffin oxidation, which occur batchwise in batch operation, can be incinerated with minimal energy expenditure while optimally utilizing the waste heat for other processes while largely keeping the thermal load on the plant.

According to the invention, a partial exhaust gas stream of paraffin oxidation is preheated to 16O-200 ° C. and passed through an ignition charge of a noble metal catalyst or via a noble metal catalyst charge diluted with pure contact support material. The temperature increases to over 350 ° C. Subsequently, this first partial gas stream is passed over a bed of a base metal oxide catalyst and almost completely oxidized * By mixing a second cold gas stream, the temperature is lowered again to about 350 ° C. The total gas flow is now through the third bed, which in turn consists of a base metal oxide catalyst, out · The ongoing oxidation has an efficiency of about, 90 % . By optional subsequent connection of a noble metal catalyst bed diluted with pure contact carrier material, an efficiency of the system of more than 95 % is achieved and an almost odor-free exhaust gas is produced.

With a very high proportion of combustible substances in the exhaust gas, it is expedient to subject it to partial condensation before it is passed through the catalyst combination.

According to the invention this is further achieved by combining a base metal oxide catalyst, preferably an iron oxide (Fs ^ Or ^) ^ -toner based catalyst, with a noble metal catalyst, preferably a platinum catalyst, such that at least two base metal oxide beds a Zündschüttung a noble metal catalyst or with

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pure contact carrier material diluted noble metal catalyst is introduced into the reactor and that after the two base metal oxide beds optionally still one with pure contact carrier material diluted noble metal catalyst bed is introduced into the reactor *

This method and the catalyst combination have the advantage that only in the start-up phase of the reactor energy must be supplied from outside the system to bring the exhaust gas to a maximum temperature of 180 - 200 C. As a result, partial oxidation of the waste products is already achieved in the ignition charge. "The relatively large bulk material of the base metal oxide catalyst stores a certain amount of heat in the operating state, and at the same time acts as a regenerator. This compensates for fluctuations in the heat balance.

AüSFUHRUNGSBEISPIEL

The resulting in a discontinuous batch process at the Paraffinoxydation waste products (50 g / m) occur as the exhaust gases, the fatty acids, ketones, aldehydes, inter alia, contain a temperature of ca _e 80 ° C from the reaction vessels, in which the oxidation is carried out from. In a plate heat exchanger, a partial exhaust gas stream is heated to a maximum of 180 - 230 ° C and passed through a 5 cm thick bed of platinum contact having an ignition temperature of 16O - 180 ° C «In this serving as a spark plug platinum contact bed a Teiloxydation this partial exhaust gas stream, which is associated with a temperature increase to over 400 ° C. In the first bed of the iron oxide catalyst CFe ₂ OO <g-based on clay, the complete oxidation of the first partial exhaust gas flow is carried out. This fully oxidized hot partial exhaust gas flow is now between the first and second bed of the

Iron oxide catalyst zugeffiischt a second cold partial exhaust gas stream and fed this total exhaust gas flow of the second Scliüttung. The complete oxidation of the combustible constituents of the partial exhaust gas stream fed in between the first and second bed takes place at a temperature which is still above 400 ° C. Thereafter, the total exhaust gas stream is passed over a dilute platinum contact bed, thereby increasing the efficiency of the process by a further 5% % increased,

After starting up the system, it is no longer necessary to heat the exhaust gas by external energy supply ₉ but this heating can be done by means of the energy released during the oxidation.

By appropriate control of the exhaust, partial exhaust and fresh air streams, it is possible to drive the system so that daa temperature level of the post-combustion system is optimally maintained and maximum utilization of the waste heat canv

By the proposed method and the catalyst combination, the following advantages are achieved:

~ Complete combustion of waste products contained in the exhaust gas

- Lowering the thermal load of the reactor

- Minimal energy consumption in the start-up phase and short heat-up time

- Use of waste heat

- Relatively low catalyst costs compared to the use of pure Edelmetallscliüttungen

Stable travel relatively independent of the achievable preheating temperature

- No influence on the ITach combustion process due to batch operation in paraffin oxidation »

Claims (5)

ERFIKDUITGSANSPRUOH 1 * ¹ A process for post combustion of waste products from the Paraffinoxydation characterized in that the exhaust gases of an Paraffinoxydation a Katalysa "· gate combinations of a noble metal catalyst can be performed with a base metal oxide catalyst by a partial exhaust gas stream of a Paraffinoxydation to 160 - preheated 230 ° C, via an ignition charge of a noble metal oxide catalyst or via a noble metal catalyst charge diluted with pure contact support material and then passed through a bed of a base metal oxide catalyst, mixed with a cold gas stream a base metal oxide catalyst bed and subsequently optionally a noble metal diluted with pure contact support material Catalyst feed is fed * 2 * method according to item 1, characterized in that the exhaust gas, before it is passed over the catalyst combination, is subjected to a partial condensation, 3 * Catalyst for the afterburning of the by-products of a paraffin oxidation characterized in that it consists of a combination of noble metal catalyst and base metal oxide catalyst _o ^L s <& i IU / 4 * catalyst according to point 3 characterized by. that the noble metal catalyst is a catalyst of the platinum group. 5 · 'catalyst according to item 3 dadurcii _y that the base metal oxide catalyst, preferably FeJ ^ -i% on an iron oxide catalyst - ~' TonerdebasiB, and in that at least zv si beds available s?