DE3424974A1 - Process for improving the efficiency in the purification of flue gas, for example by the "scrubber principle" - Google Patents

Abstract

An improvement with regard to the efficiency in combination with reduced environmental pollution can be made possible by first recovering fertiliser or improved building materials, such as high- grade gypsum, in a known manner from flue gas wastes, in particular from SO2 and NOx, and connecting downstream of such a process a stage for CO2 liquefaction which in turn, following a special process by impregnation of irrigation water, is used in fertilisation, as a result of which an elevated yield increase is possible in all application areas with all ornamental and economic plants. At the same time, an improved nutrient uptake by the plants is possible by the novel process, as a result of which soil leaching and inputs into the ground water are reduced. Since atmospheric pressure and atmospheric gas distribution and thus also the Gay-Lussac law prevail in the top soil layers, gas exchange is promoted by supply of CO2 and thus the oxygen supply to the roots is improved and the soil is also loosened by nitrogen aeration.

Description

"Process to improve profitability in

Purification of flue gas, e.g. according to the "scrubber principle" "The invention relates to a method for cleaning flue gas while recovering usable substances from the exhaust gas. Flue gas cleaning and recycling of waste materials are according to the status of technology primarily an economic problem, less a problem of technical solvability.

The soon unavoidable redefinition of reduced Emission values either require large investment costs for the polluters, or, in the final analysis, a difficult burden for them to cope with Population.

The pollutants are primarily sulfur dioxide and nitrogen compounds. Large-scale systems are currently being developed in Japan and the USA and used with the aim of reducing the air pollution with pollutants drastically to reduce and at the same time with this principle Waste products to win that can be used as recyclable materials. This will make the Improved efficiency of the cleaning process. One in America and Japan Developed principle for the elimination of sulfur dioxide and nitrogen compounds is known as the "scrubber principle" and assumes that through Injecting water, flue gas is cooled from approx. 1500 to 70 to 9000.

Then ammonia (NH3) is added and in one so-called electron beam reactor to oxidation and reaction by bombardment an ammonium sulfate (NH4) 2SO4 or

to a mixed salt ammonium nitrate sulfate. These mixed salts can as tests have shown, can be used as fertilizers. Other developments go there through the improved excretion of sulfur dioxide and nitrogen compounds To produce high quality building materials, especially high quality plasters.

These processes produce around 90 to 100% sulfur and nitrogen oxides eliminated and thus the exhaust gas pollution of the air significantly reduced, in particular if one takes into account the huge amounts of exhaust gas that is produced in electricity and steel mills. What remains are residual gases in which other parts of the flue gas are contained in enriched quantities.

So with all of these considerations to remedy the triggered Environmental damage does not take into account the damage through stress enters the air with carbon dioxide. This remains with the procedures mentioned, e.g. according to the "scrubber principle", practically unrestricted in the residual smoke gases discharged return. Carbon dioxide is an almost inert, inert gas, which is directly none triggers recognizable damage, but indirect processes of fundamental nature in the soil Of importance for the growth and health of plants. In addition, a C02 atmosphere fertilization> for example in glass houses, to significant increases in yield to lead.

Tests have clearly shown that an additional yield of up to 50% Direct gassing can be achieved (see Chemistry Lexicon ~ Römpp "> Page 1811, carbonic acid fertilization). If the carbon dioxide is introduced directly into the ground via irrigation water, a same benefit with greatly reduced use of CO2, i.e. much more economical will.

Since poor soils are made fertile by mineral fertilization, was the supply of the earth's population since the beginning of the fertilization method by Justus von Liebig improved considerably over the past century. Due to lack or decrease of organic substances is no longer the same as the amount of CO2 produced guaranteed in the ground. The result is that although the fields bring high yields, but the plants themselves are sick and susceptible to pest infestation. on the other hand arises from burning the fossil, solid, liquid and gaseous Fabrics a high accumulation of C02, which does not benefit the flora, but through the Atmosphere escapes into the troposphere. This creates the troposphere, which acts as a climate belt responsible for the habitability of our planet, with high concentrations loaded with C02. While in the past century with increased CO2 concentrations Absorption by rainwater is responsible for the transport of the CO back to the earth today this return transport is insufficient. Through human intervention is thus one CO2 depletion in the soil and an overconcentration in the troposphere occurred, without the former being able to be counteracted and the latter being dismantled so far, because SO2 in particular blocks the absorption power of rainwater in relation to CO. About 0.88 1 C02 can be absorbed for 1 1 condensate, compared to 40 1 SO2, i.e. almost 50 times as much as SO2 (see Römpp, Chemie-Lexikon, page 1989, 1st column, Lines 17 to 20). This fact favors the so-called "acid rain".

In the climate belt, H2O and C02 mainly have to ensure that the solar energy radiated during the day does not enter space at night flows back, while during the day the same protective belt for a flora and fauna compatible Climate ensures. Without this protective belt, temperatures can be around -180 ° C at night and during the day are + 100 ° C, i.e. all life would be impossible on our globe. It is not only the temperature compensation that is decisively influenced by the C02 content, but at the same time there is also an influence on the condensation points for the Rain formation. Excessive concentrations will also affect this strongly influenced the climatic conditions on earth. This will be indirect damage be even greater than those that previously occurred through direct environmental pollution are.

It is the object of the invention to contribute to this development A halt is required by not only recovering SO2 and NO x from the exhaust gases can be used, but also the carbon dioxide, in an economical way Way. In terms of fertilization, this would be extremely advantageous for all soil crops be. At the same time, however, such a procedure would contribute to the sophisticated Supporting nature's circulatory system instead of destroying it.

According to the invention, this object is achieved by the teaching of the claim solved.

It is assumed that the degree of purity customary in the trade for CO need not be adhered to by over 99.9%.

A liquefied CO2 application for medical and beverage purposes is - at least initially - not intended. This will increase the profitability increased, while the now achieved manure production considerably, also economically, is improved. For example, about the use of CO2 obtained in this way more fluid Making the form usable as a fertilizer for outdoor crops is expedient a process is provided that makes it possible to have a high gas content in a CO2-impregnated To keep water bound. A suitable method is e.g.

Subject of the European patent application 84101115.4.

The previous methods for the elimination of sulfur and nitrogen oxides, e.g.

the "scrubber process", significantly more economical. Simultaneously will drastically reduce environmental pollution and improve climatic conditions initiated.

In contrast to a study of the German Society for Mineral Oil Science and Coal Chemistry also economically used to increase the yield in oil deposits through floods of carbon dioxide because the nitrogen fertilizer production, in contrast to the study, the CO2 content does not degrade if e.g. the American / Japanese method with electron bombardment is used.

The impregnation process according to the aforementioned European application provides for the fine impregnation of a liquid with CO 2 gas that the to be impregnated Liquid with the pressure of 1 bar prevailing in the respective pipe system upwards at predetermined points in the pipe system with the CO2 gas Underpressure or reduced compared to the system pressure pressure is brought into contact. A series of injector nozzles is provided for this purpose which the liquid with an abrupt decrease in the flow rate guided and at the same time in the injector stage by partial reduction of the Liquid pressure the water with the C02 gas by suction and pressure difference (Gas pressure / water pressure in the partial areas) is brought into contact, wherein the pressure in the gas impregnation chamber is also the delivery pressure and so with the line pressure is identical, practically at any dispensing point.

By applying a low impregnation pressure, an otherwise The usual compression of the gases is avoided, and so are the expansion losses low for use in outdoor crops.

The invention can be used in connection with all methods with which sulfur and nitrogen oxides without any significant reduction in the CO2 content economically removed from flue gases and processed into usable waste products can be.

Claims (1)

-Patent claim process for cleaning flue gas and for extraction of usable waste materials, d u r c h e k e n n -z e i c h n e t that initially the C02 content of the flue gas is enriched in a first stage in that from the flue gas sulfur and nitrogen oxides, e.g. according to the scrubber principle in the form largely excreted of economically reusable substances, e.g. salts whereupon the CO2-enriched residual smoke gases or the contained therein Liquefied C02 and used to impregnate irrigation water and / or fertilizer liquid will.