Birkeland-Eyde Process Information In Critical Thinking

2.2. Theory

This is a historical study using methods borrowed from the history of science and ideas. This means that the relevant parties' and stakeholder's views of, and attitudes towards, forests and forest fertilization were the primary object of the study, as opposed to forests and forest fertilization per se [16]. It also means striving to define differences of opinion in a symmetric and neutral way, so that different perspectives are brought to light.

On the theoretical level, the study has been inspired by Johan Asplund's heuristic model for idea-critical research. This model is based, in part, on the ideas of the Annales school on mentalities, such as ingrained thought structures, and on Michel Foucault's discourse theory, but it also draws on the Marxist theoretical framework of base and superstructure [15,17,18]. One of its central concepts is “figures of thought” [15].

A “figure of thought” is, briefly defined, a persistent idea which more or less implicitly influences the way people understand their surrounding world [15,19]. This definition might fit as well for some interpretations of the theoretical concept of “discourse” [20]. In Asplund's version, however, figures of thought and discourses have different properties. Discourses are shorter-lived and more volatile than figures of thought and any number of discourses may exist at any one time. Figures of thought, on the other hand, are persistent and fewer in number. Only a small number of figures of thought exist within a single age and culture. A figure of thought is resilient inasmuch as it is able to survive even rapid and violent changes in the base, i.e., in the material conditions of a society, and remain primarily intact, or, at most, only partially altered. Figures of thought are, however, not assumed to be eternal. Although multiple figures of thought may be present in a society at the same time they may also cause conflicts between people who hold on to incompatible figures of thought [15].

Additionally, figures of thought are characterized by the fact that, as a rule, they are unspoken by those parties or groups that hold them. The complex of attitudes contained in the figure of thought first reveals itself as explicit ways of thinking at the discursive level, i.e., in the arguments and values expressed in a debate [15].

Asplund posits that research into the history of ideas has so far revealed only a limited number of “real” figures of thought [15]. Some examples of these are the idea of progress; the idea of existence as a great series or chain of being; and the idea that the earth has a limited lifespan, that it is ageing, deteriorating, and approaching its own demise. Each of these main ideas is considered to have been especially influential, i.e., to have dominated discourses in previous centuries. The idea of the ageing of the world—the idea of decay, or mundus senescens—was very prominent during the 1600s, while its antithesis, the optimistic idea of progress, dominated the 19th century. By way of contrast, the 18th century was characterized by the idea of the great chain of being, which according to Asplund found expression in Linnaeus' work on the classification and systematization of plant and animal species [15].

These real figures of thought have also played a role in the way people (at least those in the Western cultural sphere) have formulated conflicting expressions about nature and the future, and they remain with us to this day [15]. In this study, we will demonstrate how the real figures of thought influenced the debate about forest fertilization during the 1960s and 1970s. We will also examine and discuss the way they continue to color present-day debate concerning intensified forestry, including increased fertilization.

To give further guidelines to the reader we present definitions of these figures of thought as they will appear in this article. As we understand them, both from our own analysis and from previous research, the three real figures of thought, as presented by Asplund, or “transformations” [15] of them, have been constituted as follows during the last six decades: “The idea of progress” has represented faith in humanity's ability to increase and process the earth's resources. It thus implies that mankind has supremacy over nature. It also implies that the future will always be brighter than the past as long as we develop new technology and foster economic growth. Previous research has strongly connected these ideas to the mid 20th century, especially to “the happy 1950s” (e.g., [21-24]).

In the 1960s, i.e., the time for the awakening of the modern environmental movement, the idea of progress faced new competition from “the idea of decay”. Previous research often assigns the modern breakthrough of this figure of thought to the Club of Rome and the presentation of their study The Limits to Growth in 1972. In contrast to the idea of progress, this figure of thought turns the spotlight on concerns about the earth's limited resources and the survival of the planet. It implies that humankind should adapt to nature's resources and circumstances. Adaptation, not supremacy, is thus a key concept [22,24-26].

The transformation of the idea of the great chain of being is not as obvious. According to Lovejoy (1936) this idea was a dominating figure of thought before the theories of evolution were presented in the 19th century [27]. Today there is a similar metaphor in ecological theory, in which everything existing is situated within complex ecosystems. These “chains” or systems of being are, however, seen neither as hierarchical nor static structures as they were in pre-modern times [28]. As this article will show, we have found that the conflicts in the environmental debate concerning intensive forestry and fertilization are mostly between agents of the progressive figure of thought and the decay figure of thought. The idea of the great chain of being has been somewhat intertwined with both of the other two figures but most of all with the idea of decay [29].

IMHO a critical problem with the Birkeland-Eyde is the low conversion of air, resulting in low concentrations of NO2 and problems with efficiently condensing/reacting the very dilute product.

This patent is a major step forward for small scale nitrogen fixation.

Silica gel in a ~1% NO2 atmosphere at 15C will hold 6.5% by weight NO2 at equilibrium. According to the patent, in practice ~4-5% is the concentration achieved with 5% loss of NO2 through the bed of 10-14 or 6-8 mesh silica gel. They say with a silica gel bed 3 feet high, and flow velocity of 100 ft/min, 100% of the NO2 is caught for 12min then efficiency drops off till it is catching 75% after 30min. They say at this point the silica gel is 75% saturated, which I assume means 4.8%NO2. Over the 30min a total of 5% of the NO2 is lost through the bed. If the granular fill factor is .4 (slightly fluidized) and the silica gel has 1ml/g pore volume, the silica gel loading would be 22kg/sq ft of bed, which corresponds well at 4.8% NO2 to the ~1kg of NO2 that would be carried by the corresponding 50 cubic meters of 1% NO2 (calculated as pure monomer) that flow over 30min. I think the patent was calculating the NO2 content based on the original NO% by volume.

In the process they use, three silica gel beds are alternated between, so that they have 30min to reach full capacity, 30min to extract the NO2, and 30min to cool down. 75% of the NO2 content as 98% pure gas is extracted at 165C, then 180C air is blown in to pull out the remaining 25% as a ~20% mix with air (which is made into HNO3). This way they would need 500-600kg of silica gel sorbent in the cycle to process their NO synthesis furnace output of 375mol/hr NO. Thus with 900 cubic meters of air, 27 kg hydrocarbon fuel (enough to use up 38% of the O2), they are able to get 12kg liquid N2O4, 6kg HNO3, and 250-300 kwh usable heat energy per hour. That comes to 68 kwh per kg of N fixed. This is better than the original Birkeland-Eyde process, and only about 2-3 times the current state of the art plasma 10^8K/s quench rate N fixation systems. When you take into account the efficiency of electrical generation/transmission, using fuel starts to look even more attractive.

For the very small scale experimental N fixing system, no doubt a plasma system would be simpler than a scaled down version of this patent. Not having to meter fuel/air, cool and dry exhaust gasses, etc would make the entire thing very simple. All you'd need is an air pump, an air drying tube, a plasma reactor run by TV or neon sign transformer, and a silica gel chamber. Once silica gel is near saturation, shut down the plasma reactor and use the NO2/silica gel as you please. It is safe convenient to store NO2 in silica gel. It can added directly to a reactant as a more mild nitrosating or oxidizing agent than liquid NO2. It can obviously be reclaimed as pure NO2 gas upon heating. I can't find any refs that mention NO2/silica gel + ozone, but interesting things may happen if you passed ozone through it (alone or submerged in solvent/reactant.) On a small scale cooling the gas lower is more convenient also, so using winter temps, salt+ice, or a freezer would allow slightly higher yields from the plasma reactor, and much higher NO2 capacity for the silica gel. At -10C the silica gel may well hold >30% NO2. When prepared by adding excess NO2 to silica gel in DCM at 0C can attain 45% NO2 content AFTER vacuuming off the solvent, and its stable at refrigerator temps for months. I'd try this as my plasma reactor:

I still think the combustion based system is exciting and worth exploring. If you wanted to make kg of NO2, where off grid, or had plentiful (possibly low grade) fuel and expensive electricity, it could be worthwhile. More experimentation required for sure. Personally, instead of using pebble bed heat exchangers to quench the >2000C flue gas, I'd try injecting water directly into a conventional high turbulence venturi burner. This is a known way to rapidly quench hot gasses, and may even improve the yield, while greatly simplifying everything. The NO in the flue gas reacts with O2 quite slowly at these concentrations, so only a <.5% of it is lost to the cooling water. Then dry the gas, run it over a small bed of NO2/silica gel to rapidly catalyze the reaction with O2, and then capture it in the main silica gel bed. Running batchwise would eliminate most of the complex automation in the patent. If you pre gasified your fuel in a crude updraft gasifier, any thing from waste plastic/paper to wood/coal could be used. Normally the vast tar production of updraft gasifiers makes them unusable, but if you directly burn the output before cooling that issue disappears.

In a cold climate you could easily be making >1 ton NO2/year while providing your household heat (and power?) for an extra 15-30% fuel consumption and 50-250kg silica gel. The colder it gets, the faster you produce NO2, but the colder you can cool the gas, and the more the silica gel will hold. Freezing brine tanks to "stock up" on cold during cold weather could allow the silica gel to be used at greater capacity for longer.

I'll gladly consult anyone looking to build one.

[Edited on 5-8-2012 by 497]

A word to the wise: NEUROFEEDBACK

"To expose a 15 Trillion dollar ripoff of the American people by the stockholders of the 1000 largest corporations over the last 100 years will be a tall order of business."
Buckminster Fuller

"No problem can be solved from the same level of consciousness that created it."
Albert Einstein

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