Methanol production - high octane additive for gasoline
Brief information about methanol. Methanol, methyl alcohol, wood alcohol, carbinol, CH 3 OH - the simplest aliphatic alcohol, a colorless liquid with a faint odor, reminiscent of the smell of ethyl alcohol. The boiling point is + 64.5 ° C, the freezing point is 97.8 ° C, the density is 792 g / l. The limits of explosive concentrations in air are 6.7–36% by volume. The octane number is more than 110. The ignition temperature is 467 ° C, the heat of combustion of 24,000 kJ / kg is lower than that of gasoline (44000 kJ / kg), so the consumption of methanol (in liters) will be about two times higher. As a fuel used in racing cars, for example in the "Formula 1".
METHYL ALCOHOL is mixed in any concentration with water, organic solvents and poison, 30 milliliters of methanol drunk can be LETHAL if you do not take urgent measures! Couples are also poisonous!
Traditionally, methanol was obtained by sublimation of wood. But a more promising method for producing methanol is from natural gas. In the future, as this technology is improved, other sources of raw materials, such as biomass (manure), are also possible. Industrial methods for the production of methyl alcohol are not yet sufficiently effective for using methanol as fuel, but in the coming decades the price of oil will only rise and the situation may change in favor of alcohol fuel (especially when using vehicles on fuel cells). Natural gas, as is known, almost 100% consists of methane - CH 4 . In no case should it be confused with bottled gas propane-butane, the latter is a product of oil cracking and is used directly as automobile fuel. However, this is done by many motorists, installing the appropriate equipment. And when using methanol no additional equipment is required. We will describe in detail how, using methanol as a fuel, how to significantly increase engine power. In the meantime, just say that this is achieved by increasing the diameter of the main nozzles or reducing the amount of air in the fuel mixture.
So, about the chemistry of the process of obtaining methanol from natural gas.
In the case of incomplete oxidation, methane is converted to carbon monoxide and hydrogen, and the reaction is as follows:
2СН 4 + О 2 -> 2СО + 4Н 2 +16,1 kcal.
A simpler technologically process is carried out by the reaction of methane conversion with water vapor:
CH 4 + H 2 0—> CO + 3H 2 - 49kcal.
In the first equation is +16.1 kcal. This means that the reaction goes with the release of heat. In the second - with absorption. Nevertheless, we will focus on the second method of producing carbon monoxide and hydrogen. With the presence of these two components, it is already possible to directly synthesize methanol. The reaction is as follows:
CO + 2H 2 <=> CH 3 OH.
The difficulty is that the final product is obtained only at high pressure and high temperature (P> 20 atm., T = 350 degrees), but in the presence of a catalyst, this process shifts to the right and at low pressure. The resulting methanol is removed from the reaction by cooling to condensation, and the non-condensed gases will be burned. With proper combustion of hydrogen and CO residues, no harmful substances are released (CO 2 and H 2 0 waste are harmless), so no exhaust devices are required. Then methanol is poured through the tube, always with a seal (!), Into the canister. As you can see, the chemical process is very simple, it is based on two reactions. Difficulties are only technological and security measures. We are dealing here with highly flammable and toxic substances. We must fear both the explosion and the leakage of these gases. Therefore - it is necessary to strictly observe the technology and the rules of treatment, which we will describe. To assemble the installation, you will need to purchase: a stainless steel sheet (1mm), a seamless stainless steel tube, an outer diameter of 6-8 mm, a wall thickness of at least 1 mm and a length of about 2 meters, a compressor from any domestic refrigerator (available from dumps, but working). Well, needless to say, argon electric welding will be needed.
Heat exchangers are usually composed of tubes surrounded by a cooling medium. In everyday life they are called "coils". For liquids whose thermal conductivity is high, such a heat exchanger may be acceptable. But with the gas situation is completely different. The fact is that at low speeds the gas flow moves laminar and practically does not exchange heat with the environment. Look at the smoke rising from the burning cigarette. This slender wisp of smoke is the laminar flow. The very fact. that the smoke rises, speaks of its high temperature. And the fact that it remains a solid bar at about a height of up to 20 centimeters of lifting indicates that it retains heat. That is, at this distance, even at very low speeds, the gas flow does not have time to cool down and exchange heat with air. It is because of the laminar flow that gas heat exchangers have to be bulky. Inside their tubes appear "drafts", which even dozens of meters practically do not give heat exchange. It is well known to those who have ever driven moonshine. (Any experience is useful!) A long, intensively cooled tube, condensate flows out of it, but it also produces steam. This means that heat transfer is not efficient enough. The problem, however, has solutions and it can be simple. Fill the tube with, for example, copper powder (see fig. 1). For a capacity of 10 l / h, the heat exchanger can be 600 mm long, and for 3 l / h 200 mm should be enough, height h - 20 mm. Particle sizes can vary, the optimum is somewhere in the range of 0.5-1 mm. Considering the tasks of heat exchange, the body material can be both iron, and copper, and aluminum, the packing material — copper, aluminum — can be found.
Then a gas stream will form turbulence around each metal particle. Thus, drafts are immediately eliminated and the flow becomes turbulent. Well and at the same time the contact of gas with the cooled surface is greatly increased. Copper powder packed into the tube constantly receives or transfers heat to the walls, and since the heat conductivity of copper is about 100 thousand times higher than the thermal conductivity of gas, the gas will relatively quickly take on the temperature of the walls if we intensively cool them. It should be borne in mind that with decreasing particle size and increasing their number, the resistance to gas flow also increases. Therefore, it is hardly possible to use particles smaller than 0.5-1 mm for the heat exchanger. Flowing cooling water, of course, it is advisable to skip towards the gas flow. This makes it possible at each point of the heat exchanger to have its own specific temperature. Since the thermal contact is close to ideal, the temperature at the outlet of the condensed liquid will be equal to the temperature of the coolant. This is what the heat exchanger discussed here is. The given sketch is nothing else than a distiller, it’s a moonshine still, it’s a heat exchanger. The performance of such a distiller is approximately 10 liters per hour.
It can also be used for almost any purpose, including a plant for the production of ordinary ethyl alcohol (see Priority No. 1'91 and No. 1-2'92). Such heat exchangers with a huge capacity are hundreds of times smaller than existing ones.
CATALYTIC PUMP (REACTOR, see figure 2)
In existing chemical gas processes, the usual catalyst goes in granules of quite significant size from 10 to 30 mm. The area of contact of gas with such balls is thousands of times smaller than if we used particles of 1–1000 microns. But then the gas is very difficult to pass. In addition, the smallest particles of catalyst rather soon fail due to surface contamination. We have found a way to increase the contact area of the gas with the catalyst, without complicating its permeability in the reactor, and at the same time continuously clean up the so-called "poisoning" of the catalyst itself. This is done as follows. Powder catalyst is mixed with ferromagnetic particles - iron or ferrite powder, which can be obtained by breaking magnets from faulty loudspeakers (note - ferrites lose their magnetic properties at temperatures above 150 degrees C), and ferrites are very solid matter - this is their useful property useful in the future (read below - so as not to specifically add abrasive powder). A mixture of ferromagnetic powder with a catalyst is placed in a non-magnetic tube, for example, from glass, ceramics, or in aluminum or copper. Now look what can be the scheme. Outside the tube are winding coils. Each of them is connected via diodes, for example, as given in Fig.3.
When AC is turned on, the windings are switched alternately with a frequency of 50 Hz. While the ferromagnetic powder continuously compresses and expands the catalyst, providing a pulsating gas permeability. If electromagnets are included in a three-phase network (see Fig. 4), then in this case translational pulsation of compression is ensured, and as a result, the gas will be continuously compressed in the longitudinal direction forward. Thus, the system works like a pump. At the same time - repeatedly mixing the gas, compressing and expanding it and a thousand-fold increasing the intensity of the process on the catalyst. Along the way, catalyst particles rub against each other and about ferrite abrasive powder, which leads to their purification from contaminating films.
The circuit works as follows:
with a frequency of 50 Hz there is a change in polarity in the power supply. The current alternately passes through the winding of 1.3 and 2.4 (see Fig. 2). In this case, a magnetic field appears in them, which magnetizes ferromagnetic particles and causes them to interact with each other, involving catalyst particles in motion. In this way, a gas flow through the small particles alternately arises, followed by a large resistance exerted by the compressed mass of particles. And most importantly: the activity of the catalyst, compressing and decompressing the reacting gas, for reasons not yet studied, increases an additional 20-50 times. The work of the described catalytic reactor is equivalent to a reactor measuring 20–30 meters. The reactor capacity can be increased, including windings in a three-phase network. In this case, the system does not work as valves, but as an active pump, combining all the positive effects of the first circuit and additionally forcing the gas to move in the direction of the phase shift offset. With this inclusion it is important to choose the right phasing. So, in the reactor shown here, the following positive factors work:
1. The increase in the area of the catalyst in 300-1000 times due to the reduction of particle size.
2. There is a continuous cleaning of the catalyst from surface contamination.
3. Constant pressure pulsations of the reacting gases between the catalyst particles, and in the second scheme, gas transfer inside the reactor itself also takes place.
The disadvantage of this reactor - increased resistance to gas flow - is eliminated by alternating compaction - the release of particles inside even-odd coils. One important detail: it is necessary to insulate the coils from the reactor vessel. In this regard, as well as for practical reasons, the author of the site made the following changes (see fig. Right):
From a blank (bronze or brass) with a diameter of 50 mm, we carve the reactor vessel. Dimensions can be taken as before - 160 mm total length, working reactor length about 140 mm, internal. diameter 33 mm, wall thickness approximately 5 ... 8 mm, i.e. The outer diameter of about 50 mm of the same diameter is a plug, their thickness is 20 mm and each has a M36x1.0mm thread and a length of 10mm. All this should be made of the same material! Adapters or simply connecting seamless steel tubes with an inner diameter of 6 ... 8 mm and a wall thickness of about 2 mm are inserted and welded to the plugs in the holes. This construction must be insulated from the outside with sheet asbestos and divided along its entire length into four sections using five partitions, also cut from sheet asbestos. To fix the partitions, you can smear them with silicate glue, after drying, copper wire (d = 0.15mm) is applied to each section. The resistance, measured by an ohmmeter, for each section should be about 1200_Ω. The windings are turned on according to the scheme of Fig. 3 through a voltage regulator (for example: laboratory transformer - LATR), to avoid overheating of the windings, they must be cooled, for this you can lay glass tubes with a diameter of 6 ... 8 mm under the windings, with forced blowing coils, controlled temperatures inside the reactor.
It should be noted that a similar reactor design (Fig. 2) was claimed for a patent (by G.N. Vaks), it can work in any catalytic gas processes. Therefore, for chemists, this is not a domestic development, but a fundamentally new, not yet fully studied, but effective reactor. Apparently, the effects will increase when applying rectangular pulses or high frequency oscillations.
PRODUCTION SYNTHESIS — GAS.SYNTHESIS — GASOM is a mixture of H 2 and CO, which is necessary for the production of methanol. Therefore, first consider the technology of synthesis gas. The traditional methods for producing CO and H 2 from methane (CH 4 ) are that methane is mixed with water vapor and in a heated state enters the reactor, where a metered amount of oxygen is added to the vapor-methane mixture. When this happens the following reactions:
 CH 4 + 20 2 <-> CO 2 + 2H 2 O + 890 kJ;
 CH 4 + H 2 0 <-> CO + 3N 2 - 206 kJ;
 CH 4 + CO 2 <-> 2CO + 3N 2 - 248 kJ;
 2H 2 + 0 2 <-> 2H 2 O + 484 kj;
 СО 2 + Н 2 <-> СО + Н 2 0 - 41.2 kJ.
As you can see, some endothermic reactions - with the absorption of heat - and some exothermic - with the release. Our task is to create such a balance that the reactions go with controlled heat release. So, at first, a metered mixture of H 2 O and CH 4 is required. Traditional methods of conducting this process are complicated and cumbersome. We will saturate the methane with water vapor by passing bubbles of this gas through water heated to 100 degrees Celsius, and in order for the bubbles to actively break, we place solid ferrite particles 1–2 mm in size on their way. But in this mass, sooner or later, the bubbles find their way and then, practically without breaking, pass through the formed channel. To prevent this from happening, we put the particles from the ferrite and the mixing chamber into a solenoid with the supply of alternating current. This is a significant difference between our dispersant (see Figure 5). Under the action of vibration of ferrite particles in a pulsating magnetic field, methane bubbles constantly break down, go through a complicated zigzag path and are saturated with water vapor. There are no strict requirements to the solenoid, since it is powered from the LATR or from the dimmer (commercially available). Adjusting the voltage on the solenoid is necessary so that by changing the magnetic field, at the same time changing the degree of saturation of methane with water vapor. The purpose of these changes will be discussed below. The number of turns in the coil can be from 500 to 1000. The wire diameter is 0.1— 0.3 mm. The dispersant tube is taken from a non-ferromagnetic metal, so it will heat up in an alternating magnetic field. In addition, methane and enters the water heated. Therefore, a special water heater is not required (approx. Erroneous opinion! Water must first be heated to boiling, for example, with a gas heater, otherwise you will not get the right amount of water vapor). A tank is also needed to feed water, since it is continuously consumed to form a vapor-methane mixture, for this purpose a drain tank from a standard toilet bowl is suitable, whose drain hole is covered with a steel plate, with a welded drain tube, the end of this tube is inserted into the disperser and bent downward on 180 ° (see figure 5), this is done with a view to safety, to prevent methane gas from entering the tank.
ATTENTION: it is necessary to arrange the tank in such a way that the water level in the mixer-disperser does not rise above 150 mm, i.e. up to half of its height, this is due to the pressure in the gas network (= 150 mm of water column!), otherwise the water will prevent the passage of methane gas into the dispersant. Also, the water before being fed into the tank must be cleaned of chlorine impurities. This will cope with the standard water purification products for domestic purposes.
The finished steam-methane mixture is heated to a temperature of 550–600 degrees in a HEAT EXCHANGER. The device of the heat exchanger (Fig. 6) has already been described in some detail above (see Fig. 1). Therefore, we present only the specification of sizes. The heat exchanger is made of stainless steel, be sure to boil in inert gas. Stainless steel tubes are attached to the body only by welding. The heat exchanger filler is made from 1-2 millimeter particles of ceramics. This may be, for example, crushed china. It is necessary to fill the container tightly enough, with obligatory shaking. Possible error: if the heat exchanger is insufficiently filled with ceramic particles, the gas will find its way, and the flows will be laminar, which deteriorates the heat exchange.
ATTENTION: THE ENTIRE SYSTEM MUST BE SEALED. No leaks! In the heat exchanger 3.2 (see figure 10) the temperatures are high! No seals are used - only argon welding.
THE MOST DIFFICULT AND RESPONSIBLE KIT OF THE INSTALLATION IS A CONVERTER-REACTOR (see Fig. 7), where methane conversion occurs (it turns into synthesis gas). The converter consists of an oxygen-vapor-methane mixer and reaction catalytic columns. In general, the reaction goes with the release of heat. However, in our case, in order for the process to start, we carry out heating on the supply pipes, since we carry out the methane conversion by the reaction :
CH 4 + H 2 O <-> CO + ZN 2 - 206 kJ,
with the loss of heat, which means it is necessary to bring heat to the converter. To do this, we pass the steam-methane gas through tubes heated by burners. The converter works as follows:
The vapor-methane mixture enters the chamber in which stainless steel tubes are welded. The number of tubes can be from 5 to 20, depending on the desired performance of the converter. The space of the upper chamber must be necessarily tightly packed with coarse sand or crushed ceramics or stainless steel shreds, particle size 0.5-1.5 mm. This is necessary for better mixing of gases, and most importantly - for the flame-ignition. When combining air with hot methane, a fire may occur. Therefore, in the upper chamber, stuffing is carried out with the obligatory shaking and filling. The tubes and the collecting chamber (in Fig. 7) are packed with particles containing a catalyst, nickel oxide.
The mass fraction of nickel in the catalyst in terms of NiO should be at least 7.5 ± 1.5%. The residual methane content in the conversion with steam of natural gas (steam: gas ratio = 2: 1), at a temperature of 500 ° - 38.5%, and at 800 ° - no more than 1.5%. The mass fraction of "harmful" sulfur in terms of SOZ should be no more than 0.005%.
You can make such a catalyst yourself (but it's better to find a ready-made, industrial catalyst). To do this, you need to heat nickel particles in the air. If there is no pure nickel, then it can be made from nickel-containing 10-15-20 kopek coins of the USSR. Erase them on a rough abrasive wheel or small milling cutter. Abrasive in the packing is allowed. Calcify the resulting powder and mix in a ratio of 1/3 of the volume of the powder with 2/3 of the volume of ground ceramic (0.5 mm) or pure coarse sand.
The gap between the upper parts of the tubes is filled to 10 cm with any high-temperature heat insulator. This is done so as not to overheat the upper chamber. There is an easy way to get such a heat insulator. Ordinary office silicate glue is mixed with 10–15 weight percent of fine ground chalk or talc or clay. Stir thoroughly. Pour the mixture in a thin layer and immediately burn it with the fire of a blowtorch. Water boiled in the glue forms a pumice-like white mass. When it cools down, they again pour a layer of glue with chalk on it and again process it with a flame. And so repeat until, until they receive, the required layer of insulator. After the assembly of the converter is completed, it is placed in a steel box, which is necessarily insulated with a material that can withstand temperatures up to 1000 degrees, for example, asbestos. Injection type burners, can be any, from 5 pieces to 8. The greater the number, the more uniform the heating. A system using a single burner is also possible. Its flame has several exits through the holes in the pipe. Gas burners are commercially available, for example, those used to process skis. There are also gas blowtorches for sale, so we give only a general scheme. The burners should be connected in parallel and regulated by a standard gas tap, for example, from a gas stove, but it is better to take an automatic regulator from a household gas stove - expensive, but reliable and convenient - you can use it to set the desired temperature inside the converter-reactor, thereby increasing the degree of autonomy installation in general.
MORE ONE OF THE RESPONSIBLE NODES is an ejector faucet for supplying air and methane to the converter chamber (see figure 8.). The ejector faucet of air and methane consists of two nozzles; one delivers methane saturated with water vapor and the other is an air ejector. The air comes from the compressor, its quantity is regulated by the pressure valve (Fig.9.). The compressor can be from almost any domestic refrigerator, the pressure is regulated from "zero" to the required one, which will not be much higher than the pressure in the gas line (i.e. => 150 mm of water).
The need for supplying air (oxygen) to the converter is due to the fact that the reaction of  requires that some of the hydrogen be absorbed with the release of CO, thereby increasing the amount of carbon monoxide to a proportion of CO: H 2 == 1: 2, i.e. The number of moles (volumes) of hydrogen should be twice as large as volumes of carbon monoxide ( note: the presence of excess air will lead to the synthesis of by-products — acids, higher alcohols — sivukha, and other harmful components). But the occurrence of CO 2 will occur by the reaction of  with the release of a large amount of heat. Therefore, we do not turn on the compressor at the beginning of the process and keep the screw turned out. Air is not supplied. And as the chamber warms up and the entire system is turned on, we will gradually turn on the compressor and screw in the pressure valve screw, increase the air supply and simultaneously reduce the flame on the burners. We will control the amount of excess hydrogen at the outlet of the methanol condenser (heat exchanger 3. and 3.1) through wick (13 cm. figure 10), reducing it. The wick for the afterburning of the excess synthesis gas is an 8 mm tube, 100 mm long, filled with copper wire along the entire length, so that the flame does not go down to the canister with methanol. We dismantled all the units of the methanol production unit. As is clear from the previous one, the entire installation consists of two main components: a converter for creating synthesis gas (methane conversion) and a methanol synthesizer. The synthesizer (catalytic pump, see figure 2) is fairly well described above. The only thing that should be added is the need to install a heat insulator between the pipe and the coil. How to make a heat insulator, we reported when describing the manufacture of the converter (see figure 7).
Let's pass to the GENERAL SCHEME of INSTALLATION. Work of the general scheme: from the gas line, methane enters through the valve (14) into the heat exchanger (3.1), heats up to 250–300 ° C, then enters the filtering reactor (15), which operates according to the principle of a catalytic pump (see Figure 2- only pipe diameter = 8 cm), contains zinc oxide to clean the gas from sulfur impurities, and only then the gas enters the mixer-disperser (2), where it is saturated with water vapor. Water (distilled) is added to the dispersant continuously from the tank (1). The released gas mixture enters the heat exchanger (3.2), where it is heated to 500–600 ° C and goes to the converter (4). On NiO - catalyst at a temperature of 800 ° C, the reaction occurs . The burners (12) operate to create this temperature. After the temperature regimes are established, the compressor (5) is turned on and air is gradually supplied to the mixer (11). The pressure is increased by turning the screw in the valve (8). At the same time, we reduce the flame on the burners (12) using the valve (14.2). The synthesis gas obtained at the outlet enters the heat exchangers (3.1; 3.2), where it is cooled to a temperature of 320–350 °. Then the synthesis — gas enters the methanol synthesizer (6), where on the catalyst from a mixture of the same amount of ZnO, CuO, CoO it is converted to methanol CH 3 OH. The mixture of gaseous products at the outlet is cooled in a heat exchanger (3.3). which is described above (see figure 1) and enters the cumulative tank (10). In its upper part there is a tube - a wick (13), where products that did not react in the process are burned. Burning is a must, a must!
SEVERAL TIPS. Catalysts can be prepared by calcining powdered metals in air. Temperature measurement can be performed using thermal indicator paints, which are currently quite common. Measurement should be carried out on the input and output tubes. If you do not get thermal paints, you can make an alloy of tin - lead - zinc. With certain experimentally determined mixing proportions, they will have the necessary melting point. By applying the obtained alloys to the tubes and observing their melting, it is possible to control the temperature with some error. If you have not allowed the formation of gas pockets (i.e., all the cavities are completely filled with the corresponding crumb), if you have eliminated leaks and most importantly, the wick (11) is lit on time and constantly burning, then the installation will be absolutely safe. By selecting catalysts it is possible to increase thermal efficiency, to increase the percentage of methanol output. To achieve the optimum, experiments are required here. They are held in many institutions in different countries. In Russia, such institutes include, for example, the GIAP (State Institute of Nitrogen Industry). It should be borne in mind that the production of methanol from natural gas in compact installations is a new matter, and many processes are still not well understood. At the same time, methanol is one of the most environmentally friendly and almost perfect fuels. And, most importantly, getting it is based on unlimited and renewable resources - methane.