US20080178784A1

US20080178784A1 - Simultaneous Production of Electricity and Liquid Fuels from Municipal Solid Wastes

Info

Publication number: US20080178784A1
Application number: US12/020,785
Authority: US
Inventors: William A. Farone
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-01-29
Filing date: 2008-01-28
Publication date: 2008-07-31

Abstract

An energy self sufficient process for treatment of municipal solid waste includes the production of mixed alcohols. The process also includes gasification of the solid waste producing a gas that can provide either or both electricity and heat to further power the process.

Description

This application claims the benefit of U.S. Provisional Application No. 60/886,986, filed Jan. 29, 2007.

FIELD OF THE INVENTION

The present invention relates to a new and novel process for the treatment of municipal solid wastes (MSW). It pertains to a process wherein the materials in MSW (other than those inorganic materials normally classed as ash) are converted to synthesis gas which is used simultaneously in two ways. Portions of the synthesis gas are utilized to power (1) either a turbine, a boiler or both which provide heat, electricity, or (2) both a turbine and a boiler to run the remainder of the process. Another portion of the synthesis gas is catalytically reacted to form mixed alcohols which are condensed. The mixed alcohols present in the liquid are separated from other combustible liquids that may be present. Any remaining waste liquids are sent back to the process front end for gasification. Any synthesis gas that does not react to form products is sent to the boiler. There are no waste products from the mixed alcohol reaction.

Municipal Solid Wastes

Many communities, businesses, and individuals are looking at more creative ways to reduce and manage Municipal Solid Waste (MSW) which is more commonly known as trash or garbage. Present management techniques can include a coordinated mix of practices that includes source reduction, recycling (including composting), and disposal. The most environmentally sound management of MSW is achieved when these approaches are implemented according to EPA's preferred order: source reduction first, recycling and composting second, and disposal in landfills or waste combustors last. Landfills receive primarily household waste but can also receive non-hazardous sludge, industrial solid waste and construction and demolition debris. These landfills must be designed to protect the environment from the contaminants which may be present in the solid waste stream. The preferred method of waste management is source reduction of waste. However according to EPA, over the past 35 years the amount of waste each person creates has almost doubled from 2.7 to 4.4 pounds per day. In 2005, 245.7 million tons of municipal solid waste or MSW were generated in the United States. Organic materials comprising yard trimmings, food scraps, wood waste, and paper and paperboard products are the largest components of MSW and make up more than two-thirds of the solid waste stream.

Definitions

The words “comprising,” “having,” “containing,” and “including,” and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items.
The term “municipal solid waste” refers to that material more commonly known as trash or garbage and is collected from households and businesses. It does not contain what is classified by governmental standards as hazardous waste.
The term “syngas” (synthesis gas) refers to the synthesis gas generated/produced during the gasification of a carbon containing fuel to a gaseous product and which contains carbon monoxide (CO) and hydrogen (H₂) among other gases.
The term “low pressure” is defined as about or below 5 atm.
The term “critical temperature” is the temperature above which it is not possible to distinguish between the liquid and the gas phases. The substance is referred to as a supercritical fluid.
The term “critical pressure” is the pressure above which it is not possible to distinguish between the liquid and gas phases. The substance is referred to as a supercritical fluid.
The following common abbreviations and symbols are used:
T_cCritical temperature
P_cCritical pressure
MSW Municipal Solid Waste
psi pressure per square inch
psia pressure per square inch absolute
CO carbon monoxide
H₂hydrogen
CO₂carbon dioxide
CH₃OH methanol; methyl alcohol
CH₄methane
C₂H₂acetylene
C₂H₄ethylene
C₂H₄O acetaldehyde
C₂H₆ethane
C₂H₆O ethanol; ethyl alcohol
Mo molybdenum
MoS₂molybdenum disulfide
K₂CO₃potassium carbonate
CoS cobalt sulfide
TCD thermal conductivity
FID flame ionization detector
All publications, including patents, published patent applications, scientific or trade publications and the like, cited in this specification are hereby incorporated herein in their entirety.

BRIEF DESCRIPTION OF DRAWING

FIG. 1. Gasification of MSW to chemical products. FIG. 1 is a schematic diagram of the process as described. This diagram illustrates the steps of the process wherein MSW is converted to energy and alcohols.

FIG. 2. P_cvs. Composition for Methanol-Water

FIG. 1 is diagrammatic and is not drawn to scale. Corresponding parts generally bear the same reference numerals.

SUMMARY

The process as illustrated in the FIG. 1 and as described below converts MSW into liquid fuel and electricity with minimal and acceptable environmental waste. Residual wastes such as glass, sand and inorganic solids are separated out of the first stage (Front End Processing 1) and the normal boiler or turbine output gases meet all environmental standards. Any ash from the gasification system 2 could be combined with similar material from the first stage processing 1. The oxidizable matter that is present in the MSW (except for the non-oxidizable ash) is converted to useful liquid fuel or solvent products either for use in the process if not salable or primarily for other consumers.

Gasification of Municipal Solid Waste

The MSW arrives at a facility and is processed in the normal and usual fashion 1 wherein selected materials are removed from the MSW. The removed contents are materials selected from the group consisting of stones, sand, metals, and glass. The “processed” or “cleaned” MSW is then transported to a gasification system 2. This system may be a fluid bed gasifier, examples of which are described by Energy Products of Idaho (EPI) in U.S. Pat. Nos. 5,060,584 and 5,101,742. There are other gasification systems commercially available from various suppliers which are non-fluidized beds
The synthesis gas (syngas) produced within the gasification system 2 contains carbon monoxide (CO) and hydrogen (H₂). The gasification system 2 is a partial oxidation/pyrolysis step to make the syngas and is not a combustion system. Combustion systems produce heat by converting the substances to carbon dioxide and water. Frequently a small excess of oxygen is used to ensure completeness of the combustion reaction. In gasification the substances are oxidized to carbon monoxide and hydrogen. In one aspect the gas has more hydrogen at about 2:1 mole (volume) ratio. Residual solids are removed as ash. This ash is recombined with the non-oxidizable material from the front end processing 1 for use as aggregate or environmentally acceptable land fill. These materials cannot be gasified further. The syngas flows to either a boiler, a turbine, or both 3. In one implementation the temperature of the syngas is about or greater than 700° C. and is at low pressure. In another implementation the temperature is about 925° C.

Production of Electricity and Steam

The boiler/turbine step 3 produces electricity which may be used to run the MSW facility or may be provided to or sold to other users. The steam produced is then sent back to the front end of the process 1 or used in the distillation 7 of the mixed alcohols. Some steam is normally used to help classify the MSW in the separation step 1. This process step enables one to eliminate the need for obtaining electricity, power, or steam from external sources.
In one implementation a portion of the syngas is sent to a heat exchange unit 4 wherein the syngas is cooled by an air stream and the now hot air is resent to the front end of the process 1 or is used in the mixed alcohol system (catalytic reactor 6). Excess hot gas or steam can also be utilized to run a distillation separation process 7 for the mixed alcohols produced in the catalytic reactor 6. Another portion of the syngas is sent to a gas compression and conditioning system 5 wherein the syngas is cooled and compressed. In one implementation the syngas is cooled to about 260° C. and compressed to about 1500 psi.
The syngas from the gas compression and conditioning step 5 is sent to a catalytic reactor 6 wherein the mixed alcohol production occurs. The pressure in the catalytic reactor 6 is maintained above the critical pressure of the mixture of the reactants in the system 6 including alcohols and water for at least some period during the reaction and preferably for the entire reaction time. During the period when either the pressure is above Pc or the temperature is above Tc, the mixture is supercritical as it is neither a gas nor a liquid. (Wylen and Sonntag; Fundamentals of Classical Thermodynamics, 1973). Substances in a solution cannot be independently supercritical. Normally when a substance is below the critical temperature it is referred to as a compressed gas or liquid and at temperatures above the critical temperature as a superheated vapor or supercritical fluid.

Mixed Alcohols

In discussing mixed alcohols production processes, other individuals in the field refer to the catalytic systems 6 for mixed alcohols production as ‘liquid’ systems. However, liquids do not exist at the stated temperature and pressure as described in some of the processes. This has caused confusion in the previous literature as the variations and improvements ascribed to the catalysts are mainly caused by the substance not being in a supercritical state under the desired conditions.
Mixed alcohols have been produced via catalytic reactors (SIR H243, U.S. Pat. No. 4,831,060 (Stevens '060), U.S. Pat. No. 4,762,858 (Hucul '858), U.S. Pat. No. 4,752,623, U.S. Pat. No. 6,753,353) by others. These processes use a wide range of conditions and some of the conditions were primarily selected to control the number of moles of the reactants. The pressure range given in some of these processes are from 25 to 3000 psi with temperatures from 200° C. to 350° C. Stevens '060 states that pressures up 10,000 psi can be used.
Nanocatalysts have also been used but the nanocatalysts use the same temperatures, pressures, and catalyst materials as the earlier catalytic methodology. These nanocatalysts present additional problems since they are hazardous materials capable of being inhaled, they are more difficult to produce, and there are costly issues of filtering them from the system.
Others use conditions that meet the criteria of supercritical pressure or supercritical temperature during part of the reaction of the syngas, however these conditions are not maintained through out the process. The present findings discovered that the supercritical pressure or supercritical temperature should be maintained throughout the reaction time. By keeping the pressure just above the P_cfor the particular mixture in the reactor 6 there is a concurrent savings in energy by not using excessive pressure.
Previous processes found the conversion of syngas to mixed alcohols to be about 20-30% per pass of the syngas through the reactor. The use of re-circulated gas is not as efficient as there is less CO and hydrogen present.

Reduction of Gases to Alcohols

The gases at about 925° C. and 1-2 atm are cooled quickly to about 260° C. while being compressed up to about 100 to 110 atm in the gas compression stage (Gas compression, conditioning 5). Under these conditions most of the chemicals in the gas and especially the desired products are in the supercritical state, that is, the chemicals are neither liquid nor gas but rather a fluid of uniform intermolecular dimensions. This condition allows the catalysts in the catalytic reactor 6 to selectively remove the desired compounds on the surface of the catalyst thus both promoting the reactions one desires and suppressing the ones that are not desired. The catalyst selection depends on the chemicals that are desired to be produced.
For example, as will be seen further below, the natural thermodynamic state of affairs favors the formation of hydrocarbons under the conditions as illustrated throughout the range of gases from 1:1 H₂:CO₂(as in cellulose gasification) up to 2:1 H₂:CO as in mixed waste MSW decomposition. By selectively removing alcohols by surface interaction with the catalyst one shifts the equilibrium to favor these compounds very dramatically. This is a direct implementation of LeChatelier's Principle for driving reactions especially under conditions that are not favorable. For example in the reaction of
A+B
C+D.
One drives the reaction to the right by removing either or both of C and D as they are formed and providing excess A and/or B.
For the catalysts to operate with the higher degree of selectivity required to shift the products to the desired end products, supercritical conditions provide increased reactions kinetics and appear to be necessary. Therefore to make methanol (Tc=239° C., Pc=79.9 atm), ethanol (Tc=243° C., Pc=62.96 atm), n-propyl alcohol (Tc=263.6° C., Pc=51.0 atm), iso-propyl alcohol (Tc=235.16° C., Pc=47.0 atm) in high yield while limiting the water in the product stream, it is necessary to stay above the critical pressure or temperature.
A fluid can be kept in the supercritical state by exceeding either the supercritical temperature or supercritical pressure. Exceeding the supercritical pressure is useful because the average distance between molecules is reduced. Reactions in a vessel are easier to maintain with the desired conditions by controlling the pressure under isothermal temperature conditions.
In the complex systems of this instant invention the supercritical temperature and supercritical pressure are of the entire mixture since the entire fluid mixture is either supercritical or not. An explanation of the nature of the supercritical state is given in “Fundamentals of Classical Thermodynamics” by Gordon J. Van Wylen and Richard E. Sonntag, John Wiley and Sons. Inc., Second Edition, 1973, pp. 42-43. The means of determining the supercritical properties of mixtures is explained by Robert C. Reid, John M. Prausnitz and Bruce E. Poling in “The Properties of Gases & Liquids”, Fourth Edition, Mc-Graw-Hill, 1987 Chapter 5, pp. 121-135.
A catalyst that operates by removing the products that are formed from the reaction interface through use of the energy or spacing of molecules in a supercritical state is affected by the state of the entire system. In the fixed volume reactor the supercritical state is maintained by controlling pressure and temperature and then allowing kinetics (the rate at which the reactions proceed) and the removal of the products by adsorption on the catalyst to define the composition of the mixture.
A thermodynamic analysis is useful as a first step because the analysis indicates the distribution of products from a mixture of chemicals at a specific temperature, pressure, and volume in the absence of removing the products as the products are formed. Table 1 is an example of the potential equilibrium distribution of the noted gases when the ratios of the input feed materials have a ratio of C:H:O of 1:2:1. This table is calculated using standard thermodynamic functions for the noted products at the condition of equilibrium using the standard Free Energy Minimization technique. An example of the use of this technique can be found in Perry's Chemical Engineers' Handbook published by McGraw Hill. In the 1999 CD ROM version it is on pages 4-33-4-34.
Table 1 is a summary of such a calculation at 1250° K. (977° C.) and 1 atm pressure. The calculations must be performed for an assumed distribution of products. From experimental data it is known that the materials listed in Table 1 are usually found in such gases.

TABLE 1

Calculated Equilibrium for C:H:O 1:2:1 at 1250° K and 1 atm

	mol fraction	mol fraction	mass fraction
Species	in the phase	in the mixture	in mixture	Mols

(fluid phase)
CH₃OH	1.082E−09	1.075E−09	2.295E−09	2.150E−09
CO	4.945E−01	4.915E−01	9.170E−01	9.830E−01
CO₂	2.391E−03	2.377E−03	6.967E−03	4.754E−03
H₂	4.993E−01	4.963E−01	6.664E−02	9.925E−01
H₂O	3.759E−03	3.736E−03	4.483E−03	7.472E−03
O₂	6.651E−20	6.610E−20	1.409E−19	1.322E−19
(condensed
Phase)
C (Solid)	1.000E+00	6.113E−03	4.890E−03	1.223E−02

From the column (Table 1) of mass fractions in the mixture it is evident that the mixture is predominantly CO and H₂with some water and CO₂. There is some solid carbon but the fraction is small compared to CO and H₂. If the mixture is compressed quickly after filtering the solid Carbon, a state at 530° K. (257° C.) and 140 atm is achieved as shown in Table 2.

TABLE 2

Predicted Equilibrium for Table 1 Gas Phase at 530° K and 140 atm.

	mol fraction	mol	mass fraction		mass fraction
species	in the phase	fraction in mixture	in mixture	Mols	with catalyst

CH₃OH	2.468E−09	2.468E−09	4.390E−09	2.468E−09	3.553E−01
CO	1.533E−04	1.533E−04	2.384E−04	1.533E−04	1.537E−04
CO₂	0.000E+00	0.000E+00	0.000E+00	0.000E+00	0.000E+00
H₂	1.533E−04	1.533E−04	1.716E−05	1.533E−04	1.106E−05
H₂O	9.997E−01	9.997E−01	9.997E−01	9.998E−01	6.445E−01
O₂	3.928E−38	3.928E−38	6.977E−38	3.929E−38	4.498E−38

Thermodynamics predicts that there would be very little methanol (CH₃OH) in the mixture with most of the mass being converted to water. Although the mixture may have started out in the supercritical state as the mixture is cooled down with an increase in pressure, the mixture passes out of that state. The mixture's supercritical conditions are controlled by the massive amount of water that has Tc=374.2° C., Pc=218.3 atm.
The far right hand column (mass fraction with catalyst) of Table 2 indicates what happens if methanol is continually removed from the system via the catalysts such as described by Stevens '060, Hucul '858 or others while maintaining the same equilibrium ratios of the other products. From the state with the equilibrium thermodynamics being used a single time, when the methanol is removed continually via the catalyst the equilibrium thermodynamics is used repeatedly. The reaction is driven kinetically to form more methanol. The final values in the right hand column are typical of those actually seen with various catalysts. The calculated thermodynamics and kinetics in Table 2 indicate that 35% of the mixture could be methanol. Under these conditions a large quantity of water is produced but the catalyst delays the onset of the mixture leaving the supercritical state as the catalyst delays the water reaction and allows the methanol reaction to proceed.
The final solution is approximately ⅔ water and ⅓ methanol. In this case the critical pressure of methanol and water mixtures are shown in FIG. 2. It can be seen that when the mole fraction of methanol in the mixture is above about 0.20, the critical pressure will be below 2000 psia (136 atm.). The ratio of water to methanol in Table 2 is such that the methanol mole fraction is about 0.23. The calculation is done in Table 2 for 140 atm. The mixture never passes out of the supercritical state. In cases where the mixture starts in the supercritical state and passes out of such a state it is possible to make alcohols but the operating conditions objective in this instant invention is to keep the supercritical fluid in the supercritical state for the longest time possible during the actual reaction.
These calculations are given to aid in the explanation of how the system works and may not exactly define the actual values as the number of products that can be produced is large. If the species around ethanol are included in the calculation and some of the other possible hydrocarbons are added, then the results are as given in Table 3.

TABLE 3

Calculated Equilibrium at 530° K and 100 atm.

	mol fraction in	mol fraction in	mass fraction		mass fraction
species	the phase	mixture	in mixture	Mols	with catalysts

CH₃OH	6.356E−09	6.356E−09	3.710E−09	9.541E−09	3.099E−01
CH₄	4.993E−01	4.993E−01	3.752E−01	7.494E−01	1.531E−01
CO	8.948E−06	8.948E−06	1.174E−05	1.343E−05	4.792E−06
CO₂	1.669E−01	1.669E−01	3.441E−01	2.505E−01	1.404E−01
C₂H₂	5.650E−22	5.650E−22	6.891E−22	8.480E−22	2.812E−22
C₂H₄	1.099E−11	1.099E−11	1.444E−11	1.649E−11	5.892E−12
C₂H₄O	8.359E−12	8.359E−12	1.725E−11	1.255E−11	7.040E−12
C₂H₆	1.865E−05	1.865E−05	2.626E−05	2.799E−05	1.072E−05
C₂H₆O	3.735E−12	3.735E−12	8.060E−12	5.606E−12	2.820E−01
H₂	1.426E−03	1.426E−03	1.347E−04	2.140E−03	5.495E−05
H₂O	3.324E−01	3.324E−01	2.805E−01	4.990E−01	1.145E−01
O₂	7.030E−41	7.030E−41	1.054E−40	1.055E−40	4.300E−41
Acetic	3.093E−09	3.093E−09	8.701E−09	4.642E−09	3.551E−09
Acid

The amount of methanol produced by the catalytic continuous removal in this case is 31% and the ethanol is 28.2%. The same assumption of catalytic behavior was made as in Table 2 with the additional assumption that the catalyst was 350 times more selective for ethanol than methanol. This is similar to relative ratios seen with catalysts in the Stevens '060 and Hucul '858 patents.
The greater the variety of alcohols produced the easier it is to keep the systems supercritical because the concentration of water is less of the total produced mass. The ability to perform these calculations does not imply that these methods are predictive because each catalyst exhibits different behavior. While the outcomes can not be predicted, the calculations-offer a way of understanding the phenomena involved and thus allow better optimization than has been achieved in other processes to date.
The liquid and gas compositions of the reaction mixture in the catalytic reactor 6 can be monitored. The measured composition of the components can be used to calculate the supercritical pressure of the mixture and the pressure adjusted to maintain a pressure above the supercritical pressure.
An unexpected and novel feature of this instant invention is that the overall process produces no waste materials from the catalytic reaction step 6. Other processes have unreacted gases and unusable liquids that increase cost and present an environmental disposal problem. The unreacted exhaust gases in other processes are sent back through the catalytic reactor lowering the efficiency of the operation. In the instant invention any unreacted gases are sent back to the boiler or turbine 3 to produce electricity and any unusable liquids are still combustible and these liquids are recycled to the gasifier 2.
Another new and novel feature of this instant invention is the purification scheme 7 for the mixed alcohols from synthesis gas with varying levels of contaminating substances. When the mixed alcohols emerge from the reactor, the alcohols are hot, usually in a gaseous state and need cooling to be liquefied. Any substances with higher boiling points will condense first upon leaving the catalytic reactor 6 and then the lower boiling alcohols can be collected. The substances that are found not to be suitable for alcohol fuels can be sent back into the gasifier 2 and the emerging gases that did not convert to mixed alcohols are sent back to the turbine 3. This reutilization of unreacted substances makes an otherwise difficult process of producing alcohols via gas reforming economically possible.
In another aspect if a separate distillation column 7 for the alcohol separation was used after the mixed alcohol production, the “non alcohol fuel” fractions are sent back to the gasifier 2 for reprocessing.
The stream of synthesis gas that is utilized for the mixed alcohol production could be sent to a different process to be used for the production of other chemical entities such as hydrocarbons, ethers, or esters.
Unexpectedly the only waste products from this treatment process of MSW are the glass, sand, metals, and other similar solids out of the first stage 1 and the normal boiler or turbine 3 output gases that meet all present environmental standards. Any ash that comes from the gasification process step 2 is combined with similar material from the first stage (front end processing 1). Surprisingly virtually all of the oxidizable substances except for the non-oxidizable ash in the MSW is converted to useful products.
While the above description contains many particulars, these should not be considered limitations on the scope of the disclosure, but rather a demonstration of embodiments thereof. The process and methods disclosed herein include any combination of the different species or embodiments disclosed. Accordingly, it is not intended that the scope of the disclosure in any way be limited by the above description. The various elements of the claims and claims themselves may be combined in any combination, in accordance with the teachings of the present disclosure, which includes the claims.

Production of Alcohol

The process of mixed alcohol synthesis was carried out by passing a mixture of carbon monoxide and hydrogen over a catalyst. In the presence of the catalyst, the two gases reacted to produce alcohols, with either water or carbon dioxide as a by-product. To be efficient, the catalyst must yield a high weight ratio of product per unit weight of catalyst in a given period of time. An additional requirement is that the catalyst must be stable and active over a long period of time.
Among the various catalysts, Mo-based catalysts are considered to have the highest selectivity for formation of alcohols. MoS₂-based catalysts, first developed by Dow Chemicals, exhibit high resistance to sulfur poisoning. It has been reported that the addition of cobalt to the alkali-promoted MoS₂enhances the selectivity of ethanol. Potassium carbonate has shown to work as a best cation additive for alcohol selectivity. The optimum K₂CO₃loading on MoS₂catalyst has been reported as 17%.
The catalyst was prepared by mixing and grinding the three ingredients, CoS, MoS₂and K₂CO₃, then coating the mixture on alumina pellets. A tablet agent was used to aid the coating process.

EXAMPLE A

Pressure of 500 psi

250 grams of catalyst (64% MoS₂/18.4% CoS/17% K₂CO₃supported on alumina beads) were placed in a one liter stainless steel high pressure reactor. The weight of the active component (MoS₂/CoS/K₂CO₃) of the catalyst was 50 grams. Premixed carbon monoxide and hydrogen gas (CO: H_2;1:1) was passed through the catalyst bed at 500 psi and 260° C., at a flow rate of 5 liters/min. The reaction products were passed through a condenser where alcohols and liquid hydrocarbons could condense. Gaseous hydrocarbons were allowed to exit through a vent into a fume hood. These materials could be combusted in a modified burner. Gas samples were obtained from a sample port on the exit side of the condenser and analyzed via gas chromatography (GC).

EXAMPLE B

Pressure of 500 psi

540 grams of catalyst (64% MoS₂/18.4% CoS/17% K₂CO₃supported on crushed alumina beads) were placed in a one liter stainless steel high pressure reactor. The weight of the active component (MoS₂/CoS/K₂CO₃) of the catalyst was 100 grams. The premixed carbon monoxide and hydrogen gas (CO:H_2;2:1) was passed through the catalyst bed at 500 psi and 260° C. at a flow rate of 5 liters/min. The reaction products were passed through a condenser where alcohols and liquid hydrocarbons could condense. Gaseous hydrocarbons were allowed to exit a vent into a fume hood. Gas samples were obtained from a sample port on the exit side of the condenser and analyzed via gas chromatography.

EXAMPLE C

Pressure of 1150 psi

540 grams of catalyst (64% MoS₂/18.4% CoS/17% K₂CO₃supported on crushed alumina beads) were placed in a one liter stainless steel high pressure reactor as in Example B. The actual weight of the active component (MoS₂/CoS/K₂CO₃) of the catalyst was 100 grams. The premixed carbon monoxide and hydrogen gas (CO:H_2;2:1) was passed through the catalyst bed at 1150 psi and 260° C., at 5 liters/min. The reaction products were passed through a condenser where alcohols and liquid hydrocarbons could condense. Gaseous hydrocarbons were allowed to exit through a vent into a fume hood. Gas samples were obtained from a sample port on the exit side of the condenser and analyzed via gas chromatography.

EXAMPLE D

Pressure of 1500 psi

The catalyst in this experiment was the same as the catalyst in Example B and C. The premixed gas (CO:H₂1:2) was passed through the catalyst bed at 1500 psi and 260° C., at a flow rate of approximately 3 liters per minute. The reaction products were passed through a condenser where alcohols and liquid hydrocarbons could condense. Gaseous hydrocarbons were allowed to exit a vent into a fume hood. Gas samples were obtained from a sample port on the exit side of the condenser for analysis via gas chromatography.

EXAMPLE E

Pressure of 1500 psi

390 grams of catalyst (61% MoS₂/24.6% CoS/14% K₂CO₃supported on crushed alumina beads) were placed in a one liter stainless steel high pressure reactor. The actual weight of the active component (MoS₂/CoS/K₂CO₃) of the catalyst was 180 grams. The premixed carbon monoxide and hydrogen gas (CO:H_2;1:2) was passed through the catalyst bed at 1500 psi and 260° C., at a flow rate of 2.5 liters/min. The reaction products were passed through a condenser where alcohols and liquid hydrocarbons could condense. Gaseous hydrocarbons were allowed to exit a vent into a fume hood. Gas samples were collected from a gas sampling port prior to the gas entering the condenser and a sample from the sample port on the exit side of the condenser for analysis via gas chromatography.

EXAMPLE F

Pressure of 1500 psi

The catalyst was the same as the catalyst in Example E. The premixed gas (CO:H_2;1:2) was passed through the catalyst bed at 1500 psi and 260° C. at a flow rate of approximately 5 liters/min. The reaction products were passed through a condenser where alcohols and liquid hydrocarbons could condense. Gaseous hydrocarbons were allowed to exit trough a vent into a fume hood. Gas samples were collected from a gas sampling port prior to the gas entering the condenser and a sample from the sample port on the exit side of the condenser for analysis via gas chromatography.

TABLE 1

Summary of the Reaction Conditions

						Flow
Ex-	Catalyst	Catalyst	Temp.	Pressure		rate
periment	type	wt. (g)	(° C.)	(psi)	CO:H2	(l/min)

A	MoS₂/CoS/	50	260	500	1:1	5
	K₂CO₃
B	MoS₂/CoS/	100	260	500	2:1	5
	K₂CO₃
C	MoS₂/CoS/	100	260	1000	2:1	5
	K₂CO₃
D	MoS₂/CoS/	100	260	1500	1:2	3
	K₂CO₃
E	MoS₂/CoS/	180	260	1500	1:2	2.5
	K₂CO₃
F	MoS₂/CoS/	180	260	1500	1:2	5
	K₂CO₃

For all of the experiments the reactants and products were analyzed by using a gas chromatograph equipped with a thermal conductivity detector (TCD) and a flame ionization detector (FID). Concentration of carbon monoxide and hydrogen were determined by the TCD detector and the alcohols and the hydrocarbons were analyzed via the FID detector.
Experiment A
50 grams of MoS₂/CoS/K₂CO₃catalyst at 260° C., 500 psi pressure and 1:1 CO:H₂molar feed ratio was used for the reaction carried out in Example A. A sample of the gas exiting from the condenser was obtained and analyzed via the GC. The analysis of the gas stream is presented in Tables 2, 3 and 4. About 1 gram of liquid was collected from the condenser. A sample of the liquid was analyzed by evaporation of the liquid in a gas bulb and then a gas sample out of the gas bulb was analyzed via the GC. The results are shown in table 2, 3 and 4. Mixed hydrocarbons and alcohols were found to be formed.
The GC data was used to calculate percent weights based on peak area ratios with the usual adjustments for the detector relative sensitivity to the different compounds. There was found about 1.63% weight ratio of the carbon monoxide and 0.03% of hydrogen were unreacted. This resulted in a high concentration of the hydrocarbons in the product. The initial starting composition 1:1 volume ratio is actually a 28:2 weight ratio (molecular weight ratio of equal moles of CO to H₂). The initial weight ratio was 14:1 and in later experiments the weight ratio was 54:1. The hydrogen has been used preferentially.

TABLE 2

Weight Ratios of Produced Alcohols Experiment A

Alcohols in the	% wt. ratios in the	% wt. ratios in the
Product	liquid sample	gas sample

Methanol	20	12
Ethanol	50	20
Propanol	30	23
Isopropanol	N/D	45
Butanol	N/D	N/D

TABLE 3

Weight Ratios of Produced Hydrocarbons Experiment A

Hydrocarbons in the	% wt. ratios in the	% wt. ratios in
Product	liquid sample	the gas sample

Methane	N/D	53
Ethane	N/D	4
Ethylene	N/D	27
Acetylene	N/D	3
Propane	N/D	10
Propylene	N/D	3

TABLE 4

Weight Ratios of Unreacted Feed Stock Experiment A

	% wt. ratios in the	% wt. ratios in
Reactants	liquid sample	the gas sample

Hydrogen	0.00	1.8
Carbon Monoxide	0.00	98.2

The reaction was run at relatively low pressure, 500 psia. The catalyst showed reduced efficacy after several hours.
Experiment B
100 grams of MoS₂/CoS/K₂CO₃catalyst at 260° C., 500 psi pressure and 2:1 CO:H₂molar feed ratio were used for Experiment B. A sample of the gas exiting from the condenser was obtained and analyzed via the GC. The use of more catalyst (providing more reaction surface) and higher ratio of carbon monoxide to hydrogen yielded higher concentration of the higher alcohols in the product in comparison to the gas product from Experiment A. Results obtained are presented in Tables 5 through 7. The gas stream exiting the condenser was sampled for analysis of the produced alcohols. About equal molar ratio of carbon monoxide and hydrogen was left unreacted (Table 7). These conditions favored both the higher alcohols and the higher hydrocarbons.

TABLE 5

Weight Ratios of Produced Alcohols Experiment B

	Alcohols in the	% wt. ratios in the gas
	product	sample

	Methanol	0.2
	Ethanol	9.4
	Propanol	30
	Isopropanol	2.3
	Butanol	54
	tert-Butanol	4.7

TABLE 6

Weight Ratios of Produced Hydrocarbons Experiment B

	Hydrocarbons in the	% wt. ratios in the
	product	gas sample

	Methane	20.6
	Ethane	2
	Ethylene	28.8
	Acetylene	6.3
	Propane	26
	Propylene	16

TABLE 7

Weight Ratios of Unreacted Feedstock in the gas product Experiment B

		% wt. ratios in the
	Reactants	gas sample

	Hydrogen	43
	Carbon Monoxide	57

This experiment was run also at 500 psia and exhibited the same retardation of efficacy as seen in Experiment .A
Experiment C
The same catalyst bed was used in this experiment as in Experiment B. The reaction was carried out at a higher pressure (1000 psi). The gas exiting from the condenser was sampled and analyzed via the GC. There were higher yields of hydrocarbons and a lower yield of alcohols when compared to Experiment B. The results from Experiment C are presented in Tables 8 through 10.

TABLE 8

Weight Ratios of Produced Alcohols Experiment C

	Alcohols in the	% wt. ratios in the gas
	Product	sample

Methanol

	0
	Ethanol	33.8
	Propanol	26.9
	Isopropanol	11.5
	Butanol	27.8
	tert-Butanol	0

TABLE 9

Weight Ratios of Produced Hydrocarbons Experiment C

	Hydrocarbons in	% wt. ratios in the gas
	the product	sample

	Methane	31.2
	Ethane	2.6
	Ethylene	29
	Acetylene	5.2
	Propane	22.5
	Propylene	9.3

TABLE 10

Weight Ratios of Unreacted Feedstock Experiment C

		% wt. ratios in the
	Reactants	gas sample

	Hydrogen	64
	Carbon Monoxide	36

Experiment D
The catalyst bed from Experiments B and C was utilized. The reaction's pressure was 1500 psi with a 1:2 CO:H₂molar feed ratio. The gas exiting from the condenser was sampled and analyzed via the GC. Results for Experiment D are presented in Tables 11 through 13. Formation of alcohols (methanol and ethanol) only occurred with no hydrocarbon formation. In this experiment there was a higher yield of methanol than ethanol.

TABLE 11

Weight Ratios of Produced Alcohols Experiment D

	Alcohols in the	% wt. ratios in the
	Product	gas sample

	Methanol	83
	Ethanol	17
	Propanol	N/D
	Isopropanol	N/D
	Butanol	N/D
	tert-Butanol	N/D

TABLE 12

Weight Ratios of Produced Hydrocarbons Experiment D

	Hydrocarbons in	% wt. ratios in the
	the product	gas sample

	Methane	N/D
	Ethane	N/D
	Ethylene	N/D
	Acetylene	N/D
	Propane	N/D
	Propylene	N/D

TABLE 13

Weight Ratios of Unreacted Feedstock Experiment D

		% wt. ratios in
	Reactants	the gas sample

	Hydrogen	23
	Carbon Monoxide	77

Experiment E
180 grams of MoS₂/CoS/K₂CO₃catalyst at 260° C., 1500 psi pressure and 1:2 CO:H₂molar feed ratio was used in Experiment E. Gas samples were collected after the catalytic reactor 6 and after the condenser 7. The samples were analyzed via the GC as previously. Results are presented in Tables 14 through 16.

TABLE 14

Weight Ratios of Produced Alcohols Experiment E

	% wt. ratios in the	% wt. ratios in the
Alcohols in the	gas sample After	gas sample After
Product	the reactor	the Condenser

Methanol	53.4	62
Ethanol	3.2	3
Propanol	14.3	14
Isopropanol	29.1	21
Butanol	N/D	N/D

TABLE 15

Weight ratios of Produced Hydrocarbons Experiment E

		% wt. ratios in
	% wt. ratios in the	the gas sample
Hydrocarbons in the	gas sample After	After the
Product	the Reactor	Condenser

Methane	87.1	91.8
Ethane	0.01	0.3
Ethylene	0.6	1.3
Acetylene	0.7	3.4
Propane	0.35	1.3
Propylene	0.1	1.4

TABLE 16

Weight Ratios of Unreacted Feedstock Experiment E

	% wt. ratios in the	% wt. ratios in the
	gas sample After	gas sample After
Reactants	Reactor	the Condenser

Hydrogen	69.2	95
Carbon Monoxide	30.7	5

Experiment F
The reaction conditions for Experiment F were 180 grams of MoS₂/CoS/K₂CO₃catalyst at 260° C., 1500 psi pressure and 1:2 CO:H₂molar feed ratio. Gas samples were collected after the catalytic reactor 6 and after the condenser 7. Both samples were analyzed via the GC. Results are presented in Tables 17 through 19.

TABLE17

Weight Ratios of Produced Alcohols Experiment F

	% wt. ratios in the	% wt. ratios in the
Alcohols in the	gas sample After	gas sample After
Product	the Reactor	the Condenser

Methanol	100	72
Ethanol	N/D	20
Propanol	N/D	4
Isopropanol	N/D	4
Butanol	N/D	N/D

TABLE 18

Weight Ratios of Produced Hydrocarbons Experiment F

Methane	96.0	93.5
Ethane	0.2	0.4
Ethylene	1.0	1.4
Acetylene	0.8	1.4
Propane	0.4	0.7
Propylene	1.6	2.5

TABLE 19

Weight Ratios of Unreacted Feedstock Experiment F

		% wt. ratios in
	% wt. ratios in the	the gas sample
	gas sample After	After the
Reactants	the Reactor	Condenser

Hydrogen	43.4	27
Carbon Monoxide	56.6	73

For the formation of alcohols it was found that high pressure was important to obtain the required concentrations. Pressures below 1500 psi resulted in the formation of hydrocarbons. Unexpectedly it was found that the reaction catalyzed by MoS₂/K₂CO₃was more effective in the formation of longer chain alcohols as compared to the MoS₂/CoS/K₂CO₃catalyst that made more methanol.
It was discovered that the specific catalyst ratios used in these experiments are critical to produce the desired mixed alcohol stream that has the highest concentration of ethanol. The ratio was between 61-64% MoS₂, 18.4-24.6% CoS₂and 14-17% K₂CO₃. Surprisingly a reduction in CoS₂favored longer chain length alcohols.

Claims

1. An energy self sufficient process for the production of mixed alcohols from components of municipal solid waste, which comprises:

gasifying combustible portions of municipal solid waste producing a synthesis gas having CO and hydrogen at temperature at around or above 700° C.;

sending portion of said synthesis gas to a boiler or a turbine wherein excess electricity and heat produced operates process equipment;

sending remainder of said synthesis gas to a gas conditioning system reducing temperature and increasing the pressure of said synthesis gas;

sending the synthesis gas from said gas conditioning system to a catalytic conversion system producing said mixed alcohols;

sending unconverted (excess/unused/unneeded) synthesis gas back to said boiler or said turbine;

condensing product fluid from said catalytic conversion system; and

separating said mixed alcohols from hydrocarbons and other combustible liquids wherein waste liquids from condensing step are regasified.

2. The process of claim 1 further comprising maintaining supercritical pressure for the synthesis gas reaction mixture within the catalytic conversion system.

3. The process of claim 1 further comprising maintaining supercritical temperature for the synthesis gas reaction mixture within the catalytic conversion system.

4. The process of claim 2 further comprising:

monitoring the gas and liquid compositions from the catalytic reactor; and

adjusting the pressure to maintain a supercritical state.

5. The process of claim 3 comprising:

monitoring the gas and liquid compositions from the catalytic reactor; and

adjusting the temperature to maintain a supercritical state.

6. An energy self sufficient process for the production of mixed alcohols and pipeline quality natural gas from components of municipal solid waste, which comprises: gasifying combustible portions of municipal solid waste producing a synthesis gas having methane, lower hydrocarbons, CO and hydrogen at temperature at around or above 700° C.;

sending residual from alcohol producing unit to a gas conditioning system to produce pipeline quality gas; and

condensing product fluid from said catalytic conversion system.

7. The process of claim 6 further comprising maintaining supercritical pressure for the synthesis gas reaction mixture within the catalytic conversion system.

8. The process of claim 6 further comprising maintaining supercritical temperature for the synthesis gas reaction mixture within the catalytic conversion system.

9. The process of claim 7 further comprising:

monitoring the gas and liquid compositions from the catalytic reactor; and

adjusting the pressure to maintain a supercritical state.

10. The process of claim 8 comprising:

monitoring the gas and liquid compositions from the catalytic reactor; and

adjusting the temperature to maintain a supercritical state.