Eugene P Columbus

Performance and emissions of a spark-ignited engine driven generator on biomass based syngas

The emergence of biomass based energy warrants the evaluation of syngas from biomass gasification as a fuel for personal power systems. The objectives of this study were to determine the performance and exhaust emissions of a commercial 5.5 kW generator modified for operation with 100% syngas at different syngas flows and to compare the results with those obtained for gasoline operation at same electrical power. The maximum electrical power output for syngas operation was 1392 W and that for gasoline operation was 2451 W. However, the overall efficiency of the generator at maximum electrical power output for both the fuels were found to be the same. The concentrations of CO and NO(x) in the generator exhaust were lower for the syngas operation, respectively by 30-96% and 54-84% compared to the gasoline operation. However, the concentrations of CO(2) in the generator exhaust were significantly higher by 33-167% for the syngas operation.

Pilot scale fiber separation from distillers dried grains with solubles (DDGS) using sieving and air classification

Distillers dried grains with solubles (DDGS), the coproduct of fuel ethanol production from cereal grains like corn, is mainly used as cattle feed and is used at low inclusion levels in poultry and swine diets because of high fiber content. Elusieve process, the combination of sieving and air classification (elutriation), was developed in laboratory scale to separate fiber from DDGS to result in a low fiber product which would be more suitable for poultry and swine. In this pilot scale study, DDGS was sieved at a rate of 0.25 kg/s (1 ton/h) into four sieve fractions using a sifter and the three largest sieve fractions were air classified using aspirators to separate fiber on a continuous basis. Results were similar to laboratory scale. Nearly 12.4% by weight of DDGS was separated as Fiber product and resulted in two high protein products that had low fiber contents. Payback period for the Elusieve process in an existing dry grind plant processing corn at the rate of 2030 metric tonnes/day (80,000 bushels/day) would be 1.1 yr.

Syn-gas quality evaluation for biomass gasification with a downdraft gasifier.

The purpose of this study was to examine the operation of a commercially manufactured research-scale downdraft gasifier, the Renewable Fuel Gas Generator, Community Power Corporation, Littleton, Colorado. An experimental study of hardwood chip gasification was run under various operating conditions to determine the effects on the syn-gas (synthesis gas) produced in the process. The resulting syn-gas had an average LHV (low heating value) of 5.79 ±0.52 MJ Nm-3 (Nm3 stands for normal cubic meter, i.e., volume of a gas measured at standard temperature and pressure), tar concentration of 14.06 ±8.54 mg Nm-3, and particulate concentration of 3.05 ±1.79 mg Nm-3. Syn-gas at this level of quality is acceptable for use as a fuel for internal combustion engines and also for other purposes. The process was also very efficient, with a hardwood conversion rate of 2.37 ±0.24 Nm3 kg-1 and a carbon conversion rate of 98.01% ±0.53%. The gasifiers grate temperature had no evident effects on syn-gas quality and conversion rate within a range of 740°C to 817°C. The particulate contents in pre-filter syn-gas significantly increased when the gas flow rate changed from 36 to 56 Nm3 h-1, but no other syn-gas attributes were significantly affected by gas flow rate. When the moisture content of hardwood chips increased, tar content of post-filter syn-gas significantly increased and CO content significantly decreased, but no other attributes were affected. Overall the system, which has extensive electronic controls based on temperatures and pressures at numerous locations, produced a remarkably consistent high-quality syn-gas regardless of input parameters.

Application of 3D scanned imaging methodology for volume, surface area, and envelope density evaluation of densified biomass.

Measurement of volume, surface area, and density is an essential for quantifying, evaluating, and designing the biomass densification, storage, and transport operations. Acquiring accurate and repeated measurements of these parameters for hygroscopic densified biomass are not straightforward and only a few methods are available. A 3D laser scanner was used as a measurement device and the 3D images were analyzed using image processing software. The validity of the method was verified using reference objects of known geometry and the accuracy obtained was in excess of 98%. Cotton gin trash briquettes, switchgrass pellets, switchgrass cubes, hardwood pellets, and softwood chips were tested. Most accurate results of the volume and surface area required the highest possible resolution of the scanner, which increased the total scan-process times, and image file size. Physical property determination using the 3D scanning and image analysis is highly repeatable (coefficient of variation <0.3%), non-invasive, accurate, and alternative methodology. The various limitations and merits of the developed method were also enumerated.

Economic Evaluation of Syngas Production: Model Development and Analysis

The objective of this study was to develop and apply an economic model to predict the unit cost of syngas production from a micro-scale bio-gasification facility. The economic model was programmed in C++ and developed using a parametric-cost approach, which included processes to calculate the total capital costs and the total operating costs of a bio-gasification facility. The model used data measured from the bio-gasification facility at Mississippi State University. The modeling results showed a unit cost and energy cost of syngas production of

Evaluation of Syngas Storage Under Different Pressures and Temperatures

1.258 Nm-3 and

Experimental Study of a Downdraft Gasifier

0.217 MJ-1, respectively, for a 60 Nm3 h-1 bio-gasifier capacity. The operating cost was determined to be a large proportion of the total production cost, in which equipment purchase cost and labor cost were a major part of the total capital cost and the total operating cost, respectively. When the production capacity increased from 60 to 2,400 Nm-3 h-1 with a higher operating mode, the total annual production cost increased while the syngas unit cost decreased. Sensitivity analysis of the model results indicated that equipment purchase cost ranked highest, followed by employee pay rate, feedstock price, loan life, interest rate, electricity price, and waste treatment price. The unit cost of syngas production increased with the increase of all parameters with the exception of loan life. The loan life and annual interest rate showed a non-linear relationship, while the other parameters showed a linear relationship with percent changes in the unit cost of syngas production. The economic model and analysis techniques developed in this study were found to be useful and can be applied in other similar conditions as needed.

Design and testing of a LabView-controlled catalytic packed-bed reactor system for production of hydrocarbon fuels.

The objective of this research was to study the syngas storage characteristics in terms of any variation in composition of H2, CO, CH4, CO2, and N2 under two pressures (2758 and 8274 kPa) and three temperatures (-288K, 288K, and 318K). We also evaluated tar, particulate, and moisture content of the stored syngas. Syngas generated from a down-drift gasifier using 95% hardwood chips as the feedstock contained an average of 17.0% H2, 23.9% CO, 1.4% CH4, 11.0% CO2, and 46.7% N2. The compositional elements of the stored syngas under different pressures and temperatures were periodically determined for a three-week period of storage. The statistic model of a single-factor experiment with repeated measures on treatments was used to perform the data analysis with the SAS program. Statistic analysis revealed that the temperature range from -288 to 318K had no effects statistically on the major syngas composition at the tested pressures. Pressures up to 8274 kPa had no effects statistically on the major syngas composition at the tested temperatures. The variations of the syngas components measured were probably due to analysis and instrumental errors. At both pressures, the CO composition had a bigger variation than other components and, as the temperature varied, the CO composition varied more than the other components. Mechanisms of the relatively bigger variation of the CO concentration were not fully understood and may be partially contributed to the pressure and temperature variations. Tars were detected in the storage cylinders after washing with acetone solution, which indicated that the tars were deposited on the inside wall of each storage cylinder. The amount of tars was correlated with the temperature. The low storage temperature precipitated more tars under pressure during storage. Thus this study showed that syngas could be stored with no major adverse affects caused by temperatures of -15°C to 45°C. Also, pressures up to 8274 kPa had no effect on syngas composition at the tested temperatures. Additional studies should be conducted on deposition of tars at low temperatures during storage, condensation of heavy hydrogen carbons, quantification of tar deposited on the storage surface, and deterioration of the storage surface (especially when sulfur compounds exit in syngas).

Scale-Up of Liquid Hydrocarbon Production using Gasified Biomass

In order for biomass gasification to be successfully implemented to provide energy or raw material for the chemical industry, the quality of synthesis gas (syngas) produced is critical. To examine the effects of operational parameters on syngas quality and biomass conversion rate, an experimental study of hardwood chip gasification in a downdraft gasifier system was conducted. This gasifier was run under various conditions to produce syngas, which had an average low heating value of 5.79 ± 0.52 MJ/ Nm3, tar concentration of 14.06 ± 8.54 mg/Nm³, particulate(>0.7im) concentration of 3.05 ± 1.79 mg/Nm³, hardwood chip conversion rate of 2.37±0.24 Nm³/kg, and carbon conversion rate of 98.01 ± 0.53%. This syngas is of acceptable quality to be used as a fuel source for internal combustion engine operations. The gasifier’s grate temperature had no evident effects on syngas quality and conversion rate within a range of 740 to 817 oC. The particulate contents in pre-filtered syngas significantly increased when the gas flow rate changed from 36 to 56 Nm3/h. When the moisture content of hardwood chips increased, tar content of post-filtered syngas significantly increased, and carbon monoxide content significantly decreased.

Liquid Hydrocarbon Production over Mo/HZSM-5 Using Gasified Biomass

Gasified woody biomass (producer gas) was converted over a Mo/H+ZSM-5 catalyst to produce gasoline-range hydrocarbons. The effect of contaminants in the producer gas showed that key retardants in the system included ammonia and oxygen. The production of gasoline-range hydrocarbons derived from producer gas was studied and compared with gasoline-range hydrocarbon production from two control syngas mixes. Certain mole ratios of syngas mixes were introduced into the system to evaluate whether or not the heat created from the exothermic reaction could be properly controlled. Contaminant-free syngas was used to determine hydrocarbon production with similar mole values of the producer gas from the gasifier. Contaminant-free syngas was also used to test an ideal contaminant-free synthesis gas situation to mimic our particular downdraft gasifier. Producer gas was used in this study to determine the feasibility of using producer gas to create gasoline-range hydrocarbons on an industrial scale using a specific Mo/H+ZSM-5 catalyst. It was determined that after removing the ammonia, other contaminants poisoned the catalyst and retarded the hydrocarbon production process as well.