Saqib Mukhtar

FIXED-BED GASIFICATION OF FEEDLOT MANURE AND POULTRY LITTER BIOMASS

The U.S. cattle industry is a

Transient-State Oxygen Diffusion Through Undisturbed Soil Columns

175 billion industry with an estimated 100 million cattle. About 10 million head of nthese cattle are in feedlots producing harvestable manure. At the same time, the U.S. poultry industry is the world’s largest nproducer and exporter of poultry meat. Not surprisingly, one outcome is the production of a large quantity of manure byproducts, nwith approximately 60 million tons of dry harvestable animal manure produced annually from confined livestock and npoultry. This article describes a method of extracting energy from feedlot manure or poultry litter biomass either individually nor combined with each other. High-ash (approximately 45% dry weight basis) feedlot biomass (HFB) and poultry litter biomass n(HLB) were gasified in a 10 kW (thermal) fixed-bed, counter-current atmospheric pressure gasifier to generate a mixture nof combustible gases that could be further burned to generate heat. This article discusses the effect of the biomass particle nsize on the composition of the product gas leaving the gasifier, the temperature profiles in the fixed bed, and the ash fusion nof HFB and HLB during gasification. Air-blown gasification of the biomass fuels yielded a low-Btu gas with a higher heating nvalue of 4.4 ±0.4 MJ/m3 and an average product gas composition (dry basis) of H2: 5.8 ±1.7%, CO: 27.6 ±3.6%, CH4: 1.0 n±0.5%, CO2: 6.7 ±4.3%, and N2: 59.0 ±7.1%. The overall average equivalence ratio was 2.82 ±0.43 on a dry ash-free nbasis. The experimental results also show that high-alkaline content fuels, such as HLB (Na2O + K2O = 16.7% of ash), can nbe gasified by blending with lower-alkaline content fuels, such as HFB (6.0%), to reduce agglomeration in the fuel bed nwithout significantly affecting the heating value of the product gas. The gasification of HLB and HFB yields a low-Btu gas nthat can be combusted to generate heat for steam or power generation. The process has potential for reducing transportation ncosts for traditional cropland-based manure application in some regions.

An Investigation of Ammonia Extraction from Liquid Manure Using a Gas-Permeable Membrane

ABSTRACT The transport of oxygen from the atmosphere to the soil as a function of soil depth and time has been analyzed theoretically. Laboratory experiments were conducted to collect data on relative oxygen concentrations as a function of tillage, time, and soil depth by using two undisturbed soil columns. Data collected from these experiments were used to verify mathematical models describing the nonsteady state diffusion of oxygen into the soil. The results of this study showed that the values of relative oxygen concentrations predicted by the mathematical model compared well with the experimental data.

Removing ammonia from air with a constant pH, slightly acidic water spray wet scrubber using recycled scrubbing solution

Abstract: Pollution of air, soil and water caused by excessive ammonia (NH3) emission and deposition from animal manure is as an environmental concern. Gas-permeable membranes (GPM) may provide a solution for controlling NH3 emission to the environment by extracting it from liquid manure and potentially using the recovered NH3 as fertilizer. For this purpose, four lab-scale experiments were conducted to investigate the capture and recovery of NH3 from liquid manure by circulating an acid solution through a tubular GPM submerged into the liquid dairy manure. During these experiments, the depth of liquid manure in chambers of different dimensions and the tubular membrane parameters including diameter, length and pore size were held constant in order to study the effect of acid-filled membrane on NH3 extraction from different surface areas (1X, 2X, 4X, and 8X) of liquid manure. Results show that nearly 50% of the liquid manure NH3 measured prior to the start of each experiment from all but 8X chamber was captured in less than 20 days by acid-filled membranes. Also, NH3 extraction by the GPM system from liquid manure and NH3 gain in acidic solution were linearly correlated. The study showed that the experiment with the 4X chamber resulted in optimum NH3 extraction using the GPM system.

RENEWABLE ENERGY AND ENVIRONMENTAL SUSTAINABILITY USING BIOMASS FROM DAIRY AND BEEF ANIMAL PRODUCTION

Previous research on wet scrubbers has only studied highly acidic scrubbing solutions because of their high ammonia capture efficiencies; however, the high acidity created practical problems. Lower acidity solutions would reduce corrosion, maintenance, and cost; however, designers may need to use strategies for increasing scrubber effectiveness, such as using lower air velocities. The objective of this study was to determine if a spray scrubber with slightly acidic and higher pH scrubbing solution (pH from 2 to 8) could effectively remove NH3 from NH3 laden air (such as animal building exhaust air), and also collect this valuable resource for later use as a fertilizer. A bench-scale spray wet scrubber treated 20 ppmv NH3/air mixture in a countercurrent contact chamber. First, the solution pH was varied from 2 to 8 while maintaining constant air velocity at 1.3 m•s–1. Next, air velocity was increased (2 and 3 m•s–1) while solution pH remained constant at pH6. At 1.3 m•s–1, NH3 removal efficiencies ranged between 49.0% (pH8) and 84.3% (pH2). This study has shown that slightly acidic scrubbing solutions are a practical means of removing ammonia from air especially if the scrubber is designed to increase collisions between solution droplets and NH3 molecules. The NH3 removed from the air was held in solution as NH4+ and accumulates over time so the solution should be an excellent fertilizer.

Application of Diluted Sulfuric Acid for Manure Ammonia Extraction Using a Gas-Permeable Membrane

The Texas Panhandle is regarded as the Cattle Feeding Capital of the World, producing 42% of the fed beef cattle in the United States within a 200-mile radius of Amarillo generating more than 5 million tons of feedlot manure/year. Apart from feedlots, the Bosque River Region in Erath County, just north of Waco, Texas with about 110,000 dairy cattle in over 250 dairies, produces 1.8 million tons of manure biomass (excreted plus bedding) per year. While the feedlot manure has been used extensively for irrigated and dry land crop production, most dairies, as well as other concentrated animal feeding operations (CAFOs), the dairy farms utilize large lagoon areas to store wet animal biomass. Water runoff from these lagoons has been held responsible for the increased concentration of phosphorus and other contaminates in the Bosque River which drains into Lake Waco - the primary source of potable water for Wacos 108,500 people. The concentrated animal feeding operations may lead to land, water, and air pollution if waste handling systems and storage and treatment structures are not properly managed. Manure-based biomass (MBB) has the potential to be a source of green energy at large coal-fired power plants and on smaller-scale combustion systemsmorexa0» at or near confined animal feeding operations. Although MBB particularly cattle biomass (CB) is a low quality fuel with an inferior heat value compared to coal and other fossil fuels, the concentration of it at large animal feeding operations can make it a viable source of fuel. The overall objective of this interdisciplinary proposal is to develop environmentally benign technologies to convert low-value inventories of dairy and beef cattle biomass into renewable energy. Current research expands the suite of technologies by which cattle biomass (CB: manure, and premature mortalities) could serve as a renewable alternative to fossil fuel. The work falls into two broad categories of research and development. Category 1 - Renewable Energy Conversion. This category addressed mostly in volume I involves developing. Thermo-chemical conversion technologies including cofiring with coal, reburn to reduce nitrogen oxide (NO, N2O, NOx, etc.) and Hg emissions and gasification to produce low-BTU gas for on-site power production in order to extract energy from waste streams or renewable resources. Category 2 - Biomass Resource Technology. This category, addressed mostly in Volume II, deals with the efficient and cost-effective use of CB as a renewable energy source (e.g. through and via aqueous-phase, anaerobic digestion or biological gasification). The investigators formed an industrial advisory panel consisting fuel producers (feedlots and dairy farms) and fuel users (utilities), periodically met with them, and presented the research results; apart from serving as dissemination forum, the PIs used their critique to red-direct the research within the scope of the tasks. The final report for the 5 to 7 year project performed by an interdisciplinary team of 9 professors is arranged in three volumes: Vol. I (edited by Kalyan Annamalai) addressing thermo-chemical conversion and direct combustion under Category 1 and Vol. II and Vol. III ( edited by J M Sweeten) addressing biomass resource Technology under Category 2. Various tasks and sub-tasks addressed in Volume I were performed by the Department of Mechanical Engineering (a part of TEES; see Volume I), while other tasks and sub-tasks addressed in Volume II and IIII were conducted by Texas AgriLife Research at Amarillo; the TAMU Biological and Agricultural Engineering Department (BAEN) College Station; and West Texas A and M University (WTAMU) (Volumes II and III). The three volume report covers the following results: fuel properties of low ash and high ash CB (particularly DB) and MB (mortality biomass) and coals, non-intrusive visible infrared (NVIR) spectroscopy techniques for ash determination, dairy energy use surveys at 14 dairies in Texas and California, cofiring of low quality CB with high quality coal, emission results and ash fouling behavior, using CB as reburn fuel for NOx and Hg reduction, gasification of fuels to produce low quality gases, modeling of reburn, pilot scale test results, synthesis of engineering characterization, geographical mapping, a transportation cost study to determine potential handling and transportation systems for co-firing with coal at regional coal-fired power plants, software analyses for the design of off-site manure, pre-processing and storage systems for a typical dairy farm or beef cattle feedlot, recursive production functions/systems models for both cattle feedlots, systems modeling, stocks and flows of energy involved in the CAFO system, feedback from an Industry Advisory Committee (IAC) to the investigators on project direction and task emphasis and economics of using CB as cofiring and reburn fuel.«xa0less

Comparison of Greenhouse Gas Emissions from Ground Level Area Sources in Dairy and Cattle Feedyard Operations

Tubular gas-permeable membrane (GPM) provides an alternative solution for ammonia (NH3) mitigation and recovery from liquid animal manure. A set-up consisting of a closed dairy liquid manure (LM) chamber, two sulfuric acid (H2SO4) flasks and two GPM systems was fabricated in order to investigate NH3 extraction processes using diluted H2SO4 solutions (pH values between 2 and 5.4). One GPM system was submerged below the LM surface and the other was suspended above LM surface in the headspace of the chamber. Ammonia from dairy LM was extracted and captured in acidic solution by circulating the diluted H2SO4 through both GPM systems. Results showed that the extraction of NH3 by both systems continued for few days, even though pH of the circulating acidic solution in the tubular GPM increased above the neutral pH value. By then, between 5% and 13% of the initial NH3 concentration of untreated LM were extracted by the circulating acidic solution in both systems. It was observed that the pH of acidic solution increased very quickly; especially for more diluted acid solutions. Among all experiments, the diluted acid with pH of 2 had the greatest NH3 removal and recovery as ammonium sulfate (NH4)2SO4, a potential fertilizer. However, none of the experiments with diluted acidic solutions resulted in greater extraction and recovery of NH3 from LM as compare to the strong acid (pH<0.4) used in a previous study.

Electrolyzed Water Spray Scrubber for Removing Ammonia from Air

A protocol that consisted of an isolation flux chamber and a portable gas chromatograph was used to directly quantify greenhouse gas (GHG) emissions at a dairy and a feedyard operation in the Texas Panhandle. Field sampling campaigns were performed 5 days in a week during daylight hours from 9:00 to 7:00 pm each day. The objective of this research was to quantify and compare GHG emission rates (ERs) from ground level area sources (GLAS) at dairy and cattle feedyard operations during the summer. A total of 74 air samples using flux chamber were collected from the barn (manure lane and bedding area), loafing pen, open lot, settling basin, lagoons, and compost pile within the dairy operation. For the cattle feedyard, a total of 87 air samples were collected from four corner pens of a large feedlot, runoff holding pond, and compost pile. Three primary GHGs (methane, carbon dioxide, and nitrous oxide) were measured and quantified from both operations. The aggregate estimated ERs for CH4, CO2, and N2O were 836, 5,573, 3.4 g hd-1d-1 (collectively 27.5 kg carbon dioxide equivalent (CO2e) hd-1 d-1), respectively, at the dairy operation. The aggregate ERs for CH4, CO2, and N2O were 3.8, 1,399, 0.68 g hd-1d-1 (1.7 kg CO2e hd-1 d-1), respectively, from the feedyard. Aggregate CH4, CO2, and N2O ERs at the dairy facility were about 219, 4 and 5 times higher, respectively, than those at the feedyard.