Heat Utilization Factor Research Articles

Development of Mobile Dryer for Freshly Harvested Paddy

Presently, due to an increase in usage of large scale mechanical threshers and combine harvesters, moisture content of freshly harvested paddy is being high as much as 18-24%. The mechanical threshers or combine harvesters with elevated capacity enable for both harvesting and threshing at once. Thus the paddy harvested all over persists with high moisture content that affects adversely in unit operations of paddy processing such as cleaning, storing, and milling. The research was conducted to overcome this problem by developing a mobile paddy dryer that can be used at field level for freshly harvested paddy. A mobile dryer, one ton capacity, was developed and tested for drying freshly harvested paddy. The performance of the mobile dryer was evaluated in terms of overall thermal efficiency, heat utilization factor, coefficient of performance, total heat efficiency and head rice yields. The overall thermal efficiency of this dryer was 46.83%. The average heating efficiencies namely heat utilization factor and total heat efficiency were 0.82 and 0.72 respectively. The coefficient of performance of the developed dryer was 0.18. The head rice yields of freshly harvested paddy after drying at 60°C air temperature was of 73.78%. The overall drying performance of the dryer was found to be good.

Use of combined steam-water and organic rankine cycles for achieving better efficiency of gas turbine units and internal combustion engines

Innovative concepts of recovering waste heat using low-boiling working fluids, due to which the the efficiency can be increased to 28–30%, are presented. If distributed generation of electricity or combined production of heat and electricity is implemented, the electrical efficiency can reach 58–60% and the fuel heat utilization factor, 90%.

Drying characteristics of foamed alphonso mango pulp in a continuous type foam mat dryer

Preliminary trials were conducted for foam mat drying of alphonso mango pulp using batch type cabinet dryer. From the trial, it was observed that the foamed mango pulp using egg albumen (10%) as foaming agent with methyl cellulose (0.5%) as stabilizing agent, dried at 60 °C with 1 mm foam thickness was found to be the best. For this foamed pulp, parameters such as viscosity (5.7 ± 0.06 Pa s), stickiness (18.9 ± 0.1 g force) and specific heat (3.66 ± 0.02 kJ/kg °C) values were determined. The drying study showed that the time required to dry the fresh (non-foamed) and foamed mango pulps were 75 and 35 min, respectively. Based on the preliminary drying results, a continuous type foam mat dryer (lab model) with a capacity of drying 2.5 kg/day of 8 h was developed to dry the mango pulps. The overall moisture diffusion in fresh and foam dried mango flakes was 5.3 and 9.7 × 10 −9 m 2/s, respectively. Based on the performance evaluation, it was found that foam dried flakes recorded higher heat utilization factor than non-foam dried flakes. Also from the quality analysis, it was observed that the changes were comparatively lower in foam dried flakes than in non-foam dried flakes using continuous type foam mat dryer.

Development of an air recirculating tray dryer for high moisture biological materials

Fruits and vegetables are highly perishable and deterioration in quality and quantity occurs due to poor storage and processing facilities at the production site in developing countries like India. Dehydration of vegetables using a recirculatory dryer is possible but limited, in practice. The recirculatory dryers so far developed have a drawback of non-uniform drying along the length of the trays. Hence an effort was made to solve this problem. A recirculatory cabinet dryer of capacity 5 kg/batch using a central air distribution system was designed and developed. The dryer was tested with blanched potato chips. At a constant air flow rate of 1.5 m 3/ min and 65°C temperature, it took about 3 h time to reduce the moisture content from 856.94% (dry basis) to 9.98% (dry basis). The heat utilization factor (HUF) and thermal heat efficiency (THE) of the developed dryer were found to be 18.94% and 22.16%, respectively.

Applicability of furnace analysis in determination of the performance characteristics of a hot wall furnace fired with sorbent-loaded coal-water fuel

A hot-wall furnace of 40 ft 3 fired with sorbent-loaded coal-water fuels at 1 MMBtu/h was found to generate firing and efficiency (performance) curves in functional agreement with the equations developed in furnace analysis. (In the FPS system, M = 1000 and MM = 1000000. It is based on the Latin prefix, M, as abbreviation for mille.) The present study includes a theoretical correction for the dependence of the firing parameters on excess air due to water in the fuel, and this correction is shown to be supported by test against the experimental results. The complete results show the variation with output of: thermal input (firing curve), thermal (operational) efficiency, heat utilization factor, specific gas enthalpy, and wall loss