PROSPECT OF RICE BRAN OIL PRODUCTION IN BANGLADESH

2010

Bangladesh is currently facing power crisis which has become worse in recent years. The cost of power generation is increased drastically with an unprecedented surge in international fuel price. The rising cost of fuel is the reason to seek the alternative source of fuel. Rice husk, which is a by-product of rice processing, is identified as an important and potential alternative fuel source for generating power. Bangladesh is an agricultural country which is dominated by paddy cultivation. Bangladesh has reportedly over fifty thousand Rice mills -small, medium, large. They process paddy collected from rural areas. The Rice mills use the thermal energy of steam generated in boilers are fired by Rice husk which is globally well known as very convenient source of dry biomass energy of reasonable heat value. In Bangladesh context out of 38 million tons of total biomass produce from agro-residues, Rice husk contributes about 28% by mass. Rice husk is considered to be an environmentally friendly fuel because it can mitigate CO2, SO 2 and NOx emissions when compared with conventional fuel. In this research four major rice processing districts were selected to estimate potential husk available for electricity generation. The selected rice mill clusters are located at Dinajpur, Bogra, Rajshahi and Rangpur. Over hundred numbers of rice mills were surveyed in this research to know about annual paddy processing capacity and surplus amount of husk from the five selected rice processing zones are analyzed. Based on collected data, potential power capacities are estimated in four selected districts considering the steam turbine technology. A systematic approach can give birth to a new industrial sector of Rice husk power production in Bangladesh.

Biomass currently supplies 14% of the worldwide energy consumption whereas in Bangladesh 68-73% with conversion efficiency of less than 10%. The potential of improving its efficiency through novel technologies is very high. Bio energy has significant potential contribution for sustainable energy systems, especially when converted to modern energy carriers such as electricity, gaseous or liquid fuels. On the other hand, it has an important part of today's imperfect energy systems in many sectors that slow development of the society. Maximum rice husk produced by milling process of rice mills in Bangladesh usually burned in the mill boilers to produce process heat for parboiling of paddy rice and excess husk are sold to the market as fuel for cooking purposes and a considerable portion is misused. This husk burning is incomplete, very inefficient as well as not practiced in an environment friendly way. The study recently carried out to find out technological prospects of electricity generation by gasification of extra rice husk at an automatic rice mill with crushing capacity 150 tonnes per day in Naogaon District of Bangladesh. Using 14 tonnes of excess rice husk at studied mill, 470 KW electrical power generation capacity achievement is possible through rated 470 KW rice husk gasifier in combination with dual fuel internal combustion engine. For 10 years project lifetime, considering 350 days yearly operation, the plant can generate 39.48 GWh electricity and cumulative CO 2 emission reduction through this project will be 12236 tonnes. Moreover, surplus power can be sold to local community for community development and thereby considerable revenue earning is possible.

The majority of paddy is still processed through Engelberg hullers in Bangladesh, which are usually low capacity mills with a very high percentage of broken rice for simultaneous both the shelling and polishing operations. This study was conducted to improve the shelling and polishing in such a way that less rice is broken and quality rice can be produced in an economical manner. In this regard, an air blowing type Engelberg rice mill has been developed in the BRRI research workshop based on AutoCAD design during 2012-2013. A cast iron roller is used in the Engelberg rice mill. The sharp and square edge Engelberg roller of the conventional Engelberg rice mill was modified to a curved edge in one side with a less sharp edge to reduce the breakage during milling by reducing the friction and sharing force during milling operation. In the Engelberg rice mill, a round type screen (without ambush) is normally used which requires higher pressure resulting more breakage. To avoid breakage and get a higher yield, ambush type, round and hexagonal screens were designed for the modified air blowing type Engelberg rice mill. It was found that the hexagonal type screen performs better than the round type. The angle of each corner of the hexagonal screen is 60 0 . In air blowing type of Engelberg rice mill, a blower is used to remove the husk and bran from rice inside the cylinder. The radius of the blower fan is 121 mm. The inlet and outlet radius of the blower is 77 mm. The blower not only cleans the rice from the husk and bran, but also reduces the temperature inside the cylinder, resulting in less breakage and higher head rice recovery as well as high milling yield. The husk and bran collection hopper used in the lower part of the Engelberg rice mill. In the outlet pipe, there is an air hole used to supply air so that the blower can get sufficient air for the suction of husk and bran. The modified rice mill were evaluated and compared with the conventional rice mill. BRRI dhan29 was used as parboiled paddy. The operational cost per hour of the two machines is almost the same, but the capacity of the modified air blowing type Engelberg rice mill is two and half times more than that of the traditional one. To process one ton of paddy by air blowing type mill, about 800 taka is needed, whereas 2,100 taka is needed for processing one ton of paddy with the traditional Engelberg rice mill. However, milling yield also increased by 2%. The modified air blowing type needs only one pass while the Engelberg rice mill needs at least two passes to get the white rice, and almost 1% paddy remains with the end product. With the modified air blowing type Engelberg, rice mill head rice recovery was increased by 1% compared to the traditional Engelberg rice mill. The modified rice mill is a promising technology for small scale farmers and rice traders in Bangladesh.

An effort was made to study the rice processing technology, energy and labour utilization in commercial rice processing mills for parboiled rice. For this purpose 20 selected rice mills of Gapalpur and Parbotipur upazilas were visited and relevant data were collected through field survey conducted during the period from Average total energy used in the rice mills was estimated about 708.5 kWh/t. Of the total energy used, biomass energy comprised 91.74% (650.0 kWh/t), electrical 7.81% (55.3 kWh/t) and manual 0.45% (3.2 kWh/t). The average electrical energy used for a huller and a vibrating sieve was 36.7 kWh/t, whereas average energy used for lighting, fans and water pumps were 6.4, 0.8, 11.4 kWh/t, respectively. Locally made steel boilers and drum boilers were used with husk as fuel. Husk was required at the rate of 150-155 kg husk/t paddy for double steaming. Manual labour utilized in the rice mills averaged 42.77 man-hr/t (3.19 kWh/t). Maximum energy was required for carrying paddy, rice and other by-products in bags or baskets (14.48 manhr/t), followed by manual separation of broken rice (12.11 man-hr/t), mechanical separation of head rice (5.35 man-hr/t), bagging and unbagging (4.04 man-hr/t), drying (4.04 man-hr/t), loading and unloading soaking tank (1.4 man-hr/t), feeding boiler furnace with husk (0.85 man-hr/t), and weighing (0.54 man-hr/t).

Scientific Journal of Agriculture, 2012

With the growth of demand for food crops, especially the rice and quality product, the need for improved technology of paddy processing industry has been realised. This improvement of technology saves post-harvesting losses to some extent. However, the viability of the industry depends on the economics of paddy processing done by different mills. With the help of 92 sample mills (67 modern and 25 traditional), the conversion ratio of rice was found to be 63 percent and 58.7 percent by the modern and traditional mills respectively. Though, the net profit accrued by the modern mills was found to be lesser than the traditional mills, the former is beneficial and preferred than the latter, on the ground of economies of scale and quality of production.

北海道大学農經 …, 2001

Rice bran is a valuable by-product of the rice milling industry, a good natural source of many vital nutrients but has some limitations in food application. It is highly susceptible to rancidity caused by the inherent enzyme lipase and there is an unfounded fear that the rice bran may contain silica in an amount and make it unsuitable for human consumption. In the present investigation, cold treatment was used to extend the shelf life of local variety parboiled rice bran and was also directed to assess the nutritional composition and silica content. The rancidity in term of free fatty acid (FFA) was less increased 0.104 to 0.74 % (7 fold) in cold treated parboiled rice bran than untreated rice bran 0.104 to 2.90 % (28 fold) at the end of 3 months of storage period. The silica content was ranged from 0.34-0.71 % in different fractions of rice bran samples. The nutritional composition of the stabilized rice bran was analyzed that contained 6.54-9.48 % moisture, 7.24-10.63 % ash, 12.26-14.01% proteins, 23.53-27.86 % fats, 2.5-10.10 % fiber, 42.19-45.74 % carbohydrate and 456.54-486.00 Kcal/100g energy. The different fractions of rice bran contained 8 - 14 mg/100 g of Fe, 425 – 940 mg /100 g of Mg, 4.65 – 6.68 mg /100 g of Zn and 35 – 62 mg/ 100 g of Ca. The vitamin B1 (Thiamin), B3 (Niacin) and B6 (Pyridoxine) content ranged from 14 – 24, 275 – 430 and 25 – 42 ppm respectively in different fractions of rice bran. Results indicated that cold treatment might effectively improve the self life of rice bran that contained a good amount of vital nutrients for health benefit and is useful in many food applications such as food supplement and edible oil extraction.

A study was conducted to assess the status of the women workers in rice processing activities among five Upazilas of Sherpur district, Nalitabari and Nokla Upazila. Random sampling was employed to collect data and 110 respondents taken as sample from 880 enlisted populations were prepared by researcher herself with the help of local NGO workers from these two Upazilas. Data were collected using predesigned interview schedule. Majority of the respondents were young and middle aged. Besides Educational status is quite frustrating because of higher illiterate percentage. Most of the lands were taken as mortgage or rent. Since their socioeconomic status were not up to the mark, that was why it can be perceived that their occupation were not very much sound. That was why quantitatively, it was brought that most of the respondents were mill workers. In the house hold, female were the higher performer than male in case of rice processing activities. On the other hand it is found inverse relation in case of rice mill. But it was observed that overall performance was higher in case of female workers in both environment i.e. household and rice mill. Education and farm income is the major influential factors on the workers daily working hours. If consideration can be made on the physical work environment, “No plantation in the mill yard” and “No good facility of aeration in mill house” were the immense problem. In case of economical problem, there are two major problems viz. “No security for holding job” and “No salary when leave taken”. Moreover “No facility for recreations”, “No health check up facility”, “No facility for consulting with doctors” and “No insurance for accident” were the problems regarding health issues.